Identification of Translocon-associated Protein Delta as An Oncogene in Human Colorectal Cancer Cells

Identifying the roles of genes in cancer is critical in discovering potential genetic therapies for cancer care. Translocon-associated protein delta (TRAPδ), also known as signal sequence receptor 4 (SSR4), is a constituent unit in the TRAP/SSR complex that resides in the endoplasmic reticulum and plays a key role in transporting newly synthesized proteins into the endoplasmic reticulumn. However, its biological role in disease development remains unknown to date. This is the first study to identify the role of TRAPδ/SSR4 in colorectal cancer cells in vitro. Upon successful transient knockdown of TRAPδ/SSR4, we observed significant reduction of cell viability in all colorectal cancer cell lines tested. Both HCT 116 and SW480 cell lines were significantly arrested at S and G1 phases, while DLD-1 cells were significantly apoptotic. Moreover, TRAPδ/SSR4 stable knockdown HCT 116 and SW480 cells showed significantly lower viability, anchorage-independent growth, and increased S and G1 phase arrests. Overall, we conclude TRAPδ/SSR4 is a potential oncogene in human colorectal cancer cells.