Resveratrol (trans-3,4’,5-trihydroxystibene, Res), a phytoalexin found in grapes, elicits antioxidant and anti-inflammatory activity and has been shown to inhibit the multistage carcinogenesis process. The present study aims at verifying the potential chemopreventive activity of Res by a pattern of in vitro tests. The modified BALB/c 3T3 cell transformation assay was performed in order to evaluate the ability of resveratrol to inhibit the 3-MCA induced cell transformation, by acting as a suppressing agent. Aiming of analyzing possible cytotoxic effects, Res was previously tested in a wide range of concentrations (10-9-10-4 M) to assess their ability to affect the plating efficiency and the proliferation rate of BALB/c 3T3 clone A31 cells. In the anti-transformation assay, carcinogen-treated BALB/c-3T3 cells were chronically exposed to various doses of Res (10-7- 10-5 M) throughout the duration of the experiment. The chronic treatment significantly reduced the transformation frequency of 3-MCA–treated BALB/c 3T3 cells and the inhibition of foci occurrence was related to the assayed dose. The effects of Res on the proliferation rates of malignant cells were also evaluated. Because of the estrogenic activity of Res, human breast (MCF-7 and HuMi-TTu-2) and colon carcinoma (HT29 and Caco-2) cell lines, differing for the estrogen receptor expression, were chosen as eligible targets. Based on the cell viability assay, Res induced a dose-dependent inhibitory effect on the growth of both mammary cell lines with a GI50 of ~ 7.5 x 10-5 µM, whereas the GI50 calculated for the colon cell lines was ~ 5 x 10-5 µM. The toxicological profile, evaluated in both cytotoxicity and proliferation assay, was strongly suggestive of apoptosis induction. Anchorage independent growth has been widely used as a marker of neoplastic transformation and is closely related to cell tumorigenicity. Res induced a dose-related suppression of the clonogenicity of the assayed cell lines. 10-5 µM Res, the effective dose in the anti-transformation assay, was also able to exert a significant inhibition of the cell ability to colonize soft agar. Results give evidence for the feasibility of the proposed in vitro tests battery in vitro screening of candidate chemopreventive agents and for qualifying these compounds to further evaluation in clinical studies.
In vitro models to assess toxicity and efficacy of resveratrol, a natural promising tumor chemopreventive agent.
GRILLI, SANDRO;MASCOLO, MARIA GRAZIA;SILINGARDI, PAOLA;HORN, WOLFANGO;CHIOZZOTTO, DANIELA;VACCARI, MONICA;COLACCI, ANNAMARIA
2004
Abstract
Resveratrol (trans-3,4’,5-trihydroxystibene, Res), a phytoalexin found in grapes, elicits antioxidant and anti-inflammatory activity and has been shown to inhibit the multistage carcinogenesis process. The present study aims at verifying the potential chemopreventive activity of Res by a pattern of in vitro tests. The modified BALB/c 3T3 cell transformation assay was performed in order to evaluate the ability of resveratrol to inhibit the 3-MCA induced cell transformation, by acting as a suppressing agent. Aiming of analyzing possible cytotoxic effects, Res was previously tested in a wide range of concentrations (10-9-10-4 M) to assess their ability to affect the plating efficiency and the proliferation rate of BALB/c 3T3 clone A31 cells. In the anti-transformation assay, carcinogen-treated BALB/c-3T3 cells were chronically exposed to various doses of Res (10-7- 10-5 M) throughout the duration of the experiment. The chronic treatment significantly reduced the transformation frequency of 3-MCA–treated BALB/c 3T3 cells and the inhibition of foci occurrence was related to the assayed dose. The effects of Res on the proliferation rates of malignant cells were also evaluated. Because of the estrogenic activity of Res, human breast (MCF-7 and HuMi-TTu-2) and colon carcinoma (HT29 and Caco-2) cell lines, differing for the estrogen receptor expression, were chosen as eligible targets. Based on the cell viability assay, Res induced a dose-dependent inhibitory effect on the growth of both mammary cell lines with a GI50 of ~ 7.5 x 10-5 µM, whereas the GI50 calculated for the colon cell lines was ~ 5 x 10-5 µM. The toxicological profile, evaluated in both cytotoxicity and proliferation assay, was strongly suggestive of apoptosis induction. Anchorage independent growth has been widely used as a marker of neoplastic transformation and is closely related to cell tumorigenicity. Res induced a dose-related suppression of the clonogenicity of the assayed cell lines. 10-5 µM Res, the effective dose in the anti-transformation assay, was also able to exert a significant inhibition of the cell ability to colonize soft agar. Results give evidence for the feasibility of the proposed in vitro tests battery in vitro screening of candidate chemopreventive agents and for qualifying these compounds to further evaluation in clinical studies.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
