SARS-CoV-2-related IFITM3 in immune dysfunction and tumor microenvironment: An integrative analysis in pan-cancers

Multi-omics analyses of tumor-associated immune-infiltrating cells with the novel immune checkpoint protein tyrosine phosphatase 1B (PTP1B) in extracellular matrix of brain-lower-grade-glioma (LGG) and uveal-melanoma (UVM)

Immune checkpoint inhibitors represented by PD-1 have greatly changed the way cancer is treated. In addition to PD-1, new immune checkpoints are constantly excavated to better treat cancer. Recently, protein tyrosine phosphatase 1B (PTP1B) was identified as a new immune checkpoint and played a critical role in the treatment of tumors by inhibiting the proliferation and cytotoxicity of T cells induced by tumor antigen. To explore the targeting role of PTP1B in precision tumor therapy, we deeply analyzed the expression and prognosis of PTP1B in all tumors. Survival analysis results indicated that PTP1B was highly expressed in most tumor tissues and indicated poor prognosis in acute-myeloid-leukemia (LAML), brain-lower-grade-glioma (LGG), kidney-renal clear-cell-carcinoma (KIRC) and uveal-melanoma (UVM). The methylation status of PTP1B in these four tumors exhibited hypomethylation and mutation landscape showed that PTP1B had its specific characteristics in genomic instability and heterogeneity. The homologous recombination deficiency (HRD) and loss of heterozygosity (LOH) were positive related to PTP1B expression in liver-hepatocellular-carcinoma (LIHC) and kidney-chromophobe (KICH), while the immunescore and immune infiltration displayed a significant positive correlation with PTP1B expression in LGG and UVM. Drug sensitivity tests showed that the PTP1B inhibitor MSI-1436 had a sensitivity effect suppressing tumor cell viability and suggested it enhanced the efficacy of PD-1 inhibitors in cancers.

Identification of potential modulators of IFITM3 by in-silico modeling and virtual screening

IFITM3 is a transmembrane protein that confers innate immunity. It has been established to restrict entry of multiple viruses. Overexpression of IFITM3 has been shown to be associated with multiple cancers, implying IFITM3 to be good therapeutic target. The regulation of IFITM3 activity is mediated by multiple post-translational modifications (PTM). In this study, we have modelled the structure of IFITM3, consistent with experimental predictions on its membrane topology. MD simulation in membrane-aqueous environment revealed the stability of the model. Ligand binding sites on the IFITM3 surface were predicted and it was observed that the best site includes important residues involved in PTM and has good druggable score. Molecular docking was performed using FDA approved ligands and natural ligands from Super Natural II database. The ligands were re-ranked by calculating binding free energy. Select docking complexes were simulated again to substantiate the binding between ligand and IFITM3. We observed that known drugs like Eluxadoline and natural products like SN00224572 and Parishin A have good binding affinity against IFITM3. These ligands form persistent interactions with key lysine residues (Lys83, Lys104) and hence can potentially alter the activity of IFITM3. The results of this computational study can provide a starting point for experimental investigations on IFITM3 modulators.