Elevated TUBA1A Might Indicate the Clinical Outcomes of Patients with Gastric Cancer, Being Associated with the Infiltration of Macrophages in the Tumor Immune Microenvironment

Abstract

Background and Aims: TUBA1A belongs to the tubulin superfamily, and its role in gastric cancer (GC) remains unclear. This study assessed the expression and effect of TUBA1A in GC, as well as its association with survival and clinicopathological features. Gene set enrichment analysis (GSEA) results revealed that high TUBA1A expression was associated with multiple pathways, including those that contributed to the infiltration of macrophages in the tumor microenvironment. Since increased infiltration of macrophages can lead to oxaliplatin resistance, we analyzed the association between TUBA1A, the infiltration of macrophages to the tumor microenvironment, and the inhibitory concentration 50% (IC50) of oxaliplatin. In addition, we analyzed the possible epigenetic regulation mechanism.

Methods: A total of 1,881 samples, including 1,618 patients with GC and 263 normal samples, were examined. The associations between clinicopathological features and TUBA1A were assessed by chi-square test, survival was assessed by Kaplan-Meier analysis, and gene set enrichment analysis (GSEA) was performed to explore the potential mechanisms. The associations between TUBA1A and immune infiltration of M0-, M1-, and M2- polarized macrophages were examined by applying deconvolution’s quantification and Pearson’s correlation analysis. The association of TUBA1A with the IC50 of oxaliplatin was analyzed by Pearson correlation test. The mechanisms of TUBA1A dysregulation were studied by analyzing methylation data. A single-cell TUBA1A mRNA expression map of the stomach was drawn from the analysis of stomach single-cell RNA sequencing data that included more than 13,000 single cells of 17 stomach cell types. Results: TUBA1A expression was elevated in GC (p<0.01) and indicated poorer overall survival (p<0.001), first progression survival (p<0.001), and post-progression survival (p<0.01). High TUBA1A expression was significantly correlated with more aggressive clinicopathological features of GC patients (p<0.001). Elevated TUBA1A contributes to the infiltration of macrophages to the tumor microenvironment (p<0.001) and increased the IC50 of oxaliplatin in vitro (p<0.05), while hypomethylation was shown to contribute to the upregulation of TUBA1A (p<0.05).

Conclusions: TUBA1A might be a potential prognostic marker and therapeutic target in GC. TUBA1A is significantly associated with the infiltration of M2-polarized macrophages in GC, and the IC50 of oxaliplatin. Hypomethylation contributes to the upregulation of TUBA1A in GC.