SCC-S2 is overexpressed in colon cancers and regulates cell proliferation

SCC-S2 was recently reported to be overexpressed in various cancers and associated with the malignant behavior of cancer cells. However, the expression of SCC-S2 and its biological roles in colon cancers have not been reported. The aim of this study is to investigate the expression and clinical significance of SCC-S2 in colon cancers and explore its biological function in colon cancer cells. We analyzed the expression pattern of SCC-S2 in 92 colon cancer tissues by immunohistochemistry and found that SCC-S2 was overexpressed in 45 (48.9 %) of 92 colon cancer specimens. There was a significant association between SCC-S2 overexpression and TNM stage (p = 0.0387), lymph node metastasis (p = 0.0219), and proliferation index (p = 0.0279). siRNA knockdown of SCC-S2 expression in CACO2 and HCT116 cells decrease cell proliferation, colony formation, and soft agar colony formation ability. Furthermore, western blot analysis showed that SCC-S2 depletion decreased cyclin D1 and phospho-Rb levels. In conclusion, we demonstrated that SCC-S2 is overexpressed in colon cancers and contributes to malignant cell growth by cyclin D1 and phospho-Rb modulation, which makes SCC-S2 a candidate therapeutic target in colon cancer.