Objective: To explore the anti-tumor effects of resveratrol (Res) upon human skin squamous cell carcinoma A431 xenograft in nude mice and elucidate the regulatory mechanisms of survivin and caspase-3.
Methods: The model of human skin squamous cell carcinoma (A431) xenograft in nude mice was established. And the animals were randomly divided into saline-negative control, cyclophosphamide (CTX) positive control, Res high-, medium- and low-dosage and blank control groups (n = 10 each). After drug intervention, tumor-bearing mice were sacrificed. The tumor growth curve was plotted and the Res inhibition rate calculated by terminal tumor weight. The morphological changes of tumor cell among groups were observed by hematoxylin and eosin staining; cell apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling TUNEL; the impact of Res upon the protein expressions of survivin and caspase-3 in tumor issues was observed by Western blot. Analysis of variance and Pearson's correlation were employed for statistical analyses.
Results: (1) By the end of treatment, the tumor volume of CTX, Res high-, medium-, low-dosage, saline-negative control and blank control groups were (1154 ± 255), (1002 ± 115), (1207 ± 176), (1342 ± 211), (1642 ± 226), (1564 ± 156) mm(3) respectively, and tumor weight of CTX, Res high-, medium-, low-dosage, saline-negative control and blank control groups (1.84 ± 0.30), (1.72 ± 0.39), (1.96 ± 0.40), (2.67 ± 0.73), (3.16 ± 0.52), (3.33 ± 0.59) g respectively. Through analysis of variance, the tumor volume and weight of Res high-, medium-, low-dosage groups were smaller than those of saline-negative control and blank control groups (all P < 0.05). The inhibition rate of Res high-, medium- and low-dosage groups were 45.57%, 37.97% and 15.51% respectively. (2) The apoptosis index of the above groups were 36.79% ± 8.86%, 33.15% ± 6.00%, 18.09% ± 3.92%, 10.53% ± 4.20%, 3.87% ± 1.63%, 2.73% ± 1.61%. Through analysis of variance, the apoptosis index of Res groups were higher than those of saline-negative control and blank control groups (all P < 0.05). (3) The protein expression of survivin/β-actin of each group were 0.48 ± 0.20, 0.19 ± 0.11, 0.22 ± 0.12, 0.28 ± 0.24, 0.98 ± 0.41, 0.85 ± 0.34. The protein expression of caspase-3/β-actin of each group were 0.42 ± 0.09, 0.31 ± 0.10, 0.31 ± 0.07, 0.22 ± 0.08, 0.14 ± 0.04, 0.13 ± 0.05 respectively. Through analysis of variance, the protein expression of survivin of Res groups was lower than those of the saline-negative control and blank control groups (all P < 0.05). And the protein expression of caspase-3 of Res groups were higher than those of the saline-negative control and blank control group (all P < 0.05). Through Pearson's analysis, the protein expression of survivin and caspase-3 had no correlation (r = -0.279, P > 0.05).
Conclusions: Res inhibits the growth of human skin squamous cell carcinoma A431 xenograft in nude mice. And its mechanism may be associated with the apoptosis of tumor cell through the depression of survivin and the activation of caspase-3.