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Accueil > EN > Research Areas > Complex Systems Dynamics > BIological Systems > Cellular stress response

Oxydative Stress

par Emmanuel COURTADE, François ANQUEZ, Webmestre - publié le , mis à jour le

Oxydative Stress involve Reactive Oxygen Species (ROS) which can have a deleterious effects on DNA, lipids or proteins. Primary ROS (such as anion superoxide or hydrogen peroxyde) induce a rapid ROS amplification cascade leading to the formation of secondary ROS that are damaging macromolecules on the way.

Some primary ROS can be a side product of the cell metabolic activity and cell features protection mecanism implying enzymatic and non-enzymatic anti-oxydants to balance ROS deleterious effect. Oxydative stress can be defined as an imbalance of this redox homeostasis.

It is observed in some pathologies such as neuro-degenrative diseases but it is also use in cancer therapy for the eradication of unwanted cells or tissues (Photo Dynamic Therapy or radiotherapy).

In our early works we have show that singlet oxygen (1O2), a reactive electronic state of molecular oxygen, can be generated in living systems without the need of photo-sensitizing molecule commonly used in Photo-Dynamic Therapy (PDT). Indeed intra-cellular molecular oxygen can be excited via 1270nm laser radiation to induce a oxydative stress and to lead to cell death. While 1270nm direct photo-activation is less efficient than traditional PDT this method has the advantage to induce only 1O2 as a primary ROS.

  • Role of secondary ROS in by stander cell killing

Obviously laser also allows a tightly controlled and localized 1O2 generation. We now want to use pigment-free 1O2 generation to study generation and transport of secondary ROS outside of the targeted cells. Diffusion of secondary ROS could indeed participate the by stander effect. This effect is well known in cancer therapy in wich non-targeted tissues can be destroyed by a localized treatment.

Follow this link to learn more about this project -> here.

A phD student, H. Moulet, is currently working on the project and it is carried in collaboration with our colleagues : V. Senez, A. Treizebre and A. Vlandas from IEMN (Lille, France).

  • Dynamics of ROS scavenging

Obviously laser also allows time varying generation of 1O2. We now use direct photo-activation of 1O2 to probe the kinetics of ROS generation and their scavenging by endogeneous anti-oxidant in living cells. Combined with mathematical modelling, this data should enable us to build a dynamic representation of the first and fast cellular defense against oxydative injury.

Follow this link to learn more about this project -> here.

This work is carried in collaboration with our colleagues theoricists at PhLAM Q. Thommen and B. Pfeuty.

  • Sensitivity of cancer cells vs non cancer cells to oxydative stress : Interplay between oxydative stress and metabolism