Mobilization of CD8+ T Cells via CXCR4 Blockade Facilitates PD-1 Checkpoint Therapy in Human Pancreatic Cancer

Emerging interleukin targets in the tumour microenvironment: implications for the treatment of gastrointestinal tumours

The effectiveness of antitumour immunity is dependent on intricate cytokine networks. Interleukins (ILs) are important mediators of complex interactions within the tumour microenvironment, including regulation of tumour-infiltrating lymphocyte proliferation, differentiation, migration and activation. Our evolving and increasingly nuanced understanding of the cell type-specific and heterogeneous effects of IL signalling has presented unique opportunities to fine-tune elaborate IL networks and engineer new targeted immunotherapeutics. In this review, we provide a primer for clinicians on the challenges and potential of IL-based treatment. We specifically detail the roles of IL-2, IL-10, IL-12 and IL-15 in shaping the tumour-immune landscape of gastrointestinal malignancies, paying particular attention to promising preclinical findings, early-stage clinical research and innovative therapeutic approaches that may properly place ILs to the forefront of immunotherapy regimens.

Immunotherapy and Pancreatic Cancer: A Lost Challenge?

Although immunotherapy has proved to be a very efficient therapeutic strategy for many types of tumors, the results for pancreatic cancer (PC) have been very poor. Indeed, chemotherapy remains the standard treatment for this tumor in the advanced stage. Clinical data showed that only a small portion of PC patients with high microsatellite instability/mismatch repair deficiency benefit from immunotherapy. However, the low prevalence of these alterations was not sufficient to lead to a practice change in the treatment strategy of this tumor. The main reasons for the poor efficacy of immunotherapy probably lie in the peculiar features of the pancreatic tumor microenvironment in comparison with other malignancies. In addition, the biomarkers usually evaluated to define immunotherapy efficacy in other cancers appear to be useless in PC. This review aims to describe the main features of the pancreatic tumor microenvironment from an immunological point of view and to summarize the current data on immunotherapy efficacy and immune biomarkers in PC.

Organotypic Models for Functional Drug Testing of Human Cancers

In the era of personalized oncology, there have been accelerated efforts to develop clinically relevant platforms to test drug sensitivities of individual cancers. An ideal assay will serve as a diagnostic companion to inform the oncologist of the various treatments that are sensitive and insensitive, thus improving outcome while minimizing unnecessary toxicities and costs. To date, no such platform exists for clinical use, but promising approaches are on the horizon that take advantage of improved techniques in creating human cancer models that encompass the entire tumor microenvironment, alongside technologies for assessing and analyzing tumor response. This review summarizes a number of current strategies that make use of intact human cancer tissues as organotypic cultures in drug sensitivity testing.

Anti-PD-1 therapy achieves favorable outcomes in HBV-positive non-liver cancer

Anti-PD-1 therapy has shown promising outcomes in the treatment of different types of cancer. It is of fundamental interest to analyze the efficacy of anti-PD-1 therapy in cancer patients infected with hepatitis B virus (HBV) since the comorbidity of HBV and cancer is widely documented. We designed a multicenter retrospective study to evaluate the efficacy of anti-PD-1 therapy on non-liver cancer patients infected with HBV. We found anti-PD-1 therapy achieved much better outcomes in HBV+ non-liver cancer patients than their HBV- counterparts. We performed single-cell RNA sequencing (scRNA-seq) on peripheral blood mononuclear cells (PBMCs) from esophageal squamous cell carcinoma (ESCC) patients. We found both cytotoxicity score of T cells and MHC score of B cells significantly increased after anti-PD-1 therapy in HBV+ ESCC patients. We also identified CX3CR1^high T_EFF, a subset of CD8⁺ T_EFF, associated with better clinical outcome in HBV+ ESCC patients. Lastly, we found CD8⁺ T_EFF from HBV+ ESCC patients showing higher fraction of Exhaustion^hi T than their HBV- counterpart. In summary, anti-PD-1 therapy on HBV+ non-liver cancer patients is safe and achieves better outcomes than that on HBV- non-liver cancer patients, potentially because HBV+ patients had higher fraction of Exhaustion^hi T, which made them more efficiently respond to anti-PD-1 therapy.

Comprehensive analysis of the immunological implication and prognostic value of CXCR4 in non-small cell lung cancer

CXCR4 (C-X-C chemokine receptor type 4) is the most commonly expressed of all chemokine receptors in malignant tumors. However, studies on CXCR4 in non-small cell lung cancer (NSCLC) tumor immune microenvironment, including those determining its immune efficacy and prognostic potential, are still scarce. Therefore, in this study, we determined the ability of CXCR4 to predict immunotherapy response and prognosis in NSCLC using immunohistochemical staining and RT-PCR, respectively, in two independent cohorts from the National Cancer Center of China. We analyzed transcriptome sequencing data and clinical information from multiple public databases to assess immune cell infiltration in NSCLC and constructed immune risk prognostic signatures based on CXCR4-related immunomodulators. We found that immune cell infiltration is significant differences in NSCLC tissues and is moderately correlated with CXCR4 expression. High CXCR4 expression was significantly associated with poor prognosis in NSCLC patients and a higher response rate to immunotherapy. The ROC curve showed that CXCR4 expression exhibited excellent performance in predicting the efficacy of immunotherapy in NSCLC. We identified 30 CXCR4-related immunomodulators in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) and constructed immune prognostic signatures based on CXCR4-related immunomodulators and CXCR4-related mutant genes. The signature-based prognostic risk score showed good performance in predicting patient prognosis in both LUAD and LUSC; high risk scores were significantly associated with poor prognosis (P < 0.0001) and was established as an independent prognostic factor by multivariate Cox regression. We postulate that CXCR4 is a potential predictive marker of immunotherapy efficacy in NSCLC and should be used in clinical settings. Moreover, the constructed signatures may be valuable in predicting patient prognosis in NSCLC.

Tissue-resident CXCR4+ macrophage as a poor prognosis signature promotes pancreatic ductal adenocarcinoma progression

Macrophage is an essential part of the tumor immune microenvironment of pancreatic ductal adenocarcinoma. In our study, we explored the CXCR4⁺ macrophages subset on its prognosis value, immune profile and distinct function in pancreatic cancer progression. Specimens from 102 postoperative pancreatic patients were analyzed by flow cytometry or immune-fluorescence, and the prognostic value of CXCR4⁺ macrophages infiltration was further determined by Cox regression. In silico analysis on TCGA, ICGC database and single-cell sequencing of pancreatic ductal adenocarcinoma further validated our findings. We found that high CXCR4⁺ macrophages infiltration was associated with poor overall survival (P < .01) and disease-free survival (P < .05) as an independent factor. CXCR4⁺ macrophages exhibited an M2 protumor phenotype with high expression of CD206. The function of CXCR4⁺ macrophages was further analyzed in the murine orthotopic PDAC model with its tumor promotion effect and inhibition of CD8⁺ T cells. Mechanistic and RNA-seq analysis showed that CXCR4⁺ macrophages participated in extracellular matrix remodeling procedures and especially secreted SPARC through CXCR4/PI3K/Akt pathway promoting tumor proliferation and migration. Our study reveals that CXCR4⁺ macrophages infiltration is an indicator of poor prognosis of PDAC and targeting these cells was potentially crucial in immunotherapy of PDAC.

Blockade of interleukin 10 potentiates antitumour immune function in human colorectal cancer liver metastases

OBJECTIVE

Programmed cell death protein 1 (PD-1) checkpoint inhibition and adoptive cellular therapy have had limited success in patients with microsatellite stable colorectal cancer liver metastases (CRLM). We sought to evaluate the effect of interleukin 10 (IL-10) blockade on endogenous T cell and chimeric antigen receptor T (CAR-T) cell antitumour function in CRLM slice cultures.

DESIGN

We created organotypic slice cultures from human CRLM (n=38 patients' tumours) and tested the antitumour effects of a neutralising antibody against IL-10 (αIL-10) both alone as treatment and in combination with exogenously administered carcinoembryonic antigen (CEA)-specific CAR-T cells. We evaluated slice cultures with single and multiplex immunohistochemistry, in situ hybridisation, single-cell RNA sequencing, reverse-phase protein arrays and time-lapse fluorescent microscopy.

RESULTS

αIL-10 generated a 1.8-fold increase in T cell-mediated carcinoma cell death in human CRLM slice cultures. αIL-10 significantly increased proportions of CD8⁺ T cells without exhaustion transcription changes, and increased human leukocyte antigen - DR isotype (HLA-DR) expression of macrophages. The antitumour effects of αIL-10 were reversed by major histocompatibility complex class I or II (MHC-I or MHC-II) blockade, confirming the essential role of antigen presenting cells. Interrupting IL-10 signalling also rescued murine CAR-T cell proliferation and cytotoxicity from myeloid cell-mediated immunosuppression. In human CRLM slices, αIL-10 increased CEA-specific CAR-T cell activation and CAR-T cell-mediated cytotoxicity, with nearly 70% carcinoma cell apoptosis across multiple human tumours. Pretreatment with an IL-10 receptor blocking antibody also potentiated CAR-T function.

CONCLUSION

Neutralising the effects of IL-10 in human CRLM has therapeutic potential as a stand-alone treatment and to augment the function of adoptively transferred CAR-T cells.

A combination therapy of bortezomib, CXCR4 inhibitor, and checkpoint inhibitor is effective in cholangiocarcinoma in vivo

Cholangiocarcinoma (CCA) is a biliary tree malignancy with a dismal prognosis. Tumor microenvironment (TME), including cancer-associated fibroblasts (CAFs) has been shown to be involved in drug resistance. To model the interactions between cancer cells and the TME, we established CCA complex patient-derived organoids (cPDOs) to include epithelial PDO (ePDOs) and matched CAFs. While ePDOs were sensitive to bortezomib, we found the matched cPDOs were relatively resistant. Mechanistically, this resistance was correlated with over-expression of CXCR4 in the CAF component of cPDOs. In accord with the role of CXCR4 in the resistance to bortezomib, we found that a CXCR4 inhibitor can reverse the resistance to bortezomib in vivo. Furthermore, we found that the inhibition of CXCR4 allowed bortezomib to sensitize CCA to anti-PD1 treatment, with a significant reduction of tumor burden and long-term overall survival. This novel cancer/stroma/immune triple treatment holds great promise for the treatment of CCA.

ELK3-CXCL16 axis determines natural killer cell cytotoxicity via the chemotactic activity of CXCL16 in triple negative breast cancer

Triple-negative breast cancer (TNBC) is the most challenging subtype of breast cancer because of its aggressive behavior and the limited therapeutic strategies available. In the last decade, immunotherapy has become a promising treatment to prolong survival in advanced solid cancers including TNBC. However, the efficacy of immunotherapy in solid cancers remains limited because solid tumors contain few tumor-infiltrating lymphocytes. Here, we show that targeting an ETS transcription factor ELK3 (ELK3) recruits immune cells including natural killer (NK) cells into tumors via the chemotactic activity of chemokine. ELK3 depletion increases CXCL16 expression level and promotes NK cell cytotoxicity through CXCL16-mediated NK cell recruitment in TNBC. In silico analysis showed that ELK3 is negatively correlated with CXCL16 expression in breast cancer patient samples. Low expression of ELK3 and high expression of CXCL16 were associated with a better prognosis. Low expression of ELK3 and high expression of CXCL16 were associated with increased expression of NK cell-related genes. Our findings demonstrate that the ELK3-CXCL16 axis modulates NK cell recruitment to increase NK cell cytotoxicity, suggesting that targeting the ELK3 gene could be an adjuvant strategy for increasing the efficacy of immunotherapy in TNBC.

Recent progress in cancer immunotherapy: Overview of current status and challenges

Cancer treatment is presently one of the most important challenges in medical science. Surgery, chemotherapy, radiotherapy, or combining these methods is used to eliminate the tumor. Hormone therapy, bone marrow transplantation, stem cell therapy as well as immunotherapy are other well-known therapeutic modalities. Immunotherapy, as the most important complementary method, uses the immune system for treating cancer followed by surgery, chemotherapy, and radiotherapy. This method is systematically used to prevent malignancies development mainly via potentiating antitumor immune cells activation and conversely compromising their exhaustion with the lowest negative effects on healthy cells. Active immunotherapy can be employed for cancer immunotherapy by directly using the ingredients of the immune system and activating immune responses. On the other hand, inactive immunotherapy is utilized by indirect induction and using immune cell-based products consisting of monoclonal antibodies. It has strongly been proved that combination therapy with immunotherapies and other therapeutic means, such as anti-angiogenic agents, could be a rational plan to treat cancer. Herein, we have focused on recent findings concerning the therapeutic merits of cancer therapy using immune checkpoint inhibitors (ICIs), adoptive cell transfer (ACT) and cancer vaccine alone or in combination with other approaches. Also, we offer a glimpse into the current challenges in this context.

Therapeutic Perspectives of HIV-Associated Chemokine Receptor (CCR5 and CXCR4) Antagonists in Carcinomas

The interaction between malignant cells and the tumor microenvironment is critical for tumor progression, and the chemokine ligand/receptor axes play a crucial role in this process. The CXCR4/CXCL12 and CCR5/CCL5 axes, both related to HIV, have been associated with the early (epithelial-mesenchymal transition and invasion) and late events (migration and metastasis) of cancer progression. In addition, these axes can also modulate the immune response against tumors. Thus, antagonists against the receptors of these axes have been proposed in cancer therapy. Although preclinical studies have shown promising results, clinical trials are needed to include these drugs in the oncological treatment protocols. New alternatives for these antagonists, such as dual CXCR4/CCR5 antagonists or combined therapy in association with immunotherapy, need to be studied in cancer therapy.

The prospect of tumor microenvironment-modulating therapeutical strategies

Multiple mechanisms promote tumor prosperity, which does not only depend on cell-autonomous, inherent abnormal characteristics of the malignant cells that facilitate rapid cell division and tumor expansion. The neoplastic tissue is embedded in a supportive and dynamic tumor microenvironment (TME) that nurtures and protects the malignant cells, maintaining and perpetuating malignant cell expansion. The TME consists of different elements, such as atypical vasculature, various innate and adaptive immune cells with immunosuppressive or pro-inflammatory properties, altered extracellular matrix (ECM), activated stromal cells, and a wide range of secreted/stroma-tethered bioactive molecules that contribute to malignancy, directly or indirectly. In this review, we describe the various TME components and provide examples of anti-cancer therapies and novel drugs under development that aim to target these components rather than the intrinsic processes within the malignant cells. Combinatory TME-modulating therapeutic strategies may be required to overcome the resistance to current treatment options and prevent tumor recurrence.

Utilization of macrocyclic peptides to target protein-protein interactions in cancer

Protein-protein interactions (PPIs) play vital roles in normal cellular processes. Dysregulated PPIs are involved in the process of various diseases, including cancer. Thus, these PPIs may serve as potential therapeutic targets in cancer treatment. However, despite rapid advances in small-molecule drugs and biologics, it is still hard to target PPIs, especially for those intracellular PPIs. Macrocyclic peptides have gained growing attention for their therapeutic properties in targeting dysregulated PPIs. Macrocyclic peptides have some unique features, such as moderate sizes, high selectivity, and high binding affinities, which make them good drug candidates. In addition, some oncology macrocyclic peptide drugs have been approved by the US Food and Drug Administration (FDA) for clinical use. Here, we reviewed the recent development of macrocyclic peptides in cancer treatment. The opportunities and challenges were also discussed to inspire new perspectives.

Facts and Hopes in Immunotherapy of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most challenging cancers to treat. For patients with advanced and metastatic disease, chemotherapy has yielded only modest incremental benefits, which are not durable. Immunotherapy has revolutionized the treatment of other solid tumors by leading to cures where none existed only a decade ago, yet it has made few inroads with PDAC. A host of trials with promising preclinical data have failed, except for in a small minority of patients with selected biomarkers. There is, however, a glimmer of hope, which we seek to cultivate. In this review, we discuss recent advances in the understanding of the uniquely immunosuppressive tumor microenvironment (TME) in PDAC, learnings from completed trials of checkpoint inhibitors, TME modifiers, cellular and vaccine therapies, oncolytic viruses, and other novel approaches. We go on to discuss our expectations for improved preclinical models of immunotherapy in PDAC, new approaches to modifying the TME including the myeloid compartment, and emerging biomarkers to better select patients who may benefit from immunotherapy. We also discuss improvements in clinical trial design specific to immunotherapy that will help us better measure success when we find it. Finally, we discuss the urgent imperative to better design and execute bold, but rational, combination trials of novel agents designed to cure patients with PDAC.

Targeting vasoactive intestinal peptide-mediated signaling enhances response to immune checkpoint therapy in pancreatic ductal adenocarcinoma

A paucity of effector T cells within tumors renders pancreatic ductal adenocarcinoma (PDAC) resistant to immune checkpoint therapies. While several under-development approaches target immune-suppressive cells in the tumor microenvironment, there is less focus on improving T cell function. Here we show that inhibiting vasoactive intestinal peptide receptor (VIP-R) signaling enhances anti-tumor immunity in murine PDAC models. In silico data mining and immunohistochemistry analysis of primary tumors indicate overexpression of the neuropeptide vasoactive intestinal peptide (VIP) in human PDAC tumors. Elevated VIP levels are also present in PDAC patient plasma and supernatants of cultured PDAC cells. Furthermore, T cells up-regulate VIP receptors after activation, identifying the VIP signaling pathway as a potential target to enhance T cell function. In mouse PDAC models, VIP-R antagonist peptides synergize with anti-PD-1 antibody treatment in improving T cell recruitment into the tumors, activation of tumor-antigen-specific T cells, and inhibition of T cell exhaustion. In contrast to the limited single-agent activity of anti-PD1 antibodies or VIP-R antagonist peptides, combining both therapies eliminate tumors in up to 40% of animals. Furthermore, tumor-free mice resist tumor re-challenge, indicating anti-cancer immunological memory generation. VIP-R signaling thus represents a tumor-protective immune-modulatory pathway that is targetable in PDAC.

CXCR4-CXCL12-CXCR7 and PD-1/PD-L1 in Pancreatic Cancer: CXCL12 Predicts Survival of Radically Resected Patients

Pancreatic ductal adenocarcinoma (PDAC) is currently the most deadly cancer. Although characterized by 5-20% of neoplastic cells in the highly fibrotic stroma, immunotherapy is not a valid option in PDAC treatment. As CXCR4-CXCL12 regulates tumor invasion and T-cell access and PD-1/PD-L1 controls immune tolerance, 76 PDACs were evaluated for CXCR4-CXCL12-CXCR7 and PD-1/PD-L1 in the epithelial and stromal component. Neoplastic CXCR4 and CXCL12 discriminated PDACs for recurrence-free survival (RFS), while CXCL12 and CXCR7 discriminated patients for cancer-specific survival (CSS). Interestingly, among patients with radical resection (R0), high tumor CXCR4 clustered patients with worse RFS, high CXCL12 identified poor prognostic patients for both RFS and CSS, while stromal lymphocytic-monocytic PD-L1 associated with improved RFS and CSS. PD-1 was only sporadically expressed (<1%) in focal lymphocyte infiltrate and does not impact prognosis. In multivariate analysis, tumoral CXCL12, perineural invasion, and AJCC lymph node status were independent prognostic factors for RFS; tumoral CXCL12, AJCC Stage, and vascular invasion were independent prognostic factors for CSS. CXCL12's poor prognostic meaning was confirmed in an additional perspective-independent 13 fine-needle aspiration cytology advanced stage-PDACs. Thus, CXCR4-CXCL12 evaluation in PDAC identifies prognostic categories and could orient therapeutic approaches.

CommPath: An R package for inference and analysis of pathway-mediated cell-cell communication chain from single-cell transcriptomics

Single-cell transcriptomics offers opportunities to investigate ligand-receptor (LR) interactions between heterogeneous cell populations within tissues. However, most existing tools for the inference of intercellular communication do not allow prioritization of functional LR associations that provoke certain biological responses in the receiver cells. In addition, current tools do not enable the identification of the impact on the downstream cell types of the receiver cells. We present CommPath, an open-source R package and webserver, to analyze and visualize the LR interactions and pathway-mediated intercellular communication chain with single-cell transcriptomic data. CommPath curates a comprehensive signaling pathway database to interpret the consequences of LR associations and therefore infers functional LR interactions. Furthermore, CommPath determines cell-cell communication chain by considering both the upstream and downstream cells of user-defined cell populations. Applying CommPath to human hepatocellular carcinoma dataset shows its ability to decipher complex LR interaction patterns and the associated intercellular communication chain, as well as their changes in disease versus homeostasis.

Identification and validation of prognostic autophagy-related genes associated with immune microenvironment in human gastric cancer

Autophagy-related genes (ATGs) play critical roles in tumorigenesis and progression in gastric cancer (GC). The present study aimed to identify immune-based prognostic ATGs and verify their functions in tumor immune microenvironment (TIME) in GC. Macrophage infiltration was found to negatively correlate with prognosis in GC patients. After stratifying by infiltration levels of macrophages, we screened The Cancer Genome Atlas and Human Autophagy Database to identify the differentially expressed ATGs (DE-ATGs). Of 1,433 differentially expressed genes between the two groups, seven genes qualified as DE-ATGs. Of these, CXCR4, DLC1, and MAP1LC3C, exhibited strong prognostic prediction ability in Kaplan-Meier survival–log-rank test. High expression of these genes correlated with increased occurrence of advanced grade 3 tumors and poor prognoses. Furthermore, GSEA indicated that they were significantly associated with oncogenic and immune-related pathways. The comprehensive evaluation of TIME via GEPIA, ESTIMATE, CIBERSORT, and TIMER suggested that the three DE-ATGs were closely associated with immune condition, both in terms of immune cells and immune scores. Thus, the outcome of this study may aid in better understanding of the ATGs and their interaction with the immune microenvironment, which would allow the development of novel inhibitors, personalized treatment, and immunotherapy in gastric cancer.

The Role of Immunotherapy in Pancreatic Cancer

Pancreatic adenocarcinoma remains one of the most lethal cancers globally, with a significant need for improved therapeutic options. While the recent breakthroughs of immunotherapy through checkpoint inhibitors have dramatically changed treatment paradigms in other malignancies based on considerable survival benefits, this is not so for pancreatic cancer. Chemotherapies with modest benefits are still the cornerstone of advanced pancreatic cancer treatment. Pancreatic cancers are inherently immune-cold tumors and have been largely refractory to immunotherapies in clinical trials. Understanding and overcoming the current failures of immunotherapy through elucidating resistance mechanisms and developing novel therapeutic approaches are essential to harnessing the potential durable benefits of immune-modulating therapy in pancreatic cancer patients.

Targeting Cellular Components of the Tumor Microenvironment in Solid Malignancies

Cancers are composed of transformed cells, characterized by aberrant growth and invasiveness, in close relationship with non-transformed healthy cells and stromal tissue. The latter two comprise the so-called tumor microenvironment (TME), which plays a key role in tumorigenesis, cancer progression, metastatic seeding, and therapy resistance. In these regards, cancer-TME interactions are complex and dynamic, with malignant cells actively imposing an immune-suppressive and tumor-promoting state on surrounding, non-transformed, cells. Immune cells (both lymphoid and myeloid) can be recruited from the circulation and/or bone marrow by means of chemotactic signals, and their functionality is hijacked upon arrival at tumor sites. Molecular characterization of tumor-TME interactions led to the introduction of novel anti-cancer therapies targeting specific components of the TME, such as immune checkpoint blockers (ICB) (i.e., anti-programmed death 1, anti-PD1; anti-Cytotoxic T-Lymphocyte Antigen 4, anti-CTLA4). However, ICB resistance often develops and, despite the introduction of newer technologies able to study the TME at the single-cell level, a detailed understanding of all tumor-TME connections is still largely lacking. In this work, we highlight the main cellular and extracellular components of the TME, discuss their dynamics and functionality, and provide an outlook on the most relevant clinical data obtained with novel TME-targeting agents, with a focus on T lymphocytes, macrophages, and cancer-associated fibroblasts.

Combination immunotherapy for pancreatic cancer: challenges and future considerations

INTRODUCTION

: Immune checkpoint inhibitors (ICI) have not yielded significant efficacy in pancreatic ductal adenocarcinoma (PDA), despite the role of the innate and adaptive immune systems on progression and survival. However, recently identified pathways have identified new targets and generated promising clinical investigations into promoting an effective immune-mediated antitumor response in PDA.

AREAS COVERED

: We review biological mechanisms associated with immunotherapy resistance and outline strategies for therapeutic combinations with established and novel therapies in PDA.

EXPERT OPINION

: Pancreatic cancers rarely benefits from treatment with ICI due to an immunosuppressive tumor microenvironment (TME). New understandings of factors associated with the suppressive TME, include low and poor quality neoantigens, constrained effector T cells infiltration, and the presence of a dense, suppressive myeloid cell population. These findings have been translated into new clinical investigations evaluating novel therapies in combination with ICI and/or standard systemic chemotherapy and radiotherapy. The epithelial, immune, and stromal compartments are intricately related in PDA, and the framework for successful targeting of this disease requires a comprehensive and personalized approach.

Clinical Strategies Targeting the Tumor Microenvironment of Pancreatic Ductal Adenocarcinoma

Pancreatic cancer has a complex tumor microenvironment which engages in extensive crosstalk between cancer cells, cancer-associated fibroblasts, and immune cells. Many of these interactions contribute to tumor resistance to anti-cancer therapies. Here, new therapeutic strategies designed to modulate the cancer-associated fibroblast and immune compartments of pancreatic ductal adenocarcinomas are described and clinical trials of novel therapeutics are discussed. Continued advances in our understanding of the pancreatic cancer tumor microenvironment are generating stromal and immune-modulating therapeutics that may improve patient responses to anti-tumor treatment.

Drug-induced tumor-specific cytotoxicity in a whole tissue ex vivo model of human pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer. PDAC has a dismal prognosis and an inherent resistance to cytostatic drugs. The lack of reliable experimental models is a severe limitation for drug development targeting PDAC. We have employed a whole tissue ex vivo culture model to explore the effect of redox-modulation by sodium selenite on the viability and growth of PDAC. Drug-resistant tumors are more vulnerable to redox-active selenium compounds because of high metabolic activity and redox imbalance. Sodium selenite efficiently and specifically reduced PDAC cell viability (p <0.02) (n=8) and decreased viable de novo tumor cell outgrowth (p<0.05) while preserving non-neoplastic tissues. Major cellular responses (damaged tumor cells > 90%, tumor regression grades III-IV according to Evans) were observed for sodium selenite concentrations between 15-30 µM. Moreover, selenium levels used in this study were significantly below the previously reported maximum tolerated dose for humans. Transcriptome data analysis revealed decreased expression of genes known to drive PDAC growth and metastatic potential (CEMIP, DDR2, PLOD2, P4HA1) while the cell death-inducing genes (ATF3, ACHE) were significantly upregulated (p<0.0001). In conclusion, we report that sodium selenite has an extraordinary efficacy and specificity against drug-resistant pancreatic cancer in an organotypic slice culture model. Our ex vivo organotypic tissue slice culture model can be used to test a variety of drug candidates for swift and reliable drug responses to individual PDAC cases.

Chemokine Receptor Expression on T Cells Is Modulated by CAFs and Chemokines Affect the Spatial Distribution of T Cells in Pancreatic Tumors

Simple Summary

The infiltration of T cells in pancreatic tumors has been correlated with better overall survival. However, the dense desmoplastic stroma, mainly composed by cancer-associated fibroblasts (CAFs), can sequester the T cells in the stroma preventing them from reaching the tumor nests. Chemokines are small molecules capable of directing T cell migration. Here, we explored whether CAFs could modulate the expression of chemokine receptors on T cells and examined if the spatial distribution of T cells within tumors was correlated to chemokine secretion patterns. Overall, we found that CXCR3 ligands was associated with an increased number of T cells in tumor rich areas and that CAFs downregulated the expression of CXCR3 on T cells. Understanding the mechanisms by which T cells are prevented from reaching the tumor nests is of great importance for the development of novel targeting therapies.

Abstract

The accumulation of T cells is associated with a better prognosis in pancreatic cancer. However, the immunosuppressive tumor microenvironment, largely composed by cancer-associated fibroblasts (CAFs), can prevent T cells from reaching the tumor nests. We examined how human CAFs modulated chemokine receptors known to be associated with T cell trafficking, CXCR3 and CCR5, and T cell exclusion, CXCR4. CAFs decreased the expression of CXCR3 and CCR5 but increased CXCR4 expression in both 2D and 3D cultures, affecting the migratory capacity of T cells towards CXCL10. An immunohistochemistry analysis showed that very few T cells were found in the tumor nests. Within the stroma, CD8⁺ T cells were localized more distantly from the malignant cells whereas CD4⁺ T cells were more equally distributed. Tumor tissues with a high production of chemokines were associated with less T cell infiltration when the whole tissue was analyzed. However, when the spatial localization of CD8⁺ T cells within the tissue was taken into account, levels of CXCR3 ligands and the CCR5 ligand CCL8 showed a positive association with a high relative T cell infiltration in tumor-rich areas. Thus, CXCR3 ligands could mediate T cell trafficking but CAFs could prevent T cells from reaching the malignant cells.

Mavorixafor, an Orally Bioavailable CXCR4 Antagonist, Increases Immune Cell Infiltration and Inflammatory Status of Tumor Microenvironment in Patients with Melanoma

Purpose

Mavorixafor is an oral, selective inhibitor of the CXCR4 chemokine receptor that modulates immune cell trafficking. A biomarker-driven phase Ib study (NCT02823405) was conducted in 16 patients with melanoma to investigate the hypothesis that mavorixafor favorably modulates immune cell profiles in the tumor microenvironment (TME) and to evaluate the safety of mavorixafor alone and in combination with pembrolizumab.

Experimental Design

Serial biopsies of melanoma lesions were assessed after 3 weeks of mavorixafor monotherapy and after 6 weeks of combination treatment for immune cell markers by NanoString analysis for gene expression and by multiplexed immunofluorescent staining for in situ protein expression. Serum samples taken at biopsy timepoints were evaluated for key chemokine and cytokine alterations using the Myriad Rules Based Medicine multiplex immunoassays.

Results

Within the TME, mavorixafor alone increased CD8⁺ T-cell infiltration, granzyme B signal, antigen presentation machinery, and both tumor inflammatory signature (TIS) and IFNγ gene expression signature scores. Increases in the key serum cytokines CXCL9 and CXCL10 were further enhanced when mavorixafor was combined with pembrolizumab. Adverse events (AE), as assessed by the investigator according to NCI Common Terminology Criteria for Adverse Events (v4.03), related to either mavorixafor or pembrolizumab (≥15%) were diarrhea, fatigue, maculopapular rash, and dry eye. Reported AEs were all ≤ grade 3.

Conclusion/Discussion

Treatment with single-agent mavorixafor resulted in enhanced immune cell infiltration and activation in the TME, leading to increases in TIS and IFNγ gene signatures. Mavorixafor as a single agent, and in combination with pembrolizumab, has an acceptable safety profile. These data support further investigation of the use of mavorixafor for patients unresponsive to checkpoint inhibitors.

Significance

Despite survival improvements in patients with melanoma treated with checkpoint inhibitor therapy, a significant unmet medical need exists for therapies that enhance effectiveness. We propose that mavorixafor sensitizes the melanoma tumor microenvironment and enhances the activity of checkpoint inhibitors, and thereby may translate to a promising treatment for broader patient populations.

CD40 Agonists Alter the Pancreatic Cancer Microenvironment by Shifting the Macrophage Phenotype toward M1 and Suppress Human Pancreatic Cancer in Organotypic Slice Cultures

Background/Aims

CD40 agonists are thought to generate antitumor effects on pancreatic cancer via macrophages and T cells. We aimed to investigate the role of CD40 agonists in the differentiation of macrophages and treatment of human pancreatic adenocarcinoma.

Methods

Immunohistochemistry was performed on paraffin-embedded surgical blocks from patients with pancreatic cancers to evaluate macrophage phenotypes and their relationship with survival. The effects of CD40 agonists on macrophage phenotypes and human pancreatic cancer were evaluated utilizing cell cocultures and organotypic slice cultures.

Results

CD163+ (predominant in M2 macrophages) and FOXP3+ (predominant in regulatory T cells) expression levels in the tumors were significantly lower in patients with stage IB pancreatic cancer than in those with stage II or III disease (p=0.002 and p=0.003, respectively). Patients with high CD163+ expression had shorter overall survival than those with low CD163+ expression (p=0.002). In vitro treatment of THP-1 macrophages with a CD40 agonist led to an increase in HLA-DR+ (predominant in M1 macrophages) and a decrease in CD163+ expression in THP-1 cells. Cell cocultures showed that CD40 agonists facilitate the suppression of PANC-1 human pancreatic cancer cells by THP-1 macrophages. Organotypic slice cultures showed that CD40 agonists alter the pancreatic cancer microenvironment by shifting the macrophage phenotype toward M1 (increase HLA-DR+ and decrease CD163+ expression), decreasing the abundance of regulatory T cells, and increasing tumor cell apoptosis.

Conclusions

CD163 is related to advanced human pancreatic cancer stages and shorter overall survival. CD40 agonists alter macrophage phenotype polarization to favor the M1 phenotype and suppress human pancreatic cancer.

Interaction of immune checkpoint PD-1 and chemokine receptor 4 (CXCR4) promotes a malignant phenotype in pancreatic cancer cells

Despite recent therapeutic advances, pancreatic ductal adenocarcinoma (PDAC) remains a devastating disease with limited therapeutic options. Immune checkpoint inhibitors (ICIs) have demonstrated promising results in many cancers, but thus far have yielded little clinical benefit in PDAC. Based on recent combined targeting of programmed cell death protein-1 (PD-1) and C-X-C chemokine receptor 4 (CXCR4) in patient-derived xenografts (PDXs) and a pilot clinical trial, we sought to elucidate potential interactions between PD-1 and CXCR4. We observed concomitant expression and direct interaction of PD-1 and CXCR4 in PDAC cells. This interaction was disrupted upon CXCR4 antagonism with AMD3100 and led to increased cell surface expression of PD-1. Importantly, CXCR4-mediated PDAC cell migration was also blocked by PD-1 inhibition. Our work provides a possible mechanism by which prior studies have demonstrated that combined CXCR4 and PD-1 inhibition leads to decreased tumor growth. This is the first report investigating PD-1 and CXCR4 interactions in PDAC cells and our results can serve as the basis for further investigation of combined therapeutic targeting of CXCR4 and PD-1.

Impact of tumor microenvironment on adoptive T cell transfer activity

Recent advances in immunotherapy have revolutionized the treatment of cancer. The use of adoptive cell therapies (ACT) such as those based on tumor infiltrating lymphocytes (TILs) or genetically modified cells (transgenic TCR lymphocytes or CAR-T cells), has shown impressive results in the treatment of several types of cancers. However, cancer cells can exploit mechanisms to escape from immunosurveillance resulting in many patients not responding to these therapies or respond only transiently. The failure of immunotherapy to achieve long-term tumor control is multifactorial. On the one hand, only a limited percentage of the transferred lymphocytes is capable of circulating through the bloodstream, interacting and crossing the tumor endothelium to infiltrate the tumor. Metabolic competition, excessive glucose consumption, the high level of lactic acid secretion and the extracellular pH acidification, the shortage of essential amino acids, the hypoxic conditions or the accumulation of fatty acids in the tumor microenvironment (TME), greatly hinder the anti-tumor activity of the immune cells in ACT therapy strategies. Therefore, there is a new trend in immunotherapy research that seeks to unravel the fundamental biology that underpins the response to therapy and identifies new approaches to better amplify the efficacy of immunotherapies. In this review we address important aspects that may significantly affect the efficacy of ACT, indicating also the therapeutic alternatives that are currently being implemented to overcome these drawbacks.

The Liver Pre-Metastatic Niche in Pancreatic Cancer: A Potential Opportunity for Intervention

Cancer-related mortality is primarily a consequence of metastatic dissemination and associated complications. Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies and tends to metastasize early, especially in the liver. Emerging evidence suggests that organs that develop metastases exhibit microscopic changes that favor metastatic growth, collectively known as "pre-metastatic niches". By definition, a pre-metastatic niche is chronologically established before overt metastatic outgrowth, and its generation involves the release of tumor-derived secreted factors that modulate cells intrinsic to the recipient organ, as well as recruitment of additional cells from tertiary sites, such as bone marrow-all orchestrated by the primary tumor. The pre-metastatic niche is characterized by tumor-promoting inflammation with tumor-supportive and immune-suppressive features, remodeling of the extracellular matrix, angiogenic modulation and metabolic alterations that support growth of disseminated tumor cells. In this paper, we review the current state of knowledge of the hepatic pre-metastatic niche in PDAC and attempt to create a framework to guide future diagnostic and therapeutic studies.

JAML promotes acute kidney injury mainly through a macrophage-dependent mechanism

Although macrophages are undoubtedly attractive therapeutic targets for acute kidney injury (AKI) because of their critical roles in renal inflammation and repair, the underlying mechanisms of macrophage phenotype switching and efferocytosis in the regulation of inflammatory responses during AKI are still largely unclear. The present study elucidated the role of junctional adhesion molecule–like protein (JAML) in the pathogenesis of AKI. We found that JAML was significantly upregulated in kidneys from 2 different murine AKI models including renal ischemia/reperfusion injury (IRI) and cisplatin-induced AKI. By generation of bone marrow chimeric mice, macrophage-specific and tubular cell–specific Jaml conditional knockout mice, we demonstrated JAML promoted AKI mainly via a macrophage-dependent mechanism and found that JAML-mediated macrophage phenotype polarization and efferocytosis is one of the critical signal transduction pathways linking inflammatory responses to AKI. Mechanistically, the effects of JAML on the regulation of macrophages were, at least in part, associated with a macrophage-inducible C-type lectin–dependent mechanism. Collectively, our studies explore for the first time to our knowledge new biological functions of JAML in macrophages and conclude that JAML is an important mediator and biomarker of AKI. Pharmacological targeting of JAML-mediated signaling pathways at multiple levels may provide a novel therapeutic strategy for patients with AKI.

Biomarkers and 3D models predicting response to immune checkpoint blockade in head and neck cancer (Review)

Immunotherapy has evolved into a powerful tool in the fight against a number of types of cancer, including head and neck squamous cell carcinomas (HNSCC). Although checkpoint inhibition (CPI) has definitely enriched the treatment options for advanced stage HNSCC during the past decade, the percentage of patients responding to treatment is widely varying between 14-32% in second-line setting in recurrent or metastatic HNSCC with a sporadic durability. Clinical response and, consecutively, treatment success remain unpredictable in most of the cases. One potential factor is the expression of target molecules of the tumor allowing cancer cells to acquire therapy resistance mechanisms. Accordingly, analyzing and modeling the complexity of the tumor microenvironment (TME) is key to i) stratify subgroups of patients most likely to respond to CPI and ii) to define new combinatorial treatment regimens. Particularly in a heterogeneous disease such as HNSCC, thoroughly studying the interactions and crosstalking between tumor and TME cells is one of the biggest challenges. Sophisticated 3D models are therefore urgently needed to be able to validate such basic science hypotheses and to test novel immuno-oncologic treatment regimens in consideration of the individual biology of each tumor. The present review will first summarize recent findings on immunotherapy, predictive biomarkers, the role of the TME and signaling cascades eliciting during CPI. Second, it will highlight the significance of current promising approaches to establish HNSCC 3D models for new immunotherapies. The results are encouraging and indicate that data obtained from patient-specific tumors in a dish might be finally translated into personalized immuno-oncology.

Immunotherapy in Pancreatic Cancer: Why Do We Keep Failing? A Focus on Tumor Immune Microenvironment, Predictive Biomarkers and Treatment Outcomes

Simple Summary

In pancreatic cancer, immunotherapy and targeted therapies have not brought about the therapeutic revolution that has been observed in other malignancies. Among the reasons to explain this difference is the possibly crucial role played by the pancreatic tumor microenvironment, which has unique features and is different from that of other neoplasms. The aim of this review is to provide a comprehensive overview of the distinctive tumor immune microenvironment of pancreatic cancer and to summarize existing data about the use of immunotherapy and immune biomarkers in this cancer.

Abstract

The advent of immunotherapy and targeted therapies has dramatically changed the outcomes of patients affected by many malignancies. Pancreatic cancer (PC) remains one the few tumors that is not treated with new generation therapies, as chemotherapy still represents the only effective therapeutic strategy in advanced-stage disease. Agents aiming to reactivate the host immune system against cancer cells, such as those targeting immune checkpoints, failed to demonstrate significant activity, despite the success of these treatments in other tumors. In many cases, the proportion of patients who derived benefits in early-phase trials was too small and unpredictable to justify larger studies. The population of PC patients with high microsatellite instability/mismatch repair deficiency is currently the only population that may benefit from immunotherapy; nevertheless, the prevalence of these alterations is too low to determine a real change in the treatment scenario of this tumor. The reasons for the unsuccess of immunotherapy may lie in the extremely peculiar tumor microenvironment, including distinctive immune composition and cross talk between different cells. These unique features may also explain why the biomarkers commonly used to predict immunotherapy efficacy in other tumors seem to be useless in PC. In the current paper, we provide a comprehensive and up-to-date review of immunotherapy in PC, from the analysis of the tumor immune microenvironment to immune biomarkers and treatment outcomes, with the aim to highlight that simply transferring the knowledge acquired on immunotherapy in other tumors might not be a successful strategy in patients affected by PC.

The Role of NcRNAs to Regulate Immune Checkpoints in Cancer

At present, the incidence of cancer is becoming more and more common, but its treatment has always been a problem. Although a small number of cancers can be treated, the recurrence rates are generally high and cannot be completely cured. At present, conventional cancer therapies mainly include chemotherapy and radiotherapy, which are the first-line therapies for most cancer patients, but there are palliatives. Approaches to cancer treatment are not as fast as cancer development. The current cancer treatments have not been effective in stopping the development of cancer, and cancer treatment needs to be imported into new strategies. Non-coding RNAs (ncRNAs) is a hot research topic at present. NcRNAs, which include microRNAs (miRNAs), circular RNAs (circRNAs), and long non-coding RNAs (lncRNAs), participate in all aspects of cancer biology. They are involved in the progression of tumors into a new form, including B-cell lymphoma, glioma, or the parenchymal tumors such as gastric cancer and colon cancer, among others. NcRNAs target various immune checkpoints to affect tumor proliferation, differentiation, and development. This might represent a new strategy for cancer treatment.

Multifunctional Lipid Bilayer Nanocarriers for Cancer Immunotherapy in Heterogeneous Tumor Microenvironments, Combining Immunogenic Cell Death Stimuli with Immune Modulatory Drugs

In addition to the contribution of cancer cells, the solid tumor microenvironment (TME) has a critical role in determining tumor expansion, antitumor immunity, and the response to immunotherapy. Understanding the details of the complex interplay between cancer cells and components of the TME provides an unprecedented opportunity to explore combination therapy for intervening in the immune landscape to improve immunotherapy outcome. One approach is the introduction of multifunctional nanocarriers, capable of delivering drug combinations that provide immunogenic stimuli for improvement of tumor antigen presentation, contemporaneous with the delivery of coformulated drug or synthetic molecules that provide immune danger signals or interfere in immune-escape, immune-suppressive, and T-cell exclusion pathways. This forward-looking review will discuss the use of lipid-bilayer-encapsulated liposomes and mesoporous silica nanoparticles for combination immunotherapy of the heterogeneous immune landscapes in pancreatic ductal adenocarcinoma and triple-negative breast cancer. We describe how the combination of remote drug loading and lipid bilayer encapsulation is used for the synthesis of synergistic drug combinations that induce immunogenic cell death, interfere in the PD-1/PD-L1 axis, inhibit the indoleamine-pyrrole 2,3-dioxygenase (IDO-1) immune metabolic pathway, restore spatial access to activated T-cells to the cancer site, or reduce the impact of immunosuppressive stromal components. We show how an integration of current knowledge and future discovery can be used for a rational approach to nanoenabled cancer immunotherapy.

The Trinity: Interplay among Cancer Cells, Fibroblasts, and Immune Cells in Pancreatic Cancer and Implication of CD8+ T Cell-Orientated Therapy

The microenvironment in tumors is complicated and is constituted by different cell types and stromal proteins. Among the cell types, the abundance of cancer cells, fibroblasts, and immune cells is high and these cells work as the “Trinity” in promoting tumorigenesis. Although unidirectional or bidirectional crosstalk between two independent cell types has been well characterized, the multi-directional interplays between cancer cells, fibroblasts, and immune cells in vitro and in vivo are still unclear. We summarize recent studies in addressing the interaction of the “Trinity” members in the tumor microenvironment and propose a functional network for how these members communicate with each other. In addition, we discuss the underlying mechanisms mediating the interplay. Moreover, correlations of the alterations in the distribution and functionality of cancer cells, fibroblasts, and immune cells under different circumstances are reviewed. Finally, we point out the future application of CD8⁺ T cell-oriented therapy in the treatment of pancreatic cancer.

Tumor immunotherapies by immune checkpoint inhibitors (ICIs); the pros and cons

The main breakthrough in tumor immunotherapy was the discovery of immune checkpoint (IC) proteins, which act as a potent suppressor of the immune system by a myriad of mechanisms. After that, scientists focused on the immune checkpoint molecules mainly. Thereby, much effort was spent to progress novel strategies for suppressing these inhibitory axes, resulting in the evolution of immune checkpoint inhibitors (ICIs). Then, ICIs have become a promising approach and shaped a paradigm shift in tumor immunotherapies. CTLA-4 plays an influential role in attenuation of the induction of naïve and memory T cells by engagement with its responding ligands like B7-1 (CD80) and B7-2 (CD86). Besides, PD-1 is predominantly implicated in adjusting T cell function in peripheral tissues through its interaction with programmed death-ligand 1 (PD-L1) and PD-L2. Given their suppressive effects on anti-tumor immunity, it has firmly been documented that ICIs based therapies can be practical and rational therapeutic approaches to treat cancer patients. Nonetheless, tumor inherent or acquired resistance to ICI and some treatment-related toxicities restrict their application in the clinic. The current review will deliver a comprehensive overview of the ICI application to treat human tumors alone or in combination with other modalities to support more desired outcomes and lower toxicities in cancer patients. Video Abstract.

Precision-Cut Tumor Slices (PCTS) as an Ex Vivo Model in Immunotherapy Research

Precision-cut tumor slices (PCTS) have recently emerged as important ex vivo human tumor models, offering the opportunity to study individual patient responses to targeted immunotherapies, including CAR-T cell therapies. In this review, an outline of different human tumor models available in laboratory settings is provided, with a focus on the unique characteristics of PCTS. Standard PCTS generation and maintenance procedures are outlined, followed by an in-depth overview of PCTS utilization in preclinical research aiming to better understand the unique functional characteristics of cytotoxic T cells within human tumors. Furthermore, recent studies using PCTS as an ex vivo model for predicting patient responses to immunotherapies and other targeted therapies against solid tumors are thoroughly presented. Finally, the advantages and limitations of the PCTS models are discussed. PCTS are expected to gain momentum and be fully utilized as a significant tool towards better patient stratification and personalized medicine.

Clinical relevance of tumour-associated macrophages

In the past decade, substantial advances have been made in understanding the biology of tumour-associated macrophages (TAMs), and their clinical relevance is emerging. A particular aspect that is becoming increasingly clear is that the interaction of TAMs with cancer cells and stromal cells in the tumour microenvironment enables and sustains most of the hallmarks of cancer. Therefore, manipulation of TAMs could enable improved disease control in a substantial fraction of patients across a large number of cancer types. In this Review, we examine the diversity of TAMs in various cancer indications and how this heterogeneity is being revisited with the advent of single-cell technologies, and then explore the current knowledge on the functional roles of different TAM states and the prognostic and predictive value of TAM-related signatures. We also review agents targeting TAMs that are currently being or will soon be tested in clinical trials, and how manipulations of TAMs can improve existing anticancer treatments. Finally, we discuss how TAM-targeting approaches could be further integrated into routine clinical practice, considering a precision oncology approach and viewing TAMs as a dynamic population that can evolve under treatment pressure.

A Phase 1/2 Trial Combining Avelumab and Trabectedin for Advanced Liposarcoma and Leiomyosarcoma

PURPOSE

Leiomyosarcoma (LMS) and liposarcoma (LPS) frequently express PD-L1 but are generally resistant to PD-1/PD-L1 inhibition (ICI). Trabectedin is FDA-approved for LMS and LPS. This study aimed to evaluate the safety and efficacy of trabectedin with anti-PD-L1 antibody avelumab in patients with advanced LMS and LPS.

PATIENTS AND METHODS

A single-arm, open-label, Phase 1/2 study tested avelumab with trabectedin for advanced LMS and LPS. The phase I portion evaluated safety and feasibility of trabectedin (1, 1.2 and 1.5 mg/m2) with avelumab at standard dosing. Primary endpoint of the phase II portion was objective response rate (ORR) by RECIST 1.1. Correlative studies included T-cell receptor sequencing (TCRseq), multiplex immunohistochemistry, and tumor gene expression.

RESULTS

33 patients were evaluable; 24 with LMS (6 uterine and 18 non-uterine) and 11 with LPS. In Phase 1, dose limiting toxicities (DLTs) were observed in 2 of 6 patients at both trabectedin 1.2 and 1.5 mg/m2. The recommended Phase 2 dose (RP2D) was 1.0 mg/m2 trabectedin and 800 mg avelumab. Of 23 patients evaluable at RP2D, three (13%) had partial response (PR), ten (43%) had stable disease (SD) as best response. 6-month PFS was 52%; median PFS was 8.3 months. Patients with PR had higher Simpson Clonality score on TCRseq from peripheral blood mononuclear cells (PBMC) versus those with SD (0.182 vs 0.067, p = 0.02) or PD (0.182 vs 0.064, p = 0.01).

CONCLUSIONS

Although the trial did not meet the primary ORR endpoint, PFS compared favorably to prior studies of trabectedin warranting further investigation.

Harnessing the chemokine system to home CAR-T cells into solid tumors

CAR-T cell therapy has been heralded as a breakthrough in the field of immunotherapy, but to date, this success has been limited to hematological malignancies. By harnessing the chemokine system and taking into consideration the chemokine expression profile in the tumor microenvironment, CAR-T cells may be homed into tumors to facilitate direct tumor cell cytolysis and overcome a major hurdle in generating effective CAR-T cell responses to solid cancers.

Correlation between Tumor Microenvironment and Immune Subtypes Based on CD8 T Cells Enhancing Personalized Therapy of Gastric Cancer

Background

Immunotherapy is a promising therapy for metastatic gastric cancer (GC) patients. However, the component of tumor microenvironment (TME) is a pivotal factor hindering immunotherapy outcome. CD8 T cells suppress tumor progression. This study developed an immune subtyping system and a prognostic model for guiding personalized therapy of GC patients.

Methods

Marker genes related to CD8 T cells were identified by weighted correlation network analysis (WGCNA). Consensus clustering was used to develop immune subtypes. Univariate Cox regression analysis was performed to screen prognostic genes. Functional analysis (KEGG and GO annotation) and gene set enrichment analysis were applied.

Results

Based on marker genes related to CD8 T cells, we identified three immune subtypes (IC1, IC2, and IC3) with distinct prognosis and differential TME. In IC3, CD8 T cell function was impaired by high activation of CXCR4/CXCL12 axis, and impaired T cell function predicted high response to immune checkpoint blockade. IC1 was sensitive to chemotherapeutic drugs but showed low response to immunotherapy. We also developed an 8-gene prognostic signature with robust performance to stratify GC patients into high-risk and low-risk groups.

Conclusions

This study identified three immune subtypes and a prognostic signature, and both were effective in direct personalized therapy for GC patients. The correlation between TME and immunotherapy was further characterized from a new perspective.

Mitophagy-Related Gene Signature for Prediction Prognosis, Immune Scenery, Mutation, and Chemotherapy Response in Pancreatic Cancer

Mitophagy is a conserved cellular process that plays a vital role in maintaining cellular homeostasis by selectively removing dysfunctional mitochondria. Notwithstanding that growing evidence suggests that mitophagy is implicated in pancreatic tumorigenesis, the effect of mitophagy-related genes on pancreatic cancer (PC) prognosis and therapeutic response remains largely unknown. In this study, we sought to construct a mitophagy-related gene signature and assessed its ability to predict the survival, immune activity, mutation status, and chemotherapy response of PC patients. During the screening process, we identified three mitophagy-related genes (PRKN, SRC, VDAC1) from The Cancer Genome Atlas (TCGA) cohort and a 3-gene signature was established. The prognostic model was validated using an International Cancer Genome Consortium (ICGC) cohort and two Gene Expression Omnibus (GEO) cohorts. According to the median risk score, PC patients were divided into high and low-risk groups, and the high-risk group correlated with worse survival in the four cohorts. The risk score was then identified as an independent prognostic predictor, and a predictive nomogram was constructed to guide clinical decision-making. Remarkably, enhanced immunosuppressive levels and higher mutation rates were observed in patients from the high-risk group, which may account for their poor survival. Furthermore, we found that high-risk patients were more sensitive to paclitaxel and erlotinib. In conclusion, a mitophagy-related gene signature is a novel prognostic model that can be used as a predictive indicator and allows prognostic stratification of PC patients.

Modulation of Type I Interferon Responses to Influence Tumor-Immune Cross Talk in PDAC

Immunotherapy has revolutionized the treatment of many cancer types. However, pancreatic ductal adenocarcinomas (PDACs) exhibit poor responses to immune checkpoint inhibitors with immunotherapy-based trials not generating convincing clinical activity. PDAC tumors often have low infiltration of tumor CD8+ T cells and a highly immunosuppressive microenvironment. These features classify PDAC as immunologically "cold." However, the presence of tumor T cells is a favorable prognostic feature in PDAC. Intrinsic tumor cell properties govern interactions with the immune system. Alterations in tumor DNA such as genomic instability, high tumor mutation burden, and/or defects in DNA damage repair are associated with responses to both immunotherapy and chemotherapy. Cytotoxic or metabolic stress produced by radiation and/or chemotherapy can act as potent immune triggers and prime immune responses. Damage- or stress-mediated activation of nucleic acid-sensing pathways triggers type I interferon (IFN-I) responses that activate innate immune cells and natural killer cells, promote maturation of dendritic cells, and stimulate adaptive immunity. While PDAC exhibits intrinsic features that have the potential to engage immune cells, particularly following chemotherapy, these immune-sensing mechanisms are ineffective. Understanding where defects in innate immune triggers render the PDAC tumor-immune interface less effective, or how T-cell function is suppressed will help develop more effective treatments and harness the immune system for durable outcomes. This review will focus on the pivotal role played by IFN-I in promoting tumor cell-immune cell cross talk in PDAC. We will discuss how PDAC tumor cells bypass IFN-I signaling pathways and explore how these pathways can be co-opted or re-engaged to enhance the therapeutic outcome.

Combination therapy for pancreatic cancer: anti-PD-(L)1-based strategy

Mortality associated with pancreatic cancer is among the highest of all malignancies, with a 5-year overall survival of 5-10%. Immunotherapy, represented by the blocking antibodies against programmed cell death protein 1 or its ligand 1 (anti-PD-(L)1), has achieved remarkable success in a number of malignancies. However, due to the immune-suppressive tumor microenvironment, the therapeutic efficacy of anti-PD-(L)1 in pancreatic cancer is far from expectation. To address such a fundamental issue, chemotherapy, radiotherapy, targeted therapy and even immunotherapy itself, have individually been attempted to combine with anti-PD-(L)1 in preclinical and clinical investigation. This review, with a particular focus on pancreatic cancer therapy, collects current anti-PD-(L)1-based combination strategy, highlights potential adverse effects of accumulative combination, and further points out future direction in optimization of combination, including targeting post-translational modification of PD-(L)1 and improving precision of treatment.

Impaired CXCL12 signaling contributes to resistance of pancreatic cancer subpopulations to T cell-mediated cytotoxicity

Pancreatic cancer remains largely unresponsive to immune modulatory therapy attributable in part to an immunosuppressive, desmoplastic tumor microenvironment. Here, we analyze mechanisms of cancer cell-autonomous resistance to T cells. We used a 3D co-culture model of cancer cell spheroids from the KPC (LSL-KrasG12D/+ /LSL-Trp53R172H/+ /p48-Cre) pancreatic ductal adenocarcinoma (PDAC) model, to examine interactions with tumor-educated T cells isolated from draining lymph nodes of PDAC-bearing mice. Subpopulations of cancer cells resistant to these tumor-educated T cells were isolated from the in vitro co-culture and their properties compared with sensitive cancer cells. In co-culture with resistant cancer cell subpopulations, tumor-educated T cells showed reduced effector T cell functionality, reduced infiltration into tumor cell spheroids and decreased induction of apoptosis. A combination of comparative transcriptomic analyses, cytometric and immunohistochemistry techniques allowed us to dissect the role of differential gene expression and signaling pathways between sensitive and resistant cells. A decreased expression of the chemokine CXCL12 (SDF-1) was revealed as a common feature in the resistant cell subpopulations. Adding back CXCL12 reversed the resistant phenotype and was inhibited by the CXCR4 inhibitor AMD3100 (plerixafor). We conclude that reduced CXCL12 signaling contributes to PDAC subpopulation resistance to T cell-mediated attack.

A Microfluidic Cancer-on-Chip Platform Predicts Drug Response Using Organotypic Tumor Slice Culture

Optimal treatment of cancer requires diagnostic methods to facilitate therapy choice and prevent ineffective treatments. Direct assessment of therapy response in viable tumor specimens could fill this diagnostic gap. Therefore, we designed a microfluidic platform for assessment of patient treatment response using tumor tissue slices under precisely controlled growth conditions. The optimized Cancer-on-Chip (CoC) platform maintained viability and sustained proliferation of breast and prostate tumor slices for 7 days. No major changes in tissue morphology or gene expression patterns were observed within this time frame, suggesting that the CoC system provides a reliable and effective way to probe intrinsic chemotherapeutic sensitivity of tumors. The customized CoC platform accurately predicted cisplatin and apalutamide treatment response in breast and prostate tumor xenograft models, respectively. The culture period for breast cancer could be extended up to 14 days without major changes in tissue morphology and viability. These culture characteristics enable assessment of treatment outcomes and open possibilities for detailed mechanistic studies. SIGNIFICANCE: The Cancer-on-Chip platform with a 6-well plate design incorporating silicon-based microfluidics can enable optimal patient-specific treatment strategies through parallel culture of multiple tumor slices and diagnostic assays using primary tumor material.

Diverse and precision therapies open new horizons for patients with advanced pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a common cause of cancer-related death, and most patients are with advanced disease when diagnosed. At present, despite a variety of treatments have been developed for PDAC, few effective treatment options are available; on the other hand, PDAC shows significant resistance to chemoradiotherapy, targeted therapy, and immunotherapy due to its heterogeneous genetic profile, molecular signaling pathways, and complex tumor immune microenvironment. Nevertheless, over the past decades, there have been many new advances in the key theory and understanding of the intrinsic mechanisms and complexity of molecular biology and molecular immunology in pancreatic cancer, based on which more and more diverse new means and reasonable combination strategies for PDAC treatment have been developed and preliminary breakthroughs have been made. With the continuous exploration, from surgical local treatment to comprehensive medical management, the research-diagnosis-management system of pancreatic cancer is improving. This review focused on the variety of treatments for advanced PDAC, including traditional chemotherapy, targeted therapy, immunotherapy, microenvironment matrix regulation as well as the treatment targeting epigenetics, metabolism and cancer stem cells. We pointed out the current research bottlenecks and future exploration directions.