Epigenetic Therapeutic Strategies to Target Molecular and Cellular Heterogeneity in Pancreatic Cancer

Background: Pancreatic ductal adenocarcinoma (PDAC) remains a major challenge in cancer medicine and is characterized by a 5-year survival rate of <10%. Compelling evidence suggests that the devastating disease outcome of PDAC patients is linked to a high degree of intra- and interindividual tumor heterogeneity, which is predominantly installed at the level of gene transcription. The cellular and molecular complexities of the disease explain the poor efficacy of “one-size-fits-all” therapeutic approaches in PDAC treatment and strongly argue for pursuing tailored therapeutic strategies to tackle PDAC. In a highly dynamic manner, a network of transcription factors and epigenetic regulatory proteins temporally and spatially control the diverse transcriptomic states determining PDAC heterogeneity. Given the reversibility of epigenetic processes, pharmacological intervention with key epigenetic drivers of PDAC heterogeneity appeals as a promising concept to shift the transcriptomic phenotype of PDAC toward a less aggressive and more chemosensible state. Summary: In this review, we discuss the chances and pitfalls of epigenetic treatment strategies in overcoming and shifting molecular and cellular PDAC heterogeneities in order to combat PDAC. To this end, we utilized the keywords “pancreatic cancer,” “heterogeneity,” and “epigenetics” to search for relevant articles on the database PubMed and selected interventional studies enrolling PDAC patients as displayed in clinicaltrails.gov to generate a synopsis of clinical trials involving epigenetic targeting. Key Messages: Targeting epigenetic regulators in PDAC represents a promising concept to reprogram molecular and cellular tumor heterogeneities in the pancreas and hence to modulate the PDAC phenotype in favor of a less aggressive and more therapy susceptible disease course. However, we just start to understand the complex interactions of epigenetic regulators in controlling PDAC plasticity, and a clinical breakthrough utilizing epigenetic targeting in PDAC patients has not been achieved yet. Nevertheless, increasing translational efforts which consider the pleiotropic effects of targeting epigenetic regulation in different cellular compartments of the tumor and that focus on the utility and sequence of combinatory treatment approaches might pave the way toward novel epigenetic treatment strategies in PDAC therapy.

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Immune Cell Modulation of the Extracellular Matrix Contributes to the Pathogenesis of Pancreatic Cancer

Biomolecules ◽

10.3390/biom11060901 ◽

2021 ◽

Vol 11 (6) ◽

pp. 901

Author(s):

Ramiz S. Ahmad ◽

Timothy D. Eubank ◽

Slawomir Lukomski ◽

Brian A. Boone

Keyword(s):

Pancreatic Cancer ◽

Extracellular Matrix ◽

Immune Cells ◽

Immune Cell ◽

Treatment Strategies ◽

Stellate Cells ◽

Pancreatic Stellate Cells ◽

Ductal Adenocarcinoma ◽

Cellular Mechanisms ◽

Novel Treatment Strategies

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy with a five-year survival rate of only 9%. PDAC is characterized by a dense, fibrotic stroma composed of extracellular matrix (ECM) proteins. This desmoplastic stroma is a hallmark of PDAC, representing a significant physical barrier that is immunosuppressive and obstructs penetration of cytotoxic chemotherapy agents into the tumor microenvironment (TME). Additionally, dense ECM promotes hypoxia, making tumor cells refractive to radiation therapy and alters their metabolism, thereby supporting proliferation and survival. In this review, we outline the significant contribution of fibrosis to the pathogenesis of pancreatic cancer, with a focus on the cross talk between immune cells and pancreatic stellate cells that contribute to ECM deposition. We emphasize the cellular mechanisms by which neutrophils and macrophages, specifically, modulate the ECM in favor of PDAC-progression. Furthermore, we investigate how activated stellate cells and ECM influence immune cells and promote immunosuppression in PDAC. Finally, we summarize therapeutic strategies that target the stroma and hinder immune cell promotion of fibrogenesis, which have unfortunately led to mixed results. An enhanced understanding of the complex interactions between the pancreatic tumor ECM and immune cells may uncover novel treatment strategies that are desperately needed for this devastating disease.

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Adjuvant and Neoadjuvant Therapy for Pancreatic Adenocarcinoma

10.2310/7800.16076 ◽

2017 ◽

Author(s):

Gregory C Wilson ◽

Brent T Xia ◽

Syed A Ahmed

Keyword(s):

Pancreatic Cancer ◽

Adjuvant Therapy ◽

Neoadjuvant Therapy ◽

Pancreatic Adenocarcinoma ◽

Locally Advanced ◽

Neoadjuvant Treatment ◽

Advanced Pancreatic Cancer ◽

Treatment Strategies ◽

Ductal Adenocarcinoma ◽

Borderline Resectable

Despite decades of advancement and research into the multimodal care of pancreatic cancer, mortality after the diagnosis of pancreatic ductal adenocarcinoma remains grim. The role of adjuvant therapy following surgical resection has been well established in the literature. However, adjuvant therapy is imperfect, and outside of a clinical trial, there are high rates of omission or delayed initiation of therapy. Neoadjuvant treatment strategies continue to be explored in the management of resectable, borderline-resectable, and locally advanced unresectable pancreatic adenocarcinoma. With improved resection rates and the possibility for tumor downstaging, neoadjuvant therapy has become standard for patients with borderline-resectable and locally advanced unresectable tumors. Additional benefits of neoadjuvant therapy in the treatment of resectable tumors include improved completion rates of systemic therapy and R0 resection rates. Future clinical trials, including the use of novel treatment agents and combination treatment strategies in both neoadjuvant and adjuvant regimens, will add value to the treatment of pancreatic adenocarcinoma. Key words: adjuvant therapy, borderline-resectable pancreatic cancer, locally advanced pancreatic cancer, neoadjuvant therapy, pancreatic adenocarcinoma, resectable disease

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Missing links — epigenetic regulators of the pancreatic cancer–associated inflammation

Clinical Science ◽

10.1042/cs20210181 ◽

2021 ◽

Vol 135 (10) ◽

pp. 1289-1293

Author(s):

Gregor Werba ◽

Tamas A. Gonda

Keyword(s):

Pancreatic Cancer ◽

Noncoding Rna ◽

Current Knowledge ◽

Treatment Strategies ◽

Therapeutic Interventions ◽

Ductal Adenocarcinoma ◽

Gastrointestinal Cancers ◽

Novel Treatment ◽

Epigenetic Regulator ◽

Novel Treatment Strategies

Abstract Pancreatic ductal adenocarcinoma (PDAC) features a hostile tumor microenvironment (TME) that renders it remarkably resistant to most therapeutic interventions. Consequently, survival remains among the poorest compared with other gastrointestinal cancers. Concerted efforts are underway to decipher the complex PDAC TME, break down barriers to efficacious therapies and identify novel treatment strategies. In the recent Clinical Science, Li and colleagues identify the long noncoding RNA KLHDC7B-DT as a crucial epigenetic regulator of IL-6 transcription in PDAC and illustrate its potent influences on the pancreatic TME. In this commentary, we introduce epigenetics in pancreatic cancer and put the findings by Li et al. in context with current knowledge.

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Conversion Surgery for Advanced Pancreatic Cancer

Journal of Clinical Medicine ◽

10.3390/jcm8111945 ◽

2019 ◽

Vol 8 (11) ◽

pp. 1945

Author(s):

Thomas Hank ◽

Oliver Strobel

Keyword(s):

Pancreatic Cancer ◽

Locally Advanced ◽

Palliative Therapy ◽

Advanced Pancreatic Cancer ◽

Treatment Strategies ◽

Ductal Adenocarcinoma ◽

Conversion Surgery ◽

Radiological Criteria ◽

Intention To Treat ◽

Conversion Rates

While primarily unresectable locally advanced pancreatic cancer (LAPC) used to be an indication for palliative therapy, a strategy of neoadjuvant therapy (NAT) and conversion surgery is being increasingly used after more effective chemotherapy regimens have become available for pancreatic ductal adenocarcinoma. While high-level evidence from prospective studies is still sparse, several large retrospective studies have recently reported their experience with NAT and conversion surgery for LAPC. This review aims to provide a current overview about different NAT regimens, conversion rates, survival outcomes and determinants of post-resection outcomes, as well as surgical strategies in the context of conversion surgery after NAT. FOLFIRINOX is the predominant regimen used and associated with the highest reported conversion rates. Conversion rates considerably vary between less than 5% and more than half of the study population with heterogeneous long-term outcomes, owing to a lack of intention-to-treat analyses in most studies and a high heterogeneity in resectability criteria, treatment strategies, and reporting among studies. Since radiological criteria of local resectability are no longer applicable after NAT, patients without progressive disease should undergo surgical exploration. Surgery after NAT has to be aimed at local radicality around the peripancreatic vessels and should be performed in expert centers. Future studies in this rapidly evolving field need to be prospective, analyze intention-to-treat populations, report stringent and objective inclusion criteria and criteria for resection. Innovative regimens for NAT in combination with a radical surgical approach hold high promise for patients with LAPC in the future.

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Overcoming erlotinib resistance with STAT3 inhibition in pancreatic cancer.

Journal of Clinical Oncology ◽

10.1200/jco.2017.35.4_suppl.304 ◽

2017 ◽

Vol 35 (4_suppl) ◽

pp. 304-304 ◽

Cited By ~ 2

Author(s):

Matthew Philip Salzberg ◽

Nipun B. Merchant

Keyword(s):

Pancreatic Cancer ◽

Kinase Inhibitor ◽

Treatment Strategies ◽

Phase Iii ◽

Human Pancreatic Cancer ◽

Ductal Adenocarcinoma ◽

Dependent Manner ◽

Egfr Inhibition ◽

Stat3 Signaling ◽

Stat3 Inhibition

304 Background: Pancreatic ductal adenocarcinoma (PDAC) remains a major therapeutic challenge. Cytotoxic chemotherapy remains the standard approach in PDAC, but results in minimal survival benefit for patients, highlighting a desperate need for novel treatment strategies. Epidermal growth factor receptor (EGFR) is overexpressed in 25-90% of PDACs and has been shown to be an adverse prognostic marker for survival, making it a rational target. To date, the combination of the EGFR tyrosine kinase inhibitor, erlotinib, with gemcitabine remains the only approved targeted therapy based on a significant, yet modest, improved overall survival when compared to gemcitabine alone in a phase III clinical trial. We have previously shown that constitutively activated signal transducer and activator of transcription 3 (STAT3) signaling is a biomarker of resistance to both gemcitabine and erlotinib. Therefore, we hypothesized that combined STAT3 and EGFR inhibition would overcome resistance to erlotinib and gemcitabine in PDAC. Methods: Human pancreatic cancer cell lines MiaPaca2 ( KRASG12C ; TP53mut ; EGFRwt) or BxPC-3 ( KRASwt ; TP53mut ; EGFRwt) were treated in a dose dependent manner with erlotinib in the presence or absence of gemcitabine. PDAC cells were additionally treated with EC50doses of a STAT3 inhibitor (AZD1480), erlotinib, and/or gemcitabine. Lysates were then collected and western blot analysis was performed to detect total and phosphorylated extracellular signal regulated kinase (ERK) or STAT3. Results: EGFR inhibition with erlotinib, with or without gemcitabine, results in decreased ERK activation, however, causes an increased activation of STAT3 signaling in both MiaPaca2 and BxPC-3 cells. Combined STAT3 and EGFR inhibition results in sustained attenuation of both phosphorylated ERK and STAT3 levels. Conclusions: Our study demonstrates that activated STAT3 signaling appears to be a mechanism of resistance to erlotinib and gemicitabine treatment in PDAC. Combining STAT3 inhibition with EGFR inhibition overcomes this resistance.

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Targeted Therapies for Pancreatic Cancer: Overview of Current Treatments and New Opportunities for Personalized Oncology

Cancers ◽

10.3390/cancers13040799 ◽

2021 ◽

Vol 13 (4) ◽

pp. 799 ◽

Cited By ~ 1

Author(s):

Cédric Leroux ◽

Georgia Konstantinidou

Keyword(s):

Pancreatic Cancer ◽

Pancreatic Ductal Adenocarcinoma ◽

Patient Outcomes ◽

Targeted Therapies ◽

Median Overall Survival ◽

Advanced Disease ◽

Treatment Strategies ◽

Ductal Adenocarcinoma ◽

Cancer Associated Fibroblasts ◽

Personalized Oncology

Cytotoxic chemotherapy remains the only treatment option for most pancreatic ductal adenocarcinoma patients. Currently, the median overall survival of patients with advanced disease rarely exceeds 1 year. The complex network of pancreatic cancer composed of immune cells, endothelial cells, and cancer-associated fibroblasts confers intratumoral and intertumoral heterogeneity with distinct proliferative and metastatic propensity. This heterogeneity can explain why tumors do not behave uniformly and are able to escape therapy. The advance in technology of whole-genome sequencing has now provided the possibility of identifying every somatic mutation, copy-number change, and structural variant in a given cancer, giving rise to personalized targeted therapies. In this review, we provide an overview of the current and emerging treatment strategies in pancreatic cancer. By highlighting new paradigms in pancreatic ductal adenocarcinoma treatment, we hope to stimulate new thoughts for clinical trials aimed at improving patient outcomes.

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Novel 3D µtissues Mimicking the Fibrotic Stroma in Pancreatic Cancer to Study Cellular Interactions and Stroma-Modulating Therapeutics

Cancers ◽

10.3390/cancers13195006 ◽

2021 ◽

Vol 13 (19) ◽

pp. 5006

Author(s):

Kunal P. Pednekar ◽

Marcel A. Heinrich ◽

Joop van Baarlen ◽

Jai Prakash

Keyword(s):

Pancreatic Cancer ◽

Tumor Cells ◽

Treatment Options ◽

Treatment Strategies ◽

Collagen Gel ◽

Current Treatment ◽

Ductal Adenocarcinoma ◽

Tumor Type ◽

Cellular Interactions

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive tumor type with low patient survival due to the low efficacy of current treatment options. Cancer-associated fibroblasts (CAFs) in the tumor microenvironment (TME) create a dense fibrotic environment around the tumor cells, preventing therapies from reaching their target. Novel 3D in vitro models are needed that mimic this fibrotic barrier for the development of therapies in a biologically relevant environment. Here, novel PDAC microtissues (µtissues) consisting of pancreatic cancer cell core surrounded by a CAF-laden collagen gel are presented, that is based on the cells own contractility to form a hard-to-penetrate barrier. The contraction of CAFs is demonstrated facilitating the embedding of tumor cells in the center of the µtissue as observed in patients. The µtissues displayed a PDAC-relevant gene expression by comparing their gene profile with transcriptomic patient data. Furthermore, the CAF-dependent proliferation of cancer cells is presented, as well as the suitability of the µtissues to serve as a platform for the screening of CAF-modulating therapies in combination with other (nano)therapies. It is envisioned that these PDAC µtissues can serve as a high-throughput platform for studying cellular interactions in PDAC and for evaluating different treatment strategies in the future.

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Emerging Role of miR-345 and Its Effective Delivery as a Potential Therapeutic Candidate in Pancreatic Cancer and Other Cancers

Pharmaceutics ◽

10.3390/pharmaceutics13121987 ◽

2021 ◽

Vol 13 (12) ◽

pp. 1987

Author(s):

Nagabhishek Sirpu Natesh ◽

Brianna M. White ◽

Maia M. C. Bennett ◽

Metin Uz ◽

Rakhee Rathnam Kalari Kandy ◽

...

Keyword(s):

Pancreatic Cancer ◽

Critical Role ◽

Tumor Development ◽

Treatment Strategies ◽

Underlying Mechanism ◽

Therapeutic Interventions ◽

Ductal Adenocarcinoma ◽

Desmoplastic Reaction ◽

Cancer Pathogenesis ◽

Effective Delivery

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with high mortality, poor prognosis, and palliative treatments, due to the rapid upregulation of alternative compensatory pathways and desmoplastic reaction. miRNAs, small non-coding RNAs, have been recently identified as key players regulating cancer pathogenesis. Dysregulated miRNAs are associated with molecular pathways involved in tumor development, metastasis, and chemoresistance in PDAC, as well as other cancers. Targeted treatment strategies that alter miRNA levels in cancers have promising potential as therapeutic interventions. miRNA-345 (miR-345) plays a critical role in tumor suppression and is differentially expressed in various cancers, including pancreatic cancer (PC). The underlying mechanism(s) and delivery strategies of miR-345 have been investigated by us previously. Here, we summarize the potential therapeutic roles of miR-345 in different cancers, with emphasis on PDAC, for miRNA drug discovery, development, status, and implications. Further, we focus on miRNA nanodelivery system(s), based on different materials and nanoformulations, specifically for the delivery of miR-345.

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The Role of Exosomes in Pancreatic Cancer From Bench to Clinical Application: An Updated Review

Frontiers in Oncology ◽

10.3389/fonc.2021.644358 ◽

2021 ◽

Vol 11 ◽

Author(s):

Kai Chen ◽

Qi Wang ◽

Marko Kornmann ◽

Xiaodong Tian ◽

Yinmo Yang

Keyword(s):

Pancreatic Cancer ◽

Tumor Heterogeneity ◽

Cell Communication ◽

Treatment Strategies ◽

Drug Carriers ◽

Clinical Applications ◽

Ductal Adenocarcinoma ◽

Gastrointestinal Malignancies ◽

Growing Body

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most dismal gastrointestinal malignancies with an overall 5-year survival rate of 8%–9%. The intra-tumor heterogeneity and special tumor microenvironment in PDAC make it challenging to develop effective treatment strategies. Exosomes are extracellular vesicles that originate from the endosomes and have a diameter of 40–160 nm. A growing body of evidence has shown that exosomes play vital roles in tumor initiation and development. Recently, extensive application of exosomes as biomarkers and drug carriers has rendered them attractive in the field of PDAC. This review summarizes the latest progress in the methodologies for isolation, modification, and tracking of exosomes, exosome-mediated cell-to-cell communication, clinical applications of exosome as minimally invasive liquid biopsy and drugs carriers, as well as their involvement in the angiogenic regulation in PDAC. In spite of these advancements, some obstacles are still required to be overcome to use the exosome-based technologies for early diagnosis or improvement of prognosis of patients with PDAC.

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Synergistic Interactions between GW8510 and Gemcitabine in an In Vitro Model of Pancreatic Cancer

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520621999210104201553 ◽

2021 ◽

Vol 21 ◽

Author(s):

Duygu Gencalp ◽

Sevcan Atay ◽

Hikmet H. Aydin ◽

Handan Ak

Keyword(s):

Cell Cycle ◽

Pancreatic Cancer ◽

Cell Viability ◽

Control Cell ◽

Survival Rates ◽

Treatment Strategies ◽

Ductal Adenocarcinoma ◽

Viability Analysis ◽

Protein Levels

Background: One of the main reasons for the poor survival rates of pancreatic cancer patients is the development of gemcitabine resistance, indicating that novel treatment strategies that have the ability to improve gemcitabine sensitivity are in need to combat this devastating disease. Methods: TCGA PAAD data was used to determine the clinicopathological significance of high RRM2 (Ribonucleotide reductase subunit M2) expression for pancreatic ductal adenocarcinoma (PDAC). The effects of GW8510 and gemcitabine on PANC-1 cell viability were determined using WST-8 assay. The potential synergistic interaction between GW8510 and gemcitabine was evaluated by the combination index (CI) analysis. The effects of GW8510 treatment on apoptosis, cell cycle, and cell migration, either in combination with gemcitabine or alone, were investigated. The effect of GW8510 on RRM2 protein levels was evaluated using ELISA assay. Results: RRM2 is significantly over-expressed in PDAC compared to healthy pancreatic tissues (p <0.0001). RRM2 mRNA expression was found to be significantly corralated with the overall survival rate of patients (HR=2.17 [1.44-3.27], p=0.00016) and the pathological stages of the disease (p=0.0054). GW8510 significantly decreased the RRM2 protein levels compared to the control. Cell viability analysis showed that GW8510 has a similar effect to gemcitabine in inhibiting PANC-1 cell viability. GW8510 was found to synergize with gemcitabine to inhibit PANC-1 cell viability and migration. However, the effects of GW8510 on PANC-1 cells could not be explained by induction of apoptosis or cell cycle arrest. Conclusion: Targeting RRM2 using GW8510 may have the potential to increase gemcitabine sensitivity in pancreatic cancer.

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