• Archives of Pharmacal Research
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• v.29 no.11
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• pp.1018-1023
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• 2006

Chemoresistance remains the major obstacle to successful therapy of cancer. In order to understand the mechanism of multidrug resistance (MDR) that is frequently observed in lung cancer patients, here we studied the contribution of MDR-related proteins by establishing lung cancer cell lines with acquired resistance against etoposide. We found that human H460 lung cancer cells responded to etoposide more sensitively than A549 cells. Among MDR-related proteins, the expression of p-glycoprotein (Pgp) and lung resistance protein (LRP) were much higher in A549 cells compared with that in H460 cells. When we established H460-R1 and -R2 cell lines by progressive exposure of H460 cells to increasing doses of etoposide, the response against etopbside as well as doxorubicin was greatly reduced in R1 and R2 cells, suggesting MDR induction. Induction of MDR was not accompanied by a decrease in the intracellular accumulation of etoposide and the expression of MDR-related proteins that function as drug efflux pumps such as Pgp and MRP1 was not changed. We found that the acquired resistance paralleled an increased expression of LRP in H460 cells. Taken together, our data suggest the implicative role of LRP in mediating MDR in lung cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3093-3097
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• 2014

Background: Cancer is a major threat to the public health whether in developed or in developing countries. As the most common primary malignant tumor, the morbidity and mortality rate of lung cancer continues to rise in recent ten years worldwide. Chemotherapy is one of the main methods in the treatment of lung cancer, but this is hampered by chemotherapy drug resistance, especially MDR. As a component of the 60S large ribosomal subunit, ribosomal protein L39-L gene was reported to be expressed specifically in the human testis and human cancer samples of various tissue origins. Materials and Methods: Total RNA of cultured drug-resistant and susceptible A549 cells was isolated, and real time quantitative RT-PCR were used to indicate the transcribe difference between amycin resistant and susceptible strain of A549 cells. Viability assay were used to show the amycin resistance difference in RPL39-L transfected A549 cell line than control vector and null-transfected A549 cell line. Results: The ribosomal protein L39-L transcription level was 8.2 times higher in drug-resistant human lung cancer A549 cell line than in susceptible A549 cell line by quantitative RT-PCR analysis. The ribosomal protein L39-L transfected cells showed enhanced drug resistance compared to plasmid vector-transfected or null-transfected cells as determined by methyl tritiated thymidine (3H-TdR) incorporation. Conclusions and Implications for Practice: The ribosomal protein L39-L gene may have effects on the drug resistance mechanism of lung cancer A549 cells.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4635-4639
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• 2013

Multi-drug resistance (MDR) is an essential aspect of human lung cancer chemotherapy failure. Recent studies have shown that vinorelbine is involved in underlying processes in human tumors, reversing the MDR inseveral types of cancer cells. However, the roles and potential mechanism are not fully clear. In this study, we explored effects of vinorelbine in multi-drug resistance reversal of human lung cancer A549/DDP cells. We found that vinorelbine increased drug sensitivity to cisplatin and intracellular accumulation of rhodamine-123, while decreasing expression of P-glycoprotein (P-gp), multi-drug resistance-associated protein (MRP1) and glutathione-S-transferase ${\pi}$ (GST-${\pi}$) in A549/DDP cells. At the same time, we also established downregulation of p-Akt and decreased transcriptional activation of NF-${\kappa}B$ and twist after vinorelbine treatment. The results indicated that vinorelbine might be used as a potential therapeutic strategy in human lung cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2425-2430
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• 2015

Clinical resistance to chemotherapeutic agents is one of the major hindrances in the treatment of human cancers. EHZ2 is involved in drug resistance and is overexpressed in drug-resistant cancer cell lines. In this study, we investigated the effects of EHZ2 on cisplatin -resistance in A549/DDP and AGS/DDP cells. EHZ2 mRNA and protein were found to be significantly overexpressed in A549/DDP and AGS/DDP cells, compared to parental cells. EHZ2 siRNA successfully silenced EHZ2 mRNA and protein expression. Proliferation was inhibited and drug resistance to cisplatin was improved. Flow cytometry showed that silencing of EHZ2 arrested A549/DDP and AGS/DDP cells in the G0/G1 phase, increasing apoptosis, rh-123 fluorescence intensity and caspase-3/8 activities. Silencing of EHZ2 also significantly reduced the mRNA and protein expression levels of cyclin D1 and MDR1,while up-regulating p15, p21, p27 and miR-218 in A549/DPP cells. Furthermore, silencing of EHZ2 also significantly increased the expression level of tumor suppressor factor miR-218. We also found down-regulating EHZ2 expression increased methylation in A549/DDP and AGS/DDP cells. This study demonstrates that drug resistance can be effectively reversed in human cisplatin-resistant lung and gastric cancer cells through delivery of siRNAs targeting EHZ2.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3191-3194
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• 2014

Adenocarcinoma of lung has high incidence and a poor prognosis, woith chemotherapy as the main therapeutic tool, most commonly with cisplatin. However, chemotherapy resistance develops in the majority of patients during clinic treatment. Mechanisms of resistance are complex and still unclear. Although annexin play important roles in various tumor resistance mechanisms, their actions in cisplatin-resistant lung adenocarcinoma remain unclear. Preliminary studies by our group found that in cisplatin-resistant lung cancer A549 cells and lung adenocarcinoma tissues, both mRNA and protein expression of annexins A1, A2 and A3 is increased. Using a library of annexin A1, A2 and A3 targeting combined molecules already established by ourselves we found that specific targeting decreased cisplatin-resistance. Taken together, the underlined effects of annexins A1, A2 and A3 on drug resistance and suggest molecular mechanisms in cisplatin-resistant A549 cells both in vivo and in vitro. Furthermore, the study points to improved research on occurrence and development of lung adenocarcinoma, with provision of effective targets and programmes for lung adenocarcinoma therapy in the clinic.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1294-1298
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• 2014

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer representing 85% of lung cancer patients. Despite several EGFR-targeted drugs have been developed in the treatment of NSCLC, the clinical efficacy of these EGFR-targeted therapies is being challenged by the occurrence of drug resistance. In this regard, Hsp90 represents great promise as a therapeutic target of cancerous diseases due to its role in modulating and stabilizing numerous oncogenic proteins. Accordingly, inhibition of single Hsp90 protein simultaneously disables multiple signaling networks so as to overcome drug resistance in cancer. In this study, we synthesized a series of 11 butein analogues and evaluated their biological activities against gefitinibresistant NSCLC cells (H1975). Our study indicated that analogue 1h inhibited the proliferation of H1975 cells, down-regulated the expression of Hsp90 client proteins, including EGFR, Met, Her2, Akt and Cdk4, and upregulated the expression of Hsp70. The result suggested that compound 1h disrupted Hsp90 chaperoning function and could serve a potential lead compound to overcome the drug resistance in cancer chemotherapy.

• Toxicological Research
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• v.18 no.4
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• pp.411-416
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• 2002

Apoptosis, or programmed cell death, is a genetically regulated pathway that is altered in many cancers. Overexpression of bcl-2 leads to resistance to apoptosis and promotes tumorigenesis. To determine the effect of bcl-2 antisense treatment in human lung cancer cell lines, a 20 mer full phosphorothioate oligonucleotide (ODN) targeted at the coding region of the bcl-2 mRNA was synthesized. Western blot analyses were used to examine bcl-2 protein level in five human non-small cell lung cancer (NSCLC) cell lines (NCI-H226, SK-MES-1 NCI-H358, NCI-H522 and NCI-Hl 299) and four human small cell lung cancer (SCLC) cell lines (NCI-H69, NCI-H4l7, HCC-2108 and SW2). Three out of five NSCLC (NCI-H226, SK-MES-1 and NCI-Hl 299) and all of SCLC cell lines expressed Bcl-2 protein. Treatment of these cell with antisense ODN for 48 hours reduced their viability and Bcl-2 protein level. As a conclusion, bcl-2 antisense treatment appears reduction of the Bcl-2 protein levels and cytotoxic effect including apoptosis in human lung cancer cell lines.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.1
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• pp.61-66
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• 2014

Lung cancer is still the number one cause of death from cancer worldwide. The clinical effect of platinum-based chemotherapy for non-small cell lung cancer is constrained by the resistance to drug. To overcome chemo-resistance, various modified treatment including combination therapy has been used, but overall survival has not been improved yet. In this study, chemo-resistant lung cancer cells, A549/Cis and H460/Cis, were developed by long-term exposure of cells to cisplatin and the proliferative capability of these resistant cells was verified to be reduced. We found cytotoxic effect of epigallocatechin gallate (EGCG), a major catechin derived from green tea, on both the parental lung cancer cells, A549 and H460, and their cisplatin resistant cells, A549/Cis and H460/Cis. ELISA and Western blot analysis revealed that EGCG was able to increase interlukine-6 (IL-6) production per cell, whereas its downstream effector Signal transducers and activators of transcription 3 (STAT3) phosphorylation was not changed by EGCG, indicating that IL-6/STAT3 axis is not the critical signaling to be inhibited by EGCG. We next found that EGCG suppresses the expression of both Axl and Tyro 3 receptor tyrosine kinases at mRNA and protein level, explaining the cytotoxic effect of EGCG on lung cancer cells, especially, regardless of cisplatin resistance. Taken together, these data suggest that EGCG impedes proliferation of lung cancer cells including their chemo-resistant variants through downregulation of Axl and Tyro 3 expression.

• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1737-1740
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• 2011

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6321-6326
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• 2013

Introduction: Lung cancer is extremely harmful to human health and has one of the highest worldwide incidences of all malignant tumors. Approximately 80% of lung cancers are classified as non-small cell lung cancers (NSCLCs). Cisplatin-based multidrug chemotherapy regimen is standard for such lesions, but drug resistance is an increasing problem. F-box/WD repeat-containing protein 7 (FBW7) is a member of the F-box protein family that regulates cell cycle progression, and cell growth and differentiation. FBW7 also functions as a tumor suppressor. Methods: We used cell viability assays, Western blotting, and immunofluorescence combined with siRNA interference or plasmid transfection to investigate the underlying mechanism of cisplatin resistance in NSCLC cells. Results: We found that FBW7 upregulation significantly increased cisplatin chemosensitivity and that cells expressing low levels of FBW7, such as NCI-H1299 cells, have a mesenchymal phenotype. Furthermore, siRNA-mediated silencing or plasmid-mediated upregulation of FBW7 resulted in altered epithelial-mesenchymal transition (EMT) patterns in NSCLC cells. These data support a role for FBW7 in regulating the EMT in NSCLC cells. Conclusion: FBW7 is a potential drug target for combating drug resistance and regulating the EMT in NSCLC cells.