Salicylates Promote ROS‐induced Endoplasmic Reticulum Stress Triggering Apoptosis on B16F10 Melanoma

Abstract

Endoplasmic reticulum stress (ERS) and activation response to this stress have been documented in several types of cancer, suggesting that these cells activate the stress response as a survival strategy. Thus, drugs that cause an imbalance in this response may impair cancer cell viability. Salicylates have proven preventive and anti‐tumor effects in various types of cancer. On regard of ERS, it has been reported to act as potent inhibitor of protein synthesis in rat islets and in the gastric mucosa of guinea pigs. Salicylates also activate ERS through PERK activation in human promonocytic cells. In addition, the treatment with salicylates is correlated to increased reactive oxygen species (ROS) production, probably due to the direct inhibition of catalase activity. Nevertheless, there is still no correlation among salicylates, ERS and cancer. The aim of the present work is to investigate a new mechanism for salicylic acid (SA) and acetylsalicylic acid (ASA) related to their antitumoral effects, which involves the induction of ERS by ROS, and corroborate the new perspectives for the use of these drugs. Melanoma B16F10 cell line was used in all experiments and treated with 10mM SA or ASA. We tested cell viability and apoptosis using Anexin V assay, and ROS production using DCFDA, both by cell sorting. Unfolded protein response (UPR) markers were evaluated by qPCR and Western blot analysis. The treatment of the cells with SA or ASA for 1 or 2 hours promoted an increase in ROS production, as well as in the mRNA levels of the UPR markers ATF4 and CHOP. Increased protein levels of other UPR markers, such as PERK, IRE1, ATF6, cleaved ATF6, BiP and CHOP, are detected within 24 hours of treatment with both drugs. Finally, the treatment triggers apoptosis, which was detected on its early stage after 24 hours. Taken together, our data indicate that treatment of melanoma B16F10 cells with SA or ASA reduces cell viability thought a ROS‐induced ERS mechanism.Support or Funding InformationFinancial support: FAPERJ, CAPES, CNPq