Expression of Bcl-2 Gene in Human Renal Cell Carcinoma Associated with Drug Resistance and Metastatic Potential / 대한비뇨기과학회지

ABSTRACT

PURPOSE: To investigate whether the up-regulation of Bcl-2 gene expression may be associated with chemotherapy resistance and malignant progression in human renal cell carcinomas (HRCC). MATERIALS AND METHODS: The HRCC cell line, SN12C, was cultured in MEM medium, supplemented with 10% FBS. Full length of Bcl-2 cDNA was obtained using the sense primer (5'-ATGGCGCACGCTGGGAGAACGG-3') and the antisense primer (5'-TCACTTGTGGCTCAGATAGG-3') and inserted into SN12C cells to establish stable cells expressing the Bcl-2 gene (SN12C/smcb2). To investigate the response to doxorubicin in orthotropic organs, SN12C/smcb2 and parental cells were implanted into the subcapsular renal tissue of nude mice (n=5). The mice were treated with doxorubicin (8mg/kg) on days 8 and 15 following tumor cell implantation. Tumor tissues, obtained from the kidneys and lungs, were ex vivo cultured (SN12C/smcb2-kidney and SN12C/smcb2-lung, respectively). To compare the metastatic potential in these cell lines, the gelatinolytic activity was measured by zymogram and the expression of type IV collagenase (MMP-9) examined by western blot. RESULTS: In the in vitro study, the SN12C/smcb2 was more resistant to doxorubicin than the parental cells, and treatment and those cells produced a higher rate of tumor formation and metastasis. The SN12C/ smcb2-kidney showed higher gelatinolytic activity than the parental cells. Higher expression levels of type IV collagenase were detected in the SN12C/smcb2-lung and SN12C/smcb2-kidney, but barely detected in SN12C. CONCLUSIONS: The up-regulation of Bcl-2 gene expression in HRCC cells induces drug resistance to doxorubicin and increases the metastatic potential. Although the drug resistance induced by Bcl-2 over-expression enhances distant metastasis (lung), the up-regulation of Bcl-2 may enhance the malignant potential of tumor cells and produce distant metastasis.