Fever-Range Hyperthermia vs. Hypothermia Effect on Cancer Cell Viability, Proliferation and HSP90 Expression

Abstract

PurposeThe current study examines the effect of fever-range hyperthermia and mild hypothermia on human cancer cells focusing on cell viability, proliferation and HSP90 expression.Materials and MethodsA549 and H1299 lung carcinoma, MCF7 breast adenocarcinoma, U87MG and T98G glioblastoma, DU145 and PC3 prostate carcinoma and MRC5 normal fetal lung fibroblasts cell lines were studied. After 3-day exposure to 34°C, 37°C and 40°C, cell viability was determined. Cell proliferation (ki67 index), apoptosis (Caspase 9) and HSP90 expression was studied by confocal microscopy.ResultsViability/proliferation experiments demonstrated that MRC5 fibroblasts were extremely sensitive to hyperthermia, while they were the most resistant to hypothermia. T98G and A549 were thermo-tolerant, the remaining being thermo-sensitive to a varying degree. Nonetheless, as a universal effect, hypothermia reduced viability/proliferation in all cell lines. Hyperthermia sharply induced Caspase 9 in the U87MG most thermo-sensitive cell line. In T98G and A549 thermo-tolerant cell lines, the levels of Caspase 9 declined. Moreover, hyperthermia strongly induced the HSP90 levels in T98G, whilst a sharp decrease was recorded in the thermo-sensitive PC3 and U87MG cell lines. Hyperthermia sensitized thermo-sensitive cancer cell lines to cisplatin and temozolomide, whilst its sensitizing effect was diminished in thermo-tolerant cell lines.ConclusionsThe existence of thermo-tolerant and thermo-sensitive cancer cell lines was confirmed, which further encourages research to classify human tumor thermic predilection for patient stratification in clinical trials. Of interest, mild hypothermia had a universal suppressing effect on cancer cell proliferation, further supporting the radio-sensitization hypothesis through reduction of oxygen and metabolic demands.

Therapeutic interactions of autophagy with radiation and temozolomide in glioblastoma: evidence and issues to resolve

“…Autophagic flux studies in cancer cells are demanded to elucidate the phenomenon, and such studies are absent in the literature. Our studies in normal fibroblasts and endothelial cells suggest that radiation results in an early blockage of the autophagic flux within the first days of irradiation ( Kalamida et al , 2015 ). The increase of LC3-II membrane-bound form in the soluble fraction of cells instead of the pellet fraction and the sharp increase of p62 protein (that normally disintegrates in the autophagolysosomal environment once incorporated) strongly suggest that radiation induces a non-functional accumulation of autophagosomes in cells, inducing autophagic death in a similar way that late phase autophagy blockers (such as chloroquine and bafilomycin) do.…”

Comparative effects of magnetic and water-based hyperthermia treatments on human osteosarcoma cells

“…Glioblastoma U87MG and T98G expressed increased levels of Caspase 9 and heat shock protein 90 as markers of induced apoptosis compared to more thermo-tolerant A549 and H1299 lung carcinoma, U87MG breast adenocarcinoma, and PC8 prostate cancer cell lines after 3 days exposure to temperatures ranging from 33°C to 40°C. 24 In this study, we compared the heat sensitivity of hOS cells incubated in a laboratory-made incubator with or without MNPs and subjected to WHT at different treatment temperatures (39°C-49°C) for 1 hour. Cell viability was evaluated immediately after treatment using the MTT assay.…”

Magnetic hyperthermia therapy for the treatment of glioblastoma: a review of the therapy’s history, efficacy and application in humans

“…An increase in the local temperature to values between 40 and 44 °C is sufficient to negatively impact cancer growth [22,23]. The interactions of heat with RT and chemotherapy and the effects of heat on cancer cells have already been described [24,25].…”

“…There are several proposed mechanisms of HT-induced chemosensitisation, including generation of a transient disruption of the blood–brain barrier (BBB), increased blood flow that accompanies hyperthermia conditions, interference with DNA repair mechanisms, heat-induced damage to ATP-binding cassette (ABC) transporters, changes in tumour cell drug metabolism, and an impaired ability to withstand apoptotic pathways [23,25,34–38]. …”