Distribution of exogenous [125I]-3-iodothyronamine in mouse in vivo: relationship with trace amine-associated receptors

3-Iodothyronamine (T1AM) is a novel chemical messenger, structurally related to thyroid hormone, able to interact with G protein-coupled receptors known as trace amine-associated receptors (TAARs). Little is known about the physiological role of T1AM. In this prospective, we synthesized [125I]-T1AM and explored its distribution in mouse after injecting in the tail vein at a physiological concentration (0.3?nM). The expression of the nine TAAR subtypes was evaluated by quantitative real-time PCR. [125I]-T1AM was taken up by each organ. A significant increase in tissue vs blood concentration occurred in gallbladder, stomach, intestine, liver, and kidney. Tissue radioactivity decreased exponentially over time, consistent with biliary and urinary excretion, and after 24?h, 75% of the residual radioactivity was detected in liver, muscle, and adipose tissue. TAARs were expressed only at trace amounts in most of the tissues, the exceptions being TAAR1 in stomach and testis and TAAR8 in intestine, spleen, and testis. Thus, while T1AM has a systemic distribution, TAARs are only expressed in certain tissues suggesting that other high-affinity molecular targets besides TAARs exist.     

Individual and summed effects of high-risk genetic polymorphisms on recurrent cardiovascular events following ischemic heart disease

AimsHigh-risk single nucleotide polymorphisms (SNPs) have been recently identified as risk factors for ischemic heart disease in large epidemiological and genome-wide association studies. However, their influence on prognosis remains uncertain. The aim of the study was to investigate the impact of previously identified SNPs and their joint effects in a genetic score (GS) on Major Adverse Cardiac Events (MACEs).Methods and resultsHigh-throughput genotyping for 48 high-risk SNPs was performed in 498 patients (432 males; 57.4 ± 8.3 years) who were followed-up for 6.9 ± 3.4 years. First MACE-coronary-related death, nonfatal myocardial infarction, or myocardial revascularization- was the endpoint taken into consideration. A GS was obtained by summing the number of significant high-risk alleles associated to MACEs.One-hundred and nineteen patients (24%) had a MACE. The hazard ratio (HR) for SNPs with a significant difference in cumulative survival were: APOC3 -482C > T (HR = 1.7, 95% CI 1.01–3.0), MTHFR (HR = 1.5, 95% CI 1.02–2.2), NADHPH oxidase- p22-PHOX C242T (HR = 1.9, 95% CI 1.2–2.8), PON-2 (HR = 0.2, 95% CI 0.1–0.8), and SELP (HR = 0.6, 95% CI 0.4–0.8). The resulting GS predicted a 25% risk for MACEs per risk allele (HR = 1.25, 95% CI 1.1–1.4, p = 0.001). The highest HR for MACEs was found in patients in the top tertile (HR = 3.0, 95% CI 1.4–6.7, p = 0.0005) of the GS compared with those in the bottom tertile.ConclusionOur findings show that high-risk SNPs may be used to create a useful GS that predicts MACEs in a secondary prevention setting, which in turn allows a better risk stratification.     

Interleukin 28B polymorphism predicts pegylated interferon plus ribavirin treatment outcome in chronic hepatitis C genotype 4

Single nucleotide polymorphisms (SNPs) near the interleukin 28B (IL28B) region are the strongest baseline predictors of a sustained virologic response (SVR) to peg-interferon (PegIFN) and ribavirin (Rbv) in patients with hepatitis C virus (HCV) genotype 1 infection. Whether this holds true for HCV-4 patients too is unknown. The aim was to investigate the predictive power of the rs12979860 IL28B SNP for a response to Peg-IFN and Rbv in HCV-4 patients. All HCV-4 patients consecutively treated between September 2004 and June 2010 with PegIFN and Rbv at two liver centers at the Maggiore Hospital Milan (Italy) underwent TaqMan SNP Genotyping assays for testing rs12979860 genotype. Of 112 treated patients (98 males, 75 of Egyptian descent, 26 with cirrhosis) 103 were included in the final analysis; five discontinued treatment for nonvirologic reasons and four did not consent to genetic testing. Twenty-four (23%) were genotype CC, 65 (63%) CT, and 14 (14%) TT. Overall, 50 (49%) achieved an SVR: 21 (88%) CC patients versus 29 (37%) CT/TT (P < 0.0001). CC patients more often had a rapid virologic response (RVR) than CT/TT patients (12, 50% versus 23, 29%; P = 0.08), while also showing lower relapse rates (0% [0/21] versus 36% [16/45] P = 0.0013). In non-RVR patients, SVR rates were higher in CC than CT/TT patients (9 [75%] versus 13 [23%] P = 0.001). By logistic regression, the IL28B rs12979860 CC genotype was an independent predictor of SVR with an odds ratio of 8.0 (95% confidence interval 2.00-32.01; P = 0.003). CONCLUSION: The IL28B rs12979860 SNP may have an added value in the treatment algorithm of HCV-4 patients because it is the strongest predictor of an SVR to PegIFN/Rbv therapy.     

The sorafenib plus nutlin-3 combination promotes synergistic cytotoxicity in acute myeloid leukemic cells irrespectively of FLT3 and p53 status

Background

Both the multi-kinase inhibitor sorafenib and the small molecule inhibitor of the MDM2/p53 interaction, nutlin-3, used alone, have shown promising anti-leukemic activity in acute myeloid leukemia cells. Thus, in this study we investigated the effect of the combination of sorafenib plus nutlin-3 in acute myeloid leukemia.

Design and Methods

Primary acute myeloid leukemia blasts (n=13) and FLT3^wild-type/p53^wild-type (OCI-AML3), FLT3^mutated/p53^wild-type (MOLM), FLT3^mutated/p53^mutated (MV4-11), FLT3^wild-type/p53^deleted (HL60) or FLT3^wild-type/p53^mutated (NB4) acute myeloid cell lines were exposed to sorafenib, used alone or in association with nutlin-3 at a 1:1 ratio, in a range of clinically achievable concentrations (1-10 μM). Induction of apoptosis and autophagy was evaluated by transmission electron microscopy and by specific flow cytometry analyses. The levels of Mcl-1, p53 and Bak proteins were analyzed by western blotting. Knock-down of Bax and Bak gene expression was performed in transfection experiments with specific short interfering RNA.

Results

The sorafenib+nutlin-3 drug combination exhibits synergistic cytotoxicity in primary acute myeloid leukemia blasts and in acute myeloid leukemia cell lines with maximal cytotoxicity in FLT3^mutated MV4-11 and MOLM, followed by the FLT3^wild-type OCI-AML3, HL60 and NB4 cell lines. The cytotoxic activity of sorafenib+nutlin-3 was characterized by an increase of both apoptosis and autophagy. Moreover, Bax and Bak showed prominent roles in mediating the decrease of cell viability in response to the drug combination in p53^wild-type OCI-AML3 and p53^deleted HL-60 cells, respectively, as demonstrated in transfection experiments performed with specific short interfering RNA.

Conclusions

Our data demonstrate that acute myeloid leukemia cells show a variable but overall good susceptibility to the innovative therapeutic combination of sorafenib+nutlin-3, which differentially involves the pro-apoptotic Bcl-2 family members Bax and Bak in p53^wild-type and p53^deleted cells.Key words: sorafenib, nutlin-3, acute myeloid leukemia, p53, apoptosis, autophagy