Weiyan Yao

XAF1 as a prognostic biomarker and therapeutic target in pancreatic cancer

XAF1 (X chromosome‐linked inhibitor of apoptosis [XIAP]‐associated factor 1) is a novel XIAP modulator that negatively regulates the anti‐apoptotic effects of XIAP and sensitizes cells to other cell death triggers. It has been reported to be downregulated in a variety of human cancer cell lines. However, the role of XAF1 in pancreatic carcinogenesis remains unclear. In the present study, we investigated the prognostic values of XAF1 expression and its regulation in cancer cell growth and apoptosis both in vitro and in vivo. From the immunohistochemistry staining of tissue microarray, 40 of 89 (44.9%) pancreatic specimens showed low levels of XAF1 expression. Statistical analysis suggested the downregulation of XAF1 was significantly correlated with tumor staging (P = 0.047) and those patients with low XAF1 levels had shorter survival times (P = 0.0162). Multivariate analysis indicated that XAF1 expression was an independent prognostic indicator of the survival of patients with pancreatic cancer (P = 0.007). Furthermore, we found that restoration of XAF1 expression mediated by Ad5/F35 virus suppressed cell proliferation and induced cell cycle arrest and apoptosis, accompanied by the activation of caspases 3, 8, and 9 and poly(ADP‐ribose) polymerase as well as increased level of cytochrome c and Bid cleavage. Notably, XAF1 restoration robustly decreased survivin expression rather than XIAP. In addition, in vivo s.c. xenografts from Ad5/F35‐XAF1 treatment, which showed less cellular proliferation and enhanced apoptosis, were significantly smaller than those from control groups. Our findings document that XAF1 is a valuable prognostic marker in pancreatic cancer and could be a potential candidate for cancer gene therapy. (Cancer Sci 2009)

Regulation and functional role of eEF1A2 in pancreatic carcinoma.

Pancreatic cancer typically has an unfavourable prognosis due to late diagnosis and a lack of therapeutic options. Thus, it is important to better understand its pathological mechanism and to develop more effective treatments for the disease. Human chromosome 20q13 has long been suspected to harbour oncogenes involved in pancreatic cancer and other tumours. In this study, we found that eEF1A2, a gene located in 20q13, was significantly upregulated in pancreatic cancer. Little or no expression of eEF1A2 was detected in normal human pancreatic and chronic pancreatitis tissues, whereas increased eEF1A2 expression occurred in 83% of the pancreatic cancers we studied. Furthermore, using in vitro and in vivo model systems, we found that overexpression of eEF1A2 promoted cell growth, survival, and invasion in pancreatic cancer. Our data thus suggest that eEF1A2 might play an important role in pancreatic carcinogenesis, possibly by acting as a tumour oncogene.

Up-Regulation of Two Actin-Associated Proteins Prompts Pulmonary Artery Smooth Muscle Cell Migration under Hypoxia

Hypoxia stimulates the migration of pulmonary artery smooth muscle cells (PASMCs), which contributes to the pathogenesis of pulmonary vessel structural remodeling in hypoxic pulmonary hypertension (HPH). In the present study, we found, using a proteomics-based method, that gelsolin-like actin-capping protein (CapG) and transgelin were preferentially expressed in human (h)PAMSCs under hypoxia compared with normoxia. These two actin-associated proteins, modulate a variety of physiologic processes, including motility of cells, by interacting differently with the actin cytoskeleton. Our study showed that these two genes were up-regulated at both mRNA and protein levels under hypoxia in hPASMCs. As a key transcriptional regulation factor under hypoxia, hypoxia-inducible factor 1alpha (HIF-1alpha) up-regulated CapG protein expression under normoxia, and knockdown of HIF-1alpha expression in hPASMCs also inhibited hypoxia induced CapG up-regulation. However, HIF-1alpha could not regulate transgelin expression. Reduction of CapG or transgelin expression in hPASMCs by RNA interference was accompanied by significantly impaired migration ability in vitro, especially under hypoxia. Our study demonstrates that CapG and transgelin were preferentially expressed in hPAMSCs under hypoxia compared with normoxia. Hypoxia stimulates expression of these two actin-associated proteins via HIF-1alpha-dependent and -independent pathways, respectively. The up-regulation of these two proteins may contribute to the increased motility of hPASMCs under hypoxia. These findings may contribute to the understanding of the pathogenesis of HPH.

Upregulation of REG Iα accelerates tumor progression in pancreatic cancer with diabetes

Diabetes is now generally accepted as a crucial event in the process of pancreatic cancer (PaC). However, molecular mechanisms underlying the relationship between diabetes and PaC are not fully understood. Regenerating gene (REG) Iα is a growth factor affecting pancreatic islet beta cells, and it has been shown to be involved in the carcinogenesis in gastrointestinal tract. It is rational to speculate that REG Iα plays a potential role in the pathogenesis of PaC with diabetes. The aim of this study was to evaluate the REG Iα protein expression profile in PaC with and without diabetes, and define the contribution of REG Iα on PaC development. We found that REG Iα protein preferentially expressed in cancerous tissues of PaC patients with diabetes by Western blot. REG Iα positive cancer cells in PaC with diabetes (n = 38) was significantly higher than that in subjects without diabetes (n = 42, p < 0.05) by immunohistochemical analysis. Furthermore, we found that overexpression of REG Iα protein in PaC cell lines resulted in accelerated cell proliferation and consequently tumor growth, both in vitro and in vivo. The findings suggest that REG Iα may act as one of the tumor promoter and contribute to the aggressive nature of PaC, especially in the subpopulation with diabetes. This study would shed new insights for understanding the molecular mechanisms underlying the link between diabetes and PaC.

Voltage-Gated Potassium Channels in IB4-Positive Colonic Sensory Neurons Mediate Visceral Hypersensitivity in the Rat

OBJECTIVES:Irritable bowel syndrome (IBS) is associated with a state of chronic visceral hypersensitivity, but the underlying molecular mechanisms of visceral hyperalgesia remain elusive. This study was designed to examine changes in the excitability and alterations of voltage-gated K+ currents in subpopulations of colonic dorsal root ganglion (DRG) neurons in a rat model of IBS-like visceral hypersensitivity.METHODS:The model of IBS-like visceral hypersensitivity was induced by intracolonic infusion of 0.5% acetic acid (AA) in saline from postnatal days 8 –21. Experiments were conducted when rats became adults. DRG neurons innervating the colon were identified by 1,1′-dioleoyl-3,3,3′,3-tetramethylindocarbocyanine methanesulfonate (DiI) fluorescence labeling and were immunostained for isolectin B4 (IB4) binding to classify these colonic neurons. Patch-clamp recordings were made from acutely dissociated DiI-labeled DRG neurons, and the expression of K+ channel in L6-S2 DRG was examined by reverse transcription–polymerase chain reaction (RT-PCR) and western blot.RESULTS:(1) Neonatal AA treatment induced long-lasting visceral hypersensitivity without significant inflammation but with mast cell hyperplasia. (2) Colonic DRG neurons contained IB4-positive and negative neurons with different electrophysiological properties. IB4-positive colonic neurons have longer action potentials (APs) and larger A-type K+ currents (IA) than the IB4-negative neurons, and IB4 phenotypic changes of colonic neurons were not involved in the chronic visceral hypersensitivity. (3) Neonatal AA treatment decreased IA density and changed the electrophysiological properties of IA and IK by shifting the steady-state inactivation toward a negative direction in IB4-positive colonic neurons. The excitability of these cells increased. (4) Kv4.3 was downregulated in neonatal AA-treated rats compared with control rats, which suggests a possible mechanism regarding the changes in electrical activity of DRG neurons in these rats.CONCLUSIONS:A new model for chronic visceral hypersensitivity following a diluted AA stimulus in the neonatal period is described. The hypersensitivity may be associated with mast cell hyperplasia in the colon and increased excitability of IB4-positive colonic neurons as a result of suppression of IA density and a shift in the inactivation curves of IA and IK in a hyperpolarizing direction in these cells. This study identifies for the first time a specific molecular mechanism in subpopulations of colonic DRG neurons that underlies chronic visceral hypersensitivity.

Role of voltage gated Ca2+ channels in rat visceral hypersensitivity change induced by 2,4,6-trinitrobenzene sulfonic acid

BackgroundVisceral pain is common symptom involved in many gastrointestinal disorders such as inflammatory bowel disease. The underlying molecular mechanisms remain elusive. We investigated the molecular mechanisms and the role for voltage gated calcium channel (VGCC) in the pathogenesis in a rat model of 2,4,6-trinitrobenzenesulfonic acid (TNBS) induced visceral inflammatory hypersensitivity.ResultsUsing Agilent cDNA arrays, we found 172 genes changed significantly in dorsal root ganglia (DRG) of TNBS treated rats. Among these changed genes, Cav1.2 and Cav2.3 were significantly up-regulated. Then the RT-PCR and Western blot further confirmed the up-regulation of Cav1.2 and Cav2.3. The whole cell patch clamp recording of acutely dissociated colonic specific DRG neurons showed that the peak IBa density was significantly increased in colonic neurons of TNBS treated rats compared with control rats (−127.82 ± 20.82 pA/pF Vs −91.67 ± 19.02 pA/pF, n = 9, *P < 0.05). To distinguish the different type of calcium currents with the corresponding selective channel blockers, we found that L-type (−38.56 ± 3.97 pA/pF Vs −25.75 ± 3.35 pA/pF, n = 9, * P < 0.05) and R-type (−13.31 ± 1.36 pA/pF Vs −8.60 ± 1.25 pA/pF, n = 9, * P < 0.05) calcium current density were significantly increased in colonic DRG neurons of TNBS treated rats compared with control rats. In addition, pharmacological blockade with L-type antagonist (nimodipine) and R-type antagonist (SNX-482) with intrathecal injection attenuates visceral pain in TNBS induced inflammatory visceral hypersensitivity.ConclusionCav1.2 and Cav2.3 in colonic primary sensory neurons play an important role in visceral inflammatory hyperalgesia, which maybe the potential therapeutic targets.

Thymosin alpha 1 improves severe acute pancreatitis in rats via regulation of peripheral T cell number and cytokine serum level

Aim:  The aim of this study was to investigate the effect of thymosin alpha 1 (TA1) on severe acute pancreatitis (SAP) in rats.

Upregulation of transgelin is an independent factor predictive of poor prognosis in patients with advanced pancreatic cancer

Transgelin is a known actin‐binding protein, which plays a role in regulating the functions of smooth muscle cells or fibroblasts. Recent evidence indicates that transgelin is involved in diverse human cancers, yet its role in pancreatic cancer remains unclear. We therefore evaluated the expression characteristics and function of transgelin in pancreatic cancer. Immunohistochemical analysis of benign (n = 30 patients) and malignant (n = 114 patients) pancreatic ductal cells showed significantly higher transgelin staining in malignant cells. Lymph node metastasis (P = 0.026) and diabetes (P = 0.041) were shown to significantly correlate with transgelin protein expression. Patients with high transgelin expression showed a shorter 5‐year overall survival and a lower tumor‐specific survival than those with low transgelin expression. Multivariate analysis revealed that transgelin was an independent factor affecting pancreatic tumor‐specific survival (P = 0.025). In vitro, RNA interference‐mediated transgelin knockdown resulted in inhibition of pancreatic cancer cell proliferation, migration and invasion. Depletion of transgelin expression could suppress pancreatic tumorigenicity and tumor growth in vivo, and produce enhanced cytotoxic effects of gemcitabine on pancreatic cancer cells both in vitro and in vivo. Our results indicate that transgelin plays a promoting role in tumor progression, and appears to be a novel prognostic marker for advanced pancreatic cancer.

Angiotensin-converting enzyme 2 acts as a potential molecular target for pancreatic cancer therapy

Angiotensin-converting enzyme 2 (ACE2) is a novel component of the renin-angiotensin system that could counterbalance the growth-promoting function of angiotensin-converting enzyme (ACE). Our previous results have shown that ACE2 is lowly expressed in pancreas, and widely down-regulated in pancreatic cancer tissues and cells. In the present study, we investigated the effect of restoration of ACE2 expression on the growth of pancreatic cancer. We found that restoration of ACE2 protein suppressed cell proliferation, motility and increased the sensitivity to hypoxia induced injury in BxPC3 and SW1990 cell lines. Stably transfected cells overexpressing ACE2 exhibited decreased tumorigenicity and delayed tumor growth, both in vitro and in vivo. In addition, restoration of ACE2 expression mediated by adenovirus vector significantly inhibited the established tumor growth, strongly enhanced the anti-tumor activity of gemcitabine in a pancreatic cancer xenograft model in vivo, and significantly prolonged the survival time of animals bearing tumor xenografts. These results provide evidence that ACE2 plays a pivotal role in the development of pancreatic cancer, and suggest that ACE2 is a promising candidate for pancreatic cancer treatment.

Idiopathic mesenteric phlebosclerosis associated with long-term use of medical liquor:Two case reports and literature review

A 62-year-old woman was admitted to our hospital in 2011 because of recurrent abdominal pain, nausea and constipation for six months. Computed tomography enterography (CTE) showed tortuous thread-like calcifications in the ileocolic vein and right colic vein, while colonoscopy revealed purple-blue mucosa extending from the cecum to the splenic flexure. Based on the results of these tests, the patient was diagnosed with idiopathic mesenteric phlebosclerosis (IMP). She had a history of Chinese medical liquor intake for one and a half years and her symptoms subsided after conservative treatment. In 2013, a 63-year-old male patient who presented with recurrent lower right abdominal pain, bloating, melena and diarrhea for fifteen months was admitted to our institution. Colonoscopy and CTE led to the diagnosis of IMP. He also used Chinese medical liquor for approximately 12 years. The patient underwent total colectomy and the postoperative course was uneventful. We searched for previously published reports on similar cases and analyzed the clinical data of 50 cases identified in PubMed. As some of these patients admitted use of Chinese medicines, we hypothesize that Chinese medicines may play a role in the pathogenesis of IMP.