Orthogonal IMiD-Degron Pairs Induce Selective Protein Degradation in Cells

Immunomodulatory imide drugs (IMiDs) including thalidomide, lenalidomide, and pomalidomide, can be used to induce degradation of a protein of interest that is fused to a short zinc finger (ZF) degron motif. These IMiDs, however, also induce degradation of endogenous neosubstrates, including IKZF1 and IKZF3. To improve degradation selectivity, we took a bump-and-hole approach to design and screen bumped IMiD analogs against 8380 ZF mutants. This yielded a bumped IMiD analog that induces efficient degradation of a mutant ZF degron, while not affecting other cellular proteins, including IKZF1 and IKZF3. In proof-of-concept studies, this system was applied to induce efficient degradation of TRIM28, a disease-relevant protein with no known small molecule binders. We anticipate that this system will make a valuable addition to the current arsenal of degron systems for use in target validation.

Financial Toxicity and Out-of-Pocket Costs for Patients with Head and Neck Cancer: An Australian Perspective

PURPOSE/OBJECTIVE(S)

Financial toxicity is under-investigated for patients with head and neck cancer (HNC). The aim of this study was to quantify and describe the financial toxicity and out-of-pocket costs for patients with HNC in regional Australia and to consider its relationship with quality of life.

MATERIALS/METHODS

A cross-sectional survey was administered to patients with mucosal HNC who were disease free and 1-3 years after completion of radiotherapy at a regional tertiary hospital in Australia. The survey included questions on socio-demographics, out-of-pocket expenses, and health-related quality of life (HRQoL) measured with the FACT-H&N. Financial toxicity was evaluated using the Financial Index of Toxicity (FIT) survey, which scores financial toxicity on a scale of 0-100 (higher score indicating higher financial toxicity). The relationship between high financial toxicity scores (top quartile) and HRQoL was explored.

RESULTS

Of 57 total patients, 41 (72%) reported out-of-pocket expenses at a median of AU$1,796 (interquartile range AU$2,700) and a maximum of AU$25,050. The overall median FIT score was 13.9 (interquartile range 19.5) and patients with high financial toxicity (n = 14) reported poorer HRQoL (76.5 vs 114.5, p < 0.001). Patients who were not married had a higher financial toxicity score (23.1 vs 11.1, p = 0.01). Similarly, those participants with lower levels of education had higher financial toxicity (19.3 vs 11.1, p = 0.06). Participants with private health insurance were found to have lower rates of financial toxicity (8.3 vs 17.6, p = 0.01). Medications (41%, median AU$400), dietary supplements (41%, median AU$600), travel (36%, median AU$525) and dental (29%, AU$388) were the most common out-of-pocket expenses. Only nineteen patients (33%) reported that a member of their treating team had asked if they have any financial concerns. Participants living in rural locations (> 100km from the hospital) had higher out-of-pocket expenses (AU$2655 vs AU$730, p = 0.01).

CONCLUSION

Financial toxicity is a significant issue for a significant proportion of patients with head and neck cancer which was associated with a reduced HRQoL. All clinicians should consider asking patients with HNC about financial concerns and be aware of what financial support is available in their region. Interventions are required to reduce the burden of financial toxicity for patients with HNC.

On-site treatment of avalanche victims: Scoping review and 2023 recommendations of the international commission for mountain emergency medicine (ICAR MedCom)

INTRODUCTION

The International Commission for Mountain Emergency Medicine (ICAR MedCom) developed updated recommendations for the management of avalanche victims.

METHODS

ICAR MedCom created Population Intervention Comparator Outcome (PICO) questions and conducted a scoping review of the literature. We evaluated and graded the evidence using the American College of Chest Physicians system.

RESULTS

We included 120 studies including original data in the qualitative synthesis. There were 45 retrospective studies (38%), 44 case reports or case series (37%), and 18 prospective studies on volunteers (15%). The main cause of death from avalanche burial was asphyxia (range of all studies 65-100%). Trauma was the second most common cause of death (5-29%). Hypothermia accounted for few deaths (0-4%).

CONCLUSIONS AND RECOMMENDATIONS

For a victim with a burial time ≤ 60 minutes without signs of life, presume asphyxia and provide rescue breaths as soon as possible, regardless of airway patency. For a victim with a burial time > 60 minutes, no signs of life but a patent airway or airway with unknown patency, presume that a primary hypothermic CA has occurred and initiate cardiopulmonary resuscitation (CPR) unless temperature can be measured to rule out hypothermic cardiac arrest. For a victim buried > 60 minutes without signs of life and with an obstructed airway, if core temperature cannot be measured, rescuers can presume asphyxia-induced CA, and should not initiate CPR. If core temperature can be measured, for a victim without signs of life, with a patent airway, and with a core temperature < 30 °C attempt resuscitation, regardless of burial duration.

Discovery of a Novel Bromodomain and Extra Terminal Domain (BET) Protein Inhibitor, I-BET282E, Suitable for Clinical Progression

The functions of the bromodomain and extra terminal (BET) family of proteins have been implicated in a wide range of diseases, particularly in the oncology and immuno-inflammatory areas, and several inhibitors are under investigation in the clinic. To mitigate the risk of attrition of these compounds due to structurally related toxicity findings, additional molecules from distinct chemical series were required. Here we describe the structure- and property-based optimization of the in vivo tool molecule I-BET151 toward I-BET282E, a molecule with properties suitable for progression into clinical studies.

Optimization of a Series of 2,3-Dihydrobenzofurans as Highly Potent, Second Bromodomain (BD2)-Selective, Bromo and Extra-Terminal Domain (BET) Inhibitors

Herein, a series of 2,3-dihydrobenzofurans have been developed as highly potent bromo and extra-terminal domain (BET) inhibitors with 1000-fold selectivity for the second bromodomain (BD2) over the first bromodomain (BD1). Investment in the development of two orthogonal synthetic routes delivered inhibitors that were potent and selective but had raised in vitro clearance and suboptimal solubility. Insertion of a quaternary center into the 2,3-dihydrobenzofuran core blocked a key site of metabolism and improved the solubility. This led to the development of inhibitor 71 (GSK852): a potent, 1000-fold-selective, highly soluble compound with good in vivo rat and dog pharmacokinetics.

Fragment-based Scaffold Hopping: Identification of Potent, Selective, and Highly Soluble Bromo and Extra Terminal Domain (BET) Second Bromodomain (BD2) Inhibitors

The profound efficacy of pan-BET inhibitors is well documented, but these epigenetic agents have shown pharmacology-driven toxicity in oncology clinical trials. The opportunity to identify inhibitors with an improved safety profile by selective targeting of a subset of the eight bromodomains of the BET family has triggered extensive medicinal chemistry efforts. In this article, we disclose the identification of potent and selective drug-like pan-BD2 inhibitors such as pyrazole 23 (GSK809) and furan 24 (GSK743) that were derived from the pyrrole fragment 6. We transpose the key learnings from a previous pyridone series (GSK620 2 as a representative example) to this novel class of inhibitors, which are characterized by significantly improved solubility relative to our previous research.

Template-Hopping Approach Leads to Potent, Selective, and Highly Soluble Bromo and Extraterminal Domain (BET) Second Bromodomain (BD2) Inhibitors

A number of reports have recently been published describing the discovery and optimization of bromo and extraterminal inhibitors which are selective for the second bromodomain (BD2); these include our own work toward GSK046 (3) and GSK620 (5). This paper describes our approach to mitigating the genotoxicity risk of GSK046 by replacement of the acetamide functionality with a heterocyclic ring. This was followed by a template-hopping and hybridization approach, guided by structure-based drug design, to incorporate learnings from other BD2-selective series, optimize the vector for the amide region, and explore the ZA cleft, leading to the identification of potent, selective, and bioavailable compounds 28 (GSK452), 39 (GSK737), and 36 (GSK217).

The non-steroidal anti-inflammatory drug salsalate provides safe and effective control of mucositis-unrelated pain during autologous and allogeneic hematopoietic stem cell transplantation

INTRODUCTION

Pain is a serious adverse event which frequently accompanies hematopoietic stem cell transplantation (HSCT). The safety and efficacy of NSAIDS during HSCT is currently unknown. Salsalate is a platelet-sparing NSAID with a favorable toxicity profile compared with other NSAIDS. We report the safety and efficacy of salsalate for different types of pain during SCT.

METHODS

We conducted a retrospective study of SCT recipients empirically treated with salsalate for > 48 h. Pain scores were assessed using the verbal rating scale for pain. A subset analysis of patients who received > 7 days of salsalate during periods of pancytopenia, mucositis, and other end-organ toxicities is included.

RESULTS

Sixty-four patients, 42 auto- and 22 allografts, were identified. Reason for use: vertebral-related pain (30%), musculoskeletal (30%), and cytokine inflammatory pain syndromes (24%). Median dose 1500 mg/day, number of treatment days = 5, started on day+5 post-HSCT. Pain resolved/improved to pain score < 4 in 76% and stable in 15%. Forty-four patients (28-auto and 16 allografts) received > 7-day salsalate. Median WBC and platelet nadir were < 0.1 and 10,000 cells/ml respectively.

EFFICACY

pain was improved or eradicated in 64% and stable in 32%.

TOXICITY

LFT elevation (n = 2), elevated serum creatinine (n = 2), and minor bleed (n = 5-nose, gums, and urine). Salsalate discontinuation (n = 6): ineffective (n = 1), the liver (n = 1), the kidney (n = 1), > 5 platelet transfusions (n = 1), and vomiting (n = 2). There was no treatment related mortality. Salsalate was well tolerated, safe, and beneficial for several different types of pain during HSCT.

Application of Atypical Acetyl-lysine Methyl Mimetics in the Development of Selective Inhibitors of the Bromodomain-Containing Protein 7 (BRD7)/Bromodomain-Containing Protein 9 (BRD9) Bromodomains

Non-BET bromodomain-containing proteins have become attractive targets for the development of novel therapeutics targeting epigenetic pathways. To help facilitate the target validation of this class of proteins, structurally diverse small-molecule ligands and methodologies to produce selective inhibitors in a predictable fashion are in high demand. Herein, we report the development and application of atypical acetyl-lysine (KAc) methyl mimetics to take advantage of the differential stability of conserved water molecules in the bromodomain binding site. Discovery of the n-butyl group as an atypical KAc methyl mimetic allowed generation of 31 (GSK6776) as a soluble, permeable, and selective BRD7/9 inhibitor from a pyridazinone template. The n-butyl group was then used to enhance the bromodomain selectivity of an existing BRD9 inhibitor and to transform pan-bromodomain inhibitors into BRD7/9 selective compounds. Finally, a solvent-exposed vector was defined from the pyridazinone template to enable bifunctional molecule synthesis, and affinity enrichment chemoproteomic experiments were used to confirm several of the endogenous protein partners of BRD7 and BRD9, which form part of the chromatin remodeling PBAF and BAF complexes, respectively.

Investigating the efficacy of a proposed marine protected area for the Endangered humphead wrasse Cheilinus undulatus at a remote island group in Seychelles

The humphead wrasse Cheilinus undulatus is an iconic, ecologically important and Endangered fish species associated with coral reefs in the Indo-Pacific region. Due to its large size and complex life history characteristics, it is vulnerable to overfishing and has undergone substantial population declines in parts of its range. Knowledge of the species’ movement ecology is currently limited to only 2 previous studies, and very little is known about populations in the western Indian Ocean. The present study aimed to use passive acoustic telemetry to investigate the importance of a remote coral reef to a population of humphead wrasse in the Republic of Seychelles, and subsequently assess the efficacy of a proposed marine protected area at this location for protection of the species. Tagged fish (n = 20) exhibited persistent (>500 d) site fidelity, with low dispersal distances (mean ± SD: 6.44 ± 4.0 km) and restricted core activity spaces (50% Brownian bridge kernel utilization density: 0.91 ± 0.61 km2). Additionally, the study site was home to a group of large (total length 97.9 ± 20.6 cm) and currently unexploited humphead wrasse that showed long-term predictable site fidelity and thus could be vulnerable to over-exploitation. The establishment of a proposed no-take marine protected area at the study site would encompass the core home range area of all tagged humphead wrasse and could effectively conserve this stronghold of Endangered fish to ensure the persistence of the species in Seychelles waters.

A contribution to the characterization of the silicate-water interface - Part I: Implication of a new polished sample hydration technique

The analysis of the atomic composition of the interface between tricalcium silicate (C₃S), the main compound of Ordinary Portland Cement, and surrounding solution is still a challenging task. At the same time, that knowledge is of profound importance for describing the basic processes during hydration. By means of Scanning Electron Microscopy (SEM) and Atom Probe Tomography (APT) we combine modern techniques in order to shed light on this topic in the present study. The results of these methods are compared with conduction calorimetry as a standard technique to study the hydration kinetics of cement. The tests were carried out on powders as well as on polished C₃S samples. Results indicate that the progress of hydration is strongly increased when the C₃S is used in the form of polished specimen. First C-S-H phases are detected in the powder 2.2 h after contact with water, on the polished section after 5 min. Besides SEM, the formation of C-S-H phases can be detected by APT, leading to an advantageous atomic resolution compared to EDX analysis. We propose that the use of APT will lead to deeper insights on the hydration progress and on the composition of the sensitive C-S-H phases based on these first results.

Abstract P6-12-01: Can exercise influence survival following breast cancer? Evidence from randomised, controlled trials

Background: The Exercise for Health (EfH) trials were randomized, controlled trials designed to evaluate an 8-month pragmatic, exercise intervention, commencing 6 weeks post-surgery for women with newly diagnosed breast cancer residing in urban- or rural/regional areas. Outcomes for these exploratory analyses were overall survival (OS), breast cancer-specific survival (BCS) and disease-free survival (DFS). Methods: Consenting urban-residing women (EfH 1, n=194) and rural/regional-residing women (EfH 2, n=143) were randomized to exercise or usual care. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for OS, BCS and DFS (exercise group, n=207, 65% urban women; usual care group, n=130, 46% urban women), with and without adjustment for prognostic factors including trial (urban/rural), age, body mass index, disease stage and presence of comorbidities. Further exploratory subgroup analyses were also conducted to assess whether effect on OS, BCS and DFS differed according to prognostic variables. Results: After a median follow-up of 8.3 years (IQR: 8.0-8.7 years) there were 11 (5.3%) deaths in the exercise group compared with 15 (11.5%) deaths in the usual care group (Table 1).

Table 1 Overall, breast cancer-specific and disease-free survival events by group allocation. All patientsUsual careExercise n=337n = 130n = 207 n (%)n (%)n (%)Breast cancer-related deaths20 (5.9)10 (7.7)10 (4.8)Non-breast cancer-related deaths6 (1.8)5 (3.8)1 (0.5)Overall survival events26 (7.7)15 (11.5)11 (5.3)Recurrence of breast cancer20 (5.9)8 (6.2)12 (5.8)Alive at follow-up9 (2.7)3 (2.3)6 (4.6)Deceased by follow-up11 (3.3)5 (3.1)6 (4.6)New primary breast cancer13 (3.9)5 (3.8)8 (3.9)Alive at follow-up13 (3.9)5 (3.8)8 (6.2)Deceased by follow-up0 (0.0)0 (0.0)0 (0.0)Disease-free survival events*48 (14.2)23 (17.7)25 (12.1)* Disease-free survival events include recurrence of breast cancer, new primary breast cancers, and all-cause deaths. Note that women who had recurrence and died before follow-up only count once towards disease-free survival events.

HRs for the exercise group were: OS: 0.45, 95% CI=0.20-0.96; p=0.04; BCS: 0.61, 95% CI=0.25-1.46, p=0.26; and DFS: 0.66, 95% CI=0.38-1.17; p=0.16 (adjusted analyses yielded similar results). With the exception of BCS for those with a body mass index &gt;30, all HRs for subgroup analyses favored exercise, with effect on OS for women of younger age (&lt;55), those with stage II+ disease, and those with 1+ comorbidity at baseline significant (p&lt;0.05). Effect of exercise on DFS was also significant (p&lt;0.05) for urban women. Conclusion: Findings suggest that an individually-prescribed and monitored exercise program integrated during and beyond treatment for breast cancer, and that was designed to cater for all women, irrespective of place of residence and access to health services, has clear potential to influence survival.

Citation Format: Hayes SC, Steele M, Spence R, Gordon L, Battistutta D, Bashford J, Pyke C, Saunders C, Eakin E. Can exercise influence survival following breast cancer? Evidence from randomised, controlled trials [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-12-01.

Exercise following breast cancer: exploratory survival analyses of two randomised, controlled trials

PURPOSE

The Exercise for Health trials were randomised, controlled trials designed to evaluate an 8-month pragmatic exercise intervention, commencing 6 weeks post-surgery for women with newly diagnosed breast cancer residing in urban or rural/regional Australia. For these exploratory analyses, the primary and secondary outcomes were overall survival (OS) and disease-free survival (DFS), respectively.

METHODS

Consenting urban- (n = 194) and rural/regional-residing women (n = 143) were randomised to exercise (intervention delivered face-to-face or by telephone) or usual care. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CI) for survival outcomes (exercise group, n = 207, 65% urban women; usual care group, n = 130, 46% urban women).

RESULTS

After a median follow-up of 8.3 years, there were 11 (5.3%) deaths in the exercise group compared with 15 (11.5%) deaths in the usual care group (OS HR for the exercise group: 0.45, 95% CI 0.20-0.96; p = 0.04). DFS events for the exercise versus usual care group were 25 (12.1%) and 23 (17.7%), respectively (HR: 0.66, 95% CI 0.38-1.17; p = 0.16). HRs for OS favoured exercise irrespective of age, body mass index, stage of disease, intervention compliance, and physical activity levels at 12 months post-diagnosis, although were stronger (p < 0.05) for younger women, women with stage II + disease, women with 1 + comorbidity at time of diagnosis, higher intervention compliance and for those who met national physical activity guidelines at 12 months post-diagnosis.

CONCLUSION

An exercise intervention delivered during and beyond treatment for breast cancer, and that was designed to cater for all women irrespective of place of residence and access to health services, has clear potential to benefit survival. Trial numbers: ACT RN: 012606000233527; ACT RN: 12609000809235.

Cell Penetrant Inhibitors of the KDM4 and KDM5 Families of Histone Lysine Demethylases. 1. 3-Amino-4-pyridine Carboxylate Derivatives

Optimization of KDM6B (JMJD3) HTS hit 12 led to the identification of 3-((furan-2-ylmethyl)amino)pyridine-4-carboxylic acid 34 and 3-(((3-methylthiophen-2-yl)methyl)amino)pyridine-4-carboxylic acid 39 that are inhibitors of the KDM4 (JMJD2) family of histone lysine demethylases. Compounds 34 and 39 possess activity, IC50 ≤ 100 nM, in KDM4 family biochemical (RFMS) assays with ≥ 50-fold selectivity against KDM6B and activity in a mechanistic KDM4C cell imaging assay (IC50 = 6-8 μM). Compounds 34 and 39 are also potent inhibitors of KDM5C (JARID1C) (RFMS IC50 = 100-125 nM).

Discovery of I-BRD9, a Selective Cell Active Chemical Probe for Bromodomain Containing Protein 9 Inhibition

Acetylation of histone lysine residues is one of the most well-studied post-translational modifications of chromatin, selectively recognized by bromodomain "reader" modules. Inhibitors of the bromodomain and extra terminal domain (BET) family of bromodomains have shown profound anticancer and anti-inflammatory properties, generating much interest in targeting other bromodomain-containing proteins for disease treatment. Herein, we report the discovery of I-BRD9, the first selective cellular chemical probe for bromodomain-containing protein 9 (BRD9). I-BRD9 was identified through structure-based design, leading to greater than 700-fold selectivity over the BET family and 200-fold over the highly homologous bromodomain-containing protein 7 (BRD7). I-BRD9 was used to identify genes regulated by BRD9 in Kasumi-1 cells involved in oncology and immune response pathways and to the best of our knowledge, represents the first selective tool compound available to elucidate the cellular phenotype of BRD9 bromodomain inhibition.

The structure based design of dual HDAC/BET inhibitors as novel epigenetic probes

DUAL946 (1) inhibits BET and HDAC proteins in chemoproteomic cell lysate experiments and in immune and cancer cells.

Comparison of a multifilament stainless steel suture with FiberWire for flexor tendon repairs--an in vitro biomechanical study

Our goal was to investigate and compare the mechanical properties of multifilament stainless steel suture (MFSS) and polyethylene multi-filament core FiberWire in flexor tendon repairs. Flexor digitorum profundus tendons were repaired in human cadaver hands with either a 4-strand cruciate cross-lock repair or 6-strand modified Savage repair using 4-0 and 3-0 multifilament stainless steel or FiberWire. The multifilament stainless steel repairs were as strong as those performed with FiberWire in terms of ultimate load and load at 2 mm gap. This study suggests that MFSS provides as strong a repair as FiberWire. The mode of failure of the MFSS occurred by the suture pulling through the tendon, which suggests an advantage in terms of suture strength.

Configuration of a high-content imaging platform for hit identification and pharmacological assessment of JMJD3 demethylase enzyme inhibitors

The biological complexity associated with the regulation of histone demethylases makes it desirable to configure a cellular mechanistic assay format that simultaneously encompasses as many of the relevant cellular processes as possible. In this report, the authors describe the configuration of a JMJD3 high-content cellular mechanistic imaging assay that uses single-cell multiparameter measurements to accurately assess cellular viability and the enzyme-dependent demethylation of the H3K27(Me)3 mark by exogenously expressed JMJD3. This approach couples robust statistical analyses with the spatial resolving power of cellular imaging. This enables segregation of expressing and nonexpressing cells into discrete subpopulations and consequently pharmacological quantification of compounds of interest in the expressing population at varying JMJD3 expression levels. Moreover, the authors demonstrate the utility of this hit identification strategy through the successful prosecution of a medium-throughput focused campaign of an 87 500-compound file, which has enabled the identification of JMJD3 cellular-active chemotypes. This study represents the first report of a demethylase high-content imaging assay with the ability to capture a repertoire of pharmacological tools, which are likely both to inform our mechanistic understanding of how JMJD3 is modulated and, more important, to contribute to the identification of novel therapeutic modalities for this demethylase enzyme.

Serum creatine kinase and lactate dehydrogenase activities in patients with thyroid disorders

BACKGROUND AND OBJECTIVES

There is the recognition of a pattern of elevations of serum enzymes in hyperthyroid and hypothyroid patients. The aims of this study were to determine the activities of serum creatine kinase (CK) and lactate deydrogenase (LDH) in thyroid disorders, and to evaluate the relationship between CK, LDH and FT4, and TSH levels.

MATERIALS AND METHODS

In this retrospective study, thyroid function tests, serum CK and LDH activities were obtained from the medical records of newly diagnosed hyperthyroid and hypothyroid patients attending the Endocrinology Clinic at the University Hospital of the West Indies from 2005- 2009.

RESULTS

Elevation of CK activity was found in 5 patients (28%, 5/18) with overt hypothyroidism and in 12 patients (24.0%, 12/50) with subclinical hypothyroidism. The mean CK activity in subclinical hypothyroid patients was 179.80 ± 125.68 U/L compared with 389.901 ± 381.20 U/L in overt hypothyroid patients. The elevation of LDH activity was found in 6 patients (33.3%, 6/18) with overt hypothyroidism and in 37 patients (74.0%, 37/50) with subclinical hypothyroidism. In the hypothyroid patients, a positive correlation was found between CK activity and TSH (r = 0.292, P = 0.015), and a negative correlation between CK activity and FT4 (r = - 0.325, P = 0.007); and between FT4 and TSH (r = - 0.371, P = 0.002).

CONCLUSION

The significant elevation in serum CK and LDH activities indicates that these can be used as parameters for screening hypothyroid patients but not hyperthyroid patients.

Fragment-based discovery of bromodomain inhibitors part 2: optimization of phenylisoxazole sulfonamides

Bromodomains are epigenetic reader modules that regulate gene transcription through their recognition of acetyl-lysine modified histone tails. Inhibitors of this protein-protein interaction have the potential to modulate multiple diseases as demonstrated by the profound anti-inflammatory and antiproliferative effects of a recently disclosed class of BET compounds. While these compounds were discovered using phenotypic assays, here we present a highly efficient alternative approach to find new chemical templates, exploiting the abundant structural knowledge that exists for this target class. A phenyl dimethyl isoxazole chemotype resulting from a focused fragment screen has been rapidly optimized through structure-based design, leading to a sulfonamide series showing anti-inflammatory activity in cellular assays. This proof-of-principle experiment demonstrates the tractability of the BET family and bromodomain target class to fragment-based hit discovery and structure-based lead optimization.