Inhibition of prostate cancer RM1 cell growth in vitro by hydroxyapatite nanoparticle-delivered short hairpin RNAs against Stat3

Abstract

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 plasmid-based Stat3 specific short hairpin RNA (sh-Stat3) delivered by hydroxyapatite nanoparticles (HAP). HAP carrying sh-Stat3 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 transcription-quantitative polymerase chain reaction and Stat3, Cyclin D1, B cell lymphoma 2 apoptosis regulator (Bcl-2), vascular endothelial growth factor (VEGF), Bcl-2 associated X apoptosis regulator (Bax) and cleaved-caspase-3 protein expression levels were detected using western blot analysis. The results demonstrated that HAP-delivered sh-Stat3 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. Bcl-2, VEGF and Cyclin D1 were also significantly downregulated, but cleaved-caspase-3 and Bax mRNA and protein expression levels were significantly upregulated. HAP-delivered sh-Stat3 decreased RM1 cell viability in vitro, and HAP assisted plasmid-based delivery of shRNA into tumor cells. The present results suggest that HAP may be a useful method for successful shRNA delivery into tumors.