Cellular Therapies for the Treatment of Hematological Malignancies; Swine Are an Ideal Preclinical Model

Establishment of Transgene-Free Porcine Induced Pluripotent Stem Cells

Although protocols to generate authentic transgene-free mouse and human induced pluripotent stem cells (iPSCs) are now well established, standard methods for reprogramming porcine somatic cells still suffer from low efficiency and transgene retention. The Basic Protocol describes reprogramming procedures to establish transgene-free porcine iPSCs (PiPSCs) from porcine fibroblasts. This method uses episomal plasmids encoding POU5F1, SOX2, NANOG, KLF4, SV40LT, c-MYC, LIN28A, and microRNA-302/367, combined with an optimized medium, to establish PiPSC lines. Support protocols describe the establishment and characterization of clonal PiPSC lines, as well as the preparation of feeder cells and EBNA1 mRNA. This optimized, step-by-step approach tailored to this species enables the efficient derivation of PiPSCs in ∼4 weeks. The establishment of transgene-free PiPSCs provides a new and valuable model for studies of larger mammalian species' development, disease, and regenerative biology. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Reprogramming of porcine fibroblasts with episomal plasmids Support Protocol 1: Preparation of mouse embryonic fibroblasts for feeder layer Support Protocol 2: Preparation of in vitro-transcribed EBNA1 mRNA Support Protocol 3: Establishment of clonal porcine induced pluripotent stem cell (PiPSC) lines Support Protocol 4: PiPSC characterization: Genomic DNA PCR and RT-PCR Support Protocol 5: PiPSC characterization: Immunostaining.

Epstein-Barr Virus-Encoded BILF1 Orthologues From Porcine Lymphotropic Herpesviruses Display Common Molecular Functionality

Infection of immunosuppressed transplant patients with the human γ-herpesvirus Epstein-Barr virus (EBV) is associated with post-transplant lymphoproliferative disease (PTLD), an often fatal complication. Immunosuppressed miniature pigs infected with γ-herpesvirus porcine lymphotropic herpesvirus 1 (PLHV1) develop a similar disease, identifying pigs as a potential preclinical model for PTLD in humans. BILF1 is a G protein-coupled receptor (GPCR) encoded by EBV with constitutive activity linked to tumorigenesis and immunoevasive function downregulating MHC-I. In the present study, we compared BILF1-orthologues encoded by the three known PLHVs (PLHV1-3) with EBV-BILF1 to determine pharmacological suitability of BILF1 orthologues as model system to study EBV-BILF1 druggability. Cell surface localization, constitutive internalization, and MHC-I downregulation as well as membrane proximal constitutive Gα_i signaling patterns were conserved across all BILFs. Only subtle differences between the individual BILFs were observed in downstream transcription factor activation. Using Illumina sequencing, PLHV1 was observed in lymphatic tissue from PTLD-diseased, but not non-diseased pigs. Importantly, these tissues showed enhanced expression of PLHV1-BILF1 supporting its involvement in PTLD infection.

Transarterial Embolization of Liver Cancer in a Transgenic Pig Model

PURPOSE

To develop and characterize a porcine model of liver cancer that could be used to test new locoregional therapies.

MATERIALS AND METHODS

Liver tumors were induced in 18 Oncopigs (transgenic pigs with Cre-inducible TP53^R167H and KRAS^G12D mutations) by using an adenoviral vector encoding the Cre-recombinase gene. The resulting 60 tumors were characterized on multiphase contrast-enhanced CT, angiography, perfusion, micro-CT, and necropsy. Transarterial embolization was performed using 40-120 μm (4 pigs) or 100-300 μm (4 pigs) Embosphere microspheres. Response to embolization was evaluated on imaging. Complications were determined based on daily clinical evaluation, laboratory results, imaging, and necropsy.

RESULTS

Liver tumors developed at 60/70 (86%) inoculated sites. Mean tumor size was 2.1 cm (range, 0.3-4 cm) at 1 week. Microscopically, all animals developed poorly differentiated to undifferentiated carcinomas accompanied by a major inflammatory component, which resembled undifferentiated carcinomas of the human pancreatobiliary tract. Cytokeratin and vimentin expression confirmed epithelioid and mesenchymal differentiation, respectively. Lymph node, lung, and peritoneal metastases were seen in some cases. On multiphase CT, all tumors had a hypovascular center, and 17/60 (28%) had a hypervascular rim. After transarterial embolization, noncontrast CT showed retained contrast medium in the tumors. Follow-up contrast-enhanced scan showed reduced size of tumors after embolization using either 40-120 μm or 100-300 μm Embosphere microspheres, while untreated tumors showed continued growth.

CONCLUSIONS

Liver tumors can be induced in a transgenic pig and can be successfully treated using bland embolization.

Improving human cancer therapy through the evaluation of pet dogs

Comparative oncology clinical trials play an important and growing role in cancer research and drug development efforts. These trials, typically conducted in companion (pet) dogs, allow assessment of novel anticancer agents and combination therapies in a veterinary clinical setting that supports serial biologic sample collections and exploration of dose, schedule and corresponding pharmacokinetic/pharmacodynamic relationships. Further, an intact immune system and natural co-evolution of tumour and microenvironment support exploration of novel immunotherapeutic strategies. Substantial improvements in our collective understanding of the molecular landscape of canine cancers have occurred in the past 10 years, facilitating translational research and supporting the inclusion of comparative studies in drug development. The value of the approach is demonstrated in various clinical trial settings, including single-agent or combination response rates, inhibition of metastatic progression and randomized comparison of multiple agents in a head-to-head fashion. Such comparative oncology studies have been purposefully included in the developmental plan for several US FDA-approved and up-and-coming anticancer drugs. Challenges for this field include keeping pace with technology and data dissemination/harmonization, improving annotation of the canine genome and immune system, and generation of canine-specific validated reagents to support integration of correlative biology within clinical trial efforts.

Beyond tradition and convention: benefits of non-traditional model organisms in cancer research

Traditional laboratory model organisms are indispensable for cancer research and have provided insight into numerous mechanisms that contribute to cancer development and progression in humans. However, these models do have some limitations, most notably related to successful drug translation, because traditional model organisms are often short-lived, small-bodied, genetically homogeneous, often immunocompromised, are not exposed to natural environments shared with humans, and usually do not develop cancer spontaneously. We propose that assimilating information from a variety of long-lived, large, genetically diverse, and immunocompetent species that live in natural environments and do develop cancer spontaneously (or do not develop cancer at all) will lead to a more comprehensive understanding of human cancers. These non-traditional model organisms can also serve as sentinels for environmental risk factors that contribute to human cancers. Ultimately, expanding the range of animal models that can be used to study cancer will lead to improved insights into cancer development, progression and metastasis, tumor microenvironment, as well as improved therapies and diagnostics, and will consequently reduce the negative impacts of the wide variety of cancers afflicting humans overall.

Porcine cancer models: potential tools to enhance cancer drug trials

INTRODUCTION

The amount of time and money invested into cancer drug research, development, and clinical trials has continually increased over the past few decades. Despite record high cancer drug approval rates, cancer remains a leading cause of death. This suggests the need for more effective tools to help bring novel therapies to clinical practice in a timely manner.

AREAS COVERED

In this review, current issues associated with clinical trials are discussed, specifically focusing on poor accrual rates and time for trial completion. In addition, details regarding preclinical studies required before advancing to clinical trials are discussed, including advantages and limitations of current preclinical animal cancer models and their relevance to human cancer trials. Finally, new translational porcine cancer models (Oncopig Cancer Model (OCM)) are presented as potential co-clinical trial models.

EXPERT OPINION

In order to address issues impacting the poor success rate of oncology clinical trials, we propose the incorporation of the transformative OCM 'co-clinical trial' pathway into the cancer drug approval process. Due to the Oncopig's high homology to humans and similar tumor phenotypes, their utilization can provide improved preclinical prediction of both drug safety and efficacy prior to investing significant time and money in human clinical trials.

GABA attenuates ETEC-induced intestinal epithelial cell apoptosis involving GABAAR signaling and the AMPK-autophagy pathway

Enterotoxigenic Escherichia coli (ETEC) triggers diarrhea in humans and livestock. We have previously showed that ETEC promotes intestinal epithelial cell apoptosis and increases gamma-aminobutyric acid (GABA) concentration in the jejunum, suggesting that GABA might mediate ETEC-induced apoptosis. Here, we found that GABA alleviates ETEC-induced intestinal barrier dysfunctions, including ETEC-induced apoptosis both in vivo and in vitro. Interestingly, the alleviation of GABA on ETEC-induced apoptosis largely depends on autophagy. Mechanistically, GABA attenuates ETEC-induced apoptosis via activating GABA_AR signaling and the AMPK-autophagy pathway. These findings highlight that maintaining intestinal GABA concentration could alleviate intestinal ETEC infection.