Ascorbic acid (vitamin C) improves the antineoplastic activity of doxorubicin, cisplatin, and paclitaxel in human breast carcinoma cells in vitro.

Cancer Lett 1996 Jun 5;103(2):183-9 (ISSN: 0304-3835)

Kurbacher CM; Wagner U; Kolster B; Andreotti PE; Krebs D; Bruckner HW
Department of Gynecology and Obstetrics, University of Bonn Medical Center, Germany.

Utilizing a microplate ATP bioluminescence assay, two human breast carcinoma cell lines, MCF- 7 and MDA-MB-231, were tested against doxorubicin ( DOX ), cisplatin (DDP), and paclitaxel (Tx) alone and in combination with ascorbic acid (Vit C ). In both cell lines, Vit C exhibited cytotoxic activity at high concentrations (i.e. 10(2)-10(3) microM). Both cell lines also were resistant to DOX . MCF- 7 was found to be DDP-resistant, MDA-MB-231 was moderately sensitive to DDP. Both cell lines were strongly sensitive to Tx. Vit C both at non-cytotoxic (1 microM) and moderately cytotoxic concentrations (10(2) microM) improved the cytotoxicity of DOX , DDP, and Tx significantly. Combination effects between Vit C and DDP or Tx were partly synergistic and partly additive or subadditive whereas a consistent synergism was found between Vit C and DOX . The mechanisms by which Vit C potentiates the cytostatics studied are yet unclear and should be evaluated further.