The Role of MEKK3 Signaling Pathway in the Resistance of Breast Cancer Cells to TNF-Alpha-Mediated Apoptosis
Annual summary rept. 1 May 2002-30 Apr 2006
M D ANDERSON CANCER CENTER HOUSTON TX
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To test the hypothesis that the MEKK3 regulated NF-kB and MAPK pathways may play a critical role in breast cancer growth and survival, we altered the regulation of MEKK3 pathway using dominant MEKK3 mutants and small interference RNA strategy. We used MEKK3 specific antibodies determining MEKK3 expression and activation in normal mammary gland cells and in breast cancer cells. We also developed an anti-active MEKK3 antibody that detects activated form of MEKK3. Using these reagents and assay systems, we found that although breast cancer cells express only slightly more MEKK3 than that in normal cells, the MEKK3 in the breast cancer cells appeared to be activated. In collaboration with Dr. J Yang s group in Baylor College of Medicine, we found the mekk3 locus was amplified in breast cancer cell line MCF7. In addition, we found that over expression of the exogenous MEKK3 in breast cancer cells induced cell apoptosis. In contrast, knock down mekk3expression led to a slower growth of breast cancer cells. However, stably knock down MEKK3 causing MCF7 cells to grow as a multiple layers and migrate slower that of control cells. Finally, we used Maldi-MS spectrometry technique and revealed a critical regulatory modification site in MEKK3 that was crucial for MEKK3 activation and function.
- Medicine and Medical Research