Enhancement of radiation effect using beta-lapachone and underlying mechanism

Beta-lapachone (beta-Lap; 3,4-dihydro-2, 2-dimethyl-2H-naphthol[1, 2-b]pyran-5,6-dione) is a novel anti-cancer drug under phase I/II clinical trials. beta-Lap has been demonstrated to cause apoptotic and necrotic death in a variety of human cancer cells in vitro and in vivo. The mechanisms underlying the beta-Lap toxicity against cancer cells has been controversial. The most recent view is that beta-Lap, which is a quinone compound, undergoes two-electron reduction to hydroquinone form utilizing NAD(P)H or NADH as electron source. This two-electron reduction of beta-Lap is mediated by NAD(P)H:quinone oxidoreductase (NQO1), which is known to mediate the reduction of many quinone compounds. The hydroquinone forms of beta-Lap then spontaneously oxidizes back to the original oxidized beta-Lap, creating futile cycling between the oxidized and reduced forms of beta-Lap. It is proposed that the futile recycling between oxidized and reduced forms of beta-Lap leads to two distinct cell death pathways. First one is that the two-electron reduced beta-Lap is converted first to one-electron reduced beta-Lap, i.e., semiquinone beta-Lap (SQ).- causing production of reactive oxygen species (ROS), which then causes apoptotic cell death. The second mechanism is that severe depletion of NAD(P)H and NADH as a result of futile cycling between the quinone and hydroquinone forms of beta-Lap causes severe disturbance in cellular metabolism leading to apoptosis and necrosis. The relative importance of the aforementioned two mechanisms, i.e., generation of ROS or depletion of NAD(P)H/NADH, may vary depending on cell type and environment. Importantly, the NQO1 level in cancer cells has been found to be higher than that in normal cells indicating that beta-Lap may be preferentially toxic to cancer cells relative to non-cancer cells. The cellular level of NQO1 has been found to be significantly increased by divergent physical and chemical stresses including ionizing radiation. Recent reports clearly demonstrated that beta-Lap and ionizing radiation kill cancer cells in a synergistic manner. Indications are that irradiation of cancer cells causes long-lasting elevation of NQO1, thereby sensitizing the cells to beta-Lap. In addition, beta-Lap has been shown to inhibit the repair of sublethal radiation damage. Treating experimental tumors growing in the legs of mice with irradiation and intraperitoneal injection of beta-Lap suppressed the growth of the tumors in a manner more than additive. Collectively, beta-Lap is a potentially useful anti-cancer drug, particularly in combination with radiotherapy.

Treatment of crown-root fracture with a modified crown fragment reattachment technique / 대한치과보존학회지

The development of adhesive dentistry has allowed that the crown fragment reattachment can be another option in the treatment of crown fracture. However, additional crown lengthening procedure or extrusion of the tooth may be necessary in the treatment of crown root fracture because subgingival fracture line in close proximity to the alveolar bone leads to challenges for restorative procedure and the violation of the biologic width. This case report presents a modified crown fragment reattachment technique of crown root fracture with pulp exposure, which was done without additional crown lengthening procedures. After the endodontic treatment, the patient was treated using a post insertion and the fragment reattachment technique, which made it possible to preserve the space for the biologic width and maintain a dry surgical field for adequate adhesion through the modification of the fractured coronal fragment. Since a coronal fracture was occurred and reattached afterward, it was observed that the coronal fragment was well maintained without the additional loss of periodontal attachment through 2-year follow up.

beta-Lapachone suppresses radiation-induced activation of nuclear factor-kappaB

Anticancer effects of beta-lapachone (beta-lap) are due to generation of ROS and metabolic catastrophes as a result of NAD(P)H:quinone oxidoreductase (NQO1)-mediated futile cycling between the oxidized and reduced forms of beta-lap. It has been shown that NQO1 is also essential for the TNF-induced activation of NF-kappaB and that beta-lap suppresses the TNF-induced NF-kappaB activation. We investigated whether or not NQO1 is involved and beta-lap suppresses the radiation-induced NF-kappaB activation using A549 human lung cancer cells and NQO1-knock down A549 cells (shNQO1 A549 cells). Irradiation with 4 Gy markedly increased the DNA binding activity of NF-kappaB in A549 cells, but not in the shNQO1 A549 cells, thus demonstrating that NQO1 plays a pivotal role in irradiation-induced NF-kappaB activation. Treatment with 10 micrometer beta-lap for 4 h almost completely abrogated the radiation-induced increase in NF-kappaB activation and the transcription of NF-kappaB target genes such as bcl2, gadd45beta and cyclinD1. Moreover, beta-lap markedly suppressed the activation of IkappaB kinase gamma (IKKgamma) and the subsequent phosphorylation of IkappaBalpha, thereby inhibiting NF-kappaB activation. It is concluded that beta-lap suppresses the radiation-induced activation of NF-kappaB by interrupting the involvement of NQO1 in the activation of NF-kappaB, thereby inhibiting the transcription of survival signals. The radiosensitization caused by beta-lap may, in part, be attributed to beta-lap-induced suppression of NF-kappaB activation.

The Expression of Oncogenes on the Radiation-induced Apoptosis in SCK Mammary Adenocarcinoma Cell Line / 대한방사선종양학회지

PURPOSE:The expression of p53, p21/WAF/CIP, Bcl-2, and Bax underlying the radiation-induced apoptosis in different pH environments using SCK mammary adenocarcinoma cell line was investigated. MATERIALS AND METHODS: Mammary adenocarcinoma cells of A/J mice (SCK cells) in exponential growth phase were irradiated with a linear accelerator at room temperature. The cells were irradiated with 12 Gy and one hour later, the media was replaced with fresh media at a different pHs. After incubation at 37 degrees C for 0-48 h, the extent of apoptosis was determined using agarose gel electrophoresis and flow cytometry. The progression of cells through the cell cycle after irradiation in different pHs was also determined with flow cytometry. Western blot analysis was used to monitor p53, p21/WAF/CIP, Bcl-2, and Bax protein levels. RESULTS:The induction of apoptosis by irradiation in pH 6.6 medium was markedly less than that in pH 7.5 medium. The radiation-induced G2/M arrest in pH 6.6 medium lasted markedly longer than that in pH 7.5 medium. Considerable amounts of p53 and p21 proteins already existed at pH 7.5 and increased the level of p53 and p21 significantly after 12 Gy X-irradiation. An incubation at pH 6.6 after 12 Gy X-irradiation did not change the level of p53 and p21 protein levels significantly. Bcl-2 proteins were not significantly affected by radiation and showed no correlation with cell susceptibility to radiation-induced apoptosis in different pHs. An exposure to 12 Gy of X-rays increased the level of Bax protein at pH 7.5 but at pH 6.6, it was slight. CONCLUSION: The molecular mechanism underlying radiation-induced apoptosis in different pH environments using SCK mammary adenocarcinoma cell line was dependent of the expression p53 and p21/WAF/CIP proteins. We may propose following hypothesis that an acidic stress augments the radiation-induced G2/M arrest, which inhibiting the irradiated cells undergo post-mitotic apoptosis. The effects of environmental acidity on anti-apoptotic and pro-apoptotic function of Bcl-2 family was unclear in SCK mammary adenocarcinoma cell line.

The Cell Cycle Dependence and Radiation-induced Apoptosis in SCK Mammary Adenocarcinoma Cell Line / 대한방사선종양학회지

PURPOSE: The relationship between environmental pH on the radiation induced-apoptosis in SCK mammary adenocarcinoma cells and cell cycle dependence was investigated. MATERIAL AND METHODS: Mammary adenocarcinoma cells of A/J mice (SCK cells) in exponential growth phase were irradiated with a 137Cs irradiator at room temperature. The cells were irradiated 1 hour after the media was replaced with fresh media at a different pHs. After incubation at 37degrees C for 0-48 h, the extent of apoptosis was determined using agarose gel electrophoresis and flow cytometry. The progression of cells through the cell cycle after irradiation in different pHs was also determined with flow cytometry. RESULTS: The induction of apoptosis by irradiation in pH 6.6 medium was markedly less than that in pH 7.5 medium. When the cells were irradiated and maintained in pH 7.5 medium, the percentage of cells in G2/M phase rapidly increased to about 70% at 12 h after an exposure to 12Gy and returned to control level by 36 h. The percentage of cells in G1 phase decreased as the percentage of cells in G2/M increased. On the other hand, in pH 6.6 medium the percentage of cells in G2/M phases gradually increased to about 45% at 24 h after 12Gy irradiation and then slowly recessed and consequently, as much as 30-35% of the cells were still in the G2/M phase 48 h after irradiation. The percentage of cells in G1 phase then increased as the G2/M arrest began to recede. The radiation-induced G2/M arrest in pH 6.6 medium lasted markedly longer than that in pH 7.5 medium. CONCLUSION: Radiation-induced apoptosis in SCK tumor cells are reversely suppressed in an acidic environment. Radiation-induced G2/M arrest is prolonged in an acidic environment indicating that the suppression of radiation- induced apoptosis and prolongation of radiation-induced G2/M arrest in an acidic environment are related.

The Cell Cycle Dependence and Radiation-induced Apoptosis in SCK Mammary Adenocarcinoma Cell Line / 대한방사선종양학회지

PURPOSE: The relationship between environmental pH on the radiation induced-apoptosis in SCK mammary adenocarcinoma cells and cell cycle dependence was investigated. MATERIAL AND METHODS: Mammary adenocarcinoma cells of A/J mice (SCK cells) in exponential growth phase were irradiated with a 137Cs irradiator at room temperature. The cells were irradiated 1 hour after the media was replaced with fresh media at a different pHs. After incubation at 37degrees C for 0-48 h, the extent of apoptosis was determined using agarose gel electrophoresis and flow cytometry. The progression of cells through the cell cycle after irradiation in different pHs was also determined with flow cytometry. RESULTS: The induction of apoptosis by irradiation in pH 6.6 medium was markedly less than that in pH 7.5 medium. When the cells were irradiated and maintained in pH 7.5 medium, the percentage of cells in G2/M phase rapidly increased to about 70% at 12 h after an exposure to 12Gy and returned to control level by 36 h. The percentage of cells in G1 phase decreased as the percentage of cells in G2/M increased. On the other hand, in pH 6.6 medium the percentage of cells in G2/M phases gradually increased to about 45% at 24 h after 12Gy irradiation and then slowly recessed and consequently, as much as 30-35% of the cells were still in the G2/M phase 48 h after irradiation. The percentage of cells in G1 phase then increased as the G2/M arrest began to recede. The radiation-induced G2/M arrest in pH 6.6 medium lasted markedly longer than that in pH 7.5 medium. CONCLUSION: Radiation-induced apoptosis in SCK tumor cells are reversely suppressed in an acidic environment. Radiation-induced G2/M arrest is prolonged in an acidic environment indicating that the suppression of radiation- induced apoptosis and prolongation of radiation-induced G2/M arrest in an acidic environment are related.

Effect of Increased Intracellular pH by HMA on the Cytotoxicity of Combined Treatment of Hyperthermia and Chemotherapy / 대한치료방사선과학회지

PURPOSE: The enhanced cytotoxic effect of combined treatement of hyperthermia and chemotherapy by increasing intracellular acidify with HMA was investigated. MATERIALS AND METHODS: Fsall tumor cells were injected on the hindlegs of female C3H mice. When the tumor volume reached about 200mm3 , experiments were performed on the groups classified as follows : Group I : Control Group II : Melphalan alone (2.5 mg/kg, 5 mg/kg, 10 mg/kg, 15 mg/kg). Group III : Heat alone (42.5degree C for 1 hour) Group IV : Melphalan + Heat (42.5degree C for 1 hour) Group V : HMA(10 mg/kg) + Melphalan (5.0 mg/kg) + Heat (42.5degree C for 1 hour) Each group included 8-12 mice on each experiment. HMA (3-amino-6-chloro-5(1-homopiperidyl)-N-(diaminomethylene)-c-pyrazinecarboxamide), an analog of amiloride which increases intracellular pH(pHi) was dissolved in dimethyl sulfoxide(DMS) and injected into the tumor-bearing mice through the tail vein. 10mg/kg of HMA and each dose of melphalan were injected into peritoneum of the tumor-bearing mice 30 minutes before heating. Tumor growth delay was calculated when the tumor vlme reached at 1500mm3 . Excision assay was performed on each group and repeated 2-4 times. RESULTS: Tumor growth delay of each experimental groups at 1500 mm3 were 9, 10, 13 and 19 days respectively. In vivo-in vitro excision assay using Fsall tumor cells, the cytotoxicity of each experimental groups was 1.2 X 107 , 1 X 107 , 6 X 106 , 1.7 X 106 and 1 X 105 clonogenic cells/gm respectively. When HMA was added to the combined treatment of heat and chemotherapy, the tumor growth ws delayed more than combined treatment without HMA i.e., 6 days tumor growth delay at 1500 mm3 of tumor volume. CONCLUSION: he combined effect of cytotoxicity by heat and chemotherapy can be much more enhanced by HMA.

Antitumor effect of Ganoderma lucidum: Cytotoxicity and Tumor Growth Delay(1) / 대한치료방사선과학회지

PURPOSE: To investigate the effect of aqueous extract of Ganoderma lucidum(G.I.) on the survival of tumor cells in vitro and on the growth of tumors in vivo. MATERIALS AND METHODS: Dried G.I. was made into powder, extracted with distilled water, filtered and diluted from a maximum concentration of 100 mg/ml in sequence. The cytotoxicity of G.O. in vitro was evaluated from its ability to reduce the clonogenicity of SCK tumor cells. For the tumor growth delay study, about 2' 105 of SCK tumor cells were subcutaneously inoculated in the legs of A/J mice. The first experimental group of mice were injected i.p. with 0.2ml of 250 mg/kg of G/I. From the first day after tumor inoculation for 10 days. The second experimental group of mice were injected i.p. with 0.2ml of 250 mg/kg of G.I. either once a day for 10 days or twice a day for 5 days beginning from the 7th day after tumor inoculation. RESULTS: 1. Cytotoxicity in vitro; survival fraction, as judged from the curve, at G.I. concentration of 0.5,1,5,10,25,50 and 100 mg/ml were 1.0, 0.74+/-0.03, 0.18+/-0.03, 0.15+/-0.02, 0.006+/-0.002, 0.015 and 0.0015, respectively. 2. Tumor growth delay in vivo; a) the time required for the mean tumor volume to grow to 1,000mm3 was 11 days in the control group and 14 days in the experimental group. b) the time required for tumor volume to increase 4 times was 11 days in the control group while it was 10.5 and 12 days in the groups injected with G.I. once a day and twice a day from the 7th day after tumor inoculation respectively. CONCLUSION: Aqueous extracts of G.I. showed a marked cytotoxicity on the SCK mammary cells in vitro. Tumor growth delay was statistically significant when G.I. injection was started soon after tumor inoculation, but it was not significant when injection was started after the tumors were firmly established.

A Case of McArdle's Disease

McArdle's disease is a disorder of carbohydrate metabolism, which is inhented as an autosomal recessive or occasionally an autosomal dominant trait. Hallmark of clinical features is exercise intolerence, I.e. muscle pain following strenuous exercise. Electrophysiologically insertion of an EMG needle shows that there is no electrical activity, differentiating this contracture from a muscle cramp. Histological examination of muscle biopsy specimen shows increase in glycogen and the presence of subsarcolemrnal blebs. We report a 23-year-old, male patient who presented clinical, electrophysiological, and histological findings compatible with McArdle's disease.

A Case of Multiple Mononeuropathy Associated with Polyarteritis Nodosa

Polyarteritis nodosa(PAN) has been depicted as a necrotizing arteritis of small and medium-sized muscular arteries, affecting multiple organ systems throughout the body. The etiology of PAN remains unknown, but the histopathologic resemblance to chronic serim sickness has suggested an immune complex pathogenesis. The peripheral nervous system(PNS) is more frequently affected (in about 20-50% of patients) than the central nervous system(in about 10-20% of patients). Although multiple mononeuritis multiplex is generally considered to be the typical PNS manifestation of PAN, distal symmetrical polyneuropathy may occur more frequently than previous recognized. We report a case of polyarteritis nodosa with mononeuritis multiplex and distal symmetrical polyneuropathy, which was diagnosed by electrophysiological study and biopsies of muscle and sural nerve.

A Case of Suspected Hallervorden-Spatz Disease

Hallervorden-Spatz disease is a rare, autosomal recessive disorder of mainly early childhood which is characterized by pigmentary degeneration of the globus pallidus, substantia nigra, and red nucleus. Clinically it manifests various symptoms and signs of extrapyramidal and pyramidal involvement. Authors report a 28-year-old female patient with suspected Hallervorden-Spatz disease in the aspects of clinical and MRI findings suggesting metal deposition in the globus pallidus, substantia nigra, and red nucleus on both side.

A Case of Hemiballism

Hemiballism is a ballistic, involuntary movement disorder, usually of a sudden onset, an often occurs due to encephalomalasic lesion, mostly an infarction, of deep structure of contralateral cerebral hemisphere, rarely by a small hemorrhage. The lesion site is thought to be mainly subthalamic nucleus contralateral to the abnormal movement. But there have been several reports on hemiballism without involvement of subthalmic nucleus throughout the world. We report a case of acute vascular hemiballism occurred due to a small hemorrhage with involvement of left putamen and globus pallidus, which was demonstrated by computed tomography and magnetic resonance imaging study of brain.

Findings of repetitive nerve stimulation test in myasthenia gravis: A case-control study

Authors had perforrned repetitive nerve stimulation tests on orbicularis oculi, flexor carpi ulnaris, and abductor digiti quinti muscles in 21 myasthenic patients and 40 normal controls using conventional Oh's rnethod and analysed statistically in detail. The results were as follows: 1) There were no significant statistical differences in CMAP and postexercise potentiation between normal controls and myastheic patients, but there were statistically significant decremental responses in both low-and high-rate of stimulation in myasthenic patients, with characteristic posttetanic potentiation and posttetanic exhaustion. 2) There were no statistical differences among Desmedt's, Stalberg's, and Oh's methods in determining the decremental ratio in low-rate of stimulation. 3) The proximal muscles showed more prominent decremental responses than distal muscles in myasthenic patients, and in three myasthenic patients, (14.3%) there were no statistically significant decremental responses in all tested muscles in spite of postivie edrophonium responses. 4) The gerleralized type myasthenic patients showed more prominent decremental responses than oclular type myasthenic patients. 5) Among the myasthenic patients, the oclular type myasthenic patients showed no statistically significant decremental response in both low-and high-rate of stimulation performed on flexor carpi ulnaris and abductor digiti quinti muscles.

A Case of Tuberculous Brain Abscess

Tuberculous brain abscess, an unusual complication of tuberculosis, has been rarely reported worldwide.It should be differentiated from tuberculomas of the brain and pyogenic brain abscess, but on the basis of clinical, laboratory, and roentgenographic information the differential diagnosis is difficult and only pathological plus bacteriological evidence can suffice it. We report a case of tuberculous brain abscess developed during antituberculous therapy in 20-year-old girl who had been suffered from pulmonary tuberculosis and tuberculous meningitis.