Publications by authors named "David Piwnica-Worms"

199 Publications

Directed evolution of cyclic peptides for inhibition of autophagy.

Chem Sci 2021 Jan 13;12(10):3526-3543. Epub 2021 Jan 13.

Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center USA

In recent decades it has become increasingly clear that induction of autophagy plays an important role in the development of treatment resistance and dormancy in many cancer types. Unfortunately, chloroquine (CQ) and hydroxychloroquine (HCQ), two autophagy inhibitors in clinical trials, suffer from poor pharmacokinetics and high toxicity at therapeutic dosages. This has prompted intense interest in the development of targeted autophagy inhibitors to re-sensitize disease to treatment with minimal impact on normal tissue. We utilized Scanning Unnatural Protease Resistant (SUPR) mRNA display to develop macrocyclic peptides targeting the autophagy protein LC3. The resulting peptides bound LC3A and LC3B-two essential components of the autophagosome maturation machinery-with mid-nanomolar affinities and disrupted protein-protein interactions (PPIs) between LC3 and its binding partners . The most promising LC3-binding SUPR peptide accessed the cytosol at low micromolar concentrations as measured by chloroalkane penetration assay (CAPA) and inhibited starvation-mediated GFP-LC3 puncta formation in a concentration-dependent manner. LC3-binding SUPR peptides re-sensitized platinum-resistant ovarian cancer cells to cisplatin treatment and triggered accumulation of the adapter protein p62 suggesting decreased autophagic flux through successful disruption of LC3 PPIs in cell culture. In mouse models of metastatic ovarian cancer, treatment with LC3-binding SUPR peptides and carboplatin resulted in almost complete inhibition of tumor growth after four weeks of treatment. These results indicate that SUPR peptide mRNA display can be used to develop cell-penetrating macrocyclic peptides that target and disrupt the autophagic machinery and .
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0sc03603jDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8179393PMC
January 2021

Excess exogenous pyruvate inhibits lactate dehydrogenase activity in live cells in an MCT1-dependent manner.

J Biol Chem 2021 07 20;297(1):100775. Epub 2021 May 20.

Department of Cancer System Imaging, University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA. Electronic address:

Cellular pyruvate is an essential metabolite at the crossroads of glycolysis and oxidative phosphorylation, capable of supporting fermentative glycolysis by reduction to lactate mediated by lactate dehydrogenase (LDH) among other functions. Several inherited diseases of mitochondrial metabolism impact extracellular (plasma) pyruvate concentrations, and [1-C]pyruvate infusion is used in isotope-labeled metabolic tracing studies, including hyperpolarized magnetic resonance spectroscopic imaging. However, how these extracellular pyruvate sources impact intracellular metabolism is not clear. Herein, we examined the effects of excess exogenous pyruvate on intracellular LDH activity, extracellular acidification rates (ECARs) as a measure of lactate production, and hyperpolarized [1-C]pyruvate-to-[1-C]lactate conversion rates across a panel of tumor and normal cells. Combined LDH activity and LDHB/LDHA expression analysis intimated various heterotetrameric isoforms comprising LDHA and LDHB in tumor cells, not only canonical LDHA. Millimolar concentrations of exogenous pyruvate induced substrate inhibition of LDH activity in both enzymatic assays ex vivo and in live cells, abrogated glycolytic ECAR, and inhibited hyperpolarized [1-C]pyruvate-to-[1-C]lactate conversion rates in cellulo. Of importance, the extent of exogenous pyruvate-induced inhibition of LDH and glycolytic ECAR in live cells was highly dependent on pyruvate influx, functionally mediated by monocarboxylate transporter-1 localized to the plasma membrane. These data provided evidence that highly concentrated bolus injections of pyruvate in vivo may transiently inhibit LDH activity in a tissue type- and monocarboxylate transporter-1-dependent manner. Maintaining plasma pyruvate at submillimolar concentrations could potentially minimize transient metabolic perturbations, improve pyruvate therapy, and enhance quantification of metabolic studies, including hyperpolarized [1-C]pyruvate magnetic resonance spectroscopic imaging and stable isotope tracer experiments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jbc.2021.100775DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8233206PMC
July 2021

A Reversible Shift of Driver Dependence from EGFR to Notch1 in Non-Small Cell Lung Cancer as a Cause of Resistance to Tyrosine Kinase Inhibitors.

Cancers (Basel) 2021 Apr 22;13(9). Epub 2021 Apr 22.

Department of Advanced Biomedical Sciences, University "Federico II", 80131 Naples, Italy.

Notch1 plays a key role in epithelial-mesenchymal transition (EMT) and in the maintenance of cancer stem cells. In the present study we tested whether high levels of activated Notch1 in oncogene-driven NSCLC can induce a reversible shift of driver dependence from EGFR to Notch1, and thus causing resistance to EGFR inhibitors. Adherent cells (parental) and tumor spheres (TS) from NSCLC H1975 cells and patient-derived CD133-positive cells were tested for EGFR and Notch1 signaling cascade. The Notch1-dependent modulation of EGFR, NCID, Hes1, p53, and Sp1 were then analyzed in parental cells by binding assays with a Notch1 agonist, DLL4. TS were more resistant than parental cells to EGFR inhibitors. A strong upregulation of Notch1 and a concomitant downregulation of EGFR were observed in TS compared to parental cells. Parental cell exposure to DLL4 showed a dose-dependent decrease of EGFR and a simultaneous increase of NCID, Hes1, p53, and Sp1, along with the dislocation of Sp1 from the promoter. Furthermore, an enhanced interaction between p53 and Sp1 was observed in TS. In NSCLC cells, high levels of active Notch1 can promote a reversible shift of driver dependence from EGFR to Notch1, leading to resistance to EGFR inhibitors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cancers13092022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8122511PMC
April 2021

Myeloid cell-derived HOCl is a paracrine effector that trans-inhibits IKK/NF-κB in melanoma cells and limits early tumor progression.

Sci Signal 2021 Apr 6;14(677). Epub 2021 Apr 6.

Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.

The myeloperoxidase (MPO) system of myeloid-derived cells (MDCs) is central to cellular innate immunity. Upon MDC activation, MPO is secreted into phagosomes where it catalyzes the production of hypochlorous acid (HOCl), a potent chlorinating oxidant. Here, we demonstrated that the myeloid lineage-restricted MPO-HOCl system had antitumor effects in early melanoma growth in aged mice. Orthotopic melanomas grew more slowly in immunocompetent host mice compared to age-matched syngeneic mice. Real-time intravital tumor imaging in vivo and in cell cocultures revealed a cell-cell proximity-dependent association between MDC-derived MPO enzyme activity and blockade of ligand-induced IκBα degradation in tumor cells. HOCl directly trans-inhibited IκB kinase (IKK) activity in tumor cells, thereby decreasing nuclear factor κB (NF-κB) transcriptional activation and inducing changes in the expression of genes involved in metabolic pathways, cell cycle progression, and DNA replication. By contrast, HOCl induced transcriptional changes in CD8 T cells related to ion transport and the MAPK and PI3K-AKT signaling pathways that are associated with T cell activation. MPO increased the circulating concentrations of the myeloid cell-attracting cytokines CXCL1 and CXCL5, enhanced local infiltration by CD8 cytotoxic T cells, and decreased tumor growth. Overall, these data reveal a role for MDC-derived HOCl as a small-molecule paracrine signaling factor that trans-inhibits IKK in melanoma tumor cells, mediating antitumor responses during early tumor progression.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/scisignal.aax5971DOI Listing
April 2021

Multi-Modal Multi-Spectral Intravital Macroscopic Imaging of Signaling Dynamics in Real Time during Tumor-Immune Interactions.

Cells 2021 02 25;10(3). Epub 2021 Feb 25.

Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.

A major obstacle in studying the interplay between cancer cells and the immune system has been the examination of proposed biological pathways and cell interactions in a dynamic, physiologically relevant system in vivo. Intravital imaging strategies are one of the few molecular imaging techniques that can follow biological processes at cellular resolution over long periods of time in the same individual. Bioluminescence imaging has become a standard preclinical in vivo optical imaging technique with ever-expanding versatility as a result of the development of new emission bioluminescent reporters, advances in genomic techniques, and technical improvements in bioluminescence imaging and processing methods. Herein, we describe an advance of technology with a molecular imaging window chamber platform that combines bioluminescent and fluorescent reporters with intravital macro-imaging techniques and bioluminescence spectral unmixing in real time applied to heterogeneous living systems in vivo for evaluating tumor signaling dynamics and immune cell enzyme activities concurrently.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cells10030489DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996138PMC
February 2021

Multi-Modal Multi-Spectral Intravital Microscopic Imaging of Signaling Dynamics in Real-Time during Tumor-ImmuneInteractions.

Cells 2021 02 26;10(3). Epub 2021 Feb 26.

Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.

Intravital microscopic imaging (IVM) allows for the study of interactions between immune cells and tumor cells in a dynamic, physiologically relevant system in vivo. Current IVM strategies primarily use fluorescence imaging; however, with the advances in bioluminescence imaging and the development of new bioluminescent reporters with expanded emission spectra, the applications for bioluminescence are extending to single cell imaging. Herein, we describe a molecular imaging window chamber platform that uniquely combines both bioluminescent and fluorescent genetically encoded reporters, as well as exogenous reporters, providing a powerful multi-plex strategy to study molecular and cellular processes in real-time in intact living systems at single cell resolution all in one system. We demonstrate that our molecular imaging window chamber platform is capable of imaging signaling dynamics in real-time at cellular resolution during tumor progression. Importantly, we expand the utility of IVM by modifying an off-the-shelf commercial system with the addition of bioluminescence imaging achieved by the addition of a CCD camera and demonstrate high quality imaging within the reaches of any biology laboratory.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cells10030499DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996937PMC
February 2021

Hyperpolarized [1-C]pyruvate-to-[1-C]lactate conversion is rate-limited by monocarboxylate transporter-1 in the plasma membrane.

Proc Natl Acad Sci U S A 2020 09 24;117(36):22378-22389. Epub 2020 Aug 24.

Department of Cancer System Imaging, University of Texas MD Anderson Cancer Center, Houston, TX 77030;

Hyperpolarized [1-C]pyruvate magnetic resonance spectroscopic imaging (MRSI) is a noninvasive metabolic-imaging modality that probes carbon flux in tissues and infers the state of metabolic reprograming in tumors. Prevailing models attribute elevated hyperpolarized [1-C]pyruvate-to-[1-C]lactate conversion rates in aggressive tumors to enhanced glycolytic flux and lactate dehydrogenase A (LDHA) activity (Warburg effect). By contrast, we find by cross-sectional analysis using genetic and pharmacological tools in mechanistic studies applied to well-defined genetically engineered cell lines and tumors that initial hyperpolarized [1-C]pyruvate-to-[1-C]lactate conversion rates as well as global conversion were highly dependent on and critically rate-limited by the transmembrane influx of [1-C]pyruvate mediated predominately by monocarboxylate transporter-1 (MCT1). Specifically, in a cell-encapsulated alginate bead model, induced short hairpin (shRNA) knockdown or overexpression of MCT1 quantitatively inhibited or enhanced, respectively, unidirectional pyruvate influxes and [1-C]pyruvate-to-[1-C]lactate conversion rates, independent of glycolysis or LDHA activity. Similarly, in tumor models in vivo, hyperpolarized [1-C]pyruvate-to-[1-C]lactate conversion was highly dependent on and critically rate-limited by the induced transmembrane influx of [1-C]pyruvate mediated by MCT1. Thus, hyperpolarized [1-C]pyruvate MRSI measures primarily MCT1-mediated [1-C]pyruvate transmembrane influx in vivo, not glycolytic flux or LDHA activity, driving a reinterpretation of this maturing new technology during clinical translation. Indeed, Kaplan-Meier survival analysis for patients with pancreatic, renal, lung, and cervical cancers showed that high-level expression of MCT1 correlated with poor overall survival, and only in selected tumors, coincident with LDHA expression. Thus, hyperpolarized [1-C]pyruvate MRSI provides a noninvasive functional assessment primarily of MCT1 as a clinical biomarker in relevant patient populations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.2003537117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7486767PMC
September 2020

Interrogating Cellular Communication in Cancer with Genetically Encoded Imaging Reporters.

Radiol Imaging Cancer 2020 07 31;2(4):e190053. Epub 2020 Jul 31.

Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, 1881 E Road, Houston, TX 77054.

Cells continuously communicate changes in their microenvironment, both locally and globally, with other cells in the organism. Integration of information arising from signaling networks impart continuous, time-dependent changes of cell function and phenotype. Use of genetically encoded reporters enable researchers to noninvasively monitor time-dependent changes in intercellular and intracellular signaling, which can be interrogated by macroscopic and microscopic optical imaging, nuclear medicine imaging, MRI, and even photoacoustic imaging techniques. Reporters enable noninvasive monitoring of changes in cell-to-cell proximity, transcription, translation, protein folding, protein association, protein degradation, drug action, and second messengers in real time. Because of their positive impact on preclinical research, attempts to improve the sensitivity and specificity of these reporters, and to develop new types and classes of reporters, remain an active area of investigation. A few reporters have migrated to proof-of-principle clinical demonstrations, and recent advances in genome editing technologies may enable the use of reporters in the context of genome-wide analysis and the imaging of complex genomic regulation in vivo that cannot be readily investigated through standard methodologies. The combination of genetically encoded imaging reporters with continuous improvements in other molecular biology techniques may enhance and expedite target discovery and drug development for cancer interventions and treatment. © RSNA, 2020.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1148/rycan.2020190053DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7398120PMC
July 2020

Streamlining the Quantitative Metrics Workflow at a Comprehensive Cancer Center.

Acad Radiol 2021 10 21;28(10):1401-1407. Epub 2020 Jul 21.

Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030. Electronic address:

Introduction: The objective of the project was to describe an efficient workflow for quantifying and disseminating tumor imaging metrics essential for assessing tumor response in clinical therapeutic trials. The clinical research utility of integration of the workflow into the electronic health record for radiology reporting was measured before and after the intervention.

Materials And Methods: A search of institutional clinical trial databases was performed to identify trials with radiology department collaborators. Investigator initiated trials, or those which lacked a standardized or automated system of collaboration with the research team were selected for the study. A web based application integrated in the electronic health record platform, the Quantitative Imaging Analysis Core (QIAC) initiative was established as a divisional resource with institutional support to provide standardized and reproducible imaging metrics across the institution. The turnaround time for radiology reports before (phase 1) and after web based application workflow (phase 2) was measured. During our test period (November 2014 to June 2015), a total of 68 requests with 37 from phase 1 and 31 from phase 2 were analyzed for patients who were enrolled in prospective clinical therapeutic interventional trials.

Results: The mean turnaround time for generation of quantitative tumor metric results after implementation of the web based QIAC workflow (phase 2) was significantly lower than prior (phase 1) (15.9 ± 21.3 vs 31.7 ± 35.4 hours, p= 0.0005). The mean time from the scan to the preliminary assessment was 19.6 ± 25.6 hours before and significantly reduced to 8.0 ± 9.9 hours with implementation of web based QIAC workflow.

Conclusion: Implementation of a web based QIAC workflow platform enabled significantly improved turnaround time for quantitative tumor metrics reports and enabled faster access to the reports.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.acra.2020.06.014DOI Listing
October 2021

Mistiming Death: Modeling the Time-Domain Variability of Tumor Apoptosis and Implications for Molecular Imaging of Cell Death.

Mol Imaging Biol 2020 10;22(5):1310-1323

Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX, USA.

Purpose: Apoptosis, in the context of cancer, is a form of programmed cell death induced by chemotherapy, radiotherapy, and immunotherapy. As this is a central pathway in treatment response, considerable effort has been expended on the development of molecular imaging agents to non-invasively measure tumor apoptosis prior to quantitative changes in tumor dimensions. Despite these efforts, clinical trials directed at imaging apoptosis by PET, SPECT, and MRI have failed to robustly predict response to treatment with high sensitivity and specificity. Although these shortcomings may be linked to probe design, we propose that the combination of variability in the timing of maximal in vivo tumor apoptosis and sub-optimal sampling times fundamentally limits the predictive power of PET/SPECT apoptosis imaging.

Procedures: Herein, we surveyed the literature describing the time course of therapy-induced tumor apoptosis in vivo and used these data to construct a mathematical model describing the onset, duration, amplitude, and variability of the apoptotic response. Uncertainty in the underlying time of initiation of tumor apoptosis was simulated by Gaussian, uniform, and Landau distributions centered at the median time-to-maximum apoptotic rate derived from the literature. We then computationally sampled these models for various durations to simulate PET/SPECT imaging agents with variable effective half-lives.

Results: Models with a narrow Gaussian distribution of initiation times for tumor apoptosis predicted high contrast ratios and strong predictive values for all effective tracer half-lives. However, when uncertainty in apoptosis initiation times were simulated with uniform and Landau distributions, high contrast ratios and predictive values were only obtained with extremely long imaging windows (days). The imaging contrast ratios predicted in these models were consistent with those seen in pre-clinical apoptosis PET/SPECT imaging studies and suggest that uncertainty in the timing of tumor cell death plays a significant role in the maximal contrast obtainable. Moreover, when uncertainty in both apoptosis initiation and imaging start times were simulated, the predicted contrast ratios were dramatically reduced for all tracer half-lives.

Conclusions: These studies illustrate the effect of uncertainty of apoptosis initiation on the predictive power of PET/SPECT apoptosis imaging agents and suggest that long integration times are required to surmount uncertainty in the time domain of this biological process.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11307-020-01509-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8279023PMC
October 2020

Early Detection of Pancreatic Intraepithelial Neoplasias (PanINs) in Transgenic Mouse Model by Hyperpolarized C Metabolic Magnetic Resonance Spectroscopy.

Int J Mol Sci 2020 May 25;21(10). Epub 2020 May 25.

Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA.

While pancreatic cancer (PC) survival rates have recently shown modest improvement, the disease remains largely incurable. Early detection of pancreatic cancer may result in improved outcomes and therefore, methods for early detection of cancer, even premalignant lesions, may provide more favorable outcomes. Pancreatic intraepithelial neoplasias (PanINs) have been identified as premalignant precursor lesions to pancreatic cancer. However, conventional imaging methods used for screening high-risk populations do not have the sensitivity to detect PanINs. Here, we have employed hyperpolarized metabolic imaging in vivo and nuclear magnetic resonance (H-NMR) metabolomics ex vivo to identify and understand metabolic changes, towards enabling detection of early PanINs and progression to advanced PanINs lesions that precede pancreatic cancer formation. Progression of disease from tissue containing predominantly low-grade PanINs to tissue with high-grade PanINs showed a decreasing alanine/lactate ratio from high-resolution NMR metabolomics ex vivo. Hyperpolarized magnetic resonance spectroscopy (HP-MRS) allows over 10,000-fold sensitivity enhancement relative to conventional magnetic resonance. Real-time HP-MRS was employed to measure non-invasively changes of alanine and lactate metabolites with disease progression and in control mice in vivo, following injection of hyperpolarized [1-C] pyruvate. The alanine-to-lactate signal intensity ratio was found to decrease as the disease progressed from low-grade PanINs to high-grade PanINs. The biochemical changes of alanine transaminase (ALT) and lactate dehydrogenase (LDH) enzyme activity were assessed. These results demonstrate that there are significant alterations of ALT and LDH activities during the transformation from early to advanced PanINs lesions. Furthermore, we demonstrate that real-time conversion kinetic rate constants (k and k) can be used as metabolic imaging biomarkers of pancreatic premalignant lesions. Findings from this emerging HP-MRS technique can be translated to the clinic for detection of pancreatic premalignant lesion in high-risk populations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms21103722DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7279395PMC
May 2020

Axonal Transport as an In Vivo Biomarker for Retinal Neuropathy.

Cells 2020 05 22;9(5). Epub 2020 May 22.

Department of Neuroradiology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.

We illuminate a possible explanatory pathophysiologic mechanism for retinal cellular neuropathy by means of a novel diagnostic method using ophthalmoscopic imaging and a molecular imaging agent targeted to fast axonal transport. The retinal neuropathies are a group of diseases with damage to retinal neural elements. Retinopathies lead to blindness but are typically diagnosed late, when substantial neuronal loss and vision loss have already occurred. We devised a fluorescent imaging agent based on the non-toxic C fragment of tetanus toxin (TTc), which is taken up and transported in neurons using the highly conserved fast axonal transport mechanism. TTc serves as an imaging biomarker for normal axonal transport and demonstrates impairment of axonal transport early in the course of an N-methyl-D-aspartic acid (NMDA)-induced excitotoxic retinopathy model in rats. Transport-related imaging findings were dramatically different between normal and retinopathic eyes prior to presumed neuronal cell death. This proof-of-concept study provides justification for future clinical translation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cells9051298DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7291064PMC
May 2020

Analysis of RAS protein interactions in living cells reveals a mechanism for pan-RAS depletion by membrane-targeted RAS binders.

Proc Natl Acad Sci U S A 2020 06 18;117(22):12121-12130. Epub 2020 May 18.

Gene Expression Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037;

HRAS, NRAS, and KRAS4A/KRAS4B comprise the RAS family of small GTPases that regulate signaling pathways controlling cell proliferation, differentiation, and survival. RAS pathway abnormalities cause developmental disorders and cancers. We found that KRAS4B colocalizes on the cell membrane with other RAS isoforms and a subset of prenylated small GTPase family members using a live-cell quantitative split luciferase complementation assay. RAS protein coclustering is mainly mediated by membrane association-facilitated interactions (MAFIs). Using the RAS-RBD (CRAF RAS binding domain) interaction as a model system, we showed that MAFI alone is not sufficient to induce RBD-mediated RAS inhibition. Surprisingly, we discovered that high-affinity membrane-targeted RAS binding proteins inhibit RAS activity and deplete RAS proteins through an autophagosome-lysosome-mediated degradation pathway. Our results provide a mechanism for regulating RAS activity and protein levels, a more detailed understanding of which should lead to therapeutic strategies for inhibiting and depleting oncogenic RAS proteins.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.2000848117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7275768PMC
June 2020

F-fluorodeoxyglucose positron emission tomography correlates with tumor immunometabolic phenotypes in resected lung cancer.

Cancer Immunol Immunother 2020 Aug 16;69(8):1519-1534. Epub 2020 Apr 16.

Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Unit 432, Houston, TX, 77030, USA.

Enhanced tumor glycolytic activity is a mechanism by which tumors induce an immunosuppressive environment to resist adoptive T cell therapy; therefore, methods of assessing intratumoral glycolytic activity are of considerable clinical interest. In this study, we characterized the relationships among tumor F-fluorodeoxyglucose (FDG) retention, tumor metabolic and immune phenotypes, and survival in patients with resected non-small cell lung cancer (NSCLC). We retrospectively analyzed tumor preoperative positron emission tomography (PET) F-FDG uptake in 59 resected NSCLCs and investigated correlations between PET parameters (SUV, SUV, SUV, TLG), tumor expression of glycolysis- and immune-related genes, and tumor-associated immune cell densities that were quantified by immunohistochemistry. Tumor glycolysis-associated immune gene signatures were analyzed for associations with survival outcomes. We found that each F-FDG PET parameter was positively correlated with tumor expression of glycolysis-related genes. Elevated F-FDG SUV was more discriminatory of glycolysis-associated changes in tumor immune phenotypes than other F-FDG PET parameters. Increased SUV was associated with multiple immune factors characteristic of an immunosuppressive and poorly immune infiltrated tumor microenvironment, including elevated PD-L1 expression, reduced CD57 cell density, and increased T cell exhaustion gene signature. Elevated SUV identified immune-related transcriptomic signatures that were associated with enhanced tumor glycolytic gene expression and poor clinical outcomes. Our results suggest that F-FDG SUV has potential value as a noninvasive, clinical indicator of tumor immunometabolic phenotypes in patients with resectable NSCLC and warrants investigation as a potential predictor of therapeutic response to immune-based treatment strategies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00262-020-02560-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7997043PMC
August 2020

Induction of antitumor immunity in mice by the combination of nanoparticle-based photothermolysis and anti-PD-1 checkpoint inhibition.

Nanomedicine 2020 04 12;25:102169. Epub 2020 Feb 12.

Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA. Electronic address:

Generation of durable tumor-specific immune response without isolation and expansion of dendritic cells or T cells ex vivo remains a challenge. In this study, we investigated the impact of nanoparticle-mediated photothermolysis in combination with checkpoint inhibition on the induction of systemic antitumor immunity. Photothermolysis based on near-infrared light-absorbing copper sulfide nanoparticles and 15-ns laser pulses combined with the immune checkpoint inhibitor anti-PD-1 antibody (αPD-1) increased tumor infiltration by antigen-presenting cells and CD8-positive T lymphocytes in the B16-OVA mouse model. Moreover, combined photothermolysis, polymeric conjugate of the Toll-like receptor 9 agonist CpG, and αPD-1 significantly prolonged mouse survival after re-inoculation of tumor cells at a distant site compared to individual treatments alone in the poorly immunogenic syngeneic ID8-ip1-Luc ovarian tumor model. Thus, photothermolysis is a promising interventional technique that synergizes with Toll-like receptor 9 agonists and immune checkpoint inhibitors to enhance the abscopal effect in tumors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.nano.2020.102169DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7181381PMC
April 2020

Mechanism-Specific Pharmacodynamics of a Novel Complex-I Inhibitor Quantified by Imaging Reversal of Consumptive Hypoxia with [F]FAZA PET .

Cells 2019 11 21;8(12). Epub 2019 Nov 21.

Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.

Tumors lack a well-regulated vascular supply of O and often fail to balance O supply and demand. Net O tension within many tumors may not only depend on O delivery but also depend strongly on O demand. Thus, tumor O consumption rates may influence tumor hypoxia up to true anoxia. Recent reports have shown that many human tumors in vivo depend primarily on oxidative phosphorylation (OxPhos), not glycolysis, for energy generation, providing a driver for consumptive hypoxia and an exploitable vulnerability. In this regard, IACS-010759 is a novel high affinity inhibitor of OxPhos targeting mitochondrial complex-I that has recently completed a Phase-I clinical trial in leukemia. However, in solid tumors, the effective translation of OxPhos inhibitors requires methods to monitor pharmacodynamics in vivo. Herein, F-fluoroazomycin arabinoside ([F]FAZA), a 2-nitroimidazole-based hypoxia PET imaging agent, was combined with a rigorous test-retest imaging method for non-invasive quantification of the reversal of consumptive hypoxia in vivo as a mechanism-specific pharmacodynamic (PD) biomarker of target engagement for IACS-010759. Neither cell death nor loss of perfusion could account for the IACS-010759-induced decrease in [F]FAZA retention. Notably, in an OxPhos-reliant melanoma tumor, a titration curve using [F]FAZA PET retention in vivo yielded an IC for IACS-010759 (1.4 mg/kg) equivalent to analysis ex vivo. Pilot [F]FAZA PET scans of a patient with grade IV glioblastoma yielded highly reproducible, high-contrast images of hypoxia in vivo as validated by CA-IX and GLUT-1 IHC ex vivo. Thus, [F]FAZA PET imaging provided direct evidence for the presence of consumptive hypoxia in vivo, the capacity for targeted reversal of consumptive hypoxia through the inhibition of OxPhos, and a highly-coupled mechanism-specific PD biomarker ready for translation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cells8121487DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6952969PMC
November 2019

A Novel Mitochondrial Inhibitor Blocks MAPK Pathway and Overcomes MAPK Inhibitor Resistance in Melanoma.

Clin Cancer Res 2019 11 22;25(21):6429-6442. Epub 2019 Aug 22.

Department of Melanoma Medical Oncology, University of Texas M.D. Anderson Cancer Center, Houston, Texas.

Purpose: The purpose of this study is to determine if inhibition of mitochondrial oxidative phosphorylation (OxPhos) is an effective strategy against MAPK pathway inhibitor (MAPKi)-resistant BRAF-mutant melanomas. The antimelanoma activity of IACS-010759 (OPi), a novel OxPhos complex I inhibitor, was evaluated and . Mechanistic studies and predictors of response were evaluated using molecularly and metabolically stratified melanoma cell lines. C-labeling and targeted metabolomics were used to evaluate the effect of OPi on cellular energy utilization. OxPhos inhibition was evaluated noninvasively by [F]-fluoroazomycin arabinoside (FAZA) PET imaging.

Results: OPi potently inhibited OxPhos and the growth of multiple MAPKi-resistant BRAF-mutant melanoma models with high OxPhos at well-tolerated doses. tumor regression with single-agent OPi treatment correlated with inhibition of both MAPK and mTOR complex I activity. Unexpectedly, antitumor activity was not improved by combined treatment with MAPKi or . Signaling and growth-inhibitory effects were mediated by LKB1-AMPK axis, and proportional to AMPK activation. OPi increased glucose incorporation into glycolysis, inhibited glucose and glutamine incorporation into the mitochondrial tricarboxylic acid cycle, and decreased cellular nucleotide and amino acid pools. Early changes in [F]-FAZA PET uptake , and the degree of mTORC1 pathway inhibition , correlated with efficacy.

Conclusions: Targeting OxPhos with OPi has significant antitumor activity in MAPKi-resistant, BRAF-mutant melanomas, and merits further clinical investigation as a potential new strategy to overcome intrinsic and acquired resistance to MAPKi in patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/1078-0432.CCR-19-0836DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6825560PMC
November 2019

Novel derivatives of anaplastic lymphoma kinase inhibitors: Synthesis, radiolabeling, and preliminary biological studies of fluoroethyl analogues of crizotinib, alectinib, and ceritinib.

Eur J Med Chem 2019 Nov 9;182:111571. Epub 2019 Aug 9.

Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA. Electronic address:

Anaplastic lymphoma kinase (ALK), an oncogenic receptor tyrosine kinase, is a therapeutic target in various cancers, including non-small cell lung cancer. Although several ALK inhibitors, including crizotinib, ceritinib, and alectinib, are approved for cancer treatment, their long-term benefit is often limited by the cancer's acquisition of resistance owing to secondary point mutations in ALK. Importantly, some ALK inhibitors cannot cross the blood-brain barrier (BBB) and thus have little or no efficacy against brain metastases. The introduction of a lipophilic moiety, such as a fluoroethyl group may improve the drug's BBB penetration. Herein, we report the synthesis of fluoroethyl analogues of crizotinib 1, alectinib 4, and ceritinib 9, and their radiolabeling with F for pharmacokinetic studies. The fluoroethyl derivatives and their radioactive analogues were obtained in good yields with high purity and good molar activity. A cytotoxicity screen in ALK-expressing H2228 lung cancer cells showed that the analogues had up to nanomolar potency and the addition of the fluorinated moiety had minimal impact overall on the potency of the original drugs. Positron emission tomography in healthy mice showed that the analogues had enhanced BBB penetration, suggesting that they have therapeutic potential against central nervous system metastases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejmech.2019.111571DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7193943PMC
November 2019

Assessing Metabolic Intervention with a Glutaminase Inhibitor in Real-Time by Hyperpolarized Magnetic Resonance in Acute Myeloid Leukemia.

Mol Cancer Ther 2019 11 6;18(11):1937-1946. Epub 2019 Aug 6.

Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, Texas.

Acute myeloid leukemia (AML) is an aggressive hematopoietic disease characterized by glutamine-dependent metabolism. A novel glutaminase (GLS) inhibitor, CB-839, is currently under evaluation for treatment of hematopoietic malignancies and solid tumors. Our purpose was to measure cellular changes in AML associated with CB-839 treatment and to test the ability of hyperpolarized pyruvate for interrogating these changes to OCI-AML3 cells. Our results show that treatment with CB-839 interfered with the citric acid cycle, reduced the NADH/NAD ratio and ATP levels, reduced cell proliferation and viability, and reduced the basal and maximal respiratory capacities [oxygen consumption rate (OCR)]. We observed a reduction of the conversion of hyperpolarized pyruvate to lactate in cell lines and in a mouse AML model after CB-839 treatment. Our and results support the hypothesis that, in AML, glutamine is utilized to generate reducing equivalents (NADH, FADH) through the citric acid cycle and that reduction in redox state by GLS inhibition decreases the rate of pyruvate to lactate conversion catalyzed by lactate dehydrogenase. We propose hyperpolarized pyruvate/lactate measurement as a method for direct monitoring of metabolic changes occurring in AML patients receiving CB-839. With further optimization, this method may provide a noninvasive imaging tool to assess the early efficacy of therapeutic intervention with GLS inhibitors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/1535-7163.MCT-18-0985DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7080291PMC
November 2019

Combining Hyperpolarized Real-Time Metabolic Imaging and NMR Spectroscopy To Identify Metabolic Biomarkers in Pancreatic Cancer.

J Proteome Res 2019 07 4;18(7):2826-2834. Epub 2019 Jun 4.

Department of Gastrointestinal Oncology , H. Lee Moffitt Cancer Center , Tampa , Florida 33612 , United States.

Pancreatic ductal adenocarcinoma (PDAC) is a deadly cancer that progresses without any symptom, and oftentimes, it is detected at an advanced stage. The lack of prior symptoms and effective treatments have created a knowledge gap in the management of this lethal disease. This issue can be addressed by developing novel noninvasive imaging-based biomarkers in PDAC. We explored in vivo hyperpolarized (HP) C MRS of pyruvate to lactate conversion and ex vivo H NMR spectroscopy in a panel of well-annotated patient-derived PDAC xenograft (PDXs) model and investigated the correlation between aberrant glycolytic metabolism and aggressiveness of the tumor. Real-time metabolic imaging data demonstrate the immediate intracellular conversion of HP C pyruvate to lactate after intravenous injection interrogating upregulated lactate dehydrogenase (LDH) activity in aggressive PDXs. Total ex vivo lactate measurement by H NMR spectroscopy showed a direct correlation with in vivo dynamic pyruvate-to-lactate conversion and demonstrated the potential of dynamic metabolic flux as a biomarker of total lactate concentration and aggressiveness of the tumor. Furthermore, the metabolite concentrations were very distinct among all four tumor types analyzed in this study. Overexpression of LDH-A and hypoxia-inducible factor (HIF-1α) plays a significant role in the conversion kinetics of HP pyruvate-to-lactate in tumors. Collectively, these data identified aberrant metabolic characteristics of pancreatic cancer PDXs and could potentially delineate metabolic targets for therapeutic intervention. Metabolic imaging with HP pyruvate and NMR metabolomics may enable identification and classification of aggressive subtypes of patient-derived xenografts. Translation of this real-time metabolic technique to the clinic may have the potential to improve the management of patients at high risk of developing pancreatic diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.jproteome.9b00132DOI Listing
July 2019

Multiwalled Carbon Nanotubes for Combination Therapy: a Biodistribution and Efficacy Pilot Study.

J Mater Chem B 2019 04 12;7(16):2678-2687. Epub 2019 Mar 12.

Department of Cancer Systems Imaging, Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, 1881 East Road, 77054 Houston, TX, USA.

A drug delivery system (DDS) for combined therapy, based on a short oxidized multiwalled carbon nanotube, is reported. It was prepared exploiting a synthetic approach which allowed loading of two drugs, doxorubicin and metformin, the targeting agent biotin and a radiolabeling tag, to enable labeling with Ga-68 or Cu-64 in order to perform an extensive biodistribution study by PET/CT. The DDS biodistribution profile changes with different administration methods. Once administered at therapeutic doses, the DDS showed a marginal beneficial effect on 4T1 tumor bearing mice, a syngeneic and orthotopic model of triple negative breast cancer, with survival extended by 1 week and 2 days in 20% of the mice. This is encouraging given the aggressiveness of the 4T1 tumor. Furthermore our DDS was well tolerated, ruling out concerns regarding the toxicity of carbon nanotubes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/C8TB03299HDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6501563PMC
April 2019

Development of a Potential Gallium-68-Labelled Radiotracer Based on DOTA-Curcumin for Colon-Rectal Carcinoma: From Synthesis to In Vivo Studies.

Molecules 2019 Feb 12;24(3). Epub 2019 Feb 12.

Radiopharmaceutical Chemistry Unit, Oncologic and High Technologies Department, Azienda USL-IRCCS, via Amendola 2, 42122 Reggio Emilia, Italy.

Colorectal cancer is the third most commonly occurring cancer in men and the second most commonly occurring cancer in women worldwide. We have recently reported that curcuminoid complexes labelled with gallium-68 have demonstrated preferential uptake in HT29 colorectal cancer and K562 lymphoma cell lines compared to normal human lymphocytes. In the present study, we report a new gallium-68-labelled curcumin derivative (Ga-DOTA-C21) and its initial validation as marker for early detection of colorectal cancer. The precursor and non-radioactive complexes were synthesized and deeply characterized by analytical methods then the curcuminoid was radiolabelled with gallium-68. The in vitro stability, cell uptake, internalization and efflux properties of the probe were studied in HT29 cells, and the in vivo targeting ability and biodistribution were investigated in mice bearing HT29 subcutaneous tumour model. Ga-DOTA-C21 exhibits decent stability (57 ± 3% after 120 min of incubation) in physiological media and a curcumin-mediated cellular accumulation in colorectal cancer cell line (121 ± 4 KBq of radiotracer per mg of protein within 60 min of incubation). In HT29 tumour-bearing mice, the tumour uptake of Ga-DOTA-C21 is 3.57 ± 0.3% of the injected dose per gram of tissue after 90 min post injection with a tumour to muscle ratio of 2.2 ± 0.2. High amount of activity (12.73 ± 1.9% ID/g) is recorded in blood and significant uptake of the radiotracer occurs in the intestine (13.56 ± 3.3% ID/g), lungs (8.42 ± 0.8% ID/g), liver (5.81 ± 0.5% ID/g) and heart (4.70 ± 0.4% ID/g). Further studies are needed to understand the mechanism of accumulation and clearance; however, Ga-DOTA-C21 provides a productive base-structure to develop further radiotracers for imaging of colorectal cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/molecules24030644DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6384893PMC
February 2019

Caspase-3 Substrates for Noninvasive Pharmacodynamic Imaging of Apoptosis by PET/CT.

Bioconjug Chem 2018 09 31;29(9):3180-3195. Epub 2018 Aug 31.

School of Biomedical Informatics , The University of Texas Health Science Center at Houston , Houston , Texas 77030 , United States.

Quantitative imaging of apoptosis in vivo could enable real-time monitoring of acute cell death pathologies such as traumatic brain injury, as well as the efficacy and safety of cancer therapy. Here, we describe the development and validation of F-18-labeled caspase-3 substrates for PET/CT imaging of apoptosis. Preliminary studies identified the O-benzylthreonine-containing substrate 2MP-TbD-AFC as a highly caspase 3-selective and cell-permeable fluorescent reporter. This lead compound was converted into the radiotracer [F]-TBD, which was obtained at 10% decay-corrected yields with molar activities up to 149 GBq/μmol on an automated radiosynthesis platform. [F]-TBD accumulated in ovarian cancer cells in a caspase- and cisplatin-dependent fashion. PET imaging of a Jo2-induced hepatotoxicity model showed a significant increase in [F]-TBD signal in the livers of Jo2-treated mice compared to controls, driven through a reduction in hepatobiliary clearance. A chemical control tracer that could not be cleaved by caspase 3 showed no change in liver accumulation after induction of hepatocyte apoptosis. Our data demonstrate that [F]-TBD provides an immediate pharmacodynamic readout of liver apoptosis in mice by dynamic PET/CT and suggest that [F]-TBD could be used to interrogate apoptosis in other disease states.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.bioconjchem.8b00514DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6467260PMC
September 2018

A Coclinical Radiogenomic Validation Study: Conserved Magnetic Resonance Radiomic Appearance of Periostin-Expressing Glioblastoma in Patients and Xenograft Models.

Clin Cancer Res 2018 12 27;24(24):6288-6299. Epub 2018 Jul 27.

Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, Texas.

Purpose: Radiomics is the extraction of multidimensional imaging features, which when correlated with genomics, is termed radiogenomics. However, radiogenomic biological validation is not sufficiently described in the literature. We seek to establish causality between differential gene expression status and MRI-extracted radiomic-features in glioblastoma.

Experimental Design: Radiogenomic predictions and validation were done using the Cancer Genome Atlas and Repository of Molecular Brain Neoplasia Data glioblastoma patients ( = 93) and orthotopic xenografts (OX; = 40). Tumor phenotypes were segmented, and radiomic-features extracted using the developed radiome-sequencing pipeline. Patients and animals were dichotomized on the basis of Periostin ( expression levels. RNA and protein levels confirmed RNAi-mediated knockdown in OX. Total RNA of tumor cells isolated from mouse brains (knockdown and control) was used for microarray-based expression profiling. Radiomic-features were utilized to predict expression status in patient, mouse, and interspecies.

Results: Our robust pipeline consists of segmentation, radiomic-feature extraction, feature normalization/selection, and predictive modeling. The combination of skull stripping, brain-tissue focused normalization, and patient-specific normalization are unique to this study, providing comparable cross-platform, cross-institution radiomic features. expression status was not associated with qualitative or volumetric MRI parameters. Radiomic features significantly predicted expression status in patients (AUC: 76.56%; sensitivity/specificity: 73.91/78.26%) and OX (AUC: 92.26%; sensitivity/specificity: 92.86%/91.67%). Furthermore, radiomic features in OX were significantly associated with patients with similar expression levels (AUC: 93.36%; sensitivity/specificity: 82.61%/95.74%; = 02.021E-15).

Conclusions: We determined causality between radiomic texture features and expression levels in a preclinical model with clinical validation. Our biologically validated radiomic pipeline also showed the potential application for human-mouse matched coclinical trials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/1078-0432.CCR-17-3420DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6538261PMC
December 2018

Spatial and Temporal Confined Photothermolysis of Cancer Cells Mediated by Hollow Gold Nanospheres Targeted to Epidermal Growth Factor Receptors.

ACS Omega 2018 May;3(5):5888-5895

Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, 1881 East Road, Houston, Texas 77054, United States.

To date, a few studies have investigated the potential use of a short-pulsed laser in selective tumor cell destruction or its mechanism of cell killing. Computer simulation of the spatial and temporal profiles of temperature elevation after pulsed laser irradiation on an infinitesimal point source estimated that the temperature reached its highest point at ∼35 ns after a single 15 ns laser pulse. Moreover, temperature elevation was confined to a radius of sub-micrometer and returned to baseline within 100 ns. To investigate the effect of 15 ns laser pulses on A431 tumor cells, we conjugated hollow gold nanospheres (HAuNSs) to an antibody (C225) directed at the epithelial growth factor receptor. The resulting nanoparticles, C225-HAuNSs, bound to the cell membrane, internalized, and distributed throughout the cytoplasm, with some nanoparticles transported to the vicinity of the nuclear membrane. On using an optical microscope mounted to a tunable pulsed Ti:sapphire laser, rapid and extensive damage of live cancer cells was observed, whereas irradiation of A431 cells pretreated with nontargeted HAuNSs with a pulsed laser or pretreated with C225-HAuNSs with a continuous-wave laser-induced minimal cellular damage. Furthermore, after a single 15 ns laser pulse, C225-HAuNS-treated A431 cells cocultured with 3T3 fibroblasts showed signs of selective destruction. Thus, compared with a continuous-wave laser, shots of a short-pulsed laser were the most damaging to tumor cells that bound HAuNSs and generated the least heat to the surrounding environment. This mode of action by a short-pulsed laser on cancer cells (i.e., confined photothermolysis) may have potential applications in selective tumor cell destruction.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsomega.8b00712DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5981767PMC
May 2018

Androgen Receptor Signaling in Castration-Resistant Prostate Cancer Alters Hyperpolarized Pyruvate to Lactate Conversion and Lactate Levels In Vivo.

Mol Imaging Biol 2019 02;21(1):86-94

Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, 1881 East Road, Unit 1907, Houston, TX, 77054, USA.

Purpose: Androgen receptor (AR) signaling affects prostate cancer (PCa) growth, metabolism, and progression. Often, PCa progresses from androgen-sensitive to castration-resistant prostate cancer (CRPC) following androgen-deprivation therapy. Clinicopathologic and genomic characterizations of CRPC tumors lead to subdividing CRPC into two subtypes: (1) AR-dependent CRPC containing dysregulation of AR signaling alterations in AR such as amplification, point mutations, and/or generation of splice variants in the AR gene; and (2) an aggressive variant PCa (AVPC) subtype that is phenotypically similar to small cell prostate cancer and is defined by chemotherapy sensitivity, gain of neuroendocrine or pro-neural marker expression, loss of AR expression, and combined alterations of PTEN, TP53, and RB1 tumor suppressors. Previously, we reported patient-derived xenograft (PDX) animal models that contain characteristics of these CRPC subtypes. In this study, we have employed the PDX models to test metabolic alterations in the CRPC subtypes.

Procedures: Mass spectrometry and nuclear magnetic resonance analysis along with in vivo hyperpolarized 1-[C]pyruvate spectroscopy experiments were performed on prostate PDX animal models.

Results: Using hyperpolarized 1-[C]pyruvate conversion to 1-[C]lactate in vivo as well as lactate measurements ex vivo, we have found increased lactate production in AR-dependent CRPC PDX models even under low-hormone levels (castrated mouse) compared to AR-negative AVPC PDX models.

Conclusions: Our analysis underscores the potential of hyperpolarized metabolic imaging in determining the underlying biology and in vivo phenotyping of CRPC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11307-018-1199-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6230314PMC
February 2019

Nucleoside Diphosphate Kinase-3 () Enhances TLR5-Induced NFB Activation.

Mol Cancer Res 2018 06 9;16(6):986-999. Epub 2018 Mar 9.

Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, Texas.

Bacterial flagellin is a potent activator of NFκB signaling, inflammation, and host innate immunity, and recent data indicate that flagellin represents a novel antitumor ligand acting through toll-like receptor 5 (TLR5) and the NFκB pathway to induce host immunity and aid in the clearance of tumor xenografts. To identify innate signaling components of TLR5 responsible for these antitumor effects, a loss-of-function high-throughput screen was employed utilizing carcinoma cells expressing a dynamic NFκB bioluminescent reporter stimulated by expressing flagellin. A live cell screen of a siRNA library targeting 691 known and predicted human kinases to identify novel tumor cell modulators of TLR5-induced NFκB activation uncovered several interesting positive and negative candidate regulators not previously recognized, including nucleoside diphosphate kinase 3 (NME3), characterized as an enhancer of signaling responses to flagellin. Targeted knockdown and overexpression assays confirmed the regulatory contribution of NME3 to TLR5-mediated NFκB signaling, mechanistically downstream of MyD88. Furthermore, Kaplan-Meier survival analysis showed that NME3 expression correlated highly with TLR5 expression in breast, lung, ovarian, and gastric cancers, and furthermore, high-level expression of NME3 increased overall survival for patients with breast, lung, and ovarian cancer, but the opposite in gastric cancer. Together, these data identify a previously unrecognized proinflammatory role for NME3 in signaling downstream of TLR5 that may potentiate cancer immunotherapies. Proinflammatory signaling mediated by innate immunity engagement of flagellin-activated TLR5 in tumor cells results in antitumor effects through NME3 kinase, a positive downstream regulator of flagellin-mediated NFκB signaling, enhancing survival for several human cancers. .
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/1541-7786.MCR-17-0603DOI Listing
June 2018

Simultaneous inhibition of hedgehog signaling and tumor proliferation remodels stroma and enhances pancreatic cancer therapy.

Biomaterials 2018 03 9;159:215-228. Epub 2018 Jan 9.

Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA. Electronic address:

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers. It has an excessive desmoplastic stroma that can limit the intratumoral delivery of chemotherapy drugs, and protect tumor cells against radiotherapy. Therefore, both stromal and tumor compartments need to be addressed in order to effectively treat PDAC. We hereby co-deliver a sonic hedgehog inhibitor, cyclopamine (CPA), and a cytotoxic chemotherapy drug paclitaxel (PTX) with a polymeric micelle formulation (M-CPA/PTX). CPA can deplete the stroma-producing cancer-associated fibroblasts (CAFs), while PTX can inhibit tumor proliferation. Here we show that in clinically relevant PDAC models, M-CPA effectively modulates stroma by increasing microvessel density, alleviating hypoxia, reducing matrix stiffness while maintaining the tumor-restraining function of extracellular matrix. M-CPA/PTX also significantly extends animal survival by suppressing tumor growth and lowering the percentages of poorly to moderately differentiated tumor phenotypes. Our study suggests that using multifunctional nanoparticles to simultaneously target stromal and tumor compartments is a promising strategy for PDAC therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biomaterials.2018.01.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6203960PMC
March 2018

p38 MAPK inhibits nonsense-mediated RNA decay in response to persistent DNA damage in noncycling cells.

J Biol Chem 2017 09 1;292(37):15266-15276. Epub 2017 Aug 1.

From the Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110 and

Persistent DNA damage induces profound alterations in gene expression that, in turn, influence tissue homeostasis, tumorigenesis, and cancer treatment outcome. However, the underlying mechanism for gene expression reprogramming induced by persistent DNA damage remains poorly understood. Here, using a highly effective bioluminescence-based reporter system and other tools, we report that persistent DNA damage inhibits nonsense-mediated RNA decay (NMD), an RNA surveillance and gene-regulatory pathway, in noncycling cells. NMD suppression by persistent DNA damage required the activity of the p38α MAPK. Activating transcription factor 3 (ATF3), an NMD target and a key stress-inducible transcription factor, was stabilized in a p38α- and NMD-dependent manner following persistent DNA damage. Our results reveal a novel p38α-dependent pathway that regulates NMD activity in response to persistent DNA damage, which, in turn, controls ATF3 expression in affected cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.M117.787846DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5602387PMC
September 2017

Automated, Resin-Based Method to Enhance the Specific Activity of Fluorine-18 Clicked PET Radiotracers.

Bioconjug Chem 2017 02 2;28(2):583-589. Epub 2017 Feb 2.

EvoRx Technologies , 129 North Hill Avenue, Suite 103 Pasadena, California 91106, United States.

Radiolabeling of substrates with 2-[F]fluoroethylazide exploits the rapid kinetics, chemical selectivity, and mild conditions of the copper-catalyzed azide-alkyne cycloaddition reaction. While this methodology has proven to result in near-quantitative labeling of alkyne-tagged precursors, the relatively small size of the fluoroethylazide group makes separation of the F-labeled radiotracer and the unreacted precursor challenging, particularly with precursors >500 Da (e.g., peptides). We have developed an inexpensive azide-functionalized resin to rapidly remove unreacted alkyne precursor following the fluoroethylazide labeling reaction and integrated it into a fully automated radiosynthesis platform. We have carried out 2-[F]fluoroethylazide labeling of four different alkynes ranging from <300 Da to >1700 Da and found that >98% of the unreacted alkyne was removed in less than 20 min at room temperature to afford the final radiotracers at >99% radiochemical purity with specific activities up to >200 GBq/μmol. We have applied this technique to label a novel cyclic peptide previously evolved to bind the Her2 receptor with high affinity, and demonstrated tumor-specific uptake and low nonspecific background by PET/CT. This resin-based methodology is automated, rapid, mild, and general allowing peptide-based fluorine-18 radiotracers to be obtained with clinically relevant specific activities without chromatographic separation and with only a minimal increase in total synthesis time.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.bioconjchem.6b00678DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6463876PMC
February 2017
-->