T-W Kim

University of Ulsan, Ulsan, Ulsan, South Korea

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Publications (3)18.13 Total impact

  • S-W Hong · S-H Lee · J-H Moon · J J Hwang · D E Kim · E Ko · H-S Kim · I J Cho · J S Kang · D J Kim · [...] · J-S Shin · D-J Jung · Y-J Jeong · B-J Cho · T-W Kim · J S Lee · Y-I Hwang · D-Y Noh · D-H Jin · W J Lee ·
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    ABSTRACT: L-ascorbate (L-ascorbic acid, vitamin C) clearly has an inhibitory effect on cancer cells. However, the mechanism underlying differential sensitivity of cancer cells from same tissue to L-ascorbate is yet to be clarified. Here, we demonstrate that L-ascorbate has a selective killing effect, which is influenced by sodium-dependent vitamin C transporter 2 (SVCT-2) in human breast cancer cells. Treatment of human breast cancer cells with L-ascorbate differentially induced cell death, dependent on the SVCT-2 protein level. Moreover, knockdown of endogenous SVCT-2 via RNA interference in breast cancer cells expressing high levels of the protein induced resistance to L-ascorbate treatment, whereas transfection with SVCT-2 expression plasmids led to enhanced L-ascorbate chemosensitivity. Surprisingly, tumor regression by L-ascorbate administration in mice bearing tumor cell xenograft also corresponded to the SVCT-2 protein level. Interestingly, SVCT-2 expression was absent or weak in normal tissues, but strongly detected in tumor samples obtained from breast cancer patients. In addition, enhanced chemosensitivity to L-ascorbate occurred as a result of caspase-independent autophagy, which was mediated by beclin-1 and LC3 II. In addition, treatment with N-acetyl-L-cysteine, a reactive oxygen species (ROS) scavenger, suppressed the induction of beclin-1 and LC3 II, implying that the differential SVCT-2 protein-dependent L-ascorbate uptake was attributable to intracellular ROS induced by L-ascorbate, subsequently leading to autophagy. These results suggest that functional SVCT-2 sensitizes breast cancer cells to autophagic damage by increasing the L-ascorbate concentration and intracellular ROS production and furthermore, SVCT-2 in breast cancer may act as an indicator for commencing L-ascorbate treatment.Oncogene advance online publication, 4 June 2012; doi:10.1038/onc.2012.176.
    No preview · Article · Jun 2012 · Oncogene
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    J-C Jo · J-L Lee · M-H Ryu · H M Chang · M Kim · H J Lee · H-S Kim · J-G Shin · T-W Kim · Y-K Kang
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    ABSTRACT: To assess the efficacy and safety of individualised dose optimisation of irinotecan monotherapy as salvage treatment for advanced gastric cancer (AGC). A total of 43 patients were enrolled. Intravenous irinotecan (350 mg m(-2)) was administered every 3 weeks. The dose was increased (425 mg m(-2) and 500 mg m(-2)) or decreased (250 mg m(-2)) depending on patient tolerance. UGT1A1 genotypes were determined by direct sequencing of genomic DNA extracted from peripheral blood. A total of 183 cycles of irinotecan were administered, with a median of four cycles per patient. The overall response rate was 9.3%, and the disease control rate was 62.8%. Median time to disease progression was 2.8 months, and median overall survival was 8.0 months. Grade 3-4 neutropenia was the most common toxicity (53.5%), and febrile neutropenia was the least common toxicity (4.6%). Compared with defective allele groups, UGT1A1 *1/*1 was associated with a lower incidence of grade 3-4 neutropenia during the first cycle (P=0.018). Individualised irinotecan dose escalation based on patient tolerance was not associated with increased toxicity and shows modest activity as salvage chemotherapy for AGC. The role of UGT1A1 genotype in clinical toxicity requires further evaluation.
    Full-text · Article · Apr 2012 · British Journal of Cancer
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    ABSTRACT: This randomised multicentre phase II study was conducted to investigate the activity and safety of two oral fluoropyrimidines, capecitabine or S-1, in elderly patients with advanced gastric cancer (AGC). Elderly (>or=65 years) chemo-naive patients with AGC were randomly assigned to receive capecitabine 1250 mg m(-2) two times daily on days 1-14 every 3 weeks or S-1 40-60 mg two times daily according to body surface area on days 1-28 every 6 weeks. Ninety-six patients were enrolled and 91 patients were randomised to capecitabine (N=46) or S-1 (N=45). Overall response rate, the primary end point, was 27.2% (95% CI, 14.1-40.4, 12 of 44 assessable patients) with capecitabine and 28.9% (95% CI, 15.6-42.1, 13 of 45) with S-1. Median times to progression and overall survival in the capecitabine arm (4.7 and 9.5 months, respectively) were similar to those in the S-1 arm (4.2 and 8.2 months, respectively). The incidence of grade 3-4 granulocytopenia was 6.8% with capecitabine and 4.8% with S-1. Grade 3-4 nonhaematologic toxicities were: asthenia (9.1% with capecitabine vs 7.1% with S-1), anorexia (6.8 vs 9.5%), diarrhoea (2.3 vs 0%), and hand-foot syndrome (6.8 vs 0%). Both capecitabine and S-1 monotherapies were active and tolerable as first-line treatment for elderly patients with AGC.
    Full-text · Article · Sep 2008 · British Journal of Cancer