Reliable Preclinical Models Research Articles

Personalized Treatment of Advanced Gastric Cancer Guided by the MiniPDX Model.

Background The morbidity and mortality of gastric cancer are high in China. There are challenges to develop precise and individualized drug regimens for patients with gastric cancer after a standard treatment. Choosing the most appropriate anticancer drug after a patient developing drug resistance is very important to improve the patient's prognosis. MiniPDX has been widely used as a new and reliable preclinical research model to predict the sensitivity of anticancer drugs. Methods The OncoVee® MiniPDX system developed by Shanghai LIDE Biotech Co., Ltd. was used to establish the MiniPDX models using specimens of patients with gastric cancer. The cancer tissues were biopsied under endoscopy, and then, the tumor cell suspension was prepared for a drug sensitivity test by subcutaneously implanting into Balb/c-nude mice. The selected optimal regimen obtained from the MiniPDX assay was used to treat patients with drug-resistant gastric cancer. Results We successfully established an individualized and sensitive drug screening system for four patients from January 2021 to July 2021. MiniPDX models identified potentially effective drugs for these four patients, with partial remission in two of the patients after treatment and disease progression in the remaining of two patients. Severe side effects from chemotherapy or targeted therapy were not observed in all patients. Conclusion Establishing a personalized drug screening system for patients with drug-resistant gastric cancer can guide the selection of clinical drugs, improve the clinical benefit of patients, and avoid ineffective treatments. It can be an effective supplement for treatment options.

A Novel Standardized Peripheral Nerve Transection Method and a Novel Digital Pressure Sensor Device Construction for Peripheral Nerve Crush Injury.

Peripheral nerve injury (PNI) is common in all walks of life, and the most common PNIs are nerve crush and nerve transection. While optimal functional recovery after crush injury occurs over weeks, functional recovery after nerve transection with microsurgical repair and grafting is poor, and associated with permanent disability. The gold-standard treatment for nerve transection injury is microsurgical tensionless end-to-end suture repair. Since it is unethical to do experimental PNI studies in humans, it is therefore indispensable to have a simple, reliable, and reproducible pre-clinical animal model for successful evaluation of the efficacy of a novel treatment strategy. The objective of this article is two-fold: (A) To present a novel standardized peripheral nerve transection method in mice, using fibrin glue for modeling peripheral nerve transection injury, with reproducible gap distance between the severed nerve ends, and (B) to document the step-wise description of constructing a pressure sensor device for crush injury pressure measurements. We have successfully established a novel nerve transection model in mice using fibrin glue, and demonstrated that this transection method decreases surgical difficulties and variability by avoiding microsurgical manipulations on the nerve, ensuring the reproducibility and reliability of this animal model. Although it is quite impossible to exactly mimic the pathophysiological changes seen in nerve transection with sutures, we hope that the close resemblance of our novel pre-clinical model with gold-standard suturing can be easily reproduced by any lab, and that the data generated by this method significantly contributes to better understanding of nerve pathophysiology, molecular mechanisms of nerve regeneration, and the development of novel strategies for optimal functional recovery. In case of peripheral nerve crush injury, current methods rely on inter-device and operator precision to limit the variation with applied pressure. While the inability to accurately quantify the crush pressure may result in reduced reproducibility between animals and studies, there is no documentation of a pressure monitoring device that can be readily used for real-time pressure measurements. To address this deficit, we constructed a novel portable device comprised of an Arduino UNO microcontroller board and force sensitive resistor (FSR) capable of reporting the real-time pressure applied to a nerve. This novel digital pressure sensor device is cheap, easy to construct and assemble, and we believe that this device will be useful for any lab performing nerve crush injury in rodents.

Establishment and evaluation of retroperitoneal liposarcoma patient-derived xenograft models: an ideal model for preclinical study.

Retroperitoneal liposarcoma (RLPS) is one of the most common subtypes of retroperitoneal soft tissue sarcomas. It is characterized by poor sensitivity to radiotherapy and chemotherapy and a low success rate of complete surgical resection. However, there are few reliable preclinical RLPS models for target discovery and therapy research. In this study, we aimed to establish RLPS patient-derived xenograft (PDX) models that are useful for biological research and preclinical drug trials. A total of 56 freshly resected RLPS tissues were subcutaneously transplanted into non-obese diabetic-severe combined immune deficient (NOD-SCID) mice, with subsequent xenotransplantation into second-generation mice. The tumor engraftment rate of first generation PDXs was 44.64%, and higher success rates were obtained from implantations of dedifferentiated, myxous, pleomorphic, high-grade liposarcomas and those with retroperitoneal organ infiltration. The first- and second- generation PDX models preserved the histopathological morphology, gene mutation profiles and MDM2 amplification of the primary tissues. PDX models can also provide the benefit of retaining original tumor biology and microenvironment characteristics, such as abnormal adipose differentiation, elevated Ki67 levels, high microvessel density, cancer-associated fibroblast presence, and tumor-associated macrophage infiltration. Overall survival (OS) and disease-free survival (DFS) of patients with successful first-generation PDX engraftment were significantly poorer than those with failed engraftment. Treatment with MDM2 inhibitor RG7112 significantly suppressed tumor growth of DDLPS PDX in mice. In conclusion, we successfully established RLPS PDX models that were histologically, genetically, and molecularly consistent with the original tissues. These models might provide opportunities for advancing RLPS tumor biology research, facilitating the development of novel drugs, particularly those targeting MDM2 amplification, adipose differentiation process, angiogenesis, cancer-associated fibroblasts, and so on.

Transgenic rat models for cerebral amyloid angiopathy type‐1 and ‐2 and related vascular cognitive impairment and dementia (VCID)

Cerebral amyloid angiopathy (CAA) is a cerebral small vessel disease commonly found in the elderly population and in patients with Alzheimer's disease and is significant driver of vascular cognitive impairment and dementia (VCID). CAA exists in two forms: type-1 which affects small microvessels and capillaries and type-2 which primarily affects small arteries and arterioles. Our understanding of how these different forms of CAA promote VCID is hampered by reliable preclinical models. Recently, we generated novel transgenic rat models of CAA type-1 and CAA type-2 to investigate the development and pathological consequences of each type of CAA and their impact on VCID. Cohorts of CAA type-1 and CAA type-2 transgenic rats and wild-type rats were aged from three to twenty four months of age. Magnetic resonance imaging (MRI) was performed to determine the effects of progressive CAA pathology on white matter changes and emergence of cerebral microbleeds. Quantitative histological analyses were performed to measure progressive severity of CAA, neuroinflammation and cerebral microbleeds. A battery of behavioral task assessments was performed to reveal the impact of CAA on cognitive performance. CAA type-1 rats developed microvascular CAA starting at ≈3 months of age that became severe at 12 months leading to a moribund state. CAA type-2 rats developed CAA pathology later starting ≈12 months of age and progressed to 24 months. Histological analysis showed CAA type-1 rats exhibited early-onset perivascular neuroinflammation and microvascular pathology including capillary occlusions and microbleeds. In contrast, CAA type-2 rats presented little evidence of perivascular neuroinflammation and less extensive microbleeds. MR imaging showed that CAA type-1 rats presented with white matter loss at ≈6 months of age. Behavioral analysis revealed that CAA type-1 rats displayed a distinct form sensorimotor slowing that was not observed in CAA type-2 rats. CAA type-1 rats recapitulate many of the pathological features of human microvascular CAA including perivascular neuroinflammation and white matter loss and exhibit cognitive changes. In contrast, CAA type-2 rats lack these particular pathological features and did not display cognitive changes. These findings suggest that CAA-associated neuroinflammation and white matter loss may play an important role in VCID.

Modeling pulmonary cystic fibrosis in a human lung airway-on-a-chip

BackgroundCystic fibrosis (CF) is a genetic disease caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR), which results in impaired airway mucociliary clearance, inflammation, infection, and respiratory insufficiency. The development of new therapeutics for CF are limited by the lack of reliable preclinical models that recapitulate the structural, immunological, and bioelectrical features of human CF lungs. MethodsWe leveraged organ-on-a-chip technology to develop a microfluidic device lined by primary human CF bronchial epithelial cells grown under an air-liquid interface and interfaced with pulmonary microvascular endothelial cells (CF Airway Chip) exposed to fluid flow. The responses of CF and healthy Airway Chips were analyzed in the presence or absence of polymorphonuclear leukocytes (PMNs) and the bacterial pathogen, Pseudomonas aeruginosa. ResultsThe CF Airway Chip faithfully recapitulated many features of the human CF airways, including enhanced mucus accumulation, increased cilia density, and a higher ciliary beating frequency compared to chips lined by healthy bronchial epithelial cells. The CF chips also secreted higher levels of IL-8, which was accompanied by enhanced PMN adhesion to the endothelium and transmigration into the airway compartment. In addition, CF Airway Chips provided a more favorable environment for Pseudomonas aeruginosa growth, which resulted in enhanced secretion of inflammatory cytokines and recruitment of PMNs to the airway. ConclusionsThe human CF Airway Chip may provide a valuable preclinical tool for pathophysiology studies as well as for drug testing and personalized medicine.

Syrian hamsters as a model of lung injury with SARS-CoV-2 infection: Pathologic, physiologic, and detailed molecular profiling

The acute respiratory distress syndrome (ARDS) is a common complication of severe COVID-19 (coronavirus disease 2019) caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection. Knowledge of molecular mechanisms driving host responses to SARS-CoV-2 is limited by the lack of reliable preclinical models of COVID-19 that recapitulate human illness. Further, existing COVID-19 animal models are not characterized as models of experimental acute lung injury (ALI) or ARDS. Acknowledging differences in experimental lung injury in animal models and human ARDS, here we systematically evaluate a model of experimental acute lung injury as a result of SARS-CoV-2 infection in Syrian golden hamsters. Following intranasal inoculation, hamsters demonstrate acute SARS-CoV-2 infection, viral pneumonia, and systemic illness but survive infection with clearance of virus. Hamsters exposed to SARS-CoV-2 exhibited key features of experimental ALI, including histologic evidence of lung injury, increased pulmonary permeability, acute inflammation, and hypoxemia. RNA sequencing of lungs indicated upregulation of inflammatory mediators that persisted after infection clearance. Lipidomic analysis demonstrated significant differences in hamster phospholipidome with SARS-CoV-2 infection. Lungs infected with SARS-CoV-2 showed increased apoptosis and ferroptosis. Thus, SARS-CoV-2 infected hamsters exhibit key features of experimental lung injury supporting their use as a preclinical model of COVID-19 ARDS.

Patient-Derived Xenografts Are a Reliable Preclinical Model for the Personalized Treatment of Epithelial Ovarian Cancer.

To generate robust patient-derived xenograft (PDX) models for epithelial ovarian cancer (EOC), analyze the resemblance of PDX models to the original tumors, and explore factors affecting engraftment rates, fresh cancer tissues from a consecutive cohort of 158 patients with EOC were collected to construct subcutaneous PDX models. Paired samples of original tumors and PDX tumors were compared at the genome, transcriptome, protein levels, and the platinum-based chemotherapy response was evaluated to ensure the reliability of the PDXs. Univariate and multivariate analyses were used to determine the factors affecting the engraftment rates. The engraftment success rate was 58.23% (92/158) over 3–6 months. The Ki-67 index and receiving neoadjuvant chemotherapy can affect the engraftment rate in primary patients. The PDX models generated in this study were found to retain the histomorphology, protein expression, and genetic alteration patterns of the original tumors, despite the transcriptomic differences observed. Clinically, the PDX models demonstrated a high degree of similarity with patients in terms of the chemotherapy response and could predict prognosis. Thus, the PDX model can be considered a promising and reliable preclinical tool for personalized and precise treatment.

Carboplatin response in preclinical models for ovarian cancer: comparison of 2D monolayers, spheroids, ex vivo tumors and in vivo models

Epithelial ovarian cancer (EOC) is the most lethal gynecological cancer. Among the key challenges in developing effective therapeutics is the poor translation of preclinical models used in the drug discovery pipeline. This leaves drug attrition rates and costs at an unacceptably high level. Previous work has highlighted the discrepancies in therapeutic response between current in vitro and in vivo models. To address this, we conducted a comparison study to differentiate the carboplatin chemotherapy response across four different model systems including 2D monolayers, 3D spheroids, 3D ex vivo tumors and mouse xenograft models. We used six previously characterized EOC cell lines of varying chemosensitivity and performed viability assays for each model. In vivo results from the mouse model correlated with 2D response in 3/6 cell lines while they correlated with 3D spheroids and the ex vivo model in 4/6 and 5/5 cell lines, respectively. Our results emphasize the variability in therapeutic response across models and demonstrate that the carboplatin response in EOC cell lines cultured in a 3D ex vivo model correlates best with the in vivo response. These results highlight a more feasible, reliable, and cost-effective preclinical model with the highest translational potential for drug screening and prediction studies in EOC.

Precision Medicine Gains Momentum: Novel 3D Models and Stem Cell-Based Approaches in Head and Neck Cancer.

Despite the current progress in the development of new concepts of precision medicine for head and neck squamous cell carcinoma (HNSCC), in particular targeted therapies and immune checkpoint inhibition (CPI), overall survival rates have not improved during the last decades. This is, on the one hand, caused by the fact that a significant number of patients presents with late stage disease at the time of diagnosis, on the other hand HNSCC frequently develop therapeutic resistance. Distinct intratumoral and intertumoral heterogeneity is one of the strongest features in HNSCC and has hindered both the identification of specific biomarkers and the establishment of targeted therapies for this disease so far. To date, there is a paucity of reliable preclinical models, particularly those that can predict responses to immune CPI, as these models require an intact tumor microenvironment (TME). The “ideal” preclinical cancer model is supposed to take both the TME as well as tumor heterogeneity into account. Although HNSCC patients are frequently studied in clinical trials, there is a lack of reliable prognostic biomarkers allowing a better stratification of individuals who might benefit from new concepts of targeted or immunotherapeutic strategies. Emerging evidence indicates that cancer stem cells (CSCs) are highly tumorigenic. Through the process of stemness, epithelial cells acquire an invasive phenotype contributing to metastasis and recurrence. Specific markers for CSC such as CD133 and CD44 expression and ALDH activity help to identify CSC in HNSCC. For the majority of patients, allocation of treatment regimens is simply based on histological diagnosis and on tumor location and disease staging (clinical risk assessments) rather than on specific or individual tumor biology. Hence there is an urgent need for tools to stratify HNSCC patients and pave the way for personalized therapeutic options. This work reviews the current literature on novel approaches in implementing three-dimensional (3D) HNSCC in vitro and in vivo tumor models in the clinical daily routine. Stem-cell based assays will be particularly discussed. Those models are highly anticipated to serve as a preclinical prediction platform for the evaluation of stable biomarkers and for therapeutic efficacy testing.

Waldenströms Macroglobulinemia Cell Lines Display Differential Surface Molecule Expression Reflecting Variability In Disease Biology and Potential Impact Of Therapeutic Stress

BackgroundWaldenstršms Macroglobulinemia (WM) is a lymphoplasmacytic lymphoma that is characterized by immunoglobulin-M (IgM) secreting B-cells that infiltrate the bone marrow, spleen and lymph nodes. The WM tumor compartment displays notable heterogeneity and is comprised of small lymphocytes, plasmacytoid lymphocytes and plasma cells in varying fractions that can be identified by flow cytometry. It has been recently shown that the WM cell profile can shift over time from predominantly monotypic B-lymphocytic cells to a more homogenous plasma cell population in response to treatment with various chemoimmunotherapeutics (Barakat et al, Am J Clin Pathol, 2011). This shift in cell populace is reflected by loss of characteristic B-lymphocyte surface antigens (CD19, CD20) and acquisition/overexpression of plasma cell markers (CD38, CD138), which can be detected by flow cytometry. WM is a relatively rare cancer and there is a corresponding scarcity of reliable preclinical models with only 3 molecularly validated human WM cell lines in existence. Although similar to one another, these human-IgM secreting models, namely BCWM.1 (developed from a newly diagnosed patient), MWCL-1 (developed from a relapsed/refractory patient) and RPCI-WM1 (developed in our laboratory from a highly refractory terminal WM patient) may represent distinct subclasses of WM. We investigated if the clinical variability at the time of development of these models had any phenotypic implications through altered expression of surface proteins. MethodsA comprehensive flow cytometric surface antigen analysis was performed using the BCWM.1, MWCL-1 and RPCI-WM1 cell lines. Surface antigens present on progenitor, immature, activated germinal center and memory B-cells along with those present on plasmablasts and plasma cells were examined. Presence of stem cell markers was also examined. Briefly, antibodies for CD5, 10, 11c, 13, 14, 16, 19, 20, 22, 23, 24, 25, 27, 28, 30, 32, 34, 35, 38, 39, 40, 43, 45, 45RA, 45RO, 52, 54, 56, 62L, 66b, 69, 70, 73, 79b, 80, 86, 90, 101, 105, 110, 111, 117, 123, 127, 133, 134, 135, 137, 138, 154, 184, 197, 202b, 243, 252, 268, 272, 278, 279, 309, 338, FMC7, HLADR, Kappa and Lambda were utilized. Antibodies for determining presence of intracellular CD247, 289, Kappa and Lambda were also used. ResultsWe observed notable differences between the immunophenotypic profiles of RPCI-WM1, BCWM.1 and MWCL-1. These variances are reflective of the dominating malignant B-cell population present at the time in the index patient from whom the cell lines were respectively established. By normalizing the mean fluorescent intensity signals to MESF values, we observed 14 differentially expressed antigens between BCWM.1 and MWCL-1, 23 CD antigens differentially altered between RPCI-WM1 vs. BCWM.1 and 29 surface markers differentially expressed in RPCI-WM1 relative to MWCL-1 cells (MESF fold change >2). Expression of 12 representative antigens across all WM models is shown in Table 1. [Display omitted] ConclusionThis is the first evaluation of the 3 most well established WM models. Our investigation displays important variations in surface protein expression and highlight biological distinction that may develop during the course of WM and/or exposure to therapeutics. This analysis validates that the RPCI-WM1 cell line was derived from a more advanced WM clone with predominantly plasmacytoid features that developed under ongoing therapeutic pressure and is consistent with the clinical phenotype of the index patient (rituximab, bortezomib and chemotherapy resistant). Understanding the significance of the distinct immunophenotypic profiles of existing WM models can (a) further improve the biology of WM, (b) impact of therapeutics on the WM clone and (c) engagement or disengagement of therapeutics targets (as is the case of CD20) during the disease course, which can help guide rational development of therapeutic strategies. Disclosures:No relevant conflicts of interest to declare.

Abstract 2998: Targeting resistance mechanisms in muscle invasive bladder cancer using the chicken egg chorioallantoic membrane patient-derived xenograft model

Abstract Introduction: Non-metastatic muscle invasive urothelial bladder cancer (MIBC) has a poor prognosis and standard of care (SOC) consists of neoadjuvant cisplatin-based chemotherapy (NAC) combined with cystectomy. Patients receiving SOC have at best <10% improvement in five-year overall survival. Residual invasive cancer following NAC has no SOC and has high mortality risk. This major clinical problem underscores gaps in our understanding resistance mechanisms and a need for reliable pre-clinical models. The chicken embryo chorioallantoic membrane (CAM) represents a rapid, scalable, and cost-effective alternative in vivo patient-derived xenograft (PDX) platform. It leverages an easily accessible engraftment scaffold and vascular-rich, immunosuppressed environments for the engraftment of PDX tumors and subsequent functional studies. Our previous proteogenomic data on MIBCs with known chemo-resistant outcomes obtained prior to NAC (pre-NAC) suggests a benefit from treatment with kinase inhibitors (KI). Use of the CAM model in this study aims to address the MIBC pre-clinical model deficit and allow for the rapid screening of therapeutics against NAC-resistant PDXs using selected KI. Methods: We employed the CAM model to expand primary MIBC tumors and tested concordance between cisplatin-based chemotherapy response of patients to matching PDX tumors. We also tested selected KI response on chemotherapy-resistant bladder cancers. PDX growth was assessed by tumor surface area quantification following a week of growth with chemotherapy and KI treatment. Hematoxylin and eosin staining coupled with in situ hybridization, immunohistochemistry for Ki67, and cleaved PARP helped identify tumor cells on the CAM as well as their proliferative and apoptotic indexes. Results: Our initial results show pre-NAC primary MIBC tumors grown on the CAM phenocopy cisplatin-based chemotherapy resistance observed in parent tumor specimens. Histological analysis confirmed engraftment and growth of bladder tumors on the CAM. Patient tumor specimens acquired after chemotherapy treatment (post-NAC) and exhibiting NAC resistance were engrafted successfully on the CAM. Such CAM PDX tumors displayed decreased tumor growth size and proliferation in response to treatment with a dual EGFR and HER2 inhibitor, but had no significant response to either CDK4/6 or FGFR inhibition. Conclusion: Our data suggests concordance between Cisplatin-based chemotherapy resistance phenotypes in primary patient tumors and CAM PDX models. Further, proteogenomic informed KI use on MIBC CAM PDX models suggests a benefit from integration of rapid in vivo testing of novel therapeutics to inform more complex, pre-clinical mouse PDX experiments for more effective clinical trial design aimed at achieving optimal precision medicine for patients with limited treatment options. Citation Format: Hugo Villanueva, Patricia Castro, Andrew G. Sikora, Seth P. Lerner. Targeting resistance mechanisms in muscle invasive bladder cancer using the chicken egg chorioallantoic membrane patient-derived xenograft model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2998.

Conditional Cell Reprogramming in Modeling Digestive System Diseases.

Digestive diseases have become an important source of morbidity and mortality. The considerable financial and health burdens caused by digestive diseases confirm the importance of extensive research to better understand and treat these diseases. The development of reliable preclinical models is essential for understanding the pathogenesis of digestive diseases and developing treatment and prevention methods. However, traditional established cell lines and animal models still have many limitations in the study of the digestive system. Conditional reprogramming (CR) cell culture is a newly developed primary technology that uses irradiated Swiss-3T3-J2 mouse fibroblast cells and the Rho-associated kinase (ROCK) inhibitor Y-27632 to rapidly and efficiently generate many cells from diseased and normal tissues. CR cells (CRCs) can be reprogrammed to maintain a highly proliferative state and recapitulate the histological and genomic features of the original tissue. Moreover, after removing these conditions, the phenotype was completely reversible. Therefore, CR technology may represent an ideal model to study digestive system diseases, to test drug sensitivity, to perform gene profile analysis, and to undertake xenograft research and regenerative medicine. Indeed, together with organoid cultures, CR technology has been recognized as one of the key new technologies by NIH precision oncology and also used for NCI human cancer model initiatives (HCMI) program with ATCC. In this article, we review studies that use CR technology to conduct research on diseases of the digestive system.

Combining species specific in vitro & in silico models to predict in vivo food effect in a preclinical stage – case study of Venetoclax

The pig has been increasingly used as a reliable preclinical model for assessing and predicting the in vivo bioavailability of different formulation strategies. Nevertheless, differences in the composition between porcine and human intestinal fluids, may impact on the solubility and dissolution behaviour of drugs, in particular BCS II/IV drugs. Recently, a porcine fasted simulated intestinal fluid (FaSSIFp) was developed to mimic the composition in the lumen of landrace pigs under fasted state conditions. In this work, we present the utilization of FaSSIFp to compare solubility against human FaSSIF & FeSSIF and further combine species specific in vitro testing with in silico predictive modelling. Venetoclax was chosen as a model drug, representing a BCS class IV drug, with a reported clinically significant positive food effect, where bioavailability is increased up to approximately five-fold when administered with a high-fat meal. Biorelevant species specific in vitro testing was a promising tool for integrating in vitro data into in silico models, using FaSSIFp resulted in reliable predictions of the plasma concentration profile in fasted pigs, based on a porcine physiologically based absorption model. The porcine physiologically based absorption model was used to prospectively simulate the impact of food on the bioavailability of venetoclax. The use of luminal solubility estimates in combination with dissolution data for venetoclax, measured in species specific simulated fluids, correctly predict the observed pig plasma concentration profile and food effect. Overall, integrating species specific in vitro – in silico models led to accurate prediction of in vivo absorption of venetoclax in a preclinical stage, which can support guidance in early decisions of drug product development. In addition, the study further demonstrated the utility of the pig model to predict the food effects of venetoclax in humans.

Abstract PO-052: Exploring patient derived xenografts based pharmacogenomic data for precision oncology

Abstract Preclinical cancer models play a vital role in oncology research and precision medicine. Patient-derived tumor xenografts (PDXs) are used as reliable preclinical models for studying tumor biology and for testing anti-cancer therapies that are tailored according to genomic characteristics of tumors. Several academic groups, research institutes, and commercial organizations are generating and distributing PDX models. However the distributed nature of PDX model generation and lack of central repository make it challenging to find PDX models with specific characteristics. Furthermore this also hinders meta-analysis (across datasets) of PDX pharmacogenomic data. International consortia and catalogs of PDX models such as PDXNet, EurOPDX and PDXFinder are being developed to standardize PDX associated metadata and facilitate material sharing. Recently we have developed Xenograft Visualization & Analysis (Xeva), an open-source software package in R programming language. Xeva allows PDX growth curve visualization, different response metrics computation and biomarker discovery. Extending to this we have developed XevaDB, a database of PDX drug response and genomic profiles. XevaDB is the first resource to allow concurrent visualization of drug response and associated molecular data such as mutation and copy number alterations. Furthermore XevaDB enables exploration of the tumor growth curve of a PDX model, along with corresponding control. XevaDB contains PDXs from >600 individual patients, spanning across nine different tissue types and >70 drugs. Using XevaDB, we have performed meta-analysis of PDX pharmacogenomic data and have identified 90 pathways significantly associated with response to 53 drugs (FDR < 5%). Our results show that activity of the EGFR signaling pathway is significantly associated with erlotinib response in lung cancer PDXs. We have also found that in PDXs, response to binimetinib is associated with the MAP kinase activation pathway. XevaDB provides a comprehensive resource to search and explore PDX pharmacogenomic data. By combining drug response with genomic data of PDXs, XevaDB allows researchers to quickly find the model of interest and access the data to answer their biological questions. As PDXs based pharmacogenomic datasets continue to expand, XevaDB will facilitate easy access and analysis of this valuable data by the scientific community. Citation Format: Arvind Singh Mer, Benjamin Haibe-Kains. Exploring patient derived xenografts based pharmacogenomic data for precision oncology [abstract]. In: Proceedings of the AACR Virtual Special Conference on Artificial Intelligence, Diagnosis, and Imaging; 2021 Jan 13-14. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(5_Suppl):Abstract nr PO-052.

Mouse Models of Peritoneal Carcinomatosis to Develop Clinical Applications.

Simple SummaryPeritoneal carcinomatosis mouse models as a platform to test, improve and/or predict the appropriate therapeutic interventions in patients are crucial to providing medical advances. Here, we overview reported mouse models to explore peritoneal carcinomatosis in translational biomedical research.Peritoneal carcinomatosis of primary tumors originating in gastrointestinal (e.g., colorectal cancer, gastric cancer) or gynecologic (e.g., ovarian cancer) malignancies is a widespread type of tumor dissemination in the peritoneal cavity for which few therapeutic options are available. Therefore, reliable preclinical models are crucial for research and development of efficacious treatments for this condition. To date, a number of animal models have attempted to reproduce as accurately as possible the complexity of the tumor microenvironment of human peritoneal carcinomatosis. These include: Syngeneic tumor cell lines, human xenografts, patient-derived xenografts, genetically induced tumors, and 3D scaffold biomimetics. Each experimental model has its own strengths and limitations, all of which can influence the subsequent translational results concerning anticancer and immunomodulatory drugs under exploration. This review highlights the current status of peritoneal carcinomatosis mouse models for preclinical development of anticancer drugs or immunotherapeutic agents.

Identification of two preclinical canine models of atrial fibrillation to facilitate drug discovery

Atrial fibrillation (AF) is the most common arrhythmia occurring in humans, and new treatment strategies are critically needed. The lack of reliable preclinical animal models of AF is a major limitation to drug development of novel antiarrhythmic compounds. The purpose of this study was to provide a comprehensive head-to-head assessment of 5 canine AF models. Five canine models were evaluated for the efficacy of AF induction and AF duration. We tested 2 acute models: short-term atrial tachypacing (AT) for 6 hours with analysis of AF at hourly increments, and carbachol injection into a cardiac fat pad followed by short-term AT. We also tested 3 chronic models: pacemaker implantation followed by either 4 weeks of AT and subsequent atrial burst pacing or intermittent long-term AT for up to 4-5 months to generate AF ≥4.5 hours, and finally ventricular tachypacing to induce heart failure followed by atrial burst pacing to induce AF. Careful evaluation showed that acute AT, AT for 4 weeks, and the heart failure model all were unsuccessful in generating reproducible AF episodes of sufficient duration to study antiarrhythmic drugs. In contrast, intermittent long-term AT generated AF lasting ≥4.5 hours in ∼30% of animals. The acute model using carbachol and short-term AT resulted in AF induction of ≥15 minutes in ≥75% of animals, thus enabling testing of antiarrhythmic drugs. Intermittent long-term AT and the combination of local carbachol injection with successive short-term AT may contribute to future drug development efforts for AF treatment.

Differential transcriptomics in sarcoidosis lung and lymph node granulomas with comparisons to pathogen-specific granulomas

RationaleDespite the availability of multi-“omics” strategies, insights into the etiology and pathogenesis of sarcoidosis have been elusive. This is partly due to the lack of reliable preclinical models and a paucity of validated biomarkers. As granulomas are a key feature of sarcoidosis, we speculate that direct genomic interrogation of sarcoid tissues, may lead to identification of dysregulated gene pathways or biomarker signatures.ObjectiveTo facilitate the development sarcoidosis genomic biomarkers by gene expression profiling of sarcoidosis granulomas in lung and lymph node tissues (most commonly affected organs) and comparison to infectious granulomas (coccidiodomycosis and tuberculosis).MethodsTranscriptomic profiles of immune-related gene from micro-dissected sarcoidosis granulomas within lung and mediastinal lymph node tissues and compared to infectious granulomas from paraffin-embedded blocks. Differentially-expressed genes (DEGs) were profiled, compared among the three granulomatous diseases and analyzed for functional enrichment pathways.ResultsDespite histologic similarities, DEGs and pathway enrichment markedly differed in sarcoidosis granulomas from lymph nodes and lung. Lymph nodes showed a clear immunological response, whereas a structural regenerative response was observed in lung. Sarcoidosis granuloma gene expression data corroborated previously reported genomic biomarkers (STAB1, HBEGF, and NOTCH4), excluded others and identified new genomic markers present in lung and lymph nodes, ADAMTS1, NPR1 and CXCL2. Comparisons between sarcoidosis and pathogen granulomas identified pathway divergences and commonalities at gene expression level.ConclusionThese findings suggest the importance of tissue and disease-specificity evaluation when exploring sarcoidosis genomic markers. This relevant translational information in sarcoidosis and other two histopathological similar infections provides meaningful specific genomic-derived biomarkers for sarcoidosis diagnosis and prognosis.

Modeling Marginal Zone Lymphomagenesis

Introduction: Indolent B-Cell Non-Hodgkin's Lymphomas (NHL) represent a heterogeneous group of lymphoproliferative malignancies, that remain largely incurable. Marginal zone lymphomas (MZL) are the second most common subtype of indolent NHL, and lack a unique cytogenetic identifying abnormality. The B-cell receptor signaling pathway is activated in B-cell malignancy and mediates its activity mainly through the Phosphoinositide 3-kinase (PI3K) pathway. Furthermore, novel PI3K inhibitors, such as copanlisib and parsaclisib, have shown impressive clinical activity in several indolent lymphomas including MZL. This further supports the important role of the PI3K pathway in the pathogenesis of this tumor. Therefore, we hypothesized that the PI3K-mTOR pathway is sufficient for driving the pathogenesis of MZL. Methods: In order to test our hypothesis, we generated a genetically engineered mouse model carrying heterozygous global knockout alleles of both the tumor suppressor genes Phosphatase and Tensin Homolog (PTEN) and Liver Kinase B1 (LKB1). This led to over-activation of the PI3K-mTOR pathway in all mouse tissues. We closely monitored these mice for tumor formation via weekly physical examinations for several months. Upon tumor detection, the mouse was sacrificed, and tumors were sectioned for histological characterization. In order to generate a more specific model of B cells, and more accurately mimic the underlying human disease, we used the Cre-LoxP system to create the CD19-Cre-PTENfl/fl-LKB1fl/fl. Results: Thirty mice of global KO PTEN+/- LKB1 +/- died or were sacrificed due to disease progression, defined as either lymph node enlargement and/or splenomegaly. All mice showed either abnormal lymphadenopathy or splenomegaly. By Kaplan-Meier analysis, we saw a steady decrease in both tumor-free and overall survival after 3 months of age. Utilizing the product limit method, the median survival time was 6 months (95% CI: 6, 8). A total of 51 lymph nodes were sent for immunohistochemistry and pathological characterization. Of the 51 nodes, 61.5% (N=32) showed indolent Non-Hodgkin's Lymphoma, 25% (N=13) were atypical, and 11.5% (N=6) were reactive. All lymph nodes with indolent NHL were of MZL subtype. Compared to wild type (n=3), the new CD19-Cre-PTENfl/fl -LKB1fl/fl (n=3) showed an overall increase in spleen mass (120 vs 196 mg, p=0.0564), % B1 cells (4% vs 59%, p= 0.0075), % MZ cells (5% vs 30%, p=0.0547), % plasma cells (1% vs 12%, p=0.0729), and decrease in % FO cells (80% vs 12%, p=0.0003) by flowcytometry. Further characterization of the new model is currently underway. Conclusion: Marginal zone lymphoma remains an incurable lymphoma that lacks reliable preclinical models. Our data provides, for the first time, a proof of concept on the role of the PI3K-mTOR pathway in the pathogenesis of marginal zone lymphoma and paves the way for future studies understanding the biology of this disease, and developing rational therapies for this incurable malignancy. Disclosures Yazbeck: Celgene: Consultancy; AstraZeneca: Consultancy; Gilead: Research Funding; Seattle Genetics: Consultancy; Verastem: Speakers Bureau.

MiniPDX-guided postoperative anticancer treatment can effectively prolong the survival of patients with hepatocellular carcinoma.

The recurrence rate of hepatocellular carcinoma (HCC) after partial hepatectomy is still high. How to choose the most appropriate anti-tumor drug in the early postoperative period is crucial to improve the prognosis of patients. Recently, MiniPDX has been widely used as a new and reliable preclinical research model capable of predicting the sensitivities of anti-tumor drugs. Twenty-eight patients with HCC were selected to use the MiniPDX model to screen the most sensitive anti-tumor drugs from five groups of drug regimens for preventive treatment after partial hepatectomy, and another 42 patients with HCC were selected to be treated with Sorafenib during the same period as the control group. The tumor-free survival rate and overall survival rate were analyzed and compared between these two groups. The relationship between drug sensitivity and biomarkers related to HCC was also analyzed. Kaplan-Meier survival curve analysis showed that the tumor-free survival (DFS) of patients in the MiniPDX group was significantly longer than that in the control group (median DFS: 25.8months vs. 18.2months, P = 0.022, HR 2.19, 95% CI 1.17-4.12). The overall survival (OS) of the patients in the MiniPDX group was also longer than that in the control group (median OS: 29.4months vs. 23.8months, P = 0.039, HR 2.37, 95% CI 1.12-5.00). The longest follow-up period was 36months. The relationship analyzed between the efficacy of the five drugs (Regorafenib, Regorafenib, Lenvatinib, Gemcitabine, 5-FU + Oxaliplatin) and AFP, Ki-67, VEGFR, FGFR, P53, and Nrf2 showed different correlations. The use of the MiniPDX model to select drugs to guide anti-tumor treatment after partial hepatectomy could effectively prolong the survival of patients with HCC.

Analysis of the influence of species, intervertebral disc height and Pfirrmann classification on failure load of an injured disc using a novel disc herniation model

Background ContextAnnular repair devices offer a solution to recurrent disc herniations by closing an annular defect and lowering the risk of reherniation. Given the significant risk of neurologic injury from device failure it is imperative that a reliable preclinical model exists to demonstrate a high load to failure for the disc repair devices. PurposeTo establish a preclinical model for disc herniation and demonstrate how changes in species, intervertebral disc height and Pfirrmann classification impacts failure load on an injured disc. We hypothesized that: (1) The force required for disc herniation would be variable across disc morphologies and species, and (2) for human discs the force to herniation would inversely correlate with the degree of disc degeneration. Study designAnimal and human cadaveric biomechanical model of disc herniation. MethodsWe tested calf lumbar spines, bovine tail segments and human lumbar spines. We first divided individual lumbar or tail segments to include the vertebral bodies and disc. We then hydrated the specimens by placing them in a saline bath overnight. A magnetic resonance images were acquired from human specimens and a Pfirrmann classification was made. A stab incision measuring 25% of the diameter of the disc was then done to each specimen along the posterior intervertebral disc space. Each specimen was placed in custom test fixtures on a servo-hydraulic test frame (MTS, Eden Prarie, MN) such that the superior body was attached to a 10,000 lb load cell and the inferior body was supported on the piston. A compressive ramping load was placed on the specimen in load control at 4 MPa/sec stopping at 75% of the disc height. Load was recorded throughout the test and failure load calculated. Once the test was completed each specimen was sliced through the center of the disc and photos were taken of the cut surface. ResultsFifteen each of calf, human, and bovine tail segments were tested. The failure load varied significantly between specimens (p<.001) with human specimens having the highest average failure load (8154±2049 N). Disc height was higher for lumbar/bovine tail segments as compared to calf specimens (p<.001) with bovine tails having the highest disc height (7.1±1.7 mm). Similarly, human lumbar discs had a cross sectional area that was greater than both bovine tail/calf lumbar spines (p<.001). There was no correlation between disc height and failure load within each individual species (p>.05). Cross sectional area and failure load did not correlate with failure load for human lumbar spine and bovine tails (p>.05) but did correlate with calf spine (r=0.53, p=.04). There was a statistically significant inverse correlation between disc height and Pfirrmann classification for human lumbar spines (r=−0.84, p<.001). There was also a statistically significant inverse relationship between Pfirrmann classification and failure load (r=−0.58, p=.02). ConclusionsWe have established a model for disc herniation and have shown how results of this model vary between species, disc morphology, and Pfirrmann classification. Both hypotheses were accepted: The force required for disc herniation was variable across species, and the force to herniation for human spines was inversely correlated with the degree of disc degeneration. We recommend that models using human intervertebral discs should include data on Pfirrmann classification, while biomechanical models using calf spines should report cross sectional area. Failure loads do not vary based on dimensions for bovine tails. Clinical SignificanceOur analysis of models for disc herniation will allow for quicker, reliable comparisons of failure forces required to induce a disc herniation. Future work with these models may facilitate rapid testing of devices to repair a torn/ruptured annulus.