9, 10-dimethyl-1, 2-benzanthracene에 의해유발된 햄스터 구강암에 대한 polyadenylic-polyuridylic acid의 억제효과

Abstract

More than 90% of all malignant tumors of the oral cavity are squamous cell carcinomas. Intraoral squamous cell carcinomas may develop from preexisting premalignant lesion such as leukoplakia or erythroplakia. Because the premalignant lesion of the oral cavity can be easily detected clinically, oral leukoplakia is recently investigated as one of the main topics for cancer prevention. It has already been known that the malignant disease is correlated with the immune state of the host and certain immunologic mechanisms are thought to be involved in the transformation to the squamous cell carcinoma from the premalignant lesion. In an attempt to evaluate the effect of increased host immunity on the tumor occurrence, polyadenylic-polyuridylic acid(Poly(A), Poly(U)) was injected intraperitoneally to the syrian golden hamster with application of 9, 10-dimethyl-1, 2-benzanthracene(DMBA) in the buccal pouch. Tumor multiplicity, histologic findings and NK cell cytotoxicity were evaluated. The results are as follows: 1. Tumor multiplicity was decreased in the group I & II with Poly(A), Poly (U) treatment when compared to that in the group Iii without treatment. In particular, the group I with Poly(A), Poly(U) treatment 1 week before DMBA application showed dramatically reduced tumor multiplicity. 2. The group II with Poly(A), Poly(U) treatment 2 weeks after DMBA application also showed decreased tumor multiplicity when compared to the group III without treatment but DMBA application only. 3. The invasive growth of carcinoma was reduced in the group I, II with Poly(A), Poly(U) treatment when compared to the group III. 4. NK cell cytotoxicity was incresed increased in the group V with DMBA application only when compared to that of group IV, however, no statistical significance was found in the difference of the NK cell cytotoxicity among the groups. According to the above results, it is concluded that Poly(A), Poly(U) has showed inhibitory effect on DMBA induced oral cancer in hamster buccal pouch and the inhibitory effect is most prominent when Poly(A), Poly(U) was treated before DMBA application. But the further studies about the roles of the Poly(A), Poly(U) on the T cell activity and cytokine secretion as well as on the NK cell activity should be followed.