5-Aza-2’-deoxycytidine induces a greater inflammatory change, at the molecular levels, in normoxic than hypoxic tumor microenvironment

• Published in: Molecular biology reports Vol. 48; no. 2; pp. 1161 - 1169
• Main Authors: Salviano Soares de Amorim, Ísis, Rodrigues, Juliana Alves, Nicolau, Pedro, König, Sandra, Panis, Carolina, de Souza da Fonseca, Adenilson, Mencalha, Andre Luiz
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-02-2021; Springer Nature B.V
• Subjects: Acetylation - drug effects; Animal Anatomy; Animal Biochemistry; Biomedical and Life Sciences; Breast cancer; Carcinogenesis; Cell Line, Tumor; Decitabine - pharmacology; Deoxyribonucleic acid; DNA; DNA methylation; DNA Methylation - drug effects; DNA methyltransferase; DNA microarrays; DNA Modification Methylases - antagonists & inhibitors; DNA Modification Methylases - genetics; Enzyme Inhibitors - pharmacology; Epigenesis, Genetic - genetics; Epigenetics; Gene expression; Gene silencing; Histology; Humans; Hypoxia; IL-1β; Immunocytochemistry; Inflammation; Inflammation - chemically induced; Inflammation - genetics; Inflammation - pathology; Interleukin 1; Life Sciences; Localization; Morphology; NF-κB protein; Original Article; Promoter Regions, Genetic - drug effects; Promoter Regions, Genetic - genetics; Transcription Factor RelA - genetics; Transcriptomes; Tumor cells; Tumor Hypoxia - drug effects; Tumor microenvironment; Tumor Microenvironment - drug effects; Tumor Microenvironment - genetics; Transcritome; Normoxia; Hypoxia; Inflammation; 5-Aza-2’-deoxycytidine
• ISSN: 0301-4851; 1573-4978
• DOI: 10.1007/s11033-020-05931-4

Hypoxia is associated with tumor aggressiveness and poor prognosis, including breast cancer. Low oxygen levels induces global genomic hypomethylation and hypermethylation of specific loci in tumor cells. DNA methylation is a reversible epigenetic modification, usually associated with gene silencing, contributing to carcinogenesis and tumor progression. Since the effects of DNA methyltransferase inhibitor are context-dependent and as there is little data comparing their molecular effects in normoxic and hypoxic microenvironments in breast cancer, this study aimed to understand the gene expression profiles and molecular effects in response to treatment with DNA methyltransferase inhibitor in normoxia and hypoxia, using the breast cancer model. For this, a cDNA microarray was used to analyze the changes in the transcriptome upon treatment with DNA methyltransferase inhibitor (5-Aza-2’-deoxycytidine: 5-Aza-2’-dC), in normoxia and hypoxia. Furthermore, immunocytochemistry was performed to investigate the effect of 5-Aza-2’-dC on NF-κB/p65 inflammation regulator subcellular localization and expression, in normoxia and hypoxia conditions. We observed that proinflammatory pathways were upregulated by treatment with 5-Aza-2’-dC, in both conditions. However, treatment with 5-Aza-2’-dC in normoxia showed a greater amount of overexpressed proinflammatory pathways than 5-Aza-2’-dC in hypoxia. In this sense, we observed that the NF-κB expression increased only upon 5-Aza-2’-dC in normoxia. Moreover, nuclear staining for NF-κB and NF-κB target genes upregulation,
IL1A
and
IL1B
, were also observed after 5-Aza-2’-dC in normoxia. Our results suggest that 5-Aza-2’-dC induces a greater inflammatory change, at the molecular levels, in normoxic than hypoxic tumor microenvironment. These data may support further studies and expand the understanding of the DNA methyltransferase inhibitor effects in different tumor contexts.