Understanding the causes of tumorigenesis and progression in triple-receptor negative breast cancer (TNBC) can help the design of novel and personalized therapies and prognostic assessments. Abnormal RNA modification is a recently discovered process in TNBC development. TNBC samples from The Cancer Genome Atlas database were categorized according to the expression level of NAT10, which drives acetylation of cytidine in RNA to N(4)-acetylcytidine (ac4C) and affects mRNA stability. A total of 703 differentially expressed long non-coding RNAs (lncRNAs) were found between high- and low-expressed NAT10 groups in TNBC. Twenty of these lncRNAs were significantly associated with prognosis. Two breast cancer tissues and their paired normal tissues were sequenced at the whole genome level using acetylated RNA immunoprecipitation sequencing (acRIP-seq) technology to identify acetylation features in TNBC, and 180 genes were significantly differentially ac4c acetylated in patients. We also analyzed the genome-wide lncRNA expression profile and constructed a co-expression network, containing 116 ac4C genes and 1080 lncRNAs. Three of these lncRNAs were prognostic risk lncRNAs affected by NAT10 and contained in the network. The corresponding reciprocal pairs were “LINC01614-COL3A1”, “OIP5-AS1-USP8”, and “RP5-908M14.9-TRIR”. These results indicate that RNA ac4c acetylation involves lncRNAs and affects the tumor process and prognosis of TNBC. This will aid the prediction of drug targets and drug sensitivity.

Background: Accumulating evidence indicates that PSAT1 not only reprogrammed metabolic function but also exhibits “moonlighting” functions in promoting tumor malignancy. However, the underlying molecular mechanisms of PSAT1 promoting ER-negative breast cancer cell migration need further investigation. Methods: Briefly, the PSAT1 and ITGA2 expression in cells and tissues was detected using qRT-PCR, immunofluorescence staining and western blot assay. The effect of PSAT1 and ITGA2 was verified both in vitro and in vivo. RNA-seq analysis explored a series of differently expressed genes. The regulation between SP1 and ITGA2 was investigated by ChIP analysis. Results: We reported PSAT1 was highly expressed in ER-breast cancer tissues and tumor cells and positively correlated with metastasis. Moreover, RNA-seq analysis explored a series of differently expressed genes, including ITGA2, in PSAT1 overexpressed cells. Mechanistically, PSAT1 facilitated breast cancer metastasis via the p-AKT/SP1/ITGA2 axis. We further elucidated that PSAT1 promoted the entry of SP1 into the nucleus through the upregulation of p-AKT and confirmed ITGA2 is a target of SP1. In addition, enhanced cell migration was remarkably reversed by ITGA2 depletion or p-AKT inhibitor treatment. Conclusion: This study clarified the mechanism of PSAT1 in promoting ER-negative breast cancer metastasis, which may provide mechanistic clues for attenuating breast cancer metastasis.

Background: N-acetyltransferase 10 (NAT10) mediated N4-acetylcytidine (ac4C) modification has been implicated in tumor progression; however, the precise role and underlying mechanism of NAT10 in breast cancer progression remain largely undefined. Methods: The expression and prognostic significance of NAT10 in breast cancer were evaluated using clinical tissue samples and public databases. Functional assays were performed in vitro and in vivo to assess the effects of NAT10 on tumor growth and immune evasion. Mechanistic studies, including RNA immunoprecipitation (RIP), ac4C RNA immunoprecipitation (acRIP), and co-immunoprecipitation (Co-IP), were conducted to elucidate the interaction between NAT10 and histone deacetylase 4 (HDAC4) and their roles in regulating NF-κB signaling and programmed death-ligand 1 (PD-L1) expression. Results: NAT10 expression was significantly upregulated in breast cancer and correlated with poor patient prognosis. NAT10 mediated ac4C modification enhanced the stability of HDAC4 mRNA, thereby promoting HDAC4 expression. Conversely, HDAC4 stabilized NAT10 protein through post-transcriptional deacetylation, forming a self-reinforcing regulatory loop. Elevated HDAC4 activated the NF-κB signaling pathway, resulting in increased PD-L1 transcription and enhanced immune evasion of breast cancer cells. Inhibition of the NAT10/HDAC4/NF-κB axis markedly reduced PD-L1 expression and restored antitumor immune responses. Conclusion: Our findings identify a self-reinforcing NAT10/HDAC4 signaling circuit that drives breast cancer progression and immune evasion. Targeting NAT10 represents a promising therapeutic strategy to overcome immunosuppression and improve patient outcomes in breast cancer.