• BMB Reports
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• v.55 no.12
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• pp.645-650
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• 2022

Epithelial-to-mesenchymal transition (EMT)-subtype gastric cancers have the worst prognosis due to their higher recurrence rate, higher probability of developing metastases and higher chemo-resistance compared to those of other molecular subtypes. Pharmacologically actionable somatic mutations are rarely found in EMT-subtype gastric cancers, limiting the utility of targeted therapies. Here, we conducted a high-throughput chemical screen using 37 gastric cancer cell lines and 48,467 synthetic small-molecule compounds. We identified YK-135, a small-molecule compound that showed higher cytotoxicity toward EMT-subtype gastric cancer cell lines than toward non-EMT-subtype gastric cancer cell lines. YK-135 exerts its cytotoxic effects by inhibiting mitochondrial complex I activity and inducing AMP-activated protein kinase (AMPK)-mediated apoptosis. We found that the lower glycolytic capacity of the EMT-subtype gastric cancer cells confers synthetic lethality to the inhibition of mitochondrial complex I, possibly by failing to maintain energy homeostasis. Other well-known mitochondrial complex I inhibitors (e.g., rotenone and phenformin) mimic the efficacy of YK-135, supporting our results. These findings highlight mitochondrial complex I inhibitors as promising therapeutic agents for EMT-subtype gastric cancers and YK-135 as a novel chemical scaffold for further drug development.

• Journal of Digestive Cancer Research
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• v.10 no.1
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• pp.9-15
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• 2022

Proton pump inhibitors (PPIs), a potent gastric acid inhibitor, are widely used in gastric acid-related diseases such as gastroesophageal reflux disease and peptic ulcer, and are known as the most frequently used drugs worldwide. However, as the frequency of use increases, the number of cases of long-term PPI therapy without clear indications is increasing. Recently, there have been concerns about the risk of gastric cancer in patients with long-term PPI users. Potential mechanisms for the association between PPI and gastric cancer include enterochromaffin-like cell proliferation due to hypergastrinemia caused by gastric acid suppression, progression of atrophic gastritis, and corpus-predominant type through interaction with Helicobacter pylori (H. pylori) infection. Several epidemiologic studies showed controversial results on the issue, and it is difficult to prove a causal relationship between PPI and gastric cancer. Nevertheless, long-term PPI should be administered cautiously based on individual risk-benefit profile, specifically among those with history of H. pylori infection, in high-risk region of gastric cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.127-131
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• 2013

Trastuzumab is the first molecular targeting drug to increase the overall survival rate in advanced gastric cancer. However, it has also been found that a high intrinsic or primary trastuzumab resistance exists in some proportion of gastric cancer patients. In order to explore the mechanism of resistance to trastuzumab, firstly we investigated the expression of MUC1 (membrane-type mucin 1) in gastric cancer cells and its relationship with drug-resistance. Then using gene-silencing, we transfected a siRNA of MUC1 into drug-resistant cells. The results showed the MKN45 gastric cell line to be resistant to trastuzumab, mRNA and protein expression of MUC1 being significantly upregulated. After transfection of MUC1 siRNA, protein expression of MUC1 in MKN45cells was significantly reduced. Compared with the junk transfection and blank control groups, the sensitivity to trastuzumab under MUC1 siRNA conditions was significantly increased. These results imply that HER2-positive gastric cancer cell MKN45 is resistant to trastuzumab and this resistance can be cancelled by silencing expression of the MUC1 gene.

• Biomolecules & Therapeutics
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• v.28 no.4
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• pp.370-379
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• 2020

Econazole, a potent broad-spectrum antifungal agent and a Ca²⁺ channel antagonist, induces cytotoxicity in leukemia cells and is used for the treatment of skin infections. However, little is known about its cytotoxic effects on solid tumor cells. Here, we investigated the molecular mechanism underlying econazole-induced toxicity in vitro and evaluated its regulatory effect on the metastasis of gastric cancer cells. Using the gastric cancer cell lines AGS and SNU1 expressing wild-type p53 we demonstrated that econazole could significantly reduce cell viability and colony-forming (tumorigenesis) ability. Econazole induced G0/G1 phase arrest, promoted apoptosis, and effectively blocked proliferation- and survival-related signal transduction pathways in gastric cancer cells. In addition, econazole inhibited the secretion of matrix metalloproteinase- 2 (MMP-2) and MMP-9, which degrade the extracellular matrix and basement membrane. Econazole also effectively inhibited the metastasis of gastric cancer cells, as confirmed from cell invasion and wound healing assays. The protein level of p53 was significantly elevated after econazole treatment of AGS and SNU1 cells. However, apoptosis was blocked in econazole-treated cells exposed to a p53-specific small-interfering RNA to eliminate p53 expression. These results provide evidence that econazole could be repurposed to induce gastric cancer cell death and inhibit cancer invasion.

• Journal of Microbiology and Biotechnology
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• v.11 no.5
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• pp.876-879
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• 2001

${\gamma}$ -Tubulin is an essential component involved in microtubule nucleation. The present work examined whether the fast proliferation of cancer cells can be retarded by the depletion of ${\gamma}$ -tubulin expression. Two different gastric cancer cell lines and one control cell line were treated with antisence oligonucleotides complementary to the messenger RNA of ${\gamma}$ -tubulin. The$[^3H]$ -thymidine incorporation in the two gastric cancer cell lines, SNU-1 and SNU-216, was dramatically reducd by treatment with the ${\gamma}$ -tubulin antisense oligonucleotides in a dosage-dependent manner. In contrast, the control cell line, NIH/3T3, showed no significant effect from the antisense oligonucleotides even at a high concentration. The ablation of ${\gamma}$ -tubulin expression in the tumor cells resulted in an altered DNA synthesis during mitosis and it decreased the cell progression. Accordingly, the use of antisense oligonucleotides may be an effective way of inhibiting the proliferation of human gastric cancers.

• Journal of Digestive Cancer Research
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• v.3 no.1
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• pp.26-29
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• 2015

A 73-year-old male visited our hospital with a complaint of general weakness. He underwent pyloric preserving pancreas-toduodenectomy due to ampullary cancer three years ago. Abdominal computed tomography scan at initial visit revealed multiple hepatic masses. A PET-CT scan showed multiple FDG uptakes at whole liver. He underwent hepatic artery infusion chemotherapy (HAIC) for five cycles. During the first cycle of HAIC, he developed gastric ulcer bleeding and endoscopic hemostasis was done successfully. Esophagogastroduodenoscopy after the 5^th cycle of HAIC revealed ulcer scar at gastric angle. PET-CT scan at 12 months showed no FDG uptake at liver, but a focal FDG uptakes at stomach and peri-gastric lymph nodes were newly developed. Esophagogastroduodenoscopy revealed about 3 cm sized mass at gastric angle. He underwent surgery and pathologic examination revealed large cell neuroendocrine carcinoma. We report a case of gastric large cell neuroendocrine carcinoma with liver metastasis treated with HAIC followed by surgery.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.16
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• pp.6849-6853
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• 2014

Multidrug resistance (MDR) is a major impediment to successful chemotherapy of gastric cancer. Our aim was to establish an epirubicin-resistant cell subline (AGS/EPI) and to elucidate the mechanisms involved in acquired EPI resistance. The AGS/EPI cell subline developed by exposing parental AGS cells to stepwise increasing concentrations of EPI demonstrated 2.52-fold resistance relative to the AGS cell line, and mRNA expression of the ATP-dependent drug-efflux pump P-glycoprotein (Pgp), more recently known as ABCB1 protein, was similarly upregulated. An AGS/EPI cell subline could thus be effectively established, and MDR mechanism of these cells was shown to be related to the overexpression of mRNA of the ABCB1 gene.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5583-5586
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• 2014

Helicobacter pylori (H. pylori) infection induces apoptosis in gastric epithelial cells, and this occurrence may link to gastric carcinogenesis. However, the regulatory mechanism of H. pylori-induced apoptosis is not clear. MicroRNA-146a has been implicated as a key regulator of the immune system. This report describes our discovery of molecular mechanisms of microRNA-146a regulation of apoptosis in human gastric cancer cells. We found that overexpression of microRNA-146a by transfecting microRNA-146a mimics could significantly enhance apoptosis, and this upregulation was triggered by COX-2 inhibition. Furthermore, we found that microRNA-146a density was positively correlated with apoptosis rates in H. pylori-positive gastric cancer tissues and intratumoral microRNA-146a density was negatively correlated with lymph node metastasis among H. pylori-positive gastric cancer patients. Understanding the important roles of microRNA-146a in regulating cell apoptosis in H. pylori infected human gastric cancer cells will contribute to the development of microRNA targeted therapy in the future.

• Korean Journal of Pharmacognosy
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• v.49 no.3
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• pp.225-230
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• 2018

3',4'-Disenecioylkhellactone is one of khellactone-type coumarins isolated from the roots of Peucedanum japonicum Thunb. However, its pharmacological effects are still little understood. In the present study, we investigated the inhibitory effect of 3',4'-disenecioylkhellactone on growth of gastric cancer cells. 3',4'-Disenecioylkhellactone strongly suppressed cell proliferation and induced caspase-mediated apoptosis in AGS human gastric cancer cells. Analysis of phospho-antibody arrays revealed 3',4'-disenecioylkhellactone effectively suppressed signal transducer and activator of transcription 3 (STAT3) tyrosine phosphorylation. 3',4'-Disenecioylkhellactone decreased STAT3 translocation to the nucleus and expression of STAT3 target genes. In addition, we examined the level of STAT3 activation in several gastric cancer cells and found that the inhibition of STAT3 phosphorylation by 3',4'-disenecioylkhellactone was associated with gastric cancer cell proliferation. Taken together, this study provides evidence for the first time that 3',4'-disenecioylkhellactone may be a potential therapeutic agent for the prevention or treatment of gastric cancer.

• Journal of Gastric Cancer
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• v.24 no.1
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• pp.29-56
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• 2024

In recent years, remarkable progress has been made in the molecular profiling of gastric cancer. This progress has led to the development of various molecular classifications to uncover subtype-specific dependencies that can be targeted for therapeutic interventions. Human epidermal growth factor receptor 2 (HER2) is a crucial biomarker for advanced gastric cancer. The recent promising results of novel approaches, including combination therapies or newer potent agents such as antibody-drug conjugates, have once again brought attention to anti-HER2 targeted treatments. In HER2-negative diseases, the combination of cytotoxic chemotherapy and programmed cell death-1/programmed cell death ligand-1 (PD-1/PD-L1) inhibitors has become the established standard of care in first-line settings. In the context of gastric cancer, potential biomarkers such as PD-L1 expression, Epstein-Barr virus, microsatellite instability, and tumor mutational burden are being considered for immunotherapy. Recently, promising results have been reported in studies on anti-Claudin18.2 and fibroblast growth factor receptor 2 treatments. Currently, many ongoing trials are aimed at identifying potential targets using novel approaches. Further investigations will be conducted to enhance the progress of these therapies, addressing challenges such as primary and acquired resistance, tumor heterogeneity, and clonal evolution. We believe that these efforts will improve patient prognoses. Herein, we discuss the current evidence of potential targets for systemic treatment, clinical considerations, and future perspectives.