Differential temperature sensitivity of normal and cancer cells in culture

Serially‐propagated growing heteroploid and growing diploid cell cultures do not survive incubation at 42° for 24 hours, whereas contact‐inhibited diploid monolayers are still viable after at least nine days at this elevated temperature. Heat‐treated heteroploid HeLa cells and growing diploid cells exhibit a variety of morphologic abnormalities, but contact‐inhibited cells are only minimally affected. A similar differential temperature sensitivity exists in the synthesis of cellular macromolecular components such as DNA, RNA, and protein: incorporation of radioactive precursors is drastically reduced in growing diploid and heteroploid cells after 24 hours at 42°, but not in contact‐inhibited cells. Incorporation of labelled glucose, choline, or linolenic acid is actually enhanced in heat‐treated contact‐inhibited cells.