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HMG I(Y) is a determinant of pancreatic adenocarcinoma cellular invasiveness
Vol. 201, No. 3S, September 2005
salvamide A, the product of a marine fungus, are potential anticancer agents. We hypothesized these peptides would inhibit human pancreatic cancer cell growth in vitro. METHODS: Two human pancreatic cancer cell lines (AsPC-1 and S2-013) were treated with varying concentrations (0.1-100mcM) of peptide. Proliferation was measured by 3H-thymidine incorporation and cell counting at different time points (24-72h). Cell cycle analysis was determined by flow cytometry with propidium iodide DNA staining. Cell cycle-associated proteins were investigated by western blotting. Apoptosis was confirmed by annexin-binding assays. RESULTS: The peptides caused both time- and concentrationdependent inhibition of DNA synthesis (46% decrease in AsPC-1 at 24 hours with 1mcM, p⬍0.01) and cell proliferation (93% decrease in AsPC-1 at 72 hours with 10mcM, p⬍0.01) with similar results in both cell lines. The peptides induced G0/G1 phase cell cycle arrest similarly in both cell lines (S2-013 control 55.8% vs treated 75.9%, p⬍0.002). The peptides reduced levels of cyclin E and cdk2, and induced expression of p21, proteins involved in regulation of G0/G1 transition. The peptides increased the number of apoptotic cells in both cell lines (AsPC-1 control 5.6% vs peptides 20.6%, p⫽0.03). CONCLUSIONS: These novel peptides induce apoptosis and inhibit growth of pancreatic cancer cells through induction of p21/waf1, suppression of cyclin E-associated cdk2 activity, and G0/G1 arrest. These peptides may be valuable for the treatment of pancreatic cancer.
NMR detectable cholesterol is an early marker of tumor response to cytotoxic chemotherapy in colon cancer xenografts Peter T Kennealey MD, Elliot B Sambol MD, Penelope DeCarolis BS, Rula C Geha MD, Yuhong She MD, Gary K Schwartz MD, Jin-Hong Chen PhD, Samuel Singer MD, FACS Memorial Sloan-Kettering Cancer Center, New York NY INTRODUCTION: We have previously shown that NMR detectable cholesterol is a sensitive marker for drug induced apoptosis in HCT-116 cells. Here we demonstrate that NMR detectable cholesterol is an early predictor of chemotherapeutic efficacy in a mouse xenograft model of human colon cancer. METHODS: Athymic nude mice were inoculated on both flanks with HCT-116 cells an then treated according to the following schedule: vehicle alone, CPT-11: 25, 50 or 75mg/kg. Treatments were administered 2x/week for 5 cycles and tumor volume was assessed every third day for 30 days. Tumors from the left flank were harvested 48hrs after the second treatment and examined by NMR; tumors on the right flank were allowed to progress through the entire treatment course. RESULTS: Treatment of these tumor bearing mice with 25, 50, and 75 mg/kg of CPT-11 results in a respective 2.25 (p⫽0.003), 2.8 (p⫽0.001), and 3.3 (p⫽0.0003) fold increase in NMR detectable cholesterol when compared to untreated controls. This corresponds to a respective 63%, 79% and 95% decrease in tumor volume at day 31. Furthermore, there is a stepwise, qualitative rise in caspase staining of harvested tumor samples with escalating doses of CPT-11.
Surgical Oncology I
S81
CONCLUSIONS: NMR visible cholesterol is an early, accurate, quantitative predictor of tumor response to cytotoxic chemotherapy in this colon cancer xenograft model system. Implementation of this technology in the clinical setting may enable identification of patients likely to respond to chemotherapy early in their treatment course before significant measurable changes in tumor size become evident.
HMG I(Y) is a determinant of pancreatic adenocarcinoma cellular invasiveness Siong-Seng Liau MBChB, MRCSEd, Eric Benoit MD, Stanley Ashley MD, FACS, Edward Whang MD, FACS Brigham and Women’s Hospital, Boston, MA INTRODUCTION: Pancreatic adenocarcinoma has an overtly invasive phenotype. The high mobility group I protein family members [HMG I(Y)] have been implicated in the malignant phenotype of a range of cancers. More specifically, overexpression of HMG I(Y) has been associated with tumor metastasis. HMG I and HMG Y proteins represent two alternatively-spliced proteins which differ by 11 amino acids and are encoded by the same gene. HMG I(Y) proteins are non-histone nuclear proteins, which bind the AT-rich regions in the minor groove of DNA via three AT-hook domains. They play an important role in regulating gene expression by acting as architectural nuclear proteins. We hypothesize that HMG I(Y) promotes pancreatic adenocarcinoma cellular invasiveness. METHODS: We studied pancreatic adenocarcinoma cell line PANC1, which is known to overexpress HMG I(Y). RNA interference was used to silence HMG I(Y) expression. Cellular invasiveness was quantified using modified Boyden chamber assay. Knock-down of HMG I(Y) expression was confirmed using Western blot analysis at 48 hours after siRNA transfection. RESULTS: We achieved 67% silencing of HMG I(Y) protein expression when compared to control siRNA group [relative density (normalized to actin): siHMG I(Y) vs. siControl;1.00⫹/-0.03 vs. 3.03⫹/-0.75 arbitrary units,p⬍0.05]. siHMG I(Y) transfected cells showed significantly lower invasive capacity; 2.5-fold lower compared to control siRNA group (relative invasion:1.0⫹/-0.8 vs. 2.5⫹/-1.5 arbitrary units,p⫽0.02). There was no significant effect on cellular migration. CONCLUSIONS: HMG I(Y) expression is a determinant of pancreatic adenocarcinoma cellular invasiveness. HMG I(Y) may represent a novel therapeutic target for pancreatic cancer, warranting further investigations.
Paradoxical effect of proteasome inhibition on beta-catenin expression in apc-mutant and betacatenin mutant human colon cancer cells Christopher J Smolock MD, James Pippin BA, Randall Scheri MD, Jeffrey Drebin MD, PhD, FACS University of Pennsylvania School of Medicine, Philadelphia, PA INTRODUCTION: Molecular abnormalities involving the adenomatous polyposis coli (APC) or beta-catenin genes occur in most
salvamide A, the product of a marine fungus, are potential anticancer agents. We hypothesized these peptides would inhibit human pancreatic cancer cell growth in vitro. METHODS: Two human pancreatic cancer cell lines (AsPC-1 and S2-013) were treated with varying concentrations (0.1-100mcM) of peptide. Proliferation was measured by 3H-thymidine incorporation and cell counting at different time points (24-72h). Cell cycle analysis was determined by flow cytometry with propidium iodide DNA staining. Cell cycle-associated proteins were investigated by western blotting. Apoptosis was confirmed by annexin-binding assays. RESULTS: The peptides caused both time- and concentrationdependent inhibition of DNA synthesis (46% decrease in AsPC-1 at 24 hours with 1mcM, p⬍0.01) and cell proliferation (93% decrease in AsPC-1 at 72 hours with 10mcM, p⬍0.01) with similar results in both cell lines. The peptides induced G0/G1 phase cell cycle arrest similarly in both cell lines (S2-013 control 55.8% vs treated 75.9%, p⬍0.002). The peptides reduced levels of cyclin E and cdk2, and induced expression of p21, proteins involved in regulation of G0/G1 transition. The peptides increased the number of apoptotic cells in both cell lines (AsPC-1 control 5.6% vs peptides 20.6%, p⫽0.03). CONCLUSIONS: These novel peptides induce apoptosis and inhibit growth of pancreatic cancer cells through induction of p21/waf1, suppression of cyclin E-associated cdk2 activity, and G0/G1 arrest. These peptides may be valuable for the treatment of pancreatic cancer.
NMR detectable cholesterol is an early marker of tumor response to cytotoxic chemotherapy in colon cancer xenografts Peter T Kennealey MD, Elliot B Sambol MD, Penelope DeCarolis BS, Rula C Geha MD, Yuhong She MD, Gary K Schwartz MD, Jin-Hong Chen PhD, Samuel Singer MD, FACS Memorial Sloan-Kettering Cancer Center, New York NY INTRODUCTION: We have previously shown that NMR detectable cholesterol is a sensitive marker for drug induced apoptosis in HCT-116 cells. Here we demonstrate that NMR detectable cholesterol is an early predictor of chemotherapeutic efficacy in a mouse xenograft model of human colon cancer. METHODS: Athymic nude mice were inoculated on both flanks with HCT-116 cells an then treated according to the following schedule: vehicle alone, CPT-11: 25, 50 or 75mg/kg. Treatments were administered 2x/week for 5 cycles and tumor volume was assessed every third day for 30 days. Tumors from the left flank were harvested 48hrs after the second treatment and examined by NMR; tumors on the right flank were allowed to progress through the entire treatment course. RESULTS: Treatment of these tumor bearing mice with 25, 50, and 75 mg/kg of CPT-11 results in a respective 2.25 (p⫽0.003), 2.8 (p⫽0.001), and 3.3 (p⫽0.0003) fold increase in NMR detectable cholesterol when compared to untreated controls. This corresponds to a respective 63%, 79% and 95% decrease in tumor volume at day 31. Furthermore, there is a stepwise, qualitative rise in caspase staining of harvested tumor samples with escalating doses of CPT-11.
Surgical Oncology I
S81
CONCLUSIONS: NMR visible cholesterol is an early, accurate, quantitative predictor of tumor response to cytotoxic chemotherapy in this colon cancer xenograft model system. Implementation of this technology in the clinical setting may enable identification of patients likely to respond to chemotherapy early in their treatment course before significant measurable changes in tumor size become evident.
HMG I(Y) is a determinant of pancreatic adenocarcinoma cellular invasiveness Siong-Seng Liau MBChB, MRCSEd, Eric Benoit MD, Stanley Ashley MD, FACS, Edward Whang MD, FACS Brigham and Women’s Hospital, Boston, MA INTRODUCTION: Pancreatic adenocarcinoma has an overtly invasive phenotype. The high mobility group I protein family members [HMG I(Y)] have been implicated in the malignant phenotype of a range of cancers. More specifically, overexpression of HMG I(Y) has been associated with tumor metastasis. HMG I and HMG Y proteins represent two alternatively-spliced proteins which differ by 11 amino acids and are encoded by the same gene. HMG I(Y) proteins are non-histone nuclear proteins, which bind the AT-rich regions in the minor groove of DNA via three AT-hook domains. They play an important role in regulating gene expression by acting as architectural nuclear proteins. We hypothesize that HMG I(Y) promotes pancreatic adenocarcinoma cellular invasiveness. METHODS: We studied pancreatic adenocarcinoma cell line PANC1, which is known to overexpress HMG I(Y). RNA interference was used to silence HMG I(Y) expression. Cellular invasiveness was quantified using modified Boyden chamber assay. Knock-down of HMG I(Y) expression was confirmed using Western blot analysis at 48 hours after siRNA transfection. RESULTS: We achieved 67% silencing of HMG I(Y) protein expression when compared to control siRNA group [relative density (normalized to actin): siHMG I(Y) vs. siControl;1.00⫹/-0.03 vs. 3.03⫹/-0.75 arbitrary units,p⬍0.05]. siHMG I(Y) transfected cells showed significantly lower invasive capacity; 2.5-fold lower compared to control siRNA group (relative invasion:1.0⫹/-0.8 vs. 2.5⫹/-1.5 arbitrary units,p⫽0.02). There was no significant effect on cellular migration. CONCLUSIONS: HMG I(Y) expression is a determinant of pancreatic adenocarcinoma cellular invasiveness. HMG I(Y) may represent a novel therapeutic target for pancreatic cancer, warranting further investigations.
Paradoxical effect of proteasome inhibition on beta-catenin expression in apc-mutant and betacatenin mutant human colon cancer cells Christopher J Smolock MD, James Pippin BA, Randall Scheri MD, Jeffrey Drebin MD, PhD, FACS University of Pennsylvania School of Medicine, Philadelphia, PA INTRODUCTION: Molecular abnormalities involving the adenomatous polyposis coli (APC) or beta-catenin genes occur in most