• Journal of Microbiology and Biotechnology
• /
• 제27권1호
• /
• pp.72-76
• /
• 2017

Detection of exon 19 deletion mutation in the epidermal growth factor receptor (EGFR) gene, which results in increased and sustained phosphorylation of EGFR, is important for diagnosis and treatment guidelines in non-small-cell lung cancer. Here, we have developed a simple and convenient detection system using the interaction between G-quadruplex and fluorophore thioflavin T (ThT) for discriminating EGFR exon 19 deletion mutant DNA from wild type without a label and quencher. In the presence of exon 19 deletion mutant DNA, the probe DNAs annealed to the target sequences were transformed into G-quadruplex structure. Subsequent intercalation of ThT into the G-quadruplex resulted in a light-up fluorescence signal, which reflects the amount of mutant DNA. Due to stark differences in fluorescence intensity between mutant and wild-type DNA, we suggest that the induced G-quadruplex structure in the probe DNA can report the presence of cancer-causing deletion mutant DNAs with high sensitivity.

• 한국수정란이식학회지
• /
• 제33권4호
• /
• pp.287-296
• /
• 2018

Ganglioside GM3 is known as an inhibition factor of cell differentiation and proliferation via inhibition of epidermal growth factor receptor (EGFR) phosphorylation. Our previous study showed that the exogenous ganglioside GM3 reduced the meiotic maturation of porcine oocytes and induced apoptosis at 44 h of in vitro maturation (IVM). However, the role of ganglioside GM3 in the relationship between EGFR signaling and apoptosis during porcine oocyte maturation has not yet been studied. First, porcine cumulus-oocyte complexes (COCs) were cultured in the NCSU-23 medium with exogenous ganglioside GM3 according to maturation periods (non-treated, only IVM I: 0 - 22 h, only IVM II: 22 - 44 h and IVM I & II: 0 - 44 h). We confirmed that the proportion of germinal vesicle breakdown (GVBD) increased significantly in the IVM I treated group than in the control group. We also confirmed that the meiotic maturation until M II stage and polar body formation decreased significantly in the only IVM I treated group. Cumulus cell expansion and mRNA levels of the expansion-related factors (HAS2, TNFAIP6 and PTX3) decreased significantly in the IVM I treated group than in the control group. Protein levels of EGFR, p-EGFR, ERK1/2, and p-ERK1/2 decreased significantly in the GM3-treated groups, during the IVM I period. In addition, cellular apoptosis, determined using TUNEL assay, and protein levels of Cleaved caspase 3, were increased significantly in the GM3-treated COCs during the IVM I period. Based on these results, ganglioside GM3 exposure of porcine COCs during the IVM I period reduced meiotic maturation and cumulus cell expansion via inhibition of EGFR activity in pigs.

• 동의생리병리학회지
• /
• 제35권4호
• /
• pp.117-123
• /
• 2021

Gefitinib, a first generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI), provides obvious clinical benefit in patients with EGFR-mutant non-small cell lung cancer (NSCLC). However, patients ultimately develop gefitinib resistance which mainly caused by EGFR T790M secondary mutation. In the current study, we investigated whether the root extract of Scutellaria baicalensis (SB) overcomes gefitinib resistance. Gefitinib-resistant H1975 human NSCLC cells (EGFR L858R/T790M double mutant) were treated with gefitinib and/or ethanol extract of SB (ESB) to evaluate the effect of ESB on the gefitinib sensitivity. The cell viability was measured by MTT assay and trypan blue exclusion assay. The colony-forming ability was evaluated by anchorage-dependent colony formation assay. Combined treatment with gefitinib and ESB markedly decreased the cell viability and colony formation than single treatment with gefitinib or ESB in H1975 cells. In addition, cells treated with both gefitinib and ESB exhibited a significant increase of sub-G1 DNA content which indicates apoptotic cells compared with those treated with gefitinib or ESB alone. As a molecular mechanism, combined treatment with gefitinib and ESB strongly downregulated the phosphorylation of ERK and JNK than single treatment with gefitinib or ESB. Taken together, our results demonstrate that ESB sensitizes H1975 cells to gefitinib treatment. We cautiously propose that ESB can be used in combination with gefitinib for the advanced NSCLC patients with acquired resistance to EGFR TKIs.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권8호
• /
• pp.3509-3515
• /
• 2015

Background: Diallyl disulfide (DADS) may exert potent anticancer action both in vitro and in vivo. Although its effects on cancer are significant, the underlying mechanisms remain unknown. In this study, we sought to elucidate possible links between DADS and pyruvate kinase (PKM2). Materials and Methods: $KG1{\alpha}$, a leukemia cell line highly expressing PKM2 was used with a cell counting kit (CCK)-8 and flow cytometry (FCM) to investigate the effects of DADS. Relationships between PKM2 and DADS associated with phosphorylation of EGFR, ERK1/2 and MEK, were assessed by western blot analysis. Results: In $KG1{\alpha}$ cells highly expressing PKM2, we found that DADS could affect proliferation, apoptosis and EGFR/ERK/PKM2 signaling pathways, abrogating EGF-induced nuclear accumulation of PKM2. Conclusions: These results suggested that DADS suppressed the proliferation of $KG1{\alpha}$ cells, providing evidence that its proapoptotic effects are mediated through the inhibition of EGFR/ERK/PKM2 signaling pathways.

• 대한예방한의학회지
• /
• 제15권3호
• /
• pp.127-140
• /
• 2011

Objectives : The research was conducted to confirm the effect of Acanthopanax senticosus harms(ASH) on the anti-tumor activities in AGS human gastric cancer cells. Methods : To examine the potential anti-tumor effect of ASH, we performed many experiments. After processing AGS cancer cells with varying concentrations 80% ethanol ASH extract, analyses by MTT, flow cytometer(FACS) and western blot were used. Results : AGS cancer cells showed decreased cell proliferation and increased contents of S phase when treated with ASH. Moreover, the Western blot experiment showed that ASH affected S phase cell cycle-related molecules(Cyclin A, p21 and p16) in AGS cells. ASH also inhibited EGFR-STAT3 pathway in AGS human gastric cancer cells. Conclusion : Based on these results, we observed that ASH arrested the cell cycle at S phase and inhibited the phosphorylation of EGFR and STAT3 proteins which reduce the cell cycle and the manifestation of the genes that are related to inhibiting cell growth in AGS cells. It can be concluded that ASH can be used in developing medicine for gastric cancer.

• Tuberculosis and Respiratory Diseases
• /
• 제55권1호
• /
• pp.21-30
• /
• 2003

서 론 : MUC genes의 증가와 배상세포의 증식 기전에 성장인자(growth factor)인 상피세포 성장인자 및 수용체(epidermal growth factor receptor; EGFR)가 배상세포의 증식이나 이형성에 관여한다. EGFR의 ligands 중의 한 종류인 heparin binding EGF(HB-EGF)는 세포막에 존재하는 pro-heparin binding EGF(pro-HB-EGF)로부터 유리된다. HB-EGF의 유리는 G-protein과 연관이 있다. 따라서, 본 연구는 그람 음성세균의 lipopolysaccande(LPS)에 의한 기도 점액 과생성의 기전을 밝히고, 기도점액 과분비에서 EGFR과 G-protein의 연관성을 밝혀 기도 점액 과분비 기전을 밝히고자 한다. 연구방법 : NCI-H292 세포배양에서 LPS단독 투여 또는TGF-${\alpha}$와 병합 투여한 후 MUC5AC의 당단백질을 ELISA법으로 측정하였다. LPS에 의한 MUC5AC 당단백질의 생성 기전을 밝히기 위해서 heterotrimeric G-protein 억제제인 mastoparan을 투여하고 TNF-${\alpha}$와 MUC5AC를 ELISA법으로 각각 측정하였다. MUC5AC의 생성에서 G-protein과 EGFR의 연관성을 확인하기 위하여 EGFR이 항상 발현되어 있고 MUC5AC를 분비할 수 있는 NCI-H292 세포에 G-protein 자극제인 mastoparan-7로 자극한 후 MUC5AC의 생성을 측정하였다. G-protein이 활성화하여 metalloproteinase가 세포막에 있는 HB-EGF를 유리하여 EGFR이 활성화하여 MUC5AC가 생성여부를 확인하기 위하여 ADAM10으로 NCI-H292세포에 자극하여 MUC5AC의 생성을 측정하였다. MUC5AC 생성이 EGFR과 연관성을 확인하기 위하여 특이 EGFR tyrosine kinase 억제제인 AG1478과 중화 polyclonal EGF 항체를 전처치 후 MUC5AC를 측정하였다. 결 과 : LPS의 자극에 의한 MUC5AC의 생성은 LPS 농도에 유의하게 증가 되지 않았으나, EGFR의 ligand인 TGF-${\alpha}$를 동시 투여한 경우는 LPS의 농도에 비례하여 유의하게 증가하였다. LPS의 자극은 TNF-${\alpha}$의 생성을 유의하게 증가시켰으며, G-protein 억제제인 mastoparan을 전처치한 경우는 TNF-${\alpha}$가 유의하게 감소 되었다. LPS 자극 전에 TNF-${\alpha}$ antibody, AG1478 또는 mastoparan을 전처치한 경우는 MUC5AC의 생성이 유의하게 억제되었다. MUC5AC의 생생에서 G-protein과 EGFR의 연관성에 대한 실험에서 MUC5AC의 생성이 mastoparan-7의 농도에 따라 유의하게 증가되었으며, EGF의 중화항체를 사용한 경우는 MUC5AC의 생성이 감소되었다. 또한 Matrix metalloproteinase인 ADAM10의 농도에 비례하여 MUC5AC의 생성을 증가시켰다. 결 론 : LPS에 의한 MUC5AC의 분비는 LPS가 TNF-${\alpha}$를 생성시키고, TNF-${\alpha}$가 EGFR의 발현을 유도하여 MUC5AC가 분비되었다. 또한 MUC5AC의 생성에 있어서 G-protein의 활성은 matrix metalloproteinase에 의하여 EGFR의 ligand 인 HB-EGF가 유리되어 EGFR의 transacti vation으로 MUC5AC가 생성되는 것으로 사료된다.

• Journal of Ginseng Research
• /
• 제43권4호
• /
• pp.527-538
• /
• 2019

Background: Ginsenoside Rg1 was shown to exert ligand-independent activation of estrogen receptor (ER) via mitogen-activated protein kinase-mediated pathway. Our study aimed to delineate the mechanisms by which Rg1 activates the rapid ER signaling pathways. Methods: ER-positive human breast cancer MCF-7 cells and ER-negative human embryonic kidney HEK293 cells were treated with Rg1 ($10^{-12}M$, $10^{-8}M$), $17{\beta}$-estradiol ($10^{-8}M$), or vehicle. Immunoprecipitation was conducted to investigate the interactions between signaling protein and ER in MCF-7 cells. To determine the roles of these signaling proteins in the actions of Rg1, small interfering RNA or their inhibitors were applied. Results: Rg1 rapidly induced $ER{\alpha}$ translocation to plasma membrane via caveolin-1 and the formation of signaling complex involving linker protein (Shc), insulin-like growth factor-I receptor, modulator of nongenomic activity of ER (MNAR), $ER{\alpha}$, and cellular nonreceptor tyrosine kinase (c-Src) in MCF-7 cells. The induction of extracellular signal-regulated protein kinase and mitogen-activated protein kinase kinase (MEK) phosphorylation in MCF-7 cells by Rg1 was suppressed by cotreatment with small interfering RNA against these signaling proteins. The stimulatory effects of Rg1 on MEK phosphorylation in these cells were suppressed by both PP2 (Src kinase inhibitor) and AG1478 [epidermal growth factor receptor (EGFR) inhibitor]. In addition, Rg1-induced estrogenic activities, EGFR and MEK phosphorylation in MCF-7 cells were abolished by cotreatment with G15 (G protein-coupled estrogen receptor-1 antagonist). The increase in intracellular cyclic AMP accumulation, but not Ca mobilization, in MCF-7 cells by Rg1 could be abolished by G15. Conclusion: Ginsenoside Rg1 exerted estrogenic actions by rapidly inducing the formation of ER containing signalosome in MCF-7 cells. Additionally, Rg1 could activate EGFR and c-Src ER-independently and exert estrogenic effects via rapid activation of membrane-associated ER and G protein-coupled estrogen receptor.

• Biomolecules & Therapeutics
• /
• 제32권1호
• /
• pp.104-114
• /
• 2024

Licochalcone C (LCC; PubChem CID:9840805), a chalcone compound originating from the root of Glycyrrhiza inflata, has shown anticancer activity against skin cancer, esophageal squamous cell carcinoma, and oral squamous cell carcinoma. However, the therapeutic potential of LCC in treating colorectal cancer (CRC) and its underlying molecular mechanisms remain unclear. Chemotherapy for CRC is challenging because of the development of drug resistance. In this study, we examined the antiproliferative activity of LCC in human colorectal carcinoma HCT116 cells, oxaliplatin (Ox) sensitive and Ox-resistant HCT116 cells (HCT116-OxR). LCC significantly and selectively inhibited the growth of HCT116 and HCT116-OxR cells. An in vitro kinase assay showed that LCC inhibited the kinase activities of EGFR and AKT. Molecular docking simulations using AutoDock Vina indicated that LCC could be in ATP-binding pockets. Decreased phosphorylation of EGFR and AKT was observed in the LCC-treated cells. In addition, LCC induced cell cycle arrest by modulating the expression of cell cycle regulators p21, p27, cyclin B1, and cdc2. LCC treatment induced ROS generation in CRC cells, and the ROS induction was accompanied by the phosphorylation of JNK and p38 kinases. Moreover, LCC dysregulated mitochondrial membrane potential (MMP), and the disruption of MMP resulted in the release of cytochrome c into the cytoplasm and activation of caspases to execute apoptosis. Overall, LCC showed anticancer activity against both Ox-sensitive and Ox-resistant CRC cells by targeting EGFR and AKT, inducing ROS generation and disrupting MMP. Thus, LCC may be potential therapeutic agents for the treatment of Ox-resistant CRC cells.

• Journal of Microbiology and Biotechnology
• /
• 제24권2호
• /
• pp.152-159
• /
• 2014

The regulation of protein tyrosine phosphorylation is mediated by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs) and is essential for cellular homeostasis. Co-expression of PTKs with PTPs in Pichia pastoris was used to facilitate the expression of active PTKs by neutralizing their apparent toxicity to cells. In this study, the gene encoding phosphatase PTP1B with or without a blue fluorescent protein or peroxisomal targeting signal 1 was cloned into the expression vector pAG32 to produce four vectors. These vectors were subsequently transformed into P. pastoris GS115. The tyrosine kinases EGFR-2 and $PDGFR{\beta}$ were expressed from vector pPIC3.5K and were fused with a His-tag and green fluorescent protein at the N-terminus. The two plasmids were transformed into P. pastoris with or without PTP1B, resulting in 10 strains. The EGFR-2 and $PDGFR{\beta}$ fusion proteins were purified by $Ni^{2+}$ affinity chromatography. In the recombinant P. pastoris, the PTKs co-expressed with PTP1B exhibited higher kinase catalytic activity than did those expressing the PTKs alone. The highest activities were achieved by targeting the PTKs and PTP1B into peroxisomes. Therefore, the EGFR-2 and $PDGFR{\beta}$ fusion proteins expressed in P. pastoris may be attractive drug screening targets for anticancer therapeutics.

• Journal of Microbiology and Biotechnology
• /
• 제27권1호
• /
• pp.49-56
• /
• 2017

In the human airway, mucus exists to protect the respiratory system as a primary barrier of the innate immune system. However, hyperexpressed mucus limits airflow, resulting in a decrease of lung function. Among more than 20 mucin family members, MUC5AC and MUC5B are major glycoproteins in human airway mucus. The epidermal growth factor receptor (EGFR) signaling pathway is one of the mechanisms of these mucins expression and specificity protein-1 (Sp1) transcription factor is the downstream signal of this pathway, playing pivotal roles in mucin expression. Even though there are some drugs for treating mucus hypersecretion, no drug has proven effects on humans. We found that the flavonoid tilianin regulated MUC5AC expression and also inhibited Sp1 phosphorylation. In this study, we investigated how tilianin would modulate EGFR signaling and regulate mucin production. In conclusion, tilianin inhibited MUC5AC expression mediated via modulating the EGFR-MEK-ERK-Sp1 signaling pathway in NCI-H292 human airway epithelial cells. This study may provide the basis for the novel treatment of mucus hypersecretion.