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Extracellular vesicles (EVs) contribute to a variety of signaling processes and the overall physiological and pathological states of stem cells and tissues. Human induced pluripotent stem cells (hiPSCs) have unique characteristics that can mimic embryonic tissue development. There is growing interest in the use of EVs derived from hiPSCs as therapeutics, biomarkers, and drug delivery vehicles. However, little is known about the characteristics of EVs secreted by hiPSCs and paracrine signaling during tissue morphogenesis and lineage specification. Methods: In this study, the physical and biological properties of EVs isolated from hiPSC-derived neural progenitors (ectoderm), hiPSC-derived cardiac cells (mesoderm), and the undifferentiated hiPSCs (healthy iPSK3 and Alzheimer’s-associated SY-UBH lines) were analyzed. Results: Nanoparticle tracking analysis and electron microscopy results indicate that hiPSC-derived EVs have an average size of 100–250 nm. Immunoblot analyses confirmed the enrichment of exosomal markers Alix, CD63, TSG101, and Hsc70 in the purified EV preparations. MicroRNAs including miR-133, miR-155, miR-221, and miR-34a were differently expressed in the EVs isolated from distinct hiPSC lineages. Treatment of cortical spheroids with hiPSC-EVs in vitro resulted in enhanced cell proliferation (indicated by BrdU+ cells) and axonal growth (indicated by β-tubulin III staining). Furthermore, hiPSC-derived EVs exhibited neural protective abilities in Aβ42 oligomer-treated cultures, enhancing cell viability and reducing oxidative stress. Our results demonstrate that the paracrine signaling provided by tissue context-dependent EVs derived from hiPSCs elicit distinct responses to impact the physiological state of cortical spheroids. Overall, this study advances our understanding of cell‒cell communication in the stem cell microenvironment and provides possible therapeutic options for treating neural degeneration.

AbstractBackgroundEnterococcal cardiovascular implantable electronic device (CIED) infections are not well characterized.MethodsData from the Multicenter Electrophysiologic Device Infection Cohort, a prospective study of CIED infections, were used for descriptive analysis of adults with enterococcal CIED infections.ResultsOf 433 patients, 21 (4.8%) had enterococcal CIED infection. Median age was 71 years. Twelve patients (57%) had permanent pacemakers, five (24%) implantable cardioverter defibrillators, and four (19%) biventricular devices. Median time from last procedure to infection was 570 days. CIED‐related bloodstream infections occurred in three patients (14%) and 18 (86%) had infective endocarditis (IE), 14 (78%) of which were definite by the modified Duke criteria. IE cases were classified as follows: valvular IE, four; lead IE, eight; both valve and lead IE, six. Vegetations were demonstrated by transesophageal echocardiography in 17 patients (81%). Blood cultures were positive in 19/19 patients with confirmed results. The most common antimicrobial regimen was penicillin plus an aminoglycoside (33%). Antibiotics were given for a median of 43 days. Only 14 patients (67%) underwent device removal. There was one death during the index hospitalization with four additional deaths within 6 months (overall mortality 24%). There were no relapses.ConclusionsEnterococci caused 4.8% of CIED infections in our cohort. Based on the late onset after device placement or manipulation, most infections were likely hematogenous in origin. IE was the most common infection syndrome. Only 67% of patients underwent device removal. At 6 months follow‐up, no CIED infection relapses had occurred, but overall mortality was 24%.

Abstract Background Platinum chemotherapy (carboplatin or cisplatin) + etoposide is the current 1L standard of care treatment (tx) for ES-SCLC. Despite high response rates on this regimen, patient (pt) outcomes remain poor. IMpower133 is a Ph1/3, double-blind, randomized, placebo (PBO)-controlled trial that is evaluating the efficacy and safety of adding PD-L1-inhibitor atezo or PBO to 1L tx for ES-SCLC (NCT02763579). Methods IMpower133 enrolled pts without prior tx for ES-SCLC; PD-L1 testing was not required. Pts were randomized 1:1 to four 21-day cycles of carboplatin (AUC 5 mg/mL/min IV, Day 1) + etoposide (100 mg/m2 IV, Days 1-3) with either atezo (1200 mg IV, Day 1) or PBO, then maintenance atezo or PBO until PD, unacceptable toxicity or loss of clinical benefit. Maintenance prophylactic cranial irradiation (PCI) was allowed per protocol, while definitive thoracic radiation (TR) was not. Coprimary endpoints were OS and investigator-assessed PFS. A key exploratory endpoint was outcomes by blood tumor mutation burden (bTMB) analyzed at prespecified cutoffs (≥ 16 vs < 16 and ≥ 10 vs < 10 mutations/Mb). Results Adding atezo to carboplatin + etoposide demonstrated significant improvement in efficacy (OS and PFS) in 1L ES-SCLC (Table). Survival benefits were consistent across key subgroups and prespecified bTMB cutoffs. 44 pts (22 in each arm [per ITT]) received PCI, and 7 (3 in atezo arm, 4 in PBO arm) received TR. Gr 3-4 tx-related adverse events (AEs) occurred in 57% of atezo pts vs 56% of PBO pts; serious tx-related AEs occurred in 23% vs 19%. Occurrence of CNS-related AEs in pts who had PCI are shown in the Table. Conclusion Adding atezo to carboplatin + etoposide resulted in a significant improvement in survival in this 1L ES-SCLC all-comers population. There were no new safety signals, including in pts who received PCI or TR. Atezo + carboplatin + etoposide may represent a new standard regimen for untreated ES-SCLC. Atezo + carboplatin + etoposiden = 201PBO + carboplatin + etoposiden = 202Co-primary endpointsMedian OS, mo12.310.3HR 0.70 (95% CI: 0.54, 0.91); P = 0.0069Median PFS, mo5.24.3HR 0.77 (95% CI: 0.62, 0.96) P = 0.017Secondary efficacy endpointsInvestigator-assessed confirmed ORR, %60.264.4Median DoR, mo4.23.9CNS-related AEs in pts who had PCI, n (%)a,bn = 23n = 21Headache8 (34.8)4 (19.0)Asthenia5 (21.7)2 (9.5)Dizziness2 (8.7)0Insomnia2 (8.7)1 (4.8)Fall2 (8.7)1 (4.8)aSafety population; safety analyses conducted according to tx received (1 pt randomized to the control arm received a dose of atezo).bIncludes AEs occurring in ≥ 2 patients. Citation Format: Aaron S. Mansfield, Stephen V. Liu, Aleksandra Szczęsna, Libor Havel, Maciej Kzrakowski, Maximilian J. Hochmair, Florian Huemer, György Losonczy, Melissa L. Johnson, Makoto Nishio, Martin Reck, Tony S. Mok, Sivuonthanh Lam, David S. Shames, Juan Liu, Fairooz Kabbinavar, Alan Sandler, Leora Horn. IMpower133: Primary efficacy and safety + CNS-related adverse events in a Ph1/3 study of first-line (1L) atezolizumab (atezo) + carboplatin + etoposide in extensive-stage SCLC (ES-SCLC) [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 CT199.

Abstract Background: The fastest growing cause of cancer related death is hepatocellular carcinoma (HCC), in part due to the rising prevalence of nonalcoholic steatohepatitis (NASH). HCC cases are expected to increase during 2015-2030. Cholecystokinin (CCK), blood levels are increased in those consuming high fat diets and CCK receptors have been identified in normal liver, fibroblasts, and immune cells. Hypothesis: We hypothesize that CCK receptor blockade could decrease NASH and prevent HCC in a mouse model.Methods: We examined whether CCK receptor blockade with proglumide could decrease NASH in the choline deficient ethionine supplemented (CDE)-diet mouse model. Two cohorts of Female C57BL/6 mice (N=65) mice were examined: (1) a preventive study in which mice were treated for 12 and 18 weeks to determine if proglumide could prevent NASH and HCC and (2) a ‘reversal study’ in which histologic and biochemical NASH was induced on a 75% CDE high fat diet for 12 weeks followed by treatment with proglumide for 6 weeks (until week 18) while remaining on the CDE diet to determine if CCK-receptor blockade could reverse NASH once established. Control mice received the same high fat diet with choline and half received proglumide therapy. Results: Alanine aminotransferase, aspartate aminotransferases, and bilirubin were increased in mice on the CDE/Regular (untreated water) diet and these values returned to near normal with proglumide therapy in the prevention study and also reversed after NASH was established. Histologic scoring showed significant decreased inflammation, fibrosis and steatosis in mice on the high fat CDE diet when treated with proglumide. 35% of the mice (N=23) at week 18 developed HCC or dysplastic nodules on the CDE diet while none of the mice in the CDE/proglumide prevention (N=15) or reversal therapy groups (N=15) had HCC. Mice on the lard-control diet had fatty livers at week 18 but no evidence of NASH histologically or biochemically and no HCC. Fibrosis was decreased in mice treated with proglumide as evidence by Masson’s trichrome stain and Western blot for FAP. Gene expression of the liver’s collagen-4, TGFβR11, PDGH-Rβ, and collagen-1α1 as determined by qRT-PCR decreased with proglumide treatment. Control diet fed mice had normal serum tests and fibrosis biomarkers. Conclusion: This data supports our novel hypothesis that CCK receptors play a role in NASH-associated HCC. CCK receptor blockade decreased histologic and biochemical evidence of NASH and prevented HCC. Since proglumide has already been tested in human subjects for peptic ulcer disease decades ago and is known to be orally bioavailable, results of our study could easily be translated into a clinical trial in human subjects to improve NASH to prevent HCC. Supported by AGA Research Foundation, Ruesch Foundation, and a grant from NIH, TL1TR001431 Citation Format: Martha D. Gay, Victor Ciofoaia, Sandeep Nadella, Hong Cao, Matthew Huber, Robin D. Tucker, Narayan Shivapurkar, Bhaskar Kallakury, Alexander H. Kroemer, Jill P. Smith. Cholecystokinin receptor antagonist proglumide reverses nonalcoholic steatohepatitis and prevents hepatocellular carcinoma [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 2728.

Abstract In clinical cancer treatment, genomic alterations would often affect the response of patients to anticancer drugs. Studies have shown that molecular features of tumors could be biomarkers predictive of sensitivity or resistance to anticancer agents, but the identification of actionable mutations are often constrained by the incomplete understanding of cancer genomes. Recent progresses of next-generation sequencing technology greatly facilitate the extensive molecular characterization of tumors and promote precision medicine in cancers. More and more clinical studies, cancer cell lines studies, CRISPR screening studies as well as patient-derived model studies were performed to identify potential actionable mutations predictive of drug response, which provide rich resources of molecularly and pharmacologically profiled cancer samples at different levels. Such abundance of data also enables the development of various computational models and algorithms to solve the problem of drug sensitivity prediction, biomarker identification and in silico drug prioritization by the integration of multiomics data. Here, we review the recent development of methods and resources that identifies mutation-dependent effects for cancer treatment in clinical studies, functional genomics studies and computational studies and discuss the remaining gaps and future directions in this area.

Background:Iberdomide (IBER) is a novel cereblon (CRBN) E3 ligase modulatory compound (CELMoD) that is being investigated as monotherapy, in combination with dexamethasone (DEX), and in combination with DEX and daratumumab or bortezomib in a phase 1b/2a dose‐escalation study in relapsed/refractory multiple myeloma (RRMM). IBER modulates CRBN, which induces ubiquitination of Aiolos, Ikaros and ZFP91, increases their proteasome‐dependent degradation, and thereby inhibits myeloma cell growth. IBER binds more potently to CRBN and is more efficient at degrading Aiolos and Ikaros than the immunomodulatory agents (IMiDs) lenalidomide (LEN) and pomalidomide (POM) and it can overcome IMiD drug resistance in pre‐clinical models.Aims:To determine if IBER is pharmacodynamically (PD) active in multiple myeloma patients refractory to POM and/or LEN, and to establish pharmacokinetic (PK)/PD and PD/dose relationships.Methods:As of Jan 11, 2019, 83 patients received IBER as monotherapy or in combination with DEX; 61 (74%) were LEN refractory and 47 (57%) were POM refractory. Longitudinal immunohistochemistry (IHC) data on CRBN, Aiolos, Ikaros and ZFP91 expression was obtained from bone marrow samples from 14 patients dosed with 0.3–0.9 mg IBER daily ± DEX. PD analysis of immune activity by TruCulture® (n = 45) and by peripheral blood flow cytometry (n = 60) was completed on a subset of patients dosed up to 1.0 mg IBER ± DEX. A population PK approach was used to estimate exposure (area under the concentration curve over the 24 hr dosing interval [AUCτ]) on 59 patients dosed up to 1.0 mg IBER ± DEX.Results:IBER AUCτ increased in a dose‐proportional manner in RRMM patients over the dose range 0.3–1.0 mg (22.4–65.31 ng∗hr/mL, respectively). In patient biopsies analyzed to date, CRBN expression was observed in all tumors by IHC at baseline and did not significantly change while on‐treatment. Furthermore, no significant decrease in baseline CRBN expression was observed in patients refractory to POM. In MM cells, significant decreases in Aiolos (median 37% decrease, P < 0.001), Ikaros (median 12% decrease, P = 0.006), and ZFP91 (median 47% decrease, P < 0.001) protein expression were observed on‐treatment across all dose levels; these decreases were unrelated to levels of CRBN expression at screening or prior LEN or POM refractoriness. In TruCulture® samples, dose‐dependent increases were observed in IL‐2 and IFN‐γ, with median increases of 78% and 66%, respectively, 5 hours post 0.9 mg dose of IBER. A dose‐ and exposure‐dependent decrease in B‐cells was detected (median 74% decrease at cycle 2 day 15, IBER 0.9 mg). These observations are consistent with the proposed IBER mechanism of action. Immunoprofiling showed significant increases in total and proliferating NK cells in RRMM patients treated with IBER, and a dose‐dependent increase in proliferating, activated, and effector memory T‐cells. These trends were consistent in RRMM patients treated with IBER monotherapy and in combination with DEX.Summary/Conclusion:These translational analyses from IBER treated RRMM patients indicate it is pharmacodynamically active at the lowest dose (0.3 mg) and exhibits dose‐ and exposure‐dependent immunostimulatory activity, supporting further dose‐escalation beyond 1.0 mg, which is currently ongoing. These results also suggest that prior refractoriness to LEN or POM is not associated with significant loss of CRBN or IBER PD activity, supporting continued investigation of IBER in RRMM patients refractory to IMiD drugs.

Background:Venetoclax (Ven) is a highly selective, potent, oral BCL‐2 inhibitor that induces apoptosis in malignant cells dependent on BCL‐2 for survival. Proteasome inhibitors (PIs) and dexamethasone (d) were shown to increase BCL‐2 dependence in multiple myeloma (MM) cells, and preclinical studies showed enhanced inhibition of MM tumor growth with Ven+PI compared to either alone. Moreover, d has been shown to indirectly promote BCL‐2 dependency in MM cells. Clinical trials have since demonstrated efficacy of Ven in combination with the PI bortezomib in patients (pts) with relapsed/refractory MM (RRMM).Aims:We report interim data for Ven combined with second‐generation PI carfilzomib (K) and d in pts with RRMM.Methods:In this ongoing Phase 2 study (NCT02899052), pts with RRMM (1–3 prior lines of therapy) and no prior K exposure received VenKd on 28‐day cycles in 4 dose‐finding and 1 expansion cohort: Ven 400 mg/day + K 27 mg/m2 Day 1, 2, 8, 9, 15, 16 + d 40 mg Day 1, 8, 15, 22 (Cohort 1); same regimen but with Ven 800 mg/day (Cohort 2); Ven 800 mg/day + K 70 mg/m2 Day 1, 8, 15 + d 40 mg Day 1, 8, 15, 22 (Cohort 3/expansion cohort); or Ven 800 mg + K 56 mg/m2 Day 1, 2, 8, 9, 15, 16 + d 40 mg Day 1, 2, 8, 9, 15, 16, 22, 23 (Cohort 4). Treatment continued until progressive disease or unacceptable toxicity.Results:As of the clinical data cut‐off of 1 Feb 2019, 43 pts were enrolled. Median age was 67 (range, 37–79), 26 (62%) pts had ISS II/III disease, and 8 (19%) were t (11;14)+. Median number of prior lines of therapy was 2 (range, 1–3). Forty (93%) pts received prior PI (49% refractory), 33 (77%) received prior immunomodulatory drug (IMiD, 61% refractory), and 33 (77%) received prior PI+IMiD (33% double refractory).All pts had at least 1 adverse event (AE). The most common AEs of any grade were diarrhea (65%), nausea (49%), fatigue (47%), cough (35%), insomnia, dyspnea, vomiting, upper respiratory infection (33% each), lymphopenia (28%), thrombocytopenia, and dyspepsia (26% each). Thirty‐six (84%) pts had a Grade 3/4 AE, the most common being lymphopenia (23%), pneumonia, hypertension (16% each), and hypophosphatemia (12%).The overall response rate (ORR) was 79%, complete response or better (≥CR) rate was 40%, and very good partial response or better (≥VGPR) rate was 64% for all pts (Table). Median follow‐up for 42 pts was 10.4 months (95% CI = 8.0–13.8); 15 pts had progression‐free survival (PFS) events, with median PFS yet to be achieved. Baseline bone marrow core biopsy samples from 25 pts were evaluated for BCL‐2 expression by immunohistochemistry, with high expression (≥50% of tumor cells with moderate or higher cytoplasmic staining) seen in 23 (92%) samples. Pts with high BCL‐2 expression had response rates similar to the overall study population. Other correlative biomarker analyses are ongoing.Summary/Conclusion:The combination of VenKd was found to be tolerable with no new safety signals. VenKd demonstrates promising efficacy in pts with RRMM. The study remains ongoing with an additional 60 pts with RRMM enrolling to assess efficacy and safety in a larger group of pts with similar eligibility (Cohort 6) and t (11;14)+ pts (Cohort 7).image