Medicine and Health Sciences Commons^™

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 …

Jnk1-Dependent Puma Expression Contributes To Hepatocyte Lipoapoptosis., Sophie C. Cazanave, Justin L. Mott, Nafisa A. Elmi, Steven F. Bronk, Nathan W. Werneburg, Yuko Akazawa, Alisan Kahraman, Sean P. Garrison, Gerard P. Zambetti, Michael R. Charlton, Gregory J. Gores

Journal Articles: Biochemistry & Molecular Biology

Free fatty acids (FFA) induce hepatocyte lipoapoptosis by a c-Jun N-terminal kinase (JNK)-dependent mechanism. However, the cellular processes by which JNK engages the core apoptotic machinery during lipotoxicity, especially activation of BH3-only proteins, remain incompletely understood. Thus, our aim was to determine whether JNK mediates induction of BH3-only proteins during hepatocyte lipoapoptosis. The saturated FFA palmitate, but not the monounsaturated FFA oleate, induces an increase in PUMA mRNA and protein levels. Palmitate induction of PUMA was JNK1-dependent in primary murine hepatocytes. Palmitate-mediated PUMA expression was inhibited by a dominant negative c-Jun, and direct binding of a phosphorylated c-Jun containing the …

Overexpression Of Mcl-1 Attenuates Liver Injury And Fibrosis In The Bile Duct-Ligated Mouse., Alisan Kahraman, Justin L. Mott, Steven F. Bronk, Nathan W. Werneburg, Fernando J. Barreyro, Maria E. Guicciardi, Yuko Akazawa, Karen Braley, Ruth W. Craig, Gregory J. Gores

Journal Articles: Biochemistry & Molecular Biology

Hepatocyte apoptosis contributes to liver injury and fibrosis after cholestatic injury. Our aim was to ascertain if the anti-apoptotic protein Mcl-1 alters liver injury or fibrosis in the bile duct-ligated mouse. Markers of apoptosis and fibrosis were compared in wild-type and transgenic mice expressing human Mcl-1 after bile duct ligation. Compared to hMcl-1 transgenic animals, ligated wild-type mice displayed a significant increase in TUNEL-positive cells and in caspase 3/7-positive hepatocytes. Consistent with apoptotic injury, the pro-apoptotic protein Bak underwent a conformational change to an activated form upon cholestatic injury, a change mitigated by hMcl-1 overexpression. Likewise, liver histology, number of …

Matrix Metalloproteinase Inhibitor, Cts-1027, Attenuates Liver Injury And Fibrosis In The Bile Duct-Ligated Mouse., Alisan Kahraman, Steven F. Bronk, Sophie Cazanave, Nathan W. Werneburg, Justin L. Mott, Patricia C. Contreras, Gregory J. Gores

Journal Articles: Biochemistry & Molecular Biology

Aim: Excessive matrix metalloproteinase (MMP) activity has been implicated in the pathogenesis of acute and chronic liver injury. CTS-1027 is an MMP inhibitor, which has previously been studied in humans as an anti-arthritic agent. Thus, our aim was to assess if CTS-1027 is hepato-protective and anti-fibrogenic during cholestatic liver injury. Methods: C57/BL6 mice were subjected to bile duct ligation (BDL) for 14 days. Either CTS-1027 or vehicle was administered by gavage. Results: BDL mice treated with CTS-1027 demonstrated a threefold reduction in hepatocyte apoptosis as assessed by the TUNEL assay or immunohistochemistry for caspase 3/7-positive cells as compared to vehicle-treated …

Death Receptor 5 Internalization Is Required For Lysosomal Permeabilization By Trail In Malignant Liver Cell Lines., Yuko Akazawa, Justin L. Mott, Steven F. Bronk, Nathan W. Werneburg, Alisan Kahraman, Maria Eugenia Guicciardi, Xue Wei Meng, Shigeru Kohno, Vijay H. Shah, Scott H. Kaufmann, Mark A. Mcniven, Gregory J. Gores

Journal Articles: Biochemistry & Molecular Biology

BACKGROUND & AIMS: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) cytotoxicity in hepatocellular carcinoma cells is mediated by lysosomal permeabilization. Our aims were to determine which TRAIL receptor, death receptor (DR) 4 or DR5, mediates lysosomal permeabilization and assess whether receptor endocytosis followed by trafficking to lysosomes contributes in this process.

METHODS: TRAIL ligand internalization in Huh-7 cells was examined by confocal microscopy using Flag-tagged TRAIL, whereas DR4- and DR5-enhanced green fluorescent protein internalization was assessed by total internal reflection microscopy. Clathrin-dependent endocytosis was inhibited by expressing dominant negative dynamin.

RESULTS: Although Huh-7 cells express both TRAIL receptors, short hairpin RNA …

Mitochondrial Fragmentation Is Involved In Methamphetamine-Induced Cell Death In Rat Hippocampal Neural Progenitor Cells., Changhai Tian, L. Charles Murrin, Jialin C. Zheng

Journal Articles: Pharmacology & Experimental Neuroscience

Methamphetamine (METH) induces neurodegeneration through damage and apoptosis of dopaminergic nerve terminals and striatal cells, presumably via cross-talk between the endoplasmic reticulum and mitochondria-dependent death cascades. However, the effects of METH on neural progenitor cells (NPC), an important reservoir for replacing neurons and glia during development and injury, remain elusive. Using a rat hippocampal NPC (rhNPC) culture, we characterized the METH-induced mitochondrial fragmentation, apoptosis, and its related signaling mechanism through immunocytochemistry, flow cytometry, and Western blotting. We observed that METH induced rhNPC mitochondrial fragmentation, apoptosis, and inhibited cell proliferation. The mitochondrial fission protein dynamin-related protein 1 (Drp1) and reactive oxygen …

Micrornas: Key Modulators Of Posttranscriptional Gene Expression., Steven P. O'Hara, Justin L. Mott, Patrick L. Splinter, Gregory J. Gores, Nicholas F. Larusso

Journal Articles: Biochemistry & Molecular Biology

No abstract provided.