LncRNA-PVT1 promotes pancreatic cancer cells proliferation and migration through acting as a molecular sponge to regulate miR-448.

The identification and characterization of long non-coding RNAs (lncRNAs) in diverse biological process has currently developed rapidly. LncRNA-PVT1, located adjacent to the MYC locus on chromosomal region 8q24, has been reported to be associated with many biological processes. However, the function and mechanism of PVT1 in pancreatic carcinoma (PC) is poorly understood. In this present study, we first measured the level of PVT1 in the PC cell lines and tissues by quantitative real-time PCR (qRT-PCR), and then employed loss-of-function and gain-of-function approaches to explore the association between PVT1 expression levels and PC cell proliferation/migration ability. Furthermore, bioinformatics analysis was utilized to show that PVT1 contains binding site for miR-448 and an inverse correlation between PVT1 and miR-448 was obtained in PC specimens. Additionally, dual luciferase reporter assay, RNA-binding protein immunoprecipitation (RIP) and applied biotin-avidin pulldown system were applied to further confirm that PVT1 directly bind with microRNA binding site harboring in the PVT1 sequence. Then, SERBP1 was identified as a target of miR-448 according to the gene expression array analysis of PC clinical samples. Together, we revealed that PVT1 functions as an endogenous "sponge" by competing for miR-448 binding to regulate the miRNA target SERBP1 and, therefore, promotes the proliferation and migration of PC cells.

Mechanism Comparison of Gemcitabine and Dasatinib-Resistant Pancreatic Cancer by Integrating mRNA and miRNA Expression Profiles.

BACKGROUND: Pancreatic cancer is one of the most lethal cancers with limited treatment options. Gemcitabine has been the standard drug for patients with advanced pancreatic cancer. Dasatinib is a competitive inhibitor of Src kinase, which has shown promise in treatment of pancreatic cancer. Several studies have revealed the drug resistant mechanism of gemcitabine or dasatinib in human cancers; however, few reports focused on the different mechanisms of gemcitabine and dasatinib resistance in pancreatic cancer. Here, we integrate mRNA and miRNA expression profiles to achieve it. METHODS: Two mRNA expression profiles were downloaded from GEO database. The differentially expressed genes (DEGs) were identified with |fold change| ≥ 2 and p-value ≤ 0.05. Further function of the DEGs were annotated with GO and KEGG pathway enrichment. Finally, the mRNA-miRNA interaction networks were constructed to explore the molecular mechanism. RESULTS: Results showed that 116 and 238 DEGs were detected in gemcitabine-resistant cell lines and dasatinib-resistant cell lines respectively. Meanwhile, 4 common DEGs were identified in both resistant cell lines, which can clearly divide all cell lines into different sub-groups. KEGG pathway enrichment analysis displayed that the DEGs of both gemcitabine-resistant cell lines and dasatinib-resistant cell lines can map to drug metabolism-cytochrome P450 and metabolism of xenobiotics by cytochrome P450, while DEGs of gemcitabine-resistant cell lines can also map to several metabolism related pathways and dasatinib-resistant cell lines for several cancer related pathways. GO annotation analysis showed that the DEGs of gemcitabine-resistant cell lines and dasatinib-resistant cell lines can also be categorized into drug metabolism. Additionally, the miRNA-mRNA regulation network of gemcitabine-resistant cell lines revealed 16 DEGs were regulated by 6 miRNAs, indicating that these miRNAs may play a key role in gemcitabine treatment of pancreatic cancer. CONCLUSIONS: The difference of gemcitabine resistance in pancreatic cancer were explored by mechanism comparison via the mRNA and miRNA expression profile. These findings support strategies to target molecules and relevant pathways for improving the efficacy of chemotherapy in pancreatic cancer patients.

The Lncrna-TUG1/EZH2 Axis Promotes Pancreatic Cancer Cell Proliferation, Migration and EMT Phenotype Formation Through Sponging Mir-382.

BACKGROUND/AIMS: Pancreatic carcinoma (PC) is the one of the most common and malignant cancers worldwide. LncRNA taurine upregulated gene 1 (TUG1) was initially identified as a transcript upregulated by taurine, and the abnormal expression of TUG1 has been reported in many cancers. However, the biological role and molecular mechanism of TUG1 in PC still needs further investigation. METHODS: Quantitative real-time PCR (qRT-PCR) was performed to measure the expression of TUG1 in PC cell lines and tissues. MTT and colony formation assays were used to measure the effect of TUG1 on cell proliferation. A wound healing assay, transwell assay and western blot assay were employed to determine the effect of TUG1 on cell migration and the epithelial mesenchymal transition (EMT) phenotype. RNA-binding protein immunoprecipitation (RIP) and a biotin-avidin pulldown system were performed to confirm the interaction between miR-328 and TUG1. A gene expression array analysis using clinical samples and RT-qPCR suggested that enhancer of zeste homolog 2 (EZH2) was a target of miR-382 in PC. RESULTS: In this study, we reported that TUG1 was overexpressed in PC tissues and cell lines, and high expression of TUG1 predicted poor prognosis. Further experiments revealed that overexpressed TUG1 promoted cell proliferation, migration and contributed to EMT formation, whereas silenced TUG1 led to opposing results. Additionally, luciferase reporter assays, an RIP assay and an RNA-pulldown assay demonstrated that TUG1 could competitively sponge miR-382 and thereby regulate EZH2. CONCLUSION: Collectively, these findings revealed that TUG1 functions as an oncogenic lncRNA that promotes tumor progression, at least partially, by functioning as an endogenous 'sponge' and competing for miR-382 binding to the miRNA target EZH2.

Clinicopathological significance and potential drug target of O6-methylguanine-DNA methyltransferase in colorectal cancer: a meta-analysis.

Emerging evidence indicates that O(6)-methylguanine-DNA methyltransferase (MGMT) is a candidate for tumor suppression in several types of human tumors including colorectal cancer (CRC). However, the correlation between MGMT hypermethylation and clinicopathological characteristics of CRC remains unclear. In this study, we conducted a systematic review and meta-analysis to quantitatively evaluate the effects of MGMT hypermethylation on the incidence of CRC and clinicopathological characteristics. A comprehensive literature search was done from Web of Science, the Cochrane Library Database, PubMed, EMBASE, CINAHL, and the Chinese Biomedical Database for related research publications written in English and Chinese. Methodological quality of the studies was also evaluated. Analyses of pooled data were performed with Review Manager 5.2. Odds ratio (OR) and hazard ratio (HR) were calculated and summarized, respectively. Final analysis from 28 eligible studies was performed. MGMT hypermethylation is found to be significantly higher in CRC than in normal colorectal mucosa, the pooled OR from 13 studies including 1085 CRC and 899 normal colorectal mucosa, OR = 6.04, 95 % confidence interval (CI) = 4.69-7.77, p < 0.00001. MGMT hypermethylation is also significantly higher in colorectal adenoma than in normal colorectal mucosa, but it is significantly less compared to that in CRC patients. Interestingly, MGMT hypermethylation is correlated with sex status and is significantly higher in female than in male. MGMT hypermethylation is also associated with high levels of microsatellite instability (MSI). The pooled HR for overall survival (OS) shows that MGMT hypermethylation is not associated with worse survival in CRC patients. The results of this meta-analysis suggest that MGMT hypermethylation is associated with an increased risk and high levels of MSI and may play an important role in CRC initiation. However, MGMT hypermethylation may play an important role in the early stage of CRC progression and development, as well as having limited value in prediction of prognosis in CRC patients. We also discussed that MGMT may serve as a potential drug target of CRC.

CSTF2T facilitates pancreatic adenocarcinoma growth and metastasis by elevating H3K4Me1 methylation of CALB2 via ASH2L.

Pancreatic adenocarcinoma (PAAD) is a major cause of mortality related to cancer worldwide. This paper dissected the functions of the CSTF2T/ASH2L/CALB2 axis in PAAD progression. CALB2 expression was assessed in PAAD tissues and cells using RT-qPCR and western blot. Subsequent to gain- and loss-of-function experiments in PAAD cells, cell apoptosis, invasion, proliferation, and migration were examined using flow cytometry, Transwell, CCK-8, and Scratch assays. Additionally, the expression of proliferation markers and apoptotic and metastasis- and invasion-related proteins was measured using western blot. The relationship among CALB2, KMT2D, ASH2L, H3K4Me1, and CSTF2T was evaluated using ChIP, RNA pull-down, RIP, and Co-IP assays. A nude mouse transplantation tumor model was established, with observation of tumor growth and metastasis. CALB2 expression was high in PAAD tissues and cells. Mechanistically, KMT2D was enriched in the CALB2 promoter, and CSTF2T bound to and upregulated ASH2L as a RNA binding protein, which was a core component of the KMT2D complex to enhance CALB2 expression through H3K4Me1 upregulation. CALB2 knockdown diminished the viability, invasion, and migration but elevated the apoptosis of PAAD cells. Likewise, CSTF2T knockdown suppressed the growth and metastasis of PAAD cells and transplanted tumors in nude mice, which was counteracted by further CALB2 overexpression. CSTF2T knockdown blocked the ASH2L/CALB2 axis to protect against PAAD growth and metastasis.

Low SP1 SUMOylation-dependent SNHG17 upregulation promotes drug resistance of gastric cancer through impairing hsa-miR-23b-3p-induced Notch2 inhibition.

OBJECTIVE: Specificity protein 1 (SP1), a transcription factor mediated by SUMOylation modifiers, is upregulated in gastric cancer (GC) and shares negative correlation with patient prognosis. Here, we paid main attention to the role of SP1 SUMOylation in the drug resistance of GC cells and the possible long non-coding RNA (lncRNA) SNHG17/microRNA-23b-3p (miR-23b-3p)/Notch2 network engaged in this process. METHODS: Tumor tissues and non-tumor tissues were isolated from GC patients who received treatment with capecitabine and cisplatin (DDP). Co-immunoprecipitation was utilized to detect the SUMOylation level of SP1. Using gain- and loss-of-function approaches, we assessed the impacts of SNHG17/miR-23b-3p/Notch2 on sensitivity of DDP-resistant GC cells in vitro and in vivo. A series of assays such as luciferase activity detection and RNA pull-down were conducted for mechanistic exploration. RESULTS: SP1 expression was increased due to low SP1 SUMOylation level in the recurrent GC tissues. This increase led to upregulated SNHG17 expression and SP1 binding sites existed in the SNHG17 promoter. In addition, SNHG17 could bind to miR-23b-3p while miR-23b-3p targeted Notch2. Loss of SNHG17 reduced the resistance of DDP-resistant GC cells to DDP, which was achieved through miR-23b-3p-dependent Notch2 inhibition. Finally, SP1 silencing attenuated the resistance of GC to DDP in mice. CONCLUSION: Low SP1 SUMOylation induces SNHG17 upregulation and blocks miR-23b-3p-induced Notch2 inhibition, contributing to the resistance of GC to DDP. This study may aid in the development of therapeutic targets overcoming the chemoresistance of GC.

Overexpression of Dermokine-α enhances the proliferation and epithelial-mesenchymal transition of pancreatic tumor cells.

Pancreatic cancer is a prevalent malignancy of the digestive system and a major cause of cancer-associated deaths. Previous studies have shown that mutation in the dermokine-ß (DMKN-ß) gene causes pancreatic and colorectal cancer. The role of the carboxy-terminal domain of DMKN-ß and dermokine-α (DMKN-α) genes in cancer tumorigenesis. Herein, the role of DMKN-α in pancreatic cancer (PC) tumorigenesis and the mechanisms underlying this process were investigated. Differentially expressed genes between PC and matched normal cells were identified through RNA-seq analysis, and the corresponding protein expression levels were verified using Western blot analysis. In vivo tumor formation experiment was also performed in nude mice. We found that the DMKN-α gene was overexpressed in cancerous pancreatic cell lines compared to normal pancreatic cell lines. CCK-8, colony formation, RTCA test, wound healing, as well as transwell test showed that the overexpression of DMKN-α enhanced the proliferation, migration, invasion, and EMT of PC cells. In vivo assays confirmed that DMKN-α promotes tumorigenesis. The findings of this study show that DMKN-α is a potential oncogene for pancreatic cancer.

Sitagliptin activates the p62-Keap1-Nrf2 signalling pathway to alleviate oxidative stress and excessive autophagy in severe acute pancreatitis-related acute lung injury.

Acute lung injury (ALI) is a complication of severe acute pancreatitis (SAP). Sitagliptin (SIT) is a DPP4 inhibitor that exerts anti-inflammatory and antioxidant effects; however, its mechanism of action in SAP-ALI remains unclear. In this study, we investigated the effects of SIT on SAP-ALI and the specific pathways involved in SAP-induced lung inflammation, including oxidative stress, autophagy, and p62-Kelch-like ECH-associated protein 1 (Keap1)-NF-E2-related factor 2 (Nrf2) signalling pathways. Nrf2 knockout (Nrf2-/-) and wild-type (WT) mice were pre-treated with SIT (100 mg/kg), followed by caerulein and lipopolysaccharide (LPS) administration to induce pancreatic and lung injury. BEAS-2B cells were transfected with siRNA-Nrf2 and treated with LPS, and the changes in inflammation, reactive oxygen species (ROS) levels, and autophagy were measured. SIT reduced histological damage, oedema, and myeloperoxidase activity in the lung, decreased the expression of pro-inflammatory cytokines, and inhibited excessive autophagy and ROS production via the activation of the p62-Keap1-Nrf2 signalling pathway and promotion of the nuclear translocation of Nrf2. In Nrf2-knockout mice, the anti-inflammatory effect of SIT was reduced, resulting in ROS accumulation and excessive autophagy. In BEAS-2B cells, LPS induced ROS production and activated autophagy, further enhanced by Nrf2 knockdown. This study demonstrates that SIT reduces SAP-ALI-associated oxidative stress and excessive autophagy through the p62-Keap1-Nrf2 signalling pathway and nuclear translocation of Nrf2, suggesting its therapeutic potential in SAP-ALI.

Isocorydine suppresses doxorubicin-induced epithelial-mesenchymal transition via inhibition of ERK signaling pathways in hepatocellular carcinoma.

Doxorubicin (DOX) is a conventional and effective chemotherapeutic used in the treatment of hepatocellular carcinoma (HCC). However, doxorubicin administration may induce EMT, which results in the development of chemoresistance in HCC. Recent studies report that Isocorydine (ICD) selectively inhibits human cancer stem cells (CSCs), which have an important role in the development of chemoresistance. In this study, we observed that ICD co-administration enhanced DOX cytotoxicity in HCC cells, enabling the inhibition of DOX-induced epithelial-mesenchymal transition (EMT). Microarray data analysis revealed substantially decreased ERK signaling after ICD treatment. Additionally, we observed decreased IC50 for DOX upon ERK knockdown. Finally, we confirmed the enhanced efficacy of treatment with a combination of DOX and ICD in xenograft models. Collectively, the present study unveils the benefit of using DOX in combination with ICD for chemotherapy against HCC, revealing a novel potential anti-cancer strategy.

The C825T Polymorphism of the G-Protein ß3 Gene as a Risk Factor for Functional Dyspepsia: A Meta-Analysis.

Background. Functional dyspepsia (FD) is a functional upper gastrointestinal disorder with significant morbidity and medical costs. Previous studies investigated the association of G-protein ß3 (GNB3) genetic polymorphisms with FD but with inconsistent results. Therefore, we performed a meta-analysis to derive a precise estimation of the relationship between GNB3 polymorphisms and FD. Methods. We searched different databases including PubMed, EMBASE, CNKI, and the Ovid Library to gather eligible studies on GNB3 polymorphisms and FD. The association was assessed by the odds ratio (OR) with 95% confidence intervals (CI). Results. We identified 12 studies with 1109 cases and 2853 controls for the analysis. We found no associations of GNB3 C825T polymorphism with FD in the overall population (T versus C, OR = 1.06, 95% CI: 0.96-1.18, P = 0.26; TT versus CC + CT, OR = 1.16, 95% CI: 0.97-1.39, P = 0.11; TT + CT versus CC, OR = 1.01, 95% CI: 0.77-1.31, P = 0.96; TT versus CC, OR = 1.15, 95% CI: 0.93-1.44, P = 0.20). Subgroup analyses by genotyping method indicated that the magnitude of association was strengthened for additive model (OR = 1.15, 95% CI: 1.07-2.24, P = 0.02). Sensitivity analysis did not reveal significant associations under all models. Conclusions. This meta-analysis demonstrates that GNB3 C825T polymorphism may not be a risk factor for FD.

Interleukin-32α inactivates JAK2/STAT3 signaling and reverses interleukin-6-induced epithelial-mesenchymal transition, invasion, and metastasis in pancreatic cancer cells.

Interleukin (IL)-32 is a newly discovered cytokine that has multifaceted roles in inflammatory bowel disease, cancer, and autoimmune diseases and participates in cell apoptosis, cancer cell growth inhibition, accentuation of inflammation, and angiogenesis. Here, we investigated the potential effects of IL-32α on epithelial-mesenchymal transition, metastasis, and invasion, and the JAK2/STAT3 signaling pathway in pancreatic cancer cells. The human pancreatic cancer cell lines PANC-1 and SW1990 were used. Epithelial-mesenchymal transition-related markers, including E-cadherin, N-cadherin, Vimentin, Snail, and Zeb1, as well as extracellular matrix metalloproteinases (MMPs), including MMP2, MMP7, and MMP9, were detected by immunofluorescence, Western blotting, and real-time polymerase chain reaction. The activation of JAK2/STAT3 signaling proteins was detected by Western blotting. Wound healing assays, real-time polymerase chain reaction, and Western blotting were performed to assess cell migration and invasion. The effects of IL-32α on the IL-6-induced activation of JAK2/STAT3 were also evaluated. In vitro, we found that IL-32α inhibits the expressions of the related markers N-cadherin, Vimentin, Snail, and Zeb1, as well as JAK2/STAT3 proteins, in a dose-dependent manner in pancreatic cancer cell lines. Furthermore, E-cadherin expression was increased significantly after IL-32α treatment. IL-32α downregulated the expression of MMPs, including MMP2, MMP7, and MMP9, and decreased wound healing in pancreatic cancer cells. These consistent changes were also found in IL-6-induced pancreatic cancer cells following IL-32α treatment. This study showed that reversion of epithelial-mesenchymal transition, inhibition of invasiveness and metastasis, and activation of the JAK2/STAT3 signaling pathway could be achieved through the application of exogenous IL-32α.

Promotion of Metastasis-associated Gene Expression in Survived PANC-1 Cells Following Trichostatin A Treatment.

OBJECTIVES: Histone deacetylase inhibitors represent a promising class of potential anticancer agents for the treatment of human malignancies. In this study, the effects of trichostatin A (TSA) on apoptosis, metastasis-associated gene expression, and activation of the Notch pathway in human pancreatic cancer cell lines were investigated. METHODS: After treatment with TSA, cell viability and apoptosis were evaluated using the MTT [3-(4,5-dimethylthia-zol-2-yl)-2,5-diphenyltetrazolium bromide] assay, Hoechst 33258 staining, and flow cytometry. Moreover, RT-PCR and western blot analyses were performed to measure the expression levels of apoptosis-associated genes (Bcl-2, Bax, and caspase-3), metastasis-associated genes (E-cadherin, vimentin, and matrix metalloproteinases), and Notch pathway activation (Notch intracellular domain, NICD). The levels of matrix metalloproteinase 2 and NICD were also semi-quantified by immunoassay. RESULTS: Following treatment with TSA for 24 h, PANC-1, SW1990, and MIATACA-2 cells exhibited cell death. The MTT assay revealed that TSA significantly decreased cell viability in a dose-dependent manner in PANC-1 cells. The Hoechst 33258 staining and flow cytometry results evidenced a significant increase in PANC-1 cell apoptosis following TSA treatment. The expression levels of Bax and caspase-3 were increased significantly, whereas Bcl-2 was down-regulated after TSA treatment. In the PANC-1 cells that survived after TSA treatment, the expression levels of vimentin, E-cadherin, and MMP genes were altered by the promotion of potential metastasis and increased expression of NICD. CONCLUSIONS: TSA can induce apoptosis of pancreatic cancer cells. In addition, the up-regulation of metastasis-related genes and the activation of the Notch pathway in the survived PANC-1 cells may be associated with a too-low level of TSA or resistance to TSA.

Reversion of trichostatin A resistance via inhibition of the Wnt signaling pathway in human pancreatic cancer cells.

Drug resistance is a major impediment to successful chemotherapy in pancreatic cancer (PC) patients. We investigated the effect of Wnt/ß-catenin signaling inhibition by wnt-c59 on chemoresistance in a trichostatin A-resistant Panc-1 cell line (Panc-1/TSA). Panc-1/TSA cells were treated with the Wnt/ß­catenin signaling inhibitor wnt-c59 (10 µmol · l-1) and/or trichostatin A (TSA; 10 µmol · l-1) for 24 h. CCK-8 assay was utilized to analyze the interactive effect of TSA and wnt-c59 on induction of apoptosis of the Panc-1/TSA cells. Cell apoptosis was measured by flow cytometry. Real-time PCR and western blotting were used to assess Wnt/ß-catenin signaling, epithelial-mesenchymal transition (EMT) and multidrug resistance (MDR). Real-time cell analysis (RTCA) was used to detect the cell migration ability. After wnt-c59 treatment for 24 h, relative genes and transcriptional targets of Wnt/ß-catenin signaling were downregulated (P<0.05). CCK-8 assay indicated that the combination of TSA and wnt-c59 had a synergistic effect on induction of Panc-1/TSA cell apoptosis. As detected by FACS, cell apoptosis rates increased significantly (P<0.05). The results of RTCA showed that the cell indices of the control group, wnt-c59 group, TSA group and TSA+wnt-c59 combination group were 1.2842±0.0257, 1.2155±0.0282, 1.2533±0.0194 and 0.8541±0.0250, respectively. In accordance, MMP-9 protein in the wnt-c59 treatment groups was decreased compared to the non-wnt-c59 treatment groups. Meanwhile, E-cadherin protein was upregulated and vimentin protein was downregulated, both of which are characteristic markers of EMT. Chemoresistant gene MDR1 and P-glycoprotein (P-gp) in the wnt-c59 treatment groups had a reduced expression compared to the non-wnt-c59 treatment groups. This study revealed that TSA sensitivity, migration ability, and the EMT phenotype in Panc-1/TSA cells were reversed following Wnt/ß-catenin signaling inhibition.