Cytotoxic Activity of Cobalamin in Cultured Malignant and Nonmalignant Cells

Abstract

The cytotoxic effect of cobalamin (vitamin B₁₂) on the growth of malignant and nonmalignant cell lines in culture has been examined. Among the four cobalamins studied, 5’-deoxyadenosylcobalamin, an enzymatically active derivative, was an effective cytotoxic agent. The data indicated that adenosylcobalamin seemed to act selectively on fast-growing malignant cells. Methylcobalamin was also effective at elevated concentrations. Cyanocobalamin was not toxic to all cell lines studied. Hydroxocobalamin at very high concentrations was able to slightly decrease growth of certain cell lines. The results support the hypothesis that the cytotoxic effect of cobalamin was associated with the metabolic activities of this vitamin at the cellular level. Also, cobalamin may be a potential antitumor agent.

Influence of Cobalamin on the Survival of Mice Bearing Ascites Tumor

“…However, cyanocobalamin has practically no effect on tumor growth. These observations were in good agreement with results in previous experiments in which in vitro cell cul ture technique was used [24]. The ratios of median sur vival time of a test group to median survival time of con trol for these mice are shown in parentheses in table 1.…”

“…21], In addition, a deficiency of vitamin B|2 decreased the potency of certain carcinogens in rats [22,23], A recent in vitro study with cultured cells indicated that cobalamins were able to inhibit the growth of several malignant cell lines [24], In these experiments, the meta-bolically active forms, methylcobalamin and 5'-deoxyadenosylcobalamin. were found to be effective but the metabolically inactive cyanocobalamin bad practically no ef fect [24]. In the present study, in vivo experiments were carried out to examine the effects of three different forms of cobalamin on the survival of mice bearing ascites tumors.…”

Nutrition and cancer: A review of the evidence for an anti-cancer diet

“…Methylcobalamin, but not cyanocobalamin, increased the survival time of mice bearing implanted leukemia tumor cells [113]. 5'-deoxyadenosylcobalamin and methylcobalamin, but not cyanocobalamin, were shown to be effective cytotoxic agents [114]. Methylcobalamin also was able to increase survival time and reduce tumor growth in laboratory mice [115].…”

Methylcobalamin Decreases mRNA Levels of Androgen-Induced Growth Factor in Androgen-Dependent Shionogi Carcinoma 115 Cells

“…Several previous studies have described associations between cobalamins and cancer. Other studies showed that cobalamins were selectively cytotoxic to fastgrowing malignant cells in culture (7) and were able to increase significantly the survival time of tumor-bearing mice (8). A second study showed that the atypical bronchial squamous metaplasia, frequently present in the lungs of smokers before the development of lung cancer, was improved by supplementation with folate and vitamin B-12 (6).…”