Effect of ploidy, recruitment, environmental factors, and tamoxifen treatment on the expression of sigma-2 receptors in proliferating and quiescent tumour cells.

Abstract

Recently, we demonstrated that sigma-2 receptors may have the potential to be a biomarker of tumour cell proliferation (Mach et al (1997) Cancer Res 57: 156-161). If sigma-2 receptors were a biomarker of tumour cell proliferation, they would be amenable to detection by non-invasive imaging procedures, thus eliminating many of the problems associated with the flow cytometric measures of tumour cell proliferation presently used in the clinic. To be a good biomarker of tumour cell proliferation, the expression of sigma-2 receptors must be essentially independent of many of the biological, physiological, and/or environmental properties that are found in solid tumours. In the investigation reported here, the mouse mammary adenocarcinoma lines, 66 (diploid) and 67 (aneuploid), 9L rat brain tumour cells, and MCF-7 human breast tumour cells were used to study the extent and kinetics of expression of sigma-2 receptors in proliferative (P) and quiescent (Q) tumour cells as a function of species, cell type, ploidy, pH, nutrient depletion, metabolic state, recruitment from the Q-cell compartment to the P-cell compartment, and treatment with tamoxifen. In these experiments, the expression of sigma-2 receptors solely reflected the proliferative status of the tumour cells. None of the biological, physiological, or environmental properties that were investigated had a measurable effect on the expression of sigma-2 receptors in these model systems. Consequently, these data suggest that the proliferative status of tumours and normal tissues can be non-invasively assessed using radiolabelled ligands that selectively bind sigma-2 receptors.

• Authors: I Al-Nabulsi, R H Mach, L M Wang, C A Wallen, P C Keng, K Sten, S R Childers, K T Wheeler
• Journal: British journal of cancer (Br J Cancer) Vol. 81 Issue 6 Pg. 925-33 (Nov 1999) ISSN: 0007-0920 [Print] England
• PMID: 10576647 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Antineoplastic Agents, Hormonal
• Biomarkers, Tumor
• Receptors, sigma
• Tamoxifen

Topics

• Adenocarcinoma (drug therapy, metabolism, pathology)
• Animals
• Antineoplastic Agents, Hormonal (pharmacology)
• Biomarkers, Tumor (analysis)
• Brain Neoplasms (drug therapy, metabolism, pathology)
• Breast Neoplasms (drug therapy, metabolism, pathology)
• Cell Division
• Female
• Humans
• Mammary Neoplasms, Experimental (drug therapy, metabolism, pathology)
• Mice
• Ploidies
• Rats
• Receptors, sigma (analysis, biosynthesis)
• Tamoxifen (pharmacology)
• Tumor Cells, Cultured