Zu Xuyu, Yan Ruilan, Pan Jishen, Zhong Linlin, Cao Yu, Ma Jun, Cai Chuan, Huang Dan, Liu Jianghua, Chung Fung-Lung, Liao Duan-Fang, Cao Deliang
Institute of Clinical Medicine, the First Affiliated Hospital of University of South China, Hengyang, Hunan, China.
Department of Medical Microbiology, Immunology and Cell Biology, Simmons Cancer Institute, Southern Illinois University School of Medicine, Springfield, Illinois.
Mol Carcinog. 2017 Jan;56(1):118-129. doi: 10.1002/mc.22477. Epub 2016 Mar 10.
Electrophilic carbonyl compounds are highly cytotoxic and genotoxic. Aldo-keto reductase 1B10 (AKR1B10) is an enzyme catalyzing reduction of carbonyl compounds to less toxic alcoholic forms. This study presents novel evidence that AKR1B10 protects colon cells from DNA damage induced by electrophilic carbonyl compounds. AKR1B10 is specifically expressed in epithelial cells of the human colon, but this study found that AKR1B10 expression was lost or markedly diminished in colorectal cancer, precancerous tissues, and a notable portion of normal adjacent tissues (NAT). SiRNA-mediated silencing of AKR1B10 in colon cancer cells HCT-8 enhanced cytotoxicity of acrolein and HNE, whereas ectopic expression of AKR1B10 in colon cancer cells RKO prevented the host cells against carbonyl cytotoxicity. Furthermore, siRNA-mediated AKR1B10 silencing led to DNA breaks and activation of γ-H2AX protein, a marker of DNA double strand breaks, particularly in the exposure of HNE (10 μM). In the AKR1B10 silenced HCT-8 cells, hypoxanthine-guanine phosphoribosyl transferase (HPRT) mutant frequency increased by 26.8 times at basal level and by 33.5 times in the presence of 10 μM HNE when compared to vector control cells. In these cells, the cyclic acrolein-deoxyguanosine adducts levels were increased by over 10 times. These findings were confirmed by pharmacological inhibition of AKR1B10 activity by Epalrestat. Taken together, these data suggest that AKR1B10 is a critical protein that protects host cells from DNA damage induced by electrophilic carbonyl compounds. AKR1B10 deficiency in the colon may be an important pathogenic factor in disease progression and carcinogenesis. © 2016 Wiley Periodicals, Inc.
亲电羰基化合物具有高度的细胞毒性和基因毒性。醛酮还原酶1B10（AKR1B10）是一种催化羰基化合物还原为毒性较低的醇类形式的酶。本研究提供了新的证据，表明AKR1B10可保护结肠细胞免受亲电羰基化合物诱导的DNA损伤。AKR1B10在人类结肠上皮细胞中特异性表达，但本研究发现，在结直肠癌、癌前组织以及相当一部分正常相邻组织（NAT）中，AKR1B10的表达缺失或明显减少。在结肠癌细胞HCT-8中，通过小干扰RNA（siRNA）介导沉默AKR1B10可增强丙烯醛和HNE的细胞毒性，而在结肠癌细胞RKO中异位表达AKR1B10可使宿主细胞抵抗羰基细胞毒性。此外，siRNA介导的AKR1B10沉默导致DNA断裂以及γ-H2AX蛋白激活，γ-H2AX蛋白是DNA双链断裂的标志物，尤其是在暴露于10μM HNE时。在AKR1B10沉默的HCT-8细胞中，与载体对照细胞相比，次黄嘌呤-鸟嘌呤磷酸核糖转移酶（HPRT）突变频率在基础水平增加了26.8倍，在存在10μM HNE时增加了33.5倍。在这些细胞中，环状丙烯醛-脱氧鸟苷加合物水平增加了10倍以上。依帕司他对AKR1B10活性的药理抑制作用证实了这些发现。综上所述，这些数据表明AKR1B10是一种关键蛋白，可保护宿主细胞免受亲电羰基化合物诱导的DNA损伤。结肠中AKR1B10的缺乏可能是疾病进展和致癌过程中的一个重要致病因素。©2016威利期刊公司
