Wonhee Jang

Galectin-3 supports stemness in ovarian cancer stem cells by activation of the Notch1 intracellular domain

Ovarian cancer is the most lethal gynecologic disease because usually, it is lately sensed, easily acquires chemoresistance, and has a high recurrence rate. Recent studies suggest that ovarian cancer stem cells (CSCs) are involved in these malignancies. Here, we demonstrated that galectin-3 maintains ovarian CSCs by activating the Notch1 intracellular domain (NICD1). The number and size of ovarian CSCs decreased in the absence of galectin-3, and overexpression of galectin-3 increased them. Overexpression of galectin-3 increased the resistance for cisplatin and paclitaxel-induced cell death. Silencing of galectin-3 decreased the migration and invasion of ovarian cancer cells, and overexpression of galectin-3 reversed these effects. The Notch signaling pathway was strongly activated by galectin-3 overexpression in A2780 cells. Silencing of galectin-3 reduced the levels of cleaved NICD1 and expression of the Notch target genes, Hes1 and Hey1. Overexpression of galectin-3 induced NICD1 cleavage and increased expression of Hes1 and Hey1. Moreover, overexpression of galectin-3 increased the nuclear translocation of NICD1. Interestingly, the carbohydrate recognition domain of galectin-3 interacted with NICD1. Overexpression of galectin-3 increased tumor burden in A2780 ovarian cancer xenografted mice. Increased expression of galectin-3 was detected in advanced stages, compared to stage 1 or 2 in ovarian cancer patients, suggesting that galectin-3 supports stemness of these cells. Based on these results, we suggest that targeting galectin-3 may be a potent approach for improving ovarian cancer therapy.

Electromagnetized gold nanoparticles mediate direct lineage reprogramming into induced dopamine neurons in vivo for Parkinson's disease therapy

Electromagnetic fields (EMF) are physical energy fields generated by electrically charged objects, and specific ranges of EMF can influence numerous biological processes, which include the control of cell fate and plasticity. In this study, we show that electromagnetized gold nanoparticles (AuNPs) in the presence of specific EMF conditions facilitate an efficient direct lineage reprogramming to induced dopamine neurons in vitro and in vivo. Remarkably, electromagnetic stimulation leads to a specific activation of the histone acetyltransferase Brd2, which results in histone H3K27 acetylation and a robust activation of neuron-specific genes. In vivo dopaminergic neuron reprogramming by EMF stimulation of AuNPs efficiently and non-invasively alleviated symptoms in mouse Parkinsons disease models. This study provides a proof of principle for EMF-based in vivo lineage conversion as a potentially viable and safe therapeutic strategy for the treatment of neurodegenerative disorders.

Optimized magnetic bead-based immunoassay for automated detection of protein toxins

Rapid, accurate, and autonomous analysis of bioagents in the environment is critical in protecting human health from natural and intentional environmental contamination with biological toxicants. We previously developed and tested an immunoassay protocol that can be utilized for automated and simultaneous detection of selected biological agents and toxins. We adopted an antibody-based approach for the detection of pathogens and/or toxins. The fluorescent eTags™ were used as reporter molecules and the immunoassay was modified for automated field-deployed detection of pathogens and/or toxins. The present study improved the limit of detection of this system to be suitable for the detection of environmental toxins. We tested different settings to optimize the assay protocol and successfully detected 10 ng/mL (or 100 fg) of an toxin analog, ovalbumin. The developed assay represents a notable improvement from currently available assays in terms of reduced time, increased sensitivity, and automation potential. Additionally, this assay can be easily modified, with the appropriate antibodies, to detect a wide range of proteins and infectious agents.

Meta-analysis of microarray and RNA-Seq gene expression datasets for carcinogenic risk: An assessment of Bisphenol A

Bisphenol A (BPA) is an endocrine-disrupting chemical that is related to many diseases, including heart attacks and diabetes. Recently, several studies have reported the carcinogenic potential of BPA in rodents, yet carcinogenic effects of BPA in humans remains unclear. In this study, meta-analysis was applied to independent GEO datasets, based on 158 Affymetrix microarrays and 8 Illumina RNA-Seqs. Additionally, we performed functional enrichment analysis, disease similarity analysis based on Disease Ontology (DO) analysis, and network analysis. 1,993 (1,457 up-, 536 down-regulated) differentially expressed genes (DEGs) were identified from five GEO datasets by adjusting for batch effects. Using disease similarity analysis, we demonstrated that results of DO analysis of the top 20 diseases were highly related to breast cancer. Moreover, we showed that the DEGs were significantly enriched in gene expression datasets on human breast cancer tissue via gene set enrichment analysis. By performing network analysis, we finally identified 85 (68 up- and 17 down-regulated) DEGs, and some of their expression levels were validated by quantitative PCR. The identified DEGs were regarded as genetic markers for carcinogenic risks, indicating that BPA may be a potential carcinogenic chemical contributing to the cause of breast cancer in humans.

Meta-analysis of microarray datasets for the risk assessment of coplanar polychlorinated biphenyl 77 (PCB77) on human health

Polychlorinated biphenyls (PCBs) are persistent organic compounds that have been banned since 1970s, but continue to contaminate the environment. PCBs are categorized into two structural groups: coplanar and non-coplanar PCBs. The coplanar PCBs are dioxin-like potent toxic compounds. To evaluate their effects on humans, we chose a coplanar PCB77 for data analysis. We performed meta- analysis by integrating datasets via the Rank Product method, and identified 375 up- and 66 down- regulated differentially expressed genes (DEGs). Notably, up-regulated genes were significantly associated with liver and kidney diseases. Using gene ontology enrichment, we found that the up-regulated DEGs were significantly enriched in the apoptotic process (false discovery rate, FDR=1.62e-10) and response to unfolded protein (FDR=7.65e-10). Protein-protein interaction networks identified the hub proteins containing HSP90AB1 and HSPA5. These findings suggest that our DEGs may provide a robust set of genetic markers for PCB77.

Identification of Potential Novel Biomarkers and Signaling Pathways Related to Otitis Media Induced by Diesel Exhaust Particles Using Transcriptomic Analysis in an In Vivo System

Introduction Air pollutants are associated with inflammatory diseases such as otitis media (OM). Significantly higher incidence rates of OM are reported in regions with air pollution. Diesel exhaust particles (DEPs) comprise a major class of contaminants among numerous air pollutants, and they are characterized by a carbonic mixture of polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, and small amounts of sulfate, nitrate, metals and other trace elements. DEP exposure is a risk factor for inflammatory diseases. Our previous study identified potential biomarkers using gene expression microarray and pathway analyses in an in vitro system. Although in vitro investigations have been conducted to elucidate plausible biomarkers and molecular mechanisms related to DEP exposure, in vivo studies are necessary to identify the exact biological relevance regarding the incidence of OM caused by DEP exposure. In this study, we identified potential molecular biomarkers and pathways triggered by DEP exposure in a rodent model. Methods Transcriptomic analysis was employed to identify novel potential biomarkers in the middle ear of DEP-exposed mice. Results A total of 697 genes were differentially expressed in the DEP-exposed mice; 424 genes were upregulated and 273 downregulated. In addition, signaling pathways among the differentially expressed genes mediated by DEP exposure were predicted. Several key molecular biomarkers were identified including cholinergic receptor muscarinic 1 (CHRM1), erythropoietin (EPO), son of sevenless homolog 1 (SOS1), estrogen receptor 1 (ESR1), cluster of differentiation 4 (CD4) and interferon alpha-1 (IFNA1). Conclusions Our results shed light on the related cell processes and gene signaling pathways affected by DEP exposure. The identified biomarkers might be potential candidates for determining early diagnoses and effective treatment strategies for DEP-mediated disorders.

Intein-mediated protein engineering for biosensor fabrication

Intein-mediated protein engineering has become a valuable tool for biosensing applications. Expressed protein ligation and protein trans-splicing were used to generate proteins with necessary tags or cyclic peptides that can be used to build various biosensing platforms such as biochips or sensor proteins. Especially the use of split-inteins that carry out conditional protein splicing reaction enabled the fabrication of various genetically-encoded biosensors that can monitor various signaling events in vivo including protein- protein interactions and protein translocalization. Biological targets activated split-inteins to generate functioning reporter molecules, such as luciferase and autofluorescent proteins. We here review various sensing platforms that utilize intein-mediated protein engineering technology mainly focusing on cell-based biosensors.

Biomedical applications and safety issues of gold nanoparticles

Recently, nanoparticles (NPs) are introduced to a broad range of biomedical applications including drug delivery, imaging, and sensors. With increased use of NPs and the emergence of consumer products containing NPs, there are growing concerns for the safety of NPs. Among many different types of NPs, gold nanoparticles (GNPs) are popular materials for various biomedical applications. GNPs can be fabricated in various forms using different concentrations of growth-directing surfactant. In this mini-review, we summarize the recent advancements made in the field of safety and biomedical applications of GNPs, and show that GNPs can also be applied in the ablation of thyroid cancer remnants after surgery

Inhibitory Effects of Novel SphK2 Inhibitors on Migration of Cancer Cells

BACKGROUND Cell migration is an essential process for survival and differentiation of mammalian cells. Numerous diseases are induced or influenced by inappropriate regulation of cell migration, which plays a key role in cancer cell metastasis. In fact, very few anti-metastasis drugs are available on the market. SphKs are enzymes that convert sphingosine to sphingosine-1-phosphate (S1P) and are known to control various cellular functions, including migration of cells. In human, SphK2 is known to promote apoptosis, suppresses cell growth, and controls cell migration; in addition, the specific ablation of SphK2 activity was reported to inhibit cancer cell metastasis. OBJECTIVE The previously identified SG12 and SG14 are synthetic analogs of sphingoid and can specifically inhibit the functions of SphK2. We investigated the effects of the SphK2 specific inhibitors on the migratory behavior of cells. METHOD We investigated how SG12 and SG14 affect cell migration by monitoring both cumulative and individual cell migration behavior using HeLa cells. RESULTS SG12 and SG14 mutually showed stronger inhibitory effects with less cytotoxicity compared with a general SphK inhibitor, N,N-dimethylsphingosine (DMS). The mechanistic aspects of specific SphK2 inhibition were studied by examining actin filamentation and the expression levels of motility-related genes. CONCLUSION The data revealed that SG12 and SG14 resemble DMS in decreasing overall cell motility, but differ in that they differentially affect motility parameters and motility-related signal transduction pathways and therefore actin polymerization, which are not altered by DMS. Our findings show that SphK2 inhibitors are putative candidates for anti-metastatic drugs.

Application of biosensors in smart packaging

Smart packaging is an exponentially growing field in the food industry, encompassing various fields of technology to aid in controlling the environment and detecting changes in the headspace, and tracing product history. Due to the frequent incidents of foodborne illnesses around the world, the major issues presently facing the industry involve ensuring the quality and the safety of its food products. Smart packaging, with built-in sensors and indicators, has been touted as a convenient technology to monitor freshness. In this review, we focus on current applications of sensors and/or indicators that can detect the freshness of meat products in smart packaging, since the mechanisms of spoilage are fundamentally similar in all types of meats. The prerequisites and principles of different types of currently available indicators/sensors for smart packaging are addressed, and an approach to improve the current technology is discussed.