mTOR pathway targeted inhibition via Rapamycin-loaded PLGA nanoparticles for enhanced bladder cancer therapy

Abstract Bladder cancer remains a major clinical challenge due to high recurrence rates, metastatic potential, and the development of drug resistance driven by complex gene regulation. Targeting the PI3K/AKT/mTOR pathway is a promising strategy, as its dysregulation promotes tumor growth and survival. Rapamycin, Everolimus, Temsirolimus and Other ATP-competitive inhibitors work by binding to the mTOR protein and preventing it from activating downstream signaling pathways that control cell growth and division. However, the therapeutic potential of Rapamycin, an mTORC1 inhibitor, is limited by poor solubility, low bioavailability, and non-specific distribution. This study explores the use of poly (lactic-co-glycolic acid) nanoparticles to encapsulate Rapamycin for enhanced delivery and controlled release in bladder cancer therapy. Drug release followed the Korsmeyer-Peppas model, indicating sustained release behavior. In vitro cytotoxicity assays demonstrated that Rapa-PLGA NPs significantly reduced the IC50 compared to free Rapamycin in T24 bladder cancer cells. Wound healing assays revealed substantial inhibition of cancer cell migration. Gene expression analysis showed that Rapa-PLGA NPs effectively downregulated mTOR, HIF-α, BCL-2, and ABCC1, while upregulating FOXO1 and MAPK, promoting apoptosis and reducing drug resistance. These findings highlight the potential of Rapa-PLGA NPs to enhance Rapamycin’s therapeutic efficacy by integrating nanotechnology-driven delivery with gene regulatory mechanisms. This nanoparticle-based system presents a promising strategy for improving targeted bladder cancer therapy and overcoming drug resistance, warranting further in vivo investigation.