Proteomic Profiling of β-hCG-Induced Spheres in BRCA1 Defective Triple Negative Breast Cancer Cells

Previously we identified that β-hCG is expressed by BRCA1 mutated but not wild type breast cancers in-vitro/in-vivo and exhibit a novel event in β-hCG over expressing BRCA1 mutated HCC1937cells where the cells were able to form spheres in adherent cell culture plates even in the absence of any growth factors. These spheres express stem cell and EMT markers. In the present study we carried out the total proteomic profiling of these HCC1937 β spheres obtained from BRCA1 defective β-hCG expressing stable breast cancer cells to analyze the cell signaling pathways that are active in these cells. Functional annotation revealed proteins (164 cellular and 97 secretory) predominantly involved in oxygen binding, nucleosome assembly, cytoskeleton organization, protein folding etc. Many of the proteins identified from HCC1937 β spheres in this study are also up regulated in breast cancers which are directly linked with poor prognosis in human cancer samples as analyzed using TCGA dataset. Survival analysis shows that...