Yun Cui

Roles of STAT3 and ZEB1 Proteins in E-cadherin Down-regulation and Human Colorectal Cancer Epithelial-Mesenchymal Transition

Background: Colorectal cancer (CRC) to metastatic disease may involve the epithelial-mesenchymal transition (EMT). Results: STAT3 may regulate N-cadherin, vimentin, and ZEB1 expressions. STAT3-induced cell invasion and down-regulation of E-cadherin may depend on ZEB1. Conclusion: STAT3 may mediate CRC EMT progression and ZEB1 expression. Activation of STAT3 and ZEB1 proteins may contribute to worse prognosis in CRC patients. Significance: Our data may provide potential targets to prevent and/or treat CRC invasion. The progression of colorectal carcinoma (CRC) to invasive and metastatic disease may involve localized occurrences of epithelial-mesenchymal transition (EMT). However, mechanisms of the EMT process in CRC progression are not fully understood. We previously showed that knockdown of signal transducer and activator of transcription 3 (STAT3) up-regulated E-cadherin (a key component in EMT progression) in CRC. In this study, we examined the roles of STAT3 in CRC EMT and ZEB1, an EMT inducer, in STAT3-induced down-regulation of E-cadherin. Knockdown of STAT3 significantly increased E-cadherin and decreased N-cadherin and vimentin expressions in highly invasive LoVo CRC cells. Meanwhile, overexpression of STAT3 significantly reduced E-cadherin and enhanced N-cadherin and vimentin expressions in weakly invasive SW1116 CRC cells. Activation of STAT3 significantly increased CRC cell invasiveness and resistance to apoptosis. Knockdown of STAT3 dramatically enhanced chemosensitivity of CRC cells to fluorouracil. STAT3 regulated ZEB1 expression in CRC cells, and the STAT3-induced decrease in E-cadherin and cell invasion depended on activation of ZEB1 in CRC cells. Additionally, pSTAT3Tyr-705 and ZEB1 expressions were significantly correlated with TNM (tumor, lymph node, and metastasis stages) (p < 0.01). In conclusion, STAT3 may directly mediate EMT progression and regulate ZEB1 expression in CRC. ZEB1 may participate in STAT3-induced cell invasion and E-cadherin down-regulation in CRC cells. The expressions of pSTAT3Tyr-705 and ZEB1 may be positively associated with CRC metastasis. Our data may provide potential targets to prevent and/or treat CRC invasion and metastasis.

MiR-29a Inhibits Cell Proliferation and Induces Cell Cycle Arrest through the Downregulation of p42.3 in Human Gastric Cancer

As a newly identified and characterized gene, p42.3 is associated with cell proliferation and tumorigenicity. The expression of p42.3 is upregulated in human gastric cancer (GC), but its underlying mechanisms of action are not well understood. MicroRNAs (miRNAs) are known to play vital regulatory roles in many cellular processes. Here we utilized bioinformatics and experimental approaches to investigate the regulatory relationship between miRNAs and the p42.3 gene. We showed that miR-29a could repress p42.3 expression at both the mRNA and protein levels via directly binding to its 3’UTR. Furthermore, an inverse relationship was observed between miR-29a and p42.3 expression in gastric cancer cell lines and GC tissue samples, especially in cases where p42.3 was downregulated. Taken together, we have elucidated previously unrecognized roles of miR-29a and indicated that miR-29a may function, at least partially, by targeting the p42.3 gene in human GC.

Biological Functions of Cytokeratin 18 in Cancer

The structural proteins cytokeratin 18 (CK18) and its coexpressed complementary partner CK8 are expressed in a variety of adult epithelial organs and may play a role in carcinogenesis. In this study, we focused on the biological functions of CK18, which is thought to modulate intracellular signaling and operates in conjunction with various related proteins. CK18 may affect carcinogenesis through several signaling pathways, including the phosphoinositide 3-kinase (PI3K)/Akt, Wnt, and extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) signaling pathways. CK18 acts as an identical target of Akt in the PI3K/Akt pathway and of ERK1/2 in the ERK MAPK pathway, and regulation of CK18 by Wnt is involved in Akt activation. Finally, we discuss the importance of gaining a more complete understanding of the expression of CK18 during carcinogenesis, and suggest potential clinical applications of that understanding. Mol Cancer Res; 10(4); 485–93. ©2012 AACR.

Bidirectional regulation between WDR83 and its natural antisense transcript DHPS in gastric cancer

Natural antisense transcripts (NATs) exist ubiquitously in mammalian genomes and play roles in the regulation of gene expression. However, both the existence of bidirectional antisense RNA regulation and the possibility of protein-coding genes that function as antisense RNAs remain speculative. Here, we found that the protein-coding gene, deoxyhypusine synthase (DHPS), as the NAT of WDR83, concordantly regulated the expression of WDR83 mRNA and protein. Conversely, WDR83 also regulated DHPS by antisense pairing in a concordant manner. WDR83 and DHPS were capable of forming an RNA duplex at overlapping 3′ untranslated regions and this duplex increased their mutual stability, which was required for the bidirectional regulation. As a pair of protein-coding cis-sense/antisense transcripts, WDR83 and DHPS were upregulated simultaneously and correlated positively in gastric cancer (GC), driving GC pathophysiology by promoting cell proliferation. Furthermore, the positive relationship between WDR83 and DHPS was also observed in other cancers. The bidirectional regulatory relationship between WDR83 and DHPS not only enriches our understanding of antisense regulation, but also provides a more complete understanding of their functions in tumor development.

Role of STAT3 and vitamin D receptor in EZH2-mediated invasion of human colorectal cancer.

The above article from The Journal of Pathology, published online on 7 June 2013 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors, the journal Editor‐in‐Chief, Prof. C. Simon Herrington, and John Wiley & Sons Limited. Some sequences in Figure 6C were mistakenly identified, with consequent errors in the description of this figure and in the Materials and Methods section. Additionally, in Figures 5C, 5F and 7 some images were duplicated and erroneously presented as unique. The authors apologise to readers of the journal.

TNF-α-induced CXCL8 production by A549 cells: Involvement of the non-neuronal cholinergic system

It was recently suggested that the non-neuronal cholinergic system has a regulatory role in pulmonary inflammation. We investigated this systems involvement in the control of cytokine production by the A549 human alveolar epithelial cell line. CXCL8 and acetylcholine (ACh) concentrations were measured using ELISA and LC-MS/MS, respectively. The mRNA expression of muscarinic receptor (MR) subtypes was determined using RT-PCR. In A549 cells, TNF-α increased the release of CXCL8 and ACh and the expression of the subtype 3 MR (M3R). Furthermore, TNF-α-induced CXCL8 secretion was (i) inhibited by the MR antagonist tiotropium and the M3R antagonist 4-DAMP and (ii) enhanced by the M1/M3R agonist pilocarpine and the cholinesterase inhibitor physostigmine. Taken as a whole, these results suggest that ACh release by A549 cells enhances TNF-α-induced CXCL8 secretion through activation of the M3R. Western blot analysis revealed that pilocarpine and physostigmine enhanced the TNF-α-induced phosphorylation of ERK1/2 and p38 MAPK and the degradation of IκBα. Inhibition of these pathways with specific inhibitors abrogated the pilocarpine-induced CXCL8 release. Our results suggest that the TNF-α-induced secretion of CXCL8 in A549 cells is regulated by the release of ACh, the latters binding to the M3R and the downstream activation of NF-κB and the ERK1/2 and p38 MAPK signaling pathways. Our findings suggest that MR antagonists may have anti-inflammatory effects by preventing pro-inflammatory events driven by endogenous, non-neuronal ACh.

Up-regulation of KCa3.1 promotes human airway smooth muscle cell phenotypic modulation

Airway smooth muscle (ASM) cell phenotype modulation, characterized by reversible switching between contractile and proliferative phenotypes, is considered to contribute to proliferative diseases such as allergic asthma and chronic obstructive pulmonary disease (COPD). KCa3.1 has been suggested to be involved in regulating ASM cell activation, proliferation, and migration. However, little is known regarding the exact role of KCa3.1 in ASM cell phenotypic modulation. To elucidate the role of KCa3.1 in regulating ASM cell phenotypic modulation, we investigated the effects of KCa3.1 channels on ASM contractile marker protein expression, proliferation and migration of primary human bronchial smooth muscle (BSM) cells. We found that PDGF increased KCa3.1 channel expression in BSM cells with a concomitant marked decrease in the expression of contractile phenotypic marker proteins including smooth muscle myosin heavy chain (SMMHC), smooth muscle α-actin (α-SMA), myocardin and KCa1.1. These changes were significantly attenuated by the KCa3.1 blocker, TRAM-34, or gene silencing of KCa3.1. Pharmacological blockade or gene silencing of KCa3.1 also suppressed PDGF-induced human BSM cell migration and proliferation accompanied by a decrease in intracellular free Ca(2+) levels as a consequence of membrane depolarization, resulting in a reduction in cyclin D1 level and cell cycle arrest at G0-G1 phase. Additionally, PDGF-induced up-regulation of KCa3.1 and down-regulation of BSM contractile marker proteins were regulated by the ERK inhibitor U0126 and the AKT inhibitor LY294002. These findings highlight a novel role for the KCa3.1 channel in human BSM cell phenotypic modulation and provide a potential target for therapeutic intervention for proliferative airway diseases.

Rabeprazole Combined with Hydrotalcite is Effective for Patients with Bile Reflux Gastritis after Cholecystectomy

BACKGROUND Regardless of surgical technique, patients who have undergone cholecystectomy appear to be predisposed to the development of bile reflux gastritis. OBJECTIVE To assess the efficacy of rabeprazole and hydrotalcite in patients with bile reflux gastritis after cholecystectomy. METHODS Postcholecystectomy patients with bile reflux gastritis confirmed by endoscopy and 24 h gastric bilirubin monitoring were randomly assigned to one of four eight-week treatments: observation (group A), rabeprazole alone (group B), hydrotalcite alone (group C) and rabeprazole in combination with hydrotalcite (group D). Endoscopy and 24 h gastric bilirubin monitoring were repeated in all patients after treatment. Dyspeptic symptoms of abdominal pain, bloating, heartburn, bitter taste, endoscopic and histological finding, and biliary reflux were evaluated before and after treatment. RESULTS After administering medication, patient symptoms in groups B, C and D were relieved - most significantly in group D (P<0.05). There were no significant differences in endoscopic hyperemia and histological inflammation among the groups (P>0.05). However, histological activity, the number of reflux episodes and the number of reflux episodes lasting longer than 5 min were significantly decreased only in group D (P<0.05). The total per cent of bilirubin absorption (value of 0.14 units or greater) time was decreased in groups B, C and D, and most significantly in group D (P<0.05). CONCLUSION Rabeprazole combined with hydrotalcite is an effective therapeutic option in the treatment of patients with bile reflux gastritis after cholecystectomy.

Role of C9orf140 in the promotion of colorectal cancer progression and mechanisms of its upregulation via activation of STAT5, β-catenin and EZH2

C9orf140 is a newly identified and characterized gene which is associated with cell proliferation and tumorigenicity. Expression of C9orf140 is upregulated in human gastric cancer and colorectal cancer (CRC); however, little is known about its role in CRC progression. We have investigated the clinical significance, biological effects and mechanisms of C9orf140 signaling. We found that the expression of C9orf140 is dramatically increased in a subset of CRC and correlates significantly with vascular invasion and lymph node metastasis. Our finding showed that knockdown of C9orf140 significantly reduced cell proliferation and invasion in vitro and dramatically increased overall survival and decreased lung metastasis in vivo. Conversely, overexpression of C9orf140 significantly increased lung metastasis and shortened overall survival when compared with control tumors. C9orf140-induced CRC cell invasion may depend on promoting the epithelial-mesenchymal transition progression. STAT5 may directly interact with the enhancer of zeste homolog 2 (EZH2) and β-catenin to enhance C9orf140 gene transactivation. Furthermore, C9orf140 may participate in cell invasion which is induced by STAT5, EZH2 or β-catenin activation. We describe the role of C9orf140 in CRC progression and find that C9orf140 overexpression may be regulated by STAT5, EZH2 and β-catenin interaction.

Fecal Clostridium symbiosum for Noninvasive Detection of Early and Advanced Colorectal Cancer: Test and Validation Studies

Objective Current non-invasive early detection of colorectal cancer (CRC) requires improvement. We aimed to identified a fecal Clostridium symbiosum-based biomarker for early and advanced colorectal cancer detection. Design In the test stage, the relative abundance of Clostridium symbiosum (C. symbiosum) was measured by qPCR in 781 cases including 242 controls, 212 colorectal adenoma (CRA) patients, 109 early CRC (tumor restricted to the submucosa) patients, 218 advanced CRC patients. The prediction accuracy was compared to Fusobacterium nucleatum (F. nucleatum), fecal immunochemical test (FIT) and CEA (carcinoembryonic antigen) and validated in an independent cohort of 256 subjects. Current status of the trial:ongoing/still enrolling. Primary endpoint:June, 2017 (Clinicaltrials.gov Identifier NCT02845973). Results Significant stepwise increase of C. symbiosum abundance was found in CRA, early CRC and advanced CRC (P < 0.01). C. symbiosum outperformed all the other markers in early CRC prediction performance. The combination of C. symbiosum and FIT achieved better performance (0.803 for test cohort and 0.707 for validation cohort). For overall discrimination of CRCs, the combination of all above markers achieved the performance of 0.876. Conclusions Fecal C. symbiosum is a promising biomarker for early and noninvasive detection of colorectal cancer, being more effective than F. nucleatum, FIT and CEA. Combining C. symbiosum and FIT or CEA may improve the diagnosis power.