Anti-adult T-cell leukemia/lymphoma effects of indole-3-carbinol

• Main Authors: Okudaira Taeko, Sawada Shigeki, Ishikawa Chie, Machijima Yoshiaki, Uchihara Jun-nosuke, Tanaka Yuetsu, Taira Naoya, Mori Naoki
• Format: Article
• Language: English
• Published: BMC 2009-01-01
• Series: Retrovirology
• Online Access: http://www.retrovirology.com/content/6/1/7

<p>Abstract</p> <p>Background</p> <p>Adult T-cell leukemia/lymphoma (ATLL) is a malignancy derived from T cells infected with human T-cell leukemia virus type 1 (HTLV-1), and it is known to be resistant to standard anticancer therapies. Indole-3-carbinol (I3C), a naturally occurring component of <it>Brassica </it>vegetables such as cabbage, broccoli and Brussels sprout, is a promising chemopreventive agent as it is reported to possess antimutagenic, antitumorigenic and antiestrogenic properties in experimental studies. The aim of this study was to determine the potential anti-ATLL effects of I3C both <it>in vitro </it>and <it>in vivo</it>.</p> <p>Results</p> <p>In the <it>in vitro </it>study, I3C inhibited cell viability of HTLV-1-infected T-cell lines and ATLL cells in a dose-dependent manner. Importantly, I3C did not exert any inhibitory effect on uninfected T-cell lines and normal peripheral blood mononuclear cells. I3C prevented the G₁/S transition by reducing the expression of cyclin D1, cyclin D2, Cdk4 and Cdk6, and induced apoptosis by reducing the expression of XIAP, survivin and Bcl-2, and by upregulating the expression of Bak. The induced apoptosis was associated with activation of caspase-3, -8 and -9, and poly(ADP-ribose) polymerase cleavage. I3C also suppressed IκBα phosphorylation and JunD expression, resulting in inactivation of NF-κB and AP-1. Inoculation of HTLV-1-infected T cells in mice with severe combined immunodeficiency resulted in tumor growth. The latter was inhibited by treatment with I3C (50 mg/kg/day orally), but not the vehicle control.</p> <p>Conclusion</p> <p>Our preclinical data suggest that I3C could be potentially a useful chemotherapeutic agent for patients with ATLL.</p>