Publications by authors named "Junhui Qin"

4 Publications

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Some pleomorphic adenomas of the breast share PLAG1 rearrangements with the analogous tumour of the salivary glands.

Histopathology 2021 Jul 22. Epub 2021 Jul 22.

Department of Pathology, The Basic Medicine Science and the First Affiliated Hospital of the Air Force Military Medical University, Xi'an, Shaan Xi Province, China.

Aims: Pleomorphic adenoma (PA) of the breast, and especially its malignant transformation, is extremely rare and represents a diagnostic pitfall. Molecular alterations in this entity have not been investigated. We aimed to examine the clinicopathological features of our breast PAs and perform molecular analysis.

Methods And Results: Seven cases of breast PA, including two cases of carcinoma ex PA, were analysed. PLAG1 and HMGA2 gene rearrangements were assayed by fluorescence in-situ hybridisation (FISH) and RNA sequencing (RNA-Seq), respectively. Reverse transcription-polymerase chain reaction (RT-PCR) and Sanger sequencing were used to verify RNA sequencing results. All seven cases of breast PA occurred in women. The histological features were similar to the analogous tumour in salivary glands, including a dual epithelial-myoepithelial component and negativity of oestrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) by immunohistochemistry. Of the two cases with carcinoma ex PA, one demonstrated minimal invasion and one was extensively invasive. PLAG1 rearrangements were identified in two cases (28.6%), but no rearrangements of HMG2A were found. A novel fusion product in PAs, TRPS1-PLAG1, was identified in one case. No patients had recurrence or metastasis with a follow-up period of 6-158 months.

Conclusions: Breast PA is rare, but it is an important differential diagnosis of breast pathology with the potential to develop carcinoma ex PA. We report a novel TRPS1-PLAG1 fusion gene in breast PA.
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July 2021

Isocitrate dehydrogenase 1 mutation enhances 24(S)-hydroxycholesterol production and alters cholesterol homeostasis in glioma.

Oncogene 2020 10 27;39(40):6340-6353. Epub 2020 Aug 27.

State Key Laboratory of Cancer Biology, Department of Pathology, Xijing Hospital and School of Basic Medicine, Fourth Military Medical University, 710032, Xi'an, Shaanxi, China.

Isocitrate dehydrogenase (IDH) mutation is the most important initiating event in gliomagenesis, and the increasing evidence shows that IDH mutation is associated with the metabolic reprogramming in the tumor. Dysregulated cholesterol metabolism is a hallmark of tumor cells, but the cholesterol homeostasis in IDH-mutated glioma is still unknown. In this study, we found that astrocyte-specific mutant IDH1(R132H) knockin reduced the cholesterol contents and damaged the structure of myelin in mouse brains. In U87 and U251 cells, the expression of mutant IDH1 consistently reduced the cholesterol levels. Furthermore, we found that IDH1 mutation enhanced the production of 24(S)-hydroxycholesterol (24-OHC), which is not only the metabolite of cholesterol elimination, but also functions as an endogenous ligand for the liver X receptors (LXRs). In IDH1-mutant glioma cells, the elevated 24-OHC activated LXRs, which consequently accelerated the low-density lipoprotein receptor (LDLR) degradation by upregulating the inducible degrader of the LDLR (IDOL). The reduced LDLR expressions in IDH1-mutant glioma cells abated the uptakes of low-density lipoprotein (LDL) to decrease the cholesterol influx. In addition, the activated LXRs also promoted the cholesterol efflux by elevating the ATP-binding cassette transporter A1 (ABCA1), ABCG1, and apolipoprotein E (ApoE) in both IDH1-mutant astrocytes and glioma cells. As a feedback, the reduced cholesterol levels stimulated the cholesterol biosynthesis, which made IDH1-mutated glioma cells more sensitive to atorvastatin, an inhibitor of 3-hydroxy-3-methylglutaryl-CoA reductase. The altered cholesterol homeostasis regulated by mutant IDH provides a pivotal therapeutical strategy for the IDH-mutated gliomas.
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October 2020

Wild-Type IDH1 and Mutant IDH1 Opposingly Regulate Podoplanin Expression in Glioma.

Transl Oncol 2020 Apr 21;13(4):100758. Epub 2020 Mar 21.

State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, the Fourth Military Medical University, Xi'an, China, 710032; Department of Neurology, Tangdu Hospital, the Fourth Military Medical University, Xi'an, Shaanxi, China, 710032. Electronic address:

Isocitrate dehydrogenase (IDH) mutations occur frequently in lower-grade gliomas, which result in genome-wide epigenetic alterations. The wild-type IDH1 is reported to participate in lipid biosynthesis and amino acid metabolism, but its role in tumorigenesis is still unclear. In this study, the expressions of IDH1 and podoplanin (Pdpn) were determined in IDH-mutated and IDH-wild-type gliomas, and their relationships in glioma were further analyzed. In addition, the regulation of wild-type IDH1 and mutant IDH1 on Pdpn expression was investigated by luciferase assays and promoter methylation analysis. Our study showed that Pdpn was almost undetectable in IDH-mutated glioma but strongly expressed in higher-grade IDH-wild-type glioma. Pdpn overexpression promoted the migration of glioma cells but had little effect on cell growth. Moreover, Pdpn expression was positively correlated with the increased wild-type IDH1 levels in IDH-wild-type glioma. Consistently, the wild-type IDH1 greatly promoted the transcription and expression of Pdpn, but the mutant IDH1 and D-2-hydroxyglutarate significantly suppressed Pdpn expression in glioma cells. Besides, our results revealed that the methylation of CpG islands in the Pdpn promoter was opposingly regulated by wild-type and mutant IDH1 in glioma. Collectively, our results indicated that wild-type and mutant IDH1 opposingly controlled the Pdpn expression in glioma by regulating its promoter methylation, which provides a basis for understanding the relationship between wild-type and mutant IDH1 in epigenetic regulation and tumorigenesis.
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April 2020

Isocitrate dehydrogenase1 mutation reduces the pericyte coverage of microvessels in astrocytic tumours.

J Neurooncol 2019 Jun 19;143(2):187-196. Epub 2019 Apr 19.

Department of Neurology, Tangdu Hospital, The Fourth Military Medical University, Xi'an, 710032, Shaanxi, China.

Introduction: Tumour-associated angiogenesis is associated with the malignancy and poor prognosis of glioma. Isocitrate dehydrogenase (IDH) mutations are present in the majority of lower-grade (WHO grade II and III) and secondary glioblastomas, but their roles in tumour angiogenesis remain unclear.

Methods: Using magnetic resonance imaging (MRI), the cerebral blood flow (CBF) of IDH-mutated glioma was measured and compared with the IDH-wildtype glioma. The densities of microvessels in IDH-mutated and wildtype astrocytoma and glioblastoma were assessed by immunohistochemical (IHC) staining with CD34, and the pericytes were labelled with α-smooth muscle antigen (α-SMA), neural-glial antigen 2 (NG2) and PDGF receptor-β (PDGFR-β), respectively. Furthermore, glia-specific mutant IDH1 knock-in mice were generated to evaluate the roles of mutant IDH1 on brain vascular architectures. The transcriptions of the angiogenesis-related genes were assessed in TCGA datasets, including ANGPT1, PDGFB and VEGFA. The expressions of these genes were further determined by western blot in U87-MG cells expressing a mutant IDH1 or treated with 2-HG.

Results: The MRI results indicated that CBF was reduced in the IDH-mutated gliomas. The IHC staining showed that the pericyte coverages of microvessels were significantly decreased, but the microvessel densities (MVDs) were only slightly decreased in IDH-mutated glioma. The mutant IDH1 knock-in also impeded the pericyte coverage of brain microvessels in mice. Moreover, the TCGA database showed the mRNA levels of angiogenesis factors, including ANGPT1, PDGFB and VEGFA, were downregulated, and their promoters were also highly hyper-methylated in IDH-mutated gliomas. In addition, both mutant IDH1 and D-2-HG could downregulate the expression of these genes in U87-MG cells.

Conclusions: Our results suggested that IDH mutations could reduce the pericyte coverage of microvessels in astrocytic tumours by inhibiting the expression of angiogenesis factors. As vascular pericytes play an essential role in maintaining functional blood vessels to support tumour growth, our findings imply a potential avenue of therapeutic strategy for IDH-mutated gliomas.
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June 2019