Pinus maritima Extract Induces Apoptosis in Human Malignant Melanoma Cells via ROS/Caspase-3 Signaling

Melanoma is the most aggressive type of skin cancer due to its rapid metastasis with a high recurrence rate following conventional therapy. Pine bark extract (PBE) from Pinus maritima contains numerous phenolic compounds and functions as a potent antioxidant. The present study aimed to analyze the potential anticancer properties of PBE on human malignant melanoma A375 cells. The chemical composition of PBE was determined by high-performance liquid chromatography/photodiode array detector. The effects of PBE on cell death, migration, and invasion were determined using xCELLigence Technology real-time cell analysis. Annexin/propidium iodide flow cytometry and Hoechst 33342 staining were conducted to detect cell apoptosis. PBE induced apoptosis and inhibited cell migration and invasion. Cleaved caspase-3 expression and activity were significantly increased (P < 0.01) in cells treated with PBE compared with control cells. PBE ameliorated hydrogen peroxide (H₂O₂)-induced reactive oxygen species (ROS) formation. Treatment of the cells with PBE in the presence of H₂O₂ led to significant (P < 0.001) reduction of matrix metallopeptidase-9, which is a mediator responsible for advanced melanoma. PBE induces A375 programmed cell death and suppresses cellular invasion by attenuating the ROS-dependent pathway associated with MMP-9 reduction.