Green-Synthesized Silver Nanoparticles from <i>Penicillium oxalicum</i> with Antibreast Cancer Activities <i>In Vitro</i> and <i>In Vivo</i>

The present study investigates the antibreast cancer potential of silver nanoparticles derived from the fungal endophyte <i>Penicillium oxalicum</i> (POAgNPs) using both <i>in vitro</i> and <i>in vivo</i> models. High-content analysis (HCA) demonstrated that POAgNPs significantly altered cellular and nuclear morphology, and we noted reduced cell impedance in human breast cancer cells MDA-MB-231 and MCF-7, indicating potent cytotoxicity. POAgNPs induced cell cycle arrest in the sub-G1 phase and promoted reactive oxygen species (ROS) generation, suggesting ROS-mediated apoptosis. Release studies confirmed efficient POAgNPs release at acidic pH (5.5), mimicking the tumor microenvironment, while the cellular uptake assay showed dose-dependent cytotoxicity. Moreover, POAgNPs exhibited antiangiogenic activity in the chick chorioallantoic membrane assay, indicating their potential to inhibit tumor neovascularization. <i>In vivo</i>, POAgNPs treatment mitigated the carcinogenic effects of 7,12-dimethylbenz[<i>a</i>]anthracene (DMBA) in breast tumor-bearing rats, as demonstrated by improved mammary tissue histology and significant restoration of oxygen saturation, total hemoglobin concentration, and reduced tumor vascularity measured via photoacoustic imaging (PAI). Biochemical assays revealed that POAgNPs helped restore the metabolic balance and oxidative status. Gene expression analysis showed upregulation of pro-apoptotic markers (<i>CASPASE 8</i> and <i>P53</i>) and downregulation of antiapoptotic <i>BCL-2</i> and the glucose transporter gene <i>SLC2A1</i>. Increased Caspase-3 activity further confirmed apoptosis induction. Collectively, these findings highlight the promise of POAgNPs as an effective antibreast cancer agent, warranting further research toward their development as a targeted nanotherapeutic.