Tag: Apoptosis

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Enhancement of antitumor activity by using 5-ALA–mediated sonodynamic therapy to induce apoptosis in malignant gliomas

J Neurosurg 129:1416–1428, 2018

High invasiveness of malignant gliomas frequently causes early local recurrence of the tumor, resulting in extremely poor outcome. To control such recurrence, novel therapies targeted toward infiltrating glioma cells around the tumor border are required. Here, the authors investigated the antitumor activity of sonodynamic therapy (SDT) combined with a sonosensitizer, 5-aminolevulinic acid (5-ALA), on malignant gliomas to explore the possibility for clinical use of 5-ALA–mediated SDT (5-ALA-SDT).

METHODS In vitro cytotoxicity of 5-ALA-SDT was evaluated in U87 and U251 glioma cells and in U251Oct-3/4 glioma stemlike cells. Treatment-related apoptosis was analyzed using flow cytometry and TUNEL staining. Intracellular reactive oxygen species (ROS) were measured and the role of ROS in treatment-related cytotoxicity was examined by analysis of the effect of pretreatment with the radical scavenger edaravone. Effects of 5-ALA-SDT with high-intensity focused ultrasound (HIFU) on tumor growth, survival of glioma-transplanted mice, and histological features of the mouse brains were investigated.

RESULTS The 5-ALA-SDT inhibited cell growth and changed cell morphology, inducing cell shrinkage, vacuolization, and swelling. Flow cytometric analysis and TUNEL staining indicated that 5-ALA-SDT induced apoptotic cell death in all gliomas. The 5-ALA-SDT generated significantly higher ROS than in the control group, and inhibition of ROS generation by edaravone completely eliminated the cytotoxic effects of 5-ALA-SDT. In the in vivo study, 5-ALA-SDT with HIFU greatly prolonged survival of the tumor-bearing mice compared with that of the control group (p < 0.05). Histologically, 5-ALA-SDT produced mainly necrosis of the tumor tissue in the focus area and induced apoptosis of the tumor cells in the perifocus area around the target of the HIFU-irradiated field. The proliferative activity of the entire tumor was markedly decreased. Normal brain tissues around the ultrasonic irradiation field of HIFU remained intact.

CONCLUSIONS The 5-ALA-SDT was cytotoxic toward malignant gliomas. Generation of ROS by the SDT was thought to promote apoptosis of glioma cells. The 5-ALA-SDT with HIFU induced tumor necrosis in the focus area and apoptosis in the perifocus area of the HIFU-irradiated field, whereas the surrounding brain tissue remained normal, resulting in longer survival of the HIFU-treated mice compared with that of untreated mice. These results suggest that 5-ALA-SDT with HIFU may present a less invasive and tumor-specific therapy, not only for a tumor mass but also for infiltrating tumor cells in malignant gliomas.

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Intracellular Signaling Pathways and Size, Shape, and Rupture History of Human Intracranial Aneurysms

Neurosurgery 70:1565–1573, 2012 DOI: 10.1227/NEU.0b013e31824c057e

Size and morphological features are associated with intracranial aneurysm (IA) rupture. The cellular mechanisms of IA development and rupture are poorly known.
OBJECTIVE: We studied the expression and phosphorylation of different intracellular signaling molecules in the IA wall compared with IA morphological features to understand better the cellular pathways involved in IA development and wall degeneration.
METHODS: Nine ruptured and 17 unruptured human IA samples were collected intraoperatively. The expression levels and phosphorylation state of 3 mitogen-activated protein kinases (c-Jun N-terminal kinase [JNK], p38, extracellular signal-regulated kinase [ERK]), Bcl-2 antagonist of cell death (Bad), mammalian target of rapamycin (mTOR), cyclic AMP response element binding protein (CREB), and Akt were determined by Western blotting. The localization of signaling proteins was determined by immunofluorescence. From 3-dimensional segmentation of computed tomography angiographic data, size and shape indexes were calculated.
RESULTS: We found a 5-fold difference in phospho-Bad levels between ruptured and unruptured IAs. Phospho-mTOR was downregulated 2.5-fold in ruptured IAs. Phosphop54 JNK, phospho-p38, and phospho-Akt levels correlated positively with IA size. Phospho-CREB levels were significantly associated with nonsphericity and ellipticity indexes. Phospho-Akt and phospho-p38 correlated negatively with undulation index.
CONCLUSION: The signaling pathway profile (apoptosis, cell proliferation, stress signaling) differs between ruptured and unruptured IAs and is associated with IA geometry. Our results increase the knowledge of IA development and wall degeneration.

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Effect of bupivacaine on intervertebral disc cell viability

The Spine Journal 10 (2010) 159–166

Bupivacaine is a local anesthetic commonly used to relieve or control pain in interventional spine procedures. Bupivacaine has been shown to be toxic to articular cartilage, which has similarities to intervertebral disc (IVD) cartilage, raising concern over a potentially negative effect of bupivacaine on the disc.

PURPOSE: To determine bupivacaine’s effect on cell viability of IVD cells in vitro and to elucidate whether this is through apoptosis or necrosis.

STUDY DESIGN: In vitro controlled study of bupivacaine effect on cell viability in human and rabbit IVD cells.

SUBJECTS: Rabbit annulus fibrosus (AF) tissue, nucleus pulposus (NP) cells, and knee articular chondrocytes were isolated from New Zealand white rabbits. Human AF and NP cells were isolated from stage 3 to 4 degenerative disc surgical specimens.

OUTCOME MEASURES: Cell viability was assessed after exposure to bupivacaine via trypan blue staining or flow cytometry.

METHODS: Annulus fibrosus and NP cells were grown in monolayer and alginate beads, respectively, to simulate their physiologic environment. The cells were then exposed to bupivacaine or saline control at 60 and 120 minutes and examined for cell viability. RESULTS: Rabbit NP cell death demonstrated a time and dose dependence in response to bupivacaine. In addition, cell death was greater than that observed for articular chondrocytes. Rabbit AF tissue also demonstrated increased cell death in response to bupivacaine exposure. Human NP cells demonstrated time-dependent cell death, with greater necrosis than apoptosis. Annulus fibrosus cells grown in monolayers also resulted in similar effects, with greater necrosis rather than apoptosis.

CONCLUSIONS: Despite its pain relieving properties, bupivacaine decreases cell viability in rabbit and human disc cells in a time-dependent manner. In addition, the changes observed are greater than that seen for articular chondrocytes. This increase in cell death appears to be related to an increase in necrosis rather than apoptosis. Whether bupivacaine exerts similar effects in vivo or how this relates to overall clinical outcome remains to be explored.

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