AICAR-loaded and panitumumab conjugated nanoparticles downregulate the expression of PD-L1 and enhance antitumor responses against ovarian cancer through the AMPK/STAT3 axis

Purpose: In ovarian cancer, the AMP-activated protein kinase (AMPK) agonist 5-amino-4-imidazolecarboxamide ribonucleoside (AICAR) exhibits promising antitumor activity; however, its inadequate solubility in water, low half-life, and adverse effects pose major hurdles for its application in cancer treatment. This research aims to develop AICAR-loaded and anti-EGFR monoclonal antibody (panitumumab; Pmab) conjugated nanoparticle (NP) for the treatment of ovarian cancer. Methods: Pmab-conjugated AICAR-poly(lactic-co-glycolic acid) (PLGA)-NP (Pmab-AICAR-PLGA-NP) was prepared using double emulsion solvent evaporation method followed by EDC-NHS coupling reaction. Characterization of nanoparticle along with immunoreactivity and cellular uptake study was performed. In addition, the cytotoxic effect of the NP on SKOV3 ovarian cancer cells and its underlying mechanism was investigated using various techniques. Results: In this study, we observed that Pmab-AICAR-PLGA-NP yielded the desired sustained release profile and enhanced NP internalization into SKOV3 cells. Pmab-AICAR-PLGA-NP induced AMPK-dependent apoptosis of SKOV3 cells significantly higher than AICAR-PLGA-NP. Furthermore, Pmab-AICAR-PLGA-NP altered the mitochondrial membrane potential of SKOV3 cells, triggered cleavage of caspases and poly (ADP-ribose) polymerase (leading to cell death), and suppressed STAT3 phosphorylation and expression of PD-L1. Conclusion: Our formulation substantially increased the cytotoxic effects of AICAR on SKOV3 cells by modulating AMPK/STAT3 signaling. Thus, Pmab-AICAR-PLGA-NP can serve as a modular platform for utilizing AICAR for chemotherapy of ovarian cancer.