ABSTRACT
This study is to investigate the effect of small interfering RNA targeting STAT3 (STAT3-siRNA) enhancing antitumor activity of doxorubicin. RT-PCR and Western blotting were used to test the expression of STAT3 mRNA and protein in the HepG2, HeLa and K562/DOX cells and the effect of STAT3-siRNA on the expression of STAT3 mRNA and protein. MTT and Trypan blue assay were performed to determine the inhibitory effect of STAT3-siRNA on HepG2, HeLa and K562/DOX cells and the effect of STAT3-siRNA enhancing antitumor activity of doxorubicin. The effects of STAT3-siRNA on intracellular accumulation of doxorubicin and cell apoptosis were performed by Arrary Scan V(TI)HCS600 High-Contents. The results showed that STAT3 gene, STAT3 and pSTAT3 protein were highly expressed in HepG2, HeLa and K562/DOX cells and STAT3-siRNA decreased the expression of STAT3 mRNA and protein. STAT3-siRNA inhibited the growth of HepG2, HeLa and K562/DOX cells. STAT3-siRNA in combination with doxorubicin decreased by 3.13, 5.22 and 1.74 fold of IC50 of HepG2, HeLa and K562/DOX cells compared with doxorubicin only. Intracellular accumulation of doxorubicin increased by 16.8%, 12.87% and 25.67% respectively in HepG2, HeLa and K562/DOX cells in the presence of STAT3-siRNA. An enhancement of doxorubicin-induced cell apoptosis was observed in HepG2, HeLa and K562/DOX cells treated with STAT3-siRNA. The results suggested that STAT3-siRNA could enhance the antitumor activity of doxorubicin on HepG2, HeLa and K562/DOX cells.
Subject(s)
Humans , Antibiotics, Antineoplastic , Metabolism , Pharmacology , Apoptosis , Cell Proliferation , Doxorubicin , Metabolism , Pharmacology , Drug Synergism , HeLa Cells , Hep G2 Cells , K562 Cells , RNA, Messenger , Genetics , RNA, Small Interfering , Genetics , STAT3 Transcription Factor , Genetics , Metabolism , TransfectionABSTRACT
This study is to investigate the inhibitory effect and mechanism of prosapogenin A (PSA) on MCF7. MTT assay was performed to determine the inhibitory effect of PSA on MCF7 cells. PI/Hoechst 33342 double staining was used to detect cell apoptosis. RT-PCR was used to test the mRNA levels of STAT3, GLUT1, HK and PFKL. Western blotting was performed to determine the expression of STAT3 and pSTAT3 protein in MCF7 cells. The results showed that PSA could dose-dependently inhibit cell growth of MCF7 followed by IC50 of 9.65 micrmol x L(-1) and promote cell apoptosis of MCF7. Reduced mRNA levels of STAT3, HK and PFKL were observed in MCF7 cells treated with 5 micromol x L(-1) of PSA. PSA also decreased the level of pSTAT3 protein. STAT3 siRNA caused decrease of mRNA of GLUT1, HK and PFKL which indicated STAT3 could regulate the expressions of GLUT1, HK and PFKL. The results suggested that PSA could inhibit cell growth and promote cell apoptosis of MCF7 via inhibition of STAT3 and glycometabolism-related gene.