Publications by authors named "Yaroslav Teper"

12 Publications

  • Page 1 of 1

T Cell-Mediated Antitumor Immunity Cooperatively Induced By TGFβR1 Antagonism and Gemcitabine Counteracts Reformation of the Stromal Barrier in Pancreatic Cancer.

Mol Cancer Ther 2021 Aug 10. Epub 2021 Aug 10.

Rare Tumor Initiative, Pediatric Oncology Branch, Center for Cancer Research, NCI, Bethesda, Maryland.

The desmoplastic stroma of pancreatic cancers forms a physical barrier that impedes intratumoral drug delivery. Attempts to modulate the desmoplastic stroma to increase delivery of administered chemotherapy have not shown positive clinical results thus far, and preclinical reports in which chemotherapeutic drugs were coadministered with antistromal therapies did not universally demonstrate increased genotoxicity despite increased intratumoral drug levels. In this study, we tested whether TGFβ antagonism can break the stromal barrier, enhance perfusion and tumoral drug delivery, and interrogated cellular and molecular mechanisms by which the tumor prevents synergism with coadministered gemcitabine. TGFβ inhibition in genetically engineered murine models (GEMM) of pancreas cancer enhanced tumoral perfusion and increased intratumoral gemcitabine levels. However, tumors rapidly adapted to TGFβ-dependent stromal modulation, and intratumoral perfusion returned to pre-treatment levels upon extended TGFβ inhibition. Perfusion was governed by the phenotypic identity and distribution of cancer-associated fibroblasts (CAF) with the myelofibroblastic phenotype (myCAFs), and myCAFs which harbored unique genomic signatures rapidly escaped the restricting effects of TGFβ inhibition. Despite the reformation of the stromal barrier and reversal of initially increased intratumoral exposure levels, TGFβ inhibition in cooperation with gemcitabine effectively suppressed tumor growth via cooperative reprogramming of T regulatory cells and stimulation of CD8 T cell-mediated antitumor activity. The antitumor activity was further improved by the addition of anti-PD-L1 immune checkpoint blockade to offset adaptive PD-L1 upregulation induced by TGFβ inhibition. These findings support the development of combined antistroma anticancer therapies capable of impacting the tumor beyond the disruption of the desmoplastic stroma as a physical barrier to improve drug delivery.
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http://dx.doi.org/10.1158/1535-7163.MCT-20-0620DOI Listing
August 2021

Direct Effects of Lipopolysaccharide on Human Pancreatic Cancer Cells.

Pancreas 2021 04;50(4):524-528

From the Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA.

Objectives: Obesity, a risk factor for pancreatic adenocarcinoma (PDAC), is often accompanied by a systemic increase in lipopolysaccharide (LPS; metabolic endotoxemia), which is thought to mediate obesity-associated inflammation. However, the direct effects of LPS on PDAC cells are poorly understood.

Methods: The expression of toll-like receptor 4, the receptor for LPS, was confirmed in PDAC cell lines. AsPC-1 and PANC-1 cells were exposed to LPS, and differential gene expression was determined by RNA sequencing. The activation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway by LPS in PDAC cells was assessed by Western blotting.

Results: The expression of toll-like receptor 4 was confirmed in all PDAC cell lines. The exposure to LPS led to differential expression of 3083 genes (426 ≥5-fold) in AsPC-1 and 2584 genes (339 ≥5-fold) in PANC-1. A top canonical pathway affected by LPS in both cell lines was PI3K/Akt/mTOR. Western blotting confirmed activation of this pathway as measured by phosphorylation of the ribosomal protein S6 and Akt.

Conclusions: The exposure of PDAC cells to LPS led to differential gene expression. A top canonical pathway was PI3K/Akt/mTOR, a known oncogenic driver. Our findings provided evidence that LPS can directly induce differential gene expression in PDAC cells.
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http://dx.doi.org/10.1097/MPA.0000000000001790DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8097724PMC
April 2021

Pancreatic Macrophages: Critical Players in Obesity-Promoted Pancreatic Cancer.

Cancers (Basel) 2020 Jul 17;12(7). Epub 2020 Jul 17.

Department of Surgery, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA 90095, USA.

Obesity is a known risk factor for the development of pancreatic cancer, one of the deadliest types of malignancies. In recent years it has become clear that the pancreatic microenvironment is critically involved and a contributing factor in accelerating pancreatic neoplasia. In this context obesity-associated chronic inflammation plays an important role. Among several immune cells, macrophages have been shown to contribute to obesity-induced tissue inflammation. This review article summarizes the current knowledge about the role of pancreatic macrophages in early pancreatic cancer development. It describes the heterogenous origin and mixture of pancreatic macrophages, their role in pancreatic endocrine and exocrine pathology, and the impact of obesity on islet and stromal macrophages. A model is postulated, by which during obesity monocytes are recruited into the pancreas, where they are polarized into pro-inflammatory macrophages that drive early pancreatic neoplasia. This occurs in the presence of local inflammatory, metabolic, and endocrine signals. A stronger appreciation and more detailed knowledge about the role of macrophages in early pancreatic cancer development will lead to innovative preventive or interceptive strategies.
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http://dx.doi.org/10.3390/cancers12071946DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7409049PMC
July 2020

Target Deconvolution of a Multikinase Inhibitor with Antimetastatic Properties Identifies TAOK3 as a Key Contributor to a Cancer Stem Cell-Like Phenotype.

Mol Cancer Ther 2019 11 8;18(11):2097-2110. Epub 2019 Aug 8.

Rare Tumor Initiative, Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland.

Pancreatic cancer remains an incurable condition. Its progression is driven, in part, by subsets of cancer cells that evade the cytotoxic effects of conventional chemotherapies. These cells are often low-cycling, multidrug resistant, and adopt a stem cell-like phenotype consistent with the concept of cancer stem cells (CSC). To identify drugs impacting on tumor-promoting CSCs, we performed a differential high-throughput drug screen in pancreatic cancer cells cultured in traditional (2D) monolayers versus three-dimensional (3D) spheroids which replicate key elements of the CSC model. Among the agents capable of killing cells cultured in both formats was a 1H-benzo[d]imidazol-2-amine-based inhibitor of IL2-inducible T-cell kinase (ITK; NCGC00188382, inhibitor #1) that effectively mediated growth inhibition and induction of apoptosis , and suppressed cancer progression and metastasis formation An examination of this agent's polypharmacology via and phosphoproteomic profiling demonstrated an activity profile enriched for mediators involved in DNA damage repair. Included was a strong inhibitory potential versus the thousand-and-one amino acid kinase 3 (TAOK3), CDK7, and aurora B kinases. We found that cells grown under CSC-enriching spheroid conditions are selectively dependent on TAOK3 signaling. Loss of TAOK3 decreases colony formation, expression of stem cell markers, and sensitizes spheroids to the genotoxic effect of gemcitabine, whereas overexpression of TAOK3 increases stem cell traits including tumor initiation and metastasis formation. By inactivating multiple components of the cell-cycle machinery in concert with the downregulation of key CSC signatures, inhibitor #1 defines a distinctive strategy for targeting pancreatic cancer cell populations.
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http://dx.doi.org/10.1158/1535-7163.MCT-18-1011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6825557PMC
November 2019

Metarrestin, a perinucleolar compartment inhibitor, effectively suppresses metastasis.

Sci Transl Med 2018 05;10(441)

Department of Cell and Molecular Biology, Northwestern University, Chicago, IL 60611, USA.

Metastasis remains a leading cause of cancer mortality due to the lack of specific inhibitors against this complex process. To identify compounds selectively targeting the metastatic state, we used the perinucleolar compartment (PNC), a complex nuclear structure associated with metastatic behaviors of cancer cells, as a phenotypic marker for a high-content screen of over 140,000 structurally diverse compounds. Metarrestin, obtained through optimization of a screening hit, disassembles PNCs in multiple cancer cell lines, inhibits invasion in vitro, suppresses metastatic development in three mouse models of human cancer, and extends survival of mice in a metastatic pancreatic cancer xenograft model with no organ toxicity or discernable adverse effects. Metarrestin disrupts the nucleolar structure and inhibits RNA polymerase (Pol) I transcription, at least in part by interacting with the translation elongation factor eEF1A2. Thus, metarrestin represents a potential therapeutic approach for the treatment of metastatic cancer.
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http://dx.doi.org/10.1126/scitranslmed.aap8307DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6176865PMC
May 2018

Whole Genome Sequencing of Newly Established Pancreatic Cancer Lines Identifies Novel Somatic Mutation (c.2587G>A) in Axon Guidance Receptor Plexin A1 as Enhancer of Proliferation and Invasion.

PLoS One 2016 10;11(3):e0149833. Epub 2016 Mar 10.

Thoracic & GI Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20892, United States of America.

The genetic profile of human pancreatic cancers harbors considerable heterogeneity, which suggests a possible explanation for the pronounced inefficacy of single therapies in this disease. This observation has led to a belief that custom therapies based on individual tumor profiles are necessary to more effectively treat pancreatic cancer. It has recently been discovered that axon guidance genes are affected by somatic structural variants in up to 25% of human pancreatic cancers. Thus far, however, some of these mutations have only been correlated to survival probability and no function has been assigned to these observed axon guidance gene mutations in pancreatic cancer. In this study we established three novel pancreatic cancer cell lines and performed whole genome sequencing to discover novel mutations in axon guidance genes that may contribute to the cancer phenotype of these cells. We discovered, among other novel somatic variants in axon guidance pathway genes, a novel mutation in the PLXNA1 receptor (c.2587G>A) in newly established cell line SB.06 that mediates oncogenic cues of increased invasion and proliferation in SB.06 cells and increased invasion in 293T cells upon stimulation with the receptor's natural ligand semaphorin 3A compared to wild type PLXNA1 cells. Mutant PLXNA1 signaling was associated with increased Rho-GTPase and p42/p44 MAPK signaling activity and cytoskeletal expansion, but not changes in E-cadherin, vimentin, or metalloproteinase 9 expression levels. Pharmacologic inhibition of the Rho-GTPase family member CDC42 selectively abrogated PLXNA1 c.2587G>A-mediated increased invasion. These findings provide in-vitro confirmation that somatic mutations in axon guidance genes can provide oncogenic gain-of-function signals and may contribute to pancreatic cancer progression.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0149833PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4786220PMC
July 2016

A novel chimeric antigen receptor against prostate stem cell antigen mediates tumor destruction in a humanized mouse model of pancreatic cancer.

Hum Gene Ther 2014 Dec;25(12):1003-12

Surgery Branch, National Cancer Institute , National Institutes of Health, Bethesda, MD 20892.

Despite advances in the understanding of its molecular pathophysiology, pancreatic cancer remains largely incurable, highlighting the need for novel therapies. We developed a chimeric antigen receptor (CAR) specific for prostate stem cell antigen (PSCA), a glycoprotein that is overexpressed in pancreatic cancer starting at early stages of malignant transformation. To optimize the CAR design, we used antigen-recognition domains derived from mouse or human antibodies, and intracellular signaling domains containing one or two T cell costimulatory elements, in addition to CD3zeta. Comparing multiple constructs established that the CAR based on human monoclonal antibody Ha1-4.117 had the greatest reactivity in vitro. To further analyze this CAR, we developed a human pancreatic cancer xenograft model and adoptively transferred CAR-engineered T cells into animals with established tumors. CAR-engineered human lymphocytes induced significant antitumor activity, and unlike what has been described for other CARs, a second-generation CAR (containing CD28 cosignaling domain) induced a more potent antitumor effect than a third-generation CAR (containing CD28 and 41BB cosignaling domains). While our results provide evidence to support PSCA as a target antigen for CAR-based immunotherapy of pancreatic cancer, the expression of PSCA on selected normal tissues could be a source of limiting toxicity.
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http://dx.doi.org/10.1089/hum.2013.209DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4270113PMC
December 2014

Fatty acid binding protein 4 is a target of VEGF and a regulator of cell proliferation in endothelial cells.

FASEB J 2009 Nov 22;23(11):3865-73. Epub 2009 Jul 22.

Division of Newborn Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02115, USA.

Fatty acid binding protein 4 (FABP4) plays an important role in maintaining glucose and lipid homeostasis. FABP4 has been primarily regarded as an adipocyte- and macrophage-specific protein, but recent studies suggest that it may be more widely expressed. We found strong FABP4 expression in the endothelial cells (ECs) of capillaries and small veins in several mouse and human tissues, including the heart and kidney. FABP4 was also detected in the ECs of mature human placental vessels and infantile hemangiomas, the most common tumor of infancy and ECs. In most of these cases, FABP4 was detected in both the nucleus and cytoplasm. FABP4 mRNA and protein levels were significantly induced in cultured ECs by VEGF-A and bFGF treatment. The effect of VEGF-A on FABP4 expression was inhibited by chemical inhibition or short-hairpin (sh) RNA-mediated knockdown of VEGF-receptor-2 (R2), whereas the VEGFR1 agonists, placental growth factors 1 and 2, had no effect on FABP4 expression. Knockdown of FABP4 in ECs significantly reduced proliferation both under baseline conditions and in response to VEGF and bFGF. Thus, FABP4 emerged as a novel target of the VEGF/VEGFR2 pathway and a positive regulator of cell proliferation in ECs.
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http://dx.doi.org/10.1096/fj.09-134882DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2775007PMC
November 2009

Altered fast- and slow-twitch muscle fibre characteristics in female mice with a (S248F) knock-in mutation of the brain neuronal nicotinic acetylcholine receptor.

J Muscle Res Cell Motil 2009 29;30(1-2):73-83. Epub 2009 Apr 29.

School of Life and Environmental Sciences, Deakin University, VIC, Australia.

We generated a mouse line with a missense mutation (S248F) in the gene (CHRNA4) encoding the alpha4 subunit of neuronal nicotinic acetylcholine receptor (nAChR). Mutant mice demonstrate brief nicotine induced dystonia that resembles the clinical events seen in patients with the same mutation. Drug-induced dystonia is more pronounced in female mice, thus our aim was to determine if the S248F mutation changed the properties of fast- and slow-twitch muscle fibres from female mutant mice. Reverse transcriptase-PCR confirmed CHRNA4 gene expression in the brain but not skeletal muscles in normal and mutant mice. Ca(2+) and Sr(2+) force activation curves were obtained using skinned muscle fibres prepared from slow-twitch (soleus) and fast-twitch (EDL) muscles. Two significant results were found: (1) the (pCa(50) - pSr(50)) value from EDL fibres was smaller in mutant mice than in wild type (1.01 vs. 1.30), (2) the percentage force produced at pSr 5.5 was larger in mutants than in wild type (5.76 vs. 0.24%). Both results indicate a shift to slow-twitch characteristics in the mutant. This conclusion is supported by the identification of the myosin heavy chain (MHC) isoforms. Mutant EDL fibres expressed MHC I (usually only found in slow-twitch fibres) as well as MHC IIa. Despite the lack of spontaneous dystonic events, our findings suggest that mutant mice may be having subclinical events or the mutation results in a chronic alteration to muscle neural input.
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http://dx.doi.org/10.1007/s10974-009-9177-xDOI Listing
July 2009

Nicotine-induced dystonic arousal complex in a mouse line harboring a human autosomal-dominant nocturnal frontal lobe epilepsy mutation.

J Neurosci 2007 Sep;27(38):10128-42

Howard Florey Institute, The University of Melbourne, Victoria 3010, Australia.

We generated a mouse line harboring an autosomal-dominant nocturnal frontal lobe epilepsy (ADNFLE) mutation: the alpha4 nicotinic receptor S248F knock-in strain. In this mouse, modest nicotine doses (1-2 mg/kg) elicit a novel behavior termed the dystonic arousal complex (DAC). The DAC includes stereotypical head movements, body jerking, and forelimb dystonia; these behaviors resemble some core features of ADNFLE. A marked Straub tail is an additional component of the DAC. Similar to attacks in ADNFLE, the DAC can be partially suppressed by the sodium channel blocker carbamazepine or by pre-exposure to a very low dose of nicotine (0.1 mg/kg). The DAC is centrally mediated, genetically highly penetrant, and, surprisingly, not associated with overt ictal electrical activity as assessed by (1) epidural or frontal lobe depth-electrode electroencephalography or (2) hippocampal c-fos-regulated gene expression. Heterozygous knock-in mice are partially protected from nicotine-induced seizures. The noncompetitive antagonist mecamylamine does not suppress the DAC, although it suppresses high-dose nicotine-induced wild-type-like seizures. Experiments on agonist-induced 86Rb+ and neurotransmitter efflux from synaptosomes and on alpha4S248Fbeta2 receptors expressed in oocytes confirm that the S248F mutation confers resistance to mecamylamine blockade. Genetic background, gender, and mutant gene expression levels modulate expression of the DAC phenotype in mice. The S248F mouse thus appears to provide a model for the paroxysmal dystonic element of ADNFLE semiology. Our model complements what is seen in other ADNFLE animal models. Together, these mice cover the spectrum of behavioral and electrographic events seen in the human condition.
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http://dx.doi.org/10.1523/JNEUROSCI.3042-07.2007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6672658PMC
September 2007

Ablation of D1 dopamine receptor-expressing cells generates mice with seizures, dystonia, hyperactivity, and impaired oral behavior.

Proc Natl Acad Sci U S A 2007 Mar 28;104(10):4182-7. Epub 2007 Feb 28.

Howard Florey Institute, University of Melbourne, Melbourne 3010, Australia.

Huntington's disease is characterized by death of striatal projection neurons. We used a Cre/Lox transgenic approach to generate an animal model in which D1 dopamine receptor (Drd1a)+ cells are progressively ablated in the postnatal brain. Striatal Drd1a, substance P, and dynorphin expression is progressively lost, whereas D2 dopamine receptor (Drd2) and enkephalin expression is up-regulated. Magnetic resonance spectroscopic analysis demonstrated early elevation of the striatal choline/creatine ratio, a finding associated with extensive reactive striatal astrogliosis. Sequential MRI demonstrated a progressive reduction in striatal volume and secondary ventricular enlargement confirmed to be due to loss of striatal cells. Mutant mice had normal gait and rotarod performance but displayed hindlimb dystonia, locomotor hyperactivity, and handling-induced electrographically verified spontaneous seizures. Ethological assessment identified an increase in rearing and impairments in the oral behaviors of sifting and chewing. In line with the limbic seizure profile, cell loss, astrogliosis, microgliosis, and down-regulated dynorphin expression were seen in the hippocampal dentate gyrus. This study specifically implicates Drd1a+ cell loss with tail suspension hindlimb dystonia, hyperactivity, and abnormal oral function. The latter may relate to the speech and swallowing disturbances and the classic sign of tongue-protrusion motor impersistence observed in Huntington's disease. In addition, the findings of this study support the notion that Drd1a and Drd2 are segregated on striatal projection neurons.
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http://dx.doi.org/10.1073/pnas.0611625104DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1820729PMC
March 2007

Murine embryonic EGF-responsive ventral mesencephalic neurospheres display distinct regional specification and promote survival of dopaminergic neurons.

Exp Neurol 2006 May 19;199(1):209-21. Epub 2006 Apr 19.

Howard Florey Institute of Experimental Physiology and Medicine, The University of Melbourne, Victoria 3010, Australia.

Similar to embryonic forebrain, the embryonic mesencephalon contains Fibroblast Growth Factor 2 (FGF2)- and Epidermal Growth Factor (EGF)-responsive progenitors that can be isolated as neurospheres. Developmentally, the FGF2-responsive population appears first and is thought to give rise to EGF-responsive neural stem cells. It is not known whether following this developmental switch of growth factor responsiveness ventral mesencephalic (VM)-derived neural stem cells display distinct region-specific properties. We found that murine VM- and dorsal mesencephalic (DM)-derived primary neurospheres isolated with EGF at embryonic day 14.5 differed with respect to neurosphere formation efficacy and size. VM- but not DM-derived spheres expressed En1, the molecular marker of isthmic organizer, and contained transcripts of BDNF, FGF2, IGF-I and NT-3. Both VM and DM primary neurospheres were self-renewing and gave rise to astroglial cells, but 20% of VM spheres also generated neurons. According to in vitro properties, DM- and majority of VM-derived EGF-responsive progenitors represent glial precursors. VM- but not DM-derived primary neurospheres enriched their respective conditioned medium with factors that promoted the survival of dopaminergic neurons in vitro, suggesting that ventral mesencephalic EGF-responsive progenitors are endowed with the potential to provide trophic support to nearby nascent dopaminergic neurons. These data may have implications in the treatment of Parkinson's disease.
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http://dx.doi.org/10.1016/j.expneurol.2006.02.120DOI Listing
May 2006
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