Overexpression of VEGFα as a biomarker of endothelial dysfunction in aortic tissue of α-GAL-Tg/KO mice and its upregulation in the serum of patients with Fabry's disease

Introduction

Fabry's disease is an X-linked lysosomal storage disorder caused by reduced activity of α-galactosidase A (GAL), leading to premature death on account of renal, cardiac, and vascular organ failure. Accumulation of the GAL substrate globotriaosylceramide (Gb3) in endothelial and smooth muscle cells is associated with early vascular cell damage, suggesting endothelial dysfunction as a driver of cardiorenal organ failure. Here, we studied the vascular expression of the key angiogenic factors, VEGFα and its antagonist angiostatin, in Fabry α-GAL-Tg/KO mice and determined circulating VEGFα and angiostatin serum levels in patients with Fabry's disease and healthy controls.

Methods

Cryopreserved aortic vessels from six α-GAL-Tg/KO and six wild-type (WT) mice were obtained and VEGFα and angiostatin levels were determined by performing Western blot analysis. VEGFα expression was visualized by an immunohistochemical staining of paraffin aortic rings. In addition, VEGFα and angiostatin serum levels were measured by using an enzyme-linked immunosorbent assay in 48 patients with genetically verified Fabry's disease (50% male) and 22 healthy controls and correlated with disease severity markers such as lyso-Gb3, albuminuria, NTproBNP, high-sensitive troponin T (hsTNT), and myocardial wall thickness.

Results

It was found that there was a significant increase in VEGFα protein expression (1.66 ± 0.35 vs. 0.62 ± 0.16, p = 0.0009) and a decrease in angiostatin expression (0.024 ± 0.007 vs. 0.053 ± 0.02, p = 0.038) in aortic lysates from α-GAL-Tg/KO compared with that from WT mice. Immunohistochemical staining revealed an adventitial VEGFα signal in α-GAL-Tg/KO mice, whereas no VEGFα signal could be detected in WT mice aortas. No differences in aortic angiostatin expression between α-GAL-Tg/KO- and WT mice could be visualized. The serum levels of VEGFα were significantly upregulated in patients with Fabry's disease compared with that in healthy controls (708.5 ± 426.3 vs. 458.5 ± 181.5 pg/ml, p = 0.048) and positively associated with albuminuria (r = 0.82, p < 0.0001) and elevated NTproBNP (r = 0.87, p < 0.0001) and hsTNT values (r = 0.41, p = 0.048) in male patients with Fabry's disease. For angiostatin, no significant difference was found between patients with Fabry's disease and healthy controls (747.6 ± 390.3 vs. 858.8 ± 599.3 pg/ml).

Discussion

In conclusion, an overexpression of VEGFα and downregulation of its counter player angiostatin in aortic tissue of α-GAL-Tg/KO mice support the hypothesis of an underlying vasculopathy in Fabry's disease. Elevated VEGFα serum levels were also observed in patients with Fabry's disease and were positively associated with elevated markers of organ manifestation in males. These findings suggest that angiogenetic markers, such as VEGFα, may be potentially useful biomarkers for the detection of endothelial dysfunction in classical Fabry's disease.

Mitochondrial and Cellular Function in Fibroblasts, Induced Neurons, and Astrocytes Derived from Case Study Patients: Insights into Major Depression as a Mitochondria-Associated Disease

The link between mitochondria and major depressive disorder (MDD) is increasingly evident, underscored both by mitochondria's involvement in many mechanisms identified in depression and the high prevalence of MDD in individuals with mitochondrial disorders. Mitochondrial functions and energy metabolism are increasingly considered to be involved in MDD's pathogenesis. This study focused on cellular and mitochondrial (dys)function in two atypical cases: an antidepressant non-responding MDD patient ("Non-R") and another with an unexplained mitochondrial disorder ("Mito"). Skin biopsies from these patients and controls were used to generate various cell types, including astrocytes and neurons, and cellular and mitochondrial functions were analyzed. Similarities were observed between the Mito patient and a broader MDD cohort, including decreased respiration and mitochondrial function. Conversely, the Non-R patient exhibited increased respiratory rates, mitochondrial calcium, and resting membrane potential. In conclusion, the Non-R patient's data offered a new perspective on MDD, suggesting a detrimental imbalance in mitochondrial and cellular processes, rather than simply reduced functions. Meanwhile, the Mito patient's data revealed the extensive effects of mitochondrial dysfunctions on cellular functions, potentially highlighting new MDD-associated impairments. Together, these case studies enhance our comprehension of MDD.

Putative nucleotide-based second messengers in archaea

Second messengers transfer signals from changing intra- and extracellular conditions to a cellular response. Over the last few decades, several nucleotide-based second messengers have been identified and characterized in especially bacteria and eukaryotes. Also in archaea, several nucleotide-based second messengers have been identified. This review will summarize our understanding of nucleotide-based second messengers in archaea. For some of the nucleotide-based second messengers, like cyclic di-AMP and cyclic oligoadenylates, their roles in archaea have become clear. Cyclic di-AMP plays a similar role in osmoregulation in euryarchaea as in bacteria, and cyclic oligoadenylates are important in the Type III CRISPR-Cas response to activate CRISPR ancillary proteins involved in antiviral defense. Other putative nucleotide-based second messengers, like 3',5'- and 2',3'-cyclic mononucleotides and adenine dinucleotides, have been identified in archaea, but their synthesis and degradation pathways, as well as their functions as secondary messengers, still remain to be demonstrated. In contrast, 3'-3'-cGAMP has not yet been identified in archaea, but the enzymes required to synthesize 3'-3'-cGAMP have been found in several euryarchaeotes. Finally, the widely distributed bacterial second messengers, cyclic diguanosine monophosphate and guanosine (penta-)/tetraphosphate, do not appear to be present in archaea.

Bariatric surgery in liver cirrhosis

Introduction

Obesity is frequently associated with its hepatic manifestation, the nonalcoholic fatty liver disease (NAFLD). The most effective treatment for morbid obesity is bariatric surgery (BS) also improving NAFLD and liver function. In patients where NAFLD has already progressed to liver cirrhosis, BS can be considered a high-risk procedure. Hence, consideration of the procedure and the most appropriate timing is crucial.

Material and Methods

Obese patients suffering from NAFLD who underwent BS from two German University Medical Centers were retrospectively analyzed.

Results

Twenty-seven patients underwent BS. Most common procedures were laparoscopic Roux-en-Y-gastric (RYGB) and laparoscopic sleeve gastrectomy (SG). All patients suffered from liver cirrhosis Child A. A preoperative transjugular portosystemic shunt (TIPS) was established in three patients and failed in another patient. Postoperative complications consisted of wound healing disorders (n = 2), anastomotic bleeding (n = 1), and leak from the staple line (n = 1). This patient suffered from intraoperatively detected macroscopic liver cirrhosis. Excess weight loss was 73% and 85% after 1 and 2 years, respectively. Two patients suffered from postoperative aggravation of their liver function, resulting in a higher Child-Pugh score, while three could be removed from the waiting list for a liver transplantation.

Conclusion

BS leads to weight loss, both after SG and RYGB, and potential improvement of liver function in liver cirrhosis. These patients need to be considered with care when evaluated for BS. Preoperative TIPS implantation may reduce the perioperative risk in selected patients.

Putative Nucleotide-Based Second Messengers in the Archaeal Model Organisms Haloferax volcanii and Sulfolobus acidocaldarius

Research on nucleotide-based second messengers began in 1956 with the discovery of cyclic adenosine monophosphate (3′,5′-cAMP) by Earl Wilbur Sutherland and his co-workers. Since then, a broad variety of different signaling molecules composed of nucleotides has been discovered. These molecules fulfill crucial tasks in the context of intracellular signal transduction. The vast majority of the currently available knowledge about nucleotide-based second messengers originates from model organisms belonging either to the domain of eukaryotes or to the domain of bacteria, while the archaeal domain is significantly underrepresented in the field of nucleotide-based second messenger research. For several well-stablished eukaryotic and/or bacterial nucleotide-based second messengers, it is currently not clear whether these signaling molecules are present in archaea. In order to shed some light on this issue, this study analyzed cell extracts of two major archaeal model organisms, the euryarchaeon Haloferax volcanii and the crenarchaeon Sulfolobus acidocaldarius, using a modern mass spectrometry method to detect a broad variety of currently known nucleotide-based second messengers. The nucleotides 3′,5′-cAMP, cyclic guanosine monophosphate (3′,5′-cGMP), 5′-phosphoadenylyl-3′,5′-adenosine (5′-pApA), diadenosine tetraphosphate (Ap₄A) as well as the 2′,3′-cyclic isomers of all four RNA building blocks (2′,3′-cNMPs) were present in both species. In addition, H. volcanii cell extracts also contain cyclic cytosine monophosphate (3′,5′-cCMP), cyclic uridine monophosphate (3′,5′-cUMP) and cyclic diadenosine monophosphate (3′,5′-c-di-AMP). The widely distributed bacterial second messengers cyclic diguanosine monophosphate (3′,5′-c-di-GMP) and guanosine (penta-)/tetraphosphate [(p)ppGpp] could not be detected. In summary, this study gives a comprehensive overview on the presence of a large set of currently established or putative nucleotide-based second messengers in an eury- and a crenarchaeal model organism.

EPEN-46. DNA METHYLATION LANDSCAPE OF RECURRENT PEDIATRIC EPENDYMOMA IDENTIFIES KEY DRIVER EVENTS

Pediatric ependymoma has a propensity of developing late and multiple relapses over many years. About 50% of patients will experience relapses and eventually succumb to their disease. Our study is aimed to understand the mechanism of resistance and drivers associated with pediatric ependymoma relapse. We developed 10 sets of patient-derived orthotopic xenograft (PDOX) models of recurrent pediatric ependymoma from both RELA and PFA tumors. Time from primary tumor to last recurrence ranges from 2.75 – 13 years. Number of recurrences per patient ranges from 1 – 7 times. We performed Reduced Representation Bisulfite Sequencing (RRBS) and Whole Genome Bisulfite Sequencing (WGBS) to map the DNA methylation landscape of total of 30 samples of matched primary and recurrent tumors. Molecular subtypes and DNA methylation profiles were maintained, and RELA/PFA signature genes showed similar expression pattern during serial relapses. RELA- and PFA-specific Differentially Methylated CpGs (DMCs) are identified from primary tumors. During the recurrent process, individual patients displayed consistent changes of DMCs and shared DMCs among patients became convergent. We then identified shared common specific DMCs in recurrent RELA and PFA tumors that emerged as the driver signatures. We found that these recurrent DNA methylation signatures could be identified from primary tumors. Our analysis of the PDOX models showed that they can mostly recapitulate humor tumors’ DNA methylation and we were able to identify shared recurrent specific DMCs associated genes in PDOX models. Our comprehensive data is the first of its kind aimed to investigate the epigenetic mechanisms during pediatric ependymoma recurrence.

MBRS-17. EXAMINING THE ROLE OF LHX9 IN GROUP 3 MEDULLOBLASTOMA

Medulloblastoma (MB) is the most common malignant brain tumor of childhood. Despite major advances in our understanding of the biology of MB, novel treatments remain urgently needed. Using a chemical-genomics driven drug repositioning strategy, we identified the cardiac glycoside family of compounds as potential treatments for Group 3 MB. We subsequently demonstrated that single-agent treatment with digoxin prolongs survival in a patient-derived xenograft model (PDOX) of Group 3 MB to a degree comparable to radiation therapy, a mainstay in the treatment of MB. Finally, we examined the mechanism of digoxin-mediated cell killing using RNA-seq. This work identified LHX9, a member of the LIM homeobox family of transcription factors, as the gene most significantly down-regulated following treatment (Huang and Injac et al, Sci Trans Medicine, 2018). Homologs of LHX9 play key roles in cerebellar development via spatially and temporally restricted expression and LHX9 has been proposed as a core transcription factor (TF) in the regulatory circuitry of Group 3 tumors. Loss of function of other core TFs has been shown to impact MB growth. The role of LHX9 in MB, however, has not been previously experimentally evaluated. We now report that knockdown of LHX9 in MB-derived cell lines results in marked growth inhibition raising the possibility that loss of LHX9 plays a major role in digoxin-mediated cell killing and that LHX9 represents a key dependency required for the growth of Group 3 MB. Clinical targeting of core TFs would represent a novel approach to targeting this devastating disease.

[Amendments to the Transplantation Act and impact on the donor situation in Germany]

In Germany, the scarcity of donor organs has persisted over decades and reached an historical low point in the year 2017. A thorough analysis of the causes revealed structural deficits in the identification and registration of possible donors as one of the central reasons for the low donation rate. This prompted the political authorities to act and resulted in two new laws, which led to a modification of the German Transplantation Act. On 1 April 2019, the Act on Improvement of the Cooperation and the Structural Framework for Organ Donation came into force. This Act strengthens the role of the transplant coordinators in the harvesting hospitals and establishes adequate reimbursement of the organ donation-related costs in the harvesting hospitals. Furthermore, it fosters the cooperation of the transplant coordinators with the German organ procurement organization. On 16 January 2020, the existing opt-in legislation was modified. While the general principle of the opt-in legislation stayed unchanged, different measures were introduced that aim to repeatedly inform all citizens about organ donation and thereby motivate them to make a decision on organ donation. In order to enable a reliable and transparent documentation an organ donor registry will be established. The practical implementation of the various measures of both Acts is supported by a multi-institutional collaborative initiative plan for organ donation. The legal regulations and their practical implementation are depicted in detail.

Retour d’expérience des évacuations par train à grande vitesse de patients en syndrome de détresse respiratoire aiguë sur infection à Covid-19 : les missions Chardon

Lors de la crise Covid-19 en France, il a fallu transférer des patients de zones où les lits de réanimation étaient saturés vers d’autres régions. Tous les moyens ont été utilisés : terrestre, aérien, maritime… Pour la première fois, des trains à grande vitesse (TGV) ont été utilisés. Le transport ferroviaire avait été utilisé largement pendant la Première Guerre mondiale. Ces transferts ont nécessité une collaboration extrêmement importante interservices : ministère, agences régionales de santé, hôpitaux, Samu zonaux, Samu, Smur associations de sécurités civiles, sapeurs-pompiers… L’une des collaborations des plus importantes a été celle avec la SNCF qui a permis une adaptation des rames, sécurisations des itinéraires, adaptation de la conduite… Chaque voiture transporte quatre patients intubés en syndrome de détresse respiratoire aiguë avec un médecin senior, un junior, quatre infirmiers et un logisticien pour la réalisation de la surveillance et des soins. Dans chaque rame, une équipe de régulation médicale est présente pour la coordination. Il y a eu dix évacuations sanitaires, qui ont transporté 197 patients sur 6 600 km (350‒950 km/TGV). Le transport le plus long a été de 7 h 14 min. On n’a pas relevé de complications majeures pendant les transferts. Plusieurs questions restent en suspens comme les critères de sélections des patients, la mise en place d’un train sanitaire aménagé permanent, un stock de matériel. Afin de mieux connaître les conséquences sur les patients, une étude est en cours. Les urgentistes ont une nouvelle corde à leur arc avec la possibilité d’effectuer des évacuations sanitaires en TGV pour des patients médicaux graves sur de longues distances.

Covid-19 : les transferts internationaux de patients de réanimation, une solution pour les départements frontaliers

La crise sanitaire de la Covid-19 a imposé une adaptabilité jamais réalisée de notre système de santé. Les services de réanimation et les structures de médecine d’urgence ont dû innover et développer des stratégies novatrices pour garantir des soins de qualité à tous les patients relevant de réanimation. La région Grand-Est, et plus particulièrement les départements de Moselle, du Bas-Rhin et du Haut-Rhin, a été particulièrement touchée. Parmi les 349 patients transférés hors de la région, 164 l’ont été vers des pays européens (Allemagne, Autriche, Luxembourg et Suisse) entre le 14 mars et le 4 avril 2020. Ces transferts internationaux, organisés par l’Agence régionale de santé et les Samu-Centre 15, ont essentiellement fait appel à des moyens aériens des hôpitaux, de l’armée et de la protection civile. L’accompagnement des patients, soigneusement sélectionnés, était assuré par un binôme médecin‒ infirmier spécialisés. Le choix de cette stratégie a permis d’éviter la saturation des services de réanimation et d’avoir à faire un choix entre les patients pouvant ou non bénéficier de soins aigus. L’adaptabilité des professionnels de santé et une organisation au plus près du terrain ont permis de réaliser ces transferts dans de bonnes conditions. Cet épisode témoigne de l’importance de laisser la gestion des crises sanitaires aux professionnels de la santé. Cet article présente l’organisation mise en place en région Grand-Est pour préparer et réaliser ces transferts internationaux.

Abstract C121: Racial/ethnic differences of pediatric brain tumors in the development of orthotopic PDX models

Brain tumor is leading cause of cancer-related death in children. While significant advances have been made in molecularly subgrouping tumors of same pathologic diagnosis, little is known about the biologic differences among racial/ethnic populations, and there is a lack of animal models that represent different racial/ethnic patients. Here, we report our analysis of tumorigenicity of a total of 215 pediatric brain tumors in SCID mice. All surgical tumor tissues were obtained from cryo lab and directly implanted into the anatomically matched locations in mouse brains, i.e., cerebral tumors (such as GBM) into mouse right cerebra, and cerebellar tumors (such as medulloblastoma) into mouse cerebella. The animals were closely monitored following institutional-approved animal protocols. Tumor formation was validated either through the harvesting of visible tumors or via histopathologic examination of paraffin-embedded whole mouse brains. From the 215 tumors, racial/ethnic information was validated in 180 tumors. Overall tumor formation was 41.2% (52/126) in white, 26.9% (7/26) in black, 50% (8/16) in more than one race, and 20% (2/5) in Asian patients. When different tumor types were compared, children with medulloblastoma exhibited similar tumor take rate, ranging from 50% (3/6) in black, to 54% (15/28) in whites and 67% (2/3) of American Indian or Alaska Native, whereas in GBM, it was 79% (11/14) in white, and 1/1 in other racial groups, and in ependymoma, it ranged from 14% (1/7) in American Indian or Alaska to 18% (4/22) in white patients. The tumor take of atypical teratoid/rhabdoid tumor (ATRT) was 63% (5/8) in white but 0% (0/3) in black patient. Low-grade gliomas (total 26) did not form xenografts, and sample size was small (&lt;5) for other types of tumors. Histopathologic and comprehensive molecular characterization of these models confirmed their replication of the original patient tumors. In summary, this study suggested the differences of tumorigenicity among different racial populations and supports the expansion of patient cohorts, particularly the minorities, to draw definitive conclusions. These orthotopic PDX models (7 from African American, 8 from American Indian/Alaska, and 1 each from more than one race and Asian) provided a novel panel of clinically relevant and racial-specific models to facilitate the biologic and preclinical studies on cancer disparities.

Note: This abstract was not presented at the conference.

Citation Format: Lin Qi, Mari Kogiso, Yuchen Du, Yulun Huang, Huiyuan Zhang, Frank Braun, Holly Lindsay, Sibo Zhao, Sarah Injac, Lazlo Perlaky, Patricia Baxter, Wan-Yee Teo, Zhigang Liu, Xiumei Zhao, Yujing Zhang, Jack M.F. Su, Xiao-Nan Li. Racial/ethnic differences of pediatric brain tumors in the development of orthotopic PDX models [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C121.

DDIS-19. USING MATCHED PRIMARY AND RECURRENT PEDIATRIC BRAIN TUMOR ORTHOTOPIC MOUSE MODELS(PDOX) TO ILLUSTRATE THE GENETIC REVOLUTION AND TO INFORM NEW ANTI-RECURRENT PERSONALIZED THERAPIES

BACKGROUND AND PURPOSE

Despite standard treatment largely benefits patients’ survival, tumors may recur as aggressive, therapy resistant relapses. It is imperative to obtain a better understanding of molecular changes that occur after primary tumor resection and treatment. We established a serial of PDOX models using patient tumor tissues procured at different time of patient clinical history.

METHODS

Dissociated tumor cells were cultured in vitro and transplanted into mouse brains. DNA and RNA were then extracted from tumor tissues or cells from patient and established xenografts. Whole genome methylation and transcriptomic profiling as well as histological phenotypes were examined. Standard therapies were conducted in xenografts.

RESULTS

Currently, three sets of matched primary and recurrent tumor xenografts (19850PNET, 100815GGG/GBM and 5958MB) were established. Tumor-take rate increased from 50–70% of primary tumors to 100% of recurrent tumors with decreased tumor onset time (6 months to 3 months), which demonstrated progressive phenotypes. RNA sequencing reveals preserved and newly changed genetic changes in recurrent tumors. High-throughput drug screening discovered a shared and a diverse panel of therapeutic targets that could be selected further for in vivo drug treatment especially for recurrent tumors. Tumor xenografts responded to standard therapy either same or different from clinic outcome, which might indicate the intrinsic or inducible evolutional molecular changes during cancer progression and treatment at different stages.

CONCLUSION

Three sets of matched primary and recurrent pediatric brain tumors, PNET/PNET, GGG/GBM and MB/MB, were successfully established in pediatric orthotopic mice tumor models (PDOXs) providing clinically-relevant and biologically-accurate animal model systems for development of novel therapeutic targets especially for recurrent tumors. Responses of primary and recurrent tumor xenografts to standard chemo-therapy were different possibly due to evolutionarily molecular changes in recurrent tumors during progression or induced by therapies.

EXTH-45. THERAPEUTIC EFFICACY OF MUTANT ISOCITRATE DEHYDROGENASE 1 (IDH1) INHIBITOR SYC-435 WITH STANDARD THERAPY IN PATIENT-DERIVED IDH1 MUTANT GLIOMA XENOGRAFT MOUSE MODELS

Mutation in isocitrate dehydrogenase 1 (IDH1) occurs in >70% of WHO grade II/III astrocytomas, oligodendrogliomas and secondary glioblastoma. The mutant enzyme catalyzes the reduction of α-ketoglutaric acid to D-2-hydroxyglutaric acid, leading to cancer initiation. In this study, we examined therapeutic efficacy of SYC-435 (1-hydroxypyridin-2-one), a newly developed mutant IDH1inhibitor, in IDH1 mutant gliomas. IDH1 R132H mutation (homozygous) was detected in BT142 anaplastic oligoastrocytoma (AOA) and R132C mutation (mutant allele frequency 39–50%) in V0914AOA by pyrosequencing. Suppression of cell growth by SYC-435 was observed with more sensitive of mutant over wild-type IDH1. Patient-derived orthotopic xenograft mouse models of BT142AOA and V0914AOA were treated with vehicle, SYC-435 (15 mg/kg/day x 28 days), temozolomide (50 mg/kg/day x 5 days)/fractionated radiation (2 Gy/day x 5 days) (standard therapy), and SYC-435/standard therapy starting 2 weeks after intracranial tumor implantation. Log rank analysis showed SYC-435 alone did not alter survival times. Although standard therapy significantly prolonged survival times in both models (P< 0.0005), SYC-435/standard therapy further extended survival times (P< 0.05) in V0914AOA and exhibited similar trend in BT142AOA. Elevation of 2-HG/α-KG ratio and methylation of H3K4/H3K9 in V0914AOA tumor compared to wild-type model was detected at the end of treatments. SYC-435 with/without standard therapy tended to reduce 2-HG/α-KG ratio and dramatically reduced methylation of H3K4/H3K9. RNA-seq analysis showed sirtuin signaling pathway, mitochondrial dysfunction and oxidative phosphorylation pathways with mitochondrial DNA (mtDNA) encoded molecules were highly affected by all treatments. However, mtDNA regulation did not correlate to survival benefits. In conclusion, SYC-435 possesses anti-tumor effects that are more sensitive in IDH1 mutant gliomas and generated strong synergistic activities with standard therapies for survival benefits with reduced methylation of H3K4/H3K9. Treatments significantly affected mtDNA but significance to survival benefits remains to be elucidated. Our data support the clinical testing of SYC-435 in patients with IDH1 mutant glioma.

PDTM-17. MiR-126, miR-369-5p AND miR-487b DRIVE PEDIATRIC GLIOBLASTOMA INVASION VIA KCNA1

Diffuse invasion is one of the key features that make GBM particularly difficult to treat. We hypothesize that direct comparison of matched invasive (GBMINV) and tumor core GBM cells (GBMTC) would facilitate the discovery of drivers of pediatric GBM (pGBM) invasion. However, GBMINV cells are extremely difficult to obtain from normal brain tissues because aggressive surgical resection of normal tissue carries the risk of serious neurological deficits. Most past and current studies on GBM invasion were and are forced to utilize the resected primary tumor masses. To overcome this barrier, we utilized a panel of 6 pediatric patient tumor-derived orthotopic xenograft (PDOX) mouse models to isolate matching pairs of GBMTC cells and GBMINV cells and confirmed a significantly elevated invasive capacity in GBMINV cells both in vitro and in vivo. Global profiling of 768 human microRNA using a real-time PCR-based Taqman system identified 23 microRNAs were upregulated in the GBMINV cells in at least 4 of the 6 pGBM models as compared with the matching GBMTC cells. We subsequently showed that silencing the top three miRNAINV, miR-126, miR-369-5p, and miR-487b, suppressed tumor cell migration in vitro (both as neurospheres and monolayer cultures) without affecting cell proliferation, and blocked pGBM invasion in mouse brains. Integrated analysis of the mRNA profiling of the same set of GBMTC and GBMINV cells revealed the affected signaling pathways and identified KCNA1 as the sole common computational target gene of the three miRNAINV. Treatment of three pairs of GBMTC and GBMINV cells with two KCNA1 inhibitors, ADWX1 and Agitoxin 2, caused significant suppression of pGBM cell migration in vitro. In conclusion, this study revealed an intrinsically elevated invasive phenotype in GBMINV cells, identified miR-126, -369-5p, and -487b as novel drivers of pGBM invasion, and characterized KCNA1 as a potential therapeutic target for arresting pGBM invasion.

TMOD-21. TARGETING ANAPLASTIC MENINGIOMA WITH PANOBINOSTAT IN PATIENT-DERIVED ORTHOTOPIC XENOGRAFT (PDOX) MODELS DERIVED FROM A MATCHING PAIR OF PRIMARY AND RECURRENT TUMORS

BACKGROUND

Meningioma is the most common brain tumor in adults. Despite the overall benign nature of meningioma, skull base tumors can be difficult to completely resect while others exhibit progression and aggressive profiles. The lack of clinically relevant animal models is blocking the development of novel therapies.

MATERIAL AND METHODS

Twelve surgical specimens (1 × 105) from 11 adult meningioma patients were implanted into the frontal cranial-base of the brain of SCID mice. Mice were then followed and assessed for tumor formation. Tumor growth was confirmed by small animal MRI. Pathologic features of the PDOX models and the matched patient tumors were compared with standard H&E and immunohistochemical staining. RNAseq was performed to examine the molecular fidelity of PDOX tumors and to identify new therapeutic targets. A panel of 60 clinically-relevant drugs was developed for screening drug sensitivity. In vivo examination of therapeutic efficacy of Panobinostat was performed in two models by treating preformed PDOX tumors with i.p. injection (10 mg/kg), 5 days on, 5 days off for 2 cycles.

RESULTS

Intracranial xenograft formation was confirmed in two samples derived from the same patient, the first an atypical meningioma (K029MEN-P) and the second, which progressed to anaplastic meningioma at recurrence (K029MEN-R). MRI scanning revealed that the PDOX tumors grew from the skull base. These patient tumor cells can be cryopreserved for long-term maintenance of tumorigenicity. The xenograft tumors replicated histopathological features of parental tumors. Overall gene expression profiles of PDOX were similar to the original patient tumors. Using MEN primary culture cells, we screened 60 drugs and identified 12 (20%) active compounds. Panobinostat also significantly prolonged survival of mice bearing orthotopic meningiomas.

CONCLUSION

A set of meningioma PDOX models derived from primary and recurrent tumor was established. Our data further demonstrate that panobinostat exerts potent antitumor activity against high-grade meningioma.

Systems biology-based drug repositioning identifies digoxin as a potential therapy for groups 3 and 4 medulloblastoma

Medulloblastoma (MB) is the most common malignant brain tumor of childhood. Although outcomes have improved in recent decades, new treatments are still needed to improve survival and reduce treatment-related complications. The MB subtypes groups 3 and 4 represent a particular challenge due to their intragroup heterogeneity, which limits the options for "rational" targeted therapies. Here, we report a systems biology approach to drug repositioning that integrates a nonparametric, bootstrapping-based simulated annealing algorithm and a 3D drug functional network to characterize dysregulated driver signaling networks, thereby identifying potential drug candidates. From more than 1300 drug candidates studied, we identified five members of the cardiac glycoside family as potentially inhibiting the growth of groups 3 and 4 MB and subsequently confirmed this in vitro. Systemic in vivo treatment of orthotopic patient-derived xenograft (PDX) models of groups 3 and 4 MB with digoxin, a member of the cardiac glycoside family approved for the treatment of heart failure, prolonged animal survival at plasma concentrations known to be tolerated in humans. These results demonstrate the power of a systematic drug repositioning method in identifying a potential treatment for MB. Our strategy could potentially be used to accelerate the repositioning of treatments for other human cancers that lack clearly defined rational targets.

Cyclic nucleotides in archaea: Cyclic di-AMP in the archaeon Haloferax volcanii and its putative role

The role of cyclic nucleotides as second messengers for intracellular signal transduction has been well described in bacteria. One recently discovered bacterial second messenger is cyclic di‐adenylate monophosphate (c‐di‐AMP), which has been demonstrated to be essential in bacteria. Compared to bacteria, significantly less is known about second messengers in archaea. This study presents the first evidence of in vivo presence of c‐di‐AMP in an archaeon. The model organism Haloferax volcanii was demonstrated to produce c‐di‐AMP. Its genome encodes one diadenylate cyclase (DacZ) which was shown to produce c‐di‐AMP in vitro. Similar to bacteria, the dacZ gene is essential and homologous overexpression of DacZ leads to cell death, suggesting the need for tight regulation of c‐di‐AMP levels. Such tight regulation often indicates the control of important regulatory processes. A central target of c‐di‐AMP signaling in bacteria is cellular osmohomeostasis. The results presented here suggest a comparable function in H. volcanii. A strain with decreased c‐di‐AMP levels exhibited an increased cell area in hypo‐salt medium, implying impaired osmoregulation. In summary, this study expands the field of research on c‐di‐AMP and its physiological function to archaea and indicates that osmoregulation is likely to be a common function of c‐di‐AMP in bacteria and archaea.

Noncontact recognition of fluorescently labeled objects in deep tissue via a novel optical light beam arrangement

To date, few optical imaging systems are available in clinical practice to perform noninvasive measurements transcutaneously. Instead, functional imaging is performed using ionizing radiation or intense magnetic fields in most cases. The applicability of fluorescence imaging (e.g., for the detection of fluorescently labeled objects, such as tumors) is limited due to the restricted tissue penetration of light and the required long exposure time. Thus, the development of highly sensitive and easily manageable instruments is necessary to broaden the utility of optical imaging. To advance these developments, an improved fluorescence imaging system was designed in this study that operates on the principle of noncontact laser-induced fluorescence and enables the detection of fluorescence from deeper tissue layers as well as real-time imaging. The high performance of the developed optical laser scanner results from the combination of specific point illumination, an intensified charge-coupled device (ICCD) detector with a novel light trap, and a filtering strategy. The suitability of the laser scanner was demonstrated in two representative applications and an in vivo evaluation. In addition, a comparison with a planar imaging system was performed. The results show that the exposure time with the developed laser scanner can be reduced to a few milliseconds during measurements with a penetration depth of up to 32 mm. Due to these short exposure times, real-time fluorescence imaging can be easily achieved. The ability to measure fluorescence from deep tissue layers enables clinically relevant applications, such as the detection of fluorescently labeled malignant tumors.

Epidemiological Data on Anaphylaxis in French Emergency Departments

BACKGROUND

Although anaphylaxis has been considered a priority public health issue in the world allergy community, epidemiological data on morbidity and mortality remain suboptimal. We performed the first multicenter epidemiological study in French emergency departments (EDs). The study covered 7 EDs over a period of 1 year. The objectives were to identify areas that are amenable to change and to support ongoing national and international efforts for better diagnosis, management, and prevention of anaphylaxis.

METHODS

Ours was a descriptive study based on data routinely reported to French institutional administrative databases from 7 French public health institutions in the Lorraine region between January and December 2015. Data were collected based on the anaphylaxisrelated codes of the International Classification of Diseases (ICD)-10, and cases were clinically validated as anaphylaxis.

RESULTS

Of the 202 079 admissions to the EDs, 4817 had anaphylaxis-related codes; of these, 323 were clinically validated as anaphylaxis. Although 45.8% were severe, adrenaline was prescribed in only 32.4% of cases. Of the 323 cases, 57.9% were subsequently referred for an allergy work-up or evaluation (after or during hospitalization), and 17.3% were prescribed autoinjectable epinephrine.

CONCLUSION

Our results highlight an urgent need for improved public health initiatives with respect to recognition and treatment of anaphylaxis. We flag key problems that should be managed in the coming years through implementation of national and international actions.

Sex-specific and lasting effects of a single course of antenatal betamethasone treatment on human placental 11β-HSD2

INTRODUCTION

We have previously shown that even a single course of antenatal betamethasone (BET) as an inductor for lung maturity reduces birth weight and head circumference. Moreover, animal studies link BET administration to alterations of the hypothalamic-pituitary-adrenal-gland-axis (HPA). The unhindered development of the fetal HPA axis is dependent on the function and activity of 11β-hydroxysteroiddehydrogenase type 2 (11β-HSD2), a transplacental cortisol barrier. Therefore, we investigated the effects of BET on this transplacental barrier and fetal growth.

METHODS

Pregnant women treated with a single course of BET between 23 + 5 to 34 + 0 weeks of gestation were compared to gestational-age-matched controls. Placental size and neonatal anthropometrics were taken. Cortisol and ACTH levels were measured in maternal and umbilical cord blood samples. Placental 11β-hydroxysteroiddehydrogenase type 1 (11β-HSD1) protein levels and 11β-HSD2 protein and activity levels were determined. Parameters were analyzed independent of sex, and in subgroups divided by gender and gestational age.

RESULTS

In term born females, BET administration was associated with reduced head circumference and decreased 11β-HSD2 protein levels and enzyme activity. Males treated with BET, especially those born prematurely, showed increased 11β-HSD2 protein levels.

CONCLUSION

A single course of BET alters placental glucocorticoid metabolism in a sex-specific manner. Decreased 11β-HSD2 levels in term born females may lead to an increased placental transfer of maternal cortisol and therefore result in a reduced head circumference and a higher risk for altered stress response in adulthood. Further research is needed to conclude the significance of increased 11β-HSD2 levels in males.

Abstract LB-069: Identification of personalized active agents in pediatric medulloblastoma through high-throughput drug screening in matching pairs of patient derived orthotopic xenograft neurosphere and monolayer cells

Objective: Glioblastoma and Medulloblastoma are deadliest brain tumors both in adults and children. While next-generation sequencing rapidly identifies whole exome/genome gene mutations, the efficacy of targeting mutated genes/pathways has not been systematically analyzed. Additionally, it remains unknown if neurospheres (enriched with cancer stem cells) and non-stem monolayer tumor cells will respond equally to the same target therapies.

Methods: Matching pairs of neurosphere and monolayer cell cultures from 4 molecularly characterized PDOX mouse models established from distinct clinical stages of pediatric GBM and MB were treated with 7,913 drugs (mostly in clinical use or trials) at 4 doses (0-10 uM) for 3 and 7 days. Dose-response curves and active area under the curve were constructed to identify active drugs and correlate with model-specific gene mutations.

Results: Relatively long-term treatment (7 day screening) was achieved for high-throughput drug screening and revealed time- and dose-dependent effects in most of the 4,629 compounds that were active in at least one culture at one time point. When gene mutations were druggable, not all inhibitors of the same family were active. In IC-4687GBM (a treatment-naïve GBM), high NF1 mutation (&gt;76-99% allele) frequency was found in patient tumor, xenografts, and cultured cells, but only 3/17 MEK inhibitors were active in neurospheres and 2/17 in monolayer cells (GDC0980 and PI-103 were active in both) on day 7. In IC-R0315GBM (from an autopsied terminal GBM) that carried PI3KCA mutation (allele frequency 22-27%), 5/33 PI3K inhibitors were active in neurospheres and 8/33 in monolayer cells (only Tremetinib was active in both) after 7 days. In IC-3752GBM (recurrent GBM) and ICb-1127AA (radiation-induced anaplastic astrocytoma), no druggable mutations were detected. The number of active drugs on day 7 was 366 in IC-4768GBM, 406 in IC-3752GBM, 284 in IC-R0315GBM, and 305 in ICb-1277AA. When the 4 matching pairs of neurospheres and monolayers were compared, the agents active in both cultures ranged from 36% to 60%, active only in neurosphere from 10.3% to 25%, and active only in monolayer cells from 14.8% to 53%. The response of MB to the drugs is on the way for analysis.

Conclusion: We showed that long-term treatment is feasible for high-throughput drug screening. Targeting druggable mutations can be achieved but only by a fraction of specific agents. Neurospheres and monolayer cells do not always respond equally toward the same drugs, and effective targeting of both subpopulations is needed to generate prolonged animal survival times.

Citation Format: Lin Qi, Yuchen Du, Goeun Bae, Mari Mari, Frank Braun, Holly Lindsay, Huiyuan Zhang, Sibo Zhao, Sarah Injac, Patricia Baxter, Jack Su, Michael Mancini, Oliver Hampton, William Parsons, Mural Chintagumpala, Clifford Stephan, Peter Davies, Xiaonan Li. Identification of personalized active agents in pediatric medulloblastoma through high-throughput drug screening in matching pairs of patient derived orthotopic xenograft neurosphere and monolayer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-069.

Towards an unsupervised device for the diagnosis of childhood pneumonia in low resource settings: automatic segmentation of respiratory sounds

Pneumonia remains the worldwide leading cause of children mortality under the age of five, with every year 1.4 million deaths. Unfortunately, in low resource settings, very limited diagnostic support aids are provided to point-of-care practitioners. Current UNICEF/WHO case management algorithm relies on the use of a chronometer to manually count breath rates on pediatric patients: there is thus a major need for more sophisticated tools to diagnose pneumonia that increase sensitivity and specificity of breath-rate-based algorithms. These tools should be low cost, and adapted to practitioners with limited training. In this work, a novel concept of unsupervised tool for the diagnosis of childhood pneumonia is presented. The concept relies on the automated analysis of respiratory sounds as recorded by a point-of-care electronic stethoscope. By identifying the presence of auscultation sounds at different chest locations, this diagnostic tool is intended to estimate a pneumonia likelihood score. After presenting the overall architecture of an algorithm to estimate pneumonia scores, the importance of a robust unsupervised method to identify inspiratory and expiratory phases of a respiratory cycle is highlighted. Based on data from an on-going study involving pediatric pneumonia patients, a first algorithm to segment respiratory sounds is suggested. The unsupervised algorithm relies on a Mel-frequency filter bank, a two-step Gaussian Mixture Model (GMM) description of data, and a final Hidden Markov Model (HMM) interpretation of inspiratory-expiratory sequences. Finally, illustrative results on first recruited patients are provided. The presented algorithm opens the doors to a new family of unsupervised respiratory sound analyzers that could improve future versions of case management algorithms for the diagnosis of pneumonia in low-resources settings.

Abstract 4214: Identification of personalized active agents in pediatric gliomas through high-throughput drug screening in matching pairs of patient derived orthotopic xenograft (PDOX) neurosphere and monolayer cells

Objective: Glioblastoma (GBM) is one of the deadliest brain tumors both in adults and children. While next-generation sequencing rapidly identifies whole exome/genome gene mutations, the efficacy of targeting mutated genes/pathways has not been systematically analyzed. Additionally, it remains unknown if neurospheres (enriched with cancer stem cells) and non-stem monolayer tumor cells will respond equally to the same target therapies.

Methods: Matching pairs of neurosphere and monolayer cell cultures from 4 molecularly characterized PDOX mouse models established from distinct clinical stages of pediatric glioma (treatment-naïve, early recurrent, terminal, and radiation-induced) were treated with 7,913 drugs (mostly in clinical use or trials) at 4 doses (0-10 uM) for 3 and 7 days. Dose-response curves and active area under the curve (AAUC) were constructed to identify active drugs and correlate with model-specific gene mutations.

Results: Relatively long-term treatment (7 day screening) was achieved for high-throughput drug screening and revealed time- and dose-dependent effects in most of the 4,629 compounds that were active in at least one culture at one time point. When gene mutations were druggable, not all inhibitors of the same family were active. In IC-4687GBM (a treatment-naïve GBM), high NF1 mutation (&gt;76-99% allele) frequency was found in patient tumor, xenografts, and cultured cells, but only 3/17 MEK inhibitors were active in neurospheres and 2/17 in monolayer cells (GDC0980 and PI-103 were active in both) on day 7. In IC-R0315GBM (from an autopsied terminal GBM) that carried PI3KCA mutation (allele frequency 22-27%), 5/33 PI3K inhibitors were active in neurospheres and 8/33 in monolayer cells (only Tremetinib was active in both) after 7 days. In IC-3752GBM (recurrent GBM) and ICb-1127AA (radiation-induced anaplastic astrocytoma), no druggable mutations were detected. The number of active drugs on day 7 was 366 in IC-4768GBM, 406 in IC-3752GBM, 284 in IC-R0315GBM, and 305 in ICb-1277AA. When the 4 matching pairs of neurospheres and monolayers were compared, the agents active in both cultures ranged from 36% to 60%, active only in neurosphere from 10.3% to 25%, and active only in monolayer cells from 14.8% to 53%. Subsequent in vivo validation using MLN8327 in IC-4687GBM and IC-R0315GBM showed that effective targeting of both neurosphere and monolayer was required for significantly-improved animal survival times.

Conclusion: We showed that long-term treatment is feasible for high-throughput drug screening. Targeting druggable mutations can be achieved but only by a fraction of specific agents. Neurospheres and monolayer cells do not always respond equally toward the same drugs, and effective targeting of both subpopulations is needed to generate prolonged animal survival times.

Citation Format: Lin Qi, Yuchen Du, Mari Kogiso, Goeun Bae, Frank Braun, Holly Lindsay, Huiyuan Zhang, Sibo Zhao, Sarah Injac, Patricia Baxter, Jack Su, Michael Mancini, Oliver Hampton, William Parsons, Murali Chintagumpala, Clifford Stephan, Peter Davies, Xiao-Nan Li, Xiao-Nan Li. Identification of personalized active agents in pediatric gliomas through high-throughput drug screening in matching pairs of patient derived orthotopic xenograft (PDOX) neurosphere and monolayer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4214. doi:10.1158/1538-7445.AM2017-4214

Abstract 5058: Lysine specific demethylase-1 (LSD-1) Inhibitor SYC-836 in combination with radiation prolongs animal survival in patient-derived posterior fossa ependymoma xenograft mouse models

Background: Ependymoma (EPN) is the third most common malignant pediatric brain tumor. Current standard therapy include maximally safe surgical resection followed by radiation and lead to a 5-year overall survival of 50-71%. Recent molecular subgrouping of EPN has identified one group, posterior fossa A (PFA), which accounts for 45% of all EPN cases, to have one of the worst prognosis and it is driven by epigenetic changes, suggesting targeting epigenetic changes in PFA EPN can potentially be effective. In this study, we examined the therapeutic efficacy of SYC-836, a novel LSD-1 inhibitor compound developed at Baylor College of Medicine, both in vitro and in vivo in PDOX models of posterior fossa EPN.

Methods: To examine in vitro anti-tumor activities, paired primary cultured cells (both as attached cells and neurospheres) from an established PDOX model of posterior fossa EPN (ICb-4423EPN) were subjected to SYC-836 at various concentrations (0-25uM). Cell viability and proliferation were measured using Cell Counting Kit-8 assay at 5 different time points over 14 days. To validate the drug’s in vivo efficacy, two established posterior fossa EPN PDOX models, ICb-4423EPN and ICb-2002EPN, were utilized. 40 eight weeks old SCID mice per model were implanted with tumor cells. They were divided into 4 treatment groups (10 mice/group) each: 1) control (DPBS, 10uL/kg IP daily x 28 days), 2) radiation/standard therapy (2 Gy focal XRT daily x 5 days), 3) SYC-836 only (15mg/kg IP daily x 28 days), and 4) combination (radiation + SYC-836 per regimen above). Animal survival times were analyzed using log rank analysis. Changes of histone lysine methylation were examined through western hybridization.

Results: SYC-836 demonstrated effective cell killing in vitro against both attached and neurosphere cultured cells in both time- and dose-dependent manner. IC50 was ~7.5uM. In vivo experiment was completed in 1 of the 2 EPN PDOX models (ICb-2002EPN) with the second model ongoing. Median survival times for each group is as followed: control 136 days, radiation 148 days, SYC-836 only 136 days, combination 180 days. There were no survival benefit with either XRT only (P=0.205) or SYC-836 only (P=0.186) when compared to the control group; however, when used in combination, the treatment strategy lead to significant improvement in animal survival (P=0.004). SYC-836 was well tolerated in mice.

Conclusion: Our data showed that combining SYC-836 with current standard therapy of radiation synergistically prolongs animal survival significantly, although as a single agent SYC-836 was not effective against posterior fossa ependymoma. Our data suggest that SYC-836 may have a role in the clinical setting by either reducing radiation dosages, or be a potential adjuvant agent to other chemotherapy drugs in our treatment approach for ependymoma.

Citation Format: Sibo Zhao, Huiyuan Zhang, Lin Qi, Holly Lindsay, Yuchen Du, Mari Kogiso, Frank Braun, Sarah Injac, Laszlo Perlaky, Donald W. Parsons, Murali Chintagumpala, Adekunle Adesina, Yongcheng Song, Xiao-Nan Li. Lysine specific demethylase-1 (LSD-1) Inhibitor SYC-836 in combination with radiation prolongs animal survival in patient-derived posterior fossa ependymoma xenograft mouse models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5058. doi:10.1158/1538-7445.AM2017-5058

Abstract 2821: Impact of SCID mouse gender on tumorigenicity, xenograft growth and drug-responses in patient derived orthotopic xenograft models (PDOX) of malignant brain tumors

Brain tumor is the leading cause of cancer related death in children. To develop new therapies and to understand tumor biology, many efforts are made to develop patient derived orthotopic xenograft mouse models (PDOX). There are, however, some concerns about the potential impact of animal genders on tumor take rate, xenograft growth and in vivo drug responses. To systematically analyze such impact, we retrospectively examined &gt;1,000 mice of 59 PDOX models, including glioblastoma (GBM), medulloblastoma (MB), primitive neuroectodermal tumor (PENT) and ependymoma (EPN) and diffuse intrinsic pontine glioma (DIPG), in which there were age-matched (within 2 wks differences) with relatively even numbers of male and female animals. All the animals were injected with identical number of tumor cells (1x10^5) in the mouse brains matching that in human patients. Animals were monitored daily and euthanized when they were moribund. Differences between male and female mice were analyzed by t-test. In 25 GBM models (15 adult and 10 pediatric) involving 419 mice, there was an average of number of mice was 17.8±9.5 mice per model (male: female = 9.88±5.8:7.93±3.6) (P&gt;0.05). In 26 MB models with total 488 mice, the average animal number was 17.24±8.8 mice per model (male:female= 9.54±5.34 :7.71±3.45) (P&gt;0.05). The tumor take rate was near &gt;95% in both male and female mice (P&gt;0.05). In GBM models, the survival times was 94.1±21.7 days in male mice and 92.3±20.8 days in female (P&gt;0.05); wherease in MB models, they were 134.95±39.86 day in male and 121.08±31.68 days in female mice (P&gt;0.05). The impact of animal gender on drug responses in vivo is essential to the preclinical drug testing. A total of 468 mice from 11 GBM, 5 MB, 3 EPN, 3 DIPG and 2 PNET were treated a series of standard and investigational drugs/compounds, including radiation, oncolytic virus (SVV-001), ABT888, BMI1-inhibitor, MLN8237, TMZ, Flavopiridol, SYC-435, SYC-719, SYC-836, Olig 2 inhibitor, VPA, SAHA, Echinomycin, MCB613, and PARPi. The overall survival times were 104.55±23.63 day in male mice, and 98.64±25.66 in female mice (P&gt;0.05). The only model that exhibited the increased responses in male mice was found in IC-2305GBM treated with TMZ and PTC-596 (P&lt;0.05). In conclusion, our data demonstrated that the gender of SCID mice does not have major impact on animal development nor in drug responses, and SCID mice of both genders are appropriate for brain tumor PDOX model development.

Citation Format: Lin Qi, Mari Kogiso, Yuchen Du, Huiyuan Zhang, Frank Braun, Holly Lindsay, Sibo Zhao, Sarah Injac, Patricia Baxter, Zhigang Liu, Yujing Zhang, Jack Su, Adekunle Adesina, Andrew Walter, Jeffery Murray, Javad Nazarian, Will Parsons, Murali Chintagumpala, Xiao-nan Li. Impact of SCID mouse gender on tumorigenicity, xenograft growth and drug-responses in patient derived orthotopic xenograft models (PDOX) of malignant brain tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2821. doi:10.1158/1538-7445.AM2017-2821