A Nutrient-Deficient Microenvironment Facilitates Ferroptosis Resistance via the FAM60A-PPAR Axis in Pancreatic Ductal Adenocarcinoma.

Ferroptosis, a nonapoptotic form of cell death, is an emerging potential therapeutic target for various diseases, including cancer. However, the role of ferroptosis in pancreatic cancer remains poorly understood. Pancreatic ductal adenocarcinoma (PDAC) is characterized by a poor prognosis and chemotherapy resistance, attributed to its high Kirsten rats arcomaviral oncogene homolog mutation rate and severe nutritional deficits resulting from a dense stroma. Several studies have linked rat sarcoma (RAS) mutations to ferroptosis, suggesting that inducing ferroptosis may be an effective strategy against oncogenic RAS-bearing tumors. We investigated the role of Family With Sequence Similarity 60 Member A (FAM60A) in this study, a protein closely associated with a poor prognosis and highly expressed in PDAC and tumor tissue from KrasG12D/+;Trp53R172H/+; Pdx1-Cre mice, in regulating ferroptosis, tumor growth, and gemcitabine sensitivity in vitro and in vivo. Our results demonstrate that FAM60A regulates 3 essential metabolic enzymes, ACSL1/4 and GPX4, to protect PDAC cells from ferroptosis. Furthermore, we found that YY1 transcriptionally regulates FAM60A expression by promoting its transcription, and the Hippo-YY1 pathway is restricted in the low-amino-acid milieu in the context of nutrient deprivation, leading to downstream suppression of peroxisome proliferator-activated receptor and ACSL1/4 and activation of GPX4 pathways. Importantly, FAM60A knockdown sensitized PDAC cells to gemcitabine treatment. A new understanding of FAM60A transcriptional regulation pattern in PDAC and its dual function in ferroptosis reliever and chemotherapy resistance is provided by our study. Targeting FAM60A may therefore offer a promising therapeutic approach for PDAC by simultaneously addressing 2 major features of the disease (high RAS mutation rate and tumor microenvironment nutrient deficiency) and preventing tumor cell metabolic adaptation.

Prediction of immune infiltration and prognosis for patients with cholangiocarcinoma based on a cuproptosis-related lncRNA signature.

Objective: Cholangiocarcinoma (CHOL) is a malignant disease that affects the digestive tract, and it is characterized by a poor prognosis. This research sought to explore the involvement of cuproptosis-related lncRNAs (CRLs) in the prognostic prediction and immune infiltration of cholangiocarcinoma. Methods: The expression profiles and clinical data of CHOL patients were acquired from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, and CRLs were defined via co-expression analysis. Two molecular clusters distinguished by cuproptosis-related genes (CRGs) were produced. Then a risk signature consisted by four CRLs was formed, and all samples were separated into low- and high-risk groups using a risk score. Kaplan-Meier survival analysis, principal component analysis, differentially expressed analysis, immune cell infiltration analysis, and sensitivities analysis of chemotherapy drugs were conducted between the two groups. Simultaneously, the expression values of four lncRNAs confirmed by real-time PCR in our own 20 CHOL samples were brought into the risk model. Results: The CHOL samples could be differentiated into two molecular clusters, which displayed contrasting survival times. Additionally, patients with higher risk scores had significantly worse prognosis compared to those in the low-risk group. Furthermore, both immune infiltration and enrichment analysis revealed significant discrepancies in the tumor immune microenvironment (TIME) between different risk groups. Moreover, the predictive power and the correlation with CA19-9 and CEA of risk signature were validated in our own samples. Conclusion: We developed a risk signature which could serve as an independent prognostic factor and offer a promising prediction for not only prognosis but also TIME in CHOL patients.

Analysis of cuproptosis-related lncRNA signature for predicting prognosis and tumor immune microenvironment in pancreatic cancer.

Pancreatic cancer (PC) is a highly malignant digestive tract tumor, with a dismal 5-year survival rate. Recently, cuproptosis was found to be copper-dependent cell death. This work aims to establish a cuproptosis-related lncRNA signature which could predict the prognosis of PC patients and help clinical decision-making. Firstly, cuproptosis-related lncRNAs were identified in the TCGA-PAAD database. Next, a cuproptosis-related lncRNA signature based on five lncRNAs was established. Besides, the ICGC cohort and our samples from 30 PC patients served as external validation groups to verify the predictive power of the risk signature. Then, the expression of CASC8 was verified in PC samples, scRNA-seq dataset CRA001160, and PC cell lines. The correlation between CASC8 and cuproptosis-related genes was validated by Real-Time PCR. Additionally, the roles of CASC8 in PC progression and immune microenvironment characterization were explored by loss-of-function assay. As showed in the results, the prognosis of patients with higher risk scores was prominently worse than that with lower risk scores. Real-Time PCR and single cell analysis suggested that CASC8 was highly expressed in pancreatic cancer and related to cuproptosis. Additionally, gene inhibition of CASC8 impacted the proliferation, apoptosis and migration of PC cells. Furthermore, CASC8 was demonstrated to impact the expression of CD274 and several chemokines, and serve as a key indicator in tumor immune microenvironment characterization. In conclusion, the cuproptosis-related lncRNA signature could provide valuable indications for the prognosis of PC patients, and CASC8 was a candidate biomarker for not only predicting the progression of PC patients but also their antitumor immune responses.

ADAMTS12 promotes migration and epithelial-mesenchymal transition and predicts poor prognosis for pancreatic cancer.

BACKGROUND: ADAMTS (a disintegrin and metalloproteinase with thrombospondin-like motifs) family, a group of extracellular multifunctional enzymes, has been proven to play a pivotal role in the tumor. In pancreatic cancer, the role and mechanism of this family remain unclear. The present study aimed to figure out the hub gene of ADAMTSs and explore the exact roles in the prognosis and biological functions in pancreatic ductal adenocarcinoma (PDAC). METHODS: We used several databases to analyze the ADAMTS family and then screen out the hub genes. The expression of ADAMTS12 in 106 pairs of PDAC tumors and adjacent normal tissues was examined by immunohistochemistry, and its correlations with clinical parameters were further analyzed. The impacts of ADAMTS12 on the migration of PDAC cells were predicted by gene set enrichment analysis and confirmed by transwell assays. The potential impacts of ADAMTS12 on the epithelial-mesenchymal transition (EMT) were identified by database analysis and experimental proof of real-time quantitative polymerase chain reaction (qPCR) and Western blotting. RESULTS: Our study found that ADAMTS12 was a crucial gene in PDAC, and it was highly expressed in tumor tissues when compared to that in the adjacent tissues. ADATMS12 had predictive value of a poor prognosis for PDAC. The elevation of ADAMTS12 was parallel to the progression of PDAC. Inhibition of ADAMTS12 suppressed the migration of PDAC cells and interfered with the process of EMT. CONCLUSIONS: ADAMTS12 is a crucial member of ADAMTSs in PDAC and a predictor of poor prognosis. Additionally, based on its impacts on migration and metastasis in PDAC and the relationship with EMT, ADAMTS12 plays a role of an oncogene in PDAC and may be a promising target for treatment.

Immunosuppression, immune escape, and immunotherapy in pancreatic cancer: focused on the tumor microenvironment.

Pancreatic ductal adenocarcinoma (PDAC), the most common type of pancreatic cancer, is characterized by poor treatment response and low survival time. The current clinical treatment for advanced PDAC is still not effective. In recent years, the research and application of immunotherapy have developed rapidly and achieved substantial results in many malignant tumors. However, the translational application in PDAC is still far from satisfactory and needs to be developed urgently. To carry out the study of immunotherapy, it is necessary to fully decipher the immune characteristics of PDAC. This review summarizes the recent progress of the tumor microenvironment (TME) of PDAC and highlights its link with immunotherapy. We describe the molecular cues and corresponding intervention methods, collate several promising targets and progress worthy of further study, and put forward the importance of integrated immunotherapy to provide ideas for future research of TME and immunotherapy of PDAC.

IRAK2-NF-κB signaling promotes glycolysis-dependent tumor growth in pancreatic cancer.

BACKGROUND: Metabolic reprogramming has emerged as a core hallmark of cancer, and cancer metabolism has long been equated with aerobic glycolysis. Moreover, hypoxia and the hypovascular tumor microenvironment (TME) are major hallmarks of pancreatic ductal adenocarcinoma (PDAC), in which glycolysis is imperative for tumor cell survival and proliferation. Here, we explored the impact of interleukin 1 receptor-associated kinase 2 (IRAK2) on the biological behavior of PDAC and investigated the underlying mechanism. METHODS: The expression pattern and clinical relevance of IRAK2 was determined in GEO, TCGA and Ren Ji datasets. Loss-of-function and gain-of-function studies were employed to investigate the cellular functions of IRAK2 in vitro and in vivo. Gene set enrichment analysis, Seahorse metabolic analysis, immunohistochemistry and Western blot were applied to reveal the underlying molecular mechanisms. RESULTS: We found that IRAK2 is highly expressed in PDAC patient samples and is related to a poor prognosis. IRAK2 knockdown led to a significant impairment of PDAC cell proliferation via an aberrant Warburg effect. Opposite results were obtained after exogenous IRAK2 overexpression. Mechanistically, we found that IRAK2 is critical for sustaining the activation of transcription factors such as those of the nuclear factor-κB (NF-κB) family, which have increasingly been recognized as crucial players in many steps of cancer initiation and progression. Treatment with maslinic acid (MA), a NF-κB inhibitor, markedly attenuated the aberrant oncological behavior of PDAC cells caused by IRAK2 overexpression. CONCLUSIONS: Our data reveal a role of IRAK2 in PDAC metabolic reprogramming. In addition, we obtained novel insights into how immune-related pathways affect PDAC progression and suggest that targeting IRAK2 may serve as a novel therapeutic approach for PDAC.

SF3B1 mutation in pancreatic cancer contributes to aerobic glycolysis and tumor growth through a PP2A-c-Myc axis.

Hot spot gene mutations in splicing factor 3b subunit 1 (SF3B1) are observed in many types of cancer and create abundant aberrant mRNA splicing, which is profoundly implicated in tumorigenesis. Here, we identified that the SF3B1 K700E (SF3B1K700E ) mutation is strongly associated with tumor growth in pancreatic ductal adenocarcinoma (PDAC). Knockdown of SF3B1 significantly retarded cell proliferation and tumor growth in a cell line (Panc05.04) with the SF3B1K700E mutation. However, SF3B1 knockdown had no notable effect on cell proliferation in two cell lines (BxPC3 and AsPC1) carrying wild-type SF3B1. Ectopic expression of SF3B1K700E but not SF3B1WT in SF3B1-knockout Panc05.04 cells largely restored the inhibitory role induced by SF3B1 knockdown. Introduction of the SF3B1K700E mutation in BxPC3 and AsPC1 cells also boosted cell proliferation. Gene set enrichment analysis demonstrated a close correlation between SF3B1 mutation and aerobic glycolysis. Functional analyses showed that the SF3B1K700E mutation promoted tumor glycolysis, as evidenced by glucose consumption, lactate release, and extracellular acidification rate. Mechanistically, the SF3B1 mutation promoted the aberrant splicing of PPP2R5A and led to the activation of the glycolytic regulator c-Myc via post-translational regulation. Pharmacological activation of PP2A with FTY-720 markedly compromised the growth advantage induced by the SF3B1K700E mutation in vitro and in vivo. Taken together, our data suggest a novel function for SF3B1 mutation in the Warburg effect, and this finding may offer a potential therapeutic strategy against PDAC with the SF3B1K700E mutation.

CD74 promotes perineural invasion of cancer cells and mediates neuroplasticity via the AKT/EGR-1/GDNF axis in pancreatic ductal adenocarcinoma.

Perineural invasion (PNI) is a common feature of pancreatic ductal adenocarcinoma (PDAC) and is one of the important causes of local recurrence in resected pancreatic cancer, but the molecular mechanism remains largely unexplored. Here, we used immunohistochemistry staining to determine the expression of CD74. Then the in vivo PNI model, in vitro neuroplasticity assay, cell proliferation assay, wound healing and Transwell-based invasion assay were performed to examine the function of CD74 in pancreatic cancer cell lines. ChIP assay and Luciferase reporter assay were used to illustrate the mechanism underlying CD74 induced GDNF expression. We confirmed that the expression level of CD74 was an independent predictor of PNI and poor prognosis for PDAC. Moreover, we found that upregulation of CD74 on PDAC enhanced its migration and invasive capabilities and potentiated the secretion of neurotrophic factor GDNF to promote the neuroplasticity. Mechanistically, CD74 promoted GDNF production via the AKT/EGR-1/GDNF axis in PDAC. Taken together, our findings suggest a supportive role of CD74 in the PNI of PDAC, and deepen our understanding of how cancer cells promote neuroplasticity in the microenvironment of PDAC.

Single-cell RNA sequencing reveals that targeting HSP90 suppresses PDAC progression by restraining mitochondrial bioenergetics.

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers, which lacks effective treatment strategies. There is an urgent need for the development of new strategies for PDAC therapy. The genetic and phenotypic heterogeneity of PDAC cancer cell populations poses further challenges in the clinical management of PDAC. In this study, we performed single-cell RNA sequencing to characterize PDAC tumors from KPC mice. Functional studies and clinical analysis showed that PDAC cluster 2 cells with highly Hsp90 expression is much more aggressive than the other clusters. Genetic and pharmacologic inhibition of Hsp90 impaired tumor cell growth both in vitro and in vivo. Further mechanistic study revealed that HSP90 inhibition disrupted the interaction between HSP90 and OPA1, leading to a reduction in mitochondrial cristae amount and mitochondrial energy production. Collectively, our study reveals that HSP90 might be a potential therapeutic target for PDAC.

Perineural Invasion Reprograms the Immune Microenvironment through Cholinergic Signaling in Pancreatic Ductal Adenocarcinoma.

Perineural invasion is a common feature of pancreatic ductal adenocarcinoma (PDAC). Here, we investigated the effect of perineural invasion on the microenvironment and how this affects PDAC progression. Transcriptome expression profiles of PDAC tissues with different perineural invasion status were compared, and the intratumoral T-cell density and levels of neurotransmitters in these tissues were assessed. Perineural invasion was associated with impaired immune responses characterized by decreased CD8+ T and Th1 cells, and increased Th2 cells. Acetylcholine levels were elevated in severe perineural invasion. Acetylcholine impaired the ability of PDAC cells to recruit CD8+ T cells via HDAC1-mediated suppression of CCL5. Moreover, acetylcholine directly inhibited IFNγ production by CD8+ T cells in a dose-dependent manner and favored Th2 over Th1 differentiation. Furthermore, hyperactivation of cholinergic signaling enhanced tumor growth by suppressing the intratumoral T-cell response in an orthotopic PDAC model. Conversely, blocking perineural invasion with bilateral subdiaphragmatic vagotomy in tumor-bearing mice was associated with an increase in CD8+ T cells, an elevated Th1/Th2 ratio, and improved survival. In conclusion, perineural invasion-triggered cholinergic signaling favors tumor growth by promoting an immune-suppressive microenvironment characterized by impaired CD8+ T-cell infiltration and a reduced Th1/Th2 ratio. SIGNIFICANCE: These findings provide a promising therapeutic strategy to modulate the immunosuppressive microenvironment of pancreatic ductal adenocarcinoma with severe perineural invasion.

Clinical significance of programmed death 1/programmed death ligand 1 pathway in gastric neuroendocrine carcinomas.

BACKGROUND: Recently, more and more studies have demonstrated the pivotal role of programmed death 1/programmed death ligand 1 (PD-1/PD-L1) pathway in the immune evasion of tumors from the host immune system. However, the role of PD-1/PD-L1 pathway in gastric neuroendocrine carcinomas (G-NECs) remains unknown. AIM: To investigate the expression of PD-1/PD-L1 and role of PD-1/PD-L1 pathway in G-NECs, which occur rarely but are highly malignant and clinically defiant. METHODS: We investigated the expression of PD-L1 on tumor cells and PD-1+, CD8+, and FOXP3+ T cell infiltration by immunohistochemistry in 43 resected G-NEC tissue specimens. The copy number alterations of PD-L1 were assessed by qRT-PCR. RESULTS: Most of the G-NECs tumor cells exhibited a near-uniform expression pattern of PD-L1, while some showed a tumor-stromal interface enhanced pattern. Of the 43 G-NECs, 21 (48.8%) were classified as a high PD-L1 expression group, and the high expression of PD-L1 was associated with poor overall survival (OS). The high expression of PD-L1 was correlated with abundant PD-1+ tumor infiltrating lymphocytes (TILs) instead of CD8+ TILs and FOXP3+ regulatory T cells (Tregs). Our analysis also suggested that the infiltration of CD8+ TILs tended to be a favorable factor for OS, although the difference did not reach the statistical significance (P = 0.065). Meanwhile, PD-L1 was significantly overexpressed in cases with copy number gain as compared with those without. CONCLUSION: Our data demonstrated for the first time that high expression of PD-L1 in G-NECs is associated with a poor prognosis, while the high expression may be due to the copy number variation of PD-L1 gene or stimulation of TILs. These results provide a basis for the immunotherapy targeting PD-1/PD-L1 pathway in G-NECs.

SFRP4 is a prognostic marker and correlated with Treg cell infiltration in pancreatic ductal adenocarcinoma.

Secreted Frizzled-Related Protein 4 (SFRP4), a member of secreted frizzled-related protein family, has been found as a vital modulator in cell proliferation, cell self-renew and apoptosis through Wnt signaling transduction pathway. In the present study, we re-analyzed the expression pattern of SFRPs in Gene Expression Omnibus (GEO) datasets and evaluated the expression of SFRP4 at protein level in both KrasG12D/+; Trp53R172H/+; Pdx1-Cre; (KPC) mice and human pancreatic ductal adenocarcinoma (PDAC) tissue. We found that the expression of SFRP4 increased gradually in PanINs and PDAC lesions in KPC mice and high expression of SFRP4 was much more common in tumor lesions compared to the adjacent non-tumor tissues. Then we performed Kaplan-Meier survival and Cox regression analysis and found that high expression of SFRP4 in the serum and tumor lesions predicted poor prognosis for pancreatic cancer patients. Furthermore, we demonstrated that SFRP4 positively correlated with FOXP3+ Treg cells infiltration while the down-regulation of SFRP4 in tumor cells impaired the production of cytokines and the recruitments of T cells. This study suggested that SFRP4 can be a novel prognostic biomarker and potential therapeutic target for pancreatic cancer.

Targeting Purinergic Receptor P2Y2 Prevents the Growth of Pancreatic Ductal Adenocarcinoma by Inhibiting Cancer Cell Glycolysis.

PURPOSE: Extensive research has reported that the tumor microenvironment components play crucial roles in tumor progression. Thus, blocking the supports of tumor microenvironment is a promising approach to prevent cancer progression. We aimed to determine whether blocking extracellular ATP-P2RY2 axis could be a potential therapeutic approach for PDAC treatment. EXPERIMENTAL DESIGN: Expression of P2RY2 was determined in 264 human PDAC samples and correlated to patient survival. P2RY2 was inhibited in human PDAC cell lines by antagonist and shRNA, respectively, and cell viability, clonogenicity, and glycolysis were determined. RNA sequencing of PDAC cell line was applied to reveal underlying molecular mechanisms. Multiple PDAC mouse models were used to assess the effects of the P2RY2 inhibition on PDAC progression. RESULTS: P2RY2 was upregulated and associated with poor prognosis in PDAC. Activated P2RY2 by increased extracellular ATP in tumor microenvironment promoted PDAC growth and glycolysis. Further studies showed that the agonist-activated P2RY2 triggered PI3K/AKT-mTOR signaling by crosstalk with PDGFR mediated by Yes1, resulting in elevated expression of c-Myc and HIF1α, which subsequently enhanced cancer cell glycolysis. Genetic and pharmacologic inhibition of P2RY2 impaired tumor cell growth in subcutaneous and orthotopic xenograft model, as well as delayed tumor progression in inflammation-driven PDAC model. In addition, synergy was observed when AR-C118925XX, the selective antagonist of P2RY2 receptor, and gemcitabine were combined, resulting in prolonged survival of xenografted PDAC mice. CONCLUSIONS: These findings reveal the roles of the P2RY2 in PDAC metabolic reprogramming, suggesting that P2RY2 might be a potential metabolic therapeutic target for PDAC.

IL22RA1/STAT3 Signaling Promotes Stemness and Tumorigenicity in Pancreatic Cancer.

Chronic inflammation is a feature of pancreatic cancer, but little is known about how immune cells or immune cell-related signals affect pancreatic cancer stemness and development. Our previous work showed that IL22/IL22RA1 plays a vital role in acute and chronic pancreatitis progression by mediating cross-talk between immune cells and acinar cells or stellate cells, respectively. Here, we find IL22RA1 is highly but heterogeneously expressed in pancreatic cancer cells, with high expression associated with poor prognosis of patients with pancreatic cancer. The IL22RA1hi population from pancreatic cancer harbored higher stemness potential and tumorigenicity. Notably, IL22 promoted pancreatic cancer stemness via IL22RA1/STAT3 signaling, establishing the mechanism of regulation of cancer stemness by microenvironmental factors. Moreover, STAT3 was indispensable for the maintenance of IL22RA1hi cells. Overall, these findings provide a therapeutic strategy for patients with PDAC with high expression of IL22RA1.Significance: IL22RA1/STAT3 signaling enhances stemness and tumorigenicity in pancreatic cancer. Cancer Res; 78(12); 3293-305. ©2018 AACR.

High Expression of FAM83B Predicts Poor Prognosis in Patients with Pancreatic Ductal Adenocarcinoma and Correlates with Cell Cycle and Cell Proliferation.

FAM83B (family with sequence similarity 83, member B) seems to emerge as a new class of players involved in the development of a variety of malignant tumors. Yet the molecular mechanisms are not well understood. The present study is intended to investigate the expression and function of FAM83B in pancreatic ductal adenocarcinoma (PDAC). In this study, we found that the expression of FAM83B was significantly increased both in PDAC cell lines and PDAC tumor tissues. FAM83B expression was positively related with advanced clinical stage and poor vital status. Higher FAM83B expression predicted shorter overall survival in PDAC patients, regardless of lymphatic metastasis status and histological differentiation. Actually, FAM83B may act as an independent prognostic indicator as well. What's more, down-regulation of FAM83B in PDAC cells contributed to G0/G1 phase arrest and inhibition of cell proliferation. Finally, a subcutaneous xenograft model indicated that knockdown of FAM83B significantly reduced the tumor volume in vivo. Our findings have provided supporting evidence for the potential molecular biomarker role of FAM83B in PDAC. It's of great interest and broad significance to target FAM83B in PDAC, which may conduce to develop a meaningful and effective strategy in the diagnosis and treatment of PDAC.

The role of Dickkopf-1 as a potential prognostic marker in pancreatic ductal adenocarcinoma.

Dickkopf-1(DKK-1), the downstream target of ß-catenin/T-cell factor, participates in a negative feedback loop in the Wnt signaling and reported as an important biomarker in many tumors. In this study, we analyzed the expression of DKK-1 in pancreatic ductal adenocarcinoma (PDAC) patients at both mRNA and protein levels. We used real-time PCR to detect the expression of DKK-1 in 32 PDAC and paired adjacent non-tumor tissues, results suggested that the expression of DKK-1 was increased in PDAC tissues. We found the similar results in the analysis of 3 independent microarray data sets. Immunohistochemical staining of 311 pairs of PDAC tissues suggested that DKK-1 expression was significantly associated with T classification (P = 0.039) and lymph node metastasis (P = 0.035). Furthermore, Kaplan-Meier analysis for DKK-1 expression demonstrated that patients with higher DKK-1 level had shorter overall survival (OS) and relapse-free survival (RFS) time in Ren Ji cohort and online PDAC database at both mRNA and protein levels. Univariable and multivariable Cox regression analysis confirmed that DKK-1 as well as lymph node metastasis and histology were independent predictors of OS in patients with PDAC. This study demonstrated that DKK-1 may be a predictor for prognosis in PDAC patients.

Increased Serotonin Signaling Contributes to the Warburg Effect in Pancreatic Tumor Cells Under Metabolic Stress and Promotes Growth of Pancreatic Tumors in Mice.

BACKGROUND & AIMS: Desmoplasia and poor vascularity cause severe metabolic stress in pancreatic ductal adenocarcinomas (PDACs). Serotonin (5-HT) is a neuromodulator with neurotransmitter and neuroendocrine functions that contributes to tumorigenesis. We investigated the role of 5-HT signaling in the growth of pancreatic tumors. METHODS: We measured the levels of proteins that regulate 5-HT synthesis, packaging, and degradation in pancreata from KrasG12D/+/Trp53R172H/+/Pdx1-Cre (KPC) mice, which develop pancreatic tumors, as well as in PDAC cell lines and a tissue microarray containing 81 human PDAC samples. We also analyzed expression levels of proteins involved in 5-HT synthesis and degradation by immunohistochemical analysis of a tissue microarray containing 311 PDAC specimens, and associated expression levels with patient survival times. 5-HT level in 14 matched PDAC tumor and non-tumor tissues were analyzed by ELISA. PDAC cell lines were incubated with 5-HT and cell survival and apoptosis were measured. We analyzed expression of the 5-HT receptor HTR2B in PDAC cells and effects of receptor agonists and antagonists, as well as HTR2B knockdown with small hairpin RNAs. We determined the effects of 5-HT stimulation on gene expression profiles of BxPC-3 cells. Regulation of glycolysis by 5-HT signaling via HTR2B was assessed by immunofluorescence and immunoprecipitation analyses, as well as by determination of the extracellular acid ratio, glucose consumption, and lactate production. Primary PDACs, with or without exposure to SB204741 (a selective antagonist of HTR2B), were grown as xenograft tumors in mice, and SB204741 was administered to tumor-bearing KPC mice; tumor growth and metabolism were measured by imaging analyses. RESULTS: In immunohistochemical analysis of a tissue microarray of PDAC specimens, increased levels of TPH1 and decreased level of MAOA, which regulate 5-HT synthesis and degradation, correlated with stage and size of PDACs and shorter patient survival time. We found levels of 5-HT to be increased in human PDAC tissues compared with non-tumor pancreatic tissues, and PDAC cell lines compared with non-transformed pancreatic cells. Incubation of PDAC cell lines with 5-HT increased proliferation and prevented apoptosis. Agonists of HTR2B, but not other 5-HT receptors, promoted proliferation and prevented apoptosis of PDAC cells. Knockdown of HTR2B in PDAC cells, or incubation of cells with HTR2B inhibitors, reduced their growth as xenograft tumors in mice. We observed a correlation between 5-HT and glycolytic flux in PDAC cells; levels of metabolic enzymes involved in glycolysis, the phosphate pentose pathway, and hexosamine biosynthesis pathway increased significantly in PDAC cells following 5-HT stimulation. 5-HT stimulation led to formation of the HTR2B-LYN-p85 complex, which increased PI3K-Akt-mTOR signaling and the Warburg effect by increasing protein levels of MYC and HIF1A. Administration of SB204741 to KPC mice slowed growth and metabolism of established pancreatic tumors and prolonged survival of the mice. CONCLUSIONS: Human PDACs have increased levels of 5-HT, and PDAC cells increase expression of its receptor, HTR2B. These increases allow for tumor glycolysis under metabolic stress and promote growth of pancreatic tumors and PDAC xenograft tumors in mice.

Clinicopathological, treatment, and prognosis study of 43 gastric neuroendocrine carcinomas.

AIM: To provide more information and therapeutic methods about gastric neuroendocrine carcinomas (G-NECs) which occur rarely but are highly malignant and clinically challenging. METHODS: We retrospectively analyzed the clinicopathological characteristics, treatments, and prognosis of 43 G-NEC patients at our hospital between January 2007 and December 2014. The diagnosis was based on the 2010 World Health Organization criteria. RESULTS: Forty-three G-NECs containing 39 small cell carcinomas and 4 large cell NECs with Ki67 > 60% were included in this study, accounting for only 0.95% of all gastric carcinomas. The median patient age was 62 years (range, 33-82) and the male-to-female ratio was 4.4:1. All patients underwent surgery, including 38 curative resections and 5 palliative resections. Among these 43 patients, nearly half (48.84%) of these tumors were located in the cardiac region of the stomach, regional lymph node metastasis was found in 31 cases (72.09%), and liver metastasis was found in 6 cases (13.95%). Follow-up information was got for 40 patients. Twenty-three die of this disease with a median survival of 31 mo (range 1-90). The 1-year, 2-year, 3-year, and 5-year survival rate was 77.50%, 57.04%, 44.51%, and 35.05%, respectively. Survival was better in patients with tumor located in the cardiac region of the stomach, less than 7 lymph nodes metastasis and no liver metastasis. Five patients did not undergo postoperative chemotherapy, and the median survival time for these patients was 15 mo. For the remaining 34 patients who received postoperative chemotherapy, the median survival time was 44 mo and those received etoposide, cisplatin, and Paclitaxel survived the best. One patient with resected liver metastasis who received postoperative Capecitabine plus Oxaliplatin and Paclitaxel systemic chemotherapy plus octreotide LAR (30 mg intramuscularly, every 4 wk, for 2 years) has survived for 74 mo with no recurrence. CONCLUSION: G-NECs are mostly nonfunctioning, which lead to a delay in detection. Local and/or distant metastases were noticed in most patients when diagnosed, and they required postoperative medical treatment. Adjuvant etoposide, cisplatin plus Paclitaxel systemic chemotherapy is recommended for these patients.

Elevated expression of CTHRC1 predicts unfavorable prognosis in patients with pancreatic ductal adenocarcinoma.

Collagen triple helix repeat containing-1 (CTHRC1), a secreted protein, has been demonstrated as an oncogene in many types of human cancers including pancreatic ductal adenocarcinoma (PDAC). However, little is known about the prognostic value of CTHRC1 in PDAC. In current study, we investigated the expression pattern and underlying clinical significance of CTHRC1 in PDAC. Data from public PDAC microarray datasets, real-time PCR and immunohistochemistry demonstrated that CTHRC1 expression was dramatically increased in PDAC compared with normal tissues at both mRNA and protein level, which was consistent with previous studies. Analysis of its correlation with clinicopathological parameters indicated that high protein expression level of CTHRC1 was significantly associated with lymph node metastasis, vascular invasion and perineural invasion. Kaplan-Meier survival analysis showed that patients with higher CTHRC1 expression exhibited a remarkably shorter overall survival in four different PDAC patient cohorts. Importantly, univariable and multivariable Cox regression analysis revealed that CTHRC1 protein expression level was a significant and independent prognostic factor for overall survival rate of PDAC patients. Together, these data suggested that CTHRC1 is an unfavorable biomarker of prognosis in PDAC and may serve as a potential therapeutic candidate for PDAC treatment.

Analysis of long non-coding RNA expression profiles in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most aggressive and lethal malignancies. Long non-coding RNAs (lncRNAs) are a novel class of non-protein-coding transcripts that have been implicated in cancer biogenesis and prognosis. By repurposing microarray probes, we herein analysed the lncRNA expression profiles in two public PDAC microarray datasets and identified 34 dysregulated lncRNAs in PDAC. In addition, the expression of 6 selected lncRNAs was confirmed in Ren Ji cohort and pancreatic cell lines, and their association with 80 PDAC patients' clinicopathological features and prognosis was investigated. Results indicated that AFAP1-AS1, UCA1 and ENSG00000218510 might be involved in PDAC progression and significantly associated with overall survival of PDAC. UCA1 and ENSG00000218510 expression status may serve as independent prognostic biomarkers for overall survival of PDAC. Gene set enrichment analysis (GSEA) analysis suggested that high AFAP1-AS1, UCA1 and low ENSG00000218510 expression were correlated with several tumorigenesis related pathways. Functional experiments demonstrated that AFAP1-AS1 and UCA1 were required for efficient invasion and/or proliferation promotion in PDAC cell lines, while ENSG00000218510 acted the opposite. Our findings provide novel information on lncRNAs expression profiles which might be beneficial to the precise diagnosis, subcategorization and ultimately, the individualized therapy of PDAC.