Anti-cancer properties of the methanol extract of Boswellia serrata gum resin: Cell proliferation arrest and inhibition of angiogenesis and metastasis in BALB/c mice breast cancer model

Boswellia serrata is a medicinal plant with immense potential in combating cancer. Since many cancers therapeutics have their roots in natural products, we investigated the inhibitory effect of B. serrata gum resin alcoholic extract (BSE) on tumor growth, metastasis and angiogenesis in 4T1 breast cancer mouse model. Cell viability of BSE on triple negative cancer cell line, 4T1, was measured by MTT assay. In the anti-breast cancer study, female BALB/c mice in four groups (n=5) were implanted into the mammary fat pad with 4T1 cells (1×105 cells/0.1 ml) and treated by BSE (50, 150 and 250mg/kg) and distilled water for 21 days. Anti-proliferation and anti-angiogenesis effects of BSE in tumor tissues were evaluated by immunohistochemical (IHC) analysis for Ki-67 and CD31 expression. The metastatic rate was investigated in the liver and lung tissues by histopathological analysis. In in-vitro toxicity study, 4T1 cells line were sensitive to BSE treatment with reduced cell viability. BSE suppression of 4T1 tumor growth correlated with reduced cell proliferation as revealed by IHC analysis for Ki-67 expression. Analyses of the vasculature in the tumor tissues indicated smaller vessel area in BSE250 group compared to control tumors based on IHC for angiogenesis marker CD31. BSE only significantly decreased the metastatic rate in the lung tissue. From the outcome of our investigation, it is possible to conclude that BSE induces cell-specific cytotoxicity and suppresses cell proliferation, angiogenesis and metastasis rate in breast cancer cells and can be effective for advanced breast cancer.