Leonel Camila, Gelaleti Gabriela B, Jardim Bruna V, Moschetta Marina G, Regiani Vitor R, Oliveira Juliana G, Zuccari Debora Apc
Departament of Molecular Biology, Faculdade de Medicina de São José do Rio Preto, FAMERP, São José do Rio Preto, SP, Brazil.
BMC Vet Res. 2014 Feb 24;10:49. doi: 10.1186/1746-6148-10-49.
Glutathione (GSH) is one of the most important agents of the antioxidant defense system of the cell because, in conjunction with the enzymes glutathione peroxidase (GSH-Px) and glutathione S transferase pi (GSTpi), it plays a central role in the detoxification and biotransformation of chemotherapeutic drugs. This study evaluated the expression of GSH and the GSH-Px and GSTpi enzymes by immunohistochemistry in 30 canine mammary tumors, relating the clinicopathological parameters, clinical outcome and survival of the bitches. In an in vitro study, the expression of the genes glutamate cysteine ligase (GCLC) and glutathione synthetase (GSS) that synthesize GSH and GSH-Px gene were verified by qPCR and subjected to treatment with doxorubicin, to check the resistance of cancer cells to chemotherapy.
The immunohistochemical expression of GSH, GSH-Px and GSTpi was compared with the clinical and pathological characteristics and the clinical outcome in the bitches, including metastasis and death.The results showed that high immunoexpression of GSH was correlated to the absence of tumor ulceration and was present in dogs without metastasis (P < 0.05). There was significant correlation of survival with the increase of GSH (P < 0.05). The expression of the GSH-Px and GSTpi enzymes showed no statistically significant correlation with the analyzed variables (p > 0.05). The analysis of the relative expression of genes responsible for the synthesis of GSH (GCLC and GSS) and GSH-Px by quantitative PCR was done with cultured cells of 10 tumor fragments from dogs with mammary tumors.The culture cells showed a decrease in GCLC and GSS expression when compared with no treated cells (P < 0.05). High GSH immunoexpression was associated with better clinical outcomes.
Therefore, high expression of the GSH seems to play an important role in the clinical outcome of patients with mammary tumors and suggest its use as prognostic marker. The in vitro doxorubicin treatment significantly reduces the expression of GCLC and GSS genes so we can consider them to be candidates for predictive markers of therapeutic response in mammary cancer.
谷胱甘肽（GSH）是细胞抗氧化防御系统中最重要的物质之一，因为它与谷胱甘肽过氧化物酶（GSH-Px）和谷胱甘肽S转移酶pi（GSTpi）协同作用，在化疗药物的解毒和生物转化中发挥核心作用。本研究通过免疫组织化学评估了30例犬乳腺肿瘤中GSH、GSH-Px和GSTpi酶的表达，并将其与母犬的临床病理参数、临床结局和生存率相关联。在一项体外研究中，通过定量聚合酶链反应（qPCR）验证了合成GSH的谷氨酸半胱氨酸连接酶（GCLC）和谷胱甘肽合成酶（GSS）基因以及GSH-Px基因的表达，并对其进行阿霉素处理，以检查癌细胞对化疗的耐药性。
将GSH、GSH-Px和GSTpi的免疫组织化学表达与母犬的临床和病理特征以及临床结局（包括转移和死亡）进行了比较。结果表明，GSH的高免疫表达与肿瘤无溃疡相关，且在无转移的犬中存在（P < 0.05）。生存率与GSH的增加存在显著相关性（P < 0.05）。GSH-Px和GSTpi酶的表达与分析变量无统计学显著相关性（p > 0.05）。使用来自患有乳腺肿瘤的犬的10个肿瘤片段的培养细胞，通过定量PCR对负责合成GSH（GCLC和GSS）和GSH-Px的基因的相对表达进行了分析。与未处理的细胞相比，培养细胞显示GCLC和GSS表达降低（P < 0.05）。高GSH免疫表达与更好的临床结局相关。
因此，GSH的高表达似乎在乳腺肿瘤患者的临床结局中起重要作用，并提示其可作为预后标志物。体外阿霉素处理显著降低了GCLC和GSS基因的表达，因此我们可以认为它们是乳腺癌治疗反应预测标志物的候选者。
