Pancreatic tumor microenvironment confers highly malignant properties on pancreatic cancer cells

Targeting the pancreatic tumor microenvironment by plant-derived products and their nanoformulations

Pancreatic cancer remains a significant health issue with limited treatment options. The tumor stroma, a complex environment made up of different cells and proteins, plays a crucial role in tumor growth and chemoresistance. Targeting tumor stroma, consisting of diverse non-tumor cells such as fibroblasts, extracellular matrix (ECM), immune cells, and also pre-vascular cells is encouraging for remodeling solid cancers, such as pancreatic cancer. Remodeling the stroma of pancreas tumors can be suggested as a strategy for reducing resistance to chemo/immunotherapy. Several studies have shown that phytochemicals from plants can affect the tumor environment and have anti-cancer properties. By targeting key pathways involved in stromal activation, phytochemicals may disrupt communication between the tumor and stroma and make tumor cells more sensitive to different treatments. Additionally, phytochemicals have immunomodulatory and anti-angiogenic properties, all of which contribute to their potential in treating pancreatic cancer. This review will provide a detailed look at how phytochemicals impact the tumor stroma and their effects on pancreatic tumor growth, spread, and response to treatment. It will also explore the potential of combining phytochemicals with other treatment options like chemotherapy, immunotherapy, and radiation.

Multisite Is Superior to Single-Site Intratumoral Chemotherapy to Retard the Outcomes of Pancreatic Ductal Adenocarcinoma in a Murine Model

INTRODUCTION

Locally advanced unresectable pancreatic cancer (LAPC) has a dismal prognosis, with intratumoral therapies showing limited benefits. We assume that the dense stroma within these tumors hampers drug dispersion.

AIM

This study explores the efficacy of multisite intratumoral injections in improving a drug's distribution while minimizing its side effects.

METHODS AND RESULTS

In mice with orthotopic LAPC tumors, weekly intratumoral injections of oxaliplatin at four separate sites reduced the tumor growth by 46% compared with saline (p < 0.003). Oxaliplatin exhibited the greatest impact on the tumor microenvironment relative to gemcitabine, Abraxane, or their combination, with increased necrosis, apoptosis, fibroblasts, inflammation, and infiltrating lymphocytes (p < 0.008). When combined with intravenous FOLFIRINOX (FFX), multisite intratumoral oxaliplatin reduced the tumor weight by 35% compared with single-site injection (p = 0.007). No additional visible toxicity was observed even at a 10-fold occurrence of intratumoral treatment. This co-modality treatment significantly improved survival compared with other groups (p = 0.007).

CONCLUSIONS

Multisite intratumoral therapy in tandem with systemic treatment holds promise for reducing the tumor size and enhancing the overall survival in LAPC.

Netrin-1 feedforward mechanism promotes pancreatic cancer liver metastasis via hepatic stellate cell activation, retinoid, and ELF3 signaling

The biology of metastatic pancreatic ductal adenocarcinoma (PDAC) is distinct from that of the primary tumor due to changes in cell plasticity governed by a distinct transcriptome. Therapeutic strategies that target this distinct biology are needed. We detect an upregulation of the neuronal axon guidance molecule Netrin-1 in PDAC liver metastases that signals through its dependence receptor (DR), uncoordinated-5b (Unc5b), to facilitate metastasis in vitro and in vivo. The mechanism of Netrin-1 induction involves a feedforward loop whereby Netrin-1 on the surface of PDAC-secreted extracellular vesicles prepares the metastatic niche by inducing hepatic stellate cell activation and retinoic acid secretion that in turn upregulates Netrin-1 in disseminated tumor cells via RAR/RXR and Elf3 signaling. While this mechanism promotes PDAC liver metastasis, it also identifies a therapeutic vulnerability, as it can be targeted using anti-Netrin-1 therapy to inhibit metastasis using the Unc5b DR cell death mechanism.

The ALOX5 inhibitor Zileuton regulates tumor-associated macrophage M2 polarization by JAK/STAT and inhibits pancreatic cancer invasion and metastasis

5-lipoxygenase (encoded by ALOX5) plays an important role in immune regulation. Zileuton is currently the only approved ALOX5 inhibitor. However, the mechanisms of ALOX5 and Zileuton in progression of pancreatic cancer remain unclear. Therefore, we investigated the effects of Zileuton on tumor-associated macrophage M2 polarization and pancreatic cancer invasion and metastasis, both in vivo and in vitro. In bulk RNA sequencing (RNA-seq) and single-cell RNA sequencing (scRNA-seq) analyses, we found a significant association between elevated levels of ALOX5 and poor survival, adverse stages, M2 macrophage infiltration, and the activation of JAK/STAT pathways in macrophages. In clinical samples, immunofluorescence, quantitative real-time PCR and immunohistochemical results verified the high expression of ALOX5 in pancreatic cancer, primarily in macrophages. We constructed PANC-1 human pancreatic cancer cells and macrophages overexpressing ALOX5 using lentivirus. In PANC-1 pancreatic cancer cells, low-dose Zileuton inhibited PANC-1 cell invasion and migration by blocking ALOX5. In macrophages, ALOX5 induced the M2-like phenotype through the JAK/STAT pathway and promoted the chemotaxis of macrophages towards PANC-1 cells, while Zileuton can inhibit these effects. We constructed the nude mouse model of in situ transplantation tumor of pancreatic cancer. After treatment with Zileuton, the mice showed increased survival rates and reduced liver metastasis. These findings indicate that ALOX5 regulates tumor-associated macrophage M2 polarization via the JAK/STAT pathway and promotes invasion and metastasis in pancreatic cancer. Zileuton can inhibit these effects by inhibiting ALOX5. These results provide a theoretical basis for the potential use of Zileuton in the treatment of pancreatic cancer.

Gradient Tumor Microenvironment-Promoted Penetrating Micelles for Hypoxia Relief and Immunosuppression Reversion in Pancreatic Cancer Treatment

The tumor microenvironment of pancreatic ductal adenocarcinoma (PDAC) is the main block for the penetration of chemotherapy. In the tumor microenvironment, a dense matrix composed of fibrin is formed on the exterior, while the interior is featured by high reduction, hypoxia and low pH. How to match the special microenvironment to on-demand drug release is the key to improve chemotherapeutic efficacy. Herein, a microenvironment-responsive micellar system is developed to deepen tumoral penetration. Briefly, the conjugation of a fibrin-targeting peptide to PEG-poly amino acid has been utilized to achieve accumulation of micelles in the tumor stroma. By modification of micelles with hypoxia-reducible nitroimidazole which becomes protonated under acidic conditions, their surface charge is more positive, facilitating deeper penetration into tumors. Paclitaxel was loaded onto the micelles via a disulfide bond to enable glutathione (GSH)-responsive release. Therefore, the immunosuppressive microenvironment is relived through the alleviation of hypoxia and depletion of GSH. Hopefully, this work could establish paradigms by designing sophisticated drug-delivery systems to tactfully employ and retroact the tamed tumoral microenvironment to improve the therapeutic efficacy based on understanding the multiple hallmarks and learning the mutual regulation. STATEMENT OF SIGNIFICANCE: : Tumor microenvironment(TME) is an unique pathological feature of pancreatic cancer and an inherent barrier to chemotherapy. Numerous studies regard TME as the targets for drug delivery. In this work, we propose a hypoxia-responsive nanomicellar drug delivery system that aiming hypoxia TME of pancreatic cancer. The nanodrug delivery system could respond to the hypoxic microenvironment and enhance the penetration of the inner tumor at the same time preserving the outer tumor stroma, thus achieving targeted treatment of PDAC by preserving the integrity of the outer stroma. Simultaneously, the responsive group can reverse the degree of hypoxia in TME by disrupting the redox balance in the tumor region, thus achieving precise treatment of PDAC by matching the pathological characteristics of TME. We believe our article would provide new design ideas for the future treatments for pancreatic cancer.

Extracellular Vesicles Derived from Human Umbilical Cord Mesenchymal Stromal Cells as an Efficient Nanocarrier to Deliver siRNA or Drug to Pancreatic Cancer Cells

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers worldwide. Treatment of PDAC remains a major challenge. This study aims to evaluate, in vitro, the use of human umbilical cord mesenchymal stromal cell (UC-MSC)-derived EVs to specifically target pancreatic cancer cells. EVs were isolated from the FBS-free supernatants of the cultured UC-MSCs by ultracentrifugation and characterized by several methods. EVs were loaded with scramble or KRAS^G12D-targeting siRNA by electroporation. The effects of control and loaded EVs on different cell types were evaluated by assessing cell proliferation, viability, apoptosis and migration. Later, the ability of EVs to function as a drug delivery system for doxorubicin (DOXO), a chemotherapeutic drug, was also evaluated. Loaded EVs exhibited different kinetic rates of uptake by three cell lines, namely, BxPC-3 cells (pancreatic cancer cell line expressing KRAS^wt), LS180 cells (colorectal cell line expressing KRAS^G12D) and PANC-1 cells (pancreatic cell line expressing KRAS^G12D). A significant decrease in the relative expression of the KRAS^G12D gene after incubation with KRAS siRNA EVs was observed by real-time PCR. KRAS^G12D siRNA EVs significantly reduced the proliferation, viability and migration of the KRAS^G12D cell lines compared to scramble siRNA EVs. An endogenous EV production method was applied to obtain DOXO-loaded EVs. Briefly, UC-MSCs were treated with DOXO. After 24 h, UC-MSCs released DOXO-loaded EVs. DOXO-loaded EVs were rapidly taken up by PANC-1 cells and induced apoptotic cell death more efficiently than free DOXO. In conclusion, the use of UC-MSC-derived EVs as a drug delivery system for siRNAs or drugs could be a promising approach for the targeted treatment of PDAC.

Deciphering the involvement of the Hippo pathway co-regulators, YAP/TAZ in invadopodia formation and matrix degradation

Invadopodia are adhesive, actin-rich protrusions formed by metastatic cancer cells that degrade the extracellular matrix and facilitate invasion. They support the metastatic cascade by a spatially and temporally coordinated process whereby invading cells bind to the matrix, degrade it by specific metalloproteinases, and mechanically penetrate diverse tissue barriers by forming actin-rich extensions. However, despite the apparent involvement of invadopodia in the metastatic process, the molecular mechanisms that regulate invadopodia formation and function are still largely unclear. In this study, we have explored the involvement of the key Hippo pathway co-regulators, namely YAP, and TAZ, in invadopodia formation and matrix degradation. Toward that goal, we tested the effect of depletion of YAP, TAZ, or both on invadopodia formation and activity in multiple human cancer cell lines. We report that the knockdown of YAP and TAZ or their inhibition by verteporfin induces a significant elevation in matrix degradation and invadopodia formation in several cancer cell lines. Conversely, overexpression of these proteins strongly suppresses invadopodia formation and matrix degradation. Proteomic and transcriptomic profiling of MDA-MB-231 cells, following co-knockdown of YAP and TAZ, revealed a significant change in the levels of key invadopodia-associated proteins, including the crucial proteins Tks5 and MT1-MMP (MMP14). Collectively, our findings show that YAP and TAZ act as negative regulators of invadopodia formation in diverse cancer lines, most likely by reducing the levels of essential invadopodia components. Dissecting the molecular mechanisms of invadopodia formation in cancer invasion may eventually reveal novel targets for therapeutic applications against invasive cancer.

Counteracting gemcitabine+nab-paclitaxel induced dysbiosis in KRAS wild type and KRASG12D mutated pancreatic cancer in vivo model

Pancreatic cancer (PC) has a very low survival rate mainly due to late diagnosis and refractoriness to therapies. The latter also cause adverse effects negatively affecting the patients' quality of life, often requiring dose reduction or discontinuation of scheduled treatments, compromising the chances of cure. We explored the effects of a specific probiotic blend on PC mice xenografted with KRAS wild-type or KRASG12D mutated cell lines alone or together with gemcitabine+nab-paclitaxel treatment to then assess tumor volume and clinical pathological variables. Beside a semi-quantitative histopathological evaluation of murine tumor and large intestine samples, histochemical and immunohistochemical analyses were carried out to evaluate collagen deposition, proliferation index Ki67, immunological microenvironment tumor-associated, DNA damage markers and also mucin production. Blood cellular and biochemical parameters and serum metabolomics were further analyzed. 16S sequencing was performed to analyze the composition of fecal microbiota. Gemcitabine+nab-paclitaxel treatment impaired gut microbial profile in KRAS wild-type and KRASG12D mice. Counteracting gemcitabine+nab-paclitaxel- induced dysbiosis through the administration of probiotics ameliorated chemotherapy side effects and decreased cancer-associated stromatogenesis. Milder intestinal damage and improved blood count were also observed upon probiotics treatment as well as a positive effect on fecal microbiota, yielding an increase in species richness and in short chain fatty acids producing- bacteria. Mice' serum metabolomic profiles revealed significant drops in many amino acids upon probiotics administration in KRAS wild-type mice while in animals transplanted with PANC-1 KRASG12D mutated all treated groups showed a sharp decline in serum levels of bile acids with respect to control mice. These results suggest that counteracting gemcitabine+nab-paclitaxel-induced dysbiosis ameliorates chemotherapy side effects by restoring a favorable microbiota composition. Relieving adverse effects of the chemotherapy through microbiota manipulation could be a desirable strategy in order to improve pancreatic cancer patients' quality of life and to increase the chance of cure.

Regenerative medicine: current research and perspective in pediatric surgery

The field of regenerative medicine, encompassing several disciplines including stem cell biology and tissue engineering, continues to advance with the accumulating research on cell manipulation technologies, gene therapy and new materials. Recent progress in preclinical and clinical studies may transcend the boundaries of regenerative medicine from laboratory research towards clinical reality. However, for the ultimate goal to construct bioengineered transplantable organs, a number of issues still need to be addressed. In particular, engineering of elaborate tissues and organs requires a fine combination of different relevant aspects; not only the repopulation of multiple cell phenotypes in an appropriate distribution but also the adjustment of the host environmental factors such as vascularisation, innervation and immunomodulation. The aim of this review article is to provide an overview of the recent discoveries and development in stem cells and tissue engineering, which are inseparably interconnected. The current status of research on tissue stem cells and bioengineering, and the possibilities for application in specific organs relevant to paediatric surgery have been specifically focused and outlined.

Cancer-associated fibroblasts-derived exosomes from chemoresistant patients regulate cisplatin resistance and angiogenesis by delivering VEGFA in colorectal cancer

The purpose of this study was to investigate the effect of chemoresistant cancer-associated fibroblasts (R-CAFs) against cisplatin (DDP) on colorectal cancer (CRC) progression. First, clinical tissue samples of chemoresistant or chemosensitive CRC patients were collected to isolate R-CAFs or chemosensitive CAFs (S-CAFs), respectively. HT29 cells or HUVECs were co-cultured with R-CAFs by transwell device. Then the proliferation and apoptosis of HT29 cells were detected with Cell Counting Kit-8 (CCK-8) and flow cytometry. Transwell assay and tube formation assay was used to detect the migration and angiogenesis of HUVECs. In addition, a colorectal cancer transplantation model was established subcutaneously in nude mice by injecting stably transfected HT29 cells and exosomes from different CAF groups, and then the tumor volume and weight were measured and recorded. Hematoxylin and eosin staining, immunohistochemistry, and terminal deoxynucleotidyl transferase dUTP Nick-End Labeling (TUNEL) staining were performed to characterize the histopathological characteristics and apoptosis level of tumor tissues, respectively. S-CAFs and R-CAFs were isolated successfully. HT29 cell co-culture with R-CAFs significantly affected the proliferation and apoptosis of HT29 cells. Exosomes derived from R-CAFs (R-CAFs-Exo) were delivered to HT29 cells, which could induce viability, suppress apoptosis and accelerate the angiogenesis of CRC. In addition, VEGFA was highly expressed in R-CAFs-Exo, which might indicate that R-CAFs could transmit VEGFA through exosomes. Overexpressed VEGFA in R-CAFs apparently regulates the viability, apoptosis, DDP resistance, and angiogenesis of CRC. In-vivo experiments confirmed that R-CAFs-Exo promoted the progression of CRC and DDP resistance by delivering VEGFA . R-CAFs-derived exosomes promote the viability, apoptosis, DDP resistance, and angiogenesis of CRC by delivering VEGFA .

MAPK4 silencing in gastric cancer drives liver metastasis by positive feedback between cancer cells and macrophages

Liver metastasis is a major cause of death in gastric cancer patients, but the underlying mechanisms are poorly understood. Through a combination of in vivo screening and transcriptome profiling followed by quantitative RT-PCR and tissue array analyses, we found that mitogen-activated protein kinase 4 (MAPK4) downregulation in gastric cancer tissues from patients is significantly associated with liver metastasis and poor prognosis. The knockdown of MAPK4 in gastric cancer cells promotes liver metastasis in orthotopic mouse models. MAPK4 depletion in gastric cancer cells induces the secretion of macrophage migration inhibitory factor (MIF) to polarize tumor-associated macrophages (TAMs) in orthotopic xenograft tumors. Moreover, TAMs activate epithelial-mesenchymal transition of gastric cancer cells to suppress MAPK4 expression, which further increases MIF secretion to polarize TAMs. Taken together, our results suggest a previously undescribed positive feedback loop between cancer cells and macrophages mediated by MAPK4 silencing that facilitates gastric cancer liver metastasis.

An analysis modality for vascular structures combining tissue-clearing technology and topological data analysis

The blood and lymphatic vasculature networks are not yet fully understood even in mouse because of the inherent limitations of imaging systems and quantification methods. This study aims to evaluate the usefulness of the tissue-clearing technology for visualizing blood and lymphatic vessels in adult mouse. Clear, unobstructed brain/body imaging cocktails and computational analysis (CUBIC) enables us to capture the high-resolution 3D images of organ- or area-specific vascular structures. To evaluate these 3D structural images, signals are first classified from the original captured images by machine learning at pixel base. Then, these classified target signals are subjected to topological data analysis and non-homogeneous Poisson process model to extract geometric features. Consequently, the structural difference of vasculatures is successfully evaluated in mouse disease models. In conclusion, this study demonstrates the utility of CUBIC for analysis of vascular structures and presents its feasibility as an analysis modality in combination with 3D images and mathematical frameworks.

Understanding blood and lymphatic vasculature networks is currently limited by existing imaging systems and quantification methods. Here the authors use the tissue clearing method CUBIC to generate 3D images, machine learning to capture the signals, and extract geometric features by topological data analysis.

Biological Characterization and Clinical Value of OAS Gene Family in Pancreatic Cancer

Background

OAS gene family plays an important role in antiviral process, but its role in pancreatic cancer has not yet been studied.

Methods

We analyzed the expression, prognostic value and biological function of the OAS gene family in human pancreatic cancer through comprehensive bioinformatic analysis and cellular level validation.

Results

OAS family was highly expressed in pancreatic cancer, and this high expression significantly affected the clinical stage and prognosis of the tumor. OAS gene family was closely related to the immune infiltration of pancreatic cancer, especially neutrophils and dendritic cells, and many immune-related factors and pathways are enriched in the tumor, such as type I interferon signaling pathway and NOD-like receptor signaling pathway.

Conclusion

Taken together, high expression of OAS family is closely related to poor prognosis of pancreatic cancer. OAS gene family may serve as the biomarker and even therapeutic target of pancreatic cancer.

Human amniotic fluid mesenchymal stem cells attenuate pancreatic cancer cell proliferation and tumor growth in an orthotopic xenograft mouse model

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a malignant cancer and chemotherapy ineffectively treats PDAC, leading to the requirement for alternative tumor-targeted treatment. Human amniotic fluid mesenchymal stem cells (hAFMSCs) have been revealed to suppress tumor growth in various cancers and they are a strong candidate for treating PDAC.

METHODS

To evaluate the effects of hAFMSCs on human pancreatic carcinoma cells (PANC1, AsPC1 and BxPC3 cell lines) and the possible mechanism involved, an in vitro cell coculture system was used. A PANC1 orthotopic xenograft mouse model was established and hAFMSCs were injected intravenously at 4 weeks post-xenograft.

RESULTS

An in vitro coculture assay showed that hAFMSCs inhibited PANC1 cell proliferation by inducing S phase cell cycle arrest and increased cell apoptosis in a time-dependent manner. In PANC1 cells, hAFMSCs caused the downregulation of Cyclin A and Cyclin B1 as well as the upregulation of p21 (CDKN1A) at 24 h post coculture. The upregulation of pro-apoptotic factors Caspase-3/-8 and Bax at 24 h post coculture reduced the migration and invasion ability of PANC1 cells through inhibiting the epithelial-mesenchymal transition (EMT) process. In a PANC1 orthotopic xenograft mouse model, a single injection of hAFMSCs showed significant tumor growth inhibition with evidence of the modulation of cell cycle and pro-apoptotic regulatory genes and various genes involved in matrix metallopeptidase 7 (MMP7) signaling-triggered EMT process. Histopathological staining showed lower Ki67 levels in tumors from hAFMSCs-treated mice.

CONCLUSIONS

Our data demonstrated that hAFMSCs strongly inhibit PDAC cell proliferation, tumor growth and invasion, possibly by altering cell cycle arrest and MMP7 signaling-triggered EMT.

Contrast-enhanced computed tomography radiomics and multilayer perceptron network classifier: an approach for predicting CD20+ B cells in patients with pancreatic ductal adenocarcinoma

PURPOSE

To develop and validate a machine-learning classifier based on contrast-enhanced computed tomography (CT) for the preoperative prediction of CD20⁺ B lymphocyte expression in patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

Overall, 189 patients with PDAC (n = 132 and n = 57 in the training and validation sets, respectively) underwent immunohistochemistry and radiomics feature extraction. The X-tile software was used to stratify them into groups with 'high' and 'low' CD20⁺ B lymphocyte expression levels. For each patient, 1409 radiomic features were extracted from volumes of interest and reduced using variance analysis and Spearman correlation analysis. A multilayer perceptron (MLP) network classifier was developed using the training and validation set. Model performance was determined by its discriminative ability, calibration, and clinical utility.

RESULTS

A log-rank test showed that the patients with high CD20⁺ B expression had significantly longer survival than those with low CD20⁺ B expression. The prediction model showed good discrimination in both the training and validation sets. For the training set, the area under the curve (AUC), sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 0.82 (95% CI 0.74-0.89), 92.42%, 57.58%, 0.75, 0.69, and 0.88, respectively; whereas these values for the validation set were 0.84 (95% CI 0.72-0.93), 86.21%, 78.57%, 0.83, 0.81, and 0.85, respectively.

CONCLUSION

The MLP network classifier based on contrast-enhanced CT can accurately predict CD20⁺ B expression in patients with PDAC.

Renalase is a novel tissue and serological biomarker in pancreatic ductal adenocarcinoma

Dysregulated expression of the secretory protein renalase can promote pancreatic ductal adenocarcinoma (PDAC) growth in animal models. We characterized renalase expression in premalignant and malignant PDAC tissue and investigated whether plasma renalase levels corresponded to clinical PDAC characteristics. Renalase immunohistochemistry was used to determine the presence and distribution of renalase in normal pancreas, chronic pancreatitis, PDAC precursor lesions, and PDAC tissues. Associations between pretreatment plasma renalase and PDAC clinical status were assessed in patients with varied clinical stages of PDAC and included tumor characteristics, surgical resection in locally advanced/borderline resectable PDAC, and overall survival. Data were retrospectively obtained and correlated using non-parametric analysis. Little to no renalase was detected by histochemistry in the normal pancreatic head in the absence of abdominal trauma. In chronic pancreatitis, renalase immunoreactivity localized to peri-acinar spindle-shaped cells in some samples. It was also widely present in PDAC precursor lesions and PDAC tissue. Among 240 patients with PDAC, elevated plasma renalase levels were associated with worse tumor characteristics, including greater angiolymphatic invasion (80.0% vs. 58.1%, p = 0.012) and greater node positive disease (76.5% vs. 56.5%, p = 0.024). Overall survival was worse in patients with high plasma renalase levels with median follow-up of 27.70 months vs. 65.03 months (p < 0.001). Renalase levels also predicted whether patients with locally advanced/borderline resectable PDAC underwent resection (AUC 0.674; 95%CI 0.42-0.82, p = 0.04). Overall tissue renalase was increased in both premalignant and malignant PDAC tissues compared to normal pancreas. Elevated plasma renalase levels were associated with advanced tumor characteristics, decreased overall survival, and reduced resectability in patients with locally advanced/borderline resectable PDAC. These studies show that renalase levels are increased in premalignant pancreatic tissues and that its levels in plasma correspond to the clinical behavior of PDAC.

Hsp70 modulates immune response in pancreatic cancer through dendritic cells

Heat shock protein 70 (Hsp70), a protein chaperone, is known to promote cell survival and tumor progression. However, its role in the tumor microenvironment (TME) is largely unknown. We specifically evaluated Hsp70 in the TME by implanting tumors in wild-type (WT) controls or Hsp70^-/- animals, thus creating a TME with or without Hsp70. Loss of Hsp70 led to significantly smaller tumors; there were no differences in stromal markers, but interestingly, depletion of CD8 + T-cells abrogated this tumor suppressive effect, indicating that loss of Hsp70 in the TME affects tumor growth through the immune cells. Compared to WT, adoptive transfer of Hsp70^-/- splenocytes exhibited greater antitumor activity in immunodeficient NSG and Rag 1^-/- mice. Hsp70^-/- dendritic cells showed increased expression of MHCII and TNF-α both in vitro and in vivo. These results suggest that the absence of Hsp70 in the TME inhibits tumors through increased dendritic cell activation. Hsp70 inhibition in DCs may emerge as a novel therapeutic strategy against pancreatic cancer.

A prognostic score based on long-term survivor unique transcriptomic signatures predicts patient survival in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is known for its poor prognosis with few long-term survivors. This study aimed to establish a prognostic score using unique transcriptomic profiles of long-term survivors to be used as a patient selection tool for meaningful clinical intervention in PDAC. In TCGA PDAC cohort, 16 genes were significantly upregulated in the long-term survivor tumors. A prognostic score was established using these 16 genes by LASSO Cox regression, and PHKG1, HOXA4, ISL2, DMRT3 and TRA2A gene expressions were included in the score. The prognostic value was confirmed in both testing and validation cohorts. The characteristics of the high score tumor was investigated by bioinformatical approach. The high score tumor was associated with TP53 mutation but not with other commonly enhanced signaling pathways in PDAC. The high score tumor was associated with higher tumor mutational burden and unfavorable tumor microenvironment (TME), such as lower infiltration of CD8-positive T cells and dendritic cells, and less cell composition of mature blood vessels and fibroblasts. The high score tumor was also associated with enhanced cell proliferation and margin positivity after surgery. The impact of score component genes on the cell proliferation was investigated by in vitro experiments. Silencing of the score component genes promoted cell proliferation. In conclusion, the prognostic score predicted PDAC patient survival and was associated with cancer aggressiveness such as unfavorable TME and enhanced cell proliferation.

Stem Cells in the Exocrine Pancreas during Homeostasis, Injury, and Cancer

Simple Summary

Pancreatic cancer is one of the most lethal malignancies. Hence, improved therapies are urgently needed. Recent research indicates that pancreatic cancers depend on cancer stem cells (CSCs) for tumor expansion, metastasis, and therapy resistance. However, the exact functionality of pancreatic CSCs is still unclear. CSCs have much in common with normal pancreatic stem cells that have been better, albeit still incompletely, characterized. In this literature review, we address how pancreatic stem cells influence growth, homeostasis, regeneration, and cancer. Furthermore, we outline which intrinsic and extrinsic factors regulate stem cell functionality during these different processes to explore potential novel targets for treating pancreatic cancer.

Abstract

Cell generation and renewal are essential processes to develop, maintain, and regenerate tissues. New cells can be generated from immature cell types, such as stem-like cells, or originate from more differentiated pre-existing cells that self-renew or transdifferentiate. The adult pancreas is a dormant organ with limited regeneration capacity, which complicates studying these processes. As a result, there is still discussion about the existence of stem cells in the adult pancreas. Interestingly, in contrast to the classical stem cell concept, stem cell properties seem to be plastic, and, in circumstances of injury, differentiated cells can revert back to a more immature cellular state. Importantly, deregulation of the balance between cellular proliferation and differentiation can lead to disease initiation, in particular to cancer formation. Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease with a 5-year survival rate of only ~9%. Unfortunately, metastasis formation often occurs prior to diagnosis, and most tumors are resistant to current treatment strategies. It has been proposed that a specific subpopulation of cells, i.e., cancer stem cells (CSCs), are responsible for tumor expansion, metastasis formation, and therapy resistance. Understanding the underlying mechanisms of pancreatic stem cells during homeostasis and injury might lead to new insights to understand the role of CSCs in PDAC. Therefore, in this review, we present an overview of the current literature regarding the stem cell dynamics in the pancreas during health and disease. Furthermore, we highlight the influence of the tumor microenvironment on the growth behavior of PDAC.

Heterogenous expression of endoglin marks advanced renal cancer with distinct tumor microenvironment fitness

Intratumoral heterogeneity, including in clear cell renal cell carcinoma, is a potential cause of drug resistance and metastatic cancer progression. We specified the heterogeneous population marked by endoglin (also known as CD105) in a preclinical model of clear cell renal cell carcinoma progression. Highly malignant derivatives of human clear cell renal cell carcinoma OS‐RC‐2 cells were established as OS5Ks by serial orthotopic inoculation in our previous study. Expression of both ENG (encoding endoglin) mRNA and protein were heterogeneously upregulated in OS5Ks, and the endoglin‐positive (ENG⁺) population exhibited growth dependency on endoglin in anchorage‐independent cultures. Despite the function of endoglin as a type III receptor, transforming growth factor β and bone morphogenetic protein‐9 signaling were unlikely to contribute to the proliferative phenotype. Although endoglin has been proposed as a marker for renal cancer‐initiating cells, the OS5K‐3 ENG⁺ population did not enrich other reported cancer‐initiating cell markers or differentiate into the ENG^– population. Mouse tumor inoculation models revealed that the tumor‐forming capabilities of OS5K‐3 ENG⁺ and ENG^– cells in vivo were highly dependent on the microenvironment, with the renal microenvironment most preferable to ENG⁺ cells. In conclusion, the renal microenvironment, rather than the hypothesized ENG⁺ cell‐centered hierarchy, maintains cellular heterogeneity in clear cell renal cell carcinoma. Therefore, the effect of the microenvironment should be considered when evaluating the proliferative capability of renal cancer cells in the experimental settings.

Genome-wide analysis of DNA methylation identifies the apoptosis-related gene UQCRH as a tumor suppressor in renal cancer

DNA hypermethylation is frequently observed in clear cell renal cell carcinoma (ccRCC) and correlates with poor clinical outcomes. However, the detailed function of DNA hypermethylation in ccRCC has not been fully uncovered. Here, we show the role of DNA methylation in ccRCC progression through the identification of a target(s) of DNA methyltransferases (DNMT). Our preclinical model of ccRCC using the serial orthotopic inoculation model showed the upregulation of DNMT3B in advanced ccRCC. Pretreatment of advanced ccRCC cells with 5-aza-deoxycytidine, a DNMT inhibitor, attenuated the formation of primary tumors through the induction of apoptosis. DNA methylated sites were analyzed genome-wide using methylation array in reference to RNA-sequencing data. The gene encoding ubiquinol cytochrome c reductase hinge protein (UQCRH), one of the components of mitochondrial complex III, was extracted as a methylation target in advanced ccRCC. Immunohistochemical analysis revealed that the expression of UQCRH in human ccRCC tissues was lower than normal adjacent tissues. Silencing of UQCRH attenuated the cytochrome c release in response to apoptotic stimuli and resulted in enhancement of primary tumor formation in vivo, implying the tumor-suppressive role of UQCRH. Moreover, 5-aza-deoxycytidine enhanced the therapeutic efficiency of mammalian target of rapamycin inhibitor everolimus in vivo. These findings suggested that the DNMT3B-induced methylation of UQCRH may contribute to renal cancer progression and implicated clinical significance of DNMT inhibitor as a therapeutic option for ccRCC.

Biomarkers in Pancreatic Cancer as Analytic Targets for Nanomediated Imaging and Therapy

As the increase in therapeutic and imaging technologies is swiftly improving survival chances for cancer patients, pancreatic cancer (PC) still has a grim prognosis and a rising incidence. Practically everything distinguishing for this type of malignancy makes it challenging to treat: no approved method for early detection, extended asymptomatic state, limited treatment options, poor chemotherapy response and dense tumor stroma that impedes drug delivery. We provide a narrative review of our main findings in the field of nanoparticle directed treatment for PC, with a focus on biomarker targeted delivery. By reducing drug toxicity, increasing their tumor accumulation, ability to modulate tumor microenvironment and even improve imaging contrast, it seems that nanotechnology may one day give hope for better outcome in pancreatic cancer. Further conjugating nanoparticles with biomarkers that are overexpressed amplifies the benefits mentioned, with potential increase in survival and treatment response.

Whole-organ analysis of TGF-β-mediated remodelling of the tumour microenvironment by tissue clearing

Tissue clearing is one of the most powerful strategies for a comprehensive analysis of disease progression. Here, we established an integrated pipeline that combines tissue clearing, 3D imaging, and machine learning and applied to a mouse tumour model of experimental lung metastasis using human lung adenocarcinoma A549 cells. This pipeline provided the spatial information of the tumour microenvironment. We further explored the role of transforming growth factor-β (TGF-β) in cancer metastasis. TGF-β-stimulated cancer cells enhanced metastatic colonization of unstimulated-cancer cells in vivo when both cells were mixed. RNA-sequencing analysis showed that expression of the genes related to coagulation and inflammation were up-regulated in TGF-β-stimulated cancer cells. Further, whole-organ analysis revealed accumulation of platelets or macrophages with TGF-β-stimulated cancer cells, suggesting that TGF-β might promote remodelling of the tumour microenvironment, enhancing the colonization of cancer cells. Hence, our integrated pipeline for 3D profiling will help the understanding of the tumour microenvironment.

Establishment of bioluminescent imaging model using murine T cell lymphoma susceptive to NK cell-dependent immune-surveillance

Although the importance of NK cells as immune effector cells in controlling growth and metastatic dissemination of tumor cells has been widely recognized, it is unclear whether NK cells in different organs similarly control tumor cell growth and metastasis. In the present study, we established a bioluminescent imaging model of mouse T cell lymphoma cells, which are highly susceptive to NK cell-dependent immune-surveillance, to monitor the dissemination of lymphoma cells using an in vivo imaging system. The use of this model is expected to be a highly sensitive method to examine the role of NK cells in controlling lymphoma dissemination in a variety of tissues.

Cancer-associated fibroblasts-derived exosomal miR-3656 promotes the development and progression of esophageal squamous cell carcinoma via the ACAP2/PI3K-AKT signaling pathway

Esophageal squamous cell carcinoma (ESCC) is one of the most common gastrointestinal tumors, accounting for almost half a million deaths per year. Cancer-associated fibroblasts (CAFs) are the major constituent of the tumor microenvironment (TME) and dramatically impact ESCC progression. Recent evidence suggests that exosomes derived from CAFs are able to transmit regulating signals and promote ESCC development. In this study, we compared different the component ratios of miRNAs in exosomes secreted by CAFs in tumors and with those from normal fibroblasts (NFs) in precancerous tissues. The mRNA level of hsa-miR-3656 was significantly upregulated in the former exosomes. Subsequently, by comparing tumor cell development in vitro and in vivo, we found that the proliferation, migration and invasion capabilities of ESCC cells were significantly improved when miR-3656 was present. Further target gene analysis confirmed ACAP2 was a target gene regulated by miR-3656 and exhibited a negative regulatory effect on tumor proliferation. Additionally, the downregulation of ACAP2 triggered by exosomal-derived miR-3656 further promotes the activation of the PI3K/AKT and β-catenin signaling pathways and ultimately improves the growth of ESCC cells both in vitro and in xenograft models. These results may represent a potential therapeutic target for ESCC and provide a new basis for clinical treatment plans.

Neurotensin receptor 1 signaling promotes pancreatic cancer progression

Pancreatic cancer is one of the cancers with the poorest prognosis, with a 5-year survival rate of approximately 5-10%. Thus, it is urgent to identify molecular targets for the treatment of pancreatic cancer. Using serial transplantations in a mouse pancreatic orthotopic inoculation model, we previously produced highly malignant pancreatic cancer sublines with increased tumor-forming abilities in vivo. Here, we used these sublines to screen molecular targets for the treatment of pancreatic cancer. Among the genes with increased expression levels in the sublines, we focused on those encoding cell surface receptors that may be involved in the interactions between cancer cells and the tumor microenvironment. Based on our previous RNA-sequence analysis, we found increased expression levels of neurotensin (NTS) receptor 1 (NTSR1) in highly malignant pancreatic cancer sublines. Furthermore, re-analysis of clinical databases revealed that the expression level of NTSR1 was increased in advanced pancreatic cancer and that high NTSR1 levels were correlated with a poor prognosis. Overexpression of NTSR1 in human pancreatic cancer cells Panc-1 and SUIT-2 accelerated their tumorigenic and metastatic abilities in vivo. In addition, RNA-sequence analysis showed that MAPK and NF-κB signaling pathways were activated upon NTS stimulation in highly malignant cancer sublines and also revealed many new target genes for NTS in pancreatic cancer cells. NTS stimulation increased the expression of MMP-9 and other pro-inflammatory cytokines and chemokines in pancreatic cancer cells. Moreover, the treatment with SR48692, a selective NTSR1 antagonist, suppressed the activation of the MAPK and NF-κB signaling pathways and induction of target genes in pancreatic cancer cells in vitro, while the administration of SR48692 attenuated the tumorigenicity of pancreatic cancer cells in vivo. These findings suggest that NTSR1 may be a prognostic marker and a molecular target for pancreatic cancer treatment.

EMT-Induced Gemcitabine Resistance in Pancreatic Cancer Involves the Functional Loss of Equilibrative Nucleoside Transporter 1

Epithelial-mesenchymal transition (EMT) in cancer cells drives cancer chemoresistance, yet the molecular events of EMT that underpin the acquisition of chemoresistance are poorly understood. Here, we demonstrate a loss of gemcitabine chemosensitivity facilitated by human equilibrative nucleoside transporter 1 (ENT1) during EMT in pancreatic cancer and identify that cadherin switching from the epithelial (E) to neuronal (N) type, a hallmark of EMT, contributes to this loss. Our findings demonstrate that N-cadherin decreases ENT1 expression, membrane localization, and gemcitabine transport, while E-cadherin augments each of these. Besides E- and N-cadherin, another epithelial cell adhesion molecule, EpCAM, played a more prominent role in determining ENT1 membrane localization. Forced expression of EpCAM opposed cadherin switching with restored ENT1 expression, membrane localization, and gemcitabine transport in EMT-committed pancreatic cancer cells. In gemcitabine-treated mice, EpCAM-positive tumors had high ENT1 expression and reduced metastasis, whereas tumors with N-cadherin expression resisted gemcitabine treatment and formed extensive secondary metastatic nodules. Tissue microarray profiling and multiplexed IHC analysis of pancreatic cancer patient-derived primary tumors revealed EpCAM and ENT1 cell surface coexpression is favored, and ENT1 plasma membrane expression positively predicted median overall survival times in patients treated with adjuvant gemcitabine. Together, our findings identify ENT1 as an inadvertent target of EMT signaling mediated by cadherin switching and provide a mechanism by which mesenchymal pancreatic cancer cells evade gemcitabine therapy during EMT.

Molecular profile of pancreatic neuroendocrine neoplasms (PanNENs): Opportunities for personalized therapies

Pancreatic neuroendocrine neoplasms (panNENs) are the second most common epithelial tumors of the pancreas. Despite improvements in prognostic grading and staging systems, it remains a challenge to predict the clinical behavior of panNENs and the response to specific therapies given the high degree of heterogeneity of these tumors. Most panNENs are nonfunctional and present as advanced disease. However, systemic therapies provide modest benefits. Therefore, there is a need for predictive biomarkers to develop personalized treatment and to advance new drug development. The somatostatin receptors remain the only clinically established prognostic and predictive biomarkers in panNENs. Oncogenic drivers are at a very low frequency. Commonly mutated genes in panNENs include MEN1, chromatin remodeling genes (DAXX and ATRX), and mammalian target of rapamycin pathway genes. In contrast, poorly differentiated neuroendocrine carcinomas (panNECs), which carry a very poor prognosis, have distinctive mutations in certain genes (eg, RB1 and p53). Ongoing research to integrate epigenomics will provide tremendous opportunities to improve current understanding of the clinical heterogeneity of pancreatic neuroendocrine tumors and provide invaluable insight into the biology of these tumors, new drug development, and establishing personalized therapies.

CD137 agonist-based combination immunotherapy enhances activated, effector memory T cells and prolongs survival in pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma(PDAC) is resistant to the PD-1/PD-L1 blockade therapy. Previously, the combination of PD-1 blockade and vaccine therapy was shown to have a modest antitumor activity in murine models of PDAC. We used a murine syngeneic model of metastatic PDAC to identify, among multiple T cell modulators tested, which therapeutic agents in combination with the GVAX cancer vaccine and an anti-PD-1 antagonist antibody(αPD-1) are able to improve the survival. We found that an anti-CD137 agonist antibody(αCD137) most significantly improved survival in the mouse PDAC model. Moreover, αPD-1 and αCD137 together in combination with vaccine therapy more significantly increased the expression of costimulatory molecules CD137 and OX40 on CD4+PD-1+ and CD8+PD-1+ T cells comparing to αPD-1 or αCD137, respectively, suggesting that T cell activation within PDACs were enhanced by a synergy of αCD137 and αPD-1. On another hand, αCD137 treatment led to an increase in effector memory T cells independent of αPD-1. Although αCD137 does not increase the cytotoxic effector T cell function, the addition of αCD137 to GVAX+αPD-1 increased expression of IFNγ in EOMES + exhausted tumor-infiltrating T cells. Taken together, this preclinical study established the mechanism of targeting CD137 to enhance effector memory and activated T cells in PDAC. Immunohistochemistry analysis of resected human PDACs following the neo-adjuvant GVAX treatment showed increased levels of CD8⁺ T cells in those with high levels of CD137 expression, supporting an ongoing clinical trial of testing CD137 as a potential target in treating PDACs that are inflamed with T cells by vaccine therapy.

The synergistic tumor growth-inhibitory effect of probiotic Lactobacillus on transgenic mouse model of pancreatic cancer treated with gemcitabine

Pancreatic cancer is one of the most lethal and chemo-resistant cancers worldwide. Growing evidence supports the theory that the gut microbiota plays an essential role in modulating the host response to anti-cancer therapy. The present study aimed to explore the effect of probiotics as an adjuvant during chemotherapy for pancreatic cancer. An LSL-Kras^G12D/−-Pdx-1-Cre mouse model of pancreatic ductal adenocarcinoma (PDAC) was created to study the effects of using four-week multi-strain probiotics (Lactobacillus paracasei GMNL-133 and Lactobacillus reuteri GMNL-89) as an adjuvant therapy for controlling cancer progression. At 12 weeks of age, pancreatitis was induced in the mice by two intraperitoneal injection with caerulein (25 μg/kg 2 days apart). Over the next 4 weeks the mice were treated with intraperitoneal injections of gemcitabine in combination with the oral administration of probiotics. The pancreas was then harvested for analysis. Following caerulein treatment, the pancreases of the LSL-Kras^G12D/−-Pdx-1-Cre transgenic mice exhibited more extensive pancreatic intraepithelial neoplasia (PanIN) formation. Combined treatment with gemcitabine and probiotics revealed a lower grade of PanIN formation and a decrease in the expression of vimentin and Ki-67. Mice that received gemcitabine in combination with probiotics had lower aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. Notably, the use of high-dose probiotics alone without gemcitabine also had an inhibitory effect on PanIN changes and serum liver enzyme elevation. These findings suggest that probiotics are able to make standard chemotherapy more effective and could help improve the patient’s tolerance of chemotherapy.

ZEB1 and oncogenic Ras constitute a regulatory switch for stimulus-dependent E-cadherin downregulation

E-cadherin, an epithelial cell-specific cell adhesion molecule, has both promoting and suppressing effects on tumor invasion and metastasis. It is often downregulated during cancer progression through gene deletion/mutation, transcriptional repression, or epigenetic silencing. We describe a novel regulatory switch to induce stimulus-dependent downregulation of mRNA encoding E-cadherin (CDH1 mRNA) in KRAS-mutated cancer cells. The regulatory switch consists of ZEB1 and oncogenic K-Ras, does not target the promoter region of CDH1, and requires an external cue to temporally downregulate E-cadherin expression. Its repressive effect is maintained as long as the external stimulus continues and is attenuated with cessation of the stimulus. Contextual external cues that turn this regulatory switch on include activation of protein kinase C or fibroblast growth factor signaling. The mode of action is distinct from that of EPCAM repression by ZEB1, which does not require an external cue. Thus, KRAS-mutated cancer cells acquire a novel mode of regulating E-cadherin expression depending on ZEB1, which could contribute to phenotypic plasticity of cancer cells during malignant progression.

Intraductal Transplantation Models of Human Pancreatic Ductal Adenocarcinoma Reveal Progressive Transition of Molecular Subtypes

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal common malignancy, with little improvement in patient outcomes over the past decades. Recently, subtypes of pancreatic cancer with different prognoses have been elaborated; however, the inability to model these subtypes has precluded mechanistic investigation of their origins. Here, we present a xenotransplantation model of PDAC in which neoplasms originate from patient-derived organoids injected directly into murine pancreatic ducts. Our model enables distinction of the two main PDAC subtypes: intraepithelial neoplasms from this model progress in an indolent or invasive manner representing the classical or basal-like subtypes of PDAC, respectively. Parameters that influence PDAC subtype specification in this intraductal model include cell plasticity and hyperactivation of the RAS pathway. Finally, through intratumoral dissection and the direct manipulation of RAS gene dosage, we identify a suite of RAS-regulated secreted and membrane-bound proteins that may represent potential candidates for therapeutic intervention in patients with PDAC. SIGNIFICANCE: Accurate modeling of the molecular subtypes of pancreatic cancer is crucial to facilitate the generation of effective therapies. We report the development of an intraductal organoid transplantation model of pancreatic cancer that models the progressive switching of subtypes, and identify stochastic and RAS-driven mechanisms that determine subtype specification.See related commentary by Pickering and Morton, p. 1448.This article is highlighted in the In This Issue feature, p. 1426.

The involvement of exosomes in the diagnosis and treatment of pancreatic cancer

At the moment, pancreatic cancer is among the deadliest gastrointestinal diseases, and pancreatic cancer growth is a complex biological process that is based on different kinds of genes. Exosomes are extracellular vesicles containing microRNAs (miRNAs), messenger RNA (mRNA), and proteins, they act as the most prominent mediator of intercellular communication, and they regulate, instruct, and re-educate their surrounding microenvironment and target specific organs. Due to accumulative evidence proved that exosomes are involved in metastasis, cell proliferation, EMT, angiogenesis, and TME of pancreatic cancer, exosomes are crucial potential candidates to detect pancreatic cancer early. This review aims to convey the current understanding of the main functions employed by exosomes in early diagnosis and treatment of pancreatic cancer.

A 15-Gene Immune, Stromal, and Proliferation Gene Signature that Significantly Associates with Poor Survival in Patients with Pancreatic Ductal Adenocarcinoma

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease with dismal survival rates. Tumor microenvironment (TME), comprising of immune cells and cancer-associated fibroblasts, plays a key role in driving poor prognosis and resistance to chemotherapy. Herein, we aimed to identify a TME-associated, risk-stratification gene biomarker signature in PDAC.

EXPERIMENTAL DESIGN

The initial biomarker discovery was performed in The Cancer Genome Atlas (TCGA, n = 163) transcriptomic data. This was followed by independent validation of the gene signature in the International Cancer Genome Consortium (ICGC, n = 95), E-MTAB-6134 (n = 288), and GSE71729 (n = 123) datasets for predicting overall survival (OS), and for its ability to detect poor molecular subtypes. Clinical validation and nomogram establishment was undertaken by performing multivariate Cox regression analysis.

RESULTS

Our biomarker discovery effort identified a 15-gene immune, stromal, and proliferation (ISP) gene signature that significantly associated with poor OS [HR, 3.90; 95% confidence interval (CI), 2.36-6.41; P < 0.0001]. This signature also robustly predicted survival in three independent validation cohorts ICGC [HR, 2.63 (1.56-4.41); P < 0.0001], E-MTAB-6134 [HR, 1.53 (1.14-2.04); P = 0.004], and GSE71729 [HR, 2.33 (1.49-3.63); P < 0.0001]. Interestingly, the ISP signature also permitted identification of poor molecular PDAC subtypes with excellent accuracy in all four cohorts; TCGA (AUC = 0.94), ICGC (AUC = 0.91), E-MTAB-6134 (AUC = 0.80), and GSE71729 (AUC = 0.83). The ISP-derived high-risk patients exhibited significantly poor OS in a clinical validation cohort [n = 119; HR, 2.62 (1.50-4.56); P = 0.0004]. A nomogram was established which included the ISP, CA19-9, and T- and N-stage for eventual clinical translation.

CONCLUSIONS

We report a novel gene signature for risk-stratification and robust identification of patients with PDAC with poor molecular subtypes.

Implications of HIF-1α in the tumorigenesis and progression of pancreatic cancer

Pancreatic cancer is one of the leading causes of cancer-related deaths worldwide and is characterized by highly hypoxic tumor microenvironment. Hypoxia-inducible factor-1 alpha (HIF-1α) is a major regulator of cellular response to changes in oxygen concentration, supporting the adaptation of tumor cells to hypoxia in an oxygen-deficient tumor microenvironment. Numerous studies revealed the central role of HIF-1α in the carcinogenesis and progression of pancreatic cancer. This article reviewed the molecular mechanisms of how HIF-1α regulated tumorigenesis and progression of pancreatic cancer and suggested that targeting HIF-1α and its signaling pathways could be promising therapeutics for pancreatic cancer.

Organoid-based ex vivo reconstitution of Kras-driven pancreatic ductal carcinogenesis

The organoid culture technique has been recently applied to modeling carcinogenesis in several organs. To further explore its potential and gain novel insights into tumorigenesis, we here investigated whether pancreatic ductal adenocarcinoma (PDA) could be generated as subcutaneous tumors in immunocompromised nude mice, by genetic engineering of normal organoids. As expected, acute induction of KrasG12Din vitro occasionally led to development of tiny nodules compatible with early lesions known as pancreatic intraepithelial neoplasia (PanIN). KrasG12D-expressing cells were enriched after inoculation in the subcutis, yet proved rather declined during culture, suggesting that its advantage might depend on surrounding environments. Depletion of growth factors or concurrent Trp53 deletion resulted in its robust enrichment, invariably leading to development of PanIN or large high-grade adenocarcinoma, respectively, consistent with in vivo mouse studies for the same genotype. Progression from PanIN was also recapitulated by subsequent knockdown of common tumor suppressors, whereas the impact of Tgfbr2 deletion was only partially recapitulated, illustrating genotype-dependent requirement of the pancreatic niche for tumorigenesis. Intriguingly, analysis of tumor-derived organoids revealed that KrasG12D-expressing cells with spontaneous deletion of wild-type Kras were positively selected and exhibited an aging-related mutation signature in nude mice, mirroring the pathogenesis of human PDA, and that the sphere-forming potential and orthotopic tumorigenicity in syngenic mice were significantly augmented. These observations highlighted the relevance of the subcutis of nude mice in promoting PDA development despite its ectopic nature. Taken together, pancreatic carcinogenesis could be considerably recapitulated with organoids, which would probably serve as a novel disease model.

Cancer cell-derived interleukin-33 decoy receptor sST2 enhances orthotopic tumor growth in a murine pancreatic cancer model

Background

Proinflammatory interleukin-33 (IL-33) binds to its receptor ST2L and is involved in inflammation and the malignant behavior of cancer cells. However, the role of IL-33-ST2L and the IL-33 decoy receptor sST2 in the tumor microenvironment of pancreatic cancer is unclear. Because we previously reported that sST2 derived from colon cancer cells profoundly influences malignant tumor growth, we hypothesized that sST2 released from pancreatic cancer cells also modulates IL-33-ST2L signaling in the tumor microenvironment, thereby influencing tumor growth.

Methods

ST2 (ST2L and sST2) expression in mouse pancreatic cancer Panc02 cells was downregulated by shRNAs. mRNA expression levels of IL-33, ST2, cytokines and chemokines in the cells and tumor tissues were examined using real-time PCR. sST2 secretion and the amount of CXCL3 in tumor tissues were measured using ELISA. Tumor growth was investigated after injection of the cells into the pancreas of C57BL/6 mice. MPO⁺, F4/80⁺ and CD20⁺ cells in tumor tissues were detected using immunohistochemistry.

Results

Some but not all human and mouse pancreatic cancer cell lines preferentially expressed sST2. Then, we investigated the role of sST2 in orthotopic tumor growth of sST2-expressing mouse pancreatic cancer Panc02 cells in immunocompetent mice. shRNA-mediated knockdown of sST2 expression in the cells suppressed orthotopic tumor growth, which was partially recovered by overexpression of shRNA-resistant sST2 mRNA but was not evident in IL-33 knockout mice. This was associated with decreases in Cxcl3 expression, vessel density and accumulation of cancer-associated neutrophils but not cancer-associated macrophages. Administration of SB225002, an inhibitor of the CXCL3 receptor CXCR2, induced similar effects.

Conclusions

Cancer cell-derived sST2 enhances tumor growth through upregulation of CXCL3 via inhibition of IL-33-ST2L signaling in the tumor microenvironment of pancreatic cancer. These results suggest that the sST2 and the CXCL3-CXCR2 axis could be therapeutic targets.

NGF from pancreatic stellate cells induces pancreatic cancer proliferation and invasion by PI3K/AKT/GSK signal pathway

Pancreatic cancer (PC) is a continuously high lethal disease, and the tumour microenvironment plays a pivotal role during PC progression. Herein, we focus on that the Nerve growth factor (NGF)/Tropomyosin-related kinase A (TrkA), in pancreatic stellate cells-pancreatic cancer cells (PSCs-PC cells) co-culture system, influences PC proliferation and invasion. The model of PC cells and PSCs was directly co-cultured in a no-touch manner, using the Transwell as the co-culture system. NGF and TrkA expression was measured in cultured system by real-time PCR, immunofluorescence, Western blotting analysis or ELISA. Small interfering RNA transfection was used to regulate the expression of TrkA in PC cells. The promotion of cancer invasion was investigated using Matrigel Transwell assay. In our study, NGF/TrkA is overexpressed in PSCs-PC cells co-culture system and promotes the invasion and proliferation of PC cells. And the epithelial-mesenchymal transition-related genes are influenced by si-TrkA. What's more, NGF/TrkA regulates the PC cell proliferation and invasion via activation of PI3K/AKT/GSK signalling. The present study demonstrated NGF/TrkA promoted the PC cell proliferation and invasion in the co-culture system by the activation of the PI3K/AKT/GSK signal cascade, providing a potential therapeutic target for PC patients.

Epigenetic remodelling shapes inflammatory renal cancer and neutrophil-dependent metastasis

Advanced clear cell renal cell carcinoma (ccRCC) frequently causes systemic inflammation. Recent studies have shown that cancer cells reshape the immune landscape by secreting cytokines or chemokines. This phenotype, called cancer-cell-intrinsic inflammation, triggers a metastatic cascade. Here, we identified the functional role and regulatory mechanism of inflammation driven by advanced ccRCC cells. The inflammatory nature of advanced ccRCC was recapitulated in a preclinical model of ccRCC. Amplification of cancer-cell-intrinsic inflammation during ccRCC progression triggered neutrophil-dependent lung metastasis. Massive expression of inflammation-related genes was transcriptionally activated by epigenetic remodelling through mechanisms such as DNA demethylation and super-enhancer formation. A bromodomain and extra-terminal motif inhibitor synchronously suppressed C-X-C-type chemokines in ccRCC cells and decreased neutrophil-dependent lung metastasis. Overall, our findings provide insight into the nature of inflammatory ccRCC, which triggers metastatic cascades, and suggest a potential therapeutic strategy.

Resveratrol Ameliorates the Malignant Progression of Pancreatic Cancer by Inhibiting Hypoxia-induced Pancreatic Stellate Cell Activation

Pancreatic cancer is characterized by a hypoxic tumor microenvironment, which is primarily caused by massive fibrosis with pancreatic stellate cells (PSCs) as a main component. Our previous studies have shown that resveratrol can significantly inhibit pancreatic cancer. However, whether resveratrol can inhibit hypoxia-induced cancer development remains unclear. The objective of this study was to explore whether PSCs and hypoxia synergistically mediate aggressiveness in pancreatic cancer and detect the potential pleiotropic protective effects of resveratrol on hypoxia-induced pancreatic cancer progression. Human PSCs were treated with vehicle or resveratrol under normoxic or hypoxic conditions (3% O2), and PSC activation was assessed by immunofluorescence staining. SiRNA was used to silence hypoxia-inducible factor 1 (HIF-1) expression. The invasive capacity of Panc-1 and Mia Paca-2 cells cocultured with conditioned medium from PSCs was assessed by Transwell assays. To examine tumor formation kinetics, KPC (LSL-KrasG12D/+, Trp53fl/+, and Pdx1-Cre) mice were sacrificed at different time points. To investigate the antitumor effects of resveratrol in vivo, 8-wk-old KPC mice were divided into two groups and treated daily with or without 50 mg/kg resveratrol. Our data indicate that hypoxia induces PSC activation via HIF-1 and that the interleukin 6, vascular endothelial growth factor A, and stromal cell-derived factor 1 derived from activated PSCs promote both invasion and the epithelial-mesenchymal transition and inhibit apoptosis in pancreatic cancer cells. However, resveratrol inhibits hypoxia-induced PSC activation, blocks the interplay between PSCs and pancreatic cancer cells, and suppresses the malignant progression of pancreatic cancer and stromal desmoplasia in a KPC mouse model. Our data highlight that activated PSCs and intratumoral hypoxia are essential targets for novel strategies to prevent tumor-microenvironment interactions. Furthermore, the polyphenolic compound resveratrol effectively ameliorates the malignant progression of pancreatic ductal adenocarcinoma.

Dendritic cells in pancreatic cancer immunotherapy: Vaccines and combination immunotherapies

Despite significant advances over the past decades of research, pancreatic cancer (PC) continues to have the worst 5-year survival of any malignancy. Dendritic cells (DCs) are the most potent professional antigen-presenting cells and are involved in the induction and regulation of antitumor immune responses. DC-based immunotherapy has been used in clinical trials for PC. Although safety, efficacy, and immune activation were reported in patients with PC, DC vaccines have not yet fulfilled their promise. Additional strategies for combinatorial approaches aimed to augment and sustain the antitumor specific immune response elicited by DC vaccines are currently being investigated. Here, we will discuss DC vaccination immunotherapies that are currently under preclinical and clinical investigation and potential combination approaches for treating and improving the survival of PC patients.

[Isolation of cancer stem cells and the establishment of a H 2O 2-resistant cancer stem cell model]

Objective

To isolate cancer stem cells (CST) from human breast cancer cell line (MCF-7) and study their sensitivity toward oxidative stress.

Methods

MCF-7 cells were cultured in serum-free suspension culture medium to identify cells forming the sphere phenotype. The morphological changes of MCF-7 cells were observed by inverted phase contrast microscope (compared with MCF-7 cells cultured in serum-free suspension culture medium). The expression of CST marker CD133 was detected by immunocytochemical staining in CST cell spheres (experimental group) with a diameter of 100 μm and MCF-7 cells (control group) with a fusion degree of 70%. The positive rate of CD133 was detected by flow cytometry in the third generation of tumor cells with diameter of 150 μm. The second generation of tumor globular cells (experimental group) with diameter of 150 μm and corresponding MCF-7 cells (control group) were taken to be damaged by 50 mol/L H ₂O ₂ for 120 minutes. The expression of DNA damage marker histone H2AX phosphorylation (γH2AX) was detected by immunocytochemical staining.

Results

Inverted phase contrast microscopy showed that MCF-7 cells grew initially in a single-cell adherent state, then aggregated and grew in serum-free suspension culture medium, and finally formed CST cell spheres, while the control MCF-7 cells cultured in MCF-7 cell culture medium grew extensively and could not grow in suspension. Fluorescence microscopy showed that the expression of CD133 in MCF-7 cells of control group was negative, while that in experimental group was positive. Flow cytometry showed that CD133 was positive in CST cells, and the positive rate was 92%. Inverted fluorescence microscopy showed that the expression of γH2AX in CST tumor spheres of experimental group was significantly lower than that in MCF-7 cells of control group after 120 minutes of H ₂O ₂ injury.

Conclusion

Serum-free suspension culture medium can produce globular CST cells from MCF-7 tumor cell line, which have strong antioxidant damage.

Xenografts Derived From Patients' Ascites Recapitulate the Gemcitabine Resistance Observed in Pancreatic Cancer Patients

OBJECTIVES

Most patient-derived pancreatic ductal adenocarcinoma (PDAC) xenografts have been established from surgical specimens of patients who have not received chemotherapy. However, xenografts have rarely been established from chemotherapy-resistant, advanced PDACs, because such cases are usually inoperable. The purpose of this study is to establish patient-derived xenografts using PDAC cells refractory to chemotherapy.

METHODS

Clinical PDAC cells obtained from ascites of patients who had received continuous chemotherapy were implanted into the flanks of immunocompromised mice. Growth and histological features of the xenografts with and without gemcitabine treatment were then analyzed.

RESULTS

Ascites-derived PDAC cells were successfully expanded through serial xenograft passage without changes in histological appearance. While treatment with gemcitabine substantially inhibited the growth of all PDAC xenografts tested, the tumor volume gradually increased, and the tumors showed marked regrowth even under continued gemcitabine treatment. These findings are consistent with the actual clinical course of the corresponding patients for each xenograft.

CONCLUSIONS

Ascites-derived xenograft models represent a valuable experimental system for testing the efficacy of currently available therapeutic compounds on chemotherapy-resistant PDAC cells and for elucidation of the mechanisms underlying chemotherapy resistance.

The Sustained Induction of c-MYC Drives Nab-Paclitaxel Resistance in Primary Pancreatic Ductal Carcinoma Cells

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with limited and, very often, ineffective medical and surgical therapeutic options. The treatment of patients with advanced unresectable PDAC is restricted to systemic chemotherapy, a therapeutic intervention to which most eventually develop resistance. Recently, nab-paclitaxel (n-PTX) has been added to the arsenal of first-line therapies, and the combination of gemcitabine and n-PTX has modestly prolonged median overall survival. However, patients almost invariably succumb to the disease, and little is known about the mechanisms underlying n-PTX resistance. Using the conditionally reprogrammed (CR) cell approach, we established and verified continuously growing cell cultures from treatment-naïve patients with PDAC. To study the mechanisms of primary drug resistance, nab-paclitaxel-resistant (n-PTX-R) cells were generated from primary cultures and drug resistance was verified in vivo, both in zebrafish and in athymic nude mouse xenograft models. Molecular analyses identified the sustained induction of c-MYC in the n-PTX-R cells. Depletion of c-MYC restored n-PTX sensitivity, as did treatment with either the MEK inhibitor, trametinib, or a small-molecule activator of protein phosphatase 2a. IMPLICATIONS: The strategies we have devised, including the patient-derived primary cells and the unique, drug-resistant isogenic cells, are rapid and easily applied in vitro and in vivo platforms to better understand the mechanisms of drug resistance and for defining effective therapeutic options on a patient by patient basis.

Axon Guidance Molecules Promote Perineural Invasion and Metastasis of Orthotopic Pancreatic Tumors in Mice

BACKGROUND & AIMS

Little is known about mechanisms of perineural invasion (PNI) by pancreatic ductal adenocarcinomas (PDAs) or other tumors. Annexin A2 (ANXA2) regulates secretion of SEMA3D, an axon guidance molecule, which binds and activates the receptor PLXND1 to promote PDA invasion and metastasis. We investigated whether axon guidance molecules promote PNI and metastasis by PDA cells in mice.

METHODS

We performed studies in a dorsal root ganglion (DRG) invasion system, wild-type C57BL/6 mice (controls), mice with peripheral sensory neuron-specific disruption of PlxnD1 (PLAC mice), LSL-KRASG12D/+;LSL-TP53R172H/+;PDX-1-CRE+/+ (KPC) mice, and KPC mice crossed with ANXA2-knockout mice (KPCA mice). PDA cells were isolated from KPC mice and DRG cells were isolated from control mice. Levels of SEMA3D or ANXA2 were knocked down in PDA cells with small hairpin and interfering RNAs and cells were analyzed by immunoblots in migration assays, with DRGs and with or without antibodies against PLXND1. PDA cells were injected into the pancreas of control and PLAC mice, growth of tumors was assessed, and tumor samples were analyzed by histology. DRG cells were incubated with SEMA3D and analyzed by live imaging. We measured levels of SEMA3D and PLXND1 in PDA specimens from patients with PNI and calculated distances between tumor cells and nerves.

RESULTS

DRG cells increase the migration of PDC cells in invasion assays; knockdown of SEMA3D in PDA cells or antibody blockade of PLXND1 on DRG cells reduced this invasive activity. In mice, orthotopic tumors grown from PDA cells with knockdown of SEMA3D, and in PLAC mice, orthotopic tumors grown from PDA cells, had reduced innervation and formed fewer metastases than orthotopic tumors grown from PDA cells in control mice. Increased levels of SEMA3D and PLXND1 in human PDA specimens associated with PNI.

CONCLUSIONS

DRG cells increase the migratory and invasive activities of pancreatic cancer cells, via secretion of SEMA3D by pancreatic cells and activation of PLXND1 on DRGs. Knockdown of SEMA3D and loss of neural PLXND1 reduces innervation of orthotopic PDAs and metastasis in mice. Increased levels of SEMA3D and PLXND1 in human PDA specimens associated with PNI. Strategies to disrupt the axon guidance pathway mediated by SEMA3D and PLXND1 might be developed to slow progression of PDA.

Lactoferrin deficiency induces a pro-metastatic tumor microenvironment through recruiting myeloid-derived suppressor cells in mice

Lactoferrin, an innate immunity molecule, is involved in anti-inflammatory, anti-microbial, and anti-tumor activities. We previously reported that lactoferrin is downregulated in specimens of nasopharyngeal carcinoma and negatively associated with tumor progression and metastasis of patients with nasopharyngeal carcinoma. However, the relationship between lactoferrin and the pro-metastatic microenvironment has not been reported yet. Here, by using the lactoferrin knockout mouse, we found that lactoferrin deficiency facilitated melanoma cells metastasizing to lungs, through recruiting myeloid-derived suppressor cells (MDSCs) in the lungs. Mechanistic studies showed that in the lung microenvironment of the lactoferrin knockout mice, the TLR9 signaling was the most repressed signaling. Lactoferrin can induce MDSCs differentiation and apoptosis, as well as upregulate TLR9 expression. TLR9 agonist or lactoferrin treatment can rescue this phenotype in the tumor metastasis mouse model. Our results suggest a protective role of lactoferrin in cancer metastasis, along with a deficiency in certain components of the innate immune system, may lead to a pro-metastatic tumor microenvironment.

High glucose promotes pancreatic cancer cells to escape from immune surveillance via AMPK-Bmi1-GATA2-MICA/B pathway

Background

Modulation of cell surface expression of MHC class I chain-related protein A/B (MICA/B) has been proven to be one of the mechanisms by which tumor cells escape from NK cell-mediated killing. Abnormal metabolic condition, such as high glucose, may create a cellular stress milieu to induce immune dysfunction. Hyperglycemia is frequently presented in the majority of pancreatic cancer patients and is associated with poor prognosis. In this study, we aimed to detect the effects of high glucose on NK cell-mediated killing on pancreatic cancer cells through reduction of MICA/B expression.

Methods

The lysis of NK cells on pancreatic cancer cells were compared at different glucose concentrations through lactate dehydrogenase release assay. Then, qPCR, Western Blot, Flow cytometry and Immunofluorescence were used to identify the effect of high glucose on expression of MICA/B, Bmi1, GATA2, phosphorylated AMPK to explore the underlying mechanisms in the process. Moreover, an animal model with diabetes mellitus was established to explore the role of high glucose on NK cell-mediated cytotoxicity on pancreatic cancer in vivo.

Results

In our study, high glucose protects pancreatic cancer from NK cell-mediated killing through suppressing MICA/B expression. Bmi1, a polycomb group (PcG) protein, was found to be up-regulated by high glucose, and mediated the inhibition of MICA/B expression through promoting GATA2 in pancreatic cancer. Moreover, high glucose inhibited AMP-activated protein kinase signaling, leading to high expression of Bmi1.

Conclusion

Our findings identify that high glucose may promote the immune escape of pancreatic cancer cells under hyperglycemic tumor microenvironment. In this process, constitutive activation of AMPK-Bmi1-GATA2 axis could mediate MICA/B inhibition, which may serve as a therapeutic target for further intervention of pancreatic cancer immune evasion.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1209-9) contains supplementary material, which is available to authorized users.

c-Ski accelerates renal cancer progression by attenuating transforming growth factor β signaling

Although transforming growth factor beta (TGF‐β) is known to be involved in the pathogenesis and progression of many cancers, its role in renal cancer has not been fully investigated. In the present study, we examined the role of TGF‐β in clear cell renal carcinoma (ccRCC) progression in vitro and in vivo. First, expression levels of TGF‐β signaling pathway components were examined. Microarray and immunohistochemical analyses showed that the expression of c‐Ski, a transcriptional corepressor of Smad‐dependent TGF‐β and bone morphogenetic protein (BMP) signaling, was higher in ccRCC tissues than in normal renal tissues. Next, a functional analysis of c‐Ski effects was carried out. Bioluminescence imaging of renal orthotopic tumor models demonstrated that overexpression of c‐Ski in human ccRCC cells promoted in vivo tumor formation. Enhancement of tumor formation was also reproduced by the introduction of a dominant‐negative mutant TGF‐β type II receptor into ccRCC cells. In contrast, introduction of the BMP signaling inhibitor Noggin failed to accelerate tumor formation, suggesting that the tumor‐promoting effect of c‐Ski depends on the inhibition of TGF‐β signaling rather than of BMP signaling. Finally, the molecular mechanism of the tumor‐suppressive role of TGF‐β was assessed. Although TGF‐β signaling did not affect tumor angiogenesis, apoptosis of ccRCC cells was induced by TGF‐β. Taken together, these findings suggest that c‐Ski suppresses TGF‐β signaling in ccRCC cells, which, in turn, attenuates the tumor‐suppressive effect of TGF‐β.

Transforming growth factor-β in pancreatic diseases: Mechanisms and therapeutic potential

Pancreatic diseases, such as acute pancreatitis, chronic pancreatitis, and pancreatic cancer, are common gastrointestinal diseases resulting in the development of local and systemic complications with a high risk of death. Numerous studies have examined pancreatic diseases over the past few decades; however, the pathogenesis remains unclear, and there is a lack of effective treatment options. Recently, emerging evidence has suggested that transforming growth factor beta (TGF-β) exerts controversial functions in apoptosis, inflammatory responses, and carcinogenesis, indicating its complex role in the pathogenesis of pancreas-associated disease. Therefore, a further understanding of relevant TGF-β signalling will provide new ideas and potential therapeutic targets for preventing disease progression. This is the first systematic review of recent data from animal and human clinical studies focusing on TGF-β signalling in pancreas damage and diseases. This information may aid in the development of therapeutic agents for regulating TGF-β in this pathology to prevent or treat pancreatic diseases.