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This table provide supplemental information on the results of ChIP-seq and gene expression analyses of primary and spinal metastatic tumors in MAP mice.

This file provides illustration of supplemental experimental results and explanation of data presented. Supplemental Figure 1 Analysis of gene expression in CAG-A1Z transgenic mice. Supplemental Figure 2 Normal cerebellar development in Atoh1 transgenic animals. Supplemental Figure 3 Atoh1 over-expression enhances MB development and metastasis along the spinal cord in Ptch1+/- mice. Supplemental Figure 4 ATOH1-driven MB development and metastasis. Supplemental Figure 5 Analysis of gene expression in SHH MB from different mouse strains. Supplemental Figure 6 ATOH1-driven development and metastasis in AAP and LAP mice. Supplemental Figure 7 Analysis of gene expression in human MB. Supplemental Figure 8 Analysis of gene expression in MB from MAP animals.

This section provides detailed information on experimental procedures and data analysis methods.

Medulloblastoma arising from the cerebellum is the most common pediatric brain malignancy, with leptomeningeal metastases often present at diagnosis and recurrence associated with poor clinical outcome. In this study, we used mouse medulloblastoma models to explore the relationship of tumor pathophysiology and dysregulated expression of the NOTCH pathway transcription factor ATOH1, which is present in aggressive medulloblastoma subtypes driven by aberrant Sonic Hedgehog/Patched (SHH/PTCH) signaling. In experiments with conditional ATOH1 mouse mutants crossed to Ptch1+/− mice, which develop SHH-driven medulloblastoma, animals with Atoh1 transgene expression developed highly penetrant medulloblastoma at a young age with extensive leptomeningeal disease and metastasis to the spinal cord and brain, resembling xenografts of human SHH medulloblastoma. Metastatic tumors retained abnormal SHH signaling like tumor xenografts. Conversely, ATOH1 expression was detected consistently in recurrent and metastatic SHH medulloblastoma. Chromatin immunoprecipitation sequencing and gene expression profiling identified candidate ATOH1 targets in tumor cells involved in development and tumorigenesis. Among these targets specific to metastatic tumors, there was an enrichment in those implicated in extracellular matrix remodeling activity, cytoskeletal network and interaction with microenvironment, indicating a shift in transcriptomic and epigenomic landscapes during metastasis. Treatment with bone morphogenetic protein or SHH pathway inhibitors decreased tumor cell proliferation and suppressed metastatic tumor growth, respectively. Our work reveals a dynamic ATOH1-driven molecular cascade underlying medulloblastoma metastasis that offers possible therapeutic opportunities. Cancer Res; 77(14); 3766–77. ©2017 AACR.

This table provides sequence information for primers and probes used in RT-qPCR.

Supplementary Materials and Methods from Inhibition of RAS-Mediated Transformation and Tumorigenesis by Targeting the Downstream E3 Ubiquitin Ligase Seven in Absentia Homologue

Supplementary Figure 1 from Inhibition of RAS-Mediated Transformation and Tumorigenesis by Targeting the Downstream E3 Ubiquitin Ligase Seven in Absentia Homologue

Supplementary Figure 3 from Inhibition of RAS-Mediated Transformation and Tumorigenesis by Targeting the Downstream E3 Ubiquitin Ligase Seven in Absentia Homologue

Supplementary Table 1 from Inhibition of RAS-Mediated Transformation and Tumorigenesis by Targeting the Downstream E3 Ubiquitin Ligase Seven in Absentia Homologue

Supplementary Figure 4 from Inhibition of RAS-Mediated Transformation and Tumorigenesis by Targeting the Downstream E3 Ubiquitin Ligase Seven in Absentia Homologue

Supplementary Figure 5 from Inhibition of RAS-Mediated Transformation and Tumorigenesis by Targeting the Downstream E3 Ubiquitin Ligase Seven in Absentia Homologue

Supplementary Figure 2 from Inhibition of RAS-Mediated Transformation and Tumorigenesis by Targeting the Downstream E3 Ubiquitin Ligase Seven in Absentia Homologue

Constitutively active RAS small GTPases promote the genesis of human cancers. An important goal in cancer biology is to identify means of countervailing activated RAS signaling to reverse malignant transformation. Oncogenic K-RAS mutations are found in virtually all pancreatic adenocarcinomas, making the RAS pathway an ideal target for therapeutic intervention. How to best contravene hyperactivated RAS signaling has remained elusive in human pancreatic cancers. Guided by the Drosophila studies, we reasoned that a downstream mediator of RAS signals might be a suitable anti-RAS target. The E3 ubiquitin ligase seven in absentia (SINA) is an essential downstream component of the Drosophila RAS signal transduction pathway. Thus, we determined the roles of the conserved human homologues of SINA, SIAHs, in mammalian RAS signaling and RAS-mediated tumorigenesis. We report that similar to its Drosophila counterpart, human SIAH is also required for oncogenic RAS signaling in pancreatic cancer. Inhibiting SIAH-dependent proteolysis blocked RAS-mediated focus formation in fibroblasts and abolished the tumor growth of human pancreatic cancer cells in soft agar as well as in athymic nude mice. Given the high level of conservation of RAS and SIAH function, our study provides useful insights into altered proteolysis in the RAS pathway in tumor initiation, progression, and oncogenesis. By targeting SIAH, we have found a novel means to contravene oncogenic RAS signaling and block RAS-mediated transformation/tumorigenesis. Thus, SIAH may offer a novel therapeutic target to halt tumor growth and ameliorate RAS-mediated pancreatic cancer. [Cancer Res 2007;67(24):11798–810]

Genomic medicine holds great promise for improving health care, but integrating searchable and actionable genetic data into electronic health records (EHRs) remains a challenge. Here we describe Neptune, a system for managing the interaction between a clinical laboratory and an EHR system during the clinical reporting process. We developed Neptune and applied it to two clinical sequencing projects that required report customization, variant reanalysis, and EHR integration. Neptune has been applied for the generation and delivery of over 15,000 clinical genomic reports. This work spans two clinical tests based on targeted gene panels that contain 68 and 153 genes respectively. These projects demanded customizable clinical reports that contained a variety of genetic data types including single-nucleotide variants (SNVs), copy-number variants (CNVs), pharmacogenomics, and polygenic risk scores. Two variant reanalysis activities were also supported, highlighting this important workflow. Methods are needed for delivering structured genetic data to EHRs. This need extends beyond developing data formats to providing infrastructure that manages the reporting process itself. Neptune was successfully applied on two high-throughput clinical sequencing projects to build and deliver clinical reports to EHR systems. The software is open source and available at https://gitlab.com/bcm-hgsc/neptune .

Familial Hypercholesterolemia (FH) is underdiagnosed in the United States. Clinical decision support (CDS) could increase FH detection once implemented in clinical workflows. We deployed CDS for FH at an academic medical center and sought clinician insights using an implementation survey. In November 2020, the FH CDS was deployed in the electronic health record at all Mayo Clinic sites in two formats: a best practice advisory (BPA) and an in-basket alert. Over three months, 104 clinicians participated in the survey (response rate 11.1%). Most clinicians (81%) agreed that CDS implementation was a good option for identifying FH patients; 78% recognized the importance of implementing the tool in practice, and 72% agreed it would improve early diagnosis of FH. In comparing the two alert formats, clinicians found the in-basket alert more acceptable (p = 0.036) and more feasible (p = 0.042) than the BPA. Overall, clinicians favored implementing the FH CDS in clinical practice and provided feedback that led to iterative refinement of the tool. Such a tool can potentially increase FH detection and optimize patient management.

Objective Familial hypercholesterolemia (FH), a prevalent genomic disorder that increases risk of coronary heart disease, remains significantly underdiagnosed. Clinical decision support (CDS) tools have the potential to increase FH detection. We describe our experience in the development and implementation of a genomic CDS for FH at a large academic medical center.Methods CDS development and implementation were conducted in four phases: (1) development and validation of an algorithm to identify “possible FH”; (2) obtaining approvals from institutional committees to develop the CDS; (3) development of the initial prototype; and (4) use of an implementation science framework to evaluate the CDS.Results The timeline for this work was approximately 4 years; algorithm development and validation occurred from August 2018 to February 2020. During this 4-year period, we engaged with 15 stakeholder groups to build and integrate the CDS, including health care providers who gave feedback at each stage of development. During CDS implementation six main challenges were identified: (1) need for multiple institutional committee approvals; (2) need to align the CDS with institutional knowledge resources; (3) need to adapt the CDS to differing workflows; (4) lack of institutional guidelines for CDS implementation; (5) transition to a new institutional electronic health record (EHR) system; and (6) limitations of the EHR related to genomic medicine.Conclusion We identified multiple challenges in different domains while developing CDS for FH and integrating it with the EHR. The lessons learned herein may be helpful in streamlining the development and deployment of CDS to facilitate genomic medicine implementation.

Background Brain tumors are the leading cause of cancer death for pediatric patients. Pelareorep, an immunomodulatory oncolytic reovirus, has intravenous efficacy in preclinical glioma models when preconditioned with GM-CSF (sargramostim). We report a phase I trial with the primary goal of evaluating the safety of sargramostim/pelareorep in pediatric patients with recurrent or refractory high-grade brain tumors and a secondary goal of characterizing immunologic responses. Methods The trial was open to pediatric patients with recurrent or refractory high-grade brain tumors (3 + 3 cohort design). Each cycle included 3 days of subcutaneous sargramostim followed by 2 days of intravenous pelareorep. Laboratory studies and imaging were acquired upon recruitment and periodically thereafter. Results Six patients participated, including three glioblastoma, two diffuse intrinsic pontine glioma, and one medulloblastoma. Two pelareorep dose levels of 3 × 108 and 5 × 108 tissue culture infectious dose 50 (TCID50) were assessed. One patient experienced a dose limiting toxicity of persistent hyponatremia. Common low-grade (1 or 2) adverse events included transient fatigue, hypocalcemia, fever, flu-like symptoms, thrombocytopenia, and leukopenia. High-grade (3 or 4) adverse events included neutropenia, lymphopenia, leukopenia, hypophosphatemia, depressed level of consciousness, and confusion. All patients progressed on therapy after a median of 32.5 days and died a median of 108 days after recruitment. Imaging at progression did not show evidence of pseudoprogression or inflammation. Correlative assays revealed transient but consistent changes in immune cells across patients. Conclusions Sargramostim/pelareorep was administered to pediatric patients with recurrent or refractory high-grade brain tumors. Hyponatremia was the only dose limiting toxicity (DLT), though maximum tolerated dose (MTD) was not determined.

The advancement of precision medicine requires new methods to coordinate and deliver genetic data from heterogeneous sources to physicians and patients. The eMERGE III Network enrolled >25,000 participants from biobank and prospective cohorts of predominantly healthy individuals for clinical genetic testing to determine clinically actionable findings. The network developed protocols linking together the 11 participant collection sites and 2 clinical genetic testing laboratories. DNA capture panels targeting 109 genes were used for testing of DNA and sample collection, data generation, interpretation, reporting, delivery, and storage were each harmonized. A compliant and secure network enabled ongoing review and reconciliation of clinical interpretations, while maintaining communication and data sharing between clinicians and investigators. A total of 202 individuals had positive diagnostic findings relevant to the indication for testing and 1,294 had additional/secondary findings of medical significance deemed to be returnable, establishing data return rates for other testing endeavors. This study accomplished integration of structured genomic results into multiple electronic health record (EHR) systems, setting the stage for clinical decision support to enable genomic medicine. Further, the established processes enable different sequencing sites to harmonize technical and interpretive aspects of sequencing tests, a critical achievement toward global standardization of genomic testing. The eMERGE protocols and tools are available for widespread dissemination.

Electronic health record (EHR)-based clinical decision support (CDS) can address the low awareness and undertreatment of familial hypercholesterolemia (FH), a disorder associated with a markedly increased risk of coronary heart disease. We aimed to incorporate provider perspectives into the development and implementation of a CDS tool for FH. An implementation science framework and a user-centered design process were used to create a CDS tool for FH. Primary care physicians and specialist physicians participated in qualitative interviews, usability testing and an implementation survey. The CDS was configured in two formats—a best practice alert (BPA) and an in-basket message and subsequently deployed in the EHR in silent mode. The key themes that emerged from the analysis of interview transcripts included understanding and awareness of FH, clinical workflow, physician preferences and value of CDS tools, perspectives on patient needs and values and dissemination and implementation. Recommendations related to usability included preferred CDS format and placement, content, timing and frequency, and level of alert urgency/prioritization. In response to the survey, 84.6% of physicians agreed that the CDS would improve early FH diagnosis and 92.3% agreed that it would help them identify and manage FH patients. Physician feedback led to iterative CDS refinement. In summary, we developed a CDS tool for FH using an implementation science framework and physician feedback. Initial deployment revealed a significant burden of FH and the potential for the CDS tool to have a large impact.

Restoration of kidney tubular epithelium following sublethal injury sequentially involves partial epithelial–mesenchymal transition (pEMT), proliferation, and further redifferentiation into specialized tubule epithelial cells (TECs). Because the immunosuppressant cyclosporine-A produces pEMT in TECs and inhibits the peptidyl-prolyl isomerase (PPIase) activity of cyclophilin (Cyp) proteins, we hypothesized that cyclophilins could regulate TEC phenotype. Here we demonstrate that in cultured TECs, CypA silencing triggers loss of epithelial features and enhances transforming growth factor β (TGFβ)-induced EMT in association with upregulation of epithelial repressors Slug and Snail. This pro-epithelial action of CypA relies on its PPIase activity. By contrast, CypB emerges as an epithelial repressor, because CypB silencing promotes epithelial differentiation, prevents TGFβ-induced EMT, and induces tubular structures in 3D cultures. In addition, in the kidneys of CypB knockout mice subjected to unilateral ureteral obstruction, inflammatory and pro-fibrotic events were attenuated. CypB silencing/knockout leads to Slug, but not Snail, downregulation. CypB support of Slug expression depends on its endoplasmic reticulum location, where it interacts with calreticulin, a calcium-buffering chaperone related to Slug expression. As CypB silencing reduces ionomycin-induced calcium release and Slug upregulation, we suggest that Slug expression may rely on CypB modulation of calreticulin-dependent calcium signaling. In conclusion, this work uncovers new roles for CypA and CypB in modulating TEC plasticity and identifies CypB as a druggable target potentially relevant in promoting kidney repair., Graphical abstract

Background Familial hypercholesterolemia, a prevalent genetic disorder, remains significantly underdiagnosed in the United States. Cascade testing, wherein individuals diagnosed with familial hypercholesterolemia— probands—contact their family members to inform them of their risk for familial hypercholesterolemia, has low uptake in the United States. Digital tools are needed to facilitate communication between familial hypercholesterolemia probands and their family members and to promote sharing of familial hypercholesterolemia–related risk information. Objective We aimed to create and evaluate a web-based tool designed to enhance familial communication and promote cascade testing for familial hypercholesterolemia. Methods A hybrid type 1 implementation science framework and a user-centered design process were used to develop an interactive web-based tool—FH Family Share—that enables familial hypercholesterolemia probands to communicate information about their familial hypercholesterolemia diagnosis with at-risk relatives. Probands can also use the tool to draw a family pedigree and learn more about familial hypercholesterolemia through education modules and curated knowledge resources. Usability guidelines and standards were taken into account during the design and development of the tool. The initial prototype underwent a cognitive walkthrough, which was followed by usability testing with key stakeholders including genetic counselors and patients with familial hypercholesterolemia. Participants navigated the prototype using the think-aloud technique, and their feedback was used to refine features of the tool. Results Key themes that emerged from the cognitive walkthrough were design, format, navigation, terminology, instructions, and learnability. Expert feedback from the cognitive walkthrough resulted in a rebuild of the web-based tool to align it with institutional standards. Usability testing with genetic counselors and patients with familial hypercholesterolemia provided insights on user experience, satisfaction and interface design and highlighted specific modifications that were made to refine the features of FH Family Share. Genetic counselors and patients with familial hypercholesterolemia suggested inclusion of the following features in the web-based tool: (1) a letter-to-family-member email template, (2) education modules, and (3) knowledge resources. Surveys revealed that 6 of 9 (67%) genetic counselors found information within FH Family Share very easy to find, and 5 of 9 (56%) genetic counselors found information very easy to understand; 5 of 9 (56%) patients found information very easy to find within the website, and 7 of 9 (78%) patients found information very easy to understand. All genetic counselors and patients indicated that FH Family Share was a resource worth returning to. Conclusions FH Family Share facilitates communication between probands and their relatives. Once informed, at-risk family members have the option to seek testing and treatment for familial hypercholesterolemia.

T cell acute lymphoblastic leukemia (T-ALL) is a serious hematologic malignancy that occurs in children and young adults. Current therapies include intensive chemotherapy and ionizing radiation that preferentially kill malignant cells. Unfortunately, they are frequently accompanied by unintended negative impacts, including the induction of cellular senescence and long-term toxicities in normal host tissues. Whether these senescent cells resulting from therapy increase the susceptibility to relapse or secondary cancers is unknown. Using transgenic and pharmacological approaches to eliminate doxorubicin-induced senescent cells in a Notch-driven T-ALL relapse mouse model, we find that these cells inhibit tumor recurrence, suggesting that senescence in response to treatment suppresses tumorigenesis. This finding, together with extensive evidence from others demonstrating that age-associated health problems develop dramatically earlier among childhood cancer survivors compared to age-matched counterparts, suggests a relationship between therapy-induced senescence and tumorigenesis. Although cancer risk is increased through accelerated premature-aging in the long run, therapy-induced senescence appears to protect survivors from recurrence, at least in the short run.

Cyclophilins (Cyp) are peptidil-prolyl-isomerases and the intracellular receptors for the immunosuppressant Cyclosporine-A (CsA), which produces epithelial-mesenchymal-transition (EMT) and renal tubule-interstitial fibrosis. Since CsA inhibits Cyp enzymatic activity, we hypothesized that Cyp could be involved in EMT and fibrosis. Here, we demonstrate that CypB is a critical regulator of tubule epithelial cell plasticity on the basis that: i) CypB silencing caused epithelial differentiation in proximal tubule-derived HK-2 cells, ii) CypB silencing prevented TGFβ-induced EMT in HK-2, and iii) CypB knockdown mice exhibited reduced UUO-induced inflammation and kidney fibrosis. By contrast, silencing of CypA induces a more undifferentiated phenotype and favors TGFβ effects. EMT mediators Slug and Snail were up-regulated in CypA-silenced cells, while in CypB silencing, Slug, but not Snail, was down-regulated; thus, reinforcing the role of Slug in kidney fibrosis. CypA regulates Slug through its PPIase activity whereas CypB depends on its ER location, where interacts with calreticulin, a calcium modulator which is involved in TGFβ signaling. In conclusion, this work uncovers new roles for CypA and CypB in modulating proximal tubular cell plasticity.

Treatment of cancer is frequently unsuccessful related to the loss of apoptotic signaling in malignant cells. This is a particular problem for high-grade gliomas, such as Glioblastoma Multiforme (GBM), which are almost universally fatal within a year or so of diagnosis. Novel therapies that capitalize on non-apoptotic cell death pathways may yield more effective outcomes, if their underlying mechanisms can be more completely deciphered. In a recent publication (ref 10), the mechanisms by which cellular cyclophilins support GBM cell survival have been identified. Inhibition of cyclophilins activated paraptosis, which relied on a combination of endoplasmic reticulum (ER) stress and transient activation of autophagy. An important aspect of this effect was the relative rates of cap-dependent versus cap-independent protein synthesis, which were differentially modulated by protein synthesis inhibitors or mTOR inhibition. Although cycloheximide has previously been characterized as an inhibitor of paraptosis, in the case of cyclophilin inhibition, it appears to significantly enhance stress-related paraptosis and cell death. This work reveals an important role for cap-independent protein translation and autophagy in the ability of GBM cells to resist non-apoptotic death, and adds to our understanding of the events that underlie paraptosis.

Medulloblastoma arising from the cerebellum is the most common pediatric brain malignancy, with leptomeningeal metastases often present at diagnosis and recurrence associated with poor clinical outcome. In this study, we used mouse medulloblastoma models to explore the relationship of tumor pathophysiology and dysregulated expression of the NOTCH pathway transcription factor ATOH1, which is present in aggressive medulloblastoma subtypes driven by aberrant Sonic Hedgehog/Patched (SHH/PTCH) signaling. In experiments with conditional ATOH1 mouse mutants crossed to Ptch1+/− mice, which develop SHH-driven medulloblastoma, animals with Atoh1 transgene expression developed highly penetrant medulloblastoma at a young age with extensive leptomeningeal disease and metastasis to the spinal cord and brain, resembling xenografts of human SHH medulloblastoma. Metastatic tumors retained abnormal SHH signaling like tumor xenografts. Conversely, ATOH1 expression was detected consistently in recurrent and metastatic SHH medulloblastoma. Chromatin immunoprecipitation sequencing and gene expression profiling identified candidate ATOH1 targets in tumor cells involved in development and tumorigenesis. Among these targets specific to metastatic tumors, there was an enrichment in those implicated in extracellular matrix remodeling activity, cytoskeletal network and interaction with microenvironment, indicating a shift in transcriptomic and epigenomic landscapes during metastasis. Treatment with bone morphogenetic protein or SHH pathway inhibitors decreased tumor cell proliferation and suppressed metastatic tumor growth, respectively. Our work reveals a dynamic ATOH1-driven molecular cascade underlying medulloblastoma metastasis that offers possible therapeutic opportunities. Cancer Res; 77(14); 3766–77. ©2017 AACR.

The di-2-pyridylketone thiosemicarbazone Dp44mT is a metal-chelating compound that has been demonstrated to have potent activity as an anticancer agent. Here we report that it also has a dramatic inhibitory effect on T-cell activation in vitro. We found that 10 nM Dp44mT (IC50 3.2 nM) prevented the up-regulation of surface CD25, and completely suppressed the activation and proliferation of splenic T cells isolated from Mus musculus that were stimulated with either T-cell receptor (TCR) cross-linking antibodies or phorbol ester plus ionomycin. In contrast, Dp44mT had no adverse effects on the survival of resting T cells. In addition, T cells stimulated in the presence of Dp44mT maintained the ability to up-regulate CD69 surface expression and secrete interleukin-2. Consistent with these observations, Dp44mT did not inhibit multiple canonical signals downstream of the TCR, including the nuclear factor of activated T cells. The effects of Dp44mT were easily mitigated by addition of nontoxic copper chelators ...

Constitutively active RAS small GTPases promote the genesis of human cancers. An important goal in cancer biology is to identify means of countervailing activated RAS signaling to reverse malignant transformation. Oncogenic K-RAS mutations are found in virtually all pancreatic adenocarcinomas, making the RAS pathway an ideal target for therapeutic intervention. How to best contravene hyperactivated RAS signaling has remained elusive in human pancreatic cancers. Guided by the Drosophila studies, we reasoned that a downstream mediator of RAS signals might be a suitable anti-RAS target. The E3 ubiquitin ligase seven in absentia (SINA) is an essential downstream component of the Drosophila RAS signal transduction pathway. Thus, we determined the roles of the conserved human homologues of SINA, SIAHs, in mammalian RAS signaling and RAS-mediated tumorigenesis. We report that similar to its Drosophila counterpart, human SIAH is also required for oncogenic RAS signaling in pancreatic cancer. Inhibiting SIAH-dependent proteolysis blocked RAS-mediated focus formation in fibroblasts and abolished the tumor growth of human pancreatic cancer cells in soft agar as well as in athymic nude mice. Given the high level of conservation of RAS and SIAH function, our study provides useful insights into altered proteolysis in the RAS pathway in tumor initiation, progression, and oncogenesis. By targeting SIAH, we have found a novel means to contravene oncogenic RAS signaling and block RAS-mediated transformation/tumorigenesis. Thus, SIAH may offer a novel therapeutic target to halt tumor growth and ameliorate RAS-mediated pancreatic cancer. [Cancer Res 2007;67(24):11798–810]

In this study, we investigated the mechanisms underlying cell death induced by the small molecule cyclophilin inhibitor NIM811. NIM811 effectively killed GBM cells through a non-apoptotic pathway, as there was no nuclear shrinkage or caspase activation. Instead, death was preceded by dramatic cytosolic vacuolization, stemming from enlargement of the endoplasmic reticulum (ER). RNA-seq revealed upregulation of genes pertinent to the unfolded protein response (UPR) and autophagy. Western blotting for UPR and autophagy mediators also supported a transient UPR signaling and compromised autophagy during prolonged NIM811 treatment. By utilizing a bicistronic reporter plasmid, we independently quantitated Cap-dependent and Cap-independent translation. We further assessed the long-term effects mediated by different short-term paraptosis inhibitors via colony formation assay. We find that NIM811 initiates paraptosis in GBM cells, due to an abnormal upregulation of protein translation that caused accumulation of misfolded or unfolded proteins in ER. Transient activation of pro-survival autophagy and UPR signals were shutdown during prolonged treatment with NIM811, thus allowing cell death to occur. Cycloheximide was previously reported by others to suppress paraptosis. In our studies, we find instead that it temporarily delayed vacuole formation, but actually enhanced paraptotic cell death in the long term. The mTOR inhibitors rapamycin or torin-2 rescued cells from NIM811 induced paraptosis by sustaining autophagy and the UPR, and specifically restrained cap-dependent translation. We propose that ER vacuolization could be a protective response generated by cells to isolate defective proteins within the ER in order to prevent misfolded aggregates to interfere with cellular homeostasis. For that reason, simply inhibiting vacuole formation without clearing protein accumulation in the ER was insufficient to prevent cell death. These findings aid our understanding of cellular mechanisms that contribute to non-apopotic death. Moreover, this work underlines the importance of evaluating cellular responses in cell death experiments over multiple time frames to judge the true impact. Citation Format: Lin Wang, Justin Gundelach, Richard Bram. Protein synthesis modulates paraptotic death induced by inhibition of cyclophilins in glioblastoma (GBM) 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 4313. doi:10.1158/1538-7445.AM2017-4313

Cancer is the second leading cause of death worldwide. Current treatment strategies based on multi-agent chemotherapy and/or radiation regimens have improved overall survival in some cases. However, resistance to apoptosis often develops in cancer cells, and its occurrence is thought to contribute to treatment failure. Non-apoptotic cell death mechanisms have become of great interest, therefore, in hopes that they would bypass tumor cell resistance. Glioblastoma multiforme (GBM), a grade IV astrocytic tumor is the most frequent brain tumor in adults, and has a high rate of mortality. We report that NIM811, a small molecule cyclophilin-binding inhibitor, induces catastrophic vacuolization and cell death in GBM cells. These unique features are distinct from many known cell death pathways, and are associated with an incompletely defined cell death mechanism known as paraptosis. We found that NIM811-induced paraptosis is due to unresolved ER stress. The abnormal upregulation of protein translation was responsible for the build-up of misfolded or unfolded proteins in ER, whereas pro-survival autophagy and UPR signals were shutdown during prolonged treatment with NIM811. Although cycloheximide has been claimed to suppress paraptosis, instead we find that it only temporarily delayed vacuole formation, but actually enhanced paraptotic cell death in the long term. On the other hand, mTOR inhibitors rescued cells from NIM811-induced paraptosis by sustaining autophagy and the UPR, while specifically restraining cap-dependent translation. These findings not only provide new insights into the mechanisms underlying paraptosis, but also shed light on a potential approach to enhance GBM treatment.