Beneficial effects of a vanadium complex with cysteine, administered at low doses on benzo (alpha)pyrene-induced leiomyosarcomas in Wistar rats

Background: Vanadium is a potent environmental and body metal, possessing r emarkable antitumor and antidiabetic properties. Vanadium salts and complex es have been widely investigated for their anticarcinogenic properties in e xperimental carcinogenesis. In the present study the antitumor effects of a new vanadium complex with cysteine in relation to identical doses of vanad yl sulfate and cysteine, in tumor bearing rats are investigated. Materials and Methods: male wistar rats were injected with benzo(a)pyrene and divided into four groups of 21 rats each. Control group was treated only with BaP. The first group(TR-I) was treated by vanadyl sulfate per os at daily doses of 0.5 mg of V/kg b. w per day. The second (TR-2) by cysteine at doses of 4.5 mg/ kg b.w per day and the third group (TR-3), by the complex V(III)-cy steine at daily doses of V 0.5 mg/kg b.w (containing cysteine at concentrat ions of 4.5 mg/b.w). Treatment was started when tumors were developed( evid enced from a palbable mass at the site of Bap injection) and went on till d eath. Toxicological tests were performed in 27 rats divided into a control group and two test groups; T-I administered with vanadyl sulfate at daily d oses of 18.5 mg V/kg b.w and T-L? group with V(III)-cysteine complex at dai ly doses of 18.5 V/kg b.w, for 9 weeks. Mean survival time death rate, tumo r growth rate, the carcinogenic potency of BaP, and the anticarcinogenic po tency in relation to histological findings in each treatment group were cal culated in each group in order to evaluate the antitumor effects of the sub stances used. Results: Vanadyl sulfate, cysteine and V(III)-cysteine exerte d antitumor effects on leiomyosarcoma bearing Wistar rats. However, V(III)- complex exerted much more potent effects than the other treatments, signifi cantly prolonging mean survival time, retarding tumor growth rate and decre asing the carcinogenic potency of BaP in the TR-3 group, in comparison to t he control and the TR-1 and TR-2 groups. Moreover V(III)-cysteine complex r esulted in complete remission of 4 (19.7%) of the tumor bearing rats. Blood , urine, biochemical routine rests as well as autopsy did not reveal any to xic effects either of vanadyl sulafate or V(lll)-cysteine complex. Conclusi ons:Vanadyl sulfate, cysteine and V(III)-cysteine complex exerted antitumor effects in tumor bearing rats. The V(III)-cysteine complex, however, exert s much move potent effects,as evident from the results of the present study . These beneficial effects of the above complex, in combination with its lo w toxicity provide evidence suggest its possible application in the treatme nt of human malignant diseases.