Isolation and Characterization of Patient-derived Pancreatic Ductal Adenocarcinoma Organoid Models

Pancreatic ductal adenocarcinoma (PDAC) is amongst the most lethal malignancies. Recently, next-generation organoid culture methods enabling the ...

University of California San Diego

Abscisic acid (ABA) signal transduction has been proposed to utilize cytosolic Ca(2+) in guard cell ion channel regulation. However, genetic mutants in Ca(2+) sensors that impair guard cell or plant ion channel signaling responses have not been identified, and whether Ca(2+)-independent ABA signaling mechanisms suffice for a full response remains unclear. Calcium-dependent protein kinases (CDPKs) have been proposed to contribute to central signal transduction responses in plants. However, no Arabidopsis CDPK gene disruption mutant phenotype has been reported to date, likely due to overlapping redundancies in CDPKs. Two Arabidopsis guard cell-expressed CDPK genes, CPK3 and CPK6, showed gene disruption phenotypes. ABA and Ca(2+) activation of slow-type anion channels and, interestingly, ABA activation of plasma membrane Ca(2+)-permeable channels were impaired in independent alleles of single and double cpk3cpk6 mutant guard cells. Furthermore, ABA- and Ca(2+)-induced stomatal closing were partially impaired in these cpk3cpk6 mutant alleles. However, rapid-type anion channel current activity was not affected, consistent with the partial stomatal closing response in double mutants via a proposed branched signaling network. Imposed Ca(2+) oscillation experiments revealed that Ca(2+)-reactive stomatal closure was reduced in CDPK double mutant plants. However, long-lasting Ca(2+)-programmed stomatal closure was not impaired, providing genetic evidence for a functional separation of these two modes of Ca(2+)-induced stomatal closing. Our findings show important functions of the CPK6 and CPK3 CDPKs in guard cell ion channel regulation and provide genetic evidence for calcium sensors that transduce stomatal ABA signaling.

CDPKs CPK6 and CPK3 function in ABA regulation of guard cell S-type anion- and Ca(2+)-permeable channels and stomatal closure.

The poor clinical outcome in pancreatic ductal adenocarcinoma (PDA) is attributed to intrinsic chemoresistance and a growth-permissive tumor microenvironment. Conversion of quiescent to activated pancreatic stellate cells (PSCs) drives the severe stromal reaction that characterizes PDA. Here, we reveal that the vitamin D receptor (VDR) is expressed in stroma from human pancreatic tumors and that treatment with the VDR ligand calcipotriol markedly reduced markers of inflammation and fibrosis in pancreatitis and human tumor stroma. We show that VDR acts as a master transcriptional regulator of PSCs to reprise the quiescent state, resulting in induced stromal remodeling, increased intratumoral gemcitabine, reduced tumor volume, and a 57% increase in survival compared to chemotherapy alone. This work describes a molecular strategy through which transcriptional reprogramming of tumor stroma enables chemotherapeutic response and suggests vitamin D priming as an adjunct in PDA therapy. PAPERFLICK: 

Vitamin D receptor-mediated stromal reprogramming suppresses pancreatitis and enhances pancreatic cancer therapy.

Pancreatic cancer is the most lethal common solid malignancy. Systemic therapies are often ineffective, and predictive biomarkers to guide treatment are urgently needed. We generated a pancreatic cancer patient-derived organoid (PDO) library that recapitulates the mutational spectrum and transcriptional subtypes of primary pancreatic cancer. New driver oncogenes were nominated and transcriptomic analyses revealed unique clusters. PDOs exhibited heterogeneous responses to standard-of-care chemotherapeutics and investigational agents. In a case study manner, we found that PDO therapeutic profiles paralleled patient outcomes and that PDOs enabled longitudinal assessment of chemosensitivity and evaluation of synchronous metastases. We derived organoid-based gene expression signatures of chemosensitivity that predicted improved responses for many patients to chemotherapy in both the adjuvant and advanced disease settings. Finally, we nominated alternative treatment strategies for chemorefractory PDOs using targeted agent therapeutic profiling. We propose that combined molecular and therapeutic profiling of PDOs may predict clinical response and enable prospective therapeutic selection. New approaches to prioritize treatment strategies are urgently needed to improve survival and quality of life for patients with pancreatic cancer. Combined genomic, transcriptomic, and therapeutic profiling of PDOs can identify molecular and functional subtypes of pancreatic cancer, predict therapeutic responses, and facilitate precision medicine for patients with pancreatic cancer. .

Organoid Profiling Identifies Common Responders to Chemotherapy in Pancreatic Cancer.

Despite recent advances in the treatment of cancer, pancreatic ductal adenocarcinoma (PDAC) still retains the worst survival rate of common malignancies. Late diagnosis and lack of curative therapeutic options are the most pressing clinical problems for this disease. Therefore, there is a need for patient models and biomarkers that can be applied in the clinic to identify the most effective therapy for a patient. Pancreatic ductal organoids are ex-vivo models of PDAC that can be established from very small biopsies, enabling the study of localized, advanced, and metastatic patients. Organoids models have been applied to pancreatic cancer research and offer a promising platform for precision medicine approaches.

Organoid models for translational pancreatic cancer research.

Glycosylation alterations are indicative of tissue inflammation and neoplasia, but whether these alterations contribute to disease pathogenesis is largely unknown. To study the role of glycan changes in pancreatic disease, we inducibly expressed human fucosyltransferase 3 and β1,3-galactosyltransferase 5 in mice, reconstituting the glycan sialyl-Lewis, also known as carbohydrate antigen 19-9 (CA19-9). Notably, CA19-9 expression in mice resulted in rapid and severe pancreatitis with hyperactivation of epidermal growth factor receptor (EGFR) signaling. Mechanistically, CA19-9 modification of the matricellular protein fibulin-3 increased its interaction with EGFR, and blockade of fibulin-3, EGFR ligands, or CA19-9 prevented EGFR hyperactivation in organoids. CA19-9-mediated pancreatitis was reversible and could be suppressed with CA19-9 antibodies. CA19-9 also cooperated with the  oncogene to produce aggressive pancreatic cancer. These findings implicate CA19-9 in the etiology of pancreatitis and pancreatic cancer and nominate CA19-9 as a therapeutic target.

The glycan CA19-9 promotes pancreatitis and pancreatic cancer in mice.

While great interest in health effects of natural product (NP) including dietary supplements and foods persists, promising preclinical NP research is not consistently translating into actionable clinical trial (CT) outcomes. Generally considered the gold standard for assessing safety and efficacy, CTs, especially phase III CTs, are costly and require rigorous planning to optimize the value of the information obtained. More effective bridging from NP research to CT was the goal of a September, 2018 transdisciplinary workshop. Participants emphasized that replicability and likelihood of successful translation depend on rigor in experimental design, interpretation, and reporting across the continuum of NP research. Discussions spanned good practices for NP characterization and quality control; use and interpretation of models (computational through in vivo) with strong clinical predictive validity; controls for experimental artefacts, especially for in vitro interrogation of bioactivity and mechanisms of action; rigorous assessment and interpretation of prior research; transparency in all reporting; and prioritization of research questions. Natural product clinical trials prioritized based on rigorous, convergent supporting data and current public health needs are most likely to be informative and ultimately affect public health. Thoughtful, coordinated implementation of these practices should enhance the knowledge gained from future NP research.

Improving natural product research translation: From source to clinical trial.

Pancreatic adenocarcinoma presents as a spectrum of a highly aggressive disease in patients. The basis of this disease heterogeneity has proved difficult to resolve due to poor tumor cellularity and extensive genomic instability. To address this, a dataset of whole genomes and transcriptomes was generated from purified epithelium of primary and metastatic tumors. Transcriptome analysis demonstrated that molecular subtypes are a product of a gene expression continuum driven by a mixture of intratumoral subpopulations, which was confirmed by single-cell analysis. Integrated whole-genome analysis uncovered that molecular subtypes are linked to specific copy number aberrations in genes such as mutant KRAS and GATA6. By mapping tumor genetic histories, tetraploidization emerged as a key mutational process behind these events. Taken together, these data support the premise that the constellation of genomic aberrations in the tumor gives rise to the molecular subtype, and that disease heterogeneity is due to ongoing genomic instability during progression.

Transcription phenotypes of pancreatic cancer are driven by genomic events during tumor evolution.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Author Correction: Transcription phenotypes of pancreatic cancer are driven by genomic events during tumor evolution.

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal common malignancy, with little improvement in patient outcomes over the past decades. Recently, subtypes of pancreatic cancer with different prognoses have been elaborated; however, the inability to model these subtypes has precluded mechanistic investigation of their origins. Here, we present a xenotransplantation model of PDAC in which neoplasms originate from patient-derived organoids injected directly into murine pancreatic ducts. Our model enables distinction of the two main PDAC subtypes: intraepithelial neoplasms from this model progress in an indolent or invasive manner representing the classical or basal-like subtypes of PDAC, respectively. Parameters that influence PDAC subtype specification in this intraductal model include cell plasticity and hyperactivation of the RAS pathway. Finally, through intratumoral dissection and the direct manipulation of  gene dosage, we identify a suite of -regulated secreted and membrane-bound proteins that may represent potential candidates for therapeutic intervention in patients with PDAC. SIGNIFICANCE: Accurate modeling of the molecular subtypes of pancreatic cancer is crucial to facilitate the generation of effective therapies. We report the development of an intraductal organoid transplantation model of pancreatic cancer that models the progressive switching of subtypes, and identify stochastic and RAS-driven mechanisms that determine subtype specification...

Intraductal Transplantation Models of Human Pancreatic Ductal Adenocarcinoma Reveal Progressive Transition of Molecular Subtypes.

Pancreatic cancer is an aggressive disease associated with a poor 5-year overall survival. Most patients are ineligible for surgery due to late diagnosis and are treated primarily with chemotherapy with very limited success. Pancreatic cancer is relatively insensitive to chemotherapy due to multiple factors, including reduced bioavailability of drugs to tumor cells. One strategy to improve drug efficacy with reduced toxicity is the development of antibody-drug conjugates (ADC), which have now been used successfully to treat both solid and liquid tumors. Here, we evaluate the efficacy of TR1801-ADC, a newly developed ADC composed of a MET antibody conjugated to the highly potent pyrrolobenzodiazepine toxin-linker, tesirine.

A MET Targeting Antibody-Drug Conjugate Overcomes Gemcitabine Resistance in Pancreatic Cancer.

Organotypic tissue slices prepared from patient tumors are a semi-intact ex vivo preparation that recapitulates many aspects of the tumor microenvironment (TME). While connections to the vasculature and nervous system are severed, the integral functional elements of the tumor remain intact for many days during the slice culture. During this window of time, the slice platforms offer a suite of molecular, biomechanical and functional tools to investigate PDAC biology. In this review, we first briefly discuss the development of pancreatic tissue slices as a model system. Next, we touch upon using slices as an orthogonal approach to study the TME as compared to other established 3D models, such as organoids. Distinct from most other models, the pancreatic slices contain autologous immune and other stromal cells. Taking advantage of the existing immune cells within the slices, we will discuss the breakthrough studies which investigate the immune compartment in the pancreas slices. These studies will provide an important framework for future investigations seeking to exploit or reprogram the TME for cancer therapy.

Using Organotypic Tissue Slices to Investigate the Microenvironment of Pancreatic Cancer: Pharmacotyping and Beyond.

Synthetic scaffold for pancreatic organoids.

Patient-Derived Sarcoma Organoids Offer a Novel Platform for Personalized Precision Medicine.

Epithelial neoplasms of the appendix are difficult to study preclinically given their low incidence, frequent mucinous histology, and absence of a comparable organ in mice for disease modeling. Although surgery is an effective treatment for localized disease, metastatic disease has a poor prognosis as existing therapeutics borrowed from colorectal cancer have limited efficacy. Recent studies reveal that appendiceal cancer has a genomic landscape distinct from colorectal cancer and thus preclinical models to study this disease are a significant unmet need.

An Ex Vivo Organotypic Culture Platform for Functional Interrogation of Human Appendiceal Cancer Reveals a Prominent and Heterogenous Immunological Landscape.

Hervé Tiriac

Moores Cancer Center,
Department of Surgery,
Division of Surgical Oncology,
Department of Surgery, Division of Surgical Oncology

University of California San Diego

Isolation and Characterization of Patient-derived Pancreatic Ductal Adenocarcinoma Organoid Models

Hervé Tiriac

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Moores Cancer Center,Department of Surgery,Division of Surgical Oncology,Department of Surgery, Division of Surgical Oncology

University of California San Diego

Isolation and Characterization of Patient-derived Pancreatic Ductal Adenocarcinoma Organoid Models

Moores Cancer Center,
Department of Surgery,
Division of Surgical Oncology,
Department of Surgery, Division of Surgical Oncology