PCMT1 confirmed as a pan-cancer immune biomarker and a contributor to breast cancer metastasis.

Abstract

Protein L-isoaspartyl (D-aspartyl) methyltransferase (PIMT, gene name PCMT1) is an enzyme that repairs proteins with altered aspartate residues by methylation, restoring their normal structure and function. This study conducted a comprehensive analysis of PCMT1 in pan-cancer. The Cancer Genome Atlas, Human Protein Atlas website, and the Genotype-Tissue Expression were utilized in analysis of PCMT1 expression. We examined the association between PCMT1 expression and various factors, including gene modifications, DNA methylation, immune cell infiltration, immunological checkpoints, drug susceptibility, tumor mutation burden (TMB), and microsatellite instability (MSI). Enrichment analyses determined the potential biological roles and pathways involving PCMT1. Our focus then shifted to the role of PCMT1 in breast invasive carcinoma (BRCA). We found that PCMT1 expression was aberrant in many tumors and significantly influenced the prognosis across several cancer types. Gene alterations in PCMT1 predominantly involved deep deletions and amplifications. A negative correlation was observed between DNA methylation and PCMT1 expression across all studied cancer types except thyroid carcinoma PCMT1 exhibited positive correlations with common lymphoid progenitor and CD4(+) T helper 2 cells, whereas it was inversely correlated with central and effector memory T cells, memory CD8(+) T cells, and CD4(+) T helper 1 cells. In many cancer types, PCMT1 expression closely correlated with immunological checkpoint inhibitors, TMB, and MSI. It was also significantly linked to pathways involved in epithelial-mesenchymal transition (EMT), highlighting its role in cancer metastasis. PCMT1 emerged as a significant predictor of breast cancer progression. In vitro experiments demonstrated that reducing PCMT1 expression decreased BRCA cell migration and invasiveness. Additionally, animal studies confirmed that inhibition of PCMT1 slowed tumor growth.