Double Labeling and Simultaneous Monitoring for Hsp70 and Hsf-1 Kinetics in SCC-25 Cells with a Short-Term Dietary Restriction of Leucine Following Heat Shock

Abstract

To develop a quantum-dot-based multiplexed imaging system for the simultaneous monitoring of Hsf-1/Hsp70 after heat shock, and to evaluate the effects of combined thermotherapy and leucine deprivation therapy on Hsf-1 inactivation. SCC-25 cells were leucine starved for 0, 1, 2, 3 or 4 days following which the cells underwent heat shock at 42°C for 30 min. At 6 h after heat shock, Hsf-1 activation and translocation to the nucleus was observed in cells that were leucine starved for 0, 1 and 2 days, and the synthesis of Hsp70 and Hsf-1 reached their maximum values and had a tendency to gather in the nucleus. However, in cells that were leucine starved for 3 and 4 days, Hsf-1 activity and Hsp70 synthesis level was dramatically decreased. Dietary restriction of leucine for at least three days could result in the inactivation of Hsf-1, leading to a reduction in Hsp70 synthesis. The combination of thermotherapy and short-term leucine deprivation therapy may become effective approach for the treatment of oral tumors.