Targeted Folate-Chitosan Nanoformulations of Quercetin and Coriandrum sativum Reprogram Breast Cancer Hallmarks by Silencing Stemness, Cell Cycle, Angiogenic, and Metastatic Networks

Background/Objectives: This study engineered and evaluated a targeted, folate-functionalized chitosan nanoparticle (CS-FA NP) delivery system to enhance the therapeutic efficacy of standard quercetin and Coriandrum sativum seed extract against breast cancer. Methods: Phytochemical profiling confirmed a 14% crude yield for the methanolic extract, with gas chromatography–mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) identifying quercetin as the principal bioactive agent. The synthesized CS-FA NPs exhibited a core size of 7–20 nm, an average hydrodynamic diameter of 150–160 nm, a stable zeta potential of −55 mV, and high encapsulation efficiencies (87.2% for quercetin and 80.5% for coriander). Kinetic assessments confirmed a biphasic, diffusion-controlled release matching Higuchi matrix kinetics. Anticancer activity was evaluated in vitro using MTT cytotoxicity, Annexin V-FITC/PI apoptosis analysis, RT-qPCR, and ex vivo rat aortic ring assays, followed by validation in a syngeneic 4T1 mammary tumor mouse model. Results: In vitro, folate-receptor-targeted quercetin nanoparticles (T4) demonstrated superior, selective cytotoxicity, particularly against triple-negative MDA-MB-231 cells, while sparing normal fibroblasts. Annexin V-FITC/PI apoptosis profiling and ex vivo aortic ring assays revealed profound, cell-line-dependent programmed cell death and up to 90% inhibition of microvessel sprout outgrowth. Mechanistically, RT-qPCR verified that nano-formulations induced complete transcriptional silencing of NANOG, MMP-1, VEGFA, TSPAN8, TWIST, EMMPRIN, and CDK1, alongside marked upregulation of P27KIP1 and P21CIP1. In vivo, these nano-formulations successfully improved tumor-associated pathological features, reduced aggressive tumor spindle-cell proliferation, and suppressed elevated serum CA15-3 and arginase biomarkers. Conclusions: Folate-functionalized chitosan nano-formulations significantly enhanced the anticancer efficacy of quercetin and Coriandrum sativum seed extract through improved targeted delivery, potent antiproliferative, anti-angiogenic, and pro-apoptotic activities, together with favorable modulation of multiple molecular pathways associated with breast cancer progression. These findings support their potential as promising targeted nanotherapeutic strategies for breast cancer treatment.