Inhibitory Effect of Viola odorata Extract on Tumor Growth and Metastasis in 4T1 Breast Cancer Model

Viola odorata as a medical herb is used in liver disorders and relieving cancer pain. In the present study, the cytotoxic, antioxidant, and anti-metastatic properties of Viola odorata hydro-alcoholic extract (VOE) were investigated in 4T1 breast cancer model. After treatment of 4T1 breast cancer cells with VOE, cell viability was measured by MTT assay. The implanted mice were treated with different concentration of VOE (50, 150 and 250 mg/kg) for 21 days. Levels of lactate dehydrogenase (LDH), γ -glutamyl transferase (GGT), alkaline phosphatase (ALP), carcinoembryonic antigen (CEA) and cancer antigen 15-3(CA15-3) in serum, and also catalase (CAT) and superoxide dismutase (SOD) activities in tumor tissue were measured. Metastatic rate was investigated in liver, spleen and lung tissues. VOE decreased cell viability of 4T1 cells, significantly. VOE significantly inhibited the cell proliferation, but not vasculature in the tumors that revealed by immunohistochemical analysis for Ki-67 and CD31 expression, respectively. VOE increased the Bax/Bcl-2 ratio in VOE250-treated group compared to control group. Serum analysis showed that treatment with 250 mg/kg of VOE significantly reduced LDH (not ALP and GGT) levels compared to controls. No linear correlation was found between the values of CEA and CA15-3 with tumor size. The rate of CAT activity was increased in VOE250-treated rats whereas, CAT and SOD activities were reduced in VOE50 group. VOE250 significantly decreased the metastatic rate in liver and lung compared to the other doses of VOE. Consequently, Viola odorata has cytotoxic effects on 4T1 cells and affects antioxidant activity and metastasis in breast cancer.