Imidazo[1,2-b]pyridazines as inhibitors of DYRK kinases

Selective inhibitors of DYRK1A are of interest for the treatment of cancer, Type 2 diabetes and neurological disorders. Optimization of imidazo [1,2-b]pyridazine fragment 1 through structure-activity relationship exploration and in silico drug design efforts led to the discovery of compound 17 as a potent cellular inhibitor of DYRK1A with selectivity over much of the kinome. The binding mode of compound 17 was elucidated with X-ray crystallography, facilitating the rational design of compound 29, an imidazo [1,2-b]pyridazine with improved kinase selectivity with respect to closely related CLK kinases.

The WHO 2016 diagnostic criteria for Acute Myeloid leukemia with myelodysplasia related changes (AML-MRC) produce a very heterogeneous entity: A retrospective analysis of the FAB subtype RAEB-T

We studied 79 patients with AML-MRC or RAEB-T, who were later reclassified according to the WHO classification. Marrow slides were examined cytomorphologically with regard to dysplasia. Patients were followed up until March 2020. Thirty-one patients underwent allogeneic stem cell transplantation (median survival (ms) 16 months), 14 were treated with induction chemotherapy (ms 8.4 months), 18 received hypomethylating agents (ms 9.2 months), 16 received low dose chemotherapy or best supportive care (ms 2.4 months). Only 30.4 % fulfilled the morphologic WHO criteria. 46.8 % were classified as AML-MRC by an antecedent MDS, 54.4 % of the pts were classified by MDS-related chromosomal abnormalities. 5 % did not fulfill any of the criteria and were entered based on 20-29 % medullary blasts. There was no difference in ms between pts presenting with > 50 % dysplasia as compared to pts with dysplasia between 10 % and 50 % (ms 9.1 vs 9.9 months, p = n.s.) or for pts with antecedent MDS (ms 9.1 vs 8.9 months, p = n.s.). Myelodysplasia-related cytogenetic abnormalities were associated with a worse outcome (ms 8.1 vs 13.5 months, p = 0.026). AML-MRC in its current definition is a heterogenous entity. Dysplasia of ≥ 50 % in ≥ two lineages is not helpful for diagnostics and prognostication and therefore should be deleted in future classifications. We recommend utilizing the WHO guidelines for defining dysplasia (10 % or greater in ≥ 1 of the three myeloid cell lines) assisting in establishing the diagnosis of MDS.

Fragment binding to the Nsp3 macrodomain of SARS-CoV-2 identified through crystallographic screening and computational docking

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) macrodomain within the nonstructural protein 3 counteracts host-mediated antiviral adenosine diphosphate-ribosylation signaling. This enzyme is a promising antiviral target because catalytic mutations render viruses nonpathogenic. Here, we report a massive crystallographic screening and computational docking effort, identifying new chemical matter primarily targeting the active site of the macrodomain. Crystallographic screening of 2533 diverse fragments resulted in 214 unique macrodomain-binders. An additional 60 molecules were selected from docking more than 20 million fragments, of which 20 were crystallographically confirmed. X-ray data collection to ultra-high resolution and at physiological temperature enabled assessment of the conformational heterogeneity around the active site. Several fragment hits were confirmed by solution binding using three biophysical techniques (differential scanning fluorimetry, homogeneous time-resolved fluorescence, and isothermal titration calorimetry). The 234 fragment structures explore a wide range of chemotypes and provide starting points for development of potent SARS-CoV-2 macrodomain inhibitors.

Fragment Binding to the Nsp3 Macrodomain of SARS-CoV-2 Identified Through Crystallographic Screening and Computational Docking

The SARS-CoV-2 macrodomain (Mac1) within the non-structural protein 3 (Nsp3) counteracts host-mediated antiviral ADP-ribosylation signalling. This enzyme is a promising antiviral target because catalytic mutations render viruses non-pathogenic. Here, we report a massive crystallographic screening and computational docking effort, identifying new chemical matter primarily targeting the active site of the macrodomain. Crystallographic screening of diverse fragment libraries resulted in 214 unique macrodomain-binding fragments, out of 2,683 screened. An additional 60 molecules were selected from docking over 20 million fragments, of which 20 were crystallographically confirmed. X-ray data collection to ultra-high resolution and at physiological temperature enabled assessment of the conformational heterogeneity around the active site. Several crystallographic and docking fragment hits were validated for solution binding using three biophysical techniques (DSF, HTRF, ITC). Overall, the 234 fragment structures presented explore a wide range of chemotypes and provide starting points for development of potent SARS-CoV-2 macrodomain inhibitors.

Design and Analysis of the 4-Anilinoquin(az)oline Kinase Inhibition Profiles of GAK/SLK/STK10 Using Quantitative Structure-Activity Relationships

The 4-anilinoquinoline and 4-anilinoquinazoline ring systems have been the focus of significant efforts in prior kinase drug discovery programs, which have led to approved medicines. Broad kinome profiles of these compounds have now been assessed with the advent of advanced screening technologies. These ring systems, while originally designed for specific targets including epidermal growth factor receptor (EGFR), but actually display a number of potent collateral kinase targets, some of which have been associated with negative clinical outcomes. We have designed and synthesized a series of 4-anilinoquin(az)olines in order to better understand the structure-activity relationships of three main collateral kinase targets of quin(az)oline-based kinase inhibitors: cyclin G associated kinase (GAK), STE20-like serine/threonine-protein kinase (SLK) and serine/threonine-protein kinase 10 (STK10). This was achieved through a series of quantitative structure-activity relationship (QSAR) analysis, water mapping of the kinase ATP binding sites and extensive small-molecule X-ray structural analysis.

Modular Synthesis of Di- and Trisubstituted Imidazoles from Ketones and Aldehydes: A Route to Kinase Inhibitors

A one-pot and modular approach to the synthesis of 2,4(5)-disubstituted imidazoles was developed based on ketone oxidation, employing catalytic HBr and DMSO, followed by imidazole condensation with aldehydes. This methodology afforded twenty-nine disubstituted NH-imidazoles (23%–85% yield). A three-step synthesis of 20 kinase inhibitors was achieved by employing this oxidation–condensation protocol, followed by bromination and Suzuki coupling in the imidazole ring to yield trisubstituted NH-imidazoles (23%–69%, three steps). This approach was also employed in the synthesis of known inhibitor GSK3037619A.

C8-substituted pyrido[3,4-d]pyrimidin-4(3H)-ones: Studies towards the identification of potent, cell penetrant Jumonji C domain containing histone lysine demethylase 4 subfamily (KDM4) inhibitors, compound profiling in cell-based target engagement assays

Residues in the histone substrate binding sites that differ between the KDM4 and KDM5 subfamilies were identified. Subsequently, a C8-substituted pyrido[3,4-d]pyrimidin-4(3H)-one series was designed to rationally exploit these residue differences between the histone substrate binding sites in order to improve affinity for the KDM4-subfamily over KDM5-subfamily enzymes. In particular, residues E169 and V313 (KDM4A numbering) were targeted. Additionally, conformational restriction of the flexible pyridopyrimidinone C8-substituent was investigated. These approaches yielded potent and cell-penetrant dual KDM4/5-subfamily inhibitors including 19a (KDM4A and KDM5B Ki = 0.004 and 0.007 μM, respectively). Compound cellular profiling in two orthogonal target engagement assays revealed a significant reduction from biochemical to cell-based activity across multiple analogues; this decrease was shown to be consistent with 2OG competition, and suggests that sub-nanomolar biochemical potency will be required with C8-substituted pyrido[3,4-d]pyrimidin-4(3H)-one compounds to achieve sub-micromolar target inhibition in cells.

SGC-GAK-1: A Chemical Probe for Cyclin G Associated Kinase (GAK)

We describe SGC-GAK-1 (11), a potent, selective, and cell-active inhibitor of cyclin G-associated kinase (GAK), together with a structurally related negative control SGC-GAK-1N (14). 11 was highly selective in an in vitro kinome-wide screen, but cellular engagement assays defined RIPK2 as a collateral target. We identified 18 as a potent RIPK2 inhibitor lacking GAK activity. Together, this chemical probe set can be used to interrogate GAK cellular biology.

WNT Activates the AAK1 Kinase to Promote Clathrin-Mediated Endocytosis of LRP6 and Establish a Negative Feedback Loop

β-Catenin-dependent WNT signal transduction governs development, tissue homeostasis, and a vast array of human diseases. Signal propagation through a WNT-Frizzled/LRP receptor complex requires proteins necessary for clathrin-mediated endocytosis (CME). Paradoxically, CME also negatively regulates WNT signaling through internalization and degradation of the receptor complex. Here, using a gain-of-function screen of the human kinome, we report that the AP2 associated kinase 1 (AAK1), a known CME enhancer, inhibits WNT signaling. Reciprocally, AAK1 genetic silencing or its pharmacological inhibition using a potent and selective inhibitor activates WNT signaling. Mechanistically, we show that AAK1 promotes clearance of LRP6 from the plasma membrane to suppress the WNT pathway. Time-course experiments support a transcription-uncoupled, WNT-driven negative feedback loop; prolonged WNT treatment drives AAK1-dependent phosphorylation of AP2M1, clathrin-coated pit maturation, and endocytosis of LRP6. We propose that, following WNT receptor activation, increased AAK1 function and CME limits WNT signaling longevity.

Smokers Display Reduced Glucocorticoid Sensitivity Prior to Symptomatic Chronic Disease Development

Background

Chronic stress plays a critical role in many of today's diseases and causes of death. Tobacco use reliably increases the likelihood of chronic disease development and premature death. In addition, habitual tobacco use elevates risk of chronic inflammatory diseases, and glucocorticoid therapy is often less effective in smokers compared with nonsmokers. Taken together, smokers may develop glucocorticoid insensitivity, thereby removing the body's greatest anti-inflammatory mechanism.

Purpose

The purpose of this study was to examine glucocorticoid sensitivity among 24 smokers and 24 age-, sex-, and body mass index-matched never smokers who were clinically healthy individuals (i.e., no diagnosis or medication use for chronic diseases and normotensive).

Method

Participants visited the lab after a 12 hr fast, provided a blood sample, and completed a series of psychosocial questionnaires. Smokers continued smoking ad libitum before the lab visit. Group differences in glucocorticoid sensitivity were examined using ANCOVA and repeated with linear mixed model to account for possible dependence among immune outcomes that matching participants on age, sex, and body mass index may have introduced.

Results

Prior to clinical disease onset, smokers' peripheral blood mononuclear cells (PBMCs) exhibited reduced glucocorticoid sensitivity as well as a diminished inflammatory response to lipopolysaccharide compared with never smokers' PBMCs; results were identical regardless of statistical modeling used.

Conclusions

Cigarette smoking, a self-initiated pharmacological chronic stressor, may provide a unique opportunity to examine early wear and tear on physiological functioning that may lead to chronic disease development. Additional research into PBMCs' intracellular changes must be examined as well as repeating this study in a larger, more heterogeneous population.

Synthesis of kinase inhibitors containing a pentafluorosulfanyl moiety

A series of 3-methylidene-1H-indol-2(3H)-ones substituted with a 5- or 6-pentafluorosulfanyl group has been synthesized by a Knoevenagel condensation reaction of SF₅-substituted oxindoles with a range of aldehydes. The resulting products were characterized by X-ray crystallography studies and were tested for biological activity versus a panel of cell lines and protein kinases. Some exhibited single digit nM activity.

Identification and Optimization of 4-Anilinoquinolines as Inhibitors of Cyclin G Associated Kinase

4-Anilinoquinolines were identified as potent and narrow-spectrum inhibitors of the cyclin G associated kinase (GAK), an important regulator of viral and bacterial entry into host cells. Optimization of the 4-anilino group and the 6,7-quinoline substituents produced GAK inhibitors with nanomolar activity, over 50 000-fold selectivity relative to other members of the numb-associated kinase (NAK) subfamily, and a compound (6,7-dimethoxy-N-(3,4,5-trimethoxyphenyl)quinolin-4-amine; 49) with a narrow-spectrum kinome profile. These compounds may be useful tools to explore the therapeutic potential of GAK in prevention of a broad range of infectious and systemic diseases.

Correction: Synthesis of kinase inhibitors containing a pentafluorosulfanyl moiety

Correction for ‘Synthesis of kinase inhibitors containing a pentafluorosulfanyl moiety’ by Supojjanee Sansook et al., Org. Biomol. Chem., 2017, 15, 8655–8660.

Isoform-Selective ATAD2 Chemical Probe with Novel Chemical Structure and Unusual Mode of Action

ATAD2 (ANCCA) is an epigenetic regulator and transcriptional cofactor, whose overexpression has been linked to the progress of various cancer types. Here, we report a DNA-encoded library screen leading to the discovery of BAY-850, a potent and isoform selective inhibitor that specifically induces ATAD2 bromodomain dimerization and prevents interactions with acetylated histones in vitro, as well as with chromatin in cells. These features qualify BAY-850 as a chemical probe to explore ATAD2 biology.

Validation of WHO classification-based Prognostic Scoring System (WPSS) for myelodysplastic syndromes and comparison with the revised International Prognostic Scoring System (IPSS-R). A study of the International Working Group for Prognosis in Myelodysplasia (IWG-PM)

A risk-adapted treatment strategy is mandatory for myelodysplastic syndromes (MDS). We refined the World Health Organization (WHO)-classification-based Prognostic Scoring System (WPSS) by determining the impact of the newer clinical and cytogenetic features, and we compared its prognostic power to that of the revised International Prognostic Scoring System (IPSS-R). A population of 5326 untreated MDS was considered. We analyzed single WPSS parameters and confirmed that the WHO classification and severe anemia provide important prognostic information in MDS. A strong correlation was found between the WPSS including the new cytogenetic risk stratification and WPSS adopting original criteria. We then compared WPSS with the IPSS-R prognostic system. A highly significant correlation was found between the WPSS and IPSS-R risk classifications. Discrepancies did occur among lower-risk patients in whom the number of dysplastic hematopoietic lineages as assessed by morphology did not reflect the severity of peripheral blood cytopenias and/or increased marrow blast count. Moreover, severe anemia has higher prognostic weight in the WPSS versus IPSS-R model. Overall, both systems well represent the prognostic risk of MDS patients defined by WHO morphologic criteria. This study provides relevant in formation for the implementation of risk-adapted strategies in MDS.

LP99: Discovery and Synthesis of the First Selective BRD7/9 Bromodomain Inhibitor

The bromodomain-containing proteins BRD9 and BRD7 are part of the human SWI/SNF chromatin-remodeling complexes BAF and PBAF. To date, no selective inhibitor for BRD7/9 has been reported despite its potential value as a biological tool or as a lead for future therapeutics. The quinolone-fused lactam LP99 is now reported as the first potent and selective inhibitor of the BRD7 and BRD9 bromodomains. Development of LP99 from a fragment hit was expedited through balancing structure-based inhibitor design and biophysical characterization against tractable chemical synthesis: Complexity-building nitro-Mannich/lactamization cascade processes allowed for early structure-activity relationship studies whereas an enantioselective organocatalytic nitro-Mannich reaction enabled the synthesis of the lead scaffold in enantioenriched form and on scale. This epigenetic probe was shown to inhibit the association of BRD7 and BRD9 to acetylated histones in vitro and in cells. Moreover, LP99 was used to demonstrate that BRD7/9 plays a role in regulating pro-inflammatory cytokine secretion.

LP99: Discovery and Synthesis of the First Selective BRD7/9 Bromodomain Inhibitor

The bromodomain‐containing proteins BRD9 and BRD7 are part of the human SWI/SNF chromatin‐remodeling complexes BAF and PBAF. To date, no selective inhibitor for BRD7/9 has been reported despite its potential value as a biological tool or as a lead for future therapeutics. The quinolone‐fused lactam LP99 is now reported as the first potent and selective inhibitor of the BRD7 and BRD9 bromodomains. Development of LP99 from a fragment hit was expedited through balancing structure‐based inhibitor design and biophysical characterization against tractable chemical synthesis: Complexity‐building nitro‐Mannich/lactamization cascade processes allowed for early structure–activity relationship studies whereas an enantioselective organocatalytic nitro‐Mannich reaction enabled the synthesis of the lead scaffold in enantioenriched form and on scale. This epigenetic probe was shown to inhibit the association of BRD7 and BRD9 to acetylated histones in vitro and in cells. Moreover, LP99 was used to demonstrate that BRD7/9 plays a role in regulating pro‐inflammatory cytokine secretion.

Reaction pathways for pyridine adsorption on silicon (0 0 1)

Density functional theory is used to describe the reactions of chemisorption of pyridine on the silicon (0 0 1) surface. Adsorption energies of six relevant structures, and the activation energies between them are reported. We consider in detail the dative to tight-bridge transition for which conflicting results have been reported in the literature, and provide a description of the formation of inter-row chains observed in high-coverage experiments. We demonstrate that the choice of DFT functional has a considerable effect on the relative energetics and of the four DFT functionals considered, we find that the range-separated hybrid ωB97X-D functional with empirical dispersion provides the most consistent description of the experiment data.

Extended survival and reduced risk of AML progression in erythroid-responsive lenalidomide-treated patients with lower-risk del(5q) MDS

Lenalidomide is the approved treatment for patients with red blood cell (RBC) transfusion-dependent lower-risk myelodysplastic syndromes (MDS) and chromosome 5q deletion (del(5q)). We report the long-term outcomes (median follow-up 3.2 years) in patients treated with lenalidomide in the MDS-003 trial. RBC transfusion independence (TI) ≥ 8 weeks was achieved in 97 of 148 treated patients (65.5%), with a median response duration of 2.2 years. Partial or complete cytogenetic response was achieved by 63 of 88 evaluable patients (71.6%). Median overall survival (OS) was longer in patients achieving RBC-TI ≥ 8 weeks (4.3 vs 2.0 years in non-responders; P<0.0001) or cytogenetic response (4.9 vs 3.1 years in non-responders; P=0.010). Time to acute myeloid leukemia (AML) progression was longer in patients achieving RBC-TI ≥ 8 weeks or any cytogenetic response versus non-responders (P=0.001 and P=0.0002, respectively). In a landmark multivariate analysis, RBC-TI ≥ 8 weeks was associated with prolonged OS (P<0.001) and a trend toward reduced relative risk of AML progression (P=0.080). Among these lower-risk MDS patients with del(5q), lenalidomide was associated with prolonged RBC-TI and cytogenetic responses, which were linked to improved OS and reduced risk of AML progression.

Design, synthesis and structure-activity relationships of substituted oxazole-benzamide antibacterial inhibitors of FtsZ

The design, synthesis and structure-activity relationships of a series of oxazole-benzamide inhibitors of the essential bacterial cell division protein FtsZ are described. Compounds had potent anti-staphylococcal activity and inhibited the cytokinesis of the clinically-significant bacterial pathogen Staphylococcus aureus. Selected analogues possessing a 5-halo oxazole also inhibited a strain of S. aureus harbouring the glycine-to-alanine amino acid substitution at residue 196 of FtsZ which conferred resistance to previously reported inhibitors in the series. Substitutions to the pseudo-benzylic carbon of the scaffold improved the pharmacokinetic properties by increasing metabolic stability and provided a mechanism for creating pro-drugs. Combining multiple substitutions based on the findings reported in this study has provided small-molecule inhibitors of FtsZ with enhanced in vitro and in vivo antibacterial efficacy.

Monosomal karyotype in MDS: explaining the poor prognosis?

Monosomal karyotype (MK) is associated with an adverse prognosis in patients in acute myeloid leukemia (AML). This study analyzes the prognostic impact of MK in a cohort of primary, untreated patients with myelodysplastic syndromes (MDS). A total of 431 patients were extracted from an international database. To analyze whether MK is an independent prognostic marker in MDS, cytogenetic and clinical data were explored in uni- and multivariate models regarding overall survival (OS) as well as AML-free survival. In all, 204/431 (47.3%) patients with MK were identified. Regarding OS, MK was prognostically significant in patients with ≤ 4 abnormalities only. In highly complex karyotypes (≥ 5 abnormalities), MK did not separate prognostic subgroups (median OS 4.9 months in MK+ vs 5.6 months in patients without MK, P=0.832). Based on the number of abnormalities, MK-positive karyotypes (MK+) split into different prognostic subgroups (MK+ and 2 abnormalities: OS 13.4 months, MK+ and 3 abnormalities: 8.0 months, MK+ and 4 abnormalities: 7.9 months and MK+ and ≥ 5 abnormalities: 4.9 months; P<0.01). In multivariate analyses, MK was not an independent prognostic factor. Our data support the hypothesis that a high number of complex abnormalities, associated with an instable clone, define the subgroup with the worst prognosis in MDS, independent of MK.

Frequent multiple hepatitis C virus infections among injection drug users in a prison setting

Recent data indicate that multiple hepatitis C virus (HCV) infections (mixed infection, superinfection, and reinfection) are common among injection drug users (IDUs). In this study, we identified and characterized multiple HCV infection episodes among HCV-seronegative IDU prison inmates (n = 488) enrolled in the Hepatitis C Incidence and Transmission Study cohort. Incident HCV infection with detectable HCV RNA was identified in 87 subjects, 48 of whom completed additional follow-up to screen for reinfection or superinfection. All HCV RNA-detectable samples were tested for multiple infection through a series of specifically designed nested reverse-transcription polymerase chain reaction (nRT-PCR) with sequencing and HCV RNA level measurement. Sequencing revealed that 22 of 87 (25.3%) subjects were infected by two or more viruses. Nine (10.3%) subjects were designated as prevalent cases of incident mixed infection, because two distinct HCV strains were detected at the first viremic time point. Fifteen further cases of multiple HCV infection (superinfection or reinfection) were identified, two of which also showed baseline incident mixed infections. The incidence of new HCV infection (superinfection and reinfection) during follow-up was 40/100 person-years (95% confidence interval, 33-44/100 person-years). Spontaneous clearance of viruses from one subtype and persistence of the other subtype after mixed infection was observed in eight subjects. In these subjects, the virus with higher HCV RNA levels superseded the other.

CONCLUSION

This study comprehensively analyzed frequent multiple HCV infections in a high-risk cohort and provides further insight into infection dynamics and immunity after exposure to variant viral strains. The data presented suggest that HCV RNA levels play an important role in viral competition.

Creating an antibacterial with in vivo efficacy: synthesis and characterization of potent inhibitors of the bacterial cell division protein FtsZ with improved pharmaceutical properties

3-Methoxybenzamide (1) is a weak inhibitor of the essential bacterial cell division protein FtsZ. Alkyl derivatives of 1 are potent antistaphylococcal compounds with suboptimal drug-like properties. Exploration of the structure−activity relationships of analogues of these inhibitors led to the identification of potent antistaphylococcal compounds with improved pharmaceutical properties.

Evolving trends in the treatment of low-risk myelodysplastic syndromes: immunomodulation and beyond?9th European Hematology Association Congress Geneva, Switzerland, 10?13 June 2004

The 9th European Hematology Association Congress, held in Geneva, Switzerland, from 10 through 13 June 2004, offered a number of educational programmes that focused on myelodysplastic syndromes (MDS). This report will summarize the material presented at the educational symposium entitled 'Evolving Trends in the Treatment of Low-Risk MDS: Immunomodulation and Beyond'. The overview of the presentations includes a comparative review of the classification systems for MDS; a discussion of treatment strategies and management issues for patients in lower risk disease categories; a description of a novel class of immunomodulators, the IMiDs((R)), and a presentation of updated data from clinical trials of the IMiD compound, lenalidomide, in the treatment of MDS.

Organization of the clinical activity of geriatric oncology: report of a SIOG (International Society of Geriatric Oncology) task force

Management for elderly cancer patients world wide is far from being optimal and few older patients are entering clinical trials. A SIOG Task Force was therefore activated to analyze how the clinical activity of Geriatric Oncology is organized. A structured questionnaire was circulated among the SIOG Members. Fifty eight answers were received. All respondents identified Geriatric Oncology, as an area of specialization, however the organization of the clinical activity was variable. Comprehensive Geriatric Assessment (CGA) was performed in 60% of cases. A Geriatric Oncology Program (GOP) was identified in 21 centers, 85% located in Oncology and 15% in Geriatric Departments. In the majority of GOP scheduled case discussion conferences dedicated to elderly cancer patients took regular place, the composition of the multidisciplinary team involved in the GOP activity included Medical Oncologists, Geriatricians, Nurses, Pharmacists, Social Workers. Fellowships in Geriatric Oncology were present in almost half of GOPs. Over 60% of respondents were willing to recruit patients over 70 years in clinical trials, while the proportion of cases included was only 20%. Enrolment in clinical trials was perceived as more difficult by 52% and much more difficult in 12% of the respondents. In conclusion, a better organization of the clinical activity in Geriatric Oncology allows a better clinical practice and an optimal clinical research. The GOP which can be set up in the oncological as well as in the geriatric environment thought a multidisciplinary coordinator effort. Future plans should also concentrate on divisions, units or departments of Geriatric Oncology.

The Third International Congress on Myeloproliferative and Myelodysplastic Syndromes

This meeting was convened by Richard T. Silver and co-chaired by Jerry L. Spivak. It was held from 27 to 29 October 2005 in Washington, DC. Thirty-one invited speakers from seven different countries participated in the conference, which was attended by more than 300 individuals from 23 countries. As in previous years, a clinical symposium for patients, held the day before the symposium, was sponsored by the Cancer Research and Treatment Fund, Inc., New York, NY 10021. This meeting report provides a summary of the five sessions prepared and highlighted by one of the session chairs. In addition to the formal presentations on the biology, clinical aspects and management of these diverse marrow stem cell disorders, there was considerable interest generated because of the availability of several new agents that have been recently approved. A special luncheon satellite symposium was devoted to the dramatic changes in the therapeutic options for the myelodysplastic syndromes, sponsored by MGI Pharma, Inc. The keynote address was presented by Dr. George Q. Daley from Harvard Medical School and the Children's Hospital Medical Center. He reviewed the molecular steps in the formation of the Philadelphia chromosome and some of the newly described mutations leading to resistance to chemotherapy (see Section 4).

Novel Inhibitors of Bacterial Cytokinesis Identified by a Cell-based Antibiotic Screening Assay

The continuous emergence of antibiotic resistance demands that novel classes of antibiotics continue to be developed. The division machinery of bacteria is an attractive target because it comprises seven or more essential proteins that are conserved almost throughout the bacteria but are absent from humans. We describe the development of a cell-based assay for inhibitors of cell division and its use to isolate a new inhibitor of FtsZ protein, a key player in the division machinery. Biochemical, cytological, and genetic data are presented that demonstrate that FtsZ is the specific target for the compound. We also describe the effects of more potent analogues of the original hit compound that act on important pathogens, again at the level of cell division. The assay and the compounds have the potential to provide novel antibiotics with no pool of pre-existing resistance. They have provided new insight into cytokinesis in bacteria and offer important reagents for further studies of the cell division machinery.

Furanyl-1,3-thiazol-2-yl and benzoxazol-5-yl acetic acid derivatives: novel classes of heparanase inhibitor

Using a furanylthiazole acetic acid as a starting point, a novel series of benzoxazol-5-yl acetic acid derivatives have been identified as heparanase inhibitors. Several compounds possess an IC50 of approximately 200 nM against heparanase, for example, trans 2-[4-[3-(3,4-dichlorophenylamino)-3-oxo-1-propenyl]-2-fluorophenyl]benzoxazol-5-yl acetic acid (16e). Several of the compounds show anti-angiogenic properties. Improvement to the DMPK profile of compounds has provided compounds of potential use in in vivo models.

2,3-Dihydro-1,3-dioxo-1H-isoindole-5-carboxylic acid derivatives: a novel class of small molecule heparanase inhibitors

A novel class of 2,3-dihydro-1,3-dioxo-1H-isoindole-5-carboxylic acids are described as inhibitors of the endo-beta-glucuronidase heparanase. Several of the compounds, for example, 2-[4-propylamino-5-[5-(4-chloro)phenyl-benzoxazol-2-yl]phenyl]-2,3-dihydro-1,3-dioxo-1H-isoindole-5-carboxylic acid (9c), display potent heparanase inhibitory activity (IC(50) 200-500 nM) and have high selectivity (>100-fold) over human beta-glucuronidase. They also show anti-angiogenic effects. Such compounds should serve as useful biological tools and may provide a basis for the design of novel therapeutic agents.

A surrogate marker profile for PML/RAR alpha expressing acute promyelocytic leukemia and the association of immunophenotypic markers with morphologic and molecular subtypes

BACKGROUND

The availability of genotype-specific therapy for PML/RAR alpha(pos) acute promyelocytic leukemia (APL) requires that this disease be precisely diagnosed. Immunophenotypic characteristics heretofore proclaimed as reliably characterizing APL (HLA-DR(low), CD34(low), P-glycoprotein(low) myeloid phenotype) do not differentiate from APL-like immune profiles unassociated with the PML/RAR alpha fusion transcript.

METHODS

To establish a surrogate marker profile for APL, we explored 19 potentially predictive markers compared with differentiated acute myeloid leukemia using the classification tree approach with recursive partitioning.

RESULTS

In a test group of 58 APL patients, the most predictive immune profile was HLA-DR(low), CD11a(low) (alpha(L) subunit of the leukocyte integrin LFA-1), CD18(low) (beta(2) subunit of LFA-1). APL cells always expressed CD117 (c-kit) but lacked the progenitor antigen CD133 and the more mature myeloid antigen, CD11b (alpha(M) leukocyte integrin). This antigen pattern was validated in 90 additional APL patients. M3v APLs (n = 30) had more leukemic promyelocytes expressing the T-cell antigen, CD2 (P < 0.0001) or the stem cell marker, CD34 (P = 0.0003) and demonstrated higher fluorescence intensity for the binding of antibody to the common leukocyte antigen, CD45 (P = 0.0008) than M3 (n = 102). S-form APL (n = 45) had a higher percent of cells expressing CD2 or CD34 (P < 0.0001 for both) or the neural cell adhesion molecule CD56 (P = 0.001) than L-form APL (n = 66).

CONCLUSIONS

PML/RAR alpha(pos) APL cells typically lack leukocyte integrins. HLA-DR(low), CD11a(low), CD18(low) is a reliable surrogate antigen expression profile for PML/RAR alpha(pos) APL, irrespective of morphology and transcript isoform.

The second international congress on myeloproliferative and myelodysplastic syndromes

This meeting was convened by Richard T. Silver, M.D. and co-chaired by Jerry L. Spivak, M.D. It was held from 16 to 18 October 2003 in New York City, New York, USA. Thirty-nine invited speakers from nine different countries participated in the conference. There were more than 350 attendees. There were formal presentations and discussions on biology, clinical aspects, and management of patients with these diverse bone marrow stem cell disorders linked by a variable progression to acute myeloid leukemia. Of considerable interest, a clinical symposium exclusively for patients was held the day preceding the meeting at which John Bennett, Tiziano Barbui, Richard Silver, Jerry Spivak, and Ayalew Tefferi spoke on various topics pertaining to these diseases. This proved to be highly informative to the patients who reported that they enjoyed the program immensely. This was sponsored by the Cancer Research & Treatment Fund, Inc. Representatives of the Myelodysplasia Foundation were also present. This meeting report provides a summary of five different sections prepared by one or more of the session chairs. The keynote address was given by Shahin Rafii (Cornell Medical Center). Most appropriately, this talk focused on the expression and activation of angiogenic factors which play a crucial role in the progression of both myeloproliferative disorders and myelodysplastic syndromes (MDS). Among the known factors, vascular endothelial growth tyrosine kinase receptors (VEGF-R1, R2, and R3) support proliferation, survival, and mobility. Rafii's team has demonstrated that these receptors are expressed on subsets of primary hematopoietic cells as well as leukemic cells. Some leukemic cells express both VEGF-A and VEGF-R2, resulting in the generation of an autocrine loop that supports survival and within the osteoblastic zone translocating these cells to the vascular enriched niche for receipt of molecular instructions required for proliferation and differentiation. A pathologic correlation can be seen in some patients with the identification of abnormal localization of immature precursors (ALIP) in the central portions of the medullary cavity. Misplaced megakaryocytes can release pro-fibrotic factors, including platelet derived growth factors and transforming growth factor-beta. Collectively, these data suggest that chronic disregulation of angiogenic factors alter the microenvironment dislocating marrow stem cells that force both proliferation and differentiation in varying degrees, contributing to these hematological disorders.

Low expression of the myeloid differentiation antigen CD65s, a feature of poorly differentiated AML in older adults: study of 711 patients enrolled in ECOG trials

CD65s appears when the progenitor antigen CD34 disappears, suggesting that this sialylated carbohydrate antigen marks a turning point in normal myeloid differentiation. We characterized acute myeloid leukemia (AML) with low CD65s expression (CD65s(low) AML) in 711 patients entered on seven Eastern Cooperative Oncology Group AML treatment trials (1986-1999). Of those, 198 (28%) qualified as having CD65s(low) AML. Morphologically, CD65s(low) AML was more common in FAB subgroups with minimal differentiation, M0/M1 (P=<0.0001). Early precursor antigens CD34, CD117 and terminal transferase were more frequent in CD65s(low) than CD65s(high) AML (P=<0.0001). Myeloperoxidase was present in fewer CD65s(low) myeloblasts, and the more mature myeloid antigens, CD15 and CD11b, were rarely detected (P=<0.0001). Yet, the two diagnoses did not differ in the distribution of cytogenetic prognostic groups or the occurrence of the multidrug-resistance mediator, P-glycoprotein. CD65s(low) AML patients were significantly older than CD65s(high) cases (P<0.0001). Furthermore, the incidence of CD65s(low) cases increased with age, from 20% in patients under the age of 50 years to 67% in patients older than 80 years (P<0.0001). Overall, complete remission (CR) rate and overall survival were comparable in CD65s(low) and CD65s(high) AML. However, among patients >55 years of age, CD65s(low) AML had a decreased CR rate of 33 vs 44% in CD65s(high) AML (P=0.055). Thus, CD65s(low) AML represents immunophenotypically undifferentiated disease and occurs predominantly in older adults. Although not statistically significant, the observed association between low CD65s expression and decreased CR rate only in patients over the age of 55 is intriguing.

A pediatric approach to the WHO classification of myelodysplastic and myeloproliferative diseases

Myelodysplastic and myeloproliferative disorders are rare in childhood and there is no widely accepted system for their diagnosis and classification. We propose minimal diagnostic criteria and a simple classification scheme which, while based on accepted morphological features and conforming with the recent suggestions of the WHO, allows for the special problems of myelodysplastic diseases in children. The classification recognizes three major diagnostic groups: (1) juvenile myelomonocytic leukemia (JMML), previously named chronic myelomonocytic leukemia (CMML) or juvenile chronic myeloid leukemia (JCML); (2) myeloid leukemia of Down syndrome, a disease with distinct clinical and biological features, encompassing both MDS and AML occurring in Down syndrome; and (3) MDS occurring both de novo and as a complication of previous therapy or pre-existing bone marrow disorder (secondary MDS). The main subtypes of MDS are refractory cytopenia (RC) and refractory anemia with excess of blasts (RAEB). It is suggested retaining the subtype of RAEB-T with 20-30% blasts in the marrow until more data are available. Cytogenetics and serial assessments of the patients are essential adjuncts to morphology both in diagnosis and classification.

Antibody-targeted chemotherapy of older patients with acute myeloid leukemia in first relapse using Mylotarg (gemtuzumab ozogamicin)

We analyzed the safety and efficacy of Mylotarg (gemtuzumab ozogamicin, an antibody-targeted chemotherapy consisting of a humanized anti-CD33 antibody linked to calicheamicin, a potent antitumor antibiotic) in the treatment of 101 patients > or =60 years of age with acute myeloid leukemia (AML) in untreated first relapse in three open-label trials. Mylotarg is administered as a 2-h intravenous infusion at 9 mg/m(2) for two doses with 14 days between doses. The overall remission rate was 28%, with complete remission (CR) in 13% of patients and complete remission with incomplete platelet recovery (CRp) in 15%. Median survival was 5.4 months for all patients and 14.5 months and 11.8 months for patients achieving CR and CRp, respectively. CD33 antigen is present on normal hematopoietic progenitor cells; thus, an expected high incidence of grade 3 or 4 neutropenia (99%) and thrombocytopenia (99%) was observed. The incidences of grade 3 or 4 elevations of bilirubin and hepatic transaminases were 24% and 15%, respectively. There was a low incidence of grade 3 or 4 mucositis (4%) and infections (27%) and no treatment-related cardiotoxicity, cerebellar toxicity, or alopecia. Mylotarg is an effective treatment for older patients with CD33-positive AML in first relapse and has acceptable toxicity.

Social exchange and well-being: is giving better than receiving?

This research examined the effects of giving and receiving assistance on psychological well-being while taking into account other salient dimensions of social support including negative interaction and anticipated support. Structural equation models were evaluated by using data derived from a national probability sample of 1,103 individuals aged 65 years or older. Results indicate that the major dimensions of social support are significantly interrelated, not only directly but also indirectly. Giving and receiving support have both positive and negative consequences on well-being. With reference to the role of reciprocity, the evidence provides some support for the hypothesis of esteem enhancement instead of social exchange and equity theories.

Cancer and aging: why not waltz together?

The burden of cancer is felt disproportionately among the elderly with the majority of cancers occurring in adults over the age of 65. Dr. Bennett briefly examines the implications of this fact, and acknowledges the growing evidence that clinicians are ill equipped to handle the complex management issues of their elderly patients. CA will continue this series on geriatric oncology in future issues.

Social exchange and well-being: is giving better than receiving?

This research examined the effects of giving and receiving assistance on psychological well-being while taking into account other salient dimensions of social support including negative interaction and anticipated support. Structural equation models were evaluated by using data derived from a national probability sample of 1,103 individuals aged 65 years or older. Results indicate that the major dimensions of social support are significantly interrelated, not only directly but also indirectly. Giving and receiving support have both positive and negative consequences on well-being. With reference to the role of reciprocity, the evidence provides some support for the hypothesis of esteem enhancement instead of social exchange and equity theories.