Human BCL2L1 blocking peptide

Barrett's oesophagus (BO) and oesophageal adenocarcinoma (OAC) are regarded as complications of gastrooesophageal reflux disease, although all the factors that contribute to the development of these lesions are unknown. Acid suppressive drugs are widely used for symptomatic therapy of reflux disease but may induce hypersecretion of gastrin peptides. Amidated gastrin (G-17) has been shown to be a growth factor for OAC cells. We have examined the effects of glycine-extended gastrin (G-Gly), an alternative product of progastrin processing on apoptosis in the QhERT Barrett's oesophageal cell line and OE33 and BIC-1 OAC cells. G-Gly inhibited serum-starvation and camptothecin-induced apoptosis in all three cell lines, G-17 was only effective in OE33 cells. By contrast to the effects of G-17, the antiapoptotic effect of G-Gly was independent of both the CCK2 receptor and cyclo-oxygenase-2 activity. G-Gly stimulated JAK2 phosphorylation and kinase activity and JAK2-dependent STAT3 phosphorylation and transcriptional activity. G-Gly also increased mRNA and protein levels of the anti-apoptotic proteins survivin and BCL2L1 but did not affect the levels of BAD, BAX or BCL-2, Novel small molecule inhibitors of JAK2 and STAT3 as well as STAT3 siRNA blocked the anti-apoptotic effects of G-Gly and inhibited the induction of survivin and BCL2L1 in OE33 cells. We conclude that G-Gly inhibits apoptosis in BO and OAC via mechanisms distinct from those activated by G-17 and involving JAK2 and STAT3 activation. Release of gastrin peptides in response to acid suppressive therapy may adversely influence the dynamics of the epithelium in BO. Journal of Molecular Endocrinology (2009) 42, 305-318

Nur77, encoded by Nr4a1 (alias Nur77), plays rotes in cell death, survival, and inflammation. To study the role of Nur77 in liver regeneration, wild-type (WT) and Nur77 knockout (KO) mice were subjected to standard two-thirds partial hepatectomy (PH). Nur77 mRNA and protein levels were markedly induced at 1 hour after PH in WT livers, coinciding with ERK1/2 activation. Surprisingly, Nur77 KO mice exhibited a higher liver-to-body weight ratio than WT mice at 24, 48, and 72 hours after PH. Nur77 KO livers exhibited increase in Ki-67-positive hepatocytes at 24 hours, with early induction of cell-cycle genes. Despite accelerated regeneration, Nur77 KO livers paradoxically incurred necrosis, hepatocyte apoptosis, elevated serum aLanine aminotransferase activity, and Kupffer cell accumulation. Microarray analysis revealed upregulation of genes modulating inflammation, cell proliferation, and apoptosis but down-regulation (due to Nur77 deficiency) of glucose and lipid homeostasis genes. Levels of proinflammatory cytokines IL-6, IL-12, IL-23, and CCL2 were increased and levels of anti-inflammatory IL-10 were decreased, compared with WT. Activated NF-B-kappa and STAT3 and mRNA levels of target genes Myc and Bcl2l1 were elevated in Nur77 KO livers. Overall, Nur77 appears essential for regulating early signaling of Liver regeneration by modulating cytokine-mediated inflammatory, apoptotic, and energy mobilization processes. The accelerated liver regeneration observed in Nur77 KO mice is Likely due to a compensatory effect caused by injury.