Imatinib inhibits the expression of SCO2 and FRATAXIN genes that encode mitochondrial proteins in human Bcr-Abl⁺ leukemia cells.

Imatinib mesylate (IM/Gleevec®), a selective inhibitor of chimeric Bcr-Abl tyrosine kinase, was developed as a first line drug to treat CML and ALL Ph(+) patients. Earlier studies have shown that hemin counteracts the IM-induced cell killing in human K-562 CML cells. In this study, we investigated whether IM disrupts the heme-dependent Cytochrome c Oxidase (COX) Biosynthesis and Assembly Pathway (HDCBAP) in Bcr-Abl(+) and Bcr-Abl(-) cells by affecting the expression of key-genes. Cells were exposed to IM and evaluated at time intervals for cell growth, cell death, expression of various genes by RT-PCR analysis as well as Sco2 mature protein levels by western blot analysis and COX enzymatic activity. IM at 1 µM induced extensive cell growth inhibition and cell death as well as marked suppression of the expression of SCO2 and FRATAXIN (FXN) genes in human K-562 and KU-812 Bcr-Abl(+) CML cells. IM also reduced the protein level of mature Sco2 mitochondrial protein as well as COX activity in these cell lines. However, treatment of human MOLT-4 Bcr-Abl(-) cells with 1µM and even with higher concentrations (4×10(-5)M) of IM neither reduced the expression of SCO2 and FXN genes nor suppressed the protein level of mature Sco2 protein and COX activity. Our findings indicate that SCO2 and FXN genes, involved in HDCBAP, are repressed by IM in human Bcr-Abl(+) CML cells and may represent novel target sites in leukemia therapy.

Association between variants in TCF7L2, CTRB1/2, and GLP-1R genes and response to therapy with glucagon-like peptide-1 receptor agonists.

OBJECTIVES: The factors determining the response to treatment with glucagon-like peptide-1 receptor agonists (GLP-1- RAs) have not been clarified. The present study investigated the association between polymorphisms in TCF7L2, CTRB1/2, and GLP-1 R genes and response to GLP-1 RAs regarding glycemic control and weight loss among Greek patients with type 2 diabetes mellitus (T2DM). METHODS: Patients (n = 191) treated with GLP-1 RAs for at least 6 months were included. Participants were genotyped for TCF7L2 rs7903146 (C>T), CTRB1/2 rs7202877 (T>G) and GLP-1 R rs367543060 (C>T) polymorphisms. Clinical and laboratory parameters were measured before, 3, and 6 months after treatment initiation. The patients were classified into responders and non-responders according to specific criteria. RESULTS: Carriers of at least one rs7903146 'T' allele and rs7202877 'G' allele presented similar glucose control and weight loss response to GLP-1 RAs with the respective homozygous wild-type genotypes [odds ratio (OR): 1.08, 95% confidence interval (CI): 0.5, 2.31, p = 0.85 and OR: 1.35, 95% CI: 0.66, 2.76, p = 0.42; OR: 1.4, 95% CI: 0.56, 3.47, p = 0.47 and OR: 1.28, 95% CI: 0.55, 2.98, p = 0.57, respectively]. Regarding the GLP-1 R polymorphism, all participants were homozygous for the wild-type allele; thus, no comparisons were feasible. Female sex (p = 0.03) and lower baseline weight (p = 0.024) were associated with an improved glycemic and weight loss response, respectively. CONCLUSION: There is no evidence suggesting a role for the variants studied in response to GLP-1 RA therapy in people with T2DM. However, specific demographic and clinical factors may be related to a better response to treatment with these agents.

Clinical and Genetic Predictors of Glycemic Control and Weight Loss Response to Liraglutide in Patients with Type 2 Diabetes.

Background: Evidence suggests a heterogeneous response to therapy with glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in patients with type 2 diabetes mellitus (T2DM). The aim of this study is to identify the genetic and clinical factors that relate to glycemic control and weight loss response to liraglutide among patients with T2DM. Methods: The medical records of 116 adults with T2DM (51% female, mean body mass index 35.4 ± 6.4 kg/m2), who had been on treatment with liraglutide for at least 6 months and were genotyped for CTRB1/2 rs7202877 (T > G) polymorphism, were evaluated. Clinical and laboratory parameters were measured at baseline, 3, and 6 months after initiating liraglutide treatment. The good glycemic response was defined as one of the following: (i) achievement of glycated hemoglobin (HbA1c) < 7% (ii) reduction of the baseline HbA1c by ≥1%, and (iii) maintenance of HbA1c < 7% that a patient already had before switching to liraglutide. Weight loss responders were defined as subjects who lost ≥3% of their baseline weight. Results: Minor allele frequency was 16%. Individuals were classified as glycemic control and weight loss responders (81 (70%) and 77 (66%), respectively). Carriers of the rs7202877 polymorphic allele had similar responses to liraglutide treatment in terms of glycemic control (odds ratio (OR): 1.25, 95% confidence interval (CI): 0.4, 3.8, p = 0.69) and weight loss (OR: 1.12, 95% CI: 0.4, 3.2, p = 0.84). In the multivariable analysis, higher baseline HbA1c (adjusted OR: 1.45, 95% CI: 1.05, 2.1, p = 0.04) and lower baseline weight (adjusted OR: 0.97, 95% CI: 0.94, 0.99, p = 0.01) were associated with better glycemic response to liraglutide, while higher baseline weight was associated with worse weight response (adjusted OR: 0.97, 95% CI: 0.95, 0.99, p = 0.02). Conclusions: Specific patient features can predict glycemic and weight loss response to liraglutide in individuals with T2DM.