Identification of a NACC1-Regulated Gene Signature Impli-Cated in the Features of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC), characterized by deficiency in estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor2 (HER2), is among the most lethal subtypes of breast cancer (BC). Nevertheless, the molecular determinants that contribute to its malignant phenotype such as tumor heterogeneity and therapy resistance remain elusive. In this study, we sought to identify the stemness-associated genes involved in TNBC progression. Using bioinformatics approach, we found 55-up and 9-down regulated genes in TNBC. Out of the 55 upregulated genes, a 5 gene-signature (CDK1, EZH2, CCNB1, CCNA2, and AURKA) involved in cell regeneration, was positively correlated with status of tumor hypoxia and clustered with stemness-associated genes, as recognized by Parametric Gene Set Enrichment Analysis (PGSEA). Also, enhanced infiltration of immunosuppressive cells was positively correlated with the expression of these 5 genes. Moreover, our experiments showed that depletion of the transcriptional co-factor nucleus accumbens-associated protein 1 (NAC1), which is highly expressed in TNBC, reduced the expressions of these genes. Thus, the five genes signature identified by this study warrants further exploration as a potential new biomarker of TNBC heterogeneity/stemness characterized by high hypoxia, stemness enrichment, and immune-suppressive tumor microenvironment.