1.Role of HIF-1α in the Responses of Tumors to Radiotherapy and Chemotherapy
Chang W SONG ; Hyunkyung KIM ; Mi-Sook KIM ; Heon J PARK ; Sun-Ha PAEK ; Stephanie TEREZAKIS ; L Chinsoo CHO
Cancer Research and Treatment 2025;57(1):1-10
Tumor microenvironment is intrinsically hypoxic with abundant hypoxia-inducible factors-1α (HIF-1α), a primary regulator of the cellular response to hypoxia and various stresses imposed on the tumor cells. HIF-1α increases radioresistance and chemoresistance by reducing DNA damage, increasing repair of DNA damage, enhancing glycolysis that increases antioxidant capacity of tumors cells, and promoting angiogenesis. In addition, HIF-1α markedly enhances drug efflux, leading to multidrug resistance. Radiotherapy and certain chemotherapy drugs evoke profound anti-tumor immunity by inducing immunologic cell death that release tumor-associated antigens together with numerous pro-immunological factors, leading to priming of cytotoxic CD8+ T cells and enhancing the cytotoxicity of macrophages and natural killer cells. Radiotherapy and chemotherapy of tumors significantly increase HIF-1α activity in tumor cells. Unfortunately, HIF-1α effectively promotes various immune suppressive pathways including secretion of immune suppressive cytokines, activation of myeloid-derived suppressor cells, activation of regulatory T cells, inhibition of T cells priming and activity, and upregulation of immune checkpoints. Consequently, the anti-tumor immunity elevated by radiotherapy and chemotherapy is counterbalanced or masked by the potent immune suppression promoted by HIF-1α. Effective inhibition of HIF-1α may significantly increase the efficacy of radiotherapy and chemotherapy by increasing radiosensitivity and chemosensitivity of tumor cells and also by upregulating anti-tumor immunity.
2.Role of HIF-1α in the Responses of Tumors to Radiotherapy and Chemotherapy
Chang W SONG ; Hyunkyung KIM ; Mi-Sook KIM ; Heon J PARK ; Sun-Ha PAEK ; Stephanie TEREZAKIS ; L Chinsoo CHO
Cancer Research and Treatment 2025;57(1):1-10
Tumor microenvironment is intrinsically hypoxic with abundant hypoxia-inducible factors-1α (HIF-1α), a primary regulator of the cellular response to hypoxia and various stresses imposed on the tumor cells. HIF-1α increases radioresistance and chemoresistance by reducing DNA damage, increasing repair of DNA damage, enhancing glycolysis that increases antioxidant capacity of tumors cells, and promoting angiogenesis. In addition, HIF-1α markedly enhances drug efflux, leading to multidrug resistance. Radiotherapy and certain chemotherapy drugs evoke profound anti-tumor immunity by inducing immunologic cell death that release tumor-associated antigens together with numerous pro-immunological factors, leading to priming of cytotoxic CD8+ T cells and enhancing the cytotoxicity of macrophages and natural killer cells. Radiotherapy and chemotherapy of tumors significantly increase HIF-1α activity in tumor cells. Unfortunately, HIF-1α effectively promotes various immune suppressive pathways including secretion of immune suppressive cytokines, activation of myeloid-derived suppressor cells, activation of regulatory T cells, inhibition of T cells priming and activity, and upregulation of immune checkpoints. Consequently, the anti-tumor immunity elevated by radiotherapy and chemotherapy is counterbalanced or masked by the potent immune suppression promoted by HIF-1α. Effective inhibition of HIF-1α may significantly increase the efficacy of radiotherapy and chemotherapy by increasing radiosensitivity and chemosensitivity of tumor cells and also by upregulating anti-tumor immunity.
3.Role of HIF-1α in the Responses of Tumors to Radiotherapy and Chemotherapy
Chang W SONG ; Hyunkyung KIM ; Mi-Sook KIM ; Heon J PARK ; Sun-Ha PAEK ; Stephanie TEREZAKIS ; L Chinsoo CHO
Cancer Research and Treatment 2025;57(1):1-10
Tumor microenvironment is intrinsically hypoxic with abundant hypoxia-inducible factors-1α (HIF-1α), a primary regulator of the cellular response to hypoxia and various stresses imposed on the tumor cells. HIF-1α increases radioresistance and chemoresistance by reducing DNA damage, increasing repair of DNA damage, enhancing glycolysis that increases antioxidant capacity of tumors cells, and promoting angiogenesis. In addition, HIF-1α markedly enhances drug efflux, leading to multidrug resistance. Radiotherapy and certain chemotherapy drugs evoke profound anti-tumor immunity by inducing immunologic cell death that release tumor-associated antigens together with numerous pro-immunological factors, leading to priming of cytotoxic CD8+ T cells and enhancing the cytotoxicity of macrophages and natural killer cells. Radiotherapy and chemotherapy of tumors significantly increase HIF-1α activity in tumor cells. Unfortunately, HIF-1α effectively promotes various immune suppressive pathways including secretion of immune suppressive cytokines, activation of myeloid-derived suppressor cells, activation of regulatory T cells, inhibition of T cells priming and activity, and upregulation of immune checkpoints. Consequently, the anti-tumor immunity elevated by radiotherapy and chemotherapy is counterbalanced or masked by the potent immune suppression promoted by HIF-1α. Effective inhibition of HIF-1α may significantly increase the efficacy of radiotherapy and chemotherapy by increasing radiosensitivity and chemosensitivity of tumor cells and also by upregulating anti-tumor immunity.
4.Reelin and APP Cooperatively Modulate Dendritic Spine Formation In Vitro and In Vivo
Hyun-ju LEE ; Jin-Hee PARK ; Justin H. TROTTER ; James N. MAHER ; Kathleen E. KEENOY ; You Mi JANG ; Youngeun LEE ; Jae-Ick KIM ; Edwin J. WEEBER ; Hyang-Sook HOE
Experimental Neurobiology 2023;32(1):42-55
Amyloid precursor protein (APP) plays an important role in the pathogenesis of Alzheimer’s disease (AD), but the normal function of APP at synapses is poorly understood. We and others have found that APP interacts with Reelin and that each protein is individually important for dendritic spine formation, which is associated with learning and memory, in vitro. However, whether Reelin acts through APP to modulate dendritic spine formation or synaptic function remains unknown. In the present study, we found that Reelin treatment significantly increased dendritic spine density and PSD-95 puncta number in primary hippocampal neurons. An examination of the molecular mechanisms by which Reelin regulates dendritic spinogenesis revealed that Reelin enhanced hippocampal dendritic spine formation in a Ras/ERK/CREB signaling-dependent manner. Interestingly, Reelin did not increase dendritic spine number in primary hippocampal neurons when APP expression was reduced or in vivo in APP knockout (KO) mice. Taken together, our data are the first to demonstrate that Reelin acts cooperatively with APP to modulate dendritic spine formation and suggest that normal APP function is critical for Reelin-mediated dendritic spinogenesis at synapses.
5.Satisfaction Survey of Telemedicine Services for the Patients With Dementia in the Vulnerable Area for Medical Service
So-Myung KIM ; Jin Hyeong J JHOO ; Gihwan BYEON ; Seungmin JEONG ; Yeon Mi KIM ; KangUk LEE
Journal of Korean Neuropsychiatric Association 2021;60(4):366-378
Objectives:
To assess the satisfaction of dementia patients with telemedicine services. Underlying factors were extracted from a satisfaction dataset, and possible associations among factors were investigated to determine their statistical relevances.
Methods:
A survey was conducted using a questionnaire to determine satisfaction with telemedicine services of patients with dementia in 9 public health centers and 5 designated hospitals in 8 provinces in Gangwon-do from 20 July 2020 to 31 October 2020. Four hundred and ninety-seven users responded to the survey. Factor analysis was performed on survey data and multiple linear regression was used to extract relevant factors.
Results:
The percentage of subjects satisfied with telemedicine services was 78.8%. Thirty-five items of the satisfaction survey indicated that the five factors, that is, necessity (Cronbach’s α 0.952), satisfaction (Cronbach’s α 0.929), medical system reliability (Cronbach’s α 0.924), medical staff reliability (Cronbach’s α 0.924), and geographic vulnerability (Cronbach’s α 0.922), were related to satisfaction with telemedicine services, and that of these, geographic vulnerability was most associated with the need for telemedicine services.
Conclusion
This study shows that dementia patients with experience of telemedicine services were generally satisfied with treatment. Despite its limitations, the satisfaction survey was found to provide a reliable and valid scale for assessing user satisfaction.
6.Correction: Analyses of oligodontia phenotypes and genetic etiologies.
Mengqi ZHOU ; Hong ZHANG ; Heather CAMHI ; Figen SEYMEN ; Mine KORUYUCU ; Yelda KASIMOGLU ; Jung-Wook KIM ; Hera KIM-BERMAN ; Ninna M R YUSON ; Paul J BENKE ; Yiqun WU ; Feng WANG ; Yaqin ZHU ; James P SIMMER ; Jan C-C HU
International Journal of Oral Science 2021;13(1):35-35
7.Analyses of oligodontia phenotypes and genetic etiologies.
Mengqi ZHOU ; Hong ZHANG ; Heather CAMHI ; Figen SEYMEN ; Mine KORUYUCU ; Yelda KASIMOGLU ; Jung-Wook KIM ; Hera KIM-BERMAN ; Ninna M R YUSON ; Paul J BENKE ; Yiqun WU ; Feng WANG ; Yaqin ZHU ; James P SIMMER ; Jan C-C HU
International Journal of Oral Science 2021;13(1):32-32
Oligodontia is the congenital absence of six or more teeth and comprises the more severe forms of tooth agenesis. Many genes have been implicated in the etiology of tooth agenesis, which is highly variable in its clinical presentation. The purpose of this study was to identify associations between genetic mutations and clinical features of oligodontia patients. An online systematic search of papers published from January 1992 to June 2021 identified 381 oligodontia cases meeting the eligibility criteria of causative gene mutation, phenotype description, and radiographic records. Additionally, ten families with oligodontia were recruited and their genetic etiologies were determined by whole-exome sequence analyses. We identified a novel mutation in WNT10A (c.99_105dup) and eight previously reported mutations in WNT10A (c.433 G > A; c.682 T > A; c.318 C > G; c.511.C > T; c.321 C > A), EDAR (c.581 C > T), and LRP6 (c.1003 C > T, c.2747 G > T). Collectively, 20 different causative genes were implicated among those 393 cases with oligodontia. For each causative gene, the mean number of missing teeth per case and the frequency of teeth missing at each position were calculated. Genotype-phenotype correlation analysis indicated that molars agenesis is more likely linked to PAX9 mutations, mandibular first premolar agenesis is least associated with PAX9 mutations. Mandibular incisors and maxillary lateral incisor agenesis are most closely linked to EDA mutations.
Humans
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Phenotype
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Wnt Proteins
8.Impact of Sarcopenia on the Risk of Erosive Esophagitis
Chan Mi HEO ; Tae Jun KIM ; Hyuk LEE ; Jeung Hui PYO ; Yang Won MIN ; Byung Hoon MIN ; Jun Haeng LEE ; Hee Jung SON ; Sun Young BAEK ; Kyunga KIM ; Seungho RYU ; Poong Lyul RHEE ; Jae J KIM
The Korean Journal of Gastroenterology 2020;75(3):132-140
BACKGROUND/AIMS: An association between obesity and erosive esophagitis has been reported, but the effects of sarcopenia and obesity on erosive esophagitis are unknown. This study examined the relationship between obesity, sarcopenia, sarcopenic obesity, and erosive esophagitis in a large population of asymptomatic men and women.METHODS: This study analyzed 32,762 subjects who underwent a comprehensive health check-up, which included upper gastrointestinal endoscopy, from August 2006 to December 2011 by a cross-sectional study. Sarcopenia was defined as a decrease in the appendicular skeletal muscle mass (ASM)/body weight value of two SD or more below the normal means for a younger reference group.RESULTS: The study was carried out on four groups according to obesity and sarcopenic status: normal, obesity, sarcopenic, and sarcopenic obese group. In a multivariable model, the risk of erosive esophagitis was higher in the obese (adjusted OR [aOR] 1.35, 95% CI 1.22–1.49), sarcopenic (aOR 2.12, 95% CI 1.40–3.19), and sarcopenic obese groups (aOR 1.54, 95% CI 1.27–1.87) than in the normal group. The risk of erosive esophagitis was higher in the sarcopenic and sarcopenic obese groups than the obese group; the ORs were 1.63 (95% CI 1.08–2.47) and 1.22 (95% CI 1.01–1.46), respectively. In dose-response analysis, increasing sarcopenia severity showed a positive and graded relationship with the overall, Los Angeles (LA)-B or higher grade, and LA-C erosive esophagitis.CONCLUSIONS: This study suggests that sarcopenia is strongly and progressively associated with erosive esophagitis.
9.Sarcopenia and Muscle Aging: A Brief Overview
Tam DAO ; Alexander E. GREEN ; Yun A KIM ; Sung-Jin BAE ; Ki-Tae HA ; Karim GARIANI ; Mi-ra LEE ; Keir J. MENZIES ; Dongryeol RYU
Endocrinology and Metabolism 2020;35(4):716-732
The world is facing the new challenges of an aging population, and understanding the process of aging has therefore become one of the most important global concerns. Sarcopenia is a condition which is defined by the gradual loss of skeletal muscle mass and function with age. In research and clinical practice, sarcopenia is recognized as a component of geriatric disease and is a current target for drug development. In this review we define this condition and provide an overview of current therapeutic approaches. We further highlight recent findings that describe key pathophysiological phenotypes of this condition, including alterations in muscle fiber types, mitochondrial function, nicotinamide adenine dinucleotide (NAD+) metabolism, myokines, and gut microbiota, in aged muscle compared to young muscle or healthy aged muscle. The last part of this review examines new therapeutic avenues for promising treatment targets. There is still no accepted therapy for sarcopenia in humans. Here we provide a brief review of the current state of research derived from various mouse models or human samples that provide novel routes for the development of effective therapeutics to maintain muscle health during aging.
10.ERK Regulates NeuroD1-mediated Neurite Outgrowth via Proteasomal Degradation
Tae-young LEE ; In-Su CHO ; Narayan BASHYAL ; Francisco J NAYA ; Ming-Jer TSAI ; Jeong Seon YOON ; Jung-Mi CHOI ; Chang-Hwan PARK ; Sung-Soo KIM ; Haeyoung SUH-KIM
Experimental Neurobiology 2020;29(3):189-206
Neurogenic differentiation 1 (NeuroD1) is a class B basic helix-loop-helix (bHLH) transcription factor and regulates differentiation and survival of neuronal and endocrine cells by means of several protein kinases, including extracellular signal-regulated kinase (ERK). However, the effect of phosphorylation on the functions of NeuroD1 by ERK has sparked controversy based on context-dependent differences across diverse species and cell types. Here, we evidenced that ERK-dependent phosphorylation controlled the stability of NeuroD1 and consequently, regulated proneural activity in neuronal cells. A null mutation at the ERK-dependent phosphorylation site, S274A, increased the half-life of NeuroD1 by blocking its ubiquitin-dependent proteasomal degradation. The S274A mutation did not interfere with either the nuclear translocation of NeuroD1 or its heterodimerization with E47, its ubiquitous partner and class A bHLH transcription factor. However, the S274A mutant increased transactivation of the E-box-mediated gene and neurite outgrowth in F11 neuroblastoma cells, compared to the wild-type NeuroD1. Transcriptome and Gene Ontology enrichment analyses indicated that genes involved in axonogenesis and dendrite development were downregulated in NeuroD1 knockout (KO) mice. Overexpression of the S274A mutant salvaged neurite outgrowth in NeuroD1-deficient mice, whereas neurite outgrowth was minimal with S274D, a phosphomimicking mutant. Our data indicated that a longer protein half-life enhanced the overall activity of NeuroD1 in stimulating downstream genes and neuronal differentiation. We propose that blocking ubiquitin-dependent proteasomal degradation may serve as a strategy to promote neuronal activity by stimulating the expression of neuron-specific genes in differentiating neurons.

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