N-methylated YKWYYRGAA nano-chitosan conjugate induces mitochondria-mediated apoptosis, suppressing NRAS-mutant lung carcinoma.

Treating non-small cell lung cancer (NSCLC), particularly aggressive NRAS-mutant forms, remains challenging due to limited drug efficacy, systemic toxicity, and the rapid development of drug resistance. Current therapies often fall short in targeted delivery, leading to off-target effects and insufficient drug concentrations at tumor sites. The need for multi-mechanistic approaches that can simultaneously enhance cellular uptake, regulate key oncogenic pathways, and overcome resistance mechanisms is critical. This study explores a novel peptide-decorated nanocarrier to address these gaps, leveraging mitochondrial targeting and immunomodulation.

Researchers modulated the mitochondria-targeting YKWYYRGAA (P1) peptide into N-methylated YKWYYRGAA (P2) and N-dimethylated YKWYYRGAA (P3) to enhance nano-chitosan conjugates. Spray-dried chitosan nanoparticles, incorporating P1, P2, or P3, underwent physicochemical testing. Their efficacy was evaluated in NRAS-mutated H1299 cells for permeability, cytotoxicity, apoptosis, cell cycle arrest, drug resistance, metastasis, and immunomodulation. In vivo pharmacokinetics and pharmacodynamics were assessed for the P2-grafted nanochitosan via an inhaled route, comparing it to P1 and P3 conjugates and controls.

Single N-methylation of YKWYYRGAA (forming P2) significantly enhanced cancer cell permeability, intracellular drug/nanoparticle uptake, and drug targeting, unlike P1 and P3, which were hindered by excessive ionic/hydrophobic interactions at the membrane. P2-grafted nanochitosan demonstrated sustained and pH-stimuli responsive release, leading to increased cytotoxicity. > P2-grafted nanochitosan induced mitochondria-mediated apoptosis with minimal necrosis, primarily through ROS activation and FasL-linked death pathways. It effectively suppressed mTOR and MAPK signaling, overcoming EGFR-resistance and EGFR mutation-independent tumorigenesis pathways. The conjugate mitigated drug resistance by downregulating P-gp (efflux receptor) and GSTP1 (degrading enzyme) expressions. Furthermore, it reversed epithelial-mesenchymal transition by upregulating E-cadherin and downregulating N-cadherin, snail, twist1, vimentin, ezrin, and MMP9. Immunological lung tissue lysis was reduced via MICA/ULBP1 suppression. In vivo, inhaled P2-grafted nanochitosan provided positive lung cancer recovery with reduced systemic exposure and minimal hematological/biochemical toxicities.