[Detection and analysis of the characteristic expression of microRNAs of anal fistula patients].

OBJECTIVE: To detect and analyze the characteristic miRNAs profile of anal fistula and explore their possible target genes and potential clinical significance. METHODS: The anal mucosa close to the hemorrhoids were collected from three patients undergoing fistulectomy and hemorrhoidectomy (fistula group) as well as three patients receiving only hemorroidectomy(hemorrhoids group), matching with fistula group in age, gender and body weight. miRNA microarray was used to compare the expression of 1 285 human miRNAs of the anal mucosa between two groups. Cluster analysis was adopted to analyze the accumulation of the differentially expressed miRNAs(P<0.05, fold≥2.0 or ≤0.5) and their target genes were predicted with 10 softwares such as DIANAmT, miRanda, miRDB, miRWalk etc. Comprehensive scoring was performed to identify genes with highest predictive score. Gene ontology (GO) concentration technique was used to analyze the target gene-associated biological process. Immunohistochemistry was used to examine protein expression of genes with the highest score. RESULTS: Among 1285 miRNAs in fistula group, 13 miRNAs were differentially expressed with those in hemorrhoid group, including 2 of up-regulation and 11 of down-regulation. Paired t test showed that in fistula group, miRNA-3609 up-regulation was 5.98 folds(P=0.0231) and miR-181a-2-3p down-regulation was 0.13 folds(P=0.0067) compared to those in hemorrhoid group, which had the greatest differential expression. Cluster analysis suggested that up-regulated miR-3609 and miR-6086 had similar change trend in both groups. Among 11 down-regulated miRNAs, miR-125bp-1-3p and miR-548q had similar expression and other 9 miRNAs had similar expression as well, including miR-1185-1-3p, miR-532-3p, miR-1233-5p, miR-769-5p, miR-149-5p, miR-99b-3p, miR-141-3p, miR-138-5p, and miR-181a-2-3p. Target gene prediction analysis of above 13 genes showed that 7 miRNAs(53.8%) were eligible to predict their potential target genes, yielding totally 104 possible target genes. The rest of 6 miRNAs(46.2%) failed to predict any target gene. The highest score in prediction of target gene was chitinase 1(ChIT1) and its corresponding differential miRNA was miR-769-5p(r=-0.94286, P=0.0167). Gene ontology analysis showed that the most associated biological process related with these 104 target genes was keratinization, immune response and signal transduction. Immunohistochemistry revealed ChiT1 expression of anal mucosa in fistula group was significantly higher compared to hemorrhoid group(P<0.01). CONCLUSIONS: There is a characteristic miRNAs profile in anal fistula patients, which may play a role in the occurrence and development of anal fistula.

Perianal Paget's Disease Co-Associated with Anorectal Adenocarcinoma: Primary or Secondary Disease?

Perianal Paget's disease (PPD) represents a skin neoplasm which can be either primary or secondary to carcinoma from an adjacent internal organ. PPD with underlying colorectal adenocarcinoma is usually looked upon as a secondary disease. We report a rare case of co-associated PPD and anorectal adenocarcinoma. The PPD was found to be located near the anorectal adenocarcinoma with normal tissues between them. Immunohistochemical stains demonstrated that the Paget's cells were CK7+/GCDFP-15-/CK20-/MUC2-/CDX2-, whereas the anorectal adenocarcinoma was shown to be CK7+/GCDFP-15-/CK20+/MUC2+/CDX2+. This immunological phenotypic profile supported the notion that PPD and anorectal adenocarcinoma were of different origins, but could not define the exact origins of PPD. In our determination, this case was a primary PPD with anorectal adenocarcinoma. PPD remains a heterogeneous and complex pathology, and additional studies are required to differentiate between the various possible origins.

Human phosphatidylethanolamine-binding protein 4 promoted the radioresistance of human rectal cancer by activating Akt in an ROS-dependent way.

Human phosphatidylethanolamine-binding protein 4(hPEBP4) is a novel anti-apoptosis molecule associated with the resistance of tumors to apoptotic agents. Here we sought to investigate the role of hPEBP4 in the radioresistance of rectal cancer. Immunohistochemistry analysis showed hPEBP4 was expressed in 27/33 of rectal cancer specimens, but only in 2/33 of neighboring normal mucosa. Silencing the expression of hPEBP4 with siRNA significantly reduced the clonogenic survival and enhanced the apoptosis of rectal cancer cells on irradiation. Instead, forced overexpression of hPEBP4 promoted its survival and decreased the apoptosis. Western blot showed hPEBP4 could increase the radiation-induced Akt activation, for which reactive oxygen specimen(ROS) was required. The radioresistance effect of hPEBP4 was reversed after given LY-294002 to inhibit Akt activation or antioxidant to abolish the ROS production. We also confirmed that effect of hPEBP4 in vivo with nude mice. Thus we concluded that hPEBP4, specifically expressed in rectal cancer cells, is associated with radioresistance of rectal cancer, implying that modulation of hPEBP4 may have important therapeutic implications in radiotherapy of rectal cancer.