Mitochondrial damage in nasopharyngeal carcinoma cells induced by ultrasound radiation in the presence of hypocrellin B.
OBJECTIVE
The mitochondrion is an important target of ultrasound-induced cell death. This study aimed to investigate the mitochondrial damage in nasopharyngeal carcinoma (NPC) cells induced by ultrasound radiation in the presence of hypocrellin B (HB).


METHODS
The NPC cell line CNE2 was used to investigate the effect of HB on ultrasonic action with an HB concentration of 2.5 mumol/L and ultrasound exposure for 15 seconds at an intensity of 0.65 W/cm(2). Cytotoxicity was investigated 24 hours after ultrasound exposure. Mitochondrial structure changes were observed by transmission electron microscopy. The mitochondrial membrane potential was evaluated by confocal laser-scanning microscopy with rhodamine 123 staining.


RESULTS
The mean death rates of the CNE2 cells +/- SD were 25.14% +/- 1.50% after ultrasound radiation alone and 76.72% +/- 1.13% after ultrasound radiation in the presence of HB. Transmission electron microscopy showed that slightly enlarging mitochondria were found in the ultrasound-treated cells. After treatment with ultrasound and HB together, some cells had seriously damaged mitochondria, namely, obvious swollen mitochondria and mitochondria in which cristae had almost completely disappeared. The mitochondrial membrane potential was more significantly collapsed when the CNE2 cells were exposed to HB for 5 hours and then ultrasound at 0.65 mW/cm(2) than with ultrasound radiation alone (P < .05).


CONCLUSIONS
Hypocrellin B significantly enhanced the cytotoxicity of ultrasound radiation in the CNE2 cells. The damage to the mitochondrial structure and function might be an important cause of death in the CNE2 cells induced by treatment with ultrasound radiation and HB together.
Wang
Ping
P
Department of Photodynamic and Sonodynamic Therapy, Second Affiliated Hospital, Chongqing Medical University, Yu Zhong District, Chongqing 400010, China.
Xu
Chuanshan
C
Xia
Xinshu
X
Xu
Jing
J
Wang
Xinna
X
Xiang
Junyan
J
Leung
Albert Wingnang
AW
D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D045744:Cell Line, Tumor; D006801:Humans; D008928:Mitochondria / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects*; D009303:Nasopharyngeal Neoplasms / Q000473:pathology* / Q000628:therapy*; D010569:Perylene / Q000008:administration & dosage / Q000031:analogs & derivatives*; D011809:Quinones / Q000008:administration & dosage*; D011829:Radiation Dosage; D011838:Radiation-Sensitizing Agents / Q000627:therapeutic use; D016896:Treatment Outcome; D014464:Ultrasonic Therapy / Q000379:methods*
D011809:Quinones; D011838:Radiation-Sensitizing Agents; D010569:Perylene; C064522:hypocrellin B