Effect of thalidomide combined with tamoxifen on hormone levels and vascular-related growth factors in breast cancer-bearing mice

Abstract

Objective To investigate the effects of thalidomide combined with tamoxifen on hormone levels and vascular-related growth factors in breast cancer-bearing mice. Methods MCF-7 cells were used to establish a tumor-bearing mouse model of breast cancer. 48 mice were randomly divided into control group, tamoxifen group (25 mg/kg), thalidomide group (50 mg/kg), thalidomide combined with tamoxifen group for 12 mice in each group. Continuous gavage for 2 weeks, once per day. The tumor weight, tumor inhibition rate, hormone level, and blood vessel-related growth factors were compared. Results (1) Tumor weight and tumor inhibition rate: The tumor weight of the model control group, tamoxifen group, thalidomide group, thalidomide combined with tamoxifen group breast cancer tumor-bearing mice were (2.52±0.45), (2.07±0.40), (2.12±0.43), (1.15±0.35) g, the tumor inhibition rates of the tamoxifen group, thalidomide group, thalidomide and tamoxifen group were (17.86±3.12)%, (15.87±2.54)%, and (54.37±6.24)%. The tumor weight of thalidomide combined with tamoxifen breast cancer-bearing mice was significantly lower than that of tamoxifen group and thalidomide group, and the tumor inhibition rate was significantly higher than that of tamoxifen group and thalidomide group (t=5.996, 18.129, 6.061, 19.796, P<0.05, P<0.01). (2) Hormone levels: The mean luminosity values of estrogen receptor-α (ER-α) in the model control group, tamoxifen group, thalidomide group, thalidomide combined with tamoxifen group were 0.712±0.015, 0.421±0.010, 0.385±0.012, 0.212±0.007, the mean photometric values of estrogen receptor-β (ER-β) were 0.105±0.005, 0.192±0.007, 0.178±0.006, and 0.245±0.008, respectively. The average luminosity value of ER-α in thalidomide combined with tamoxifen group was significantly lower than that in tamoxifen group and thalidomide group, the average luminosity value of ER-β was significantly higher than that of tamoxifen group and thalidomide group (t=38.366, 17.271, 40.160, 23.209, P<0.01). (3) Vascular growth-related growth factor: serum vascular endothelial growth factor (VEGF) levels in model control group, tamoxifen group, thalidomide group, thalidomide combined with tamoxifen group were (125.12±22.34), (96.36±13.25), (84.42±11.35), (72.12±9.45) ng/L, the basic fibroblast growth factor (bEGF) content was (18.32±3.24), (14.21±2.35), (12.12±2.10), (10.32±1.45) ng/L, the levels of endostatin (ES) were (12.32±1.45), (14.65±1.62), (16.12±2.02), and (18.32±2.42) μg/L. The serum levels of VEGF and bEGF in thalidomide combined with tamoxifen group were significantly lower than those in tamoxifen group and thalidomide group, the ES content was significantly higher than that of the tamoxifen group and the thalidomide group (t=5.160, 4.880, 4.366, 2.885, 2.443, 2.418, P<0.05). Conclusion Thalidomide combined with tamoxifen may inhibit the growth of breast cancer in bearing mice. Key words: Breast cancer; Thalidomide; Tamoxifen; Estrogen; Vascular growth factor