Biological Behavior Of Pancreatic Cancer Research Articles

An amino acid metabolism-based seventeen-gene signature correlates with the clinical outcome and immune features in pancreatic cancer.

Background: Pancreatic cancer is an aggressive tumor with a low 5-year survival rate and primary resistance to most therapy. Amino acid (AA) metabolism is highly correlated with tumor growth, crucial to the aggressive biological behavior of pancreatic cancer; nevertheless, the comprehensive predictive significance of genes that regulate AA metabolism in pancreatic cancer remains unknown. Methods: The mRNA expression data downloaded from The Cancer Genome Atlas (TCGA) were derived as the training cohort, and the GSE57495 cohort from Gene Expression Omnibus (GEO) database was applied as the validation cohort. Random survival forest (RSF) and the least absolute shrinkage and selection operator (LASSO) regression analysis were employed to screen genes and construct an AA metabolism-related risk signature (AMRS). Kaplan-Meier analysis and receiver operating characteristic (ROC) curve were performed to assess the prognostic value of AMRS. We performed genomic alteration analysis and explored the difference in tumor microenvironment (TME) landscape associated with KRAS and TP53 mutation in both high- and low-AMRS groups. Subsequently, the relationships between AMRS and immunotherapy and chemotherapy sensitivity were evaluated. Results: A 17-gene AA metabolism-related risk model in the TCGA cohort was constructed according to RSF and LASSO. After stratifying patients into high- and low-AMRS groups based on the optimal cut-off value, we found that high-AMRS patients had worse overall survival (OS) in the training cohort (a median OS: 13.1months vs. 50.1 months, p < 0.0001) and validation cohort (a median OS: 16.2 vs. 30.5 months, p = 1e-04). Genetic mutation analysis revealed that KRAS and TP53 were significantly more mutated in high-AMRS group, and patients with KRAS and TP53 alterations had significantly higher risk scores than those without. Based on the analysis of TME, low-AMRS group displayed significantly higher immune score and more enrichment of T Cell CD8+ cells. In addition, high-AMRS-group exhibited higher TMB and significantly lower tumor immune dysfunction and exclusion (TIDE) score and T Cells dysfunction score, which suggested a higher sensitive to immunotherapy. Moreover, high-AMRS group was also more sensitive to paclitaxel, cisplatin, and docetaxel. Conclusion: Overall, we constructed an AA-metabolism prognostic model, which provided a powerful prognostic predictor for the clinical treatment of pancreatic cancer.

Insulin promotes the proliferation and migration of pancreatic cancer cells by up-regulating the expression of PLK1 through the PI3K/AKT pathway.

Pancreatic cancer has a particularly poor prognosis compared to other tumors. The peculiar hyperinsulin microenvironment of the pancreas is formed due to the endocrine secretion of islets in the pancreas. This study focused on the effect of insulin on the migration and proliferation of pancreatic cancer cells and its molecular mechanisms. We found that insulin promotes the proliferation and migration of pancreatic cancer cells. At the same time, it can up-regulate the expression of PLK1 in pancreatic cancer cells. Knocking down the expression of PLK1 in pancreatic cancer cells can inhibit the effect of insulin on the biological behavior of pancreatic cancer. In addition, we found that insulin activates the PI3K/AKT pathway in pancreatic cancer cells, and that inhibition of this pathway suppresses PLK1 expression. The PI3K/AKT inhibitor LY294002 inhibits the effects of insulin on the proliferation of pancreatic cancer cells. This study shows that insulin up-regulates PLK1 expression in pancreatic cancer cells via the PI3K/AKT pathway, which in this way enhances the migration and proliferation of pancreatic cancer cells. This may be one of the important reasons for the poor prognosis of pancreatic cancer.

The Role of Signaling Pathways in Pancreatic Cancer Targeted Therapy.

Signaling pathways play significant roles in the occurrence, development, and treatment of pancreatic cancer (PC). The main treatment options are surgery, chemotherapy, radiotherapy, arterial infusion chemotherapy in interventional therapy, and immunotherapy. Many studies have shown that signaling pathways perform a function in the occurrence and development of PC, for instance, phosphoinositide 3-kinase (PI3K)/AKT, nuclear factor-κB, Ras, interleukin (IL)-17B/IL-17RB, Wnt, and hepatocyte growth factor/c-MET, which play roles in the proliferation, metastasis, invasion, inhibition of apoptosis, promotion of angiogenesis, and drug resistance of PC. Interaction of signaling pathways has an impact on the biological behavior of PC; for example, activation of the neurotensin/NTSR1 pathway, which can activate mitogen-activated protein kinase, nuclear factor-κB, and other pathways related to PC stem cells, play an important role in PC, and an increase in their number is associated with the Wnt/β-catenin and PI3K pathways. Chemotherapy is the main method for the treatment of PC, but drug resistance limits its use. In addition, abnormal activation of IL-17B/IL-17RB signaling pathway is associated with drug resistance. This article discusses the signaling pathways that play different roles in the occurrence and development of PC, as well as current research on signaling pathways in PC treatment.

Deoxyelephantopin Suppresses Pancreatic Cancer Progression In Vitro and In Vivo by Targeting linc00511/miR-370-5p/p21 Promoter Axis.

Objectives Deoxyelephantopin (DET) is a kind of natural active ingredient extracted from the Chinese herbal medicine Elephantopus scaber L. Many studies have revealed the potential antitumor effect on multiple malignancies. However, the detailed mechanism of its antitumor effect in pancreatic cancer remains unclear. Recently, studies have confirmed that noncoding RNA (ncRNA) plays an important regulatory role in malignancies. This research was performed to explore the relationship between ncRNA and DET-induced tumor inhibition in pancreatic cancer. Methods Microarray profiling was applied to identify the candidate ncRNAs associated with DET-induced tumor inhibition. Quantitative real-time PCR was used to evaluate the expression of linc00511 in pancreatic cancer cells and tissues. The influence of DET on the cell proliferation, migration, and invasion was assessed by CCK-8, colony formation, wound healing, and Transwell assays. The relationship between lncRNAs, miRNAs, and p21 promoter region was analyzed by bioinformatics and verified by luciferase reporter gene and western blotting. The effect of linc00511 on nuclear translocation of miR-370-5p was explored by cytoplasmic and nuclear RNA purification. Moreover, the effect of DET on tumor growth and metastasis, and the prophylactic effect were investigated by establishing subcutaneous and lung metastatic tumor models. Results Microarray assay indicated linc00511 was a potential target gene. The antitumor effect of DET in pancreatic cancer depended on downregulating linc00511 expression, and linc00511 might be an oncogene in pancreatic cancer. Silencing linc00511 enhanced the antitumor function of DET; conversely, linc00511 overexpression antagonized the DET cytotoxic effect. Additionally, miR-370-5p could bind to p21 promoter to exert the RNA activation and then promote p21 expression. P21 was a downstream gene of linc00511 and associated with pancreatic cancer progression. Linc00511 regulated p21 expression by blocking miR-370-5p nuclear translocation. Conclusions To sum up, the present finding confirmed that DET suppressed the malignant biological behavior of pancreatic cancer via linc00511/miR-370-5p/p21 promoter axis.

Genome‑wide DNA hypomethylation drives a more invasive pancreatic cancer phenotype and has predictive occult distant metastasis and prognosis potential.

Genome-wide DNA hypomethylation is the most common molecular feature in human cancers associated with chromosomal instability (CIN), which is involved in the mechanisms that regulate pancreatic cancer (PC) metastasis. It was investigated whether genome-wide DNA hypomethylation affects the phenotype in PC via CIN in vitro, and its significance on the biological behavior of PC was verified. The relative demethylation level (RDL) of long interspersed nucleotide element-1 (LINE-1) in human PC cell lines was used to characterize DNA hypomethylation using methylation-specific quantitative (q)PCR. CIN was estimated by changes in chromosomal copy number using comparative genomic hybridization analysis. Abnormal segregation of chromosomes was assessed by immunocytochemistry, and the DNA damage response was evaluated using the number of anti-γH2AX positive cells. Invasion ability was assessed using a Matrigel invasion assay. Clinical specimens from 49 patients with PC who underwent curative surgery were evaluated for a correlation of DNA hypomethylation with clinical outcome. Successful induction of genome-wide DNA hypomethylation in PC cells led to copy number changes in specific chromosomal regions. The number of cells with abnormal segregation of chromosomes significantly increased with the number of anti-γH2AX positive cells. The invasive potential of these cells also significantly increased. The occurrence of occult distant metastasis in the clinical specimens and receiver operating characteristic analysis clearly identified those who were and were not likely to have occult distant metastasis, with high LINE-1 RDL significantly correlated with the presence of occult distant metastasis (P=0.035) and poor prognosis (P=0.048). The significance of genome-wide DNA hypomethylation on the biological behavior of PC, which promotes a more invasive phenotype via CIN in vitro and predicts the susceptibility to occult distant metastasis and poor prognosis in patients with PC was revealed.

ATP11A promotes EMT by regulating Numb PRRL in pancreatic cancer cells.

PurposeThe Numb protein plays a vital role in tumor development. The main aim of this study was to identify ATP11A, which is associated with the biological behavior of pancreatic cancer, and elucidate its relationship with Numb and the underlying mechanism behind this relationship.MethodsFirst, data retrieved from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEX) databases was used to investigate the expression of ATP11A mRNA and its relationship with Numb mRNA in pancreatic cancer. Western blot assays on 31 pairs of pancreatic cancer tissues and paracancerous tissues, and immunohistochemical assays on 81 pancreatic cancer specimens were performed in order to verify the expression of ATP11A in pancreatic cancer at the protein level. Next, ATP11A was overexpressed or knocked down to observe its effects on the invasion and migration ability of pancreatic cancer cells and the changes of downstream proteins. Rescue assays were conducted to determine the mechanism through which ATP11A affects Numb, ZEB1, Snail2 and other proteins. Furthermore, immunoprecipitation assays were performed to explore the interaction between ATP11A and Numb. Finally, pancreatic cancer cells were stimulated with TGFB1 and ATP11A expression was examined to explore whether the effect of ATP11A on EMT was TGFB dependent.ResultsAt the mRNA level, the expression of ATP11A in pancreatic cancer tissues was significantly higher than in normal pancreatic tissues (P < 0.001). ATP11A expression was also highly correlated with Numb expression (R = 0.676). At the protein level, ATP11A expression in pancreatic cancer tissues was significantly higher than that in paracancerous tissues (P = 0.0009), and high ATP11A expression was also correlated with a worse prognosis. Moreover, our results showed that ATP11A can promote the invasion and migration of pancreatic cancer cells. Additionally, ATP11A could positively regulate the expression of Numb PRRL, Snail2 and ZEB1 proteins. The rescue experiment results showed that the enhancement effect of ATP11A on ZEB1/Snail2 was suppressed by the specific knockdown of Numb PRRL. In addition, the immunoprecipitation results showed that ATP11A could specifically bind to Numb PRRL. The expression of ATP11A was also upregulated after TGFB stimulation, suggesting that the effect of ATP11A on EMT is TGFB dependent.ConclusionATP11A is significantly upregulated in pancreatic cancer tissues, where it promotes the invasion and migration ability of pancreatic cancer cells. It is also associated with adverse prognosis in pancreatic cancer. Furthermore, ATP11A affects the epithelial-to-mesenchymal transition (EMT) of pancreatic cancer by regulating the TGFB dependent Numb PRRL-ZEB1/Snail2 pathway.

HTR1D functions as a key target of HOXA10-AS/miR-340-3p axis to promote the malignant outcome of pancreatic cancer via PI3K-AKT signaling pathway

Competing endogenous RNAs (ceRNAs) are a newly discovered class of molecular regulators involved in many diseases, especially tumors. Therefore, exploration of the potential ceRNA regulatory network regarding the occurrence and development of pancreatic cancer will provide a new theoretical basis for its diagnosis and treatment. Based on the above background, we applied a bioinformatics approach to mine the public database The Cancer Genome Atlas (TCGA) and performed a series of subsequent molecular biology assays to confirm the hypothesis that HOXA10-AS/ miR-340-3p/HTR1D axis could modulate the malignant progression of pancreatic cancer. Here, our present study demonstrated that the expression level of HTR1D, positively correlated with the level of lncRNA HOXA10-AS and negatively associated with the level of miR-340-3p, was significantly increased in pancreatic cancer cell lines (PCs) compared with that in normal HPDE6-C7 cells. Knocking down HTR1D obviously inhibited the proliferation and migration of PCs and promoted apoptosis by upregulating p-AKT. Elevated miR-340-3p blocked the progression of pancreatic cancer by downregulating HTR1D. Lessened level of lncRNA HOXA10-AS reduced the sponging of miR-340-3p, resulting in an increase of miR-340-3p and a subsequent decrease of HTR1D to ultimately suppress the malignant biological behaviors of cancer. These data illustrated that the HOXA10-AS/miR-340-3p/HTR1D ceRNA axis acted a crucial part in the malignant biological behavior of pancreatic cancer in an AKT-dependent manner.

Turning towards nonimmunoreactive tumors: Evaluation of cancer-associated fibroblasts enables prediction of the immune microenvironment and treatment sensitivity in pancreatic cancer

Increasing evidence has confirmed that cancer-associated fibroblasts (CAFs) recruit and induce regulatory T cells (Tregs) and macrophages but inhibit cytotoxic T lymphocyte infiltration to a certain extent, indicating that CAFs have a significant influence on the immunosuppressive microenvironment. However, the effect of CAFs on the immune microenvironment and immunotherapy response in pancreatic cancer remains unclear. Our research identified remarkable variation in CAF-associated molecules in multiple cancer types at the genetic and transcriptome levels. Two phenotypes were identified for 476 pancreatic cancer samples, and the different phenotypes exhibited significant variation in immune and inflammatory characteristics. Phenotype 1 exhibited higher levels of immune infiltration and lower expression of tumor-associated gene signatures than phenotype 2. We used a multipart approach to assess the prognostic value of CAF-associated molecules and constructed a CAF score model that could accurately predict patient prognosis. The CAF score accurately predicted infiltrating immune cell abundance, chemosensitivity, and the response to immunotherapy. Additionally, we found that the CAF-associated molecule FGFR4 may promote the proliferation and migration and inhibit the apoptosis of pancreatic cancer cells and is correlated with immune infiltration, suggesting its potential role as an oncogene. CAFs may promote the malignant biological behavior of pancreatic cancer through FGFR4. In summary, our research highlights potential relationships of the dysregulation of CAF-associated molecules with genome alterations and carcinogenesis in multiple malignancies. Our CAF-associated phenotypes and scoring system may enhance the understanding of pancreatic cancer chemotherapy sensitivity and immunotherapy response, providing new insights for personalized chemotherapy and immunotherapy.

Inhibition of Dishevelled-2 suppresses the biological behavior of pancreatic cancer by downregulating Wnt/β-catenin signaling.

Dishevelled-2 (DVL2) has been proven to be involved in the tumorigenesis of several human cancers, such as colorectal cancer, lung cancer, prostate cancer, etc. However, its role in pancreatic ductal adenocarcinoma (PDAC) remains unclear. The present study investigated the effects of aberrantly expressed DVL2 on PDAC. A total of 97 pancreatic cancer (PC) samples and 85 adjacent normal samples were obtained from patients who were histopathologically diagnosed with primary PDAC. The present study demonstrated that DVL2 expression was upregulated in PDAC tissues and was positively associated with advanced clinical stage and lymph node metastasis in patients with PDAC. In addition, patients with high expression of DVL2 had a shorter overall survival rate compared with those with low expression. To elucidate the role of DVL2 in PDAC, lentivirus-mediated short hairpin RNA was used to silence DVL2 and its physiological function was analyzed in CFPAC-1 and PANC-1 cells. The results indicated that DVL2 downregulation significantly impaired its oncogenic functions including cell proliferation, migration, invasion and epithelial-mesenchymal transition. Furthermore, DVL2 knockdown inhibits the proliferation and invasion of PC cells in vivo. In addition, co-immunoprecipitation assays revealed that DVL2 interacted with β-catenin; knockdown of DVL2 reduced the expression level of β-catenin and inhibited β-catenin translocation into the nucleus. In conclusion the findings of the present study suggested that DVL2 may be a potential therapeutic target in the treatment of PDAC.

Hsa-MiR-590-3p Promotes the Malignancy Progression of Pancreatic Ductal Carcinoma by Inhibiting the Expression of p27 and PPP2R2A via G1/S Cell Cycle Pathway.

ObjectiveTo investigate the effect of miR-590-3p on the malignant biological behavior of pancreatic cancer, and to explore the target genes and pathways directly affected by miR-590-3p, to provide new therapeutic ideas and targets for the study of the diagnosis and treatment of pancreatic cancer.MethodsWe used qRT-PCR to measure miR-590-3p expression quantities. We used cell cycle, CCK-8, clonal formation to verify the change of proliferation capacity of PC cells. We used transwell assay to detect the migration and invasion of PC cells. We used the bioinformatics tool TargetScan (http://www.targetscan.org) to identify the possible target genes of miR-590-3p. Immunohistochemistry revealed the clinicopathological significance of PPP2R2A, p27 and miR-590-3p in the expression of pancreatic cancer. Western blot was used to detect the expression changes of PPP2R2A, p27 and G1/S cell cycle pathway-related proteins CDK2, cyclinE2 and p21 after transfection of mimics and inhibitors of miR-590-3p.ResultsAccording to our study, hsa-miR-590-3p expression was significantly higher in PC tissues than that in paired normal pancreas, which was associated with PC tumor size (P=0.042) and preoperative CA19-9 level (P=0.046) of PC patients. Its overexpression promoted PC cell proliferation, invasion and migration following with the p27 and PPP2R2A protein downregulation in Capan-2, PANC-1 and BxPC-3 cells, and vice versa. Bioinformatics analysis and dual-luciferase reporter assay further confirmed that p27 and PPP2R2A were direct target genes of miR-590-3p. The negative relationship of miR-590-3p with p27 and PPP2R2A was also observed in PC tissues.ConclusionMiR-590-3p promotes the proliferation, migration and invasion of pancreatic cancer cells. MiR-590-3p directly downregulated p27 and PPP2R2A and via the G1/S cell cycle pathway to promote the development of pancreatic cancer.

Dilemma and Challenge of Immunotherapy for Pancreatic Cancer.

Pancreatic cancer is a tumor with a high degree of malignancy, morbidity, and mortality. Immunotherapy is another important treatment for pancreatic cancer in addition to surgery and chemotherapy, but its application in pancreatic cancer is very limited, which is related to the unique biological behavior of pancreatic cancer and the tumor microenvironment. The immunosuppressive microenvironment of pancreatic cancer is highly heterogeneous and presents challenges for immunotherapy. The transformation of tumor immunosuppressive microenvironment contributes to the response to tumor immunotherapy, such that the tumor undergoes functional reprogramming to change from immunologically "cold" to immunologically "hot." In this review, we summarized the research and progress in immunotherapy for pancreatic cancer, including immune checkpoint inhibitors, vaccines, adoptive T cell therapy, oncolytic viruses, and immunomodulators, and suggest that individualized, combination, and precise therapy should be the main direction of future immunotherapy in pancreatic cancer.

The regulatory roles of long noncoding RNAs in the biological behavior of pancreatic cancer.

Long noncoding RNAs (lncRNAs) are a new class of regulators. LncRNAs are defined as endogenous transcribed RNA molecules with transcript length of >200 nt. Accumulating evidence has shown that lncRNAs are involved in many physiological processes such as cell cycle regulation, cell apoptosis and survival, cancer migration and metabolism. However, the biological and molecular mechanisms of lncRNAs in pancreatic cancer are still unclear. Recent studies have reported that many lncRNAs are dysregulated in pancreatic cancer and closely associated with tumorigenesis, diagnosis and prognosis. In this review, we described the regulation and functional role of lncRNAs and the potential underlying mechanism involved in pancreatic cancer, outlined the roles of lncRNA in pancreatic cancer, and discussed the potential possibility of lncRNAs as therapeutic targets in clinical practice. Moreover, the potential of lncRNAs used as sensitive biomarkers for diagnosis, prognosis and prediction of response to therapy in pancreatic cancer will also be discussed.

WITHDRAWN: NNK promotes chronic pancreatitis to pancreatic intraepithelial neoplasia and accelerates pancreatic cancer migration

// Xin Chen 1,* , Liang Sheng 1,* , Jiguang Ma 2 , Zhengdong Jiang 1 ,Qinhong Xu 1 , Jianjun Lei 1 , Wanxing Duan 1 , Ligang Nan 1 , Xuqi Li 3 , Zheng Wang 1 , Zheng Wu 1 , Jun Xu 1 , Fengfei Wang 4,5,6,7 , Jason H. Huang 4,6,7 , Erxi Wu 4,6,7,8 , Qingyong Ma 1 and Dong Zhang 1 1 The Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi&rsquo;an Jiaotong University, Xi&rsquo;an, China 2 The Department of Anesthesiology, First Affiliated Hospital of Xi&rsquo;an Jiaotong University, Xi&rsquo;an, China 3 The Department of General Surgery, First Affiliated Hospital of Xi&rsquo;an Jiaotong University, Xi&rsquo;an, China 4 Department of Neurosurgery, Baylor Scott &amp; White Health, Temple, TX, USA 5 Department of Neurology, Baylor Scott &amp; White Health, Temple, TX, USA 6 Neuroscience Institute, Baylor Scott &amp; White Health, Temple, TX, USA 7 Department of Surgery, Texas A &amp; M University College of Medicine, Temple, TX, USA 8 Department of Pharmaceutical Sciences, Texas A &amp; M University College of Pharmacy, College Station, TX, USA * These authors have contributed equally to this work Correspondence to: Erxi Wu, email: erxi.wu@bswhealth.org Qingyong Ma, email: qyma56@mail.xjtu.edu.cn Dong Zhang, email: pavilion1021@hotmail.com Keywords : 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone; sonic hedgehog pathway; chronic pancreatitis; pancreatic cancer Received: October 21, 2017&nbsp;&nbsp;&nbsp;&nbsp; Accepted: December 11, 2017&nbsp;&nbsp;&nbsp;&nbsp; Epub: December 25, 2017 Abstract Smoking has been identified as a categorical environmental risk factor for pancreatic cancer, while the underlying mechanism remains unclear. In the present study, we collect 62 patient samples to explore the effect of smoking on chronic pancreatitis and pancreatic cancer. The biological effect of cigarette carcinogen 4-(methylnitro-samino)-1-(3-pyridyl)-1-butanone (NNK) on pancreatic cancer cells and chronic pancreatitis is determined in vitro and in vivo . We show that smoking promotes Kras mutation and P16 methylation. Through activating Sonic Hedgehog signaling, NNK greatly facilitates the growth and migration of pancreatic cancer cells. More importantly, NNK promotes acinar-to-ductal metastasis (ADM) and pancreatic intraepithelial neoplasia (PanINs) formation in chronic pancreatitis rats, accompanied by desmoplastic reaction and Gli 1 overexpression. Taken together, we reveal that NNK not only promotes the initiation but also accelerates the biological behavior of pancreatic cancer.

Immunoglobulin G4 (IgG4)-positive plasma cell infiltration is associated with the clinicopathologic traits and prognosis of pancreatic cancer after curative resection.

Interactions between pancreatic cancer cells and inflammatory cells play crucial roles in the biological behavior of pancreatic cancer. Abundant infiltration of immunoglobulin G4 (IgG4)-positive plasma cells in the pancreas is the most significant feature of autoimmune pancreatitis; however, the clinical significance of IgG4-positive plasma cell infiltration in pancreatic cancer has not previously been reported. Herein, we analyzed intratumoral and peritumoral infiltrations of IgG4-positive plasma cells in 95 pancreatic cancer cases after curative resection. The correlations between IgG4-positive plasma cell infiltration and the clinicopathologic traits and overall survival of pancreatic cancer were investigated. IgG4-positive plasma cells were found in 86% of tumor tissue samples compared with 69% of peritumoral tissue samples (P=0.0063). The high-level infiltration of intratumoral IgG4-positive plasma cells was positively correlated with poor histological grade (P=0.017). The high-level infiltration of intratumoral IgG4-positive plasma cells was significantly correlated with worse prognosis (P=0.01) in multivariate analysis. We further found that intratumoral M2-polarized tumor-associated macrophages (TAMs) were positively, linearly correlated with IgG4-positive plasma cells. In conclusion, IgG4-positive plasma cell infiltration is correlated with the clinicopathologic traits and overall survival of pancreatic cancer. High-level intratumoral infiltration of IgG4-positive plasma cells is an independent predictor for poor overall survival in pancreatic cancer patients after curative resection. Intratumoral M2-polarized TAMs probably induce IgG4-positive plasma cells.

CXCL12-CXCR4 Promotes Proliferation and Invasion of Pancreatic Cancer Cells

CXCL12 exerts a wide variety of chemotactic effects on cells. Evidence indicates that CXCL12, in conjunction with its receptor, CXCR4, promotes invasion and metastasis of tumor cells. Our objective was to explore whether the CXCL12-CXCR4 biological axis might influence biological behavior of pancreatic cancer cells. Miapaca-2 human pancreatic cancer cells were cultured under three different conditions: normal medium (control), medium + recombinant CXCL12 (CXCL12 group), or medium + CXCR4-inhibitor AMD3100 (AMD3100 group). RT-PCR was applied to detect mRNA expression levels of CXCL12, CXCR4, matrix metalloproteinase 2 (MMP-2), MMP-9, and human urokinase plasminogen activator (uPA). Additionally, cell proliferation and invasion were performed using CCK-8 colorimetry and transwell invasion assays, respectively. CXCL12 was not expressed in Miapaca-2 cells, but CXCR4 was detected, indicating that these cells are capable of receiving signals from CXCL12. Expression of extracellular matrix-degrading enzymes MMP-2, MMP- 9, and uPA was upregulated in cells exposed to exogenous CXCL12 (P<0.05). Additionally, both proliferation and invasion of pancreatic cancer cells were enhanced in the presence of exogenous CXCL12, but AMD3100 intervention effectively inhibited these processes (P<0.05). The CXCL12-CXCR4 biological axis plays an important role in promoting proliferation and invasion of pancreatic cancer cells.

Down regulation of CAII is associated with tumor differentiation and poor prognosis in patients with pancreatic cancer

Altered expression of carbonic anhydrase (CA)I and II associated with human carcinogenesis. But there was no definite study investigating their expression for clinical significance in pancreatic cancer and effect of the CA inhibitor acetazolamide (AZ) on regulation biological behavior of pancreatic cancer cells. Immunohistochemistry, immunofluorescence, immunoblot, and qRT-PCR were used to detect CAI, II, and p53 expression. Tumor cell viability, apoptosis, and invasion assays were used to investigate the effect of AZ on pancreatic cancer cells. Expression of CAI and p53 was increased in pancreatic cancer than that in paired non-cancerous tissues (P = 0.021; P = 0.007), whereas CAII was down-regulated in pancreatic cancer (P = 0.001). CAI overexpression was associated with tumor differentiation and negatively with vascular invasion (P = 0.015 and P = 0.018, respectively), while overexpression of CAII was associated with tumor differentiation (P = 0.017) and a better prognosis of pancreatic cancer patients (P = 0.017), and was an independent prognostic indicator (P = 0.011). p53 overexpression was related with lymph node metastasis (P = 0.032) and TNM stage (P = 0.016). Treatment with AZ inhibited tumor cell validity, invasion, and induced apoptosis in some of six pancreatic cancer cells. This study suggests the clinical significance of CAI, CAII and p53 expression in pancreatic cancer and provides evidence for AZ as a potential target for controlling pancreatic cancer.

Clinical implications of mismatched repair gene promoter methylation in pancreatic cancer

To investigate the relationship between the hypermethylation statuses of the mismatch repair genes (hMLH1 and hMSH2) promoters and explore the correlation between it and the development of pancreatic cancer and the biological behavior of pancreatic cancer. We selected 90 patients who were diagnosed with pancreatic cancer and underwent radical operations in the First Affiliated Hospital of the Dalian Medical University between January 2002 and June 2008. The methylation status of the hMLH1 and hMSH2 promoters was detected by methylation-specific polymerase chain reaction (MSP). Meanwhile, the expression of hMLH1 and hMSH2 protein was detected by Western blot and immunohistochemistry, and its correlation with biological behavior of pancreatic cancer was explored. Of the 90 cases, hMLH1 promoter methylation was detected in 54 (60.0%) patients, while none of the paracancerous tissues indicated methylation. In the study, the hMLH1-methylated tumors lost hMLH1 protein expression, but the non-hMLH1-methylated tumors were not seen to have a loss of hMLH1 protein expression (P < 0.001). On the other hand, there were four cases of hMSH2 promoter methylation. However, no significant difference was found between hMSH2 promoter methylation and non-hMSH2 promoter methylation cases (P > 0.05). After universal analysis, hMLH1 expression was significantly related to tumor differentiation, lymph node metastasis, and tumor location (P < 0.05) while not related to the age, sex, and tumor size (P > 0.05). Our study suggests that the mismatch repair genes play an important role in pancreatic cancer carcinogenesis and progression through epigenetic modification, and it may be regarded as a potential target for the management of pancreatic cancer.

Gli1 maintains cell survival by up-regulating IGFBP6 and Bcl-2 through promoter regions in parallel manner in pancreatic cancer cells

Background:Aberrant activation of Hedgehog (Hh) signaling pathway has been reported to be related to malignant biological behavior of pancreatic cancer but its mechanism is unclear yet. Since IGF pathway and Bcl-2 family are involved in proliferation and apoptosis of pancreatic cancer cells, we hypothesize that they are possibly associated with Hh pathway.Materials and Methods:We studied the relationship of Shh-Gli1 signaling pathway with proliferation and apoptosis of pancreatic cancer cells and the regulation of transcription factor Gli1 to insulin-like growth factor binding protein 6 (IGFBP6) and Bcl-2 genes at the level of transcription.Results:Sonic hedgehog (Shh), Smoothened (Smo), patched and Gli1 were expressed in pancreatic cancer cells. Cyclopamine inhibited cell proliferation at low concentration and induced apoptosis at high concentration. Effect of RNA interference (RNAi) for Gli1 to cell survival is mainly due to proliferation inhibition though involved in apoptosis. The transcription factor Gli1 bound to promoter regions of Bcl-2 and IGFBP6 genes and the levels of IGFBP6, proliferating cell nuclear antigen (PCNA) and Bcl-2 messenger RNA (mRNA) were decreased as well as Gli1 mRNA significantly by cyclopamine or RNAi in cultured pancreatic cancer cells (p < 0.01). Finally PCNA, IGFBP6 and Bcl-2 mRNA were upregulated as well as Shh or Gli1 in pancreatic cancer tissues (p < 0.01).Conclusions:Our study reveals that Gli1 maintained cell survival by binding the promoter regions and facilitating transcription of IGFBP6 and Bcl-2 genes in a parallel manner in pancreatic cancer cells and suggests it may be one of the mechanisms of Shh-Gli1 signaling pathway in pancreatic cancer.