EZH2 immunoexpression in pleomorphic adenoma and adenoid cystic carcinoma and clinicopathological features

Abstract The aim of this study was to evaluate the expression of the EZH2 protein and describe the clinical and microscopic characteristics of adenoid cystic carcinoma (ACC) and pleomorphic adenoma (PA). The study included 16 ACC cases and 12 PA. All ACC and PA cases were positive for EZH2 and the ACC samples showed significantly higher EZH2 expression. The clinical and microscopic covariates were described in relation to EZH2 staining in ACC samples. The highest mean values of EZH2 were observed in cases with local metastasis, recurrence, perineural invasion, and predominantly cribriform growth pattern without solid areas. EZH2 is a potential marker of malignancy.

Effects of enhancer of zeste homolog 2 and mucin 1 expressions on treatment response in breast cancer

SUMMARY OBJECTIVE: Breast cancer is the most common malignancy in women. In the treatment of these patients, pathological complete response is defined as the absence of invasive cancer in breast or lymph node tissue after the completion of neoadjuvant chemotherapy. In this study, we aimed to investigate the relationship of enhancer of zeste homolog 2 and mucin 1 expressions with pathological complete response in patients with breast cancer receiving neoadjuvant chemotherapy. METHODS: A total of 151 patients were included in the study. Enhancer of zeste homolog 2 and mucin 1 expressions were evaluated in the biopsy materials pre-neoadjuvant chemotherapy and post-neoadjuvant chemotherapy surgical material, and their relationship with pathological complete response was investigated. RESULTS: The pathological complete response rates were significantly higher among the hormone receptor-negative patients, those with a high Ki-67 score, and patients with HER2-positive. Higher pathological complete response rates were obtained from patients with enhancer of zeste homolog 2 expression positivity pre-neoadjuvant chemotherapy. In addition, after neoadjuvant chemotherapy, enhancer of zeste homolog 2 expression was found to be completely negative in materials with pathological complete response; that is, in breast tissues considered to be tumor-free. While there was no significant relationship between mucin 1 expression and pathological complete response pre-neoadjuvant chemotherapy, mucin 1 expression was determined to significantly differ between the tissues with and without pathological complete response among the surgical materials examined. CONCLUSION: In our study investigating the relationship between enhancer of zeste homolog 2 and mucin 1 expression and pathological complete response in patients who received neoadjuvant chemotherapy, we found that enhancer of zeste homolog 2 expression could be used as a predictive marker for pathological complete response. However, mucin 1 expression was not associated with pathological complete response.

Dietary polyphenols and their relationship to the modulation of non-communicable chronic diseases and epigenetic mechanisms: A mini-review.

Chronic Non-Communicable Diseases (NCDs) have been considered a global health problem, characterized as diseases of multiple factors, which are developed throughout life, and regardless of genetics as a risk factor of important relevance, the increase in mortality attributed to the disease to environmental factors and the lifestyle one leads. Although the reactive species (ROS/RNS) are necessary for several physiological processes, their overproduction is directly related to the pathogenesis and aggravation of NCDs. In contrast, dietary polyphenols have been widely associated with minimizing oxidative stress and inflammation. In addition to their antioxidant power, polyphenols have also drawn attention for being able to modulate both gene expression and modify epigenetic alterations, suggesting an essential involvement in the prevention and/or development of some pathologies. Therefore, this review briefly explained the mechanisms in the development of some NCDs, followed by a summary of some evidence related to the interaction of polyphenols in oxidative stress, as well as the modulation of epigenetic mechanisms involved in the management of NCDs.

Avaliação da expressão da proteína EZH2 em carcinoma adenoide cístico e adenoma pleomórfico / EZH2 immunoexpression in adenoid cystic carcinoma and pleomorphic adenoma

As neoplasias de glândulas salivares apresentam comportamentos diferenciados, que não seguem os padrões clássicos das neoplasias benignas e malignas. A raridade de algumas destas lesões dificulta ainda mais o entendimento dos mecanismos envolvidos na etiopatogenia. Marcadores moleculares como a proteína EZH2 têm sido utilizados na investigação de alterações epigenéticas em diferentes neoplasias, auxiliando na definição do diagnóstico e prognóstico das lesões. O objetivo do presente trabalho é avaliar a expressão da proteína EZH2 e descrever as características clínicas e microscópicas de amostras de carcinoma adenoide cístico (CAC) e adenoma pleomórfico (AP) com ênfase na importância da definição da malignidade da lesão. A análise dos cortes microscópicos corados em Hematoxilina e Eosina dos casos de Adenoma pleomórfico mostraram células epiteliais e mioepiteliais glandulares dispostas em lençóis e estruturas ductiformes em meio a estroma variável. Os casos de Carcinoma adenoide cístico mostraram três padrões distintos de crescimento incluindo formações tubulares, cribriformes e sólidas. Todos os casos de AP e CAC foram positivos para reação imuno-histoquímica para EZH2. As amostras de CAC apresentaram expressão de EZH2 significativamente maior comparado ao AP. As covariáveis metástase em linfonodos, recorrência, padrão histológico, presença de áreas sólidas e invasão perineural foram descritas em relação à marcação de EZH2 em amostras de CAC. Dessa forma, os resultados do estudo melhoram o entendimento das características clínicas e histológicas do CAC, assim como sobre o comportamento das lesões. Além disso, a análise mostra que o EZH2 é um potencial marcador de malignidade e ressalta a importância da validação de marcadores moleculares de alterações epigenéticas.

Salivary gland neoplasms present different behaviors, which do not follow the classic patterns of benign and malignant neoplasms. The rarity of some of these lesions makes it even more difficult to understand the mechanisms involved in the etiopathogenesis. Molecular markers such as the EZH2 protein have been used to investigate epigenetic changes in different neoplasms, helping to define the diagnosis and prognosis of the lesions. The aim of the study was to evaluate the expression of the EZH2 protein and to describe the clinical and microscopic characteristics of adenoid cystic carcinoma (ACC) and pleomorphic adenoma (PA) which emphasizes the importance of defining the malignancy of the neoplasm. Histopathological analysis of PA cases showed myoepithelial and glandular epithelial cells arranged as duct-like structures and sheets intermingled in the variable stroma and ACC cases showed the three growth patterns, tubular, cribriform and solid forms. All ACC and PA cases were positive for EZH2, with diffuse nuclear staining in neoplastic cells. The ACC samples showed significantly higher EZH2 expression compared to the PA. The covariables nodal metastasis, recurrence, growth pattern, presence of solid areas and perineural invasion have been described in relation to EZH2 staining in ACC samples. The results of the study improve the understanding of the clinical and histological characteristics of ACC, as well as on the behavior of lesions. In addition, the analysis showed that EZH2 is a potential marker of malignancy and highlights the importance of validating molecular markers of epigenetic alterations.

Effect of lincRNA PVT1 associated with Enhancer of Zeste homolog 2 (EZH2) and with androgen receptor (AR) on the large-scale gene expression in LNCaP prostate cancer cells

O lincRNA PVT1 (Plasmacytoma Variant Translocation 1) é um RNA longo não codificador de proteínas (ncRNA) descrito como um oncogene sendo superexpresso em vários tipos de cânceres. LincRNA PVT1 está localizado na região genômica 8q24, também conhecida como 'gene desert'. O nível de expressão do lincRNA PVT1 está associado ao aumento do risco de câncer de próstata (PCa) e está correlacionado com os níveis de expressão do receptor de andrógeno (AR). No entanto, o mecanismo do envolvimento do lincRNA PVT1 com o AR no desenvolvimento de câncer de próstata ainda não está bem esclarecido. Aqui, nós testamos a hipótese que a formação do complexo AR-EZH2-PVT1 participa na regulação da expressão gênica em câncer de próstata, nas células LNCaP. A imunoprecipitação de ribonucleoproteínas seguida de PCR quantitativo (RIP-qPCR) revelou que o lincRNA PVT1 está associado fisicamente ao AR (12% do input) e à metiltransferase EZH2, proteína componente do complexo repressor Polycomb 2 (36% do input) sob condições suplementadas com andrógeno (+R1881). O lincRNA PVT1 também está associado fisicamente ao AR (10% de input) e à EZH2 (42% de input) em condições de privação de andrógeno (-R1881). Assim, a associação física entre lincRNA PVT1, AR e EZH2 é independente do hormônio andrógeno. Usando uma abordagem de estudo em larga-escala de perda e ganho de função, nossos resultados mostraram que o silenciamento do lincRNA PVT1 em células LNCaP na presença de andrógeno restaura a expressão parcialmente, totalmente ou causa superexpressão de 160 genes que tiveram a expressão inibida por andrógeno. Entre esses genes, destacamos genes envolvidos na regulação da diferenciação celular, em componentes da junção célula-célula, na inibição da migração e invasão celular e no desencadeamento da via apoptótica. Imunoprecipitação da cromatina seguida de PCR quantitativo (ChIP-qPCR), em cultura de células LNCaP suplementada com andrógeno sob silenciamento do lincRNA PVT1, mostrou aumento significativo na ocupação pela marca de histona ativadora H3K27Ac do promotor do gene NOV, um dos genes que tiveram sua expressão aumentada com o silenciamento de PVT1. O ChIP-qPCR também mostrou, após o silenciamento do lincRNA PVT1, um aumento significativo da marca H3K27me3 na região enhancer do gene NOV, uma característica de enhancers poised (prontos para ativação). Em conclusão, nós fornecemos a primeira evidência experimental para um mecanismo de ação do oncogene lincRNA PVT1 em células de câncer de próstata e demonstramos que sua ação inibidora da expressão afeta genes alvo que facilitam a proliferação e migração de células do câncer de próstata, sugerindo que o lincRNA PVT1 é um novo agente no complexo mecanismo de repressão transcricional envolvendo um RNA silenciador, o receptor de andrógeno (AR) e o potenciador de Zeste homólogo 2 (EZH2) no remodelamento da cromatina em células LNCaP

Long non-coding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) is an oncogene known to be overexpressed in various types of cancer. PVT1 lincRNA is located in the wellknown cancer-related genomic region 8q24, also known as 'gene desert. PVT1 lincRNA level of expression is associated with increased prostate cancer (PCa) risk and is correlated with androgen receptor (AR) expression levels. However, the mechanism of PVT1 and AR involvement in the development of prostate cancer is still unclear. Here, we tested the hypothesis that formation of the complex AR-EZH2-PVT1 participates in the regulation of gene expression in prostate cancer, in LNCaP cells. Ribonucleoprotein immunoprecipitation followed by quantitative PCR (RIP-qPCR) revealed that PVT1 lincRNA binds both the AR (12 % of PVT1 input) and the methyltransferase EZH2 from the Polycomb repressive complex 2 (36 % of input) under androgen-supplemented conditions (+R1881). PVT1 also binds both AR (10 % of input) and EZH2 (42 % of input) under androgen-deprived conditions (-R1881). Thus, PVT1 binding to AR and EZH2 is independent of the androgen hormone. Using a large-scale loss and gain of function approach, our results show that PVT1 knockdown (KD) in LNCaP in the presence of androgen restores the expression partially, fully or causes overexpression of 160 genes that are inhibited by androgen. Among these genes, we highlight genes involved in regulation of cell differentiation, in components of cell-cell junction, in inhibition of cell migration and invasion and in triggering of the apoptotic pathway. Chromatin immunoprecipitation followed by quantitative PCR (ChIP-qPCR) with LNCaP cells in androgen-supplemented cultures under PVT1 lincRNA knockdown showed a significant increase in occupancy by the histone activation mark H3K27Ac of the promoter region of the NOV gene, one of the genes that had an increased expression upon PVT1 silencing. ChIPqPCR also showed a significant increase upon PVT1 lincRNA silencing of the H3K27me3 histone mark in the enhancer region of the NOV gene, a distinct feature of poised enhancers. In conclusion, we provide first experimental evidence for a mechanism of action of PVT1 lincRNA oncogene in prostate cancer cells, and show that its inhibitory action affects targetgenes that facilitate proliferation and migration of prostate cancer cells, thus suggesting PVT1 lincRNA as a novel lncRNA player in the complex mechanism of transcriptional repression involving a silencer RNA, the androgen receptor (AR) and the Enhancer of zeste homolog 2 (EZH2) in chromatin remodeling in LNCaP cells