The involvement of store-operated calcium channels (SOCCs) in tumor initiation and metastatic dissemination has been extensively studied, but how its member ORAI3 influences tumor progression is still elusive. The present study aimed to evaluate the prognostic value of ORAI3 expression and examine the correlation between ORAI3 expression and immune cell infiltration within the tumor microenvironment (TME) in human muscle-invasive bladder cancer (MIBC). We examined the expression profile of ORAI3 in MIBC using data from two databases; analyzed the correlation between ORAI3 expression and patient survival; explored cellular pathways related to ORAI3 expression by Gene Set Enrichment Analysis (GSEA); and predicted potential drugs using Connectivity Map (CMap). ORAI3 was significantly lower expressed in tumor mass compared to normal samples in MIBC, with a higher level of methylation at the promoter region in tumor than in normal tissue, indicating that ORAI3 is suppressed during cancer progression. Survival analysis showed that higher expression of ORAI3 correlated with good prognosis in MIBC. GSEA demonstrated that ORAI3 expression inversely correlated with cell differentiation, development and gene silencing, with differential expression of genes involved in epidermal and keratinocyte differentiation pathways and inflammatory responses. RNA sequencing of an ORAI3-silenced human bladder cancer cell line (T24 cells) corroborated enhancement of pro-neoplastic pathways in absence of ORAI3. Western blottingMoreover, ORAI3 facilitated the recruitment of Th17 cells and natural killer cells, whereas hampered Th2 and macrophage infiltration. Our results revealed 4 molecules with potential to be beneficial as adjuvant drugs in MIBC treatment. We concluded that high ORAI3 expression correlates with increased survival in human MIBC.
Keywords: Immune cells infiltration; Macrophage; Muscle-invasive bladder cancer; ORAI3; Store-operated calcium channel.
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