Effect Of TCF4on The Biological Behavior Of Human Squamous Carcinoma A431Cell Lines

Backgrounds and ObjectivesSquamous-cell carcinoma (SCC) is a cancer of malignant skin tumors originated fromthe epidermis and cutaneous adnexal keratinocytes, with high rates of growth, malignancy,local recurrence and distant metastasis. However, the mechanism of SCC is currentlyunclear. Wnt/β-catenin (canonical Wnt) signaling is involved in a broad range of biologicalsystems, including biological structure formation, cell differentiation, morphogenesis andtumor progression. In the body part with a tumor, the metabolism balance of β-catenindisorders, hypophosphorylated β-catenin accumulates in the cytoplasm and is able totranslocate to the nucleus, where it interacts with T cell factor/lymphoid enhancer factor(TCF/LEF) to activate the downstream gene transcription, and recruit positive co-factors toactivate transcription of Wnt target genes, resulting in increasing possibility oftumorigenesis. TCF/LEF is a group protein (High Mobility Group, HMG) of highlyconserved high mobility. It is a nuclear transcription factor, whose members include TCF-1,LEF1, TCF-3and TCF-4. Among them, TCF-4is the most important transcription factorassociated with tumor, which has been proved by the studies in recent years.Recent studies indicated that TCF4is highly expressed on the occurrence of lungcancer, renal carcinoma, colon carcinoma, gastric cancer and liver cancer, abnormalexpression of TCF4activating transcription of Wnt target genes is the early common eventsin the tumorigenesis of these cancers. Inhibitors targeting β-catenin/TCF can inhibit tumorgrowth, proliferation, invasion and migration. In present study, we aimed to investigate theeffect of TCF4on the biological behavior of human squamous carcinoma A431cell lines,which will help to indicate the role of Wnt/β-catenin (canonical Wnt) signaling in SCC,then open new avenues for novel and tailor-made cancer therapeutic approaches.Experimental methods and results1. A431cell lines were transfect with control siRNA and si-TCF4RNA Liposome using the siRNA expression technology, then the total RNA was extracted for subsequentexperiment.2. RT-PCR technology was used to detect changes of TCF4mRNA expression inA431cells before and after transfect of si-TCF4.3. A431cell protein was extracted and Western blotting was used to detect theexpression changes of cells TCF4protein after the transfect of si-TCF4.4. Transwell method was used to observe the changes of invasion and migrationactivities of A431cells after transfect of si-TCF4.5. CCK-8method was used to observe the changes of proliferation activities of A431cells after transfect of si-TCF4.6. Flow cytometry was used to analyze the changes of cell cycle of A431cells aftertransfect of si-TCF4.7. Test was randomized as non transfect group, transfect control siRNA group andsi-TCF4group. The results showed that, compared with the non transfect group and transfectcontrol siRNA group, transfect si-TCF4effectively down regulated the expression level ofTCF4mRNA and protein in A43l cells. After the inhibition of TCF4, the migration andinvasion abilities of cells decreased significantly (P <0.05), and the abilities of cell growth andproliferation were also inhibited (P <0.05). In addition, analysis of cell cycle demonstrated amarked blockage of the G2/M stage of the A431cells treated with TCF4siRNA.Conclusion1. The si-TCF4can inhibit the expression of TCF4mRNA and protein in skinsquamous cell carcinoma A431cell lines.2. The TCF4can promote the proliferation, migration and invasion activities of A431cell in the skin squamous cell carcinoma..3. After the inhibition of TCF4, the ability of cell growth of A431cells can beinhibited.Above experiment will lay the foundations for the further understanding of regulationmechanism of Wnt/β-catenin signaling in SCC, and the TCF4gene can be used as potentialtargets for clinical therapy of SCC.