microRNA-577 suppresses tumor growth and enhances chemosensitivity in colorectal cancer. 
In this work, we aimed to determine the expression and biological functions of microRNA (miR)-577 in colorectal cancer (CRC).  The results showed that miR-577 was downregulated in CRC specimens and cell lines.  Restoration of miR-577 significantly suppressed the proliferation and colony formation and induced a G0/G1 cell cycle arrest in CRC cells.  5-Fluorouracil (5-FU)-resistant SW480 cells (SW480/5-FU) were found to have elevated levels of miR-577.  Ectopic expression of miR-577 enhanced 5-FU sensitivity in SW480/5-FU cells.  Heat shock protein 27 (HSP27) was identified as a target gene of miR-577.  Enforced expression of HSP27 reversed the effects of miR-577 on CRC cell growth and 5-FU sensitivity.  Xenograft tumors derived from miR-577-overexpressing SW480 cells exhibited significantly slower growth than control tumors.  In conclusion, our results support that miR-577 acts as a tumor suppressor in CRC likely through targeting HSP27.  Therefore, miR-577 may have therapeutic potential in the treatment of CRC.