Lee KB, Lee JS, Park JW, Huh TL, Lee YM. Low energy proton beam induces tumor cell apoptosis through reactive oxygen species and activation of caspases. Exp Mol Med ;

School of Life Sciences and Biotechnology, College of Natural Sciences, Kyungpook National University, Daegu 702-701, Korea.
Experimental and Molecular Medicine (Impact Factor: 3.45). 03/2008; 40(1):118-29. DOI: 10.3858/emm.2008.40.1.118
Source: PubMed


Proton beam is useful to target tumor tissue sparing normal cells by allowing precise dose only into tumor cells. However, the cellular and molecular mechanisms by which proton beam induces tumor cell death are still undefined. We irradiated three different tumor cells (LLC, HepG2, and Molt-4) with low energy proton beam (35 MeV) with spread out Bragg peak (SOBP) in vitro, and investigated cell death by MTT or CCK-8 assay at 24 h after irradiation. LLC and HepG2 cells were sensitive to proton beam at over 10 Gy to induce apoptosis whereas Molt-4 showed rather low sensitivity. Relative biological effectiveness (RBE) values for the death rate relative to gamma-ray were ranged from 1.1 to 2.3 in LLC and HepG2 but from 0.3 to 0.7 in Molt-4 at 11 d after irradiation by colony formation assay. The typical apoptotic nuclear DNA morphological pattern was observed by staining with 4'-6-diamidino-2-phenylindole (DAPI). Tiny fragmented DNA was observed in HepG2 but not in Molt-4 by the treatment of proton in apoptotic DNA fragment assay. By FACS analysis after stained with FITC-Annexin-V, early as well as median apoptotic fractions were clearly increased by proton treatment. Proton beam-irradiated tumor cells induced a cleavage of poly (ADP-ribose) polymerase-1 (PARP-1) and procaspases-3 and -9. Activity of caspases was highly enhanced after proton beam irradiation. Reactive oxygen species (ROS) were significantly increased and N-acetyl cysteine pretreatment restored the apoptotic cell death induced by proton beam. Furthermore, p38 and JNK but not ERK were activated by proton and dominant negative mutants of p38 and JNK revived proton-induced apoptosis, suggesting that p38 and JNK pathway may be activated through ROS to activate apoptosis. In conclusion, our data clearly showed that single treatment of low energy proton beam with SOBP increased ROS and induced cell death of solid tumor cells (LLC and HepG2) in an apoptotic cell death program by the induction of caspases activities.

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    • "The use of generic RBE means the use of the same RBE in all positions in spread out Bragg peak (SOBP), at all dose levels per fraction and in all tissues. However, application of a single RBE value for protons is complicated because the RBE varies dependent on the energy of the proton [16], the fractionation [17], tissue types [18], oxygenation status [19], and the biological endpoint studied. Though it is widely accepted, a generic RBE cannot be a universal RBE for each tissue or dose/fraction. "
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    ABSTRACT: In the previous review, the physical aspect of heavy particles, with a focus on the carbon beam was introduced. Particle beam therapy has many potential advantages for cancer treatment without increasing severe side effects in normal tissue, these kinds of radiation have different biologic characteristics and have advantages over using conventional photon beam radiation during treatment. The relative biological effectiveness (RBE) is used for many biological, clinical endpoints among different radiation types and is the only convenient way to transfer the clinical experience in radiotherapy with photons to another type of radiation therapy. However, the RBE varies dependent on the energy of the beam, the fractionation, cell types, oxygenation status, and the biological endpoint studied. Thus this review describes the concerns about RBE related to particle beam to increase interests of the Korean radiation oncologists' society.
    03/2012; 30(1):1-13. DOI:10.3857/roj.2012.30.1.1
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    • "Several researchers have shown that ROS related apoptosis is processed by the mitochondrial pathway, through the activation of p38 [73,74,75]. It has been demonstrated that ROS-dependent activation of MAPKs is crucial for mitochondria-mediated apoptosis [76]. "
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    ABSTRACT: Reacytive Oxygen Species (ROS) have long been considered to be involved in the initiation, progression and metastasis of cancer. However, accumulating evidence points to the benefical role of ROS. Moreover, ROS production, leading to apoptosis, is the mechanism by which many chemotherapeutic agents can act. Beside direct actions, ROS elicit lipid peroxidation, leading to the production of 4-hydroxynoneal (HNE). Interestingly, HNE also seems to have a dual behaviour with respect to cancer. In this review we present recent literature data which outline the "two-faced" character of oxidative stress and lipid peroxidation in carcinogenesis and in the hallmarks of cancer.
    Cancers 06/2010; 2(2):338-363. DOI:10.3390/cancers2020338
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    • "Apoptosis-mediated cell death was examined as described (Lee et al., 2008) with minor modifications. In brief, MCF-7 cells were seeded onto chamber slides at a density of 5 × 10 4 cells per well and then treated with 1 mM soy peptide dissolved in RPMI 1640 medium for 24 h. "
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    ABSTRACT: During carcinogenesis, NF-gammaB mediates processes associated with deregulation of the normal control of proliferation, angiogenesis, and metastasis. Thus, suppression of NF-gammaB has been linked with chemoprevention of cancer. Accumulating findings reveal that heat shock protein 90 (HSP90) is a molecular chaperone and a component of the IgammaB kinase (IKK) complex that plays a central role in NF-gammaB activation. HSP90 also stabilizes key proteins involved in cell cycle control and apoptosis signaling. We have determined whether the exogenous administration of isoflavone-deprived soy peptide prevents 7,12-dimethylbenz[alpha]anthracene (DMBA)-induced rat mammary tumorigenesis and investigated the mechanism of action. Dietary administration of soy peptide (3.3 g/rat/day) significantly reduced the incidence of ductal carcinomas (50%), the number of tumors per multiple tumor-bearing rats (49%; P<0.05), and extended the latency period of tumor development (8.07+/-0.92 weeks) compared to control diet animals (10.80+/-1.30; P<0.05). Our results have further demonstrated that soy peptide (1) dramatically inhibits the expression of HSP90, thereby suppressing signaling pathway leading to NF-gammaB activation; (2) induces expression of p21, p53, and caspase-3 proteins; and (3) inhibits expression of VEGF. In agreement with our in vivo data, soy peptide treatment inhibited the growth of human breast MCF-7 tumor cells in a dose-dependent manner and induced apoptosis. Taken together, our in vivo and in vitro results suggest chemopreventive and tumor suppressive functions of isoflavone-deprived soy peptide by inducing growth arrest and apoptosis.
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