Amorphous silica nanoparticles exhibit antitumor activity in triple‐negative breast cancer cells

Triple‐negative breast cancer (TNBC) is an aggressive subtype of breast cancer that is mainly treated with cytotoxic chemotherapy. However, this treatment is not always effective, and an important percentage of patients develop recurrence. Nanomaterials are emerging as alternative treatment options for various diseases, including cancer. This work reports the synthesis, characterization, antitumor activity evaluation, and sub‐acute toxicity studies of two formulations based on amorphous silica nanoparticles (SiNPs). They are functionalized with 3‐aminopropyltriethoxisilane (Si@NH2) and folic acid (FA; Si@FA). The results show that SiNPs reduce the viability and migration of TNBC MDA‐MB‐231 and 4T1 cell lines and Si@FA do not affect the growth of the mammary nonmalignant HC11 cells. In addition, Si@FA induces reactive oxygen species (ROS) generation and displays antiproliferative and subsequently proapoptotic effects in MDA‐MB‐231 cells. Moreover, none of the SiNPs cause signs of sub‐acute toxicity in mice when administered at 30 mg/kg over a month. In conclusion, these nanosystems display intrinsic antitumor activity without causing toxic in vivo effects, being a promising therapeutic alternative for TNBC.