Gene regulation by antitumor miR-130b-5p in pancreatic ductal adenocarcinoma: the clinical significance of oncogenic EPS8.

Our ongoing analyses identifying dysregulated microRNAs (miRNAs) and their controlled target RNAs have shed light on novel oncogenic pathways in pancreatic ductal adenocarcinoma (PDAC). The PDAC miRNA signature obtained by RNA sequencing showed that both strands of pre-miR-130b (miR-130b-5p, the passenger strand and miR-130b-3p, the guide strand) were significantly downregulated in cancer tissues. Our functional assays revealed that miR-130b-5p significantly blocked the malignant abilities of PDAC cell lines (PANC-1 and SW1990), e.g., cancer cell proliferation, migration, and invasion. A total of 103 genes were identified as possible oncogenic targets by miR-130b-5p regulation in PDAC cells based on genome-wide gene expression analysis and in silico database search. Among the possible targets, high expression of 9 genes (EPS8, ZWINT, SMC4, LDHA, GJB2, ZCCHC24, TOP2A, ANLN, and ADCY3) predicted a significantly poorer prognosis of PDAC patients (5-year overall survival, p < 0.001). Furthermore, we focused on EPS8 because its expression had the greatest impact on patient prognosis (overall survival, p < 0.0001). Overexpression of EPS8 was detected in PDAC clinical specimens. Knockdown assays with siEPS8 showed that its overexpression enhanced cancer cell proliferation, migration, and invasion. Analysis of downstream RNA networks regulated by EPS8 indicated that MET, HMGA2, FERMT1, RARRES3, PTK2, MAD2L1, and FLI1 were closely involved in PDAC pathogenesis. Genes regulated by antitumor miR-130b-5p were closely involved in PDAC molecular pathogenesis. Our approach, discovery of antitumor miRNAs and their target RNAs, will contribute to exploring the causes of this malignant disease.

Gene Regulation by Antitumor miR-204-5p in Pancreatic Ductal Adenocarcinoma: The Clinical Significance of Direct RACGAP1 Regulation.

Previously, we established a microRNA (miRNA) expression signature in pancreatic ductal adenocarcinoma (PDAC) tissues using RNA sequencing and found significantly reduced expression of miR-204-5p. Here, we aimed to investigate the functional significance of miR-204-5p and to identify miR-204-5p target genes involved in PDAC pathogenesis. Cancer cell migration and invasion were significantly inhibited by ectopic expression of miR-204-5p in PDAC cells. Comprehensive gene expression analyses and in silico database searches revealed 25 putative targets regulated by miR-204-5p in PDAC cells. Among these target genes, high expression levels of RACGAP1, DHRS9, AP1S3, FOXC1, PRP11, RHBDL2 and MUC4 were significant predictors of a poor prognosis of patients with PDAC. In this study, we focused on RACGAP1 (Rac guanosine triphosphatase-activating protein 1) because its expression was most significantly predictive of PDAC pathogenesis (overall survival rate: p = 0.0000548; disease-free survival rate: p = 0.0014). Overexpression of RACGAP1 was detected in PDAC clinical specimens, and its expression enhanced the migration and invasion of PDAC cells. Moreover, downstream genes affected by RACGAP1 (e.g., MMP28, CEP55, CDK1, ANLN and S100A14) are involved in PDAC pathogenesis. Our strategy to identify antitumor miRNAs and their target genes will help elucidate the molecular pathogenesis of PDAC.

Involvement of anti-tumor miR-124-3p and its targets in the pathogenesis of pancreatic ductal adenocarcinoma: direct regulation of ITGA3 and ITGB1 by miR-124-3p.

MicroRNAs (miRNAs) are unique in that a single miRNA molecule regulates a vast number of RNA transcripts. Thus, aberrantly expressed miRNAs disrupt tightly controlled RNA networks in cancer cells. Our functional screening showed that expression of miR-124-3p was downregulated in pancreatic ductal adenocarcinoma (PDAC) tissues. Here, we aimed to investigate the anti-tumor roles of miR-124-3p in PDAC cells and to identify miR-124-3p-mediated oncogenic signaling in this disease. Ectopic expression of miR-124-3p inhibited cancer cell migration and invasion in PDAC cells. Moreover, restoration of miR-124-3p suppressed oncogenic signaling, as demonstrated by reduced phosphorylation of focal adhesion kinase, AKT, and extracellular signal-regulated kinase, in PDAC cells. Our in silico database analyses and luciferase reporter assays showed that two cell-surface matrix receptors, integrin α3 (ITGA3) and integrin ß1 (ITGB1), were directly regulated by miR-124-3p in PDAC cells. Overexpression of ITGA3 and ITGB1 was confirmed in PDAC clinical specimens. Interestingly, a large number of cohort analyses from TCGA database showed that high expressions of ITGA3 and ITGB1 were significantly associated with poor prognosis of patients with PDAC. Knockdown of ITGA3 and ITGB1 by siRNAs markedly suppressed the migration and invasion abilities of PDAC cells. Moreover, downstream oncogenic signaling was inhibited by ectopic expression of miR-124-3p or knockdown of the two integrins. The discovery of anti-tumor miRNAs and miRNA-mediated oncogenic signaling may provide novel therapeutic targets for the treatment of PDAC.

Molecular pathogenesis of pancreatic ductal adenocarcinoma: Impact of passenger strand of pre-miR-148a on gene regulation.

We previously used RNA sequencing to establish the microRNA (miRNA) expression signature of pancreatic ductal adenocarcinoma (PDAC). We found that both strands of pre-miR-148a (miR-148a-5p: the passenger strand and miR-148a-3p: the guide strand) were downregulated in cancer tissues. Ectopic expression of miR-148a-5p and miR-148a-3p significantly inhibited cancer cell migration and invasion, indicating that both strands of pre-miR-148a had tumor-suppressive roles in PDAC cells. In silico database and genome-wide gene expression analyses identified a total of 15 genes that were putative targets regulated by these miRNAs. High expression of miR-148a-5p targets (PHLDA2, LPCAT2 and AP1S3) and miR-148a-3p targets (SMA, ENDOD1 and UHMK1) was associated with poor prognosis of patients with PDAC. Moreover, knockdown of PHLDA2 expression inhibited cancer cell aggressiveness, suggesting PHLDA2 acted as an oncogene in PDAC cells. Involvement of the passenger strand of pre-miR-148a (miR-148-5p) is a new concept in cancer research. Novel approaches that identify tumor-suppressive miRNA regulatory networks in lethal PDAC might provide new prognostic markers and therapeutic targets for this disease.

[A Case of Fournier's Gangrene Due to Perforation of Lower Rectal Cancer during Chemotherapy].

Fournier's gangrene is a rapidly progressing bacterial infection, involving the subcutaneous and deep fascia. Although intestinal perforation after treatment with bevacizumab is well known, Fournier's gangrene rarely occurs during chemotherapy. A 73-year-old man with unresectable rectal cancer during chemotherapy involving the mFOLFOX6 plus bevacizumab regimen had a consciousness disorder and was admitted to our hospital on emergency. Computed tomography scans indicated a necrotizing soft tissue infection with large amounts of pneumoderma throughout the perineum. He was diagnosed as having Fournier's gangrene via perforation of rectal cancer, and urgent operation was performed. After debridement of the skin and soft tissue around the perineum, loop sigmoidostomy was performed. A nice granulated tissue bed over the perineum was formed via daily lavage with sarin. Although the patient was taken back to the operation theater for ileostomy, he could resume chemotherapy involving mFOLFOX6 without bevacizumab 50 days after the initial operation. It is necessary to pay attention to Fournier's gangrene via perforation during chemotherapy with bevacizumab in patients with lower rectal cancer.

Surgical treatment for the excluded bile leakage from Spiegel lobe after right hemihepatectomy: A case report.

INRODUCTION: The treatments of excluded bile duct leakage after hepatectomy are not easy and various strategies have been reported, such as surgery, ethanol or fibrin glue injection, and portal vein embolization. PRESENTATION OF CASE: A 72-year-old man with a surgical history of laparoscopic ileocecal resection for diverticular bleeding was diagnosed as having hepatocellular carcinoma. Right hemihepatectomy was performed, and computed tomography examination on postoperative day 9 showed abdominal fluid collection in the right subphrenic space. Percutaneous intra-abdominal fluid drainage was performed and it was diagnosed as bile leakage. After that it was diagnosed as excluded bile leakage from the Spiegel lobe by drip infusion cholangiographic-computed tomography and endoscopic retrograde cholangiography. To improve this clinical condition, we performed the Spiegel lobe excision on postoperative day 48. The postoperative course was uneventful and the patient was discharged. DISCUSSION: According to the postoperative examination, it appeared that the bile duct from the Spiegel lobe joined to the right main bile duct or the bile duct of the right posterior section. This bile duct anomaly was not detected preoperatively on imaging examination. It is most likely that the bile duct from the Spiegel lobe was cut when the hepatoduodenal ligament in the hepatic hilum was peeled. To prevent excluded bile leakage, the hepatoduodenal ligament should be carefully peeled and ligated instead of using energy devices. CONCLUSION: We consider that surgical treatment for postoperative excluded bile leakage is both a quick and reliable procedure in patients with acceptable liver function and anatomical subject.