Oxymatrine synergistically enhances antitumor activity of oxaliplatin in colon carcinoma through PI3K/AKT/mTOR pathway

• Published in: Apoptosis (London) Vol. 21; no. 12; pp. 1398 - 1407
• Main Authors: Liu, Yan, Bi, Tingting, Wang, Zheng, Wu, Guoliang, Qian, Liqiang, Gao, Quangen, Shen, Genhai
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-12-2016; Springer Nature B.V
• Subjects: Alkaloids - administration & dosage; Animals; Antineoplastic Agents - administration & dosage; Apoptosis - drug effects; Biochemistry; Biomedical and Life Sciences; Biomedicine; Cancer Research; Cell Biology; Colonic Neoplasms - drug therapy; Colonic Neoplasms - genetics; Colonic Neoplasms - metabolism; Cytotoxicity; Drug Synergism; Drugs, Chinese Herbal - administration & dosage; Humans; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Oncology; Organoplatinum Compounds - administration & dosage; Phosphatidylinositol 3-Kinases - genetics; Phosphatidylinositol 3-Kinases - metabolism; Proto-Oncogene Proteins c-akt - genetics; Proto-Oncogene Proteins c-akt - metabolism; Quinolizines - administration & dosage; Sophora; Synergistic effect; TOR Serine-Threonine Kinases - genetics; TOR Serine-Threonine Kinases - metabolism; Virology; Xenograft Model Antitumor Assays; Synergistically; Oxaliplatin; Colon carcinoma; Oxymatrine; PI3K/AKT
• ISSN: 1360-8185; 1573-675X
• DOI: 10.1007/s10495-016-1297-3

Oxymatrine (OMT), one of the main active components of extracts from the dry roots of Sophora flavescens, has been reported to possess many pharmacological properties including cancer-preventive and anti-cancer effects. The aim of the present study is to explore the efficiency of combination therapy with OMT and oxaliplatin (OXA) and identify the in vitro and in vivo cytotoxicity on colon cancer lines (HT29 and SW480) and mice model. Cells were treated with OMT and/or OXA and subjected to cell viability, colony formation, apoptosis, cell cycle, western blotting, xenograft tumorigenicity assay and immunohistochemistry. The results demonstrated that OMT and OXA inhibited the proliferation of colon cancer cells, and combination therapy of OMT and OXA resulted in a combination index < 1, indicating a synergistic effect. Co-treatment with OMT and OXA caused G0/G1 phase arrest by upregulating P21, P27 and downregulating cyclin D, and induced apoptosis through decreasing the expression of p-PI3K, p-AKT, p-mTOR, p-p70S6K. In addition, pretreatment with a specific PI3K/AKT activator (IGF-1) significantly neutralized the pro-apoptotic activity of OXA + OMT, demonstrating the important role of PI3K/AKT in this process. Moreover, in nude mice model, co-treatment displayed more efficient inhibition of tumor weight and volume on SW480 xenograft mouse model than single-agent treatment with OXA or OMT. Immunohistochemistry analysis suggests the combinations greatly suppressed tumor proliferation, which consistent with our in vitro results. In conclusion, our findings highlight that the combination therapy with OMT and OXA exerted synergistic antitumor effects in colon cancer cells through PI3K/AKT/mTOR pathway and combination treatment with OMT and OXA would be a promising therapeutic strategy for colon carcinoma treatment.