Potentiation of antitumor activity of mitomycin C by estradiol: Studies of human breast carcinoma xenografts serially transplanted into nude mice

✍ Scribed by Oka, Shoichi; Kubota, Tetsuro; Takeuchi, Tooru; Kitajima, Masaki

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 579 KB
• Volume: 61
• Category: Article
• ISSN: 0022-4790
• DOI: 10.1002/(sici)1096-9098(199604)61:4<256::aid-jso4>3.0.co;2-9

✦ Synopsis

The effect of experimental cancer chemotherapy with mitomycin C (MMC) was studied using three estrogen-receptor (ER)-positive (MCF-7, R-27, and Br-10) and one ER-negative (MX-1) human breast carcinoma xenograft serially transplanted into nude mice, and the effect of estradiol (E2) priming on the antitumor activity of MMC was investigated. Intramuscular injection of E2 at 1 mgkg changed the ER state and increased the growth fraction detected by flow cytometry, although the growth rate of ERpositive tumors was not effective by E2 priming. MMC suppressed the growth of the four xenografts in a dose-dependent manner. When 1 mgkg E2 was administered 1 h before MMC treatment, which was given intraperitoneally at a dose of 3 mgkg, the antitumor activity of MMC was increased in comparison with MMC alone in ER-positive strains, although the effect of MMC on MX-1 was not changed by E2-priming. Priming with E2 at ths dose increases the growth fractions of ER-positive breast carcinoma cells, which are sensitive to MMC, resulting in increased antitumor activity of MMC. This E2-primed MMC chemotherapy may be of value in the treatment of ER-positive human breast cancer.