A comparative study of some growth characteristics and cell-surface properties of neoplastic cells

Abstract

Summary.-Tumour cells from a polyoma-induced ascitic tumour were fractionated on the basis of the electrical charge on the cell surface by free-flow electrophoresis. Several characteristics of tumour cells have been investigated: (1) differences in the proliferation and antigenicity within the tumour at any point in time; (2) variation in proliferative potential with the ageing of the tumour.In early ascitic tumours, electrophoretically fractionated cells exhibit very similar proliferative characteristics. However, most DNA synthesis was found in slowmoving cells. The behaviour of older tumours was different. Proliferative potential and DNA synthesis were weaker and restricted to slow-moving cells, suggesting that fast-moving cells in older tumours were resting cells. An enrichment in immunoglobulin-bearing cells was also found in slow-moving cell fractions, supporting the hypothesis of variability in expression of tumour-specific antigens. The role of cellsurface properties and cell kinetics is discussed in relation to electrical surface charge, which might be involved in cell dissemination and metastasis. Thus, freeflow electrophoresis represents a satisfactory approach to isolate tumour cell subpopulations with characteristics such as high proliferative potential or increased expression of tumour antigens.

Targeted photodestruction of human colon cancer cells using charged 17.1A chlorine6 immunoconjugates

“…In this previous study the charge effect was found to be of larger magnitude but in the same direction as the present study, with the polycationic PIC having 6 times the uptake and 10 times the phototoxicity of the polyanionic PIC. This difference in magnitude between charge effects may be attributed to differences in the magnitude of the negative charge expressed on the outside of the cells (Bischoff et al, 1981), or to differences in the extent to which polycations stimulate endocytosis between cell lines (Duncan et al, 1979). It is accepted that imparting cationic charge to a protein 24.5 ± 1.31…”