Smart pH-Sensitive Nanogels for Enhancing Synergistic Anticancer Effects of Integrin αvβ3 Specific Apoptotic Peptide and Therapeutic Nitric Oxide

Apoptotic peptide (kla), which can trigger the mitochondria-mediated apoptotic programmed cell death, has been widely recognized as a potential Anticancer agent. However, its therapeutic potential has been significantly impaired by its poor biostability, lack of tumor specificity, and particularly low cellular uptake. Herein, a linear peptide Arg-Trp-d-Arg-Asn-Arg (RWrNR) was identified as an Integrin α_vβ₃ specific ligand with a nanomolar dissociation constant (K_d = 0.95 nM), which can greatly improve kla antitumor activity (IC₅₀ = 8.81 μM) by improving its cellular uptake, compared to the classic integrin-recognition motif c-RGDyK (IC₅₀ = 37.96 μM). Particularly, the RWrNR-kla conjugate can be entrapped in acidic sensitive nanogels (RK/Parg/CMCS-NGs), composed of poly-l-arginine (Parg) and carboxymethyl chitosan (CMCS, pI = 6.8), which can not only carry out controlled release of RWrNR-kla in response to the tumor acidic microenvironment, and consequently enhance its tumor specificity and cell internalization, but also trigger tumor-associated macrophages to generate nitric oxide, leading to enhanced synergistic Anticancer efficacy. Importantly, RK/Parg/CMCS-NGs have been proven to effectively activate the Apoptosis signaling pathway in vivo and significantly inhibit tumor growth with minimal adverse effects. To summarize, RK/Parg/CMCS-NGs are a promising apoptotic peptide-based therapeutics with enhanced tumor accumulation, cytosolic delivery, and synergistic Anticancer effects, thereby holding great potential for the treatment of malignant tumors.