Reversal of MYB-dependent suppression of MAFB expression overrides leukaemia phenotype in MLL-rearranged AML

The transcription factor MYB plays a pivotal role in haematopoietic homoeostasis and its aberrant expression is involved in the genesis and maintenance of acute myeloid leukaemia (AML). We have previously demonstrated that not all AML subtypes display the same dependency on MYB expression and that such variability is dictated by the nature of the driver mutation. However, whether this difference in MYB dependency is a general trend in AML remains to be further elucidated. Here, we investigate the role of MYB in human leukaemia by performing siRNA-mediated knock-down in cell line models of AML with different driver lesions. We show that the characteristic reduction in proliferation and the concomitant induction of myeloid differentiation that is observed in MLL-rearranged and t(8;21) leukaemias upon MYB suppression is not seen in AML cells with a complex karyotype. Transcriptome analyses revealed that MYB ablation produces consensual increase of MAFB expression in MYB-dependent cells and, interestingly, the ectopic expression of MAFB could phenocopy the effect of MYB suppression. Accordingly, in silico stratification analyses of molecular data from AML patients revealed a reciprocal relationship between MYB and MAFB expression, highlighting a novel biological interconnection between these two factors in AML and supporting new rationales of MAFB targeting in MLL-rearranged leukaemias.

Mechanisms of Intrinsic Radioresistance in Breast Cancer Identify Potential Therapeutic Vulnerabilities

PURPOSE/OBJECTIVE(S)

Clinical management of breast cancer (BC) includes radiation therapy (RT) for most women, though the molecular mechanisms that underly RT response and intrinsic radioresistance are poorly understood. Both in vitro and in vivo models aid in our understanding of radiobiology, and we hypothesized that transcriptional changes caused by radiation in vitro in BC cell lines would be recapitulated in an in vivo mouse xenograft model and uncover targetable mechanisms of radioresistance in BC.

MATERIALS/METHODS

Radiosensitivity was measured with clonogenic survival assays in 16 cell lines. RNA-seq experiments in vitro and in vivo were performed in an RT resistant (SUM-159) and RT sensitive (ZR-75) cell line 24 hrs after 4 Gy or after 2 Gy x 6 fractions, respectively. Differentially expressed genes (DEGs) were identified from RNA-seq data with DeSeq2 followed by pathway analysis with iPathwayGuide.

RESULTS

RT sensitivity was subtype independent in 16 BC cell lines, with SUM-159 radioresistant (SF 0.88) and ZR-75-1 radiosensitive (SF 0.29). There were 75 unique pathways that were significantly altered after RT in SUM-159 cells (53 pathways in vivo only, 36 pathways in vitro only, 14 both conditions; adjusted p-value < 0.05) and 85 unique pathways that were significantly altered after RT in ZR-75-1 cells (16 pathways in vivo only, 72 in vivo only, 3 both conditions; adjusted p-value < 0.05). Pathways that were significantly affected in both cell lines exclusively in the in vitro condition include canonical RT response pathways such as cell cycle, cellular senescence, and DNA replication, though the direction of DEGs were opposite in the two cell lines for each of these pathways. The IL-17 signaling pathway was significantly altered for both cell lines in vivo. Of the pathways that were significantly altered in both conditions for SUM-159 cells, inflammation, including chemokine signaling pathway and cytokine-cytokine receptor interaction, were among the most significant. Significantly more cytokines were upregulated following RT in vivo than in vitro. Cytokines were not upregulated in ZR-75-1 cells in vitro or in vivo.

CONCLUSION

Taken together, the significant changes in the IL-17 pathway and the upregulation of cytokines only in vivo indicate a potential of the tumor microenvironment in the in vivo condition that the in vitro condition lacks. Increased heterogeneity in vivo relative to in vitro may also explain the absence of several canonical RT response pathways in the in vivo conditions for each cell line. Notably, the opposite direction of DEG changes in the canonical RT response pathways between the 2 cell lines with disparate radiosensitivity levels may point to important biologic vulnerabilities that may be targeted in the resistant SUM-159 cells. Future studies are underway using additional BC cell lines and single-cell analysis to better understand RT response heterogeneity.

Transcriptomic Analysis to Uncover the Mechanism of Radiosensitization of AR-Positive Triple Negative Breast Cancers with AR Inhibition

PURPOSE/OBJECTIVE(S)

The androgen receptor (AR) has been shown to drive tumor growth in triple negative breast cancers (TNBC), and previous work demonstrated AR inhibition as a strategy for radiosensitization in AR-positive (AR+) TNBC. Despite its role in radioresistance, the mechanistic role of AR in response to radiation therapy (RT) remains unknown, as does the benefit of 2nd generation anti-androgens in this context. We hypothesized that all 2nd generation anti-AR therapy would radiosensitize similarly and that canonical AR transcriptional function was responsible for radioresistance in these models.

MATERIALS/METHODS

Radiosensitization was assessed using 2nd generation AR antagonists (apalutamide, enzalutamide, and darolutamide) using clonogenic survival assays in MDA-MB-453, SUM185, MFM-223, and MDA-MB-231 cells at 2-6Gy. Cellular fractionation experiments were performed and quantitated to determine the location of the AR protein in cells treated with AR agonists +/- RT. RNA Seq was performed and transcriptomic approaches were used (Advaita iPathway analysis) to investigate AR-mediated effects in response to RT.

RESULTS

Inhibition with the 2nd generation anti-androgens enzalutamide and apalutamide is sufficient to radiosensitize AR+ TNBC models (rER: 1.34-1.41); while darolutamide had no effect on radiosensitivity (rER: 0.96-1.11). Additionally, TNBC cells with low AR expression were not radiosensitized by AR inhibition with any drug (rER: 0.96-1.03). While stimulation with the synthetic androgen methyltrienolone R1881 is sufficient to induce nuclear translocation of AR in AR+ TNBC cells, AR inhibition with enzalutamide, apalutamide, or darolutamide blocked AR nuclear translocation under growth conditions with charcoal stripped serum or fetal bovine serum. When cells are treated with R1881+RT, nuclear translocation of AR was induced at similar or greater levels compared to R1881 alone in AR+ TNBC cells. Combination treatment of RT with enzalutamide in the presence of hormones reduced nuclear localization of AR (32-39% reduction) compared to RT alone. RNA-sequencing after RT identified transcriptional changes potentially regulated by AR+RT, including changes in the NHEJ pathway genes. Additionally, pathway analyses in these models demonstrated changes in the MAPK/ERK signaling pathway, among others, that may regulate RT resistance in AR+ TNBC models.

CONCLUSION

Most 2nd generation anti-androgens confer radiosensitization in AR+ TNBC models with cellular localization changes of AR noted after RT. The known structural differences amongst 2nd generation anti-androgens may account for differences in radiosensitization noted. Furthermore, AR-mediated radioresistance may be due, at least in part, to downstream MAPK/ERK signaling. This work builds on the mechanistic understanding of AR-mediated radioresistance in AR+ TNBC and may expose vulnerabilities to overcome resistance to combination treatment with AR inhibition and RT.

Depression, anxiety and PTSD symptoms before and during the COVID-19 pandemic in the UK

BACKGROUND

The impact of the coronavirus disease 2019 (COVID-19) pandemic on mental health is still being unravelled. It is important to identify which individuals are at greatest risk of worsening symptoms. This study aimed to examine changes in depression, anxiety and post-traumatic stress disorder (PTSD) symptoms using prospective and retrospective symptom change assessments, and to find and examine the effect of key risk factors.

METHOD

Online questionnaires were administered to 34 465 individuals (aged 16 years or above) in April/May 2020 in the UK, recruited from existing cohorts or via social media. Around one-third (n = 12 718) of included participants had prior diagnoses of depression or anxiety and had completed pre-pandemic mental health assessments (between September 2018 and February 2020), allowing prospective investigation of symptom change.

RESULTS

Prospective symptom analyses showed small decreases in depression (PHQ-9: -0.43 points) and anxiety [generalised anxiety disorder scale - 7 items (GAD)-7: -0.33 points] and increases in PTSD (PCL-6: 0.22 points). Conversely, retrospective symptom analyses demonstrated significant large increases (PHQ-9: 2.40; GAD-7 = 1.97), with 55% reported worsening mental health since the beginning of the pandemic on a global change rating. Across both prospective and retrospective measures of symptom change, worsening depression, anxiety and PTSD symptoms were associated with prior mental health diagnoses, female gender, young age and unemployed/student status.

CONCLUSIONS

We highlight the effect of prior mental health diagnoses on worsening mental health during the pandemic and confirm previously reported sociodemographic risk factors. Discrepancies between prospective and retrospective measures of changes in mental health may be related to recall bias-related underestimation of prior symptom severity.

The effect of postprandial exercise on mean blood glucose concentrations following high and maintenance carbohydrate content meals in healthy dogs

OBJECTIVES

To compare the effect of 15 min of exercise 30 min post-meal on mean blood glucose concentrations in 5 well-conditioned versus 5 over-conditioned dogs. To compare the effect of exercise on glycemic control in dogs eating their maintenance diet as compared to a high carbohydrate meal.

ANIMALS

Ten healthy staff or student owned dogs, five well- and five over-conditioned.

PROCEDURES

This was a crossover study over 5 days. Continuous glucose monitors (CGM) were placed on day 1. On days 2 and 3, dogs received their maintenance diet and a high carbohydrate meal, respectively and were walked on the treadmill for 15 min following each meal. On day 4, dogs were given their maintenance diet in hospital without treadmill activity. On day 5, the CGM were removed. The mean blood glucose 30 min post-meal, during exercise, 15 min after completing exercise, and the 1-3 h period after completing the exercise were compared to detect any effect of exercise, diet composition, or body condition.

RESULTS

Dogs consuming a high carbohydrate meal had a significantly higher mean blood glucose 15 min post-exercise. Mean glucose values at all time points following a high carbohydrate meal were significantly higher than mean glucose values on the non-exercise day.

CONCLUSIONS AND CLINICAL RELEVANCE

No impact of post-prandial exercise on glucose concentrations were identified in this study, however, the carbohydrate content of the meal impacted post-prandial glycemic responses in healthy dogs regardless of body condition. Evaluating the impact of post-prandial exercise in insulin-dependent or glucose-intolerant dogs is warranted to determine if these findings persist.

Blood cadmium, lead, manganese, mercury, and selenium levels in American Indian populations: The Strong Heart Study

BACKGROUND

Many American Indian (AI) communities are in areas affected by environmental contamination, such as toxic metals. However, studies assessing exposures in AI communities are limited. We measured blood metals in AI communities to assess historical exposure and identify participant characteristics associated with these levels in the Strong Heart Study (SHS) cohort.

METHOD

Archived blood specimens collected from participants (n = 2014, all participants were 50 years of age and older) in Arizona, Oklahoma, and North and South Dakota during SHS Phase-III (1998-1999) were analyzed for cadmium, lead, manganese, mercury, and selenium using inductively coupled plasma triple quadrupole mass spectrometry. We conducted descriptive analyses for the entire cohort and stratified by selected subgroups, including selected demographics, health behaviors, income, waist circumference, and body mass index. Bivariate associations were conducted to examine associations between blood metal levels and selected socio-demographic and behavioral covariates. Finally, multivariate regression models were used to assess the best model fit that predicted blood metal levels.

FINDINGS

All elements were detected in 100% of study participants, with the exception of mercury (detected in 73% of participants). The SHS population had higher levels of blood cadmium and manganese than the general U.S. population 50 years and older. The median blood mercury in the SHS cohort was at about 30% of the U.S. reference population, potentially due to low fish consumption. Participants in North Dakota and South Dakota had the highest blood cadmium, lead, manganese, and selenium, and the lowest total mercury levels, even after adjusting for covariates. In addition, each of the blood metals was associated with selected demographic, behavioral, income, and/or weight-related factors in multivariate models. These findings will help guide the tribes to develop education, outreach, and strategies to reduce harmful exposures and increase beneficial nutrient intake in these AI communities.

Treatment of Patients with Waldenström Macroglobulinaemia: Clinical practice update from the Myeloma Foundation of Australia Medical and Scientific Advisory Group

Waldenström macroglobulinaemia (WM) is an indolent B-cell malignancy characterised by the presence of IgM paraprotein, bone marrow infiltration by clonal small B lymphocytes with plasmacytic differentiation and the MYD88 L265P mutation in >90% of cases. Traditionally, WM has been treated with chemoimmunotherapy. Recent trials have demonstrated the efficacy and safety of Bruton tyrosine kinase inhibitors in WM, both as monotherapy and in combination with other drugs. There is emerging evidence on use of other agents including BCL2 inhibitors and on treatment of rare presentations of WM. In this update, the Medical and Scientific Advisory Group of Myeloma Australia review the available evidence on the treatment of WM since the last publication in 2017 and provide specific recommendations to assist Australian clinicians in the management of this disease.

Pain Catastrophizing and Functional Disability in Youth with Chronic Pain: An Examination of Indirect Effects

Pediatric pain conditions are not uncommon and may lead to functional disability. The purpose of this study is to examine indirect effects of pain catastrophizing on functional disability through anxiety, depression, and pain in youth with chronic pain. Participants included 197 youth (144 females, Mage = 14.67 years) with chronic pain conditions. Youth completed self-report measures of pain catastrophizing, depression, anxiety, pain intensity, and functional disability. Caregivers also completed a measure of youth functional disability. Using a cross-sectional design, a multiple mediator model was estimated with pain catastrophizing as the predictor, functional disability as the outcome, and depression, anxiety, and pain intensity as mediators. Results supported a mediation model in which depression (B = 0.1145, SE = 0.0528, Z = 2.1686; B = 0.1512, SE = 0.0585, Z = 2.5846) and pain intensity (B = 0.1015, SE = 0.0422, Z = 2.4052; B = 0.0634, SE = 0.0343, Z = 1.8484) significantly mediated the effects of catastrophizing on child self-report and parent-report functional disability, respectively, while anxiety (B = - 0.0260, SE = 0.0439501, Z = - 0.5923; B = - 0.0637, SE = 0.0552, Z = - 1.1540) did not. Theoretical and clinical applications are discussed.

Antimicrobial therapies for prevention of recurrent acute exacerbations of COPD (AECOPD): beyond the guidelines

Background

Unfortunately, many COPD patients continue to exacerbate despite good adherence to GOLD Class D recommended therapy. Acute exacerbations lead to an increase in symptoms, decline in lung function and increased mortality rate. The purpose of this review is to do a literature search for any prophylactic anti-microbial treatment trials in GOLD class D patients who ‘failed’ recommended therapy and discuss the role of COPD phenotypes, lung and gut microbiota and co-morbidities in developing a tailored approach to anti-microbial therapies for high frequency exacerbators.

Main text

There is a paucity of large, well-conducted studies in the published literature to date. Factors such as single-centre, study design, lack of well-defined controls, insufficient patient numbers enrolled and short follow-up periods were significant limiting factors in numerous studies. One placebo-controlled study involving more than 1000 patients, who had 2 or more moderate exacerbations in the previous year, demonstrated a non-significant reduction in exacerbations of 19% with 5 day course of moxifloxacillin repeated at 8 week intervals. In Pseudomonas aeruginosa (Pa) colonised COPD patients, inhaled antimicrobial therapy using tobramycin, colistin and gentamicin resulted in significant reductions in exacerbation frequency. Viruses were found to frequently cause acute exacerbations in COPD (AECOPD), either as the primary infecting agent or as a co-factor. However, other, than the influenza vaccination, there were no trials of anti-viral therapies that resulted in a positive effect on reducing AECOPD. Identifying clinical phenotypes and co-existing conditions that impact on exacerbation frequency and severity is essential to provide individualised treatment with targeted therapies. The role of the lung and gut microbiome is increasingly recognised and identification of pathogenic bacteria will likely play an important role in personalised antimicrobial therapies.

Conclusion

Antimicrobial therapeutic options in patients who continue to exacerbate despite adherence to guidelines-directed therapy are limited. Phenotyping patients, identification of co-existing conditions and assessment of the microbiome is key to individualising antimicrobial therapy. Given the impact of viruses on AECOPD, anti-viral therapeutic agents and targeted anti-viral vaccinations should be the focus of future research studies.

Assessment of Knowledge Regarding Risks and Benefits of the Use of Non-Vitamin K Antagonist Oral Anticoagulants

BACKGROUND

Non-vitamin K antagonist oral anticoagulants (NOAC) have replaced vitamin K antagonist (VKA) oral anticoagulants as the first-line treatment option for stroke prevention in high-risk patients with atrial fibrillation. With VKA therapy, disease and treatment-related knowledge is associated with improved adherence and outcomes. There is concern that due to the lack of need for ongoing visits for laboratory monitoring in patients on NOACs, there is less opportunity for education, leading to poor disease- and treatment-related knowledge in this patient group.

METHODS

One hundred ninety-nine (199) patients presenting to 2 primary care clinics on NOAC therapy were surveyed regarding atrial fibrillation and their knowledge regarding NOACs. Chart review was completed to determine patient characteristics and data obtained was compared with survey results to determine the accuracy of the survey responses.

RESULTS

Patients with a lower degree of NOAC knowledge tended to be older (P < .001), have higher Charlson Comorbidity Index scores (P = .001), use apixaban more often (P = .008), and have been on NOACs for a shorter time period (P = .007).

CONCLUSIONS

There is an opportunity to improve NOAC-related knowledge in patients with atrial fibrillation. When developing educational interventions, patient characteristics associated with poor knowledge should be considered. Based on our results, these are patients who are older, more medically complex, are on apixaban, and have been on NOAC therapy for a shorter duration.

Characterization of trace elements exposure in pregnant women in the United States, NHANES 1999-2016

OBJECTIVE

The objective of the current study is to report on urine, blood and serum metal concentrations to characterize exposures to trace elements and micronutrient levels in both pregnant women and women of child-bearing age in the U.S. National Health and Nutrition Examination Survey (NHANES) years 1999-2016.

METHODS

Urine and blood samples taken from NHANES participants were analyzed for thirteen urine metals, three blood metals, three serum metals, speciated mercury in blood and speciated arsenic in urine. Adjusted and unadjusted least squares geometric means and 95% confidence intervals were calculated for all participants among women aged 15-44 years. Changes in exposure levels over time were also examined. Serum cotinine levels were used to adjust for smoke exposure, as smoking is a source of metal exposure.

RESULTS

Detection rates for four urine metals from the ATSDR Substance Priority List: arsenic, lead, mercury and cadmium were ~83-99% for both pregnant and non-pregnant women of child bearing age. A majority of metal concentrations were higher in pregnant women compared to non-pregnant women. Pregnant women had higher mean urine total arsenic, urine mercury, and urine lead; however, blood lead and mercury were higher in non-pregnant women. Blood lead, cadmium, mercury, as well as urine antimony, cadmium and lead in women of childbearing age decreased over time, while urine cobalt increased over time.

CONCLUSIONS

Pregnant women in the US have been exposed to several trace metals, with observed concentrations for some trace elements decreasing since 1999.