Balendiran Ganesaratnam K, Martin Hans-Joerg, El-Hawari Yasser, Maser Edmund
Department of Chemistry, Ward Beecher Science Hall, Youngstown State University, One University Plaza, Youngstown State University, OH 44555, USA.
Chem Biol Interact. 2009 Mar 16;178(1-3):134-7. doi: 10.1016/j.cbi.2008.10.044. Epub 2008 Nov 5.
A member of the aldo-keto reductase (AKR) protein superfamily, AKR1B10, is overexpressed in human liver cancers as well as in many adenocarcinoma cases due to smoking. AKR1B10 is also detected in instances of cervical and endometrial cancer in uterine cancer patients. In addition, AKR1B10 has been identified as a biomarker for non-small-cell lung cancer by a combined bioinformatics and clinical analysis. Furthermore, in breast cancer cells, fatty acid biosynthesis is regulated by AKR1B10. AKR1B10 contains 316 residues, shares 70% sequence identity with aldose reductase (AKR1B1) and has the conserved Cys residue at position 299. Carbonyl groups in some anticancer drugs and dl-glyceraldehyde are converted by AKR1B10 to their corresponding alcohols. The anticancer drug daunorubicin, which is currently used in the clinical treatment of various forms of cancer, is converted by AKR1B10 to daunorubicinol with a K(m) and k(cat) of 1.1+/-0.18 mM and 1.4+/-0.16 min(-1), respectively. This carbonyl reducing activity of AKR1B10 decreases the anticancer effectiveness of daunorubicin. Similarly, kinetic parameters K(m) and k(cat) (NADPH, DL-glyceraldehyde) for the reduction of dl-glyceraldehyde by wild-type AKR1B10 are 2.2+/-0.2 mM and 0.71+/-0.05 sec(-1), respectively. Mutation of residue 299 from Cys to Ser in AKR1B10 reduces the protein affinity for dl-glyceraldehyde and enhances AKR1B10's catalytic activity but overall catalytic efficiency is reduced. For dl-glyceraldehyde reduction that is catalyzed by the Cys299Ser mutant AKR1B10, K(m) is 15.8+/-1.0mM and k(cat) (NADPH, DL-glyceraldehyde) is 2.8+/-0.2 sec(-1). This implies that the substrate specificity of AKR1B10 is drastically affected by mutation of residue 299 from Cys to Ser. In the present paper, we use this mutation in AKR1B10 to characterize a library of compounds regarding their different inhibitory potency on the carbonyl reducing activity of wild-type and the Cys299Ser mutant AKR1B10.
醛酮还原酶（AKR）蛋白超家族成员AKR1B10在人类肝癌以及许多因吸烟导致的腺癌病例中过度表达。在子宫癌患者的宫颈癌和子宫内膜癌病例中也检测到了AKR1B10。此外，通过生物信息学和临床分析相结合，AKR1B10已被确定为非小细胞肺癌的生物标志物。此外，在乳腺癌细胞中，脂肪酸生物合成受AKR1B10调控。AKR1B10含有316个残基，与醛糖还原酶（AKR1B1）的序列同一性为70%，并在第299位含有保守的半胱氨酸残基。一些抗癌药物和dl-甘油醛中的羰基被AKR1B10转化为相应的醇。目前用于临床治疗各种癌症的抗癌药物柔红霉素被AKR1B10转化为柔红霉素醇，其米氏常数（K(m)）和催化常数（k(cat)）分别为1.1±0.18 mM和1.4±0.16 min(-1)。AKR1B10的这种羰基还原活性降低了柔红霉素的抗癌效果。同样，野生型AKR1B10还原dl-甘油醛的动力学参数K(m)和k(cat)（NADPH，DL-甘油醛）分别为2.2±0.2 mM和0.71±0.05 sec(-1)。AKR1B10中第299位残基从半胱氨酸突变为丝氨酸会降低蛋白质对dl-甘油醛的亲和力，并增强AKR1B10的催化活性，但总体催化效率降低。对于由半胱氨酸299丝氨酸突变体AKR1B10催化的dl-甘油醛还原反应，K(m)为15.8±1.0 mM，k(cat)（NADPH，DL-甘油醛）为2.8±0.2 sec(-1)。这意味着AKR1B10的底物特异性受到第299位残基从半胱氨酸突变为丝氨酸的显著影响。在本文中，我们利用AKR1B10中的这种突变来表征一系列化合物对野生型和半胱氨酸299丝氨酸突变体AKR1B10羰基还原活性的不同抑制效力。
