Publications by authors named "Elad Hikri"

8 Publications

  • Page 1 of 1

Chemotherapy-induced acute vascular injury involves intracellular generation of ROS via activation of the acid sphingomyelinase pathway.

Cell Signal 2021 Jun 26;82:109969. Epub 2021 Feb 26.

Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA. Electronic address:

Several categories of chemotherapy confer substantial risk for late-term vascular morbidity and mortality. In the present study, we aimed to investigate the mechanism of acute chemotherapy-induced vascular injury in normal tissues. Specifically, we looked at activation of the acid sphingomyelinase (ASMase)/ceramide pathway, which leads to generation of reactive oxygen species (ROS) and induction of oxidative stress that may result in vascular injury. In particular, we focused on two distinct drugs, doxorubicin (DOX) and cisplatin (CIS) and their effects on normal endothelial cells. In vitro, DOX resulted in increased ASMase activity, intra-cellular ROS production and induction of apoptosis. CIS treatment generated significantly reduced effects in endothelial cells. In-vivo, murine femoral arterial blood flow was measured in real-time, during and after DOX or CIS administration, using fluorescence optical imaging system. While DOX caused constriction of small vessels and disintegration of large vessels' wall, CIS induced minor vascular changes in arterial blood flow, correlating with the in vitro findings. These results demonstrate that DOX induces acute vascular injury by increased ROS production, via activation of ASMase/ceramide pathway, while CIS increases ROS production and its immediate extracellular translocation, without causing detectable acute vascular injury. Our findings may potentially lead to the development of new strategies to prevent long-term cardiovascular morbidity in cancer survivors.
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http://dx.doi.org/10.1016/j.cellsig.2021.109969DOI Listing
June 2021

CDK 4/6 Inhibition Overcomes Acquired and Inherent Resistance to PI3Kα Inhibition in Pre-Clinical Models of Head and Neck Squamous Cell Carcinoma.

J Clin Med 2020 Oct 7;9(10). Epub 2020 Oct 7.

Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel.

Activating alterations in , the gene coding for the catalytic subunit of phosphoinositide-3-kinase (PI3K), are prevalent in head and neck squamous cell carcinoma (HNSCC) and thought to be one of the main drivers of these tumors. However, early clinical trials on PI3K inhibitors (PI3Ki) have been disappointing due to the limited durability of the activity of these drugs. To investigate the resistance mechanisms to PI3Ki and attempt to overcome them, we conducted a molecular-based study using both HNSCC cell lines and patient-derived xenografts (PDXs). We sought to simulate and dissect the molecular pathways that come into play in PIK3CA-altered HNSCC treated with isoform-specific PI3Ki (BYL719, GDC0032). In vitro assays of cell viability and protein expression indicate that activation of the mTOR and cyclin D1 pathways is associated with resistance to PI3Ki. Specifically, in BYL719-resistant cells, BYL719 treatment did not induce pS6 and pRB inhibition as detected in BYL719-sensitive cells. By combining PI3Ki with either mammalian target of rapamycin complex 1 (mTORC1) or cyclin D1 kinase (CDK) 4/6 specific inhibitors (RAD001 and abemaciclib, respectively), we were able to overcome the acquired resistance. Furthermore, we found that PI3Ki and CDK 4/6 inhibitors have a synergistic anti-tumor effect when combined in human papillomavirus (HPV)-negative/PIK3CA-WT tumors. These findings provide a rationale for combining PI3Ki and CDK 4/6 inhibitors to enhance anti-tumor efficacy in HNSCC patients.
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http://dx.doi.org/10.3390/jcm9103214DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7601167PMC
October 2020

Pigment epithelium derived factor as a novel multi-target treatment for uterine fibroids.

Reprod Biomed Online 2020 Aug 29;41(2):335-342. Epub 2020 Apr 29.

Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 69978, Ramat-Aviv, Israel.

Research Question: Does recombinant pigment epithelium derived factor (PEDF) have potential in treating uterine fibroids?

Design: In-vitro models that used human leiomyoma and Eker rat uterine leiomyoma (ELT-3) cell lines. The ELT-3 cell line was used to examine cellular targets after adding recombinant PEDF to the culture media. Athymic nude female mice were used as an in-vivo model. They were injected with ELT-3 cells to induce ectopic fibroid lesions, then treated with recombinant PEDF.

Results: RNA expression of PEDF and its receptors was found in both leiomyoma cell lines, as well as the expression of PEDF receptors. Addition of recombinant PEDF to the culture medium of leiomyoma cell lines activated ERK in a time-dependent manner, induced down-regulation of vascular endothelial growth factor mRNA and protein, as well as the mRNAs of oestrogen receptors alpha and beta and inhibited cellular proliferation. Treatment of mice-bearing fibroids with recombinant PEDF reduced fibroid growth rate and resulted in smaller tumours.

Conclusions: This study suggests that recombinant PEDF is a putative novel potent physiological treatment for uterine fibroids. It targets several cornerstones of fibroid pathobiology in parallel, including vascular endothelial growth factor and oestrogen receptors, which are needed for vascularization, and restricts fibroid growth and final size in an animal model.
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http://dx.doi.org/10.1016/j.rbmo.2020.03.024DOI Listing
August 2020

miR-125a Induces HER2 Expression and Sensitivity to Trastuzumab in Triple-Negative Breast Cancer Lines.

Front Oncol 2020 28;10:191. Epub 2020 Feb 28.

Division of Oncology, Rambam Health Care, Haifa, Israel.

The EGFR/HER2 signaling network is an effective therapeutic target for HER2-positive cancers, which are known for their aggressive biological course. Evidence indicates that the EGFR/HER2 network plays a role in the aggressive basal-like subtype as well. Here, we studied the potential role of miR-125a-3p as a modulator of the EGFR/HER2 pathway in basal-like breast cancer. Over-expression of miR-125a-3p reduced the migratory capability of MDA-MB-231 cells and led to an increase in the expression of ErbB2 transcript and protein. The induced ErbB2 responded to trastuzumab and underwent internalization and subsequent intra-lysosomal degradation. Trastuzumab treatment further reduced the migratory capability and induced the apoptosis of the cells. An mouse model, which supported the findings, showed a synergistic effect for miR-125a-3p and trastuzumab. Trastuzumab-treated miR-125a-3p-induced tumors were significantly smaller than control induced tumors. Our findings indicate that, in the basal-like subtype of breast cancer, miR-125a-3p may act as a tumor suppressor. miR-125a-3p induces an increase in the expression of ErbB2 that may render the cells suitable for treatment with anti-HER2 therapies.
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http://dx.doi.org/10.3389/fonc.2020.00191DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7058585PMC
February 2020

Young-onset gastric cancer and Epstein-Barr Virus (EBV) - a major player in the pathogenesis?

BMC Cancer 2020 Jan 14;20(1):34. Epub 2020 Jan 14.

Institute of Oncology, Davidoff Cancer Center, Rabin Medical Center, Ze'ev Jabotinsky Rd 39, 4941492, Petah Tikva, Israel.

Objective: Gastric cancer (GC) is a leading cause of cancer death, occurs predominantly in older age, with increasing incidence in young patients. The Cancer Genome Atlas indicates four subtypes for GC among which Epstein-Barr virus (EBV) subtype is estimated at 8.7%. We aim to determine the prevalence of EBV subtype in young GC patients (≤45 years) compared with an average-onset cohort (≥55 years) and characterize the clinicopathologic pattern of young-onset GC.

Methods: Gastric cancer samples of patients of both cohorts were screened for EBV by qPCR. Additional staining was done for Human epidermal growth factor receptor 2 (HER2), microsatellite instability (MSI) status and Programmed death-ligand 1 (PD-L1). Demographics and clinical data were retrieved from the medical records.

Results: Thirty-nine young-onset and 35 average-onset GC patients were reviewed. There was no apparent difference in tumor location, family history, histology and HER2 status between the cohorts. More young-onset patients were diagnosed with metastatic disease (27% vs 9%, p = 0.0498). EBV was significantly more prevalent in the young-onset cohort (33% vs 11%, p = 0.025). 15/17 EBV positive patients were under the median age of diagnosis for GC in the US (68 years). MSI-H was found only in the average-onset cohort [0% vs 27%, p = 0.001). PD-L1 positivity was higher in the young-onset cohort (31% vs 3%, p = 0.002).

Conclusion: Our study indicates that EBV subtype is more prevalent in young-onset GC and may play a key role in the pathogenesis. Higher rate of PD-L1 positivity in young-onset GC could change treatment strategies. We are currently evaluating these findings in a prospective trial.
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http://dx.doi.org/10.1186/s12885-020-6517-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6961297PMC
January 2020

A novel Fer/FerT targeting compound selectively evokes metabolic stress and necrotic death in malignant cells.

Nat Commun 2017 10 16;8(1):940. Epub 2017 Oct 16.

The Mina and Everard Goodman Faculty of Life-Sciences, Bar-Ilan University, Ramat-Gan, 52900, Israel.

Disruption of the reprogrammed energy management system of malignant cells is a prioritized goal of targeted cancer therapy. Two regulators of this system are the Fer kinase, and its cancer cell specific variant, FerT, both residing in subcellular compartments including the mitochondrial electron transport chain. Here, we show that a newly developed inhibitor of Fer and FerT, E260, selectively evokes metabolic stress in cancer cells by imposing mitochondrial dysfunction and deformation, and onset of energy-consuming autophagy which decreases the cellular ATP level. Notably, Fer was also found to associate with PARP-1 and E260 disrupted this association thereby leading to PARP-1 activation. The cooperative intervention with these metabolic pathways leads to energy crisis and necrotic death in malignant, but not in normal human cells, and to the suppression of tumors growth in vivo. Thus, E260 is a new anti-cancer agent which imposes metabolic stress and cellular death in cancer cells.The tyrosine-kinases Fer/FerT associate with the mitochondrial electron transport chain in cancer cells supporting their metabolic reprogramming. Here the authors discover a compound that disrupts Fer /FerT activity and selectively induces cell death of cancer cell lines displaying anti-tumor activity in vivo.
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http://dx.doi.org/10.1038/s41467-017-00832-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5643328PMC
October 2017

Oncogenic properties of a spermatogenic meiotic variant of fer kinase expressed in somatic cells.

Cancer Res 2014 Nov 18;74(22):6474-85. Epub 2014 Sep 18.

The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.

The kinase Fer and its spermatogenic meiotic variant, FerT, are coexpressed in normal testes and cancerous tumors, but whether they exert related roles in spermatogenic or malignant cells has not been known. Here, we show that Fer and FerT reside in the mitochondria of spermatogenic cells and are harnessed to the reprogrammed mitochondria of colon carcinoma cells. Both kinases bound complex I of the mitochondrial electron transport chain (ETC) in spermatogenic and in colon carcinoma cells, and silencing of either Fer or FerT was sufficient to impair the activity of this complex. Directed mitochondrial accumulation of FerT in nonmalignant NIH3T3 cells increased their ETC complex I activity, ATP production, and survival, contingent upon stress conditions caused by nutrient and oxygen deprivation. Strikingly, directed mitochondrial accumulation of FerT endowed nonmalignant cells with tumor-forming ability. Thus, recruitment of a meiotic mitochondrial component to cancer cell mitochondria highlights a pivotal role for reprogrammed mitochondria in tumorigenesis.
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http://dx.doi.org/10.1158/0008-5472.CAN-14-0058DOI Listing
November 2014

Hsp90 and a tyrosine embedded in the Hsp90 recognition loop are required for the Fer tyrosine kinase activity.

Cell Signal 2009 Apr 30;21(4):588-96. Epub 2008 Dec 30.

The Mina & Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 52900, Israel.

Hsp90 is a key regulator of tyrosine kinases activity and is therefore considered as a promising target for intervention with deregulated signaling pathways in malignant cells. Here we describe a novel Hsp90 client - the intracellular tyrosine kinase, Fer, which is subjected to a unique regulatory regime by this chaperone. Inhibition of Hsp90 activity led to proteasomal degradation of the Fer enzyme. However, circumventing the dependence of Fer accumulation on Hsp90, revealed the dependence of the Fer kinase activity and its ability to phosphorylate Stat3 on the chaperone, expressing the necessity of Hsp90 for its function. Mutation analysis unveiled a tyrosine (Tyr(616)) embedded in the Hsp90 recognition loop, which is required for the kinase activity of Fer. Replacement of this tyrosine by phenylalanine (Y616F) disabled the auto-phosphorylation activity of Fer and abolished its ability to phosphorylate Stat3. Notably, surrounding the replaced Y616F with subtle mutations restored the auto and trans-phosphorylation activities of Fer suggesting that Y(616) is not itself an essential auto-phosphorylation site of the kinase. Taken together, our results portray Hsp90 and its recognition loop as novel positive regulators of the Fer tyrosine kinase stability and activity.
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http://dx.doi.org/10.1016/j.cellsig.2008.12.011DOI Listing
April 2009