Medicine and Health Sciences Commons^™

Repurposing Niclosamide For Targeting Pancreatic Cancer By Inhibiting Hh/Gli Non-Canonical Axis Of Gsk3Β, Jyoti B. Kaushal, Rakesh Bhatia, Ranjana K. Kanchan, Pratima Raut, Surya Mallapragada, Quan P. Ly, Surinder K. Batra, Satyanarayana Rachagani

Journal Articles: Biochemistry & Molecular Biology

Niclosamide (Nic), an FDA-approved anthelmintic drug, is reported to have anti-cancer efficacy and is being assessed in clinical trials for various solid tumors. Based on its ability to target multiple signaling pathways, in the present study, we evaluated the therapeutic efficacy of Nic on pancreatic cancer (PC) in vitro. We observed an anti-cancerous effect of this drug as shown by the G0/G1 phase cell cycle arrest, inhibition of PC cell viability, colony formation, and migration. Our results revealed the involvement of mitochondrial stress and mTORC1-dependent autophagy as the predominant players of Nic-induced PC cell death. Significant reduction of Nic-induced reactive …

Exogenous Flupirtine As Potential Treatment For Cln3 Disease, Katia Maalouf, Joelle Makoukji, Sara Saab, Nadine J. Makhoul, Angelica V. Carmona, Nihar Kinarivala, Noël Ghanem, Paul C. Trippier, Rose-Mary Boustany

Journal Articles: Pharmaceutical Sciences

CLN3 disease is a fatal neurodegenerative disorder affecting children. Hallmarks include brain atrophy, accelerated neuronal apoptosis, and ceramide elevation. Treatment regimens are supportive, highlighting the importance of novel, disease-modifying drugs. Flupirtine and its new allyl carbamate derivative (compound 6) confer neuroprotective effects in CLN3-deficient cells. This study lays the groundwork for investigating beneficial effects in Cln3^Δex7/8 mice. WT/Cln3^Δex7/8 mice received flupirtine/compound 6/vehicle for 14 weeks. Short-term effect of flupirtine or compound 6 was tested using a battery of behavioral testing. For flupirtine, gene expression profiles, astrogliosis, and neuronal cell counts were determined. Flupirtine improved neurobehavioral parameters in …

Vitamin E Δ-Tocotrienol Sensitizes Human Pancreatic Cancer Cells To Trail-Induced Apoptosis Through Proteasome-Mediated Down-Regulation Of C-Flip, Rony A. Francois, Anying Zhang, Kazim Husain, Chen Wang, Sean Hutchinson, Michael Kongnyuy, Surinder K. Batra, Domenico Coppola, Said M. Sebti, Mokenge P. Malafa

Journal Articles: Biochemistry & Molecular Biology

Background: Vitamin E δ-tocotrienol (VEDT), a vitamin E compound isolated from sources such as palm fruit and annatto beans, has been reported to have cancer chemopreventive and therapeutic effects.

Methods: We report a novel function of VEDT in augmenting tumor necrosis factor-related apoptosis-inducing ligand- (TRAIL-) induced apoptosis in pancreatic cancer cells. The effects of VEDT were shown by its ability to trigger caspase-8-dependent apoptosis in pancreatic cancer cells.

Results: When combined with TRAIL, VEDT significantly augmented TRAIL-induced apoptosis of pancreatic cancer cells. VEDT decreased cellular FLICE inhibitory protein (c-FLIP) levels without consistently modulating the expression of decoy death receptors 1, …

Anti-Human Interleukin(Il)-4 Clone 8d4-8 Cross-Reacts With Myosin-9 Associated With Apoptotic Cells And Should Not Be Used For Flow Cytometry Applications Querying Il-4 Expression, Robert Z. Harms, Kiana Borengasser, Vikas Kumar, Nora Sarvetnick

Journal Articles: Surgery

Interleukin(IL)-4 is produced by T cells and other leukocytes and is a critical mediator of monocyte and B cell responses. During routine flow cytometry panel validation for the investigation of intracellular cytokines, we observed unique IL-4 expression patterns associated with the widely available monoclonal antibody 8D4-8. Namely, IL-4 (8D4-8) expression was observed in the absence of cellular activation and enhanced following staurosporine exposure. Mass spectrometry analysis of immunoprecipitates from peripheral blood lymphocytes (PBL) revealed that 8D4-8 cross-reacts with the ubiquitous cytoskeletal protein myosin-9. We confirmed these results by western blotting immunoprecipitates, using immunofluorescence among staurosporine-treated Caco-2 cells, and by surface-labeling …

Inhibition Of Geranylgeranyl Diphosphate Synthase Is A Novel Therapeutic Strategy For Pancreatic Ductal Adenocarcinoma, Staci L. Haney, Michelle L. Varney, Yashpal S. Chhonker, Simon Shin, Kamiya Mehla, Ayrianne J. Crawford, Heather Jensen Smith, Lynette M. Smith, Daryl J. Murry, Michael A. Hollingsworth, Sarah A. Holstein

Journal Articles: Eppley Institute

Rab proteins play an essential role in regulating intracellular membrane trafficking processes. Rab activity is dependent upon geranylgeranylation, a post-translational modification that involves the addition of 20-carbon isoprenoid chains via the enzyme geranylgeranyl transferase (GGTase) II. We have focused on the development of inhibitors against geranylgeranyl diphosphate synthase (GGDPS), which generates the isoprenoid donor (GGPP), as anti-Rab agents. Pancreatic ductal adenocarcinoma (PDAC) is characterized by abnormal mucin production and these mucins play important roles in tumor development, metastasis and chemo-resistance. We hypothesized that GGDPS inhibitor (GGDPSi) treatment would induce PDAC cell death by disrupting mucin trafficking, thereby inducing the unfolded …

Tgfβ/Smad3 Regulates Proliferation And Apoptosis Through Irs-1 Inhibition In Colon Cancer Cells., Katie L. Bailey, Ekta Agarwal, Sanjib Chowdhury, Jiangtao Luo, Michael G. Brattain, Jennifer D. Black, J. Wang

Journal Articles: Eppley Institute

In this study, we have uncovered a novel crosstalk between TGFβ and IGF-1R signaling pathways. We show for the first time that expression and activation of IRS-1, an IGF-1R adaptor protein, is decreased by TGFβ/Smad3 signaling. Loss or attenuation of TGFβ activation leads to elevated expression and phosphorylation of IRS-1 in colon cancer cells, resulting in enhanced cell proliferation, decreased apoptosis and increased tumor growth in vitro and in vivo. Downregulation of IRS-1 expression reversed Smad3 knockdown-mediated oncogenic phenotypes, indicating that TGFβ/Smad3 signaling inhibits cell proliferation and increases apoptosis at least partially through the inhibition of IRS-1 expression and activation. …

Molecular Manipulation Of Keratin 8/18 Intermediate Filaments: Modulators Of Fas-Mediated Death Signaling In Human Ovarian Granulosa Tumor Cells., Sarah K. Trisdale, Nicolette M. Schwab, Xiaoying Hou, John S. Davis, David H. Townson

Journal Articles: Obstetrics & Gynecology

BACKGROUND: Granulosa cell tumors (GCT) are a rare ovarian neoplasm but prognosis is poor following recurrence. Keratin intermediate filaments expressed in these tumors are a diagnostic marker, yet paradoxically, may also constitute a target for therapeutic intervention. In the current study, we evaluated keratin 8/18 (K8/18) filament expression as a mechanism of resistance to apoptosis in GCT, specifically focusing on regulation of the cell surface death receptor, Fas (FAS).

METHODS: The GCT cell line, KGN, was transiently transfected with siRNA to KRT8 and KRT18 to reduce K8/18 filament expression. Expression of K8/18, FAS, and apoptotic proteins (PARP, cleaved PARP) were …

Saturated Free Fatty Acids Induce Cholangiocyte Lipoapoptosis, Sathish Kumar Natarajan, Sally A. Ingham, Ashley M. Mohr, Cody J. Wehrkamp, Anuttoma Ray, Sohini Roy, Sophie C. Cazanave, Mary A. Smith, Justin L. Mott

Journal Articles: Biochemistry & Molecular Biology

Recent studies have identified a cholestatic variant of nonalcoholic fatty liver disease (NAFLD) with portal inflammation and ductular reaction. Based on reports of biliary damage, as well as increased circulating free fatty acids (FFAs) in NAFLD, we hypothesized the involvement of cholangiocyte lipoapoptosis as a mechanism of cellular injury. Here, we demonstrate that the saturated FFAs palmitate and stearate induced robust and rapid cell death in cholangiocytes. Palmitate and stearate induced cholangiocyte lipoapoptosis in a concentration-dependent manner in multiple cholangiocyte-derived cell lines. The mechanism of lipoapoptosis relied on the activation of caspase 3/7 activity. There was also a significant up-regulation …

Inhibition Of Rac1 Gtpase Sensitizes Pancreatic Cancer Cells To Γ-Irradiation., Y Yan, Ashley L. Hein, Asserewou Etekpo, Katrina M. Burchett, Chi Lin, Charles A. Enke, Surinder K. Batra, Kenneth Cowan, M Ouellette

Journal Articles: Radiation Oncology

Radiation therapy is a staple treatment for pancreatic cancer. However, owing to the intrinsic radioresistance of pancreatic cancer cells, radiation therapy often fails to increase survival of pancreatic cancer patients. Radiation impedes cancer cells by inducing DNA damage, which can activate cell cycle checkpoints. Normal cells possess both a G1 and G2 checkpoint. However, cancer cells are often defective in G1 checkpoint due to mutations/alterations in key regulators of this checkpoint. Accordingly, our results show that normal pancreatic ductal cells respond to ionizing radiation (IR) with activation of both checkpoints whereas pancreatic cancer cells respond to IR with G2/M arrest …

Functional Proteomic Analysis Reveals The Involvement Of Kiaa1199 In Breast Cancer Growth, Motility And Invasiveness., Mohammad-Saeid Jami, Jinxuan Hou, Miao Liu, M L. Varney, Hesham Hassan, Jixin Dong, Liying Geng, J. Wang, Fang Yu, Xin Huang, Hong Peng, Kai Fu, Yan Li, Rakesh Singh, Shi-Jian Ding

Journal Articles: Pathology and Microbiology

BACKGROUND: KIAA1199 is a recently identified novel gene that is up-regulated in human cancer with poor survival. Our proteomic study on signaling polarity in chemotactic cells revealed KIAA1199 as a novel protein target that may be involved in cellular chemotaxis and motility. In the present study, we examined the functional significance of KIAA1199 expression in breast cancer growth, motility and invasiveness.

METHODS: We validated the previous microarray observation by tissue microarray immunohistochemistry using a TMA slide containing 12 breast tumor tissue cores and 12 corresponding normal tissues. We performed the shRNA-mediated knockdown of KIAA1199 in MDA-MB-231 and HS578T cells to …

Inhibition Of Rac1 Gtpase Sensitizes Pancreatic Cancer Cells To Γ-Irradiation, Y Yan, Ashley L. Hein, Asserewou Etekpo, Katrina M. Burchett, Chi Lin, Charles A. Enke, Surinder K. Batra, Kenneth Cowan, Michel M. Ouellette

Journal Articles: Biochemistry & Molecular Biology

Radiation therapy is a staple treatment for pancreatic cancer. However, owing to the intrinsic radioresistance of pancreatic cancer cells, radiation therapy often fails to increase survival of pancreatic cancer patients. Radiation impedes cancer cells by inducing DNA damage, which can activate cell cycle checkpoints. Normal cells possess both a G1 and G2 checkpoint. However, cancer cells are often defective in G1 checkpoint due to mutations/alterations in key regulators of this checkpoint. Accordingly, our results show that normal pancreatic ductal cells respond to ionizing radiation (IR) with activation of both checkpoints whereas pancreatic cancer cells respond to IR with G2/M arrest …

The G-Protein-Coupled Estrogen Receptor Agonist G-1 Suppresses Proliferation Of Ovarian Cancer Cells By Blocking Tubulin Polymerization., Cheng Wang, Xiangmin Lv, Chunbo He, G Hua, M-Y Tsai, John S. Davis

Journal Articles: Obstetrics & Gynecology

The G-protein-coupled estrogen receptor 1 (GPER) has recently been reported to mediate the non-genomic action of estrogen in different types of cells and tissues. G-1 (1-[4-(6-bromobenzo[1,3] dioxol-5yl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinolin-8-yl]-ethanone) was developed as a potent and selective agonist for GPER. G-1 has been shown to induce the expression of genes and activate pathways that facilitate cancer cell proliferation by activating GPER. Here we demonstrate that G-1 has an anticancer potential with a mechanism similar to vinca alkaloids, the commonly used chemotherapy drugs. We found that G-1 blocks tubulin polymerization and thereby interrupts microtubule assembly in ovarian cancer cells leading to the arrest of …

Discovery Of Molecular Associations Among Aging, Stem Cells, And Cancer Based On Gene Expression Profiling., Xiaosheng Wang

Journal Articles: Genetics, Cell Biology & Anatomy

The emergence of a huge volume of "omics" data enables a computational approach to the investigation of the biology of cancer. The cancer informatics approach is a useful supplement to the traditional experimental approach. I reviewed several reports that used a bioinformatics approach to analyze the associations among aging, stem cells, and cancer by microarray gene expression profiling. The high expression of aging- or human embryonic stem cell-related molecules in cancer suggests that certain important mechanisms are commonly underlying aging, stem cells, and cancer. These mechanisms are involved in cell cycle regulation, metabolic process, DNA damage response, apoptosis, p53 signaling …

Marked Improvement Of Cytotoxic Effects Induced By Docetaxel On Highly Metastatic And Androgen-Independent Prostate Cancer Cells By Downregulating Macrophage Inhibitory Cytokine-1., M Mimeault, Sonny L. Johansson, Surinder K. Batra

Journal Articles: Biochemistry & Molecular Biology

BACKGROUND: Overexpression of macrophage inhibitory cytokine-1 (MIC-1) frequently occurs during the progression of prostate cancer (PC) to androgen-independent (AI) and metastatic disease states and is associated with a poor outcome of patients.

METHODS: The gain- and loss-of-function analyses of MIC-1 were performed to establish its implications for aggressive and chemoresistant phenotypes of metastatic and AI PC cells and the benefit of its downregulation for reversing docetaxel resistance.

RESULTS: The results have indicated that an enhanced level of secreted MIC-1 protein in PC3 cells is associated with their acquisition of epithelial-mesenchymal transition features and higher invasive capacity and docetaxel resistance. Importantly, …

Hypoxia-Inducing Factors As Master Regulators Of Stemness Properties And Altered Metabolism Of Cancer- And Metastasis-Initiating Cells., Murielle Mimeault, Surinder K. Batra

Journal Articles: Biochemistry & Molecular Biology

Accumulating lines of experimental evidence have revealed that hypoxia-inducible factors, HIF-1α and HIF-2α, are key regulators of the adaptation of cancer- and metastasis-initiating cells and their differentiated progenies to oxygen and nutrient deprivation during cancer progression under normoxic and hypoxic conditions. Particularly, the sustained stimulation of epidermal growth factor receptor (EGFR), insulin-like growth factor-1 receptor (IGF-1R), stem cell factor (SCF) receptor KIT, transforming growth factor-β receptors (TGF-βRs) and Notch and their downstream signalling elements such as phosphatidylinositol 3'-kinase (PI3K)/Akt/molecular target of rapamycin (mTOR) may lead to an enhanced activity of HIFs. Moreover, the up-regulation of HIFs in cancer cells may …

Visualizing Spatiotemporal Dynamics Of Apoptosis After G1 Arrest By Human T Cell Leukemia Virus Type 1 Tax And Insights Into Gene Expression Changes Using Microarray-Based Gene Expression Analysis., Mariluz Araínga, Hironobu Murakami, Yoko Aida

Journal Articles: Pharmacology & Experimental Neuroscience

BACKGROUND: Human T cell leukemia virus type 1 (HTLV-1) Tax is a potent activator of viral and cellular gene expression that interacts with a number of cellular proteins. Many reports show that Tax is capable of regulating cell cycle progression and apoptosis both positively and negatively. However, it still remains to understand why the Tax oncoprotein induces cell cycle arrest and apoptosis, or whether Tax-induced apoptosis is dependent upon its ability to induce G1 arrest. The present study used time-lapse imaging to explore the spatiotemporal patterns of cell cycle dynamics in Tax-expressing HeLa cells containing the fluorescent ubiquitination-based cell cycle …

Transforming Growth Factor-Β Suppresses Metastasis In A Subset Of Human Colon Carcinoma Cells., Neka A.K. Simms, Ashwani Rajput, Elizabeth A. Sharratt, Melanie Ongchin, Carol A. Teggart, J. Wang, Michael G. Brattain

Journal Articles: Eppley Institute

BACKGROUND: TGFβ signaling has typically been associated with suppression of tumor initiation while the role it plays in metastasis is generally associated with progression of malignancy. However, we present evidence here for an anti-metastatic role of TGFβ signaling.

METHODS: To test the importance of TGFβ signaling to cell survival and metastasis we compared human colon carcinoma cell lines that are either non-tumorigenic with TGFβ response (FET), or tumorigenic with TGFβ response (FETα) or tumorigenic with abrogated TGFβ response via introduction of dominant negative TGFβRII (FETα/DN) and their ability to metastasize. Metastatic competency was assessed by orthotopic transplantation. Metastatic colony formation …

Perk-Dependent Repression Of Mir-106b-25 Cluster Is Required For Er Stress-Induced Apoptosis., S. Gupta, D. E. Read, A. Deepti, K. Cawley, A. Gupta, D. Oommen, T. Verfaillie, S. Matus, Mary A. Smith, Justin L. Mott, P. Agostinis, C. Hetz, A. Samali

Journal Articles: Biochemistry & Molecular Biology

Activation of the unfolded protein response sensor PKR-like endoplasmic reticulum kinase (Perk) attenuates endoplasmic reticulum (ER) stress levels. Conversantly, if the damage is too severe and ER function cannot be restored, this signaling branch triggers apoptosis. Bcl-2 homology 3-only family member Bim is essential for ER stress-induced apoptosis. However, the regulatory mechanisms controlling Bim activation under ER stress conditions are not well understood. Here, we show that downregulation of the miR-106b-25 cluster contributes to ER stress-induced apoptosis and the upregulation of Bim. Hypericin-mediated photo-oxidative ER damage induced Perk-dependent cell death and led to a significant decrease in the levels of …

Identification Of Bovine Leukemia Virus Tax Function Associated With Host Cell Transcription, Signaling, Stress Response And Immune Response Pathway By Microarray-Based Gene Expression Analysis., Mariluz Araínga, Eri Takeda, Yoko Aida

Journal Articles: Pharmacology & Experimental Neuroscience

BACKGROUND: Bovine leukemia virus (BLV) is associated with enzootic bovine leukosis and is closely related to human T-cell leukemia virus type I. The Tax protein of BLV is a transcriptional activator of viral replication and a key contributor to oncogenic potential. We previously identified interesting mutant forms of Tax with elevated (TaxD247G) or reduced (TaxS240P) transactivation effects on BLV replication and propagation. However, the effects of these mutations on functions other than transcriptional activation are unknown. In this study, to identify genes that play a role in the cascade of signal events regulated by wild-type and mutant Tax proteins, we …

Mir-25 Targets Tnf-Related Apoptosis Inducing Ligand (Trail) Death Receptor-4 And Promotes Apoptosis Resistance In Cholangiocarcinoma., Nataliya Razumilava, Steve F. Bronk, Rory L. Smoot, Christian D. Fingas, Nathan W. Werneburg, Lewis R. Roberts, Justin L. Mott

Journal Articles: Biochemistry & Molecular Biology

It has been established that microRNA expression and function contribute to phenotypic features of malignant cells, including resistance to apoptosis. Although targets and functional roles for a number of microRNAs have been described in cholangiocarcinoma, many additional microRNAs dysregulated in this tumor have not been assigned functional roles. In this study, we identify elevated miR-25 expression in malignant cholangiocarcinoma cell lines as well as patient samples. In cultured cells, treatment with the Smoothened inhibitor, cyclopamine, reduced miR-25 expression, suggesting Hedgehog signaling stimulates miR-25 production. Functionally, miR-25 was shown to protect cells against TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis. Correspondingly, antagonism of …

Death Receptor 5 Signaling Promotes Hepatocyte Lipoapoptosis., Sophie C. Cazanave, Justin L. Mott, Steven F. Bronk, Nathan W. Werneburg, Christian D. Fingas, X Wei Meng, Niklas Finnberg, Wafik S. El-Deiry, Scott H. Kaufmann, Gregory J. Gores

Journal Articles: Biochemistry & Molecular Biology

Nonalcoholic steatohepatitis is characterized by hepatic steatosis, elevated levels of circulating free fatty acids (FFA), endoplasmic reticulum (ER) stress, and hepatocyte lipoapoptosis. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) death receptor 5 (DR5) is significantly elevated in patients with nonalcoholic steatohepatitis, and steatotic hepatocytes demonstrate increased sensitivity to TRAIL-mediated cell death. Nonetheless, a role for TRAIL and/or DR5 in mediating lipoapoptotic pathways is unexplored. Here, we examined the contribution of DR5 death signaling to lipoapoptosis by free fatty acids. The toxic saturated free fatty acid palmitate induces an increase in DR5 mRNA and protein expression in Huh-7 human hepatoma cells leading …

Upregulation Of Cathepsin D In The Caudate Nucleus Of Primates With Experimental Parkinsonism., Sowmya V. Yelamanchili, Amrita Datta Chaudhuri, Claudia T. Flynn, Howard S. Fox

Journal Articles: Pharmacology & Experimental Neuroscience

BACKGROUND: In Parkinson's disease there is progressive loss of dopamine containing neurons in the substantia nigra pars compacta. The neuronal damage is not limited to the substantia nigra but progresses to other regions of brain, leading to loss of motor control as well as cognitive abnormalities. The purpose of this study was to examine causes of progressive damage in the caudate nucleus, which plays a major role in motor coordination and cognition, in experimental Parkinson's disease.

RESULTS: Using chronic 1-methyl-4phenyl-1,2,3,6-tetrahydropyridine treatment of rhesus monkeys to model Parkinson's disease, we found a upregulation of Cathepsin D, a lysosomal aspartic protease, in …

Inhibition Of Phosphorylated C-Met In Rhabdomyosarcoma Cell Lines By A Small Molecule Inhibitor Su11274., Jinxuan Hou, Jixin Dong, Lijun Sun, Liying Geng, J. Wang, Jialin C. Zheng, Yan Li, Julia A. Bridge, Steven H. Hinrichs, Shi-Jian Ding

Journal Articles: Pathology and Microbiology

BACKGROUND: c-Met is a receptor tyrosine kinase (RTK) that is over-expressed in a variety of cancers and involved in cell growth, invasion, metastasis and angiogenesis. In this study, we investigated the role of c-Met in rhabdomyosarcoma (RMS) using its small molecule inhibitor SU11274, which has been hypothesized to be a potential therapeutic target for RMS.

METHODS: The expression level of phosphorylated c-Met in RMS cell lines (RD, CW9019 and RH30) and tumor tissues was assessed by phospho-RTK array and immunohistochemistry, respectively. The inhibition effects of SU11274 on RMS cells were studied with regard to intracellular signaling, cell proliferation, cell cycle …

Renal Thrombotic Microangiopathy In Mice With Combined Deletion Of Endocytic Recycling Regulators Ehd3 And Ehd4., Manju George, Mark A. Rainey, Mayumi Naramura, Kirk W. Foster, Melissa S. Holzapfel, Laura L. Willoughby, Guoguang Ying, Rasna M. Goswami, Channabasavaiah B. Gurumurthy, Vimla Band, Simon C. Satchell, Hamid Band

Journal Articles: Eppley Institute

Eps15 Homology Domain-containing 3 (EHD3), a member of the EHD protein family that regulates endocytic recycling, is the first protein reported to be specifically expressed in the glomerular endothelium in the kidney; therefore we generated Ehd3(-/-) mice and assessed renal development and pathology. Ehd3(-/-) animals showed no overt defects, and exhibited no proteinuria or glomerular pathology. However, as the expression of EHD4, a related family member, was elevated in the glomerular endothelium of Ehd3(-/-) mice and suggested functional compensation, we generated and analyzed Ehd3(-/-); Ehd4(-/-) mice. These mice were smaller, possessed smaller and paler kidneys, were proteinuric and died between …

Hedgehog Inhibition Promotes A Switch From Type Ii To Type I Cell Death Receptor Signaling In Cancer Cells., Satoshi Kurita, Justin L. Mott, Sophie C. Cazanave, Christian D. Fingas, Maria E. Guicciardi, Steve F. Bronk, Lewis R. Roberts, Martin E. Fernandez-Zapico, Gregory J. Gores

Journal Articles: Biochemistry & Molecular Biology

TRAIL is a promising therapeutic agent for human malignancies. TRAIL often requires mitochondrial dysfunction, referred to as the Type II death receptor pathway, to promote cytotoxicity. However, numerous malignant cells are TRAIL resistant due to inhibition of this mitochondrial pathway. Using cholangiocarcinoma cells as a model of TRAIL resistance, we found that Hedgehog signaling blockade sensitized these cancer cells to TRAIL cytotoxicity independent of mitochondrial dysfunction, referred to as Type I death receptor signaling. This switch in TRAIL requirement from Type II to Type I death receptor signaling was demonstrated by the lack of functional dependence on Bid/Bim and Bax/Bak, …

Palmitoleate Attenuates Palmitate-Induced Bim And Puma Up-Regulation And Hepatocyte Lipoapoptosis., Yuko Akazawa, Sophie Cazanave, Justin L. Mott, Nafisa Elmi, Steven F. Bronk, Shigeru Kohno, Michael R. Charlton, Gregory J. Gores

Journal Articles: Biochemistry & Molecular Biology

BACKGROUND & AIMS: Saturated free fatty acids induce hepatocyte lipoapoptosis. This lipotoxicity involves an endoplasmic reticulum stress response, activation of JNK, and altered expression and function of Bcl-2 proteins. The mono-unsaturated free fatty acid palmitoleate is an adipose-derived lipokine which suppresses free fatty acid-mediated lipotoxicity by unclear mechanisms. Herein we examined the mechanisms responsible for cytoprotection.

METHODS: We employed isolated human and mouse primary hepatocytes, and the Huh-7 and Hep 3B cell lines for these studies. Cells were incubated in presence and absence of palmitate (16:0), stearate (18:0), and or palmitoleate (16:1, n-7).

RESULTS: Palmitoleate significantly reduced lipoapoptosis by palmitate …

P66shc--A Longevity Redox Protein In Human Prostate Cancer Progression And Metastasis : P66shc In Cancer Progression And Metastasis., Mythilypriya Rajendran, Paul Thomes, Li Zhang, Suresh Veeramani, Ming-Fong Lin

Journal Articles: Biochemistry & Molecular Biology

p66Shc, a 66 kDa proto-oncogene Src homologous-collagen homologue (Shc) adaptor protein, is classically known in mediating receptor tyrosine kinase signaling and recently identified as a sensor to oxidative stress-induced apoptosis and as a longevity protein in mammals. The expression of p66Shc is decreased in mice and increased in human fibroblasts upon aging and in aging-related diseases, including prostate cancer. p66Shc protein level correlates with the proliferation of several carcinoma cells and can be regulated by steroid hormones. Recent advances point that p66Shc protein plays a role in mediating cross-talk between steroid hormones and redox signals by serving as a common …

Suppression Of Erbb-2 In Androgen-Independent Human Prostate Cancer Cells Enhances Cytotoxic Effect By Gemcitabine In An Androgen-Reduced Environment., Li Zhang, Jeffrey S. Davis, Stanislav Zelivianski, Fen-Fen Lin, Rachel Schutte, Thomas L. Davis, Ralph Hauke, Surinder K. Batra, Ming-Fong Lin

Journal Articles: Biochemistry & Molecular Biology

We examined the efficacy of combination treatments utilizing cytotoxic drugs plus inhibitors to members of the ErbB-ERK signal pathway in human prostate cancer (PCa) LNCaP C-81 cells. Under an androgen-reduced condition, 50nM gemcitabine caused about 40% growth suppression on C-81 cells. Simultaneous treatment of gemcitabine plus 10microM AG825 produced 60% suppression (p

Mcl-1 Degradation During Hepatocyte Lipoapoptosis., Howard C. Masuoka, Justin L. Mott, Steven F. Bronk, Nathan W. Werneburg, Yuko Akazawa, Scott H. Kaufmann, Gregory J. Gores

Journal Articles: Biochemistry & Molecular Biology

The mechanisms of free fatty acid-induced lipoapoptosis are incompletely understood. Here we demonstrate that Mcl-1, an anti-apoptotic member of the Bcl-2 family, was rapidly degraded in hepatocytes in response to palmitate and stearate by a proteasome-dependent pathway. Overexpression of a ubiquitin-resistant Mcl-1 mutant in Huh-7 cells attenuated palmitate-mediated Mcl-1 loss and lipoapoptosis; conversely, short hairpin RNA-targeted knockdown of Mcl-1 sensitized these cells to lipoapoptosis. Palmitate-induced Mcl-1 degradation was attenuated by the novel protein kinase C (PKC) inhibitor rottlerin. Of the two human novel PKC isozymes, PKCdelta and PKC, only activation of PKC was observed by phospho-immunoblot analysis. As compared with …

Pancreatic Cancer Cells Resistance To Gemcitabine: The Role Of Muc4 Mucin., S. Bafna, Sukhwinder Kaur, N. Momi, Surinder K. Batra

Journal Articles: Biochemistry & Molecular Biology

BACKGROUND: A major obstacle to the successful management of pancreatic cancer is to acquire resistance to the existing chemotherapeutic agents. Resistance to gemcitabine, the standard first-line chemotherapeutic agent for advanced and metastatic pancreatic cancer, is mainly attributed to an altered apoptotic threshold in the pancreatic cancer. The MUC4 transmembrane glycoprotein is aberrantly overexpressed in the pancreatic cancer and recently, has been shown to increase pancreatic tumour cell growth by the inhibition of apoptosis.

METHODS: Effect of MUC4 on pancreatic cancer cells resistance to gemcitabine was studied in MUC4-expressing and MUC4-knocked down pancreatic cancer cell lines after treatment with gemcitabine by …