Albin N, Massaad L, Toussaint C, Mathieu M C, Morizet J, Parise O, Gouyette A, Chabot G G
Département de Pharmaco-toxicologie et Pharmacogénétique (INSERM U 140 and CNRS URA 147, Villejuif, France.
Cancer Res. 1993 Aug 1;53(15):3541-6.
In an attempt to better understand breast tumors sensitivity or resistance to anticancer drugs, the main drug-metabolizing enzyme systems were evaluated in both breast tumors and their corresponding peritumoral tissues in 12 patients. The following enzymes were assayed by Western blot: cytochromes P-450 (1A1/A2, 2B1/B2, 2C8-10, 2E1, 3A4); glutathione S-transferases (GST-alpha, -mu, and -pi); and epoxide hydrolase. The activity of the following enzymes or cofactor were determined by spectrophotometric or fluorometric assays: GST; total glutathione; UDP-glucuronosyltransferase; beta-glucuronidase; sulfotransferase; and sulfatase. Results showed the absence of all probed cytochromes P-450 in both tumoral and peritumoral tissues. GST activity was significantly (P < 0.05) higher in tumors (mean +/- SD, 399 +/- 362 nmol/min/mg) than in corresponding peritumoral tissues (86 +/- 67). The GST isoenzymes GST-mu and GST-pi (determined by immunoblotting) were also higher in tumors than in corresponding peritumoral tissues (3- and 5-fold, respectively). Both GST-mu and GST-pi levels were significantly correlated with GST activity. GST-alpha was not detected in either tumoral or peritumoral tissues. Glutathione levels in tumors (22 +/- 23 nmol/mg protein) were not statistically different from peritumoral tissues (11 +/- 12). Epoxide hydrolase was expressed at similar levels in tumors and peritumoral tissues. The glucuronide-forming enzyme UDP-glucuronosyltransferase was 5-fold lower in tumors (0.1 +/- 0.2 nmol/h/mg) than in peritumoral tissues (0.5 +/- 1), whereas the opposite was observed for the hydrolytic enzyme beta-glucuronidase, which was 6-fold higher in tumors (736 +/- 1392 nmol/h/mg) compared to peritumoral tissues (125 +/- 75). No difference was noted between tumoral and peritumoral tissues for sulfotransferase (1 +/- 2 nmol/h/mg), but the corresponding hydrolytic enzyme (sulfatase) was 2-fold higher in tumoral tissues (14 +/- 15 nmol/h/mg) than in peritumoral tissues (6 +/- 2). In conclusion, several differences were observed between human breast tumors and peritumoral tissues for many conjugating enzymes (GST-mu, GST-pi, and UDP-glucuronosyltransferase) and hydrolytic enzymes (sulfatase and beta-glucuronidase). These noteworthy differences between tumoral and peritumoral tissues with regard to their main drug-metabolizing enzymes could play a role in the relative drug sensitivity or insensitivity of human breast cancer tissues to chemotherapeutic agents and could be potential targets for chemotherapeutic interventions.
为了更好地了解乳腺肿瘤对抗癌药物的敏感性或耐药性，对12例患者的乳腺肿瘤及其相应的瘤周组织中的主要药物代谢酶系统进行了评估。通过蛋白质印迹法检测了以下几种酶：细胞色素P-450（1A1/A2、2B1/B2、2C8 - 10、2E1、3A4）；谷胱甘肽S-转移酶（GST-α、-μ和-π）；以及环氧化物水解酶。通过分光光度法或荧光测定法测定了以下几种酶或辅助因子的活性：GST；总谷胱甘肽；尿苷二磷酸葡萄糖醛酸基转移酶；β-葡萄糖醛酸酶；磺基转移酶；以及硫酸酯酶。结果显示，在肿瘤组织和瘤周组织中均未检测到所有被检测的细胞色素P-450。肿瘤组织中的GST活性（平均值±标准差，399±362 nmol/min/mg）显著高于相应的瘤周组织（86±67）（P<0.05）。通过免疫印迹法测定的GST同工酶GST-μ和GST-π在肿瘤组织中也高于相应的瘤周组织（分别为3倍和5倍）。GST-μ和GST-π的水平均与GST活性显著相关。在肿瘤组织和瘤周组织中均未检测到GST-α。肿瘤组织中的谷胱甘肽水平（22±23 nmol/mg蛋白质）与瘤周组织（11±12）无统计学差异。环氧化物水解酶在肿瘤组织和瘤周组织中的表达水平相似。形成葡萄糖醛酸苷的酶尿苷二磷酸葡萄糖醛酸基转移酶在肿瘤组织中的活性（0.1±0.2 nmol/h/mg）比瘤周组织（0.5±1）低5倍，而水解酶β-葡萄糖醛酸酶则相反，其在肿瘤组织中的活性（736±1392 nmol/h/mg）比瘤周组织（125±75）高6倍。肿瘤组织和瘤周组织中的磺基转移酶活性（1±2 nmol/h/mg）无差异，但相应的水解酶（硫酸酯酶）在肿瘤组织中的活性（14±15 nmol/h/mg）比瘤周组织（6±2）高2倍。总之，在人乳腺肿瘤组织和瘤周组织之间，观察到许多结合酶（GST-μ、GST-π和尿苷二磷酸葡萄糖醛酸基转移酶）和水解酶（硫酸酯酶和β-葡萄糖醛酸酶）存在差异。肿瘤组织和瘤周组织在其主要药物代谢酶方面的这些显著差异可能在人乳腺癌组织对化疗药物的相对敏感性或不敏感性中起作用，并且可能是化疗干预的潜在靶点。
