1
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Tan GC, Chan E, Molnar A, Sarkar R, Alexieva D, Isa IM, Robinson S, Zhang S, Ellis P, Langford CF, Guillot PV, Chandrashekran A, Fisk NM, Castellano L, Meister G, Winston RM, Cui W, Baulcombe D, Dibb NJ. 5' isomiR variation is of functional and evolutionary importance. Nucleic Acids Res 2014; 42:9424-35. [PMID: 25056318 PMCID: PMC4132760 DOI: 10.1093/nar/gku656] [Citation(s) in RCA: 178] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3′ and/or 5′ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5′ differences and in support of this we report that a 5′ isomiR-9–1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5′ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes.
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Research Support, Non-U.S. Gov't |
11 |
178 |
2
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Mohamad Nor MH, Ayob N, Mokhtar NM, Raja Ali RA, Tan GC, Wong Z, Shafiee NH, Wong YP, Mustangin M, Nawawi KNM. The Effect of Probiotics (MCP ® BCMC ® Strains) on Hepatic Steatosis, Small Intestinal Mucosal Immune Function, and Intestinal Barrier in Patients with Non-Alcoholic Fatty Liver Disease. Nutrients 2021; 13:nu13093192. [PMID: 34579068 PMCID: PMC8468225 DOI: 10.3390/nu13093192] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/07/2021] [Accepted: 09/09/2021] [Indexed: 12/25/2022] Open
Abstract
Treatment for non-alcoholic fatty liver disease (NAFLD) currently consists of lifestyle modifications such as a low-fat diet, weight loss, and exercise. The gut microbiota forms part of the gut–liver axis and serves as a potential target for NAFLD treatment. We investigated the effect of probiotics on hepatic steatosis, fibrosis, and biochemical blood tests in patients with NAFLD. At the small intestinal mucosal level, we examined the effect of probiotics on the expression of CD4+ and CD8+ T lymphocytes, as well as the tight junction protein zona occluden-1 (ZO-1). This was a randomized, double-blind, placebo-controlled trial involving ultrasound-diagnosed NAFLD patients (n = 39) who were supplemented with either a probiotics sachet (MCP® BCMC® strains) or a placebo for a total of 6 months. Multi-strain probiotics (MCP® BCMC® strains) containing six different Lactobacillus and Bifidobacterium species at a concentration of 30 billion CFU were used. There were no significant changes at the end of the study in terms of hepatic steatosis (probiotics: −21.70 ± 42.6 dB/m, p = 0.052 vs. placebo: −10.72 ± 46.6 dB/m, p = 0.29) and fibrosis levels (probiotics: −0.25 ± 1.77 kPa, p = 0.55 vs. placebo: −0.62 ± 2.37 kPa, p = 0.23) as measured by transient elastography. Likewise, no significant changes were found for both groups for the following parameters: LiverFAST analysis (steatosis, fibrosis and inflammation scores), alanine aminotransferase, total cholesterol, triglycerides, and fasting glucose. In the immunohistochemistry (IHC) analysis, no significant expression changes were seen for CD4+ T lymphocytes in either group (probiotics: −0.33 ± 1.67, p = 0.35 vs. placebo: 0.35 ± 3.25, p = 0.63). However, significant reductions in the expression of CD8+ T lymphocytes (−7.0 ± 13.73, p = 0.04) and ZO-1 (Z-score = −2.86, p = 0.04) were found in the placebo group, but no significant changes in the probiotics group. In this pilot study, the use of probiotics did not result in any significant clinical improvement in NAFLD patients. However, at the microenvironment level (i.e., the small intestinal mucosa), probiotics seemed to be able to stabilize the mucosal immune function and to protect NAFLD patients against increased intestinal permeability. Therefore, probiotics might have a complementary role in treating NAFLD. Further studies with larger sample sizes, a longer duration, and different probiotic strains are needed to evaluate the real benefit of probiotics in NAFLD.
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Randomized Controlled Trial |
4 |
94 |
3
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Wong YP, Khong TY, Tan GC. The Effects of COVID-19 on Placenta and Pregnancy: What Do We Know So Far? Diagnostics (Basel) 2021; 11:diagnostics11010094. [PMID: 33435547 PMCID: PMC7827584 DOI: 10.3390/diagnostics11010094] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/25/2020] [Accepted: 01/07/2021] [Indexed: 12/11/2022] Open
Abstract
The current coronavirus disease 2019 (COVID-19) pandemic, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has inflicted a serious health crisis globally. This virus is associated with a spectrum of respiratory illness ranging from asymptomatic, mild to severe pneumonia, and acute respiratory distress syndrome. Accumulating evidence supports that COVID-19 is not merely a respiratory illness per se, but potentially affects other organ systems including the placenta. SARS-CoV-2 gains access to human cells via angiotensin-converting enzyme 2 (ACE-2). The abundance of ACE-2 on the placental cell surface, especially the syncytiotrophoblasts, could potentially contribute to vertical transplacental transmission to the fetus following maternal COVID-19 infection. Intriguingly, despite the placentas being tested positive for SARS-CoV-2, there are very few newborns that manifest virus-induced diseases. The protective effects of the placental barrier to viral infection, limiting the spread of the virus to newborn infants, remain a mystery. The detrimental role of COVID-19 in pregnancies is largely debatable, although COVID-19 maternal infection has been implicated in unfavorable pregnancy outcomes. In this review, we summarize the pathological features manifested in placenta due to COVID-19 maternal infection that have been previously reported, and relate them to the possible disease manifestation. The potential mechanistic pathways associated with transplacental viral transmission and adverse pregnancy outcomes are also discussed.
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Review |
4 |
91 |
4
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Klöppel S, Chu C, Tan GC, Draganski B, Johnson H, Paulsen JS, Kienzle W, Tabrizi SJ, Ashburner J, Frackowiak RSJ. Automatic detection of preclinical neurodegeneration: presymptomatic Huntington disease. Neurology 2009; 72:426-31. [PMID: 19188573 DOI: 10.1212/01.wnl.0000341768.28646.b6] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Treatment of neurodegenerative diseases is likely to be most beneficial in the very early, possibly preclinical stages of degeneration. We explored the usefulness of fully automatic structural MRI classification methods for detecting subtle degenerative change. The availability of a definitive genetic test for Huntington disease (HD) provides an excellent metric for judging the performance of such methods in gene mutation carriers who are free of symptoms. METHODS Using the gray matter segment of MRI scans, this study explored the usefulness of a multivariate support vector machine to automatically identify presymptomatic HD gene mutation carriers (PSCs) in the absence of any a priori information. A multicenter data set of 96 PSCs and 95 age- and sex-matched controls was studied. The PSC group was subclassified into three groups based on time from predicted clinical onset, an estimate that is a function of DNA mutation size and age. RESULTS Subjects with at least a 33% chance of developing unequivocal signs of HD in 5 years were correctly assigned to the PSC group 69% of the time. Accuracy improved to 83% when regions affected by the disease were selected a priori for analysis. Performance was at chance when the probability of developing symptoms in 5 years was less than 10%. CONCLUSIONS Presymptomatic Huntington disease gene mutation carriers close to estimated diagnostic onset were successfully separated from controls on the basis of single anatomic scans, without additional a priori information. Prior information is required to allow separation when degenerative changes are either subtle or variable.
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Research Support, Non-U.S. Gov't |
16 |
80 |
5
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Kamal H, Tan GC, Ibrahim SF, Shaikh MF, Mohamed IN, Mohamed RMP, Hamid AA, Ugusman A, Kumar J. Alcohol Use Disorder, Neurodegeneration, Alzheimer's and Parkinson's Disease: Interplay Between Oxidative Stress, Neuroimmune Response and Excitotoxicity. Front Cell Neurosci 2020; 14:282. [PMID: 33061892 PMCID: PMC7488355 DOI: 10.3389/fncel.2020.00282] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/10/2020] [Indexed: 12/12/2022] Open
Abstract
Alcohol use disorder (AUD) has been associated with neurodegenerative diseases such as Alzheimer's and Parkinson's disease. Prolonged excessive alcohol intake contributes to increased production of reactive oxygen species that triggers neuroimmune response and cellular apoptosis and necrosis via lipid peroxidation, mitochondrial, protein or DNA damage. Long term binge alcohol consumption also upregulates glutamate receptors, glucocorticoids and reduces reuptake of glutamate in the central nervous system, resulting in glutamate excitotoxicity, and eventually mitochondrial injury and cell death. In this review, we delineate the following principles in alcohol-induced neurodegeneration: (1) alcohol-induced oxidative stress, (2) neuroimmune response toward increased oxidants and lipopolysaccharide, (3) glutamate excitotoxicity and cell injury, and (4) interplay between oxidative stress, neuroimmune response and excitotoxicity leading to neurodegeneration and (5) potential chronic alcohol intake-induced development of neurodegenerative diseases, including Alzheimer's and Parkinson's disease.
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Review |
5 |
79 |
6
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Tan GC, Negro G, Pinggera A, Tizen Laim NMS, Mohamed Rose I, Ceral J, Ryska A, Chin LK, Kamaruddin NA, Mohd Mokhtar N, A. Jamal AR, Sukor N, Solar M, Striessnig J, Brown MJ, Azizan EA. Aldosterone-Producing Adenomas. Hypertension 2017; 70:129-136. [DOI: 10.1161/hypertensionaha.117.09057] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 01/23/2017] [Accepted: 04/27/2017] [Indexed: 11/16/2022]
Abstract
Mutations in
KCNJ5
,
ATP1A1
,
ATP2B3
,
CACNA1D
, and
CTNNB1
are thought to cause the excessive autonomous aldosterone secretion of aldosterone-producing adenomas (APAs). The histopathology of
KCNJ5
mutant APAs, the most common and largest, has been thoroughly investigated and shown to have a zona fasciculata–like composition. This study aims to characterize the histopathologic spectrum of the other genotypes and document the proliferation rate of the different sized APAs. Adrenals from 39 primary aldosteronism patients were immunohistochemically stained for CYP11B2 to confirm diagnosis of an APA. Twenty-eight adenomas had sufficient material for further analysis and were target sequenced at hot spots in the 5 causal genes. Ten adenomas had a
KCNJ5
mutation (35.7%), 7 adenomas had an
ATP1A1
mutation (25%), and 4 adenomas had a
CACNA1D
mutation (14.3%). One novel mutation in exon 28 of
CACNA1D
(V1153G) was identified. The mutation caused a hyperpolarizing shift of the voltage-dependent activation and inactivation and slowed the channel’s inactivation kinetics. Immunohistochemical stainings of CYP17A1 as a zona fasciculata cell marker and Ki67 as a proliferation marker were used.
KCNJ5
mutant adenomas showed a strong expression of CYP17A1, whereas
ATP1A1
/
CACNA1D
mutant adenomas had a predominantly negative expression (
P
value =1.20×10
−4
).
ATP1A1
/
CACNA1D
mutant adenomas had twice the nuclei with intense staining of Ki67 than
KCNJ5
mutant adenomas (0.7% [0.5%–1.9%] versus 0.4% [0.3%–0.7%];
P
value =0.04). Further, 3 adenomas with either an
ATP1A1
mutation or a
CACNA1D
mutation had >30% nuclei with moderate Ki67 staining. In summary, similar to
KCNJ5
mutant APAs,
ATP1A1
and
CACNA1D
mutant adenomas have a seemingly specific histopathologic phenotype.
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8 |
33 |
7
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Fatimah SS, Ng SL, Chua KH, Hayati AR, Tan AE, Tan GC. Value of human amniotic epithelial cells in tissue engineering for cornea. Hum Cell 2011; 23:141-51. [PMID: 21166885 DOI: 10.1111/j.1749-0774.2010.00096.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Human amniotic epithelial cells (hAECs) are potentially one of the key players in tissue engineering due to their easy availability. The aim of the present study was to develop an optimal isolation and transportation technique, as well as to determine the immunophenotype and epithelial gene expression of hAECs. Amnion was mechanically peeled off from the chorion and digested with trypsin-ethylenediaminetetraacetic acid. The isolated hAECs were cultured in medium containing 10 ng/mL epidermal growth factor until P4. The epithelial gene expression, cell surface antigen and protein expression of hAECs were analyzed by quantitative polymerase chain reaction, flow cytometry and immunocytochemistry. hAECs were also cultured in adipogenic, osteogenic and neurogenic induction media. The best cell yield of hAECs was seen in the digestion of 15 pieces of amnion (2 × 2 cm) and isolated 30 min after digestion with trypsin. F12:Dulbecco's modified eagle medium was the best medium for short term storage at 4 °C. hAECs expressed CD9, CD44, CD73 and CD90, and negligibly expressed CD31, CD34, CD45 and CD117. After serial passage, CK3, CK19 and involucrin gene expressions were upregulated, while p63, CK1 and CK14 gene expressions were downregulated. Sustained gene expressions of integrin β1 and CK18 were observed. At initial culture, these cells might have stem-like properties. However, they differentiated after serial passage. Nonetheless, hAECs have epithelial stem cell characteristics and have the potential to differentiate into corneal epithelial cells. Further investigations are still needed to elucidate the mechanism of differentiation involved and to optimize the culture condition for long term in vitro culture.
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Research Support, Non-U.S. Gov't |
14 |
30 |
8
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Fatimah SS, Tan GC, Chua KH, Tan AE, Hayati AR. Effects of epidermal growth factor on the proliferation and cell cycle regulation of cultured human amnion epithelial cells. J Biosci Bioeng 2012; 114:220-7. [PMID: 22578596 DOI: 10.1016/j.jbiosc.2012.03.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 03/13/2012] [Accepted: 03/15/2012] [Indexed: 10/28/2022]
Abstract
Human amnion epithelial cells (HAECs) hold great promise in tissue engineering for regenerative medicine. Large numbers of HAECs are required for this purpose. Hence, exogenous growth factor is added to the culture medium to improve epithelial cells proliferation. The aim of the present study was to determine the effects of epidermal growth factor (EGF) on the proliferation and cell cycle regulation of cultured HAECs. HAECs at P1 were cultured for 7 days in medium containing an equal volume mix of HAM's F12: Dulbecco's Modified Eagles Medium (1:1) supplemented with different concentrations of EGF (0, 5, 10, 20, 30 and 50 ng/ml EGF) in reduced serum. Morphology, growth kinetics and cell cycle analysis using flow cytometry were assessed. Quantitative gene expression for cell cycle control genes, pluripotent transcription factors, epithelial genes and neuronal genes were also determined. EGF enhanced HAECs proliferation with optimal concentration at 10 ng/ml EGF. EGF significantly increased the proportion of HAECs at S- and G2/M-phase of the cell cycle compared to the control. At the end of culture, HAECs remained as diploid cells under cell cycle analysis. EGF significantly decreased the mRNA expression of p21, pRb, p53 and GADD45 in cultured HAECs. EGF also significantly decreased the pluripotent genes expression: Oct-3/4, Sox2 and Nanog; epithelial genes expression: CK14, p63, CK1 and Involucrin; and neuronal gene expression: NSE, NF-M and MAP 2. The results suggested that EGF is a strong mitogen that promotes the proliferation of HAECs through cell cycle regulation. EGF did not promote HAECs differentiation or pluripotent genes expression.
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Research Support, Non-U.S. Gov't |
13 |
27 |
9
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Sahabi K, Selvarajah GT, Abdullah R, Cheah YK, Tan GC. Comparative aspects of microRNA expression in canine and human cancers. J Vet Sci 2018; 19:162-171. [PMID: 28927253 PMCID: PMC5879064 DOI: 10.4142/jvs.2018.19.2.162] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 05/19/2017] [Accepted: 07/14/2017] [Indexed: 12/13/2022] Open
Abstract
MicroRNAs (miRNAs) have important roles in all biological pathways in multicellular organisms. Over 1,400 human miRNAs have been identified, and many are conserved among vertebrates and invertebrates. Regulation of miRNA is the most common mode of post-transcriptional gene regulation. The miRNAs that are involved in the initiation and progression of cancers are termed oncomiRs and several of them have been identified in canine and human cancers. Similarly, several miRNAs have been reported to be down-regulated in cancers of the two species. In this review, current information on the expression and roles of miRNAs in oncogenesis and progression of human and canine cancers, as well the roles miRNAs have in cancer stem cell biology, are highlighted. The potential for the use of miRNAs as therapeutic targets in personalized cancer therapy in domestic dogs and their possible application in human cancer counterparts are also discussed.
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Comparative Study |
7 |
20 |
10
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Chia WK, Cheah FC, Abdul Aziz NH, Kampan NC, Shuib S, Khong TY, Tan GC, Wong YP. A Review of Placenta and Umbilical Cord-Derived Stem Cells and the Immunomodulatory Basis of Their Therapeutic Potential in Bronchopulmonary Dysplasia. Front Pediatr 2021; 9:615508. [PMID: 33791258 PMCID: PMC8006350 DOI: 10.3389/fped.2021.615508] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 02/17/2021] [Indexed: 12/13/2022] Open
Abstract
Bronchopulmonary dysplasia (BPD) is a devastating lung disorder of preterm infants as a result of an aberrant reparative response following exposures to various antenatal and postnatal insults. Despite sophisticated medical treatment in this modern era, the incidence of BPD remains unabated. The current strategies to prevent and treat BPD have met with limited success. The emergence of stem cell therapy may be a potential breakthrough in mitigating this complex chronic lung disorder. Over the last two decades, the human placenta and umbilical cord have gained increasing attention as a highly potential source of stem cells. Placenta-derived stem cells (PDSCs) and umbilical cord-derived stem cells (UCDSCs) display several advantages such as immune tolerance and are generally devoid of ethical constraints, in addition to their stemness qualities. They possess the characteristics of both embryonic and mesenchymal stromal/stem cells. Recently, there are many preclinical studies investigating the use of these cells as therapeutic agents in neonatal disease models for clinical applications. In this review, we describe the preclinical and clinical studies using PDSCs and UCDSCs as treatment in animal models of BPD. The source of these stem cells, routes of administration, and effects on immunomodulation, inflammation and regeneration in the injured lung are also discussed. Lastly, a brief description summarized the completed and ongoing clinical trials using PDSCs and UCDSCs as therapeutic agents in preventing or treating BPD. Due to the complexity of BPD, the development of a safe and efficient therapeutic agent remains a major challenge to both clinicians and researchers.
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Review |
4 |
20 |
11
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Raub SHA, Isa NM, Zailani HA, Omar B, Abdullah MF, Amin WAM, Noor RM, Ayub MC, Abidin Z, Kassim F, Vicknesh V, Zakaria Z, Kamaluddin MA, Tan GC, Syed Husain SNA. Distribution of HPV Genotypes in Cervical Cancer in Multiethnic Malaysia. Asian Pac J Cancer Prev 2014; 15:651-6. [DOI: 10.7314/apjcp.2014.15.2.651] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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11 |
18 |
12
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Wu X, Azizan EAB, Goodchild E, Garg S, Hagiyama M, Cabrera CP, Fernandes-Rosa FL, Boulkroun S, Kuan JL, Tiang Z, David A, Murakami M, Mein CA, Wozniak E, Zhao W, Marker A, Buss F, Saleeb RS, Salsbury J, Tezuka Y, Satoh F, Oki K, Udager AM, Cohen DL, Wachtel H, King PJ, Drake WM, Gurnell M, Ceral J, Ryska A, Mustangin M, Wong YP, Tan GC, Solar M, Reincke M, Rainey WE, Foo RS, Takaoka Y, Murray SA, Zennaro MC, Beuschlein F, Ito A, Brown MJ. Somatic mutations of CADM1 in aldosterone-producing adenomas and gap junction-dependent regulation of aldosterone production. Nat Genet 2023; 55:1009-1021. [PMID: 37291193 PMCID: PMC10260400 DOI: 10.1038/s41588-023-01403-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 04/20/2023] [Indexed: 06/10/2023]
Abstract
Aldosterone-producing adenomas (APAs) are the commonest curable cause of hypertension. Most have gain-of-function somatic mutations of ion channels or transporters. Herein we report the discovery, replication and phenotype of mutations in the neuronal cell adhesion gene CADM1. Independent whole exome sequencing of 40 and 81 APAs found intramembranous p.Val380Asp or p.Gly379Asp variants in two patients whose hypertension and periodic primary aldosteronism were cured by adrenalectomy. Replication identified two more APAs with each variant (total, n = 6). The most upregulated gene (10- to 25-fold) in human adrenocortical H295R cells transduced with the mutations (compared to wildtype) was CYP11B2 (aldosterone synthase), and biological rhythms were the most differentially expressed process. CADM1 knockdown or mutation inhibited gap junction (GJ)-permeable dye transfer. GJ blockade by Gap27 increased CYP11B2 similarly to CADM1 mutation. Human adrenal zona glomerulosa (ZG) expression of GJA1 (the main GJ protein) was patchy, and annular GJs (sequelae of GJ communication) were less prominent in CYP11B2-positive micronodules than adjacent ZG. Somatic mutations of CADM1 cause reversible hypertension and reveal a role for GJ communication in suppressing physiological aldosterone production.
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research-article |
2 |
17 |
13
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Mamat @ Yusof MN, Chew KT, Kampan N, Abd. Aziz NH, Md Zin RR, Tan GC, Shafiee MN. PD-L1 Expression in Endometrial Cancer and Its Association with Clinicopathological Features: A Systematic Review and Meta-Analysis. Cancers (Basel) 2022; 14:3911. [PMID: 36010904 PMCID: PMC9405645 DOI: 10.3390/cancers14163911] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/21/2022] [Accepted: 08/04/2022] [Indexed: 12/03/2022] Open
Abstract
Endometrial cancer (EC) is one of the most common malignancies of the female genital tract and its current treatment mainly relies on surgical removal of the tumour bulk, followed by adjuvant radiotherapy with or without chemotherapy/hormonal therapy. However, the outcomes of these approaches are often unsatisfactory and are associated with severe toxicity and a higher recurrence rate of the disease. Thus, more clinical research exploring novel medical intervention is needed. Involvement of the immune pathway in cancer has become important and the finding of a high positive expression of programmed cell death-ligand 1 (PD-L1) in EC may offer a better targeted therapeutic approach. Numerous studies on the PD-L1 role in EC have been conducted, but the results remained inconclusive. Hence, this systematic review was conducted to provide an update and robust analysis in order to determine the pooled prevalence of PD-L1 expression in EC and evaluate its association with clinicopathological features in different focuses of tumour cells (TC) and immune cells (IC). A comprehensive literature search was conducted using the PubMed, Web of Science, and Scopus databases. Twelve articles between 2016 and 2021 with 3023 EC cases met the inclusion criteria. The effect of PD-L1 expression on the outcome parameters was estimated by the odds ratios (ORs) with 95% confidence intervals (CIs) for each study. The pooled prevalence of PD-L1 was 34.26% and 51.39% in the tumour cell and immune cell, respectively, among women with EC. The PD-L1 expression was significantly associated with Stage III/IV disease (in both TC and IC) and correlated to the presence of lympho-vascular invasion in IC. However, the PD-L1 expression in TC was not associated with the age groups, histology types, myometrial invasion, and lympho-vascular invasion. In IC, PD-L1 expression was not associated with age group, histology type, and myometrial invasion. The meta-analysis survival outcomes of PD-L1 high expression had a significant association with worse OS in IC but not in TC.
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Review |
3 |
17 |
14
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Tan GC, Isa MR, Ng SP, Jamil YMA. Unusual form of superficial spreading microinvasive squamous cell carcinoma of uterine cervix involving the endometrium of uterus. J Obstet Gynaecol Res 2004; 30:363-7. [PMID: 15327449 DOI: 10.1111/j.1447-0756.2004.00210.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Microinvasive squamous cell carcinoma of the uterine cervix is a recognized entity and is defined as carcinoma with invasion of less than 5 mm penetration of the stroma and seldom metastasized. Our patient was a 70-year-old, multiparous woman who had a microinvasive, cervical, squamous cell carcinoma. The tumor had spread superficially into the entire endometrial cavity up to the fundus, totally replacing the columnar epithelium. This is an extremely rare phenomenon, with fewer than 20 cases reported so far in the literature.
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21 |
15 |
15
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Fatimah SS, Chua K, Tan GC, Azmi TI, Tan AE, Abdul Rahman H. Organotypic culture of human amnion cells in air-liquid interface as a potential substitute for skin regeneration. Cytotherapy 2013; 15:1030-41. [PMID: 23830235 DOI: 10.1016/j.jcyt.2013.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Revised: 05/07/2013] [Accepted: 05/08/2013] [Indexed: 11/13/2022]
Abstract
BACKGROUND AIMS The aim of the present study was to evaluate the effects of air-liquid interface on the differentiation potential of human amnion epithelial cells (HAECs) to skin-like substitute in organotypic culture. METHODS HAECs at passage 1-2 were seeded onto a fibrin layer populated with human amnion mesenchymal cells to form the organotypic cultures. The organotypic HAECs were then cultured for 7, 14 and 21 d in two types of culture system: the submerged culture and the air-liquid interface culture. Cell morphogenesis was examined under the light and electron microscopes (transmission and scanning) and analyzed by immunohistochemistry. RESULTS Organotypic HAECs formed a single layer epithelium after 3 wk in submerged as well as air-liquid interface cultures. Ultrastructurally, desmosomes were observed in organotypic HAECs cultured in the air-liquid interface but not in the submerged culture. The presence of desmosomes marked the onset of early epidermal differentiation. Organotypic HAECs were positive against anti-CK18 and anti-CK14 in both the submerged and the air-liquid interface cultures. The co-expression of CK14 and CK18 suggested that differentiation of HAECs into skin may follow the process of embryonic skin development. However, weak expression of CK14 was observed after 2 and 3 wk of culture in air-liquid interface. CK10, involucrin, type IV collagen and laminin-5 expression was absent in organotypic HAECs. This observation reflects the initial process of embryonic epidermal differentiation and stratification. CONCLUSIONS Results from the present study suggest that the air-liquid interface could stimulate early differentiation of organotypic HAECs to epidermal cells, with a potential use for skin regeneration.
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12 |
15 |
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Wong YP, Tan GC, Omar SZ, Mustangin M, Singh Y, Salker MS, Abd Aziz NH, Shafiee MN. SARS-CoV-2 Infection in Pregnancy: Placental Histomorphological Patterns, Disease Severity and Perinatal Outcomes. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:9517. [PMID: 35954874 PMCID: PMC9368100 DOI: 10.3390/ijerph19159517] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 07/28/2022] [Accepted: 07/29/2022] [Indexed: 12/12/2022]
Abstract
The association between maternal COVID-19 infection, placental histomorphology and perinatal outcomes is uncertain. The published studies on how placental structure is affected after SARS-CoV-2 virus in COVID-19-infected pregnant women are lacking. We investigated the effects of maternal SARS-CoV-2 infection on placental histomorphology and pregnancy outcomes. A retrospective cohort study on 47 pregnant women with confirmed SARS-CoV-2 infection, matched with non-infected controls, was conducted. Relevant clinicopathological data and primary birth outcomes were recorded. Histomorphology and SARS-CoV-2 immunohistochemistry analyses of placental tissues were performed. Only 1 of 47 cases showed SARS-CoV-2 immunoreactivity in the syncytiotrophoblasts. Histologically, decidual vasculopathy (n = 22/47, p = 0.004), maternal vascular thrombosis (n = 9/47, p = 0.015) and chronic histiocytic intervillositis (n = 10/47, p = 0.027) were significantly higher in the COVID-19-infected placentas when compared to the control group. Maternal vascular thrombosis was a significant feature in the active COVID-19 group. A significant lower gestational age (p < 0.001)) at delivery and a higher caesarean section rate (p = 0.007) were observed in the active SARS-CoV-2-infected cases, resulting in a significant lower fetal-placental weight ratio (p = 0.022) and poorer Apgar score (p < 0.001). Notably, active (p = 0.027), symptomatic (p = 0.039), severe-critical (p = 0.002) maternal COVID-19 infection and placental inflammation (p = 0.011) were associated with an increased risk of preterm delivery. Altered placental villous maturation and severe-critical maternal COVID-19 infection were associated with an elevated risk of poor Apgar scores at birth (p = 0.018) and maternal mortality (p = 0.023), respectively.
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Hayati AR, Cheah FC, Tan AE, Tan GC. Insulin-like growth factor-1 receptor expression in the placentae of diabetic and normal pregnancies. Early Hum Dev 2007; 83:41-6. [PMID: 16750336 DOI: 10.1016/j.earlhumdev.2006.04.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Revised: 01/09/2006] [Accepted: 04/06/2006] [Indexed: 12/21/2022]
Abstract
BACKGROUND Septal hypertrophic cardiomyopathy (sHCM) is a characteristic anomaly of the infant of diabetic mother (IDM). Insulin-like growth factor-1 (IGF-1) has been identified as a mediator of tissue overgrowth and we have previously shown that maternal IGF-1 levels were significantly elevated among neonates with asymmetrical sHCM. IGF-1 does not cross the placenta; it exerts physiologic action through binding to the IGF-1 receptor (IGF-1R). Localisation and expression of IGF-1R in term diabetic pregnancies are largely unclear. We have studied IGF-1R in the placentae of diabetic and normal pregnancies and this receptor expression in association with neonates with sHCM. METHODS IGF-1R localization and expression in the placentae of six diabetic pregnancies associated with neonatal sHCM were compared with six each of randomly selected diabetic and normal pregnancies without neonatal sHCM by immunohistochemistry. The staining for IGF-1R in the deciduas, cytotrophoblasts, syncytiotrophoblasts and villous endothelium for these 18 samples were assessed and scored by two pathologists who were blinded to the respective diagnoses. RESULTS Placental IGF-1R staining was negative in the villous endothelium for all three groups. IGF-1R staining was present in deciduas, cytotrophoblasts and syncytiotrophoblasts but the staining was weaker in the entire group of infants with sHCM compared to those without sHCM. CONCLUSIONS IGF-1R is localized in all cell types of the placenta except in villous endothelium. Weaker placental IGF-1R staining in the placentae of diabetic pregnancies associated with sHCM suggests reduced expression of IGF-1R. This may be a down-regulatory response to elevated maternal IGF with neonatal sHCM outcome.
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Teoh HK, Chong PP, Abdullah M, Sekawi Z, Tan GC, Leong CF, Cheong SK. Small interfering RNA silencing of interleukin-6 in mesenchymal stromal cells inhibits multiple myeloma cell growth. Leuk Res 2016; 40:44-53. [DOI: 10.1016/j.leukres.2015.10.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 10/09/2015] [Accepted: 10/11/2015] [Indexed: 12/21/2022]
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Ang PP, Tan GC, Karim N, Wong YP. Diagnostic Value of the EZH2 Immunomarker in Malignant Effusion Cytology. Acta Cytol 2019; 64:248-255. [PMID: 31352449 DOI: 10.1159/000501406] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 06/09/2019] [Indexed: 12/15/2022]
Abstract
BACKGROUND Differentiating reactive mesothelial cells from metastatic carcinoma in effusion cytology is a challenging task. The application of at least 4 monoclonal antibodies including 2 epithelial markers (Ber-EP4, MOC-31, CEA, or B72.3) and 2 mesothelial markers (calretinin, WT-1, CK5/6, or HBME-1) are often useful in this distinction; however, it is not readily available in many resource-limited developing countries. Aberrant immunoexpression of enhancer of zeste homolog 2 (EZH2), a transcriptional repressor involved in cancer progression, is observed widely in various malignancy. In this study, we evaluate the diagnostic value of EZH2 as a single reliable immunomarker for malignancy in effusion samples. METHODS A total of 108 pleural, peritoneal, and pericardial effusions/washings diagnosed as unequivocally reactive (n = 41) and metastatic carcinoma (n = 67) by cytomorphology over 18 months were reviewed. Among the metastatic carcinoma cases, 54 were adenocarcinoma and others were squamous cell carcinoma (n = 1), carcinosarcoma (n = 1), and carcinoma of undefined histological subtypes (n = 11). Cell block sections were immunostained by EZH2 (Cell Marque, USA). The percentages of EZH2-immunolabeled cells over the total cells of interest were calculated. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cut-off score to define EZH2 immunopositivity. RESULTS A threshold of 8% EZH2-immunolabeled cells allows distinction between malignant and reactive mesothelial cells, with 95.5% sensitivity, 100% specificity, 100% positive predictive value, and 93.2% negative predictive value (p < 0.0001). The area under the curve was 0.988. CONCLUSION EZH2 is a promising diagnostic biomarker for malignancy in effusion cytology which is inexpensive yet trustworthy and could potentially be used routinely in countries under considerable economic constraints.
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Wong YP, Sharifah NA, Tan GC, Gill AJ, Ali SZ. Intrathyroidal oxyphilic parathyroid carcinoma: A potential diagnostic caveat in cytology? Diagn Cytopathol 2016; 44:688-92. [PMID: 27229757 DOI: 10.1002/dc.23493] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 03/22/2016] [Accepted: 04/18/2016] [Indexed: 11/11/2022]
Abstract
Oxyphilic (oncocytic) parathyroid lesions are very uncommon and their cytological features are rarely described. Due to the similarities in anatomical location and indistinguishable cytomorphological features, these lesions are easily confused with neoplastic and non-neoplastic thyroid lesions on fine needle aspiration (FNA). The diagnosis becomes more challenging in cases of unusual intrathyroidal location of the parathyroid lesions in the absence of clinical evidence of hyperparathyroidism, which simulate thyroid nodules clinically. We describe a case of intrathyroidal oxyphilic parathyroid carcinoma in a 66-year-old female, who presented with a dominant left "thyroid" nodule. FNA smears were cellular, comprising predominantly of oxyphilic cells arranged in papillary-like architecture with occasional nuclear grooves, which was mistaken for oncocytic variant of papillary carcinoma of the thyroid. The histological diagnosis of oxyphilic parathyroid "adenoma" was made following total thyroidectomy. The tumor, unfortunately, recurred 7 years later with associated multiple lung metastases. When dealing with thyroid lesions comprising predominantly of oncocytic cells, one should consider oxyphilic parathyroid neoplasms as one of the differential diagnosis. In difficult equivocal cases, a panel of immunocytochemical stains (PTH, GATA3, TTF-1, PAX8, and thyroglobulin) can be helpful. In addition, a combination of valuable clinical, radiological, and laboratory data, including serum calcium and parathyroid hormone levels are key to arriving at an accurate cytological diagnosis. Diagn. Cytopathol. 2016;44:688-692. © 2016 Wiley Periodicals, Inc.
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Wong YP, Cheah FC, Wong KK, Shah SA, Phon SE, Ng BK, Lim PS, Khong TY, Tan GC. Gardnerella vaginalis infection in pregnancy: Effects on placental development and neonatal outcomes. Placenta 2022; 120:79-87. [PMID: 35231793 DOI: 10.1016/j.placenta.2022.02.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 02/06/2022] [Accepted: 02/22/2022] [Indexed: 12/14/2022]
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Tan GC, Hamilton SG, Gibson P, Simpson JA. Ruptured diaphragm: experience in a major accident centre over a ten-year period. THE AUSTRALIAN AND NEW ZEALAND JOURNAL OF SURGERY 1973; 43:163-8. [PMID: 4533428 DOI: 10.1111/j.1445-2197.1973.tb07332.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Tan GC, England EJ, Low AI. Angiomyolipoma: a rare and interesting tumour of the kidney. THE AUSTRALIAN AND NEW ZEALAND JOURNAL OF SURGERY 1972; 42:75-9. [PMID: 4512551 DOI: 10.1111/j.1445-2197.1972.tb06747.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Ko CCH, Chia WK, Selvarajah GT, Cheah YK, Wong YP, Tan GC. The Role of Breast Cancer Stem Cell-Related Biomarkers as Prognostic Factors. Diagnostics (Basel) 2020; 10:diagnostics10090721. [PMID: 32961774 PMCID: PMC7555329 DOI: 10.3390/diagnostics10090721] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/13/2020] [Accepted: 09/16/2020] [Indexed: 02/06/2023] Open
Abstract
Breast cancer is one of the leading causes of cancer-related deaths in women worldwide, and its incidence is on the rise. A small fraction of cancer stem cells was identified within the tumour bulk, which are regarded as cancer-initiating cells, possess self-renewal and propagation potential, and a key driver for tumour heterogeneity and disease progression. Cancer heterogeneity reduces the overall efficacy of chemotherapy and contributes to treatment failure and relapse. The cell-surface and subcellular biomarkers related to breast cancer stem cell (BCSC) phenotypes are increasingly being recognised. These biomarkers are useful for the isolation of BCSCs and can serve as potential therapeutic targets and prognostic tools to monitor treatment responses. Recently, the role of noncoding microRNAs (miRNAs) has extensively been explored as novel biomarker molecules for breast cancer diagnosis and prognosis with high specificity and sensitivity. An in-depth understanding of the biological roles of miRNA in breast carcinogenesis provides insights into the pathways of cancer development and its utility for disease prognostication. This review gives an overview of stem cells, highlights the biomarkers expressed in BCSCs and describes their potential role as prognostic indicators.
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Abstract
Our objectives were to determine the perinatal autopsy rate in a tertiary hospital in Malaysia and to quantify the value of the perinatal autopsy. All stillbirths, miscarriages, therapeutic abortions, and neonatal deaths between January 1, 2004, and August 31, 2009, were identified from the archives. The autopsy findings were compared with the clinical diagnoses. The autopsy reports were also reviewed to determine if it would be possible to improve the quality of the autopsies. There were 807 perinatal deaths, of which 36 (4.5%) included an autopsy. There were ethnic differences in the rate of autopsy, with the lowest rate among the Malays. The autopsy provided the diagnosis, changed the clinical diagnosis, or revealed additional findings in 58.3% of cases. Ancillary testing, such as microbiology, chromosomal analysis, and biochemistry, could improve the quality of the autopsy. This study provides further data on the perinatal autopsy rate from an emerging and developing country. It reaffirms the value of the perinatal autopsy. Attempts must be made to improve on the low autopsy rate while recognizing that the performance of autopsies can be enhanced through the use of ancillary testing.
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