dual blockade of pd-l1 and axl: a novel immunotherapeutic approach for ovarian and cervical cancer

Tumor microenvironment modulators have produced durable effects in cancer treatment. targeting immune checkpoint receptors, such as pd-l1, has demonstrated efficacy in eliciting antitumor responses. however, resistance to immune checkpoint blockers (icbs) has constrained the efficacy of these therapies. previous studies showed a link between the expression of axl receptor tyrosine kinase and resistance to icbs. therefore, designing combination treatments with synergistic mechanisms to overcome icb-based resistance is needed. in addition to antibody-based therapies, gene silencing with sirnas has recently been explored to alter the cancer environment to enhance the immune response.in this study, we targeted pd-l1 using an sirna and axl using a blocker (r428) in ovacar-3 and caski cells, ovarian and cervical cancer cell lines, respectively, in the following groups: scramble-sirna, pd-l1-sirna, scramble-sirna in conjunction with r428, pd-l1-sirna in conjunction with r428, r428 monotherapy and untreated controls. cell viability was assessed by mtt assay after 48 hours of treatment, and cisplatin sensitization was evaluated in resistant ovacar-3 cells. gene expression was analyzed by qrt-pcr, while flow cytometry quantified cd44+pd-l1+ populations, apoptosis (annexin v/pi), and cell cycle distribution.the results showed a significant decrease in cell proliferation, suppression of emt-regulating genes, reduction of stemness in cancer cells, increased apoptosis and disruption of the cell cycle in the studied cell lines.these findings suggest that simultaneous blockade of pd-l1 and axl could serve as a novel tumor-suppressive strategy, especially for cancer patients resistant to icbs.