ABSTRACT
Objective To inquire into the expression and its clinical significance of sulfiredoxin (Srx) in cervical squamous cell carcinoma tissue. Methods SABC immunohistochemical method was used to detect the expression levels of Srx in specimens of 104 cervical squamous cell carcinoma and the corresponding adjacent tissues, 15 cervical intraepithelial neoplasm (CIN Ⅲ), and 20 normal cervical squamous cell epithelium tissue. The relationship between the expression of Srx protein and clinical pathological parameters of the cancer was also analyzed. Results The positive expression rates of Srx in CIN Ⅲ and cervical squamous cell carcinoma [73.3%(11/15) and 82.7%(86/104), respectively] were significantly higher than that in normal cervical tissue [35.0%(7/20), χ2=17.778, P=0.000]. Meanwhile, Srx expression in cervical cancer specimens was significantly higher than that in normal adjacent tissues (χ2=56.224, P=0.000). The positive expression of Srx in cervical squamous cell carcinoma was significantly correlated with lymph node metastasis, the depth of cancer invasion, and the infiltration of blood vessels (P0.05). Conclusion The higher expression of Srx protein might be a valuable marker for the early diagnosis and evaluation of prognosis in patients with cervical squamous cell carcinoma.
ABSTRACT
BACKGROUND/AIMS: Oxidative stress results in protein oxidation and is implicated in carcinogenesis. Sulfiredoxin (Srx) is responsible for the enzymatic reversal of inactivated peroxiredoxin (Prx). Nuclear factor E2-related factor 2 (Nrf2) binds to antioxidant responsive elements and upregulates the expression of Srx and Prx during oxidative stress. We aimed to elucidate the biological functions and potential roles of Srx in lung cancer. METHODS: To study the roles of Srx and Prx III in lung cancer, we compared the protein levels of Nrf2, Prxs, thioredoxin, and Srx in 40 surgically resected human lung cancer tissues using immunoblot and immunohistochemical analyses. Transforming growth factor-beta1, tumor necrosis factor-alpha, and camptothecin treatment were used to examine Prx III inactivation in Mv1Lu mink lung epithelial cells and A549 lung cancer cells. RESULTS: Prx I and Prx III proteins were markedly overexpressed in lung cancer tissues. A significant increase in the oxidized form of a cysteine sulfhydryl at the catalytic site of Prxs was found in carcinogenic lung tissue compared to normal lung tissue. Densitometric analyses of immunoblot data revealed significant Srx expression, which was higher in squamous cell carcinoma tissue (60%, 12/20) than in adenocarcinoma (20%, 4/20). Also, Nrf2 was present in the nuclear compartment of cancer cells. CONCLUSIONS: Srx and Prx III proteins were markedly overexpressed in human squamous cell carcinoma, suggesting that these proteins may play a protective role against oxidative injury and compensate for the high rate of mitochondrial metabolism in lung cancer.