Up-regulated SLC25A39 promotes cell growth and metastasis via regulating ROS production in colorectal cancer.

Abstract

Background: The mitochondrial transporter SLC25A39 has been implicated in the import of mitochondrial glutathione (mGSH) from the cytoplasm, crucial for mitigating oxidative stress and preserving mitochondrial function. Despite the well-established involvement of mitochondria in cancer, the functional impact of SLC25A39 on CRC progression remains elusive. Methods: The mRNA and protein expressions were detected by PCR, immunohistochemistry, and Western blot, respectively. Cell activity, cell proliferation, colony formation, and apoptosis were measured by CCK8 assay, EdU incorporation assay, plated colony formation assay, and flow cytometry, respectively. Cell migration was detected by wound healing and transwell chamber assay. The tumor microenvironment (TME), immune checkpoint molecules, and drug sensitivity of CRC patients were investigated using R language, GraphPad Prism 8 and online databases. Results: Here, we report a significant upregulation of SLC25A39 expression in CRC. Functional assays revealed that overexpression of SLC25A39 promoted CRC cell proliferation and migration while inhibiting apoptosis. Conversely, SLC25A39 knockdown suppressed cell growth and migration while enhancing apoptosis in vitro. Additionally, reduced SLC25A39 expression attenuated tumor growth in xenograft models. Mechanistically, elevated SLC25A39 levels correlated with reduced reactive oxygen species (ROS) accumulation in CRC. Furthermore, bioinformatic analyses unveiled the high SLC25A39 levels was associated with decreased expression of immune checkpoints and reduced responsiveness to immunotherapy. Single-cell transcriptomic profiling identified diverse cellular expression patterns of SLC25A39 and related immune regulators. Lastly, drug sensitivity analysis indicated potential therapeutic avenues targeting SLC25A39 in CRC. Conclusion Our findings underscore the pivotal role of SLC25A39 in CRC progression and suggest its candidacy as a therapeutic target in CRC management.