Abstract 2822: Ascorbic acid synergistically potentiates antimetastatic effect of natural products on 4T1 tumors.
Authors: Cha John , Roomi M. Waheed , Rath Matthias , Niedzwiecki Aleksandra 
Published: August 2014

Our main objective was to determine the differential response of female gulonolactone oxidase (Gulo) mice challenged with 4T1 to vitamin C deficient, subclinical vitamin C sufficient, or vitamin C combined with other additional natural products (EQC) diets against 4T1 secondary growth phase metastasis to lungs, kidneys, and liver. Live murine 4T1 cells (5x105) were administered subcutaneously to the right flank of female Gulo (-/-) mice (n=27) 35-40 weeks of age and 18 age matched female wild-type mice. Tumors were established for an additional 2 weeks on subclinical vitamin C (100mg/L in water) in the Gulo (-/-) group, or with regular food and water in the wild-type vitamin C-generating mice. Tumor measurements were taken and the Gulo (-/-) mice were distributed into 3 groups (n=9 in each) to ensure average tumor burden was equivalent before therapy. Mice were then maintained for an additional 2 weeks on either subclinical vitamin C in water, subclinical C water + vitamin C (equivalent to that provided by 0.5% EQC supplemented diet), and subclinical C water + 0.5% EQC supplemented diet. Wild-type mice received an additional 2 weeks of either regular murine diet or 0.5% EQC supplemented food and regular water. At the endpoint, serum was collected, lungs, livers, and kidneys were evaluated for metastatic burden, and tissues collected for histology. Tumors were also harvested, weighed, and sectioned for histology. EQC exhibited the strongest anti-metastatic effect upon the second growth phase in scorbutic Gulo (-/-) mice as well as wild type vitamin C generating mice. Gulo (-/-) mice maintained throughout the study on subclinical vitamin C presented with the worst outcomes, including novel renal involvement. Vitamin C in diet equivalent to that in 0.5% EQC afforded only protection against novel renal pathology, but the metastatic burden was similar to that in subclinical C group. 0.5% EQC abrogated the cases of moderate to severe metastasis in scorbutic Gulo (-/-) mice by 16% compared to subclinical vitamin C group. In wild-type mice, 0.5% EQC abrogated the cases of moderate to severe metastasis by 37%. This study demonstrates that 0.5% EQC is superior to vitamin C alone in reducing metastasis from a primary 4T1 tumor and that prior scurvy is deleterious upon host resistance to primary tumors and reduces the efficacy of subsequent therapy against metastasis. Prior endogenous vitamin C generation in wild-type mice before tumor inoculation and continuous vitamin C generation during therapy with 0.5% EQC suggests that vitamin C both enhances host resistance and synergistically potentiates the effect of additional therapy. Tumor mass itself was not related to metastatic burden, suggesting that differing biochemical composition of the stromal and tumor structures are responsible for a metastatic or non-metastatic tumor of equal size.

Citation Format: John Cha, M. Waheed Roomi, Matthias Rath, Aleksandra Niedzwiecki. Ascorbic acid synergistically potentiates antimetastatic effect of natural products on 4T1 tumors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2822. doi:10.1158/1538-7445.AM2013-2822