Effectiveness of small interfering RNA (siRNA) against the Mcl-1 gene in a canine mammary gland tumor cell line

The effect of down-regulation of Mcl-1 expression by small interfering RNA (siRNA) against the canine Mcl-1 gene on apoptosis was investigated by transfecting CF33 (canine mammary gland tumor cell line) with siRNA using cationic liposomes. The siRNA against canine Mcl-1 increased the rate of apoptotic cells and decreased the numbers of viable cells. Further, sequence-specific down-regulation of Mcl-1 expression was measured by real time-PCR and Western blot analysis. The siRNA directed against the Mcl-1 gene reduced both the mRNA and protein expression in the CF33. Our study suggests the importance of Mcl-1 in canine mammary tumors for inducing apoptosis and reinforces using Mcl-1 as a putative therapeutic target in canine mammary gland tumor.