3D collagen type I matrix inhibits the antimigratory effect of doxorubicin

<p>Abstract</p> <p>Background</p> <p>The cell microenvironment, especially extracellular matrix proteins, plays an important role in tumor cell response to chemotherapeutic drugs. The present study was designed to investigate whether this microenvironment can influence the antimigratory effect of an anthracycline drug, doxorubicin, when tumor cells are grown in a matrix of type I collagen, a three-dimensional (3D) context which simulates a natural microenvironment.</p> <p>Methods</p> <p>To this purpose, we studied the migratory parameters, the integrin expression, and the activation state of focal adhesion kinase (FAK) and GTPase RhoA involved in the formation of focal adhesions and cell movement. These parameters were evaluated at non toxic concentrations which did not affect HT1080 cell proliferation.</p> <p>Results</p> <p>We show that while doxorubicin decreased cell migration properties by 70% in conventional two-dimensional (2D) culture, this effect was completely abolished in a 3D one. Regarding the impact of doxorubicin on the focal adhesion complexes, unlike in 2D systems, the data indicated that the drug neither affected β1 integrin expression nor the state of phosphorylation of FAK and RhoA.</p> <p>Conclusion</p> <p>This study suggests the lack of antiinvasive effect of doxorubicin in a 3D environment which is generally considered to better mimic the phenotypic behaviour of cells <it>in vivo</it>. Consistent with the previously shown resistance to the cytotoxic effect in a 3D context, our results highlight the importance of the matrix configuration on the tumor cell response to antiinvasive drugs.</p

Dietary patterns of Indian school‐aged children and associations with markers of chronic disease risk

There is an increasing burden of noncommunicable diseases (NCDs) in India which may be related to changing dietary patterns. We aimed to assess dietary patterns in children since they have time to change unhealthy patterns before NCDs develop. Participants were 665 children, 9–12 years old, born with low birth weight and 77 similarly aged normal birth weight controls. We collected data on sociodemography, anthropometry, body composition, and markers of risk for NCDs: grip strength, long jump, hemoglobin A1c (HbA1c). A food frequency questionnaire was used to collect dietary data from which dietary patterns were derived using principal component analysis (PCA). Fourteen food groups were included in the PCA analysis, resulting in three components: ‘fruits and vegetables’, ‘protein’, and ‘sugar and fat’. Higher socioeconomic status and maternal education were associated with lower adherence to the fruit and vegetable pattern and higher adherence to the protein and sugar and fat patterns. Adherence to the fruits and vegetables pattern was associated with lower height‐for‐age, whereas the fat and sugar pattern was associated with higher indicators of body fat. In linear regression analyses adjusted for age, sex, religion, socioeconomic status, maternal education, and season of data collection, adherence to the ‘fruits and vegetables’ pattern was associated with lower grip strength, shorter long jump, and lower HbA1c. Adherence to the other patterns was not associated with NCD risk factors. Higher consumption of fruits and vegetables, achievable even by poorer families in the cohort, may lower HbA1c, a risk factor for diabetes

Ceruloplasmin Deficiency Reduces Levels of Iron and BDNF in the Cortex and Striatum of Young Mice and Increases Their Vulnerability to Stroke

Ceruloplasmin (Cp) is an essential ferroxidase that plays important roles in cellular iron trafficking. Previous findings suggest that the proper regulation and subcellular localization of iron are very important in brain cell function and viability. Brain iron dyshomeostasis is observed during normal aging, as well as in several neurodegenerative disorders such as Alzheimer's, Parkinson's and Huntington's diseases, coincident with areas more susceptible to insults. Because of their high metabolic demand and electrical excitability, neurons are particularly vulnerable to ischemic injury and death. We therefore set out to look for abnormalities in the brain of young adult mice that lack Cp. We found that iron levels in the striatum and cerebral cortex of these young animals are significantly lower than wild-type (WT) controls. Also mRNA levels of the neurotrophin brain derived neurotrophic factor (BDNF), known for its role in maintenance of cell viability, were decreased in these brain areas. Chelator-mediated depletion of iron in cultured neural cells resulted in reduced BDNF expression by a posttranscriptional mechanism, suggesting a causal link between low brain iron levels and reduced BDNF expression. When the mice were subjected to middle cerebral artery occlusion, a model of focal ischemic stroke, we found increased brain damage in Cp-deficient mice compared to WT controls. Our data indicate that lack of Cp increases neuronal susceptibility to ischemic injury by a mechanism that may involve reduced levels of iron and BDNF

Theodor Thumm. Question 5 des Réflexions Thumiennes. L’Image originelle de l’homme peut-elle être décrite ?

International audienc

Extracellular matrix proteins protect human HT1080 cells against the antimigratory effect of doxorubicin.

International audienceIn solid tumors, the cell microenvironment appears to be a key determinant in the emergence of drug resistance, a major obstacle to the successful use of antitumor drugs. Our aim was to determine whether type I collagen and fibronectin, proteins of the extracellular matrix, were able to influence the antimigratory properties induced by the antitumor drug doxorubicin. These properties were investigated at doxorubicin concentrations of 10 and 20 nM, which do not affect cell proliferation on a 24 h drug exposure. Using videomicroscopy, we found that these subtoxic doses of doxorubicin were sufficient to inhibit individual tumor cell motion on two-dimensional plastic surfaces. Such a drug treatment induced a dramatic disturbance of actin stress fiber formation and of vinculin distribution in 80% of cells. In contrast, on extracellular matrix proteins, cell speed was unaffected by drug and perturbation of both actin network and vinculin distribution was detected in only 50% of cells, suggesting a protective effect of the microenvironment. In addition, the phosphorylation of focal adhesion kinase and GTPase RhoA was less affected by doxorubicin with cells cultured on extracellular matrix proteins. In conclusion, our findings indicate that the cell microenvironment prevents drug-dependent inhibition of cell migration in vitro. They reveal cell locomotion as a key factor of microenvironment-mediated drug resistance. This new concept needs to be exploited in in vitro models to optimize the screening of new antimigratory drugs