The Significance of Circulating Tumor Cells in Pancreatic Cancer.

The notion that technically resectable pancreatic ductal adenocarcinoma presents as localized disease is now known to be inaccurate. Evidence supports that most patients have subclinical systemic dissemination at the time of diagnosis. It is now widely accepted that both a local and systemic component of disease coexist, each requiring treatment of improved survival and potential cure. The advent of multiagent chemotherapy regimens has resulted in a modest improvement in survival. Consequently, this article will emphasize the expanding potential and significance of circulating tumor cells in the prognostication and management of patients with pancreatic cancer.

Serplulimab combined with gemcitabine, nab-paclitaxel and stereotactic body radiotherapy as the first-line treatment for patients with metastatic pancreatic adenocarcinoma in China: a multicentre, single-arm, phase II trial (ICSBR) protocol.

INTRODUCTION: Patients with pancreatic ductal adenocarcinoma (PDAC) remain a poor prognosis despite the development of chemotherapy. Although programmed cell death 1 (PD-1) blockade has shown great efficacy in various solid tumours, its application in treating PDAC is limited. Recent studies have indicated that chemotherapy or stereotactic body radiotherapy (SBRT) may improve the antitumour effect of PD-1 blockade in patients with PDAC. The objective of this study is to evaluate the efficacy and safety of combined therapy comprising PD-1 blockade, gemcitabine plus nab-paclitaxel chemotherapy and SBRT for patients with metastatic PDAC. METHODS AND ANALYSIS: This is a multicentre, single-arm, prospective phase II clinical trial. Forty-three patients diagnosed with metastatic PDAC will be enrolled. The eligible patients will be intravenously administered 1000 mg/m2 gemcitabine and 125 mg/m2 nab-paclitaxel on days 1 and 8 of the 21-day cycle. Serplulimab (200 mg) will be administered intravenously on day 1 of the 21-day cycle. Furthermore, during the second cycle, the patients will undergo SBRT with doses of 33 Gy in five fractions for primary lesions or doses of 24 Gy in three fractions for metastases. The primary endpoint is the 6-month progression-free survival (PFS) rate. The secondary endpoints overall survival, PFS, overall response rate, disease control rate, time to progression, duration of response, duration of disease control and safety. Moreover, this trial seeks to investigate biomarkers such as circulating tumour DNA and circulating hybrid cells in patients diagnosed with metastatic PDAC. ETHICS AND DISSEMINATION: The study was approved by the Ethics Committee on Biomedical Research, West China Hospital of Sichuan University. The study results will be presented at international conferences and published in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: ChiCTR2300073237.

Intratumoral NKT cell accumulation promotes antitumor immunity in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDA) is a potentially lethal disease lacking effective treatments. Its immunosuppressive tumor microenvironment (TME) allows it to evade host immunosurveillance and limits response to immunotherapy. Here, using the mouse KRT19-deficient (sgKRT19-edited) PDA model, we find that intratumoral accumulation of natural killer T (NKT) cells is required to establish an immunologically active TME. Mechanistically, intratumoral NKT cells facilitate type I interferon (IFN) production to initiate an antitumor adaptive immune response, and orchestrate the intratumoral infiltration of T cells, dendritic cells, natural killer cells, and myeloid-derived suppressor cells. At the molecular level, NKT cells promote the production of type I IFN through the interaction of their CD40L with CD40 on myeloid cells. To evaluate the therapeutic potential of these observations, we find that administration of folinic acid to mice bearing PDA increases NKT cells in the TME and improves their response to anti-PD-1 antibody treatment. In conclusion, NKT cells have an essential role in the immune response to mouse PDA and are potential targets for immunotherapy.

Senescent cancer-associated fibroblasts in pancreatic adenocarcinoma restrict CD8+ T cell activation and limit responsiveness to immunotherapy in mice.

Senescent cells within tumors and their stroma exert complex pro- and anti-tumorigenic functions. However, the identities and traits of these cells, and the potential for improving cancer therapy through their targeting, remain poorly characterized. Here, we identify a senescent subset within previously-defined cancer-associated fibroblasts (CAFs) in pancreatic ductal adenocarcinomas (PDAC) and in premalignant lesions in mice and humans. Senescent CAFs isolated from mouse and humans expressed elevated levels of immune-regulatory genes. Depletion of senescent CAFs, either genetically or using the Bcl-2 inhibitor ABT-199 (venetoclax), increased the proportion of activated CD8+ T cells in mouse pancreatic carcinomas, whereas induction of CAF senescence had the opposite effect. Combining ABT-199 with an immune checkpoint therapy regimen significantly reduced mouse tumor burden. These results indicate that senescent CAFs in PDAC stroma limit the numbers of activated cytotoxic CD8+ T cells, and suggest that their targeted elimination through senolytic treatment may enhance immunotherapy.

Extracellular vesicle-packaged lncRNA from cancer-associated fibroblasts promotes immune evasion by downregulating HLA-A in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is characterised by immune evasion that contribute to poor prognosis. Cancer-associated fibroblasts (CAFs) play a pivotal role in orchestrating the PDAC tumour microenvironment. We investigated the role of CAF-derived extracellular vesicle (EV)-packaged long non-coding RNAs (lncRNAs) in immune evasion and explored gene therapy using engineered EVs loading small interfering RNAs (siRNAs) as a potential therapeutic strategy. Our findings highlight the significance of EV-packaged lncRNA RP11-161H23.5 from CAF in promoting PDAC immune evasion by downregulating HLA-A expression, a key component of antigen presentation. Mechanistically, RP11-161H23.5 forms a complex with CNOT4, a subunit of the mRNA deadenylase CCR4-NOT complex, enhancing the degradation of HLA-A mRNA by shortening its poly(A) tail. This immune evasion mechanism compromises the anti-tumour immune response. To combat this, we propose an innovative approach utilising engineered EVs as natural and biocompatible nanocarriers for siRNA-based gene therapy and this strategy holds promise for enhancing the effectiveness of immunotherapy in PDAC. Overall, our study sheds light on the critical role of CAF-derived EV-packaged lncRNA RP11-161H23.5/CNOT4/HLA-A axis in PDAC immune evasion and presents a novel avenue for therapeutic intervention.

New Frontiers in Pancreatic Cancer Management: Current Treatment Options and the Emerging Role of Neoadjuvant Therapy.

Pancreatic ductal adenocarcinoma (PDAC) ranks among the 15 most prevalent cancers globally, characterized by aggressive growth and late-stage diagnosis. Advances in imaging and surgical techniques have redefined the classification of pancreatic PDAC into resectable, borderline resectable, and locally advanced pancreatic cancer. While surgery remains the most effective treatment, only 20% of patients are eligible at diagnosis, necessitating innovative strategies to improve outcomes. Therefore, traditional treatment paradigms, primarily surgical resection for eligible patients, are increasingly supplemented by neoadjuvant therapies (NAT), which include chemotherapy, radiotherapy, or a combination of both. By administering systemic therapy prior to surgery, NAT aims to reduce tumor size and increase the feasibility of complete surgical resection, thus enhancing overall survival rates and potentially allowing more patients to undergo curative surgeries. Recent advances in treatment protocols, such as FOLFIRINOX and gemcitabine-nab-paclitaxel, now integral to NAT strategies, have shown promising results in increasing the proportion of patients eligible for surgery by effectively reducing tumor size and addressing micrometastatic disease. Additionally, they offer improved response rates and survival benefits compared to traditional regimes. Despite these advancements, the role of NAT continues to evolve, necessitating ongoing research to optimize treatment regimens, minimize adverse effects, and identify patient populations that would benefit most from these approaches. Through a detailed analysis of current literature and recent clinical trials, this review highlights the transformative potential of NAT in managing PDAC, especially in patients with borderline resectable or locally advanced stages, promising a shift towards more personalized and effective management strategies for PDAC.

Development of human pancreatic cancer avatars as a model for dynamic immune landscape profiling and personalized therapy.

Pancreatic ductal adenocarcinoma (PDAC) is the most common form of pancreatic cancer, a disease with dismal overall survival. Advances in treatment are hindered by a lack of preclinical models. Here, we show how a personalized organotypic "avatar" created from resected tissue allows spatial and temporal reporting on a complete in situ tumor microenvironment and mirrors clinical responses. Our perfusion culture method extends tumor slice viability, maintaining stable tumor content, metabolism, stromal composition, and immune cell populations for 12 days. Using multiplexed immunofluorescence and spatial transcriptomics, we identify immune neighborhoods and potential for immunotherapy. We used avatars to assess the impact of a preclinically validated metabolic therapy and show recovery of stromal and immune phenotypes and tumor redifferentiation. To determine clinical relevance, we monitored avatar response to gemcitabine treatment and identify a patient avatar-predictable response from clinical follow-up. Thus, avatars provide valuable information for syngeneic testing of therapeutics and a truly personalized therapeutic assessment platform for patients.

Unraveling the gut microbiome's contribution to pancreatic ductal adenocarcinoma: mechanistic insights and therapeutic perspectives.

The gut microbiome plays a significant role in the pathogenesis of pancreatic ductal adenocarcinoma (PDAC), influencing oncogenesis, immune responses, and treatment outcomes. Studies have identified microbial species like Porphyromonas gingivalis and Fusobacterium nucleatum, that promote PDAC progression through various mechanisms. Additionally, the gut microbiome affects immune cell activation and response to immunotherapy, including immune checkpoint inhibitors and CAR-T therapy. Specific microbes and their metabolites play a significant role in the effectiveness of immune checkpoint inhibitors (ICIs). Alterations in the gut microbiome can either enhance or diminish responses to PD-1/PD-L1 and CTLA-4 blockade therapy. Additionally, bacterial metabolites like trimethylamine N-oxide (TMAO) and lipopolysaccharide (LPS) impact antitumor immunity, offering potential targets to augment immunotherapy responses. Modulating the microbiome through fecal microbiota transplantation, probiotics, prebiotics, dietary changes, and antibiotics shows promise in PDAC treatment, although outcomes are highly variable. Dietary modifications, particularly high-fiber diets and specific fat consumption, influence microbiome composition and impact cancer risk. Combining microbiome-based therapies with existing treatments holds potential for improving PDAC therapy outcomes, but further research is needed to optimize their effectiveness.

Prognostic impact of the distance from the anterior surface to tumor cells in pancreatoduodenectomy with neoadjuvant chemoradiotherapy for pancreatic ductal adenocarcinoma.

PURPOSE: Several reports have shown the importance of margins in pancreatoduodenectomy (PD) specimens; however, whether anterior surfaces are included as margins varies among reports. In this study, we aimed to examine the impact of the anterior surface on disease-free survival (DFS) and overall survival (OS). METHOD: In total, 98 patients who underwent PD after chemoradiotherapy for pancreatic ductal adenocarcinoma at Mie University Hospital between January 1, 2012, and December 31, 2019, were included. We investigated the prognostic impact of the distance from the anterior surface to tumor cells on DFS and OS using a log-rank test. Multivariate analysis was performed using Cox proportional hazards analysis. RESULTS: A significant difference in DFS and OS was observed up to a distance of 5 mm from the anterior surface of tumor cells. The multivariate analysis revealed that the distance from the anterior surface to tumor cells (≤5 mm) was an independent poor prognostic factor for DFS and OS. CONCLUSION: In patients with PD treated with neoadjuvant therapy, the distance from the anterior surface to tumor cells is an important assessment and should be included in the pathology report.

Proton radiation boosts the efficacy of mesothelin-targeting chimeric antigen receptor T cell therapy in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) represents a challenge in oncology, with limited treatment options for advanced-stage patients. Chimeric antigen receptor T cell (CAR T) therapy targeting mesothelin (MSLN) shows promise, but challenges such as the hostile immunosuppressive tumor microenvironment (TME) hinder its efficacy. This study explores the synergistic potential of combining proton radiation therapy (RT) with MSLN-targeting CAR T therapy in a syngeneic PDAC model. Proton RT significantly increased MSLN expression in tumor cells and caused a significant increase in CAR T cell infiltration into tumors. The combination therapy reshaped the immunosuppressive TME, promoting antitumorigenic M1 polarized macrophages and reducing myeloid-derived suppressor cells (MDSC). In a flank PDAC model, the combination therapy demonstrated superior attenuation of tumor growth and improved survival compared to individual treatments alone. In an orthotopic PDAC model treated with image-guided proton RT, tumor growth was significantly reduced in the combination group compared to the RT treatment alone. Further, the combination therapy induced an abscopal effect in a dual-flank tumor model, with increased serum interferon-γ levels and enhanced proliferation of extratumoral CAR T cells. In conclusion, combining proton RT with MSLN-targeting CAR T therapy proves effective in modulating the TME, enhancing CAR T cell trafficking, and exerting systemic antitumor effects. Thus, this combinatorial approach could present a promising strategy for improving outcomes in unresectable PDAC.

SCANPatient: study protocol for a multi-centre, batched, stepped wedge, comparative effectiveness, randomised clinical trial of synoptic reporting of computerised tomography (CT) scans assessing cancers of the pancreas.

BACKGROUND: Complete surgical removal of pancreatic ductal adenocarcinoma (PDAC) is central to all curative treatment approaches for this aggressive disease, yet this is only possible in patients technically amenable to resection. Hence, an accurate assessment of whether patients are suitable for surgery is of paramount importance. The SCANPatient trial aims to test whether implementing a structured synoptic radiological report results in increased institutional accuracy in defining surgical resectability of non-metastatic PDAC. METHODS: SCANPatient is a batched, stepped wedge, comparative effectiveness, cluster randomised clinical trial. The trial will be conducted at 33 Australian hospitals all of which hold regular multi-disciplinary team meetings (MDMs) to discuss newly diagnosed patients with PDAC. Each site is required to manage a minimum of 20 patients per year (across all stages). Hospitals will be randomised to begin synoptic reporting within a batched, stepped wedge design. Initially all hospitals will continue to use their current reporting method; within each batch, after each 6-month period, a randomly selected group of hospitals will commence using the synoptic reports, until all hospitals are using synoptic reporting. Each hospital will provide data from patients who (i) are aged 18 or older; (ii) have suspected PDAC and have an abdominal CT scan, and (iii) are presented at a participating MDM. Non-metastatic patients will be documented as one of the following categories: (1) locally advanced and surgically unresectable; (2) borderline resectable; or (3) anatomically clearly resectable (Note: Metastatic disease is treated as a separate category). Data collection will last for 36 months in each batch, and a total of 2400 patients will be included. DISCUSSION: Better classifying patients with non-metastatic PDAC as having tumours that are either clearly resectable, borderline or locally advanced and unresectable may improve patient outcomes by optimising care and treatment planning. The borderline resectable group are a small but important cohort in whom surgery with curative intent may be considered; however, inconsistencies with definitions and an understanding of resectability status means these patients are often incorrectly classified and hence overlooked for curative options. TRIAL REGISTRATION: The SCANPatient trial was registered on 17th May 2023 in the Australian New Zealand Clinical Trials Registry (ANZCTR) (ACTRN12623000508673).

Audit of an in-patient palliative care quality improvement process for patients with pancreatic ductal adenocarcinoma in a South African teaching hospital.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with poor survival rates. Timeously introduced palliative care (PC) improves the quality of life (QoL) for patients with terminal diseases. In 2020, an in-patient PC-quality improvement (QI) programme was implemented for PDAC patients. This study compared PC outcomes before and after the introduction of the PC-QI programme. METHODS: A focus group identified five critical intervention areas that could improve care. These were in-patient PC referral, pain and symptom control, shared decision-making, interdisciplinary collaborative care, and continuity of care. A hospital record audit of PDAC patients was conducted in pre- and post-implementation cohorts, and the results were compared. RESULTS: A total of 68 (2017 pre-PC-QI) and 39 (2022 post-PC-QI) patient records were audited. Demography, symptom duration, referral delay, and clinical findings were similar in both cohorts. In-patient PC referrals improved significantly from 54.4% in 2017 to 82.1% in 2022 (p = 0.0059). Significant improvements were also recorded in shared decisionmaking, collaboration, and continuity of care, while the reassessment of pain and symptoms after treatment improved. Fewer invasive procedures were done in the 2022 cohort (p = 0.0056). The delay from admission to an invasive diagnostic procedure decreased from a mean of 8.7 to 1.5 days (p = 0.0001). The duration of hospital admission, overall survival (OS), and readmissions during the final 30 days of life were similar. CONCLUSION: The QI programme resulted in improved use of the in-hospital PC service and made better use of scarce resources. Increasing patient and family participation and feedback will further inform the development of the quality of PC services.

Manipulating regulatory T cells: is it the key to unlocking effective immunotherapy for pancreatic ductal adenocarcinoma?

The five-year survival rates for pancreatic ductal adenocarcinoma (PDAC) have scarcely improved over the last half-century. It is inherently resistant to FDA-approved immunotherapies, which have transformed the outlook for patients with other advanced solid tumours. Accumulating evidence relates this resistance to its hallmark immunosuppressive milieu, which instils progressive dysfunction among tumour-infiltrating effector T cells. This milieu is established at the inception of neoplasia by immunosuppressive cellular populations, including regulatory T cells (Tregs), which accumulate in parallel with the progression to malignant PDAC. Thus, the therapeutic manipulation of Tregs has captured significant scientific and commercial attention, bolstered by the discovery that an abundance of tumour-infiltrating Tregs correlates with a poor prognosis in PDAC patients. Herein, we propose a mechanism for the resistance of PDAC to anti-PD-1 and CTLA-4 immunotherapies and re-assess the rationale for pursuing Treg-targeted therapies in light of recent studies that profiled the immune landscape of patient-derived tumour samples. We evaluate strategies that are emerging to limit Treg-mediated immunosuppression for the treatment of PDAC, and signpost early-stage trials that provide preliminary evidence of clinical activity. In this context, we find a compelling argument for investment in the ongoing development of Treg-targeted immunotherapies for PDAC.

Power-Doppler-based NH002 microbubble sonoporation with chemotherapy relieves hypoxia and enhances the efficacy of chemotherapy and immunotherapy for pancreatic tumors.

Pancreatic ductal adenocarcinoma (PDAC) poses challenges due to late-stage diagnosis and limited treatment response, often attributed to the hypoxic tumor microenvironment (TME). Sonoporation, combining ultrasound and microbubbles, holds promise for enhancing therapy. However, additional preclinical research utilizing commercially available ultrasound equipment for PDAC treatment while delving into the TME's intricacies is necessary. This study investigated the potential of using a clinically available ultrasound system and phase 2-proven microbubbles to relieve tumor hypoxia and enhance the efficacy of chemotherapy and immunotherapy in a murine PDAC model. This approach enables early PDAC detection and blood-flow-sensitive Power-Doppler sonoporation in combination with chemotherapy. It significantly extended treated mice's median survival compared to chemotherapy alone. Mechanistically, this combination therapy enhanced tumor perfusion and substantially reduced tumor hypoxia (77% and 67%, 1- and 3-days post-treatment). Additionally, cluster of differentiation 8 (CD8) T-cell infiltration increased four-fold afterward. The combined treatment demonstrated a strengthening of the anti-programmed death-ligand 1(αPDL1) therapy against PDAC. Our study illustrates the feasibility of using a clinically available ultrasound system with NH-002 microbubbles for early tumor detection, alleviating hypoxic TME, and improving chemotherapy and immunotherapy. It suggests the development of an adjuvant theragnostic protocol incorporating Power-Doppler sonoporation for pancreatic tumor treatment.

Biomarker screen for efficacy of oncolytic virotherapy in patient-derived pancreatic cancer cultures.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a tumour entity with unmet medical need. To assess the therapeutic potential of oncolytic virotherapy (OVT) against PDAC, different oncolytic viruses (OVs) are currently investigated in clinical trials. However, systematic comparisons of these different OVs in terms of efficacy against PDAC and biomarkers predicting therapeutic response are lacking. METHODS: We screened fourteen patient-derived PDAC cultures which reflect the intra- and intertumoural heterogeneity of PDAC for their sensitivity to five clinically relevant OVs, namely serotype 5 adenovirus Ad5-hTERT, herpes virus T-VEC, measles vaccine strain MV-NIS, reovirus jin-3, and protoparvovirus H-1PV. Live cell analysis, quantification of viral genome/gene expression, cell viability as well as cytotoxicity assays and titration of viral progeny were conducted. Transcriptome profiling was employed to identify potential predictive biomarkers for response to OV treatment. FINDINGS: Patient-derived PDAC cultures showed individual response patterns to OV treatment. Twelve of fourteen cultures were responsive to at least one OV, with no single OV proving superior or inferior across all cultures. Known host factors for distinct viruses were retrieved as potential biomarkers. Compared to the classical molecular subtype, the quasi-mesenchymal or basal-like subtype of PDAC was found to be more sensitive to H-1PV, jin-3, and T-VEC. Generally, expression of viral entry receptors did not correlate with sensitivity to OV treatment, with one exception: Expression of Galectin-1 (LGALS1), a factor involved in H-1PV entry, positively correlated with H-1PV induced cell killing. Rather, cellular pathways controlling immunological, metabolic and proliferative signaling appeared to determine outcome. For instance, high baseline expression of interferon-stimulated genes (ISGs) correlated with relative resistance to oncolytic measles virus, whereas low cyclic GMP-AMP synthase (cGAS) expression was associated with exceptional response. Combination treatment of MV-NIS with a cGAS inhibitor improved tumour cell killing in several PDAC cultures and cells overexpressing cGAS were found to be less sensitive to MV oncolysis. INTERPRETATION: Considering the heterogeneity of PDAC and the complexity of biological therapies such as OVs, no single biomarker can explain the spectrum of response patterns. For selection of a particular OV, PDAC molecular subtype, ISG expression as well as activation of distinct signaling and metabolic pathways should be considered. Combination therapies can overcome resistance in specific constellations. Overall, oncolytic virotherapy is a viable treatment option for PDAC, which warrants further development. This study highlights the need for personalised treatment in OVT. By providing all primary data, this study provides a rich source and guidance for ongoing developments. FUNDING: German National Science Foundation (Deutsche Forschungsgemeinschaft, DFG), German Cancer Aid (Deutsche Krebshilfe), German National Academic Scholarship Foundation (Studienstiftung des deutschen Volkes), Survival with Pancreatic Cancer Foundation.

Hereditary Cancer Clinics Improve Adherence to NCCN Germline Testing Guidelines for Pancreatic Cancer.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis, with a 5-year overall survival rate of 10%. In November 2018, NCCN recommended that all patients with PDAC receive genetic counseling (GC) and germline testing regardless of family history. We hypothesized that patients with PDAC were more likely to be referred for testing after this change to the guidelines, regardless of presumed predictive factors, and that compliance would be further improved following the implementation of a hereditary cancer clinic (HCC). METHODS: We conducted a single-institution retrospective analysis of patients diagnosed with PDAC from June 2017 through December 2021 at University of California, Irvine. We compared rates of genetics referral among patients in different diagnostic eras: the 18-month period before the NCCN Guideline change (pre-NCCN era: June 2017 through November 2018), 14 months following the change (post-NCCN era: December 2018 through January 2020), and 18 months after the creation of an HCC (HCC era: June 2020 through December 2021). Family and personal cancer history, genetics referral patterns, and results of GC were recorded. Data were compared using chi-square, Fisher exact, and multivariate analyses. RESULTS: A total of 335 patients were treated for PDAC (123 pre-NCCN, 109 post-NCCN, and 103 HCC) at University of California, Irvine. Demographics across groups were comparable. Prior to the guideline changes, 30% were referred to GC compared with 54.7% in the post-NCCN era. After the implementation of the HCC, 77.4% were referred to GC (P<.0001). The odds ratio (OR) for referral to GC among patients with a positive family history of cancer progressively decreased following the change (pre-NCCN era: OR, 11.90 [95% CI, 3.00-80.14]; post-NCCN era: OR, 3.39 [95% CI, 1.13-10.76]; HCC era: OR, 3.11 [95% CI, 0.95-10.16]). CONCLUSIONS: The 2018 updates to the NCCN Guidelines for PDAC recommending germline testing for all patients with PDAC significantly increased GC referral rates at our academic medical center. Implementation of an HCC further boosted compliance with guidelines.

Triple Blockade of Oncogenic RAS Signaling Using KRAS and MEK Inhibitors in Combination with Irradiation in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest of human malignancies and carries an exceptionally poor prognosis. It is mostly driven by multiple oncogenic alterations, with the highest mutation frequency being observed in the KRAS gene, which is a key oncogenic driver of tumorogenesis and malignant progression in PDAC. However, KRAS remained undruggable for decades until the emergence of G12C mutation specific KRAS inhibitors. Despite this development, this therapeutic approach to target KRAS directly is not routinely used for PDAC patients, with the reasons being the rare presence of G12C mutation in PDAC with only 1-2% of occurring cases, modest therapeutic efficacy, activation of compensatory pathways leading to cell resistance, and absence of effective KRASG12D or pan-KRAS inhibitors. Additionally, indirect approaches to targeting KRAS through upstream and downstream regulators or effectors were also found to be either ineffective or known to cause major toxicities. For this reason, new and more effective treatment strategies that combine different therapeutic modalities aiming at achieving synergism and minimizing intrinsic or adaptive resistance mechanisms are required. In the current work presented here, pancreatic cancer cell lines with oncogenic KRAS G12C, G12D, or wild-type KRAS were treated with specific KRAS or SOS1/2 inhibitors, and therapeutic synergisms with concomitant MEK inhibition and irradiation were systematically evaluated by means of cell viability, 2D-clonogenic, 3D-anchorage independent soft agar, and bioluminescent ATP assays. Underlying pathophysiological mechanisms were examined by using Western blot analyses, apoptosis assay, and RAS activation assay.

Type I conventional dendritic cells facilitate immunotherapy in pancreatic cancer.

Inflammation and tissue damage associated with pancreatitis can precede or occur concurrently with pancreatic ductal adenocarcinoma (PDAC). We demonstrate that in PDAC coupled with pancreatitis (ptPDAC), antigen-presenting type I conventional dendritic cells (cDC1s) are specifically activated. Immune checkpoint blockade therapy (iCBT) leads to cytotoxic CD8+ T cell activation and elimination of ptPDAC with restoration of life span even upon PDAC rechallenge. Using PDAC antigen-loaded cDC1s as a vaccine, immunotherapy-resistant PDAC was rendered sensitive to iCBT with elimination of tumors. cDC1 vaccination coupled with iCBT identified specific CDR3 sequences in the tumor-infiltrating CD8+ T cells with potential therapeutic importance. This study identifies a fundamental difference in the immune microenvironment in PDAC concurrent with, or without, pancreatitis and provides a rationale for combining cDC1 vaccination with iCBT as a potential treatment option.

Identified γ-glutamyl cyclotransferase (GGCT) as a novel regulator in the progression and immunotherapy of pancreatic ductal adenocarcinoma through multi-omics analysis and experiments.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is renowned for its formidable and lethal nature, earning it a notorious reputation among malignant tumors. Due to its challenging early diagnosis, high malignancy, and resistance to chemotherapy drugs, the treatment of pancreatic cancer has long been exceedingly difficult in the realm of oncology. γ-Glutamyl cyclotransferase (GGCT), a vital enzyme in glutathione metabolism, has been implicated in the proliferation and progression of several tumor types, while the biological function of GGCT in pancreatic ductal adenocarcinoma remains unknown. METHODS: The expression profile of GGCT was validated through western blotting, immunohistochemistry, and RT-qPCR in both pancreatic cancer tissue samples and cell lines. Functional enrichment analyses including GSVA, ssGSEA, GO, and KEGG were conducted to explore the biological role of GGCT. Additionally, CCK8, Edu, colony formation, migration, and invasion assays were employed to evaluate the impact of GGCT on the proliferation and migration abilities of pancreatic cancer cells. Furthermore, the LASSO machine learning algorithm was utilized to develop a prognostic model associated with GGCT. RESULTS: Our study revealed heightened expression of GGCT in pancreatic cancer tissues and cells, suggesting an association with poorer patient prognosis. Additionally, we explored the immunomodulatory effects of GGCT in both pan-cancer and pancreatic cancer contexts, found that GGCT may be associated with immunosuppressive regulation in various types of tumors. Specifically, in patients with high expression of GGCT in pancreatic cancer, there is a reduction in the infiltration of various immune cells, leading to poorer responsiveness to immunotherapy and worse survival rates. In vivo and in vitro assays indicate that downregulation of GGCT markedly suppresses the proliferation and metastasis of pancreatic cancer cells. Moreover, this inhibitory effect appears to be linked to the regulation of GGCT on c-Myc. A prognostic model was constructed based on genes derived from GGCT, demonstrating robust predictive ability for favorable survival prognosis and response to immunotherapy.

CAFs-Associated Genes (CAFGs) in Pancreatic Ductal Adenocarcinoma (PDAC) and Novel Therapeutic Strategy.

Pancreatic ductal adenocarcinoma (PDAC) is the most aggressive cancer with striking fibrosis, and its mortality rate is ranked second across human cancers. Cancer-associated fibroblasts (CAFs) play a critical role in PDAC progression, and we reviewed the molecular understanding of PDAC CAFs and novel therapeutic potential at present. CAFs-associated genes (CAFGs) were tentatively classified into three categories by stroma specificity representing stroma/epithelia expression ratios (SE ratios). The recent classification using single cell transcriptome technology clarified that CAFs were composed of myofibroblasts (myCAFs), inflammatory CAFs (iCAFs), and other minor ones (e.g., POSTN-CAFs and antigen presenting CAFs, apCAFs). LRRC15 is a myCAFs marker, and myCAFs depletion by diphtheria toxin induces the rapid accumulation of cytotoxic T lymphocytes (CTLs) and therefore augment PDL1 antibody treatments. This finding proposes that myCAFs may be a critical regulator of tumor immunity in terms of PDAC progression. myCAFs are located in CAFs adjacent to tumor cells, while iCAFs marked by PDPN and/or COL14A1 are distant from tumor cells, where hypoxic and acidic environments being located in iCAFs putatively due to poor blood supply is consistent with HIF1A and GPR68 expressions. iCAFs may be shared with SASP (secretion-associated phenotypes) in senescent CAFs. myCAFs are classically characterized by CAFGs induced by TGFB1, while chemoresistant CAFs with SASP may dependent on IL6 expression and accompanied by STAT3 activation. Recently, it was found that the unique metabolism of CAFs can be targeted to prevent PDAC progression, where PDAC cells utilize glucose, whereas CAFs in turn utilize lactate, which may be epigenetically regulated, mediated by its target genes including CXCR4. In summary, CAFs have unique molecular characteristics, which have been rigorously clarified as novel therapeutic targets of PDAC progression.