Expression of Transcription Factor FOXC2 in Cervical Cancer and Effects of Silencing on Cervical Cancer Cell Proliferation

Objective: Forkhead box C2 (FOXC2) is a member of the winged helix/forkhead box (Fox) family oftranscription factors. It has been suggested to regulate tumor vasculature, growth, invasion and metastasis,although it has not been studied in cervical cancer. Here, we analyzed FOXC2 expression in cervicaltissues corresponding to different stages of cervical cancer development and examined its correlation withclinicopathological characteristics. In addition, we examined the effects of targeting FOXC2 on the biologicalbehavior of human cervical cancer cells.
Methods: The expression of FOXC2 in normal human cervix, CIN I-IIIand cervical cancer was examined by immunohistochemistry and compared among the three groups and betweencervical cancers with different pathological subtypes. Endogenous expression of FOXC2 was transiently knockeddown in human Hela and SiHa cervical cells by siRNA, and cell viability and migration were examined by scratchand CCK8 assays, respectively.
Results: In normal cervical tissue the frequency of positive staining was 25%(10/40 cases), with a staining intensity (PI) of 0.297±0.520, in CIN was 65% (26/40cases), with a PI of 3.00±3.29,and in cancer was 91.8% (68/74 cases), with a PI of 5.568 ±3.449. The frequency was 100% in adenocarcinoma(5/5 cases) and 91.3% in SCCs (63/69 cases). The FOXC2 positive expression rate was 88.5% in patients withcervical SCC stage I and 100% in stage II, showing significant differences compared with normal cervix and CIN.With age, pathologic differentiation degree and tumor size, FOXC2 expression showed no significant variation.On transient transfection of Hela and SiHa cells, FOXC2-siRNA inhibition rates were 76.2% and 75.7%; CCK8results showed reduced proliferation and relative migration (in Hela cells from 64.5±3.16 to 49.5±9.24 and in SiHacells from 60.1±3.05 to 44.3±3.98) (P < 0.05).
Conclusion: FOXC2 gene expression increases with malignancy,especially with blood vessel hyperplasia and invasion degree. Targeted silencing was associated with reducedcell proliferation as well as invasion potential.