Neoplastic transformation produces many changes in cell physiology, some of which can be studied using morphologic techniques. We have used morphologic methods to study three general areas: 1) We have used light microscopic cytochemical methods to isolate and characterize monoclonal antibodies to antigens present on ovarian cancer cells for use in diagnosis and in the construction of immunotoxins for therapy of human cancer. We had previously isolated OVB3, an antibody currently being evaluated in phase I clinical trials as an immunotoxin; the isolation of similar tumor- specific antibodies is an on-going project. Technical improvements have streamlined the morphologic hybridoma screening processing time to less than two days, allowing primary screening on cultured cells and secondary screening on tissue samples with the same initial 100 mu L supernatant sample. 2) We have studied aspects of multidrug-resistance of human tumors in cultured cells and in tissues. We have localized P170, the product of the human MDR1 gene, in normal tissues using monoclonal antibody MRK16, and in addition to its location in the GI tract, adrenal, kidney and liver, we have also found it in capillaries in the central nervous system. We have studied the reactivity of monoclonal antibody C219 that reacts with an epitope of P170 present on the inner surface of the plasma membrane, and found that this antibody cross-reacts with other proteins in some tissues, such as the heavy chain of cardiac and slow-twitch muscle myosin, in human, monkey, and rat tissues. We have also examined the expression of human P170 introduced through a viral vector in MDCK cells and found that P170 is expressed in a polarized fashion on the apical surface of these cells, similar to its distribution in normal kidney proximal tubules. 3) In other studies, we have examined the effects of microinjected protein kinase C on cell morphology; we have localized the E5 oncogene product from papilloma virus in cultured cells; we have also localized monoclonal antibodies of nuclear pore carbohydrate epitopes using immunocytochemistry and microinjected lectins; and we have localized P58, a major thyroid hormone binding protein, to the cytosol of rapidly growing cells.
