Are tumor cell lineages solely shaped by mechanical forces?

This paper investigates cell proliferation dynamics in small tumor cell aggregates using an individual-based model (IBM). The simulation model is designed to study the morphology of the cell population and of the cell lineages as well as the impact of the orientation of the division plane on this morphology. Our IBM model is based on the hypothesis that cells are incompressible objects that grow in size and divide once a threshold size is reached, and that newly born cell adhere to the existing cell cluster. We performed comparisons between the simulation model and experimental data by using several statistical indicators. The results suggest that the emergence of particular morphologies can be explained by simple mechanical interactions

Experimental Dosimetry Study of a Miniature RF Applicator Dedicated to the Evaluation of Severe RF Exposure Impact on a 3D Biological Model

International audienceThe impact of RF radiation on the living constitutes a controversial topic, whereas wireless applications continue to grow drastically and our daily environment is surrounded of electromagnetic fields. In order to evaluate the potential impact of RF radiations even with severe RF exposures, it is important to conduct experiments with a very well controlled dosimetry and with calibrated RF exposure systems. In this paper, a miniature RF applicator, which enables to apply controlled electromagnetic fields radiation on micro-tissues, is introduced. An experimental method based on thermal measurements has been developed in such a micro-device to define the Specific Absorption Rate applied to micro-tissues depending on the applied power and the thermal increment in steady state. Due to miniature configuration of the applicator, a large range of SAR may be achieved in moderate thermal conditions

Oxygen Partial Pressure Is a Rate-Limiting Parameter for Cell Proliferation in 3D Spheroids Grown in Physioxic Culture Condition

The in situ oxygen partial pressure in normal and tumor tissues is in the range of a few percent. Therefore, when studying cell growth in 3D culture systems, it is essential to consider how the physiological oxygen concentration, rather than the one in the ambient air, influences the proliferation parameters. Here, we investigated the effect of reducing oxygen partial pressure from 21% to 5% on cell proliferation rate and regionalization in a 3D tumor spheroid model. We found that 5% oxygen concentration strongly inhibited spheroid growth, changed the proliferation gradient and reduced the 50% In Depth Proliferation index (IDP50), compared with culture at 21% oxygen. We then modeled the oxygen partial pressure profiles using the experimental data generated by culturing spheroids in physioxic and normoxic conditions. Although hypoxia occurred at similar depth in spheroids grown in the two conditions, oxygen partial pressure was a major rate-limiting factor with a critical effect on cell proliferation rate and regionalization only in spheroids grown in physioxic condition and not in spheroids grown at atmospheric normoxia. Our findings strengthen the need to consider conducting experiment in physioxic conditions (i.e., tissue normoxia) for proper understanding of cancer cell biology and the evaluation of anticancer drugs in 3D culture systems

Antiproliferative effects on multi-cellular tumor spheroids induced by low-temperature plasma

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Synthesis and evaluation of α-ketotriazoles and α,β-diketotriazoles as inhibitors of Mycobacterium tuberculosis

Two series of α-ketotriazole and α,β-diketotriazole derivatives were synthesized and evaluated for antitubercular and cytotoxic activities. Among them, two α,β-diketotriazole compounds, 6b and 9b, exhibited good activities (minimum inhibitory concentration = 7.6 μM and 6.9 μM, respectively) on Mycobacterium tuberculosis and multi-drug resistant M. tuberculosis strains and presented no cytotoxicity (IC50 > 50 μM) on colorectal cancer HCT116 and normal fibroblast GM637H cell lines. These two compounds represent promising leads for further optimization