Hematoporphyrin monomethyl ether enhances the killing of ultrasound on osteosarcoma cells involving intracellular reactive oxygen species and calcium ion elevation.
OBJECTIVE
The present study aims to investigate the possible mechanisms of hematoporphyrin monomethyl ether (HMME) enhancing the cytotoxicity of ultrasound in osteosarcoma cells.


METHODS
Osteosarcoma cell line UMR-106 was treated by HMME and ultrasound radiation, with the HMME concentration kept at 20 μg/mL and ultrasound radiation for 10 seconds at the intensity of 0.5 W/cm². Cell proliferation was investigated at 12, 24, 36, and 48 hours using MTT assay after ultrasound and HMME treatment. Ultrastructural morphology was observed using transmission electron microscopy (TEM). Intracellular reactive oxygen species (ROS) was measured using a flow cytometry with DCFH-DA staining and intracellular free calcium ion (Ca(2+)) with Fluo-3-AM staining.


RESULTS
The UMR-106 cells proliferated rapidly in the sham radiation and HMME treatment alone group, but ultrasound-treated cells and HMME-ultrasound-treated cells proliferated slowly. There was a significant difference between HMME-ultrasound treatment and the controls, including ultrasound radiation, HMME treatment alone, and sham radiation (P < .05). TEM showed endoplasmic reticulum and mitochondrial swelling in the ultrasound-treated cells, and more cells presented apoptosis and necrosis after treatment with ultrasound and HMME together. Intracellular ROS and Ca(2+) in the cells increased more significantly after both ultrasound and HMME treatment than after ultrasound treatment alone.


CONCLUSIONS
HMME could effectively enhance the inhibition effect of ultrasound on osteosarcoma cells. Intracellular ROS and Ca(2+) in the UMR-106 cells increased more significantly after the treatment of HMME and ultrasound together, indicating that the enhancement of HMME on ultrasound cytotoxicity to osteosarcoma cells possibly involves both intracellular ROS and Ca(2+) elevation.
Tian
Zedan
Z
Department of Anesthesiology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China.
Quan
Xuemou
X
Leung
Albert Wingnang
AW
Xiang
Junyan
J
Xu
Chuanshan
C
D001859:Bone Neoplasms / Q000378:metabolism / Q000473:pathology / Q000628:therapy* / Q000648:ultrastructure; D002118:Calcium / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects / Q000528:radiation effects; D006415:Hematoporphyrins / Q000494:pharmacology*; D006801:Humans; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D007477:Ions / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D012516:Osteosarcoma / Q000378:metabolism / Q000473:pathology / Q000628:therapy* / Q000648:ultrastructure; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology; D000078702:Radiofrequency Therapy; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014464:Ultrasonic Therapy / Q000379:methods; D015854:Up-Regulation / Q000187:drug effects
D006415:Hematoporphyrins; D007477:Ions; D011838:Radiation-Sensitizing Agents; D017382:Reactive Oxygen Species; C494379:hematoporphyrin monomethyl ether; D002118:Calcium