A Novel Chenodeoxycholic Derivative HS-1200 Induces Apoptosis in Human HT-29 Colon Cancer Cells / 대한방사선종양학회지

PURPOSE: To investigate the growth inhibitory effects, and the underlying mechanism of human colon cancer cell (HT-29) death, induced by a new synthetic bile acid derivative (HS-1200). MATERIALS AND METHODS: Human colon cancer cells (HT-29), in exponential growth phase, were treated with various concentrations of a new synthetic bile acid derivative (HS-1200). The growth inhibitory effects on HT-29 cells were examined using a trypan blue exclusion assay. The extent of apoptosis was determined using agarose gel electrophoresis, TUNEL assays and Hoechst staining. The apoptotic cell death was also confirmed by Western blotting of PARP, caspase-3 and DNA fragmentation factor (DFF) analysis. To investigate the involvement of mitochondria, we employed immunofluorescent staining of cytochrome c and mitochondrial membrane potential analyses. RESULTS: The dose required for the half maximal inhibition (IC50) of the HT-29 cell growth was 100~150 micro M of HS-1200. Several changes, associated with the apoptosis of the HT-29 cells, were reveal by the agarose gel eletrophoresis, TUNEL assays and Hoechst staining, following their treatment with 100 micro M of HS-1200. HS-1200 treatment also induced caspase-3, PARP and DFF degradations, and the western blotting showed the processed caspase-3 p20, PARP p85 and DFF p30 and p11 cleaved products. Mitochondrial events were also demonstrated. The cytochrome c staining indicated that cytochrome c had been released from the mitochondria in the HS-1200 treated cells. The mitochondrial membrane potential (deltaxm) was also prominently decreased in the HS-1200 treated cells. CONCLUSION: These findings suggest that the HS-1200 - induced apoptosis of human colon cancer cells (HT-29) is mediated via caspase and mitochondrial pathways.

Combined Modality Therapy with Selective Bladder Preservation for Muscle Invading Bladder Cancer / 대한방사선종양학회지

PURPOSE: To assess the tolerance, complete response rate, bladder preservation rate and survival rate in patients with muscle-invading bladder cancer treated with selective bladder preservation protocol. METHOD AND MATERIALS: From October 1990 to June 1998, twenty six patients with muscle-invading bladder cancer (clinical stage T2-4, N0-3, M0) were enrolled for the treatment protocol of bladder preservation. They were treated with maximal TURBT (transurethral resection of bladder tumor) and 2 cycles of MCV chemotherapy (methotrexate, crisplatin, and vinblastine) followed by 39.6~45 Gy pelvic irradiation with concomitant cisplatin. After complete urologic evaluation (biopsy or cytology), the patients who achieved complete response were planed for bladder preservation treatment and treated with consolidation cisplatin and radiotherapy (19.8 Gy). The patients who had incomplete response were planed to immediate radical cystectomy. If they refused radical cystectomy, they were treated either with TURBT followed by MCV or cisplatin chemotherapy and radiotherapy. The median follow-up duration is 49.5 months. RESULT: The patients with stage T2-3a and T3b-4a underwent complete removal of tumor or gross tumor removal by TURBT, respectively. Twenty one out of 26 patients (81%) successfully completed the protocol of the planned chemo-radiotherapy. Seven patients had documented complete response. Six of them were treated with additional consolidation cisplatin and radiotherapy. One patient was treated with 2 cycles of MCV chemotherapy due to refusal of chemo-radiotherapy. Five of 7 complete responders had functioning tumor-free bladder. Fourteen patients of incomplete responders were further treated with one of the followings : radical cystectomy (1 patient), or TURBT and 2 cycles of MCV chemotherapy (3 patients), or cisplatin and radiotherapy (10 patients). Thirteen patients of them were not treated with planned radical cystectomy due to patients' refusal (9 patients) or underlying medical problems (4 patients). Among twenty one patients, 12 patients (58%) were alive with their preserved bladder, 8 patients died with the disease, 1 patient died of intercurrent disease. The 5 years actuarial survival rates according to CR and PR after MCV chemotherapy and cisplatin chemoradiotherapy were 80% and 14%, respectively (p=0.001). CONCLUSION: In selected patients with muscle-invading bladder cancer, the bladder preservation could be achieved by MCV chemotherapy and cisplatin chemo-radiotherapy. All patients tolerated well this bladder preservation protoco. The availability of complete TURBT and the responsibility of neoadjuvant chemotherapy and chemoradiotherapy were important predictors for bladder preservation and survival. The patients who had not achieved complete response after neoadjuvant chemotherapy and chemoradiotherapy should be immediate radical cystectomy. A randomized prospective trial might be essential to determine more accurate indications between cystectomy or bladder preservation.

Smad6 Gene and Suppression of Radiation-Induced Apoptosis by Genistein in K562 cells / 대한방사선종양학회지

PURPOSE: The genes involved on the suppression of radiation-induced apoptosis by genistein in K562 leukemia cell line was investigated. MATERIALS AND METHODS: K562 cells in exponential growth phase were irradiated with a linear accelerator at room temperature. Forx-ray irradiation and drug treatment, cultures were prepared at 2x105 cells/mL. The cells were irradiated with 10 Gy (Clinac 1800C, Varian, USA). Stock solutions of herbimycin A (HMA, Calbiochem, UK) and genistein (Calbiochem, UK) were prepared in dimethylsulfoxide (DMSO, Sigma, UK). After incubation at 37degreesC for 24 h, PCR-select cDNA subtractive hybridization, dot hybridization, DNA sequencing and Northern hybridization were examined. RESULTS: Smad6 gene was identified from the differentially expressed genes in K562 cells incubated with genistein which had been selected by PCR-select cDNA subtractive hybridization. The mRNA expression of Smad6 in K562 cells incubated with genistein was also higher than control group by Northern hybridization analysis. CONCLUSION: We have shown that Smad6 involved on the suppression of radiation-induced apoptosis by genistein in K562 leukemia cell line. It is plausible that the relationship between Smad6 and the suppression of radiation-induced apoptosis is essential for treatment development based on molecular targeting designed to modify radiation-induced apoptosis.

The Measurements of Plasma Cytokines in Radiation-induced Pneumonitis in Lung Cancer Patients / 대한방사선종양학회지

PURPOSE: To investigate whether changes in plasma concentrations of transforming growth factor-beta1 (TGF-beta1), tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) could be used to identify the development of radiation-induced pneumonitis in the lung cancer patients. METHODS AND MATERIALS: Seventeen patients with lung cancer (11 NSCLC, 6 SCLC) were enrolled in a prospective study designed to evaluate clinical and molecular biologic correlation of radiation-induced pneumonitis. The study began in May 1998 and completed in July 1999. All patients were treated with radiotherapy with curative intent : 1.8 Gy per day, 5 fractions per week. Serial measurements of plasma TGF-beta1, TNF-alpha and IL-6 were obtained in all patients before, weekly during radiotherapy and at each follow-up visits after completion of treatment. These measurements were quantified using enzyme linked immunosorbent assay (ELISA). All patients were evaluated for signs and symptoms of pneumonitis at each follow-up visit after completion of radiotherapy. High resolution CT (HRCT) scans were obtained when signs and symptoms of pneumonitis were developed after completion of radiotherapy. RESULTS: Thirteen patients eventually developed signs and symptoms of clinical pneumonitis while four patients did not. TGF-beta1 levels were elevated in all 13 patients with pneumonitis, which showed characteristic pattern of elevation (38.45 ng/ml at pretreatment, 13.66 ng/ml during radiotherapy, then 60.63 ng/ml at 2-4 weeks after completion of radiotherapy). The levels of TNF-alpha and IL-6 were also elevated in the group of patients who developed pneumonitis but the pattern was not characteristic. CONCLUSIONS: Changes in plasma TGFbeta-1 levels before, during and after radiotherapy appears to be a useful means by which to identify patients at risk for the development of symptomatic pneumonitis. Other cytokines like TNF-alpha and IL-6 shows no meaningful changes in association with radiation pneumonitis.