Evaluation of the DLL3-targeting antibody-drug conjugate rovalpituzumab tesirine in preclinical models of neuroblastoma.

Neuroblastomas have neuroendocrine features and often show similar gene expression patterns to small cell lung cancer including high expression of delta-like ligand 3 (). Here we determine the efficacy of rovalpituzumab tesirine (Rova-T), an antibody drug conjugated (ADC) with a pyrrolobenzodiazepine (PBD) dimer toxin targeting DLL3, in preclinical models of human neuroblastoma. We evaluated DLL3 expression in RNA sequencing data sets and performed immunohistochemistry (IHC) on neuroblastoma patient derived xenograft (PDX), human neuroblastoma primary tumor and normal childhood tissue microarrays (TMAs).

ABBV-011, A Novel, Calicheamicin-Based Antibody-Drug Conjugate, Targets SEZ6 to Eradicate Small Cell Lung Cancer Tumors.

In the past year, four antibody-drug conjugates (ADC) were approved, nearly doubling the marketed ADCs in oncology. Among other attributes, successful ADCs optimize targeting antibody, conjugation chemistry, and payload mechanism of action. Here, we describe the development of ABBV-011, a novel SEZ6-targeted, calicheamicin-based ADC for the treatment of small cell lung cancer (SCLC).

Delta-Like Protein 3 Expression and Targeting in Merkel Cell Carcinoma.

Purpose: Delta-like protein 3 (DLL3) is being developed as a predictive biomarker for DLL3-targeting antibody-drug conjugate and other therapies. Given the neuroendocrine features of Merkel cell carcinoma (MCC), we sought to evaluate DLL3 expression and its role in MCC.

Experimental Design: Formalin-fixed and paraffin-embedded MCC cases were consecutively selected.

Delta-like protein 3 expression and therapeutic targeting in neuroendocrine prostate cancer.

Histologic transformation to small cell neuroendocrine prostate cancer occurs in a subset of patients with advanced prostate cancer as a mechanism of treatment resistance. Rovalpituzumab tesirine (SC16LD6.5) is an antibody-drug conjugate that targets delta-like protein 3 (DLL3) and was initially developed for small cell lung cancer.

Cell Surface Notch Ligand DLL3 is a Therapeutic Target in Isocitrate Dehydrogenase-mutant Glioma.

Purpose: Isocitrate dehydrogenase ()-mutant glioma is a distinct glioma molecular subtype for which no effective molecularly directed therapy exists. Low-grade gliomas, which are 80%-90% -mutant, have high RNA levels of the cell surface Notch ligand DLL3. We sought to determine DLL3 expression by IHC in glioma molecular subtypes and the potential efficacy of an anti-DLL3 antibody-drug conjugate (ADC), rovalpituzumab tesirine (Rova-T), in -mutant glioma.

Transcriptomic and Protein Analysis of Small-cell Bladder Cancer (SCBC) Identifies Prognostic Biomarkers and DLL3 as a Relevant Therapeutic Target.

Purpose: Transcriptomic profiling can shed light on the biology of small-cell bladder cancer (SCBC), nominating biomarkers, and novel therapeutic targets.

Experimental Design: Sixty-three patients with SCBC had small-cell histology confirmed and quantified by a genitourinary pathologist. Gene expression profiling was performed for 39 primary tumor samples, 1 metastatic sample, and 6 adjacent normal urothelium samples (46 total) from the same cohort.

Prevalence of Delta-like protein 3 expression in patients with small cell lung cancer.

Objectives: Rovalpituzumab tesirine (Rova-T), an antibody-drug conjugate directed against Delta-like protein 3 (DLL3), is under development for patients with small cell lung cancer (SCLC) positive for this protein. However, the prevalence of DLL3 expression and its association with patient ethnicity and other characteristics have remained unclear.

Materiais And Methods: Tumor samples from 63 patients with SCLC were subjected to immunohistochemical staining for DLL3.

Noninvasive Interrogation of DLL3 Expression in Metastatic Small Cell Lung Cancer.

The Notch ligand DLL3 has emerged as a novel therapeutic target expressed in small cell lung cancer (SCLC) and high-grade neuroendocrine carcinomas. Rovalpituzumab teserine (Rova-T; SC16LD6.5) is a first-in-class DLL3-targeted antibody-drug conjugate with encouraging initial safety and efficacy profiles in SCLC in the clinic.

Tissue-type plasminogen activator suppresses activated stellate cells through low-density lipoprotein receptor-related protein 1.

Hepatic stellate cell (HSC) activation and trans-differentiation into myofibroblast (MFB)-like cells is key for fibrogenesis after liver injury and a potential therapeutic target. Recent studies demonstrated that low-density lipoprotein receptor-related protein 1 (LRP1)-dependent signaling by tissue-type plasminogen activator (t-PA) is a pro-fibrotic regulator of the MFB phenotype in kidney. This study investigated whether LRP1 signaling by t-PA is also relevant to HSC activation following injury.

IRF-1 promotes liver transplant ischemia/reperfusion injury via hepatocyte IL-15/IL-15Rα production.

Ischemia and reperfusion (I/R) injury following liver transplantation (LTx) is an important problem that significantly impacts clinical outcomes. IFN regulatory factor-1 (IRF-1) is a nuclear transcription factor that plays a critical role in liver injury. Our objective was to determine the immunomodulatory role of IRF-1 during I/R injury following allogeneic LTx.

Breast tumor kinase/protein tyrosine kinase 6 (Brk/PTK6) activity in normal and neoplastic biliary epithelia.

Background & Aims: Breast tumor kinase (BRK) augments proliferation and promotes cell survival in breast cancers via interactions with SH2 and SH3 ligand-containing proteins, such as receptor tyrosine kinases (RTK; e.g. EGFR, ErbB2/neu).

CD39 deficiency in murine liver allografts promotes inflammatory injury and immune-mediated rejection.

Adenosine triphosphate (ATP), an essential metabolic energy source, is released following cell apoptosis or necrosis. It acts as a damage-associated molecule pattern to stimulate innate immune cells. The ectonucleotidase CD39 regulates immune activation by hydrolysis of extracellular ATP.

Acute liver allograft antibody-mediated rejection: an inter-institutional study of significant histopathological features.

Acute antibody-mediated rejection (AMR) occurs in a small minority of sensitized liver transplant recipients. Although histopathological characteristics have been described, specific features that could be used (1) to make a generalizable scoring system and (2) to trigger a more in-depth analysis are needed to screen for this rare but important finding. Toward this goal, we created training and validation cohorts of putative acute AMR and control cases from 3 high-volume liver transplant programs; these cases were evaluated blindly by 4 independent transplant pathologists.

Optimal lung inflation techniques in a rat lung transplantation model: a revisit.

Background: Most of the experimental work assessing optimal lung inflation during lung graft preservation was performed in the late 1990s. Since that time, lung preservation before transplantation has been more standardized, and the optimal lung inflation techniques used during lung preservation in the current clinical setting remain undefined. Nonetheless, lung inflation during storage may play a pivotal role in optimal lung preservation.

Low TCR signal strength induces combined expansion of Th2 and regulatory T cell populations that protect mice from the development of type 1 diabetes.

Aims/hypothesis: Weak stimulation of CD4(+) T cells induces expansion of CD4(+) forkhead box P3(+) regulatory T cells (Tregs) and can also promote T helper (Th) 2 responses, which have demonstrable beneficial effects on autoimmune diabetes. This study explored the feasibility of combined Treg/Th2 expansion for immunotherapy of type 1 diabetes in NOD mice.

Methods: We compared Treg and Th responses to dendritic cells (DC) presenting scaled antigen doses to islet-specific NOD CD4(+) T cells.

Distribution of non-gal antigens in pig cornea: relevance to corneal xenotransplantation.

Purpose: The aim of this study was to investigate the distribution of antigens other than galactose-α-1,3-galactose (Gal) (non-Gal) recognized by human and rhesus monkey serum antibodies in the α-1,3-galactosyltransferase gene-knockout (GTKO) pig cornea.

Methods: The distribution of non-Gal, specifically N-glycolylneuraminic acid (NeuGc), in the corneas from wild-type (WT) and GTKO pigs was identified. Corneal sections from WT and GTKO pigs were incubated with human or rhesus monkey serum to determine immunoglobulin (Ig)M and IgG binding to corneal tissue by means of fluorescent microscopy.

Increased soluble CD154 (CD40 ligand) levels in xenograft recipients correlate with the development of de novo anti-pig IgG antibodies.

Background: De novo anti-pig antibodies are associated with acute humoral xenograft rejection. We explored the relative efficacy of CD40/CD154-pathway blockade versus CD28/B7-pathway blockade in the prevention of de novo anti-pig IgG antibodies in xenograft recipients.

Methods: After α1,3-galactosyltransferase gene-knockout pig artery patch xenotransplantation, recipient baboons received no immunosuppression (IS; n=3), or anti-CD154mAb-based (n=5) or CTLA4-Ig-based (n=5) IS.

Small proline rich protein 2a in benign and malignant liver disease.

Unlabelled: STAT3-driven expression of small proline rich protein 2a (SPRR2a), which acts as an src homology 3 (SH3) domain ligand, induces biliary epithelial cell (BEC) epithelial-mesenchymal transition (EMT), which, in turn, promotes wound healing. SPRR2a also quenches free radicals and protects against oxidative stress and DNA damage in nonneoplastic BEC. Sprr2a-induced EMT also increases local invasiveness of cholangiocarcinomas (CC), but prevents metastases.

SPRR2A expression in cholangiocarcinoma increases local tumor invasiveness but prevents metastasis.

Cholangiocarcinoma morbidity and mortality is attributable to local invasiveness and regional lymph node and distant organ metastasis. Cholangiocarcinoma progression follows a series of sequential events that resemble wound healing reactions: local invasion resembles the epithelial migration phase involving epithelial-mesenchymal transition (EMT); colonization at distant sites resembles epithelial restitution seen during the reverse process, mesenchymal-epithelial transition (MET). In this study we compare the in vivo local and metastatic growth potential of cholangiocarcinoma cell lines with respect to expression of a novel pSTAT3-dependent, biliary epithelial cell wound healing protein, small proline-rich protein 2A (SPRR2A).

Tissue biopsy monitoring of operational tolerance in liver allograft recipients.

Purpose Of Review: Highly selected, long-surviving, liver allograft recipients with normal/near normal liver injury tests can be weaned from immunosuppression. Baseline biopsies document changes before weaning and can help stratify risk of rejection or dysfunction after weaning; biopsies after weaning are used to study mechanisms of operational tolerance and to monitor for subclinical events.

Recent Findings: Clinicopathological features associated with successful weaning include a lack of sensitization [negative donor-specific antibodies (DSA) and lack of tissue C4d deposits]; 'inexperienced' recipient immune system with limited potential for cross-reactivity (less immunological memory; infant recipients); noninflamed allograft in those with nonviral, nonimmunological original diseases; upregulation of liver genes associated with iron metabolism; allograft colonization with 'immunosuppressive' cells (Treg and γδ-1>γδ-2); and longer time on immunosuppression, which might signal slow clonal deletion or silencing.

Human dominant-negative class II transactivator transgenic pigs - effect on the human anti-pig T-cell immune response and immune status.

Swine leucocyte antigen (SLA) class II molecules on porcine (p) cells play a crucial role in xenotransplantation as activators of recipient human CD4(+) T cells. A human dominant-negative mutant class II transactivator (CIITA-DN) transgene under a CAG promoter with an endothelium-specific Tie2 enhancer was constructed. CIITA-DN transgenic pigs were produced by nuclear transfer/embryo transfer.

Gut bacteria drive Kupffer cell expansion via MAMP-mediated ICAM-1 induction on sinusoidal endothelium and influence preservation-reperfusion injury after orthotopic liver transplantation.

Bacteria in the gut microbiome shed microbial-associated molecule patterns (MAMPs) into the portal venous circulation, where they augment various aspects of systemic immunity via low-level stimulation. Because the liver is immediately downstream of the intestines, we proposed that gut-derived MAMPs shape liver immunity and affect Kupffer cell (KC) phenotype. Germ-free (GF), antibiotic-treated (AVMN), and conventional (CL) mice were used to study KC development, function, and response to the significant stress of cold storage, reperfusion, and orthotopic transplantation.

Preexisting epithelial diversity in normal human livers: a tissue-tethered cytometric analysis in portal/periportal epithelial cells.

Unlabelled: Routine light microscopy identifies two distinct epithelial cell populations in normal human livers: hepatocytes and biliary epithelial cells (BECs). Considerable epithelial diversity, however, arises during disease states when a variety of hepatocyte-BEC hybrid cells appear. This has been attributed to activation and differentiation of putative hepatic progenitor cells (HPC) residing in the canals of Hering and/or metaplasia of preexisting mature epithelial cells.

Profiling molecular changes induced by hydrogen treatment of lung allografts prior to procurement.

Background: We previously demonstrated that donor treatment with inhaled hydrogen protects lung grafts from cold ischemia/reperfusion (I/R) injury during lung transplantation. To elucidate the mechanisms underlying hydrogen's protective effects, we conducted a gene array analysis to identify changes in gene expression associated with hydrogen treatment.

Methods: Donor rats were exposed to mechanical ventilation with 98% oxygen and 2% nitrogen or 2% hydrogen for 3 h before harvest; lung grafts were stored for 4h in cold Perfadex.

SPRR2A enhances p53 deacetylation through HDAC1 and down regulates p21 promoter activity.

Background: Small proline rich protein (SPRR) 2A is one of 14 SPRR genes that encodes for a skin cross-linking protein, which confers structural integrity to the cornified keratinocyte cell envelope. New evidence, however, shows that SPRR2A is also a critical stress and wound repair modulator: it enables a variety of barrier epithelia to transiently acquire mesenchymal characteristics (EMT) and simultaneously quench reactive oxygen species during wound repair responses. p53 is also widely recognized as the node in cellular stress responses that inhibits EMT and triggers cell-cycle arrest, apoptosis, and cellular senescence.