A Assinatura Epigenética na Radio-resistência do Carcinoma do Esófago

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A Assinatura Epigenética na Radio-resistência do Carcinoma do Esófago

Segunda, 18.01.2021

Investigadores do Grupo de Epigénetica e Biologia do Cancro e do Grupo de Física Médica, Radiobiologia e Protecção Radiológica do Centro de Investigação do IPO do Porto, publicaram recentemente na revista internacional Cell Death & Disease um trabalho desenvolvido no âmbito do Projecto ESTIMA (NORTE-01-0145-FEDER-000027) intitulado: “JmjC-KDMs KMD3A and KDM6B modulate radioresistance under hypoxic conditions in esophageal squamous cell carcinoma. Neste trabalho, foi evidenciado o papel das enzimas desmetilases de histonas (KDMs), em particular a KDM3A, na radio-resistência de células de carcinoma espinocelular do esófago, sob condições de hipóxia. A utilização de inibidores da atividade das KDMs em concomitância com o tratamento radioterápico leva a uma radio-sensibilização significativa deste tipo de tumores, in vitro e in vivo, atuando nas principais vias de reparação de danos de cadeia dupla na molécula de DNA, nomeadamente, na recombinação homóloga e na junção de extremidades não homóloga. A aplicação da técnica de CRISPR/cas9 KDM3A-knockdown, induziu a diminuição da dimetilação da lisina 9 da histona 3 (H3K9me2), principal alvo da atividade da KDM3A, condicionando a resposta à radioterapia da linha celular Kyse-410 sob condições de hipóxia. Globalmente, os resultados obtidos demonstram que a hipóxia induz sobre-expressão de KDM3A, conferindo resistência destes tumores à radioterapia.

 

Autores e Afiliações:

Catarina Macedo-Silva - Cancer Biology & Epigenetics Group – Research Center, Portuguese Oncology Institute of Porto, Portugal, (CI-IPOP).

Vera Miranda-Gonçalves - Cancer Biology & Epigenetics Group – Research Center, Portuguese Oncology Institute of Porto, Portugal, (CI-IPOP).

Ana Lameirinhas - Cancer Biology & Epigenetics Group – Research Center, Portuguese Oncology Institute of Porto, Portugal, (CI-IPOP).

Joana Lencart - Medical Physics, Radiobiology and Radiation Protection Group - Research Center, Portuguese Oncology Institute of Porto, Portugal, (CI-IPOP).

Alexandre Pereira - Medical Physics, Radiobiology and Radiation Protection Group - Research Center, Portuguese Oncology Institute of Porto, Portugal, (CI-IPOP).

João Lobo - Cancer Biology & Epigenetics Group – Research Center and Department of Pathology, Portuguese Oncology Institute of Porto, Portugal, (CI-IPOP); Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar – University of Porto (ICBAS-UP), Porto, Portugal.

Rita Guimarães - Department of Pathology, Portuguese Oncology Institute of Porto, Portugal, (CI-IPOP).

Ana Teresa Martins - Department of Pathology, Portuguese Oncology Institute of Porto, Portugal, (CI-IPOP).

Rui Henrique - Cancer Biology & Epigenetics Group – Research Center and Department of Pathology, Portuguese Oncology Institute of Porto, Portugal, (CI-IPOP); Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar – University of Porto (ICBAS-UP), Porto, Portugal.

Isabel Bravo - Medical Physics, Radiobiology and Radiation Protection Group - Research Center, Portuguese Oncology Institute of Porto, Portugal, (CI-IPOP).

Carmen Jerónimo - Cancer Biology & Epigenetics Group – Research Center, Portuguese Oncology Institute of Porto, Portugal, (CI-IPOP); Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar – University of Porto (ICBAS-UP), Porto, Portugal.

 

Abstract:

Esophageal squamous cell carcinoma (ESCC), the most frequent esophageal cancer (EC) subtype, entails dismal prognosis. Hypoxia, a common feature of advanced ESCC, is involved in resistance to radiotherapy (RT). RT response in hypoxia might be modulated through epigenetic mechanisms, constituting novel targets to improve patient outcome. Post-translational methylation in histone can be partially modulated by histone lysine demethylases (KDMs), which specifically removes methyl groups in certain lysine residues. KDMs deregulation was associated with tumor aggressiveness and therapy failure. Thus, we sought to unveil the role of Jumonji C domain histone lysine demethylases (JmjC-KDMs) in ESCC radioresistance acquisition. The effectiveness of RT upon ESCC cells under hypoxic conditions was assessed by colony formation assay. KDM3A/KDM6B expression, and respective H3K9me2 and H3K27me3 target marks, were evaluated by RT-qPCR, Western blot, and immunofluorescence. Effect of JmjC-KDM inhibitor IOX1, as well as KDM3Aknockdown, in in vitro functional cell behavior and RT response was assessed in ESCC under hypoxic conditions. In vivo effect of combined IOX1 and ionizing radiation treatment was evaluated in ESCC cells using CAM assay. KDM3A, KDM6B, HIF-1α, and CAIX immunoexpression was assessed in primary ESCC and normal esophagus. Herein, we found that hypoxia promoted ESCC radioresistance through increased KDM3A/KDM6B expression, enhancing cell survival and migration and decreasing DNA damage and apoptosis, in vitro. Exposure to IOX1 reverted these features, increasing ESCC radiosensitivity and decreasing ESCC microtumors size, in vivo. KDM3A was upregulated in ESCC tissues compared to the normal esophagus, associating and colocalizing with hypoxic markers (HIF-1α and CAIX). Therefore, KDM3A upregulation in ESCC cell lines and primary tumors associated with hypoxia, playing a critical role in EC aggressiveness and radioresistance. KDM3A targeting, concomitant with conventional RT, constitutes a promising strategy to improve ESCC patients’ survival.

 

Revista: Cell Death & Disease – Nature

 

Link: https://www.nature.com/articles/s41419-020-03279-y