Effect of Long-Term Hydroxytyrosol Administration on Body Weight,Fat Mass and Urine Metabolomics: A Randomized Double-Blind Prospective Human Study

Hydroxytyrosol (HT) is a natural antioxidant found in olive products and characterized by well-documented beneficial effects on human health. Several research studies are ongoing that aim to investigate its potency and molecular mechanism of action. The present study aimed to investigate the potential effect of HT on human obesity through a randomized double-blind prospective design. HT in two different doses (15 and 5 mg/day) and a placebo capsule was administered to 29 women with overweight/obesity for six months and their weight and fat mass were monitored at three time points (baseline, 4, 12 and 24 weeks). Statistically significant weight and visceral fat mass loss (%weight loss: p = 0.012, %visceral fat loss: p = 0.006) were observed in the group receiving the maximum HT dosage versus placebo after 4 weeks of the intervention, with attenuation of these findings at 12 and 24 weeks of the study. Urine samples were collected during the intervention and analyzed via liquid chromatography–high-resolution mass spectrometry for untargeted metabolomic purposes and comparisons between study groups were performed. HT administration was safe and well-tolerated. To the best of our knowledge, this is the first human cohort investigating the effects of HT on obesity for a prolonged study period.     

Receptor‐interacting protein (RIP) and Sirtuin‐3 (SIRT3) are on opposite sides of anoikis and tumorigenesis

BACKGROUND:

Regulating cross‐talk between anoikis and survival signaling pathways is crucial to regulating tissue processes and mitigating diseases like cancer. Previously, the authors demonstrated that anoikis activates a signaling pathway involving the CD95/Fas‐mediated signaling pathway that is regulated by receptor‐interacting protein (RIP), a kinase that shuttles between Fas‐mediated cell death and integrin/focal adhesion kinase (FAK)‐mediated survival pathways. Because it is known that sirtuin‐3 (SIRT3), a nicotinamide adenine dinucleotide‐dependent deacetylase, regulates cell survival, metabolism, and tumorigenesis, the authors hypothesized that SIRT3 may engage in cross‐talk with Fas/RIP/integrin/FAK survival‐death pathways in cancer cell systems.

METHODS:

Using immunohistochemical staining, immunoblotting, human tissue microarrays, and overexpression and suppression approaches in vitro and in vivo, the roles of RIP and SIRT3 were examined in oral squamous cell carcinoma (OSCC) anoikis resistance and tumorigenesis.

RESULTS:

RIP and SIRT3 had opposite expression profiles in OSCC cells and tissues. Stable suppression of RIP enhanced SIRT3 levels, whereas stable suppression of SIRT3 did not impact RIP levels in OSCC cells. The authors observed that, as OSCC cells became anoikis‐resistant, they formed multicellular aggregates or oraspheres in suspension conditions, and their expression of SIRT3 increased as their RIP expression decreased. Also, anoikis‐resistant OSCC cells with higher SIRT3 and low RIP expression induced an increased tumor burden and incidence in mice, unlike their adherent OSCC cell counterparts. Furthermore, stable suppression of SIRT3 inhibited anoikis resistance and reduced tumor incidence.

CONCLUSIONS:

The current results indicted that RIP is a likely upstream, negative regulator of SIRT3 in anoikis resistance, and an anoikis‐resistant orasphere phenotype defined by higher SIRT3 and low RIP expression contributes to a more aggressive phenotype in OSCC development. Cancer 2012. © 2012 American Cancer Society.     

Low frequency of H-ras mutations in hepatocellular adenomas and carcinomas and in hepatoblastomas from B6C3F1 mice exposed to oxazepam in the diet

Oxazepam has been the subject of recent toxicological and carcinogenesisstudies because it is a commonly prescribed tranquilizer andhas been shown to cause tumors in rodents. In this study, maleand female B6C3F1 mice receIved 0,125, 2500 or 5000 p.p.m. oxazepamin the diet for up to 2 years. Hepatocellular adenomas and carcinomas,as well as hepatoblastomas, which developed in these mice, wereexamined for the presence of activated ms proto-oncogenes. DNAwas Isolated from 20 or more tumors from each exposure groupand analyzed by oligonudeotide hybridiza tion, single-strandedconformation polymorphism analysis and direct sequencing ofPCR-ampllfied H-ms gene fragments for codon 61 mutations. Thirteenof 37 (35%) hepatocellular adenomas and carcinomas from the125 p.p.m. exposure group had mutations in codon 61, while mutationswere detected in only 2 of 25 or 8% of the liver tumors fromthe 2500 p.p.m. exposure group and none of the 22 tumors fromthe 5000 p.p.m. group. This compares to 63% of 126 historIcalcontrol liver tumors and 55% of 20 liver tumors from unexposedB6C3F1 mice in this study. In addition, 12 hepatoblastomas fromthe two high dose groups were examined for H-ras mutations atcodon 61, but none were detected. No tumor DNAs from any ofthe exposure groups tested had mutations In codons 12, 13 or117 of the H-ras gene or codons 12 or 13 of the K-ras gene,the other known hotspots for ras activation in mouse liver tumors.These results, together with those from the National ToxicologyProgram study showing no evidence of cytotoxicity or genotoxicityby oxazepam, suggest that oxazepam preferentially promotes cellsthat have activating lesions other than ras.