Tumor-specific T cells in head and neck cancer have rescuable functionality and can be identified through single-cell co-culture

BACKGROUND

Human papillomavirus (HPV)-negative head and neck squamous cell carcinoma (HNSCC) remains a treatment-resistance disease with limited response to immunotherapy. While T cells in HNSCC are known to display phenotypic dysfunction, whether they retain rescuable functional capacity and tumor-killing capability remains unclear.

METHODS

To investigate the functionality and tumor-specificity of tumor-infiltrating lymphocytes (TILs) across HNSCCs, malignant cell lines and TILs were derived from 31 HPV-negative HNSCCs at the time of standard surgical resection. T cell functional capacity was evaluated through ex vivo expansion, immunophenotyping, and IsoLight single-cell proteomics. Tumor-specificity was investigated through both bulk and single-cell tumor-TIL co-culture.

RESULTS

TILs could be successfully generated from 24 patients (77%), including both previously untreated and radiation recurrent HNSCCs. We demonstrate that across HNSCCs, TILs express multiple exhaustion markers but maintain a predominantly effector memory phenotype. After ex vivo expansion, TILs retain immunogenic functionality even from radiation-resistant, exhausted, and T cell-depleted disease. We further demonstrate tumor-specificity of T cells across HNSCC patients through patient-matched malignant cell-T cell co-culture. Finally, we use optofluidic technology to establish an autologous single tumor cell-single T cell co-culture platform for HNSCC. Cells derived from three HNSCC patients underwent single-cell co-culture which enabled identification and visualization of individual tumor-killing TILs in real-time in all patients.

CONCLUSIONS

These studies show that cancer-specific T cells exist across HNSCC patients with rescuable immunogenicity and can be identified on a single-cell level. These data lay the foundation for development of patient-specific T cell immunotherapies in HNSCC.

Photoactivated HPPH-Liposomal therapy for the treatment of HPV-Negative head and neck cancer

OBJECTIVES

Human Papillomavirus (HPV)-negative head and neck cancer (HNC) is an aggressive malignancy with a poor prognosis. To improve outcomes, we developed a novel liposomal targeting system embedded with 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a (HPPH), a chlorin-based photosensitizer. Upon exposure to 660 nm light, HPPH phototriggering generates reactive oxygen species. The objective of this study was to evaluate biodistribution and test efficacy of HPPH-liposomal therapy in a patient-derived xenograft (PDX) model of chemoradioresistant HNC.

MATERIALS AND METHODS

PDX models were developed from two surgically resected HNCs (P033 and P038) recurrent after chemoradiation. HPPH-liposomes were created including trace amounts of DiR (Ex/Em 785/830 nm), a near infrared lipid probe. Liposomes were injected via tail vein into PDX models. Biodistribution was assessed at serial timepoints in tumor and end-organs through in vivo DiR fluorescence. To evaluate efficacy, tumors were treated with a cw-diode 660 nm laser (90 mW/cm2, 5 min). This experimental arm was compared to appropriate controls, including HPPH-liposomes without laser or vehicle with laser alone.

RESULTS

HPPH-liposomes delivered via tail vein exhibited selective tumor penetration, with a peak concentration at 4 h. No systemic toxicity was observed. Treatment with combined HPPH-liposomes and laser resulted in improved tumor control relative to either vehicle or laser alone. Histologically, this manifested as both increased cellular necrosis and decreased Ki-67 staining in the tumors treated with combined therapy.

CONCLUSIONS

These data demonstrate tumor-specific anti-neoplastic efficacy of HPPH-liposomal treatment for HNC. Importantly, this platform can be leveraged in future studies for targeted delivery of immunotherapies which can be packaged within HPPH-liposomes.

Defective collagen binding and increased bleeding in a murine model of von Willebrand disease affecting collagen IV binding

Essentials Defective binding to collagen IV has been seen in von Willebrand factor (VWF) A1 domain variants. We developed a murine model of defective VWF-collagen IV interactions with VWF variant p.R1399H. p.1399HH homozygous mice had decreased binding to collagen IV and increased bleeding times. p.1399HH homozygous mice had increased time to thrombosis and decreased platelet adhesion. SUMMARY: Background von Willebrand factor (VWF) binding to type IV collagen occurs via the VWF A1 domain, with p.R1399H being the most common VWF variant affecting this interaction. Objectives We generated a murine model of 1399H VWF to investigate its in vivo effects. Methods Mice expressing the murine 1399H variant were generated via gene targeting in embryonic stem cells. VWF antigen and VWF collagen binding were measured with ELISA. Tail bleeding time assays were performed by clipping a 3-mm segment. Ferric chloride-induced thrombosis was measured via ultrasound in the carotid artery. Platelet aggregation in response to collagens I and IV was measured. VWF-dependent platelet adhesion to collagen IV was measured under flow. Results Breeding of heterozygous p.R1399H and homozygous p.1399HH mice was observed to follow normal Mendelian ratios. No spontaneous bleeding was observed for any of the offspring. VWF expression was normal, but VWF binding to collagen IV was decreased in both heterozygous and homozygous offspring. Blood loss following tail resection was increased for p.1399HH mice, and occlusion times following ferric chloride-induced thrombosis were prolonged. Platelet aggregation was unaffected, but platelet adhesion to collagen IV under flow was diminished for p.1399HH mice. Conclusions These results show that a decrease in the ability of 1399H VWF to bind collagen IV under static conditions corresponds to a decrease in binding under flow conditions, an increased bleeding time, and a prolonged time to thrombosis. This study supports the potential for a bleeding phenotype in patients with aberrant VWF-collagen IV binding.

Abstract P292: Gene Editing Rat Resource Center: Rat Models for Heart, Lung, Blood, and Sleep Disorder Studies

Transgenesis and gene editing in the rat has produced gene-modified strains which can be used to validate a gene underlying a quantitative trait locus or human association, or to design follow up studies to define function and physiological roles of genes or sequence variants. We are currently in the fifth year of developing rat models for investigators to validate human variation and study function and mechanism for genes implicated in heart, lung and blood disorders. The Gene Editing Rat Resource Center (GERRC, http://rgd.mcw.edu/wg/custom_rats/gerrc ) is an NHLBI-funded R24 resource program to generate, distribute, and cryopreserve novel rat models to the research community. Investigator-initiated applications to produce novel genetically modified rat strains were received from laboratories across the world and reviewed by an external advisory board for scientific merit and potential broad interest to the heart, lung, blood, and sleep disorder research community. Custom knockout, knockin, and transgenic rat models continue to be developed. To date, we have transferred over 19,570 microinjected embryos, resulting in 4000+ live-born pups of which 3400+ have been screened for transgenesis or mutagenesis of the target gene. Of these, we have successfully generated ~630 pups containing transgenes or targeted mutations in 95 genes, distributed among 16 inbred, outbred, consomic and congenic rat strains frequently used in cardiovascular research. After confirming germline transmission, heterozygous breeders are distributed to the requesting investigator and then each model is made available to the rat research community. Sperm is cryopreserved to maintain a permanent source of these models. Collectively, the GERRC resource represents the largest collection of genetically modified rat models which are distributable to any investigator through a standard materials transfer agreement at the cost of rearing and shipping. We will discuss the general progress of genetic engineering in rats, current challenges for the field, and opportunities for future developments.

Nogo-B receptor deficiency increases liver X receptor alpha nuclear translocation and hepatic lipogenesis through an adenosine monophosphate-activated protein kinase alpha-dependent pathway

Nogo-B receptor (NgBR) was identified as a specific receptor for binding Nogo-B and is essential for the stability of Niemann-Pick type C2 protein (NPC2) and NPC2-dependent cholesterol trafficking. Here, we report that NgBR expression levels decrease in the fatty liver and that NgBR plays previously unrecognized roles in regulating hepatic lipogenesis through NPC2-independent pathways. To further elucidate the pathophysiological role of NgBR in mammals, we generated NgBR liver-specific knockout mice and investigated the roles of NgBR in hepatic lipid homeostasis. The results showed that NgBR knockout in mouse liver did not decrease NPC2 levels or increase NPC2-dependent intracellular cholesterol levels. However, NgBR deficiency still resulted in remarkable cellular lipid accumulation that was associated with increased free fatty acids and triglycerides in hepatocytes in vitro and in mouse livers in vivo. Mechanistically, NgBR deficiency specifically promotes the nuclear translocation of the liver X receptor alpha (LXRα) and increases the expression of LXRα-targeted lipogenic genes. LXRα knockout attenuates the accumulation of free fatty acids and triglycerides caused by NgBR deficiency. In addition, we elucidated the mechanisms by which NgBR bridges the adenosine monophosphate-activated protein kinase alpha signaling pathway with LXRα nuclear translocation and LXRα-mediated lipogenesis.

CONCLUSION

NgBR is a specific negative regulator for LXRα-dependent hepatic lipogenesis. Loss of NgBR may be a potential trigger for inducing hepatic steatosis. (Hepatology 2016;64:1559-1576).

Nogo-B receptor deficiency causes cerebral vasculature defects during embryonic development in mice

Nogo-B receptor (NgBR) was identified as a receptor specific for Nogo-B. Our previous work has shown that Nogo-B and its receptor (NgBR) are essential for chemotaxis and morphogenesis of endothelial cells in vitro and intersomitic vessel formation via Akt pathway in zebrafish. Here, we further demonstrated the roles of NgBR in regulating vasculature development in mouse embryo and primitive blood vessel formation in embryoid body culture systems, respectively. Our results showed that NgBR homozygous knockout mice are embryonically lethal at E7.5 or earlier, and Tie2Cre-mediated endothelial cell-specific NgBR knockout (NgBR ecKO) mice die at E11.5 and have severe blood vessel assembly defects in embryo. In addition, mutant embryos exhibit dilation of cerebral blood vessel, resulting in thin-walled endothelial caverns. The similar vascular defects also were detected in Cdh5(PAC)-CreERT2 NgBR inducible ecKO mice. Murine NgBR gene-targeting embryonic stem cells (ESC) were generated by homologous recombination approaches. Homozygous knockout of NgBR in ESC results in cell apoptosis. Heterozygous knockout of NgBR does not affect ESC cell survival, but reduces the formation and branching of primitive blood vessels in embryoid body culture systems. Mechanistically, NgBR knockdown not only decreases both Nogo-B and VEGF-stimulated endothelial cell migration by abolishing Akt phosphorylation, but also decreases the expression of CCM1 and CCM2 proteins. Furthermore, we performed immunofluorescence (IF) staining of NgBR in human cerebral cavernous malformation patient tissue sections. The quantitative analysis results showed that NgBR expression levels in CD31 positive endothelial cells is significantly decreased in patient tissue sections. These results suggest that NgBR may be one of important genes coordinating the cerebral vasculature development.

Sucrose non-fermenting related kinase enzyme is essential for cardiac metabolism

In this study, we have identified a novel member of the AMPK family, namely Sucrose non-fermenting related kinase (Snrk), that is responsible for maintaining cardiac metabolism in mammals. SNRK is expressed in the heart, and brain, and in cell types such as endothelial cells, smooth muscle cells and cardiomyocytes (CMs). Snrk knockout (KO) mice display enlarged hearts, and die at postnatal day 0. Microarray analysis of embryonic day 17.5 Snrk hearts, and blood profile of neonates display defect in lipid metabolic pathways. SNRK knockdown CMs showed altered phospho-acetyl-coA carboxylase and phospho-AMPK levels similar to global and endothelial conditional KO mouse. Finally, adult cardiac conditional KO mouse displays severe cardiac functional defects and lethality. Our results suggest that Snrk is essential for maintaining cardiac metabolic homeostasis, and shows an autonomous role for SNRK during mammalian development.

Derivation and genetic modification of embryonic stem cells from disease-model inbred rat strains

The lack of rat embryonic stem cells (ESCs) and approaches for manipulation of their genomes have restricted the ability to create new genetic models and to explore the function of a single gene in complex diseases in the laboratory rat. The recent breakthrough in isolating germline-competent ESCs from rat and subsequent demonstration of gene knockout has propelled the field forward, but such tools do not yet exist for many disease-model rat strains. Here we derive new ESCs from several commonly used rat models including the Dahl Salt Sensitive (SS), the sequenced Brown Norway (BN), and Fischer (F344) rat and establish the first germline-competent ESCs from a hypertension disease model strain, the Fawn Hooded Hypertensive (FHH) rat. Genetic manipulations including transgenesis mediated by lentivirus, routine homologous recombination, and homologous recombination mediated by zinc-finger nucleases (ZFNs) were performed effectively in FHH rat ESCs. Our results showed these rat ESC lines, isolated from inner cell masses using mechanical splitting, had germline competency; the Pparg gene locus and homologous genomic region to the mouse Rosa26 locus can be targeted effectively in these rat ESCs. Furthermore, our results also demonstrated that ZFNs increased the efficiency of proper homologous recombination in FHH rat ESCs using targeting vectors with short homology arms. These rat ESC lines and advancements in genetic manipulation pave the way to novel genetic approaches in this valuable biomedical model species and for exploration of complex disease in these strains.

Knockout rats via embryo microinjection of zinc-finger nucleases

The toolbox of rat genetics currently lacks the ability to introduce site-directed, heritable mutations into the genome to create knockout animals. By using engineered zinc-finger nucleases (ZFNs) designed to target an integrated reporter and two endogenous rat genes, Immunoglobulin M (IgM) and Rab38, we demonstrate that a single injection of DNA or messenger RNA encoding ZFNs into the one-cell rat embryo leads to a high frequency of animals carrying 25 to 100% disruption at the target locus. These mutations are faithfully and efficiently transmitted through the germline. Our data demonstrate the feasibility of targeted gene disruption in multiple rat strains within 4 months time, paving the way to a humanized monoclonal antibody platform and additional human disease models.