Personalized pancreatic cancer therapy: from the perspective of mRNA vaccine

mRNA vaccine development and applications: A special focus on tumors (Review)

Cancer is characterized by unlimited proliferation and metastasis, and traditional therapeutic strategies usually result in the acquisition of drug resistance, thus highlighting the need for more personalized treatment. mRNA vaccines transfer the gene sequences of exogenous target antigens into human cells through transcription and translation to stimulate the body to produce specific immune responses against the encoded proteins, so as to enable the body to obtain immune protection against said antigens; this approach may be adopted for personalized cancer therapy. Since the recent coronavirus pandemic, the development of mRNA vaccines has seen substantial progress and widespread adoption. In the present review, the development of mRNA vaccines, their mechanisms of action, factors influencing their function and the current clinical applications of the vaccine are discussed. A focus is placed on the application of mRNA vaccines in cancer, with the aim of highlighting unique advances and the remaining challenges of this novel and promising therapeutic approach.

Inhibition of Nogo-B reduces the progression of pancreatic cancer by regulation NF-κB/GLUT1 and SREBP1 pathways

Pancreatic cancer (PC) is a lethal disease and associated with metabolism dysregulation. Nogo-B is related to multiple metabolic related diseases and types of cancers. However, the role of Nogo-B in PC remains unknown. In vitro, we showed that cell viability and migration was largely reduced in Nogo-B knockout or knockdown cells, while enhanced by Nogo-B overexpression. Consistently, orthotopic tumor and metastasis was reduced in global Nogo knockout mice. Furthermore, we indicated that glucose enhanced cell proliferation was associated to the elevation expression of Nogo-B and nuclear factor κB (NF-κB). While, NF-κB, glucose transporter type 1 (GLUT1) and sterol regulatory element-binding protein 1 (SREBP1) expression was reduced in Nogo-B deficiency cells. In addition, we showed that GLUT1 and SREBP1 was downstream target of NF-κB. Therefore, we demonstrated that Nogo deficiency inhibited PC progression is regulated by the NF-κB/GLUT1 and SREBP1 pathways, and suggested that Nogo-B may be a target for PC therapy.

Frontiers and future of immunotherapy for pancreatic cancer: from molecular mechanisms to clinical application

Pancreatic cancer is a highly aggressive malignant tumor, that is becoming increasingly common in recent years. Despite advances in intensive treatment modalities including surgery, radiotherapy, biological therapy, and targeted therapy, the overall survival rate has not significantly improved in patients with pancreatic cancer. This may be attributed to the insidious onset, unknown pathophysiology, and poor prognosis of the disease. It is therefore essential to identify and develop more effective and safer treatments for pancreatic cancer. Tumor immunotherapy is the new and fourth pillar of anti-tumor therapy after surgery, radiotherapy, and chemotherapy. Significant progress has made in the use of immunotherapy for a wide variety of malignant tumors in recent years; a breakthrough has also been made in the treatment of pancreatic cancer. This review describes the advances in immune checkpoint inhibitors, cancer vaccines, adoptive cell therapy, oncolytic virus, and matrix-depletion therapies for the treatment of pancreatic cancer. At the same time, some new potential biomarkers and potential immunotherapy combinations for pancreatic cancer are discussed. The molecular mechanisms of various immunotherapies have also been elucidated, and their clinical applications have been highlighted. The current challenges associated with immunotherapy and proposed strategies that hold promise in overcoming these limitations have also been discussed, with the aim of offering new insights into immunotherapy for pancreatic cancer.

A novel multidrug-resistant cell line from a Chinese patient with pancreatic ductal adenocarcinoma

Chemotherapy resistance poses clinical challenges in pancreatic cancer treatment. Developing cell lines resistant to chemotherapy is crucial for investigating drug resistance mechanisms and identifying alternative treatment pathways. The genetic and biological attributes of pancreatic cancer depend on its aetiology, racial demographics and anatomical origin, underscoring the need for models that comprehensively represent these characteristics. Here, we introduce PDAC-X2, a pancreatic cancer cell line derived from Chinese patients. We conducted a comprehensive analysis encompassing the immune phenotype, biology, genetics, molecular characteristics and tumorigenicity of the cell line. PDAC-X2 cells displayed epithelial morphology and expressed cell markers (CK7 and CK19) alongside other markers (E-cadherin, Vimentin, Ki-67, CEA and CA19-9). The population doubling time averaged around 69 h. In vivo, PDAC-X2 cells consistently maintained their tumorigenicity, achieving a 100% tumour formation rate. Characterised by a predominantly tetraploid karyotype, this cell line exhibited a complex genetic markup. Notably, PDAC-X2 cells demonstrated resistance to multiple drugs, including gemcitabine, paclitaxel, 5-fluorouracil and oxaliplatin. In conclusion, PDAC-X2 presents an invaluable preclinical model. Its utility lies in facilitating the study of drug resistance mechanisms and the exploration of alternative therapeutic approaches aimed at enhancing the prognosis of this tumour type.

New avenues for the treatment of immunotherapy-resistant pancreatic cancer

Pancreatic cancer (PC) is characterized by its extremely aggressive nature and ranks 14th in the number of new cancer cases worldwide. However, due to its complexity, it ranks 7th in the list of the most lethal cancers worldwide. The pathogenesis of PC involves several complex processes, including familial genetic factors associated with risk factors such as obesity, diabetes mellitus, chronic pancreatitis, and smoking. Mutations in genes such as KRAS, TP53, and SMAD4 are linked to the appearance of malignant cells that generate pancreatic lesions and, consequently, cancer. In this context, some therapies are used for PC, one of which is immunotherapy, which is extremely promising in various other types of cancer but has shown little response in the treatment of PC due to various resistance mechanisms that contribute to a drop in immunotherapy efficiency. It is therefore clear that the tumor microenvironment (TME) has a huge impact on the resistance process, since cellular and non-cellular elements create an immunosuppressive environment, characterized by a dense desmoplastic stroma with cancer-associated fibroblasts, pancreatic stellate cells, extracellular matrix, and immunosuppressive cells. Linked to this are genetic mutations in TP53 and immunosuppressive factors that act on T cells, resulting in a shortage of CD8+ T cells and limited expression of activation markers such as interferon-gamma. In this way, finding new strategies that make it possible to manipulate resistance mechanisms is necessary. Thus, techniques such as the use of TME modulators that block receptors and stromal molecules that generate resistance, the use of genetic manipulation in specific regions, such as microRNAs, the modulation of extrinsic and intrinsic factors associated with T cells, and, above all, therapeutic models that combine these modulation techniques constitute the promising future of PC therapy. Thus, this study aims to elucidate the main mechanisms of resistance to immunotherapy in PC and new ways of manipulating this process, resulting in a more efficient therapy for cancer patients and, consequently, a reduction in the lethality of this aggressive cancer.

Illuminating the immunological landscape: mitochondrial gene defects in pancreatic cancer through a multiomics lens

This comprehensive review delves into the complex interplay between mitochondrial gene defects and pancreatic cancer pathogenesis through a multiomics approach. By amalgamating data from genomic, transcriptomic, proteomic, and metabolomic studies, we dissected the mechanisms by which mitochondrial genetic variations dictate cancer progression. Emphasis has been placed on the roles of these genes in altering cellular metabolic processes, signal transduction pathways, and immune system interactions. We further explored how these findings could refine therapeutic interventions, with a particular focus on precision medicine applications. This analysis not only fills pivotal knowledge gaps about mitochondrial anomalies in pancreatic cancer but also paves the way for future investigations into personalized therapy options. This finding underscores the crucial nexus between mitochondrial genetics and oncological immunology, opening new avenues for targeted cancer treatment strategies.

Assessment of the association between D-dimer levels and clinicopathological characteristics of pancreatic cancer and its role in prognosis: A systematic review and meta-analysis

According to previous studies, D-dimer levels are associated with the prognosis of patients with pancreatic cancer (PC). However, the results of current studies are limited and controversial. Therefore, we performed this meta-analysis to assess the relationship between D-dimer levels and prognostic and pathological characteristics of PC patients. We first searched the databases of PubMed, Embase, The Cochrane Library, Web Of Science, CBM, VIP, CNKI and Wanfang to identify available studies. The relationship between pretreatment d-dimer levels and prognosis in PC patients was assessed using the combined hazard ratio (HR) and 95% confidence interval (CI). The combined odds ratio (OR) and 95% confidence interval (CI) were used in assessing the relationship between pathological characteristics and d-dimer levels in PC patients. Stata 12.0 software was used for all statistical analyses. In total, we included 13 studies involving 2777 patients. The results showed that elevated pre-treatment d -dimer levels were significantly associated with OS deterioration (HR = 1.46 95% CI: 1.34-1.59; p < 0.001). We also performed subgroup analyses based on sample size, d -dimer threshold, follow-up time, and HR source to further validate the prognostic value of pretreatment d -dimer levels in PC. In addition, according to the analysis, high pretreatment d -dimer levels in PC patients were associated with late tumor stage (OR = 4.78, 95% CI 1.73-13.20, p < 0. 005), larger tumor size (OR = 1.72, 95% CI 1.25-2.35, p < 0.005), and distant metastasis of tumor (OR = 5.06, 95% CI 2.45-10.43, p < 0.005) were significantly associated. In contrast, other clinicopathological factors, including age, gender and lymph node metastasis, were not associated with d-dimer levels. In conclusion, we found that high pre-treatment d-dimer levels were associated with a poor prognosis in PC patients, in relation to later tumor stage, larger tumor size and the development of distant metastases. Plasma d-dimer levels can be used as a biomarker of prognosis in PC patients.

A novel risk score system based on immune subtypes for identifying optimal mRNA vaccination population in hepatocellular carcinoma

PURPOSE

Although mRNA vaccines have shown certain clinical benefits in multiple malignancies, their therapeutic efficacies against hepatocellular carcinoma (HCC) remains uncertain. This study focused on establishing a novel risk score system based on immune subtypes so as to identify optimal HCC mRNA vaccination population.

METHODS

GEPIA, cBioPortal and TIMER databases were utilized to identify candidate genes for mRNA vaccination in HCC. Subsequently, immune subtypes were constructed based on the candidate genes. According to the differential expressed genes among various immune subtypes, a risk score system was established using machine learning algorithm. Besides, multi-color immunofluorescence of tumor tissues from 72 HCC patients were applied to validate the feasibility and efficiency of the risk score system.

RESULTS

Twelve overexpressed and mutated genes associated with poor survival and APCs infiltration were identified as potential candidate targets for mRNA vaccination. Three immune subtypes (e.g. IS1, IS2 and IS3) with distinct clinicopathological and molecular profiles were constructed according to the 12 candidate genes. Based on the immune subtype, a risk score system was developed, and according to the risk score from low to high, HCC patients were classified into four subgroups on average (e.g. RS1, RS2, RS3 and RS4). RS4 mainly overlapped with IS3, RS1 with IS2, and RS2+RS3 with IS1. ROC analysis also suggested the significant capacity of the risk score to distinguish between the three immune subtypes. Higher risk score exhibited robustly predictive ability for worse survival, which was further independently proved by multi-color immunofluorescence of HCC samples. Notably, RS4 tumors exhibited an increased immunosuppressive phenotype, higher expression of the twelve potential candidate targets and increased genome altered fraction, and therefore might benefit more from vaccination.

CONCLUSIONS

This novel risk score system based on immune subtypes enabled the identification of RS4 tumor that, due to its highly immunosuppressive microenvironment, may benefit from HCC mRNA vaccination.

Pancreatic cancer tumor microenvironment is a major therapeutic barrier and target

Pancreatic Ductal Adenocarcinoma (PDAC) is projected to become the 2nd leading cause of cancer-related deaths in the United States. Limitations in early detection and treatment barriers contribute to the lack of substantial success in the treatment of this challenging-to-treat malignancy. Desmoplasia is the hallmark of PDAC microenvironment that creates a physical and immunologic barrier. Stromal support cells and immunomodulatory cells face aberrant signaling by pancreatic cancer cells that shifts the complex balance of proper repair mechanisms into a state of dysregulation. The product of this dysregulation is the desmoplastic environment that encases the malignant cells leading to a dense, hypoxic environment that promotes further tumorigenesis, provides innate systemic resistance, and suppresses anti-tumor immune invasion. This desmoplastic environment combined with the immunoregulatory events that allow it to persist serve as the primary focus of this review. The physical barrier and immune counterbalance in the tumor microenvironment (TME) make PDAC an immunologically cold tumor. To convert PDAC into an immunologically hot tumor, tumor microenvironment could be considered alongside the tumor cells. We discuss the complex network of microenvironment molecular and cellular composition and explore how they can be targeted to overcome immuno-therapeutic challenges.

Tumor immune microenvironment-based therapies in pancreatic ductal adenocarcinoma: time to update the concept

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal solid tumors. The tumor immune microenvironment (TIME) formed by interactions among cancer cells, immune cells, cancer-associated fibroblasts (CAF), and extracellular matrix (ECM) components drives PDAC in a more immunosuppressive direction: this is a major cause of therapy resistance and poor prognosis. In recent years, research has advanced our understanding of the signaling mechanism by which TIME components interact with the tumor and the evolution of immunophenotyping. Through revolutionary technologies such as single-cell sequencing, we have gone from simply classifying PDACs as "cold" and "hot" to a more comprehensive approach of immunophenotyping that considers all the cells and matrix components. This is key to improving the clinical efficacy of PDAC treatments. In this review, we elaborate on various TIME components in PDAC, the signaling mechanisms underlying their interactions, and the latest research into PDAC immunophenotyping. A deep understanding of these network interactions will contribute to the effective combination of TIME-based therapeutic approaches, such as immune checkpoint inhibitors (ICI), adoptive cell therapy, therapies targeting myeloid cells, CAF reprogramming, and stromal normalization. By selecting the appropriate integrated therapies based on precise immunophenotyping, significant advances in the future treatment of PDAC are possible.

Innovative Strategies to Enhance mRNA Vaccine Delivery and Effectiveness: Mechanisms and Future Outlook

The creation of mRNA vaccines has transformed the area of vaccination and allowed for the production of COVID-19 vaccines with previously unheard-of speed and effectiveness. The development of novel strategies to enhance the delivery and efficiency of mRNA vaccines has been motivated by the ongoing constraints of the present mRNA vaccine delivery systems. In this context, intriguing methods to get beyond these restrictions include lipid nanoparticles, self-amplifying RNA, electroporation, microneedles, and cell-targeted administration. These innovative methods could increase the effectiveness, safety, and use of mRNA vaccines, making them more efficient, effective, and broadly available. Additionally, mRNA technology may have numerous and far-reaching uses in the field of medicine, opening up fresh avenues for the diagnosis and treatment of disease. This paper gives an overview of the existing drawbacks of mRNA vaccine delivery techniques, the creative solutions created to address these drawbacks, and their prospective public health implications. The development of mRNA vaccines for illnesses other than infectious diseases and creating scalable and affordable manufacturing processes are some of the future directions for research in this area that are covered in this paper.

Celastrol suppresses human pancreatic cancer via m6A-YTHDF3-mediated downregulation of Claspin and Bcl-2

BACKGROUND

Celastrol has been revealed to exhibit anticancer pharmacological activity, however, the molecular mechanisms of celastrol involved in pancreatic cancer remain to be further elucidated. The present study was to illustrate whether celastrol suppresses pancreatic cancer through modulating RNA m6A modification.

METHODS

Effect of celastrol treatment on the malignant phenotypes of pancreatic cancer cells was evaluated by CCK-8 assay, EdU assay, colony formation assay, flow cytometry analysis and subcutaneous xenograft experiments. RNA sequencing (RNA-seq) analysis was carried out to analyze the genes differentially expressed in celastrol-treated pancreatic cancer cells. RT-qPCR, Western blotting and immunohistochemistry were employed to evaluate the expression of the indicated genes. RNA dot blot and quantification of total RNA m6A modification assays, MeRIP-qPCR assay, RIP-qPCR assay, RNA stability and protein stability assays were applied to evaluate the regulatory mechanism of celastrol treatment in pancreatic cancer cells.

RESULTS

We demonstrated that celastrol suppressed cell proliferation and induced cell cycle arrest and apoptosis of pancreatic cancer cells in vitro, and decreased tumor growth in vivo. Specifically, Bcl-2, Claspin, METTL3 and YTHDF3 were identified as the potential targets of celastrol treatment in pancreatic cancer cells. Moreover, our results indicated that celastrol treatment downregulated METTL3 and decreased m6A levels of Claspin and Bcl-2 mRNA, leading to the degradation of Claspin and Bcl-2 mRNA in pancreatic cancer cells. Furthermore, we revealed that celastrol treatment downregulated Claspin and Bcl-2, at least in part, in an m6A-YTHDF3-mediated manner in pancreatic cancer cells.

CONCLUSION

Our study highlighted a novel mechanism underlying celastrol-induced cellular proliferation inhibition and apoptosis in pancreatic cancer cells via m6A-YTHDF3-mediated downregulation of Claspin and Bcl-2.

Unraveling the therapeutic potential of Senna singueana phytochemicals to attenuate pancreatic cancer using protein-protein interactions, molecular docking, and MD simulation

Pancreatic cancer (PC) presents challenges due to limited treatment options and patients seek complementary therapies alongside conventional treatments to improve well-being. This study uses computational drug discovery approaches to find potential phytochemicals from S. singueana for PC treatment. Among the 38 phytochemicals screened from S. singueana, specific inhibitors against PC were selected. Protein-protein interaction (PPI) network analysis highlighted key targets with high degrees, including PTEN (8) and PTK2 (7) genes, along with their respective proteins 5BZX and 3BZ3, which were employed for molecular docking studies. 1-methylchrysene and 3-methyl-1,8,9-anthracenetriol showed strong binding affinities of - 9.2 and - 8.1 Kcal/mol, respectively. Molecular dynamics simulations lasting 300 ns assessed structural stability and interaction energy of compound-target dockings: 1-methylchrysene-PTEN and 3-methyl-1,8,9-anthracenetriol-PTK2. In molecular dynamics simulations, the 3-methyl-1,8,9-anthracenetriol-PTK2 complex showed lower RMSD, RMSF, radius of gyration, solvent-accessible surface area, and more hydrogen bonds than the 1-methylchrysene-PTEN complex. The 3-methyl-1,8,9-anthracenetriol-PTK2 complex exhibited significantly stronger binding with a binding free energy (ΔG) of - 21.92 kcal/mol compared to the less favourable ΔG of - 10.65 kcal/mol for the 1-methylchrysene-PTEN complex. The consistent and stable binding interaction observed in the 3-methyl-1,8,9-anthracenetriol-PTK2 complex highlights its potential as a potent inhibitor of Focal Adhesion Kinase 1. Consequently, it emerges as a promising lead compound for the development of pancreatic cancer therapeutics. Conversely, the fluctuations observed in the 1-methylchrysene-PTEN complex indicate a less stable binding interaction. This indicates the potential of 3-methyl-1,8,9-anthracenetriol as a primary candidate for pancreatic cancer treatment. These findings improve our grasp of S. singueana's multi-target effects and its promise in addressing pancreatic cancer. Nevertheless, additional in-vivo and in-vitro studies are required to validate their effectiveness and therapeutic potential.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-023-00179-9.

Machine learning algorithm integrates bulk and single-cell transcriptome sequencing to reveal immune-related personalized therapy prediction features for pancreatic cancer

Pancreatic cancer (PC) is a digestive malignancy with worse overall survival. Tumor immune environment (TIME) alters the progression and proliferation of various solid tumors. Hence, we aimed to detect the TIME-related classifier to facilitate the personalized treatment of PC. Based on the 1612 immune-related genes (IRGs), we classified patients into Immune_rich and Immune_desert subgroups via consensus clustering. Patients in distinct subtypes exhibited a difference in sensitivity to immune checkpoint blockers (ICB). Next, the immune-related signature (IRS) model was established based on 8 IRGs (SYT12, TNNT1, TRIM46, SMPD3, ANLN, AFF3, CXCL9 and RP1L1) and validated its predictive efficiency in multiple cohorts. RT-qPCR experiments demonstrated the differential expression of 8 IRGs between tumor and normal cell lines. Patients who gained lower IRS score tended to be more sensitive to chemotherapy and immunotherapy, and obtained better overall survival compared to those with higher IRS scores. Moreover, scRNA-seq analysis revealed that fibroblast and ductal cells might affect malignant tumor cells via MIF-(CD74+CD44) and SPP1-CD44 axis. Eventually, we identified eight therapeutic targets and one agent for IRS high patients. Our study screened out the specific regulation pattern of TIME in PC, and shed light on the precise treatment of PC.

Signalling in pancreatic cancer: from pathways to therapy

Pancreatic cancer (PC) is a common malignant tumour in the digestive system. Due to the lack of sensitive diagnostic markers, strong metastasis ability, and resistance to anti-cancer drugs, the prognosis of PC is inferior. In the past decades, increasing evidence has indicated that the development of PC is closely related to various signalling pathways. With the exploration of RAS-driven, epidermal growth factor receptor, Hedgehog, NF-κB, TGF-β, and NOTCH signalling pathways, breakthroughs have been made to explore the mechanism of pancreatic carcinogenesis, as well as the novel therapies. In this review, we discussed the signalling pathways involved in PC and summarised current targeted agents in the treatment of PC. Furthermore, opportunities and challenges in the exploration of potential therapies targeting signalling pathways were also highlighted.

Feasibility of 125I brachytherapy combined with arterial infusion chemotherapy in patients with advanced pancreatic cancer

To evaluation the feasibility of Iodine-125 (¹²5I) brachytherapy combined with arterial infusion chemotherapy in patients with advanced pancreatic cancer. A total of 72 cases with Stage III and IV were retrospectively reviewed. 23 cases receiving 125I brachytherapy were classified as Group A. 27 cases receiving arterial infusion chemotherapy (gemcitabine + cisplatin, GP) were classified as Group B and 22 cases receiving 125I brachytherapy combined with arterial infusion chemotherapy (GP) were classified as Group C. The evaluated indications were local control rate, survival rate, carbohydrate antigen 19-9, pain relief, and Karnofsky physical scores. Analysis of Variancep, Pearson chi-square test and Kaplan-Meier curves were used for analysis. The local control rate of group A and group C was significantly higher than group B (P < .001). Pearson chi-square test showed statistical difference of the 3 groups (χ2 = 12.969, P = .044). The median survival of group A,B and C was 9 months, 6 months and 13 months, respectively. The survival time of group C was significantly higher than group B (χ2 = 5.403, P = .020). The Log rank test showed statistical difference in the survival curve of the 3 groups (χ2 = 6.501, P = .039). The difference of carbohydrate antigen 19-9 decline percentage between group B and C group was statistically significant (χ2 = 5.959, P = .015). Patients in group A and group C relieved form pain after treatment with statistically significant (P < .001). Pain relief was much more effective in patients who received 125I brachytherapy. Karnofsky physical scores after treatment were statistically higher than those before treatment in each group (P < .001). 125I brachytherapy maybe one of the effective, safe and feasible alternative treatment of advanced pancreatic cancer. ¹²5I brachytherapy combined with arterial infusion chemotherapy was effective in the treatment of advanced pancreatic cancer.

mRNA Cancer Vaccines: Construction and Boosting Strategies

In late 2020, the U.S. Food and Drug Administration (FDA) approved a lipid-based mRNA vaccine for the prevention of COVID-19, which has pushed this field to be more closely studied and motivated researchers to delve deeper into mRNA therapeutics. To date, the research on mRNA cancer vaccines has been developed rapidly, and substantial hopeful therapeutic results have been achieved against various solid tumors in clinical trials. In this review, we first introduce three main components of mRNA cancer vaccines, including mRNA antigens, adjuvants, and delivery vectors. Engineering these components can optimize the therapeutic effects of mRNA cancer vaccines. For instance, appropriate modification of mRNA structure can alleviate the poor stability and innate immunogenicity of mRNA, and the use of mRNA delivery vectors can address the issues of low delivery efficiency in vivo. Second, we emphatically discuss some strategies to further improve the efficacy of mRNA cancer vaccines, namely modulating the immunosuppressive tumor environment, optimizing administration routes, achieving targeting delivery to intended tissues or organs, and employing combination therapy. These strategies can strengthen the tumor inhibitory ability of mRNA cancer vaccines and increase the possibility of tumor elimination. Finally, we point out some challenges in the clinical practice of mRNA cancer vaccines and offer our perspectives on future developments in this rapidly evolving field. It is anticipated that mRNA cancer vaccines will be rapidly developed for clinical cancer therapy in the near future.

Developments and challenges in neoadjuvant therapy for locally advanced pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) remains a significant public health challenge and is currently the fourth leading cause of cancer-related mortality in developed countries. Despite advances in cancer treatment, the 5-year survival rate for patients with PDAC remains less than 5%. In recent years, neoadjuvant therapy (NAT) has emerged as a promising treatment option for many cancer types, including locally advanced PDAC, with the potential to improve patient outcomes. To analyze the role of NAT in the setting of locally advanced PDAC over the past decade, a systematic literature search was conducted using PubMed and Web of Science. The results suggest that NAT may reduce the local mass size, promote tumor downstaging, and increase the likelihood of resection. These findings are supported by the latest evidence-based medical literature and the clinical experience of our center. Despite the potential benefits of NAT, there are still challenges that need to be addressed. One such challenge is the lack of consensus on the optimal timing and duration of NAT. Improved criteria for patient selection are needed to further identify PDAC patients likely to respond to NAT. In conclusion, NAT has emerged as a promising treatment option for locally advanced PDAC. However, further research is needed to optimize its use and to better understand the role of NAT in the management of this challenging disease. With continued advances in cancer treatment, there is hope of improving the outcomes of patients with PDAC in the future.

Molecular and metabolic regulation of immunosuppression in metastatic pancreatic ductal adenocarcinoma

Immunosuppression is a hallmark of pancreatic ductal adenocarcinoma (PDAC), contributing to early metastasis and poor patient survival. Compared to the localized tumors, current standard-of-care therapies have failed to improve the survival of patients with metastatic PDAC, that necessecitates exploration of novel therapeutic approaches. While immunotherapies such as immune checkpoint blockade (ICB) and therapeutic vaccines have emerged as promising treatment modalities in certain cancers, limited responses have been achieved in PDAC. Therefore, specific mechanisms regulating the poor response to immunotherapy must be explored. The immunosuppressive microenvironment driven by oncogenic mutations, tumor secretome, non-coding RNAs, and tumor microbiome persists throughout PDAC progression, allowing neoplastic cells to grow locally and metastasize distantly. The metastatic cells escaping the host immune surveillance are unique in molecular, immunological, and metabolic characteristics. Following chemokine and exosomal guidance, these cells metastasize to the organ-specific pre-metastatic niches (PMNs) constituted by local resident cells, stromal fibroblasts, and suppressive immune cells, such as the metastasis-associated macrophages, neutrophils, and myeloid-derived suppressor cells. The metastatic immune microenvironment differs from primary tumors in stromal and immune cell composition, functionality, and metabolism. Thus far, multiple molecular and metabolic pathways, distinct from primary tumors, have been identified that dampen immune effector functions, confounding the immunotherapy response in metastatic PDAC. This review describes major immunoregulatory pathways that contribute to the metastatic progression and limit immunotherapy outcomes in PDAC. Overall, we highlight the therapeutic vulnerabilities attributable to immunosuppressive factors and discuss whether targeting these molecular and immunological "hot spots" could improve the outcomes of PDAC immunotherapies.