Arif Ozgun Harmanci

Dr. Arif Ozgun Harmanci


Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 July 2020 in Journal of Clinical Investigation
Verified
Journal Article
Open access
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Trang NguyenTrang Nguyen
Trang Nguyen
YZYiru Zhang
Yiru Zhang
ESEnyuan Shang
Enyuan Shang
CSChang Shu
Chang Shu
CTConsuelo Torrini
Consuelo Torrini
Markus David SiegelinMarkus David Siegelin
Markus David Siegelin
The Warburg effect is a tumor-related phenomenon that could potentially be targeted therapeutically. Here, we showed that glioblastoma (GBM) cultures and patients’ tumors harbored super-enhancers in several genes related to the Warburg effect. By conducting a transcriptome analysis followed by ChIP-Seq coupled with a comprehensive metabolite analysis in GBM models, we found that FDA-approved global (panobinostat, vorinostat) and selective (romidepsin) histone deacetylase (HDAC) inhibitors elicited metabolic reprogramming in concert with disruption of several Warburg effect–related super-enhancers. Extracellular flux and carbon-tracing analyses revealed that HDAC inhibitors blunted glycolysis in a c-Myc–dependent manner and lowered ATP levels. This resulted in the engagement of oxidative phosphorylation (OXPHOS) driven by elevated fatty acid oxidation (FAO), rendering GBM cells dependent on these pathways. Mechanistically, interference with HDAC1/-2 elicited a suppression of c-Myc protein levels and a concomitant increase in 2 transcriptional drivers of oxidative metabolism, PGC1α and PPARD, suggesting an inverse relationship. Rescue and ChIP experiments indicated that c-Myc bound to the promoter regions of PGC1α and PPARD to counteract their upregulation driven by HDAC1/-2 inhibition. Finally, we demonstrated that combination treatment with HDAC and FAO inhibitors extended animal survival in patient-derived xenograft model systems in vivo more potently than single treatments in the absence of toxicity.

29 July 2020 in Nature Communications
Verified
Journal Article
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JZJing Zhang
Jing Zhang
DLDonghoon Lee
Donghoon Lee
VDVineet Dhiman
Vineet Dhiman
PJPeng Jiang
Peng Jiang
JXJie Xu
Jie Xu
MGMark Gerstein
Mark Gerstein
ENCODE comprises thousands of functional genomics datasets, and the encyclopedia covers hundreds of cell types, providing a universal annotation for genome interpretation. However, for particular applications, it may be advantageous to use a customized annotation. Here, we develop such a custom annotation by leveraging advanced assays, such as eCLIP, Hi-C, and whole-genome STARR-seq on a number of data-rich ENCODE cell types. A key aspect of this annotation is comprehensive and experimentally derived networks of both transcription factors and RNA-binding proteins (TFs and RBPs). Cancer, a disease of system-wide dysregulation, is an ideal application for such a network-based annotation. Specifically, for cancer-associated cell types, we put regulators into hierarchies and measure their network change (rewiring) during oncogenesis. We also extensively survey TF-RBP crosstalk, highlighting how SUB1, a previously uncharacterized RBP, drives aberrant tumor expression and amplifies the effect of MYC, a well-known oncogenic TF. Furthermore, we show how our annotation allows us to place oncogenic transformations in the context of a broad cell space; here, many normal-to-tumor transitions move towards a stem-like state, while oncogene knockdowns show an opposing trend. Finally, we organize the resource into a coherent workflow to prioritize key elements and variants, in addition to regulators. We showcase the application of this prioritization to somatic burdening, cancer differential expression and GWAS. Targeted validations of the prioritized regulators, elements and variants using siRNA knockdowns, CRISPR-based editing, and luciferase assays demonstrate the value of the ENCODE resource.

4 February 2022 in Science Advances
Verified
Journal Article
Open access
JBJames C. Bayley
James C. Bayley
CHCaroline C. Hadley
Caroline C. Hadley
AHArif Ozgun Harmanci
Arif Ozgun Harmanci
AHAkdes S. Harmanci
Akdes S. Harmanci
TKTiemo J. Klisch
Tiemo J. Klisch
Akash PatelAkash Patel
Akash Patel
One-fifth of meningiomas classified as benign by World Health Organization (WHO) histopathological grading will behave malignantly. To better diagnose these tumors, several groups turned to DNA methylation, whereas we combined RNA-sequencing (RNA-seq) and cytogenetics. Both approaches were more accurate than histopathology in identifying aggressive tumors, but whether they revealed similar tumor types was unclear. We therefore performed unbiased DNA methylation, RNA-seq, and cytogenetic profiling on 110 primary meningiomas WHO grade I and II). Each technique distinguished the same three groups (two benign and one malignant) as our previous molecular classification; integrating these methods into one classifier further improved accuracy. Computational modeling revealed strong correlations between transcription and cytogenetic changes, particularly loss of chromosome 1p, in malignant tumors. Applying our classifier to data from previous studies also resolved certain anomalies entailed by grouping tumors by WHO grade. Accurate classification will therefore elucidate meningioma biology as well as improve diagnosis and prognosis.

1 November 2021 in Cell Systems
Verified
Journal Article
Open access
MKMiran Kim
Miran Kim
AHArif Ozgun Harmanci
Arif Ozgun Harmanci
JBJean-Philippe Bossuat
Jean-Philippe Bossuat
SCSergiu Carpov
Sergiu Carpov
JCJung Hee Cheon
Jung Hee Cheon
XJXiaoqian Jiang
Xiaoqian Jiang
Genotype imputation is a fundamental step in genomic data analysis, where missing variant genotypes are predicted using the existing genotypes of nearby ‘tag’ variants. Although researchers can outsource genotype imputation, privacy concerns may prohibit genetic data sharing with an untrusted imputation service. Here, we developed secure genotype imputation using efficient homomorphic encryption (HE) techniques. In HE-based methods, the genotype data is secure while it is in transit, at rest, and in analysis. It can only be decrypted by the owner. We compared secure imputation with three state-of-the-art non-secure methods and found that HE-based methods provide genetic data security with comparable accuracy for common variants. HE-based methods have time and memory requirements that are comparable or lower than the non-secure methods. Our results provide evidence that HE-based methods can practically perform resource-intensive computations for high throughput genetic data analysis. Source code is freely available for download at https://github.com/K-miran/secure-imputation. A record of this paper’s Transparent Peer Review process is included in the Supplemental Information.

10 May 2023 in Cancer Immunology Research
Verified
Journal Article
Closed access
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PDPoonam N. Desai
Poonam N. Desai
BWBofei Wang
Bofei Wang
AFAndre Fonseca
Andre Fonseca
PBPamella Borges
Pamella Borges
FJFatima Zahra Jelloul
Fatima Zahra Jelloul
HAHussein A. Abbas
Hussein A. Abbas
Comprehensive investigation of CD8+ T cells in acute myeloid leukemia (AML) is essential for developing immunotherapeutic strategies beyond immune checkpoint blockade. Herein, we performed single-cell RNA profiling of CD8+ T cells from 3 healthy bone marrow donors and 23 newly diagnosed (NewlyDx) and 8 relapsed/refractory (RelRef) patients with AML. Cells coexpressing canonical exhaustion markers formed a cluster constituting <1% of all CD8+ T cells. We identified two effector CD8+ T-cell subsets characterized by distinct cytokine and metabolic profiles that were differentially enriched in NewlyDx and RelRef patients. We refined a 25-gene CD8-derived signature correlating with therapy resistance, including genes associated with activation, chemoresistance, and terminal differentiation. Pseudotemporal trajectory analysis supported enrichment of a terminally differentiated state in CD8+ T cells with high CD8-derived signature expression at relapse or refractory disease. Higher expression of the 25-gene CD8 AML signature correlated with poorer outcomes in previously untreated patients with AML, suggesting that the bona fide state of CD8+ T cells and their degree of differentiation are clinically relevant. Immune clonotype tracking revealed more phenotypic transitions in CD8 clonotypes in NewlyDx than in RelRef patients. Furthermore, CD8+ T cells from RelRef patients had a higher degree of clonal hyperexpansion associated with terminal differentiation and higher CD8-derived signature expression. Clonotype-derived antigen prediction revealed that most previously unreported clonotypes were patient-specific, suggesting significant heterogeneity in AML immunogenicity. Thus, immunologic reconstitution in AML is likely to be most successful at earlier disease stages when CD8+ T cells are less differentiated and have greater capacity for clonotype transitions.

2 February 2023 in Acta Neuropathologica
Verified
Journal Article
Closed access
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AKA. Basit Khan
A. Basit Khan
CECollin W. English
Collin W. English
WCWilliam C. Chen
William C. Chen
PAPrazwal Athukuri
Prazwal Athukuri
JBJames C. Bayley
James C. Bayley
Akash PatelAkash Patel
Akash Patel