Exposure to tungsten particles via inhalation triggers early toxicity marker expression in the rat brain.

OBJECTIVE: Our work is focused on tungsten, considered as an emerging contaminant. Its environmental dispersion is partly due to mining and military activities. Exposure scenario can also be occupational, in areas such as the hard metal industry and specific nuclear facilities. Our study investigated the cerebral effects induced by the inhalation of tungsten particles. METHODS: Inhalation exposure campaigns were carried out at two different concentrations (5 and 80 mg/m3) in single and repeated modes (4 consecutive days) in adult rats within a nose-only inhalation chamber. Processes involved in brain toxicity were investigated 24 h after exposure. RESULTS AND DISCUSSION: Site-specific effects in terms of neuroanatomy and concentration-dependent changes in specific cellular actors were observed. Results obtained in the olfactory bulb suggest a potential early effect on the survival of microglial cells. Depending on the mode of exposure, these cells showed a decrease in density accompanied by an increase in an apoptotic marker. An abnormal phenotype of the nuclei of mature neurons, suggesting neuronal suffering, was also observed in the frontal cortex, and can be linked to the involvement of oxidative stress. The differential effects observed according to exposure patterns could involve two components: local (brain-specific) and/or systemic. Indeed, tungsten, in addition to being found in the lungs and kidneys, was present in the brain of animals exposed to the high concentration. CONCLUSION: Our data question the perceived innocuity of tungsten relative to other metals and raise hypotheses regarding possible adaptive or neurotoxic mechanisms that could ultimately alter neuronal integrity.

Association between progression-free survival and overall survival in women receiving first-line treatment for metastatic breast cancer: evidence from the ESME real-world database.

BACKGROUND: Overall survival (OS) is the gold standard endpoint to assess treatment efficacy in cancer clinical trials. In metastatic breast cancer (mBC), progression-free survival (PFS) is commonly used as an intermediate endpoint. Evidence remains scarce regarding the degree of association between PFS and OS. Our study aimed to describe the individual-level association between real-world PFS (rwPFS) and OS according to first-line treatment in female patients with mBC managed in real-world setting for each BC subtype (defined by status for both hormone-receptor [HR] expression and HER2 protein expression/gene amplification). METHODS: We extracted data from the ESME mBC database (NCT03275311) which gathers deidentified data from consecutive patients managed in 18 French Comprehensive Cancer Centers. Adult women diagnosed with mBC between 2008 and 2017 were included. Endpoints (PFS, OS) were described using the Kaplan-Meier method. Individual-level associations between rwPFS and OS were estimated using the Spearman's correlation coefficient. Analyses were conducted by tumor subtype. RESULTS: 20,033 women were eligible. Median age was 60.0 years. Median follow-up duration was 62.3 months. Median rwPFS ranged from 6.0 months (95% CI 5.8-6.2) for HR-/HER2 - subtype to 13.3 months (36% CI 12.7-14.3) for HR + /HER2 + subtype. Correlation coefficients were highly variable across subtypes and first-line (L1) treatments. Among patients with HR - /HER2 - mBC, correlation coefficients ranged from 0.73 to 0.81, suggesting a strong rwPFS/OS association. For HR + /HER2 + mBC patients, the individual-level associations were weak to strong with coefficients ranging from 0.33 to 0.43 for monotherapy and from 0.67 to 0.78 for combined therapies. CONCLUSIONS: Our study provides comprehensive information on individual-level association between rwPFS and OS for L1 treatments in mBC women managed in real-life practice. Our results could be used as a basis for future research dedicated to surrogate endpoint candidates.

Vascular disrupting activity and the mechanism of action of EHT 6706, a novel anticancer tubulin polymerization inhibitor.

Tumor blood vessels are an important emerging target for anticancer therapy. Here, we characterize the in vitro antiproliferative and antiangiogenic properties of the synthetic small molecule, 7-ethoxy-4-(3,4,5-trimethoxybenzyl)isoquinolin-8-amine dihydrochloride, EHT 6706, a novel microtubule-disrupting agent that targets the colchicine-binding site to inhibit tubulin polymerization. At low nM concentrations, EHT 6706 exhibits highly potent antiproliferative activity on more than 60 human tumor cell lines, even those described as being drug resistant. EHT 6706 also shows strong efficacy as a vascular-disrupting agent, since it prevents endothelial cell tube formation and disrupts pre-established vessels, changes the permeability of endothelial cell monolayers and inhibits endothelial cell migration. Genome-wide transcriptomic analysis of EHT 6706 effects on human endothelial cells shows that the antiangiogenic activity elicits gene deregulations of antiangiogenic pathways. These findings indicate that EHT 6706 is a promising tubulin-binding compound with potentially broad clinical antitumor efficacy.

Structure-activity relationship of isoform selective inhibitors of Rac1/1b GTPase nucleotide binding.

The synthesis of a series of berberine, phenantridine and isoquinoline derivatives was realized to explore their Rho GTPase nucleotide inhibitory activity. The compounds were evaluated in a nucleotide binding competition assay against Rac1, Rac1b, Cdc42 and in a cellular Rac GTPase activation assay. The insertion of 19 AA in the splice variant Rac1b is shown to be sufficient to introduce a conformational difference that allows compounds 4, 21, 22, and 26 to exhibit selective inhibition of Rac 1b over Rac1.

RAC1 inhibition targets amyloid precursor protein processing by gamma-secretase and decreases Abeta production in vitro and in vivo.

beta-Amyloid peptides (Abeta) that form the senile plaques of Alzheimer disease consist mainly of 40- and 42-amino acid (Abeta 40 and Abeta 42) peptides generated from the cleavage of the amyloid precursor protein (APP). Generation of Abeta involves beta-secretase and gamma-secretase activities and is regulated by membrane trafficking of the proteins involved in Abeta production. Here we describe a new small molecule, EHT 1864, which blocks the Rac1 signaling pathways. In vitro, EHT 1864 blocks Abeta 40 and Abeta 42 production but does not impact sAPPalpha levels and does not inhibit beta-secretase. Rather, EHT 1864 modulates APP processing at the level of gamma-secretase to prevent Abeta 40 and Abeta 42 generation. This effect does not result from a direct inhibition of the gamma-secretase activity and is specific for APP cleavage, since EHT 1864 does not affect Notch cleavage. In vivo, EHT 1864 significantly reduces Abeta 40 and Abeta 42 levels in guinea pig brains at a threshold that is compatible with delaying plaque accumulation and/or clearing the existing plaque in brain. EHT 1864 is the first derivative of a new chemical series that consists of candidates for inhibiting Abeta formation in the brain of AD patients. Our findings represent the first pharmacological validation of Rac1 signaling as a target for developing novel therapies for Alzheimer disease.

[Cost of treatment and follow up of breast cancer: a retrospective assessment in a comprehensive cancer centre]. / Evaluation rétrospective du coût du cancer du sein dans un centre de lutte contre le cancer.

CONTEXT: Breast cancer is one of the major causes of premature death for women. Its cost management is important for both the national health insurance and the individual health care providers. OBJECTIVE: The objective of this study was to assess the global medical cost of breast cancer from diagnosis to follow up in one French medical centre: centre René-Huguenin, Saint-Cloud (92). METHOD: Duration of medical activities and other medical resources utilisations were collected from a retrospective cohort of 120 patients followed from January 1995 to February 2000. Unit costs were obtained from cost accounts of the Centre. RESULTS: The mean medical cost per patient was FF 66,067 [60,318-7,815] (USD $ 10,744 [9,809-11,679]). The mean cost varied from FF 41,875 (UDS $ 6,810) to FF 81,020 (UDS $ 13,175) depending on choice of type of therapy. The initial treatment phase was the most expensive, costing FF 48,397 [46,176-50,617] (USD $ 7,870 [7,509-8,231]) which represented 73.3% of the global cost. CONCLUSION: This study has provided an estimate of the real global cost of managing patients with breast cancer in a single French Comprehensive Cancer Centre (CLCC). The study method used is readily transposable to other treatment contexts and to other types of cancer.