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Summary: Background: Previously, we uncovered a patient subgroup with highly malignant pancreatic cancer with serum markers CEA+/CA125+/CA19-9 ≥ 1000 U/mL (triple-positive, TP). However, the underlying immunosuppressive mechanism in the tumor immune microenvironment (TIME) of this subgroup is still unknown. Methods: Human tissues were analyzed by flow cytometry, mass cytometry, and immunofluorescence staining. Mouse pancreatic ILC2s were expanded in vivo and used for RNA sequencing, chromatin immunoprecipitation (ChIP), and chemotaxis assays. Findings: Through microarray data, we identified the accumulation of the hypoxia-induced factor-1α (HIF-1α) pathway in these TP patients. Via flow and mass cytometry, we discovered that a special subset of ILC2s were highly infiltrated in TP patients. Under the hypoxia microenvironment, ILC2s were found undergo a transition to a IL10+ regulatory phenotype, we named ILCregs which was correlated with pancreatic ductal adenocarcinoma (PDAC) progression. Further, neoadjuvant chemotherapy could ameliorate hypoxic tumor microenvironments so that significantly reverse the regulatory phenotype of ILCregs. Moreover, most tumor ILC2 were CD103−, which indicated its circulatory origin. The expression of Ccr2 was significantly upregulated on mouse ILCregs, and these cells selectively migrated to CCL2. Interpretation: Our results indicate that the hypoxia microenvironment creates an immunosuppressive TIME by inducing ILCregs from a population of circulating group 2 ILCs in TP PDAC patients. Funding: This study was jointly supported by the National Natural Science Foundation of China (U21A20374, 82173091, and 81701630)

BackgroundThe four major pathways in gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) including chromatin remodeling, DNA damage repair, activation of mTOR signaling, and telomere maintenance were mediated by some critical molecules and constituted critical processes of regulation in cancer-causing processes. However, the interplay and potential role of these pathway-related molecules in the tumor microenvironment of the primary and metastatic site remained unknown.MethodsWe systematically evaluated the mRNA expression of 34 molecules associated with the four pathways in 227 GEP−NEN samples from 5 datasets. We assigned the samples into two expression patterns of pathway-related molecules by an unsupervised clustering method. Subsequently, we explored the specific cell-related molecules, especially immune and stromal cells using the WGCNA method, based on differentially expressed genes (DEGs) responsible for the different patterns of pathway-related molecules, which provided a new method to qualify the pathway-related subtypes of individual tumors, then the PC_Score and PI_Score scoring systems were also constructed using obtained specific cell-related molecules. Furthermore, we performed the association of pathway-related subtypes with characteristics of immune landscape in primary and metastatic GEP-NENs.ResultsWe demonstrated that the specific pathway-related molecules (SMARCA4, MLH1, TSC1, ATRX, and ATR) were associated with cytolytic activity. Then we identified the two distinct patterns of pathway-related molecules, which were characteristic with a significantly distinct immune landscape. Using WGCNA, we also identified the fibroblast-related molecules, including ASPN, COL10A1, COL3A1, EDNRA, MYL9, PRELP, RAB31, SPARC, and THBS2, and immune-related molecules including CASP1, CCL5, CTSS, CYBRD1, PMP22, and TFEC. Based on these specific markers, we identified four distinct pathway-related subtypes, characterized by immune and fibrotic enriched (I/FE), immune enriched (IE), fibrotic enriched (FE), and immune and fibrotic desert (I/FD), of which I/FE was characteristic with the highest PC_Score and PI_Score whereas I/FD presents the opposite trend. I/FE was positively correlated with immune landscape of T-cell activation and immunosuppression. Furthermore, the I/FE marked GEP-NENs with increased immune activation scores (T-cell costimulation, MHC I presentation, and APC costimulation). Importantly, the four distinct pathway-related subtypes were not conserved in different tumor sites, because I/FE was lacking in the liver metastatic site even though IE, FE, and I/FD also could be observed in the metastatic site.ConclusionsThis study was the first to perform a comprehensive analysis of the four major pathways in GEP-NENs. We demonstrated the potential function of these pathway-related molecules in immune landscapes. Our findings indicated that the primary and metastatic GEP-NENs had distinct antitumor phenotypes. This work highlighted the interplay and potential clinical utility of these pathway-related molecules in GEP-NENs.

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant cancer with limited treatment options. Chimeric antigen receptor T cells (CAR‐T) are genetically engineered T cells that can specifically kill tumor cells without major histocompatibility complex restriction. Encouraging progress in CAR‐T therapy for PDAC has been made in preclinical and early phase clinical trials. Challenges in CAR‐T therapy for solid tumors still exist, including immunosuppressive microenvironment, interstitial barrier, poor chemotaxis, and the “on‐target, off‐tumor” effect. Applying neoantigens of PDAC as targets for CAR‐T therapy, recognizing the CAR‐T subgroup with better antitumor effect, and designing a CAR‐T system targeting stroma of PDAC may contribute to develop a powerful CAR‐T therapy for PDAC in the future.

Abstract Collagen is the major component of the tumor microenvironment and participates in cancer fibrosis. Collagen biosynthesis can be regulated by cancer cells through mutated genes, transcription factors, signaling pathways and receptors; furthermore, collagen can influence tumor cell behavior through integrins, discoidin domain receptors, tyrosine kinase receptors, and some signaling pathways. Exosomes and microRNAs are closely associated with collagen in cancer. Hypoxia, which is common in collagen-rich conditions, intensifies cancer progression, and other substances in the extracellular matrix, such as fibronectin, hyaluronic acid, laminin, and matrix metalloproteinases, interact with collagen to influence cancer cell activity. Macrophages, lymphocytes, and fibroblasts play a role with collagen in cancer immunity and progression. Microscopic changes in collagen content within cancer cells and matrix cells and in other molecules ultimately contribute to the mutual feedback loop that influences prognosis, recurrence, and resistance in cancer. Nanoparticles, nanoplatforms, and nanoenzymes exhibit the expected gratifying properties. The pathophysiological functions of collagen in diverse cancers illustrate the dual roles of collagen and provide promising therapeutic options that can be readily translated from bench to bedside. The emerging understanding of the structural properties and functions of collagen in cancer will guide the development of new strategies for anticancer therapy.

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a devastating malignancy with poor prognosis. Many preoperative biomarkers can predict postoperative survival of PDAC patients. In this study, we created a novel ratio index based on preoperative liver function test, γ‐glutamyltransferase‐to‐albumin ratio (GAR), and evaluated its prognostic value in predicting clinical outcomes of PDAC patients following radical surgery. We retrospectively enrolled 833 PDAC patients who had underwent radical surgery at our institution between January 2010 and January 2017. Patients were divided into two groups according to the cut‐off value of GAR. Univariate and multivariate survival analysis between the groups were evaluated. TNM stage, GAR, preoperative serum carbohydrate antigen 19‐9 (CA19‐9) and tumor differentiation were combined to generate a more accurate prognostic model. The optimal cut‐off value of GAR was 0.65. Significant correlations were found between GAR and tumor location, tumor size, vascular invasion, obstructive jaundice, biliary drainage and parameters of liver function test. Univariate and multivariate analysis showed that high level of GAR independently predicted poorer postoperative overall survival (OS, P < 0.001) and recurrence‐free survival (RFS, P < 0.001). Subgroup analysis demonstrated that GAR was predictive of survival in patients without biliary obstruction or severely impaired liver function. In addition, integration of GAR, preoperative serum CA19‐9, and tumor differentiation into TNM staging system could better stratify the prognosis for PDAC patients compared with TNM stage alone. Our study demonstrates that preoperative GAR is an independent prognostic factor for prediction of surgical outcomes in PDAC patients. Combination of TNM stage, GAR, preoperative serum CA19‐9, and tumor differentiation can enhance the prognostic accuracy.

Immunosuppression is an important factor for the poor prognosis of pancreatic ductal adenocarcinoma (PDAC). Follicular helper T cells (Tfh cells) play an anti-tumor role in various malignant solid tumors and predict better patient prognosis. In the present study, we aimed to determine the immunosuppressive mechanism associated with Tfh cells and explore a new strategy to improve the tumor microenvironment of PDAC. Flow cytometry was used to detect the infiltration and proportion of Tfh cells in tumor tissues and peripheral blood from patients with PDAC. The spatial correlations of Tfh cells with related immune cells were evaluated using immunofluorescence. The function of Tfh cells was examined using in vitro and in vivo model systems. The high infiltration of Tfh cells predicted better prognosis in patients with PDAC. Tfh cells recruited CD8+ T cells and B cells by secreting C-X-C motif chemokine ligand 13 (CXCL13), and promoted the maturation of B cells into antibody-producing plasma cells by secreting interleukin 21 (IL-21), thereby promoting the formation of an immunoactive tumor microenvironment. The function of Tfh cells was inhibited by the programmed cell death 1 ligand 1 (PD-L1)/programmed cell death 1 (PD-1) signaling pathway in PDAC, which could be reversed using neoadjuvant chemotherapy. Treatment with recombinant CXCL13, IL-21 and Tfh cells alleviated tumor growth and enhanced the infiltration of CD8+ T cells and B cells, as well as B cell maturation in a PDAC mouse model. Our results revealed the important role of Tfh cells in mediating anti-tumor cellular immunity and humoral immunity in PDAC via secreting CXCL13 and IL-21 and determined a novel mechanism of immunosuppression in PDAC.

The total weight of Extended-Range Electric Vehicle (E-REV) is too heavy, which affects rear-end collision safety. Using numerical simulation, a lightweight method is designed to reduce E-REV body and key parts weight based on rear-end collision failure analysis. To calculate and optimize the performance of vehicle safety, the simulation model of E-REV rear-end collision safety is built by using finite element analysis. Drive battery pack lightweight design method is analyzed and the bending mode and torsional mode of E-REV before and after lightweight are compared to evaluate E-REV rear-end collision safety performance. The simulation results of optimized E-REV safety structure are verified by both numerical simulation and experimental investigation of the entire vehicle crash test.