Archana Verma

Selenomethionine Stimulates MAPK (ERK) Phosphorylation, Protein Oxidation, and DNA Synthesis in Gastric Cancer Cells

Abstract: Selenium is an essential trace element and is required for the synthesis of cellular enzymes that protect against oxidative stress. Epidemiological findings indicate that low selenium intake is associated with increased cancer risk, and, although the majority of studies show that exposure of transformed cells to selenium results in apoptotic cell death, there are reports indicating that cells exposure to low selenium concentrations promotes cellular proliferation. Gastric adenocarcinoma SNU-1 cells responded to selenomethionine with a biphasic proliferative curve: enhanced incorporation of 3H-thymidine into DNA within a very narrow range of selenomethionine concentrations followed by decreased 3H-thymidine uptake at higher levels. Concentrations of selenomethionine that stimulate cellular proliferation also induce cellular oxidation and phosphorylation of MAPK (ERK), a component of cell signaling cascades. MAPK (ERK) phosphorylation is synonymous with MAPK activation and enhanced cell growth. Our findings support previous observations of enhanced proliferation in response to low levels of selenium and suggest that, at certain concentrations, selenomethionine induces mild oxidative stress that, in turn, stimulates DNA synthesis.

Antioxidants up-regulate PPAR|[gamma]| and decrease fibrosis in chronic pancreatitis

Purpose: Pancreatic fibrosis results from repeated episodes of inflammation and chronic oxidative stress within the pancreas. PPAR is a ligand-activated transcription factor that modulates inflammation in different tissues, and has been shown to block activation of pancreatic stellate cells in vitro.The aim of this study was to investigate the antifibrotic/anti-inflammatory effect of the antioxidants, vitamin C and vitamin E, in chronic pancreatitis.

New approach in the management of proximally migrated stent with an obstructing anti-reflux valve

New approach in the management of proximally migrated stent with an obstructing anti-reflux valve