Apoptosis induction by aluminum phthalocyanine tetrasulfonate-based sonodynamic therapy in HL-60 cells

Abstract

The present study aims to investigate sonodynamically-induced apoptosis using the phthalocyanine, chloroaluminum phthalocyanine tetrasulfonate (AlPcTS). HL-60 cells were exposed to ultrasound for up to 3 min in the absence and presence of AlPcTS. Apoptosis was analyzed by cell morphology, DNA fragmentation, and caspase-3 activity. Electron spin resonance was used to measure reactive oxygen species. The number of apoptotic cells showing membrane blebbing and cell shrinkage after combined treatment (ultrasound and AlPcTS) was significantly higher than following other treatments, including ultrasound alone and AlPcTS alone. Furthermore, DNA ladder formation, caspase-3 activation and enhanced nitroxide generation were observed in cells treated with ultrasound and AlPcTS. Sonodynamically induced apoptosis, caspase-3 activation, and nitroxide generation were significantly suppressed by histidine. The significant reduction by histidine indicated that ultrasonically generated reactive oxygen species, such as singlet oxygen, is an important mediator of sonodynamically-induced apoptosis.

Apoptosis Induced by Ultraviolet A Exposure in the Presence of Enoxacin in HL-60 Cells

“…The fragmentation of DNA at linker regions between nucleosomes into fragments of multiples of 180-200 base pairs in length is reported to be a hallmark of apoptosis (31)(32)(33). In this study, enoxacin plus UVA treatment resulted in the formation of a characteristic DNA ladder on agarose gel electrophoresis.…”

“…In the pathogenesis of various skin diseases, a number of signalling pathways are activated as a result of UVA-mediated ROS generation. ROS are believed to activate proliferative and cell survival signalling that can alter the apoptotic pathways involved in the pathogenesis of a number of skin disorders, including photosensitivity (30)(31)(32)(33)(34)(35)(36).…”

“…The culture samples treated with enoxacin alone were placed in the same position for the same period as cells were exposed to UVA. After treatment, HL-60 cells were once again incubated in a humidified atmosphere of 5% CO 2 at 37˚C (30,31) and analysed as described below.…”

“…The integrity of intact cells was also examined immediately prior to each series of treatments, with cell suspensions exhibiting >99% integrity being used in the experiments. The proportion of total sampled cells to intact cells before treatment was used as the baseline for the integrity determination (31).…”

Antitumor effect of sonodynamically activated pyrrolidine tris-acid fullerene

“…Ultrasound has a tissue attenuation coefficient appropriate for penetrating intervening tissues to reach non-superficial objects while maintaining the ability to focus energy into small volumes. Sonodynamic therapy is a new and promising strategy for cancer treatment based on the generation of reactive oxygen species during irradiation by ultrasound in the presence of sonosensitizers selectively accumulated in the malignant target tissue [1][2][3][4].…”