Polar solvents in the chemoprevention of dimethylbenzanthracene-induced rat mammary cancer
Arch Surg 1986 Dec;121(12):1455-9
Differentiating agents have been used experimentally and clinically as an adjuvant in the treatment of cancer, but their role in chemoprevention is limited. We used 5% dimethylsulfoxide (DMSO), 1% and 4% methylsulfonylmethane (MSM), 0.3% N-methylformamide (NMF), and retinol acetate (RA) in the chemoprevention of rat mammary breast cancer. One hundred fifty 42-day-old Sprague-Dawley rats were randomized into six groups (control, RA, DMSO, 1% MSM, NMF, and 4% MSM) and received chemopreventive agents along with standard rat chow ad libitum. Eight days later, 15 mg of 7,12-dimethylbenzanthracene was given by oral gastric intubation. The animals were examined weekly for tumor incidence and size (biplanar analysis). Animals were followed up for 240 to 300 days. Tumor incidence was not statistically affected. Time to appearance (latency period) of both tumors and cancers were prolonged by NMF, DMSO, and 4% MSM. Doubling times of all cancers produced were prolonged by DMSO and RA. No group exhibited toxic reactions or significant weight loss. Polar solvents and differentiating agents, specifically NMF, DMSO, and 4% MSM, were effective in the chemoprevention of dimethylbenzanthracene-induced mammary cancers.
Polar solvents and colon cancer Use of polar solvents in chemoprevention of 1,2-dimethylhydrazine-induced colon cancer
Cancer 1988 Sep 1;62(5):944-8
To examine the effect of the polar solvents on 1,2-dimethylhydrazine (DMH)-induced colon cancer, 100 male Sprague-Dawley rats were randomly allocated to a control and three treatment groups. Treated animals received N-methylformamide (NMF), dimethylsulfoxide (DMSO), or methylsulfonylmethane (MSM) added to drinking water 1 week before carcinogen injections commenced and for the duration of the experiment. Primary tumors were detected by serial laparotomy under ether anesthesia performed at 2-month intervals and commencing after carcinogen injections had been completed. The average time to tumor onset was significantly delayed in rats receiving NMF and MSM (P = 0.0141 and 0.0398 respectively, Mantel-Haenszel test). In addition, fewer poorly differentiated tumors were noted in treatment groups. No weight loss or toxicity was observed. These findings demonstrate that the polar solvents significantly reduce the latent period to tumor onset in DMH-induced colon cancer and indicate the need to further investigate such compounds as chemopreventive agents.