Silver nanoparticles (AgNPs) exhibit unique physicochemical properties, making these nanomaterials attractive for various medical applications. Among them, AgNPs have shown great potential in the treatment of cancer by inducing apoptosis in cancer cells, inhibiting tumor growth, and enhancing the efficacy of conventional cancer treatments such as chemotherapy and radiation therapy. Despite the promising therapeutical advantage of AgNPs, there are several challenges that need to be addressed. One of the most important is AgNPs' toxicity, which in case of treatment might be extended to non-cancerous cells and tissues. In our study, we therefore investigated the effects of spherical AgNPs with the silver core size of 10, 30, and 45 nm coated with polyacrylic acid (PAA-AgNPs) in an in vitro model using cancer (A549) and non-cancer (HEL299) cells. We estimated the impact of these nanoparticles on cell viability, cell proliferation, and cell actin cytoskeleton remodeling. Moreover, changes in the expression of TNFA, IL-10, FN1, and SOD1 mRNA induced by PAA-AgNPs were determined. Our results suggest that the smallest (10 nm) PAA-AgNPs are the most effective in apoptosis induction, however, they are also the most toxic from the three AgNPs types to both, cancer and non-cancer cells, while bigger (30 and 45 nm) PAA-AgNPs showed fewer undesirable effects in these pulmonary cells.