Inhibiting YAP expression suppresses pancreatic cancer progression by disrupting tumor-stromal interactions

Serum ITIH5 as a novel diagnostic biomarker in cholangiocarcinoma

Cholangiocarcinoma often remains undetected until advanced stages due to the lack of reliable diagnostic markers. Our goal was to identify a unique secretory protein for cholangiocarcinoma diagnosis and differentiation from other malignancies, benign hepatobiliary diseases, and chronic liver conditions. We conducted bulk RNA-seq analysis to identify genes specifically upregulated in cholangiocarcinoma but not in most other cancers, benign hepatobiliary diseases, and chronic liver diseases focusing on exocrine protein-encoding genes. Single-cell RNA sequencing examined subcellular distribution. Immunohistochemistry and enzyme-linked immunosorbent assays assessed tissue and serum expression. Diagnostic performance was evaluated via receiver-operating characteristic (ROC) analysis. Inter-alpha-trypsin inhibitor heavy chain family member five (ITIH5), a gene encoding an extracellular protein, is notably upregulated in cholangiocarcinoma. This elevation is not observed in most other cancer types, benign hepatobiliary diseases, or chronic liver disorders. It is specifically expressed by malignant cholangiocytes. ITIH5 expression in cholangiocarcinoma tissues exceeded that in nontumorous bile duct, hepatocellular carcinoma, and nontumorous hepatic tissues. Serum ITIH5 levels were elevated in cholangiocarcinoma compared with controls (hepatocellular carcinoma, benign diseases, chronic hepatitis B, and healthy individuals). ITIH5 yielded areas under the ROC curve (AUCs) from 0.839 to 0.851 distinguishing cholangiocarcinoma from controls. Combining ITIH5 with carbohydrate antigen 19-9 (CA19-9) enhanced CA19-9's diagnostic effectiveness. In conclusion, serum ITIH5 may serve as a novel noninvasive cholangiocarcinoma diagnostic marker.

The DDX6/KIFC1 signaling axis, as regulated by YY1, contributes to the malignant behavior of pancreatic cancer

Human DEAD/H box RNA helicase DDX6 acts as an oncogene in several different types of cancer, where it participates in RNA processing. Nevertheless, the role of DDX6 in pancreatic cancer (PC), together with the underlying mechanism, has yet to be fully elucidated. In the present study, compared with adjacent tissues, the level of DDX6 was abnormally increased in human PC tissues, and this increased level of expression was associated with poor prognosis. Furthermore, the role of DDX6 in PC was investigated by overexpressing or silencing the DDX6 in the PC cell lines, SW1990 and PaTu-8988t. A xenograft model was established by injecting nude mice with either DDX6-overexpressing or DDX6-silenced SW1990 cells. DDX6 overexpression promoted the proliferation and cell cycle transition, inhibited the cell apoptosis of PC cells, and accelerated tumor formation, whereas DDX6 knockdown elicited the opposite effects. DDX6 exerted positive effects on PC. RNA immunoprecipitation assay showed that DDX6 bound to kinesin family member C1 (KIFC1) mRNA, which was further confirmed by RNA pull-down assay. These results suggested that DDX6 positively regulated the expression of KIFC1. KIFC1 overexpression enhanced the proliferative capability of PC cells with DDX6 knockdown and inhibited their apoptosis. By contrast, DDX6 overexpression reversed the inhibitory effect of KIFC1 silencing on tumor proliferation. Subsequently, the transcription factor Yin Yang 1 (YY1) was shown to negatively regulate DDX6 at both the mRNA and protein levels. Dual-luciferase reporter assay verified that YY1 targeted the promoter of DDX6 and inhibited its transcription. High expression levels of YY1 decreased the proliferation of PC cells and promoted cell apoptosis, although these effects were reversed by DDX6 overexpression. Taken together, YY1 may target the DDX6/KIFC1 axis, thereby negatively regulating its expression, leading to an inhibitory effect on pancreatic tumor.

An integrative pan-cancer analysis of WWC family genes and functional validation in lung cancer

The WW and C2 domain containing (WWC) protein family functions as scaffolds regulating cell proliferation and organ growth control through the Hippo signaling pathway. However, their pan-cancer dysregulation and mechanistic roles in signaling transduction have remained unclear. We performed integrated pan-cancer analyses of WWC family gene expression using data from The Cancer Genome Atlas (TCGA) across 33 different cancer types. Prognostic relevance was evaluated by survival analyses. WWC genetic alterations, DNA methylation, pathway activities, drug response, and tumor immunology were analyzed using online databases. Furthermore, we examined the functional roles of WWCs in lung cancer cells. We observed aberrant WWC expression in various cancers, which associated with patient prognosis. WWC hypermethylation occurred in many cancers and exhibited negative correlation with expression, alongside mutations linked to poor outcomes. Pathway analysis implicated WWCs as Hippo pathway scaffolds, while drug sensitivity analysis suggested associations with diverse chemotherapies. Additionally, pan-cancer analyses elucidated vital immunomodulatory roles for WWC through heterogeneous correlations with immune cell infiltrates, checkpoint molecules, tumor mutation burden, microsatellite instability, and chemokine pathways across cancers. Experimentally, WWCs suppressed lung cancer cell proliferation, migration, and invasion while enhancing apoptosis and paclitaxel chemosensitivity. Mechanistically, WWCs bound large tumor suppressor 1 and 2 (LATS1/2) kinases to stimulate phosphorylation cascades, thereby inhibiting nuclear translocation of the Yes-associated protein (YAP) oncoprotein. Taken together, our multi-omics characterization provides comprehensive evidence for WWCs as putative tumor suppressors across cancers via Hippo pathway modulation. WWCs may serve as prognostic markers and therapeutic targets in lung cancer.

The extracellular matrix as hallmark of cancer and metastasis: From biomechanics to therapeutic targets

The extracellular matrix (ECM) is essential for cell support during homeostasis and plays a critical role in cancer. Although research often concentrates on the tumor's cellular aspect, attention is growing for the importance of the cancer-associated ECM. Biochemical and physical ECM signals affect tumor formation, invasion, metastasis, and therapy resistance. Examining the tumor microenvironment uncovers intricate ECM dysregulation and interactions with cancer and stromal cells. Anticancer therapies targeting ECM sensors and remodelers, including integrins and matrix metalloproteinases, and ECM-remodeling cells, have seen limited success. This review explores the ECM's role in cancer and discusses potential therapeutic strategies for cell-ECM interactions.

Mind the (guidance) signals! Translational relevance of semaphorins, plexins, and neuropilins in pancreatic cancer

Pancreatic cancer is a major cause of demise worldwide. Although key associated genetic changes have been discovered, disease progression is sustained by pathogenic mechanisms that are poorly understood at the molecular level. In particular, the tissue microenvironment of pancreatic adenocarcinoma (PDAC) is usually characterized by high stromal content, scarce recruitment of immune cells, and the presence of neuronal fibers. Semaphorins and their receptors, plexins and neuropilins, comprise a wide family of regulatory signals that control neurons, endothelial and immune cells, embryo development, and normal tissue homeostasis, as well as the microenvironment of human tumors. We focus on the role of these molecular signals in pancreatic cancer progression, as revealed by experimental research and clinical studies, including novel approaches for cancer treatment.

Syndecan-2 modulates the YAP pathway in epithelial-to-mesenchymal transition-related migration, invasion, and drug resistance in colorectal cancer

Epithelial-to-mesenchymal transition (EMT) is associated with an invasive phenotype in colorectal cancer (CRC). Here, we examined the roles of YES-associated protein (YAP) and syndecan-2 (SDC2) in EMT-related progression, invasion, metastasis, and drug resistance in CRC. The expression levels of YAP and SDC2 in CRC patient tumor tissue were quantified by PCR and western blotting. EMT-associated characteristics were assessed using Transwell assays and immunohistochemistry. Co-immunoprecipitation, glutathione S-transferase pull-down, and luciferase reporter assays were used to assess interactions between YAP and SDC2. YAP was found to be highly expressed in tumor tissue from 13/16 CRC patients, while SDC2 was highly expressed in the tumor tissue of 12/16 CRC patients. Overexpression of YAP in colon cancer cells led to increased cell viability, invasion, migration, and oxaliplatin resistance demonstrating that YAP plays a role in EMT. In addition, overexpression of YAP led to decreased expression of the large tumor suppressor kinase 1 (LATS1) and mammalian sterile 20-like kinases (MST1/2). Decreased LATS1 expression was associated with increased levels of cell proliferation. Knockdown of YAP by shRNA interference led to decreased cell invasion, migration, and drug resistance in colon cancer cells and reduced tumorigenesis in a mouse xenograft model. Finally, we established that YAP interacted with SDC2, and demonstrated that SDC2 mediated the YAP pathway through the EMT-related factors BMP4, CTGF and FOXM1.

MicroRNAs as the pivotal regulators of cisplatin resistance in osteosarcoma

Osteosarcoma (OS) is an aggressive bone tumor that originates from mesenchymal cells. It is considered as the eighth most frequent childhood cancer that mainly affects the tibia and femur among the teenagers and young adults. OS can be usually diagnosed by a combination of MRI and surgical biopsy. The intra-arterial cisplatin (CDDP) and Adriamycin is one of the methods of choices for the OS treatment. CDDP induces tumor cell death by disturbing the DNA replication. Although, CDDP has a critical role in improving the clinical complication in OS patients, a high ratio of CDDP resistance is observed among these patients. Prolonged CDDP administrations have also serious side effects in normal tissues and organs. Therefore, the molecular mechanisms of CDDP resistance should be clarified to define the novel therapeutic modalities in OS. Multidrug resistance (MDR) can be caused by various cellular and molecular processes such as drug efflux, detoxification, and signaling pathways. MicroRNAs (miRNAs) are the key regulators of CDDP response by the post transcriptional regulation of target genes involved in MDR. In the present review we have discussed all of the miRNAs associated with CDDP response in OS cells. It was observed that the majority of reported miRNAs increased CDDP sensitivity in OS cells through the regulation of signaling pathways, apoptosis, transporters, and autophagy. This review highlights the miRNAs as reliable non-invasive markers for the prediction of CDDP response in OS patients.

PLVAP protein expression correlated with microbial composition, clinicopathological features, and prognosis of patients with stomach adenocarcinoma

PURPOSE

Plasmalemma vesicle-associated protein (PLVAP) is involved in many immune‑related signals; however, its role in stomach adenocarcinoma (STAD) remains to be elucidated. This study investigated PLVAP expression in tumor tissues and defined the value in STAD patients.

METHODS

A total of 96 patient paraffin-embedded STAD specimens and 30 paraffin-embedded adjacent non-tumor specimens from the Ninth Hospital of Xi'an were consecutively recruited in analyses. All RNA‑sequence data were available from the Cancer Genome Atlas database (TCGA). PLVAP protein expression was detected using immunohistochemistry. Microbial community analysis was performed by 16S rRNA gene sequencing using Illumina MiSeq. PLVAP mRNA expression was explored with the Tumor Immune Estimation Resource (TIMER), GEPIA, and UALCAN databases. The effect of PLVAP mRNA on prognosis was analyzed via GEPIA, and Kaplan-Meier plotter database. GeneMANIA and STRING databases were used to predict gene/protein interactions and functions. The relationships between PLVAP mRNA expression and tumor-infiltrated immune cells were analyzed via the TIMER and GEPIA databases.

RESULTS

Significantly elevated transcriptional and proteomic PLVAP expressions were found in STAD samples. Increased PLVAP protein and mRNA expression were significantly associated with advanced clinicopathological parameters and correlated with shorter disease-free survival (DFS) and overall survival (OS) in TCGA (P < 0.001). The microbiota in the PLVAP-rich (3+) group was significantly different from that in the PLVAP-poor (1+) group (P < 0.05). The results from TIMER showed that high PLVAP mRNA expression had significant positive correlations with CD4 + T cell (r = 0.42, P < 0.001).

CONCLUSION

PLVAP is a potential biomarker to predict the prognosis of patients with STAD, and the high level of PLVAP protein expression was closely related to bacteria. The relative abundance of Fusobacteriia was positvely associated with the level of PLVAP. In conclusion, positive staining for PLVAP was useful for predicting the poor prognosis of STAD with Fusobacteriia infection.

LXA4 inhibits TGF-β1-induced airway smooth muscle cells proliferation and migration by suppressing the Smad/YAP pathway

The aims of the present study were to examine the signaling mechanisms for transforming growth factor-β1 (TGF-β1)-induced rat airway smooth muscle cells (ASMCs) proliferation and migration and to determine the effect of lipoxin A4 (LXA4) on TGF-β1-induced rat ASMCs proliferation and migration and its underlying mechanisms. TGF-β1 upregulated transcriptional coactivator Yes-associated protein (YAP) expression by activating Smad2/3 and then upregulated cyclin D1, leading to rat ASMCs proliferation and migration. This effect was reversed after treatment with the TGF-β1 receptor inhibitor SB431542. YAP is a critical mediator of TGF-β1-induced ASMCs proliferation and migration. Knockdown of YAP disrupted the pro-airway remodeling function of TGF-β1. Preincubation of rat ASMCs with LXA4 blocked TGF-β1-induced activation of Smad2/3 and changed its downstream targets, YAP and cyclin D1, resulting in the inhibition of rat ASMCs proliferation and migration. Our study suggests that LXA4 suppresses Smad/YAP signaling to inhibit rat ASMCs proliferation and migration and therefore has potential value in the prevention and treatment of asthma by negatively modulating airway remodeling.

Epithelial and stromal co-evolution and complicity in pancreatic cancer

Pancreatic ductal adenocarcinomas are distinguished by their robust desmoplasia, or fibroinflammatory response. Dominated by non-malignant cells, the mutated epithelium must therefore combat, cooperate with or co-opt the surrounding cells and signalling processes in its microenvironment. It is proposed that an invasive pancreatic ductal adenocarcinoma represents the coordinated evolution of malignant and non-malignant cells and mechanisms that subvert and repurpose normal tissue composition, architecture and physiology to foster tumorigenesis. The complex kinetics and stepwise development of pancreatic cancer suggests that it is governed by a discrete set of organizing rules and principles, and repeated attempts to target specific components within the microenvironment reveal self-regulating mechanisms of resistance. The histopathological and genetic progression models of the transforming ductal epithelium must therefore be considered together with a programme of stromal progression to create a comprehensive picture of pancreatic cancer evolution. Understanding the underlying organizational logic of the tumour to anticipate and pre-empt the almost inevitable compensatory mechanisms will be essential to eradicate the disease.

YAP/TAZ as master regulators in cancer: modulation, function and therapeutic approaches

Our understanding of the function of the transcriptional regulators YAP and TAZ (YAP/TAZ) in cancer is advancing. In this Review, we provide an update on recent progress in YAP/TAZ biology, their regulation by Hippo signaling and mechanotransduction and highlight open questions. YAP/TAZ signaling is an addiction shared by multiple tumor types and their microenvironments, providing many malignant attributes. As such, it represents an important vulnerability that may offer a broad window of therapeutic efficacy, and here we give an overview of the current treatment strategies and pioneering clinical trials.

KRAS as a Key Oncogene in the Clinical Precision Diagnosis and Treatment of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant tumors, with a 5-year survival rate of less than 10%. At present, the comprehensive treatment based on surgery, radiotherapy and chemotherapy has encountered a bottleneck, and targeted immunotherapy turns to be the direction of future development. About 90% of PDAC patients have KRAS mutations, and KRAS has been widely used in the diagnosis, treatment, and prognosis of PDAC in recent years. With the development of liquid biopsy and gene testing, KRAS is expected to become a new biomarker to assist the stratification and prognosis of PDAC patients. An increasing number of small molecule inhibitors acting on the KRAS pathway are being developed and put into the clinic, providing more options for PDAC patients.

Recent insight into the role and therapeutic potential of YAP/TAZ in gastrointestinal cancers

With the rapid development of cancer treatment, gastrointestinal (GI) cancers are still the most prevalent malignancies with high morbidity and mortality worldwide. Dysregulation of the Hippo signaling pathway has been recognized to play a critical role during cancer development and adopted for monitoring disease progression and therapy response. Despite the well-documented tumor proliferation and metastasis, recent efforts in two core Hippo components, Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), have identified as the driving forces behind cancer metabolism, stemness, tumor immunity, and therapy resistance. Understanding the molecular mechanisms by which YAP/TAZ facilitates the tumorigenesis and progression of GI cancer, and identifying novel therapeutic strategies for targeting YAP/TAZ are crucial to GI cancer treatment and prevention. In this study, we summarize the latest findings on the function and regulatory mechanisms of YAP/TAZ in GI cancers, and highlight the translational significance of targeting YAP/TAZ for cancer therapies.

Effects of TP53 Mutations and miRs on Immune Responses in the Tumor Microenvironment Important in Pancreatic Cancer Progression

Approximately 90% of pancreatic cancers are pancreatic ductal adenocarcinomas (PDAC). PDAC is the fourth leading cause of cancer death world-wide. Therapies for PDAC are largely ineffective due to the dense desmoplastic tumor microenvironment which prevents chemotherapeutic drugs and small molecule inhibitors from exerting effective anti-cancer effects. In this review, we will discuss the roles of TP53 and miRs on the PDAC tumor microenvironment and how loss of the normal functions of TP53 promote tumor progression. The TP53 gene is mutated in approximately 50% of pancreatic cancers. Often, these TP53 mutations are point mutations which confer additional functions for the TP53 proteins. These are called gain of function (GOF) mutations (mut). Another class of TP53 mutations are deletions which result in loss of the TP53 protein; these are referred to TP53-null mutations. We have organized this review into various components/properties of the PDAC microenvironment and how they may be altered in the presence of mutant TP53 and loss of certain miR expression.

Harmine suppresses breast cancer cell migration and invasion by regulating TAZ-mediated epithelial-mesenchymal transition

Breast cancer is a highly lethal disease due to cancer metastasis. Harmine (HM), a β-carboline alkaloid, is present in various medicinal plants. Our previous study demonstrated that HM suppresses cell proliferation and migration by regulating TAZ in breast cancer cells and accelerates apoptosis. Epithelial-mesenchymal transition (EMT) plays an important role in the development of breast cancer by inducing the characteristics of cancer stem cells, cancer metastasis and recurrence. Overexpression of TAZ was shown to mediate EMT in breast cancer cells. We aimed to investigate whether HM inhibits EMT and metastasis of breast cancer cells by targeting TAZ. In this study, the cells treated with HM or with downregulated expression of TAZ showed an increase in epithelial markers and decrease in mesenchymal markers in breast cancer cells. Consistently, the breast cancer cells treated with HM or with downregulated expression of TAZ showed suppressed migration and proliferation. Moreover, TAZ overexpression reversed EMT and metastasis induced by HM in breast cancer cells. Thus, HM suppresses EMT and metastasis and invasion by targeting TAZ in breast cancer cells. HM can be used as an anticancer drug for breast cancer treatment and chemoprevention.

HNRNPC regulates RhoA to induce DNA damage repair and cancer-associated fibroblast activation causing radiation resistance in pancreatic cancer

Pancreatic cancer (PC) is one of the most lethal types of cancer due to its asymptomatic nature in the early stages and consequent late diagnosis. Its mortality rate remains high despite advances in treatment strategies, which include a combination of surgical resection and adjuvant therapy. Although these approaches may have a positive effect on prognosis, the development of chemo- and radioresistance still poses a significant challenge for successful PC treatment. Heterogeneous nuclear ribonucleoprotein C1/C2 (HNRNPC) and RhoA have been implicated in the regulation of tumour cell proliferation and chemo- and radioresistance. Our study aims to investigate the mechanism for HNRNPC regulation of PC radiation resistance via the RhoA pathway. We found that HNRNPC and RhoA mRNA and protein expression levels were significantly higher in PC tissues compared to adjacent non-tumour tissue. Furthermore, high HNRNPC expression was associated with poor patient prognosis. Using HNRNPC overexpression and siRNA interference, we demonstrated that HNRNPC overexpression promoted radiation resistance in PC cells, while HNRNPC knockdown increased radiosensitivity. However, silencing of RhoA expression was shown to attenuate radiation resistance caused by HNRNPC overexpression. Next, we identified RhoA as a downstream target of HNRNPC and showed that inhibition of the RhoA/ROCK2-YAP/TAZ pathway led to a reduction in DNA damage repair and radiation resistance. Finally, using both in vitro assays and an in vivo subcutaneous tumour xenograft model, we demonstrated that RhoA inhibition can hinder the activity of cancer-related fibroblasts and weaken PC radiation resistance. Our study describes a role for HNRNPC and the RhoA/ROCK2-YAP/TAZ signalling pathways in mediating radiation resistance and provides a potential therapeutic target for improving the treatment of PC.

Sequestration of Intestinal Acidic Toxins by Cationic Resin Attenuates Pancreatic Cancer Progression through Promoting Autophagic Flux for YAP Degradation

Simple Summary

Annually, more than 450,000 people are diagnosed with pancreatic cancer worldwide with over 430,000 mortalities. Pancreatic ductal carcinoma (PDAC) accounts for around 80% of pancreatic cancer cases with an extremely high mortality rate. Emerging research has demonstrated that gut dysbiosis is closely associated with pancreatic cancer, while the underlying mechanisms remain elusive. In this study, we found that elevated levels of endotoxin (LPS) and bile acids were associated with malignant progression in Kras-driven pancreatic cancer mice. Importantly, oral administration of cationic resins to sequestrate intestinal endotoxins and bile acids efficiently attenuated tumor progression. Thus, sequestration of intestinal acidic toxins by oral administration of cationic resins may have potential as an intervention strategy for pancreatic malignancy.

Abstract

Pancreatic cancer is driven by risk factors such as diabetes and chronic pancreatic injury, which are further associated with gut dysbiosis. Intestinal toxins such as bile acids and bacterial endotoxin (LPS), in excess and persistence, can provoke chronic inflammation and tumorigenesis. Of interest is that many intestinal toxins are negatively charged acidic components in essence, which prompted us to test whether oral administration of cationic resin can deplete intestinal toxins and ameliorate pancreatic cancer. Here, we found that increased plasma levels of endotoxin and bile acids in Pdx1-Cre: LSL-Kras^G12D/+ mice were associated with the transformation of the pancreatic ductal carcinoma (PDAC) state. Common bile-duct-ligation or LPS injection impeded autolysosomal flux, leading to Yap accumulation and malignant transformation. Conversely, oral administration of cholestyramine to sequestrate intestinal endotoxin and bile acids resumed autolysosomal flux for Yap degradation and attenuated metastatic incidence. Conversely, chloroquine treatment impaired autolysosomal flux and exacerbated malignance, showing jeopardization of p62/ Sqxtm1 turnover, leading to Yap accumulation, which is also consistent with overexpression of cystatin A (CSTA) in situ with pancreatic cancer cells and metastatic tumor. At cellular levels, chenodeoxycholic acid or LPS treatment activated the ligand–receptor-mediated AKT-mTOR pathway, resulting in autophagy-lysosomal stress for YAP accumulation and cellular dissemination. Thus, this work indicates a potential new strategy for intervention of pancreatic metastasis through sequestration of intestinal acidic toxins by oral administration of cationic resins.

Targeting Wnt/tenascin C-mediated cross talk between pancreatic cancer cells and stellate cells via activation of the metastasis suppressor NDRG1

A major barrier to successful pancreatic cancer (PC) treatment is the surrounding stroma, which secretes growth factors/cytokines that promote PC progression. Wnt and tenascin C (TnC) are key ligands secreted by stromal pancreatic stellate cells (PSCs) that then act on PC cells in a paracrine manner to activate the oncogenic β-catenin and YAP/TAZ signaling pathways. Therefore, therapies targeting oncogenic Wnt/TnC cross talk between PC cells and PSCs constitute a promising new therapeutic approach for PC treatment. The metastasis suppressor N-myc downstream-regulated gene-1 (NDRG1) inhibits tumor progression and metastasis in numerous cancers, including PC. We demonstrate herein that targeting NDRG1 using the clinically trialed anticancer agent di-2-pyridylketone-4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC) inhibited Wnt/TnC-mediated interactions between PC cells and the surrounding PSCs. Mechanistically, NDRG1 and DpC markedly inhibit secretion of Wnt3a and TnC by PSCs, while also attenuating Wnt/β-catenin and YAP/TAZ activation and downstream signaling in PC cells. This antioncogenic activity was mediated by direct inhibition of β-catenin and YAP/TAZ nuclear localization and by increasing the Wnt inhibitor, DKK1. Expression of NDRG1 also inhibited transforming growth factor (TGF)-β secretion by PC cells, a key mechanism by which PC cells activate PSCs. Using an in vivo orthotopic PC mouse model, we show DpC downregulated β-catenin, TnC, and YAP/TAZ, while potently increasing NDRG1 expression in PC tumors. We conclude that NDRG1 and DpC inhibit Wnt/TnC-mediated interactions between PC cells and PSCs. These results further illuminate the antioncogenic mechanism of NDRG1 and the potential of targeting this metastasis suppressor to overcome the oncogenic effects of the PC-PSC interaction.

A Novel Small Molecular Prostaglandin Receptor EP4 Antagonist, L001, Suppresses Pancreatic Cancer Metastasis

Metastatic pancreatic cancer remains a major clinical challenge, emphasizing the urgent need for the exploitation of novel therapeutic approaches with superior response. In this study, we demonstrate that the aberrant activation of prostaglandin E₂ (PGE₂) receptor 4 (EP4) is a pro-metastatic signal in pancreatic cancer. To explore the therapeutic role of EP4 signaling, we developed a potent and selective EP4 antagonist L001 with single-nanomolar activity using a panel of cell functional assays. EP4 antagonism by L001 effectively repressed PGE₂-elicited cell migration and the invasion of pancreatic cancer cells in a dose-dependent manner. Importantly, L001 alone or combined with the chemotherapy drug gemcitabine exhibited remarkably anti-metastasis activity in a pancreatic cancer hepatic metastasis model with excellent tolerability and safety. Mechanistically, EP4 blockade by L001 abrogated Yes-associated protein 1 (YAP)-driven pro-metastatic factor expression in pancreatic cancer cells. The suppression of YAP’s activity was also observed upon L001 treatment in vivo. Together, these findings support the notions that EP4–YAP signaling axis is a vital pro-metastatic pathway in pancreatic cancer and that EP4 inhibition with L001 may deliver a therapeutic benefit for patients with metastatic pancreatic cancer.

Nodal Enhances Perineural Invasion in Pancreatic Cancer by Promoting Tumor-Nerve Convergence

Perineural invasion (PNI) is a typical feature of pancreatic ductal adenocarcinoma (PDAC), which occurs in most cases. The embryonic protein Nodal plays a critical role in embryonic neural development and is overexpressed in human pancreatic cancer. In this study, we explored the contribution of Nodal to pancreatic cancer PNI and progression. We evaluated the function of Nodal in PNI by coculturing rat dorsal root ganglia and pancreatic cancer cells in vitro and performing cellular and molecular biology assays. The results illustrate that Nodal upregulates NGF (nerve growth factor), BDNF (brain-derived neurotrophic factor), and GDNF (glial cell line-derived neurotrophic factor) expression in pancreatic cancer cells and promotes cancer cell migration/invasion. Furthermore, in the in vitro 3D PNI model, Nodal enhances nerve outgrowth to pancreatic cancer cell colonies. Our study indicates that Nodal participates in tumor invasion by mediating neural and tumor cell signaling interactions, and inhibiting the expression of Nodal represents a potential strategy for targeting PNI in pancreatic cancer therapy.

Arl4c promotes the growth and drug resistance of pancreatic cancer by regulating tumor-stromal interactions

Emerging evidence suggests that ADP-ribosylation factor like-4c (Arl4c) may be a potential choice for cancer treatment. However, its role in pancreatic cancer, especially in tumor-stroma interactions and drug resistance, is still unknown. In the current study, we examined the proliferation and drug resistance effect of Arl4c on pancreatic cancer cells. Furthermore, we explored the contribution of Arl4c high expression in pancreatic stellate cell (PSC) activation. We found that high Arl4c expression is associated with cell proliferation, drug resistance, and PSC activation. In detail, Arl4c regulates connective tissue growth factor (CTGF) paracrine, further induces autophagic flux in PSCs, resulting in PSC activation. TGFβ1 secreted by activated PSCs enhances cancer cell stem cell properties via smad2 signaling, further increasing cell drug resistance. YAP is an important mediator of the Arl4c-CTGF loop. Taken together, these results suggest that Arl4c is essential for pancreatic cancer progression and may be an effective therapeutic choice.

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High Arl4c expression is correlated with PSCs activation and drug resistance

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Yap-CTGF-mediated autophagy is required for Arl4c-related PSCs activation

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Paracrine TGFβ1 of PSCs plays pivotal role in drug resistance of pancreatic cancer cells

Post-translational down-regulation of Nrf2 and YAP proteins, by targeting deubiquitinases, reduces growth and chemoresistance in pancreatic cancer cells

The intrinsic chemoresistance of pancreatic ductal adenocarcinoma (PDAC) represents the main obstacle in treating this aggressive malignancy. It has been observed that high antioxidant levels and upregulated Nrf2 and the YAP protein expression can be involved in PDAC chemoresistance. The mechanisms of Nrf2 and YAP increase need to be clarified. We chose a panel of PDAC cell lines with diverse sensitivity to cisplatin and gemcitabine. In PANC-1 chemoresistant cells, we found a low level of oxidative stress and high levels of Nrf2 and YAP protein expressions and their respective targets. On the contrary, in CFPAC-1 chemosensitive cells, we found high levels of oxidative stress and low level of these two proteins, as well as their respective targets. In MiaPaCa-2 cells with a middle chemoresistance, we observed intermediate features. When Nrf2 and YAP were inhibited in PANC-1 cells by Ailanthone, a plant extract, we observed a reduction of viability, thus sustaining the role of these two proteins in maintaining the PDAC chemoresistance. We then delved into the mechanisms of the Nrf2 and YAP protein upregulation in chemoresistance, discovering that it was at a post-translational level since the mRNA expressions did not match the protein levels. Treatments of PANC-1 cells with the proteasome inhibitor MG-132 and the protein synthesis inhibitor cycloheximide further confirmed this observation. The expression of DUB3 and OTUD1 deubiquitinases, involved in the control of Nrf2 and YAP protein level, respectively, was also investigated. Both protein expressions were higher in PANC-1 cells, intermediate in MiaPaCa-2 cells, and lower in CFPAC-1 cells. When DUB3 or OTUD1 were silenced, both Nrf2 and YAP expressions were downregulated. Importantly, in deubiquitinase-silenced cells, we observed a great reduction of proliferation and a higher sensitivity to gemcitabine treatment, suggesting that DUB3 and OTUD1 can represent a suitable target to overcome chemoresistance in PDAC cells.

Autophagy-mediated negative feedback attenuates the oncogenic activity of YAP in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal malignancy in humans, and new therapeutic targets are urgently needed. Yes-associated protein (YAP) plays a significant role in cancer progression. Autophagy is also closely associated with various human cancers. However, the interplay between YAP and autophagy in PDAC remains poorly understood. In this study, we found that YAP was upregulated and activated in PDAC. Further analysis revealed that there is a YAP-autophagy feedback loop in pancreatic cancer. Mechanistically, YAP activates autophagy by promoting Atg5 transcription via TEAD1-mediated binding, while autophagy negatively regulates YAP through autophagic degradation. The hyperactivation of YAP in PDAC unbalances the YAP-autophagy circuit and promotes cancer progression. Inhibition of autophagy enhances the oncogenic activity of YAP in PDAC. The autophagy activator rapamycin promotes the antitumor effect of verteporfin, a YAP inhibitor. Therefore, our study elucidated the interaction between YAP and autophagy in PDAC and our results suggest that targeting the YAP-autophagy circuit may be a new therapeutic strategy for pancreatic cancer.

NBPF4 mitigates progression in colorectal cancer through the regulation of EZH2-associated ETFA

Colorectal cancer (CRC) is one of the leading causes of death worldwide, and hence, there is a need to elucidate the molecular mechanisms contributing to the progression of CRC. In this study, we aimed at assessing the role of long non‐coding RNA NBPF4 on the tumorigenesis of CRC. Silencing or overexpression experiments were performed on HCT116 and SW260 in vitro models. BALB/c athymic female nude mice aged 5–6 weeks were used as in vivo models. To assess the relationship between NBPF4 and its regulatory RNA pull‐down assay, RNA immunoprecipitation, luciferase activity, Western blotting and qRT‐PCR were employed. Initially, we identified that NBPF4 was downregulated in CRC tissues and cell lines. Furthermore, we observed that NBPF4 decreased tumorigenesis in both in vitro and in vivo models. Additionally, we identified that ETFA was highly expressed in CRCs and was negatively associated with NBPF4. Subsequently, we identified that EZH2, a transcriptional factor, activated ETFA by enhancing the methylation of its promoter, and EZH2 was also highly regulated in CRCs. Using COAD and READ databases, we confirmed that EZH2 and ETFA were positively correlated. Furthermore, we identified NBPF4 and EZH2 were targets for ZFP36, which bound and positively regulated NBPF4. This prevented NBPF4 from binding to its negative regulator miR‐17‐3p. Our results demonstrated that NBPF4 downregulated EZH2 and stabilized itself by binding to ZFP36, thus escaping from inhibition by miR‐17‐3p, which allowed mitigation of CRC through inhibition of ETFA.

The molecular biology of pancreatic adenocarcinoma: translational challenges and clinical perspectives

Pancreatic cancer is an increasingly common cause of cancer mortality with a tight correspondence between disease mortality and incidence. Furthermore, it is usually diagnosed at an advanced stage with a very dismal prognosis. Due to the high heterogeneity, metabolic reprogramming, and dense stromal environment associated with pancreatic cancer, patients benefit little from current conventional therapy. Recent insight into the biology and genetics of pancreatic cancer has supported its molecular classification, thus expanding clinical therapeutic options. In this review, we summarize how the biological features of pancreatic cancer and its metabolic reprogramming as well as the tumor microenvironment regulate its development and progression. We further discuss potential biomarkers for pancreatic cancer diagnosis, prediction, and surveillance based on novel liquid biopsies. We also outline recent advances in defining pancreatic cancer subtypes and subtype-specific therapeutic responses and current preclinical therapeutic models. Finally, we discuss prospects and challenges in the clinical development of pancreatic cancer therapeutics.

Extracellular matrix stiffness controls VEGF165 secretion and neuroblastoma angiogenesis via the YAP/RUNX2/SRSF1 axis

Aberrant variations in angiogenesis have been observed in tumor tissues with abnormal stiffness of extracellular matrix (ECM). However, it remains largely unclear how ECM stiffness influences tumor angiogenesis. Numerous studies have reported that vascular endothelial growth factor-A (VEGF-A) released from tumor cells plays crucial roles in angiogenesis. Hence, we demonstrated the role of ECM stiffness in VEGF-A release from neuroblastoma (NB) cells and the underlying mechanisms. Based on 17 NB clinical samples, a negative correlation was observed between the length of blood vessels and stiffness of NB tissues. In vitro, an ECM stiffness of 30 kPa repressed the secretion of VEGF₁₆₅ from NB cells which subsequently inhibited the tube formation of human umbilical vein endothelial cells (HUVECs). Knocked down VEGF₁₆₅ in NB cells or blocked VEGF₁₆₅ with neutralizing antibodies both repressed the tube formation of HUVECs. Specifically, 30 kPa ECM stiffness repressed the expression and nuclear accumulation of Yes-associated protein (YAP) to regulate the expression of Serine/Arginine Splicing Factor 1 (SRSF1) via Runt-related transcription factor 2 (RUNX2), which may then subsequently induce the expression and secretion of VEGF₁₆₅ in NB tumor cells. Through implantation of 3D col-Tgels with different stiffness into nude mice, the inhibitory effect of 30 kPa on NB angiogenesis was confirmed in vivo. Furthermore, we found that the inhibitory effect of 30 kPa stiffness on NB angiogenesis was reversed by YAP overexpression, suggesting the important role of YAP in NB angiogenesis regulated by ECM stiffness. Overall, our work not only showed a regulatory effect of ECM stiffness on NB angiogenesis, but also revealed a new signaling axis, YAP-RUNX2-SRSF1, that mediates angiogenesis by regulating the expression and secretion of VEGF₁₆₅ from NB cells. ECM stiffness and the potential molecules revealed in the present study may be new therapeutic targets for NB angiogenesis.

Hippo Signaling Pathway in Pancreas Development

The Hippo signaling pathway is a vital regulator of pancreatic development and homeostasis, directing cell fate decisions, morphogenesis, and adult pancreatic cellular plasticity. Through loss-of-function research, Hippo signaling has been found to play key roles in maintaining the proper balance between progenitor cell renewal, proliferation, and differentiation in pancreatic organogenesis. Other studies suggest that overactivation of YAP, a downstream effector of the pathway, promotes ductal cell development and suppresses endocrine cell fate specification via repression of Ngn3. After birth, disruptions in Hippo signaling have been found to lead to de-differentiation of acinar cells and pancreatitis-like phenotype. Further, Hippo signaling directs pancreatic morphogenesis by ensuring proper cell polarization and branching. Despite these findings, the mechanisms through which Hippo governs cell differentiation and pancreatic architecture are yet to be fully understood. Here, we review recent studies of Hippo functions in pancreatic development, including its crosstalk with NOTCH, WNT/β-catenin, and PI3K/Akt/mTOR signaling pathways.

Chinese Propolis Suppressed Pancreatic Cancer Panc-1 Cells Proliferation and Migration via Hippo-YAP Pathway

Pancreatic cancer is one of the most malignant cancers with high mortality. Therefore, it is of great urgency to develop new agents that could improve the prognosis of Pancreatic cancer patients. Chinese propolis (CP), a flavonoid-rich beehive product, has been reported to have an anticancer effect. In this study, we applied CP to the human Pancreatic cancer cell line Panc-1 to verify its impact on tumor development. CP induced apoptosis in Panc-1 cells from 12.5 µg/mL in a time- and dose-dependent manner with an IC₅₀ value of approximately 50 µg/mL. Apoptosis rate induced by CP was examined by Annexing FITC/PI assay. We found that 48 h treatment with 50 µg/mL CP resulted in 34.25 ± 3.81% apoptotic cells, as compared to 9.13 ± 1.76% in the control group. We further discovered that the Panc-1 cells tended to be arrested at G2/M phase after CP treatment, which is considered to contribute to the anti-proliferation effect of CP. Furthermore, our results demonstrated that CP suppressed Panc-1 cell migration by regulating epithelial-mesenchymal transition (EMT). Interestingly, the Hippo pathway was activated in Panc-1 cells after CP treatment, serving as a mechanism for the anti-pancreatic cancer effect of CP. These findings provide a possibility of beehive products as an alternative treatment for pancreatic cancer.

Regulatory effect of microRNA-223-3p on breast cancer cell processes via the Hippo/Yap signaling pathway

According to the 2018 global cancer statistics, the incidence and mortality rates of breast cancer are increasing gradually, which seriously threatens the health of women. MicroRNA-223-3p (miR-223-3p) can promote the proliferation and invasion of breast cancer cells. Hippo/Yes-related protein (Yap) signaling pathway activation has been found in a variety of tumors. The present study aimed to investigate the potential mechanism of miR-223-3p in breast cancer. The Cell Counting Kit-8 assay was used to detect cell viability and flow cytometry was used to detect apoptosis. The abilities of cell migration and invasion were detected using scratch and Transwell assays, as well as reverse transcription-quantitative PCR and western blotting to detect gene and protein expression, respectively. The current results demonstrated that miR-223-3p transcription levels were increased in breast cancer cells, and inhibition of miR-223-3p gene expression decreased cell proliferation, migration and invasion. Additionally, inhibition of miR-223-3p expression inhibited epithelial-mesenchymal transition (EMT) in breast cancer cells. miR-223-3p promoted cell proliferation, migration, invasion and EMT, and the western blotting results demonstrated that miR-223-3p inhibition increased the phosphorylation of Yap1 and the protein expression levels of large tumor suppressor kinase 1. In conclusion, results from the present results suggested that miR-223-3p may promote cell proliferation, migration, invasion and EMT through the Hippo/Yap signaling pathway. Therefore, miR-223-3p may be a potential biomarker for breast cancer.

Overexpressed WDR3 induces the activation of Hippo pathway by interacting with GATA4 in pancreatic cancer

BACKGROUND

WD repeat domain 3 (WDR3) is involved in a variety of cellular processes including gene regulation, cell cycle progression, signal transduction and apoptosis. However, the biological role of WDR3 in pancreatic cancer and the associated mechanism remains unclear. We seek to explore the immune-independent functions and relevant mechanism for WDR3 in pancreatic cancer.

METHODS

The GEPIA web tool was searched, and IHC assays were conducted to determine the mRNA and protein expression levels of WDR3 in pancreatic cancer patients. MTS, colony formation, and transwell assays were conducted to determine the biological role of WDR3 in human cancer. Western blot analysis, RT-qPCR, and immunohistochemistry were used to detect the expression of specific genes. An immunoprecipitation assay was used to explore protein-protein interactions.

RESULTS

Our study proved that overexpressed WDR3 was correlated with poor survival in pancreatic cancer and that WDR3 silencing significantly inhibited the proliferation, invasion, and tumor growth of pancreatic cancer. Furthermore, WDR3 activated the Hippo signaling pathway by inducing yes association protein 1 (YAP1) expression, and the combination of WDR3 silencing and administration of the YAP1 inhibitor TED-347 had a synergistic inhibitory effect on the progression of pancreatic cancer. Finally, the upregulation of YAP1 expression induced by WDR3 was dependent on an interaction with GATA binding protein 4 (GATA4), the transcription factor of YAP1, which interaction induced the nuclear translocation of GATA4 in pancreatic cancer cells.

CONCLUSIONS

We identified a novel mechanism by which WDR3 plays a critical role in promoting pancreatic cancer progression by activating the Hippo signaling pathway through the interaction with GATA4. Therefore, WDR3 is potentially a therapeutic target for pancreatic cancer treatment.

YAP in pancreatic cancer: oncogenic role and therapeutic strategy

Pancreatic cancer, especially pancreatic ductal adenocarcinoma (PDAC), remains a fatal disease with few efficacious treatments. The Hippo signaling pathway, an evolutionarily conserved signaling module, plays critical roles in tissue homeostasis, organ size control and tumorigenesis. The transcriptional coactivator yes-associated protein (YAP), a major downstream effector of the Hippo pathway, is associated with various human cancers including PDAC. Considering its importance in cancer, YAP is emerging as a promising therapeutic target. In this review, we summarize the current understanding of the oncogenic role and regulatory mechanism of YAP in PDAC, and the potential therapeutic strategies targeting YAP.

TRPS1 and YAP1 Regulate Cell Proliferation and Drug Resistance of Osteosarcoma via Competitively Binding to the Target of circTADA2A - miR-129-5p

Introduction

The yes-associated protein (YAP) and trichorhinophalangeal syndrome 1 (TRPS1) have been reported to account for the pathogenesis of cancers and may play an important role in osteosarcoma (OS). This study intended to investigate the modulatory effect and relationship of TRPS1 and YAP1 in OS cells.

Methods

The expression difference of YAP1 and TRPS1 in OS cells was measured. Then, the effect of circTADA2A silence on YAP1 and TRPS1 expression as well as OS proliferation and drug resistance was estimated.

Results

TRPS1 and YAP1 were upregulated in OS cell lines, and TRPS1 and YAP1 were highly expressed in MG63 and U2OS cells, respectively. The cell proliferation of MG63 was lower than that of U2OS, but the opposite result was observed in the presence of cisplatin (DDP). CircTADA2A was upregulated while miR-129-5p was downregulated in MG63 and U2OS cells compared. Besides, circTADA2A knockdown inhibited cell proliferation and reduced DDP resistance in both MG63 and U2OS. MiR-129-5p was increased but TRPS1 and YAP1 were decreased by circTADA2A knockdown. Meanwhile, circTADA2A knockdown reduced TRPS1 protein expression but enhanced phosphorylated (p)-YAP1. In xenograft OS tumor mice, circTADA2A knockdown inhibited tumor growth in the absence or presence of DDP. Finally, miR-129-5p could bind to circTADA2A, TRPS1 and YAPS.

Discussion

CircRNA TADA2A could target miR-129-5p, which was competitively bound by TRPS1 and YAP1, thereby regulating OS cell proliferation and drug resistance.

Regulation of ABCG2 expression by Wnt5a through FZD7 in human pancreatic cancer cells

ATP-binding cassette subfamily G member 2 (ABCG2), a member of the ABC transporter superfamily, has been implicated in the development of chemotherapeutic drug resistance in cancer cells. However, the regulators of ABCG2 expression and their roles in anticancer drug resistance have not been fully characterized, especially in the context of pancreatic cancer. The aim of the present study was to investigate whether ABCG2 contributed to drug resistance in pancreatic cancer and to elucidate its regulatory molecular pathways. Using immunohistochemical analysis of pancreatic ductal adenocarcinoma and adjacent healthy tissue samples, the present study identified a positive correlation between ABCG2 and Wnt5a, a member of the Wnt family of secreted proteins. It was also determined that treatment with recombinant human Wnt5a protein could upregulate the expression of ABCG2 in the Capan-2 human pancreatic cancer cell line and enhance its resistance to gemcitabine. The upregulation of ABCG2 by Wnt5a was inhibited by small interfering RNA silencing of Frizzled class receptor 7 (FZD7) or by FZD7 inhibitors. Moreover, both FZD7 silencing or inhibition of its function attenuated gemcitabine resistance induced by Wnt5a in Capan-2 cells. Therefore, the present findings suggested that Wnt5a and FZD7 acted as upstream regulators of ABCG2 expression and that FZD7 may be an essential factor for Wnt5a-induced gemcitabine resistance in pancreatic cancer cells.

Huaier extract restrains pancreatic cancer by suppressing Wnt/β-catenin pathway

Pancreatic cancer is a lethal disease, and new treatments need to be explored. Huaier extract is a traditional Chinese medicine that has been found to exert antitumor properties in some cancers. However, the role of Huaier extract in pancreatic cancer has not been examined. In this study, we found that the proliferation, migration, invasion and EMT (epithelial-mesenchymal transition) of pancreatic cancer cells were suppressed by treatment with Huaier extract and that apoptosis increased. We also observed that expression of β-catenin was inhibited by Huaier extract. Furthermore, an animal study showed that Huaier extract slowed tumor growth in pancreatic cancer. Our results reveal that Huaier extract suppresses pancreatic cancer by inhibiting Wnt/β-catenin pathway both in vitro and in vivo.

Lysine demethylase 2 (KDM2B) regulates hippo pathway via MOB1 to promote pancreatic ductal adenocarcinoma (PDAC) progression

Background

Mps1 binding protein (MOB1) is one of the core components of the mammalian Hippo pathway and plays important roles in cancer development. However, its expression, function and regulation in pancreatic ductal adenocarcinoma (PDAC) have not been revealed yet.

Methods

The expression of MOB1 and lysine demethylase 2B (KDM2B) in PDAC and adjacent normal pancreas tissues were measured. Also, the underlying mechanisms of altered MOB1 expression and its impact on PDAC biology were investigated.

Results

We revealed for the first time that MOB1 was decreased expression in PDAC and was a statistically significant independent predictor of poor survival, and restored expression of MOB1 suppressed the proliferation, migration and invasion of PDAC cells. Further studies demonstrated that KDM2B directly bound to the promoter region of MOB1, and suppressed the promoter activity of MOB1 and transcriptionally inhibited the MOB1 expression. Furthermore, KDM2B regulated Hippo pathway and promoted PDAC proliferation, migration and invasion via MOB1.

Conclusion

This study demonstrated the mechanism and roles of a novel KDM2B/MOB1/Hippo signaling in PDAC progression.

YAP Inhibition by Nuciferine via AMPK-Mediated Downregulation of HMGCR Sensitizes Pancreatic Cancer Cells to Gemcitabine

Nuciferine, a major aporphine alkaloid constituent of lotus leaves, is a raw material for obesity treatment. Extensive studies have revealed that obesity is associated with pancreatic cancer (PC). However, it has not been clarified whether nuciferine could be used in PC treatment or prevention. Here, we show that nuciferine could enhance the sensitivity of PC cells to gemcitabine in both cultured cells and the xenograft mouse model. The mechanism study demonstrated that nuciferine induced YAP Ser127 phosphorylation [pYAP(Ser127)] through AMPK-mediated 3-hydroxy-3-methyl-glutaryl-coA reductase (HMGCR) downregulation. Remarkably, wild-type YAP overexpression or YAP Ser127 mutant could resist to nuciferine and no longer sensitize PC cells to gemcitabine. Knockdown of AMPK attenuated pYAP(Ser127) induced by nuciferine. Moreover, knockdown of AMPK reversed nuciferine-mediated HMGCR downregulation. Notably, HMGCR inhibiting could restrain YAP by phosphorylation Ser 127, and therefore enhance the efficiency of gemcitabine in PC cells. In line with this consistent, overexpression of HMGCR reduced growth inhibition caused by nuciferine and/or gemcitabine treatment in PC cells. In summary, these results provide an effective supplementary agent and suggest a therapeutic strategy to reduce gemcitabine resistance in PC.

Evolving trends in pancreatic cancer therapeutic development

Despite advances in translational research, the overall 5-year survival for pancreatic cancer remains dismal and with rising incidence pancreatic cancer is predicted to be the second leading cause of cancer death for many developed countries. Surgical intervention followed by cytotoxic chemotherapy are currently the best options for treatment, but disease recurrence is very common. Efforts to develop new therapeutic agents and delivery systems are necessary to achieve better clinical efficacy with less toxicity. Promising prospects are arising with new preclinical and clinical therapeutic strategies using small molecule targeted therapies, RNAi, stromal therapies, and immunotherapies. With a better understanding of the biology to aid target selection and discovery of biomarkers to aid precision medicine, better opportunities will evolve to shape the therapeutic landscape, enhance patient quality of life and increase overall survival.

Role of Hippo/YAP signaling in irradiation-induced glioma cell apoptosis

Background

Although Hippo/Yes-associated protein (YAP) signaling plays crucial roles in radiation sensitivity and resistance of multiple kinds of cancers, its role in the radiation sensitivity of glioma cells remains unclear. The present study aimed to reveal Hippo/YAP role in the radiation sensitivity of glioma cells.

Methods

Glioma U251 cells were administrated with different doses of irradiation. Cell Counting Kit-8 (CCK-8) and flow cytometry assays were used to assess cell viability and apoptosis. Co-immunoprecipitation (co-IP) assay was used to assess the interactions between proteins.

Results

The results showed that irradiation exposure significantly inhibited cell viability and induced cell apoptosis in a dose-dependent manner, as well as decreased YAP1 expression via enhancing RCHY1-mediated YAP1 protein degradation. In addition, we observed that downregulation of YAP1 or RCHY1 weakened the role of irradiation exposure in cell viability inhibition and apoptosis promotion.

Conclusion

Collectively, this study emphasizes the vital role of Hippo/YAP signaling in radiation sensitivity of glioma, that RCHY1-mediated YAP1 protein downregulation is a main mechanism accounting for radiation-induced glioma cell apoptosis. Our study may enrich the theoretical basis of Hippo/YAP signaling as a new target for improving radiation sensitivity in glioma.

Ezrin promotes pancreatic cancer cell proliferation and invasion through activating the Akt/mTOR pathway and inducing YAP translocation

Background

Ezrin and YAP are abnormally expressed in various cancers, and play pivotal roles in cancer initiation and development. However, the mechanisms of Ezrin in pancreatic cancer have not been fully elucidated. In this study, we aimed to elucidate the functions and mechanisms of Ezrin in the pathogenesis of pancreatic cancer.

Methods

Effects of Ezrin deregulation on pancreatic cancer phenotype were determined in Capan-1 and BxPC-3 cells using MTT, colony formation, transwell, wound-healing, and chick chorioallantoic membrane assays. To find out the underlying mechanism of Ezrin, multiple assays were performed to detect the effect of Ezrin on Akt pathway activation and YAP expression. Then, Ezrin and YAP expression was analyzed in pancreatic cancer and normal pancreas samples. Finally, the prognostic value of Ezrin and YAP was evaluated in pancreatic cancer patients.

Results

Ezrin promoted proliferation, invasion, epithelial–mesenchymal transition (EMT) progression, and angiogenesis of pancreatic cancers. Mechanistically, Ezrin activated Akt/mTOR pathways and induced YAP phosphorylation and nucleus translocation. The PI3K/Akt pathway inhibitor, rapamycin, and LY294002 could partially attenuate the effect of Ezrin on cell proliferation, invasion, EMT progression, and YAP phosphorylation and translocation. Moreover, both Ezrin and YAP were significantly overexpressed in pancreatic cancer tissues compared with adjacent normal pancreas, and correlated with poor prognosis in pancreatic cancer patients. Multivariate survival analysis showed that Ezrin was an independent prognostic marker for pancreatic cancer. Furthermore, the expression status of Ezrin and YAP had positive correlations in pancreatic cancer tissues.

Conclusion

Ezrin promoted pancreatic cancer proliferation, invasion, migration, and EMT progression, partially through activating the PI3K/Akt pathway, and also regulated YAP phosphorylation and translocation, partially through the PI3K/Akt pathway. Ezrin and YAP were significantly overexpressed in pancreatic cancers, and correlated with poor prognosis in pancreatic cancer patients.

High glucose microenvironment accelerates tumor growth via SREBP1-autophagy axis in pancreatic cancer

Background

Diabetes is recognized to be a risk factor of pancreatic cancer, but the mechanism has not been fully elucidated. Sterol regulatory element binding protein 1 (SREBP1) is an important transcription factor involved in both lipid metabolism and tumor progression. However, the relationship between high glucose microenvironment, SREBP1 and pancreatic cancer remains to be explored.

Methods

Clinical data and surgical specimens were collected. Pancreatic cancer cell lines BxPc-3 and MiaPaCa-2 were cultured in specified medium. Immunohistochemistry (IHC) and western blotting were performed to detect the expression of SREBP1. MTT and colony formation assays were applied to investigate cell proliferation. Immunofluorescence, mRFP-GFP adenoviral vector and transmission electron microscopy were performed to evaluate autophagy. We used streptozotocin (STZ) to establish a high glucose mouse model for the in vivo study.

Results

We found that high blood glucose levels were associated with poor prognosis in pancreatic cancer patients. SREBP1 was overexpressed in both pancreatic cancer tissues and pancreatic cancer cell lines. High glucose microenvironment promoted tumor proliferation, suppressed apoptosis and inhibited autophagy level by enhancing SREBP1 expression. In addition, activation of autophagy accelerated SREBP1 expression and suppressed apoptosis. Moreover, high glucose promotes tumor growth in vivo by enhancing SREBP1 expression.

Conclusion

Our results indicate that SREBP1-autophagy axis plays a crucial role in tumor progression induced by high glucose microenvironment. SREBP1 may represent a novel target for pancreatic cancer prevention and treatment.

Jiedu Sangen Decoction Inhibits the Invasion and Metastasis of Colorectal Cancer Cells by Regulating EMT through the Hippo Signaling Pathway

Colorectal cancer (CRC) is one of the most common malignant tumors affecting the digestive tract. Moreover, the invasion and metastasis of CRC are the main reason therapy is usually inefficient. Decreased intercellular adhesion and enhanced cell motility induced by epithelial-mesenchymal transition (EMT) provide the basic conditions for the invasion and metastasis of the epithelial tumor cells of CRC. The Jiedu Sangen Decoction (JSD) is a prescription that has been used for more than 50 years in the treatment of CRC in the Zhejiang Hospital of Traditional Chinese Medicine. The aim of this study was to investigate the mechanism of JSD-triggered inhibition of invasion and metastasis in colon cancer. In vitro, the EMT model of the SW480 cells was induced by using epithelial growth factor (50 ng/mL). In vivo, the murine model of liver metastasis was constructed by inoculating mice with the SW480 cells. The effects of JSD on cell migration, invasion, and proliferation were determined using the transwell assay and CCK-8 assay. Moreover, the proteins related to the EMT process and the Hippo signaling pathway in the cancerous tissues and cell lines were determined by western blotting and immunostaining. JSD could significantly inhibit the proliferation, migration, and invasion of CRC cells and reverse their EMT status (all, P < 0.05). Moreover, after intervention with JSD, the levels of E-Cadherin (E-cad) increased, whereas the expression levels of N-Cadherin (N-cad), Yes-associated protein (YAP), and the transcriptional coactivator with the PDZ-binding motif (TAZ) decreased in both the SW480 cells and the tumor tissues. In summary, JSD reversed EMT and inhibited the invasion and metastasis of CRC cells through the Hippo signaling pathway.

VASN promotes YAP/TAZ and EMT pathway in thyroid carcinogenesis in vitro

BACKGROUND

Thyroid cancer incidence has been continuity growing globally. To Find reliable molecular biomarkers to assess prognosis and select optimal treatment is necessary. VASN is a protein-coding gene that plays a vital part in tumor development and angiogenesis. Analyzing the TCGA dates, we found VASN could be a potential marker in assessing thyroid prognosis. The act of VASN in thyroid cancer is not explicit. In this article, we investigate the function of VASN expression in thyroid cancer.

METHODS

The Cancer Genome Atlas (TCGA) unpaired thyroid cancer and normal RNA-seq data was download and our paired thyroid cancer, and a polymerase chain reaction analyzed normal samples. The expression of VASN was regulated by transfected small interfering RNA, and the function of VASN was determined through migration, invasion and cell proliferation assays. Western blot assay was performed to reveal the relation between the VASN expression and YAP/TAZ pathway, epithelial-mesenchymal transition in thyroid carcinogenesis.

RESULTS

The significant upregulation of VASN in papillary thyroid carcinoma tissues associated to normal thyroid tissues was revealed by our data and TCGA data. VASN overexpression was significantly correlated to lymph node metastasis, tumor stage and tumor size. In the cell, experiments showed that VASN low expression significantly suppressed the migration, invasion, and proliferation. Western blot assay proves the effect of VASN expression on YAP/TAZ pathway and epithelial-mesenchymal transition.

CONCLUSION

VASN plays a crucial oncogene in thyroid cancer. Our results indicate that VASN could be a biomarker of thyroid cancer and may act in the YAP/TAZ pathway to regulate epithelial-mesenchymal transition (EMT).

Activated Fibroblast Program Orchestrates Tumor Initiation and Progression; Molecular Mechanisms and the Associated Therapeutic Strategies

: Neoplastic epithelial cells coexist in carcinomas with various non-neoplastic stromal cells, together creating the tumor microenvironment. There is a growing interest in the cross-talk between tumor cells and stromal fibroblasts referred to as carcinoma-associated fibroblasts (CAFs), which are frequently present in human carcinomas. CAF populations extracted from different human carcinomas have been shown to possess the ability to influence the hallmarks of cancer. Indeed, several mechanisms underlying CAF-promoted tumorigenesis are elucidated. Activated fibroblasts in CAFs are characterized as alpha-smooth muscle actin-positive myofibroblasts and actin-negative fibroblasts, both of which are competent to support tumor growth and progression. There are, however, heterogeneous CAF populations presumably due to the diverse sources of their progenitors in the tumor-associated stroma. Thus, molecular markers allowing identification of bona fide CAF populations with tumor-promoting traits remain under investigation. CAFs and myofibroblasts in wound healing and fibrosis share biological properties and support epithelial cell growth, not only by remodeling the extracellular matrix, but also by producing numerous growth factors and inflammatory cytokines. Notably, accumulating evidence strongly suggests that anti-fibrosis agents suppress tumor development and progression. In this review, we highlight important tumor-promoting roles of CAFs based on their analogies with wound-derived myofibroblasts and discuss the potential therapeutic strategy targeting CAFs.

ATDC is required for the initiation of KRAS-induced pancreatic tumorigenesis

Pancreatic adenocarcinoma (PDA) is an aggressive disease driven by oncogenic KRAS and characterized by late diagnosis and therapeutic resistance. Here we show that deletion of the ataxia-telangiectasia group D-complementing (Atdc) gene, whose human homolog is up-regulated in the majority of pancreatic adenocarcinoma, completely prevents PDA development in the context of oncogenic KRAS. ATDC is required for KRAS-driven acinar-ductal metaplasia (ADM) and its progression to pancreatic intraepithelial neoplasia (PanIN). As a result, mice lacking ATDC are protected from developing PDA. Mechanistically, we show ATDC promotes ADM progression to PanIN through activation of β-catenin signaling and subsequent SOX9 up-regulation. These results provide new insight into PDA initiation and reveal ATDC as a potential target for preventing early tumor-initiating events.

3D models in the new era of immune oncology: focus on T cells, CAF and ECM

Immune checkpoint inhibitor therapy has changed clinical practice for patients with different cancers, since these agents have demonstrated a significant improvement of overall survival and are effective in many patients. However, an intrinsic or acquired resistance frequently occur and biomarkers predictive of responsiveness should help in patient selection and in defining the adequate treatment options. A deep analysis of the complexity of the tumor microenvironment is likely to further advance the field and hopefully identify more effective combined immunotherapeutic strategies. Here we review the current knowledge on tumor microenvironment, focusing on T cells, cancer associated fibroblasts and extracellular matrix. The use of 3D cell culture models to resemble tumor microenvironment landscape and to screen immunomodulatory drugs is also reviewed.

Tankyrase1 antisense oligodeoxynucleotides suppress the proliferation, migration and invasion through Hippo/YAP pathway in human osteosarcoma cells

Osteosarcoma is the most common malignant tumor of bone with a high potential for metastasis and poor prognosis. This study intends to explore the effect of tankyrase1 (TANK1) in the development of osteosarcoma cells and the underlying mechanism. The osteosarcoma cell line MG-63 cells were cultured and transfected with tankyrase1 antisense oligodeoxynucleotides (TANK1-ASODN). Cell proliferation was detected with CCK-8 and immunofluorescence. Cell migration and invasion were examined by wound healing assay and Transwell assay, respectively. Reverse transcription-quantitative polymerase chain reaction was performed to detect the mRNA level of TANK1 and western blot was conducted to detect relative protein expression during the research. As a result, we demonstrated that TANK1 was upregulated in osteosarcoma. The TANK1-ASODN inhibited MG-63 cell proliferation, migration and invasion. The progress of epithelial-mesenchymal transition (EMT) was also suppressed in TANK1-ASODN transfected MG-63 cells compared to control group. Besides, the TANK1-ASODN activated and modulated the Hippo/YAP signaling which might be the pathway that TANK1 depended on. Overall, our finding supported that TANK1-ASODN slowed down the progress of osteosarcoma by suppressing cell proliferation, migration, invasion and EMT through Hippo/YAP pathway.

Emerging roles of YAP/TAZ in lung physiology and diseases

The YAP and TAZ, as the downstream effectors of Hippo pathway, have emerged as important translational co-activators of a wide variety of biological processes. YAP/TAZ plays a crucial role in the lung development and physiology. Dysregulation of YAP/TAZ signaling pathway contributes to the development and progression of chronic lung diseases, including lung cancer, pulmonary fibrosis, pulmonary hypertension, COPD, asthma, and lung infection. Therefore, owing to its critical functions, delineation of the signaling mechanisms of YAP/TAZ in pathological conditions will shed light on developing strategies for its therapeutic targeting. Currently, the complex regulation of this pathway is under extensive investigation. In this review, we summarize and present recent findings of molecular mechanisms of YAP/TAZ in the lung physiological and pathological conditions, as well as the implications of YAP/TAZ for lung diseases treatment and regeneration.