puma creepers

ÿþSimilar to the PUMA down-regulation, over-expression of EGFRvIII in U87MG cells puma creepers resulted in significant resistance to anisomycin-induced apoptosis ( Fig. 3c,d ). After treatment with anisomycin, there was only 3.1% apoptosis in U87MG-EGFRvIII cells. In contrast, the isogenic low EGFR expressing U87MG-vector cells underwent massive apoptosis (49.8%), similar to the level observed with PUMA down-regulation (45.5%). The results in Fig.

3 , collectively, indicate that GBM apoptosis is positively regulated by PUMA and negatively impacted by EGFR/EGFRvIII, suggesting that PUMA and EGFR/EGFRvIII pathways are functionally but inversely linked to apoptosis in GBM cells.The results in Fig. 4 indicate that, in puma fenty GBM cells, EGFR/EGFRvIII and PUMA form complex constitutively under unstressed conditions and that the complex is sustained even following treatment with the apoptosis-inducer, staurosporin (ST).

The mitochondrial fractionation/western blotting ( Fig. 5a ) showed puma slides PUMA to be primarily localized in the non-mitochondrial fractions of U87MG-EGFRvIII cells under unstressed condition and to undergo a modest mitochondrial translocalization following exposure to the apoptotic inducers, staurosporin (ST) and anisomycin (AN). As indicated by the low mtPUMA index (0-0.02), the majority of PUMA is sequestered in the non-mitochondrial fractions of the EGFRvIII-expressing U87MGEGFRvIII cells ( Fig. 5a ).

The mtPUMA indices in these cells are puma rihanna 1.0, indicating that PUMA is exclusively detected on the mitochondria of these cells, independent of apoptotic stress. (C) EGFR expression knockdown by siRNA leads to increased PUMA mitochondrial translocalization. In control siRNA-treated T98G natural GBM cells, PUMA is primarily localized in the cytoplasm. In EGFR-specific siRNA-treated cells, we observed a marked increase of mitochondrial PUMA (left panel).

Importantly, siRNA-mediated EGFR expression knockdown led to a significant increase (16-fold) of mitochondrial PUMA ( Fig. 5c-left ), further suggesting the ability of EGFR to modulate PUMA mitochondrial translocalization. EGFR-specific siRNA was effective in reducing EGFR expression as shown by the western puma suede classic blots ( Fig. 5c-right ). In addition to GBM cells, we found PUMA to be localized in the cytoplasm of MDA-MB-468 human breast cancer cells .

To further determine whether EGFR kinase activity is required for the EGFR-PUMA interaction, we treated U87MG-EGFR cells with a small molecular weight EGFR kinase inhibitor, Iressa, that is in clinical use to inhibit EGFR activity. As shown by Fig. 6b (left panel) , Iressa did not alter EGFR binding to PUMA but, as expected, significantly reduced the level of EGFR auto-phosphorylation/activation.EGFR-PUMA interaction is independent of [img]http://www.czcrush.com/images/detail/puma suede classic-642law.jpg[/img] ligand-mediated receptor activation and is sustained under EGFR inhibition.