New Inhibitors of Bcr-Abl Based on 2,6,9-Trisubstituted Purine Scaffold Elicit Cytotoxicity in Chronic Myeloid Leukemia-Derived Cell Lines Sensitive and Resistant to TKIs.

Bcr-Abl is an oncoprotein with aberrant tyrosine kinase activity involved in the progression of chronic myeloid leukemia (CML) and has been targeted by inhibitors such as imatinib and nilotinib. However, despite their efficacy in the treatment of CML, a mechanism of resistance to these drugs associated with mutations in the kinase region has emerged. Therefore, in this work, we report the synthesis of 14 new 2,6,9-trisubstituted purines designed from our previous Bcr-Abl inhibitors. Here, we highlight 11b, which showed higher potency against Bcr-Abl (IC50 = 0.015 µM) than imatinib and nilotinib and exerted the most potent antiproliferative properties on three CML cells harboring the Bcr-Abl rearrangement (GI50 = 0.7-1.3 µM). In addition, these purines were able to inhibit the growth of KCL22 cell lines expressing Bcr-AblT315I, Bcr-AblE255K, and Bcr-AblY253H point mutants in micromolar concentrations. Imatinib and nilotinib were ineffective in inhibiting the growth of KCL22 cells expressing Bcr-AblT315I (GI50 > 20 µM) compared to 11b-f (GI50 = 6.4-11.5 µM). Molecular docking studies explained the structure-activity relationship of these purines in Bcr-AblWT and Bcr-AblT315I. Finally, cell cycle cytometry assays and immunodetection showed that 11b arrested the cells in G1 phase, and that 11b downregulated the protein levels downstream of Bcr-Abl in these cells.

The association of a reduced susceptibility to moxifloxacin in causative Clostridium (Clostridioides) difficile strain with the clinical outcome of patients.

OBJECTIVES: To investigate the relationship between Clostridium (Clostridioides) difficile strain characteristics and C. difficile infection (CDI) outcome. METHODS: Between October and December 2017, 16 hospitals collected epidemiological data according to the European Centre for Disease Prevention and Control (ECDC) surveillance protocol for CDI. C. difficile isolates were characterized by ribotyping, toxin genes detection and antibiotic susceptibility testing to metronidazole, vancomycin and moxifloxacin. RESULTS: The overall mean CDI incidence density was 4.5 [95% CI 3.6-5.3] cases per 10,000 patient-days. From the 433 CDI cases, 330 (76.2%) were healthcare-associated, 52 (12.0%) cases were community-associated or of unknown origin and 51 (11.8%) CDI cases recurrent; a complicated course of CDI was reported in 65 cases (15.0%). Eighty-eight (20.3%) of patients died and 59 of them within 30 days after the CDI diagnosis. From the 379 C. difficile isolates, the most prevalent PCR ribotypes were 001 (n = 127, 33.5%) and 176 (n = 44, 11.6%). A total of 186 (49.1%) isolates showed a reduced susceptibility to moxifloxacin (> 4 mg/L) and 96.4% of them had Thr82Ile in the GyrA. Nineteen isolates revealed reduced susceptibility to metronidazole and two isolates to vancomycin (> 2 mg/L). A fatal outcome was associated with a reduced susceptibility to moxifloxacin, the advanced age of the patients and a complicated course of CDI (p<0.05). No association between ribotype, binary toxin and a reduced susceptibility to moxifloxacin and complicated course or recurrent CDI was found. CONCLUSIONS: A reduced susceptibility to moxifloxacin, in causative C. difficile strains was associated with fatal outcome of the patients, therefore it is an important marker in surveillance of CDI.

Cryptic aberrations may allow more accurate prognostic classification of patients with myelodysplastic syndromes and clonal evolution.

The karyotype of bone-marrow cells at the time of diagnosis is one of the most important prognostic factors in patients with myelodysplastic syndromes (MDS). In some cases, the acquisition of additional genetic aberrations (clonal evolution [CE]) associated with clinical progression may occur during the disease. We analyzed a cohort of 469 MDS patients using a combination of molecular cytogenomic methods to identify cryptic aberrations and to assess their potential role in CE. We confirmed CE in 36 (8%) patients. The analysis of bone-marrow samples with a combination of cytogenomic methods at diagnosis and after CE identified 214 chromosomal aberrations. The early genetic changes in the diagnostic samples were frequently MDS specific (17 MDS-specific/57 early changes). Most progression-related aberrations identified after CE were not MDS specific (131 non-MDS-specific/155 progression-related changes). Copy number neutral loss of heterozygosity (CN-LOH) was detected in 19% of patients. MDS-specific CN-LOH (4q, 17p) was identified in three patients, and probably pathogenic homozygous mutations were found in TET2 (4q24) and TP53 (17p13.1) genes. We observed a statistically significant difference in overall survival (OS) between the groups of patients divided according to their diagnostic cytogenomic findings, with worse OS in the group with complex karyotypes (P = .021). A combination of cytogenomic methods allowed us to detect many cryptic genomic changes and identify genes and genomic regions that may represent therapeutic targets in patients with progressive MDS.