3 research outputs found
Rock-magnetic properties of topsoils and urban dust from Morelia (>800,000 inhabitants), Mexico: Implications for anthropogenic pollution monitoring in Mexico’s medium size cities
En el presente trabajo, investigamos la correlación
entre algunos parámetros magnéticos y el
nivel de contaminación por metales pesados
en suelos urbanos de la ciudad de Morelia, en
el occidente de México. El estudio magnético
fue llevado a cabo en 98 muestras urbanas
provenientes de diferentes tipos de uso de
suelo. La mayoría de las muestras contienen
minerales ferrimagnéticos como responsables de
la magnetización, pertenecientes probablemente
a las soluciones sólidas de las titanomagnetitas/
titanomaghemitas. Esto es inferido a partir de
las mediciones de susceptibilidad en función
de la temperatura y de los experimentos de
magnetización remanente isotérmica (MRI). Estas
mediciones indican además, que la mayoría de las
muestras se saturan casi completamente antes de
los 300 mT. Adicionalmente, los valores S-200 (S-200
= IRM-200/SIRM, donde IRM-200= magnetización
a campo inverso de 200 mT después de la
saturación magnética) se encuentran entre 0.7
y 1.0, característicos de minerales de baja
coercitividad magnética. Las curvas promedio
de magnetización remanente isotérmica de
saturación (SIRM) pueden ser usadas como un
indicador del nivel de contaminación, ya que estas
curvas muestran diferentes valores de saturación
de acuerdo al nivel de contaminación por metales
pesados: Cu, Ni, Cr y Sr. Estas asociaciones de
(titano)magnetitas con metales pesados fueron
observadas bajo el Microscopio Electrónico de
Barrido, revelando algunos agregados complejos
en lugar de las esférulas detectadas comúnmente.In this work, we investigate the correlation between some magnetic parameters and the level of contamination by heavy metals in urban soils from Morelia city, western Mexico. The magnetic study was carried out on 98 urban soils samples belonging to distinct land uses. Most of analyzed samples contain ferrimagnetic minerals as the responsible for magnetization, most probably corresponding to the titanomagnetites/titanomaghemites solid solutions. This is inferred from the susceptibility vs. temperature
measurements and the isothermal remanent magnetization (IRM) experiments. These measurements also indicate that most of samples are almost completely saturated before 300 mT. Additionally, the S-200 values (S-200 = IRM-200/ SIRM, where IRM-200= Back-field of 200 mT after magnetic saturation) are between 0.7 and 1.0, characteristic of low coercivity magnetic minerals. The averaged saturation isothermal remanent magnetization (SIRM) curves can be used as an indicator of pollution level, as these curves show
different saturation values according to the level of contamination by heavy metals: Cu, Ni, Cr and Sr. These associations of (titano)magnetite with heavy metals were observed by Scanning Electron Microscope revealing some complex aggregates rather than commonly detected spherules.Universidad
Nacional Autónoma de México through the
projects CONACYT 118971 and PAPIIT IN 22311
A Label-Free Cell Sorting Approach to Highlight the Impact of Intratumoral Cellular Heterogeneity and Cancer Stem Cells on Response to Therapies
International audienceCancer stem cells play a crucial role in tumor initiation, metastasis, and resistance to treatment. Cellular heterogeneity and plasticity complicate the isolation of cancer stem cells. The impact of intra-tumor cellular heterogeneity using a label-free approach remains understudied in the context of treatment resistance. Here, we use the sedimentation field-flow fractionation technique to separate, without labeling, cell subpopulations of colorectal cancer cell lines and primary cultures according to their biophysical properties. One of the three sorted cell subpopulations exhibits characteristics of cancer stem cells, including high tumorigenicity in vivo and a higher frequency of tumor-initiating cells compared to the other subpopulations. Due to its chemoresistance, two- and three-dimensional in vitro chemosensitivity assays highlight the therapeutic relevance of this cancer stem cell subpopulation. Thus, our results reveal the major implication of intra-tumor cellular heterogeneity, including cancer stem cells in treatment resistance, thanks to our label-free cell sorting approach. This approach enables-by breaking down the tumor-the study the individualized response of each sorted tumor cell subpopulation and to identify chemoresistance, thus offering new perspectives for personalized therapy
Overexpression of sortilin is associated with 5‐FU resistance and poor prognosis in colorectal cancer
International audienceColorectal cancer (CRC) is the third most common cancer worldwide. Even if 5‐fluorouracil (5‐FU) is used as the first‐line chemotherapeutic drug, responsiveness is only 20‐30%. Acquired resistance to 5‐FU contributes to both poor patient prognosis and relapse, emphasizing the need to identify biomarkers. Sortilin, a vacuolar protein sorting 10 protein (Vps10p), implicated in protein trafficking, is over expressed in CRC cell lines cultured 72 hours in presence of 5‐FU. This overexpression was also observed in 5‐FU‐resistant cells derived from these cell lines as well as in CRC primary cultures (or patients derived cell lines). A significantly higher expression of sortilin was observed in vivo, in 5‐FU‐treated tumours engrafted in Nude mice, as compared with non‐treated tumour. A study of transcriptional regulation allowed identifying a decrease in ATF3 expression, as an explanation of sortilin overexpression following 5‐FU treatment. In silico analysis revealed SORT1 expression correlation with poor prognosis. Moreover, sortilin expression was found to be positively correlated with CRC tumour grades. Collectively, our findings identify sortilin as a potential biomarker of 5‐FU resistance associated with poor clinical outcomes and aggressiveness in CRC. As a new prognostic factor, sortilin expression could be used to fight against CRC