Overcoming the radioresistance of prostate cancer cells with a novel Bcl-2 inhibitor.

Bcl-2 overexpression is an important mechanism underlying the aggressive behavior of prostate cancer cells and their resistance to radio- or chemotherapy. HA14-1, a recently discovered organic Bcl-2 inhibitor, potently induces apoptosis in various human cancer cells. Sequential exposure of radioresistant LNCaP (wild-type (wt) p53), LNCaP/Bcl-2 (wt p53) and PC3 (mutant p53) prostate cancer cells to a minimally cytotoxic concentration of 10 microM HA14-1 for 1 h followed by 1-6 Gy gamma radiation, resulted in a highly synergistic (combination index <1.

Thermotolerance in chicken red blood cells studied by 31P NMR spectroscopy.

Chicken red bloods cells (RBCs) were used as a model for cell survival following hyperthermia of differentiated cells, with rat RBCs serving as controls. The purpose was to investigate whether cells heated at 51.5 degrees C with or without prior heat shock exhibited discernible differences in phosphorus metabolites, intracellular pH or Mg2+ using 31P nuclear magnetic resonance spectroscopy.

The effects of ionizing radiation on avian erythrocytes.

The effects of ionizing radiation were examined in terminally differentiated cells using nucleated chicken erythrocytes (RBCs) as the model. We used a hemolytic assay to score radiation damage to RBCs. Chicken RBCs received 0 to 100 Gy of radiation at dose rate of 10 Gy/min.

Effects of hyperthermia on avian red blood cells.

Our primary goal was to develop a model for studying the effects of heat on terminally differentiated cells. Using nucleated chicken red blood cells (RBC) as the model, heat dose-response and thermotolerance were investigated. A new haemolytic assay was developed to score them.

Radiation factors and their influence on induction of oxygen resistance.

Shortly after gamma irradiation, flour beetles exhibited a decline in resistance to oxygen toxicity. Then, about 2 weeks after irradiation, the 50% lethal dose (LD50) exposure time in pure oxygen was much greater than that of nonirradiated beetles, and this enhanced resistance persisted for about 6 months. The magnitude of the enhancement was a function of dose, decreased with increasing age at irradiation, and was modified by radiation factors.

Radiation-enhanced resistance to oxygen: a possible relationship to radiation-enhanced longevity.

Shortly after gamma-irradiation, flour beetles (Oklahoma strain of Tribolium confusum) exhibited a decline in resistance to oxygen toxicity. Beginning about two weeks after irradiation, however, the LD50 exposure time in pure oxygen was much greater than that of nonirradiated beetles, and this enhanced resistance persisted for about 6 months. The magnitude of the enhancement was a function of dose, and decreased with increasing age at irradiation.

Repair studies utilizing a fly-pupariation model of postmitotic cell response.

Delay in pupariation of irradiated fly (and other insect) larvae results from a neuroendocrine disturbance and represents a dose-dependent response of differentiated postmitotic tissue. Many experimental manipulations (e.g.

Age and sensitivity to oxygen in the flour beetle, Tribolium confusum.

Sensitivity of Tribolium confusum males and females to pure oxygen at one atmosphere was measured as a function of adult age. Sensitivity to oxygen increased markedly with age; the reciprocal to the LD50 exposure time was a linear function of age. The sensitivity to oxygen increased more rapidly with age in males than in females; this may be related to the greater longevity of females in this species.