Multifunctional nanoparticle-mediated targeting of metabolic reprogramming and DNA damage response pathways to treat drug-resistant triple-negative breast cancer.

Multi-drug resistance and immunosuppressive triple-negative breast cancer (TNBC) is triggered by the Warburg effect, which promotes homologous recombination repair (HRR) and upregulates expression of P-glycoprotein (P-gp), in turn preventing DNA damage from chemotherapy and creating an immunosuppressive microenvironment. It is therefore of clinical relevance to develop an effective delivery system that targets metabolic reprogramming and DNA damage response pathways for the treatment of drug-resistant TNBC. Herein, a P-gp-inhibiting and GSH-responsive multifunctional drug carrier targeting integrin αvβ3 was synthesised for the delivery of Lonidamine-prodrug (M1, glycolysis inhibitor) and Senaparib (Se, Poly [ADP-ribose] polymerase inhibitor). The nanodrug delivery system (iPR@M1/Se nanoparticles) exhibit effective tumour penetration and P-gp inhibition, effectively inducing DNA damage and apoptosis in Olaparib-resistant TNBC cells in vitro, as well as a higher tumour inhibitory rate compared with that of Se (81.82 % ± 2.31 % vs 43.91 % ± 4.65 %) in vivo. Mechanistically, iPR@M1/Se nanoparticles not only reshaped the immunosuppressive microenvironment resulting from tumour glycolysis, but also downregulated the expression of HRR-related protein, fostering the cytoplasmic accumulation of DNA damage fragments, which induced activation of the cyclic GMP-AMP synthase (cGAS)/stimulator of interferon gene (STING) pathway. Experimental results show that iPR@M1/Se nanoparticles effectively promote dendritic cell maturation and T lymphocyte activation, which elicits long-term immune memory responses, and prevents tumour recurrence and lung metastasis. Therefore, these multifunctional nanoparticles have great potential and provide a clinically relevant and valuable option for Olaparib-resistant TNBC.