Dual Blockade of PD-L1 and AXL: A Novel Immunotherapeutic Approach  for Ovarian and Cervical Cancer

Hossein  Rahavi; Ahmad  Najafi; Hossein  Asgarian-Omran; Behrouz  Aflatoonian; Mohsen  Tehrani; Ehsan Farashahi-Yazd

doi:10.18502/ijaai.v25i2.20802

Hossein Rahavi Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
Ahmad Najafi SABA Biomedicals Knowledge-Enterprise Co, Tehran, Iran
Hossein Asgarian-Omran Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
Behrouz Aflatoonian Stem Cell Biology Research Center, Yazd Reproductive Sciences Institute, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Mohsen Tehrani Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
Ehsan Farashahi-Yazd Stem Cell Biology Research Center, Yazd Reproductive Sciences Institute, Shahid Sadoughi University of Medical Sciences, Yazd, Iran

DOI: https://doi.org/10.18502/ijaai.v25i2.20802

Keywords: Axl receptor tyrosine kinase; Cervical cancer; Molecular targeted therapies; Ovarian cancer; Programmed death ligand 1; siRNA

Abstract

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.