Wassim Abou-Kheir

Dr. Wassim Abou-Kheir

Department of Anatomy, Cell Biology, and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut 1107-2020, Lebanon
orcid

Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

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

Representative Publications

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27 February 2012 in Oncogene
Verified
Journal Article
Open access
PDF file
YLY-N Liu
Y-N Liu
JYJ J Yin
J J Yin
Wassim Abou-KheirWassim Abou-Kheir
Wassim Abou-Kheir
PHP G Hynes
P G Hynes
OCO M Casey
O M Casey
KKKathleen Kelly
Kathleen Kelly
Epithelial–mesenchymal transition (EMT) is a developmental program of signaling pathways that determine commitment to epithelial and mesenchymal phenotypes. In the prostate, EMT processes have been implicated in benign prostatic hyperplasia and prostate cancer progression. In a model of Pten- and TP53-null prostate adenocarcinoma that progresses via transforming growth factor β-induced EMT, mesenchymal transformation is characterized by plasticity, leading to various mesenchymal lineages and the production of bone. Here we show that SLUG is a major regulator of mesenchymal differentiation. As microRNAs (miRs) are pleiotropic regulators of differentiation and tumorigenesis, we evaluated miR expression associated with tumorigenesis and EMT. Mir-1 and miR-200 were reduced with progression of prostate adenocarcinoma, and we identify Slug as one of the phylogenetically conserved targets of these miRs. We demonstrate that SLUG is a direct repressor of miR-1 and miR-200 transcription. Thus, SLUG and miR-1/miR-200 act in a self-reinforcing regulatory loop, leading to amplification of EMT. Depletion of Slug inhibited EMT during tumorigenesis, whereas forced expression of miR-1 or miR-200 inhibited both EMT and tumorigenesis in human and mouse model systems. Various miR targets were analyzed, and our findings suggest that miR-1 has roles in regulating EMT and mesenchymal differentiation through Slug and functions in tumor-suppressive programs by regulating additional targets.

28 August 2018 in Frontiers in Oncology
Verified
Journal Article
Open access
PDF file
Hisham BahmadHisham Bahmad
Hisham Bahmad
KCKatia Cheaito
Katia Cheaito
RCReda M. Chalhoub
Reda M. Chalhoub
OHOla Hadadeh
Ola Hadadeh
AMAlissar Monzer
Alissar Monzer
Wassim Abou-KheirWassim Abou-Kheir
Wassim Abou-Kheir
Cancer Stem Cells (CSCs) are a sub-population of cells, identified in most tumors, responsible for the initiation, recurrence, metastatic potential, and resistance of different malignancies. In prostate cancer (PCa), CSCs were identified and thought to be responsible for the generation of the lethal subtype, commonly known as Castration-Resistant Prostate Cancer (CRPC). In vitro models to investigate the properties of CSCs in PCa are highly required. Sphere-formation assay is an in vitro method commonly used to identify CSCs and study their properties. Here, we report the detailed methodology on how to generate and propagate spheres from PCa cell lines and from murine prostate tissue. This model is based on the ability of stem cells to grow in non-adherent serum-free gel matrix. We also describe how to use these spheres in histological and immuno-fluorescent staining assays to assess the differentiation potential of the CSCs. Our results show the sphere-formation Assay (SFA) as a reliable in vitro assay to assess the presence and self-renewal ability of CSCs in different PCa models. This platform presents a useful tool to evaluate the effect of conventional or novel agents on the initiation and self-renewing properties of different tumors. The effects can be directly evaluated through assessment of the sphere-forming efficiency (SFE) over five generations or other downstream assays such as immuno-histochemical analysis of the generated spheres.

1 February 2017 in Placenta
Verified
Journal Article
Closed access
Wassim Abou-KheirWassim Abou-Kheir
Wassim Abou-Kheir
JBJoanna Barrak
Joanna Barrak
OHOla Hadadeh
Ola Hadadeh
GDGeorges Daoud
Georges Daoud

24 September 2024 in World Journal of Clinical Oncology
Verified
Journal Article
Open access
HFHiba Fadlallah
Hiba Fadlallah
JMJad El Masri
Jad El Masri
HFHiam Fakhereddine
Hiam Fakhereddine
JYJoe Youssef
Joe Youssef
CCChrystelle Chemaly
Chrystelle Chemaly
Wassim Abou-KheirWassim Abou-Kheir
Wassim Abou-Kheir
Colorectal cancer (CRC) is the third most common cancer worldwide, and the second most common cause of cancer-related death. In 2020, the estimated number of deaths due to CRC was approximately 930000, accounting for 10% of all cancer deaths worldwide. Accordingly, there is a vast amount of ongoing research aiming to find new and improved treatment modalities for CRC that can potentially increase survival and decrease overall morbidity and mortality. Current management strategies for CRC include surgical procedures for resectable cases, and radiotherapy, chemotherapy, and immunotherapy, in addition to their combination, for non-resectable tumors. Despite these options, CRC remains incurable in 50% of cases. Nonetheless, significant improvements in research techniques have allowed for treatment approaches for CRC to be frequently updated, leading to the availability of new drugs and therapeutic strategies. This review summarizes the most recent therapeutic approaches for CRC, with special emphasis on new strategies that are currently being studied and have great potential to improve the prognosis and lifespan of patients with CRC.

1 January 2015 in International Journal of Endocrinology
Verified
Journal Article
Open access
PDF file
CGC. M. Ghantous
C. M. Ghantous
ZAZ. Azrak
Z. Azrak
SHS. Hanache
S. Hanache
Wassim Abou-KheirWassim Abou-Kheir
Wassim Abou-Kheir
AZAsad Zeidan
Asad Zeidan
Leptin and adiponectin are differentially expressed adipokines in obesity and cardiovascular diseases. Leptin levels are directly associated with adipose tissue mass, while adiponectin levels are downregulated in obesity. Although significantly produced by adipocytes, leptin is also produced by vascular smooth muscle cells and cardiomyocytes. Plasma leptin concentrations are elevated in cases of cardiovascular diseases, such as hypertension, congestive heart failure, and myocardial infarction. As for the event of left ventricular hypertrophy, researchers have been stirring controversy about the role of leptin in this form of cardiac remodeling. In this review, we discuss how leptin has been shown to play an antihypertrophic role in the development of left ventricular hypertrophy throughin vitroexperiments, population-based cross-sectional studies, and longitudinal cohort studies. Conversely, we also examine how leptin may actually promote left ventricular hypertrophy usingin vitroanalysis and human-based univariate and multiple linear stepwise regression analysis. On the other hand, as opposed to leptin’s generally detrimental effects on the cardiovascular system, adiponectin is a cardioprotective hormone that reduces left ventricular and vascular hypertrophy, oxidative stress, and inflammation. In this review, we also highlight adiponectin signaling and its protective actions on the cardiovascular system.

1 March 2012 in Molecular and Cellular Biology
Verified
Journal Article
Closed access
PDF file
YLYen-Nien Liu
Yen-Nien Liu
Wassim Abou-KheirWassim Abou-Kheir
Wassim Abou-Kheir
JYJuan Juan Yin
Juan Juan Yin
LFLei Fang
Lei Fang
PHPaul Hynes
Paul Hynes
KKKathleen Kelly
Kathleen Kelly
Epithelial-mesenchymal transition (EMT) is implicated in various pathological processes within the prostate, including benign prostate hyperplasia (BPH) and prostate cancer progression. However, an ordered sequence of signaling events initiating carcinoma-associated EMT has not been established. In a model of transforming growth factor β (TGFβ)-induced prostatic EMT, SLUG is the dominant regulator of EMT initiation in vitro and in vivo, as demonstrated by the inhibition of EMT following Slug depletion. In contrast, SNAIL depletion was significantly less rate limiting. TGFβ-stimulated KLF4 degradation is required for SLUG induction. Expression of a degradation-resistant KLF4 mutant inhibited EMT, and furthermore, depletion of Klf4 was sufficient to initiate SLUG-dependent EMT. We show that KLF4 and another epithelial determinant, FOXA1, are direct transcriptional inhibitors of SLUG expression in mouse and human prostate cancer cells. Furthermore, self-reinforcing regulatory loops for SLUG-KLF4 and SLUG-FOXA1 lead to SLUG-dependent binding of polycomb repressive complexes to the Klf4 and Foxa1 promoters, silencing transcription and consolidating mesenchymal commitment. Analysis of tissue arrays demonstrated decreased KLF4 and increased SLUG expression in advanced-stage primary prostate cancer, substantiating the involvement of the EMT signaling events described in model systems.