Boram Choi

MicroRNA-29c mediates initiation of gastric carcinogenesis by directly targeting ITGB1

Objective Gastric cancer (GC) remains difficult to cure due to heterogeneity in a clinical challenge and the molecular mechanisms underlying this disease are complex and not completely understood. Accumulating evidence suggests that microRNAs (miRNAs) play an important role in GC, but the role of specific miRNAs involved in this disease remains elusive. We performed next generation sequencing (NGS)-based whole-transcriptome profiling to discover GC-specific miRNAs, followed by functional validation of results. Design NGS-based miRNA profiles were generated in matched pairs of GCs and adjacent normal mucosa (NM). Quantitative RT-PCR validation of miR-29c expression was performed in 274 gastric tissues, which included two cohorts of matched GC and NM specimens. Functional validation of miR-29c and its gene targets was undertaken in cell lines, as well as K19-C2mE and K19-Wnt1/C2mE transgenic mice. Results NGS analysis revealed four GC-specific miRNAs. Among these, miR-29c expression was significantly decreased in GC versus NM tissues (p<0.001). Ectopic expression of miR-29c mimics in GC cell lines resulted in reduced proliferation, adhesion, invasion and migration. High miR-29c expression suppressed xenograft tumour growth in nude mice. Direct interaction between miR-29c and its newly discovered target, ITGB1, was identified in cell lines and transgenic mice. MiR-29c expression demonstrated a stepwise decrease in wild type hyperplasia-dysplasia cascade in transgenic mice models of GC. Conclusions MiR-29c acts as a tumour suppressor in GC by directly targeting ITGB1. Loss of miR-29c expression is an early event in the initiation of gastric carcinogenesis and may serve as a diagnostic and therapeutic biomarker for patients with GC.

Genomic alterations in BCL2L1 and DLC1 contribute to drug sensitivity in gastric cancer

Significance Gastric cancer (GC) is one of the major causes of cancer-related deaths worldwide, but targeted therapy for GC is limited. Here, we identified two druggable targets from genomic alteration profiling of 103 patients with GC from Asia and validated the target suitability using patient-derived GC xenograft models, which recapitulate the tumor biology observed in patients. Combination therapy of irinotecan (standard treatment) with a BCL2L1 (BCL2-like 1)-targeted drug was effective in size reduction of GC tumors having amplification of the BCL2L1 gene, and genomic mutations of deleted in liver cancer 1 (DLC1) were associated with increased sensitivity to a ROCK inhibitor. Therefore, our study strongly suggests that BCL2L1 and DLC1 can serve as targets for novel GC therapies. Gastric cancer (GC) is the third leading cause of cancer-related deaths worldwide. Recent high-throughput analyses of genomic alterations revealed several driver genes and altered pathways in GC. However, therapeutic applications from genomic data are limited, largely as a result of the lack of druggable molecular targets and preclinical models for drug selection. To identify new therapeutic targets for GC, we performed array comparative genomic hybridization (aCGH) of DNA from 103 patients with GC for copy number alteration (CNA) analysis, and whole-exome sequencing from 55 GCs from the same patients for mutation profiling. Pathway analysis showed recurrent alterations in the Wnt signaling [APC, CTNNB1, and DLC1 (deleted in liver cancer 1)], ErbB signaling (ERBB2, PIK3CA, and KRAS), and p53 signaling/apoptosis [TP53 and BCL2L1 (BCL2-like 1)] pathways. In 18.4% of GC cases (19/103), amplification of the antiapoptotic gene BCL2L1 was observed, and subsequently a BCL2L1 inhibitor was shown to markedly decrease cell viability in BCL2L1-amplified cell lines and in similarly altered patient-derived GC xenografts, especially when combined with other chemotherapeutic agents. In 10.9% of cases (6/55), mutations in DLC1 were found and were also shown to confer a growth advantage for these cells via activation of Rho-ROCK signaling, rendering these cells more susceptible to a ROCK inhibitor. Taken together, our study implicates BCL2L1 and DLC1 as potential druggable targets for specific subsets of GC cases.

Overexpression of Plasminogen Activator Inhibitor-1 in Advanced Gastric Cancer with Aggressive Lymph Node Metastasis

Purpose The purpose of this study is to investigate differentially expressed genes using DNA microarray between advanced gastric cancer (AGC) with aggressive lymph node (LN) metastasis and that with a more advanced tumor stage but without LN metastasis. Materials and Methods Five sample pairs of gastric cancer tissue and normal gastric mucosa were taken from three patients with T3N3 stage (highN) and two with T4N0 stage (lowN). Data from triplicate DNA microarray experiments were analyzed, and candidate genes were identified using a volcano plot that showed ≥ 2-fold differential expression and were significant by Welchs t test (p < 0.05) between highN and lowN. Those selected genes were validated independently by reverse-transcriptase–polymerase chain reaction (RT-PCR) using five AGC patients, and tissue-microarray (TMA) comprising 47 AGC patients. Results CFTR, LAMC2, SERPINE2, F2R, MMP7, FN1, TIMP1, plasminogen activator inhibitor-1 (PAI-1), ITGB8, SDS, and TMPRSS4 were commonly up-regulated over 2-fold in highN. REG3A, CD24, ITLN1, and WBP5 were commonly down-regulated over 2-fold in lowN. Among these genes, overexpression of PAI-1 was validated by RT-PCR, and TMA showed 16.7% (7/42) PAI-1 expression in T3N3, but none (0/5) in T4N0 (p=0.393). Conclusion DNA microarray analysis and validation by RT-PCR and TMA showed that overexpression of PAI-1 is related to aggressive LN metastasis in AGC.

Hard and soft tissue changes of osteomyelitis of the jaws on CT images

OBJECTIVESnThis study aimed to assess the hard and soft tissue changes in osteomyelitis (OM) of the jaws using CT images.nnnSTUDY DESIGNnThe CT images of 153 patients (59 males and 94 females) with OM of the jaws were retrospectively reviewed. The relationships between each space involvement, between space and muscle involvements, between cortical bone defect and space involvement, and between cortical bone defect and muscle involvement were evaluated.nnnRESULTSnThe cortical bone defect was more common on the buccal side in the maxilla and on the lingual side in the mandible. The most commonly involved muscle was the buccinator muscle in the maxilla and the masseter muscle in the mandible and the most frequently involved space was the buccal space followed by the masticator space.nnnCONCLUSIONSnCT is a useful tool in evaluating both hard and soft tissue changes of OM of the jaws.

Severe calcified stylohyoid complex in twins: a case report

The styloid process is a cylindrical, long cartilaginous bone located on the temporal bone. The calcified stylohyoid ligament and elongated styloid process can be identified radiographically, and they are associated with a number of syndromes and symptoms. The exact cause of the styloid process elongation due to calcification and subsequent ossification of ligament is unclear. This report presents a case of severely calcified stylohyoid ligament complex occurred in twins who have the same pattern of calcification.

Reference line-pair values of panoramic radiographs using an arch-form phantom stand to assess clinical image quality

Purpose This study was performed to suggest reference line-pair values of panoramic images with clinically desirable qualities using an arch-form phantom stand. Materials and Methods The line-pair test phantom was chosen. A real skull model was selected for setting the arch-form model of the phantom stand. The phantom stand had slits in four regions (incisor, premolar, molar, TMJ). Four raw images of the test phantom in each region and one raw image of the real skull were converted into 50 test phantom images and 50 skull phantom images with various line-pair values. 50 post-processed real skull phantom images were divided into 4 groups and were randomly submitted to 14 evaluators. Image quality was graded on a 4 point scale (1. good, 2. normal, 3. poor but interpretable, and 4. not interpretable). The reference line pair was determined as the first line-pair value scored less than 2 points. Result The mean scores tended to decrease as the line-pair values increased. The reference line-pair values were 3.19 LP/mm in the incisor, 2.32 LP/mm in the premolar and TMJ, and 1.88 LP/mm in the molar region. Conclusion Image quality evaluation methods and criteria should be able to assess various regions considering the characteristics of panoramic systems. This study suggested overall and regional reference line-pair values and established a set of standard values for them.

MAL and TMEM220 are novel DNA methylation markers in human gastric cancer

Abstract Context: Gastric cancer (GC) is the fourth most common cause of cancer-related deaths worldwide. Objective: To determine the mRNA-expression of the MAL, TMEM220, MMP28, IL-19 and HOPX genes and analyse the methylation statuses of MAL and TMEM220. Materials and methods: Gene-expression levels were analysed in 10 GC cell lines and 30 matched pairs of GC and normal mucosa (NM) gastric tissue specimens in real-time reverse-transcriptase polymerase chain reactions. Gene methylation was evaluated by bisulphite sequencing. Detailed gene-methylation patterns were confirmed by pyrosequencing analysis. Results: MAL, TMEM220, MMP28 and IL-19 were significantly down-regulated in GC cell lines and GC tissues compared to NM tissues. MAL and TMEM220 were highly methylated in GC tissues, and methylation inversely correlated with expression. MAL and TMEM220 expression were restored by treatment with 5-aza-2′-deoxycytidine. MAL and TMEM220 were specifically methylated and were down-regulated in human GC. Discussion and conclusion: These loci may serve as novel methylation markers for patients with GC.

Ultrasonically Activated Shears Reduce Blood Loss without Increasing Inflammatory Reactions in Open Distal Gastrectomy for Cancer: A Randomized Controlled Study

BackgroundPrevious studies regarding ultrasonically activated shears (UAS) were performed without controlled surgical procedures or consideration of potential thermal injury due to high temperature of active blade of UAS. The purpose of this study was to evaluate the efficacy and safety of UAS through a comparison with conventional monopolar electrocautery (CME) in open distal gastrectomy for gastric cancer.MethodsFrom October 2011 to November 2012, 56 gastric cancer patients eligible for open distal gastrectomy were randomized into UAS or CME groups. Primary endpoints were estimated blood loss (EBL) during surgery and amount of drainage through the fifth postoperative day. Secondary endpoints were operation time, length of hospital stay, postoperative morbidity, changes in cytokine levels in serum, peritoneal irrigation saline, and peritoneal drainage, and inflammatory markers of serum. (Registration-number of ClinicalTrials.gov: NCT01971775).ResultsEBL was lower in the UAS group than that in the CME group (339.8xa0±xa0201.2 vs. 428.6xa0±xa0165.8xa0mL, pxa0=xa00.021). However, the amount of postoperative drainage was not significantly different between the two groups. Although the complication rate was not different between the two groups, there were three cases of intra-abdominal bleeding requiring transfusion only in the CME group. Inflammatory markers from the cytokine assays and serum laboratory tests showed no significant differences between the two groups.ConclusionsUAS reduced EBL without increasing inflammatory reactions.

Molecular dissection of distinct symptoms induced by tomato chlorosis virus and tomato yellow leaf curl virus based on comparative transcriptome analysis

The viral infection of plants may cause various physiological symptoms associated with the reprogramming of plant gene expression. However, the molecular mechanisms and associated genes underlying disease symptom development in plants infected with viruses are largely unknown. In this study, we employed RNA sequencing for in-depth molecular characterization of the transcriptional changes associated with the development of distinct symptoms induced by tomato chlorosis virus (ToCV) and tomato yellow leaf curl virus (TYLCV) in tomato. Comparative analysis of differentially expressed genes revealed that ToCV and TYLCV induced distinct transcriptional changes in tomato and resulted in the identification of important genes responsible for the development of symptoms of ToCV (i.e., chlorosis and anthocyanin accumulation) and TYLCV (i.e., yellowing, stunted growth, and leaf curl). Our comprehensive transcriptome analysis can provide molecular strategies to reduce the severity of disease symptoms as well as new insights for the development of virus-resistant crops.

Detection of Gastric Cancer with Novel Methylated DNA Markers: Discovery, Tissue Validation, and Pilot Testing in Plasma

Purpose: Gastric adenocarcinoma is the third most common cause of cancer mortality worldwide. Accurate and affordable noninvasive detection methods have potential value for screening and surveillance. Herein, we identify novel methylated DNA markers (MDM) for gastric adenocarcinoma, validate their discrimination for gastric adenocarcinoma in tissues from geographically separate cohorts, explore marker acquisition through the oncogenic cascade, and describe distributions of candidate MDMs in plasma from gastric adenocarcinoma cases and normal controls. Experimental Design: Following discovery by unbiased whole-methylome sequencing, candidate MDMs were validated by blinded methylation-specific PCR in archival case–control tissues from U.S. and South Korean patients. Top MDMs were then assayed by an analytically sensitive method (quantitative real-time allele-specific target and signal amplification) in a blinded pilot study on archival plasma from gastric adenocarcinoma cases and normal controls. Results: Whole-methylome discovery yielded novel and highly discriminant candidate MDMs. In tissue, a panel of candidate MDMs detected gastric adenocarcinoma in 92% to 100% of U.S. and South Korean cohorts at 100% specificity. Levels of most MDMs increased progressively from normal mucosa through metaplasia, adenoma, and gastric adenocarcinoma with variation in points of greatest marker acquisition. In plasma, a 3-marker panel (ELMO1, ZNF569, C13orf18) detected 86% (95% CI, 71–95) of gastric adenocarcinomas at 95% specificity. Conclusions: Novel MDMs appear to accurately discriminate gastric adenocarcinoma from normal controls in both tissue and plasma. The point of aberrant methylation during oncogenesis varies by MDM, which may have relevance to marker selection in clinical applications. Further exploration of these MDMs for gastric adenocarcinoma screening and surveillance is warranted. Clin Cancer Res; 24(22); 5724–34. ©2018 AACR.