Effects of antiapoptotic protein inhibitor-loaded nanoparticles on cancer cells

Evasion of apoptosis is a hallmark of cancer cells. Myeloid leukemia cell differentiation protein (MCL-1) is an anti-apoptotic protein of the B-cell lymphoma 2 (BCL-2) family that regulates cellular apoptosis. MCL-1 expression plays a key role in the survival of cancer cells and is therefore a promising target in cancer therapy. BH3 mimetic peptides targeting the conserved BH3 domains of MCL-1 and other antiapoptotic BCL-2 proteins are highly specific MCL-1 inhibitors. However, the use of peptides is limited due to their metabolic instability, degradation by cellular proteases, and difficulty in passing through cellular membranes. In this study, it was aimed to increase the cellular uptake and stability of MS1 peptide, a selective inhibitor of the antiapoptotic protein MCL-1, and accordingly, nanostructures containing MS1 peptide were formed using nanobiotechnological methods and the cytotoxic and apoptotic effects of these structures on cancer cells were investigated. In this context, Bim BH3 mimetic MS1 peptide was produced recombinantly fused with mNeonGreen fluorescent protein and polyhistidine. Two nanoparticular systems were prepared using this recombinant protein. The first is recombinant protein-based self-assembly nanoparticular systems. The second is polymeric nanoparticle systems in which this fusion protein is encapsulated. The cytotoxic effects of nanoparticles on cervical cancer (HeLa), lung cancer (A549) and breast cancer (MDA-MB-231) cell lines and healthy cell line (HUVEC) were analyzed by MTT assay. In addition, the apoptotic effects of nanoparticles were investigated by determining the expression levels of antiapoptotic and apoptotic proteins in the cells to which they were applied, by RT-PCR and Western blotting. As a result, new targeted drug candidate nanoparticles have been developed that have a specific cytotoxic effect against cancer cells and have been shown to induce apoptosis in these cells. In the future, the obtained data may contribute to the development of biotechnological drug formulations that can increase the success of therapeutic peptides in clinical applications.