Background/aim: The emerging antineoplastics Casiopeínas® induce uncoupling of the respiratory chain, production of reactive oxygen species (ROS), entry of Bax into mitochondria, and exit of Ca2+ and Bcl-2 from them, leading to apoptosis. This study aimed to elucidate whether BAX and BCL2 are necessary for apoptosis.
Materials and methods: We silenced BAX and BCL2 by CRISPR-Cas9, assessed ROS and calcium retention capacity (CRC) by spectrofluorometry, and caspase-3 with inmunoblotting in neuroblastoma (NB) cells and 3T3-L1 fibroblasts treated with cisplatin and Casiopeína IIIia (CasIIIia).
Results: We observed an increase in O2•- production only in BCL2KO NB cells treated with cisplatin (three-fold) and CasIIIia (five-fold), whereas the production of H2O2 in BCL2KO NB cells treated with cisplatin and CasIIIia increased five-fold and three-fold, respectively. The baseline calcium-retention capacity (CRC) was 1.7 relative fluorescence units (RFU) in both cell types. In BAXKO, cisplatin and CasIIIia increased CRC to ~2.3 RFU, and in BCL2KO, they decreased CRC to ~1.1 RFU. We did not detect caspase-3 in BAXKO NB cells.
Conclusion: Only BAX is essential for CasIIIia-induced apoptosis.
Keywords: BAX and BCL2 silencing; CRISPR/Cas9; Ca2+ retention capacity; Casiopeína IIIia; SK-N-SH cells; mPTP.
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