Vitamins C and K3 Sensitize Human Urothelial Tumors to Gemcitabine

Purpose

We evaluated the antitumor effects of vitamins C and K3 for human urothelial carcinoma and the potential use of the combination of vitamins C plus K3 as a sensitizing agent for conventional chemotherapy for urothelial carcinoma.

Materials and Methods

The antiproliferative and apoptotic effects of vitamin C alone, vitamin K3 alone, vitamins C plus K3, gemcitabine alone and gemcitabine plus vitamins C plus K3 were assessed in vitro by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, propidium iodide staining and flow cytometry. For in vivo studies we implanted UMUC-14 tumorigenic urothelial carcinoma cells into the subcutis of nude mice. One week later we treated 10 mice each with saline (control), vitamins C plus K3, gemcitabine or gemcitabine plus vitamins C plus K3. Treatment was continued for 4 weeks, followed by necropsy. Tumor volume was measured and tumor kinetics were established. Apoptosis and proliferation were evaluated in tumor sections using immunohistochemistry and TUNEL assay.

Results

Vitamins C plus K3 induced cytostasis and caused apoptosis to a greater degree than either vitamin alone (p <0.05). Vitamins C plus K3 also substantially augmented the effects of gemcitabine in vitro. There were 32.3% apoptosis with gemcitabine plus vitamins C plus K3, 5.3% with gemcitabine alone and 15.8% with vitamins C plus K3 alone (p <0.05). In vivo tumor growth was substantially inhibited by gemcitabine plus vitamins C plus K3 compared with that in the control or for either agent alone. Mean tumor weight and growth rate in the gemcitabine plus vitamins C plus K3 group (237 mg and 11.3 mm³ daily) were decreased compared with those in the control (530 mg and 34.3 mm³ daily), and those for vitamins C plus K3 alone (490 mg and 25.2 mm³ daily) and gemcitabine alone (400 mg and 21.3 mm³ daily) (p <0.05).

Conclusions

Vitamins C and K3 have significant antiproliferative and apoptotic effects when used in combination. This combination enhances the efficacy of gemcitabine against bladder cancer in vivo.

Key Words:  bladder , bladder neoplasms , urothelium , ascorbic acid , vitamin K3

Abbreviations and Acronyms:  CK3, combination of vitamins C and K3 , Gem, gemcitabine , IHC, immunohistochemical analysis , MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide , PBS, phosphate buffered saline , PCNA, proliferating cell nuclear antigen , UC, urothelial carcinoma