Interaction of the MUC1 Tumor Antigen and the Adenomatous Polyposis Coli Tumor Suppressor in Human Breast Cancer
Annual summary rept. 23 Feb 2004-22 Feb 2005
MAYO CLINIC SCOTTSDALE AZ
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This project examines the interaction of MUC1, a breast tumor antigen, with APC, a potent tumor suppressor. We have focused on Task 4 in the approved Statement of Work To clarify the functional significance of the interaction in relation to b-catenin and ErbB signaling. TO this end, we have determined that APC most likely interacts preferentially with wildtype MUC1 as compared to a MUC1 mutant lacking tyrosines in the cytoplasmic tail. We have created several constructs to overcome difficulties associated with poor APC antibodies His exp-6 and myc-tagged, as well as constructs for tandem affinity purification TAP and fluorescence resonance energy transfer FRET. We have expressed APC in breast cell lines under a zinc-inducible promoter, but have determined that these cells are too inconsistent to use for immunoprecipitations. In another breast cancer cell lines, MDA-MB-468, we have successfully knocked down MUC1 expression using siRNA technology interestingly, the reduced level of MUC1 correlated with a decrease in active b-catenin in these cells. Our upcoming studies will make use of TAP, FRET, and siRNA as complementary assays in examining the role of the MUC1-APC interaction in human breast cancer.
- Medicine and Medical Research