The effect of MAPK inhibitors and ROS modulators on cell growth and death of H₂O₂-treated HeLa cells

Reactive oxygen species (ROS) influence the signaling of mitogen-activated protein kinases (MAPKs) involved in cell survival and death. In the present study, the toxicological effect of hydrogen peroxide (H₂O ₂) on HeLa cervical cancer cells was evaluated following treatment with MAPK inhibitors [MAP kinase or ERK kinase (MEK), c-Jun N-terminal kinase (JNK) or p38], N-acetyl cysteine (NAC) and propyl gallate (PG) (well-known antioxidants), or L-buthionine sulfoximine [BSO; an inhibitor of glutathione (GSH) synthesis]. Treatment with 100 μM H₂O₂ inhibited the growth of HeLa cells and induced cell death, which was accompanied by loss of the mitochondrial membrane potential (MMP; Δψm). H ₂O₂ did not induce any specific phase arrests of the cell cycle. ROS levels increased, while GSH levels decreased in H₂O ₂-treated HeLa cells after 1 and 24 h of treatment. The MAPK inhibitors enhanced H₂O₂-induced HeLa cell death, while only p38 inhibitor increased ROS levels. Both NAC and PG attenuated H ₂O₂-induced HeLa cell growth inhibition and death together with the suppression of ROS levels. BSO increased ROS levels in H ₂O₂-treated HeLa cells without increasing cell death. The levels of MMP (Δψm) loss and GSH depletion were not closely associated with the levels of apoptosis in HeLa cells treated with the MAPK inhibitors, NAC, PG or BSO, in the presence of H₂O₂. In conclusion, H₂O₂ induced HeLa cell growth inhibition and death. MAPK inhibitors generally enhanced H₂O₂-induced HeLa cell death. In particular, p38 inhibitor increased ROS levels in H₂O ₂-treated HeLa cells, while NAC and PG attenuated H₂O ₂-induced HeLa cell death by suppressing ROS levels.