The study of antitumor activity of C-phycocyanin from Limnothrix sp. NS01 at cellular and molecular levels

C-phycocyanin (C-PC) is a blue color photosynthetic pigment which is found in cyanobacteria. It is a water-soluble protein which has anticancer, antioxidant and anti-inflammatory properties. In the current study, therapeutic properties of C-phycocyanin from an indigenous cyanobacterial strain Limnothrix sp. NS01 were investigated. The inhibitory effects of high purity C-PC on the proliferation of human breast cancer cells (MCF-7) were detected by spectrofluorimetry, flow cytometry and Real-time PCR. Flow cytometric analysis of cells treated with C-PC by Annexin V/PI induces apoptosis in MCF-7 cells. The results obtained from propidium iodide (PI) flow cytometric assay showed that MCF-7 cells treated with 192 and 113.9 μM of C-PC for 24 and 72 h could induce cell cycle arrest at G2 and S phases, respectively. In order to evaluate the potential direction of induced apoptosis, parameters of mitochondrial oxidative stress were evaluated. The results of our study showed that treatment of MCF-7 cells with PC increased the production of reactive oxygen species (ROS) and LPO level but decreased ATP and mitochondrial membrane potential (ΔΨm). In addition, our results indicate that the ratio of GSH to GSSG is reduced over time. The decreased proteins such as STAT3, Cyclin D1 and BCL2 were identified in MCF-7 cells after PC treatment by Real-time PCR, indicating that the effects of C-PC on tumor cell apoptosis may be related to multiple target proteins. The results thus demonstrate that the mitochondrial pathway may be the main pathway for PC-induced apoptosis in MCF-7 cells.

کلیدواژه ها:

Cyanobacteria ، Phycocyanin ، Apoptosis ، mitochondrial oxidative Stress