Inhibition of colorectal cancer targets IL-6, CTLA-4, & B7-2 by Tislelizumab: molecular docking, dynamics, & STRING protein-protein network analysis

As a DNA mismatch repair deficit (dMMR) anticancer medication, and a humanized monoclonal antibody (hmAb), Tislelizumab has attracted significant interest in recent years. The programmed cell death protein-1 (PD-1) and its ligands (PD-L1/CD274/B7-H1 and PDL2/CD273) may bind to each other with great affinity. This binding prevents activated T-cells from continuing to proliferate, produce cytokines, and engage in cytotoxic action. The B7:PD-1 inhibitory immunological checkpoint receptor binds to the B7-2(CD86) B-lymphocyte activation antigen. This paper presents Tislelizumab's molecular docking and dynamics simulations with the receptor B7-2(CD86) and its downstream signaling proteins CTLA-4 and IL-6. When docked to B cell stimulatory factor-2 soluble IL-6 receptor alpha (sIL6Ra/CD126), Tislelizumab had a strong binding affinity of 329 kcal/mol and provided an excellent quality model with an LGscore of 4.54. The type I membrane protein B7-2(CD86), a member of the immunoglobulin superfamily, responded to docking with an affinity of −332.35 kcal/mol and LGscore of 2.54. Docking to the immune checkpoint protein receptor cytotoxic T-lymphocyte-associated protein-4 (CTLA-4/CD152) had a binding affinity of −305.91 kcal/mol, facilitating immunological control and cellular dissociation. Tislelizumab and these target proteins exhibited persistent and advantageous interactions in molecular dynamics studies. The STRING functional protein-protein network analysis supported our in silico docking and dynamic simulation results. This analysis also included comparisons of the binding modes of mAbs to protein receptors involved in the cancer hallmark mechanism(s), demonstrating that IL-6, B7-2, and CTLA-4 act and are inhibited in group-mode. Functional enrichment analysis and molecular modelling supported the relationship between the hallmarks of the tumor microenvironment that link inflammation to immunity. Tislelizumab may therefore be able to prevent these three proteins from acting. These findings may also shine light on Dostarlimab's mode of action, which in 2022 achieved ground-breaking success in a clinical study for colorectal cancer.