Therapeutic Target For Pancreatic Ductal Adenocarcinoma Research Articles

A self-amplifying USP14-TAZ loop drives the progression and liver metastasis of pancreatic ductal adenocarcinoma

With a 5-year survival rate of approximately 10%, pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal solid malignancies in humans. A poor understanding of the underlying biology has resulted in a lack of effective targeted therapeutic strategies. Tissue microarray and bioinformatics analyses have revealed that the downstream transcriptional coactivator of the Hippo pathway, transcriptional coactivator with PDZ-binding motif (TAZ), might be a therapeutic target in PDAC. Since pharmacological inhibition of TAZ is challenging, we performed unbiased deubiquitinase (DUB) library screening to explore the pivotal regulators of TAZ ubiquitination as potential targets in PDAC models. We found that USP14 contributed to Yes-associated protein (YAP)/TAZ transcriptional activity and stabilized TAZ but not YAP. Mechanistically, USP14 catalyzed the K48-linked deubiquitination of TAZ to promote TAZ stabilization. Moreover, TAZ facilitated the transcription of USP14 by binding to the TEA domain transcription factor (TEAD) 1/4 response element in the promoter of USP14. USP14 was found to modulate the expression of TAZ downstream target genes through a feedback mechanism and ultimately promoted cancer progression and liver metastasis in PDAC models in vitro and in vivo. In addition, depletion of USP14 led to proteasome-dependent degradation of TAZ and ultimately arrested PDAC tumour growth and liver metastasis. A strong positive correlation between USP14 and TAZ expression was also detected in PDAC patients. The small molecule inhibitor of USP14 catalytic activity, IU1, inhibited the development of PDAC in subcutaneous xenograft and liver metastasis models. Overall, our data strongly suggested that the self-amplifying USP14-TAZ loop was a previously unrecognized mechanism causing upregulated TAZ expression, and identified USP14 as a viable therapeutic target in PDAC.

Antibody-mediated blockade for galectin-3 binding protein in tumor secretome abrogates PDAC metastasis

The major challenges in pancreatic ductal adenocarcinoma (PDAC) management are local or distant metastasis and limited targeted therapeutics to prevent it. To identify a druggable target in tumor secretome and to explore its therapeutic intervention, we performed a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteomic analysis of tumors obtained from a patient-derived xenograft model of PDAC. Galectin-3 binding protein (Gal-3BP) is identified as a highly secreted protein, and its overexpression is further validated in multiple PDAC tumors and primary cells. Knockdown and exogenous treatment of Gal-3BP showed that it is required for PDAC cell proliferation, migration, and invasion. Mechanistically, we revealed that Gal-3BP enhances galectin-3-mediated epidermal growth factor receptor signaling, leading to increased cMyc and epithelial-mesenchymal transition. To explore the clinical impact of these findings, two antibody clones were developed, and they profoundly abrogated the metastasis of PDAC cells invivo. Altogether, our data demonstrate that Gal-3BP is an important therapeutic target in PDAC, and we propose its blockade by antibody as a therapeutic option for suppressing PDAC metastasis.

Targeting autophagy as a therapeutic strategy against pancreatic cancer

Macroautophagy (hereafter autophagy) is a catabolic process through which cytosolic components are captured in the autophagosome and degraded in the lysosome. Autophagy plays two major roles: nutrient recycling under starvation or stress conditions and maintenance of cellular homeostasis by removing the damaged organelles or protein aggregates. In established cancer cells, autophagy-mediated nutrient recycling promotes tumor progression, whereas in normal/premalignant cells, autophagy suppresses tumor initiation by eliminating the oncogenic/harmful molecules. Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease that is refractory to most currently available treatment modalities, including immune checkpoint blockade and molecular-targeted therapy. One prominent feature of PDAC is its constitutively active and elevated autophagy-lysosome function, which enables PDAC to thrive in its nutrient-scarce tumor microenvironment. In addition to metabolic support, autophagy promotes PDAC progression in a metabolism-independent manner by conferring resistance to therapeutic treatment or facilitating immune evasion. Besides to cell-autonomous autophagy in cancer cells, host autophagy (autophagy in non-cancer cells) supports PDAC progression, further highlighting autophagy as a promising therapeutic target in PDAC. Based on a growing list of compelling preclinical evidence, there are numerous ongoing clinical trials targeting the autophagy-lysosome pathway in PDAC. Given the multifaceted and context-dependent roles of autophagy in both cancer cells and normal host cells, a deeper understanding of the mechanisms underlying the tumor-promoting roles of autophagy as well as of the consequences of autophagy inhibition is necessary for the development of autophagy inhibition-based therapies against PDAC.

Abstract 5330: Nuclear protein export inhibitor selinexor chemotherapy combination for pancreatic cancer therapy

Abstract Background: The majority of pancreatic ductal adenocarcinoma (PDAC) patients experience disease progression after Gemcitabine-nab-Paclitaxel (GemPac) treatment indicating the need for more effective combination therapies for this highly recalcitrant disease. Earlier we showed that nuclear exporter protein exportin 1 (XPO1) is a valid therapeutic target in PDAC and selective inhibitor of nuclear export (SINE) selinexor (Sel), synergistically enhances the efficacy of GemPac in pancreatic cancer cells, spheroids, patient derived tumors and showed evaluable response in PDAC patients in a Phase I study. Here we investigated the mechanisms of this synergy utilizing PDAC cellular models in vitro and LSL-Kras G12D/+; Trp53 fl/+; Pdx1-Cre (KPC) mouse model. Methods: We used single-nuclei RNA sequencing in KPC tumors, and poly A RNA sequencing in PDAC cells post sel-Gem-Pac treatment. Prioritized sn-seq and RNA-seq identified molecules were validated in in vitro or in the PDAC patient samples through siRNA mediated silencing, quantitative gene expression, cytotoxicity and related assays. Results: In KPC model, selinexor-GemPac caused statistically significant enhancement in survival compared to controls (p less than 0.05). Molecular analysis of residual KPC tumors showed re-organization of tumor stromal architecture, suppression of proliferation and nuclear retention of tumor suppressors. Histopathological analysis for Ki67 suggests comparatively lower rate of proliferation and enhanced nuclear accumulation of FOXO3a in the treated mice. Loosening of stroma and lowering of collagen fiber is also evident in treated mice from Picrosirius and Masson’s trichrome staining. Additionally, the KPC derived primary tumor cells showed reduced colony formation upon combination treatment. Sn-seq showed reduction in tumor cell heterogeneity (less cell clusters based on gene expression), CDK8, CD44 and Camk1d stem cell and EMT related genes alongside significant alterations in mitochondrial signaling after combination treatment. In cellular models, GO and GSEA analyses of RNA-seq data predicted DNA templated regulation of transcription and DNA replication associated genes in Sel or Sel-GemPac mediated growth inhibition. The top downregulated genes including drug resistant related gene PFN1 and HSP90 identified in Sel or Sel-GemPac treated PDAC cells from RNA-seq data were validated using RNAi and confirmed their role in synergy. Conclusions: Taken together Selinexor in combination with Gemcitabine-nab-Paclitaxel enhanced the survival of KPC mice through inhibition of well-connected tumor promoting molecules resulting in broad penetration in PDAC supporting signaling. A phase II study involving selinexor-gemcitabine combination in patients with metastatic PDAC is ongoing. Citation Format: Md. Hafiz Uddin, Sahar Bannoura, Yiwei Li, Husain Y. Khan, Amro Aboukameel, Mohammed N. Al-Hallak, Rafic Beydoun, Steve Kim, Yosef Landesman, Ramzi M. Mohammad, Anthony Shields, Asfar S. Azmi. Nuclear protein export inhibitor selinexor chemotherapy combination for pancreatic cancer therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5330.

Abstract 5491: Targeting importin-YAP axis in pancreatic ductal adenocarcinoma

Abstract Background: To date, pancreatic ductal adenocarcinoma (PDAC) remains to have a dismal prognosis, with a 5-year survival rate of only 10%, which brings out an imperative to develop new therapeutic strategies to improve patient outcome. Recently, aberrant nucleocytoplasmic transport machinery in cancer cells has emerged as a rational therapeutic target. We aim to validate the nuclear importin complex involved in the import of macromolecules across the nuclear membrane as a potential therapeutic target in PDAC. Methods: Tet-inducible shRNA and FDA-approved agent (Ivermectin) were used for the inhibition of importins. Cell death (apoptosis and pyroptosis) was detected by western blot. In vivo tumor growth of human and mouse PDAC cells was evaluated in immunocompetent and immunodeficient animal models. MTT assay was employed to evaluate the patient-derived organoid viability following drug treatment. Results: We found that PDAC cells/patients harbored unusually higher levels of importins. Inducible knockdown of importin-α2/α5 (KPNA2/KPNA1) or importin-β1 (KPNB1) strongly suppressed PDAC tumor growth and induced apoptosis and pyroptosis. Interestingly, the importin inhibitor Ivermectin (an FDA-approved antiparasitic agent) worked effectively in PDAC cells, patient-derived organoids and animal models. Mechanistically, we show that importins associate with YAP (the transcriptional coactivator of the Hippo pathway) and control its expression at mRNA levels. In line with these observations, the expression levels of importin-αs, importin-β1, and YAP are positively correlated in PDAC patients. Conclusion: Our study identifies the importin complex as a prognostic marker and therapeutic target for pancreatic cancer and is expected to provide preclinical evidence for the evaluation of Ivermectin in PDAC patients. Citation Format: Renya Zeng, Jixin Dong. Targeting importin-YAP axis in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5491.

Overexpression of laminin-5 gamma-2 promotes tumorigenesis of pancreatic ductal adenocarcinoma through EGFR/ERK1/2/AKT/mTOR cascade.

Pancreatic ductal adenocarcinoma (PDAC) is correlated with poor outcomes because of limited therapeutic options. Laminin-5 gamma-2 (LAMC2) plays a critical role in key biological processes. However, the detailed molecular mechanism and potential roles of LAMC2 in PDAC stay unexplored. The present study examines the essential role and molecular mechanisms of LAMC2 in the tumorigenesis of PDAC. Here, we identified that LAMC2 is significantly upregulated in microarray cohorts and TCGA RNA sequencing data of PDAC patients compared to non-cancerous/normal tissues. Patients with higher transcript levels of LAMC2 were correlated with clinical stages; dismal overall, as well as, disease-free survival. Additionally, we confirmed significant upregulation of LAMC2 in a panel of PDAC cell lines and PDAC tumor specimens in contrast to normal pancreatic tissues and cells. Inhibition of LAMC2 significantly decreased cell growth, clonogenic ability, migration and invasion of PDAC cells, and tumor growth in the PDAC xenograft model. Mechanistically, silencing of LAMC2 suppressed expression of ZEB1, SNAIL, N-cadherin (CDH2), vimentin (VIM), and induced E-cadherin (CDH1) expression leading to a reversal of mesenchymal to an epithelial phenotype. Interestingly, co-immunoprecipitation experiments demonstrated LAMC2 interaction with epidermal growth factor receptor (EGFR). Further, stable knockdown of LAMC2 inhibited phosphorylation of EGFR, ERK1/2, AKT, mTOR, and P70S6 kinase signaling cascade in PDAC cells. Altogether, our findings suggest that silencing of LAMC2 inhibited PDAC tumorigenesis and metastasis through repression of epithelial-mesenchymal transition and modulation of EGFR/ERK1/2/AKT/mTOR axis and could be a potential diagnostic, prognostic, and therapeutic target for PDAC.

Identification of significant prognostic risk markers for pancreatic ductal adenocarcinoma: a bioinformatic analysis.

This study aimed to identify novel prognostic biomarkers of pancreatic ductal adenocarcinoma (PDAC) using bioinformatics analyzes. Clinical information, microRNAs (miRNAs), and genes expression profile data from PDAC cases were downloaded from the Cancer Genome Atlas (TCGA) database. The potential prognostic risk miRNAs and genes were screened using the Elastic Net Cox proportional risk regression hazards (EN-COX) model. The receiver operating characteristic (ROC) curve and the Kaplan-Meier (KM) curve were used to identify miRNAs and genes of significant prognostic risk. Furthermore, significant prognostic risk miRNAs were functional enrichment analyses based on their target genes. Furthermore, the survival analyzes of the hub genes were validated through OncoLnc. Complete clinical records and expression data of 797 miRNAs and 19969 genes from 137 PDAC cases were obtained, of which 59 potential prognostic risk factors, including 54 genes and 5 miRNAs, were selected by EN-COX analyzes. A total of 17 significant prognostic risk markers were identified (all P<0.05), including 16 genes and 1 miRNA (miRNA-125a). The miRNA-125a target genes were found in the MiRWalk database and the function enrichment analyzes were performed in the the DAVID website. Furthermore, according to data from the Oncomine and Human Protein Atlas (HPA) databases, the mRNA and protein level of frizzled class receptor 8 (FZD8) were overexpressed in pancreatic cancer tissues compared to the corresponding noncancer normal tissues (P<0.001). However, both glutathione S-transferase mu 4 (GSTM4) and inducible T cell costimulator ligand (ICOSLG) were negatively regulated in tissues of pancreatic cancer tissues (P<0.001). Finally, survival analysis was used to validate these factors by the OncoLnc database, and the results revealed that overexpression of ICOSLG was associated with a better prognosis (P=0.025). This study showed that the expression levels of FZD8, GSTM4 and ICOSLG were significantly different between PDAC and non-tumor tissues, especially ICOSLG, which could be a prognostic indicator and therapeutic target for PDAC.

Interleukin 6/gp130 axis promotes neural invasion in pancreatic cancer.

Nerve invasion (N-inv) is an important prognostic factor in pancreatic ductal adenocarcinoma (PDAC). Elucidation of circulating N-inv stimulators could provide deeper insights and novel perspectives for PDAC therapy. The interleukin (IL)-6/gp130 axis was evaluated in this study as a candidate N-inv stimulator. A human pancreatic cancer (PC) cell, Capan-1, was confirmed to have the stimulant activity of IL-6/gp130 axis through the evaluation of mRNA, cell surface protein and intracellular protein levels and chemotaxis and wound healing assay. The upregulation of IL-6/gp130 axis was evaluated using tumor-derived IL-6 level and intratumoral pSTAT3 expression in N-inv of murine sciatic nerves by intraneural injection of Capan-1 cell (N-inv model) and using resected pancreatic cancer tissue and clinical data from 46 PDAC patients. mRNA and protein expressions of IL-6 and IL-6 receptor were found in whole cell lysate and condition medium from PC cell. Cell surface protein expression of gp130 were clearly detected on PC cell. IL-6 promoted migration and chemotaxis of PC cell. Serum IL-6 and tumoral IL-6 mRNA levels in N-inv model mice were significantly higher than those in subcutaneous tumor mice (p = 0.004 and p = 0.002, respectively). Silencing of IL-6 and gp130 on PC cell and administration of an anti-IL-6 receptor antibody, tocilizumab, suppressed N-inv, compared to each control (p = 0.070, p = 0.118 and p = 0.122, respectively). In PDAC patients, the high-N-inv group showed poor prognosis (p =0.059) and elevated serum levels of IL-6 and C-reactive protein, synthesis of which is promoted by IL-6, compared to those in the low-N-inv group (p = 0.006 and p = 0.075, respectively). Tumoral gp130 expression at N-inv was higher than that in the primary pancreatic tumor (p = 0.026). Biological activity of IL-6/gp130 axis promoted N-inv in murine model and was upregulated in PDAC patients with severe N-inv. This study is the first evidence that the IL-6/gp130 axis offers a potential therapeutic target in PDAC with N-inv.

Identification of potential core genes at single-cell level contributing to pathogenesis of pancreatic ductal adenocarcinoma through bioinformatics analysis.

Pancreatic ductal adenocarcinoma (PDAC) prognosis has not improved over the last decades because of the lack of effective diagnostic and therapeutic methods in the early stage of the disease. Several gene expression profiles were downloaded from the Expression Omnibus (GEO) database. We calculated the differentially expressed mRNAs (DEGs) and miRNAs (DEmiRs). Then, we constructed a miRNA-mRNA regulatory network by using the miRWalk database. For the DEGs regulated by DEmiRs, we introduced GEPIA to confirm these DEGs' expression and effect on overall survival. We used other GEO datasets and mRNA-miRNA target databases to validate these DEGs and their relationship with DEmiRs. All these potential core DEGs regulated by DEmiRs were also analyzed at the single-cell level to confirm their cell type source. CCNB2 and KCNN4, which were regulated by several micro RNAs, showed relatively high expression levels in PDAC patients and significant association with worse overall survival. Furthermore, we identified many DEGs at single-cell level and found that 10 oncogenes were significantly upregulated in type 2 ductal cell type, thereby further demonstrating that type 2 ductal cells might be major sources of malignant cells and are valuable therapeutic targets in PDAC. Our data added some new insights into the molecular mechanism of PDAC and may be helpful for finding potential biomarkers for diagnosis. These discovery at single-cell level may also be useful for developing new therapeutic targets for PDAC patients.

Targeting BPTF Sensitizes Pancreatic Ductal Adenocarcinoma to Chemotherapy by Repressing ABC-Transporters and Impairing Multidrug Resistance (MDR).

Simple SummaryPancreatic ductal adenocarcinoma is a devastating disease and an extremely chemoresistant tumour. In the present manuscript, we described the role of BPTF during tumour pancreatic ductal adenocarcinoma progression and in response to gemcitabine treatment, a gold standard treatment in this tumour type. Through different genetic approaches, we reduced BPTF levels in a panel of pancreatic ductal adenocarcinoma cell lines. We validated its therapeutic effect in cell cultures and in mouse models of pancreatic cancer. A reduction in BPTF levels impaired cell proliferation and sensitized pancreatic tumour cells to gemcitabine. We demonstrated that BPTF-silencing reduced the expression of several ABC-transporters, which are involved in gemcitabine resistance, and enhanced its accumulation in the tumour cell, improving its therapeutic effect.Pancreatic ductal adenocarcinoma (PDA) is characterized by an extremely poor prognosis due to its late diagnosis and strong chemoresistance to the current treatments. Therefore, finding new therapeutic targets is an urgent need nowadays. In this study, we report the role of the chromatin remodeler BPTF (Bromodomain PHD Finger Transcription Factor) as a therapeutic target in PDA. BPTF-silencing dramatically reduced cell proliferation and migration in vitro and in vivo in human and mouse PDA cell lines. Moreover, BPTF-silencing reduces the IC50 of gemcitabine in vitro and enhanced its therapeutic effect in vivo. Mechanistically, BPTF is required for c-MYC recruitment to the promoter of ABC-transporters and its downregulation facilitates gemcitabine accumulation in tumour cells, increases DNA damage, and a generates a strong synergistic effect in vivo. We show that BPTF is a therapeutic target in pancreatic ductal adenocarcinoma due to its strong effect on proliferation and in response to gemcitabine.

The human AP-endonuclease 1 (APE1) is a DNA G-quadruplex structure binding protein and regulates KRAS expression in pancreatic ductal adenocarcinoma cells.

Pancreatic ductal adenocarcinoma (PDAC), one of the most aggressive types of cancer, is characterized by aberrant activity of oncogenic KRAS. A nuclease-hypersensitive GC-rich region in KRAS promoter can fold into a four-stranded DNA secondary structure called G-quadruplex (G4), known to regulate KRAS expression. However, the factors that regulate stable G4 formation in the genome and KRAS expression in PDAC are largely unknown. Here, we show that APE1 (apurinic/apyrimidinic endonuclease 1), a multifunctional DNA repair enzyme, is a G4-binding protein, and loss of APE1 abrogates the formation of stable G4 structures in cells. Recombinant APE1 binds to KRAS promoter G4 structure with high affinity and promotes G4 folding in vitro. Knockdown of APE1 reduces MAZ transcription factor loading onto the KRAS promoter, thus reducing KRAS expression in PDAC cells. Moreover, downregulation of APE1 sensitizes PDAC cells to chemotherapeutic drugs in vitro and in vivo. We also demonstrate that PDAC patients’ tissue samples have elevated levels of both APE1 and G4 DNA. Our findings unravel a critical role of APE1 in regulating stable G4 formation and KRAS expression in PDAC and highlight G4 structures as genomic features with potential application as a novel prognostic marker and therapeutic target in PDAC.

Pseudogene AK4P1 promotes pancreatic ductal adenocarcinoma progression through relieving miR-375-mediated YAP1 degradation.

Pseudogenes have been reported to play oncogenic or tumor-suppressive roles in cancer progression. However, the molecular mechanism of most pseudogenes in pancreatic ductal adenocarcinoma (PDAC) remains unknown. Herein, we characterized a novel pseudogene-miRNA-mRNA network associated with PDAC progression using bioinformatics analysis. After screening by dreamBase and GEPIA, 12 up-regulated and 7 down-regulated differentially expressed pseudogenes (DEPs) were identified. According to survival analysis, only elevated AK4P1 indicated a poor prognosis for PDAC patients. Moreover, we found that AK4 acts as a cognate gene of AK4P1 and also predicts worse survival for PDAC patients. Furthermore, 32 miRNAs were predicted to bind to AK4P1 by starBase, among which miR-375 was identified as the most potential binding miRNA of AK4P1. A total of 477 potential target genes of miR-375 were obtained by miRNet, in which 49 hub genes with node degree ≥ 20 were identified by STRING. Subsequent analysis for hub genes demonstrated that YAP1 may be a functional downstream target of AK4P1. To confirmed the above findings, microarray, and qRT-PCR assay revealed that YAP1 was dramatically upregulated in both PDAC cells and tissues. Functional experiments showed that knockdown of YAP1 significantly suppressed PDAC cells growth, increased apoptosis, and decreased the ability of invasion. In conclusion, amplification of AK4P1 may fuel the onset and development of PDAC by targeting YAP1 through competitively binding to miR-375, and serve as a promising biomarker and therapeutic target for PDAC.

Ziprasidone suppresses pancreatic adenocarcinoma cell proliferation by targeting GOT1 to trigger glutamine metabolism reprogramming.

Pancreatic ductal adenocarcinoma (PDAC) is a fatal malignant tumor whose effective treatment has not been found. The redox state and proliferative activity of PDAC cells are maintained by the conversion of aspartic acid in the cytoplasm into oxaloacetate though aspartate aminotransferase 1 (GOT1). Therefore, GOT1 inhibitors as a potential approach for treating PDAC have attracted more attention of researchers. Ziprasidone effectively inhibited GOT1 in a non-competitive manner. The potential cytotoxicity and anti-proliferation effects of ziprasidone against PDAC cells in vitro and in vivo were evaluated. Ziprasidone can induce glutamine metabolism disorder and redox state imbalance of PDAC cells by targeting GOT1, thereby inhibiting proliferation, preventing migration, and inducing apoptosis. Ziprasidone displayed significant in vivo antitumor efficacy in SW1990 cell-derived xenografts. What's more, knockdown of GOT1 in SW1990 reduced the anti-proliferative effects of ziprasidone. As a novel GOT1 inhibitor, ziprasidone may be a lead compound for the treatment of PDAC. KEY MESSAGES: Small molecule inhibitors targeting GOT1 may provide a therapeutic target in PDAC. Ziprasidone effectively inhibited GOT1 enzyme in a non-competitive manner. Ziprasidone repressed glutamine metabolism and inhibited the growth of tumor in vivo. Knockdown of GOT1 decreased the anti-proliferative effects of ziprasidone.

RASAL2 mediated the enhancement of YAP1/TIAM1 signaling promotes malignant phenotypes of pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a high incidence of metastasis and dismal prognosis. As a member of Gas-Gap gene, RASAL2 is involved in the hydrolysis of RAS-GTP to RAS-GDP and abnormal expression in human cancers. Here we firstly described the function of RASAL2 on PDAC to enrich the knowledge of RAS family.We interestingly observed that RASAL2 expression was upregulated in PDAC at both mRNA and protein levels, and high expression of RASAL2 predicted a poor prognosis in PDAC patients. Additionally, RASAL2 promoted malignant behaviors of PDAC in vitro and in vivo. To determine the mechanistic roles of RASAL2 signaling and its potential as a therapeutic target in PDAC, we clarified that RASAL2 could accumulate the TIAM1 expression in different level through inhibiting YAP1 phosphorylation, increased TIAM1 mRNA expression and suppressed ubiquitination of TIAM1 protein. In conclusion, RASAL2 enhances YAP1/TIAM1 signaling and promotes PDAC development and progression.

Prediction of Tumor-Infiltrating CD20+ B-Cells in Patients with Pancreatic Ductal Adenocarcinoma Using a Multilayer Perceptron Network Classifier Based on Non-contrast MRI

Conventional chemotherapy has limited benefit in pancreatic ductal adenocarcinoma (PDAC), necessitating identification of novel therapeutic targets. Radiomics may enable non-invasive prediction of CD20 expression, a hypothesized therapeutic target in PDAC. To develop a machine learning classifier based on noncontrast magnetic resonance imaging for predicting CD20 expression in PDAC. Retrospective study was conducted on preoperative noncontrast magnetic resonance imaging of 156 patients with pathologically confirmed PDAC from January 2017 to April 2018. For each patient, 1409 radiomics features were selected using minimum absolute contraction and selective operator logistic regression algorithms. CD20 expression was quantified using immunohistochemistry. A multilayer perceptron network classifier was developed using the training and validation set. A log-rank test showed that the CD20-high group (22.37 months, 95% CI: 19.10-25.65) had significantly longer survival than the CD20-low group (14.9 months, 95% CI: 10.96-18.84). The predictive model showed good differentiation in training (area under the curve [AUC], 0.79) and validation (AUC, 0.79) sets. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 73.21%, 75.47%, 0.74, 0.76, and 0.73, respectively, for the training set and 69.23%, 80.95%, 0.74, 0.82, and 0.68, respectively, for the validation set. Multilayer perceptron classifier based on noncontrast magnetic resonance imaging scanning can predict the level of CD20 expression in PDAC patients.

Glypican-1 Is a Novel Target for Stroma and Tumor Cell Dual-Targeting Antibody-Drug Conjugates in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is a stroma-rich cancer. Extracellular matrix proteins produced by cancer-associated fibroblasts (CAFs) found in tumor stroma that impedes effective delivery of chemotherapeutic agents results in poor response in patients with PDAC. Previously, our group reported that glypican-1 (GPC1) was overexpressed in human PDAC and negatively correlated with patient survival. Immunohistochemical analysis of 25 patients with PDAC tumor specimens revealed elevated expression of GPC1 in stromal cells and pancreatic cancer cells in 80% of patients. Interestingly, GPC1 was expressed on CAFs in PDAC. We generated a GPC1 antibody-drug conjugate conjugated with monomethyl auristatin E [GPC1-ADC(MMAE)] and evaluated its preclinical antitumor activity by targeting GPC1-positive CAF and cancer cells in PDAC. GPC1-ADC(MMAE) inhibited the growth of GPC1-positive PDAC cell lines in vitro Furthermore, GPC1-ADC(MMAE) showed a potent antitumor effect in the PDAC patient-derived tumor xenograft (PDX) model against GPC1-positive CAF and heterogeneous GPC1-expressing cancer cells. Notably, GPC1-ADC(MMAE) showed robust preclinical efficacy against GPC1 in a stroma-positive/cancer-negative PDAC PDX model. GPC1-ADC(MMAE) was delivered and internalized to CAFs. Although apoptosis was not observed in CAFs, the released MMAE from CAFs via MDR-1 induced apoptosis of cancer cells neighboring CAFs and efficiently inhibited PDAC tumor growth. GPC1-ADC(MMAE) exhibited potent and unique antitumor activity in GPC1-positive PDAC PDX models, which suggests that GPC1 is a novel therapeutic target in PDAC and other stromal GPC1-positive solid tumors. These findings show that targeting GPC1 on CAF using GPC1-ADC(MMAE) is a useful approach in case of stroma-rich tumors such as PDAC.

NR2F1-AS1 Promotes Pancreatic Ductal Adenocarcinoma Progression Through Competing Endogenous RNA Regulatory Network Constructed by Sponging miRNA-146a-5p/miRNA-877-5p.

The role of NR2F1-AS1 in pancreatic ductal adenocarcinoma (PDAC) remains unknown. Therefore, we aimed to investigate the biological mechanism of NR2F1-AS1 in PDAC. The expression of NR2F1-AS1 was measured by using microarray data and real-time PCR. The effects of NR2F1-AS1 knockdown on proliferation, cell cycle progression, invasion in vitro and tumorigenesis in vivo were investigated. The mechanism of competitive endogenous RNAs was determined from bioinformatics analyses and validated by a dual-luciferase reporter gene assay. Potential target mRNAs from TargetScan 7.2 were selected for subsequent bioinformatics analysis. Key target mRNAs were further identified by screening hub genes and coexpressed protein-coding genes (CEGs) of NR2F1-AS1. NR2F1-AS1 was highly expressed in PDAC, and the overexpression of NR2F1-AS1 was associated with overall survival and disease-free survival. The knockdown of NR2F1-AS1 impaired PDAC cell proliferation, migration, invasion and tumorigenesis. NR2F1-AS1 competitively sponged miR-146a-5p and miR-877-5p, and low expression of the two miRNAs was associated with a poor prognosis. An integrative expression and survival analysis of the hub genes and CEGs demonstrated that the NR2F1-AS1–miR-146a-5p/miR-877-5p–GALNT10/ZNF532/SLC39A1/PGK1/LCO3A1/NRP2/LPCAT2/PSMA4 and CLTC ceRNA networks were linked to the prognosis of PDAC. In conclusion, NR2F1-AS1 overexpression was significantly associated with poor prognosis. NR2F1-AS1 functions as an endogenous RNA to construct a novel ceRNA network by competitively binding to miR-146a-5p/miR-877-5p, which may contribute to PDAC pathogenesis and could represent a promising diagnostic biomarker or potential novel therapeutic target in PDAC.

Cell-to-cell interaction analysis of prognostic ligand-receptor pairs in human pancreatic ductal adenocarcinoma

Cell-to-cell interactions (CCIs) through ligand-receptor (LR) pairs in the tumor microenvironment underlie the poor prognosis of pancreatic ductal adenocarcinoma (PDAC). However, there is scant knowledge of the association of CCIs with PDAC prognosis, which is critical to the identification of potential therapeutic candidates. Here, we sought to identify the LR pairs associated with PDAC patient prognosis by integrating survival analysis and single-cell CCI prediction. Via survival analysis using gene expression from cancer cohorts, we found 199 prognostic LR pairs. CCI prediction based on single-cell RNA-seq data revealed the enriched LR pairs associated with poor prognosis. Notably, the CCIs involved epithelial tumor cells, cancer-associated fibroblasts, and tumor-associated macrophages through integrin-related and ANXA1–FPR pairs. Finally, we determined that CCIs involving 33 poor-prognostic LR pairs were associated with tumor grade. Although the clinical implication of the set of LR pairs must be determined, our results may provide potential therapeutic targets in PDAC.

Circular RNA CircEYA3 induces energy production to promote pancreatic ductal adenocarcinoma progression through the miR-1294/c-Myc axis

BackgroundExtensive studies have demonstrated the pivotal roles of circular RNAs (circRNAs) in the occurrence and development of different human cancers. However, the expression and regulatory roles of circRNAs in pancreatic ductal adenocarcinoma (PDAC) are unclear.MethodsCircEYA3 was explored based on Gene Expression Omnibus (GEO) dataset analysis. qRT-PCR was applied to determine the expression of circRNAs, miRNAs and mRNAs in PDAC cells and tissues. The biological roles of circEYA3 in vitro and in vivo were determined by performing a series of functional experiments. Further, dual luciferase reporter, fluorescence in situ hybridization (FISH), RNA pull-down assays, and RNA immunoprecipitation (RIP) assays were used to confirm the interaction of circEYA3 with miR-1294.ResultsCircEYA3 was elevated in PDAC tissues and cells, and a higher level of circEYA3 was significantly associated with a poorer prognosis in patients with PDAC. Functionally, circEYA3 increased energy production via ATP synthesis to promote PDAC progression in vitro and in vivo. Mechanistically, circEYA3 functions as an endogenous miR-1294 sponge to elevate c-Myc expression, thus exerting its oncogenic functions.ConclusionCircEYA3 promotes the progression of PDAC through the miR-1294/c-Myc signalling axis, and circEYA3 may be an efficient molecular therapeutic target in PDAC.

CIRBP Knockdown Attenuates Tumourigenesis and Improves the Chemosensitivity of Pancreatic Cancer via the Downregulation of DYRK1B

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies worldwide with very limited treatment options. Cold-inducible RNA binding protein (CIRBP) plays promoting roles in several types of cancers, but its function remains unclear in PDAC. Here, we found that the expression of CIRBP was upregulated in PDAC tumor tissues and was significantly associated with poor prognosis. Knockdown of CIRBP in PANC-1 and SW1990 cells inhibited proliferation, migration and invasion in vitro and suppressed tumor growth in vivo. Moreover, CIRBP knockdown enhanced the antitumour effects of gemcitabine treatment in PANC-1 and SW1990 cells, whereas CIRBP overexpression exerted the opposite effects. Mechanistically, CIRBP promoted PDAC malignancy and chemoresistance via upregulation of dual-specificity tyrosine-Y-phosphorylation regulated kinase 1B (DYRK1B). Indeed, knockdown of CIRBP sensitized pancreatic tumors to gemcitabine treatment by diminishing DYRK1B expression and increasing the ratio of ERK/p38 activity. Our findings suggest that CIRBP overexpression facilitates PDAC progression and gemcitabine resistance by upregulating DYRK1B expression and inhibiting the ERK/p38 signaling pathway, highlighting CIRBP as a potential new therapeutic target for PDAC.