RNA Expression Signatures Research Articles

Identification and Utilization of Biomarkers to Predict Response to Immune Checkpoint Inhibitors.

Immune checkpoint inhibitors (ICPI) have revolutionized cancer therapy and provided clinical benefit to thousands of patients. Despite durable responses in many tumor types, the majority of patients either fail to respond at all or develop resistance to the ICPI. Furthermore, ICPI treatment can be accompanied by serious adverse effects. There is an urgent need for identification of patient populations that will benefit from ICPI as single agents and when used in combinations. As ICPI have achieved regulatory approvals, accompanying biomarkers including PD-L1 immunohistochemistry (IHC) and tumor mutational burden (TMB) have also received approvals for some indications. The ICPI pembrolizumab was the first example of a tissue-agnostic FDA approval based on tumor microsatellite instability (MSI)/deficient mismatch repair (dMMR) biomarker status, rather than on tumor histology assessment. Several other ICPI-associated biomarkers are in the exploratory stage, including quantification of tumor-infiltrating lymphocytes (TILs), gene expression profiling (GEP) of an inflamed microenvironment, and neoantigen prediction. TMB and PD-L1 expression can predict a subset of responses, but they fail to predict all responses to checkpoint blockade. While a single biomarker is currently limited in its ability to fully capture the complexity of the tumor-immune microenvironment, a combination of biomarkers is emerging as a method to improve predictive power. Here we review the steadily growing impact of comprehensive genomic profiling (CGP) for development and utilization of predictive biomarkers by simultaneously capturing TMB, MSI, and the status of genomic targets that confer sensitivity or resistance to immunotherapy, as well as detecting inflammation through RNA expression signatures.

Abstract 5688: IND-enabling characterization of ONC206 as the next bitopic antagonist for oncology

Abstract ONC201 is the first clinical bitopic antagonist of dopamine receptor D2 (DRD2), that is well tolerated and induces durable tumor regressions in H3 K27M-mutant glioma patients. ONC206, a derivative of ONC201 that shares the imipridone core structure, is also a bitopic DRD2 antagonist that exhibits enhanced non-competitive effects, high specificity, nanomolar potency, and disruption of DRD2 homodimers. ONC206 exhibited a Ki of ~320nM for DRD2 with complete specificity across human GPCRs and complete DRD2 antagonism. Schild analyses of ONC206 in cAMP and β-Arrestin recruitment assays revealed hallmarks of non-competitive DRD2 antagonism, unlike antipsychotics but similar to ONC201. Shotgun mutagenesis across DRD2 identified 7 residues critical for ONC206-mediated antagonism at orthosteric and allosteric sites. Six residues were critical for ONC201 and ONC206, however the impact varied between the two compounds and one allosteric residue was exclusive to ONC206 located at the region that mediates the DRD2 homodimer interface. Gene expression profiling revealed ONC206 and ONC201 (upon 200nM treatment, 72 h) induce distinct signatures in U87 glioblastoma cells, further supporting distinct functional effects. Cell lines resistant to ONC201 and ONC206 are being generated to profile acquired-resistance mechanisms. Broad nanomolar efficacy of ONC206 (GI50 <78-889nM, 72h) was observed in >1,000 GDSC cancer cell lines with the highest sensitivity in cell lines exhibiting a DRD2+/DRD5- RNA expression signature. ONC206 reduced the viability of normal human fibroblasts at higher doses (GI50 > 5µM), suggesting a wide therapeutic window. Antitumor efficacy without body weight loss was observed with 50 mg/kg weekly oral ONC206 in a dopamine-secreting HuCCT1 cholangiocarcinoma subcutaneous xenograft model. Oral ONC206 at 50mg/kg exhibited a ~12 µM plasma Cmax and ~6 hours terminal half-life in Sprague-Dawley rats. Additionally, 5-10 fold higher ONC206 concentrations were observed in adrenal gland, bile duct, brain and bone marrow relative to plasma. Nanomolar concentrations were also observed in the CSF above DRD2 antagonism thresholds, unlike ONC201. GLP toxicology studies with weekly oral ONC206 in Sprague-Dawley rats and beagle dogs revealed no dose-limiting toxicities. Mild and reversible body weight changes were observed at the highest evaluated dose in both species. The no observed adverse effect level was ≥ 16.7 mg/kg in dogs and ≥ 50 mg/kg in rats that exceed efficacious doses. A 50 mg starting dose of ONC206 was selected for the first-in-human clinical trial in biomarker-enriched adult recurrent CNS tumors. In summary, ONC206 is poised for clinical introduction as the next imipridone bitopic DRD2 antagonist for oncology that exhibits differentiated target engagement, signaling, and biodistribution profiles. Citation Format: Varun Vijay Prabhu, Sara Morrow, Caroline A. Cuoco, Abed R. Kawakibi, Jinkyu Jung, Neel Madhukar, Matthew J. Garnett, Ultan McDermott, Cyril H. Benes, Robert Wechsler-Reya, Lakshmi Anantharaman, Neil Charter, Joseph B. Rucker, Benjamin J. Doranz, Joel Basken, Olivier Elemento, R. Benjamin Free, David R. Sibley, Martin Stogniew, Wolfgang Oster, Mark R. Gilbert, Sharon DeMorrow. IND-enabling characterization of ONC206 as the next bitopic antagonist for oncology [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5688.

Expression profile analysis to identify circular RNA expression signatures in hair follicle of Hu sheep lambskin

CircRNAs are involved in the regulation of various cellular and biological processes, but none of the studies have focused on hair follicle in sheep. In this study, the expression profile of circRNAs between small waves (SM) and straight wool (ST) groups was investigated using RNA-Seq. The results showed that a total of 5,527 circRNAs were identified and 114 of them were differentially expressed between two groups. Enrichment analysis revealed that the host genes with DE circRNAs were mainly enriched in TGF-beta pathway, Notch pathway. Miranda software was used to found that 129 miRNAs might be binding to 114 DE circRNAs, including miR-10a, miR-143, miR-let-7a, miR-199a-3p, miR-200a, which also had important influence on hair follicle morphogenesis. Furthermore, the coding potential of circRNAs was predicted, and 11 circRNAs were simultaneously identified with coding potential. In summary, circRNAs have important effects on hair follicle growth and development, and these results will provide a basis for molecular mechanism of pattern formation.

Chromosomal instability in untreated primary prostate cancer as an indicator of metastatic potential

BackgroundMetastatic prostate cancer (PC) is highly lethal. The ability to identify primary tumors capable of dissemination is an unmet need in the quest to understand lethal biology and improve patient outcomes. Previous studies have linked chromosomal instability (CIN), which generates aneuploidy following chromosomal missegregation during mitosis, to PC progression. Evidence of CIN includes broad copy number alterations (CNAs) spanning > 300 base pairs of DNA, which may also be measured via RNA expression signatures associated with CNA frequency. Signatures of CIN in metastatic PC, however, have not been interrogated or well defined. We examined a published 70-gene CIN signature (CIN70) in untreated and castration-resistant prostate cancer (CRPC) cohorts from The Cancer Genome Atlas (TCGA) and previously published reports. We also performed transcriptome and CNA analysis in a unique cohort of untreated primary tumors collected from diagnostic prostate needle biopsies (PNBX) of localized (M0) and metastatic (M1) cases to determine if CIN was linked to clinical stage and outcome.MethodsPNBX were collected from 99 patients treated in the VA Greater Los Angeles (GLA-VA) Healthcare System between 2000 and 2016. Total RNA was extracted from high-grade cancer areas in PNBX cores, followed by RNA sequencing and/or copy number analysis using OncoScan. Multivariate logistic regression analyses permitted calculation of odds ratios for CIN status (high versus low) in an expanded GLA-VA PNBX cohort (n = 121).ResultsThe CIN70 signature was significantly enriched in primary tumors and CRPC metastases from M1 PC cases. An intersection of gene signatures comprised of differentially expressed genes (DEGs) generated through comparison of M1 versus M0 PNBX and primary CRPC tumors versus metastases revealed a 157-gene “metastasis” signature that was further distilled to 7-genes (PC-CIN) regulating centrosomes, chromosomal segregation, and mitotic spindle assembly. High PC-CIN scores correlated with CRPC, PC-death and all-cause mortality in the expanded GLA-VA PNBX cohort. Interestingly, approximately 1/3 of M1 PNBX cases exhibited low CIN, illuminating differential pathways of lethal PC progression.ConclusionsMeasuring CIN in PNBX by transcriptome profiling is feasible, and the PC-CIN signature may identify patients with a high risk of lethal progression at the time of diagnosis.

Genome-wide analysis of lncRNAs, miRNAs, and mRNAs forming a prognostic scoring system in esophageal squamous cell carcinoma

BackgroundEsophageal squamous cell carcinoma (ESCC) is the main subtype of esophageal carcinoma. Protein coding genes and non-coding RNAs can be powerful prognostic factors in multiple cancers, including ESCC. However, there is currently no model that integrates multiple types of RNA expression signatures to predict clinical outcomes.MethodsThe sequencing data (RNA-sequencing and miRNA-sequencing) and clinical data of ESCC patients were obtained from The Cancer Genome Atlas (TCGA) database, and Differential gene expression analysis, Cox regression analysis and Spearman correlation analysis were used to construct prognosis-related lncRNA-mRNA co-expression network and scoring system with multiple types of RNA. The potential molecular mechanisms of prognostic mRNAs were explored by functional enrichment analysis.ResultsA total of 62 prognostic lncRNAs, eight prognostic miRNAs and 66 prognostic mRNAs were identified in ESCC (P-value < 0.05) and a prognosis-related lncRNA-mRNA co-expression network was created. Five prognosis-related hub RNAs (CDCA2, MTBP, CENPE, PBK, AL033384.1) were identified. Biological process analysis revealed that mRNAs in prognosis-related co-expression RNA network were mainly enriched in cell cycle, mitotic cell cycle and nuclear division. Additionally, we constructed a prognostic scoring system for ESCC using ten signature RNAs (MLIP, TNFSF10, SIK2, LINC01068, LINC00601, TTTY14, AC084262.1, LINC01415, miR-5699-3p, miR-552-5p). Using this system, patients in the low-risk group had better long-term survival than those in the high-risk group (log-rank, P-value < 0.0001). The area under the ROC curve (AUCs) revealed that the accuracy of the prediction model was higher than the accuracy of single type of RNA prediction model.ConclusionIn brief, we constructed a prognostic scoring system based on multiple types of RNA for ESCC that showed high predicting prognosis performance, and deeply understood the regulatory mechanism of prognosis-related lncRNA-mRNA co-expression network.

Combinatorial Discriminant Analysis Applied to RNAseq Data Reveals a Set of 10 Transcripts as Signatures of Exposure of Cattle to Mycobacterium avium subsp. paratuberculosis.

Simple SummaryParatuberculosis or Johne’s disease (JD) in cattle is a chronic granulomatous gastroenteritis caused by infection with Mycobacterium avium subspecies paratuberculosis (MAP). JD is not treatable; therefore, the early identification of infected animals is a key point in reducing its incidence worldwide. In this paper, combinatorial discriminant analysis was applied to transcriptomic data to find a small set of differentially expressed genes able to discriminate between exposed cattle from non-exposed animals. Results of the discriminant analysis identified 10 transcripts that differentiate between ELISA-negative animals belonging to paratuberculosis-positive herds that were potentially exposed to MAP and negative-unexposed animals belonging to paratuberculosis-negative herds. The 10 transcript signature was also used for the classification of 5 cattle positive-for-MAP infection samples, with the underlying hypothesis that their transcriptional profile should be closer to potentially exposed animals than to controls. The same set of 10 transcripts was able to differentiate ELISA-negative unexposed animals from positive animals based on the results of the ELISA test for bovine paratuberculosis and faecal culture. In conclusion, these findings suggest the possible use of the identified RNA expression signature as a new diagnostic test for paratuberculosis. Paratuberculosis or Johne’s disease in cattle is a chronic granulomatous gastroenteritis caused by infection with Mycobacterium avium subspecies paratuberculosis (MAP). Paratuberculosis is not treatable; therefore, the early identification and isolation of infected animals is a key point to reduce its incidence. In this paper, we analyse RNAseq experimental data of 5 ELISA-negative cattle exposed to MAP in a positive herd, compared to 5 negative-unexposed controls. The purpose was to find a small set of differentially expressed genes able to discriminate between exposed animals in a preclinical phase from non-exposed controls. Our results identified 10 transcripts that differentiate between ELISA-negative, clinically healthy, and exposed animals belonging to paratuberculosis-positive herds and negative-unexposed animals. Of the 10 transcripts, five (TRPV4, RIC8B, IL5RA, ERF, CDC40) showed significant differential expression between the three groups while the remaining 5 (RDM1, EPHX1, STAU1, TLE1, ASB8) did not show a significant difference in at least one of the pairwise comparisons. When tested in a larger cohort, these findings may contribute to the development of a new diagnostic test for paratuberculosis based on a gene expression signature. Such a diagnostic tool could allow early interventions to reduce the risk of the infection spreading.

Abstract WMP61: RNA Expression Signature to Diagnosis Stroke Etiology by Atrial Fibrillation versus Large Artery Atherosclerosis Cause: A BASE Clinical Trial Analysis

Background: Identifying atrial fibrillation in embolic stroke of ischemic stroke populations would be of significant clinical utility. Using the Biomarkers of Acute Stroke Etiology (BASE) trial (NCT02014896) dataset, our goal was to determine if blood gene expression signatures accurately differentiated patients with atrial fibrillation from large artery stroke patients. Methods: The BASE trial enrolled suspected stroke patients presenting to 20 hospitals within 24 hrs of symptom onset. Final gold standard diagnosis and stroke etiology were determined by an adjudication committee using all hospital data but blinded to RNA test results. Whole blood, obtained in PAXgene tubes, was frozen at -20C within 72 hrs and analyzed at a core lab (Ischemia Care, LLC, Dayton, OH) using Affymetrix HTA micro arrays. Approximately 38,000 genes on the HTA microarray were filtered to eliminate genes with low expression or high CV (&gt; 10%) when run on replicate samples leaving 9,513 potential signature genes. A two-way random forest classifier was built through cross validation of the training data resulting in a 23 gene diagnostic signature. Results: There were 58 patients enrolled between 18 and 24 hours of symptom onset, with NIHSS&gt;5, 27 (47%) with atrial fibrillation cause of stroke and 31 (53%) with large artery stroke; 64% were male, and median (IQR) age was 69.7 (62.8, 81.0). Median (IQR) time from symptoms to sample collection was 1323.5 (1208.8, 1381.3) minutes. Coexistent pathology at presentation was high blood pressure 49 (84%), hyperlipidemia 28 (48%), diabetes 9 (16%), and coronary artery disease 15 (26%). The panel was able to distinguish atrial fibrillation from large vessel stroke with a C-statistic 0.92 (0.55-1.0, 95% CI), sensitivity 0.90 (0.51-1.0, 95% CI) and specificity of 0.85. Conclusion: RNA expression differentiates strokes due to atrial fibrillation from large artery stroke and may have therapeutic and outcome implications in ischemic stroke populations.

Literature review and methodological considerations for understanding circulating risk biomarkers following trauma exposure.

Exposure to traumatic events is common. While many individuals recover following trauma exposure, a substantial subset develop adverse posttraumatic neuropsychiatric sequelae (APNS) such as posttraumatic stress, major depression, and regional or widespread chronic musculoskeletal pain. APNS cause substantial burden to the individual and to society, causing functional impairment and physical disability, risk for suicide, lost workdays, and increased health care costs. Contemporary treatment is limited by an inability to identify individuals at high risk of APNS in the immediate aftermath of trauma, and an inability to identify optimal treatments for individual patients. Our purpose is to provide a comprehensive review describing candidate blood-based biomarkers that may help to identify those at high risk of APNS and/or guide individual intervention decision-making. Such blood-based biomarkers include circulating biological factors such as hormones, proteins, immune molecules, neuropeptides, neurotransmitters, mRNA and noncoding RNA expression signatures, while we do not review genetic and epigenetic biomarkers due to other recent reviews of this topic. The current state of the literature on circulating risk biomarkers of APNS is summarized, and key considerations and challenges for their discovery and translation are discussed. We also describe the AURORA study, a specific example of current scientific efforts to identify such circulating risk biomarkers and the largest study to date focused on identifying risk and prognostic factors in the aftermath of trauma exposure.

Phase II Study of the Hyper-CVAD Regimen in Combination with Ofatumumab (HCVAD-O) As Frontline Therapy for Adult Patients (pts) with CD20-Positive B-Cell Acute Lymphoblastic Leukemia (B-ALL)

Phase II Study of the Hyper-CVAD Regimen in Combination with Ofatumumab (HCVAD-O) As Frontline Therapy for Adult Patients (pts) with CD20-Positive B-Cell Acute Lymphoblastic Leukemia (B-ALL)

EXTH-71. IND-ENABLING CHARACTERIZATION OF ONC206 AS THE NEXT BITOPIC DRD2 ANTAGONIST FOR NEURO-ONCOLOGY

Abstract ONC201 is the first clinical bitopic antagonist of DRD2, an oncogenic receptor in brain and neuroendocrine tumors. ONC206, a derivative of ONC201 that shares the imipridone core structure, is also a bitopic DRD2 antagonist that exhibits enhanced non-competitive effects, high specificity, nanomolar potency, and disruption of DRD2 homodimers. Broad nanomolar efficacy of ONC206 (GI50 &lt; 78-889nM, CellTitre-Glo, 72h) was observed in &gt;1,000 GDSC cancer cell lines. Maximal ONC206 sensitivity was observed in pheochromocytoma, high-grade gliomas, neuroblastoma, medulloblastoma, sarcoma and cholangiocarcinoma cell lines exhibiting a DRD2+/DRD5- RNA expression signature. An exposure time of 48h at nanomolar concentrations was sufficient for maximal inhibition of tumor cell viability. ONC206 reduced the viability of normal human fibroblasts at higher doses (GI50 &gt; 5µM), suggesting a wide therapeutic window. Antitumor efficacy without body weight loss was observed with 50 mg/kg weekly oral ONC206 in a dopamine-secreting HuCCT1 cholangiocarcinoma subcutaneous xenograft model. Biodistribution studies in Sprague-Dawley rats revealed a ~12 µM plasma Cmax with a systemic terminal half-life of ~6 hours upon a single oral dose of 50 mg/kg. Additionally, 5–10 fold higher ONC206 concentrations were observed in adrenal gland, bile duct, brain and bone marrow relative to plasma. Nanomolar concentrations were also observed in the CSF above DRD2 antagonism thresholds, unlike ONC201. GLP toxicology studies with weekly oral ONC206 in Sprague-Dawley rats and beagle dogs revealed no dose-limiting toxicities. Mild and reversible decreased body weight and/or body weight gain with no effects on food consumption were observed at the highest evaluated dose in both species. The highest non-severely toxic dose (HNSTD) was ≥ 16.7 mg/kg in dogs and ≥ 50 mg/kg in rats that exceeds efficacious doses in preclinical models. Using standard allometric scaling, a 90 mg starting dose of ONC206 was selected for the first-in-human clinical trial in biomarker-defined adult recurrent CNS tumors.

RAL GTPases mediate multiple myeloma cell survival and are activated independently of oncogenic RAS.

Oncogenic RAS provides crucial survival signaling for up to half of multiple myeloma (MM) cases, but has so far remained a clinically undruggable target. RAS-like protein (RAL) is a member of the RAS superfamily of small GTPases and is considered to be a potential mediator of oncogenic RAS signaling. In primary MM, we found RAL to be overexpressed in the vast majority of samples when compared with pre-malignant monoclonal gammopathy of undetermined significance or normal plasma cells. We analyzed the functional effects of RAL abrogation in myeloma cell lines and found that RAL is a critical mediator of survival. RNAi-mediated knockdown of RAL resulted in rapid induction of tumor cell death, an effect which was independent from signaling via mitogen-activated protein kinase, but appears to be partially dependent on Akt activity. Notably, RAL activation was not correlated with the presence of activating RAS mutations and remained unaffected by knockdown of oncogenic RAS. Furthermore, transcriptome analysis yielded distinct RNA expression signatures after knockdown of either RAS or RAL. Combining RAL depletion with clinically relevant anti-myeloma agents led to enhanced rates of cell death. Our data demonstrate that RAL promotes MM cell survival independently of oncogenic RAS and, thus, this pathway represents a potential therapeutic target in its own right.

1926P - Development and validation of an RNA-seq based prognostic signature in neuroblastoma

BackgroundCredible prognostic stratification remains a challenge for neuroblastoma (NBL) with variable clinical manifestations. RNA expression signatures might predict the outcomes; notwithstanding, independent cross-platform validation is still rare. MethodsRNA expression data were obtained from NBL patients and then analyzed. In TARGET-NBL data, an RNA-based prognostic signature was developed and validated. Survival prediction was assessed using a time-dependent receiver operating characteristic (ROC) curve. Functional enrichment analysis of the RNAs was conducted using bioinformatics methods. ResultsA total of 1,119 differentially expressed RNAs and 149 prognosis-related RNAs were identified sequentially. Then, in the training cohort, 12 RNAs were identified as significantly associated with overall survival (OS) and were combined to develop a model that stratified NBL patients into low- and high-risk groups. Twelve RNA signature high-risk patients had poorer OS in the training cohort (n=105, Hazard Ratios (HR)= 0.10 (0.05-0.20), P<0.001) and in the validation cohort (n=44, HR=0.25 (0.09-0.69), P=0.008). ROC curve analysis also showed that both the training and validation cohorts performed well in predicting OS (12-month AUC values of 0.852 and 0.438, 36-month AUC values of 0.824 and 0.737, and 60-month AUC values of 0.802 and 0.702, respectively). Moreover, these 12 RNAs may be involved in certain events that are known to be associated with NBL through functional enrichment analysis. ConclusionsThis study identified and validated a novel 12-RNA prognostic signature to reliably distinguish NBL patients at low and high risk of death. Further larger, multicenter prospective studies are desired to validate this model. Legal entity responsible for the studyThe authors. FundingNational Natural Science Foundation of China (Grant No. 81660512). DisclosureAll authors have declared no conflicts of interest.

P6449Circulating long noncoding RNA expression signature as a novel biomarker for myocardial fibrosis

Abstract Background Cardiac fibrosis (CF) plays a critical role in the pathogenesis of heart failure (HF), predisposing to contractile dysfunction, myocardial stiffness and life-threatening arrhythmias. Early detection and intervention of myocardial fibrosis, therefore, can delay or prevent the progression of HF. Current diagnostic and treatment options for CF, however, are very limited. Purpose To test the hypothesis that circulating lncRNA expression signature can be a sensitive biomarker to diagnose and correlate with the extent of CF in human heart. Methods Plasma RNA samples from healthy control (n=23) and from patients with diffuse myocardial fibrosis documented by cardiac magnetic resonance (T1 mapping technique, n=16) were analyzed by RNA sequencing (RNASeq), followed by differential expression, gene ontology/pathway and receiver operating characteristic (ROC) curve analyses. Results RNASeq revealed that 439 mRNAs were differentially expressed in the plasma from patients with CF, compared to that from controls. Gene ontology analyses showed significant enrichment of these CF-linked genes in cytoskeleton organization, innate immune response, and MAPK-Erk signaling, cellular processes known to contribute to the development of CF. Further analyses showed that 84 plasma lncRNAs were dysregulated in patients with CF; 5 of the lncRNAs (ENSGehz746.10420265401.1, ENSGehz746.10420229124.6, ENSGehz746.10420281376.1, ENSGehz746.10420273275.1 and ENSGehz746.10420179818.13) showed concordant changes with their cis-mRNA (UBB, VIM, BCL2L1, PPP3R1 and PCBP1). Hierarchical clustering analyses demonstrated that the expression signature of plasma lncRNAs could distinguish patients with CF from control patients (classification accuracy 87%). The expression levels of plasma lncRNAs ENSGehz746.10420258017.1 and ENSGehz746.10420265401.1, in particular, were markedly downregulated in patients with myocardial fibrosis. ROC curve analyses showed that low expression levels of ENSGehz746.10420258017.1 and ENSGehz746.10420265401.1 were highly sensitive and specific to detect the presence of CF in human heart (AUC 0.9 for both lncRNAs, Figure). LncRNA Predicts Cardiac Fibrosis Conclusions The present study revealed a circulating transcriptome signature that reflects the pathogenesis of CF. The expression profiles of circulating lncRNAs discriminated between patients with and without interstitial myocardial fibrosis. LncRNAs ENSGehz746.10420258017.1 and ENSGehz746.10420265401.1, in particular, are novel biomarkers with potential to facilitate clinical diagnosis of myocardial fibrosis.

931P - Potential role of a clinical, taxonomical classification and RNA expression integrated signature to predict response to neoadjuvant platinum-based chemotherapy in muscle-invasive bladder cancer (MIBC) patients

BackgroundNeoadjuvant chemotherapy (NAC) followed by cystectomy is the standard of care in MIBC patients, although a limited survival benefit has been obtained compared with cystectomy alone. Pathologic response has been associated with survival, but, unfortunately, neither baseline clinical or pathological variables have demonstrated ability to predict which patients will benefit from NAC, pointing to the need of predictive biomarkers of NAC response to guide treatment decisions. The objective of this retrospective study was to identify a NAC response prediction signature integrating baseline clinical features, taxonomic subtypes, and RNA expression profile in MIBC patients. MethodsFormalin-fixed paraffin-embedded pre-treatment tumor samples were collected by transurethral resection from 112 patients with MIBC stage T2-4N0/+M0 treated with NAC followed by cystectomy. Immunohistochemical-based taxonomic subtypes (BASQ-like, luminal-like, mixed) were established. Gene expression analysis was performed on the Nano String nCounter platform. A custom code set of a 41-gene panel involved in the DNA damage repair (DDR) and immune response pathways was used. Lasso and elastic net penalized logistic regression were performed to identify a predictive signature. Calculation of the area under the ROC curve (AUC) was used to assess the predictive ability of the signature. ResultsA nine-gene RNA expression signature (RAD51, CXCL9, PARP, 53BP1, HERC2, ERCC2, CHEK1, Ku80 and RNF 168 genes) was associated with pathologic response. The highest predictive ability was observed with the integrated clinical-taxonomical-RNA signature with an AUC of 0.66, in comparison to the clinical-taxonomical classification (AUC=0.58) or the clinical signature alone (AUC=0.52). Furthermore, the integrated signature was significantly associated with overall survival (p=0.013). ConclusionsWe have identified a nine-gene RNA expression signature that can help to predict response in MIBC patients treated with NAC. Prospective studies are warranted to validate these results. Legal entity responsible for the studyThe authors. FundingAECC. DisclosureAll authors have declared no conflicts of interest.

OS1.2 Development and Validation of a RNA-Seq Based Prognostic Signature in Neuroblastoma

Abstract BACKGROUND Credible prognostic stratification remains a challenge for neuroblastoma (NBL) with variable clinical manifestations. RNA expression signatures might predict the outcomes; notwithstanding, independent cross-platform validation is still rare. MATERIAL AND METHODS expression data were obtained from NBL patients and then analyzed. In TARGET-NBL data, an RNA-based prognostic signature was developed and validated. Survival prediction was assessed using a time-dependent receiver operating characteristic (ROC) curve. Functional enrichment analysis of the RNAs was conducted using bioinformatics methods. RESULTS A total of 1,119 differentially expressed RNAs and 149 prognosis-related RNAs were identified sequentially. Then, in the training cohort, 12 RNAs were identified as significantly associated with overall survival (OS) and were combined to develop a model that stratified NBL patients into low- and high-risk groups. Twelve RNA signature high-risk patients had poorer OS in the training cohort (n = 105, Hazard Ratios (HR)= 0.10 (0.05–0.20), P &lt; 0.001) and in the validation cohort (n = 44, HR = 0.25 (0.09–0.69), P = 0.008). ROC curve analysis also showed that both the training and validation cohorts performed well in predicting OS (12-month AUC values of 0.852 and 0.438, 36-month AUC values of 0.824 and 0.737, and 60-month AUC values of 0.802 and 0.702, respectively). Moreover, these 12 RNAs may be involved in certain events that are known to be associated with NBL through functional enrichment analysis. CONCLUSION This study identified and validated a novel 12-RNA prognostic signature to reliably distinguish NBL patients at low and high risk of death. Further larger, multicenter prospective studies are desired to validate this model.

Discovery and cross-validation of peripheral blood and renal biopsy gene expression signatures from ethnically diverse kidney transplant populations.

We determined peripheral blood (PB) and biopsy (Bx) RNA expression signatures in a Brazilian and US cohort of kidney transplant patients. Phenotypes assigned by precise histology were: acute rejection (AR), interstitial fibrosis/tubular atrophy/chronic rejection (CR), excellent functioning transplants (TX), and glomerulonephritis recurrence (GN). Samples were analyzed on microarrays and profiles from each cohort were cross-validated on the other cohort with similar phenotypes. We discovered signatures for each tissue: (1) AR vs TX, (2) CR vs TX, and (3) GN vs TX using the Random Forests algorithm. We validated biopsies signatures of AR vs TX (area under the curve [AUC] 0.97) and CR vs TX (AUC 0.87). We also validated both PB and Bx signatures of AR vs TX and CR vs TX with varying degrees of accuracy. Several biological pathways were shared between AR and CR, suggesting similar rejection mechanisms in these 2 clinical phenotypes. Thus, we identified gene expression signatures for AR and CR in transplant patients and validated them in independent cohorts of significantly different racial/ethnic backgrounds. These results reveal that there are strong unifying immune mechanisms driving transplant diseases and identified in the signatures discovered in each cohort, suggesting that molecular diagnostics across populations are feasible despite ethnic and environmental differences.

Abstract 3877: IND-enabling characterization of DRD2/3 imipridone antagonist ONC206 for oncology

Abstract Dopamine receptor D2 (DRD2) is a G protein-coupled receptor that is overexpressed and critical for survival in several cancers. ONC201, an imipridone small molecule, is a DRD2/3 antagonist in Phase II advanced cancer clinical trials with a compelling safety and efficacy profile. We evaluated the binding target, anti-tumor activity, biodistribution and safety of ONC206, a chemical derivative of ONC201 with the same imipridone core structure. GPCR profiling with β-Arrestin recruitment revealed that ONC206 selectively antagonizes dopamine receptors DRD2 and DRD3. ONC206 exhibited a Ki of ~320nM for DRD2 with complete specificity across human GPCRs and complete DRD2 antagonism. Schild analyses of ONC206 in cAMP and β-Arrestin recruitment assays revealed hallmarks of non-competitive DRD2 antagonism, unlike antipsychotics but similar to ONC201. Shotgun mutagenesis across DRD2 identified 7 residues critical for ONC206-mediated antagonism at orthosteric and allosteric sites. While 6 mutated residues were also critical for ONC201-mediated antagonism, the impact and magnitude of different mutants varied between the two compounds and one of the allosteric residues was unique to ONC206. In vitro profiling of ONC206 in &amp;gt;1000 GDSC cancer cell lines demonstrated broad nanomolar efficacy (GI50 &amp;lt;78-889nM). TCGA and tissue microarrays analyses revealed that malignant DRD2 expression was highest in pheochromocytoma, high grade gliomas, neuroblastoma, medulloblastoma, Ewing’s sarcoma and cholangiocarcinoma. Accordingly, ONC206 demonstrated nanomolar in vitro sensitivity in these tumor types. Similar to ONC201, a DRD2+/DRD5- RNA expression signature in the GDSC panel predicted significantly enhanced ONC206 sensitivity. ONC206 reduced the viability of normal human fibroblasts at micromolar doses (GI50 &amp;gt; 5µM), suggesting a wide therapeutic window. Robust inhibition of tumor growth without body weight loss was observed in HuCCT1 cholangiocarcinoma and MHH-ES-1 Ewing’s sarcoma subcutaneous xenografts with 50-100 mg/kg oral ONC206 weekly or every 2 weeks. Biodistribution studies in Sprague-Dawley rats revealed a ~12 µM plasma Cmax with a half-life of ~6 hours upon a single oral dose of 50 mg/kg. Additionally, 5-10 fold higher ONC206 concentrations were observed in adrenal gland, bile duct, brain and bone marrow relative to plasma concentrations. GLP toxicology studies with weekly oral ONC206 in Sprague-Dawley rats and beagle dogs at doses above or equivalent to efficacious doses revealed no dose-limiting toxicities. In both species, observations at the highest dose were mild and reversible. The no observed adverse event level (NOAEL) was ≥ 16.7 mg/kg in dogs and ≥ 50 mg/kg in rats, which both correspond to a human dose of approximately 500 mg assuming standard allometric scaling. These results provide rationale for a 50 mg starting ONC206 dose in dose escalation clinical trials in patients with DRD2-dysregulated tumors. Citation Format: Varun V. Prabhu, Abed Rahman Kawakibi, Neel Madhukar, Mathew J. Garnett, Ultan McDermott, Cyril H. Benes, Lakshmi Anantharaman, Neil Charter, Sean Deacon, Alexander VanEngelenburg, Joseph B. Rucker, Benjamin J. Doranz, Jessica Rusert, Robert Wechsler-Reya, Olivier Elemento, Martin Stogniew, Wolfgang Oster, Sharon DeMorrow, R. Benjamin Free, David R. Sibley, Joshua E. Allen. IND-enabling characterization of DRD2/3 imipridone antagonist ONC206 for oncology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3877.

Abstract LB-029: Identification of predictive genetic signatures of Cytarabine responsiveness in acute myeloid leukemia using a novel 3D translational culture model of primary bone marrow

Abstract Acute myeloid leukemia (AML) is a malignancy with complex genetics, poor survival rates and high rates of chemotherapy resistance. This study reports the establishment of a novel bone marrow mononuclear cell 3D-culture model and the application of this model to define sensitivity and resistance biomarkers as evident by DNA and RNA expression signatures in response to standard Cytarabine (Ara-C) chemotherapy. By simulating the bone marrow microenvironment, we optimized the growth conditions using frozen bone marrow mononuclear cells (BMMC) derived from healthy donors. We validated our platform by demonstrating that healthy BMMCs are capable of differentiating into all hematopoietic lineages and various types of stromal cells. Using this platform, we then characterized BMMC samples from 47 AML patients. Sixty percent of AML samples were capable of proliferating and 23 samples demonstrated robust growth. RNA sequencing was performed for 3D and 2D cultures to determine which conditions are superior at maintaining original gene expression signatures as compared to the uncultured bone marrow, To elucidate specific genetic mutations and/or gene expression signatures associated with the ability of ex vivo growth of these AML donors, whole exosome sequencing and RNA Sequencing were performed. The model identified unique gene expression signatures that correlated with sensitive as well as resistant donors in response to Ara-C treatment. These data demonstrate the translational value of our platform which should be widely applicable to evaluate other therapies in AML. Citation Format: Haiyan Xu, Eric S. Muise, Sarah Javaid, Lan Chen, Razvan Cristescu, My Sam Mansueto, Nicole Follmer, Jennifer Cho, Kimberley Kerr, Rachel Altura, Michelle Machacek, Benjamin Nicholson, George Addona, Ilona Kariv, Hongmin Chen. Identification of predictive genetic signatures of Cytarabine responsiveness in acute myeloid leukemia using a novel 3D translational culture model of primary bone marrow [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-029.

Integrated Analysis of TP53 Gene and Pathway Alterations in The Cancer Genome Atlas

The TP53 tumor suppressor gene is frequently mutated in human cancers. An analysis of five data platforms in 10,225 patient samples from 32 cancers reported by The Cancer Genome Atlas (TCGA) enables comprehensive assessment of p53 pathway involvement in these cancers. More than 91% of TP53-mutant cancers exhibit second allele loss by mutation, chromosomal deletion, or copy-neutral loss of heterozygosity. TP53 mutations are associated with enhanced chromosomal instability, including increased amplification of oncogenes and deep deletion of tumor suppressor genes. Tumors with TP53 mutations differ from their non-mutated counterparts in RNA, miRNA, and protein expression patterns, with mutant TP53 tumors displaying enhanced expression of cell cycle progression genes and proteins. A mutant TP53 RNA expression signature shows significant correlation with reduced survival in 11 cancer types. Thus, TP53 mutation has profound effects on tumor cell genomic structure, expression, and clinical outlook.

LncRNA Profile Study Reveals a Three-LncRNA Signature Associated With the Pathological Complete Response Following Neoadjuvant Chemotherapy in Breast Cancer.

BackgroundThe purpose of this study is to develop an effective but concise long non-coding RNA (lncRNA) expression signature that can predict response to neoadjuvant chemotherapy for breast cancer (BC) patients.MethodslncRNA expression profiling in 1102 BC patients from Gene Expression Omnibus datasets was analyzed using lncRNA-mining approach. The association between lncRNA signature and pathological complete response (pCR) was analyzed using logistic regression model in the training set (GSE25066, n = 488). Validation was performed in independent testing datasets, GSE20194, GSE20271, GSE22093, and GSE23988 (n = 614). Bonferroni method was employed for multiple testing corrections. Cell proliferation assay and Western blot assay were performed to evaluate the cell viability and protein expression level, respectively.ResultsThree lncRNAs (AK291479, U79293, and BC032585) have been identified to be significantly associated with pCR in the training dataset (Bonferroni p-value < 0.05). Expression signature with these lncRNAs was predictive of pCR in the training (AUC = 0.74) and testing (AUC = 0.72) datasets. Weighted gene co-expression network analysis and gene functional annotation suggest that the three lncRNAs were involved in cell cycle process. To confirm the functional significance of the identified lncRNAs, BC032585 was selectively silenced using RNA interference. Knockdown of BC032585 lncRNA significantly promoted cell resistance to multiple anticancer-drugs through upregulating MDR1 expression in breast cancer cells.ConclusionThese results suggest that lncRNAs such as BC032585 might be involved in chemotherapeutic response in breast cancer patients, and the three-lncRNA signature identified in the present study may serve as a useful biomarker for the selection of responsive breast cancer patients in neoadjuvant chemotherapy.