[Effects of PPARγ gene expression on cell migration, invasion, and proliferation in endometrial cancer cells].

OBJECTIVE: To observe the effects of differentially expressed peroxisome proliferator-activated receptor γ (PPARγ) on cell migration, invasion and proliferation of endometrial cancer cells.

METHODS: Two endometrial cancer cell lines ECC-1 (ER positive) and KLE (ER negative) cells were used in this study. To up or down regulate PPARγ expression, the transient transfection by using PPARγ expression vector (PPARγ expression vector group) and PPARγ small interference RNA (PPARγ siRNA group) were done. The negative control groups were cells transfected by nonsence sequence siRNA (siRNA nonsence sequence group) or empty vector (empty vector group). At the same time, cells only added with liposome were used as blank control group. Then, quantitative real time (RT) -PCR and western blot were used to detect PPARγ expression both in mRNA and protein levels. To assess the expression levels of Wnt signaling pathway, western blot was performed to analysis protein levels of β-catenin and C-myc. The effects on cell migration, invasion and proliferation using in vitro transwell migration, invasion assays and cell counting kit-8 (CCK-8) assay were further be examined.

RESULTS: After transfection for 48 hours, quantitative RT-PCR and western blot showed that PPARγ mRNA(5.18 ± 0.99, 4.54 ± 0.89) and protein (1.45 ± 0.12, 1.30 ± 0.13) expression levels significantly increased and the protein levels of β-catenin (0.44 ± 0.06, 0.46 ± 0.04) and C-myc (0.42 ± 0.08, 0.30 ± 0.11) decreased in PPARγ expression vector group, while in PPARγ siRNA group, PPARγ mRNA(0.48 ± 0.08, 0.53 ± 0.11) and protein (0.41 ± 0.04, 0.49 ± 0.05) expression levels decreased and the protein levels of β-catenin (1.18 ± 0.12, 0.89 ± 0.07) and C-myc (0.91 ± 0.08, 0.77 ± 0.12) increased significantly compared with control groups (all P < 0.05) . In vitro migration and invasion assay indicated that the migratory and invasive cell numbers of PPARγ expression vector group (ECC-1:129 ± 9, 63 ± 12; KLE:119 ± 9, 68 ± 16) were significantly decreased, while the migratory and invasive cell numbers of were PPARγ siRNA group (ECC-1:201 ± 14, 142 ± 9; KLE:170 ± 11, 138 ± 7) increased significantly compared with those in control groups (all P < 0.05). CCK-8 assay showed that A values (0.66 ± 0.14, 0.78 ± 0.06) in PPARγ expression vector group were lower than those in control groups, and in PPARγ siRNA group, A values (1.42 ± 0.16, 1.23 ± 0.04) were higher than those in control groups, and there were statistically significant difference among them (all P < 0.05).

CONCLUSION: Up-regulated PPARγ gene expression could inhibit endometrial cancer cell migration, invasion and proliferation abilities, and down-regulated PPARγ gene expression could promote endometrial cancer cell migration, invasion and proliferation abilities.