Nowadays, a fight against cancer seems to be one of the most important issue for scientists. Research groups all around the world are working on new cancer therapies which target tumour cells. One of the approaches to this problem consists in learning the physiological differences between normal and neoplastic tissue. The differences could appeared among physiological parameters such as redox state, oxygenation and pH value. The fact is that Electron Paramagnetic Resonance is a non-invasive and rapid method that enables detection of insignificant changes of above-mentioned characteristics and thus it is a great tool for preclinical cancer research and has a great potential to become a method used in clinical trials.
A hypothesis that the redox state and pO2 value differ in normal and neoplastic tissue, have been presented in a paper “Noninvasive Imaging of Tumor Redox Status and Its Modification by Tissue Glutathione Levels” by Kuppusamy et al.
The main goal of the research was: i) develop a non-invasive technique that enables measurement and imaging of the tissue’s redox state ii) acquire images of redox state from normal and malignant tissue iii) analyse the role of glutathione (GSH) in changes of the redox status. In examinations conducted by the research group, in vivo EPR spectroscopy and imaging (EPRI) with a nitroxide spin probe were used. Buthionine sulfoximine (BSO), as a GSH synthesis inhibitor, was applied to decrease the level of GSH in a tissue. The subject was tumour-bearing mice with implanted radiation-induced fibrosarcoma (RIF-1) tumour growing in the right leg. The normal tissue from the left leg was used as a control.
The results of experiments have confirmed the hypothesis posed by the research group. It has been shown that physiological parameters such as redox status, in the normal tissue and in the neoplastic tissue significantly differ from each other. Obtained data showed that it was a higher concentration of GSH in malignant tissue. It was also noted that BSO treatment causes differences in reduction of GSH level. Tumour tissue showed higher reduction rate in comparison to healthy tissue. Physiological differences between malignant tissue and normal tissue are a significant factor involved in improving cancer treatments, and what is important, EPR technique is a very promising and helpful tool in such researches.
Kuppusamy P. et al.; Noninvasive imaging of tumor redox status and its modification by tissue glutathione levels; Cancer Res. 2002 Jan 1;62(1):307-12.