Enzyme activities and level of SH groups in breast carcinomas

Glutathione levels in human tumors

This review summarizes clinical studies in which glutathione was measured in tumor tissue from patients with brain, breast, gastrointestinal, gynecological, head and neck and lung cancer. Glutathione tends to be elevated in breast, ovarian, head and neck, and lung cancer and lower in brain and liver tumors compared to disease-free tissue. Cervical, colorectal, gastric, and esophageal cancers show both higher and lower levels of tumor glutathione. Some studies show an inverse relationship between patient survival and tumor glutathione. Based on this survey, we recommend approaches that may improve the clinical value of glutathione as a biomarker.

Effects of glutamine on head and neck squamous cell carcinoma

Glutamine supplements are being studied as protectants against the mucositis associated with radiation therapy of head and neck squamous cell carcinoma. Glutamine is an important amino acid for the maintenance of healthy gut function and nitrogen transport. It is also a preferred energy source for many types of tumors through an altered Krebs cycle. The effects of glutamine supplements on the growth of head and neck squamous cell carcinoma have not been studied. Eighteen nude mice were implanted with one established cell line, and 18 were implanted with another. The mice were paired and fed either a glutamine-rich or a glutamine-poor diet. There was not a statistically significant difference in the growth rates of the xenografts or in the weight gain of the mice between the diet groups. These findings are encouraging for the continued use of glutamine supplements in patients with head and neck squamous cell carcinoma.

Antioxidant and glutathione-associated enzymes in Wilms' tumour after chemotherapy

The present study demonstrates the activities of antioxidant and glutathione-associated enzymes and the level of glutathione in Wilms' tumour (nephroblastoma) samples after chemotherapy (mainly actinomycin D and vincristine). We observed higher activity of superoxide dismutase in Wilms' tumour compared to adjacent morphologically unchanged kidney. On the other hand, in this tumour lower activities of catalase and the glutathione-associated enzymes glutathione synthetase, gamma-glutamyl transpeptidase, glutathione reductase and total glutathione S-transferases (GST) were found. Using isoelectric focusing we separated different forms of GST in tested tissues and revealed lower activities of the basic enzymes in Wilms' tumour, which may be responsible for the decrease of total GST activity. Moreover, we found the acidic isoenzymes to be the predominant class of GST in nephroblastoma. In Wilms' tumours with unfavourable histology a high activity of these isoenzymes together with a high level of GSH were observed. We suggest that these parameters may participate in the known phenomenon of anticancer drug resistance of tumours with unfavourable histology.