[Effects of CTCF on human liver cancer stem cells and cell proliferation].

Objective: To explore the effects of CCCTC-binding factor (CTCF) on human liver cancer stem cells (HepG2) and cell proliferation of HepG2 and Nasopharyngeal carcinoma cell line (CNE1).

Methods: The pEGFP-N1/CTCF, CTCF-shRNA and GFP-shRNA plasmids were constructed and transfected into HepG2 and CNE1 cells, and RT-PCR or Western blot were performed to detect the mRNA or protein levels of CTCF. The subpopulation of CD90+ cancer stem cells in HepG2 cells transfected with CTCF-shRNA plasmid or GFP-shRNA plasmid (as transfection control) were assayed by flow cytometry with the wild type HepG2 cells as control. Proliferation of cells transfected with CTCF-overexpression or CTCF-shRNA plasmid was evaluated by MTT assay.

Results: The levels of both mRNA and protein of CTCF were increased in pEGFP-N1/CTCF transfected HepG2 and CNE1 cells compared to that in pEGFP-N1 transfected cells (P < 0.05), and decreased in CTCF-shRNA transfected cells compared to that in cells transfected with GFP-shRNA (P < 0.05). The results of flow cytometry demonstrated that, detection rate of CD90+ cells in cells transfected with CTCF-shRNA plasmid [(1.7330 +/- 0.4177)%] was obviously higher than that of wild-type HepG2 cells [(0.5750 +/- 0.0629)%] and cells transfected with GFP-shRNA plasmid [(0.3500 +/- 0.0866)%] (P < 0.05). The results of MTT analysis showed that, alteration of CTCF had no effect on cancer cell proliferation (P > 0.05).

Conclusion: CTCF inhibits human liver cancer stem cells but no effect on cell proliferation.