Dual-Targeting iRGD-Functionalized Pentablock Copolymer Nanosystem for miR-345-5p and Gemcitabine Delivery to Pancreatic Tumors

Effective therapies for pancreatic ductal adenocarcinoma (PDAC) have remained limited. Conventional chemotherapies for pancreatic cancer (PC) suffer from dose-limiting toxicities and limited efficacy due to drug resistance, poor biodistribution, and extensive desmoplasia. Targeted delivery of microRNAs to modify the tumor microenvironment, in combination with chemotherapeutics, can enhance outcomes by mitigating off-target toxicity and reducing fibrosis and drug resistance associated with PC therapies. To address these challenges, we developed a tumor-guided dual-targeting nanosystem for the codelivery of miR-345 and gemcitabine. This system leverages the intrinsic chemistry of pentablock copolymers for selective endolysosomal escape in tumor cells as well as targeting through functionalization with the tumor-penetrating peptide iRGD (a multifunctional construct referred to as mGP-i). The mGP-i nanosystem exploits both passive and active targeting mechanisms within the tumor microenvironment to enhance the selective uptake and synergistic activity of miR-345 and gemcitabine in pancreatic tumors. The mGP-i nanosystem exhibited stability against RNase degradation and serum proteins for 24 h, with rapid release of gemcitabine over 48 h and prolonged miR-345 release over 1 week. In vivo biodistribution studies following intravenous administration in mice bearing subcutaneous PC tumors showed rapid and selective accumulation of mGP-i within tumor tissues. In an orthotopic syngeneic pancreatic tumor mouse model, mGP-i treatment significantly reduced tumor burden and metastasis compared with the control. Immunohistochemical analysis of mGP-i-treated tumors revealed reduced fibrosis and lower expression of the proliferation marker Ki-67, alongside increased TUNEL-positive cells, indicating apoptosis. Moreover, E-cadherin expression increased, while vimentin expression decreased, suggesting a transition toward a less invasive phenotype with reduced metastatic potential. These findings highlight mGP-i as a promising platform for tumor-targeted combination therapies in pancreatic cancer.