Macrophage migration inhibitory factor as a potential prognostic factor in gastric cancer

AIM:To investigate macrophage migration inhibitory factor(MIF) expression and its clinical relevance in gastric cancer,and effects of MIF knockdown on proliferation of gastric cancer cells. METHODS:Tissue microarray containing 117 samples of gastric cancer and adjacent non-cancer normal tissues was studied for MIF expression by immunohistochemistry(IHC) semiquantitatively,and the association of MIF expression with clinical parameters was analyzed. MIF expression in gastric cancer cell lines was detected by reverse transcriptionpolymerase chain reaction(RT-PCR) and Western blot. Two pairs of si RNA targeting the MIF gene(MIF si-1 and MIF si-2) and one pair of scrambled si RNA as a negative control(NC) were designed and chemically synthesized. All si RNAs were transiently transfected in AGS cells with OligofectamineTM to knock down the MIF expression,with the NC group and mock group(OligofectamineTM alone) as controls. At 24,48,and 72 h after transfection,MIF m RNA was analyzed by RTPCR,and MIF and proliferating cell nuclear antigen(PCNA) proteins were detected by Western blot.The proliferative rate of AGS cells was assessed by methylthiazolyl tetrazolium(MTT) assay and colony forming assay.RESULTS:The tissue microarray was informative for IHC staining,in which the MIF expression in gastric cancer tissues was higher than that in adjacent noncancer normal tissues(P < 0.001),and high level of MIF was related to poor tumor differentiation,advanced T stage,advanced tumor stage,lymph node metastasis,and poor patient survival(P < 0.05 for all). After si RNA transfection,MIF m RNA was measured by real-time PCR,and MIF protein and PCNA were assessed by Western blot analysis. We found that compared to the NC group and mock group,MIF expression was knocked down successfully in gastric cancer cells,and PCNA expression was downregulated with MIF knockdown as well. The cell counts and the doubling times were assayed by MTT 4 d after transfection,and colonies formed were assayed by colony forming assay 10 d after transfection; all these showed significant changes in gastric cancer cells transfected with specific si RNA compared with the control si RNA and mock groups(P < 0.001 for all).CONCLUSION:MIF could be of prognostic value in gastric cancer and might be a potential target for small-molecule therapy.

Yangzheng Sanjie decoction regulates proliferation and apoptosis of gastric cancer cells by enhancing let-7a expression

AIM To explore the let-7a-mediated anti-cancer effect of Yangzheng Sanjie decoction(YZSJD) in gastric cancer(GC) cells.METHODS YZSJD-containing serum(YCS) was prepared using traditional Chinese medicine serum pharmacology methods. After YCS treatment, cell proliferation and apoptosis were assessed by cell counting kit-8 assay and flow cytometry, respectively, and mi RNA expression profiles were determined using q PCR arrays. Let-7a expression was examined by in situ hybridization in GC tissues and by q PCR in GC cells. c-Myc protein expression was detected by immunohistochemistry in GC tissues, and by Western blot in cell lines.RESULTS YZSJD significantly inhibited proliferation and induced apoptosis in AGS and HS-746 T GC cells. After treatment with YCS, the mi RNA expression profiles were altered and the reduced let-7a levels in both cell lines were up-regulated, accompanied by a decrease in c-Myc expression. Moreover, decreased let-7a expression and increased c-Myc expression were observed during the progression of gastric mucosa cancerization.CONCLUSION YZSJD inhibits proliferation and induces apoptosis of GC cells by restoring the aberrant expression of let-7a and c-Myc.

Role of microRNA-7 in digestive system malignancy

There are several malignancies of the digestive system(including gastric, pancreatic and colorectal cancers, and hepatocellular carcinoma), which are the most common types of cancer and a major cause of death worldwide. MicroRNA(miR)-7 is abundant in the pancreas, playing an important role in pancreatic development and endocrine function. Expression of miR-7 is downregulated in digestive system malignancies compared with normal tissue. Although there are contrasting results for miR-7 expression, almost all research reveals that miR-7 is a tumor suppressor, by targeting various genes in specific pathways. Moreover, miR-7 can target different genes simultaneously in different malignancies of the digestive system. By acting on many cytokines, miR-7 is also involved in many gastrointestinal inflammatory diseases as a significant carcinogenic factor. Consequently, miR-7 might be a biomarker or therapeutic target gene in digestive system malignancies.