SMAD4 gene mutations are associated with poor prognosis in pancreatic cancer

Genome-Wide Characterization of Fennel (Anethum foeniculum) MiRNome and Identification of its Potential Targets in Homo sapiens and Arabidopsis thaliana: An Inter and Intra-species Computational Scrutiny

MicroRNAs could be promising biomarkers for various diseases, and small RNA drugs have already been FDA approved for clinical use. This area of research is rapidly expanding and has significant potential for the future. Fennel (Anethum foeniculum) is a highly esteemed spice plant with economic and medicinal benefits, making it an invaluable asset in the pharmaceutical industry. To characterize the fennel miRNAs and their Arabidopsis thaliana and Homo sapience targets with functional enrichment analysis and human disease association. A homology-based computational approach characterized the MiRnome of the Anethum foeniculum genome and assessed its impact on Arabidopsis thaliana and Homo sapience transcriptomes. In addition, functional enrichment analysis was evaluated for both species' targets. Moreover, PPI network analysis, hub gene identification, and MD simulation analysis of the top hub node with fennel miRNA were incorporated. We have identified 100 miRNAs of fennel and their target genes, which include 2536 genes in Homo sapiens and 1314 genes in Arabidopsis thaliana. Functional enrichment analysis reveals 56 Arabidopsis thaliana targets of fennel miRNAs showed involvement in metabolic pathways. Highly enriched human KEGG pathways were associated with several diseases, especially cancer. The protein-protein interaction network of human targets determined the top ten nodes; from them, seven hub nodes, namely MAPK1, PIK3R1, STAT3, EGFR, KRAS, CDC42, and SMAD4, have shown their involvement in the pancreatic cancer pathway. Based on the Blast algorithm, 21 fennel miRNAs are homologs to 16 human miRNAs were predicted; from them, the CSPP1 target was a common target for afo-miR11117a-3p and has-miR-6880-5p homologs miRNAs. Our results are the first to report the 100 fennel miRNAs, and predictions for their endogenous and human target genes provide a basis for further understanding of Anethum foeniculum miRNAs and the biological processes and diseases with which they are associated.

Clinical and molecular characteristics of patients with brain metastasis secondary to pancreatic ductal adenocarcinoma

BACKGROUND

The prognosis for patients with pancreatic ductal adenocarcinoma (PDAC) is poor. Secondary brain metastasis (Br-M) occurs in less than 1% of patients. Clinical characteristics and molecular alterations have not been characterized in this rare patients' subset.

MATERIALS AND METHODS

The Foundry software platform was used to retrospectively query electronic health records for patients with Br-M secondary to PDAC from 2005 to 2023; clinical, molecular, and overall survival (OS) data were analyzed.

RESULTS

Br-M was diagnosed in 44 patients with PDAC. Median follow-up was 78 months; median OS from initial PDAC diagnosis was 47 months. Median duration from PDAC diagnosis to Br-M detection was 24 months; median OS from Br-M diagnosis was 3 months. At Br-M diagnosis, 82% (n = 36) of patients had elevated CA19-9. Lung was the most common preexisting metastatic location (71%) with Br-M, followed by liver (66%). Br-M were most frequently observed in the frontal lobe (34%, n = 15), cerebellar region (23%, n = 10), and leptomeninges (18%, n = 8). KRAS mutations were detected in 94.1% (n = 16) of patients who had molecular data available (n = 17) with KRASG12V being the most frequent subtype 47% (n = 8); KRASG12D in 29% (n = 5); KRASG12R in 18% (n = 3). Patients who underwent Br-M surgical resection (n = 5) had median OS of 8.6 months, while median OS following stereotactic radiosurgery only (n = 11) or whole-brain radiation only (n = 20) was 3.3 and 2.8 months, respectively.

CONCLUSION

Br-M is a late PDAC complication, resulting in an extremely poor prognosis especially in leptomeningeal disease. KRAS was mutated in 94.1% of the patients and the KRASG12V subtype was prevalent.

A multiplexed time-resolved fluorescence resonance energy transfer ultrahigh-throughput screening assay for targeting the SMAD4-SMAD3-DNA complex

The transforming growth factor-beta (TGFβ) signaling pathway plays crucial roles in the establishment of an immunosuppressive tumor microenvironment, making anti-TGFβ agents a significant area of interest in cancer immunotherapy. However, the clinical translation of current anti-TGFβ agents that target upstream cytokines and receptors remains challenging. Therefore, the development of small-molecule inhibitors specifically targeting SMAD4, the downstream master regulator of the TGFβ pathway, would offer an alternative approach with significant therapeutic potential for anti-TGFβ signaling. In this study, we present the development of a cell lysate-based multiplexed time-resolved fluorescence resonance energy transfer (TR-FRET) assay in an ultrahigh-throughput screening (uHTS) 1536-well plate format. This assay enables simultaneous monitoring of the protein‒protein interaction between SMAD4 and SMAD3, as well as the protein‒DNA interaction between SMADs and their consensus DNA-binding motif. The multiplexed TR-FRET assay exhibits high sensitivity, allowing the dynamic analysis of the SMAD4-SMAD3-DNA complex at single-amino acid resolution. Moreover, the multiplexed uHTS assay demonstrates robustness for screening small-molecule inhibitors. Through a pilot screening of an FDA-approved bioactive compound library, we identified gambogic acid and gambogenic acid as potential hit compounds. These proof-of-concept findings underscore the utility of our optimized multiplexed TR-FRET platform for large-scale screening to discover small-molecule inhibitors that target the SMAD4-SMAD3-DNA complex as novel anti-TGFβ signaling agents.

Metastatic site influences driver gene function in pancreatic cancer

Driver gene mutations can increase the metastatic potential of the primary tumor1-3, but their role in sustaining tumor growth at metastatic sites is poorly understood. A paradigm of such mutations is inactivation of SMAD4 - a transcriptional effector of TGFβ signaling - which is a hallmark of multiple gastrointestinal malignancies4,5. SMAD4 inactivation mediates TGFβ's remarkable anti- to pro-tumorigenic switch during cancer progression and can thus influence both tumor initiation and metastasis6-14. To determine whether metastatic tumors remain dependent on SMAD4 inactivation, we developed a mouse model of pancreatic ductal adenocarcinoma (PDAC) that enables Smad4 depletion in the pre-malignant pancreas and subsequent Smad4 reactivation in established metastases. As expected, Smad4 inactivation facilitated the formation of primary tumors that eventually colonized the liver and lungs. By contrast, Smad4 reactivation in metastatic disease had strikingly opposite effects depending on the tumor's organ of residence: suppression of liver metastases and promotion of lung metastases. Integrative multiomic analysis revealed organ-specific differences in the tumor cells' epigenomic state, whereby the liver and lungs harbored chromatin programs respectively dominated by the KLF and RUNX developmental transcription factors, with Klf4 depletion being sufficient to reverse Smad4's tumor-suppressive activity in liver metastases. Our results show how epigenetic states favored by the organ of residence can influence the function of driver genes in metastatic tumors. This organ-specific gene-chromatin interplay invites consideration of anatomical site in the interpretation of tumor genetics, with implications for the therapeutic targeting of metastatic disease.

Clinical Evaluation of the Pancreatic Cancer Microenvironment: Opportunities and Challenges

Advances in our understanding of pancreatic ductal adenocarcinoma (PDAC) and its tumor microenvironment (TME) have the potential to transform treatment for the hundreds of thousands of patients who are diagnosed each year. Whereas the clinical assessment of cancer cell genetics has grown increasingly sophisticated and personalized, current protocols to evaluate the TME have lagged, despite evidence that the TME can be heterogeneous within and between patients. Here, we outline current protocols for PDAC diagnosis and management, review novel biomarkers, and highlight potential opportunities and challenges when evaluating the PDAC TME as we prepare to translate emerging TME-directed therapies to the clinic.

Combination of mutations in genes controlling DNA repair and high mutational load plays a prognostic role in pancreatic ductal adenocarcinoma (PDAC): a retrospective real-life study in Sardinian population

BACKGROUND

Patients with pancreatic ductal adenocarcinoma (PDCA) carrying impaired mismatch repair mechanisms seem to have an outcome advantage under treatment with conventional chemotherapy, whereas the role for the tumor mutation burden on prognosis is controversial. In this study, we evaluated the prognostic role of the mutated genes involved in genome damage repair in a real-life series of PDAC patients in a hospital-based manner from the main Institution deputed to surgically treat such a disease in North Sardinia.

METHODS

A cohort of fifty-five consecutive PDAC patients with potentially resectable/border line resectable PDAC (stage IIB-III) or oligometastatic disease (stage IV) and tumor tissue availability underwent next-generation sequencing (NGS)-based analysis using a panel containing driver oncogenes and tumor suppressor genes as well as genes controlling DNA repair mechanisms.

RESULTS

Genes involved in the both genome damage repair (DR) and DNA mismatch repair (MMR) were found mutated in 17 (31%) and 15 (27%) cases, respectively. One fourth of PDAC cases (14/55; 25.5%) carried tumors presenting a combination of mutations in repair genes (DR and MMR) and the highest mutation load rates (MLR-H). After correction for confounders (surgery, adjuvant therapy, stage T, and metastasis), multivariate Cox regression analysis indicated that mutations in DR genes (HR = 3.0126, 95% CI 1.0707 to 8.4764, p = 0.0367) and the MLR (HR = 1.0018, 95%CI 1.0005 to 1.0032, p = 0.009) were significantly related to worse survival.

CONCLUSIONS

The combination of mutated repair genes and MLR-H, which is associated with a worse survival in our series of PDAC patients treated with conventional chemotherapy protocols, might become a predictive biomarker of response to immunotherapy in addition to its prognostic role in predicting survival.

Isolated pulmonary metastases in pancreatic ductal adenocarcinoma: a review of current evidence

Despite recent advances in cancer therapeutics, pancreatic ductal adenocarcinoma (PDAC) remains a lethal disease with a 5-year overall survival of only 10%. Since either at or within a few months of diagnosis, most patients with PDAC will present with metastatic disease, a more individualized approach to select patients who may benefit from more aggressive therapy has been suggested. Although studies have reported improved survival in PDAC and isolated pulmonary metastasis (ISP) compared to extrapulmonary metastases, such findings remain controversial. Furthermore, the added benefit of pulmonary metastasectomy and other lung-directed therapies remains unclear. In this review, we discuss the metastatic pattern of PDAC, evaluate the available evidence in the literature for improved survival in PDAC and ISP, evaluate the evidence for the added benefit of pulmonary metastasectomy and other lung-directed therapies, identify prognostic factors for survival, discuss the biological basis for the reported improved survival and identify areas for further research.

TP53 missense mutation reveals gain-of-function properties in small-sized KRAS transformed pancreatic ductal adenocarcinoma

BACKGROUND

Although the molecular features of pancreatic ductal adenocarcinoma (PDAC) have been well described, the impact of detailed gene mutation subtypes on disease progression remained unclear. This study aimed to evaluate the impact of different TP53 mutation subtypes on clinical characteristics and outcomes of patients with PDAC.

METHODS

We included 639 patients treated with PDAC in Ruijin Hospital affiliated to Shanghai Jiaotong University School of Medicine between Jan 2019 and Jun 2021. The genomic alterations of PDAC were analyzed, and the association of TP53 mutation subtypes and other core gene pathway alterations with patients' clinical characteristics were evaluated by Chi-squared test, Kaplan-Meier method and Cox regression model.

RESULTS

TP53 missense mutation was significantly associated with poor differentiation in KRASmut PDAC (50.7% vs. 36.1%, P = 0.001). In small-sized (≤ 2 cm) KRASmut tumors, significantly higher LNs involvement (54.8% vs. 23.5%, P = 0.010) and distal metastic rate (20.5% vs. 2.9%, P = 0.030) were observed in those with TP53 missense mutation instead of truncating mutation. Compared with TP53 truncating mutation, missense mutation was significantly associated with reduced DFS (6.6 [5.6-7.6] vs. 9.2 [5.2-13.3] months, HR 0.368 [0.200-0.677], P = 0.005) and OS (9.6 [8.0-11.1] vs. 18.3 [6.7-30.0] months, HR 0.457 [0.248-0.842], P = 0.012) in patients who failed to receive chemotherapy, while higher OS (24.2 [20.8-27.7] vs. 23.8 [19.0-28.5] months, HR 1.461 [1.005-2.124], P = 0.047) was observed in TP53missense cases after chemotherapy.

CONCLUSIONS

TP53 missense mutation was associated with poor tumor differentiation, and revealed gain-of-function properties in small-sized KRAS transformed PDAC. Nonetheless, it was not associated with insensitivity to chemotherapy, highlighting the neoadjuvant therapy before surgery as the potential optimized strategy for the treatment of a subset of patients.

The role of diagnostic, prognostic, and predictive biomarkers in the management of early pancreatic cancer

Despite modern advances in cancer medicine, pancreatic cancer survival remains unchanged at just 12%. For the small proportion of patients diagnosed with 'early' (upfront or borderline resectable) disease, recurrences are common, and many recur soon after surgery. Whilst chemotherapy has been shown to increase survival in this cohort, the morbidity of surgery renders many candidates unsuitable for adjuvant treatment. Due to this, and the success of upfront chemotherapy in the advanced setting, use of neoadjuvant chemotherapy has been introduced in patients with upfront or borderline resectable disease. Randomized controlled trials have been conducted to compare upfront surgery to neoadjuvant chemotherapy in this patient cohort, opinions on the ideal upfront treatment approach are divided. This lack of consensus has highlighted the need for biomarkers to assist in clinical decision making. This review analyses the potential diagnostic, prognostic and predictive biomarkers that may assist in the diagnosis and management of early (upfront and borderline resectable) pancreatic cancer.

Emerging Prognostic and Predictive Factors in Pancreatic Cancer

Pancreatic cancer is a lethal disease with increasing incidence and high recurrence rates and is currently resistant to conventional therapies. Moreover, it displays extensive morphologic and molecular intratumoral and intertumoral heterogeneity and a mostly low mutational burden, failing to induce significant antitumor immunity. Thus, immunotherapy has shown limited effect in pancreatic cancer, except in rare tumors with microsatellite instability, constituting <1% of the cases. Currently, new methods, including single-cell and single-nucleus RNA sequencing, have refined and expanded the 2-group molecular classification based on bulk RNA sequencing (classical and basal-like subtypes), identifying hybrid forms and providing us with a comprehensive map of the tumor cell subsets that drive gene expression during tumor evolution, simultaneously giving us insight into therapy resistance and metastasis. Additionally, deeper profiling of the tumor microenvironment of pancreatic cancer by using spatial analyses and multiplex imaging techniques has improved our understanding of the heterogeneous distribution of both adaptive and innate immune components with their protumor and antitumor properties. By integrating host immune response patterns, as defined by spatial transcriptomic and proteomic analysis and multiplex immunofluorescence, with molecular and morphologic features of the tumors, we can increasingly understand the genetic, immunologic, and morphologic background of pancreatic cancer and recognize the potential predictors for different treatment modalities.

Exploiting the molecular subtypes and genetic landscape in pancreatic cancer: the quest to find effective drugs

Pancreatic Ductal Adenocarcinoma (PDAC) is a very lethal disease that typically presents at an advanced stage and is non-compliant with most treatments. Recent technologies have helped delineate associated molecular subtypes and genetic variations yielding important insights into the pathophysiology of this disease and having implications for the identification of new therapeutic targets. Drug repurposing has been evaluated as a new paradigm in oncology to accelerate the application of approved or failed target-specific molecules for the treatment of cancer patients. This review focuses on the impact of molecular subtypes on key genomic alterations in PDAC, and the progress made thus far. Importantly, these alterations are discussed in light of the potential role of drug repurposing in PDAC.

A Novel HOXA10-Associated 5-Gene-Based Prognostic Signature for Stratification of Short-term Survivors of Pancreatic Ductal Adenocarcinoma

PURPOSE

Despite the significant association of molecular subtypes with poor prognosis in patients with pancreatic ductal adenocarcinoma (PDAC), few efforts have been made to identify the underlying pathway(s) responsible for this prognosis. Identifying a clinically relevant prognosis-based gene signature may be the key to improving patient outcomes.

EXPERIMENTAL DESIGN

We analyzed the transcriptomic profiles of treatment-naïve surgically resected short-term survivor (STS) and long-term survivor (LTS) tumors (GSE62452) for expression and survival, followed by validation in several datasets. These results were corroborated by IHC analysis of PDAC-resected STS and LTS tumors. The mechanism of this differential survival was investigated using CIBERSORT and pathway analyses.

RESULTS

We identified a short-surviving prognostic subtype of PDAC with a high degree of significance (P = 0.018). One hundred thirty genes in this novel subtype were found to be regulated by a master regulator, homeobox gene HOXA10, and a 5-gene signature derived from these genes, including BANF1, EIF4G1, MRPS10, PDIA4, and TYMS, exhibited differential expression in STSs and a strong association with poor survival. This signature was further associated with the proportion of T cells and macrophages found in STSs and LTSs, demonstrating a potential role in PDAC immunosuppression. Pathway analyses corroborated these findings, revealing that this HOXA10-driven prognostic signature is associated with immune suppression and enhanced tumorigenesis.

CONCLUSIONS

Overall, these findings reveal the presence of a HOXA10-associated prognostic subtype that can be used to differentiate between STS and LTS patients of PDAC and inform on the molecular interactions that play a role in this poor prognosis.

The Mutation Portraits of Oncogenes and Tumor Supressor Genes in Predicting the Overall Survival in Pancreatic Cancer: A Bayesian Network Meta-Analysis

INTRODUCTION

In pancreatic cancer, the carcinogenesis can not be separated from genetics mutations. The portraits of genes alterations majorily including oncogenes (KRAS, HER2, PD-L1) and tumor supressor genes (P53, CDKN2A, SMAD4). Besides being notorious a screening marker, the genetic mutations were related to the prognosis of pancreatic cancer. The aim of this study is to determine the genetic mutations portrait in predicting the overall survival in pancreatic cancer.

METHODS

The network meta analysis (NMA) was registered in PROSPERO (CRD42023397976) and conducted in accordance with the PRISMA-P (Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols) in addition of NMA extension guidance. Comprehensive searches were done including all studies which reported the overall survival of pancreatic cancer subjects with KRAS, HER2, PD-L1, P53, CDKN2A, SMAD4. Data were collected and analysis will be done based on Bayesian method, Markov Chain Monte Carlo algorithm, using BUGSnet package in R studio. Transivity was controlled by methods and consistency of the NMA will be fitted by deviance information criterion. Data analysis in NMA were presented in Sucra plot, league table, and forest plot.

RESULTS

Twenty-four studies were included in this NMA with 4613 total subjects. The NMA was conducted in random-effects, consistent, and convergence model. Relative to control, the genetic mutation of SMAD4 (HR 1.84; 95%CI 1.39-2.46), HER2 (HR 1.76; 95%CI 1.14-2.71), and KRAS (HR 1.7; 95%CI 1.19-2.48) were significant to have worse survival. The mutations of PD-L1, P53, and CDKN2A also showed poor survival, but not statistically significant compared to control.

CONCLUSION

In pancreatic cancer, the mutation of SMAD4 predicted the worst overall survival, compared to control, also mutation of HER2, KRAS, PD-L1, P53, and CDKN2A.

A multiplexed time-resolved fluorescence resonance energy transfer ultrahigh-throughput screening assay for targeting SMAD4-SMAD3-DNA complex

The signaling pathway of transforming growth factor-beta (TGFβ) plays crucial roles in the establishment of an immunosuppressive tumor microenvironment, making anti-TGFβ agents a significant area of interest in cancer immunotherapy. However, the clinical translation of current anti-TGFβ agents that target upstream cytokines and receptors remains challenging. Therefore, the development of small molecule inhibitors specifically targeting SMAD4, the downstream master regulator of TGFβ pathway, would offer an alternative approach with significant therapeutic potential for anti-TGF-β signaling. In this study, we present the development of a cell lysate-based multiplexed time-resolved fluorescence resonance energy transfer (TR-FRET) assay in an ultrahigh-throughput screening (uHTS) 1536-well plate format. This assay enables simultaneous monitoring of the protein-protein interaction (PPI) between SMAD4 and SMAD3, as well as the protein-DNA interaction (PDI) between SMADs and their consensus DNA binding motif. The multiplexed TR-FRET assay exhibits high sensitivity, allowing the dynamic analysis of the SMAD4-SMAD3-DNA complex at single amino acid resolution. Moreover, the multiplexed uHTS assay demonstrates robustness for screening small molecule inhibitors. Through a pilot screening of an FDA-approved and bioactive compound library, we identified gambogic acid and gambogenic acid as potential hit compounds. These proof-of-concept findings underscore the utility of our optimized multiplexed TR-FRET platform for large-scale screening to discover small molecule inhibitors that target the SMAD4-SMAD3-DNA complex as novel anti-TGFβ signaling agents.

Pancreatic cancer in young adults - an evolving entity?

The incidence of early-onset pancreatic cancer (EOPC) among young population (<50 years) is rising in the last decade, with gender, medical overtreatment, and genetic factors as the risk factors in EOPC. Nevertheless, the role of genetic factors in the development of EOPC needs further exploration since the studies were carried out with small sample size and ambiguous evidence. Notable, the high incidence of pathogenic germline variant (PGV) appears to be involved in EOPC. Compared with average-age-onset pancreatic cancer (AOPC), EOPC patients display a distinctive genomic feature on several well-known tumor suppressor and oncogenic genes including, including SMAD4, RAS wild wild-type, CDKN2A BRCA1, BRCA2 and FOXC2, which is different from the findings of studies with AOPC and LOPC, suggesting the dynamic evolving entity of EOPC. In addition, the potential gender-related incidence found in several countries also suggests the involvement of genetic or socioenvironmental factors in the development of AOPC. Therefore, further prospective epidemiological and molecular studies are warranted to elucidate the shifting epidemiology of this disease and, most importantly, to better exploit the opportunities for the early diagnosis of the disease.

TP53 Gain-of-Function and Non-Gain-of-Function Mutations Are Associated With Differential Prognosis in Advanced Pancreatic Ductal Adenocarcinoma

PURPOSE

To examine the impact of TP53 gain-of-function (GOF) and non-GOF mutations on prognosis of advanced pancreatic ductal adenocarcinoma (PDAC) among patients with KRAS, CDKN2A, and SMAD4 comutations.

METHODS

This cohort included patients with locally advanced, recurrent, and de novo metastatic PDAC with next-generation sequencing performed from November 2017 to May 2022. We defined R175H, R248W, R248Q, R249S, R273H, R273L, and R282W as GOF and all other p53 mutations (mutp53) as non-GOF. We used Cox regression modeling to examine the association between GOF and non-GOF mutp53 and overall survival (OS), adjusting for demographics, performance status, Charlson comorbidity index, receipt of chemotherapy, and KRAS, CDKN2A, and SMAD4 comutations.

RESULTS

Of 893 total eligible patients, 68.5% had tumors with mutp53, 90.1% had KRAS mutations (mutKRAS), 44.7% had CDKN2A mutations (mutCDKN2A), and 17.0% had SMAD4 mutations. Among patients with mutp53, 121 had GOF and 491 had non-GOF. GOF mutp53 was associated with worse OS than non-GOF mutp53 (hazard ratio [HR], 1.27; 95% CI, 1.02 to 1.59) and wild-type p53 (wtp53; HR, 1.24; 95% CI, 0.98 to 1.57), whereas non-GOF was not associated with worse OS than wtp53 (HR, 0.95; 95% CI, 0.80 to 1.13). In addition, mutKRAS was associated with worse OS than wild-type KRAS in patients with mutCDKN2A (HR, 1.57; 95% CI, 0.88 to 2.80) but not in patients with wild-type CDKN2A (HR, 1.03; 95% CI, 0.76 to 1.39).

CONCLUSION

GOF and non-GOF mutp53 were associated with differential prognosis in advanced PDAC. The adverse effect of mutKRAS on OS appeared to be primarily driven by patients with mutCDKN2A. Our results provide new insight that could be helpful for prognostic stratification in clinical practice and for aiding future clinical trial designs.

Pancreatic cancer: Advances and challenges

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest cancers. Significant efforts have largely defined major genetic factors driving PDAC pathogenesis and progression. Pancreatic tumors are characterized by a complex microenvironment that orchestrates metabolic alterations and supports a milieu of interactions among various cell types within this niche. In this review, we highlight the foundational studies that have driven our understanding of these processes. We further discuss the recent technological advances that continue to expand our understanding of PDAC complexity. We posit that the clinical translation of these research endeavors will enhance the currently dismal survival rate of this recalcitrant disease.

Mitoxantrone and Mitoxantrone-Loaded Iron Oxide Nanoparticles Induce Cell Death in Human Pancreatic Ductal Adenocarcinoma Cell Spheroids

Pancreatic ductal adenocarcinoma is a hard-to-treat, deadly malignancy. Traditional treatments, such as surgery, radiation and chemotherapy, unfortunately are still not able to significantly improve long-term survival. Three-dimensional (3D) cell cultures might be a platform to study new drug types in a highly reproducible, resource-saving model within a relevant pathophysiological cellular microenvironment. We used a 3D culture of human pancreatic ductal adenocarcinoma cell lines to investigate a potential new treatment approach using superparamagnetic iron oxide nanoparticles (SPIONs) as a drug delivery system for mitoxantrone (MTO), a chemotherapeutic agent. We established a PaCa DD183 cell line and generated PANC-1^{SMAD4 (-/-)} cells by using the CRISPR-Cas9 system, differing in a prognostically relevant mutation in the TGF-β pathway. Afterwards, we formed spheroids using PaCa DD183, PANC-1 and PANC-1^{SMAD4 (-/-)} cells, and analyzed the uptake and cytotoxic effect of free MTO and MTO-loaded SPIONs by microscopy and flow cytometry. MTO and SPION-MTO-induced cell death in all tumor spheroids in a dose-dependent manner. Interestingly, spheroids with a SMAD4 mutation showed an increased uptake of MTO and SPION-MTO, while at the same time being more resistant to the cytotoxic effects of the chemotherapeutic agents. MTO-loaded SPIONs, with their ability for magnetic drug targeting, could be a future approach for treating pancreatic ductal adenocarcinomas.

Systemic Therapy for Patients With Pancreatic Cancer: Current Approaches and Opportunities for Novel Avenues Toward Precision Medicine

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis with a 5-year overall survival of 11%. The disease is usually diagnosed at advanced stages, and systemic chemotherapy is the standard-of-care treatment for the majority of patients with PDAC. Although novel treatment options, such as targeted therapy and immunotherapy, have achieved substantial progress leading to practice-changing results, with FDA approvals for several solid tumors so far, the progress achieved for PDAC is relatively limited. Recent studies uncovered potential therapeutic targets for patients with PDAC, and potential therapeutic opportunities are currently being further examined. Herein, we review recent advances in systemic therapy regimens, including cytotoxic agents, targeted therapies, immunotherapy, and novel therapeutic options for managing patients with PDAC. We also elaborate on molecular profiling to guide treatment and existing therapeutic opportunities that may further advance the clinical care of patients with this devastating disease.

Case report: A unique presentation of a high-grade neuroepithelial tumor with EWSR1::PATZ1 fusion with diagnostic, molecular, and therapeutic insights

Background

EWSR1::PATZ1 fusion tumors are exceedingly rare in the central nervous system with only 14 prior cases documented. PATZ1 fusion neuroepithelial tumors are beginning to be recognized as a distinct molecular class of neoplasms that most often occur in children and young adults. These tumors are polyphenotypic, show diverse morphologic features, may be low- or high-grade, and tend to have an intermediate prognosis.

Case presentation

Herein, we present an unusual case of a high-grade neuroepithelial tumor in a young man with an EWSR1::PATZ1 fusion. This case is unique because the tumor appears to have undergone high-grade transformation from a persistent low-grade glioma, which has yet to be reported. Furthermore, this case is the first to document concurrent RB1 loss, SMAD4 loss, and TP53 inactivation in this tumor type, which correlates with high-grade transformation. Fortunately, this patient is alive 2.5 years after treatment and 18.5 years after initial presentation, which provides a unique window into how these tumors clinically behave over a long follow-up period. Finally, we discuss the altered molecular pathways that are a result of the EWSR1::PATZ1 fusion and discuss potential therapeutic targets.

Conclusion

Awareness of the emerging entity of PATZ1 fusion neuroepithelial tumors is important not only for accurate diagnostic and prognostic purposes but also for predicting response to therapy.

The effect of SMAD4 on the prognosis and immune response in hypopharyngeal carcinoma

Objectives

In malignant tumors, elevated infiltration of intratumoral CD8+ cytotoxic T cells predicts a beneficial prognosis, whereas high levels of CD15+ neutrophils in peritumor tissues indicate poor prognosis. It is unclear how SMAD4, which promotes favorable clinical outcomes and antitumor immunoregulation, along with CD8+ cytotoxic T cells and CD15+ neutrophils exert an influence on hypopharyngeal carcinoma (HPC).

Materials and methods

Specimens were collected from 97 patients with HPC. Immunohistological analyses of SMAD4, CD8+ cytotoxic T cell and CD15+ neutrophil expression were performed. SMAD4 nuclear intensity was measured, meanwhile, CD8+ cytotoxic T cells and CD15+ neutrophils were counted under a microscope. The prognostic role of SMAD4 was determined using the log-rank test and univariate and multivariate analyses. The relationship among SMAD4, CD8+ cytotoxic T cells, and CD15+ neutrophils was estimated by Mann-Whitney U test.

Results

High levels of SMAD4 were associated with favorable overall survival (OS) and disease-free survival (DFS) in HPC. Multivariate analysis suggested that SMAD4 is an independent predictor of OS and DFS. A high density of intratumoral CD8+ cytotoxic T cells and low accumulation of CD15+ neutrophils in the peritumor area were associated with longer OS and DFS. Furthermore, SMAD4 was linked to the levels of intratumoral CD8+ cytotoxic T cells and peritumoral CD15+ neutrophils. Patients with high SMAD4/high intratumoral CD8+ cytotoxic T cells or high SMAD4/low peritumoral CD15+ neutrophils showed the best prognosis.

Conclusion

SMAD4, CD8+ cytotoxic T cell level, and CD15+ neutrophil level have prognostic value in HPC. SMAD4 is a promising prognostic marker reflecting immune response in HPC.

Multiagent Chemotherapy and Stereotactic Body Radiation Therapy in Patients with Unresectable Pancreatic Adenocarcinoma: A Prospective Nonrandomized Controlled Trial

PURPOSE

In a prospective multicenter study, gemcitabine monotherapy followed by stereotactic body radiation therapy (SBRT) was well tolerated with outcomes comparable to chemoradiation for locally advanced pancreatic cancer (LAPC). Recent trials have reported improved survival with multiagent chemotherapy (MA-CTX) alone. This prospective trial explored whether SBRT could be safely delivered after MA-CTX. Herein, we report the long-term outcomes of adding SBRT after MA-CTX in LAPC patients and evaluate whether genetic profiles of specimens obtained before SBRT influence outcomes.

METHODS AND MATERIALS

This prospective nonrandomized controlled phase 2 trial enrolled 44 LAPC and 4 locally recurrent patients after multidisciplinary evaluation between 2012 and 2015 at a high-volume pancreatic cancer center. For induction CTX, most received modified FOLFIRINOX (mFFX), or gemcitabine and nab-paclitaxel (GnP) followed by 5-fraction SBRT for all. During fiducial placement, biopsies were obtained with DNA extracted for targeted sequencing using the Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets platform.

RESULTS

Median induction CTX duration was ≥4 months, and 31 patients received mFFX (65%). Among 44 LAPC patients, 17 (39%) were surgically explored, and 12 of 16 (75%) achieved a R0 resection. Median overall survival (mOS) was 20.2 and 14.6 months from diagnosis and SBRT, respectively. One- and 2-year OS from SBRT was 58% and 28%. The mOS after resection was 28.6 and 22.4 months from diagnosis and SBRT, respectively. Median local progression-free survival was 23.9 and 15.8 months from diagnosis and SBRT, respectively. The mOS for pre-SBRT CA 19-9 ≤180 U/mL versus >180 was 23.1 and 11.3 months, respectively (hazard ratio, 0.53; P = .04). Only 1 patient (2.1%) had late grade ≥2 gastrointestinal toxic effects attributable to SBRT. Despite significant pretreatment with chemotherapy, 88% of tumor specimens were effectively sequenced; survival outcomes were not significantly associated with specific mutational patterns. Quality of life was prospectively collected pre- and post-SBRT with the EORTC QLQ-C30 and PAN26 questionnaires showing no significant change.

CONCLUSIONS

SBRT was safely administered with MA-CTX with minimal toxicity. A high proportion of LAPC patients underwent R0 resection with favorable survival outcomes.

An EGFR/HER2-targeted conjugate sensitizes gemcitabine-sensitive and resistant pancreatic cancer through different SMAD4-mediated mechanisms

Chemoresistance limits its clinical implementation for pancreatic ductal adenocarcinoma (PDAC). We previously generated an EGFR/HER2 targeted conjugate, dual-targeting ligand-based lidamycin (DTLL), which shows a highly potent antitumor effect. To overcome chemoresistance in PDAC, we aim to study DTLL efficacy when combined with gemcitabine and explore its mechanisms of action. DTLL in combination with gemcitabine show a superior inhibitory effect on the growth of gemcitabine-resistant/sensitive tumors. DTLL sensitizes gemcitabine efficacy via distinct action mechanisms mediated by mothers against decapentaplegic homolog 4 (SMAD4). It not only prevents neoplastic proliferation via ATK/mTOR blockade and NF-κB impaired function in SMAD4-sufficient PDACs, but also restores SMAD4 bioactivity to trigger downstream NF-κB-regulated signaling in SMAD4-deficient tumors and to overcome chemoresistance. DTLL seems to act as a SMAD4 module that normalizes its function in PDAC, having a synergistic effect in combination with gemcitabine. Our findings provide insight into a rational SMAD4-directed precision therapy in PDAC.

Chemoresistance is a main limitation for the treatment of pancreatic ductal adenocarcinoma (PDAC). Here, the authors show that an antibody drug conjugate-like compound targeting both EGFR and HER2 overcomes gemcitabine resistance in PDAC preclinical models by mechanisms involving the tumour suppressor SMAD4.

Selective targeting BMP2 and 4 in SMAD4 negative esophageal adenocarcinoma inhibits tumor growth and aggressiveness in preclinical models

Purpose

Abnormalities within the Sonic Hedgehog (SHH), Bone Morphogenetic Protein (BMP) and SMAD4 signalling pathways have been associated with the malignant behavior of esophageal adenocarcinoma (EAC). We recently developed two specific llama-derived antibodies (VHHs), C4C4 and C8C8, which target BMP4 and BMP2/4, respectively. Here we aimed to demonstrate the feasibility of the VHHs for the treatment of EAC and to elucidate its underlying mechanism.

Methods

Gene Set Enrichment Analysis (GSEA) was performed on a TCGA dataset, while expression of SHH, BMP2/4 and SMAD4 was validated in a cohort of EAC patients. The effects of the VHHs were tested on the recently established SMAD4(-) ISO76A primary EAC cell line and its counterpart SMAD4(+) ISO76A. In a patient-derived xenograft (PDX) model, the VHHs were evaluated for their ability to selectively target tumor cells and for their effects on tumor growth and survival.

Results

High expression of BMP2/4 was detected in all SMAD4 negative EACs. SHH upregulated BMP2/4 expression and induced p38 MAPK signaling in the SMAD4(-) ISO76A cells. Inhibition of BMP2/4 by VHHs decreased the aggressive and chemo-resistant phenotype of the SMAD4(-) ISO76A but not of the SMAD4(+) ISO76A cells. In the PDX model, in vivo imaging indicated that VHHs effectively targeted tumor cells. Both VHHs significantly inhibited tumor growth and acted synergistically with cisplatin. Furthermore, we found that C8C8 significantly improved survival of the mice.

Conclusions

Our data indicate that increased BMP2/4 expression triggers aggressive non-canonical BMP signaling in SMAD4 negative EAC. Inhibiting BMP2/4 decreases malignant behavior and improves survival. Therefore, VHHs directed against BMP2/4 hold promise for the treatment of SMAD4 negative EAC.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13402-022-00689-2.

Autophagy: A Key Player in Pancreatic Cancer Progression and a Potential Drug Target

Simple Summary

With the mortality rate of pancreatic cancer predicted to rise over the coming years, it is essential that effective treatment strategies are developed as soon as possible. Pancreatic cancer has always proven very difficult to treat due to its fast growing and aggressive nature. Chemotherapeutic treatment has struggled to increase the survival rate of pancreatic cancer patients due to effective chemo-resistant properties that derive from the supporting tumor microenvironment and autophagy, a vital survival pathway. This review will explore how the autophagy pathway and tumor microenvironment help to sustain tumor survival under stress and expand into a metastatic state. Due to the comprehensive understanding of the autophagy pathway, we will highlight the potential chinks in the pancreatic tumor’s armor and identify potential targets to overcome chemo-resistance in pancreatic cancer. We will also present novel autophagy inhibitors that could reduce tumor survival and how they could be most effectively conceived.

Abstract

Pancreatic cancer is known to have the lowest survival outcomes among all major cancers, and unfortunately, this has only been marginally improved over last four decades. The innate characteristics of pancreatic cancer include an aggressive and fast-growing nature from powerful driver mutations, a highly defensive tumor microenvironment and the upregulation of advantageous survival pathways such as autophagy. Autophagy involves targeted degradation of proteins and organelles to provide a secondary source of cellular supplies to maintain cell growth. Elevated autophagic activity in pancreatic cancer is recognized as a major survival pathway as it provides a plethora of support for tumors by supplying vital resources, maintaining tumour survival under the stressful microenvironment and promoting other pathways involved in tumour progression and metastasis. The combination of these features is unique to pancreatic cancer and present significant resistance to chemotherapeutic strategies, thus, indicating a need for further investigation into therapies targeting this crucial pathway. This review will outline the autophagy pathway and its regulation, in addition to the genetic landscape and tumor microenvironment that contribute to pancreatic cancer severity. Moreover, this review will also discuss the mechanisms of novel therapeutic strategies that inhibit autophagy and how they could be used to suppress tumor progression.

Genomic characterization of undifferentiated sarcomatoid carcinoma of the pancreas

Undifferentiated sarcomatoid carcinoma (USC) of the pancreas is a rare but especially aggressive variant of pancreatic ductal adenocarcinoma (PDAC), composed of at least 80% of sarcomatoid cells. This study aimed to elucidate its clinicopathological and molecular features. The study cohort included 10 patients with pancreatic USC. Clinicopathological parameters were determined for each patient. The molecular profile was investigated using next-generation sequencing (NGS). Histologically, all tumors were hypercellular neoplasms with spindle-shaped or sarcomatoid cells. All patients showed vascular and perineural invasion. Most patients had a poor prognosis. NGS showed important similarities with conventional PDAC, including frequent alterations in the classic PDAC drivers, KRAS (100% of cases), TP53 (90%), and CDKN2A (60%). There were also some important distinctions from conventional PDAC: 1) SMAD4, a typical PDAC driver gene, was mutated in only one case (10%); 2) Another distinctive molecular feature was the recurrent KRAS amplification (30% of cases), which is very rare in conventional PDAC. It has been previously reported in another subtype of pancreatic undifferentiated carcinoma, the rhabdoid variant, and may be a key event leading to the acquisition of an undifferentiated phenotype in a subgroup of cases; 3) Lastly, in two different cases, we detected two potentially actionable targets, not belonging to the typical PDAC molecular landscape, such as MCL1 amplification and POLQ mutation. Our study sheds light on this rare tumor type, which shows aggressive biological behavior and few druggable alterations. The most distinctive molecular features of pancreatic USC are the paucity of SMAD4 alterations and recurrent KRAS amplification.

SMAD4 Controls Cancer Cell Metabolism by Regulating Methylmalonic Aciduria Cobalamin Deficiency (cbl) B Type

Suppressor of mothers against decapentaplegic homolog (SMAD) 4 is a pluripotent signaling mediator that regulates myriad cellular functions, including cell growth, cell division, angiogenesis, apoptosis, cell invasion, and metastasis, through transforming growth factor β (TGF-β)-dependent and -independent pathways. SMAD4 is a critical modulator in signal transduction and functions primarily as a transcription factor or cofactor. Apart from being a DNA-binding factor, the additional SMAD4 mechanisms in tumor suppression remain elusive. We previously identified methyl malonyl aciduria cobalamin deficiency B type (MMAB) as a critical SMAD4 binding protein using a proto array analysis. This study confirmed the interaction between SMAD4 and MMAB using bimolecular fluorescence complementation (BiFC) assay, proximity ligation assay (PLA), and conventional immunoprecipitation. We found that transient SMAD4 overexpression down-regulates MMAB expression via a proteasome-dependent pathway. SMAD4-MMAB interaction was independent of TGF-β signaling. Finally, we determined the effect of MMAB downregulation on cancer cells. siRNA-mediated knockdown of MMAB affected cancer cell metabolism in HeLa cells by decreasing ATP production and glucose consumption as well as inducing apoptosis. These findings suggest that SMAD4 controls cancer cell metabolism by regulating MMAB.

Early-onset pancreatic cancer: a review of molecular mechanisms, management, and survival

OBJECTIVES

Early-onset pancreatic cancer (EOPC) - defined as pancreatic cancer diagnosed before the age of 50 years - is associated with a poor prognosis as compared to later-onset pancreatic cancer (LOPC). Emerging evidence suggests that EOPC may exhibit a genetic signature and tumor biology that is distinct from that of LOPC. We review genetic mutations that are more prevalent in EOPC relative to LOPC and discuss the potential impact of these mutations on treatment and survival.

MATERIALS AND METHODS

Using PubMed and Medline, the following terms were searched and relevant citations assessed: "early onset pancreatic cancer," "late onset pancreatic cancer," "pancreatic cancer," "pancreatic cancer genes," and "pancreatic cancer targeted therapy."

RESULTS

Mutations in CDKN2, FOXC2, and SMAD4 are significantly more common in EOPC as compared to LOPC. In addition, limited data suggest that PI3KCA mutations are more frequently observed in EOPC as compared to LOPC. KRAS mutations are relatively rare in EOPC.

CONCLUSIONS

Genetic mutations associated with EOPC are distinct from those of LOPC. The preponderance of the evidence suggest that poor outcomes in EOPC are related both to advanced stage of presentation and unique tumor biology. The molecular and genetic features of EOPC warrant further investigation in order to optimize management.

CBX3 Regulated By YBX1 Promotes Smoking-induced Pancreatic Cancer Progression via Inhibiting SMURF2 Expression

As a key reversible and heritable mechanism of transcriptional regulation, the epigenetic modification plays a crucial role in tumorigenesis. Of note, tobacco smoking induces epigenetic modifications to promote pancreatic cancer development. Chromobox protein homolog 3 (CBX3) acts as an epigenetic regulator, modulating gene expression of downstream targets via chromatin modifications. To date, the relationship between CBX3 and smoking in pancreatic cancer remains unknown. This study aimed to uncover the specific role and underlying mechanism of CBX3 in smoking-related pancreatic cancer. The bioinformatics analyses were conducted to identify CBX3 as a key player in tobacco-induced pancreatic cancer. The abnormal upregulation of CBX3 was associated with poor prognosis in pancreatic cancer patients. Moreover, cigarette smoke extract (CSE) exposure promoted the overexpression of Y-box-binding protein 1 (YBX1), which consequently led to upregulated CBX3 in pancreatic cancer cells. We also revealed that CBX3 enhanced pancreatic cancer progression, likely by inhibiting the expression of SMAD specific E3 ubiquitin protein ligase 2 (SMURF2) and promoting the activation of TGF-β signaling. In summary, the YBX1/CBX3/SMURF2 signaling axis may be a promising therapeutic target in patients with smoking-related pancreatic cancer.

Multi-omics landscape and clinical significance of a SMAD4-driven immune signature: implications for risk stratification and frontline therapies in pancreatic cancer

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SMAD4 mutation affect the oncogenesis, progression and immunity of pancreatic cancer.

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Combined with immune subtypes, a SMAD4-driven immune signature (SDIS) was established.

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SDIS could robustly predict prognosis and efficacy in six independent cohorts.

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SDIS might serve as an attractive platform to further tailor decision-making.

SMAD4 mutation was recently implicated in promoting invasion and poor prognosis of pancreatic cancer (PACA) by regulating the tumor immune microenvironment. However, SMAD4-driven immune landscape and clinical significance remain elusive. In this study, we applied the consensus clustering and weighted correlation network analysis (WGCNA) to identify two heterogeneous immune subtypes and immune genes. Combined with SMAD4-driven genes determined by SMAD4 mutation status, a SMAD4-driven immune signature (SDIS) was developed in ICGC-AU2 (microarray data) via machine learning algorithm, and then was validated by RNA-seq data (TCGA, ICGC-AU and ICGC-CA) and microarray data (GSE62452 and GSE85916). The high-risk group displayed a worse prognosis, and multivariate Cox regression indicated that SDIS was an independent prognostic factor. In six cohorts, SDIS also displayed excellent accuracy in predicting prognosis. Moreover, the high-risk group was characterized by higher frequencies of TP53/CDKN2A mutations and SMAD4 deletion, superior immune checkpoint molecules expression and more sensitive to chemotherapy and immunotherapy. Meanwhile, the low-risk group was significantly enriched in metabolism-related pathways and suggested the potential to target tumor metabolism to develop specific drugs. Overall, SDIS could robustly predict prognosis in PACA, which might serve as an attractive platform to further tailor decision-making in chemotherapy and immunotherapy in clinical settings.

The genetic landscape of pancreatic head ductal adenocarcinoma in China and prognosis stratification

Background

Pancreatic ductal adenocarcinoma (PDAC) is the major subtype of pancreatic cancer and head PDACs show distinct characteristics from body/tail PDACs. With limited studies based on Asian population, the mutational landscape of Asian PDAC remains unclear.

Methods

One hundred fifty-one Chinese patients with head PDAC were selected and underwent targeted 425-gene sequencing. Genomic alterations, tumor mutational burden, and microsatellite instability were analyzed and compared with a TCGA cohort.

Results

The genomic landscape of Chinese and Western head PDAC had identical frequently-mutated genes including KRAS, TP53, SMAD4, and CDKN2A. KRAS hotspot in both cohorts was codon 12 but Chinese PDACs containing more G12V but fewer G12R variants. Potentially pathogenic fusions, CHD2-BRAF and KANK1-MET were identified in two KRAS wild-type patients. Serum cancer antigens CA125 and CA19-9 were positively associated with SMAD4 alterations while high CEA was enriched in wild-type CDKN2A subgroup. The probability of vascular invasion was lower in patients with RNF43 alterations. The nomogram developed including histology grade, the mutation status of SMAD4, TGFBR2, and PREX2 could calculate the risk score of prognoses validated by Chinese and TCGA cohort.

Conclusions

Chinese head PDAC contained more KRAS G12V mutation than Western population. The well-performed nomogram may improve post-operation care in real-world practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09279-9.

The Role of SMAD4 Inactivation in Epithelial-Mesenchymal Plasticity of Pancreatic Ductal Adenocarcinoma: The Missing Link?

Simple Summary

Pancreatic ductal adenocarcinoma (PDAC) is currently one of the deadliest cancers. Despite the progress that has been made in the research of patient care and the understanding of pancreatic cancer, the survival rate remains mediocre. SMAD4, a tumor-suppressor gene, is specifically inactivated in 50–55% of pancreatic cancers. The role of SMAD4 protein loss in PDAC remains controversial, but seems to be associated with worse overall survival and metastasis. Here, we review the function of SMAD4 inactivation in the context of a specific biological process called epithelial–mesenchymal transition, as it has been increasingly associated with tumor formation, metastasis and resistance to therapy. By improving our understanding of these molecular mechanisms, we hope to find new targets for therapy and improve the care of patients with PDAC.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) presents a five-year survival rate of 10% and its incidence increases over the years. It is, therefore, essential to improve our understanding of the molecular mechanisms that promote metastasis and chemoresistance in PDAC, which are the main causes of death in these patients. SMAD4 is inactivated in 50% of PDACs and its loss has been associated with worse overall survival and metastasis, although some controversy still exists. SMAD4 is the central signal transducer of the transforming growth factor-beta (TGF-beta) pathway, which is notably known to play a role in epithelial–mesenchymal transition (EMT). EMT is a biological process where epithelial cells lose their characteristics to acquire a spindle-cell phenotype and increased motility. EMT has been increasingly studied due to its potential implication in metastasis and therapy resistance. Recently, it has been suggested that cells undergo EMT transition through intermediary states, which is referred to as epithelial–mesenchymal plasticity (EMP). The intermediary states are characterized by enhanced aggressiveness and more efficient metastasis. Therefore, this review aims to summarize and analyze the current knowledge on SMAD4 loss in patients with PDAC and to investigate its potential role in EMP in order to better understand its function in PDAC carcinogenesis.

Prognostic value of SMAD4 in resectable pancreatic cancer

Introduction

The tumor gene SMAD4 was genetically inactivated in approximately half of pancreatic cancer (PC) patients. The correlation of SMAD4 gene expression in PC and its prognosis remains inconclusive. The aim of this study was to evaluate the association between loss of SMAD4 expression and the outcome of resectable PC.

Materials and Methods

A systematic review of the relevant electronic databases was conducted between SMAD4 expression and the outcome of PC patients until December 2020, including PubMed, Web of Science, and the China Journal Net. A meta-analysis was performed using STATA 12.0 and pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were used to estimate the strength of the association between SMAD4 gene expression and the prognosis of PC patients.

Results

Twelve studies were included. Our meta-analysis illustrated that there were no significant associations between the loss of SMAD4 gene expression and overall survival in resectable PC (HR=1.38, 95% CI 0.98–1.81). In addition, there was no evidence of publication bias, as showed by Begg's and Egger's test. There was no correlation between the loss of SMAD4 expression and local recurrence (OR=0.97, 95% CI 0.52–1.80, p=0.914), while the loss of SMAD4 gene expression was associated with increased risk of distant recurrence (OR=1.36, 95% CI 1.08–1.70, p=0.008).

Conclusions

After PC resection, the loss of SMAD4 gene expression was correlated with higher risk of distant recurrence, but not with local recurrence nor overall survival.

Deregulation of Transcription Factor Networks Driving Cell Plasticity and Metastasis in Pancreatic Cancer

Pancreatic cancer is a very aggressive disease with 5-year survival rates of less than 10%. The constantly increasing incidence and stagnant patient outcomes despite changes in treatment regimens emphasize the requirement of a better understanding of the disease mechanisms. Challenges in treating pancreatic cancer include diagnosis at already progressed disease states due to the lack of early detection methods, rapid acquisition of therapy resistance, and high metastatic competence. Pancreatic ductal adenocarcinoma, the most prevalent type of pancreatic cancer, frequently shows dominant-active mutations in KRAS and TP53 as well as inactivation of genes involved in differentiation and cell-cycle regulation (e.g. SMAD4 and CDKN2A). Besides somatic mutations, deregulated transcription factor activities strongly contribute to disease progression. Specifically, transcriptional regulatory networks essential for proper lineage specification and differentiation during pancreas development are reactivated or become deregulated in the context of cancer and exacerbate progression towards an aggressive phenotype. This review summarizes the recent literature on transcription factor networks and epigenetic gene regulation that play a crucial role during tumorigenesis.

Metabolic reprogramming by driver mutation-tumor microenvironment interplay in pancreatic cancer: new therapeutic targets

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers globally with a mortality rate exceeding 95% and very limited therapeutic options. A hallmark of PDAC is its acidic tumor microenvironment, further characterized by excessive fibrosis and depletion of oxygen and nutrients due to poor vascularity. The combination of PDAC driver mutations and adaptation to this hostile environment drives extensive metabolic reprogramming of the cancer cells toward non-canonical metabolic pathways and increases reliance on scavenging mechanisms such as autophagy and macropinocytosis. In addition, the cancer cells benefit from metabolic crosstalk with nonmalignant cells within the tumor microenvironment, including pancreatic stellate cells, fibroblasts, and endothelial and immune cells. Increasing evidence shows that this metabolic rewiring is closely related to chemo- and radioresistance and immunosuppression, causing extensive treatment failure. Indeed, stratification of human PDAC tumors into subtypes based on their metabolic profiles was shown to predict disease outcome. Accordingly, an increasing number of clinical trials target pro-tumorigenic metabolic pathways, either as stand-alone treatment or in conjunction with chemotherapy. In this review, we highlight key findings and potential future directions of pancreatic cancer metabolism research, specifically focusing on novel therapeutic opportunities.

Mutations in key driver genes of pancreatic cancer: molecularly targeted therapies and other clinical implications

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers, with a minimal difference between its incidence rate and mortality rate. Advances in oncology over the past several decades have dramatically improved the overall survival of patients with multiple cancers due to the implementation of new techniques in early diagnosis, therapeutic drugs, and personalized therapy. However, pancreatic cancers remain recalcitrant, with a 5-year relative survival rate of <9%. The lack of measures for early diagnosis, strong resistance to chemotherapy, ineffective adjuvant chemotherapy and the unavailability of molecularly targeted therapy are responsible for the high mortality rate of this notorious disease. Genetically, PDAC progresses as a complex result of the activation of oncogenes and inactivation of tumor suppressors. Although next-generation sequencing has identified numerous new genetic alterations, their clinical implications remain unknown. Classically, oncogenic mutations in genes such as KRAS and loss-of-function mutations in tumor suppressors, such as TP53, CDNK2A, DPC4/SMAD4, and BRCA2, are frequently observed in PDAC. Currently, research on these key driver genes is still the main focus. Therefore, studies assessing the functions of these genes and their potential clinical implications are of paramount importance. In this review, we summarize the biological function of key driver genes and pharmaceutical targets in PDAC. In addition, we conclude the results of molecularly targeted therapies in clinical trials and discuss how to utilize these genetic alterations in further clinical practice.

SMAD4 represses FOSL1 expression and pancreatic cancer metastatic colonization

Metastasis is a complex and poorly understood process. In pancreatic cancer, loss of the transforming growth factor (TGF)-β/BMP effector SMAD4 is correlated with changes in altered histopathological transitions, metastatic disease, and poor prognosis. In this study, we use isogenic cancer cell lines to identify SMAD4 regulated genes that contribute to the development of metastatic colonization. We perform an in vivo screen identifying FOSL1 as both a SMAD4 target and sufficient to drive colonization to the lung. The targeting of these genes early in treatment may provide a therapeutic benefit.

Targeting immunosuppression by TGF-β1 for cancer immunotherapy

The TGF-β1 cytokine is a key mediator of many biological processes. Complex regulatory mechanisms are in place that allow one single molecule to exert so many distinct indispensable activities. The complexity of TGF-β1 biology is further illustrated by the opposing dual roles it plays during cancer progression. Risks of toxicities combined with lack of convincing therapeutical efficacy explain at least in part why therapies targeting TGF-β1 have lagged behind in past decades. However, recent successes of immunostimulatory antibodies for the immunotherapy of cancer and findings that TGF-β1 activity associates with resistance to immunotherapeutic drugs have revived the field. In this review, we discuss the biology of TGF-β1 with a special focus on its roles in regulating immune responses in the context of cancer. We describe the various therapeutic approaches available to inhibit TGF-β signalling, and more recent findings that allow selective targeting of specific sources of TGF-β activity, which may prove relevant to increase the efficacy and reduce the toxicity of cancer immunotherapy.

Large-Section Histopathology Can Better Indicate the Immune Microenvironment and Predict the Prognosis of Pancreatic Ductal Adenocarcinoma Than Small-Section Histopathology

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant tumor and is insensitive to radiotherapy and chemotherapy, as it is highly correlated with its complex tumor microenvironment (TME). A comprehensive description of PDAC’s immune microenvironment at the pathological level has not been reported, thus limiting its treatment. Previous studies have shown that large-section histopathology (LSH) can reveal the complete structure and margin of the tumor on a single slice and effectively reflect intratumoral heterogeneity. LSH, as opposed to classic small-section histopathology (SSH), can also be used to explore the infiltration state of immune cells in different regions. In the current study, EnVision immunohistochemical staining was used to explore the panoramic distribution of CD4-, CD8-, CD15-, CD20-, and CD56 (surface markers of helper T cells, cytotoxic T cells, neutrophils, B cells, and NK cells, respectively)-positive cells in 102 pairs of paraffin wax-embedded PDAC samples (LSH vs SSH) for the first time. These indicators were then analyzed, and correlations of clinicopathological characteristics with clinical prognoses were analyzed. The findings of this study show that LSH can effectively indicate more immune cells than SSH. Upregulated CD4, CD8, CD20, and CD56 or downregulated CD15 was correlated with a good prognosis in PDAC patients. However, analysis of SSH showed that only upregulated CD4 and CD8 can be used as indicators of a good prognosis. Multivariate Cox regression analysis showed that 7 variables, namely, pTNM stage (P=0.002), PDL1 expression (P=0.001), CDX2 expression (P=0.008), DPC4 expression (P=0.004), CD4 expression in LSH (P<0.001), CD8 expression in LSH (P=0.010) and CD15 expression in LSH (P=0.031), were significantly correlated with the prognosis of PDAC patients. The findings of this study indicate that LSH is an effective tool for a panoramic assessment of the immune microenvironment in pancreatic cancer patients.

Molecular alterations in pancreatic tumors

Genetic alterations in pancreatic tumors can usually be classified in: (1) Mutational activation of oncogenes; (2) Inactivation of tumor suppressor genes; and (3) Inactivation of genome maintenance genes controlling the repair of DNA damage. Endoscopic ultrasound-guided fine-needle aspiration has improved pre-operative diagnosis, but the management of patients with a pancreatic lesion is still challenging. Molecular testing could help mainly in solving these “inconclusive” specimens. The introduction of multi-gene analysis approaches, such as next-generation sequencing, has provided a lot of useful information on the molecular characterization of pancreatic tumors. Different types of pancreatic tumors (e.g., pancreatic ductal adenocarcinomas, intraductal papillary mucinous neoplasms, solid pseudopapillary tumors) are characterized by specific molecular alterations. The aim of this review is to summarize the main molecular alterations found in pancreatic tumors.

Accurate Prognosis Prediction of Pancreatic Ductal Adenocarcinoma Using Integrated Clinico-Genomic Data of Endoscopic Ultrasound-Guided Fine Needle Biopsy

The aim of this study was to investigate the clinical utility of minimal specimens acquired from endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) and perform targeted deep sequencing as a prognosis prediction tool for pancreatic ductal adenocarcinoma (PDAC). A total of 116 specimens with pathologically confirmed PDAC via EUS-FNB were tested using CancerSCAN^® panel for a customized targeted deep sequencing. Clinical prognostic factors significantly associated with survival in PDACs were as follows: stage, tumor mass size, tumor location, metastasis, chemotherapy, and initial CA19-9 level. A total of 114 patients (98.3%) had at least a single genetic alteration, and no mutations were detected in two patients, although they were qualified for the targeted deep sequencing. The frequencies of major gene mutations responsible for PDACs were KRAS 90%, CDKN2A 31%, TP53 77%, and SMAD4 29%. A somatic point mutation of NF1, copy number alteration of SMAD4, and loss-of-function of CDKN2A were significantly associated genetic factors for overall survival. Moreover, BRCA2 point mutation was related to liver metastasis. Finally, a clinico-genomic model was developed to estimate the prognosis of patients with PDAC based on clinical parameters and genetic alterations affecting survival in patients; 20 single nucleotide variants and three copy number variations were selected. Targeted deep sequencing on minimal specimens of PDACs was performed, and it was applied to establish a clinico-genomic model for prognosis prediction.

Association of SMAD4 loss with drug resistance in clinical cancer patients: A systematic meta-analysis

Background

Drug resistance frequently led to the failure of chemotherapy for malignant cancers, hence causing cancer relapse. Thus, understanding mechanism of drug resistance in cancer is vital to improve the treatment efficacy. Here, we aim to evaluate the association between SMAD4 expression and the drug resistance in cancers by performing a meta-analysis.

Method

Relevant studies detecting SMAD4 expression in cancer patients treated with chemo-drugs up till December 2020 were systematically searched in four common scientific databases using selected keywords. The pooled hazard ratio (HR) was the ratio of hazard rate between SMAD4^neg population vs SMAD4^pos population. The HRs and risk ratios (RRs) with 95% confidence intervals (CIs) were used to explore the association between SMAD4 expression losses with drug resistance in cancers.

Result

After an initial screening according to the inclusion and exclusion criteria, eleven studies were included in the meta-analysis. There were a total of 2092 patients from all the included studies in this analysis. Results obtained indicated that loss of SMAD4 expression was significantly correlated with drug resistance with pooled HRs (95% CI) of 1.23 (1.01–1.45), metastasis with pooled RRs (95% CI) of 1.10 (0.97–1.25) and recurrence with pooled RRs (95% CI) of 1.32 (1.06–1.64). In the subgroup analysis, cancer type, drug type, sample size and antibody brand did not affect the significance of association between loss of SMAD4 expression and drug resistance. In addition, there was no evidence of publication bias as suggested by Begg’s test.

Conclusion

Findings from our meta-analysis demonstrated that loss of SMAD4 expression was correlated with drug resistance, metastasis and recurrence. Therefore, SMAD4 expression could be potentially used as a molecular marker for cancer resistance.

Hypomorph mutation-directed small-molecule protein-protein interaction inducers to restore mutant SMAD4-suppressed TGF-β signaling

Tumor suppressor genes represent a major class of oncogenic drivers. However, direct targeting of loss-of-function tumor suppressors remains challenging. To address this gap, we explored a variant-directed chemical biology approach to reverse the lost function of tumor suppressors using SMAD4 as an example. SMAD4, a central mediator of the TGF-β pathway, is recurrently mutated in many tumors. Here, we report the development of a TR-FRET technology that recapitulated the dynamic differential interaction of SMAD4 and SMAD4^R361H with SMAD3 and identified Ro-31-8220, a bisindolylmaleimide derivative, as a SMAD4^R361H/SMAD3 interaction inducer. Ro-31-8220 reactivated the dormant SMAD4^R361H-mediated transcriptional activity and restored TGF-β-induced tumor suppression activity in SMAD4 mutant cancer cells. Thus, demonstration of Ro-31-8220 as a SMAD4^R361H/SMAD3 interaction inducer illustrates a general strategy to reverse the lost function of tumor suppressors with hypomorph mutations and supports a systematic approach to develop small-molecule protein-protein interaction (PPI) molecular glues for biological insights and therapeutic discovery.

SMAD4 loss is associated with response to neoadjuvant chemotherapy plus hydroxychloroquine in patients with pancreatic adenocarcinoma

SMAD4, a tumor suppressor gene, is lost in up to 60%–90% of pancreatic adenocarcinomas (PDAs). Loss of SMAD4 allows tumor progression by upregulating autophagy, a cell survival mechanism that counteracts apoptosis and allows intracellular recycling of macromolecules. Hydroxychloroquine (HCQ) is an autophagy inhibitor. We studied whether HCQ treatment in SMAD4 deficient PDA may prevent therapeutic resistance induced by autophagy upregulation. We retrospectively analyzed the SMAD4 status of patients with PDA enrolled in two prospective clinical trials evaluating pre‐operative HCQ. The first dose escalation trial demonstrated the safety of preoperative gemcitabine with HCQ (NCT01128296). More recently, a randomized trial of gemcitabine/nab‐paclitaxel +/− HCQ evaluated Evans Grade histopathologic response (NCT01978184). The effect of SMAD4 loss on response to HCQ and chemotherapy was studied for association with clinical outcome. Fisher’s exact test and log‐rank test were used to assess response and survival. Fifty‐two patients receiving HCQ with neoadjuvant chemotherapy were studied. Twenty‐five patients had SMAD4 loss (48%). 76% of HCQ‐treated patients with SMAD4 loss obtained a histopathologic response greater than or equal to 2A, compared with only 37% with SMAD4 intact (p = 0.006). Although loss of SMAD4 has been associated with worse outcomes, in the current study, loss of SMAD4 was not associated with a detriment in median overall survival in HCQ‐treated patients (34.43 months in SMAD4 loss vs. 27.27 months in SMAD4 intact, p = 0.18). The addition of HCQ to neoadjuvant chemotherapy in patients with PDA may improve treatment response in those with SMAD4 loss. Further study of the relationship among SMAD4, autophagy, and treatment outcomes in PDA is warranted.

Consequences of Mutations and Abnormal Expression of SMAD4 in Tumors and T Cells

SMAD4 is a typical tumor suppressor in the TGF-β signaling pathway. In human cancers, SMAD4 is frequently mutated and inactivated. In recent years, the consequences of mutations and inactivation of SMAD4 are gradually becoming clearer. Most of the mutations have negative consequences and reduce the chances of survival of their carriers. Loss of SMAD4 functions due to mutations or abnormal expression can suppress the inhibition of tumor growth and support the tumor progression. Functions of SMAD4 and its variants in T cells are being studied extensively, to better understand the SMAD4 functions in T cells. In this review, we mainly discuss the recently reported consequences of mutations and abnormal expression of SMAD4 in tumors, and the effects of loss, deficiency or mutation of SMAD4 and its T cells, to show the use of SMAD4 mutations in cancer diagnosis and therapeutic strategies.

SMAD4 mutation correlates with poor prognosis in non-small cell lung cancer

SMAD4 is an intracellular signaling mediator of the TGF-β pathway. Its mutation was commonly observed in gastrointestinal cancers, such as pancreatic cancer. The loss of SMAD4 on immunohistochemical staining is often used to suggest a pancreaticobiliary differentiation in evaluating a metastatic adenocarcinoma with unknown origin. However, the function and molecular mechanism of SMAD4 in non-small cell lung cancer (NSCLC) development are largely unknown. Thus, we studied the correlation between SMAD4 mutations and clinico-molecular features in the patients with NSCLC. We reported the frequencies and prognostic values of SMAD4 mutations in a Chinese NSCLC cohort using next-generation sequencing. The NSCLC cases from several public databases, including The Cancer Genome Atlas and others, were also used in this study to elucidate SMAD4-related molecular partners and mechanisms. Integrated bioinformatics analyses were conducted, such as analysis of Gene Ontology enrichment analysis, gene set enrichment analysis (GSEA), and survival analysis. Immunohistochemistry showed that the tissues harboring SMAD4 mutations tended to show SMAD4 deficiency or loss, while SMAD4 expression was significantly reduced at all stages of NSCLC cases. We found that reduced SMAD4 expression was more frequent in the patients with poor disease-free survival and resistance to platinum-based chemotherapy. SMAD4 mutation was an independent risk factor for the survival of NSCLC patients. The expression of SMAD4 was associated with that of SMAD2. The GSEA showed that SMAD4 might promote NSCLC progression by regulating proliferation, adhesion, and immune response. In conclusion, these data suggest that SMAD4 mutation or loss as well as reduced expression can be used to identify the NSCLC patients with poor survival and resistance to platinum-based chemotherapy. SMAD4 may be a predictive marker or therapeutic target in NSCLC. The source code and user's guide are freely available at Github: https://github.com/wangyue77-ab/smad4 .

SMAD4 loss limits the vulnerability of pancreatic cancer cells to complex I inhibition via promotion of mitophagy

Pancreatic cancer is one of the deadliest forms of cancer, which is attributed to lack of effective treatment options and drug resistance. Mitochondrial inhibitors have emerged as a promising class of anticancer drugs, and several inhibitors of the electron transport chain (ETC) are being clinically evaluated. We hypothesized that resistance to ETC inhibitors from the biguanide class could be induced by inactivation of SMAD4, an important tumor suppressor involved in transforming growth factor β (TGFβ) signaling, and associated with altered mitochondrial activity. Here we show that, paradoxically, both TGFβ-treatment and the loss of SMAD4, a downstream member of TGFβ signaling cascade, induce resistance to biguanides, decrease mitochondrial respiration, and fragment the mitochondrial network. Mechanistically, the resistance of SMAD4-deficient cells is mediated by increased mitophagic flux driven by MAPK/ERK signaling, whereas TGFβ-induced resistance is autophagy-independent and linked to epithelial-to-mesenchymal transition (EMT). Interestingly, mitochondria-targeted tamoxifen, a complex I inhibitor under clinical trial, overcomes resistance mediated by SMAD4-deficiency or TGFβ signaling. Our data point to differential mechanisms underlying the resistance to treatment in PDAC arising from TGFβ signaling and SMAD4 loss, respectively. The findings will help the development of mitochondria-targeted therapy for pancreatic cancer patients with SMAD4 as a plausible predictive marker.

Longitudinal tracking of 97 esophageal adenocarcinomas using liquid biopsy sampling

BACKGROUND

The incidence of esophageal adenocarcinoma (EAC) is rapidly rising and has a 5-year survival rate of <20%. Beyond TNM (tumor-node-metastasis) staging, no reliable risk stratification tools exist and no large-scale studies have profiled circulating tumor DNA (ctDNA) at relapse in EAC. Here we analyze the prognostic potential of ctDNA dynamics in EAC, taking into account clonal hematopoiesis with indeterminate potential (CHIP).

PATIENTS AND METHODS

A total of 245 samples from 97 patients treated with neoadjuvant chemotherapy and surgery were identified from the prospective national UK Oesophageal Cancer Clinical and Molecular Stratification (OCCAMS) consortium data set. A pan-cancer ctDNA panel comprising 77 genes was used. Plasma and peripheral blood cell samples were sequenced to a mean depth of 7082× (range 2196-28 524) and ctDNA results correlated with survival.

RESULTS

Characteristics of the 97 patients identified were as follows: 83/97 (86%) male, median age 68 years (SD 9.5 years), 100% cT3/T4, 75% cN+. EAC-specific drivers had higher variant allele fractions than passenger mutations. Using stringent quality criteria 16/79 (20%) were ctDNA positive following resection; recurrence was observed in 12/16 (75%) of these. As much as 78/97 (80%) had CHIP analyses that enabled filtering for CHIP variants, which were found in 18/78 (23%) of cases. When CHIP was excluded, 10/63 (16%) patients were ctDNA positive and 9/10 of these (90%) recurred. With correction for CHIP, median cancer-specific survival for ctDNA-positive patients was 10.0 months versus 29.9 months for ctDNA-negative patients (hazard ratio 5.55, 95% confidence interval 2.42-12.71; P = 0.0003). Similar outcomes were observed for disease-free survival.

CONCLUSIONS

We demonstrate in a large, national, prospectively collected data set that ctDNA in plasma following surgery for EAC is prognostic for relapse. Inclusion of peripheral blood cell samples can reduce or eliminate false positives from CHIP. In future, post-operative ctDNA could be used to risk stratify patients into high- and low-risk groups for intensification or de-escalation of adjuvant chemotherapy.

JNK signaling as a target for anticancer therapy

The JNKs are members of mitogen-activated protein kinases (MAPK) which regulate many physiological processes including inflammatory responses, macrophages, cell proliferation, differentiation, survival, and death. It is increasingly clear that the continuous activation of JNKs has a role in cancer development and progression. Therefore, JNKs represent attractive oncogenic targets for cancer therapy using small molecule kinase inhibitors. Studies showed that the two major JNK proteins JNK1 and JNK2 have opposite functions in different types of cancers, which need more specification in the design of JNK inhibitors. Some of ATP- competitive and ATP non-competitive inhibitors have been developed and widely used in vitro, but this type of inhibitors lack selectivity and inhibits phosphorylation of all JNK substrates and may lead to cellular toxicity. In this review, we summarized and discussed the strategies of JNK binding inhibitors and the role of JNK signaling in the pathogenesis of different solid and hematological malignancies.

MicroRNA-Regulated Signaling Pathways: Potential Biomarkers for Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the most aggressive and invasive type of pancreatic cancer (PCa) and is expected to be the second most common cause of cancer-associated deaths. The high mortality rate is due to the asymptomatic progression of the clinical features until the advanced stages of the disease and the limited effectiveness of the current therapeutics. Aberrant expression of several microRNAs (miRs/miRNAs) has been related to PDAC progression and thus they could be potential early diagnostic, prognostic, and/or therapeutic predictors for PDAC. miRs are small (18 to 24 nucleotides long) non-coding RNAs, which regulate the expression of key genes by targeting their 3′-untranslated mRNA region. Increased evidence has also suggested that the chemoresistance of PDAC cells is associated with metabolic alterations. Metabolic stress and the dysfunctionality of systems to compensate for the altered metabolic status of PDAC cells is the foundation for cellular damage. Current data have implicated multiple systems as hallmarks of PDAC development, such as glutamine redox imbalance, oxidative stress, and mitochondrial dysfunction. Hence, both the aberrant expression of miRs and dysregulation in metabolism can have unfavorable effects in several biological processes, such as apoptosis, cell proliferation, growth, survival, stress response, angiogenesis, chemoresistance, invasion, and migration. Therefore, due to these dismal statistics, it is crucial to develop beneficial therapeutic strategies based on an improved understanding of the biology of both miRs and metabolic mediators. This review focuses on miR-mediated pathways and therapeutic resistance mechanisms in PDAC and evaluates the impact of metabolic alterations in the progression of PDAC.