Therapeutic Target For Pancreatic Cancer Research Articles

Epigenetic reprogramming in pancreatic premalignancy and clinical implications.

Pancreatic cancer (PC) is the most lethal human cancer, with less than 10% 5-year survival. Pancreatic premalignancy is a genetic and epigenomic disease and is linked to PC initiation. Pancreatic premalignant lesions include pancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasm (IPMN), and mucinous cystic neoplasm (MCN), with pancreatic acinar-to-ductal metaplasia (ADM) as the major source of pancreatic premalignant lesions. Emerging evidence reveals that an epigenetic dysregulation is an early event in pancreatic tumorigenesis. The molecular mechanisms of epigenetic inheritance include chromatin remodeling; modifications in histone, DNA, and RNA; non-coding RNA expression; and alternative splicing of RNA. Changes in those epigenetic modifications contribute to the most notable alterations in chromatin structure and promoter accessibility, thus leading to the silence of tumor suppressor genes and/or activation of oncogenes. The expression profiles of various epigenetic molecules provide a promising opportunity for biomarker development for early diagnosis of PC and novel targeted treatment strategies. However, how the alterations in epigenetic regulatory machinery regulate epigenetic reprogramming in pancreatic premalignant lesions and the different stages of their initiation needs further investigation. This review will summarize the current knowledge of epigenetic reprogramming in pancreatic premalignant initiation and progression, and its clinical applications as detection and diagnostic biomarkers and therapeutic targets in PC.

Screening of Therapeutic Targets for Pancreatic Cancer by Bioinformatics Methods.

Pancreatic cancer (PC) has the lowest survival rate and the highest mortality rate among all cancers due to lack of effective treatments. The objective of the current study was to identify potential therapeutic targets in PC. Three transcriptome datasets, namely GSE62452, GSE46234, and GSE101448, were analyzed for differentially expressed genes (DEGs) between cancer and normal samples. Several bioinformatics methods, including functional analysis, pathway enrichment, hub genes, and drugs were used to screen therapeutic targets for PC. Fisher's exact test was used to analyze functional enrichments. To screen DEGs, the paired t-test was employed. The statistical significance was considered at p <0.05. Overall, 60 DEGs were detected. Functional enrichment analysis revealed enrichment of the DEGs in "multicellular organismal process", "metabolic process", "cell communication", and "enzyme regulator activity". Pathway analysis demonstrated that the DEGs were primarily related to "Glycolipid metabolism", "ECM-receptor interaction", and "pathways in cancer". Five hub genes were examined using the protein-protein interaction (PPI) network. Among these hub genes, 10 known drugs targeted to the CPA1 gene and CLPS gene were found. Overall, CPA1 and CLPS genes, as well as candidate drugs, may be useful for PC in the future.

Development of a basement membrane gene signature and identification of the potential candidate therapeutic targets for pancreatic cancer.

Pancreatic cancer is a deadly cancer with a poor prognosis. In light of mounting evidence that basement membrane genes (BMGs) play a role in the development of cancer, we sought to examine the prognostic importance and role of BMGs in pancreatic ductal adenocarcinoma (PDAC) patients. BMGs were obtained from previous top research studies. The clinical and messenger ribonucleic acid expression data were retrieved from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) data sets, respectively. Cox regression and least absolute shrinkage and selection operator (LASSO) regression analyses were used for the PDAC risk modeling and gene identification. The Kaplan-Meier method was used to compare outcomes between the low- and high-risk groups. Finally, we analyzed small-molecule drugs that could be used to target BMGs for treatment using the Enrichr data set and validated the function of the tubulointerstitial nephritis antigen (TINAG) in pancreatic cancer. We successfully constructed and validated a 7 BMG-based model to predict PDAC patient outcomes. Additionally, we discovered that 7 BMG-based model was an independent predictive factor for PDAC. According to our functional analysis, the majority of the signaling pathways enriched in BMGs were those connected to malignancy. Immune cell infiltration and immunological checkpoints were also linked to the BMG-based model. Further, we identified 5 small-molecule drugs that may be useful in treating PDAC patients. We also found that TINAG promoted cell proliferation in pancreatic cancer. Our study extended understandings of how BMGs work in PDAC. We identified a credible predictive biomarker for PDAC patients' survival.

Identification of EMT-related alternative splicing event of TMC7 to promote invasion and migration of pancreatic cancer.

Epithelial-to-mesenchymal transition (EMT) is tightly associated with the invasion and metastasis of pancreatic cancer with rapid progression and poor prognosis. Notably, gene alternative splicing (AS) event plays a critical role in regulating the progression of pancreatic cancer. Therefore, this study aims to identify the EMT-related AS event in pancreatic cancer. The EMT-related gene sets, transcriptomes, and matched clinical data were obtained from the MSigDB, The Cancer Genome Atlas (TCGA), International Cancer Genome Consortium (ICGC), and Gene Expression Omnibus (GEO) databases. Key gene AS events associated with liver metastasis were identified by prognostic analysis, gene set variation analysis (GSVA), and correlation analysis in pancreatic cancer. The cell line and organoid model was constructed to evaluate these key gene AS events in regulating pancreatic cancer in vitro. Furthermore, we established an EMT-related gene set consisting of 13 genes by prognostic analysis, the role of which was validated in two other databases. Finally, the human pancreatic cancer tissue and organoid model was used to evaluate the correlation between the enrichment of this gene set and liver metastasis. Prognostic analysis and correlation analysis revealed that eight AS events were closely associated with the prognosis of pancreatic cancer. Furthermore, the expression of TMC7 and CHECK1 AS events was increased in the metastatic lesions of the human tissue and organoid model. Additionally, the knockdown of exon 17 of TMC7 significantly inhibited the proliferation, invasion, and migration of pancreatic cancer cells in 2D and 3D cell experiments. Finally, the expression of exon 17 of TMC17 exhibited a significant correlation with the poor prognosis in pancreatic ductal adenocarcinoma (PDAC). The AS events of TMC7 and CHECK1 were associated with liver metastasis in pancreatic cancer. Moreover, exon 17 of TMC7 could be a potential therapeutic target in pancreatic cancer.

Integrative structural and functional analysis of human malic enzyme 3: A potential therapeutic target for pancreatic cancer

Malic enzymes (ME1, ME2, and ME3) are involved in cellular energy regulation, redox homeostasis, and biosynthetic processes, through the production of pyruvate and reducing agent NAD(P)H. Recent studies have implicated the third and least well-characterized isoform, mitochondrial NADP+-dependent malic enzyme 3 (ME3), as a therapeutic target for pancreatic cancers. Here, we utilized an integrated structure approach to determine the structures of ME3 in various ligand-binding states at near-atomic resolutions. ME3 is captured in the open form existing as a stable tetramer and its dynamic Domain C is critical for activity. Catalytic assay results reveal that ME3 is a non-allosteric enzyme and does not require modulators for activity while structural analysis suggests that the inner stability of ME3 Domain A relative to ME2 disables allostery in ME3. With structural information available for all three malic enzymes, the foundation has been laid to understand the structural and biochemical differences of these enzymes and could aid in the development of specific malic enzyme small molecule drugs.

MicroRNA-543 controls pancreatic cancer development by LINC00847-microRNA-543-STK31 axis.

Pancreatic cancer (PC) is one of the most malignant cancers of the gastrointestinal tract. However, the study of targeted therapy research in PC is not very thorough. Therefore, targeted molecular markers are needed to aid in the diagnosis and treatment of PC. In our research, we investigated the biological functions and molecular mechanism of microRNA-543 in PC. Western blotting (WB) and quantitative real-time polymerase chain reaction (qRT-PCR) were performed to analyze the transcription and protein expression of microRNA-543, Serine/threonine kinase 31 (STK31), and LINC00847 in BxPC-3 and PANC-1 cells. Subsequently, Cell Counting Kit-8 (CCK-8), Transwell, colony formation, and flow cytometry (FCM) assays were utilized to evaluate cell growth, migration, invasion, and apoptosis. WB and fluorescence in-situ hybridization (FISH) were used to evaluate the epithelial-mesenchymal transition (EMT) process and subcellular localization. RNA immunoprecipitation (RIP), double luciferase reporter, and RNA-pull down assays were performed to determine the targeting relationship between microRNA-543 and STK31 or microRNA-543 and LINC00847. While microRNA-543 expression was discovered to be low in PC, LINC00847 and STK31 were overexpressed at significant levels. MicroRNA-543 knockdown dramatically increased PC cell growth, invasion, metastasis, and EMT, as well as decreased apoptosis in functional studies. Furthermore, microRNA-543 and STK31 were found to be mutual targets. LINC00847 acted as a molecular sponge for microRNA-543 and a competitive endogenous RNA (ceRNA) for STK31, thereby increasing STK-31 transcription. Our results suggest that microRNA-543, through the LINC00847/microRNA-543/STK31 axis, plays a role in the development of PC as a tumor suppressor. As a result, microRNA-543 may prove to be an effective diagnostic and therapeutic target for PC.

Roles of circular RNAs in the pathogenesis and treatment of pancreatic cancer.

Circular RNAs are single-stranded RNAs with a covalently closed structure formed by the process of back-splicing. Aberrant expression of circular RNAs contributes to the pathogenesis of a wide range of cancers. Pancreatic cancer is one of the most lethal cancers due to diagnostic difficulties and limited therapeutic options. Circular RNAs are emerging as novel diagnostic biomarkers and therapeutic targets for pancreatic cancer. Moreover, recent advances in the therapeutic application of engineered circular RNAs have provided a promising approach to overcoming pancreatic cancer. This review discusses the roles of circular RNAs in the pathogenesis of pancreatic cancer and in potential treatment applications and their usefulness as diagnostic biomarkers.

Glycogen Synthase Kinase 3β: A True Foe in Pancreatic Cancer.

Glycogen synthase kinase 3 beta (GSK-3β) is a serine/threonine protein kinase involved in multiple normal and pathological cell functions, including cell signalling and metabolism. GSK-3β is highly expressed in the onset and progression of multiple cancers with strong involvement in the regulation of proliferation, apoptosis, and chemoresistance. Multiple studies showed pro- and anti-cancer roles of GSK-3β creating confusion about the benefit of targeting GSK-3β for treating cancer. In this mini-review, we focus on the role of GSK-3β in pancreatic cancer. We demonstrate that the proposed anti-cancer roles of GSK-3β are not relevant to pancreatic cancer, and we argue why GSK-3β is, indeed, a very promising therapeutic target in pancreatic cancer.

Abstract B004: sCD-3BP: An MCT-1-“gated” therapeutic for pancreatic adenocarcinoma

Abstract Metabolic reprogramming is a hallmark of Pancreatic Ductal Adenocarcinomas (PDAC) and offers unique opportunities for therapeutic development. TCGA datasets and pancreatic tissue microarrays reveal that nearly 30% of PDACs exhibit a marked overexpression of Monocarboxylate Transporter 1 (MCT-1), a known lactate/pyruvate transporter. In addition, several clinical studies have correlated MCT-1 expression to poor patient prognosis in other cancers and potential resistance to therapies in PDAC, making MCT-1 an intriguing therapeutic target for pancreatic cancer. In this study, we leverage 3-Bromopyruvate (3BP), a cytotoxic pyruvate analog, to target MCT-1 overexpressing PDACs and optimize it for systemic delivery. First, we establish that the sensitivity of PDAC cells to 3BP correlates to MCT-1 expression. In vitro studies with a panel of pancreatic cancer cell lines highlight that the cytotoxicity of 3BP is limited to PDAC cells with elevated MCT-1 and the mode of action of 3BP is distinctly different from AZD-3965, an MCT-1 inhibitor under clinical investigation. We demonstrate that 3BP exerts its effect on PDAC cells using MCT-1 as gate to enter a cell and then induce cytotoxicity. While 3BP is considered promising, poor serum stability, pharmacokinetics, and excessive in vivo toxicity have hampered its clinical development. We show here, a novel formulation where 3BP is entrapped inside a cyclodextrin cage (sCD-3BP) stabilizes 3BP in vivo, retains its MCT-1 specific activity, and delivers significantly more drug to the tumor with a single dose. Additionally, we show that even short exposures of sCD-3BP are adequate for induction of cell death when compared to current standard-of-care therapeutics such as gemcitabine and components of FOLFIRINOX. Finally, we test our MCT-1 gated approach in multiple in vivo models of pancreatic cancer: an orthotopic pancreatic cancer cell line model and two patient-derived orthotopic xenografts (PDoX) models originating from a primary pancreatic and a metastatic site. Arguably more clinically relevant, the PDoX models used in our study closely mimic clinical features of donor disease, causing significant metastasis to lung and liver, marked invasion into the pancreas, and development of duct-like structures within the tumor. In these models, sCD-3BP significantly reduces pancreatic cancer growth and metastatic spread. In summary, we show that intravenous administration of sCD-3BP is safe, causes no damage to normal tissue and effectively suppresses PDAC tumor growth and reduces metastatic burden. In addition, elucidating the mechanism of action of 3BP allows us to identify potential candidates for this therapy. Our study demonstrates that sCD-3BP can be a powerful therapeutic tool against MCT-1 overexpressed PDACs and present a strong rationale for future human clinical trials. Citation Format: Surojit Sur, Jordina Rincon-Toroella, Marco Dal Molin, Kathleen Gabrielson, Chetan Bettegowda, Shibin Zhou, Ken Kinzler, Bert Vogelstein. sCD-3BP: An MCT-1-“gated” therapeutic for pancreatic adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B004.

Abstract B080: Disruption of ADAM17-dependent cellular crosstalk inhibits tumor progression of pancreatic ductal adenocarcinoma

Abstract Activation of cellular signaling pathways by crosstalk between tumor cells and their microenvironment is an essential mechanism supporting pancreatic carcinogenesis. In this study, we aim to disrupt cellular signaling pathways by targeting ADAM17 (a disintegrin and metalloprotease 17). ADAM17 is a membrane bound enzyme which cleaves cell surface proteins. Its function is closely linked with autocrine and paracrine signaling of immunomodulation as well as activation of EGFR, which is a central molecule for pancreatic tumorigenesis. To investigate whether EGFR is activated via a paracrine manner from macrophages, the most abundant immune-related stromal cells in pancreas cancers, we generated a pancreatic tumor mouse model with ADAM17 deletion in myeloid cells by using a dual recombinase strategy. We observed that lack of ADAM17 in the myeloid cells resulted in a delay of acinar cell transformation and an associated decrease in EGFR activation. To further examine the tumor supportive role of ADAM17, systemic inhibition of ADAM17 using anti-ADAM17 antibody, MEDI3622, was tested in orthotopic tumor bearing mice. Systemic blockade of ADAM17 significantly reduced tumor burden and suppressed activation of EGFR and STAT3, which are associated with two pro-tumoral signaling pathways. In addition, we found an elevated level of CCL21 in the MEDI3622-treated tumors resulting in increased tumor infiltration by dendritic cells and cytotoxic T cells as well as low infiltration of G-MDSC (granulocytic myeloid-derived suppressor cells). These results demonstrate a pronounced anti-tumor effect by ADAM17 blockade and indicate ADAM17 as a therapeutic target of pancreatic cancer. Citation Format: Hui-Ju Wen, Jacee Moore, Erick Davis, Daniel Long, Justin Lee, Brian Devorkin, Howard Crawford. Disruption of ADAM17-dependent cellular crosstalk inhibits tumor progression of pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B080.

Abstract B017: MICAL2 promotes pancreatic cancer growth and metastasis independent of MRTF-A signaling

Abstract Introduction: Pancreatic ductal adenocarcinoma (PDAC) is a lethal cancer in large part due to its propensity for early metastasis. We used ChIP-seq to identify differentially tagged super-enhancer associated genes in PDAC and identified MICAL2 as a gene of interest. MICAL (molecule interacting with CasL) proteins are flavin monooyxgenases that induce actin depolymerization. MICAL2 canonically modulates nuclear actin to regulate SRF/MRTF-A (myocardin related transcription factor) mediated transcription to drive EMT (epithelial-mesenchymal transition) and fibrosis. In this study, we sought to determine the impact of MICAL2 on PDAC progression and its dependence on SRF/MRTF-A signaling. Methods: Studies were performed in human and murine PDAC models. MICAL2 and MRTF-A were knocked down with shRNA and gene expression quantitated with qPCR. In vitro cell viability was assessed by MTT colorimetric assay. Cell migration was tested with in vitro wound scratch assays. Cell cycle analysis was done with flow cytometry-based DNA content measurement. Subcutaneous, orthotopic, and intrasplenic injections of PDAC cells were performed to assess in vivo growth and metastasis. Protein expression was measured with Western blotting. Student’s t-test was used to confirm statistical significance of experimental results. Results: In human PDAC cell lines, MICAL2 knockdown decreased cell viability, reduced cell migration and wound healing, and induced cell cycle arrest at G0/G1. MICAL2 inhibition was associated with decreased p-AKT, c-Myc, and increased p27 by Western blot. Orthotopic and subcutaneous injections of KPC46 shMICAL2 cells were performed in syngeneic mice; orthotopic injections of shMICAL2 cells led to decreased tumor growth compared to control (0.26 gm vs. 1 gm, p = 0.008), not observed with shMRTF-A (1.032 gm vs. 1 gm, p = 0.95). Subcutaneous injections of MICAL2 knockdown cells led to no tumor growth; injections of MRTF-A knockdown cells again led to comparable tumor growth as control (3.02 gm vs. 1.72 gm, p = 0.24). GSEA (Gene Set Enrichment Analysis) of RNAseq data demonstrated a correlation between MICAL2 knockdown and downregulation of Hallmark EMT pathways. Intrasplenic injection studies in syngeneic mice revealed grossly decreased liver metastases after intrasplenic injection of shMRTF-A cells, with total abrogation of metastases after injection of shMICAL2 cells. Conclusions: MICAL2 promotes pancreatic cancer cell growth and metastasis. While MICAL2’s effect on metastasis appears largely dependent on SRF/MRTF-A, tumor growth appears to be MRTF-A independent, suggesting putative novel functions of MICAL2. Given its potentially targetable enzymatic domain and important role in promoting cell growth in vitro and tumor progression and metastasis in vivo, MICAL2 holds promise as a novel tractable therapeutic target in pancreatic cancer. Citation Format: Sohini Khan, Shweta Sharma, Divya Sood, Bharti Garg, Dawn Jaquish, Evangeline Mose, Edgar Esparza, Herve Tiriac, Andrew M. Lowy. MICAL2 promotes pancreatic cancer growth and metastasis independent of MRTF-A signaling [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B017.

Functional metabolomics revealed the dual-activation of cAMP-AMP axis is a novel therapeutic target of pancreatic cancer

Pancreatic cancer (PC) is one of the most malignant cancers, owing to extremely high aggressiveness and mortality. Yet, this condition currently incurs widely drug resistance and therapeutic deficiency. In this study, we proposed a novel functional metabolomics strategy as Spatial Temporal Operative Real Metabolomics (STORM) to identify the determinant functional metabolites in a dynamic and visualized pattern whose level changes are mechanistically associated with therapeutic efficiency of gemcitabine against PC. Integrating quantitative analysis and spatial-visualization characterization of functional metabolites in vivo, we identified that the AMP-cAMP axis was a novel therapeutic target of PC to intermediate therapeutic efficiency of gemcitabine. Gemcitabine could induce the dual accumulation of cyclic AMP (cAMP) and AMP in tumor tissues. Quantitative analysis of associated biosynthetic enzymes and genes revealed that two independent intracellular ATP derived biosynthetic pathways to promote the dual activation of AMP-cAMP axis in a lower-level energetic environment. Then, gemcitabine induced the dual accumulation of AMP and cAMP can separately activate signaling pathways of AMPK and PKA, leading to the inhibition of tumor growth by the upregulation of the downstream tumor suppressor GADD45A. Collectively, our new STORM strategy was the first time to identify novel target of PC from a metabolic perspective as the dual activation of AMP-cAMP axis induced by gemcitabine can efficiently suppress PC tumor growth. In addition, such discovery has the capability to lower drug resistance of gemcitabine by specifically interacting with novel target, contributing to the improvement of therapeutic efficiency.

Identification of MYEOV-Associated Gene Network as a Potential Therapeutic Target in Pancreatic Cancer.

The molecular mechanism that promotes pancreatic cancer remains unclear, so it is important to find the molecular network of important genes related to pancreatic cancer. To find the key molecule of pancreatic cancer, differential gene expression analyses were analyzed by the Deseq2 package, edgeR package, and limma-voom package, respectively. Pancreatic cancer survival-related genes were analyzed by COX survival analysis. Finally, we integrated the results to obtain the significantly differentially expressed gene, MYEOV (myeloma overexpressed gene), most strongly related to survival in pancreatic cancer. Experimental verification by qRT-PCR confirmed that transcription levels of MYEOV mRNA markedly increased in pancreatic cancer cells relative to normal human pancreatic ductal epithelial cells (HPDE). Through the comprehensive analysis of multiple databases, we constructed a molecular network centered on MYEOV and found specific links between molecules in this network and tumor-associated immune cells. It was noted that MYEOV could serve as a ceRNA by producing molecular sponging effects on hsa-miR-103a-3p and hsa-miR-107, thus affecting the role of GPRC5A, SERPINB5, EGFR, KRAS, EIF4G2, and PDCD4 on pancreatic cancer progression. Besides, we also identified that infiltrated immune cells are potential mediators for the molecules in the MYEOV-related network to promote pancreatic cancer progression. It is the first report to focus on the possibility that MYEOV may act as a competing endogenous RNA (ceRNA) to form an interactive network with some pancreatic cancer-related genes such as KRAS and serve as a key therapeutic target of pancreatic cancer treatment.

MACC1 promotes pancreatic cancer metastasis by interacting with the EMT regulator SNAI1

Metastasis is the dominant cause of cancer-related mortality. Metastasis-associated with colon cancer protein 1 (MACC1) has been proven to play a critical role in cancer metastasis. However, the prometastatic role of MACC1 in regulating the pancreatic cancer (PC) metastatic phenotype remains elusive. Here, we report that MACC1 is highly expressed in The Cancer Genome Atlas (TCGA) and tissue microarray (TMA) and identified as a good indicator for poor prognosis. Overexpression or knockdown of MACC1 in PC cells correspondingly promoted or inhibited pancreatic cancer cell migration and invasion in a MET proto-oncogene receptor tyrosine kinase (MET)-independent manner. Notably, knockdown of MACC1 in PC cells markedly decreased the liver metastatic lesions in a liver metastasis model. Mechanistically, MACC1 binds to the epithelial-mesenchymal transition (EMT) regulator snail family transcriptional repressor 1 (SNAI1) to drive EMT via upregulating the transcriptional activity of SNAI1, leading to the transactivation of fibronectin 1 (FN1) and the trans-repression of cadherin 1 (CDH1). Collectively, our results unveil a new mechanism by which MACC1 drives pancreatic cancer cell metastasis and suggest that the MACC1-SNAI1 complex-mediated mesenchymal transition may be a therapeutic target in pancreatic cancer.

Hypoxia-induced circRNF13 promotes the progression and glycolysis of pancreatic cancer

Pancreatic cancer (PC) is one of the most malignant tumors. Rapid progression and distant metastasis are the main causes of patient death. Hypoxia is a hallmark of multiple cancers and is involved in tumor biology. However, little is known about the roles of circRNAs in glycolysis and hypoxia-mediated progression of PC. Here, the expression pattern of hypoxia-related circRNAs was analyzed using RNA sequencing. A unique circRNA termed circRNF13 was found to be upregulated in PC tissues and may be a potential prognostic indicator. HIF-1α and EIF4A3 are involved in regulating the biogenesis of circRNF13. Furthermore, circRNF13 was validated to exert a stimulative effect on cell proliferation, angiogenesis, invasion and glycolysis. Importantly, we found that circRNF13 promoted PDK3 levels by acting as a miR-654-3p sponge, thus promoting the PC malignant process. Collectively, our results reveal that hypoxia-induced circRNF13 mediated by HIF-1α and EIF4A3 promotes tumor progression and glycolysis in PC, indicating the potential of circRNF13 as a prognostic biomarker and therapeutic target for PC.

Retinoic acid receptor gamma is required for proliferation of pancreatic cancer cells.

Despite the expectation that retinoic acid receptor could be the potential therapeutic targets for pancreatic cancers, there has been the lack of information about the role and the impact of retinoic acid receptor gamma (RARγ, RARG) on pancreatic cancer, unlike other two RARs. Herein, we applied TCGA and GEO database to show that the expression and prognosis of RARG is closely related to pancreatic cancer, which demonstrates that RARG is commonly overexpressed in human pancreatic cancer and is an independent diagnostic marker predicting the poor prognosis of pancreatic cancer patients. In addition, we demonstrated that the reduction in the expression of RARG in human pancreatic cancer cells dramatically suppress their proliferation and tumor growth in vivo, partially attributable to the downregulation of tumor-supporting biological processes such as cell proliferation, antiapoptosis and metabolism and the decreased expression of various oncogenes like MYC and STAT3. Mechanistically, RARG binds on the promoters of MYC, STAT3, and SLC2A1 which is distinguished from well-known conventionalRetinotic acid response elements (RAREs) and that the binding is likely to be responsible for the epigenetic activation in the level of chromatin, assessed by the measurement of deposition of the gene activation marker histone H3 K27 acetylation (H3K27ac) using ChIP-qPCR. In this study, we reveal that RARG plays important role in the tumorigenesis of pancreatic cancer and represents new therapeutic targets for human pancreatic cancer.

Leveraging the Structure of DNAJA1 to Discover Novel Potential Pancreatic Cancer Therapies.

Pancreatic cancer remains one of the deadliest forms of cancer with a 5-year survival rate of only 11%. Difficult diagnosis and limited treatment options are the major causes of the poor outcome for pancreatic cancer. The human protein DNAJA1 has been proposed as a potential therapeutic target for pancreatic cancer, but its cellular and biological functions remain unclear. Previous studies have suggested that DNAJA1′s cellular activity may be dependent upon its protein binding partners. To further investigate this assertion, the first 107 amino acid structures of DNAJA1 were solved by NMR, which includes the classical J-domain and its associated linker region that is proposed to be vital to DNAJA1 functionality. The DNAJA1 NMR structure was then used to identify both protein and ligand binding sites and potential binding partners that may suggest the intracellular roles of DNAJA1. Virtual drug screenings followed by NMR and isothermal titration calorimetry identified 5 drug-like compounds that bind to two different sites on DNAJA1. A pull-down assay identified 8 potentially novel protein binding partners of DNAJA1. These proteins in conjunction with our previously published metabolomics study support a vital role for DNAJA1 in cellular oncogenesis and pancreatic cancer.

Apolipoprotein E2 inhibits mitochondrial apoptosis in pancreatic cancer cells through ERK1/2/CREB/BCL-2 signaling

BackgroundApolipoprotein E2 (ApoE2) is a pleiotropic protein that influences several aspects of cancer metabolism and development. Evading apoptosis is a vital factor for facilitating cancer cell growth. However, the role and mechanism of ApoE2 in regulating cell apoptosis of pancreatic cancer remain unclear. MethodsIn this study, we firstly detected the mRNA and protein expressions of ApoE2 in PANC-1 and Capan-2 cells by real-time polymerase chain reaction and Western blotting. We then performed TUNEL and flow cytometric analyses to explore the role of recombinant human ApoE2, pCMV6-ApoE2 and siApoE2 in the apoptosis of PANC-1 and Capan-2 cells. Furthermore, we investigated the molecular mechanism through which ApoE2 affected apoptosis in PANC-1 cells using immunofluorescence, immunoprecipitation, Western blotting and co-immunoprecipitation analysis. ResultsApoE2 phosphorylated ERK1/2 and inhibited pancreatic cancer cell apoptosis. In addition, our data showed that ApoE2/ERK1/2 altered the expression and mitochondrial localization of BCL-2 via activating CREB. ApoE2/ERK1/2/CREB also increased the total BCL-2/BAX ratio, inhibited the opening of the mitochondrial permeability transition pore and the depolarization of mitochondrial transmembrane potential, blocked the leakage of cytochrome-c and the formation of the apoptosome, and consequently, suppressed mitochondrial apoptosis. ConclusionsApoE2 regulates the mitochondrial localization and expression of BCL-2 through the activation of the ERK1/2/CREB signaling cascade to evade the mitochondrial apoptosis of pancreatic cancer cells. ApoE2 may be a distinct prognostic marker and a potential therapeutic target for pancreatic cancer.

A LETM2-Regulated PI3K-Akt Signaling Axis Reveals a Prognostic and Therapeutic Target in Pancreatic Cancer.

Simple SummaryLEMT2 was a newly discovered protein-encoding gene with little cancer research and an unclear mechanism. This study aimed to illustrate LETM2 as the crucial oncogene for tumor progression in pancreatic ductal adenocarcinoma (PDAC). We analyzed the expression level and prognostic value of LETM2 in multiple cancers using pan-cancer analysis and found that the LETM2 expression was the most significantly related to the dismal prognosis of PDAC. Immunohistochemical analyses showed that high LETM2 expression was correlated with poor outcomes of PDAC. In in vitro and in vivo experiments, LETM2 knockdown significantly inhibited tumor proliferation and metastasis, while LETM2 overexpression exerted the opposite effects. Then, we suggested that LETM2 may facilitate tumor progression by activating downstream PI3K-Akt signaling pathway in PDAC. In conclusion, the study enhanced our understanding of the LETM2-regulated PI3K-Akt signaling axis served as a prognostic and therapeutic target of pancreatic cancer.Pancreatic ductal adenocarcinoma (PDAC) is one of the highest mortalities malignant tumors, which is characterized by difficult diagnosis, rapid progression and high recurrence rate. Nevertheless, PDAC responds poorly to conventional therapies, which highlights the urgency to identify novel prognostic and therapeutic targets. LEMT2 was a newly discovered protein-encoding gene with little cancer research and an unclear mechanism. Thus, this study aimed to illustrate LETM2 as the crucial oncogene for tumor progression in PDAC. In this study, we analyzed the expression level and prognostic value of LETM2 in multiple cancers using pan-cancer analysis. The analyses based on the TCGA-GTEx dataset indicated that the LETM2 expression was obviously elevated in several cancers, and it was the most significantly related to the dismal prognosis of PDAC. Subsequently, we demonstrated the functional role and mechanism of LETM2 by clinical sample evaluation, and in in vitro and in vivo experiments. Immunohistochemical analyses showed that high expression of LETM2 was correlated with poor outcomes of PDAC. Moreover, we demonstrated that LETM2 knockdown significantly inhibited tumor proliferation and metastasis, and promoted cell apoptosis, while LETM2 overexpression exerted the opposite effects. Finally, the impairment caused by LETM2-knockdown could be recovered via excitation of the PI3k-Akt pathway in vitro and in vivo animal models, which suggested that LETM2 could activate the downstream PI3K-Akt pathway to participate in PDAC progression. In conclusion, the study enhanced our understanding of LETM2 as an oncogene hallmark of PDAC. LETM2 may facilitate tumor progression by activating the PI3K-Akt signaling pathway, which provides potential targets for the diagnosis, treatment, and prognosis of pancreatic cancer.

Senescent Human Pancreatic Stellate Cells Secrete CXCR2 Agonist CXCLs to Promote Proliferation and Migration of Human Pancreatic Cancer AsPC-1 and MIAPaCa-2 Cell Lines.

Interactions between pancreatic cancer cells and pancreatic stellate cells (PSCs) play an important role in the progression of pancreatic cancer. Recent studies have shown that cellular senescence and senescence-associated secretory phenotype factors play roles in the progression of cancer. This study aimed to clarify the effects of senescence-induced PSCs on pancreatic cancer cells. Senescence was induced in primary-cultured human PSCs (hPSCs) through treatment with hydrogen peroxide or gemcitabine. Microarray and Gene Ontology analyses showed the alterations in genes and pathways related to cellular senescence and senescence-associated secretory phenotype factors, including the upregulation of C-X-C motif chemokine ligand (CXCL)-1, CXCL2, and CXCL3 through the induction of senescence in hPSCs. Conditioned media of senescent hPSCs increased the proliferation—as found in an assessment with a BrdU incorporation assay—and migration—as found in an assessment with wound-healing and two-chamber assays—of pancreatic cancer AsPC-1 and MIAPaca-2 cell lines. SB225002, a selective CXCR2 antagonist, and SCH-527123, a CXCR1/CXCR2 antagonist, attenuated the effects of conditioned media of senescent hPSCs on the proliferation and migration of pancreatic cancer cells. These results suggest a role of CXCLs as senescence-associated secretory phenotype factors in the interaction between senescent hPSCs and pancreatic cancer cells. Senescent PSCs might be novel therapeutic targets for pancreatic cancer.