Mice with reduced expression of the telomere-associated protein Ft1 develop p53-sensitive progeroid traits

Human AKTIP and mouse Ft1 are orthologous ubiquitin E2 variant proteins involved in telomere maintenance and DNA replication. AKTIP also interacts with A- and B-type lamins. These features suggest that Ft1 may be implicated in aging regulatory pathways. Here, we show that cells derived from hypomorph Ft1 mutant (Ft1kof/kof ) mice exhibit telomeric defects and that Ft1kof/kof animals develop progeroid traits, including impaired growth, skeletal and skin defects, abnormal heart tissue, and sterility. We also demonstrate a genetic interaction between Ft1 and p53. The analysis of mice carrying mutations in both Ft1 and p53 (Ft1kof/kof ; p53ko/ko and Ft1kof/kof ; p53+/ko ) showed that reduction in p53 rescues the progeroid traits of Ft1 mutants, suggesting that they are at least in part caused by a p53-dependent DNA damage response. Conversely, Ft1 reduction alters lymphomagenesis in p53 mutant mice. These results identify Ft1 as a new player in the aging process and open the way to the analysis of its interactions with other progeria genes using the mouse model

The MOCAST+ Study on a Quantum Gradiometry Satellite Mission with Atomic Clocks

In the past twenty years, satellite gravimetry missions have successfully provided data for the determination of the Earth static gravity field (GOCE) and its temporal variations (GRACE and GRACE-FO). In particular, the possibility to study the evolution in time of Earth masses allows us to monitor global parameters underlying climate changes, water resources, flooding, melting of ice masses and the corresponding global sea level rise, all of which are of paramount importance, providing basic data on, e.g. geodynamics, earthquakes, hydrology or ice sheets changes. Recently, a large interest has developed in novel technologies and quantum sensing, which promise higher sensitivity, drift-free measurements, and higher absolute accuracy for both terrestrial surveys and space missions, giving direct access to more precise long-term measurements. Looking at a time frame beyond the present decade, in the MOCAST+ study (MOnitoring mass variations by Cold Atom Sensors and Time measures) a satellite mission based on an “enhanced” quantum payload is proposed, with cold atom interferometers acting as gravity gradiometers, and atomic clocks for optical frequency measurements, providing observations of differences of the gravitational potential. The main outcomes are the definition of the accuracy level to be expected from this payload and the accuracy level needed to detect and monitor phenomena identified in the Scientific Challenges of the ESA Living Planet Program, in particular Cryosphere, Ocean and Solid Earth. In this paper, the proposed payload, mission profile and preliminary platform design are presented, with end-to-end simulation results and assessment of the impact on geophysical applications

Transcriptional Response of Human Neurospheres to helper-dependent CAV-2 vectors involves the modulation of DNA damage response, microtubule and centromere gene groups

Brain gene transfer using viral vectors will likely become a therapeutic option for several disorders. Helper-dependent (HD) canine adenovirus type 2 vectors (CAV-2) are well suited for this goal. These vectors are poorly immunogenic, efficiently transduce neurons, are retrogradely transported to afferent structures in the brain and lead to long-term transgene expression. CAV-2 vectors are being exploited to unravel behavior, cognition, neural networks, axonal transport and therapy for orphan diseases. With the goal of better understanding and characterizing HD-CAV-2 for brain therapy, we analyzed the transcriptomic modulation induced by HD-CAV-2 in human differentiated neurospheres derived from midbrain progenitors. This 3D model system mimics several aspects of the dynamic nature of human brain. We found that differentiated neurospheres are readily transduced by HDCAV- 2 and that transduction generates two main transcriptional responses: a DNA damage response and alteration of centromeric and microtubule probes. Future investigations on the biochemistry of processes highlighted by probe modulations will help defining the implication of HD-CAV-2 and CAR receptor binding in enchaining these functional pathways. We suggest here that the modulation of DNA damage genes is related to viral DNA, while the alteration of centromeric and microtubule probes is possibly enchained by the interaction of the HD-CAV-2 fibre with CAR

Beyond the Genomic Mutation: Rethinking the Molecular Biomarkers of K-RAS Dependency in Pancreatic Cancers

Oncogenic v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (K-RAS) plays a key role in the development and maintenance of pancreatic ductal adenocarcinoma (PDAC). The targeting of K-RAS would be beneficial to treat tumors whose growth depends on active K-RAS. The analysis of K-RAS genomic mutations is a clinical routine; however, an emerging question is whether the mutational status is able to identify tumors effectively dependent on K-RAS for tailoring targeted therapies. With the emergence of novel K-RAS inhibitors in clinical settings, this question is relevant. Several studies support the notion that the K-RAS mutation is not a sufficient biomarker deciphering the effective dependency of the tumor. Transcriptomic and metabolomic profiles of tumors, while revealing K-RAS signaling complexity and K-RAS-driven molecular pathways crucial for PDAC growth, are opening the opportunity to specifically identify K-RAS-dependent- or K-RAS-independent tumor subtypes by using novel molecular biomarkers. This would help tumor selection aimed at tailoring therapies against K-RAS. In this review, we will present studies about how the K-RAS mutation can also be interpreted in a state of K-RAS dependency, for which it is possible to identify specific K-RAS-driven molecular biomarkers in certain PDAC subtypes, beyond the genomic K-RAS mutational status

Mice with reduced expression of the telomere-associated protein Ft1 develop p53-sensitive progeroid traits

International audienceHuman AKTIP and mouse Ft1 are orthologous ubiquitin E2 variant proteins involved in telomere maintenance and DNA replication. AKTIP also interacts with A- and B-type lamins. These features suggest that Ft1 may be implicated in aging regulatory pathways. Here, we show that cells derived from hypomorph Ft1 mutant (Ft1kof/kof ) mice exhibit telomeric defects and that Ft1kof/kof animals develop progeroid traits, including impaired growth, skeletal and skin defects, abnormal heart tissue, and sterility. We also demonstrate a genetic interaction between Ft1 and p53. The analysis of mice carrying mutations in both Ft1 and p53 (Ft1kof/kof ; p53ko/ko and Ft1kof/kof ; p53+/ko ) showed that reduction in p53 rescues the progeroid traits of Ft1 mutants, suggesting that they are at least in part caused by a p53-dependent DNA damage response. Conversely, Ft1 reduction alters lymphomagenesis in p53 mutant mice. These results identify Ft1 as a new player in the aging process and open the way to the analysis of its interactions with other progeria genes using the mouse model

Predictive Signatures Inform the Effective Repurposing of Decitabine to Treat KRAS-Dependent Pancreatic Ductal Adenocarcinoma

Mutated KRAS protein is a pivotal tumor driver in pancreatic cancer. However, despite comprehensive efforts, effective therapeutics that can target oncogenic KRAS are still under investigation or awaiting clinical approval. Using a specific KRAS-dependent gene signature, we implemented a computer-assisted inspection of a drug-gene network to in silico repurpose drugs that work like inhibitors of oncogenic KRAS. We identified and validated decitabine, an FDA-approved drug, as a potent inhibitor of growth in pancreatic cancer cells and patient-derived xenograft models that showed KRAS dependency. Mechanistically, decitabine efficacy was linked to KRAS-driven dependency on nucleotide metabolism and its ability to specifically impair pyrimidine biosynthesis in KRAS-dependent tumors cells. These findings also showed that gene signatures related to KRAS dependency might be prospectively used to inform on decitabine sensitivity in a selected subset of patients with KRAS-mutated pancreatic cancer. Overall, the repurposing of decitabine emerged as an intriguing option for treating pancreatic tumors that are addicted to mutant KRAS, thus offering opportunities for improving the arsenal of therapeutics for this extremely deadly disease.Significance: Decitabine is a promising drug for cancer cells dependent on RAS signaling

High throughput Genechip analysis of HD-CAV-2 neurospheres.

<p>A) Schematic representation of chip analysis workflow. B) Volcano plots: the gene expression difference between transduced samples and mock samples (fold change) is plotted on the x axis in log2 scale, and p-values are plotted on the y axis (–log10 scale). Upregulated and downregulated probes are indicated in red and green, respectively. All control probes were excluded from this analysis. Values represent the average of the three independent replica experiments. C) Probes modulated by HD-CAV-2 at 2h and 5 days posttransduction. The relative fold change values are indicated; in red, upregulated probes, in green, downregulated, and in grey, probes with unmodified expression with respect to mock.</p

Probes regulated uniquely in 2D or 3D cultured hmNPCs by HD-CAV-2.

<p>A) and B) In silico comparison of transcriptome data obtained from 2D hmNPCs transduced at an MOI of 1000 with HD-CAV-2 with data obtained from HD-CAV-2 neurospheres. A) Comparative analysis revealed that 30 probes were found modulated in 3D hmNPCs transduced with HD-CAV-2 and not in 2D cultures. B) g:Profiler gGOSt was used to classify the probes uniquely modulated in 3D culture conditions by HD-CAV-2. The full list of probes modulated in the groups is detailed on <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0133607#pone.0133607.s002" target="_blank">S2 Table</a>. C) Single gene expression was quantified by Q-PCR in differentiated 2D and 3D neural cells transduced with HD-CAV-2 and mock treated, at 5 days postincubation. Results are the average of two experiments performed in duplicate. The difference between mock and HD-CAV-2 treated 2D cells was significant with p<0.05 for all the analyzed genes and the difference between mock and HD-CAV-2 treated neurospheres was not statistically significant. p-values were calculated by Student t-test.</p

HD-CAV-2 efficiently transduces human neurospheres.

<p>Cultures of differentiated hmNPCs were transduced at an MOI of 1000 vg/cell with HD-HAd, LV, and HD-CAV-2, or mock treated and analyzed 5 days posttransduction. A) Single gene expression of dopaminergic markers quantified by Q-PCR in 3D undifferentiated and differentiated neurospheres. The horizontal line on the graphs corresponds to the average value measured in undifferentiated samples. Results are the average of two experiments performed in duplicate. p-values were calculated by Student t-test, * p<0.05; ** p<0.01; ***p<0.001. B) Representative images of transduced neurospheres. Cells were mounted in DAPI-Vectashield and analyzed with an epifluorescence microscope or confocal microscope as indicated. Scale bars, 200 μm. C) Semi-quantitative RT PCR on RNA extracted from transduced neurospheres. D) Q-PCR quantification of GFP expression performed on transduced neurospheres. Data are expressed as % of HD-CAV-2-samples GFP expression levels. E) Efficiency of transduction on 3D cultures quantified by Q-PCR as compared to 2D cells. Data are expressed as % of values obtained with the same vector on 2D cultures. D) and E) Results are the average of two experiments performed in duplicate. p-values were calculated by Student t-test, ** p<0.01.</p