Tabriz University of Medical Sciences BioImpacts 2228-5652 12 6 2022 11 05 Evaluation of poly (lactic-co-glycolic acid) nanoparticles to improve the therapeutic efficacy of paclitaxel in breast cancer 515 531 10.34172/bi.2022.23433 EN Laura Cabeza https://orcid.org/0000-0001-9369-5945 Mazen M. El-Hammadi https://orcid.org/0000-0002-3563-5159 Raul Ortiz https://orcid.org/0000-0001-8409-5235 Maria D. Cayero-Otero Julia Jiménez-López https://orcid.org/0000-0003-4659-4070 Gloria Perazzoli https://orcid.org/0000-0003-2205-749X Lucia Martin-Banderas https://orcid.org/0000-0003-1447-6125 Jose M. Baeyens https://orcid.org/0000-0001-7168-0523 Consolación Melguizo https://orcid.org/0000-0003-3990-806X Jose Prados https://orcid.org/0000-0003-4303-7746 Journal Article 10.34172/bi.2022.23433 2020 09 25 2021 02 20 Introduction: Paclitaxel (PTX) is a cornerstone in the treatment of breast cancer, the most common type of cancer in women. However, this drug has serious limitations, including lack of tissue-specificity, poor water solubility, and the development of drug resistance. The transport of PTX in a polymeric nanoformulation could overcome these limitations. Methods: In this study, PLGA-PTX nanoparticles (NPs) were assayed in breast cancer cell lines, breast cancer stem cells (CSCs) and multicellular tumor spheroids (MTSs) analyzing cell cycle, cell uptake (Nile Red-NR-) and α-tubulin expression. In addition, PLGA-PTX NPs were tested in vivo using C57BL/6 mice, including a biodistribution assay. Results: PTX-PLGA NPs induced a significant decrease in the PTX IC50 of cancer cell lines (1.31 and 3.03-fold reduction in MDA-MB-231 and E0771 cells, respectively) and CSCs. In addition, MTSs treated with PTX-PLGA exhibited a more disorganized surface and significantly higher cell death rates compared to free PTX (27.9% and 16.3% less in MTSs from MCF-7 and E0771, respectively). PTX-PLGA nanoformulation preserved PTX’s mechanism of action and increased its cell internalization. Interestingly, PTX-PLGA NPs not only reduced the tumor volume of treated mice but also increased the antineoplastic drug accumulation in their lungs, liver, and spleen. In addition, mice treated with PTX-loaded NPs showed blood parameters similar to the control mice, in contrast with free PTX. Conclusion: These results suggest that our PTX-PLGA NPs could be a suitable strategy for breast cancer therapy, improving antitumor drug efficiency and reducing systemic toxicity without altering its mechanism of action.