A large-scale RNAi screen identifies LCMR1 as a critical regulator of Tspan8-mediated melanoma invasion.

This corrects the article DOI: 10.1038/onc.2016.219.

p53 targets TSPAN8 to prevent invasion in melanoma cells.

Cutaneous melanoma is a very deadly cancer because of its proclivity to metastasize. Despite the recent development of targeted and immune therapies, patient survival remains low. It is therefore crucial to enhance understanding of the molecular mechanisms underlying invasion. We previously identified tetraspanin 8 (TSPAN8) as an important modulator of melanoma invasiveness, and several of its transcriptional regulators, which affect TSPAN8 expression during melanoma progression toward an invasive stage. This study found that TSPAN8 promoter contains consensus-binding sites for p53 transcription factor. We demonstrated that p53 silencing was sufficient to turn on Tspan8 expression in non-invasive melanoma cells and that p53 acts as a direct transcriptional repressor of TSPAN8. We also showed that p53 modulated matrigel invasion in melanoma cells in a TSPAN8-dependent manner. In conclusion, this study reveals p53 as a negative regulator of Tspan8 expression. As TP53 gene is rarely mutated in melanoma, it was hitherto poorly studied but its role in apoptosis and growth suppression in melanoma is increasingly becoming clear. The study highlights the importance of p53 as a regulator of melanoma invasion and the concept that reactivating p53 could provide a strategy for modulating not only proliferative but also invasive capacity in melanoma treatment.

A large-scale RNAi screen identifies LCMR1 as a critical regulator of Tspan8-mediated melanoma invasion.

Melanoma is the deadliest form of skin cancer owing to its proclivity to metastasise, and recently developed therapies have not yielded the expected results, because almost all patients relapse. Therefore, understanding the molecular mechanisms that underlie early invasion by melanoma cells is crucial to improving patient survival. We have previously shown that, whereas the Tetraspanin 8 protein (Tspan8) is undetectable in normal skin and benign lesions, its expression arises with the progression of melanoma and is sufficient to increase cell invasiveness. Therefore, to identify Tspan8 transcriptional regulators that could explain the onset of Tspan8 expression, thereby conferring an invasive phenotype, we performed an innovative RNA interference-based screen, which, for the first time, identified several Tspan8 repressors and activators, such as GSK3ß, PTEN, IQGAP1, TPT1 and LCMR1. LCMR1 is a recently identified protein that is overexpressed in numerous carcinomas; its expression and role, however, had not previously been studied in melanoma. The present study identified Tspan8 as the first LCMR1 target that could explain its function in carcinogenesis. LCMR1 modulation was sufficient to positively regulate endogenous Tspan8 expression, with concomitant in vitro phenotypic changes such as loss of melanoma cell-matrix adherence and increase in invasion, and Tspan8 expression promoted tumourigenicity in vivo. Moreover, LCMR1 and Tspan8 overexpression were shown to correlate in melanoma lesions, and both proteins could be downregulated in vitro by vemurafenib. In conclusion, this study highlights the importance of Tspan8 and its regulators in the control of early melanoma invasion and suggests that they may be promising new therapeutic targets downstream of the RAF-MEK-ERK signalling pathway.

Functional interplay between p63 and p53 controls RUNX1 function in the transition from proliferation to differentiation in human keratinocytes.

The interfollicular epidermis is continuously renewed, thanks to a regulated balance between proliferation and differentiation. The ΔNp63 transcription factor has a key role in the control of this process. It has been shown that ΔNp63 directly regulates Runt-related transcription factor 1 (RUNX1) transcription factor expression in mouse keratinocytes. The present study showed for the first time that RUNX1 is expressed in normal human interfollicular epidermis and that its expression is tightly regulated during the transition from proliferation to differentiation. It demonstrated that ΔNp63 directly binds two different RUNX1 regulatory DNA sequences and modulates RUNX1 expression differentially in proliferative or differentiated human keratinocytes. It also showed that the regulation of RUNX1 expression by ΔNp63 is dependent on p53 and that this coregulation relies on differential binding and activation of RUNX1 regulatory sequences by ΔNp63 and p53. We also found that RUNX1 inhibits keratinocyte proliferation and activates directly the expression of KRT1, a critical actor in early keratinocyte differentiation. Finally, we described that RUNX1 expression, similar to ΔNp63 and p53, was strongly expressed and downregulated in basal cell carcinomas and squamous cell carcinomas respectively. Taken together, these data shed light on the importance of tight control of the functional interplay between ΔNp63 and p53 in regulating RUNX1 transcription factor expression for proper regulation of interfollicular epidermal homeostasis.

Cognitive decline and survival in Alzheimer's disease according to education level.

OBJECTIVE: We tested the hypothesis that a higher education level is associated with faster cognitive decline and lower survival in a cohort of 670 Alzheimer's disease patients, followed for 3.5 years at the Lille-Bailleul memory centre. METHODS: The patients were categorized in 3 groups according to educational levels: low (12 years). Cognitive function was measured with the Mini Mental State Examination (MMSE) and the Mattis Dementia Rating Scale (DRS). Survival was analyzed with a Cox model. Analyses were adjusted for age, sex, cholinesterase inhibitor treatment, diabetes, hypertension, visible vascular lesions on MRI, baseline DRS and MMSE. RESULTS: The adjusted mixed random model showed that MMSE declined faster for patients with high and intermediate educational levels compared with those with a low educational level (p < 0.0001). The mean annually adjusted DRS decline was highest for the groups with the most education (p = 0.05). The mortality risk was not higher in the better-educated groups (high vs. low: RR = 0.84; 95% CI = 0.35-1.99, intermediate vs. low: RR = 0.82; 95% CI = 0.41-1.63). CONCLUSION: In our cohort, highly educated patients had a faster cognitive decline than less educated patients but similar mortality rates. Our findings support the cognitive reserve hypothesis.

Prior TIA, lipid-lowering drug use, and physical activity decrease ischemic stroke severity.

OBJECTIVE: To determine clinical and pharmacologic factors that could influence the initial severity and short-term outcome of cerebral ischemia. METHODS: In a cross-sectional hospital-based study of patients with acute supratentorial ischemic stroke, we systematically collected medical history, previous leisure-time physical activity, current and previous treatments, blood pressure, temperature, blood glucose, fibrinogen, NIH Stroke Scale (NIHSS) score at admission, and outcome at day 8. Factors potentially associated with initial stroke severity and outcome were selected by univariate analyses and then validated in logistic regression analyses with lower severity of stroke at admission (NIHSS 0 to 5) or good outcome at day 8 (modified Rankin Scale 0 to 1, Barthel Index 95 to 100) as dependent variables. RESULTS: In 362 consecutive patients (median age 70 years, range 16 to 97 years; 195 women), independent factors associated with a lower severity at admission were previous leisure-time physical activity (adjusted odds ratio [OR] 1.67, 95% CI 1.07 to 2.66), TIA (adjusted OR 2.28, 95% CI 1.06 to 4.87) and treatment with lipid-lowering drug (adjusted OR 1.76, 95% CI 1.02 to 3.03). Previous treatment with lipid-lowering drug and leisure-time physical activity were also independent factors associated with a good short-term outcome. CONCLUSION: Both regular physical activity and lipid-lowering drugs should be prospectively evaluated to determine whether they reduce the severity of ischemic stroke.

Lipid lowering agents are associated with a slower cognitive decline in Alzheimer's disease.

BACKGROUND: Data from epidemiological studies and animal models imply that disturbances in cholesterol metabolism are linked to Alzheimer's disease susceptibility. Lipid lowering agents (LLAs) may have implications for the prevention of Alzheimer's disease. OBJECTIVE: To investigate whether LLAs are associated with a slower cognitive decline in Alzheimer's disease. METHODS: An observational study in 342 Alzheimer patients followed in a memory clinic for 34.8 months (mean age 73.5 years, mini-mental state examination score (MMSE) 21.3 at entry); 129 were dyslipaemic treated with LLAs (47% with statins), 105 were untreated dyslipaemic, and 108 were normolipaemic. The rate of cognitive decline was calculated as the difference between the first and last MMSE score, divided by the time between the measurements, expressed by year. Patients were divided into slow and fast decliners according to their annual rate of decline (lower or higher than the median annual rate of decline in the total population). RESULTS: Patients treated with LLAs had a slower decline on the MMSE (1.5 point/year, p = 0.0102) than patients with untreated dyslipaemia (2.4 points/year), or normolipaemic patients (2.6 points/year). Patients with a slower decline were more likely to be treated with LLAs. Logistic regression analysis, with low annual cognitive decline as the dependent variable, showed that the independent variable LLA (treated with or not) was positively associated with the probability of lower cognitive decline (odds ratio = 0.45, p = 0.002). CONCLUSIONS: LLAs may slow cognitive decline in Alzheimer's disease and have a neuroprotective effect. This should be confirmed by placebo controlled randomised trials in patients with Alzheimer's disease and no dyslipaemia.

The development of experimental procedures for the evaluation of additives to attenuate manure odour, and the impact of these additives on workers, animals and the environment.

The objective of this project was to develop a laboratory research protocol to evaluate the effect of additives on manure odour and physico-chemical characteristics, and establish conditions that are representative of those found in farm storage structures (temperature, solids content, pH, ventilation above the manure surface, storage period). The results suggested that system configuration might have an impact on additive effect. An open system should be used when it is recommended that additives be applied in the animal diet or the gutters. Additionally, the surface/depth ratio of the gutter should be respected, since it will impact on the relative importance of the aerobic layer and on ammonia volatilization. On the other hand, a closed system should be used when the additive is applied to the manure storage tank, especially if the tank has a cover. Odour analysis still requires fundamental research to establish reliable procedures and protocols, especially in the area sample collection and dilution levels required to decrease H2S concentration to safe levels for the panellists. Odour analysis should also be conducted in triplicate, because of the possible large experimental error due to dilution, the human factors, and also instrumental error.