ヨゴサワ　シンゴ   YOGOSAWA Shingo   与五沢　真吾    所属   埼玉医科大学  保健医療学部 臨床検査学科    職種   准教授
論文種別	学術雑誌(原著)
言語種別	英語
査読の有無	査読あり
表題	A combination of indol-3-carbinol and genistein synergistically induces apoptosis in human colon cancer HT-29 cells by inhibiting Akt phosphorylation and progression of autophagy
掲載誌名	正式名：MOLECULAR CANCER ISSNコード：1476-4598
出版社	BIOMED CENTRAL LTD
巻・号・頁	8,100頁
著者・共著者	Yoshitaka Nakamura,Shingo Yogosawa,Yasuyuki Izutani,Hirotsuna Watanabe,Eigo Otsuji,Tosiyuki Sakai
発行年月	2009/11
概要	Background: The chemopreventive effects of dietary phytochemicals on malignant tumors have been studied extensively because of a relative lack of toxicity. To achieve desirable effects, however, treatment with a single agent mostly requires high doses. Therefore, studies on effective combinations of phytochemicals at relatively low concentrations might contribute to chemopreventive strategies. Results: Here we found for the first time that co-treatment with I3C and genistein, derived from cruciferous vegetables and soy, respectively, synergistically suppressed the viability of human colon cancer HT-29 cells at concentrations at which each agent alone was ineffective. The suppression of cell viability was due to the induction of a caspase-dependent apoptosis. Moreover, the combination effectively inhibited phosphorylation of Akt followed by dephosphorylation of caspase-9 or down-regulation of XIAP and survivin, which contribute to the induction of apoptosis. In addition, the co-treatment also enhanced the induction of autophagy mediated by the dephosphorylation of mTOR, one of the downstream targets of Akt, whereas the maturation of autophagosomes was inhibited. These results give rise to the possibility that co-treatment with I3C and genistein induces apoptosis through the simultaneous inhibition of Akt activity and progression of the autophagic process. This possibility was examined using inhibitors of Akt combined with inhibitors of autophagy. The combination effectively induced apoptosis, whereas the Akt inhibitor alone did not. Conclusion: Although in vivo study is further required to evaluate physiological efficacies and toxicity of the combination treatment, our findings might provide a new insight into the development of novel combination therapies/chemoprevention against malignant tumors using dietary phytochemicals.
DOI	10.1186/1476-4598-8-100
PMID	19909554