RESUMO
AIM: The acetyltransferase TIP60 is reported to be downregulated in several cancers, in particular breast cancer, but the molecular mechanisms resulting from its alteration are still unclear. MATERIALS & METHODS: In breast tumors, H3K4ac enrichment and its link with TIP60 were evaluated by chromatin immunoprecipitation-qPCR and re-chromatin immunoprecipitation techniques. To assess the biological roles of TIP60 in breast cancer, two cell lines of breast cancer, MDA-MB-231 (ER-) and MCF-7 (ER+) were transfected with shRNA specifically targeting TIP60 and injected to athymic Balb-c mice. RESULTS: We identified a potential target of TIP60, H3K4. We show that an underexpression of TIP60 could contribute to a reduction of H3K4 acetylation in breast cancer. An increase in tumor development was noted in sh-TIP60 MDA-MB-231 xenografts and a slowdown of tumor growth in sh-TIP60 MCF-7 xenografts. CONCLUSION: This is evidence that the underexpression of TIP60 observed in breast cancer can promote the tumorigenesis of ER-negative tumors.
Assuntos
Neoplasias da Mama/genética , Código das Histonas , Histonas/metabolismo , Lisina Acetiltransferase 5/metabolismo , Acetilação , Animais , Neoplasias da Mama/metabolismo , Feminino , Humanos , Lisina Acetiltransferase 5/genética , Células MCF-7 , Camundongos , Camundongos Endogâmicos BALB C , Camundongos NusRESUMO
BACKGROUND: H3K27me3 histone marks shape the inhibition of gene transcription. In prostate cancer, the deregulation of H3K27me3 marks might play a role in prostate tumor progression. METHODS: We investigated genome-wide H3K27me3 histone methylation profile using chromatin immunoprecipitation (ChIP) and 2X400K promoter microarrays to identify differentially-enriched regions in biopsy samples from prostate cancer patients. H3K27me3 marks were assessed in 34 prostate tumors: 11 with Gleason score > 7 (GS > 7), 10 with Gleason score ≤ 7 (GS ≤ 7), and 13 morphologically normal prostate samples. RESULTS: Here, H3K27me3 profiling identified an average of 386 enriched-genes on promoter regions in healthy control group versus 545 genes in GS ≤ 7 and 748 genes in GS > 7 group. We then ran a factorial discriminant analysis (FDA) and compared the enriched genes in prostate-tumor biopsies and normal biopsies using ANOVA to identify significantly differentially-enriched genes. The analysis identified ALG5, EXOSC8, CBX1, GRID2, GRIN3B, ING3, MYO1D, NPHP3-AS1, MSH6, FBXO11, SND1, SPATS2, TENM4 and TRA2A genes. These genes are possibly associated with prostate cancer. Notably, the H3K27me3 histone mark emerged as a novel regulatory mechanism in poor-prognosis prostate cancer. CONCLUSIONS: Our findings point to epigenetic mark H3K27me3 as an important event in prostate carcinogenesis and progression. The results reported here provide new molecular insights into the pathogenesis of prostate cancer.
Assuntos
Metilação de DNA , Redes Reguladoras de Genes , Histonas/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Neoplasias da Próstata/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Homólogo 5 da Proteína Cromobox , Análise Discriminante , Progressão da Doença , Epigênese Genética , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Regiões Promotoras Genéticas , Neoplasias da Próstata/genéticaRESUMO
BACKGROUND/AIM: Numerous studies have shown that breast cancer and epigenetic mechanisms have a very powerful interactive relation. The MCF7 cell line, representative of luminal subtype and the MDA-MB 231 cell line representative of mesenchymal-like subtype were treated respectively with a Histone Methyl Transferase Inhibitors (HMTi), 3-Deazaneplanocin hydrochloride (DZNep), two histone deacetylase inhibitors (HDACi), sodium butyrate (NaBu), and suberoylanilide hydroxamic acid (SAHA) for 48 h. MATERIALS AND METHODS: Chromatin immunoprecipitation (ChIP) was used to observe HDACis (SAHA and NaBu) and HMTi (DZNep) impact on histones and more specifically on H3K27me3, H3K9ac and H3K4ac marks with Q-PCR analysis of BRCA1, SRC3 and P300 genes. Furthermore, the HDACi and HMTi effects on mRNA and protein expression of BRCA1, SRC3 and P300 genes were checked. In addition, statistical analyses were used. RESULTS: In the MCF7 luminal subtype with positive ER, H3k4ac was significantly increased on BRCA1 with SAHA. On the contrary, in the MDA-MB 231 breast cancer cell line, representative of mesenchymal-like subtype with negative estrogen receptor, HDACis had no effect. Also, DZNEP decreased significantly H3K27me3 on BRCA1 in MDA-MB 231. Besides, on SRC3, a significant increase for H3K4ac was obtained in MCF7 treated with SAHA. And DZNEP had no effect in MCF7. Also, in MDA-MB 231 treated with DZNEP, H3K27me3 significantly decreased on SRC3 while H3K4ac was significantly increased in MDA-MB-231 treated with SAHA or NaBu for P300. CONCLUSION: Luminal and mesenchymal-like breast cancer subtype cell lines seemed to act differently to HDACis (SAHA and NaBu) or HMTi (DZNEP) treatments.
Assuntos
Adenosina/análogos & derivados , Antineoplásicos/farmacologia , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Epigênese Genética/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Inibidores de Histona Desacetilases/farmacologia , Adenosina/farmacologia , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Linhagem Celular Tumoral , Proteína p300 Associada a E1A/genética , Proteína p300 Associada a E1A/metabolismo , Feminino , Histonas/metabolismo , Humanos , Coativador 3 de Receptor Nuclear/genética , Coativador 3 de Receptor Nuclear/metabolismoAssuntos
Biomarcadores Tumorais/genética , Epigênese Genética , Receptores Androgênicos/genética , Neoplasias de Mama Triplo Negativas/genética , Biomarcadores Tumorais/metabolismo , Linhagem Celular Tumoral , Marcadores Genéticos , Humanos , Imuno-Histoquímica , Receptores Androgênicos/metabolismo , Transcriptoma/genéticaRESUMO
Triple negative breast cancer (TNBC) represents about 15% to 20% of all breast cancers and is typically associated with poorer outcome than other breast cancer subtypes. The heterogeneity of this breast cancer subtype and present lack of clinically established targeted therapies further complicates treatment of patients. The treatment of TNBC emphasizes enhancing health care and developing personalized medicine. To respond to this need, the researchers have turned their attention to a different approach to scientific enquiry: the era of "big biology" and the integrative study of biological systems, also called "Omics" technologies. The term omics comprises different fields of molecular studies and characterizes a global view on biological molecules such as DNA, RNA, proteins, and metabolites. Combined "omics" approach offers a major tool for the understanding of a challenging cancer model, TNBC. This review discusses the different discoveries made using omics technologies concerning the molecular mechanisms underlying TNBC phenotypic heterogeneity, and their potential transfer to clinical applications.
