[Relationship between MTA1 expression and invasive and metastatic ability of cervical cancer cell].

OBJECTIVE: To investigate the relationship between metastasis-associated gene 1 (MTA1) expression and invasive and metastatic ability of cervical cancer cell.

METHODS: Three kinds of plasmids pcDNA3 (control group), pcDNA3-MTA1 (MTA1 group) and pSilencer3.1-MTA1-siRNA (MTA1-siRNA group) were transfected into human cervical cancer cell line CaSki cells. Reverse transcription (RT)-PCR and western blot were used to detected MTA1 mRNA and protein expressions. The effects of MTA1 expression on CaSki cell growth and proliferation, cell migration, adhesion and invasion, and cell cycles were tested by methyl thiazolyl tetrazolium (MTT), clone formation experiment, wound-healing assay, transwell assay, adhesion assay and flow cytometry, respectively. In animal experiment, three groups of cells were inoculated to BALB/c nude mouse subcutaneously to observe tumor formation ability.

RESULTS: Compared with control group, MTA1 mRNA and protein were significantly overexpressed in MTA1 group, while MTA1-siRNA group showed lower MTA1 expression. Compared with control group, MTA1 group showed significantly accelerated cell growth; while MTA1-siRNA group showed decreased cell growth since the second day (P < 0.05). Clone formation number in control, MTA1 and MTA1-siRNA group were 133 ± 6, 169 ± 10 and 57 ± 5, respectively. MTA1 group showed accelerated cell formation, while MTA1-siRNA group showed the reverse effect compared with that in control group (P < 0.05). At 24, 48 and 72 hours after wounding, the healing ability of MTA1-siRNA group significantly lagged behind that in the control group, while MTA1 group showed accelerated cell healing ability. The adhesion rate of control, MTA1 and MTA1-siRNA group were (69.3 ± 3.6)%, (80.4 ± 5.6)% and (39.2 ± 7.4)% separately at 90 minutes after cell seeding. In contrast with control group, MTA1 group promoted the adhesion of CaSki cell to matrigel matrix, while MTA1-siRNA group inhibited the adhesion process (P < 0.05). In the migration assay, the number of cells migrated to the bottom side of the membrane in control, MTA1 and MTA1-siRNA group were 153 ± 17, 247 ± 38 and 82 ± 10, respectively. The number of cells in the invasion assay were 231 ± 19, 354 ± 36 and 76 ± 7, respectively. Compared with the control group, MTA1 group significantly increased the migration and invasion ability, while MTA1-siRNA group showed lower cell migration and invasion ability (P < 0.05). In cell cycle experiment, no significant differences of cell proportions including G(1), S and G(2) stage were found among three groups (P > 0.05). In animal experiment, compared with control group, MTA1 group showed accelerated tumor formation and growth, while the MTA1-siRNA group showed the reverse effect (P < 0.05).

CONCLUSIONS: MTA1 may play its roles to promote cervical cancer cell invasion, migration, adhesion, as well as cell growth and colony formation, while RNA interference against MTA1 may decrease the malignant phenotypes. This study shows that it will be an effective beginning to explore metastasis mechanisms and cancer gene therapy strategy targeting MTA1 in cervical cancer.