• Biomolecules & Therapeutics
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• 제30권4호
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• pp.360-367
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• 2022

Tropomyosin receptor kinase A (TrkA) protein is a receptor tyrosine kinase encoded by the NTRK1 gene. TrkA signaling mediates the proliferation, differentiation, and survival of neurons and other cells following stimulation by its ligand, the nerve growth factor. Chromosomal rearrangements of the NTRK1 gene result in the generation of TrkA fusion protein, which is known to cause deregulation of TrkA signaling. Targeting TrkA activity represents a promising strategy for the treatment of cancers that harbor the TrkA fusion protein. In this study, we evaluated the TrkA-inhibitory activity of the benzoxazole compound KRC-108. KRC-108 inhibited TrkA activity in an in vitro kinase assay, and suppressed the growth of KM12C colon cancer cells harboring an NTRK1 gene fusion. KRC-108 treatment induced cell cycle arrest, apoptotic cell death, and autophagy. KRC-108 suppressed the phosphorylation of downstream signaling molecules of TrkA, including Akt, phospholipase Cγ, and ERK1/2. Furthermore, KRC-108 exhibited antitumor activity in vivo in a KM12C cell xenograft model. These results indicate that KRC-108 may be a promising therapeutic agent for Trk fusion-positive cancers.

• The Korean Journal of Physiology and Pharmacology
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• 제27권4호
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• pp.383-398
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• 2023

Dihydroaustrasulfone alcohol (DA), the synthetic precursor of a natural compound (austrasulfone) isolated from the coral species Cladiella australis, has shown cytotoxic effects against cancer cells. However, it is unknown whether DA has antitumor effects on nasopharyngeal carcinoma (NPC). In this study, we determined the antitumor effects of DA and investigated its mechanism of action on human NPC cells. The MTT assay was used to determine the cytotoxic effect of DA. Subsequently, apoptosis and reactive oxygen species (ROS) analyses were performed by using flow cytometry. Apoptotic and PI3K/AKT pathway-related protein expression was determined using Western blotting. We found that DA significantly reduced the viability of NPC-39 cells and determined that apoptosis was involved in DA-induced cell death. The activity of caspase-9, caspase-8, caspase-3, and PARP induced by DA suggested caspase-mediated apoptosis in DA-treated NPC-39 cells. Apoptosis-associated proteins (DR4, DR5, FAS) in extrinsic pathways were also elevated by DA. The enhanced expression of proapoptotic Bax and decreased expression of antiapoptotic BCL-2 suggested that DA mediated mitochondrial apoptosis. DA reduced the expression of pPI3K and p-AKT in NPC-39 cells. DA also reduced apoptosis after introducing an active AKT cDNA, indicating that DA could block the PI3K/AKT pathway from being activated. DA increased intracellular ROS, but N-acetylcysteine (NAC), a ROS scavenger, reduced DA-induced cytotoxicity. NAC also reversed the chances in pPI3K/AKT expression and reduced DA-induced apoptosis. These findings suggest that ROS-mediates DA-induced apoptosis and PI3K/AKT signaling inactivation in human NPC cells.

• Tuberculosis and Respiratory Diseases
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• 제80권2호
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• pp.187-193
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• 2017

Background: Third-generation tyrosine kinase inhibitors of the epidermal growth factor receptor (EGFR-TKIs) have proved efficacious in treating non-small cell lung cancer (NSCLC) patients with acquired resistance resulting from the T790M mutation. However, since almost 50% patients with the acquired resistance do not harbor the T790M mutation, retreatment with first- or second-generation EGFR-TKIs may be a more viable therapeutic option. Here, we identified positive response predictors to retreatment, in patients who switched to a different EGFR-TKI, following initial treatment failure. Methods: This study retrospectively reviewed the medical records of 42 NSCLC patients with EGFR mutations, whose cancers had progressed following initial treatment with gefitinib or erlotinib, and who had switched to a different first-generation EGFR-TKI during subsequent retreatment. To identify high response rate predictors in the changed EGFR-TKI retreatment, we analyzed the relationship between clinical and demographic parameters, and positive clinical outcomes, following retreatment with EGFR-TKI. Results: Overall, 30 (71.4%) patients received gefitinib and 12 (28.6%) patients received erlotinib as their first EGFR-TKI treatment. Following retreatment with a different EGFR-TKI, the overall response and disease control rates were 21.4% and 64.3%, respectively. There was no significant association between their overall responses. The median progression-free survival (PFS) after retreatment was 2.0 months. However, PFS was significantly longer in patients whose time to progression was ${\geq}10months$ following initial EGFR-TKI treatment, who had a mutation of exon 19, or whose treatment interval was <90 days. Conclusion: In patients with acquired resistance to initial EGFR-TKI therapy, switched EGFR-TKI retreatment may be a salvage therapy for individuals possessing positive retreatment response predictors.

• Tuberculosis and Respiratory Diseases
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• 제50권6호
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• pp.668-675
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• 2001

연구배경 : 제21번 염색체가 3개(trisomy)인 다운 증후군(Down syndrome) 에서는 폐암을 포함한 고형종양의 빈도가 일반인에 비해 유의하게 낮다. 이와 같이 디운증후군에서 폐암 위험도가 낮은 것은 여분의 21번 염색체가 존재함에 따른 유전자-용량 효과(gene-dosage effect) 때문일 가능성이 있으며 이는 폐암의 발생과정에 관여하는 종양억제유전자가 21번 염색체에 있음을 의미한다. 저자들은 21번 염색체의 종양억제 유전자 발굴을 위한 선행연구로 21번 염색체 장암의 LOH 빈도와 LOH 유 무에 따른 임상상을 비교하였다. 방 법 : 근치적 절제술을 받은 비소세포폐암 39예를 대상으로 하였다. 동결된 폐암조직과 환자의 림프구에서 DNA를 추출한 후 21q의 5개의 현미부수체 표지자를 이용하여 PCR을 시행하고 6% polyacrylamide-8M urea gel에서 전기영동 한 후 silver 염색을 하였다. LOH는 암조직의 대립유전자 signal이 림프구의 50%이하로 감소된 경우로 판정하였으며 종양의 fractional allelic loss(FAL)는 informative 표지자 수에 대한 LOH가 발견된 표지자 수의 비로 계산하였다. 결 과 : 대상환자 39예 가운데 21예(53.8%)에서 한 개 이상의 표시자에서 LOH가 관찰되었다. LOH는 편평상피세포암의 경우 23예 가운데 15예(65.2%)에서, 선암의 경우는 16예 가운데 6예(37.5%)에서 관찰되어 편평상피세포암에서 LOH의 빈도가 높은 경향이 있었다. 편평상피세포암에서 LOH 빈도는 I 기 53.8%와 II-III기 80.0%로 진행된 병기에서 높은 경향이 있었으나 통계적 유의성은 없었다. 종양에서 대립 유전자 소실의 축적 정도를 반영하는 지표인 FAL치는 편평상피세포암의 경우 0.431(${\pm}0.375$)로 선암의 0.192(${\pm}0.276$)에 비해 통계적으로 유의하게 높았다. 편평상피세포암에서 FAL치는 I 기 0.391(${\pm}0.427$)인데 비해 II-III기는 0.484(${\pm}0.310$)로 통계적 유의성은 없었으나 진행된 병기에서 높은 경향을 보였다. 결 론 : 비소세포폐암에서 21q의 LOH가 흔히 관찰되었으며 이러한 결과는 비소세포폐암의 발암과정에 관여하는 종양억제유전자가 21q에 존재할 가능성을 강력히 시사한다. 21q에 존재하는 LOH의 역할을 규명하기 위해서는 향후 보다 많은 예를 대상으로 한 연구가 필요할 것으로 생각된다.