RESUMO
The current study was carried out to define the involvement of Peroxiredoxin (Prx) II in progression of hepatocellular carcinoma (HCC) and the underlying molecular mechanism(s). Expression and function of Prx II in HCC was determined using H-ras(G12V)-transformed HCC cells (H-ras(G12V)-HCC cells) and the tumor livers from H-ras(G12V)-transgenic (Tg) mice and HCC patients. Prx II was upregulated in H-ras(G12V)-HCC cells and H-ras(G12V)-Tg mouse tumor livers, the expression pattern of which highly similar to that of forkhead Box M1 (FoxM1). Moreover, either knockdown of FoxM1 or site-directed mutagenesis of FoxM1-binding site of Prx II promoter significantly reduced Prx II levels in H-ras(G12V)-HCC cells, indicating FoxM1 as a direct transcription factor of Prx II in HCC. Interestingly, the null mutation of Prx II markedly decreased the number and size of tumors in H-ras(G12V)-Tg livers. Consistent with this, knockdown of Prx II in H-ras(G12V)-HCC cells reduced the expression of cyclin D1, cell proliferation, anchorage-independent growth and tumor formation in athymic nude mice, whereas overexpression of Prx II increased or aggravated the tumor phenotypes. Importantly, the expression of Prx II was correlated with that of FoxM1 in HCC patients. The activation of extracellular signal-related kinase (ERK) pathway and the expression of FoxM1 and cyclin D1 were highly dependent on Prx II in H-ras(G12V)-HCC cells and H-ras(G12V)-Tg livers. Prx II is FoxM1-dependently-expressed antioxidant in HCC and function as an enhancer of Ras(G12V) oncogenic potential in hepatic tumorigenesis through activation of ERK/FoxM1/cyclin D1 cascade.
Assuntos
Transformação Celular Neoplásica/genética , Proteína Forkhead Box M1/genética , Fígado/metabolismo , Peroxirredoxinas/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Animais , Western Blotting , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Células Cultivadas , Feminino , Proteína Forkhead Box M1/metabolismo , Regulação Neoplásica da Expressão Gênica , Células Hep G2 , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Camundongos , Camundongos Knockout , Camundongos Nus , Camundongos Transgênicos , Células NIH 3T3 , Peptídeos/farmacologia , Peroxirredoxinas/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Transplante HeterólogoRESUMO
A rare occurrence of primary adenocarcinoma arising in an interposed colon nearly seven years after the surgery is described. Remarkably, there were no symptoms from a large mass in the transposed bowel. Diagnosis was made fortuitously while searching for the cause of the patient's iron-deficiency anemia. The rationale for careful preoperative screening of the colonic segment intended for transplant to exclude pre-existing pathology is reemphasized. The various methods of evaluating the postoperative colon graft and their advantages and limitations are discussed.
