The status of phosphorylated p38 in esophageal squamous cell carcinoma.

The p38 mitogen-activated protein kinase (MAPK) is a member of the MAPK family, which is initially found to be activated by stress stimuli, proinflammatory cytokines, and growth factors. However, its role in the pathogenesis of esophageal squamous cell carcinoma (ESCC) is largely unkown, so we investigate the role of phosphorylated p38 (p-p38) MAPK in ESCC. First of all, in vitro cell line ECa109, SB203580 as selective inhibitor of p38, can suppress the growth of esophageal cancer cell in a dose- and time-dependent way, suggesting that ECa109 cell growth and proliferation was closely associated with p-p38. Using western-blot analysis of fresh 16 paired surgically resected ESCC and matched non-tumor adjacent tissues (NAT), we showed that p-p38 was significantly expressed higher in NAT compared to ESCC. Moreover, expressions of p-p38 were further confirmed by 162 paired of formalin-fixed paraffin-embedded (FFPE) ESCC and NAT by immunohistochemistry, the same trend result was obtained through statistical analysis that there was increased expression of p-p38 in NAT as compared with ESCC (P < 0.01), and expression of p-p38 was not significantly associated with lymph nodes metastasis (P > 0.05) and ESCC differentiation degree (P > 0.05). Taken together, all the results we obtained demonstrated that p-p38 plays a key role in the malignant transformation of ESCC.

Role of microRNA let-7 and effect to HMGA2 in esophageal squamous cell carcinoma.

To investigated the role of microRNA (miRNA) let-7 and its regulation on high mobility group A2 (HMGA2) protein expression in esophageal squamous cell carcinoma (ESCC). Let-7 expressions were detected in esophageal cancer cell line Eca109, and 45 paired of fresh ESCC and normal adjacent tissues (NAT) by real-time quantitative PCR (qRT-PCR). To evaluate the role of let-7 and HMGA2, cell proliferations were analyzed with synthetic let-7 mimics- or its inhibitor-transfected cells. Moreover, expressions of HMGA2 were performed by western blotting and further confirmed by 150 paired of formalin-fixed, paraffin-embeded (FFPE) ESCC and NAT by immunohistochemistry (IHC). In Eca109, when transfected with let-7 mimics, accumulation of let-7 was obviously suppressed cell proliferation with approximately 14%. Conversely, when Eca109 transfected with let-7 inhibitor, expression of let-7 was declined, which promoted cell proliferation with approximately 16%. Both of them had no effect on the level of HMGA2 mRNA. The transcription of let-7 inversely correlated with HMGA2 protein. Compared with the NAT, expression of let-7 was significantly lower in ESCC tissues (P < 0.05), and there was a significant correlation between low expression of let-7 and lymph node metastasis in ESCC (P < 0.05). Moreover, the protein expression of HMGA2 was significantly higher in ESCC compared with NAT (P < 0.05). However, mRNA expression of HMGA2 had no obvious significance between them. The present results demonstrated that let-7 and HMGA2 involved in ESCC carcinogenesis. Let-7 could inhibit cell proliferation and lower expressed in ESCC, and there was a correlation between let-7 lower expression and lymph node metastasis in ESCC patients. As well as, HMGA2 protein expression was significantly higher in ESCC than that in NAT, and HMGA2 may negatively regulated by let-7 at the post- transcriptional level in ESCC.