The Effect Of Over Expression Of FHIT Gene On The Biological Properties Of Muco-epidermoid Carcinoma Cell Line

Mucoepidermoid carcinoma is the most common malignance of salivary gland, and comprises of about 30% malignant tumors of salivary gland. Mucoepidermoid carcinoma often metastasizes to lymphnode and lung. At present, mucoepidermoid carcinoma is treated with synthetic treatment of operation, radiation and chemotherapy. The results of the treatments are not ideal. The recurrence of mucoepidermoid carcinoma with the low differentiation is up to 60-70%, and the survival rate of the patients is less than 17%. Therefore, it is necessary to find new way for the treatment. In view that the location of parotid gland is shallow, carcinomain the gland is especially fit for gene therapy.The FHIT gene, first isolated by exon trapping and positional cloning in 1996, encompasses the normal human chromosomal fragile site 3p14.2 and contains 10 exons. Exons 5 to 9 form an "open reading frame", which encodes 147 amino acids, Fhit protein. Since FHIT gene has been investigated extensively in many human epithelial cancers, such as lung small cell carcinoma, head and neck squamous cell carcinoma, cervical, breast, digestive tract cancers, etc., and in related cell lines. The abnormal transcription and homozygous loss or alleles was observed in most cancers. To determine the function of the FHIT gene in tumorigenicity, experiments in vitro and in vivo are needed. Siprashvili et al recently showed that wild-typeFHIT gene induced in human cell lines lack of endogenous Fhit protein expression reduced their tumorigencity in nude mice. But Otterson reported that the introduction of wild-type FHIT gene into HeLa cell did not change its tumorigencity. Therefore, the FHIT gene as a putative tumor suppressor still needs further study.Mucoepidermoid carcinoma cell line (MEC-1) was established by our department members. It has high tumori- gencity and metastasis. We found that the aberrant transcript of FHIT gene existed in MEC-1 cells. We transfected the cells with pRc CMV-FHIT vector to study the effect of FHIT gene over expression on cell proliferation, cell kinetics, and tumorigenicity and tumor metastasis in nude mice.1. The total RNA of Mucoepidermoid carcinoma MEC-1 cells, its derived cell lines M3, M3SP4, tongue squamous carcinoma cell line Teal 183, and its derived cell lines Tb, TbTl, and oral bottom squamous carcinoma