Inactivation of JNK2 as carcinogenic factor in colitis-associated and sporadic colorectal carcinogenesis.
Carcinogenesis
; 38(5): 559-569, 2017 05 01.
Article
em En
| MEDLINE
| ID: mdl-28383667
ABSTRACT
We recently reported that dysregulated c-Jun N-terminal kinases (JNK) activity causes defective cell cycle checkpoint control, inducing neoplastic transformation in a cellular ulcerative colitis (UC) model. In the quiescent chronic phase of UC, p-p54 JNK was down-regulated and p-p46 JNK was up-regulated. Both were up-regulated in the acute phase. Consequently, increased p21WAF1 and γ-H2AX, two JNK-regulated proteins, induced cell cycle arrest. Their down-regulation led to checkpoint override, causing increased proliferation and undetected DNA damage in quiescent chronic phase, all characteristics of tumorigenesis. We investigated expression of p-JNK2, p-JNK1-3, p21WAF1, γ-H2AX and Ki67 by immunohistochemistry in cases of quiescent UC (QUC), active UC (AUC), UC-dysplasia and UC-related colorectal carcinoma (UC-CRC). Comparison was made to normal healthy colorectal mucosa, sporadic adenoma and colorectal carcinoma (CRC), diverticulitis and Crohns disease (CD). We found p-JNK2 up-regulation in AUC and its early down-regulation in UC-CRC and CRC carcinogenesis. With down-regulated p-JNK2, p21WAF1 was also decreased. Ki67 was inversely expressed, showing increased proliferation early in UC-CRC and CRC carcinogenesis. p-JNK1-3 was increased in AUC and QUC. Less increased γ-H2AX in UC-CRC compared to CRC gave evidence that colitis-triggered inflammation masks DNA damage, thus contributing to neoplastic transformation. We hypothesize that JNK-dependent cell cycle arrest is important in AUC, while chronic inflammation causes dysregulated JNK activity in quiescent phase that may contribute to checkpoint override, promoting UC carcinogenesis. We suggest restoring p-JNK2 expression as a novel therapeutic strategy to early prevent the development of UC-related cancer.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Neoplasias Colorretais
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Transformação Celular Neoplásica
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Colite
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Proteína Quinase 9 Ativada por Mitógeno
Tipo de estudo:
Prognostic_studies
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Risk_factors_studies
Limite:
Adolescent
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Adult
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Aged
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Aged80
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article