RESUMO
Background/Aims@#Esophagogastric junction adenocarci-noma (EJA) is a malignant tumor associated with high mor-bidity and has attracted increasing attention due to a rising incidence and low survival rate. Pathological biopsy is the gold standard for diagnosis, but noninvasive and effective tests are lacking, resulting in diagnoses at advanced stages.This study explored the diagnostic value of insulin-like growth factor binding protein 7 (IGFBP7) in EJA. @*Methods@#A total of 120 EJA patients and 88 normal controls were recruited, and their serum levels of IGFBP7 were measured by enzymelinked immunosorbent assay. Receiver operating character-istic (ROC) curve analysis was used to assess the diagnostic value, and Pearson chi-square analysis was used to evaluate the correlation between IGFBP7 and clinical parameters. Ka-plan-Meier survival analysis was carried out to assess the ef-fect of IGFBP7 on overall survival (OS). @*Results@#The levels of IGFBP7 were higher in both early- and late-stage EJA patients than in normal controls (p<0.001). The area under the ROC curve for EJA patients was 0.794 (95% confidence interval [CI], 0.733 to 0.854), with a cutoff value of 2.716 ng/mL, a sensitivity of 63.3% (95% CI, 54.0% to 71.8%) and a specific-ity of 90.9% (95% CI, 82.4% to 95.7%). For the diagnosis of early-stage EJA, the same cutoff value and specificity were obtained, but the sensitivity of IGFBP7 was 54.3% (95% CI, 36.9% to 70.8%). Patients with low IGFBP7 protein expres-sion had lower OS than those with high expression (p=0.034).The multivariate analysis showed that IGFBP7 is an inde-pendent prognostic factor for EJA (p=0.011). @*Conclusions@#Serum IGFBP7 acts as a potential diagnostic and prognostic marker for EJA.
RESUMO
Transcription factors of the FoxO (forkhead box O) family regulate a wide range of cellular physiological processes, including metabolic adaptation and myogenic differentiation. The transcriptional activity of most FoxO members is inhibitory to myogenic differentiation and overexpression of FoxO1 inhibits the development of oxidative type I fibres in vivo. In this study, we found that FoxO6, the last discovered FoxO family member, is expressed ubiquitously in various tissues but with higher expression levels in oxidative tissues, such as brain and oxidative muscles. Both the expression level and promoter activity of FoxO6 were found to be enhanced by PGC-1α (peroxisome-proliferator-activated receptor γ co-activator 1α), thus explained its enriched expression in oxidative tissues. We further demonstrated that FoxO6 represses the expression of PGC-1α via direct binding to an upstream A/T-rich element (AAGATATCAAAACA,-2228-2215) in the PGC-1α promoter. Oxidative low-intensity exercise induced PGC-1α but reduced FoxO6 expression levels in hind leg muscles, and the binding of FoxO6 to PGC-1α promoter was also prevented by exercise. As FoxO6 promoter can be co-activated by PGC-1α and its promoter in turn can be repressed by FoxO6, it suggests that FoxO6 and PGC-1α form a regulatory loop for setting oxidative metabolism level in the skeletal muscle, which can be entrained by exercise.
