Search

Neuroblastoma is a deadly pediatric solid tumor with infrequent recurrent somatic mutations. Particularly, the pathophysiology of tumors without MYCN amplification remains poorly defined. Utilizing an unbiased approach, we performed gene set enrichment analysis of RNA-sequencing data from 498 patients with neuroblastoma and revealed a differentially overexpressed gene signature in MYCN nonamplified neuroblastomas with telomerase reverse transcriptase (TERT) gene overexpression and coordinated activation of oncogenic signaling pathways, including E2Fs, Wnt, Myc, and the DNA repair pathway. Promoter rearrangement of the TERT gene juxtaposes the coding sequence to strong enhancer elements, leading to TERT overexpression and poor prognosis in neuroblastoma, but TERT-associated oncogenic signaling remains unclear. ChIP-seq analysis of the human CLB-GA neuroblastoma cells harboring TERT rearrangement uncovered genome-wide chromatin co-occupancy of Brd4 and H3K27Ac and robust enrichment of H3K36me3 in TERT and multiple TERT-associated genes. Brd4 and cyclin-dependent kinases (CDK) had critical regulatory roles in the expression and chromatin activation of TERT and multiple TERT-associated genes. Epigenetically targeting Brd4 or CDKs with their respective inhibitors suppressed the expression of TERT and multiple TERT-associated genes in neuroblastoma with TERT overexpression or MYCN amplification. ChIP-seq and ChIP-qPCR provided evidence that the CDK inhibitor directly inhibited Brd4 recruitment to activate chromatin globally. Therefore, inhibiting Brd4 and CDK concurrently with AZD5153 and dinaciclib would be most effective in tumor growth suppression, which we demonstrated in neuroblastoma cell lines, primary human cells, and xenografts. In summary, we describe a unique mechanism in neuroblastoma with TERT overexpression and an epigenetically targeted novel therapeutic strategy.Significance:Epigenetically cotargeting Brd4 and Cdks suppresses human neuroblastoma with TERT overexpression by inhibiting the TERT-associated gene expression networks.

Supplementary Fig. S1. Elevated mRNA expression of TERT and TERT-associated genes in NB with TERT gene rearrangement. Supplementary Fig. S2. Effects of dinaciclib on genome-wide chromatin occupancy of epigenetic modulators in CLB-GA cells. Supplementary Fig. S3: C-Myc and MYCN protein expression in four NB cell lines. Supplementary Fig. S4: Effects of dinaciclib on the chromatin occupancy of epigenetic modulators at Dvl2, AURKA, and AURKB and in CLB-GA cells. Supplementary Fig. S5. Association of overexpression of FEN1, BIRC5, and UHRF1 with poor prognosis and effects of dinaciclib on chromatin occupancy of epigenetic modulators in CLB-GA cells. Supplementary Fig. S6. JQ1 sensitive Brd4 binding profiles in OCI-AML3 cells. Supplementary Fig. S7. JQ1 and dinaciclib are synergistic or additive in inducing cytotoxicity in NB cell lines. Supplementary Fig. S8. Combination index (CI) values for synergy experiment combining Dinaciclib with Brd4 inhibitor JQ1. Supplementary Fig. S9. Effects of dinaciclib on phosphorylation of Rb in CLB-GA and Kelly cells. Supplementary table S1. Primer sequences used in ChIP-qPCR and real-time RT-PCR analysis. Supplementary table 2. Gene sets enriched in NB patients with TERT gene rearrangement (n=32) versus without TERT gene rearrangement (n=278) within MYCN non-amplified NB of Tumor Neuroblastoma (TERT)-Fischer-394-custom. Supplementary table 3. Gene sets enriched in NB patients with high versus low TERT within Tumor Neuroblastoma Gene-TARGET-161. Supplementary table 4: Information on patient samples used in this study.

Neuroblastoma is a deadly pediatric solid tumor with infrequent recurrent somatic mutations. Particularly, the pathophysiology of tumors without MYCN amplification remains poorly defined. Utilizing an unbiased approach, we performed gene set enrichment analysis of RNA-sequencing data from 498 patients with neuroblastoma and revealed a differentially overexpressed gene signature in MYCN nonamplified neuroblastomas with telomerase reverse transcriptase (TERT) gene overexpression and coordinated activation of oncogenic signaling pathways, including E2Fs, Wnt, Myc, and the DNA repair pathway. Promoter rearrangement of the TERT gene juxtaposes the coding sequence to strong enhancer elements, leading to TERT overexpression and poor prognosis in neuroblastoma, but TERT-associated oncogenic signaling remains unclear. ChIP-seq analysis of the human CLB-GA neuroblastoma cells harboring TERT rearrangement uncovered genome-wide chromatin co-occupancy of Brd4 and H3K27Ac and robust enrichment of H3K36me3 in TERT and multiple TERT-associated genes. Brd4 and cyclin-dependent kinases (CDK) had critical regulatory roles in the expression and chromatin activation of TERT and multiple TERT-associated genes. Epigenetically targeting Brd4 or CDKs with their respective inhibitors suppressed the expression of TERT and multiple TERT-associated genes in neuroblastoma with TERT overexpression or MYCN amplification. ChIP-seq and ChIP-qPCR provided evidence that the CDK inhibitor directly inhibited Brd4 recruitment to activate chromatin globally. Therefore, inhibiting Brd4 and CDK concurrently with AZD5153 and dinaciclib would be most effective in tumor growth suppression, which we demonstrated in neuroblastoma cell lines, primary human cells, and xenografts. In summary, we describe a unique mechanism in neuroblastoma with TERT overexpression and an epigenetically targeted novel therapeutic strategy. Significance: Epigenetically cotargeting Brd4 and Cdks suppresses human neuroblastoma with TERT overexpression by inhibiting the TERT-associated gene expression networks.

Despite the rapid growth of academic hospital medicine, scholarly productivity remains poorly characterized. In this cross-sectional study, distribution of academic rank and scholarly output of academic hospital medicine faculty are described. We extracted data for 1,554 hospitalists on faculty at the top 25 internal medicine residency programs. Only 11.7% of faculty had reached associate (9.0%) or full professor (2.7%). The median number of publications was 0.0 (interquartile range [IQR], 0.0-4.0), with 51.4% without a single publication. Faculty 6 to 10 years post residency had a median of 1.0 (IQR, 0.0-4.0) publication, with 46.8% of these faculty without a publication. Among men, 54.3% had published at least one manuscript, compared to 42.7% of women (P < .0001). Predictors of promotion included H-index, number of years post residency graduation, completion of chief residency, and graduation from a top 25 medical school. Promotion remains uncommon in academic hospital medicine, which may be partially due to low rates of scholarly productivity.

This cross-sectional study assesses Medicare Part D and Medicaid spending on extended-release drug formulations and the potential savings associated with switching to generic immediate-release drug formulations., Key Points Question How much do Medicare and Medicaid spend on extended-release drug formulations, and what would be the potential savings associated with switching to immediate-release formulations? Findings In this cross-sectional study of 20 extended-release drugs, Medicare Part D and Medicaid spent a combined $3.1 billion in 2017. Switching to immediate-release drug formulations was associated with an estimated $2.6 billion reduction in spending in 2017 and a $13.7 billion reduction from 2012 to 2017. Meaning The findings suggest that substitution of therapeutically equivalent extended-release drug formulations with immediate-release formulations represents a possible option to reduce Medicare and Medicaid spending., Importance The United States spends more money on medications than any other country. Most extended-release drugs have not consistently shown therapeutic or adherence superiority, and switching these medications to less expensive, generic, immediate-release formulations may offer an opportunity to reduce health care spending. Objective To evaluate Medicare Part D and Medicaid spending on extended-release drug formulations and the potential savings associated with switching to generic immediate-release formulations. Design, Setting, and Participants This cross-sectional study used the 2012 to 2017 Medicare Part D Drug Event and Medicaid Spending and Utilization data sets to analyze 20 extended-release drugs with 37 Medicare formulations and 36 Medicaid formulations. Only cardiovascular, diabetes, neurologic, and psychiatric extended-release drugs saving at most 1 additional daily dose compared with their immediate-release counterparts were included. Extended-release drugs with therapeutic superiority were excluded. Analyses were conducted from January to December 2019. Main Outcomes and Measures Estimated Medicare Part D and Medicaid savings from switching extended-release to immediate-release drug formulations between 2012 and 2017. Results Of the 6252 drugs screened for eligibility from the 2017 Medicaid Drug Utilization database and the 2017 Medicare Part D database, 67 drugs with extended-release formulations that were identified in the Medicare data set (20 distinct drugs with 37 formulations [19 brand, 18 generic]) were included in the analysis. In 2017, Medicare Part D spent $2.2 billion and Medicaid spent $952 million (a combined $3.1 billion) on 20 extended-release drugs. Between 2012 and 2017, Medicare Part D and Medicaid spent $12 billion and $5.9 billion, respectively, on extended-release formulations. Switching from brand-name to generic extended-release formulations was estimated to be associated with a $247 million reduction in Medicare spending and $299 million reduction in Medicaid spending in 2017, whereas switching all brand-name and generic extended-release formulations to immediate-release formulations in both Medicare and Medicaid was estimated to reduce spending by $2.6 billion ($1.8 billion for Medicare and $836 million for Medicaid) in 2017. During the study period, the estimated spending reduction associated with switching all patients receiving extended-release formulations (brand name extended-release and generic extended-release) to generic immediate-release formulations was $13.7 billion ($8.5 billion from Medicare and $5.2 billion from Medicaid). Conclusions and Relevance The findings suggest that switching from extended-release drug formulations to therapeutically equivalent immediate-release formulations when available represents a potential option to reduce Medicare and Medicaid spending.

Simple Summary To investigate whether pediatric and adult chronic myeloid leukemia (CML) have unique molecular characteristics, we studied the transcriptomic signature of pediatric and adult CML cells using high-throughput RNA sequencing. We identified differentially expressed genes and pathways unique to pediatric CML cells compared to adult CML cells. The Rho pathway was significantly dysregulated in pediatric CML cells compared to adult CML cells, suggesting the potential importance in the pathogenesis of pediatric CML. Our study is the first to compare transcriptome profiles of CML across different age groups. A better understanding of the biology of CML across different ages may inform future treatment approaches. Abstract Children with chronic myeloid leukemia (CML) tend to present with higher white blood counts and larger spleens than adults with CML, suggesting that the biology of pediatric and adult CML may differ. To investigate whether pediatric and adult CML have unique molecular characteristics, we studied the transcriptomic signature of pediatric and adult CML CD34+ cells and healthy pediatric and adult CD34+ control cells. Using high-throughput RNA sequencing, we found 567 genes (207 up- and 360 downregulated) differentially expressed in pediatric CML CD34+ cells compared to pediatric healthy CD34+ cells. Directly comparing pediatric and adult CML CD34+ cells, 398 genes (258 up- and 140 downregulated), including many in the Rho pathway, were differentially expressed in pediatric CML CD34+ cells. Using RT-qPCR to verify differentially expressed genes, VAV2 and ARHGAP27 were significantly upregulated in adult CML CD34+ cells compared to pediatric CML CD34+ cells. NCF1, CYBB, and S100A8 were upregulated in adult CML CD34+ cells but not in pediatric CML CD34+ cells, compared to healthy controls. In contrast, DLC1 was significantly upregulated in pediatric CML CD34+ cells but not in adult CML CD34+ cells, compared to healthy controls. These results demonstrate unique molecular characteristics of pediatric CML, such as dysregulation of the Rho pathway, which may contribute to clinical differences between pediatric and adult patients.

Chronic myeloid leukemia (CML) accounts for 2-9% of leukemias in children and adolescents, and occurs with much greater frequency in adults. Compared to adults, children with CML tend to present with higher white blood cell counts and larger spleens, suggesting that the biology of pediatric CML is different from adult CML. We hypothesize that the differences in clinical presentation of pediatric CML are due to unique molecular characteristics that differ from adult CML. To test this hypothesis, we compared the transcriptomic signature of pediatric and adult CML CD34+ cells and healthy age-matched CD34+ cells. CD34+ cells were isolated by FACS from pediatric CML (n=9), adult CML (n=10), pediatric healthy (n=10), and adult healthy (n=10) bone marrow samples. Prepared libraries were sequenced on the Illumina HiSeq 4000 instrument. Raw sequences were trimmed and aligned to the hg38 reference genome with STAR/2.5.1b aligner. Gene level counts were determined with STAR -quantMode option using gene annotations from GENCODE (p5). Differential gene expression and pathway analysis were conducted with R/3.5.3. Counts were normalized with trimmed mean of M-values from the EdgeR/ 3.24.3 package and further transformed with VOOM from the Limma/ 3.38.3 package. A linear model using the empirical Bayes analysis pipeline also from Limma was then used to obtain p-values, adjusted p-values and log-fold changes. Four comparisons were performed: (1) pediatric CML vs pediatric healthy, (2) adult CML vs adult healthy, (3) pediatric CML vs adult CML, and (4) pediatric healthy vs adult healthy. A False Discovery Rate of ≤ .05 and absolute log2 fold-change > 1 was used to define differentially expressed genes (DEGs) in each comparison. To identify potentially unique pathways based on DEG, pathway over-representation was calculated with either goana from the limma package or clueGO. At diagnosis, pediatric patients had higher platelet counts (p=0.001) and larger spleen sizes (p=0.010) than adult patients. Median WBC counts were 273,000 and 143,000 in pediatric and adult patients respectively. A total of 1352 genes were differentially expressed in either adult or pediatric CML CD34+ cells compared to healthy CD34+ cells, 174 of which were expressed similarly in pediatric and adult CML CD34+ cells (54 up- and 120 down-regulated). There were 746 differentially expressed genes (325 up- and 421 down-regulated) in adult CML CD34+ cells compared to adult healthy CD34+ cells, and 432 differentially expressed genes (156 up- and 276 down-regulated) in pediatric CML CD34+ cells compared to pediatric healthy CD34+ cells. In direct comparison of pediatric and adult CML CD34+ cells, 446 genes (270 up and 176 down) were dysregulated in pediatric CML CD34+ cells. Pathway analysis showed that Rho signaling pathway was downregulated in pediatric CML CD34+ cells and several genes in Rho pathway were uniquely dysregulated. ARHGAP27 and VAV2 were significantly upregulated in adult CML CD34+ cells by 3.7-fold (p=0.0453) and 11-fold (p=0.0072), respectively, compared to pediatric CML CD34+ cells. In addition, several genes involved in the NADPH oxidase pathway, one of the best-characterized Rho GTPase-regulated systems, were differently expressed in CML. NCF1, CYBB, and S100A8 were significantly upregulated in adult CML CD34+ cells by 4-fold (p=0.0045), 3.26-fold (p These results demonstrate unique molecular characteristics of pediatric CML that may contribute to the clinical differences at presentation between adult and pediatric disease. A better understanding of the molecular biology of CML across the ages will provide new insights into the pathogenesis of pediatric CML and potentially inform future treatment decisions. Disclosures Davis: Jazz Pharmaceuticals: Research Funding; Novartis Pharmaceuticals: Honoraria. Hijiya: Novartis: Consultancy; Stemline Therapeutics: Consultancy.

Introduction Pediatric chronic myeloid leukemia (CML) accounts for 10-15% of pediatric myeloid leukemias and 2-9% of all pediatric leukemias. There are several unique characteristics of CML diagnosed in children, adolescents, and young adults, compared to adults. They present with higher white blood counts and larger spleens, suggesting that the biology of pediatric CML is different from adult CML. We hypothesize that the differences in clinical presentation of pediatric CML patients are due to unique molecular characteristics that differ from adult CML patients. To test this hypothesis, we studied the transcriptomic signature of pediatric CD34+ CML cells compared to adult CML and normal age-matched bone marrow CD34+ cells. Methods CD34+ cells were isolated by FACS from pediatric CML (n=9), adult CML (n=10), pediatric normal (n=10) and adult normal (n=10) bone marrow samples. Total RNA was isolated from cells, and cDNA libraries were generated. Prepared libraries were sequenced on the Illumina HiSeq 4000 instrument. Raw sequences were trimmed and aligned to the hg38 reference genome with STAR/2.5.1b aligner. Gene level counts were determined with STAR -quantMode option using gene annotations from GENCODE (p5). Differential gene expression and pathway analysis were conducted with R/3.5.3. Counts were normalized with trimmed mean of M-values (TMM) from the EdgeR/ 3.24.3 package and further transformed with VOOM from the Limma/ 3.38.3 package. A linear model using the empirical Bayes analysis pipeline also from Limma was then used to obtain p-values, adjusted p-values and log-fold changes (LogFC). We performed three comparisons: (1) Pediatric CML vs Normal, (2) Adult CML vs Normal, and (3) Pediatric CML vs Adult CML. A False Discovery Rate (FDR) of £ .05 and absolute log2 fold-change > 1 was used to define differentially expressed genes in each comparison. Over-representation analysis was used to identify potentially unique pathways based on differentially expressed genes. Clinical and demographic features at diagnosis were extracted for pediatric and adult CML patients and compared using Fisher's exact test (categorical variables) or Wilcoxon rank sum test (continuous variables). Results Pediatric patients were diagnosed with CML at a median of 11 years (interquartile range (IQR): 10-14) compared to 54 years (IQR: 33-62) for adult patients. At diagnosis, pediatric patients had higher platelet counts (p=0.001) and larger spleen sizes (p=0.010) than adult patients, whereas the white blood cell count and phase at diagnosis did not differ. We found 606 genes (210 up- and 396 down-regulated) differentially expressed in pediatric CML CD34+ cells compared to pediatric normal controls. Interestingly, transcriptional regulators involved in blood cell differentiation including GATA1, TAL1, and KLF1 were differentially enriched in pediatric CML. In comparing adult CML patients to normal adult CD34+ cells, we found 920 genes (379 up- and 541 down-regulated) differentially expressed. Among all dysregulated genes we identified (1352 genes), 174 genes (54 up- and 120-down-regulated) overlapped when comparing pediatric and adult CML patients. Significantly enriched pathways in both adult and pediatric CML cells included PI3K/AKT signaling, MAPK signaling, and Notch/Wnt signaling, which have been previously reported. We found 437 unique genes that were dysregulated only in pediatric CML (270 up- and 167 down-regulated). Notch/Wnt signaling and Rho signaling pathways were significantly enriched. DLC1, a tumor suppressor gene that encodes a RhoGTPase-activating protein, has been known to be downregulated in solid tumors and hematologic malignancies. Interestingly, our data showed that DLC1 is significantly upregulated by 3-fold (p=0.0238) in pediatric CML, but not adult CML CD34+ cells. In addition, we observed that ABR, an inducer of C/EBPa that encodes an activator of RhoGEF and GTPase, was significantly downregulated by 2-fold (p=0.0119) in pediatric but not in adult CML CD34+ cells. Conclusion These results demonstrate unique molecular characteristics of pediatric CML that may contribute to the clinical differences at presentation between adult and pediatric disease. A better understanding of the particular biology of pediatric CML might impact the treatment of those patients in the future. Disclosures Gotlib: Deciphera: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: co-chair of the Study Steering Committee and Research Funding; Blueprint Medicines Corporation: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Chair of the Response Adjudication Committee and Research Funding, Research Funding.

The 90 kDa Ribosomal S6 Kinase (RSK) drives cell proliferation and survival in cancers, although its oncogenic mechanism has not been well characterized. Phosphorylated level of RSK (T573) was increased in acute myeloid leukemia (AML) patients and associated with poor survival. To examine the role of RSK in AML, we analyzed apoptosis and the cell cycle profile following treatment with BI-D1870, a potent inhibitor of RSK. BI-D1870 treatment increased the G2/M population and induced apoptosis in AML cell lines and patient AML cells. Characterization of mitotic phases showed that the metaphase/anaphase transition was significantly inhibited by BI-D1870. BI-D1870 treatment impeded the association of activator CDC20 with APC/C, but increased binding of inhibitor MAD2 to CDC20, preventing mitotic exit. Moreover, the inactivation of spindle assembly checkpoint or MAD2 knockdown released cells from BI-D1870-induced metaphase arrest. Therefore, we investigated whether BI-D1870 potentiates the anti-leukemic activity of vincristine by targeting mitotic exit. Combination treatment of BI-D1870 and vincristine synergistically increased mitotic arrest and apoptosis in acute leukemia cells. These data show that BI-D1870 induces apoptosis of AML cells alone and in combination with vincristine through blocking mitotic exit, providing a novel approach to overcoming vincristine resistance in AML cells.

Introduction Pediatric chronic myeloid leukemia (CML) accounts for 10 to 15% of children with myeloid leukemia and 2 to 9% of all pediatric leukemias. Prior to the discovery of tyrosine kinase inhibitors (TKI) such as imatinib, stem cell transplantation was the only curative treatment for both adults and children with CML. However, due to the small numbers of patients, standardized treatment approaches for pediatric CML have not been established. There are several unique characteristics of CML diagnosed in children and adolescents, and young adults (AYA; 16-29 years), compared to adults. Children and AYA with CML present with a higher white blood count and have larger spleens, higher peripheral blast counts, and lower hemoglobin levels, suggesting that the biology of pediatric CML is different than adult CML. In addition, potential side effects of TKIs unique to pediatric CML patients include impaired bone growth, fertility and immune function, however none have been extensively studied. We hypothesize that the differences in clinical presentation of pediatric CML patients are due to unique molecular characteristics that are absent in adult CML patients. To test this hypothesis, we studied the transcriptomic signature of pediatric CD34+ CML cells compared to adult CML and normal age-matched bone marrow CD34+ cells. Methods CD34+ cells were isolated from pediatric CML (n=7), adult CML (n=8), pediatric normal (n=2) and adult normal (n=3) bone marrow samples. Total RNA was isolated from cells, and then cDNA libraries were generated. Prepared libraries were sequenced on the Illumina HiSeq 4000 instrument. We aligned reads using the HISAT2 alignment software, and mapped to genes with HT-Seq. We removed genes that had zero reads across all the samples, resulting in a set of 4,696 genes that were detected in one or more samples. In case of technical replicates, we used mean of replicates. We performed three differential expression comparisons with edgeR: (1) Pediatric CML vs Adult CML, (2) Adult CML vs Adult Normal, and (3) Pediatric CML vs Pediatric Normal. We used a False Discovery Rate (FDR) of £ 20% and absolute log2 fold-change ³ 1 for selecting differentially expressed genes in each comparison. We used Fisher's exact test to identify significant KEGG pathways for the differentially expressed genes in each comparison. Results Pediatric CML vs Adult CML We found 24 differentially expressed genes (15 over- and 9 under-expressed). Though no pathway was found to be significant at the false discovery rate (FDR) £ 20%, we identified a number of sub-pathways that are relevant. For example, the Chemokine Signaling pathway shows at the top of the list (ordered by raw p-value) because of two genes, XCR1 and HCK, associated with VEGF and MAPK pathways involved in cell proliferation, angiogenesis, DNA repair, and cancer pathogenesis. Adult CML vs Adult Normal We found 60 genes (30 over- and 30 under-expressed) differentially expressed when comparing adult CML patients to normal adults. Ten genes overlapped with 24 genes we identified when comparing pediatric and adult CML patients. We found 11 pathways as significant at FDR £ 10%. Multiple pathways, including Cell adhesion, allograft rejection, Graft versus Host Disease, and Type I diabetes pathways, showed downregulation of MHC, with subsequent downstream reduction in expression of apoptosis-related genes. The IL-17 pathway makes sense, as MAPK, well-known to be associated with various cancers, is down-regulated. Lastly, in the NK pathway the gene DAP12 is up-regulated. This gene is known as a tyrosine kinase binding protein, and although tyrosine kinase inhibitors are the standard treatment for CML, the role of DAP12 in relation to leukemia has not yet been described. Pediatric CML vs Pediatric Normal We found 509 genes (350 over- and 159 under-expressed) differentially expressed in pediatric CML patients compared to normal. Interestingly, transcriptional regulators are differentially enriched in the hematopoietic stem cell differentiation function group including GATA1, GATA2, KLF1 and KLF2. RFC is down-regulated. RFC is a mismatch repair gene known to be involved in colorectal cancer. Many of the significant pathways are involved in glucose and fatty acid metabolism. Our pilot study identified novel molecular features of pediatric CML bone marrow stem cells, providing new insights into the novel biomarkers and pathogenesis of pediatric CML. Disclosures Gotlib: Blueprint Medicines: Consultancy, Honoraria, Research Funding; Promedior: Research Funding; Deciphera: Consultancy, Honoraria, Research Funding; Incyte: Consultancy, Honoraria, Research Funding; Kartos: Consultancy; Celgene: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Research Funding; Novartis: Consultancy, Honoraria, Research Funding.