Hypothermia causes a reversible, p53-mediated cell cycle arrest in cultured fibroblasts

Normal human fibroblasts grown in cell culture undergo a reversible growth arrest when incubated at 28 degrees C. During incubation at 28 degrees C, l evels of p53 and p21 rise in these cells and cell cycle analysis shows that they have undergone a cell cycle arrest. To examine the importance of p53 in mediating this arrest, mouse embryo fibroblasts that are either wildtype or that are defective in p53 were also subjected to hypothermia. Only thos e cells with wild-type p53 undergo a cell cycle arrest, indicating that p53 has a role in mediating this response. Because many tumor cells have detec tive p53, this suggests that hypothermia may increase the selective toxicit y of chemotherapeutic agents for tumor cells.