Shugoshin 1 expression in various cancers: a potential target for therapy.

Shugoshin 1 (SGO1) is one of the Shugoshin (guardian spirit) family proteins, which is reported to be majorly involved in the protection of centromeres and proper segregation of chromosomes during cell division. Recent studies found that the altered expression of SGO1 is associated with various cancers and genetic disorders, and suggested as a target for therapy. In the present study, we have reviewed the available literature on SGO1 gene and protein expression in various cancer-cell lines, animal models and cancer patients, and targeting SGO1 with siRNA/shRNA. A significant increase in the expression of SGO1 mRNA and protein levels were observed in prostate, renal, lung, breast, neuroblastoma, leukemia, hepatocellular, and colon cancer-cell lines and the levels were associated with increased cellular proliferation, invasion, and metastasis. The altered SGO1 levels were observed in SGO1 knockout/haploinsufficient mice compared to wild type and the levels were associated with increased chromosome instability and tumorigenesis. Consistent with cell lines, higher SGO1 expression was also observed in tumor tissues of cancer patients compared to adjacent normal tissue and the levels were positively correlated with tumor stage, grade, size, and hormonal status. Higher SGO1 expression was related to resistance to chemotherapeutic agents and the knockdown of SGO1 increased sensitivity to those agents. Furthermore, targeting SGO1 with siRNA/shRNA reduced the expression of SGO1 and proliferation, and induced apoptosis of cancer cells. Overall, the SGO1 expression levels were significantly higher in various cancers, and targeting SGO1 with siRNA and shRNA reduced the levels of SGO1, proliferation and metastasis of cancers.