This study reveals that the c-Myc oncogene suppresses miR-23a and miR-23b, leading to increased expression of mitochondrial glutaminase (GLS). This enhances glutamine metabolism, which is crucial for energy production and glutathione synthesis in cancer cells. The research shows that Myc regulates GLS through miRNA suppression, linking Myc's role in metabolism to energy and reactive oxygen species (ROS) homeostasis. Myc is a transcription factor that promotes cell proliferation and influences mitochondrial function. The study used human B cells and prostate cancer cells to demonstrate that Myc induces GLS expression, which is essential for cell growth. When GLS levels were reduced, cell proliferation decreased, indicating GLS's importance in Myc-driven cell growth. The study also found that glutamine deprivation reduced ATP levels and increased ROS, leading to cell death. This was mitigated by supplementing with oxaloacetate and N-acetylcysteine, suggesting that GLS-mediated glutamine metabolism is vital for cell survival. Further, the research shows that Myc directly represses miR-23a and miR-23b, which target GLS. This regulation occurs at the post-transcriptional level, with miR-23a and miR-23b being suppressed by Myc. The suppression of miR-23a and miR-23b leads to increased GLS expression, enhancing glutamine metabolism. The study also found that Myc induces the expression of the glutamine transporter SLC7A5, further supporting the role of glutamine metabolism in cancer cells. The findings highlight a regulatory pathway where Myc suppresses miR-23, leading to increased GLS and glutamine metabolism, which is critical for cancer cell growth and survival. This provides a mechanism linking Myc, miRNAs, and glutamine metabolism in human cancers.This study reveals that the c-Myc oncogene suppresses miR-23a and miR-23b, leading to increased expression of mitochondrial glutaminase (GLS). This enhances glutamine metabolism, which is crucial for energy production and glutathione synthesis in cancer cells. The research shows that Myc regulates GLS through miRNA suppression, linking Myc's role in metabolism to energy and reactive oxygen species (ROS) homeostasis. Myc is a transcription factor that promotes cell proliferation and influences mitochondrial function. The study used human B cells and prostate cancer cells to demonstrate that Myc induces GLS expression, which is essential for cell growth. When GLS levels were reduced, cell proliferation decreased, indicating GLS's importance in Myc-driven cell growth. The study also found that glutamine deprivation reduced ATP levels and increased ROS, leading to cell death. This was mitigated by supplementing with oxaloacetate and N-acetylcysteine, suggesting that GLS-mediated glutamine metabolism is vital for cell survival. Further, the research shows that Myc directly represses miR-23a and miR-23b, which target GLS. This regulation occurs at the post-transcriptional level, with miR-23a and miR-23b being suppressed by Myc. The suppression of miR-23a and miR-23b leads to increased GLS expression, enhancing glutamine metabolism. The study also found that Myc induces the expression of the glutamine transporter SLC7A5, further supporting the role of glutamine metabolism in cancer cells. The findings highlight a regulatory pathway where Myc suppresses miR-23, leading to increased GLS and glutamine metabolism, which is critical for cancer cell growth and survival. This provides a mechanism linking Myc, miRNAs, and glutamine metabolism in human cancers.