| Institution: | 1. Department of Clinical Biochemistry, School of Medicine, Babol University of Medical Sciences, Babol, Mazandaran, Iran;2. Nano Drug Delivery Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran
Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran;3. Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran;4. Department of Cell and Molecular Biology and Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran;5. Department of Biochemistry, Faculty of Biological Sciences, University of Tarbiat Modares, Tehran, Iran;6. Student Research Committee, Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran;7. Department of Nanotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran;8. Department of Chemical and Materials Engineering, The University of Alabama in Huntsville, Huntsville, Alabama;9. Immunogenetic Research Center, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran;10. Nanotechnology Research Centre, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran;11. Bioclinicum, Department of Oncology-Pathology, Karolinska Institute, Stockholm, Sweden;12. Department of Oncology, Cross Cancer Institute, The University of Alberta, Edmonton, Alberta, Canada;13. Cellular and Molecular Research Center, Yasuj University of Medical Sciences, Yasuj, Iran;14. Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran |
| Abstract: | Inhibitory immune checkpoint (ICP) molecules are important immunosuppressive factors in a tumor microenvironment (TME). They can robustly suppress T-cell-mediated antitumor immune responses leading to cancer progression. Among the checkpoint molecules, cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) is one of the critical inhibitors of anticancer T-cell responses. Besides, the expression of adenosine receptor (A2AR) on tumor-infiltrating T cells potently reduces their function. We hypothesized that concomitant silencing of these molecules in T cells might lead to enhanced antitumor responses. To examine this assumption, we purified T cells from the tumor, spleen, and local lymph nodes of CT26 colon cancer-bearing mice and suppressed the expression of A2AR and CTLA-4 using the small interfering RNA (siRNA)-loaded polyethylene glycol-chitosan-alginate (PCA) nanoparticles. The appropriate physicochemical properties of the produced nanoparticles (NPs; size of 72 nm, polydispersive index PDI] < 0.2, and zeta potential of 11 mV) resulted in their high efficiency in transfection and suppression of target gene expression. Following the silencing of checkpoint molecules, various T-cell functions, including proliferation, apoptosis, cytokine secretion, differentiation, and cytotoxicity were analyzed, ex vivo. The results showed that the generated nanoparticles had optimal physicochemical characteristics and significantly suppressed the expression of target molecules in T cells. Moreover, a concomitant blockade of A2AR and CTLA-4 in T cells could synergistically enhance antitumor responses through the downregulation of PKA, SHP2, and PP2Aα signaling pathways. Therefore, this combination therapy can be considered as a novel promising anticancer therapeutic strategy, which should be further investigated in subsequent studies. |
