Publications by authors named "Suhasini Joshi"

23 Publications

  • Page 1 of 1

Structurally symmetric near-infrared fluorophore IRDye78-protein complex enables multimodal cancer imaging.

Theranostics 2021 1;11(6):2534-2549. Epub 2021 Jan 1.

School of Chemistry and Materials Science, Rochester Institute of Technology, Rochester 14623, NY, USA.

Most contemporary cancer therapeutic paradigms involve initial imaging as a treatment roadmap, followed by the active engagement of surgical operations. Current approved intraoperative contrast agents exemplified by indocyanine green (ICG) have a few drawbacks including the inability of pre-surgical localization. Alternative near-infrared (NIR) dyes including IRDye800cw are being explored in advanced clinical trials but often encounter low chemical yields and complex purifications owing to the asymmetric synthesis. A single contrast agent with ease of synthesis that works in multiple cancer types and simultaneously allows presurgical imaging, intraoperative deep-tissue three-dimensional visualization, and high-speed microscopic visualization of tumor margins spatiotemporally complementary modalities would be beneficial. Due to the lack of commercial availability and the absence of detailed synthesis and characterization, we proposed a facile and scalable synthesis pathway for the symmetric NIR water-soluble heptamethine sulfoindocyanine IRDye78. The synthesis can be accomplished in four steps from commercially-available building blocks. Its symmetric resonant structure avoided asymmetric synthesis problems while still preserving the benefits of analogous IRDye800cw with commensurable optical properties. Next, we introduced a low-molecular-weight protein alpha-lactalbumin (α-LA) as the carrier that effectively modulates the hepatic clearance of IRDye78 into the preferred renal excretion pathway. We further implemented Zr radiolabeling onto the protein scaffold for positron emission tomography (PET). The multimodal imaging capability of the fluorophore-protein complex was validated in breast cancer and glioblastoma. The scalable synthesis resulted in high chemical yields, typically 95% yield in the final step of the chloro dye. Chemical structures of intermediates and the final fluorophore were confirmed. Asymmetric IRDye78 exhibited comparable optical features as symmetric IRDye800cw. Its well-balanced quantum yield affords concurrent dual fluorescence and optoacoustic contrast without self-quenching nor concentration-dependent absorption. The NHS ester functionality modulates efficient covalent coupling to reactive side-chain amines to the protein carrier, along with desferrioxamine (DFO) for stable radiolabeling of Zr. The fluorophore-protein complex advantageously shifted the biodistribution and can be effectively cleared through the urinary pathway. The agent accumulates in tumors and enables triple-modal visualization in mouse xenograft models of both breast and brain cancers. This study described in detail a generalized strategic modulation of clearance routes towards the favorable renal clearance, the introduction of α-LA. IRDye78 as a feasible alternative of IRDye800cw currently in clinical phases was proposed with a facile synthesis and fully characterized for the first time. This fluorophore-protein complex with stable radiolabeling should have great potential for clinical translation where it could enable an elegant workflow from preoperative planning to intraoperative deep tissue and high-resolution image-guided resection.
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http://dx.doi.org/10.7150/thno.54928DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7806473PMC
January 2021

Unbiased in vivo preclinical evaluation of anticancer drugs identifies effective therapy for the treatment of pancreatic adenocarcinoma.

Proc Natl Acad Sci U S A 2020 12 16;117(48):30670-30678. Epub 2020 Nov 16.

David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065;

Pancreatic ductal adenocarcinoma (PDAC) is typically diagnosed at an advanced stage, which limits surgical options and portends a dismal prognosis. Current oncologic PDAC therapies confer marginal benefit and, thus, a significant unmet clinical need exists for new therapeutic strategies. To identify effective PDAC therapies, we leveraged a syngeneic orthotopic PDAC transplant mouse model to perform a large-scale, in vivo screen of 16 single-agent and 41 two-drug targeted therapy combinations in mice. Among 57 drug conditions screened, combined inhibition of heat shock protein (Hsp)-90 and MEK was found to produce robust suppression of tumor growth, leading to an 80% increase in the survival of PDAC-bearing mice with no significant toxicity. Mechanistically, we observed that single-agent MEK inhibition led to compensatory activation of resistance pathways, including components of the PI3K/AKT/mTOR signaling axis, which was overcome with the addition of HSP90 inhibition. The combination of HSP90(i) + MEK(i) was also active in vitro in established human PDAC cell lines and in vivo in patient-derived organoid PDAC transplant models. These findings encourage the clinical development of HSP90(i) + MEK(i) combination therapy and highlight the power of clinically relevant in vivo model systems for identifying cancer therapies.
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http://dx.doi.org/10.1073/pnas.1920240117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7720119PMC
December 2020

Gold/alpha-lactalbumin nanoprobes for the imaging and treatment of breast cancer.

Nat Biomed Eng 2020 07 13;4(7):686-703. Epub 2020 Jul 13.

Center for Molecular Imaging and Nanotechnology (CMINT), Memorial Sloan Kettering Cancer Center, New York, NY, USA.

Theranostic agents should ideally be renally cleared and biodegradable. Here, we report the synthesis, characterization and theranostic applications of fluorescent ultrasmall gold quantum clusters that are stabilized by the milk metalloprotein alpha-lactalbumin. We synthesized three types of these nanoprobes that together display fluorescence across the visible and near-infrared spectra when excited at a single wavelength through optical colour coding. In live tumour-bearing mice, the near-infrared nanoprobe generates contrast for fluorescence, X-ray computed tomography and magnetic resonance imaging, and exhibits long circulation times, low accumulation in the reticuloendothelial system, sustained tumour retention, insignificant toxicity and renal clearance. An intravenously administrated near-infrared nanoprobe with a large Stokes shift facilitated the detection and image-guided resection of breast tumours in vivo using a smartphone with modified optics. Moreover, the partially unfolded structure of alpha-lactalbumin in the nanoprobe helps with the formation of an anti-cancer lipoprotein complex with oleic acid that triggers the inhibition of the MAPK and PI3K-AKT pathways, immunogenic cell death and the recruitment of infiltrating macrophages. The biodegradability and safety profile of the nanoprobes make them suitable for the systemic detection and localized treatment of cancer.
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http://dx.doi.org/10.1038/s41551-020-0584-zDOI Listing
July 2020

Molecular Stressors Engender Protein Connectivity Dysfunction through Aberrant N-Glycosylation of a Chaperone.

Cell Rep 2020 06;31(13):107840

Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA. Electronic address:

Stresses associated with disease may pathologically remodel the proteome by both increasing interaction strength and altering interaction partners, resulting in proteome-wide connectivity dysfunctions. Chaperones play an important role in these alterations, but how these changes are executed remains largely unknown. Our study unveils a specific N-glycosylation pattern used by a chaperone, Glucose-regulated protein 94 (GRP94), to alter its conformational fitness and stabilize a state most permissive for stable interactions with proteins at the plasma membrane. This "protein assembly mutation' remodels protein networks and properties of the cell. We show in cells, human specimens, and mouse xenografts that proteome connectivity is restorable by inhibition of the N-glycosylated GRP94 variant. In summary, we provide biochemical evidence for stressor-induced chaperone-mediated protein mis-assemblies and demonstrate how these alterations are actionable in disease.
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http://dx.doi.org/10.1016/j.celrep.2020.107840DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7372946PMC
June 2020

Chemical probes and methods for single-cell detection and quantification of epichaperomes in hematologic malignancies.

Methods Enzymol 2020 10;639:289-311. Epub 2020 May 10.

Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, United States; Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, United States. Electronic address:

Detection of protein connectivity dysfunctions in biological samples, i.e., informing on how protein-protein interactions change from a normal to a disease state, is important for both biomedical research and clinical development. The epichaperome is an executor of protein connectivity dysfunction in disease, and thus a surrogate for its detection. This chapter will detail on published methods for epichaperome detection and quantification that combine the advantages of multiparameter flow cytometry with those of the PU-FITC fluorescently labeled epichaperome detection probe. It will offer a comprehensive method description that includes the synthesis and characterization of an epichaperome detection probe and of the negative control probe, the preparation of the biospecimen for epichaperome analysis, the execution of the epichaperome detection and quantification assay and lastly, the data acquisition and analysis. The method provides, at single-cell level, the functional signature of cells, differentiating itself from other single-cell methods that provide a catalog of molecules.
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http://dx.doi.org/10.1016/bs.mie.2020.04.057DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7397528PMC
May 2020

The epichaperome is a mediator of toxic hippocampal stress and leads to protein connectivity-based dysfunction.

Nat Commun 2020 01 16;11(1):319. Epub 2020 Jan 16.

Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA.

Optimal functioning of neuronal networks is critical to the complex cognitive processes of memory and executive function that deteriorate in Alzheimer's disease (AD). Here we use cellular and animal models as well as human biospecimens to show that AD-related stressors mediate global disturbances in dynamic intra- and inter-neuronal networks through pathologic rewiring of the chaperome system into epichaperomes. These structures provide the backbone upon which proteome-wide connectivity, and in turn, protein networks become disturbed and ultimately dysfunctional. We introduce the term protein connectivity-based dysfunction (PCBD) to define this mechanism. Among most sensitive to PCBD are pathways with key roles in synaptic plasticity. We show at cellular and target organ levels that network connectivity and functional imbalances revert to normal levels upon epichaperome inhibition. In conclusion, we provide proof-of-principle to propose AD is a PCBDopathy, a disease of proteome-wide connectivity defects mediated by maladaptive epichaperomes.
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http://dx.doi.org/10.1038/s41467-019-14082-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6965647PMC
January 2020

Paradigms for Precision Medicine in Epichaperome Cancer Therapy.

Cancer Cell 2019 11 24;36(5):559-573.e7. Epub 2019 Oct 24.

Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Program in Molecular Pharmacology, Sloan Kettering Institute, New York, NY 10065, USA.

Alterations in protein-protein interaction networks are at the core of malignant transformation but have yet to be translated into appropriate diagnostic tools. We make use of the kinetic selectivity properties of an imaging probe to visualize and measure the epichaperome, a pathologic protein-protein interaction network. We are able to assay and image epichaperome networks in cancer and their engagement by inhibitor in patients' tumors at single-lesion resolution in real time, and demonstrate that quantitative evaluation at the level of individual tumors can be used to optimize dose and schedule selection. We thus provide preclinical and clinical evidence in the use of this theranostic platform for precision medicine targeting of the aberrant properties of protein networks.
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http://dx.doi.org/10.1016/j.ccell.2019.09.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6996250PMC
November 2019

A Chemical Biology Approach to the Chaperome in Cancer-HSP90 and Beyond.

Cold Spring Harb Perspect Biol 2020 04 1;12(4). Epub 2020 Apr 1.

Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065.

Cancer is often associated with alterations in the chaperome, a collection of chaperones, cochaperones, and other cofactors. Changes in the expression levels of components of the chaperome, in the interaction strength among chaperome components, alterations in chaperome constituency, and in the cellular location of chaperome members, are all hallmarks of cancer. Here we aim to provide an overview on how chemical biology has played a role in deciphering such complexity in the biology of the chaperome in cancer and in other diseases. The focus here is narrow and on pathologic changes in the chaperome executed by enhancing the interaction strength between components of distinct chaperome pathways, specifically between those of HSP90 and HSP70 pathways. We will review chemical tools and chemical probe-based assays, with a focus on HSP90. We will discuss how kinetic binding, not classical equilibrium binding, is most appropriate in the development of drugs and probes for the chaperome in disease. We will then present our view on how chaperome inhibitors may become potential drugs and diagnostics in cancer.
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http://dx.doi.org/10.1101/cshperspect.a034116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6773535PMC
April 2020

HSP90-incorporating chaperome networks as biosensor for disease-related pathways in patient-specific midbrain dopamine neurons.

Nat Commun 2018 10 19;9(1):4345. Epub 2018 Oct 19.

The Center for Stem Cell Biology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 256, New York, NY, 10065, USA.

Environmental and genetic risk factors contribute to Parkinson's Disease (PD) pathogenesis and the associated midbrain dopamine (mDA) neuron loss. Here, we identify early PD pathogenic events by developing methodology that utilizes recent innovations in human pluripotent stem cells (hPSC) and chemical sensors of HSP90-incorporating chaperome networks. We show that events triggered by PD-related genetic or toxic stimuli alter the neuronal proteome, thereby altering the stress-specific chaperome networks, which produce changes detected by chemical sensors. Through this method we identify STAT3 and NF-κB signaling activation as examples of genetic stress, and phospho-tyrosine hydroxylase (TH) activation as an example of toxic stress-induced pathways in PD neurons. Importantly, pharmacological inhibition of the stress chaperome network reversed abnormal phospho-STAT3 signaling and phospho-TH-related dopamine levels and rescued PD neuron viability. The use of chemical sensors of chaperome networks on hPSC-derived lineages may present a general strategy to identify molecular events associated with neurodegenerative diseases.
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http://dx.doi.org/10.1038/s41467-018-06486-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6195591PMC
October 2018

Adapting to stress - chaperome networks in cancer.

Nat Rev Cancer 2018 09;18(9):562-575

Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.

In this Opinion article, we aim to address how cells adapt to stress and the repercussions chronic stress has on cellular function. We consider acute and chronic stress-induced changes at the cellular level, with a focus on a regulator of cellular stress, the chaperome, which is a protein assembly that encompasses molecular chaperones, co-chaperones and other co-factors. We discuss how the chaperome takes on distinct functions under conditions of stress that are executed in ways that differ from the one-on-one cyclic, dynamic functions exhibited by distinct molecular chaperones. We argue that through the formation of multimeric stable chaperome complexes, a state of chaperome hyperconnectivity, or networking, is gained. The role of these chaperome networks is to act as multimolecular scaffolds, a particularly important function in cancer, where they increase the efficacy and functional diversity of several cellular processes. We predict that these concepts will change how we develop and implement drugs targeting the chaperome to treat cancer.
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http://dx.doi.org/10.1038/s41568-018-0020-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6108944PMC
September 2018

Proteomic interrogation of HSP90 and insights for medical research.

Expert Rev Proteomics 2017 12 16;14(12):1105-1117. Epub 2017 Oct 16.

a Center for Integrative Genomics , University of Lausanne , Lausanne , Switzerland.

Introduction: Heat shock protein 90 (HSP90) regulates protein homeostasis in eukaryotes. As a 'professional interactor', HSP90 binds to and chaperones many proteins and has both housekeeping and disease-related functions but its regulation remains in part elusive. HSP90 complexes are a target for therapy, notably against cancer, and several inhibitors are currently in clinical trials. Proteomic studies have revealed the vast interaction network of HSP90 and, in doing so, the extent of cellular processes the chaperone takes part in, especially in yeast and human cells. Furthermore, small-molecule inhibitors were used to probe the global impact of its inhibition on the proteome. Areas covered: We review here recent HSP90-related interactomics and total proteome studies and their relevance for research on cancer, neurodegenerative and pathogen diseases. Expert commentary: Proteomics experiments are our best chance to identify the context-dependent global proteome of HSP90 and thus uncover and understand its disease-specific biology. However, understanding the complexity of HSP90 will require multiple complementary, quantitative approaches and novel bioinformatics to translate interactions into ordered functional networks and pathways. Developing therapies will necessitate more knowledge on HSP90 complexes and networks with disease relevance and on total proteome changes induced by their perturbation. Most work has been done in cancer, thus a lot remains to be done in the context of other diseases.
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http://dx.doi.org/10.1080/14789450.2017.1389649DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6027630PMC
December 2017

Genetic variants of mucins: unexplored conundrum.

Carcinogenesis 2017 07;38(7):671-679

Department of Biochemistry and Molecular Biology.

Alternative gene splicing, occurring ubiquitously in multicellular organisms can produce several protein isoforms with putatively different functions. The enormously extended genomic structure of mucin genes characterized by the presence of multiple exons encoding various domains may result in functionally diverse repertoire of mucin proteins due to alternative splicing. Splice variants (Svs) and mutations in mucin genes have been observed in various cancers and shown to participate in cancer progression and metastasis. Although several mucin Svs have been identified, their potential functions remain largely unexplored with the exception of the Svs of MUC1 and MUC4. A few studies have examined the expression of MUC1 and MUC4 Svs in cancer and indicated their potential involvement in promoting cancer cell proliferation, invasion, migration, angiogenesis and inflammation. Herein we review the current understanding of mucin Svs in cancer and inflammation and discuss the potential impact of splicing in generating a functionally diverse repertoire of mucin gene products. We also performed mutational analysis of mucin genes across five major cancer types in International Cancer Genome Consortium database and found unequal mutational rates across the panel of cancer-associated mucins. Although the functional role of mucins in the pathobiology of various malignancies and their utility as diagnostic and therapeutic targets remain undisputed, these attributes need to be reevaluated in light of the potentially unique functions of disease-specific genetic variants of mucins. Thus, the expressional and functional characterization of the genetic variants of mucins may provide avenues to fully exploit their potential as novel biomarkers and therapeutic targets.
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http://dx.doi.org/10.1093/carcin/bgw120DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5862316PMC
July 2017

Bile acids-mediated overexpression of MUC4 via FAK-dependent c-Jun activation in pancreatic cancer.

Mol Oncol 2016 08 29;10(7):1063-77. Epub 2016 Apr 29.

Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, United States; Buffett Cancer Center, Omaha, NE 68198, United States; Eppley Institute for Research in Cancer and Allied Diseases, Omaha, NE 68198, United States; Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, United States. Electronic address:

The majority of pancreatic cancer (PC) patients are clinically presented with obstructive jaundice with elevated levels of circulatory bilirubin and alkaline phosphatases. In the current study, we examined the implications of bile acids (BA), an important component of bile, on the pathophysiology of PC and investigated their mechanistic association in tumor-promoting functions. Integration of results from PC patient samples and autochthonous mouse models showed an elevated levels of BA (p < 0.05) in serum samples compared to healthy controls. Similarly, an elevated BA levels was observed in pancreatic juice derived from PC patients (p < 0.05) than non-pancreatic non-healthy (NPNH) controls, further establishing the clinical association of BA with the pathogenesis of PC. The tumor-promoting functions of BA were established by observed transcriptional upregulation of oncogenic MUC4 expression. Luciferase reporter assay revealed distal MUC4 promoter as the primary responsive site to BA. In silico analysis recognized two c-Jun binding sites at MUC4 distal promoter, which was biochemically established using ChIP assay. Interestingly, BA treatment led to an increased transcription and activation of c-Jun in a FAK-dependent manner. Additionally, BA receptor, namely FXR, which is also upregulated at transcriptional level in PC patient samples, was demonstrated as an upstream molecule in BA-mediated FAK activation, plausibly by regulating Src activation. Altogether, these results demonstrate that elevated levels of BA increase the tumorigenic potential of PC cells by inducing FXR/FAK/c-Jun axis to upregulate MUC4 expression, which is overexpressed in pancreatic tumors and is known to be associated with progression and metastasis of PC.
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http://dx.doi.org/10.1016/j.molonc.2016.04.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4972654PMC
August 2016

Novel HER3/MUC4 oncogenic signaling aggravates the tumorigenic phenotypes of pancreatic cancer cells.

Oncotarget 2015 Aug;6(25):21085-99

Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA.

Several studies have demonstrated that MUC4 is involved in progression and metastasis of pancreatic cancer (PC). Here, we report that HER3/MUC4 interaction in HER2 low cells is critical in driving pancreatic tumorigenesis. Upon HER2 knockdown, we observed elevated expression of HER3 and MUC4 and their interactions, which was confirmed by immunoprecipitation and bioinformatics analyses. In paired human PC tissues, higher percentage of HER3 positivity (10/33, 30.3%; p = 0.001) was observed than HER2 (5/33, 15.1%; p = 0.031), which was further confirmed in spontaneous mice (KPC; KrasG12D; Trp53R172H/+; Pdx-Cre) tumors of different weeks. Mechanistically, increased phosphorylation of ERK and expression of PI3K and c-Myc were observed in HER2 knockdown cells, suggesting a positive role for HER3/MUC4 in HER2 low cells. Further, HER2 knockdown resulted in increased proliferation, motility and tumorigenicity of PC cells. Consistently, transient knockdown of HER3 by siRNA in HER2 knockdown cells led to decreased proliferation. These observations led us to conclude that HER3 interacts with MUC4 to promote proliferation in HER2 low PC cells. Further, deficiency of both HER2 and HER3 leads to decreased proliferation of PC cells. Hence targeting these newly identified HER3/MUC4 signals would improve the PC patients survival by intercepting MUC4 mediated oncogenic signaling.
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http://dx.doi.org/10.18632/oncotarget.3912DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4673252PMC
August 2015

Genetically engineered mucin mouse models for inflammation and cancer.

Cancer Metastasis Rev 2015 Dec;34(4):593-609

Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, 68198-5870, USA.

Mucins are heavily O-glycosylated proteins primarily produced by glandular and ductal epithelial cells, either in membrane-tethered or secretory forms, for providing lubrication and protection from various exogenous and endogenous insults. However, recent studies have linked their aberrant overexpression with infection, inflammation, and cancer that underscores their importance in tissue homeostasis. In this review, we present current status of the existing mouse models that have been developed to gain insights into the functional role(s) of mucins under physiological and pathological conditions. Knockout mouse models for membrane-associated (Muc1 and Muc16) and secretory mucins (Muc2) have helped us to elucidate the role of mucins in providing effective and protective barrier functions against pathological threats, participation in disease progression, and improved our understanding of mucin interaction with biotic and abiotic environmental components. Emphasis is also given to available transgenic mouse models (MUC1 and MUC7), which has been exploited to understand the context-dependent regulation and therapeutic potential of human mucins during inflammation and cancer.
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http://dx.doi.org/10.1007/s10555-015-9549-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4520780PMC
December 2015

Altered Mucins (MUC) trafficking in benign and malignant conditions.

Oncotarget 2014 Sep;5(17):7272-84

Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, 68198, U.S.A. Fred and Pamela Buffett Cancer Center, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, U.S.A.

Mucins are high molecular weight O-glycoproteins that are predominantly expressed at the apical surface of epithelial cells and have wide range of functions. The functional diversity is attributed to their structure that comprises of a peptide chain with unique domains and multiple carbohydrate moieties added during posttranslational modifications. Tumor cells aberrantly overexpress mucins, and thereby promote proliferation, differentiation, motility, invasion and metastasis. Along with their aberrant expression, accumulating evidence suggest the critical role of altered subcellular localization of mucins under pathological conditions due to altered endocytic processes. The mislocalization of mucins and their interactions result in change in the density and activity of important cell membrane proteins (like, receptor tyrosine kinases) to facilitate various signaling, which help cancer cells to proliferate, survive and progress to more aggressive phenotype. In this review article, we summarize studies on mucins trafficking and provide a perspective on its importance to pathological conditions and to answer critical questions including its use for therapeutic interventions.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4202122PMC
http://dx.doi.org/10.18632/oncotarget.2370DOI Listing
September 2014

Graviola: a novel promising natural-derived drug that inhibits tumorigenicity and metastasis of pancreatic cancer cells in vitro and in vivo through altering cell metabolism.

Cancer Lett 2012 Oct 1;323(1):29-40. Epub 2012 Apr 1.

Department of Biochemistry and Molecular Biology, Omaha, NE 68198-5870, USA; Eppley Institute for Research in Cancer and Allied Diseases, Omaha, NE 68198-5870, USA; Department of Pathology and Microbiology, Omaha, NE 68198-5870, USA. Electronic address:

Pancreatic tumors are resistant to conventional chemotherapies. The present study was aimed at evaluating the potential of a novel plant-derived product as a therapeutic agent for pancreatic cancer (PC). The effects of an extract from the tropical tree Annona Muricata, commonly known as Graviola, was evaluated for cytotoxicity, cell metabolism, cancer-associated protein/gene expression, tumorigenicity, and metastatic properties of PC cells. Our experiments revealed that Graviola induced necrosis of PC cells by inhibiting cellular metabolism. The expression of molecules related to hypoxia and glycolysis in PC cells (i.e. HIF-1α, NF-κB, GLUT1, GLUT4, HKII, and LDHA) were downregulated in the presence of the extract. In vitro functional assays further confirmed the inhibition of tumorigenic properties of PC cells. Overall, the compounds that are naturally present in a Graviola extract inhibited multiple signaling pathways that regulate metabolism, cell cycle, survival, and metastatic properties in PC cells. Collectively, alterations in these parameters led to a decrease in tumorigenicity and metastasis of orthotopically implanted pancreatic tumors, indicating promising characteristics of the natural product against this lethal disease.
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http://dx.doi.org/10.1016/j.canlet.2012.03.031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3371140PMC
October 2012

Polyethylene glycol diminishes pathological effects of Citrobacter rodentium infection by blocking bacterial attachment to the colonic epithelia.

Gut Microbes 2011 Sep 1;2(5):267-73. Epub 2011 Sep 1.

Department of Medicine, Division of Gastroenterology, NorthShore University Research Institute, Evanston, IL USA.

Infections from enteric bacteria such as enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic Escherichia coli (EHEC) are a public health threat worldwide. EPEC and EHEC are extracellular pathogens, and their interaction with host surface receptors is critical to the infection process. We previously demonstrated that polyethylene glycol (PEG) downregulates surface receptors in intestinal cells. Here we show that PEG decreases β1-integrin, the surface receptor in intestinal cells that is critical for EPEC and EHEC attachment. We hypothesized that PEG would inhibit the attachment of these enteric pathogens to host cells and improve clinical signs of infection. We found that attachment of the mouse enteric pathogen Citrobacter rodentium, which belongs to the same group of pathogens as EPEC and EHEC, was attenuated by the concurrent presence of PEG. Pretreatment with PEG, without concurrent presence during infection, also reduced bacterial attachment. This finding was further supported in vivo such as that PEG administered by gavage daily during infection as well as prior to infection significantly decreased C. rodentium in the colon and improved the appearance of the infected colon in mice. In addition, PEG decreased the β1-integrin in colonic mucosa and reduced the C. rodentium-induced activation of epidermal growth factor receptors. PEG also significantly reduced infection-induced colonic inflammation. Finally, PEG efficiently reduced C. rodentium shedding from the colon during infection. In conclusion, PEG can be an efficient and safe preventive agent against EPEC and EHEC infections.
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http://dx.doi.org/10.4161/gmic.2.5.18256DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3242793PMC
September 2011

WITHDRAWN: Recent Advances in Angiopoietin Biology in Cancer - A Review.

Clin Oncol (R Coll Radiol) 2011 Mar 10. Epub 2011 Mar 10.

Department of Biochemistry, All India Institute of Medical Sciences, New Delhi 110029, India.

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.
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http://dx.doi.org/10.1016/j.clon.2011.01.153DOI Listing
March 2011

Angiopoietin-2: a potential novel diagnostic marker in multiple myeloma.

Clin Biochem 2011 Jun 12;44(8-9):590-5. Epub 2011 Feb 12.

Department of Biochemistry, All India Institute of Medical Sciences, Ansari Nagar, New Delhi-110029, India.

Background: Multiple myeloma (MM) was the first hematological malignancy in which a prognostic relevance of bone marrow (BM) angiogenesis was reported. Microenvironment formed by reactive oxygen species, growth factors and chemokines initiates the process of BM angiogenesis. Among the angiopoietins, angiopoietin-1 is involved in vessel stability, whereas angiopoietin-2 is involved in vessel sprouting.

Design And Methods: Circulatory levels of angiopoietin-1, angiopoietin-2 and VEGF in 62 MM patients and 50 healthy controls were determined using ELISA.

Results: Significant increase in VEGF and angiopoietin-2 level was observed in patients which correlated positively with the severity of the disease, whereas no alteration was observed in angiopoietin-1 levels.

Conclusion: Significant elevation in angiopoietin-2 and VEGF levels and their correlation with severity of the disease indicate their utility as potential tumor markers along with β(2)- microglobulin and might also suggest new therapeutic target for anticancer treatment.
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http://dx.doi.org/10.1016/j.clinbiochem.2011.01.010DOI Listing
June 2011

Involvement of p21cip1/waf1 in the anti-proliferative effects of polyethylene glycol in colon carcinogenesis.

Int J Oncol 2011 Feb 17;38(2):529-36. Epub 2010 Dec 17.

Department of Medicine, Northshore University Healthcare System, Evanston, IL 60201, USA.

Polyethylene glycol (PEG) is a safe and effective chemopreventive agent against colorectal carcinogenesis in cell culture, animal models and human subjects. Although the precise molecular mechanism is unclear, we previously reported that PEG suppresses colonic epithelial proliferation. As cellular proliferation is driven by complex G1-S phase transition, we now characterize the role of PEG on cell cycle regulation. We focused our attention on the effect of PEG on the CDK inhibitor p21cip1/waf1, which is implicated in early colon carcinogenesis and is upregulated by non-steroidal anti-inflammatory drugs. These studies were done in the azoxymethane-treated (AOM) rat model as well as in HT-29 colon cancer cells. Immunohistochemical analysis revealed that while AOM decreased the p21 expression (75%, p<0.01) in the premalignant colonic mucosa, PEG induced p21 levels back to normal. These findings paralleled a decreased BrdUrd incorporation (78%, p<0.001) and hypophosphorylated retinoblastoma protein (Rb; by 47%) signifying PEG's antiproliferative activity. Furthermore, in HT-29 cells, PEG decreased proliferation as measured by PCNA (68% reduction), increased p21 expression (2.3-fold), induced cell cycle arrest during G0/G1 phase (45% reduction in S phase cells) and inhibited the phosphorylation of Rb (by 52% compared to untreated). PEG caused greater than a 2-fold induction of protein and mRNA level of p21cip1/waf1 in HT-29 cells. These results demonstrate for the first time that PEG is involved in p21 regulation concomitant with G1S phase cell cycle arrest and it is through these effects that it can exert its anti-proliferative and hence chemopreventive role.
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http://dx.doi.org/10.3892/ijo.2010.875DOI Listing
February 2011

Tumor suppressor FOXO3 mediates signals from the EGF receptor to regulate proliferation of colonic cells.

Am J Physiol Gastrointest Liver Physiol 2011 Feb 25;300(2):G264-72. Epub 2010 Nov 25.

NorthShore Univ. Research Institute, Dept. of Medicine, Div. of Gastroenterology, 1001 University Pl.; Rm. 314, Evanston, IL 60201, USA.

Epithelial proliferation, critical for homeostasis, healing, and colon cancer progression, is in part controlled by epidermal growth factor receptor (EGFR). Proliferation of colonic epithelia can be induced by Citrobacter rodentium infection, and we have demonstrated that activity of tumor suppressor FOXO3 was attenuated after this infection. Thus the aim of this study was to determine the contribution of FOXO3 in EGFR-dependent proliferation of intestinal epithelia and colon cancer cell lines. In this study we show that, during infection with C. rodentium, EGFR was significantly phosphorylated in colonic mucosa and Foxo3 deficiency in this model lead to an increased number of bromodeoxyuridine-positive cells. In vitro, in human colon cancer cells, increased expression and activation of EGFR was associated with proliferation that leads to FOXO3 phosphorylation (inactivation). Following EGFR activation, FOXO3 was phosphorylated (via phosphatidylinositol 3-kinase/Akt) and translocated to the cytosol where it was degraded. Moreover, inhibition of proliferation by overexpressing FOXO3 was not reversed by the EGFR signaling, implicating FOXO3 as one of the regulators downstream of EGFR. FOXO3 binding to the promoter of the cell cycle inhibitor p27kip1 was decreased by EGFR signaling, suggesting its role in EGFR-dependent proliferation. In conclusion, we show that proliferation in colonic epithelia and colon cancer cells, stimulated by EGFR, is mediated via loss of FOXO3 activity and speculate that FOXO3 may serve as a target in the development of new pharmacological treatments of proliferative diseases.
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http://dx.doi.org/10.1152/ajpgi.00416.2010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3043652PMC
February 2011

Dysregulation in T helper 1/T helper 2 cytokine ratios in patients with multiple myeloma.

Leuk Lymphoma 2010 May;51(5):920-7

Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, 110029, India.

We have assessed alterations of Th1 and Th2 derived cytokines in the progression of multiple myeloma (MM) by determining their circulatory concentrations in patients with MM and healthy controls and correlated observations with grade and severity of the disease. The study group consisted of 112 subjects: 62 patients with MM and 50 healthy controls. Regarding serum levels of Th1 cytokines, IFN-gamma was significantly lower and IL-2 was non-significantly increased, while regarding levels of Th2 cytokines, IL-4 and IL-10 were significantly elevated. Results of our study indicate that a marked polarization exists toward Th2 cytokines in MM while Th1 cytokines remain suppressed.
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http://dx.doi.org/10.3109/10428191003699563DOI Listing
May 2010