Synergistic inhibition of autophagic flux and induction of apoptosis in cervical cancer cells by Mito-TEMPO and hyperthermia.
- Author:
Yu-Mei LI
1
;
Qing-Li ZHAO
1
;
Ryohei OGAWA
1
;
Tatsuji MIZUKAMI
1
;
Yu SONG
1
;
Zheng-Guo CUI
2
;
Jun-Ichi SAITOH
1
;
Kyo NOGUCHI
1
Author Information
- Publication Type:Journal Article
- Keywords: Apoptosis; Autophagy; Endoplasmic reticulum stress; Hyperthermia; Mito-TEMPO
- MeSH: Humans; Apoptosis/drug effects*; Autophagy/drug effects*; HeLa Cells; Uterine Cervical Neoplasms/therapy*; Female; Hyperthermia, Induced; Spin Labels; Endoplasmic Reticulum Stress/drug effects*; Cyclic N-Oxides/pharmacology*; Cell Survival/drug effects*
- From:Environmental Health and Preventive Medicine 2025;30():67-67
- CountryJapan
- Language:English
-
Abstract:
BACKGROUND:Hyperthermia (HT), while a cancer treatment approach, isn't always effective alone. Therefore, identifying hyperthermia enhancers is crucial. We demonstrated that Mito-TEMPO ([2-[(1-Hydroxy-2,2,6,6-tetramethylpiperidin-4-yl) amino]-2-oxoethyl]-triphenylphosphanium, MT) acts as a potent thermosensitizer, promoting cell death in human cervical cancer (HeLa) cells.
METHODS:Cells were pretreated with 0.4 mM MT for 5 minutes, followed by exposure to hyperthermia (42 °C for 60 minutes). The impacts of MT/HT on cell viability, proliferation, apoptosis, endoplasmic reticulum (ER) stress, apoptosis-related proteins and autophagy, autophagy-related proteins expression were measured. The relationships between autophagy and apoptosis were further investigated using the specific autophagy inhibitor chloroquine (CQ) and the autophagy inducer rapamycin (Rapa).
RESULTS:The combined treatment reduced the mitochondrial membrane potential (MMP) and increased ROS production. It also upregulated the pro-apoptotic protein Bax and downregulated anti-apoptotic proteins such as Bcl-2 and MCL-1. As a result, Caspase-3 was activated. Additionally, the combined treatment upregulated the expression of p-PERK/PERK, ATF-4, CHOP proteins. Moreover, the combined treatment also increased the expression of LC3 II and p62, decreased expression of LAMP 1 and Cathepsin D and increased lysosomal pH, indicating coordinated changes in autophagy regulation. Notably, intensification of apoptosis induced by the combined treatment was observed with CQ, whereas attenuation was seen with Rapa.
CONCLUSIONS:MT effectively enhanced HT-induced apoptosis in HeLa cells. Elevated ER stress and interruption of autophagy flux are the possible underlying molecular mechanisms for this phenomenon. These findings suggested MT can act as a potential thermosensitizer, highlighting its versatility in cancer treatment strategies.
