OBJECTIVETo investigate the expression variation and significance of ERK1/2 MAPK signaling transduction pathway in the pathogenesis of esophageal squamous cell carcinoma (ESCC) in Kazakh patients.

METHODSThe expression level of p-ERK1/2 after serum starvation and treatment with U0126 inhibitor was detected in esophageal cancer cell line EC9706 by Western blot assay. The mRNA level of total ERK1/2 (t-ERK1/2) and expression level of t-ERK1/2 and p-ERK1/2 proteins of 25 pairs of ESCC and adjacent normal esophageal mucosal tissues of Kazakh patients were examined and identified by real-time quantitative PCR (qRT-PCR) and Western blotting, respectively. The expression of p-ERK1/2 protein was verified by immunohistochemistry in 126 paraffin-embeded specimens, including 19 normal esophageal mucosa, 55 esophageal carcinomas in situ and 52 invasive carcinomas.

RESULTSERK1/2 MAPK signaling transduction pathway was in an active status in the EC9706 cells. The expression level of p-ERK1/2 in Ec9706 cells reached a peak at 10 min after transient serum stimulation, and p-ERK1/2 expression was totally restrained after the treatment with 50 µmol/L U0126. In the 25 pairs of ESCC and adjacent normal mucosa, the t-ERK1 mRNA level was 1.92 ± 3.49 in the ESCC tissues and 3.67 ± 7.47 in the adjacent normal mucosa. The t-ERK1 mRNA level in ESCC tissues was significantly lower than that in adjacent normal mucosa (P < 0.05), whereas there was no significant difference of t-ERK2 mRNA level between them(P > 0.05). The expression levels of p-ERK1 and p-ERK2 proteins were 0.87 ± 0.14 and 0.79 ± 0.10 in the ESCC tissues, and 1.10 ± 0.13 and 1.32 ± 0.12 in the adjacent normal mucosae. p-ERK1/2 protein in the ESCC tissues was significantly lower than that in the adjacent normal tissue (P < 0.01). However, there was no significant difference between their t-ERK1/2 protein levels (P > 0.05). In the 126 cases of paraffin-embeded specimens, positive expressions of both p-ERK1 and p-ERK2 in esophageal cancer tissues were 7.7% (4/52), significantly lower than those in adjacent normal mucosa (31.6%, 6/19) and carcinoma in situ (85.5%, 47/55, P < 0.05).

CONCLUSIONSERK1/2 MAPK signaling pathway is in an active status in esophageal cancer and adjacent normal mucosa. Our results imply that the activation of p-ERK1/2 MAPK signaling transduction pathway plays a role in the early pathogenesis of ESCC in Kazakh patients.

Butadienes ; pharmacology ; Carcinoma in Situ ; enzymology ; pathology ; Carcinoma, Squamous Cell ; enzymology ; pathology ; Cell Line, Tumor ; China ; ethnology ; Enzyme Inhibitors ; pharmacology ; Esophageal Neoplasms ; enzymology ; pathology ; Gene Expression Regulation, Neoplastic ; Humans ; MAP Kinase Signaling System ; Mitogen-Activated Protein Kinase 1 ; genetics ; metabolism ; Mitogen-Activated Protein Kinase 3 ; genetics ; metabolism ; Nitriles ; pharmacology ; Phosphorylation ; RNA, Messenger ; metabolism

Aim To investigate the effect of quercetin(Que)on podocyte inflammatory injury and the under-lying mechanism.Methods MPC5 cells were divided into normal glucose group(NG),mannitol group(MA),high glucose group(HG)and high glucose+quercetin group(HG+Que).Cell proliferation and apoptosis were detected by CCK-8 and flow cytometry.The expression of SIRT1,STAT3,apoptosis-related proteins(Bax,Bcl-2,caspase-3)and pyroptosis pro-tein GSDME was detected by Western blot.The ex-pression levels of inflammatory factors(IL-6,TNF-α,IL-18,IL-1β)in cell supernatants were detected by ELISA.Then small interfering RNA technology was used to knockdown SIRT1 expression.To further eval-uate the biological significance of SIRT1 in response to high glucose and Que treatment,negative control group(HG+si-NC+Que)and SIRT1 interference group(HG+si-SIRT1+Que)were added in the presence of high glucose and Que.Results Compared with the high glucose group,40 μmol·L-1 Que could alleviate the apoptosis of MPC5 cells induced by high glucose,decrease the expression of apoptosis related protein Bax and caspase-3,as well as increase the expression of anti-apoptotic protein Bcl-2;ELISA results showed that Que could decrease the expression of TNF-α,IL-6,IL-1 β and IL-18 induced by high glucose.Mechanical-ly,Que could alleviate the inhibitory effect of high glu-cose on the expression of SIRT1,and further decrease the activation of STAT3 and N-GSDME,and inhibit pyroptosis.Compared with the si-NC group,si-SIRT1 group could reverse the protective effect of Que on the high glucose induced inflammatory damage of podo-cytes,the expression of apoptotic proteins Bax and caspase-3 increased,while the expression of anti-apop-totic protein Bcl-2 decreased.At the same time,the levels of inflammatory cytokines TNF-α,IL-6,IL-1 βand IL-18 in supernatants increased,and the expres-sion of STAT3 and N-GSDME increased.Conclusion Que could inhibit pyroptosis and relieve the inflam-matory damage of podocytes through SIRT1/STAT3/GSDME pathway.