The Anti-Tumor and Immunomodulatory Effects of PLGA-Based Docetaxel Nanoparticles in Lung Cancer: The Potential Involvement of Necroptotic Cell Death through Reactive Oxygen Species and Calcium Build-Up.

Taxanes, microtubule stabilizing agents, are extensively used in the treatment of non-small cell lung cancer (NSCLC). However, their clinical effectiveness remains restricted owing to significant adverse effects and drug resistance. Nanotechnology may guide chemotherapeutic drugs directly and selectively to malignant cells, improving their therapeutic efficiency. In the present study, we synthesized polylactic-co-glycolic acid (PLGA) based nanoparticles encapsulating docetaxel and evaluated their efficacy in non-small cell lung carcinoma (A549) cells and primary immune cells derived from humans. Docetaxel-PLGA nanoparticles (PLGA-Dtx) were synthesized and characterized using distinct methods. Moreover, the cytotoxicity of free docetaxel (Dtx) and Dtx-conjugated nanoparticles (PLGA-Dtx) was studied in A549 cells and peripheral blood mononuclear cells derived from humans. Furthermore, annexin V-FITC/PI staining was used to assess the mode of cell death. Additionally, human peripheral blood mononuclear cells (PBMCs) were used for assessing the associated immune response and cytokine profile following PLGA-Dtx treatment. Spherical PLGA-Dtx nanoparticles with a 150 ± 10 nm diameter and 70% encapsulation efficiency (EE) were synthesized. The MTT assay showed that the IC of PLGA-Dtx nanoparticles was significantly lower than free docetaxel in A549 cells. Cytotoxicity data also revealed the selective nature of PLGA-Dtx with no significant effects in normal human bronchial epithelial cells (BEAS-2B) and PBMCs derived from healthy donors. Interestingly, PLGA-Dtx exerted an improved effect and tempted both apoptosis and necroptosis, as evidenced by annexin V and propidium iodide-positive cells. Further, PLGA-Dtx-exposed A549 cells showed increased Cas-3, Cas-9, RIP-1, and RIP-3, indicating apoptosis and necroptosis. An increased pro-inflammatory response manifested from the enhancement of IFN-γ and TNF-α in PLGA-Dtx-exposed PBMCs, posed by the occurrence of necroptosis and the immune stimulatory effect of PLGA-Dtx. In conclusion, PLGA-Dtx has a selective anticancer potential and better immunostimulatory potential. Therefore, PLGA-Dtx may be useful for the treatment of non-small cell lung carcinoma.