Seungkoo Lee

ERCC1 expression as a prognostic marker in N2(+) nonsmall-cell lung cancer patients treated with platinum-based neoadjuvant concurrent chemoradiotherapy.

Excision repair cross‐complementation Group 1 (ERCC1) overexpression is associated with resistance to cisplatin‐based chemotherapy in patients with nonsmall‐cell lung cancer (NSCLC). A preliminary study also suggested that ERCC1 expression is associated with radioresistance in lung cancer cells. The aim of this study was to evaluate the clinical implications of ERCC1 expression in stage IIIA N2‐positive NSCLC patients treated with platinum‐based neoadjuvant concurrent chemoradiotherapy (CCRT) followed by surgery.

Expression of Excision Repair Cross-Complementation Group 1 as Predictive Marker for Nasopharyngeal Cancer Treated With Concurrent Chemoradiotherapy

PURPOSE Cisplatin-based concurrent chemoradiotherapy is the standard treatment of nasopharyngeal cancer. The expression of excision repair cross-complementation group 1 (ERCC1) has been reported to be associated with resistance to platinum-based chemotherapy. We evaluated whether ERCC1 expression could predict the treatment response and survival outcome of patients with locally advanced nasopharyngeal cancer who were treated with cisplatin-based concurrent chemoradiotherapy. METHODS AND MATERIALS Immunohistochemistry was used to examine the expression of ERCC1 in nasopharyngeal tumor tissue. Patients were categorized into either a resistant or sensitive group depending on their treatment response outcome. A total of 77 patients were assessed in the present study. RESULTS The resistant and sensitive groups included 25 and 52 patients, respectively. ERCC1 expression was positive in the tumor tissue for 39 of the 77 patients (51%). Significantly more ERCC1-negative tumors were in the sensitive group than in the resistant group (p = .035). In terms of survival outcome, univariate analysis determined that patients with ERCC1-negative tumors had longer disease-free survival (p = .076) and overall survival (p = .013) than patients with ERCC1-positive tumors. Multivariate analysis determined that negative ERCC expression in tumors was an independent predictor for prolonged overall survival (hazard ratio, 0.14; 95% confidence interval, 0.03-0.71). CONCLUSION These results suggest that ERCC1 expression might be a useful predictive marker in patients with locally advanced nasopharyngeal cancer who are under consideration for cisplatin-based concurrent chemoradiotherapy.

RNA sequencing identifies novel markers of non-small cell lung cancer.

INTRODUCTION The development of reliable gene expression profiling technology increasingly impacts our understanding of lung cancer biology. Here, we used RNA sequencing (RNA-Seq) to compare the transcriptomes of non-small cell lung cancer (NSCLC) and normal lung tissues and to investigate expression in lung cancer tissues. METHODS We enrolled 88 male patients (mean age, 61.2 years) with NSCLC. RNA-Seq was performed on 88 pairs of NSCLC tumor tissue and non-tumor tissue from 54 patients with adenocarcinoma and 34 patients with squamous cell carcinoma. Immunohistochemistry was performed to validate differential candidate gene expression in a different NSCLC group. RESULTS RNA-Seq produced 25.41 × 10(6) (± 8.90 × 10(6)) reads in NSCLC tissues and 24.70×10(6) (± 4.70 × 10(6)) reads in normal lung tissues [mean (± standard deviation)]. Among the genes expressed in both tissues, 335 were upregulated and 728 were downregulated ≥ 2-fold (p < 0.001). Four upregulated genes - CBX3, GJB2, CRABP2, and DSP - not previously reported in lung cancer were studied further. Their altered expression was verified by immunohistochemistry in a different set of NSCLC tissues (n = 154). CBX3 was positive in 90.3% (139 cases) of the samples; GJB2, in 22.7% (35 cases); CRABP2, in 72.1% (111 cases); and DSP, in 17.5% (27 cases). The positive rate of CRABP2 was higher in adenocarcinoma than squamous cell carcinoma (p < 0.01). CONCLUSIONS CBX3 and CRABP2 expression was markedly increased in lung cancer tissues and especially CRABP2 may be promising candidate genes in lung adenocarcinoma.

Prevention of VEGF-mediated microvascular permeability by C-peptide in diabetic mice

AIMS Human C-peptide has a beneficial effect on the prevention of diabetic neuropathy, nephropathy, and vascular complications; however, its role in protection against increased vascular permeability in diabetes remains unclear. Our purpose was to explore the potential protective role of C-peptide against microvascular permeability mediated by vascular endothelial growth factor (VEGF)-induced reactive oxygen species (ROS) generation in diabetes. METHODS AND RESULTS Generation of intracellular ROS, real-time changes in intracellular Ca(2+), ROS-dependent stress fibre formation, and the disassembly of the adherens junctions were studied by a confocal microscopy in human umbilical vein endothelial cells (HUVECs). VEGF-induced vascular leakage was investigated in the skin of diabetic mice using a Miles vascular permeability assay. Microvascular leakage in the retina of streptozotocin diabetic mice was investigated using a confocal microscopy after left ventricle injection of fluorescein isothiocyanate (FITC)-dextran. C-peptide inhibited the VEGF-induced ROS generation, stress fibre formation, disassembly of vascular endothelial cadherin, and endothelial permeability in HUVECs. Intradermal injection of C-peptide prevented VEGF-induced vascular leakage. Consistent with this, intravitreal injection of C-peptide prevented the extravasation of FITC-dextran in the retinas of diabetic mice, which was also prevented by anti-VEGF antibody and ROS scavengers in diabetic mice. Conclusions/interpretation C-peptide prevents VEGF-induced microvascular permeability by inhibiting ROS-mediated intracellular events in diabetic mice, suggesting that C-peptide replacement is a promising therapeutic strategy to prevent diabetic retinopathy.

Molecular biomarkers for advanced renal cell carcinoma: Implications for prognosis and therapy

OBJECTIVE The aim of this study was to determine reliable predictive biomarkers for patients with metastatic renal cell carcinomas (RCCs) who had received cytokine therapy. METHODS Tissue specimens were obtained from 62 patients with metastatic RCCs between 1995 and 2006. Paraffin wax embedded tissues were immunostained for carbonic anhydrase IX (CAIX), cyclooxygenase-2 (COX-2), and vascular endothelial growth factor (VEGF). RESULTS Fifty-two specimens (84%) were assessed as clear cell type, with 5, 3, and 2 tumors showing sarcomatoid, papillary, and undifferentiated features, respectively. With a median 54 months of follow-up, 15/18 responding patients (83%) exhibited high CAIX staining compared with only 24/44 (55%) nonresponding patients (odds ratio, OR, 4.1; 95% confidence interval, CI 1.1-16.5, P = 0.04). There was a positive correlation between maximal COX-2 intensity and response for cytokine therapy (Spearman test P = 0.001; rho = 0.408). Corrected calcium level < or = 10 mg/dl (hazard ratio, HR, 0.1; 95% CI 0.15-0.28; P < 0.001), normal hemoglobin level (HR 0.30; 95% CI 0.15-0.50; P = 0.001), and COX-2 expression > or = 50% (HR 0.33; 95% CI 0.15-0.70; P = 0.008) were significant predictive factors of prolonged overall survival. CONCLUSIONS Thus, COX-2 and CAIX seem to be important predictors of outcome in patients with metastatic RCCs and might enhance the prognostic information obtained from pathology specimens.

Papillary adenocarcinoma arising in a duplication of the cecum

Malignant carcinomatous change is a rare complication in an enteric duplication cyst, and papillary adenocarcinoma is especially unusual. We describe a papillary adenocarcinoma, arising from a duplication of the colon, seen as a cyst with an enhancing papillary projection nodule located adjacent to the wall of the ascending colon and cecum on computed tomography.

Metabolic syndrome and sex-specific socio-economic disparities in childhood and adulthood: the Korea National Health and Nutrition Examination Surveys

To examine whether adulthood and/or childhood sex‐specific socio‐economic disparities are associated with metabolic syndrome and its components in a developed non‐Western setting.

Sirtuin 3 (SIRT3) Regulates α-Smooth Muscle Actin (α-SMA) Production through the Succinate Dehydrogenase-G Protein-coupled Receptor 91 (GPR91) Pathway in Hepatic Stellate Cells.

Sirtuin 3 (SIRT3) is an NAD+-dependent protein deacetylase. Recent studies have shown that SIRT3 expression is decreased in nonalcoholic fatty liver disease (NAFLD). Moreover, SIRT3 is a key regulator of succinate dehydrogenase (SDH), which catalyzes the oxidation of succinate to fumarate. Increased succinate concentrations and the specific G protein-coupled receptor 91 (GPR91) are involved in the activation of hepatic stellate cells (HSCs). In this study, we aimed to establish whether SIRT3 regulated the SDH activity, succinate, and GPR91 expression in HSCs and an animal model of NAFLD. Our goal was also to determine whether succinate released from hepatocytes regulated HSC activation. Inhibiting SIRT3 using SIRT3 siRNA exacerbated HSC activation via the SDH-succinate-GPR91 pathway, and SIRT3 overexpression or honokiol treatment attenuated HSC activation in vitro. In isolated liver and HSCs from methionine- and choline-deficient (MCD) diet-induced NAFLD, the expression of SIRT3 and SDH activity was decreased, and the succinate concentrations and GPR91 expression were increased. Moreover, we found that GPR91 knockdown or resveratrol treatment improved the steatosis in MCD diet-fed mice. This investigation revealed a novel mechanism of the SIRT3-SDH-GPR91 cascade in MCD diet-induced HSC activation in NAFLD. These findings highlight the biological significance of novel strategies aimed at targeting SIRT3 and GPR91 in HSCs with the goal of improving NAFLD treatment.

Human follicular dendritic cells promote germinal center B cell survival by providing prostaglandins

Evidence for the immunoregulatory function of lipid molecules in addition to proteins is accumulating. Based on our previous reports on the production of prostaglandin E₂ (PGE₂) and prostacyclin by human follicular dendritic cells (FDCs), we hypothesized that these prostaglandins (PGs) have a regulatory effect on the survival, proliferation, and differentiation of germinal center B (GC) cells. We observed that PGE₂ and a prostacyclin analog (beraprost) specifically enhanced the viable recovery of GC B cells in dose-dependent manners. FDC-like cells also mimicked the effect of PGE₂, which was significantly inhibited in the presence of indomethacin. The viable recovery was due to the prevention of cell death by PGE₂ and beraprost but did not result from augmented proliferation of GC B cells. The effect of PGE₂ and beraprost was manifest when they were added at early times of the culture. Interestingly, we found that the combined addition of a pan-caspase inhibitor and a necroptosis inhibitor gave rise to a similar result to PGE₂. Finally, PGE₂ and beraprost enhanced the generation of both CD20⁻CD38⁺ plasma cells and CD20⁺CD38⁻ memory B cells from GC B cells. Our current data suggest that FDCs play an important function of sustaining GC B cell survival by providing PGs. Our data also implies that selective cyclooxygenase inhibitors administered during infection or vaccination may have an adverse effect on the course of humoral immune response.

BIX02189 inhibits TGF-β1-induced lung cancer cell metastasis by directly targeting TGF-β type I receptor

Transforming growth factor-β1 (TGF-β1) promotes tumor metastasis by inducing an epithelial-to-mesenchymal transition (EMT) in cancer cells. In this study, we investigated the effects of BIX02189 and XMD8-92, pharmacologic inhibitors of the MEK5 [mitogen-activated protein kinase/extracellular-signal-regulated kinase (ERK)5] signaling pathway, on the EMT and migration of cancer cells induced by TGF-β1. In human A549 lung cancer cells, TGF-β1-induced EMT, cell motility, and expression of matrix metalloproteinase-2 were completely inhibited by BIX02189, but not by XMD8-92 or small interference RNAs specific to MEK5 and ERK5. Interestingly, BIX02189 strongly blocked the activation of TGF-β1 signaling components, and this inhibitory effect was not reproduced by MEK5 inhibition. Molecular docking simulation and kinase assays revealed that BIX02189 binds directly to the ATP-binding site of the TGF-β receptor type I (TβRI) and suppresses its kinase activity. Finally, the anti-metastatic effect of BIX02189 was validated in a TβRI-derived A549 xenograft mouse model. Collectively, these findings newly characterize BIX02189 as a potent inhibitor of TβRI that can block the tumor metastatic activity of TGF-β1.