Long non-coding RNA SAP30L-AS1 promotes prostate cancer growth through repressing SAP30L.

ABSTRACT

Accumulating evidences have demonstrated the importance of long non-coding RNAs (lncRNAs) in initiation and progression of various cancers, including prostate cancer. LncRNA SAP30L-AS1 is previously identified in the plasma of prostate cancer patients. In this study, we further investigated the expression of SAP30L-AS1 in prostate cancer tissues and cell lines. Moreover, we explored the biological roles and mechanisms of action of SAP30L-AS1 in prostate cancer. The expression of SAP30L-AS1 is found to be increased in prostate cancer tissues and cell lines compared with adjacent noncancerous tissues and normal prostate epithelial cell line, respectively. Increased expression of SAP30L-AS1 is associated with greater Gleason score, advanced pathological T stage, and poor over survival of prostate cancer patients. Functional assays demonstrated that ectopic expression of SAP30L-AS1 promotes prostate cancer proliferation and inhibits prostate cancer apoptosis. SAP30L-AS1 knockdown represses prostate cancer proliferation and induces prostate cancer apoptosis. Furthermore, SAP30L-AS1 knockdown represses prostate cancer xenograft growth in vivo. Mechanistic investigation revealed that SAP30L-AS1 physically binds to the promoter of SAP30L and represses SAP30L expression. The expression of SAP30L is negatively associated with that of SAP30L-AS1 in prostate cancer tissues. Rescue assays demonstrated that overexpression of SAP30L attenuated the roles of SAP30L-AS1 in promoting prostate cancer proliferation and inhibiting prostate cancer apoptosis. In conclusion, SAP30L-AS1 is upregulated and has oncogenic roles in prostate cancer via repressing SAP30L. Our data suggest that SAP30L-AS1 may be a promising prognostic biomarker and therapeutic target for prostate cancer.