en Health Services, Quality of Life and Outcomes Original/Research Article <div style="text-align: justify;"><span style="font-size:16px;"><span style="font-family:Times New Roman;"><strong>Int</strong><strong>r</strong><strong>oduction</strong><strong>: </strong>Cancer is the second leading cause of death all over the world and breast cancer is the second common member of cancers worldwide. In this study, silver nanoparticles (Ag-NPs) were synthesized; using hydroethanolic extract of Cucurbita pepo<br> L. fruit and evaluated for their antiproliferative and apoptotic activities against MCF-7 cell line.<br> <strong>Methods</strong><strong>: </strong>Ag-NPs formation was characterized by ultraviolet-visible spectroscopy, energy dispersive spectroscopy (EDX), scanning electron microscopy (SEM), dynamic light scattering (DLS), and Fourier transform infrared (FTIR) spectroscopy. Cytotoxicity and apoptosis responses were evaluated by 3-[4,5-dimethylthiazole-2-yl]-2,5- diphenyltetrazolium bromide (MTT) and dual acridine orange/ethidium bromide (AO/ EB) fluorescent staining, respectively.<br> <strong>Results</strong><strong>: </strong>Our results demonstrated the formation of Ag-NPs by Cucurbita pepo L. fruit extract discoloration to dark black. This transformation revealed their slightly aggregated shapes to quasi-spherical form with a mean diameter of 104&thinsp;nm. The zeta potential value was -42.3 mV for any Ag-NPs. These results indicated the successful formation of Ag- NPs for cellular uptake. MTT results showed that Ag-NPs significantly decreased the viability and induced MCF-7 cells apoptosis in a dose-dependent manner; especially at concentrations of 50 and 250 &mu;g/mL.<br> <strong>Conclusions: </strong>In conclusion, according to the results of the present study, biologically synthesized Ag-NPs induce apoptotic and cytotoxic effects against breast cancer cell lines in a dose-dependent manner.</span></span></div> Cell Line, Breast Neoplasms, Nanoparticles, Green Chemistry Technology, Cucurbita 1 10 http://mcijournal.com/browse.php?a_code=A-10-525-1&slc_lang=en&sid=1 Leila Soltani leilasoltani7@yahoo.com 10031947532846003093 10031947532846003093 Yes Department of Animal Sciences, College of Agriculture and Natural Resources, Razi University, Kermanshah, Iran Maryam Darbemamieh darbemamieh@gmail.com 10031947532846003094 10031947532846003094 No Department of Plant Protection, College of Agriculture and Natural Resources, Razi University, Kermanshah, Iran