Kalamida Dimitra, Karagounis Ilias V, Mitrakas Achilleas, Kalamida Sofia, Giatromanolaki Alexandra, Koukourakis Michael I
Department of Radiotherapy/Oncology, Democritus University of Thrace, Alexandroupolis, 68100, Greece.
Department of Pathology, Democritus University of Thrace, Alexandroupolis, 68100, Greece.
PLoS One. 2015 Jan 30;10(1):e0116021. doi: 10.1371/journal.pone.0116021. eCollection 2015.
The current study examines the effect of fever-range hyperthermia and mild hypothermia on human cancer cells focusing on cell viability, proliferation and HSP90 expression.
A549 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.
Viability/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.
The 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.
本研究聚焦于细胞活力、增殖和热休克蛋白90（HSP90）表达，考察发热范围的高温和轻度低温对人癌细胞的影响。
研究了A549和H1299肺癌细胞系、MCF7乳腺腺癌细胞系、U87MG和T98G胶质母细胞瘤细胞系、DU145和PC3前列腺癌细胞系以及MRC5正常胎儿肺成纤维细胞系。在分别暴露于34°C、37°C和40°C 3天后，测定细胞活力。通过共聚焦显微镜研究细胞增殖（Ki67指数）、凋亡（半胱天冬酶9）和HSP90表达。
活力/增殖实验表明，MRC5成纤维细胞对高温极为敏感，而对低温最具抗性。T98G和A549具有热耐受性，其余细胞系在不同程度上对热敏感。尽管如此，作为一种普遍效应，低温降低了所有细胞系的活力/增殖。高温在对热最敏感的U87MG细胞系中急剧诱导半胱天冬酶9。在具有热耐受性的T98G和A549细胞系中，半胱天冬酶9水平下降。此外，高温强烈诱导T98G中的HSP90水平，而在对热敏感的PC3和U87MG细胞系中则记录到急剧下降。高温使对热敏感的癌细胞系对顺铂和替莫唑胺敏感，而其敏化作用在具有热耐受性的细胞系中减弱。
证实了存在具有热耐受性和对热敏感的癌细胞系，这进一步鼓励开展研究，以便在临床试验中对人类肿瘤的热偏好进行分类，用于患者分层。有趣的是，轻度低温对癌细胞增殖具有普遍的抑制作用，通过降低氧气和代谢需求进一步支持了放射增敏假说。
