Inhibition of growth, degeneration of microvilli, cytoplasmic lipidosis, and other alterations of HeLa cells incubated with oleate

HeLa cells cultured in suspension in S. MEM (Gibco's F 13) double in number during the first 24 hr at 37 C and continue to grow at approximately the same rate during a second 24 hr incubation period. But when sodium (or lithium) oleate, 40 to 70 μg/ml, is added the cells fail to grow or grow only poorly, the degree of inhibition varying from 0 to 100%, depending upon the concentration of oelate employed and the duration of the contact. During 2 hours' incubation with oleate (45 to 55 μg/ml), the HeLa cells regularly manifested abnormal blebbing of their plasma membranes (ordinary light and interference microscopy), marked degeneration of their microvilli (scanning electron microscopy), and conspicuous cytoplasmic lipidosis (ordinary high microscopy and transmission electron microscopy). These marked cellular changes usually proved reversible when the lesser concentrations of oleate were used, but they always progressed to necrosis within 1 or 2 hr when the larger concentrations of oleate had been added. Sodium acetate (100 to 3200 μg/ml) regularly brought about a transitory inhibition of growth without any consequential necrosis during incubation periods lasting up to 96 hr. The carbonic anhydrase inhibitor, Diamox (100 μg/ml and more) also gave rise to transitory inhibition of growth, again without consequential necrosis. A possible explanation of the findings is that sodium oleate's detergency might alter the microvilli of metabolizing HeLa cells, thus interfering with assimilation of essential bicarbonate and/or disposal of carbonic acid.