RESUMO
Saikosaponin A (SSa) is isolated from the dried root of Radix Bupleuri, an herb widely used in traditional Chinese medicine, exerting antitumor activities. The T helper cell type 1(Th1)/Th2 balance is associated with antitumor immunity in breast cancer. The present study aimed to investigate the effects of SSa on Th1/Th2 balance in breast cancer and to explore the underlying mechanisms. Breast cancer in rats was induced by intragastrical administration of 7,12-dimethyl-benz[a] anthracene once (100 mg/kg). At d91, the rats suffering from tumors were randomly divided into three groups and treated with vehicle solution (control group), tamoxifen (TAM group), and SSa (SSa group) daily for 56 days, respectively. The tumor volume reduction ratio and tumor cell proliferation were detected to assess the antitumor effect of SSa. The positive staining numbers of CD8+ and CD4+ T cells infiltrated in breast tumors were measured by immunohistochemistry to evaluate the antitumor immunity of SSa. Cytokine levels in serum secreted by Th1 cells [interferon gamma (IFN-γ), interleukin (IL)-12] and Th2 cells (IL-4, IL-10) were detected to evaluate Th1/Th2 balance. The related molecules of IL-12/signal transducers and activators of transcription 4 (STAT4) pathway were detected by immunohistochemistry staining, RT-PCR, and Western blot to explore the mechanisms of SSa. The results showed that, compared with the control group, SSa significantly inhibited tumor growth and tumor cell proliferation. SSa enhanced antitumor immunity, which was demonstrated as increased CD8+ T cells and CD4+ T cells infiltrated in tumors. SSa shifted Th1/Th2 balance toward Th1, which was confirmed as increased serum IFN-γ and IL-12 levels, while decreased serum IL-4 and IL-10 levels. SSa increased IL-12, IL-12 receptor, and phosphorylated STAT4 expressions to promote Th1 differentiation. In conclusion, the present work suggested that SSa could inhibit breast cancer growth by shifting Th1/Th2 balance toward Th1. The underlying mechanism may involve activation of the IL-12/STAT4 pathway that induced Th1 differentiation.
RESUMO
OBJECTIVE: To evaluate vitality principle in breast cancer rats by pharmacologically developing a model for anticancer surveillance. METHODS: The breast cancer in rats was replicated with 7,12-Dimethylbenz[a]anthracene (DMBA, i.g., 100 mg/kg) at d001. The anticancer surveillance was defined as the intervals between the primary sensitization and the first challenge stirred with complete Freund's adjuvant (CFA), the various intervals (k = 0.80) were dominated from d025 (600.00 h) to d095 (2288.82 h). The optimal surveillant status was confirmed with the median effective interval (EI50) from tumor volume regressive curve, for developing the pharmacodynamic model. The tumor and tumor infiltrating lymphocyte histopathology was used to confirm the immune surveillance being affected with CFA in breast cancer tumorigenesis. The availability of this model was confirmed with Shugan Liangxue prescription (SLP), from the vitality principle, and assured further from interleukin-12 levels. RESULTS: The regressive curve was set up between the intervals and tumor volumes, the EI50 in SLP-treated rats (1475.00 h, YSLP = 0.1026 + 0.8780/[1 + 10(27.1425-8.565x)]) was postponed, which was 1.87 multiple of the EI50 in CFA rats (791.40 h, y = -0.0525 + 0.9452/[1 + 10(30.4870-10.52x)], so did prepone the curve between the intervals and the immunological biomarker, serum interleukin-12 levels, the EI50 in SLP-treated rats (744.90 h, YSLP = -0.0145 + 0.7455/[1 + 10(52.09636-18.13x)]) be 0.78 multiple of the EI50 in CFA rats (960.10 h, YCFA = 0.2460 + 0.7270/[1 + 10 (-67.1546 + 22.52x)]), this immunological action being mediated the anticancer prognosis. Tumor histology was confirmed the more tumor infiltrating lymphocytes activated in SLP rats with CFA stirred immunity than rats only received CFA. CONCLUSION: The model for anticancer surveillance was pharmacologically established as the optimal interval (791.40 h) between the primary sensitization and the first challenge stirred with complete Freund's adjuvant. This available model was confirmed with SLP, from the vitality principle, for evaluating immunological effects against breast cancer.