• Proceedings of the Korean Society of Toxicology Conference
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• 2004.05a
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• pp.27-29
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• 2004

Drug transporters play an essential role in the absorption, distribution and elimination of clinical drugs, nutrients and toxicants. The importance of the transporters is exampled by therapeutic failure in cancer chemotherapy that is mainly caused by the overexpression of multidrug resistance (MDR)-related transporters. In addition, the transporters may involve in drug-drug interactions that lead to serious adverse drug responses and some transporters also contribute to inter-individual variation in drug responses. As an effort to understand the mechanism underlying the inter-individual variation of transporters activity, genetic and environmental factors influencing the expression or function of the transporters have extensively explored through last decade. Among them, genetic polymorphism of drug transporter encoding genes has generated much interest since the discovery of functional single nucleotide polymorphisms (SNP) of MDRl gene. Besides drug transporters, xenobiotic receptors also modulate drug disposition by regulating the transcription of drug metabolizing enzymes and drug transporters. Among many xenobiotic receptors, pregnane X receptor (PXR) and constitutive androstane receptor (CAR) are two most well characterized since these receptors show wide substrate specificities and regulate the expression of various enzymes involved in drug disposition. Recently, several functional genetic polymorphisms were reported in PXR coding gene. In the present study, genetic polymorph isms of two drug transporters, MDR1 and BCRP, and two xenobiotic receptors, PXR and CAR, were investigated in Korean population.

• Parasites, Hosts and Diseases
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• v.46 no.3
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• pp.119-125
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• 2008

Lymphatic filariasis, transmitted by mosquitoes is the commonest cause of lymphedema in endemic countries. Among 120 million infected people in 83 countries, up to 16 million have lymphedema. Microfilariae ingested by mosquitoes grow into infective larvae. These larvae entering humans after infected mosquito bites grow in the lymphatics to adult worms that cause damage to lymphatics resulting in dilatation of lymph vessels. This earliest pathology is demonstrated in adults as well as in children, by ultrasonography, lymphoscintigraphy and histopathology studies. Once established, this damage was thought to be irreversible. This lymphatic damage predisposes to bacterial infection that causes recurrent acute attacks of dermato-lymphangio-adenitis in the affected limbs. Bacteria, mainly streptococci gain entry into the lymphatics through 'entry lesions' in skin, like interdigital fungal infections, injuries, eczema or similar causes that disrupt integrity of skin. Attacks of dermato-lymphangio-adenitis aggravates lymphatic damage causing lymphedema, which gets worse with repeated acute attacks. Elephantiasis is a late manifestation of lymphatic filariasis, which apart from limbs may involve genitalia or breasts. Lymphedema management includes use of antifilarial drugs in early stages, treatment and prevention of acute attacks through 'limb-hygiene', antibiotics and antifungals where indicated, and physical measures to reduce the swelling. In selected cases surgery is helpful.

• Radiation Oncology Journal
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• v.18 no.4
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• pp.329-336
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• 2000

Backgrounds : The purpose of this study was to identify drugs that can enhance radioresponse of murine fepatocarcinorna. Methods : CSH/HeJ mice bearing 8 mm tumors of murine fepatocarcinorna, HCa-1, were treated with 25 Gy radiation and one of the following drugs: 5-Fu, 150 mghg; adriamycin, 8 mg/kg; cisplatin, 6 mg/kg; paclitaxel, 40 mg/kg; and gemcitabine, 50 mg/kg. Tumor response to the treatment was determined by tumor growth delay assay and by enhancement factor. Apoptotic level was assessed in tissue sections. Expression of regulating molecules was analyzed by western blotting for p53, Bcl-2, Bax, Bcl-XL, Bcl-XS, and p21$^{WAF1/CIP1}$. Results :Among the drugs tested, only gemcitabine enhanced the antitumor effect of radiation, with enhancement factor of 1.6. Induction of apoptosis by a combination of gemcitabine and radiation was shown as only additive level. In analysis of radiation-induced expression of regulating molecules, the most significant change by combining gemcitabine was activation of p21$^{WAF1/CIP1}$ Conclusion :Gemcitabine is the first drug showing an enhancement of radioresponse in murine hepatocarcinoma, when combined with radiation. The key element of enhancement is thought to be p21$^{WAF1/CIP1}$.

• Tuberculosis and Respiratory Diseases
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• v.71 no.1
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• pp.15-23
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• 2011

Background: Gefitinib and erlotinib are useful, molecular targeted agents in patients with non-small-cell lung cancer (NSCLC) who failed previous chemotherapy. We compared the efficacy and toxicity of two drugs in patients with squamous cell lung cancer, most of whom are male smokers. Methods: We retrospectively reviewed the clinical information on patients with NSCLC who were treated with gefitinib or erlotinib treatment at Chonnam National University Hwasun Hospital between July 2002 and November 2009. The overall response rate (ORR), overall survival (OS) and progression-free survival (PFS) were compared between the two drugs. Results: A total of 182 (100 gefitinib vs. 82 erlotinib) of 584 patients treated by targeted agents had squamous histology. Of the 182 patients, 167 (91.7%) were male and 159 (87.4%) were smokers. The ORR and disease control rate (DCR) were 4.9% and 40.6%, and there was no significant difference between gefitinib and erlotinib (ORR, 5.0% vs 4.8%; p=0.970; DCR, 40.0% vs 41.4%; p=0.439). The median OS in the gefitinib group was 12.1 months, and that in the erlotinib was 12.7 months (hazard ratio [HR], 1.282; 95% confidence interval [CI], 0.771~2.134; p=0.339). The median PFS for the gefitinib group was 1.40 months, compared with 1.37 months for the erlotinib group (HR, 1.092; 95% CI, 0.809~1.474; p=0.564). Skin rash ${\geq}$grade 3 was more common in erlotinib (12.2%) than gefitinib (1.0%, p=0.003) groups. Conclusion: This retrospective study showed that the two drugs appear to have similar antitumor efficacy and toxicity except for skin rash.

• Tuberculosis and Respiratory Diseases
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• v.44 no.5
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• pp.975-991
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• 1997

Background : Many patients with isoniazid and rifampin-resistant pulmonary tuberculosis have organisms that are also resistant to other first-line drugs. Despite of aggressive retreatment chemotherapy, the results are often unsuccessful, with a failure rate approaching 40%. Recently, there has been a revival of resectional surgery for the treatment of multidrug-resistant pulmonary tuberculosis. Methods : A retrospective analyses of the case records and radiographic findings were done. Between January 1991 and December 1995, 14 human immunodeficiency virus (HIV)-seronegative patients with multidrug-resistant pulmonary tuberculosis were selected for resection to supplement chemotherapy. All patients had organisms resistant to many of the first-line drugs, including both isoniazid and rifampin. Results : Despite of aggressive therapy for median duration of 9.5 months, 12 of the 14 patients (86%) were still sputum smear and/or culture positive at the time of surgery. The disease was generally extensive. Although main lesions of the disease including thick-walled cavities were localized in one lung, lesser amounts of contralateral disease were demonstrated in 10 of 14 (71%). Types of surgery performed were pneumonectomy including extrapleural pneumonectomy in six patients, lobectomy or lobectomy plus in six patients, and segmentectomy in two patients. The resected lung appeared to have poor function ; preoperative perfusion lung scan showed only 4.8% of the total perfusion to the resected portion of the lung. There were no operative deaths. Two patients had major postoperative complications including empyema with bronchopleural fistula and prolonged air leak, respectively. Of the 14 patients, 13 (93%) remained sputum-culture-negative for M. tuberculosis for a median duration of 23 months and one remained continuously sputum smear and culture positive for M. tuberculosis. Conclusion : On the basis of comparison with historical controls, adjunctive resectional surgery appears to play a significant beneficial role in the management of patients with multidrug-resistant pulmonary tuberculosis if the disease is localized and there are adequate reserve in pulmonary function.

• Tuberculosis and Respiratory Diseases
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• v.58 no.4
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• pp.344-351
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• 2005

Background : Both gemcitabine and vinorelbine are effective anticancer drugs with mild toxicity on non-small cell lung cancer, and monotherapy of these drugs are effective as a second-line chemotherapy. The aim of this trial was to assess the response and toxicity of a combination of gemcitabine and vinorelbine in patients of previously treated for non-small cell lung cancer. Materials and Methods : 24 patients, initial stage III A/B,IV and previously treated with platinium and taxane based regimens, were enrolled from June 2000 to March 2004. The regimens consisted of vinorelbine $25mg/m^2$ followed by an infusion of gemcitabine $1000mg/m^2$ on day 1 and day 8 every three weeks. This course was repeated more than twice. Results : Twenty-four patients were analyzed for the response, survival rate, and toxicities. The overall response was 17% with a complete remission rate of 4%. The median time-to progression (TTP) was 3.1 months (95%, CI 1-10months), and the survival time was 8.2 months (95%, CI 1-23 months). The grade 3/4 toxicities encountered were neutropenia (12.5%), anemia (0%), thrombocytopenia (0%). Non-hematological 3/4 toxicities were not observed. Conclusion : A combination of gemcitabine and vinorelbine in patients previously treated for non-small cell lung cancer provides a relatively good response rate, and a low toxicity profile. However, further study will be needed to confirm its effectiveness.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7863-7867
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• 2014

Background: Retinoblastoma is a rare type of cancer that usually develops in early childhood. If left untreated it can cause blindness and even death. The aim of this study is to determine sociodemographic and clinical features of retinoblastoma patients and also to determine the treatment pattern and outcome in Malaysia. Materials and Methods: Data for this study were retrieved from the Retinoblastoma Registry of the National Eye Database (NED) in Malaysia. Hospital Kuala Lumpur, Hospital Umum Kuching, Sarawak and Hospital Queen Elizabeth, Kota Kinabalu were the major source data providers for this study. Data collected in the registry cover demography, clinical presentation, modes of treatment, outcomes and complications. Results: The study group consisted of 119 patients (162 eyes) diagnosed with retinoblastoma between 2004 and 2012. There were 68 male (57.1%) and 51 (42.9%) female. The median age at presentation was 22 months. A majority of patients were Malays (54.6%), followed by Chinese (18, 5%), Indians (8.4%), and indigenous races (15.9%). Seventy six (63.8%) patients had unilateral involvement whereas 43 patients had bilateral disease (36.1%). It was found that most children presented with leukocoria (110 patients), followed by strabismus (19), and protopsis (12). Among the 76 with unilateral involvement (76 eyes), enucleation was performed for a majority (79%). More than half of these patients had extraocular extension. Of the 40 who received chemotherapy, 95% were given drugs systemically. Furthermore, in 43 patients with bilateral involvement (86 eyes), 35 (41%) eyes were enucleated and 17 (49%) showed extraocular extension. Seventy-two percent of these patients received systemic chemotherapy. The patients were followed up 1 year after diagnosis, whereby 66 were found to be alive and 4 dead. Sixteen patients defaulted treatment and were lost to follow-up, whereas follow-up data were not available in 33 patients. Conclusions: Patients with retinoblastoma in this middle-income Asian setting are presenting at late stages. As a result, a high proportion of patients warrant aggressive management such as enucleation. We also showed that a high number of patients default follow-up. Therefore, reduction in refusal or delay to initial treatment, and follow-up should be emphasized in order to improve the survival rates of retinoblastoma in this part of the world.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.6135-6140
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• 2013

Background: Breast cancer is a common malignant tumor which affects health of women and multidrug resistance (MDR) is one of the main factors leading to failure of chemotherapy. This study was conducted to establish paclitaxel-resistant breast cancer cell line and nude mice models to explore underlying mechanisms of MDR. Methods: The breast cancer drug-sensitive cell line MCF-7 (MCF-7/S) was exposed in stepwise escalating paclitaxel (TAX) to induce a resistant cell line MCF-7/TAX. Cell sensitivity to drugs and growth curves were measured by MTT assay. Changes of cell morphology and ultrastructure were examined by optical and electron microscopy. The cell cycle distribution was determined by flow cytometry. Furthermore, expression of proteins related to breast cancer occurrence and MDR was tested by immunocytochemistry. In Vivo, nude mice were injected with MCF-7/S and MCF-7/TAX cells and weights and tumor sizes were observed after paclitaxel treatment. In addition, proteins involved breast cancer and MDR were detected by immunohistochemistry. Results: Compared to MCF-7/S, MCF-7/TAX cells had a higher resistance to paclitaxel, cross-resistance and prolonged doubling time. Moreover, MCF-7/TAX showed obvious alterations of ultrastructure. Estrogen receptor (ER) expression was low in drug resistant cells and tumors while expression of human epidermal growth factor receptor 2 (HER2) and Ki-67 was up-regulated. P-glycoprotein (P-gp), lung resistance-related protein (LRP) and glutathione-S-transferase-${\pi}$ (GST-${\pi}$) involved in the MDR phenotype of resistant cells and tumors were all overexpressed. Conclusion: The underlying MDR mechanism of breast cancer may involve increased expression of P-gp, LRP and GST-${\pi}$.

• Journal of Life Science
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• v.28 no.12
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• pp.1469-1476
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• 2018

Occurrence of the Warburg effect in solid tumors causes resistance to cancer chemotherapy, and targeting energy metabolisms such as aerobic glycolysis is a potential strategy for alternative treatment. Dichloroacetate (DCA), an inhibitor of pyruvate dehydrogenase kinase (PDK), shifts glucose metabolism from aerobic glycolysis to oxidative phosphorylation (OxPhos) in many cancers. In this study, we investigated the anticancer effect of DCA on a human anaplastic thyroid cancer (ATC) cell line, 8505C. We found that DCA selectively inhibits cell proliferation of the 8505C line but not of a normal thyroid line. In 8505C, the cell cycle was arrested at the G1/S phase with DCA treatment as a result of decreased antiapoptotic proteins such as $HIF1{\alpha}$, PDK1, and Bcl-2 and increased proapoptotic proteins such as Bax and p21. DCA treatment enhanced the production of reactive oxygen species which consequently induced cell cycle arrest and apoptosis. Interestingly, DCA treatment not only reduced lactate production but also increased the expression of sodium-iodine symporter, indicating that it restores the OxPhos of glucose metabolism and the iodine metabolism of the ATC. Taken together, our findings suggest that PDK inhibitors such as DCA could be useful anticancer drugs for the treatment of ATC and may also be helpful in combination with chemotherapy and radiotherapy.

• Journal of Life Science
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• v.33 no.6
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• pp.512-522
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• 2023

Cancer with unlimited cell growth is a leading cause of death globally. Various cancer treatments, including surgery, chemotherapy, radiation therapy, immunotherapy, and targeted therapy, can be applied alone or in combination depending on the cancer type and stage. New treatments with fewer side effects than previous cancer treatments are continually under development and in demand. Undifferentiated stem cells with unlimited cell growth are gradually changed via cellular differentiation to arrest cell growth. In this study, we reviewed the possibility of treating cancer by using cellular differentiation into the adipocytes in cancer cells. In previous in vitro studies, oral antidiabetic drugs of the thiazolidinedione (TDZ) class, such as rosiglitazone and pioglitazone, were induced into the adipocytes in various cancer cell lines via increased peroxisome proliferator-activated receptor-γ (PPAR γ) expression and glucose uptake, which is the key regulator of adipogenesis and the energy metabolism pathway. The differentiated adipogenic cancer cells treated with TDZ inhibited cell growth and had a less cellulotoxic effect. This adipogenic differentiation treatment suggests a possible chemotherapy option in cancer cells with high and abnormal glucose metabolism levels. However, the effects of the in vivo adipogenic differentiation treatment need to be thoroughly investigated in different types of stem and normal cells with other side effects.