A Experimental Study Of SPATA12 Genes As A Tumor Suppressor

Loss of heterozygosis is the earliest change of genetics for tumor-suppressor genes inactivation,which play a key role in tumorigenesis.The relationship between LOH and tumor-suppressor genes has been applied to look for candidate tumor-suppressor genes.SPATA12 is a novel gene associated with spermatogenesis,and located on the chromosome 3p14 which is an important region of LOH,suggesting that it may be associated with tumorigenesis. Previous research has indicated that the number of tumor cells was increased in G0-G1 phrase and decreased in S and M phrases in Hela cell after SPATA12 transfected. It means that the expression of SPATA12 could inhibite tumor cell proliferation through cell cycle arrest in G0/G1 phrase. Based on the previous work,our hypothesis is SPATA12 may have some characteristics of tumor suppressor gene. In this research,a series of celluar and molecular biology methods such as in situ hybridization,MTT,clone formation assay,cell scratch test and RT-PCR were used to understand the relationship between SPATA12 gene and tumorigenesis.First,the deletion rate of SPATA12 gene in testicular cancers and other multi-organ tumors were detected with tissue microarray by using in situ hybridization. The results are as follow:(1) Loss of SPATA12 were found in all different types of testicular cancer,suggesting that SPATA12 gene might be a candidate inhibitor associated with male germ cell tumors. (2)There are no expression of SPATA12 in ovary tumors,breast tumors,liver tumors and brain tumors,showing the association between loss of SPATA12 and the development of tumors. However,positive signals could be observed in part of stomach cancer,pancreatic cancer,colon cancer,and thyroid cancer.We speculated that the mutation of SPATA12 gene might contribute to the change of expression level in these tumors. (3)SPATA12 has no expression in malignant small cell carcinomas and the deletion in part of non-small cell carcinomas. In different pathologic types of non-small cell carcinomas,the highest deletion rate of SPATA12 expression was observed in adenocareinoma,and then followed by squalors cell carcinoma, characinoid tumor and large cell carcinoma,indicating deletion of SPATA12 gene is associated with different pathological types of lung tumors.Then,MTT assay,colony formation and cell plate scratch experiments were used to examine the effects of SPATA12 gene on Hela cells.We found that exogenous SPATA12 gene could significantly inhibit proliferation,colony formation and migration of tumor cells.Finally,the relationship of SPATA12 gene and cell cycle related genes were studied by RT-PCR. It was shown that the expression of cyclinA1 gene was suppressed obviously,and the level of cyclinD1 was reduced as well. However,no obvious changes were observed in mRNA ecpression of cyclinB1 and cyclinE1.In summary,SPATA12 gene might be an inhibitor during the development of cancer such as male germ cell tumor via relating the cell cycle genes.