Hyperthermia induced NFkappaB mediated apoptosis in normal human monocytes

Area of Science:

• Oncology
• Cell Biology
• Molecular Biology

Background:

• Hyperthermia treatment (HT) is explored for cancer therapy, but its effects on normal tissues require careful evaluation to optimize the therapeutic index.
• Understanding the molecular mechanisms of HT-induced cytotoxicity in normal cells is crucial for safe and effective clinical application.

Purpose of the Study:

• To investigate the impact of HT on apoptosis, cell cycle, and NF-kappaB signaling in normal human Mono Mac 6 (MM6) cells.
• To elucidate the role of IkappaBalpha phosphorylation and NF-kappaB mRNA expression in HT-induced cellular responses.

Main Methods:

• Cells were exposed to 43°C for hyperthermia treatment (HT).
• Flow cytometry (FACS) analyzed apoptosis and cell-cycle distribution.
• Electrophoretic mobility shift assay (EMSA) assessed NF-kappaB DNA-binding activity.
• Immunoblotting detected IkappaBalpha phosphorylation.
• Ribonuclease protection assay (RPA) quantified NF-kappaB mRNA levels.

Main Results:

• HT induced a significant increase in apoptosis (48.5%) and altered cell-cycle distribution (increased S-phase, reduced G2-phase).
• HT caused dose-dependent inhibition of NF-kappaB DNA-binding activity, which persisted for at least 48 hours.
• HT also inhibited IkappaBalpha phosphorylation and NF-kappaB mRNA expression in a dose-dependent and persistent manner.

Conclusions:

• Apoptosis induction in MM6 cells by HT is mediated by the suppression of NF-kappaB signaling.
• The observed inhibition of NF-kappaB is linked to decreased IkappaBalpha phosphorylation and persistent reduction in NF-kappaB mRNA levels.
• These findings highlight the molecular pathways affected by HT in normal cells, informing strategies to enhance therapeutic efficacy and minimize toxicity.