Cell Death Induced in a Murine Mastocytoma by 42–47°C Heatingin Vitro: Evidence that the Form of Death Changes from Apoptosis to Necrosis Above a Critical Heat Load

Abstract

The pathogenesis of heat-induced cell death is controversial. Categorizing the death occurring after various heat loads as either apoptosis or necrosis might help to elucidate this problem, since it has been shown that these two processes differ in their mode of initiation as well as in their morphological and biochemical features. Log-phase cultures of mastocytoma P-815 x 2.1 were heated at temperatures ranging from 42 to 47 degrees C for 30 min. After 42 degrees C heating a slight increase in apoptosis was observed morphologically. However, after heating at 43, 43.5 and 44 degrees C, there was marked enhancement of apoptosis, and electrophoresis of DNA showed characteristic internucleosomal cleavage. With heating at 45 degrees C both apoptosis and necrosis were enhanced, whereas at 46 and 47 degrees C only necrosis was produced. DNA extracted from the 46 and 47 degrees C cultures showed virtually no degradation, which contrasts with the random DNA breakdown observed in necrosis produced by other types of injury; lysosomal enzymes released during heat-induced necrosis may be inactivated at the higher temperatures. It is suggested that apoptosis following heating may be triggered either by a limited increase in cytosolic calcium levels resulting from mild membrane changes or by DNA damage. Necrosis, on the other hand, is likely to be a consequence of severe membrane disruption.

Multiplication and death-type of leukemia cell lines exposed to very long-chain polyunsaturated fatty acids

“…A temperature of 42-44°C will induce apoptosis in mastocytoma cells, whereas necrosis results if they are exposed to 46-47°C. 30 However, we could not observe any changes in the type of cell death in Raji with lower concentrations of EPA (30 or 45 mol/l, data not shown). Thus, the response to EPA is probably dependent on cell type.…”

“…The microscopic smears revealed that the cell membrane remained intact during most of the incubation period (until 36 h), and that the cells had fragmented nuclei and intense HO342 fluorescence, indicative of condensed chromatin (Figure 3c). At 48 h, 87% of the cells were PI-positive, indicating membrane leakage, which commonly occurs in cells undergoing apoptosis in vitro when no phagocytes are present ('secondary necrosis'), 30 and 45% of the cells had fragmented DNA. The discrepancy between these two percentages, is most likely due to a loss of necrotic cells during preparation for TUNEL analyses, which includes fixation, permeabilization and several washes of the cells.…”

Heat stress induces different forms of cell death in sea anemones and their endosymbiotic algae depending on temperature and duration

“…There is very little or no evidence of membrane rupture during PCD. Scale bars ¼ 2 mm initiated as a stress response, but the cells are unable to sustain PCD during prolonged heat stress due to progressive protein degradation, 28 membrane disruption 29 and/or ATP depletion. 30,31 Damaged cells subsequently undergo necrosis rather than PCD.…”

“…Alternatively, PCD activity may have been reduced by the stress-mediated upregulation of heat shock proteins that are known inhibitors of PCD. [6][7][8] A shift from PCD to necrosis occurs in several vertebrate systems in response to temperature, 29,32 other stressors and disease. [33][34][35] A similar pattern in the anemone, a lower invertebrate, suggests that the mechanisms controlling the shift between different forms of cell death in response to stress may be highly conserved.…”

Changes in nuclear phenotypes following cold shock in Panstrongylus megistus (Burmeister)

“…If the stress damage is very severe, necrosis predominates (Lindquist & Craig 1988, Harmon et al 1990, Sakaguchi et al 1995, Samali & Cotter 1996. Although the effects of a short cold shock in P. megistus are not completely controlled by hsp or survival mechanisms involving cell/nuclear fusions and heterochromatin unravelling since cell death mechanisms are elicited, cell death was not grave enough to affect the survival of more than 14% of the 5th instar nymphs of P. megistus after this shock (Garcia et al 1999b).…”