• Biomolecules & Therapeutics
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• v.31 no.2
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• pp.200-209
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• 2023

Patients with non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) amplification or sensitive mutations initially respond to the tyrosine kinase inhibitor gefitinib, however, the treatment becomes less effective over time by resistance mechanism including mesenchymal-epithelial transition (MET) overexpression. A therapeutic strategy targeting MET and EGFR may be a means to overcoming resistance to gefitinib. In the present study, we found that picropodophyllotoxin (PPT), derived from the roots of Podophyllum hexandrum, inhibited both EGFR and MET in NSCLC cells. The antitumor efficacy of PPT in gefitinib-resistant NSCLC cells (HCC827GR), was confirmed by suppression of cell proliferation and anchorage-independent colony growth. In the targeting of EGFR and MET, PPT bound with EGFR and MET, ex vivo, and blocked both kinases activity. The binding sites between PPT and EGFR or MET in the computational docking model were predicted at Gly772/Met769 and Arg1086/Tyr1230 of each ATP-binding pocket, respectively. PPT treatment of HCC827GR cells increased the number of annexin V-positive and subG1 cells. PPT also caused G2/M cell-cycle arrest together with related protein regulation. The inhibition of EGFR and MET by PPT treatment led to decreases in the phosphorylation of the downstream-proteins, AKT and ERK. In addition, PPT induced reactive oxygen species (ROS) production and GRP78, CHOP, DR5, and DR4 expression, mitochondrial dysfunction, and regulated involving signal-proteins. Taken together, PPT alleviated gefitinib-resistant NSCLC cell growth and induced apoptosis by reducing EGFR and MET activity. Therefore, our results suggest that PPT can be a promising therapeutic agent for gefitinib-resistant NSCLC.

• Journal of Life Science
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• v.19 no.8
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• pp.1073-1080
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• 2009

A number of studies have demonstrated that the regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce the risks of colorectal, oesophageal and lung cancers. NSAIDs have been shown to exert their anti-cancer effects through inducing apoptosis in cancer cells. The susceptibility of tumor cells to anti-tumor drug-induced apoptosis appears to depend on the balance between pro-apoptotic and anti-apoptotic programs such as nuclear factor kB (NF-kB), phosphatidylinositol 3-kinase (PI3K)-Akt/protein kinase B (PKB) and MEK1/2-ERK1/2 pathways. We examined the effects of pro-survival PI3K and ERK1/2 signal pathways on cell cycle arrest and apoptosis in response to NSAIDs including sulindac sulfide and NS398. We show that simultaneous inhibition of the Akt/PKB and ERK1/2 signal cascades could synergistically enhance the potential pro-apoptotic activities of sulindac sulfide and NS398. Similar enhancement was observed in cells treated with sulindac sulfide or NS398 and 100 ${\mu}$M genistein, an inhibitor of receptor tyrosine kinases (RTKs) that are upstream of PI3K and MEK1/2 signaling. We further demonstrate that NAG-1 is induced and plays a critical role(s) in apoptosis by NSAIDs-based combined treatment. In sum, our results show that combinatorialtreatment of sulindac sulfide or NS398 and genistein results in a highlysynergistic induction of apoptotic cell death to increase the chemopreventive effects of the NSAIDs, sulindac sulfide and NS398.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.186-186
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• 1994

Many agonists have been known to activate the hydrolysis of membrane phospholipids through the bindings with corresponding receptors on the various cells. Diacylglycerol and inositol 1,4,5-trisphosphate(IP3) generated by the action of phosphoinositide-specific phospholipase C (PI-PLC) are well known second messengers for the activation of protein kinase C and the mobilization of Ca2+ in many cells. Three types of PI-PLC isozyme (${\alpha}$,${\gamma}$, and $\delta$) and several subtrpes for each type have been identified from mammalian sources by purification of enzymes and cloning of their cDNAs. Each type PI-PLC isozyme is coupled to different receptors and mediators, for example, ${\beta}$-types are coupled to the seven-transmembrane-receptors via Gq family of G-proteins and ${\beta}$-types directly to the receptor tyrosine kinases. Specific modulators for the signaling pathway through each type of PI-PLC should be very useful as potential potential candidates for lend substances in developing novel drugs. To establish the sensitive and convenient screening systems for searching modulators on PI-PLC mediated signaling, two kinds of approaches have been tried. (1) Establishment of in vitro assay condition for each type of PI-PLC isozyme: Overexpression by using vaccinia virus and purification of each isozyme was carried out for the preparation of large amounts of enaymes. Optimum and sensitive assay condition for the measurements of PI-ELC activities were established. (2) Development of the cell lines in which each type of PI-PLC is permanently overexpressed: A fibroblast cell line (3T3${\gamma}$1-7) in which PI-PLC-${\gamma}$1 was overexpressed by using pZip-neo expression vector was developed and used for the measurement of PDGF-induced IP3 formation. The responses for IP3 formed in 3T3${\gamma}$1-7 cells by the treatment of PDGF is 8 times more sensitive than those in control cells. 3T3${\gamma}$l-7 cell is useful for the screening of the inhibitors on the PDGF-induced cellular responses from large number of samples in a small volume(50 ${\mu}$l) and short time(5-15 min). Using these systems, we screened hundreds of herb-extracts for the inhibition of PDGF-induced IP3 formation and selected several extracts that showed the inhibition as the candidates for isolation and characterization of active substances. The determination of the acting point of selected extracts or fractions in the PDGF signaling pathway has been analyzing.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.2
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• pp.83-87
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• 2008

The fyn-related kinase (FRK) belongs to the tyrosine kinase family of protein kinases. Recent studies have shown that Frk affects pancreatic beta cell number during embryogenesis and promotes beta cell cytotoxic signals in response to streptozotocin. To investigate the genetic association between FRK polymorphisms and the risk of obesity in Korean population, single nucleotide polymorphisms (SNPs) in the FRK gene region were selected and analyzed. The body mass index (BMI) was calculated, and biochemical data (systolic blood pressure, diastolic blood pressure, hemoglobin A1C, triglyceride, total cholesterol, high density lipoprotein, and low density lipoprotein) of blood sample from each subject were also measured. One hundred fifty five healthy control and 204 overweight/obesity subjects were recruited. Genotype frequencies of six SNPs [rs6568920 (+8391G>A), rs3756772 (+56780A>G), rs3798234 (+75687C>T), rs9384970 (+68506G>A), rs1933739 (+72978G>A), and rs9400883 (+75809A>G)] in the FRK gene were determined by Affymetrix Targeted Genotyping Chip data. According to the classification of Korean Society for the Study of Obesity, control (BMI 18 to < 23) and overweight/obesity (BMI$\geq$23) subjects were recruited. For the analysis of genetic data, EM algorithm, SNPStats, Haploview, HapAnalyzer, SNPAnalyzer, and Helixtree programs were used. Multiple logistic regression analysis (codominant, dominant, and recessive models) was performed. Age and gender as covariates were adjusted. For biochemical data, Student's t test was used. The mean value of BMI in the control and overweigh/obesity groups was 21.1${\pm}$1.2 (mean${\pm}$SD) and 25.6${\pm}$2.0, respectively. All biochemical data of the overweight/obesity group were statistically significance, compared with the control group. Among six SNPs, two linkage disequilibrium (LD) blocks were discovered. One block consisted of rs1933739 and rs9400883, and the other comprised rs3756772 and rs3798234. One SNP (rs9384970, +68506G>A) showed an association with overweight/obesity in the codominant model (p=0.03). Interestingly, the AA genotype distribution in the overweight/obesity group (n=7, 3.5%) was higher than those in the control group (n=1, 0.6%), which is not found in either Japanese or Chinese subjects. Therefore, the AA genotype of rs9384970 may be a risk factor for development of obesity in Korean population. The results suggest that FRK may be associated with overweight/obesity in Korean population.

• Journal of Life Science
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• v.12 no.2
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• pp.164-172
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• 2002

Breast cancer cell lines display a wide variety of growth factor receptors, and considerable evidences implicate the importance of signalings from those receptors. A useful prognostic indicator would be the level of activity of a second messenger protein used in common by these receptors. Our studies were designed to obtain preliminary information on the possible role of polyamine as a mediator of the membrane-associated protein phosphorylation and as a regulator of second messenger in mitogenic signal of estrogen or growth factors in MCF-7 human breast lancer cells. DFMO significantly inhibited the phosphorylation induced by $E_2$, TGF-$\alpha$ and EGF in membrane-associated proteins (154, 134, 116, and 104 kDa). Exogenous polyamines abolished the inhibitory effect of DFMO. Tyrosine phosphorylations of membrane-associated proteins were not increased by $E_2$ or growth factor treatments and not affected DFMO treatment. Polyamine administration markedly enhanced the tyrosine phosphorylation of membrane-associated proteins (154, 134, and 116 kDa). In the present study, $E_2$ and TGF-$\alpha$ and EGF enhanced protein phosphorylation in the almost same levels. These data indicate that $E_2$ and growth factor signaling pathway may cross-talk through various protein kinase which phosphorylated many substrate proteins (154, 134, 116 and 104 kDa). Polyamines may be involved in growth signaling pathway of $E_2$ and TGF-$\alpha$ or EGF for the cross-talk through regulation of the protein phosphorylation such as 154, 134, 116 and 104 kDa. Polyamine may also selectively interfere with several different protein kinases, and the specific steps in signal transduction system were effected by polyamines.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7367-7369
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• 2013

Background: Inoperable and metastatic hepatocellular carcinoma (HCC) is associated with a poor prognosis and low chemotherapeutic efficiency. Sorafenib is an oral multi-kinase inhibitor exerting its effects via the RAF/MEK/ERK pathway, vascular endothelial growth factor receptor (VEGFR) and platelet derived growth factor receptor beta (PDGFR-${\beta}$) tyrosine kinases. Randomized studies have shown a significant contribution of sorafenib to life expectancy and quality of life of cancer patients. The aim of the present study is to evaluate the efficacy and side effects of sorafenib therapy in Turkey. Materials and Methods: Data for 103 patients (82 males, 21 females) receiving sorafenib therapy in 13 centers from February 2008 to December 2012 were evaluated. Median age was 61 years and median ECOG performance status was 1 (range: 0-2). 60 patients (58%) had hepatitis B, 15 patients (15%) had hepatitis C infection and 12 patients (12%) had a history of alcohol consumption. All of the patients had Child scores meeting the utilization permit of the drug in our country (Child A). Results: A total of 571 cycles of sorafenib therapy were administered with a median of four per patient. Among the evaluable cases, there was partial response in 15 (15%), stable disease in 52 (50%), and progressive disease in 36 (35%). Median progression-free survival was 18 weeks and median overall survival was 48 weeks. The dose was reduced only in 6 patients and discontinued in 2 patients due to grade 3-4 toxicity, 18 patients (17%) suffering hand-foot syndrome, 7 (7%) diarrhea, and 2 (2%) vomiting. Conclusions: This retrospective study demonstrated better efficacy of sorafenib therapy in patients with advanced HCC compared to the literature while progression-free survival and overall survival findings were comparable. The side effect rates indicate that the drug was tolerated well. In conclusion, among the available treatment options, sorafenib is an efficient and tolerable agent in patients with inoperable or metastatic HCC.