Inhibition of prostate cancer RM1 cell growth in vitro by hydroxyapatite nanoparticle­delivered short hairpin RNAs against Stat3.

The present study investigated the effect of signal transducer and activator of transcription 3 (Stat3) interference on RM1 prostate cancer cell viability in vitro, using plasmid­based Stat3 specific short hairpin RNA (sh­Stat3) delivered by hydroxyapatite nanoparticles (HAP). HAP carrying sh­Stat3 plasmids were transfected into tumor cells. MTT assays were used to measure RM1 cell viability 24 and 48 h following transfection, and the apoptosis rate and cell cycle phase distribution were determined by flow cytometry. Stat3 mRNA expression levels were measured by reverse transcription­quantitative polymerase chain reaction and Stat3, Cyclin D1, B cell lymphoma 2 apoptosis regulator (Bcl­2), vascular endothelial growth factor (VEGF), Bcl­2 associated X apoptosis regulator (Bax) and cleaved­caspase­3 protein expression levels were detected using western blot analysis. The results demonstrated that HAP­delivered sh­Stat3 significantly decreased RM1 cell viability through the promotion of cell cycle arrest and apoptosis. Stat3 mRNA and protein expression levels were significantly downregulated in RM1 cells. Bcl­2, VEGF and Cyclin D1 were also significantly downregulated, but cleaved­caspase­3 and Bax mRNA and protein expression levels were significantly upregulated. HAP­delivered sh­Stat3 decreased RM1 cell viability in vitro, and HAP assisted plasmid­based delivery of shRNA into tumor cells. The present results suggest that HAP may be a useful method for successful shRNA delivery into tumors.