Immunotherapy and Pancreatic Cancer: A Lost Challenge?

Threading the Needle: Navigating Novel Immunotherapeutics in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy with a poor prognosis. Currently, chemotherapy is the only option for most patients with advanced-stage PDAC. Further, conventional immunotherapies and targeted therapies improve survival outcomes only in rare PDAC patient subgroups. To date, combinatory immunotherapeutic strategies to overcome the immune-hostile PDAC tumor microenvironment (TME) have resulted in limited efficacy in clinical studies. However, efforts are ongoing to develop new treatment strategies for patients with PDAC with the evolving knowledge of the TME, molecular characterization, and immune resistance mechanisms. Further, the growing arsenal of various immunotherapeutic agents, including novel classes of immune checkpoint inhibitors and oncolytic, chimeric antigen receptor T cell, and vaccine therapies, reinforces these efforts. This review will focus on the place of immunotherapy and future possible strategies in PDAC.

TRAIL receptor agonist TLY012 in combination with PD-1 inhibition promotes tumor regression in an immune-competent mouse model of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) has an immunosuppressed, apoptosis-resistant phenotype. TLY012 is pegylated recombinant Tumor necrosis factor-Related Apoptosis-Inducing Ligand (TRAIL), an orphan drug for chronic pancreatitis and systemic sclerosis. Innate immune TRAIL signaling suppresses cancer. We hypothesized that the combination of immune checkpoint-blocking anti-PD-1 antibody and TLY012 would have synergistic anti-tumor efficacy in immune-competent PDAC-bearing mice. PDAC tumor-bearing C57Bl/6 mice treated with 10 mg/kg anti-mouse PD-1 antibody twice weekly and 10 mg/kg TLY012 three times weekly had reduced tumor growth and tumor volume at 70 days compared to either drug alone (all P < 0.005). B-cell activating factor (BAFF), which promotes PDAC tumors, decreased to 44% of control mice with dual treatment at 7 days and remained decreased at 3 months. Long-term dual treatment showed the highest plasma levels of proinflammatory cytokines interferon-gamma (average 5.6 times control level, P=0.046), CCL5 (average 14.1 times control level, P=0.048), and interleukin-3 (IL-3, average 71.1 times control level, P=0.0053). Flow cytometry showed trends toward decreased circulating regulatory T cells, increased NK cells, and a higher proportion of CD8+ T cells within tumors in the dual treatment group. In summary, the combination of anti-PD-1 and TLY012 prevented the growth of PDAC in an immunocompetent mouse model while increasing tumor-infiltrating CD8+ T cells, decreasing circulating T-regulatory cells and altering plasma cytokine expression of CCL5, interferon-gamma, and IL-3 to promote proinflammatory, antitumor effects. Combining TLY012 and anti-mouse PD-1 modifies immune cell and cytokine levels to induce a more proinflammatory immune environment that contributes to decreased PDAC tumor growth.

Oncolytic Coxsackievirus B3 Strain PD-H Is Effective Against a Broad Spectrum of Pancreatic Cancer Cell Lines and Induces a Growth Delay in Pancreatic KPC Cell Tumors In Vivo

Pancreatic cancer is one of the deadliest cancers globally, with limited success from existing therapies, including chemotherapies and immunotherapies like checkpoint inhibitors for patients with advanced pancreatic ductal adenocarcinoma (PDAC). A promising new approach is the use of oncolytic viruses (OV), a form of immunotherapy that has been demonstrated clinical effectiveness in various cancers. Here we investigated the potential of the oncolytic coxsackievirus B3 strain (CVB3) PD-H as a new treatment for pancreatic cancer. In vitro, PD-H exhibited robust replication, as measured by plaque assays, and potent lytic activity, as assessed by XTT assays, in most pancreatic tumor cell lines, outperforming two other coxsackievirus strains tested, H3N-375/1TS and CVA21. Thus, H3N-375/1TS showed efficient replication and lytic efficiency in distinctly fewer tumor cell lines, while most tumor cells were resistant to CVA21. The oncolytic efficiency of the three OV largely correlated with mRNA expression levels of viral receptors and their ability to induce apoptosis, as measured by cleaved caspase 3/7 activity in the tumor cells. In a syngeneic mouse model with subcutaneous pancreatic tumors, intratumoral administration of PD-H significantly inhibited tumor growth but did not completely stop tumor progression. Importantly, no virus-related side effects were observed. Although pancreatic tumors respond to PD-H treatment, its therapeutic efficacy is limited. Combining PD-H with other treatments, such as those aiming at reducing the desmoplastic stroma which impedes viral infection and spread within the tumor, may enhance its efficacy.

Inhibition of the PI3K/AKT/mTOR pathway in pancreatic cancer: is it a worthwhile endeavor?

Pancreatic cancer (PC) is an aggressive disease that is challenging to treat and is associated with a high mortality rate. The most common type of PC is pancreatic ductal adenocarcinoma (PDAC), and the existing treatment options are insufficient for PDAC patients. Due to the complexity and heterogeneity of PDAC, personalized medicine is necessary for effectively treating this illness. To achieve this, it is essential to understand the mechanism of PDAC carcinogenesis. Targeted therapies are a promising strategy to improve patient outcomes. Aberrant activation of the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway plays a crucial role in PC pathogenesis, from initiation to progression. This review provides a comprehensive overview of the current state of knowledge regarding the PI3K pathway in PDAC, summarizes clinical data on PI3K pathway inhibition in PDAC, and explores potential effective combinations that are a promising direction requiring further investigation in PDAC.

Modulation of PRC1 Promotes Anticancer Effects in Pancreatic Cancer

Background: Pancreatic cancer, while relatively uncommon, is extrapolated to become the second leading cause of cancer-related deaths worldwide. Despite identifying well-known markers like the KRAS gene, the exact regulation of pancreatic cancer progression remains elusive. Methods: Clinical value of PRC1 was analyzed using bioinformatics database. The role of PRC1 was further evaluated through cell-based assays, including viability, wound healing, and sensitivity with the drug. Results: We demonstrate that PRC1 was significantly overexpressed in pancreatic cancer compared to pancreases without cancer, as revealed through human databases and cell lines analysis. Furthermore, high PRC1 expression had a negative correlation with CD4+ T cells, which are crucial for the immune response against cancers. Additionally, PRC1 showed a positive correlation with established pancreatic cancer markers. Silencing PRC1 expression using siRNA significantly inhibited cancer cell proliferation and viability and increased chemotherapeutic drug sensitivity. Conclusions: These findings suggest that targeting PRC1 in pancreatic cancer may enhance immune cell infiltration and inhibit cancer cell proliferation, offering a promising avenue for developing anticancer therapies.

Autotaxin-Lysophosphatidate Axis: Promoter of Cancer Development and Possible Therapeutic Implications

Autotaxin (ATX) is a member of the ectonucleotide pyrophosphate/phosphodiesterase (ENPP) family; it is encoded by the ENPP2 gene. ATX is a secreted glycoprotein and catalyzes the hydrolysis of lysophosphatidylcholine to lysophosphatidic acid (LPA). LPA is responsible for the transduction of various signal pathways through the interaction with at least six G protein-coupled receptors, LPA Receptors 1 to 6 (LPAR1-6). The ATX-LPA axis is involved in various physiological and pathological processes, such as angiogenesis, embryonic development, inflammation, fibrosis, and obesity. However, significant research also reported its connection to carcinogenesis, immune escape, metastasis, tumor microenvironment, cancer stem cells, and therapeutic resistance. Moreover, several studies suggested ATX and LPA as relevant biomarkers and/or therapeutic targets. In this review of the literature, we aimed to deepen knowledge about the role of the ATX-LPA axis as a promoter of cancer development, progression and invasion, and therapeutic resistance. Finally, we explored its potential application as a prognostic/predictive biomarker and therapeutic target for tumor treatment.

Identification of pancreatic adenocarcinoma immune subtype associated with tumor neoantigen from aberrant alternative splicing

Background

Pancreatic adenocarcinoma (PAAD) is referred to as an immunologically "cold" tumor that responds poorly to immunotherapy. A fundamental theory that explains the low immunogenicity of PAAD is the dramatically low tumor mutation burden (TMB) of PAAD tumors, which fails to induce sufficient immune response. Alternative splicing of pre-mRNA, which could alter the proteomic diversity of many cancers, has been reported to be involved in neoantigen production. Therefore, we aim to identify novel PAAD antigens and immune subtypes through systematic bioinformatics research.

Methods

Data for splicing analysis were downloaded from The Cancer Genome Atlas (TCGA) SpliceSeq database. Among the available algorithms, we chose CIBERSORT to evaluate the immune cell distribution among PAADs. The TCGA-PAAD expression matrix was used to construct a co-expression network. Single-cell analysis was performed based on the Seurat workflow.

Results

Integrated analysis of aberrantly upregulated genes, alternatively spliced genes, genes associated with nonsense-mediated RNA decay (NMD) factors, antigen presentation and overall survival (OS) in TCGA-PAAD revealed that PLEC is a promising neoantigen for PAAD-targeted therapy. We identified a C2 TCGA-PAAD subtype that had better prognosis and more CD8+ T-cell infiltration. We propose a novel immune subtyping system for PAAD to indicate patient prognosis and opportunities for immunotherapy, such as immune checkpoint (ICP) inhibitors.

Conclusions

In conclusion, the present study used a transcriptome-guided approach to screen neoantigen candidates based on alternative splicing, NMD factors, and antigen-presenting signatures for PAAD. A prognosis model with guidance of immunotherapy will aid in patient selection for appropriate treatment.

Solute carrier family 16 member 1 as a potential prognostic factor for pancreatic ductal adenocarcinoma and its influence on tumor immunity

Background

Solute carrier family 16 member 1 (SLC16A1) serves as a biomarker in numerous types of cancer. Tumor immune infiltration has drawn increasing attention in cancer progression and treatment. The objective of our study was to explore the association between SLC16A1 and the tumor immune microenvironment in pancreatic ductal adenocarcinoma (PDAC).

Methods

Data were obtained from The Cancer Genome Atlas. The xCell web tool was used to calculate the proportion of immune cells according to SLC16A1 expression. To further explore the mechanism of SLC16A1, immunity-related genes were screened from differentially expressed genes through weighted gene coexpression network analysis, examined via Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses, and filtrated using univariate Cox regression and least absolute shrinkage and selection operator regression model combined correlation analysis (P<0.05). Next, CIBERSORT was used to analyze the correlation between immune cells and five important genes. SLC16A1 expression and its clinical role in pancreatic cancer was clarified via immunohistochemical staining experiments. Finally, the effects of SLC16A1 on the results of cancer immunity were evaluated by in vitro experiments.

Results

SLC16A1 was overexpressed in PDAC tissues and could be an independent prognostic factor. SLC16A1 was significantly negatively correlated with overall survival and suppressed the tumor immunity of PDAC. In clinic, SLC16A1 expression was significantly positively correlated with tumor progression and poor prognosis. We also found that SLC16A1 could suppress the antitumor ability of CD8+ T cells.

Conclusions

SLC16A1 is a biomarker for the prognosis of PDAC and can influence the immune environment of PDAC. These findings provide new insights into the treatment of PDAC.

Targeted Nanoparticle-Based Diagnostic and Treatment Options for Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC), one of the deadliest cancers, presents significant challenges in diagnosis and treatment due to its aggressive, metastatic nature and lack of early detection methods. A key obstacle in PDAC treatment is the highly complex tumor environment characterized by dense stroma surrounding the tumor, which hinders effective drug delivery. Nanotechnology can offer innovative solutions to these challenges, particularly in creating novel drug delivery systems for existing anticancer drugs for PDAC, such as gemcitabine and paclitaxel. By using customization methods such as incorporating conjugated targeting ligands, tumor-penetrating peptides, and therapeutic nucleic acids, these nanoparticle-based systems enhance drug solubility, extend circulation time, improve tumor targeting, and control drug release, thereby minimizing side effects and toxicity in healthy tissues. Moreover, nanoparticles have also shown potential in precise diagnostic methods for PDAC. This literature review will delve into targeted mechanisms, pathways, and approaches in treating pancreatic cancer. Additional emphasis is placed on the study of nanoparticle-based delivery systems, with a brief mention of those in clinical trials. Overall, the overview illustrates the significant advances in nanomedicine, underscoring its role in transcending the constraints of conventional PDAC therapies and diagnostics.

Chimeric Antigen Receptor T Cell Therapy for Pancreatic Cancer: A Review of Current Evidence

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of malignant and non-malignant disorders. CARs are synthetic transmembrane receptors expressed on genetically modified immune effector cells, including T cells, natural killer (NK) cells, or macrophages, which are able to recognize specific surface antigens on target cells and eliminate them. CAR-modified immune cells mediate cytotoxic antitumor effects via numerous mechanisms, including the perforin and granzyme pathway, Fas and Fas Ligand (FasL) pathway, and cytokine secretion. High hopes are associated with the prospective use of the CAR-T strategy against solid cancers, especially the ones resistant to standard oncological therapies, such as pancreatic cancer (PC). Herein, we summarize the current pre-clinical and clinical studies evaluating potential tumor-associated antigens (TAA), CAR-T cell toxicities, and their efficacy in PC.

PD-1 blockade combined with gemcitabine plus nab-paclitaxel is superior to chemotherapy alone in the management of unresectable stage III/IV pancreatic cancer: a retrospective real-world study

Background

Pancreatic cancer (PC) is widely recognized as one of the most malignant forms of cancer worldwide. Monotherapy with immune checkpoint inhibitors (ICI) has shown limited efficacy in treating this disease. There was controversy surrounding whether combining ICI with chemotherapy provided superior outcomes compared to chemotherapy alone.

Methods

In this study, patients diagnosed with unresectable stage III/IV pancreatic cancer (PC) were classified as receiving programmed cell death protein 1 (PD-1) blockade plus gemcitabine and nab-paclitaxel (AG regimen) (PD-1/chemo, n=27, 50.9%) or chemotherapy alone (chemo, n=26, 49.1%) arm. The primary study endpoints included progression-free survival (PFS) and overall survival (OS), with an additional assessment of treatment-related adverse events graded as three or higher. Chi-square (χ2) statistics were employed to analyze the clinical differences between the two groups, while Kaplan-Meier curves were used to assess the difference in PFS and OS. Statistical significance was defined as P-values less than 0.05 (P < 0.05).

Results

The median follow-up duration was 22 months (range 1-28 months). In the PD-1/chemo arm, the median PFS was eight months, whereas it was 3.5 months in the chemo arm (HR=0.459, 95% CI: 0.252-0.846, P=0.002). Furthermore, the median OS was 15 months in the PD-1/chemo arm and eight months in the chemo arm (HR=0.345, 95% CI: 0.183-0.653, P<0.001). Within the PD-1/chemo arm, 15 (55.6%) patients experienced grade 3 treatment-related adverse events, compared to 13 (50.0%) patients in the chemo arm.

Conclusions

PD-1 blockade combined with nab-paclitaxel plus gemcitabine demonstrated superior efficacy to chemotherapy alone for unresectable stage III/IV PC patients. Future studies were warranted to identify immunosensitive patient subgroups within the PC population, ultimately leading to the development of more efficacious therapeutic strategies.

Clinical Updates for Gastrointestinal Malignancies

Gastrointestinal (GI) cancers include hepatobiliary tumors, pancreatic cancer (PC), neuroendocrine tumors of the gastrointestinal tract, small bowel carcinomas, gastric cancer (GC), anal canal cancer, primary gastric and intestinal lymphomas, gastrointestinal stromal tumors (GISTs) and the most frequent colorectal cancer (CRC) [...].