Citations

Abstract The presence of FMS-like receptor tyrosine kinase-3 internal tandem duplication (FLT3-ITD) mutations in patients with acute myeloid leukemia (AML) is associated with poor clinical outcome. FLT3 tyrosine kinase inhibitors (TKIs), although effective in kinase ablation, do not eliminate primitive FLT3-ITD+ leukemia cells, which are potential sources of relapse. Thus, understanding the mechanisms underlying FLT3-ITD+ AML cell persistence is essential to devise future AML therapies. Here, we show that expression of protein arginine methyltransferase 1 (PRMT1), the primary type I arginine methyltransferase, is increased significantly in AML cells relative to normal hematopoietic cells. Genome-wide analysis, coimmunoprecipitation assay, and PRMT1-knockout mouse studies indicate that PRMT1 preferentially cooperates with FLT3-ITD, contributing to AML maintenance. Genetic or pharmacological inhibition of PRMT1 markedly blocked FLT3-ITD+ AML cell maintenance. Mechanistically, PRMT1 catalyzed FLT3-ITD protein methylation at arginine 972/973, and PRMT1 promoted leukemia cell growth in an FLT3 methylation–dependent manner. Moreover, the effects of FLT3-ITD methylation in AML cells were partially due to cross talk with FLT3-ITD phosphorylation at tyrosine 969. Importantly, FLT3 methylation persisted in FLT3-ITD+ AML cells following kinase inhibition, indicating that methylation occurs independently of kinase activity. Finally, in patient-derived xenograft and murine AML models, combined administration of AC220 with a type I PRMT inhibitor (MS023) enhanced elimination of FLT3-ITD+ AML cells relative to AC220 treatment alone. Our study demonstrates that PRMT1-mediated FLT3 methylation promotes AML maintenance and suggests that combining PRMT1 inhibition with FLT3 TKI treatment could be a promising approach to eliminate FLT3-ITD+ AML cells.

Abstract Context SDHB mutations are found in an increasing number of neoplasms, most notably in paragangliomas and pheochromocytomas (PPGLs). SDHB-PPGLs are slow-growing tumors, but ∼50% of them may develop metastasis. The molecular basis of metastasis in these tumors is a long-standing and unresolved problem. Thus, a better understanding of the biology of metastasis is needed. Objective This study aimed to identify gene methylation changes relevant for metastatic SDHB-PPGLs. Design We performed genome-wide profiling of DNA methylation in diverse clinical and genetic PPGL subtypes, and validated protocadherin γ-C3 (PCDHGC3) gene promoter methylation in metastatic SDHB-PPGLs. Results We define an epigenetic landscape specific for metastatic SDHB-PPGLs. DNA methylation levels were found significantly higher in metastatic SDHB-PPGLs than in SDHB-PPGLs without metastases. One such change included long-range de novo methylation of the PCDHA, PCDHB, and PCDHG gene clusters. High levels of PCDHGC3 promoter methylation were validated in primary metastatic SDHB-PPGLs, it was found amplified in the corresponding metastases, and it was significantly correlated with PCDHGC3 reduced expression. Interestingly, this epigenetic alteration could be detected in primary tumors that developed metastasis several years later. We also show that PCDHGC3 down regulation engages metastasis-initiating capabilities by promoting cell proliferation, migration, and invasion. Conclusions Our data provide a map of the DNA methylome episignature specific to an SDHB-mutated cancer and establish PCDHGC3 as a putative suppressor gene and a potential biomarker to identify patients with SDHB-mutated cancer at high risk of metastasis who might benefit from future targeted therapies.

Background:Multiple myeloma (MM) is a heterogeneous disease with varying survival outcomes depending on the presence of certain genetic abnormalities. Common abnormalities include trisomies, translocations involving the chromosome 14, and amplifications or deletions of chromosomes 1, 13, and 17. t(11;14), occurring in 15% of patients with myeloma, had been considered a standard risk abnormality, but recent data suggest inferior outcome. This is important as new therapeutic options such as the BCL‐2 inhibitor venetoclax has been shown to be particularly effective in t(11;14) patients.Aims: Primary objective: To describe the overall survival of myeloma patients with translocation t(11:14) Secondary objectives: To determine the response rates, progression free survival, time to progression, time to next treatment, duration of responses and overall survival with different regimens among patients with t(11;14), to determine the prognostic factors for overall survival among patients with t(11;14), and to identify the spectrum of co‐existing genetic abnormalities among patients with t(11;14)Methods:This was a multicenter study to identify the outcomes of patients with t(11;14), using a retrospectively assembled cohort. Patients with MM diagnosed between 2005 and 2015 with t(11;14) identified on FISH performed within six months of diagnosis, and with treatment details available and if alive, a minimum of 12 months of follow up, were enrolled.Results:The current analysis includes 848 patients; median age of 64.4 years; 60.0% male. The median follow‐up from diagnosis for the entire cohort was 46.5 months; 86.7% of the patients were alive at the last follow up. ISS stage distribution included: Stage I (35.3%), Stage II (38.9%) and Stage III (25.8%). The distribution of FISH abnormalities included: del 13q (14.5%), 1q amp (12.1%), del 17p or monosomy 17 (6.1%). Initial therapy included different regimens: 23.3% had an IMiD, 43.3% had a PI, 20.0% had both and 13.3% had no novel agent. The drug classes by line of therapy are shown in Table 1. A stem cell transplant (SCT), defined as within 12 months of start of first line treatment, was used in 39.1% of patients. The median time to next treatment (TTNT) after initial treatment was 13.7 (95% CI: 11.3 to 16.5) months. The median overall survival (OS) from diagnosis for the entire cohort was 82.5 (95% CI: 73.5 to 95.8) months; 4‐year estimates for those diagnosed from January 2005 to December 2009, and from January 2010 to December 2014 were 75.1% and 70.2%, respectively. Median OS by initial regimen is shown in Figure 1; those receiving an early SCT had median OS of 116.9 (95% CI: 85.6 to NA) months.Summary/Conclusion:This is the first study to examine the outcomes of a large group of myeloma patients with t(11;14) abnormality. Patients receiving a combination of a PI and an IMiD appear to have the best survival outcomes. Patients receiving an early SCT appear to have excellent survival with median OS approaching 10 years. Additional patients are being accrued to this study and additional analysis examining the variables affecting response duration and survival will be presented.image

Abstract Patients with primary immunodeficiencies undergoing allogeneic hematopoietic cell transplantation (HCT) for difficult-to-control infections can experience immune reconstitution inflammatory syndrome (IRIS) following engraftment. In 3 patients with post-HCT IRIS related to mycobacterial infection, in vitro data demonstrate the emergence of pathogen-specific immune responses and a concomitant rise in plasma inflammatory markers.

Objective This study aimed to evaluate a deep learning protocol to identify neoplasia in intraductal papillary mucinous neoplasia (IPMN) in comparison to current radiographic criteria. Methods A computer-aided framework was designed using convolutional neural networks to classify IPMN. The protocol was applied to magnetic resonance images of the pancreas. Features of IPMN were classified according to American Gastroenterology Association guidelines, Fukuoka guidelines, and the new deep learning protocol. Sensitivity and specificity were calculated using surgically resected cystic lesions or healthy controls. Results Of 139 cases, 58 (42%) were male; mean (standard deviation) age was 65.3 (11.9) years. Twenty-two percent had normal pancreas; 34%, low-grade dysplasia; 14%, high-grade dysplasia; and 29%, adenocarcinoma. The deep learning protocol sensitivity and specificity to detect dysplasia were 92% and 52%, respectively. Sensitivity and specificity to identify high-grade dysplasia or cancer were 75% and 78%, respectively. Diagnostic performance was similar to radiologic criteria. Areas under the receiver operating curves (95% confidence interval) were 0.76 (0.70–0.84) for American Gastroenterology Association, 0.77 (0.70–0.85) for Fukuoka, and 0.78 (0.71–0.85) for the deep learning protocol ( P = 0.90). Conclusions The deep learning protocol showed accuracy comparable to current radiographic criteria. Computer-aided frameworks could be implemented as aids for radiologists to identify high-risk IPMN.

Innate immune sensing is essential for the proinflammatory program in cellular senescence.

Background Mutations in genes encoding ion channels or sarcomeric proteins are an important cause of hereditary cardiac disease. However, the severity of the resultant disease varies considerably even among those with an identical mutation. Such clinical variation is often thought to be explained largely by differences in genetic background or ‘modifier genes’. We aimed to test the prediction that identical genetic backgrounds result in largely similar clinical expression of a cardiac disease causing mutation, by studying the clinical expression of mutations causing cardiac disease in monozygotic twins. Methods We compared first available clinical information on 46 monozygotic twin pairs and 59 control pairs that had either a hereditary cardiomyopathy or channelopathy. Results Despite limited power of this study, we found significant heritability for corrected QT interval (QTc) in long QT syndrome (LQTS). We could not detect significant heritability for structural traits, but found a significant environmental effect on thickness of the interventricular septum in hypertrophic cardiomyopathy. Conclusions Our study confirms previously found robust heritability for electrical traits like QTc in LQTS, and adds information on low or lacking heritability for structural traits in heritable cardiomyopathies. This may steer the search for genetic modifiers in heritable cardiac disease.

1065 Background: Triple-negative breast cancer (TNBC) has been shown to display cyclin-dependent kinase 7 (CDK7)-dependent transcriptional addition and is sensitive to a CDK7 inhibitor THZ1. As tumor heterogeneity is well known, we sought to identify predictive markers of sensitivity to CDK7 inhibition in TNBC. Methods: Published mRNA microarray data was analyzed to identify genes associated with sensitivity of TNBC cells to the CDK7 inhibitor THZ1. Cell survival assay after THZ1 treatment was performed using Cell Counting Kit-8. Expression of SOX9 was examined by Western blot in cell lines and IHC in breast cancer tissue microarray. Patient survival analysis was done using the Kaplan-Meier method. Results: Analysis of published mRNA microarray data showed that SOX9 was overexpressed in the MDA-468 and BT-549 TNBC cell lines, which were sensitive to the CDK7 inhibitor THZ1 and showed decreased SOX9 expression with THZ1 treatment. We treated 10 TNBC cell lines with various concentrations of THZ1 and found that these cell lines displayed a wide spectrum of sensitivity to THZ1, with an IC50 ranging from 20-30 nM in sensitive lines (MDA-468 and MDA-231) to ~300 nM in insensitive lines (BT-20 and MDA-157). There was a strong correlation of SOX9 expression by Western blot and sensitivity to THZ1 in these cell lines (Pearson correlation, r = 0.82, P= 0.01). IHC of two tissue microarrays containing 278 breast cancer samples showed that SOX9 expression was significantly higher in TNBC (n = 59) compared to hormone positive breast cancer (n = 173; P< 0.01). Among the 59 TNBC cases, 43 had high SOX9 expression and 16 had low SOX9 expression. Patients with high or low SOX expression had similar grade, T stage and nodal involvement (All P> 0.20). Finally, with standard of care treatment, TNBC patients with high SOX9 expression had a significantly worse overall survival (OS) compared to patients with low SOX9 expression (2 year OS rate 100% vs 92.9%, 5 year OS rate 93.8% vs 83.3%, log rank P= 0.03). Conclusions: SOX9 expression level in TNBC cell lines was associated with sensitivity to the CDK7 inhibitor THZ1. TNBC patients with high expression of SOX9 had worse OS, and may benefit from CDK7 inhibition as a novel therapy.