Paracrine HGF/c-MET enhances the stem cell-like potential and glycolysis of pancreatic cancer cells via activation of YAP/HIF-1α.

Pancreatic stellate cells (PSCs), a pivotal component of the tumor microenvironment, contribute to tumor growth and metastasis. PSC-derived factors are essential for triggering the generation and maintenance of cancer stem cells (CSCs). However, the mechanisms by which paracrine signals regulate CSC-like properties such as glycolytic metabolism have not been fully elucidated. Here, we report that two pancreatic cancer cell lines, Panc-1 and MiaPaCa-2, reacted differently when treated with hepatocyte growth factor (HGF) secreted from PSCs. MiaPaCa-2 cells showed little response with regard to CSC-like properties after HGF treatment. We have shown that in Panc-1 cells by activating its cognate receptor c-MET, paracrine HGF resulted in YAP nuclear translocation and HIF-1α stabilization, thereby promoting the expression of CSC pluripotency markers NANOG, OCT-4 and SOX-2 and tumor sphere formation ability. Furthermore, HGF/c-MET/YAP/HIF-1α signaling enhanced the expression of Hexokinase 2 (HK2) and promoted glycolytic metabolism, which may facilitate CSC-like properties. Collectively, our study demonstrated that HGF/c-MET modulates tumor metabostemness by regulating YAP/HIF-1α and may hold promise as a potential therapeutic target against pancreatic cancer.

Targeting glypican-4 overcomes 5-FU resistance and attenuates stem cell-like properties via suppression of Wnt/ß-catenin pathway in pancreatic cancer cells.

The existences of cancer stem cells in patients with pancreatic cancer are considered as pivotal factors contributing to chemoresistance and disease relapse. Glypican-4 (GPC4) is one of the members of the glypicans family, which underlies human congenital malformations and multiple diseases. However, its potential biological function in pancreatic cancer still remains elusive. In this study, we are the first to demonstrate that GPC4 was involved in 5-fluorouracil (5-FU) resistance and pancreatic cancer stemness through comprehensive bioinformatical analysis. Functional experiments showed that knockdown of GPC4 sensitized pancreatic cancer cells to 5-FU and attenuated stem cell-like properties. In terms of mechanism research, knockdown of GPC4 suppressed the activation of Wnt/ß-catenin pathway and its downstream targets. Furthermore, the expression of GPC4 was significantly upregulated in pancreatic cancer tissues compared with normal tissues and remarkably correlated with patients' overall survival according to the data derived from the Cancer Genome Atlas database. Taken together, our results suggest that GPC4 is a key regulator in chemoresistance and pancreatic cancer stemness. Thus, targeting GPC4 may serve as a promising strategy for pancreatic cancer therapy.

Effects of developmental acclimation on fitness costs differ between two aphid species.

Most ectotherms are able to increase their tolerance to heat stress via the acclimation response. However, there is ongoing debate about whether the acclimation response is associated with fitness costs, and what factors can affect the consequences of acclimation are still unclear. To elucidate this, we sought to determine whether fitness costs varied with acclimation conditions in two cereal aphids, Sitobion avenae and Rhopalosiphum padi. Thus, the basal and inducible thermal tolerances (maximum critical temperature [CTmax]) and fitness traits (proportion of adult emergence, adult longevity, fecundity, and population parameters) of adult aphids were measured under three conditions of developmental acclimation: 1) 22 °C constant temperature (no acclimation), 2) 22 °C + 34 °C for 2 h per day (low daytime temperature), and 3) 22 °C + 38 °C for 2 h per day (high daytime temperature). We found that the thermal tolerances of both species were significantly higher following developmental acclimations, where higher basal and inducible thermal tolerances were observed in R. padi than in S. avenae. Low daytime temperature acclimation conditions (34 °C) resulted in negligible reproductive costs and improved the intrinsic rates of population increase in both species. In contrast, substantial fitness costs were detected in both species in response to high daytime temperature acclimation (38 °C), especially for S. avenae. Our results indicate that the effects of acclimation conditions on fitness costs differ between the two aphid species. These findings will not only enhance our understanding of species dynamics in the context of climate change but could also potentially improve pest control efforts.

Metformin suppresses cancer initiation and progression in genetic mouse models of pancreatic cancer.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-associated mortality worldwide with an overall five-year survival rate less than 7%. Accumulating evidence has revealed the cancer preventive and therapeutic effects of metformin, one of the most widely prescribed medications for type 2 diabetes mellitus. However, its role in pancreatic cancer is not fully elucidated. Herein, we aimed to further study the preventive and therapeutic effects of metformin in genetically engineered mouse models of pancreatic cancer. METHODS: LSL-KrasG12D/+; Pdx1-Cre (KC) mouse model was established to investigate the effect of metformin in pancreatic tumorigenesis suppression; LSL-KrasG12D/+; Trp53fl/+; Pdx1-Cre (KPC) mouse model was used to evaluate the therapeutic efficiency of metformin in PDAC. Chronic pancreatitis was induced in KC mice by peritoneal injection of cerulein. RESULTS: Following metformin treatment, pancreatic acinar-to-ductal metaplasia (ADM) and mouse pancreatic intraepithelial neoplasia (mPanIN) were decreased in KC mice. Chronic pancreatitis induced a stroma-rich and duct-like structure and increased the formation of ADM and mPanIN lesions, in line with an increased cytokeratin 19 (CK19)-stained area. Metformin treatment diminished chronic pancreatitis-mediated ADM and mPanIN formation. In addition, it alleviated the percent area of Masson's trichrome staining, and decreased the number of Ki67-positive cells. In KPC mice, metformin inhibited tumor growth and the incidence of abdominal invasion. More importantly, it prolonged the overall survival. CONCLUSIONS: Metformin inhibited pancreatic cancer initiation, suppressed chronic pancreatitis-induced tumorigenesis, and showed promising therapeutic effect in PDAC.

Photoelectrochemical properties of nanomultiple CaFe2O4/ZnFe2O4 pn junction photoelectrodes.

Nanomultiple CaFe2O4/ZnFe2O4pn junctions are prepared by a pulsed laser deposition method to explore their photoelectrochemical properties as the photoelectrodes. It is demonstrated that the multiple-pn-junction structure is favorable to enhancing the photocurrent density and the onset potential of the photoelectrode. Furthermore, the 20-junction photoelectrode-based PEC cell yields a high open circuit photovoltage of up to 0.97 V, which is much higher than that for a single pn junction photoelectrode PEC cell that yields an open circuit photovoltage of 0.13 V. A multiple-junction band structure model is assumed to describe the behavior of the CaFe2O4/ZnFe2O4 multiple-junction photoelectrodes. It is suggested that the open circuit photovoltage is dominated by the number of pn junctions in a multiple-junction photoelectrode and the carrier transfer inside the photoelectrode is improved by narrowing the single-layer thickness. These findings provide a new approach to designing the multiple-junction structure to improve the PEC properties of the photoelectrodes.

Surface-alkalinization-induced enhancement of photocatalytic H2 evolution over SrTiO3-based photocatalysts.

A strategy of reaction-environment modulation was employed to change the surface property of a semiconductor photocatalyst to enhance its photocatalytic performance. Surface alkalinization induced by a high alkalinity of the solution environment significantly shifted the surface energy band of a SrTiO(3) photocatalyst to a more negative level, supplying a strong potential for H(2)O reduction and consequently promoting the photocatalytic efficiency of H(2) evolution. This mechanism is also applicable for visible-light-sensitive La,Cr-codoped SrTiO(3) photocatalyst, which hence, could achieve a high apparent quantum efficiency of 25.6% for H(2) evolution in CH(3)OH aqueous solution containing 5 M NaOH at an incident wavelength of 425 ± 12 nm.

Facet effect of single-crystalline Ag3PO4 sub-microcrystals on photocatalytic properties.

We recently reported that Ag(3)PO(4) exhibits excellent photooxidative capabilities for O(2) evolution from water and organic dye decomposition under visible-light irradiation. However, very little is known about the shape and facet effects of Ag(3)PO(4) crystals on their photocatalytic properties. Herein we have developed a facile and general route for high-yield fabrication of single-crystalline Ag(3)PO(4) rhombic dodecahedrons with only {110} facets exposed and cubes bounded entirely by {100} facets. Moreover, studies of their photocatalytic performance have indicated that rhombic dodecahedrons exhibit much higher activities than cubes for the degradation of organic contaminants, which may be primarily ascribed to the higher surface energy of {110} facets (1.31 J/m(2)) than of {100} facets (1.12 J/m(2)).

An orthophosphate semiconductor with photooxidation properties under visible-light irradiation.

The search for active semiconductor photocatalysts that directly split water under visible-light irradiation remains one of the most challenging tasks for solar-energy utilization. Over the past 30 years, the search for such materials has focused mainly on metal-ion substitution as in In(1-x)Ni(x)TaO(4) and (V-,Fe- or Mn-)TiO(2) (refs 7,8), non-metal-ion substitution as in TiO(2-x)N(x) and Sm(2)Ti(2)O(5)S(2) (refs 9,10) or solid-solution fabrication as in (Ga(1-x)Zn(x))(N(1-x)O(x)) and ZnS-CuInS(2)-AgInS(2) (refs 11,12). Here we report a new use of Ag(3)PO(4) semiconductor, which can harness visible light to oxidize water as well as decompose organic contaminants in aqueous solution. This suggests its potential as a photofunctional material for both water splitting and waste-water cleaning. More generally, it suggests the incorporation of p block elements and alkali or alkaline earth ions into a simple oxide of narrow bandgap as a strategy to design new photoelectrodes or photocatalysts.

Fe3O4/WO3 hierarchical core-shell structure: high-performance and recyclable visible-light photocatalysis.

A facile solvothermal epitaxial growth combined with a mild oxidation route has been developed for the fabrication of a magnetically recyclable Fe(3)O(4)/WO(3) core-shell visible-light photocatalyst. In this core-shell structured photocatalyst, visible-light-active WO(3) nanoplates (the shells) with high surface area are used as a medium to harvest absorbed photons and convert them to photogenerated charges, while conductive Fe(3)O(4) microspheres (the cores) are used as charge collectors to transport the photogenerated charges. This is a new role for magnetite. The Fe(3)O(4)/WO(3) core-shell structured photocatalysts possess large surface-exposure area, high visible-light-absorption efficiency, stable recyclability, and efficient charge-separation properties, the combination of which has rarely been reported in other visible-light-active photocatalysts. Photoelectrochemical investigations verify that the core-shell structured Fe(3)O(4)/WO(3) has a more effective photoconversion capability than pure WO(3) or Fe(3)O(4). At the same time, the visible-light photocatalytic ability of the Fe(3)O(4)/WO(3) photocatalyst has significantly enhanced activity in the photodegradation of organic-dye materials. The results presented herein provide new insights into core-shell materials as high-performance visible-light photocatalysts and their potential use in environmental protection.

Facile synthesis of rhombic dodecahedral AgX/Ag3PO4 (X = Cl, Br, I) heterocrystals with enhanced photocatalytic properties and stabilities.

Herein, we have developed a facile and general method for the high-yield fabrication of AgX/Ag(3)PO(4) (X = Cl, Br, I) core-shell heterostructures with an unusual rhombic dodecahedral morphology, which exhibit much higher photocatalytic activities, structural stabilities and photoelectric properties than pure Ag(3)PO(4) crystals in environment and energy applications.

Knockdown of circular RNA septin 9 inhibits the malignant progression of breast cancer by reducing the expression of solute carrier family 1 member 5 in a microRNA-149-5p-dependent manner.

Breast cancer (BC) is the most frequently diagnosed cancer in women. Increasing evidence suggests that circular RNA (circRNA) exerts critical functions in BC progression. However, the roles of circRNA septin 9 (circSEPT9) in BC development and the underneath mechanism remain largely unclear so far. In this work, the RNA levels of circSEPT9, microRNA-149-5p (miR-149-5p) and solute carrier family 1 member 5 (SLC1A5) were detected by quantitative real-time polymerase chain reaction. Western blot was performed to check protein expression. Glutamine uptake, cell proliferation and cell apoptosis were investigated by glutamine uptake, cell counting kit-8, cell colony formation, 5-Ethynyl-29-deoxyuridine, flow cytometry analysis or DNA content quantitation assay. The interactions of miR-149-5p with circSEPT9 and SLC1A5 were identified by a dual-luciferase reporter assay. Mouse model assay was carried out to analyze the effect of circSEPT9 on tumor formation in vivo. Results showed that circSEPT9 and SLC1A5 expression were significantly upregulated, while miR-149-5p was downregulated in BC tissues and cells as compared with paracancerous normal breast tissues and human normal breast cells. Knockdown of circSEPT9 or SLC1A5 inhibited glutamine uptake and cell proliferation, but induced cell apoptosis in BC cells. SLC1A5 overexpression relieved circSEPT9 silencing-induced repression of BC cell malignancy. In mechanism, circSEPT9 regulated SLC1A5 expression by sponging miR-149-5p. In support, circSEPT9 knockdown led to delayed tumor tumorigenesis in vivo. In summary, these results indicates that circSEPT9 may act an oncogenic role in BC malignant progression by regulating miR-149-5p/SLC1A5 pathway, providing a novel mechanism responsible for BC development.

Complex delayed and transgenerational effects driven by the interaction of heat and insecticide in the maternal generation of the wheat aphid, Sitobion avenae.

BACKGROUND: Experience of an earlier environment plays an important role in the induction of delayed and even intergenerational phenotypes of an organism. Evidence suggests that rapid adaptation to an environmental stressor can change the performance of organisms, and even enable them to deal with other stressors. The goal of this study was to determine the effects of adult imidacloprid exposure on life-history traits within and between generations of the cereal aphid, Sitobion avenae, under three developmental conditions: constant temperature, 22°C; a low-intensity thermal condition, 22 + 34°C for 2 h per day; and a high-intensity thermal condition, 22 + 38°C for 2 h per day. RESULTS: Early thermal experience not only changed the tolerance of S. avenae to the insecticide, imidacloprid, but also caused adults to incur fitness costs: the higher the heat intensity, the higher the costs. Negative transgenerational impacts of combined heat and insecticide stressors were limited to the developmental stage, whereas positive stimulation of heat intensity was observed during the adult stage. Overall, nymphal thermal experience exacerbated the detrimental effects of adult insecticidal exposure on the intrinsic rate of population increase in the maternal generation, but stimulated a net reproductive rate in the succeeding offspring generation. CONCLUSION: These findings underpin the importance of considering the experience of the early developmental environment, but also enhance our understanding of the transgenerational effects of combined thermal and insecticide stressors on the population fate of S. avenae. They also help to assess the efficacy of chemical control in a warming world. © 2021 Society of Chemical Industry.

Diagnostic Value of Serum lncRNA HOTAIR Combined with Galectin-3 in Benign and Papillary Thyroid Carcinoma.

PURPOSE: Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. LncRNA HOTAIR (HOx Transcript AntIsense RNA) and Galectin-3 are involved in PTC. This study explored the clinical effect of lncRNA HOTAIR/Galectin-3 on PTC patients. METHODS: Subjects were assigned into PTC (160 cases) and benign thyroid tumor groups (150 cases). Fasting peripheral venous blood was collected. LncRNA HOTAIR/Galectin-3 expressions in serum were detected. Subjects were assigned into HOTAIR/Glactin-3 high/low expression groups and their correlation with age, gender, BMI, tumor size, pathological stage, TSH, TPO-Ab, and TG-Ab in PTC was analyzed. Receiver operating characteristic (ROC) curve was conducted on diagnostic efficacy of HOTAIR or/and Galectin-3. The difference of area under the curve (AUC) was compared and analyzed. RESULTS: HOTAIR and Glactin-3 were higher in PTC group and correlated with tumor pathological stage. Higher HOTAIR/Glactin-3 expression indicated a more advanced TNM stage. LncRNA HOTAIR was positively correlated with TPO-Ab and TG-Ab. AUC of HOTAIR for PTC diagnosis was 0.895, with 96.00% specificity and 80.63% sensitivity. AUC of Glactin-3 for PTC diagnosis was 0.817, with 66.67% specificity and 78.75% sensitivity. AUC of HOTAIR combining with Glactin-3 for PTC diagnosis was 0.969 with 96.00% specificity and 87.50% sensitivity. AUC of lncRNA HOTAIR was higher than that of Glactin-3, while AUC of the combination was higher than that of lncRNA HOTAIR or Glactin-3. CONCLUSION: LncRNA HOTAIR and Glactin-3 were highly expressed in PTC. The combination detection of lncRNA HOTAIR/Glactin-3 had higher diagnostic efficiency on the differential diagnosis of benign thyroid tumor and PTC.

Unraveling why we sleep: Quantitative analysis reveals abrupt transition from neural reorganization to repair in early development.

Sleep serves disparate functions, most notably neural repair, metabolite clearance and circuit reorganization. Yet the relative importance remains hotly debated. Here, we create a novel mechanistic framework for understanding and predicting how sleep changes during ontogeny and across phylogeny. We use this theory to quantitatively distinguish between sleep used for neural reorganization versus repair. Our findings reveal an abrupt transition, between 2 and 3 years of age in humans. Specifically, our results show that differences in sleep across phylogeny and during late ontogeny (after 2 or 3 years in humans) are primarily due to sleep functioning for repair or clearance, while changes in sleep during early ontogeny (before 2 or 3 years) primarily support neural reorganization and learning. Moreover, our analysis shows that neuroplastic reorganization occurs primarily in REM sleep but not in NREM. This developmental transition suggests a complex interplay between developmental and evolutionary constraints on sleep.

Mouse-Derived Allografts: A Complementary Model to the KPC Mice on Researching Pancreatic Cancer In Vivo.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant cancers and has an extremely undesirable prognosis because little is known about the initiation and progression mechanisms of pancreatic cancer. The lack of an appropriate research model may have hindered this process. Using LSL-Kras G12D/+ ; Trp53 fl/+ ; Pdx1-Cre (KPC) mice and the tumor tissue fragment transplantation technique, we constructed the mouse-derived subcutaneous/orthotopic allograft tumor models (MDAs-ST/OT). H&E staining, Masson staining and immunohistochemical staining were adopted to describe the histopathology and biomarkers of the MDAs and the recruitment of immune cells. The intervention of gemcitabine was applied to measure the chemotherapeutic response of MDAs tumors. MDAs could mimic the pathological histology and the high proliferation characteristics of PDAC. Indeed, the fibrosis, epithelial-mesenchyme transition (EMT) and invasion/metastasis related markers of MDAs were similar to those observed in pancreatic cancer. Further, the recruitment of immune cells in PDAC was precisely simulated by MDAs. In addition, gemcitabine suppressed the tumor growth of MDAs-ST significantly. MDAs are an effective model for investigating the progression and treatment of pancreatic cancer.

Hypoxia-driven paracrine osteopontin/integrin αvß3 signaling promotes pancreatic cancer cell epithelial-mesenchymal transition and cancer stem cell-like properties by modulating forkhead box protein M1.

Pancreatic stellate cells (PSCs), a key component of the tumor microenvironment, contribute to tumor invasion, metastasis, and chemoresistance. Osteopontin (OPN), a phosphorylated glycoprotein, is overexpressed in pancreatic cancer. However, OPN expression in PSCs and its potential roles in tumor-stroma interactions remain unclear. The present study first showed that OPN is highly expressed and secreted in activated PSCs driven by hypoxia, and this process is in a ROS-dependent manner; in addition, OPN was shown to be involved in the PSC-induced epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC)-like properties of pancreatic cancer cells (PCCs). Mechanistically, OPN from activated PSCs interacts with the transmembrane receptor integrin αvß3 on PCCs to upregulate forkhead box protein M1 (FOXM1) expression and induce malignant phenotypes of PCCs. Moreover, the Akt and Erk pathways participate in OPN/integrin αvß3 axis-induced FOXM1 expression of PCCs. Our further analysis showed that OPN and FOXM1 are significantly upregulated in pancreatic cancer tissues and are associated with poor clinical outcome, indicating that OPN and FOXM1 might be considered as diagnostic and prognostic biomarkers for patients with pancreatic cancer. In conclusion, we show here for the first time that OPN promotes the EMT and CSC-like properties of PCCs by activating the integrin αvß3-Akt/Erk-FOXM1 cascade in a paracrine manner, suggesting that targeting the tumor microenvironment represents a promising therapeutic strategy in pancreatic cancer.

Resveratrol enhances the chemotherapeutic response and reverses the stemness induced by gemcitabine in pancreatic cancer cells via targeting SREBP1.

OBJECTIVES: Gemcitabine is a standard treatment for advanced pancreatic cancer patients but can cause chemoresistance during treatment. The chemoresistant cells have features of cancer stem cells (CSCs). Resveratrol has been reported to overcome the resistance induced by gemcitabine. However, the mechanism by which resveratrol enhances chemosensitivity remains elusive. Here, we explored the mechanism by which resveratrol enhanced chemosensitivity and the role of sterol regulatory element binding protein 1 (SREBP1) in gemcitabine-induced stemness. MATERIALS AND METHODS: The pancreatic cancer cell lines MiaPaCa-2 and Panc-1 were treated under different conditions. Methyl thiazolyl tetrazolium and colony formation assays were performed to evaluate effects on proliferation. Flow cytometry was conducted to detect apoptosis. Oil red O staining was performed to examine lipid synthesis. The sphere formation assay was applied to investigate the stemness of cancer cells. Immunohistochemistry was performed on tumour tissue obtained from treated KPC mice. RESULTS: Resveratrol enhanced the sensitivity of gemcitabine and inhibited lipid synthesis via SREBP1. Knockdown of SREBP1 limited the sphere formation ability and suppressed the expression of CSC markers. Furthermore, suppression of SREBP1 induced by resveratrol reversed the gemcitabine-induced stemness. These results were validated in a KPC mouse model. CONCLUSIONS: Our data provide evidence that resveratrol reverses the stemness induced by gemcitabine by targeting SREBP1 both in vitro and in vivo. Thus, resveratrol can be an effective chemotherapy sensitizer, and SREBP1 may be a rational therapeutic target.

Betulinic acid inhibits stemness and EMT of pancreatic cancer cells via activation of AMPK signaling.

Cancer stem cells (CSCs), which are found in various types of human cancer, including pancreatic cancer, possess elevated metastatic potential, lead to tumor recurrence and cause chemoradiotherapy resistance. Alterations in cellular bioenergetics through the regulation of 5' adenosine monophosphate­activated protein kinase (AMPK) signaling may be a prerequisite to stemness. Betulinic acid (BA) is a well­known bioactive compound with antiretroviral and anti­inflammatory potential, which has been reported to exert anticancer effects on various types of cancer, including pancreatic cancer. The present study aimed to investigate whether BA could inhibit pancreatic CSCs via regulation of AMPK signaling. The proliferation of pancreatic cancer cells was examined by MTT and colony formation assays. The migratory and invasive abilities of pancreatic cancer cells were assessed using wound­scratch and Transwell invasion assays. In addition, the expression levels of candidate genes were measured by reverse transcription­quantitative polymerase chain reaction and western blotting. The results revealed that BA inhibited the proliferation and tumorsphere formation of pancreatic cancer cells, suppressed epithelial­mesenchymal transition (EMT), migration and invasion, and reduced the expression of three pluripotency factors [SRY­box 2 (Sox2), octamer­binding protein 4 (Oct4) and Nanog]. Furthermore, immunohistochemical analysis confirmed that there was a significant inverse association between the expression levels of phosphorylated (P)­AMPK and Sox2 in pancreatic cancer, and it was revealed that BA may activate AMPK signaling. Notably, knockdown of AMPK reversed the suppressive effects of BA on EMT and stemness of pancreatic cancer cells. In addition, BA reversed the effects of gemcitabine on stemness and enhanced the sensitivity of pancreatic cancer cells to gemcitabine. Collectively, these results indicated that BA may effectively inhibit pluripotency factor expression (Sox2, Oct4 and Nanog), EMT and the stem­like phenotype of pancreatic cancer cells via activating AMPK signaling. Therefore, BA may be considered an attractive therapeutic candidate and an effective inhibitor of the stem­like phenotype in pancreatic cancer cells. Further investigation into the development of BA as an anticancer drug is warranted.

Overexpression of Gremlin 1 by sonic hedgehog signaling promotes pancreatic cancer progression.

Sonic hedgehog (SHH) signaling is an important promotor of desmoplasia, a critical feature in pancreatic cancer stromal reactions involving the activation of pancreatic stellate cells (PSCs). Gremlin 1 is widely overexpressed in cancer-associated stromal cells, including activated PSCs. In embryonic development, SHH is a potent regulator of Gremlin 1 through an interaction network. This subtle mechanism in the cancer microenvironment remains to be fully elucidated. The present study investigated the association between Gremlin 1 and SHH, and the effect of Gremlin 1 in pancreatic cancer. The expression of Gremlin 1 in different specimens was measured using immunohistochemistry. The correlations among clinicopathological features and levels of Gremlin 1 were evaluated. Primary human PSCs and pancreatic cancer cell lines were exposed to SHH, cyclopamine, GLI family zinc finger-1 (Gli-1) small interfering RNA (siRNA), and Gremlin 1 siRNA to examine their associations and effects using an MTT assay, reverse transcription-quantitative polymerase chain reaction analysis, western blot analysis, and migration or invasion assays. The results revealed the overexpression of Gremlin 1 in pancreatic cancer tissues, mainly in the stroma. The levels of Gremlin 1 were significantly correlated with survival rate and pT status. In addition, following activation of the PSCs, the expression levels of Gremlin 1 increased substantially. SHH acts as a potent promoter of the expression of Gremlin 1, and cyclopamine and Gli-1 siRNA modulated this effect. In a screen of pancreatic cancer cell lines, AsPC-1 and BxPC-3 cells expressed high levels of Gremlin 1, but only AsPC-1 cells exhibited a high expression level of SHH. The results of the indirect co-culture experiment suggested that paracrine SHH from the AsPC-1 cells induced the expression of Gremlin 1 in the PSCs. Furthermore, Gremlin 1 siRNA negatively regulated the proliferation and migration of PSCs, and the proliferation, invasion and epithelial-mesenchymal transition of AsPC-1 and BxPC-3 cells. Based on the data from the present study, it was concluded that an abnormal expression level of Gremlin 1 in pancreatic cancer was induced by SHH signaling, and that the overexpression of Gremlin 1 enabled pancreatic cancer progression.

Norepinephrine enhances cell viability and invasion, and inhibits apoptosis of pancreatic cancer cells in a Notch­1­dependent manner.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive types of cancer, which is associated with a poor prognosis due to complexities in prevention, early diagnosis and effective treatment. The lack of understanding regarding its induction and specific pro­cancer mechanisms may contribute to its poor prognosis. The Notch­1 pathway is widely considered to be a critical tumor­promoting factor in PDAC. Previous studies have indicated that chronic psychological stress may promote the development of PDAC partially via the main downstream stress hormone, norepinephrine (NE); however, to the best of our knowledge, the role of the Notch­1 pathway in this process has not been studied. Therefore, the present study aimed to explore this process. The expression levels of Notch­1 pathway­associated molecules were measured in response to NE using reverse transcription­quantitative polymerase chain reaction and western blotting. Alongside NE treatment, two Notch­1 pathway blockers, Notch­1­specific small interfering (si)RNA and DAPT (an inhibitor of the Notch­1 pathway), were used to explore the relationship between NE and the Notch­1 pathway in the development of pancreatic cell malignant biological behaviors, including cell viability, apoptosis and cell invasion. The results demonstrated that treatment with NE enhanced cell viability and invasion, and inhibited apoptosis of PDAC cells; however, these effects were suppressed following treatment with Notch­1­specific siRNA and DAPT. In conclusion, NE may enhance the malignant biological behaviors of PDAC via activating the Notch­1 pathway.