ABSTRACT
Objective: To investigate the chemo-sensitivity enhancing effect and its major active mechanism of Shengmai Injection (SMI). Methods: MTT assay was used to determine the chemo-sensitivity enhancing activity of SMI combined with various current- used chemotherapeutic drugs. Flow cytometry was conducted to determine the effect of Epirubicin combined with SMI on the cell cycle distribution and apoptotic cell death, and the mRNA expression level of MDR-1 gene was determined by RT-PCR. Results: SMI (30 μL/mL) combined with gemcitabine, cisplatin, paclitaxel, and Epirubicin exihibited the potent antiproliferative effects on human lung carcinoma A549, gastric carcinoma SGC-7901, breast carcinoma MCF-7, and hepatocellular carcinoma HepG-2 cell lines, respectively. SMI showed the most significant enhancing effects on HepG-2 cells in combination with Epirubicin, and the sensitivity of HepG-2 to Epirubicin was increased by 16 fold. Whereas SMI (30 μL/mL) alone did not affect the cell cycle distribution and apoptosis of HepG-2 cells, it enhanced the cellular responses when combined with Epirubincin together with a down-regulated mRNA level of MDR-1 gene. Conclusion: SMI combined with the different chemotherapeutic drugs could enhance the sensitivity of cancer cells significantly via down-regulating the mRNA expression level of MDR-1 and the expression of P-glucoprotein with the excretion of drugs.