Apoptosis induced by low-intensity ultrasound in vitro: Alteration of protein profile and potential molecular mechanism

Abstract

Abstract. To analyze the potential mechanism related to the apoptosis induced by low intensity focused ultrasound, comparative proteomic method was introduced in the study. After ultrasound irradiation (3.0 W/cm 2 , 1 minute, 6 hours incubation post-irradiation), the human SMMC-7721 hepatocarcinoma cells were stained by trypan blue to detect the morphologic changes, and then the percentage of early apoptosis were tested by the flow cytometry with double staining of FITC-labelled Annexin V/Propidium iodide. Two-dimensional SDS polyacrylamide gel electrophoresis was used to get the protein profile and some proteins differently expressed after ultrasound irradiation were identified by MALDI-TOF mass spectrometry. It's proved early apoptosis of cells were induced by low intentisy focused ultrasound. After ultrasound irradiation, the expressing characteristics of several proteins changed, in which protein p53 and heat shock proteins are associated with apoptosis initiation. It is suggested that the low-intensity ultrasound-induced apoptotic cancer therapy has the potential application via understanding its relevant molecular signaling and key proteins. Moreover, the comparative proteomic method is proved to be useful to supply information about the protein expression to analyze the metabolic processes related to bio-effects of biomedical ultrasound.

Nanoparticle-assisted ultrasound: A special focus on sonodynamic therapy against cancer

“…The same nanoconstruct was studied to deliver oxygen to hypoxic tissues, exploiting the boiling point of the perfluoropentane core (32°C). In fact, whereas this compound is liquid at room temperature, it is in vapour phase at body temperature, leading [155][156][157][158][159][160][161][162][163][164][165][166][167][168][169][170][171][172] to an higher expansion of the nanobubbles and enhancing the release of loaded oxygen molecules under ultrasound irradiation [102]. In addition to liposomes and polymeric NPs, also metallic and inorganic nanoconstructs could represent efficient platforms for carrying sonosensitizer molecules.…”

“…Chemical Engineering Journal 340 (2018) [155][156][157][158][159][160][161][162][163][164][165][166][167][168][169][170][171][172] residual air bubbles inside the silicon nanoporous structure and by the formation of gas (hydrogen) bubbles due to silicon NPs' dissolution [110]. Nevertheless, concerning the class of NPs employed as nanosensitizers in SDT, the most widely studied are titanium dioxide (TiO 2 ) NPs.…”

“…Alternatively, high-energy shock-waves can be used to minimize the temperature effects while increasing the likelihood of cavitation [93]. Indeed, using single acoustic pulses with a wide frequency range (up to 20 MHz) and high-pressure amplitude (up to 120 MPa) [155][156][157][158][159][160][161][162][163][164][165][166][167][168][169][170][171][172] combined with porphyrins-loaded polymeric NPs, Canaparo et al were able to induce sonodynamic therapy effects on an in-vitro neuroblastoma model [99]. As stated above, the inertial cavitation refers to the rapid growth and violent collapse of bubbles after exposure to ultrasound.…”

“…Focusing especially on apoptosis, the association between US and this death process is largely reported in the literature [151][152][153][154][155]. Nevertheless, the precise mechanisms driving this event are nor shared neither completely understood.…”

Upregulation of Beclin-1 expression in DU-145 cells following low-frequency ultrasound irradiation combined with microbubbles

“…Ultrasound has been widely used in cancer therapy and has been shown to mediate apoptosis through thermal, cavitation, sonoporation and sonochemical effects; however, the underlying mechanisms remain unclear (5). Furthermore, a number of experiments indicated that the effects of ultrasound may be enhanced by microbubbles (6,7).…”