• Polymer(Korea)
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• v.26 no.5
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• pp.691-700
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• 2002

Interstitial therapy using biodegradable polymeric device loaded with anticancer agent can deliver the drug to the tumor site at high concentration, resulting in an increase of therapeutic efficacy. 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU, carmustine) is most commonly used as chemotherapeutic agent for brain tumors. The design of implantable device is regarded as an important factor lot the efficient delivery of antitumor agent to targeting site. In order to control the release profile of drug, the release pattern of BCNU with the changes of various dimension and additives was investigated. The PLGA wafers containing 3.85, 10, 20 and 30% of BCNU were prepared in various shape (diameter of 3, 5 and 10 mm, thickness of 0.5, 1 and 2 mm) by direct compression method. In vitro drug release profile of BCNU-loaded PLGA wafers could be controlled by changing the dimension of wafers such as initial drug content, weight, diameter, thickness, volume and surface area of wafers, as well as PLGA molecular weight and additives. Drug release from BCNU-loaded PLGA wafers was facilitated with an increase of BCNU-loading amount or presence of poly(N-vinylpyrrolidone)(PVP) or sodium chloride (NaCl). The effects of various geometric factors and additives on the BCNU release pattern were confirmed by the investigation of mass loss and morphology of BCNU-loaded PLGA wafers.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.122-122
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• 1995

본 연구는 유전공학적인 방법으로 합성된 상피세포성장호르몬인 DWP-401에 대한 마우스의 반복투여에 의한 아급성독성을 조사하기 위하여 실시하였다. 시험군은 ICR 마우스 압수 각각 10 마리씩으로 하여 3 개의 처치군 및 대조군(0, 1, 0.2, 0.04 mg/kg)과 회복시험군(0, 1 mg/kg)을 두었다. 시험물질은 13 주간 경배 부 피하에 1 주에 6 회의 빈도로 투여하였고 대조군과 최고용량 군에서 5 주간의 회복기간을 두었다. 시험기간 중 체중, 사료섭취량 및 음수섭취량을 측정하였고, 뇨검사, 안검사, 혈액학적검사, 혈액생화학적 검사, 부검소견관찰, 장기중량측정 및 병리조직학적검사를 실시하였다. 이상의 실험결과 DWP-401의 마우스에 대한 표적장기는 상피세포, 간장, 비장, 부신, 방광 신장, 각 장기의 복막과 흉막, 림프계, 난소 및 투여부위였고 회복성이 인정되었다. 무해용량은 0.04 mg/kg/day였으며 확실 중독량은 0.2 mg/kg/day 이상으로 사료되었다.

• Journal of Life Science
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• v.20 no.1
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• pp.103-112
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• 2010

Pemetrexed has demonstrated clinical activity in non-small cell lung cancer (NSCLC) as well as other solid tumors. It transports into the cells via reduced folate carrier (RFC) and is polyglutamated by folypolyglutamate synthetase (FPGS). Pemetrexed directly inhibits several folate-dependent enzymes such as thymidylate synthase (TS), dihydrofolate reductase (DHFR), and glycinamide ribonucleotide formyltransferase (GARFT). We investigated the effects of genetic variations and the expression of RFC, FPGS, TS and DHFR enzymes on drug sensitivity to pemetrexed in NSCLC cells. Polymorphisms in RFC, FPGS, and DHFR were genotyped in four NSCLC cells - A549, PC14, HCC-1588, and H226. Real-time RT-PCR and Western blot was performed to evaluate mRNA transcripts and protein of these genes. The cytotoxicity of pemetrexed was measured by SRB assay. In PC14 and H226 cells, increased mRNA expressions of RFC and FPGS were associated with higher cytotoxicity to pemetrexed. 2R/2R genotype of TS and its increased mRNA expression were associated with drug resistance to pemetrexed in A549 cells, whereas 3R/3R genotype in TS with decreased mRNA expression was associated with higher sensitivity in H226 cells. After pemetrexed treatment, an inverse change of DHFR mRNA and protein expression was found. The strongest linkage disequilibrium (LD) was discovered between-1726C>T and -1188A>C SNP of DHFR gene. Our findings suggest the cytotoxic effect of pemetrexed may be associated with genetic polymorphisms and the expression level of genes involved in pemetrexed metabolisms in NSCLC cells.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.1
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• pp.11-18
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• 2022

De novo drug design is the process of developing new drugs that can interact with biological targets such as protein receptors. Traditional process of de novo drug design consists of drug candidate discovery and drug development, but it requires a long time of more than 10 years to develop a new drug. Deep learning-based methods are being studied to shorten this period and efficiently find chemical compounds for new drug candidates. Many existing deep learning-based drug design models utilize recurrent neural networks to generate a chemical entity represented by SMILES strings, but due to the disadvantages of the recurrent networks, such as slow training speed and poor understanding of complex molecular formula rules, there is room for improvement. To overcome these shortcomings, we propose a deep learning model for SMILES string generation using variational autoencoders with self-attention mechanism. Our proposed model decreased the training time by 1/26 compared to the latest drug design model, as well as generated valid SMILES more effectively.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.664-666
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• 2005

막횡단 단백질(Transmembrane Protein)은 약물표적(drug target)으로 신약개발로 대표되는 바이오 산업에서 중요한 연구대상이 되고 있다. 막횡단 단백질의 구조는 실험적 기법 또는 컴퓨터 모델링 기술을 이용하여 연구되고 있으며 컴퓨터 모델링 방법 중에서는 Hidden Markov Mode(HMM)에 기반한 시스템들이 좋은 성능을 보이고 있다. 그런데 이러한 시스템들은 구조형성에 관여하는 단백질의 다양한 특성에 대한 지식은 많이 고려하고 있지 않다. 만약 이러한 특성들이 고려된다면 구조 예측에 효과적인 보다 지능적인 모델을 만드는데 도움을 줄 수 있을 것이다. 본 논문은 단백질의 특성과 관련한 다양한 정보들을 융합하는데 효율적인 최대엔트로피모델(Maximum Entropy Model)을 이용하여 막횡단 단백질의 서열(sequence)로부터 막횡단 지역을 예측하는 방법을 제시하고자 한다.

• Polymer(Korea)
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• v.30 no.6
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• pp.512-518
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• 2006

A biodegradable polymer poly((R) -3-hydroxybutyric acid) (PHB) was conjugated with a hydrophilic polymer poly(ethylene glycol) (PEG) by the ttansesterification reaction to form the amphiphilic block copolymer. PHB with low molecular weight ($3000{\sim}30000$) was appropriated for the drug delivery materials. High molecular weight PHB was hydrolyzed by an acid-catalyst to produce the low molecular weight one. Amphiphilic block copolymer was formed the self-assembled polymeric micelle system in the aqueous solution that the hydrophillic PEG was wraped the hydrophobic PHB. Generally, polymeric micelle forms the small particle between $10{\sim}200nm$. These polymeric micelle systems have been widely used for the drug delivery systems because they were biodegradable, biocompatible, non-toxic and patient compliant. The hydroxyl group of PEG was substituted with carboxyl group which has the reactivity to the ester group of PHB. Amphiphilic block copolymer was conjugated between PHB, and modified PEG at $176^{\circ}C$ which was higher than the melting point of PHB. Transesterification reaction was verified with DSC, FTIR, $^1H-NMR$. In the aqueous solution, critical micelle concentration (CMC) of the mPEG-co-PHB copolymer measured by the fluororescence scanning spectrometer was $5{\times}10^{-5}g/L$. The shape and size of the nanoparticle was taken by dynamic light scattering and atomic force microscopy. The size of the nanoparticle was about 130 nm and the shape was spherical. Our polymeric micelle system can be used as the passive targeting drug delivery system.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.2
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• pp.107-121
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• 2021

Skin hypopigmentation, which is observed in albinism or vitiligo, occurs when melanin synthesis is decreased by genetic, epigenetic, and other factors. To identify drug candidates that can promote melanin synthesis in cells, we screened an epigenetic modulator library consisting of 141 cell-permeable, small molecule drugs. B16/F10 murine melanoma cells were treated with each drug at 0.1 𝜇M and melanin synthesis and cell viability were subsequently monitored. As a result, (-)-neplanocin A, 3-deazaneplanocin A (DZNep), and DZNep hydrochloride were found to increase cellular melanin synthesis without causing cytotoxicity. Because these three structurally related drugs exhibited similar dose-dependent effects on melanin synthesis and cell viability, DZNep was selected as a representative drug for additional experiments. DZNep increased intracellular melanin content and tyrosinase (TYR) activity. DZNep also induced the expression of TYR, tyrosinase-related protein 1 (TYRP1), and dopachrome tautomerase (DCT) at the mRNA and protein levels. DZNep also induced the mRNA and protein expression of microphthalmia-associated transcription factor (MITF), a key regulator of melanin synthesis. DZNep is a specific inhibitor of S-adenosylhomocysteine hydrolase and it caused the accumulation of S-adenosylhomocysteine that inhibits histone methyltransferases in cells. This study suggests that melanogenesis can be modulated by targeting S-adenosylhomocysteine hydrolase in certain cellular contexts.

• Journal of Pharmaceutical Investigation
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• v.19 no.4
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• pp.195-202
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• 1989

In attempt to improve the chemotherapeutic activity of adriamycin, adriamycin-entrapped HSA microspheres were prepared and investigated by the various in vitro experiments. The shape, surface characteristics and size distribution of HSA microspheres are observed by scanning electron microscopy. The in vitro drug release, albumin matrix degradation by protease of HSA microspheres were studied. The shape of HSA microspheres were spherical and the surface was smooth and compact. The size of HSA microspheres ranged from 0.4 to $2.5\;{\mu}m$ and have average diameters of 0.5 to $0.7\;{\mu}m$. The size distribution of HSA microspheres prepared by ultrasonication was mainly affected by albumin concentration and heating time in the process of hardening. In in vitro, almost all adriamycin was released from HSA microspheres for 8 hr. Analysis of the resulting adriamycin release profiles demonstrated that adriamycin is released from the microspheres in two distinct steps, a fast phase (until 30 min) followed by a much slower sustained release phase. Drug release, which is due to diffusion, was depended on the rate of matrix hydration. Drug release was largely affected by albumin concentration and heating temperature during the process of hardening. Albumin matrix degradation of HSA microspheres was affected by heating temperature and albumin concentration. Higher temperature and longer times generally produce harder, less porous, and slowly degradable microspheres.

• Journal of Biomedical Engineering Research
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• v.38 no.1
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• pp.43-48
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• 2017

Chemotherapy, radiation therapy, and surgery are major methods to treat cancer. However, current cancer treatments report severe side effects and high recurrences. Recent studies about engineering nanoparticles as a drug carrier suggest possibilities in terms of specific targeting and spatiotemporal release of drugs. While many nanoparticles demonstrate lower toxicity and better targeting results than free drugs, they still need to improve their performance dramatically in terms of targeting accuracy, immune responses, and non-specific accumulation at organs. One possible way to overcome the challenges is to make precisely controlled nanoparticles with respect to size, shape, surface properties, and mechanical stiffness. Here, we demonstrate $500{\times}200nm$ discoidal polymeric nanoconstructs (DPNs) as a drug delivery carrier. DPNs were prepared by using a top-down fabrication method that we previously reported to control shape as well as size. Moreover, DPNs have multiple payloads, poly lactic-co-glycolic acid (PLGA), polyethylene glycol (PEG), lipid-Rhodamine B dye (RhB) and Salinomycin. In this study, we demonstrated a potential of DPNs as a drug carrier to treat cancer.

• Journal of the Korea Convergence Society
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• v.10 no.1
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• pp.285-290
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• 2019

AHR regulates the expression of xenobiotics metabolizing enzymes (XMEs) as a transcription fact upon binding of ligands that are mainly aryl hydrocarbons. The role of AHR in human physiology has been intensively investigated for the past decades, however our understanding on AHR yet to be elucidated largely due to the lack of proper chemical agents. It has been demonstrated that AHR correlates to pathogenesis for some diseases in recent studies suggesting that the study on the AHR may provide a valid therapeutic target. Classical antagonists in current use are reported to be partially agonistic whereas a pure antagonist is yet to be found. In this study, phenyldiazenylaniline has been designed based on the structure of two known AHR antagonist, Resveratrol and CH223191. The derivatives of phenyldiazenylaniline have been prepared and subjected to assessment as an AHR antagonist in order to optimize the AHR antagonistic activity of the designed structure by means of convergence study of organic synthesis and molecular biology.