Effects Of The Interference Of GIPC1 On Protein Expression In MCF-7 Breast Cancer Cells

Breast cancer is the most frequently diagnosed cancer in women. With the cancer stem cell concept introducted and solid tumor cancer stem cells isolated, it is known that cancer stem cells are playing a key role in the tumorigenesis and progression of cancer. We have successfully cultured mammosphere within MCF-7 cell line, and identified 34 differentially expressed proteins in mammosphere among which GIPC1 was highly expressed from parental cells via protomics analysis.GIPC1 is a scaffolding protein that regulates cell surface receptor expression and trafficking. We have generated GIPC1 knockdown cells lines GIPC1-i2 via lentivirus which can transcribe a short hairpin RNA against GIPC1. The interfection result was confirmed by western bolt. With mammosphere cultured both in GIPC1 stably low-expressed cell lines and control cell lines, it seems that the low expressing level of GIPC1 does not effect the shape or growth of mammosphere.Using 2-dimension electrophoresis and Mass Spec, we have identified 11 differentially expressed proteins in GIPC1 knockdown cells compared to negtive control cells, which contains cytoskeletal protein, signal-transducing protein and metabolism relevant proteins and so on. Lamin A is one of eight high-expression protein in the GIPC-i2 cells. It is ascribed a key role in the regulation of DNA replication, cell-cycle progression and apoptosis. Patients with lamin A-positive tumors which has been proved to be a putative colonic epithelial stem cell biomarker were almost twice as likely to suffer CRC-related death. So, it is interesting and meaningful to do a further study to find the influence of lamin A in the occurrence and formation of memmosphere.