The primary area of investigation of the Rich Laboratory is the role of apoptosis after treatment of glioma cells with DNA-damaging agents. We are examining p53 and bcl-2 family gene expression in human glioma with lines. More recently, we have expanded studies to models of death in glioma cells. Methods include a variety of immuno-fluorescent cell-staining techniques, cell culture and molecular techniques such as PCR and development of clones.
Primary malignant brain tumors respond poorly to treatment with chemo- and radiotherapy. The great majority of these tumors are resistant to long-term control, and patients survive usually only a couple of years after diagnosis. Alterations in expression of p53 and bcl-2 gene family members influence cell growth and apoptotic death in a number of types of tumors, but their roles, either individually or together, in determining the biological behavior of gliomas, have not been well defined. Our laboratory has directed studies aimed at evaluating the importance of p53 and bcl-2 gene family member function on cellular proliferation and death in gliomas after treatment with the DNA-damaging agents commonly used clinically, as well as with newer treatment strategies undergoing laboratory and/or clinical investigation. With use of human glioma cell lines, e.g., U87 (which expresses wild-type p53) and U373 (which expresses only mutant p53), we are evaluating the hypothesis that regulation of the ratio of promotors of apoptosis to inhibitors will determine radio- and chemosensitivity in gliomas. Clones will be constructed that over-express wild-type P53 and Bax. The effects of these transfections on chemo- and radiosensitivity will be correlated with the changes in the ratio of promotors to inhibitors of apoptosis.
This hypothesis will be tested in specimens directly obtained from patients. Fresh tissue is snap-frozen in liquid nitrogen and stored in the Washington University Tumor Repository. Specimens will be available for studies with RNA, DNA and protein from these tumors. In selected situations, the specimens from the operating room will be used to generate clonal tumor lines in our laboratory for use in studies outlined above. The work is supported by a grant from the National Institute of Health and has been approved by the Washington University Human Studies Committee.