The National STD Curriculum Podcast as a Method to Increase STI Education for Health Care Professionals.

BACKGROUND: Podcasts are a valuable educational tool that are convenient and provide on-demand learning. We launched the National Sexually Transmitted Disease Curriculum (NSTDC) Podcast in 2020 to educate healthcare professionals on sexually transmitted infections (STIs) with an emphasis on content from peer-reviewed literature relevant to clinical practice. METHODS: We describe the reach and usage data for 31 podcast episodes produced during the first 29 months. Information was obtained via Google Analytics, Apple Podcasts, the podcast hosting platform Buzzsprout, and the Health Professional Application for Training form for listeners who were registered on the NSTDC website. RESULTS: There were more than 21,000 downloads, with an average of 686 downloads per episode. Although 85% of downloads occurred in the United States, podcast visitors were located in 57 countries. The three most reported professions/disciplines were registered nurse (39.0%), advanced practice nurse (22.5%), and physician (11.3%). Forty-eight percent of visitors had a primary programmatic focus of STDs, 24% HIV/AIDs, and 18% primary care. CONCLUSION: The NSTDC Podcast is a highly utilized resource for mobile and on-demand learning for health care professionals who want to expand their knowledge on STIs.

CAR virus receptor mediates erythroid differentiation and migration and is downregulated in MDS.

Myelodysplastic syndromes (MDS) are myeloid neoplasms presenting with dysplasia in the bone marrow (BM) and peripheral cytopenia. In most patients anemia develops. We screened for genes that are expressed abnormally in erythroid progenitor cells (EP) and contribute to the pathogenesis of MDS. We found that the Coxsackie-Adenovirus receptor (CAR = CXADR) is markedly downregulated in CD45low/CD105+ EP in MDS patients compared to control EP. Correspondingly, the erythroblast cell lines HEL, K562, and KU812 stained negative for CAR. Lentiviral transduction of the full-length CXADR gene into these cells resulted in an increased expression of early erythroid antigens, including CD36, CD71, and glycophorin A. In addition, CXADR-transduction resulted in an increased migration against a serum protein gradient, whereas truncated CXADR variants did not induce expression of erythroid antigens or migration. Furthermore, conditional knock-out of Cxadr in C57BL/6 mice resulted in anemia and erythroid dysplasia. Finally, decreased CAR expression on EP was found to correlate with high-risk MDS and decreased survival. Together, CAR is a functionally relevant marker that is down-regulated on EP in MDS and is of prognostic significance. Decreased CAR expression may contribute to the maturation defect and altered migration of EP and thus their pathologic accumulation in the BM in MDS.

Antineoplastic efficacy profiles of avapritinib and nintedanib in KIT D816V+ systemic mastocytosis: a preclinical study.

Systemic mastocytosis (SM) is a hematopoietic neoplasm with a complex pathology and a variable clinical course. Clinical symptoms result from organ infiltration by mast cells (MC) and the effects of pro-inflammatory mediators released during MC activation. In SM, growth and survival of MC are triggered by various oncogenic mutant-forms of the tyrosine kinase KIT. The most prevalent variant, D816V, confers resistance against various KIT-targeting drugs, including imatinib. We examined the effects of two novel promising KIT D816V-targeting drugs, avapritinib and nintedanib, on growth, survival, and activation of neoplastic MC and compared their activity profiles with that of midostaurin. Avapritinib was found to suppress growth of HMC-1.1 cells (KIT V560G) and HMC-1.2 cells (KIT V560G + KIT D816V) with comparable IC50 values (0.1-0.25 µM). In addition, avapritinib was found to inhibit the proliferation of ROSAKIT WT cells, (IC50: 0.1-0.25 µM), ROSAKIT D816V cells (IC50: 1-5 µM), and ROSAKIT K509I cells (IC50: 0.1-0.25 µM). Nintedanib exerted even stronger growth-inhibitory effects in these cells (IC50 in HMC-1.1: 0.001-0.01 µM; HMC-1.2: 0.25-0.5 µM; ROSAKIT WT: 0.01-0.1 µM; ROSAKIT D816V: 0.5-1 µM; ROSAKIT K509I: 0.01-0.1 µM). Avapritinib and nintedanib also suppressed the growth of primary neoplastic cells in most patients with SM examined (avapritinib IC50: 0.5-5 µM; nintedanib IC50: 0.1-5 µM). Growth-inhibitory effects of avapritinib and nintedanib were accompanied by signs of apoptosis and decreased surface expression of the transferrin receptor CD71 in neoplastic MC. Finally, we were able to show that avapritinib counteracts IgE-dependent histamine secretion in basophils and MC in patients with SM. These effects of avapritinib may explain the rapid clinical improvement seen during treatment with this KIT inhibitor in patients with SM. In conclusion, avapritinib and nintedanib are new potent inhibitors of growth and survival of neoplastic MC expressing various KIT mutant forms, including D816V, V560G, and K509I, which favors the clinical development and application of these new drugs in advanced SM. Avapritinib is of particular interest as it also blocks mediator secretion in neoplastic MC.

BRD4 degradation blocks expression of MYC and multiple forms of stem cell resistance in Ph+ chronic myeloid leukemia.

In most patients with chronic myeloid leukemia (CML) clonal cells can be kept under control by BCR::ABL1 tyrosine kinase inhibitors (TKI). However, overt resistance or intolerance against these TKI may occur. We identified the epigenetic reader BRD4 and its downstream-effector MYC as growth regulators and therapeutic targets in CML cells. BRD4 and MYC were found to be expressed in primary CML cells, CD34+ /CD38- leukemic stem cells (LSC), and in the CML cell lines KU812, K562, KCL22, and KCL22T315I . The BRD4-targeting drug JQ1 was found to suppress proliferation in KU812 cells and primary leukemic cells in the majority of patients with chronic phase CML. In the blast phase of CML, JQ1 was less effective. However, the BRD4 degrader dBET6 was found to block proliferation and/or survival of primary CML cells in all patients tested, including blast phase CML and CML cells exhibiting the T315I variant of BCR::ABL1. Moreover, dBET6 was found to block MYC expression and to synergize with BCR::ABL1 TKI in inhibiting the proliferation in the JQ1-resistant cell line K562. Furthermore, BRD4 degradation was found to overcome osteoblast-induced TKI resistance of CML LSC in a co-culture system and to block interferon-gamma-induced upregulation of the checkpoint antigen PD-L1 in LSC. Finally, dBET6 was found to suppress the in vitro survival of CML LSC and their engraftment in NSG mice. Together, targeting of BRD4 and MYC through BET degradation sensitizes CML cells against BCR::ABL1 TKI and is a potent approach to overcome multiple forms of drug resistance in CML LSC.

CDK4/CDK6 Inhibitors Synergize with Midostaurin, Avapritinib, and Nintedanib in Inducing Growth Inhibition in KIT D816V+ Neoplastic Mast Cells.

In most patients with advanced systemic mastocytosis (AdvSM), neoplastic mast cells (MC) express KIT D816V. However, despite their disease-modifying potential, KIT D816V-targeting drugs, including midostaurin and avapritinib, may not produce long-term remissions in all patients. Cyclin-dependent kinase (CDK) 4 and CDK6 are promising targets in oncology. We found that shRNA-mediated knockdown of CDK4 and CDK6 results in growth arrest in the KIT D816V+ MC line HMC-1.2. The CDK4/CDK6 inhibitors palbociclib, ribociclib, and abemaciclib suppressed the proliferation in primary neoplastic MC as well as in all HMC-1 and ROSA cell subclones that were examined. Abemaciclib was also found to block growth in the drug-resistant MC line MCPV-1, whereas no effects were seen with palbociclib and ribociclib. Anti-proliferative drug effects on MC were accompanied by cell cycle arrest. Furthermore, CDK4/CDK6 inhibitors were found to synergize with the KIT-targeting drugs midostaurin, avapritinib, and nintedanib in inducing growth inhibition and apoptosis in neoplastic MCs. Finally, we found that CDK4/CDK6 inhibitors induce apoptosis in CD34+/CD38- stem cells in AdvSM. Together, CDK4/CDK6 inhibition is a potent approach to suppress the growth of neoplastic cells in AdvSM. Whether CDK4/CDK6 inhibitors can improve clinical outcomes in patients with AdvSM remains to be determined in clinical trials.

Direct and Indirect Effects of a Project ECHO Longitudinal Clinical Tele-Mentoring Program on Viral Suppression for Persons With HIV: A Population-Based Analysis.

BACKGROUND: Project Extension for Community Health Outcomes (ECHO) aims to connect community providers to academic specialists, deliver longitudinal clinical mentorship and case consultations, plus encourage dissemination of knowledge and resources. The impact on outcomes for persons with HIV (PWH) is uncertain. SETTING: PWH in Washington and Oregon outside of the Seattle and Portland metro areas, January 2011 to March 2018. METHODS: Using viral load (VL) surveillance data, we assessed difference in the percentage of PWH who were virally suppressed among PWH whose providers participated versus did not participate in Project ECHO. Analyses included multiple mixed-effects regression models, adjusting for time and for patient, provider, and clinic characteristics. RESULTS: Based on 65,623 VL results, Project ECHO participation was associated with an increase in the percentage of patients with VL suppression (13.7 percentage points greater; P < 0.0001), although the effect varied by estimated provider PWH patient volume. The difference was 14.7 percentage points ( P < 0.0001) among patients of providers who order <20 VL's/quarter and 2.3 and -0.6 percentage points among patients of providers who order 20-40 or >40 VL's/quarter, respectively ( P > 0.5). The magnitude of difference in VL suppression was associated with the number of sessions attended. Among patients of lower-volume providers who did not participate, VL suppression was 6.2 percentage points higher if providers worked in a clinic where another provider did participate ( P < 0.0001). CONCLUSION: Project ECHO is associated with improvement in VL suppression for PWH whose providers participate or work in the same clinic system as a provider who participates, primarily because of benefits for patients of lower-volume providers.

Secondary basophilic leukemia in Ph-negative myeloid neoplasms: A distinct subset with poor prognosis.

During progression of myeloid neoplasms, the basophil compartment may expand substantially and in some of these patients, a basophilic leukemia is diagnosed. In patients with Ph-chromosome+ chronic myeloid leukemia, acceleration of disease is typically accompanied by marked basophilia. In other myeloid neoplasms, secondary leukemic expansion of basophils is rarely seen. We report on 5 patients who suffered from a myelodysplastic syndrome, myeloproliferative neoplasm, or acute leukemia and developed a massive expansion of basophils during disease progression. In 4 of 5 patients, peripheral blood basophil counts reached 40%, and the diagnosis "secondary basophilic leukemia" was established. As assessed by flow cytometry, neoplastic basophils expressed CD9, CD18, CD25, CD33, CD63, PD-L1, CD123, and CLL-1. In addition, basophils were found to display BB1 (basogranulin), 2D7, tryptase and KIT. In 4 of 5 patients the disease progressed quickly and treatment with azacitidine was started. However, azacitidine did not induce major clinical responses, and all patients died from progressive disease within 3 Y. In in vitro experiments, the patients´ cells and the basophilic leukemia cell line KU812 showed variable responses to targeted drugs, including azacitidine, venetoclax, hydroxyurea, and cytarabine. A combination of venetoclax and azacitidine induced cooperative antineoplastic effects in these cells. Together, secondary basophilic leukemia has a poor prognosis and monotherapy with azacitidine is not sufficient to keep the disease under control for longer time-periods. Whether drug combination, such as venetoclax+azacitidine, can induce better outcomes in these patients remains to be determined in future clinical studies.

Leveraging E-Learning Infrastructure in Times of Rapid Change: Use of the National Sexually Transmitted Diseases Curriculum in the Era of COVID-19.

ABSTRACT: The National Sexually Transmitted Diseases Curriculum is an e-learning platform. New registrations and learning group creations in March to April 2020 were compared with previous 12-month data. Substantial increases in registrations and learning groups demonstrate that the National Sexually Transmitted Diseases Curriculum was successfully leveraged to meet rapidly shifting training needs due to the COVID-19 pandemic.

Potential for community based surveillance of febrile diseases: Feasibility of self-administered rapid diagnostic tests in Iquitos, Peru and Phnom Penh, Cambodia.

Rapid diagnostic tests (RDTs) have the potential to identify infectious diseases quickly, minimize disease transmission, and could complement and improve surveillance and control of infectious and vector-borne diseases during outbreaks. The U.S. Defense Threat Reduction Agency's Joint Science and Technology Office (DTRA-JSTO) program set out to develop novel point-of-need RDTs for infectious diseases and deploy them for home use with no training. The aim of this formative study was to address two questions: 1) could community members in Iquitos, Peru and Phnom Penh, Cambodia competently use RDTs of different levels of complexity at home with visually based instructions provided, and 2) if an RDT were provided at no cost, would it be used at home if family members displayed febrile symptoms? Test kits with written and video (Peru only) instructions were provided to community members (Peru [n = 202]; Cambodia [n = 50]) or community health workers (Cambodia [n = 45]), and trained observers evaluated the competency level for each of the several steps required to successfully operate one of two multiplex RDTs on themselves or other consenting participant (i.e., family member). In Iquitos, >80% of residents were able to perform 11/12 steps and 7/15 steps for the two- and five-pathogen test, respectively. Competency in Phnom Penh never reached 80% for any of the 12 or 15 steps for either test; the percentage of participants able to perform a step ranged from 26-76% and 23-72%, for the two- and five-pathogen tests, respectively. Commercially available NS1 dengue rapid tests were distributed, at no cost, to households with confirmed exposure to dengue or Zika virus; of 14 febrile cases reported, six used the provided RDT. Our findings support the need for further implementation research on the appropriate level of instructions or training needed for diverse devices in different settings, as well as how to best integrate RDTs into existing local public health and disease surveillance programs at a large scale.

Phenotypic characterization of leukemia-initiating stem cells in chronic myelomonocytic leukemia.

Chronic myelomonocytic leukemia (CMML) is a stem cell-derived neoplasm characterized by dysplasia, uncontrolled expansion of monocytes, and substantial risk to transform to secondary acute myeloid leukemia (sAML). So far, little is known about CMML-initiating cells. We found that leukemic stem cells (LSC) in CMML reside in a CD34+/CD38- fraction of the malignant clone. Whereas CD34+/CD38- cells engrafted NSGS mice with overt CMML, no CMML was produced by CD34+/CD38+ progenitors or the bulk of CD34- monocytes. CMML LSC invariably expressed CD33, CD117, CD123 and CD133. In a subset of patients, CMML LSC also displayed CD52, IL-1RAP and/or CLL-1. CMML LSC did not express CD25 or CD26. However, in sAML following CMML, the LSC also expressed CD25 and high levels of CD114, CD123 and IL-1RAP. No correlations between LSC phenotypes, CMML-variant, mutation-profiles, or clinical course were identified. Pre-incubation of CMML LSC with gemtuzumab-ozogamicin or venetoclax resulted in decreased growth and impaired engraftment in NSGS mice. Together, CMML LSC are CD34+/CD38- cells that express a distinct profile of surface markers and target-antigens. During progression to sAML, LSC acquire or upregulate certain cytokine receptors, including CD25, CD114 and CD123. Characterization of CMML LSC should facilitate their enrichment and the development of LSC-eradicating therapies.

Degradation of BRD4 - a promising treatment approach not only for hematologic but also for solid cancer.

Bromodomain (BRD) and extra-terminal (BET) proteins are epigenetic readers that regulate gene expression and promote cancer evolution. Pharmacological inactivation of BRD4 has recently been introduced as a promising anti-neoplastic approach that targets MYC oncogene expression. However, resistance against BRD4-targeting drugs has been described. We compared the efficacy of the small-molecule-type BET BRD inhibitor JQ1 with the recently developed BET protein degraders dBET1 and dBET6 in colon, breast, melanoma, ovarian, lung and prostate cancer cell lines. As determined by qPCR, all BRD4 targeting drugs dose-dependently decreased MYC expression, with dBET6 introducing the strongest downregulation of MYC. This correlated with the anti-proliferative activity of these drugs, which was at least one order of magnitude higher for dBET6 (IC50 0.001-0.5 µM) than for dBET1 or JQ1 (IC50 0.5-5 µM). Interestingly, when combined with commonly used cytotoxic therapeutics, dBET6 was found to promote anti-neoplastic effects and to counteract chemoresistance in most cancer cell lines. Moreover, JQ1 and both BET degraders strongly downregulated baseline and interferon-gamma induced expression of the immune checkpoint molecule PD-L1 in all cancer cell lines. Together, our data suggest that dBET6 outperforms first-generation BRD4 targeting drugs like dBET1 and JQ1, and decreases chemoresistance and immune resistance of cancer.

PI3-kinase inhibition as a strategy to suppress the leukemic stem cell niche in Ph+ chronic myeloid leukemia.

Recent data suggest that the disease-associated microenvironment, known as the leukemic stem cell (LSC) niche, is substantially involved in drug resistance of LSC in BCR-ABL1+ chronic myeloid leukemia (CML). Attacking the LSC niche in CML may thus be an effective approach to overcome drug resistance. We have recently shown that osteoblasts are a major site of niche-mediated LSC resistance against second- and third-generation tyrosine kinase inhibitors (TKI) in CML. In the present study, we screened for drugs that are capable of suppressing the growth and viability of osteoblasts and/or other niche cells and can thereby overcome TKI resistance of CML LSC. Proliferation was analyzed by determining 3H-thymidine uptake in niche-related cells, and apoptosis was measured by Annexin-V/DAPI-staining and flow cytometry. We found that the dual PI3 kinase (PI3K) and mTOR inhibitor BEZ235 and the selective pan-PI3K inhibitor copanlisib suppress proliferation of primary osteoblasts (BEZ235 IC50: 0.05 µM; copanlisib IC50: 0.05 µM), the osteoblast cell line CAL-72 (BEZ235 IC50: 0.5 µM; copanlisib IC50: 1 µM), primary umbilical vein-derived endothelial cells (BEZ235 IC50: 0.5 µM; copanlisib IC50: 0.5 µM), and the vascular endothelial cell line HMEC-1 (BEZ235 IC50: 1 µM; copanlisib IC50: 1 µM), whereas no comparable effects were seen with the mTOR inhibitor rapamycin. Furthermore, we show that BEZ235 and copanlisib cooperate with nilotinib and ponatinib in suppressing proliferation and survival of osteoblasts and endothelial cells. Finally, BEZ235 and copanlisib were found to overcome osteoblast-mediated resistance against nilotinib and ponatinib in K562 cells, KU812 cells and primary CD34+/CD38- CML LSC. Together, targeting osteoblastic niche cells through PI3K inhibition may be a new effective approach to overcome niche-induced TKI resistance in CML. Whether this approach can be translated into clinical application and can counteract drug resistance of LSC in patients with CML remains to be determined in clinical trials.

Cell-based and antibody-mediated immunotherapies directed against leukemic stem cells in acute myeloid leukemia: Perspectives and open issues.

Despite new insights in molecular features of leukemic cells and the availability of novel treatment approaches and drugs, acute myeloid leukemia (AML) remains a major clinical challenge. In fact, many patients with AML relapse after standard therapy and eventually die from progressive disease. The basic concept of leukemic stem cells (LSC) has been coined with the goal to decipher clonal architectures in various leukemia-models and to develop curative drug therapies by eliminating LSC. Indeed, during the past few years, various immunotherapies have been tested in AML, and several of these therapies follow the strategy to eliminate relevant leukemic subclones by introducing LSC-targeting antibodies or LSC-targeting immune cells. These therapies include, among others, new generations of LSC-eliminating antibody-constructs, checkpoint-targeting antibodies, bi-specific antibodies, and CAR-T or CAR-NK cell-based strategies. However, responses are often limited and/or transient which may be due to LSC resistance. Indeed, AML LSC exhibit multiple forms of resistance against various drugs and immunotherapies. An additional problems are treatment-induced myelotoxicity and other side effects. The current article provides a short overview of immunological targets expressed on LSC in AML. Moreover, cell-based therapies and immunotherapies tested in AML are discussed. Finally, the article provides an overview about LSC resistance and strategies to overcome resistance.

Evaluation of the National Sexually Transmitted Disease Curriculum: Reach, Utilization, and Engagement.

BACKGROUND: With increasing rates of sexually transmitted infections in the United States, there is a critical need to educate health professionals on the prevention, diagnosis, and treatment of sexually transmitted infections. The National Sexually Transmitted Disease Curriculum (NSTDC, https://www.std.uw.edu) is a free, online curriculum, funded by the Centers for Disease Control and Prevention. The purpose of this article is to evaluate the reach, utilization, and engagement of users with the curriculum. METHODS: Data on NSTDC utilization was collected for 24 months after the February 1, 2017 launch. For all users, Google Analytics was used to determine total number of users, geographic location, age and sex, and average session duration. For registered users, additional data analysis included work-role, demographics, and completion of self-study modules, check-on-learning questions, and question banks. User satisfaction was measured on a 5-point Likert scale. RESULTS: During the evaluation period, 136,270 individual users accessed the NSTDC, including 24,652 registered users. Among all registered users, 10,660 (43.2%) were registered nurses, 2810 (11.4%) physicians, 4942 (20.1%) Advanced Practice Nurses and Physician Assistants, and 6213 (25.2%) nonclinicians. Among registered users, 18,533 (75.2%) completed at least 1 module, 7898 (32.0%) completed all 7 modules, and 19,804 (80.4%) answered optional check-on-learning questions. Median satisfaction with the content was (5) very satisfied (interquartile range, 4-5). CONCLUSIONS: The NSTDC is a free, guideline-based, online curriculum with novel dual functionality that has achieved extensive reach with a broad array of health professionals who engage deeply with the material. The wide usage of NSTDC demonstrates the need for high-quality, unbiased, free content in user-focused formats.

Redistribution, homing and organ-invasion of neoplastic stem cells in myeloid neoplasms.

The development of a myeloid neoplasm is a step-wise process that originates from leukemic stem cells (LSC) and includes pre-leukemic stages, overt leukemia and a drug-resistant terminal phase. Organ-invasion may occur in any stage, but is usually associated with advanced disease and a poor prognosis. Sometimes, extra-medullary organ invasion shows a metastasis-like or even sarcoma-like destructive growth of neoplastic cells in local tissue sites. Examples are myeloid sarcoma, mast cell sarcoma and localized blast phase of chronic myeloid leukemia. So far, little is known about mechanisms underlying re-distribution and extramedullary dissemination of LSC in myeloid neoplasms. In this article, we discuss mechanisms through which LSC can mobilize out of the bone marrow niche, can transmigrate from the blood stream into extramedullary organs, can invade local tissue sites and can potentially create or support the formation of local stem cell niches. In addition, we discuss strategies to interfere with LSC expansion and organ invasion by targeted drug therapies.

Potential Use of Community-Based Rapid Diagnostic Tests for Febrile Illnesses: Formative Research in Peru and Cambodia.

In 2012, the U.S. Defense Threat Reduction Agency Joint Science and Technology Office initiated a program to develop novel point-of-need diagnostic devices for surveillance of emerging infectious diseases including dengue, malaria, plague, and melioidosis. Prior to distribution of devices to observe their correct use among community members in Iquitos, Peru, and Phnom Penh, Cambodia, research was conducted to: 1) assess acceptability of use, including the motivation to use a rapid diagnostic test (RDT) before or instead of seeking care at a health facility, 2) explore comprehension of RDT use instructions, and 3) examine possible strategies for large scale RDT distribution and use at each site. In February 2014, 9 focus group discussions (FGD) with community members and 5 FGD with health professionals were conducted in Iquitos, and 9 FGD with community members and 9 in-depth interviews with health professionals in Phnom Penh. In both places, participants agreed to use the device themselves (involving finger prick) or could identify someone who could do so in their home or neighborhood. The main incentive to RDT use in both sites was the ability for device results to be used for care facilitation (post confirmatory tests), specifically reduced wait times to be seen or obtain a diagnosis. Comprehension of RDT use instructions was assessed in Iquitos by asking some participants to apply the device to research team members; after watching a short video, most steps were done correctly. In Phnom Penh, participants were asked to describe each step after reading the instructions; they struggled with comprehension. Health professionals' main concerns in both sites were their community's ability to accurately use the test, handle complicated instructions, and safety (i.e., disposal of lancets). Health system structure and ability to use home diagnostic devices varied in the two disease endemic sites, with substantial challenges in each, suggesting the need for different strategies for RDT large scale community use, and illustrating the value of formative research before deployment of novel technologies.

A kinase-independent role for CDK8 in BCR-ABL1+ leukemia.

Cyclin-dependent kinases (CDKs) are frequently deregulated in cancer and represent promising drug targets. We provide evidence that CDK8 has a key role in B-ALL. Loss of CDK8 in leukemia mouse models significantly enhances disease latency and prevents disease maintenance. Loss of CDK8 is associated with pronounced transcriptional changes, whereas inhibiting CDK8 kinase activity has minimal effects. Gene set enrichment analysis suggests that the mTOR signaling pathway is deregulated in CDK8-deficient cells and, accordingly, these cells are highly sensitive to mTOR inhibitors. Analysis of large cohorts of human ALL and AML patients reveals a significant correlation between the level of CDK8 and of mTOR pathway members. We have synthesized a small molecule YKL-06-101 that combines mTOR inhibition and degradation of CDK8, and induces cell death in human leukemic cells. We propose that simultaneous CDK8 degradation and mTOR inhibition might represent a potential therapeutic strategy for the treatment of ALL patients.

Immunotherapy-Based Targeting and Elimination of Leukemic Stem Cells in AML and CML.

The concept of leukemic stem cells (LSC) has been developed with the idea to explain the clonal hierarchies and architectures in leukemia, and the more or less curative anti-neoplastic effects of various targeted drugs. It is now widely accepted that curative therapies must have the potential to eliminate or completely suppress LSC, as only these cells can restore and propagate the malignancy for unlimited time periods. Since LSC represent a minor cell fraction in the leukemic clone, little is known about their properties and target expression profiles. Over the past few years, several cell-specific immunotherapy concepts have been developed, including new generations of cell-targeting antibodies, antibody-toxin conjugates, bispecific antibodies, and CAR-T cell-based strategies. Whereas such concepts have been translated and may improve outcomes of therapy in certain lymphoid neoplasms and a few other malignancies, only little is known about immunological targets that are clinically relevant and can be employed to establish such therapies in myeloid neoplasms. In the current article, we provide an overview of the immunologically relevant molecular targets expressed on LSC in patients with acute myeloid leukemia (AML) and chronic myeloid leukemia (CML). In addition, we discuss the current status of antibody-based therapies in these malignancies, their mode of action, and successful examples from the field.

Effects of ibrutinib on proliferation and histamine release in canine neoplastic mast cells.

The Bruton's tyrosine kinase (BTK) inhibitor ibrutinib is effective in the treatment of human chronic lymphocytic leukaemia and mantle cell lymphoma. Recent data have shown that ibrutinib also blocks IgE-dependent activation and histamine release in human basophils (BAs) and mast cells (MCs). The aim of this study was to investigate whether BTK serves as a novel therapeutic target in canine mast cell tumours (MCTs). We evaluated the effects of ibrutinib on two canine MC lines, C2 and NI-1 and on primary MCs obtained from canine MCTs (n = 3). Using flow cytometry, we found that ibrutinib suppresses phosphorylation of BTK and of downstream STAT5 in both MC lines. In addition, ibrutinib decreased proliferation of neoplastic MCs, with IC50 values ranging between 0.1 and 1 µM in primary MCT cells and between 1 and 3 µM in C2 and NI-1 cells. In C2 cells, the combination "ibrutinib + midostaurin" produced synergistic growth-inhibitory effects. At higher concentrations, ibrutinib also induced apoptosis in both MC lines. Finally, ibrutinib was found to suppress IgE-dependent histamine release in primary MCT cells, with IC50 values ranging from 0.05 to 0.1 µM in NI-1 cells, and from 0.05 to 1 µM in primary MCT cells. In summary, ibrutinib exerts anti-proliferative effects in canine neoplastic MCs and counteracts IgE-dependent histamine release in these cells. Based on our data, ibrutinib may be considered as a novel therapeutic agent for the treatment of canine MCT. The value of BTK inhibition in canine MCT patients remains to be elucidated in clinical trials.

Remote programming of cochlear implants in users of all ages.

BACKGROUND: Remote programming for adult cochlear implant (CI) users is feasible, safe, and effective. Limited evidence, however, exists on if remote CI programming can also be productively done with paediatric CI users. AIMS/OBJECTIVES: To assess the safety and feasibility of remote CI programming in CI users for all ages. MATERIALS AND METHODS: Forty-six (25 children, 21 adults) experienced CI users were fit locally and remotely. The results of these two fitting sessions were compared in terms of safety, Impedance Field Telemetry (IFT), Maximum Comfortable Levels (MCL), Threshold Levels (THR), audiometry, fitting duration, and speech understanding. RESULTS: The subjects' safety was not compromised during any of the fitting procedures. No significant difference was found for IFT, MCL, THR, audiometry, or speech understanding for either remote or local fitting. Remote fittings took slightly longer than local fittings when only the fitting time itself was measured. CONCLUSIONS AND SIGNIFICANCE: Remote follow-up fitting is as safe, feasible, and effective as local fitting for CI users of all ages. A more extensive adoption of remote fitting may allow many CI users greater access to clinics and therefore increased benefit from CI use.