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Transcriptional Regulation of H2B Histone Gene Expression by Nocodazole in HL-60 Cells.

Kyu LIM ; Ye Gi HONG ; Myung Sun LEE ; Mee Young SON ; Kyung Ah YUN ; Jong Il PARK ; Wan Hee YOON ; Sung Kiel PARK ; Byung Doo HWANG

Journal of the Korean Cancer Association.2000;32(2):407-416.

PURPOSE: Nocodazole, a microtubule disrupting reagent, is known to arrest cells in the M phase, To gain insight on the regulatory mechanism of H2B histone gene expression by nocodazole in HL-60 cell, the binding pattern of nuclear proteins to cis element in the human H2B histone gene promoter has been investigated with DNase I footprinting and DNA mobility shift assay. MATERIALS AND METHODS: Northern blot hybridization was performed by the method of Virca et al. A Hinc II-Sac I fragment of pSPH28 was used as probe for Northern blot analysis of H2B histone mRNA. DNase I footprinting and DNA mobility shift assay were performed by the method of Lim et al. End labeled DNA oligomer (upper strand, 5'-CTTCACCTTATTTGCATAA GCGATTC-3') for octamer binding activity was mixed with nuclear extracts in a 20 ul reaction volume containing 60 mM KC1, 12 mM HEPES, pH 7.9, 5 mM MgCl2, 0.2 mM EDTA, 0.2 mM DTT, 12% glycerol, and 2 ug of poly [dI-dC]. RESULTS: The level of H2B histone mRNA rapidly was reduced at 24 hours in nocodazole-treated HL-60 cells and the mRNA was repressed in proportion to the concentration of nocodazole. Nocodazole-dependent repression of H2B histone gene was restored by replacement with nocodazole-free media. In DNase I footprinting analysis, one nuclear factor bound at 42 bp site (octamer motif) in the absence of nocodazole. In the presence of nocodazole, the binding of nuclear factor on octamer motif partially vanished. In DNA mobility shift assay, one DNA-protein complex (Octl) was formed when octamer motif was incubated with nuclear extract of HL-60 cell. After nocodazole treatment, Octl binding activity was reduced by time dependent manner. CONCLUSION: These results suggest that nocodazole-dependent repression of H2B histone gene is correlated with reduction of Octl binding activity in HL-60 cell.
Blotting, Northern ; Cell Division ; Deoxyribonuclease I ; DNA ; Edetic Acid ; Electrophoretic Mobility Shift Assay ; Gene Expression* ; Glycerol ; HEPES ; Histones* ; HL-60 Cells* ; Humans ; Hydrogen-Ion Concentration ; Magnesium Chloride ; Microtubules ; Nocodazole* ; Nuclear Proteins ; Repression, Psychology ; RNA, Messenger

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Initial Experience of Fractionated Stereotactic Radiotherapy for Metastatic Brain Tumors.

Moon June CHO ; Ki Hwan KIM ; Ji Young JANG ; Jun Sang KIM ; Seong Ho KIM ; Chang Joon SONG ; Jae Sung KIM

Journal of the Korean Cancer Association.2000;32(2):374-381.

PURPOSE: This study aimed to evaluate the preliminary treatment results of fractionated stereotactic radiotherapy (FSRT) for metastatic brain tumors. MATERIALS AND METHODS: Between August 1997 and December 1998, frameless FSRT was performed in 11 patients with metastatic brain tumor (1S lesions). Primary sites were lung in 7 patients, breast in 2, stomach in 1, and malignant melanoma in 1, All patients received 30-36 Gy/10-20 fx external beam irradiation to whole brain. Eight patients received FSRT for 1 lesion, one for 2 lesions, and two for 4 lesions. Fractionation schedule was 25 Gy/5 fx in 11 lesions, 18 Gy(1 fx in 3, 30 Gy/5 fx in 2, 15 Gy/5 fx in 1. Mean tumor volume was 7.0 cc (0.39~55.23 cc). Multiple-arc FSRT was delivered to 16 lesions and conformal FSRT through irregular ports shaped to tumor profile to 2 lesions. RESULTS: No patient experienced any acute side reaction from FSRT. Follow-up radiologic evaluation was available in 9 patients. Six of nine patients achieved the complete response, but two showed the partial response and one showed no response on follow-up radiologic studies. Among six patients with complete response, 5 patients survived from 5 to 15 months and showed no evidence of metastatic brain d#isease clinically and/or radiologically at last follow-up. Among two patients who did not have radiologic evaluation, one showed clinically complete response until death and the other died just after FSRT caused by intercurrent disease. One patient with no response radiologically survived 7 months and showed nearly complete disappearance of clinical symptom with stable status radiologically, CONCLUSION: Initial experience in this study suggests that the external beam irradiation to whole brain with 30 Gy/10 fx followed by FSRT with 20~30 Gy/5~6 fx could be the good treatment option to the patients with metastatic brain tumor. This study suggests that the fractionation schedule for FSRT should be determined in consideration of performance status, number of metastasis, tumor volume, location, presence of extracranial disease, and age.
Appointments and Schedules ; Brain Neoplasms* ; Brain* ; Breast ; Follow-Up Studies ; Humans ; Lung ; Melanoma ; Neoplasm Metastasis ; Radiotherapy* ; Stomach ; Tumor Burden