UHRF1 promotes cell growth and metastasis through repression of p16(ink⁴a) in colorectal cancer.

PURPOSE: To investigate whether ubiquitin-like with plant homeodomain and ring finger domains 1 (UHRF1) expression is upregulated in colorectal cancer (CRC), whether UHRF1 promotes CRC cell growth and migration and the underlying molecular mechanism.

METHODS: UHRF1 protein expression was determined in 144 pairs of primary CRC and their corresponding adjacent nontumor tissues by immunohistochemistry with tissue microarrays. UHRF1 mRNA expression was assessed in 20 pairs of the above tissues and four colon cancer cell lines by quantitative reverse transcriptase-polymerase chain reaction. Associations of UHRF1 expression with demographic and clinicopathologic features were determined. Additionally, the effects of lentiviral-mediated RNA interference (RNAi) of UHRF1 on cell proliferation and migration, cell cycle and apoptosis, and the expression of p16(ink4a) and p21(waf1/cip1) were investigated in CRC cell lines.

RESULTS: UHRF1 was overexpressed in CRC tissues and cell lines. UHRF1 protein expression levels correlated with the presence of lymph nodes (P = 0.005), distal metastasis (P = 0.030), poor Dukes staging (P = 0.001), and absence of p16(ink4a) expression (P = 0.002). RNAi of UHRF1 inhibited proliferation and migration, and induced apoptosis and cell cycle arrest at the G0/G1 phase. Furthermore, RNAi of UHRF1 enhanced the expression of p16(ink4a), but not p21(waf1/cip1), in CRC cells.

CONCLUSIONS: UHRF1 expression is upregulated in CRC and is associated with the progression of CRC. Moreover, RNAi of UHRF1 decreases proliferation and migration but enhances apoptosis of CRC cells, with increased p16(ink4a) expression. UHRF1 promotes CRC growth and metastasis, likely by repressing p16(ink4a), and thus it may be used as a biomarker or even a therapeutic target for CRC.