• Biomolecules & Therapeutics
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• 제32권1호
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• pp.154-161
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• 2024

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disorder that causes progressive paralysis. L-Citrulline is a nonessential neutral amino acid produced by L-arginine via nitric oxide synthase (NOS). According to previous studies, the pathogenesis of ALS entails glutamate toxicity, oxidative stress, protein misfolding, and neurofilament disruption. In addition, L-citrulline prevents neuronal cell death in brain ischemia; therefore, we investigated the change in the transport of L-citrulline under various pathological conditions in a cell line model of ALS. We examined the uptake of [¹⁴C]L-citrulline in wild-type (hSOD1wt/WT) and mutant NSC-34/ SOD1^G93A (MT) cell lines. The cell viability was determined via MTT assay. A transport study was performed to determine the uptake of [¹⁴C]L-citrulline. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis was performed to determine the expression levels of rat large neutral amino acid transported 1 (rLAT1) in ALS cell lines. Nitric oxide (NO) assay was performed using Griess reagent. L-Citrulline had a restorative effect on glutamate induced cell death, and increased [¹⁴C]L-citrulline uptake and mRNA levels of the large neutral amino acid transporter (LAT1) in the glutamate-treated ALS disease model (MT). NO levels increased significantly when MT cells were pretreated with glutamate for 24 h and restored by co-treatment with L-citrulline. Co-treatment of MT cells with L-arginine, an NO donor, increased NO levels. NSC-34 cells exposed to high glucose conditions showed a significant increase in [¹⁴C]L-citrulline uptake and LAT1 mRNA expression levels, which were restored to normal levels upon co-treatment with unlabeled L-citrulline. In contrast, exposure of the MT cell line to tumor necrosis factor alpha, lipopolysaccharides, and hypertonic condition decreased the uptake significantly which was restored to the normal level by co-treating with unlabeled L-citrulline. L-Citrulline can restore NO levels and cellular uptake in ALS-affected cells with glutamate cytotoxicity, pro-inflammatory cytokines, or other pathological states, suggesting that L-citrulline supplementation in ALS may play a key role in providing neuroprotection.

• Journal of Gastric Cancer
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• 제5권3호
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• pp.191-199
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• 2005

목적: Helicobacter pylori(H. pylori) 감염이 숙주의 혈관형성을 유도하는 작용은 잘 알려져 있으나, 이러한 혈관형성 유도작용을 억제하는 기전이나 치료법은 아직 연구되지 않았다. 이에 저자들은 HP 감염이 위 점막의 혈관형성에 미치는 영향과 이에 대한 gastric proton pump inhibitor (PPI)의 강력한 억제 효과를 규명하기 위해 본 연구를 시행하였다. 대상 및 방법: H. pylori 양성인 20명의 위염 환자들과 음성인 18명의 위염 환자들을 대상으로 내시경생검으로 수집한 위 점막의 CD34의 발현을 조사하였다. Hypoxia-inducible factor-1 alpha $(HIF-1{\alpha})$와 vascular endothelial growth factor(VEGF)의 발현은 RT-PCR로 측정하였다. H. pylori 감염이 human umbilical vein endothelial cell의 분화에 미치는 영향을 평가하기 위하여 in vitro 혈관형성 실험을 시행하였다. 결과: 면역조직화학 염색 검사상 H. pylori음성 위염에서 보다 H. pylori양성 위염에서 위 점막층의 CD34양성 혈과이 유의하게 많이 발현되었으며, 이러한 결과는 $HIF-1{\alpha}$의 발현과 밀접한 상관관계를 보였다. H. pylori에 감염된 위 점막 세포의 조건화된 배지는 human umbilical vein endothelial cell의 세관 형성을 자극하였다. 그리고 H. pylori 박멸치료에 사용되는 PPI가 HP 유도성 혈관형성을 현저히 억제하는 효과를 발견하였고, PPI의 작용은 H. pylori 유도성 혈관형성의 주된 신호전달 경로인 MAP kinase ERK1/2의 인산화를 억제함으로 이루어졌다. 결론: PPI가 H. pylori 유도성 혈관형성을 억제하다: 결과는 H, pylori가 관련된 암 발생의 예방을 위하여 PPI를 사용한 항혈관형성 치료가 사용될 수 있음을 제시한다.

• Journal of Ginseng Research
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• 제46권6호
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• pp.738-749
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• 2022

Background: Ginseng possesses antitumor effects, and ginsenosides are considered to be one of its main active chemical components. Ginsenosides can further be hydrolyzed to generate secondary saponins, and 20(R)-panaxotriol is an important sapogenin of ginsenosides. We aimed to synthesize a new ginsengenin derivative from 20(R)-panaxotriol and investigate its antitumor activity in vivo and in vitro. Methods: Here, 20(R)-panaxotriol was selected as a precursor and was modified into its derivatives. The new products were characterized by ¹H-NMR, ¹³C-NMR and HR-MS and evaluated by molecular docking, MTT, luciferase reporter assay, western blotting, immunofluorescent staining, colony formation assay, EdU labeling and immunofluorescence, apoptosis assay, cells migration assay, transwell assay and in vivo antitumor activity assay. Results: The derivative with the best antitumor activity was identified as 6,12-dihydroxy-4,4,8,10,14-pentamethyl-17-(2,6,6-trimethyltetrahydro-2H-pyran-2-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl(tert-butoxycarbonyl)glycinate (A11). The focus of this research was on the antitumor activity of the derivatives. The efficacy of the derivative A11 (IC₅₀ < 0.3 µM) was more than 100 times higher than that of 20(R)- panaxotriol (IC₅₀ > 30 µM). In addition, A11 inhibited the protein expression and nuclear accumulation of the hypoxia-inducible factor HIF-1α in HeLa cells under hypoxic conditions in a dose-dependent manner. Moreover, A11 dose-dependently inhibited the proliferation, migration, and invasion of HeLa cells, while promoting their apoptosis. Notably, the inhibition by A11 was more significant than that by 20(R)-panaxotriol (p < 0.01) in vivo. Conclusion: To our knowledge, this is the first study to report the production of derivative A11 from 20(R)-panaxotriol and its superior antitumor activity compared to its precursor. Moreover, derivative A11 can be used to further study and develop novel antitumor drugs.