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Bae WJ, Kim S, Ahn JM, Han JH, Lee D. Estrogen-responsive cancer-associated fibroblasts promote invasive property of gastric cancer in a paracrine manner via CD147 production. FASEB J 2022; 36:e22597. [PMID: 36197688 DOI: 10.1096/fj.202200164rr] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 09/15/2022] [Accepted: 09/26/2022] [Indexed: 11/11/2022]
Abstract
Estrogen signaling has been extensively studied, especially in cancers that express estrogen receptor alpha (ERα). However, little is known regarding the effect of estrogen on cancer-associated fibroblasts (CAFs). Here, we explored the role of estrogen signaling of CAFs in gastric cancer (GC) progression. We investigated the phenotypic changes in CAFs upon 17β-estradiol (E2) treatment using ERα-negative/positive CAFs, and the conditioned media (CM) collected from these were compared with regard to cancer cell proliferation, migration, and invasion. A paracrine factor was found using a cytokine array and was confirmed using qRT-PCR, western blotting, and enzyme-linked immunosorbent assays. ERα-CD147-matrix metalloproteinase (MMP) axis was confirmed by knockdown experiments using specific siRNAs. We found that a subset of CAFs expressed ERα. ERα-positive CAFs were responsive to E2, inducing ERα expression in a dose-dependent manner. Although E2 did not induce the proliferation of ERα-positive CAFs, the CM from E2-bound ERα-positive CAFs significantly promoted cancer cell migration and invasion. Cytokine array revealed that CD147 was induced in ERα-positive CAFs upon E2 treatment; this was mediated via ERα. Increased CD147 upregulated MMP2 and MMP9 in CAFs, and also influenced cancer cells in a paracrine manner to increase MMPs and CD147 in cancer cells. High CD147 expression in tumor tissue was associated with a worse prognosis in GC patients. Our data suggest that estrogen signaling activation in CAFs and the byproduct CD147 are among the critical mediators between the interplay of CAFs and cancer cells to facilitate cancer progression.
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Affiliation(s)
- Won Jung Bae
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea.,Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - Seokhwi Kim
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea.,Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - Ji Mi Ahn
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea.,Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - Jae Ho Han
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Dakeun Lee
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea.,Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
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Bae WJ, Woo KJ, Ahn JM, Yang CM, Kim YS, Kim S, Lee D. miR-4742-5p promotes invasiveness of gastric cancer via targeting Rab43: An in vitro study. Biochem Biophys Res Commun 2022; 613:180-186. [PMID: 35597125 DOI: 10.1016/j.bbrc.2022.05.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 05/12/2022] [Indexed: 11/02/2022]
Abstract
miRNA (miR)-4742-5p is a recently identified microRNA regarding progression and metastasis in gastric cancer (GC). However, the biological function of this novel miRNA is largely unknown. We identified that the miR-4742-5p expression level was variably increased in GC cell lines. Suppression of miR-4742-5p using miR-inhibitor reduced the proliferation, migration, and invasion of GC cells with high miR-4742-5p expression, whereas overexpression of miR-4742-5p-mimic enhanced the aforementioned properties in GC cells with low miR-4742-5p expression. miR-4742-5p expression induced the decreases of Zo-1 and E-cadherin expression as well as the increases of vimentin and N-cadherin expression, leading to epithelial-mesenchymal transition (EMT) of cancer cells. RNA sequencing results indicated Ras-related GTP-binding protein 43 (Rab43) as a potential target gene. We identified that the expression of Rab43 is associated with activation of AKT and nuclear factor-kappa B (NF-κB) which are key oncogenic pathways in cancer cells. Our results demonstrate a new component in GC progression, promising a potential therapeutic strategy.
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Affiliation(s)
- Won Jung Bae
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Kyoung-Jin Woo
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea; Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - Ji Mi Ahn
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Chan-Mo Yang
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea; Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - You-Sun Kim
- Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea; Department of Biochemistry, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Seokhwi Kim
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea; Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea.
| | - Dakeun Lee
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea; Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea.
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Kim S, Ahn JM, Bae WJ, Han JH, Lee D. Quantitation of ligand is critical for ligand-dependent MET signalling activation and determines MET-targeted therapeutic response in gastric cancer. Gastric Cancer 2021; 24:577-588. [PMID: 33164142 DOI: 10.1007/s10120-020-01139-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/26/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Despite the promising preclinical antitumor activity of MET-targeting therapies, most clinical trials have failed. We introduced a new concept of quantitation of stroma-induced hepatocyte growth factor (HGF) to assess the actual MET signalling activity in gastric cancer (GC). METHODS We treated serially diluted HGF and conditioned media (CM) from cancer-associated fibroblasts (CAFs) on low MET-expressing cancer cells and investigated the phenotypical and signalling changes. Stromal proportion and MET expression in GC samples were assessed, and gene set enrichment analysis (GSEA) from the public database was performed. The antitumor effect of anti-MET treatment was examined, especially when cancer cells were activated in a ligand-dependent manner. RESULTS Relatively high doses of HGF or high-concentrated CM fully activated MET signalling cascades and promoted cell proliferation/invasion. High stromal proportion denoted worse patient survival in MET-positive GCs than in MET-negative ones. GSEA showed that the gene sets regarding proliferation, migration, and CAF as well as MET pathway signature were enriched in simultaneously MET- and HGF-positive samples. Sufficient ligand-dependent MET signalling activation increased the sensitivity to crizotinib. CONCLUSIONS We conclude that patients whose tumours have a high stromal proportion and at least low MET expression may benefit more from MET-targeted therapies.
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Affiliation(s)
- Seokhwi Kim
- Department of Pathology, Ajou University School of Medicine, 164, Worldcup-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16499, Republic of Korea
| | - Ji Mi Ahn
- Department of Pathology, Ajou University School of Medicine, 164, Worldcup-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16499, Republic of Korea
| | - Won Jung Bae
- Department of Pathology, Ajou University School of Medicine, 164, Worldcup-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16499, Republic of Korea
| | - Jae Ho Han
- Department of Pathology, Ajou University School of Medicine, 164, Worldcup-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16499, Republic of Korea
| | - Dakeun Lee
- Department of Pathology, Ajou University School of Medicine, 164, Worldcup-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16499, Republic of Korea.
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Kim S, Bae WJ, Ahn JM, Heo JH, Kim KM, Choi KW, Sung CO, Lee D. MicroRNA signatures associated with lymph node metastasis in intramucosal gastric cancer. Mod Pathol 2021; 34:672-683. [PMID: 32973329 DOI: 10.1038/s41379-020-00681-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 09/04/2020] [Accepted: 09/07/2020] [Indexed: 02/07/2023]
Abstract
Although a certain proportion of intramucosal carcinomas (IMCs) of the stomach does metastasize, the majority of patients are currently treated with endoscopic resection without lymph node dissection, and this potentially veils any existing metastasis and may put some patients in danger. In this regard, biological markers from the resected IMC that can predict metastasis are warranted. Here, we discovered unique miRNA expression profiles that consist of 21 distinct miRNAs that are specifically upregulated (miR-628-5p, miR-1587, miR-3175, miR-3620-5p, miR-4459, miR-4505, miR-4507, miR-4720-5p, miR-4742-5p, and miR-6779-5p) or downregulated (miR-106b-3p, miR-125a-5p, miR-151b, miR-181d-5p, miR-486-5p, miR-500a-3p, miR-502-3p, miR-1231, miR-3609, and miR-6831-5p) in metastatic (M)-IMC compared to nonmetastatic (N)-IMC, or nonneoplastic gastric mucosa. Intriguingly, most of these selected miRNAs showed stepwise increased or decreased expression from nonneoplastic tissue to N-IMC to M-IMC. This suggests that common oncogenic mechanisms are gradually intensified during the metastatic process. Using a machine-learning algorithm, we demonstrated that such miRNA signatures could distinguish M-IMC from N-IMC. Gene ontology and pathway analysis revealed that TGF-β signaling was enriched from upregulated miRNAs, whereas E2F targets, apoptosis-related, hypoxia-related, and PI3K/AKT/mTOR signaling pathways, were enriched from downregulated miRNAs. Immunohistochemical staining of samples from multiple institutions indicated that PI3K/AKT/mTOR pathway components, MAPK1, phospho-p44/42 MAPK, and pS6 were highly expressed and the expression of SMAD7, a TGF-β pathway component, was decreased in M-IMC, which could aid in distinguishing M-IMC from N-IMC. The miRNA signature discovered in this study is a valuable biological marker for identifying metastatic potential of IMCs, and provides novel insights regarding the metastatic progression of IMC.
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Affiliation(s)
- Seokhwi Kim
- Department of Pathology, Ajou University School of Medicine, Suwon, Korea
| | - Won Jung Bae
- Department of Pathology, Ajou University School of Medicine, Suwon, Korea
| | - Ji Mi Ahn
- Department of Pathology, Ajou University School of Medicine, Suwon, Korea
| | - Jin-Hyung Heo
- Department of Pathology, CHA Bundang Medical Center, CHA University, Seongnam, Korea
| | - Kyoung-Mee Kim
- Department of Pathology and Translational Genomics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Kyeong Woon Choi
- Department of Medical Science, Asan Medical Institute of Convergence Science and Technology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Chang Ohk Sung
- Department of Medical Science, Asan Medical Institute of Convergence Science and Technology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. .,Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
| | - Dakeun Lee
- Department of Pathology, Ajou University School of Medicine, Suwon, Korea.
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Bae WJ, Ahn JM, Byeon HE, Kim S, Lee D. PTPRD-inactivation-induced CXCL8 promotes angiogenesis and metastasis in gastric cancer and is inhibited by metformin. J Exp Clin Cancer Res 2019; 38:484. [PMID: 31805999 PMCID: PMC6896474 DOI: 10.1186/s13046-019-1469-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 10/28/2019] [Indexed: 01/21/2023]
Abstract
Background Protein tyrosine phosphatase receptor delta (PTPRD) is frequently inactivated in various types of cancers. Here, we explored the underlying mechanism of PTPRD-loss-induced cancer metastasis and investigated an efficient treatment option for PTPRD-inactivated gastric cancers (GCs). Methods PTPRD expression was evaluated by immunohistochemistry. Microarray analysis was used to identify differentially expressed genes in PTPRD-inactivated cancer cells. Quantitative reverse transcription (qRT-PCR), western blotting, and/or enzyme-linked immunosorbent assays were used to investigate the PTPRD-CXCL8 axis and the expression of other related genes. An in vitro tube formation assay was performed using HUVECs. The efficacy of metformin was assessed by MTS assay. Results PTPRD was frequently downregulated in GCs and the loss of PTPRD expression was associated with advanced stage, worse overall survival, and a higher risk of distant metastasis. Microarray analysis revealed a significant increase in CXCL8 expression upon loss of PTPRD. This was validated in various GC cell lines using transient and stable PTPRD knockdown. PTPRD-loss-induced angiogenesis was mediated by CXCL8, and the increase in CXCL8 expression was mediated by both ERK and STAT3 signaling. Thus, specific inhibitors targeting ERK or STAT3 abrogated the corresponding signaling nodes and inhibited PTPRD-loss-induced angiogenesis. Additionally, metformin was found to efficiently inhibit PTPRD-loss-induced angiogenesis, decrease cell viability in PTPRD-inactivated cancers, and reverse the decrease in PTPRD expression. Conclusions Thus, the PTPRD-CXCL8 axis may serve as a potential therapeutic target, particularly for the suppression of metastasis in PTPRD-inactivated GCs. Hence, we propose that the therapeutic efficacy of metformin in PTPRD-inactivated cancers should be further investigated.
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Affiliation(s)
- Won Jung Bae
- Department of Pathology, Ajou University School of Medicine, 164, Worldcup-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16499, Republic of Korea
| | - Ji Mi Ahn
- Department of Pathology, Ajou University School of Medicine, 164, Worldcup-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16499, Republic of Korea
| | - Hye Eun Byeon
- Institute of Medical Science, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Seokwhi Kim
- Department of Pathology, Ajou University School of Medicine, 164, Worldcup-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16499, Republic of Korea
| | - Dakeun Lee
- Department of Pathology, Ajou University School of Medicine, 164, Worldcup-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16499, Republic of Korea.
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Kim YB, Ahn JM, Bae WJ, Sung CO, Lee D. Functional loss of ARID1A is tightly associated with high PD-L1 expression in gastric cancer. Int J Cancer 2019; 145:916-926. [PMID: 30664822 DOI: 10.1002/ijc.32140] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 01/16/2019] [Indexed: 12/21/2022]
Abstract
Notwithstanding remarkable treatment success with anti-PD-1 monoclonal antibody, oncogenic mechanism of PD-L1 regulation in gastric cancer (GC) remains poorly understood. We hypothesized that ARID1A might be related to tumor PD-L1 expression in GC. We found that tumor PD-L1 positivity was associated with loss of ARID1A and showed trend toward better survival of patients with various molecular subtypes of GC (experimental set, n = 273). Considering heterogeneous ARID1A expression, we validated this using whole tissue sections (n = 159) and found that loss of ARID1A was correlated with microsatellite instability-high (MSI-H), Epstein-Barr virus (EBV), and PD-L1 positivity. Furthermore, for patients with MSI-H tumors, the degree of PD-L1 expression was significantly higher in ARID1A-deficient tumors. After ARID1A knockdown in GC cell lines, total and membranous PD-L1 protein, and PD-L1 mRNA levels were increased based on Western blot, flow cytometry, and qRT-PCR, respectively. With IFN-γ treatment, PD-L1 expression was significantly increased both in ARID1A-deficient cancer cells and controls, but the increase was not more pronounced in the former. Loss of ARID1A increased PD-L1 via activating AKT signaling, while LY294002 (PI3K inhibitor) decreased PD-L1 levels. Furthermore, we found that 3 MSI-H tumors showing highest expression of PD-L1 had simultaneous KRAS mutation and loss of ARID1A, suggesting a possible synergistic role boosting PD-L1. Our results strongly indicate that loss of ARID1A is tightly associated with high PD-L1 expression in GC. These results would increase our understanding of the oncogenic mechanism of PD-L1 regulation in GC, and also help to find the optimal candidates for immunotherapy.
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Affiliation(s)
- Young-Bae Kim
- Department of Pathology, Ajou University School of Medicine, Suwon, South Korea
| | - Ji Mi Ahn
- Department of Pathology, Ajou University School of Medicine, Suwon, South Korea
| | - Won Jung Bae
- Department of Pathology, Ajou University School of Medicine, Suwon, South Korea
| | - Chang Ohk Sung
- Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Dakeun Lee
- Department of Pathology, Ajou University School of Medicine, Suwon, South Korea
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Abstract
This study aimed to investigate the role of PIN1 on the hepatic differentiation of human dental pulp stem cells (hDPSCs) and its signaling pathway, as well as the potential therapeutic effects of hDPSC transplantation and PIN1 inhibition on CCl4 (carbon tetrachloride)-induced liver fibrosis in mice. The in vitro results showed that hepatic differentiation was suppressed by infection with adenovirus-PIN1 and promoted by PIN1 inhibitor juglone via the downregulation of Wnt3a and β-catenin. Compared with treatment with either hDPSC transplantation or juglone alone, the combination of hDPSCs and juglone into CCl4-injured mice significantly suppressed liver fibrosis and restored serum levels of alanine transaminase, aspartate transaminase, and ammonia. Collectively, the present study shows for the first time that PIN1 inhibition promotes hepatic differentiation of hDPSCs through the Wnt/β-catenin pathway. Furthermore, juglone in combination with hDPSC transplantation effectively treats liver fibrosis, suggesting that hDPSC transplantation with PIN1 inhibition may be a novel therapeutic candidate for the treatment of liver injury.
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Affiliation(s)
- H J Kim
- 1 Department of Oral Physiology, BK21 PLUS Project, and Institute of Translational Dental Sciences, School of Dentistry, Pusan National University, Yangsan, Republic of Korea
| | - Y A Cho
- 2 Department of Oral and Maxillofacial Pathology, Research Center for Tooth and Periodontal Regeneration, and School of Dentistry, Kyung Hee University, Seoul, Republic of Korea
| | - Y M Lee
- 2 Department of Oral and Maxillofacial Pathology, Research Center for Tooth and Periodontal Regeneration, and School of Dentistry, Kyung Hee University, Seoul, Republic of Korea
| | - S Y Lee
- 2 Department of Oral and Maxillofacial Pathology, Research Center for Tooth and Periodontal Regeneration, and School of Dentistry, Kyung Hee University, Seoul, Republic of Korea
| | - W J Bae
- 2 Department of Oral and Maxillofacial Pathology, Research Center for Tooth and Periodontal Regeneration, and School of Dentistry, Kyung Hee University, Seoul, Republic of Korea
| | - E C Kim
- 2 Department of Oral and Maxillofacial Pathology, Research Center for Tooth and Periodontal Regeneration, and School of Dentistry, Kyung Hee University, Seoul, Republic of Korea
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Koo BS, Lee SH, Kim JM, Huang S, Kim SH, Rho YS, Bae WJ, Kang HJ, Kim YS, Moon JH, Lim YC. Oct4 is a critical regulator of stemness in head and neck squamous carcinoma cells. Oncogene 2014; 34:2317-24. [PMID: 24954502 DOI: 10.1038/onc.2014.174] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 04/01/2014] [Accepted: 05/06/2014] [Indexed: 01/02/2023]
Abstract
Cancer stem cells (CSCs) have been suggested as responsible for the initiation and progression of cancers. Octamer-binding transcription factor 4 (Oct4) is an important regulator of embryonic stem cell fate. Here, we investigated whether Oct4 regulates stemness of head and neck squamous carcinoma (HNSC) CSCs. Our study showed that ectopic expression of Oct4 promotes tumor growth through cyclin E activation, increases chemoresistance through ABCC6 expression and enhances tumor invasion through slug expression. Also, Oct4 dedifferentiates differentiated HNSC cells to CSC-like cells. Furthermore, Oct4(high) HNSC CSCs have more stem cell-like traits compared with Oct4(low) cells, such as self-renewal, stem cell markers' expression, chemoresistance, invasion capacity and xenograft tumorigeneity in vitro and in vivo. In addition, knockdown of Oct4 led to markedly lower HNSC CSC stemness. Finally, there was a significant correlation between Oct4 expression and survival of 119 HNSC patients. Collectively, these data suggest that Oct4 may be a critical regulator of HNSC CSCs and its targeting may be potentially valuable in the treatment of HNSC CSCs.
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Affiliation(s)
- B S Koo
- Department of Otolaryngology-Head and Neck Surgery, Cancer Research Institute, Daejeon, Korea
| | - S H Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, Seoul, Korea
| | - J M Kim
- Research Institute for Medical Sciences and Pathology, Chungnam National University College of Medicine, Daejeon, Korea
| | - S Huang
- Research Institute for Medical Sciences and Pathology, Chungnam National University College of Medicine, Daejeon, Korea
| | - S H Kim
- Department of Otolaryngology-Head and Neck Surgery, Cancer Research Institute, Daejeon, Korea
| | - Y S Rho
- Department of Otorhinolaryngology-Head and Neck Surgery, Ewha University School of Medicine, Seoul, Korea
| | - W J Bae
- Department of Otolaryngology-Head and Neck Surgery, Hallym University College of Medicine, Seoul, Korea
| | - H J Kang
- Department of Otorhinolaryngology-Head and Neck Surgery, Research Institute of Medical Science, Konkuk University School of Medicine, Seoul, Korea
| | - Y S Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Research Institute of Medical Science, Konkuk University School of Medicine, Seoul, Korea
| | - J H Moon
- Department of Otorhinolaryngology-Head and Neck Surgery, Research Institute of Medical Science, Konkuk University School of Medicine, Seoul, Korea
| | - Y C Lim
- Department of Otorhinolaryngology-Head and Neck Surgery, Research Institute of Medical Science, Konkuk University School of Medicine, Seoul, Korea
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