Expression patterns of murine beta-defensin-2 mRNA in Lewis lung carcinoma cells in vitro and in vivo.

AIM: To evaluate the anti-tumor activity of murine beta-defensin-2 (mBD-2) expression in vitro and in vivo. MATERIALS AND METHODS: Based on pcDNA3 vector, constructs containing mBD-2 cDNA coding mature defensin molecule (pcDNA3-mBD2), and Igk-mBD-2 insertion, coding secretory sequence plus mature defensin molecule (pcDNA3-Igk-mBD-2) were generated. Lewis lung carcinoma (3LL) cells were transfected in vitro with these plasmids and with blank pcDNA3 vector, and the proliferative rate and clonogenic ability of obtained cell lines cultivated in vitro were analyzed using (3)H-incorporation technique and colony formation in semi-soft medium, respectively. Expression of mBD-2 mRNA was studied by semiquantative RT-PCR analysis. Also, transfected cells were transplanted to C57B mice, and the patterns of tumor growth in vivo were analyzed by routine techniques. RESULTS: We have found out that in the 3LL cells transfected with pcDNA3-mBD-2 and pcDNA3-Igk-mBD-2, the expression of mBD-2 mRNA is significantly down regulated compared to wild-type cells and 3LL cells transfected with blank vector. The cells with suppressed mBD-2 expression differed from parental cells and cells transfected with blank vector by higher proliferation rate (p < 0.001) and higher clonogenic ability. The 3LL-mBD-2 and 3LL-Igk-mBD-2 cells that are transplanted to C57B mice gave rise to more aggressive tumors that possessed significantly higher growth rate (p < 0.01) than those that arise from wild-type 3LL cells. CONCLUSION: The obtained results indicate the relation between mBD-2 expession in 3LL cells and their proliferation rate and malignant phenotype, and also allow to hypothesize the possibility of regulation of mBD-2 mRNA expression in these cells by a feedback mechanism.