• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2008.04a
• /
• pp.77-86
• /
• 2008

It's been known that overexpression of the oncoprotein Her2 (eu/ErbB2), transmembrane receptor protein, occurs in human breast cancer. Her2-positive breast cancer patients who have Her2 overexpression show less therapeutic efficacy with enhanced metathesis and increased resistance to chemotherapy. So far, a humanized monoclonal antibody against Her2 protein called Herceptin is the only drug approved by Food and Drug Administration for treatment of Her2-overexpressing breast tumors. However, antibody therapy of Herceptin may not be ideal method for therapeutic intervention of Her2 protein expression. The therapeutic intervention of Her2 protein expression may be more efficiently achieved by inhibiting the expression of Her2 gene rather than by down-regulating the Her2 protein already overexpressed. Here, we found that the interaction of two proteins of ESX (an epithelial-restricted transcription factor) and DRIP130/CRSP130/Sur2 (a Ras-linked subunit of human mediator complexes) mediates the expression of Her2 gene. The association of ESX with Sur2 is mediated by a small hydrophobic face of 8-amino acid helix in ESX, suggesting that the ESX-Sur2 interaction can be a new novel target for Her2-positive cancer. The process to develop potent ESX-Sur2 interaction inhibitors targeting for Her2-positive cancer therapeutics will be discussed.

• YAKHAK HOEJI
• /
• v.55 no.1
• /
• pp.75-79
• /
• 2011

The replication competent adenoviral vector (AV), AdLPCDIRESE1A was generated and reported previously to have cytotoxic effects in some cell lines. In AdLPCDIRESE1A, the expression of cytosine deaminse (CD) and E1A genes are under the control of tumor-specific L-plastin promoter. CD enzyme can deaminate the nontoxic prodrug 5-fluorocytosine (5-FC) to the toxic 5-fluorouracil (5-FU). E1A gene is essential for viral replication. Primary liver cancer, most of which is hepatocellular carcinoma (HCC), is the third common leading cancer in Korea. Thus, we have conducted in vitro preclinical study to evaluate effectiveness of AdLPCDIRESE1A on HCC. The efficacy of cytotoxicity was measured by generation of cytopathic effect (CPE) and cell counting. We infected HepG2 cells with various MOI of vector alone or concurrent with 5-FC. Exposure of cells to AdLPCDIRESE1A generated a significant cytotoxic effect as compared to the control. Almost 83% of the cell had manifested the characteristic cytotoxic effect on day 9 after infection of cells with 10 MOI of vector. We also observed the additive cytotoxic effects when AdLPCDIRESE1A vector had been coadministrated with 5-FC. The results suggest that the use of AdLPCDIRESE1A/5FC may be value in treatment of liver cancer. Further animal studies are needed for clinical trial.

• Molecules and Cells
• /
• v.45 no.9
• /
• pp.622-630
• /
• 2022

Colorectal cancer (CRC) has a high mortality rate among cancers worldwide. To reduce this mortality rate, chemotherapy (5-fluorouracil, oxaliplatin, and irinotecan) or targeted therapy (bevacizumab, cetuximab, and panitumumab) has been used to treat CRC. However, due to various side effects and poor responses to CRC treatment, novel therapeutic targets for drug development are needed. In this study, we identified the overexpression of EHMT1 in CRC using RNA sequencing (RNA-seq) data derived from TCGA, and we observed that knocking down EHMT1 expression suppressed cell growth by inducing cell apoptosis in CRC cell lines. In Gene Ontology (GO) term analysis using RNA-seq data, apoptosis-related terms were enriched after EHMT1 knockdown. Moreover, we identified the CHOP gene as a direct target of EHMT1 using a ChIP (chromatin immunoprecipitation) assay with an anti-histone 3 lysine 9 dimethylation (H3K9me2) antibody. Finally, after cotransfection with siEHMT1 and siCHOP, we again confirmed that CHOP-mediated cell apoptosis was induced by EHMT1 knockdown. Our findings reveal that EHMT1 plays a key role in regulating CRC cell apoptosis, suggesting that EHMT1 may be a therapeutic target for the development of cancer inhibitors.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.11
• /
• pp.4499-4505
• /
• 2014

Glioblastoma, the most aggressive and malignant form of glioma, appears to be resistant to various chemotherapeutic agents. Hence, approaches have been intensively investigated to targeti specific molecular pathways involved in glioblastoma development and progression. Aloe emodin is believed to modulate the expression of several genes in cancer cells. We aimed to understand the molecular mechanisms underlying the therapeutic effect of Aloe emodin on gene expression profiles in the human U87 glioblastoma cell line utilizing microarray technology. The gene expression analysis revealed that a total of 8,226 gene alterations out of 28,869 genes were detected after treatment with $58.6{\mu}g/ml$ for 24 hours. Out of this total, 34 genes demonstrated statistically significant change (p<0.05) ranging from 1.07 to 1.87 fold. The results revealed that 22 genes were up-regulated and 12 genes were down-regulated in response to Aloe emodin treatment. These genes were then grouped into several clusters based on their biological functions, revealing induction of expression of genes involved in apoptosis (programmed cell death) and tissue remodelling in U87 cells (p<0.01). Several genes with significant changes of the expression level e.g. SHARPIN, BCAP31, FIS1, RAC1 and TGM2 from the apoptotic cluster were confirmed by quantitative real-time PCR (qRT-PCR). These results could serve as guidance for further studies in order to discover molecular targets for the cancer therapy based on Aloe emodin treatment.

• Molecular & Cellular Toxicology
• /
• v.3 no.4
• /
• pp.320-325
• /
• 2007

Promoter hypermethylation of the $p16^{INK4a}$ gene was investigated in 52 sets of samples of tumor tissue and adjacent normal tissue from Korean patients with colorectal cancer, using the proposed modified the Real-time PCR/SYBR Green detection method presented in this study. In normal tissue, 29 of 52 patients (56%) were methylated and in tumor tissue, 23 of 52 patients (44%) were methylated. The 34 cases (65.4%) showed a concordant DNA methylation pattern in both normal tissue and tumor tissue. Analyzing the association between the clinicopathologic features and DNA methylation status of the $p16^{INK4a}$ gene, the DNA methylation status according to by Duke's stage was different while other clinicopathological characteristics, including the age, sex, tumor stage, and histologic type of the patient were not found to be correlated with $p16^{INK4a}$ methylation. With multivariate logistic regression, it was observed that the DNA methylation status of $p16^{INK4a}$ gene in normal tissue was correlated with the DNA methylation status of the $p16^{INK4a}$ gene in tumor tissue (P=0.026). According to a Kaplan-Meier survival analysis, a difference in the survival rate by DNA methylation status was found, but it was not significant.

• Biomolecules & Therapeutics
• /
• v.17 no.2
• /
• pp.138-143
• /
• 2009

We have reported previously on a replication incompetent recombinant adenoviral vector, AdLPCD, in which the expression of cytosine deaminase gene (CD) is driven by the tumor-specific L-plastin promoter. AdLPCD vector had been evaluated for its efficacy of chemosensitization of ovarian cancer cells to 5-FC. In spite of the fact that ovarian cancer cells, i.e., OVCAR-3 and SK-OV-3, are capable for adenoviral transduction judged by LacZ reporter gene analysis, two cell lines demonstrated quite different sensitivities toward AdLPCD/5-FC system. In OVCAR-3 cells, infection of AdLPCD followed by exposure to 5-FC resulted in the suppression of cell growth with statistical significance. On the other hand, SK-OV-3 cells were more resistant to the CD/5-FC strategy compared with OVCAR-3 cells under the same condition. The object of study was to investigate factors that would determine the sensitivity to AdLPCD/5-FC. We evaluated conversion rate of 5-FC to 5-FU after infection of AdLPCD by HPLC analysis, $IC_{50}$ of 5-FU, the expression level of integrin receptors i.e., ${\alpha}v{\beta}3$ and ${\alpha}v{\beta}5$, and status of p53 in OVCAR-3 and SK-OV-3 cells. The results indicated that OVCAR-3 cells have few favorable features compared with SK-OV-3 cells to be more effective to the AdLPCD/5-FC strategy; higher level of ${\alpha}v{\beta}5$ integrin, higher rate of conversion of 5-FC into 5-FC, and lower $IC_{50}$ of 5-FU. The results suggest that the replacement of 5-FU with CD/5-FC in combination chemotherapy would be less toxic and much greater cytotoxicity than the conventional combination chemotherapy in some patients.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.11
• /
• pp.6681-6686
• /
• 2013

Background: Fatal adverse events (FAEs) have been reported with sorafenib, a vascular endothelial growth factor receptor kinase inhibitor (VEGFR TKI). We here performed an up-to-date and detailed meta-analysis to determine the overall risk of FAEs associated with sorafenib. Methods: Databases, including PubMed, Embase and Web of Science, and abstracts presented at the American Society of Clinical Oncology annual meetings were searched to identify relevant studies. Eligible studies included randomized controlled trials evaluating sorafenib effects in patients with all malignancies. Summary incidence rates, relative risks (RRs), and 95% confidence intervals (CIs) were calculated for FAEs. In addition, subgroup analyses were performed according to tumor type and therapy regimen. Results: 13 trials recruiting 5,546 patients were included in our analysis. The overall incidence of FAEs with sorafenib was 1.99% (95%CI, 0.98-4.02%). Patients treated with sorafenib had a significantly increased risk of FAEs compared with patients treated with control medication, with an RR of 1.77 (95%CI 1.25-2.52, P=0.001). Risk varied with tumour type, but appeared independent of therapy regimen. A significantly increased risk of FAEs was observed in patients with lung cancer (RR 2.26; 95% CI 1.03-4.99; P= 0.043) and renal cancer (RR 1.84; 95% CI 1.15-2.94; P= 0.011). The most common causes of FAEs were hemorrhage (8.6%) and thrombus or embolism (4.9%). Conclusions: It is important for health care practitioners to be aware of the risks of FAEs associated with sorafenib, especially in patients with renal and lung cancer.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.9
• /
• pp.4943-4952
• /
• 2013

Hepatocellular carcinoma (HCC) is one of the most common malignancies, with a very poor prognosis. Despite significant improvements in diagnosis and treatment in recent years, the long-term therapeutic efficacy is poor, partially due to tumor metastasis, tecurrence, and resistance to chemo-or radio-therapy. Recently, it was found that a major feature of tumors is a combination of unrestrained cell proliferation and impaired apoptosis. There are now 8 recogized members of the IAP-family: NAIP, c-IAP1, c-IAP2, XIAP, Survivin, Bruce, Livin and ILP-2. There proteins all contribute to ingibition of apoptosis, and provide new potential avenues of cancer treatment. As a powerful tool to suppress gene expression in mammalian cells, RNAi species for inhibiting IAP genes cab be directed against cancers. This review will provide a brief introduction to recent developments of the application IAP-siRNA in tumor studies, with the aim of inspiring future treatment of HCC.

• Korean Journal of Head & Neck Oncology
• /
• v.37 no.2
• /
• pp.1-9
• /
• 2021

Thyroid cancer refers to various cancers arising from thyroid gland. Differentiated thyroid cancers (DTCs) include papillary, follicular, and Hurthle cell carcinomas and represent cancers retain normal thyroid functions such as iodine uptake. Radioactive iodine (RAI) is generally used for upfront treatment of metastatic DTCs, but RAI refractory DTCs remain to be clinical challenges. Sorafenib and lenvatinib were approved for the treatment of RAI refractory DTCs and more recently, genomics-based targeted therapies have been developed for NTRK and RET gene fusion-positive DTCs. Poorly differentiated and anaplastic thyroid cancers (ATCs) are extremely challenging diseases with aggressive courses. BRAF/MEK inhibition has been proven to be highly effective in BRAF V600E mutation-positive ATCs and immune checkpoint inhibitors have shown promising activities. Medullary thyroid cancers, which arise from parafollicular cells of thyroid, represent a unique subset of thyroid cancer and mainly driven by RET mutation. In addition to vandetanib and cabozantinib, highly specific RET inhibitors such as selpercatinib and pralsetinib have demonstrated impressive activity and are in clinical use.

• Journal of Yeungnam Medical Science
• /
• v.39 no.1
• /
• pp.62-66
• /
• 2022

Immune checkpoint inhibitor (ICI)-associated adrenal insufficiency is rare but may become a serious adverse event in patients treated with ICIs. The present case report documents two cases of adrenal insufficiency developed during chemotherapy plus tislelizumab (百泽安, Baize'an; BeiGene Ltd.) therapy in patients with advanced gastric cancer. Adrenal insufficiency developed after 6 and 13 cycles of treatment and was well controlled with hydrocortisone. The patients also developed hypothyroidism, which was managed with levothyroxine. Two patients showed a partial response, and one patient out of two achieved a near-complete response, sustaining over 11 months. Increased awareness of ICI-related adrenal insufficiency is crucial for early detection and prompt management of patients treated with ICIs.