Suppression of clusterin expression enhanced cisplatin-induced cytotoxicity on renal cell carcinoma cells

To evaluate whether antisense transfection targeted against clusterin enhances the chemosensitivity in renal cell carcinoma.

Caki-1, a renal cell carcinoma cell line, and cisplatin were used as chemotherapeutic agents. Clusterin expression of Caki-1 cells after treatment with cisplatin was measured by Western blot analysis. After the construction of a clusterin suppression vector, clusterin expression was compared between Caki-1 cells transfected with the clusterin suppression vector (Caki-1/AS), Caki-1 cells transfected with control vector (Caki-1/VO), and parental Caki-1 cells. Tumor cell viability was measured with the MTT assay at 24 and 48 hours after cisplatin treatment.

The expression of clusterin increased gradually in Caki-1 cells, peaking at 24 hours, and was reduced to an almost undetectable level at 48 hours after cisplatin treatment. Clusterin expression was suppressed, and the percentage of viable tumor cells decreased significantly more in the Caki-1/AS than in the Caki-1/VO or parental Caki-1 cells at 24 hours after cisplatin treatment. The change in chemosensitivity of the Caki-1/AS cells lost its significance at 48 hours after cisplatin treatment.

Our results showed that clusterin expression increased transiently after treatment of cisplatin, and its suppression by antisense transfection enhanced the cisplatin-induced cytotoxicity of renal cell carcinoma cells. Clusterin suppression may be a useful modality in enhancing the effects of cytotoxic chemotherapy in renal cell carcinoma.