72-kD heat shock protein is a mediator of resistance to ultraviolet B light

J Invest Dermatol. 1995 Aug;105(2):160-2. doi: 10.1111/1523-1747.ep12317003.


We have shown previously that human epidermal keratinocytes in situ and in vitro constitutively express high levels of the 72-kD heat shock protein (hsp72) and that hsp72 expression in these cells can be further induced with heat treatment. In the present study, we continue our investigation of the ultraviolet (UV) B protective effect of hyperthermic treatment and ask whether hsp72 is a mediator of heat-shock-induced UVB resistance. The results of our experiments demonstrate that heat treatment (42 degrees C for 4 h) before UVB exposure is able to increase significantly the UVB resistance of the epidermal carcinoma cell line A431. Heat-induced UVB resistance was most pronounced if the cells were exposed to UVB immediately after heat treatment. The protective effect was not detectable beyond a recovery period of 12 h. To investigate the role of hsp72 in hyperthermia-induced UVB resistance, we inhibited the expression of this protein using either a specific antisense oligodeoxynucleotide or quercetin, a flavonoid that has been shown to down-regulate hsp expression. Treatment with the oligomer as well as with quercetin significantly increased the susceptibility of A431 to UVB-induced damage and nullified the protective effect of heat preconditioning. A noncomplementary control oligodeoxynucleotide had no significant effect. These results indicate that heat treatment is able to induce a state of increased resistance to the deleterious effects of UVB in human keratinocytes in vitro. hsp72 is a molecular mediator of this protective effect, and its constitutive expression in human epidermal keratinocytes may be an important mechanism for the protection of human epidermis from UVB-induced damage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cell Survival
  • Epidermis / pathology
  • Epidermis / physiopathology*
  • Epidermis / radiation effects*
  • HSP72 Heat-Shock Proteins
  • Heat-Shock Proteins / antagonists & inhibitors
  • Heat-Shock Proteins / physiology*
  • Hot Temperature
  • Humans
  • Molecular Sequence Data
  • Oligonucleotide Probes / genetics
  • Oligonucleotides, Antisense / pharmacology
  • Quercetin / pharmacology
  • Tumor Cells, Cultured
  • Ultraviolet Rays*


  • HSP72 Heat-Shock Proteins
  • Heat-Shock Proteins
  • Oligonucleotide Probes
  • Oligonucleotides, Antisense
  • Quercetin