Citations

Abstract Imatinib mesylate (IM) has revolutionized the treatment of gastrointestinal stromal tumor (GIST). However, most patients inevitably acquire IM resistance. Second- and third-line treatments exhibit modest clinical benefits with a median time to disease progression of 4 to 6 months, highlighting the urgency for novel therapeutic approaches. Here, we report that the expression of BCL6, a known oncogenic driver and transcriptional repressor, was significantly induced in GIST cells following IM treatment. Elevated BCL6 levels suppressed apoptosis and contributed to IM resistance. Mechanistically, BCL6 recruited SIRT1 to the TP53 promoter to modulate histone acetylation and transcriptionally repress TP53 expression. The reduction in p53 subsequently attenuated cell apoptosis and promoted tolerance of GIST cells to IM. Concordantly, treatment of GIST cells showing high BCL6 expression with a BCL6 inhibitor, BI-3802, conferred IM sensitivity. Furthermore, BI-3802 showed striking synergy with IM in IM-responsive and IM-resistant GIST cells in vitro and in vivo. Thus, these findings reveal a role for BCL6 in IM resistance and suggest that a combination of BCL6 inhibitors and IM could be a potentially effective treatment for GIST. Significance: BCL6 drives resistance to imatinib by inhibiting p53-mediated apoptosis and can be targeted in combination with imatinib to synergistically suppress tumor growth, providing a therapeutic strategy for treating gastrointestinal stromal tumor.

Krabbe disease (KD) is a progressive and devasting neurological disorder that leads to the toxic accumulation of psychosine in the white matter of the central nervous system (CNS). The condition is inherited via biallelic, loss-of-function mutations in the galactosylceramidase (GALC) gene. To rescue GALC gene function in the CNS of the twitcher mouse model of KD, an adeno-associated virus serotype 1 vector expressing murine GALC under control of a chicken β-actin promoter (AAV1-GALC) was administered to newborn mice by unilateral intracerebroventricular injection. AAV1-GALC treatment significantly improved body weight gain and survival of the twitcher mice (n = 8) when compared with untreated controls (n = 5). The maximum weight gain after postnatal day 10 was significantly increased from 81% to 217%. The median lifespan was extended from 43 days to 78 days (range: 74–88 days) in the AAV1-GALC-treated group. Widespread expression of GALC protein and alleviation of KD neuropathology were detected in the CNS of the treated mice when examined at the moribund stage. Functionally, elevated levels of psychosine were completely normalized in the forebrain region of the treated mice. In the posterior region, which includes the mid- and the hindbrain, psychosine was reduced by an average of 77% (range: 53–93%) compared to the controls. Notably, psychosine levels in this region were inversely correlated with body weight and lifespan of AAV1-GALC-treated mice, suggesting that the degree of viral transduction of posterior brain regions following ventricular injection determined treatment efficacy on growth and survivability, respectively. Overall, our results suggest that viral vector delivery via the cerebroventricular system can partially correct psychosine accumulation in brain that leads to slower disease progression in KD.

Introduction The prevalence, severity, and quality of life (QoL) impact of diabetic retinopathy (DR) among African–Americans (AAs) with end-stage kidney disease (ESKD) undergoing dialysis are unknown. Research design and methods A cross-sectional study was conducted on 93 AA adults with diabetes and ESKD. The diagnosis of DR was based on a review of medical records and/or a positive photograph with a portable hand-held device reviewed by both artificial intelligence software and a retinal specialist. QoL, physical disability social determinants of health (SDoHs) were assessed by standardized questionnaires. Results The prevalence of DR was 75%, with 33% of participants having mild, 9.6% moderate and 57.4% severe DR. A total of 43% had normal visual acuity; 45% had moderate visual impairment; and 12% had severe visual impairment. We found a high burden of disease, multiple SDoH challenges, and low QoL and general health among patients with ESKD. The presence of DR had no significant impact on physical health and QoL compared with participants without DR. Conclusions DR is present in 75% of AA patients with diabetes and ESKD on haemodialysis. ESKD has a significant burden on general health and QoL; however, DR has a minor additional impact on the overall physical health and QoL in people with ESKD.

AbstractErectile dysfunction (ED) caused by cavernous nerve injury (CNI) is refractory to heal mainly ascribed to the adverse remodeling of the penis induced by ineffectual microvascular perfusion, fibrosis, and neurotrophins scarcity in cavernosum. Phosphodiesterase type V inhibitors (PDE5i) have been regarded as an alternative candidate drug for avoiding penile neuropathy. However, the therapeutic efficacy is severely limited due to poor accumulation under systemic medication and endogenous nitric oxide (NO) deficiency in cavernosum. Herein, an innovative liposomal microbubble (MB) loaded with both Sildenafil (one of PDE5i) and NO was designed. Ultrasound‐targeted MB destruction (UTMD)‐mediated efficient release and integration erectogenic agents into corpus cavernosum with high biosafety. On a bilateral CNI rat model, the multifunctional MB‐cooperated UTMD improved microvascular perfusion in penis, simultaneously, alleviated hypoxia and oxidative stress, indicating successful activation of NO–cyclic guanosine monophosphate pathway. Also, evaluation of the endothelial/muscular composition, intracavernosal pressure, and neural integrity in the penis proved that coordinated intervention reversed the abnormal structural remodeling and promoted the recovery of functional erection. Our work demonstrates that MB loading Sildenafil and NO combined with UTMD hold great promise to “awaken” the efficacy of PDE5i in neurogenic ED, which provided a superior option for ensuring penile rehabilitation.

Purpose The combination of SENSE and spiral imaging with fat/water separation enables high temporal efficiency. However, the corresponding computation increases due to the blurring/deblurring operation across the multi‐channel data. This study presents two alternative models to simplify computational complexity in the original full model (model 1). The performances of the models are evaluated in terms of the computation time and reconstruction error. Methods Two approximated spiral MRI reconstruction models were proposed: the comprehensive blurring before coil operation (model 2) and the regional blurring before coil operation (model 3), respectively, by altering the order of coil‐sensitivity encoding process to distribute signals among the multi‐channel coils. Four subjects were recruited for scanning both fully sampled T 1 ‐ and T 2 ‐weighted brain image data with simulated undersampling for testing the computational efficiency and accuracy on the approximation models. Results Based on the examples, the computation time can be reduced to 31%–47% using model 2, and to 39%–56% using model 3. The quality of the water image remains unchanged among the three models, whereas the primary difference in image quality is in the fat channel. The fat images from model 3 are consistent with those from model 1, but those from model 2 have higher normalized error, differing by up to 4.8%. Conclusion Model 2 provides the fastest computation but exhibits higher error in the fat channel, particularly in the high field and with long acquisition window. Model 3, an abridged alternative, is also faster than the full model and can maintain high accuracy in reconstruction.

AbstractObjectivesAlthough hemispheric surgeries are among the most effective procedures for drug‐resistant epilepsy (DRE) in the pediatric population, there is a large variability in seizure outcomes at the group level. A recently developed HOPS score provides individualized estimation of likelihood of seizure freedom to complement clinical judgement. The objective of this study was to develop a freely accessible online calculator that accurately predicts the probability of seizure freedom for any patient at 1‐, 2‐, and 5‐years post‐hemispherectomy.MethodsRetrospective data of all pediatric patients with DRE and seizure outcome data from the original Hemispherectomy Outcome Prediction Scale (HOPS) study were included. The primary outcome of interest was time‐to‐seizure recurrence. A multivariate Cox proportional‐hazards regression model was developed to predict the likelihood of post‐hemispheric surgery seizure freedom at three time points (1‐, 2‐ and 5‐ years) based on a combination of variables identified by clinical judgment and inferential statistics predictive of the primary outcome. The final model from this study was encoded in a publicly accessible online calculator on the International Network for Epilepsy Surgery and Treatment (iNEST) website (https://hops‐calculator.com/).ResultsThe selected variables for inclusion in the final model included the five original HOPS variables (age at seizure onset, etiologic substrate, seizure semiology, prior non‐hemispheric resective surgery, and contralateral fluorodeoxyglucose–positron emission tomography [FDG‐PET] hypometabolism) and three additional variables (age at surgery, history of infantile spasms, and magnetic resonance imaging [MRI] lesion). Predictors of shorter time‐to‐seizure recurrence included younger age at seizure onset, prior resective surgery, generalized seizure semiology, FDG‐PET hypometabolism contralateral to the side of surgery, contralateral MRI lesion, non‐lesional MRI, non‐stroke etiologies, and a history of infantile spasms. The area under the curve (AUC) of the final model was 73.0%.SignificanceOnline calculators are useful, cost‐free tools that can assist physicians in risk estimation and inform joint decision‐making processes with patients and families, potentially leading to greater satisfaction. Although the HOPS data was validated in the original analysis, the authors encourage external validation of this new calculator.

Abstract Medulloblastoma (MB) is a highly malignant childhood brain tumor comprising a collection of molecularly and clinically distinct entities. Mutations in chromatin-modifying genes distribute across subgroups and account for nearly half of all MBs. However, the molecular consequences of chromatin modifier alterations remain poorly understood. Herein, we characterize the chromatin landscape of fifty-two primary MBs representing each MB subgroup using chromatin immunoprecipitation followed by sequencing (ChIP-seq) for six histone marks and perform multi-layered integration with somatic genetics, genome-wide DNA methylation, and transcriptomic datasets extracted from the same tumors. Analysis of differential chromatin states across MB subgroups identified significant enrichment of a bivalent enhancer state (EnhBiv) in Group 4 MB. Group 4-specific EnhBivs mapped to promoters of key neurodevelopmental genes and transcription factors and was associated with increased DNA methylation and reduced expression. In accordance with higher EnhBivs coverage in Group 4 MB, we found that KDM2B, a H3K4me3 and H3K36me2 demethylase, is highly expressed in Group 4 MBs and patient-derived xenografts (PDXs). KDM2B knockout mediated by CRISPR targeting suppressed growth of both Group 3 MB cell lines in vitro and Group 4 MB PDXs in vivo but had no effect on control SHH-MB cells, suggesting that KDM2B is a novel selective dependency in MB. Knockout of KDM2B in MB cells induced profound upregulation of PRC2 targets, genes regulated by bivalent histone marks, as well as genes involved in neuronal differentiation. Further biochemical and molecular studies demonstrated that KDM2B interacts with PRC2 complex subunits and occupies gene promoters associated with Group 4-specific EnhBiv chromatin. In summary, our comprehensive characterization of the MB chromatin landscape in a large cohort of primary tumors provides novel insights into the epigenetic basis of MB and implicates KDM2B as a novel Group 4 MB dependency that should be prioritized as a therapeutic target in this subgroup.

e14594 Background: Voyager-V1 (VV1) is an oncolytic vesicular stomatitis virus engineered to express interferon beta (IFNβ) to boost cellular antitumor immunity and sodium iodine symporter (NIS). A phase 1 trial investigating a single infusion of VV1 in patients with relapsed refractory multiple myeloma and T-cell lymphoma (TCL) showed promising and durable clinical activity, primarily in patients with TCL. VV1 infects tumor cells and macrophages in the lymph nodes and spleen, resulting in release of tumor antigens and IFNβ that activates and boost cellular antitumor immunity. We present the preliminary pharmacokinetic analysis in patients given one intravenous (IV) dose of VV1. Methods: Patients received 5e9 to 1.7e11 TCID50 (50% tissue culture infective dose) of VV1 given over 30 minutes. We also explored the impact of infusion duration (0.25, 0.5,1 and 3 hours) in 17 patients with solid tumors. The objectives were to determine the impact of viral dose on pharmacokinetics (PK) of VSV and IFNβ. For VSV and IFNβ PK, whole blood was collected in 30 patients on days 1, 2, 3, and 8. Dose levels were 1.7E10, 5E10, and 1.7E11 TCID50. The plasma concentration-time data were estimated with non-compartmental analysis using WinNonlin 8.3. Results: The half-life of VV1 is comparable (10-12h) between dose levels of 1.7e10, 5e10 and 1.7e11. Ideal infusion rate was found to be 30 minutes and provides the highest Cmax and AUC. Most peak concentrations for viremia and IFNβ were achieved between ‘end of infusion’ and 2.5 hours, 4.5 and 24 hours, respectively. Following infusion, a second concentration peak is found in over half the patients leading to highly variable terminal elimination half-life, specifically where the second peak is at 24 hours. There was no second peak for IFNβ levels. Peak plasma concentration and systemic exposure increased in proportion to increased dose, consistent with linear clearance. Conclusions: The 30 minute infusion rate was considered the best as its PK provides the highest Cmax and AUC with no significant CRS differences among other groups. IL-6 and IFNα markers at hour 4 indicate a likely CRS and hour 24 provides a possible prediction of the grade. Cmax and AUC were also highest at 1.7e11 TCID50. This is the recommended dose that will be used in the expansion arm in patients with TCL. Clinical trial information: NCT03017820 , NCT02923466 . [Table: see text]

7530 Background: Oncolytic virotherapy is a novel immunomodulatory therapeutic approach currently under study for relapsed refractory (R/R) hematologic malignancies. The engineered Vesicular Stomatitis Virus VSV-IFNβ-NIS used in this study encodes interferon beta (IFNβ) and sodium iodine symporter (NIS). Virally-encoded IFNβ serves as an index of viral proliferation and enhances host anti-tumor immunity. Herein, we report the updated results of the phase 1 clinical trial NCT03017820 of a one-time administration of systemic VSV-IFNβ-NIS among patients (pts) with R/R multiple myeloma (MM), T cell Lymphoma (TCL) and Acute myeloid Leukemia (AML) with particular focus on the TCL cohort treated at the highest dose level (DL4) without Ruxolitinib. Methods: VSV-IFNβ-NIS was administered as a single IV dose following a classical 3+3 phase I trial, starting at 5e9 TCID50 DL1 through 1.7e11 TCID50 DL4. A dose expansion cohort of 8 additional R/R TCL pts was added at DL4 in view of an initial signal of activity. The primary objective was to determine the maximum tolerated dose of VSV-IFNβ-NIS as a single agent. Secondary objectives were determination of safety profile and preliminary efficacy of VSV-IFNβ-NIS. Adverse events (AEs) are reported based on CTCAE V4; cytokine release syndrome (CRS) grading was based on Lee (Blood 2014) criteria. Results: To date, a total of 43 pts received VSV-IFNβ-NIS: MM (N=21), TCL (N=21) and AML (N=1). In the TCL cohort: at DL4 Group A (no Ruxolitinib), 12 pts were registered, but only 11 pts were treated (mycosis fungoides (MF) N=3; ALK- ALCL N=1; PTCL-NOS N=2; AITL N=4; Nodal PTCL, TFH N=2; ages 33-79). These pts received a median of 3 lines of therapy (range: 1-5). No dose limiting toxicities were observed. Grades 3 and higher AEs were hematologic with transient lymphopenia (63.6%), neutropenia (36.4%) being the most common. The non-hematologic AEs observed included unique toxicities such as CRS grades 1-2 (81.8%); the transient transaminitis grade 1-2 (36.4%) and grade 3 (27.3%) along with thrombocytopenia grade 1-2 (63.6%) and grade 3 (18.2%) were a reflection IFNβ toxicity. All the AEs observed were short lived. Responses were seen in pts with PTCL. At DL4, in pts with systemic PTCL (N=9), there were 5 responses including 3 complete responses (CR) with two long-lasting at 24 months, an ongoing 15 month CR, and a 5 month CR, and 2 partial responses (PR) lasting 5 months in one pts and 6 months in the other. Conclusions: These updated results of single agent VSV-IFNβ-NIS which include pts with PTCL treated at the highest dose level and a dose expansion cohort demonstrates not only the safety of VSV-IFNβ-NIS but also a strong efficacy signal in pts with PTCL with impressive durable responses. Two expansion cohorts at DL4 have been added (20 additional PTCL, 10 B-cell lymphoma pts) to obtain additional data on tolerability and efficacy and biomarkers of response in these pts. Clinical trial information: NCT03017820 .