PURPOSE: Ascorbic acid (AA), the natural antioxidant, has been demonstrated to exert an antimetastatic action; however, AA is quite unstable in physiological condition. The aim of the present study is to investigate the stability, the antioxidation and the antimetastatic effects of three lipophilic AA derivatives in vitro as well as in vivo. METHODS: The 95D cells were treated with ascorbic acid-2-O-phosphate-6-O-laureate (AA2P6L), ascorbic acid-2-O-phosphate-6-O-myristate (AA2P6M) and ascorbic acid-2-O-phosphate-6-O-stearate (AA2P6S). AA derivatives' stability in medium under cell culture condition, in the presence and in the absence of 95D cells, was assessed by high-performance liquid chromatography assay. Cell viability and intracellular oxidative stress were measured by MTT assay and CDCFH assay, respectively. Wound healing assay and cell adhesion assay were used to investigate the antimetastatic activities against 95D cells in vitro, and the C57BL/6 mice model was used to evaluate the antimetastatic action in vivo. RESULTS: All the three AA derivatives exhibited excellent stability, significantly different from AA. Results of MTT assay showed that IC(50) values of the cytotoxicity of those AA derivatives, namely AA2P6L, AA2P6M and AA2P6S, were 38.46, 28 and 22.97 microg/ml, while the CDCFH assay indicated that EC(50) values of antioxidant effects on 95D cells were 31.12, 33.51 and 38.31 microg/ml, respectively. Through the ratio of IC(50) vs EC(50) for AA derivatives, AA2P6L was demonstrated to be the most effective AA derivative, which retained the antioxidant ability as well as low cytotoxicity. AA2P6L dose-dependently inhibited 95D cells' migration and adhesion, by 50% at the concentration of 20 and 57 microg/ml, respectively. In the animal experiment, intraperitoneal administration of 75 mg/kg AA2P6L decreased the number of metastatic nodules by 62% and elevated the survival rate of C57BL/6 mice about onefold compared to the control group. CONCLUSION: AA2P6L, a lipophilic AA derivative with antioxidation, is shown to be a potent antimetastatic agent through the inhibition of tumor invasion. These results support future investigations on the feasibility of cancer chemotherapy with AA2P6L.
PURPOSE:Ascorbic acid (AA), the natural antioxidant, has been demonstrated to exert an antimetastatic action; however, AA is quite unstable in physiological condition. The aim of the present study is to investigate the stability, the antioxidation and the antimetastatic effects of three lipophilic AA derivatives in vitro as well as in vivo. METHODS: The 95D cells were treated with ascorbic acid-2-O-phosphate-6-O-laureate (AA2P6L), ascorbic acid-2-O-phosphate-6-O-myristate (AA2P6M) and ascorbic acid-2-O-phosphate-6-O-stearate (AA2P6S). AA derivatives' stability in medium under cell culture condition, in the presence and in the absence of 95D cells, was assessed by high-performance liquid chromatography assay. Cell viability and intracellular oxidative stress were measured by MTT assay and CDCFH assay, respectively. Wound healing assay and cell adhesion assay were used to investigate the antimetastatic activities against 95D cells in vitro, and the C57BL/6 mice model was used to evaluate the antimetastatic action in vivo. RESULTS: All the three AA derivatives exhibited excellent stability, significantly different from AA. Results of MTT assay showed that IC(50) values of the cytotoxicity of those AA derivatives, namely AA2P6L, AA2P6M and AA2P6S, were 38.46, 28 and 22.97 microg/ml, while the CDCFH assay indicated that EC(50) values of antioxidant effects on 95D cells were 31.12, 33.51 and 38.31 microg/ml, respectively. Through the ratio of IC(50) vs EC(50) for AA derivatives, AA2P6L was demonstrated to be the most effective AA derivative, which retained the antioxidant ability as well as low cytotoxicity. AA2P6L dose-dependently inhibited 95D cells' migration and adhesion, by 50% at the concentration of 20 and 57 microg/ml, respectively. In the animal experiment, intraperitoneal administration of 75 mg/kg AA2P6L decreased the number of metastatic nodules by 62% and elevated the survival rate of C57BL/6 mice about onefold compared to the control group. CONCLUSION: AA2P6L, a lipophilic AA derivative with antioxidation, is shown to be a potent antimetastatic agent through the inhibition of tumor invasion. These results support future investigations on the feasibility of cancer chemotherapy with AA2P6L.