Apoptosis Induction Through Increased TRPV1 Activation by Synergic Effect of Melatonin and Doxorubicin in Human Osteosarcoma and Chondrosarcoma Cell Lines

Abstract

Aim: We aimed to reveal the role of doxorubicin (Dox), melatonin (Mel) and transient receptor potential Vanilloid 1 (TRPV1) channels in bone and cartilage cancer cells during the treatment process. Human Bone Osteosarcoma (Saos-2/An1) and Human Chondrosarcoma (Hs 819.T) cell lines were used to prepare in-vitro experiment models. Methods: Both cell lines were cultured at 37°C. We have separated each cell line into five groups as follows: Controls, Dox, Dox+Capsazepine (Cpz), Dox+Melatonin (Mel), and combined Dox+Mel+Cpz given group. Capsaicin and capsazepine were added to cell culture mediums to activate or inactivate the TRPV1 channels, respectively. Cytosolic calcium, apoptosis, intracellular reactive oxygen, mitochondrial depolarization, caspase-3 and caspase-9 levels were measured. Results: Increased apoptotic activity was detected in doxorubicin given cell lines (Group II) when compared with the controls (p˂0.001). There was also a significantly higher apoptotic level in Dox+Mel group (Group IV), when compared with only Dox given group (p˂0.001). TRPV1 inhibition applied groups (Group III and V) have had lower apoptotic levels than other drug administered groups (p˂0.001). Conclusion: This study has indicated that apoptotic effects of Dox and Mel on both osteosarcoma and chondrosarcoma were strictly associated to TRPV1 channels, and that TRPV1 channels played an important role in whole mitochondria dependent pathways of apoptosis, which in turn may lead to increased intracellular Ca+2 levels and mitochondrial depolarization.