Publications by authors named "Ramzi M Mohammad"

114 Publications

Selinexor in combination with R-CHOP for frontline treatment of non-Hodgkin lymphoma: results of a phase 1 study.

Clin Cancer Res 2021 Mar 30. Epub 2021 Mar 30.

Department of Oncology, Wayne State University School of Medicine, Karmanos Cancer Institute.

Background: The nuclear exporter protein exportin-1 (XPO1) is overexpressed in non-Hodgkin's lymphoma (NHL) and correlates with poor prognosis. We evaluated enhancing R-CHOP activity in NHL by targeted inhibition of XPO1 using the Selective Inhibitor of Nuclear Export (SINE) compounds, selinexor and eltanexor.

Methods: We evaluated the anti-tumor activity of SINE compounds in combination with CHO chemotherapy and Newly diagnosed NHL patients in a phase 1 dose escalation study received R-CHOP for 6 cycles with weekly selinexor (60, 80, and 100 mg), then selinexor maintenance therapy for one year. RT-PCR, Western Blotting and RNA-seq was performed on patient blood samples.

Results: SINE compounds synergized with CHO in NHL cell lines and in our murine xenograft model. In our phase 1 study, selinexor was dosed at 60 mg (n=6) and 80 mg (n=6). The most common adverse events (AEs) among 12 patients were fatigue (67%) and nausea (100%). Grade 3-4 AEs were infrequent. 10 evaluable patients had an ORR of 100% and CR rate of 90% with sustained remissions (median follow up: 476 days). Maximally tolerated dose (MTD) was not reached, however the recommended Phase 2 dose was 60 mg selinexor weekly after evaluating tolerability and discontinuation rates for each dose cohort. Analysis of patient blood samples revealed down-regulation of XPO1 and several pro-survival markers.

Conclusion: SINE compounds enhance the activity of CHO and Selinexor in combination with R-CHOP was generally well-tolerated and showed encouraging efficacy in NHL. (NCT03147885).
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http://dx.doi.org/10.1158/1078-0432.CCR-20-4929DOI Listing
March 2021

Author Correction: The nuclear export protein XPO1 - from biology to targeted therapy.

Nat Rev Clin Oncol 2021 Mar;18(3):190

Karmanos Cancer Institute, Department of Oncology, Wayne State University School of Medicine, Detroit, MI, USA.

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http://dx.doi.org/10.1038/s41571-020-00454-0DOI Listing
March 2021

The nuclear export protein XPO1 - from biology to targeted therapy.

Nat Rev Clin Oncol 2021 Mar 10;18(3):152-169. Epub 2020 Nov 10.

Karmanos Cancer Institute, Department of Oncology, Wayne State University School of Medicine, Detroit, MI, USA.

Exportin 1 (XPO1), also known as chromosome region maintenance protein 1, plays a crucial role in maintaining cellular homeostasis via the regulated export of a range of cargoes, including proteins and several classes of RNAs, from the nucleus to the cytoplasm. Dysregulation of this protein plays a pivotal role in the development of various solid and haematological malignancies. Furthermore, XPO1 is associated with resistance to several standard-of-care therapies, including chemotherapies and targeted therapies, making it an attractive target of novel cancer therapies. Over the years, a number of selective inhibitors of nuclear export have been developed. However, only selinexor has been clinically validated. The novel mechanism of action of XPO1 inhibitors implies a different toxicity profile to that of other agents and has proved challenging in certain settings. Nonetheless, data from clinical trials have led to the approval of the XPO1 inhibitor selinexor (plus dexamethasone) as a fifth-line therapy for patients with multiple myeloma and as a monotherapy for patients with relapsed and/or refractory diffuse large B cell lymphoma. In this Review, we summarize the progress and challenges in the development of nuclear export inhibitors and discuss the potential of emerging combination therapies and biomarkers of response.
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http://dx.doi.org/10.1038/s41571-020-00442-4DOI Listing
March 2021

Calcium Release-Activated Calcium (CRAC) Channel Inhibition Suppresses Pancreatic Ductal Adenocarcinoma Cell Proliferation and Patient-Derived Tumor Growth.

Cancers (Basel) 2020 Mar 22;12(3). Epub 2020 Mar 22.

Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201, USA.

Pancreatic ductal adenocarcinoma (PDAC) remains an unmet clinical problem in urgent need of newer molecularly driven treatment modalities. Calcium signals, particularly those associated with calcium release-activated calcium (CRAC) channels, are known to influence the development, growth, and metastasis of many cancers. This is the first study investigating the impact of CRAC channel inhibition on PDAC cell lines and patient-derived tumor models. PDAC cell lines were exposed to a novel CRAC channel inhibitor, RP4010, in the presence or absence of standard of care drugs such as gemcitabine and nab-paclitaxel. The in vivo efficacy of RP4010 was evaluated in a hyaluronan-positive PDAC patient-derived xenograft (PDx) in the presence or absence of chemotherapeutic agents. Treatment of PDAC cell lines with single-agent RP4010 decreased cell growth, while the combination with gemcitabine/nab-paclitaxel exhibited synergy at certain dose combinations. Molecular analysis showed that RP4010 modulated the levels of markers associated with CRAC channel signaling pathways. Further, the combination treatment was observed to accentuate the effect of RP4010 on molecular markers of CRAC signaling. Anti-tumor activity of RP4010 was enhanced in the presence of gemcitabine/nab-paclitaxel in a PDAC PDx model. Our study indicates that targeting CRAC channel could be a viable therapeutic option in PDAC that warrants further clinical evaluation.
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http://dx.doi.org/10.3390/cancers12030750DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7140111PMC
March 2020

Targeting XPO1 and PAK4 in 8505C Anaplastic Thyroid Cancer Cells: Putative Implications for Overcoming Lenvatinib Therapy Resistance.

Int J Mol Sci 2019 Dec 29;21(1). Epub 2019 Dec 29.

Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201, USA.

Lenvatinib is a multitargeted tyrosine kinase inhibitor (TKI) that shows improved median progression-free survival (PFS) in patients with thyroid carcinomas. However, virtually all patients ultimately progress, indicating the need for a better understanding of the mechanisms of resistance. Here, we examined the molecular profile of anaplastic thyroid cancer cells (8505C) exposed to lenvatinib and found that long-term exposure to lenvatinib caused phenotypic changes. Consistent with change toward mesenchymal morphology, activation of pro-survival signaling, nuclear exporter protein exportin 1 (XPO1) and Rho GTPase effector p21 activated kinases (PAK) was also observed. RNA-seq analysis showed that prolonged lenvatinib treatment caused alterations in numerous cellular pathways and several oncogenes such as (carcinoembryonic antigen-related cell adhesion molecule) and (Nuclear protein 1) were also upregulated. Further, we evaluated the impact of XPO1 and PAK4 inhibition in the presence or absence of lenvatinib. Targeted inhibition of XPO1 and PAK4 could sensitize the 8505C cells to lenvatinib. Both XPO1 and PAK4 inhibitors, when combined with lenvatinib, showed superior anti-tumor activity in 8505C sub-cutaneous xenograft. These studies bring forward novel drug combinations to complement lenvatinib for treating anaplastic thyroid cancer. Such combinations may possibly reduce the chances of lenvatinib resistance in thyroid cancer patients.
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http://dx.doi.org/10.3390/ijms21010237DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6982268PMC
December 2019

Preclinical Assessment with Clinical Validation of Selinexor with Gemcitabine and Nab-Paclitaxel for the Treatment of Pancreatic Ductal Adenocarcinoma.

Clin Cancer Res 2020 03 12;26(6):1338-1348. Epub 2019 Dec 12.

Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan.

Purpose: Pancreatic ductal adenocarcinoma (PDAC) remains a deadly disease urgently requiring new treatments. Overexpression of the protein transporter exportin-1 (XPO1) leads to mislocalization of tumor-suppressor proteins (TSP) and their inactivation. Earlier, we showed that blocking XPO1 by CRISPR/Cas9 validated Selective Inhibitor of Nuclear Export (SINE) compounds (selinexor and analogs) restores the antitumor activity of multiple TSPs leading to suppression of PDAC and in orthotopic models.

Experimental Design: We evaluate the synergy between SINE compounds and standard-of-care treatments in preclinical models and in a PDAC Phase Ib trial.

Results: SINE compounds synergize with gemcitabine (GEM) and nanoparticle albumin-bound (nab)-paclitaxel leading to suppression of PDAC cellular growth and cancer stem cell (CSC) spheroids disintegration. Label-free quantitative proteome profiling with nuclear and cytoplasmic enrichment showed superior enhancement in nuclear protein fraction in combination treatment. Selinexor inhibited the growth of PDAC CSC and two patient-derived (PDX) subcutaneous xenografts. Selinexor-GEM-nab-paclitaxel blocked PDX and orthotopic tumor growth. In a phase 1b study (NCT02178436), 9 patients were exposed to selinexor (60 mg oral) with GEM (1,000 mg/m i.v.) and nab-paclitaxel (125 mg/m i.v.) on days 1, 8, and 15 of 28-day cycle. Two patients showed partial response, and 2 had stable disease. An outstanding, durable objective response was observed in one of the responders with progression-free survival of 16 months and overall survival of 22 months.

Conclusions: Our preclinical and ongoing clinical study lends support to the use of selinexor-GEM-nab-paclitaxel as an effective therapy for metastatic PDAC.
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http://dx.doi.org/10.1158/1078-0432.CCR-19-1728DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7073299PMC
March 2020

PAK4-NAMPT Dual Inhibition as a Novel Strategy for Therapy Resistant Pancreatic Neuroendocrine Tumors.

Cancers (Basel) 2019 Nov 29;11(12). Epub 2019 Nov 29.

Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201, USA.

Pancreatic neuroendocrine tumors (PNET) remain an unmet clinical need. In this study, we show that targeting both nicotinamide phosphoribosyltransferase (NAMPT) and p21-activated kinase 4 (PAK4) could become a synthetic lethal strategy for PNET. The expression of PAK4 and NAMPT was found to be higher in PNET tissue compared to normal cells. PAK4-NAMPT dual RNAi suppressed proliferation of PNET cell lines. Treatment with KPT-9274 (currently in a Phase I trial or analogs, PF3758309 (the PAK4 selective inhibitor) or FK866 (the NAMPT inhibitor)) suppressed the growth of PNET cell lines and synergized with the mammalian target of rapamycin (mTOR) inhibitors everolimus and INK-128. Molecular analysis of the combination treatment showed down-regulation of known everolimus resistance drivers. KPT-9274 suppressed NAD pool and ATP levels in PNET cell lines. Metabolomic profiling showed a statistically significant alteration in cellular energetic pathways. KPT-9274 given orally at 150 mg/kg 5 days/week for 4 weeks dramatically reduced PNET sub-cutaneous tumor growth. Residual tumor analysis demonstrated target engagement in vivo and recapitulated in vitro results. Our investigations demonstrate that PAK4 and NAMPT are two viable therapeutic targets in the difficult to treat PNET that warrant further clinical investigation.
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http://dx.doi.org/10.3390/cancers11121902DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6966587PMC
November 2019

Pre-clinical anti-tumor activity of Bruton's Tyrosine Kinase inhibitor in Hodgkin's Lymphoma cellular and subcutaneous tumor model.

Heliyon 2019 Aug 31;5(8):e02290. Epub 2019 Aug 31.

Department of Medicine, University of Tennessee Knoxville, Knoxville Tennessee, USA.

Bruton's Tyrosine Kinase (BTK) is a member of the TEC family and plays a central role in B-cell signaling, activation, proliferation and differentiation. Here we evaluated the impact of BTK inhibitor Ibrutinib on a panel of HL models in vitro and in vivo. Ibrutinib suppressed viability and induced apoptosis in 4 HL cell lines in a dose and time dependent manner. Molecular analysis showed induction of both apoptotic and autophagy markers. Ibrutinib treatment resulted in suppression of BTK and other downstream targets including PI3K, mTOR and RICTOR. Ibrutinib given at 50 mg/kg p.o daily for three weeks caused statistically significant inhibition of HL cell line derived subcutaneous xenografts (p < 0.01) in ICR-SCID mice. Molecular analysis of residual tumor tissue revealed down-regulation of BTK; its related markers and autophagy markers. Our studies are the first showing in vitro and in vivo action of BTK inhibition in classical HL. A phase II study examining the activity of ibrutinib in relapsed or refractory HL is currently enrolling (NCT02824029).
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http://dx.doi.org/10.1016/j.heliyon.2019.e02290DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6726720PMC
August 2019

DNA-Methylation-Caused Downregulation of Contributes to the High Expression of XPO1 and the Aggressive Growth of Tumors in Pancreatic Ductal Adenocarcinoma.

Cancers (Basel) 2019 Aug 2;11(8). Epub 2019 Aug 2.

Department of Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA.

Pancreatic ductal adenocarcinoma is one of the most aggressive cancers, with high mortality in the United States. One of the important signal transduction proteins involved in the regulation of pancreatic cancer's aggressive progression is the nuclear export protein (XPO1). High expression of XPO1 has been found in pancreatic, lung, breast and other cancers and lymphomas with a poor prognosis of patients with tumors and high proliferative activity of cancer cells. Because XPO1 exports multiple tumor suppressor proteins simultaneously from the nucleus, the inhibition of XPO1 may retain multiple tumor suppressors in the nucleus, resulting in the suppression of cell proliferation and the induction of apoptosis in tumors. In this study, we found that the high expression of XPO1 in pancreatic cancer cells could be, in part, due to the methylation of the gene, leading to the low expression level of the family. By co-transfection of the XPO1 3'-UTR-Luc target vector with mimic, we found that XPO1 is a direct target of the family. We also observed that the enforced expression of the family inhibited the expression of XPO1, resulting in the suppression of pancreatic cancer growth both in vitro and in vivo. These findings could help to design a novel therapeutic strategy for the treatment of pancreatic cancer by introducing into cancer cells.
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http://dx.doi.org/10.3390/cancers11081101DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6721494PMC
August 2019

Evaluation of cationic channel TRPV2 as a novel biomarker and therapeutic target in Leukemia-Implications concerning the resolution of pulmonary inflammation.

Sci Rep 2019 02 7;9(1):1554. Epub 2019 Feb 7.

Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar.

Patients treated during leukemia face the risk of complications including pulmonary dysfunction that may result from infiltration of leukemic blast cells (LBCs) into lung parenchyma and interstitium. In LBCs, we demonstrated that transient receptor potential vanilloid type 2 channel (TRPV2), reputed for its role in inflammatory processes, exhibited oncogenic activity associated with alteration of its molecular expression profile. TRPV2 was overexpressed in LBCs compared to normal human peripheral blood mononuclear cells (PBMCs). Additionally, functional full length isoform and nonfunctional short form pore-less variant of TRPV2 protein were up-regulated and down-regulated respectively in LBCs. However, the opposite was found in PBMCs. TRPV2 silencing or pharmacological targeting by Tranilast (TL) or SKF96365 (SKF) triggered caspace-mediated apoptosis and cell cycle arrest. TL and SKF inhibited chemotactic peptide fMLP-induced response linked to TRPV2 Ca activity, and down-regulated expression of surface marker CD38 involved in leukemia and lung airway inflammation. Challenging lung airway epithelial cells (AECs) with LBCs decreased (by more than 50%) transepithelial resistance (TER) denoting barrier function alteration. Importantly, TL prevented such loss in TER. Therefore, TRPV2 merits further exploration as a pharmacodynamic biomarker for leukemia patients (with pulmonary inflammation) who might be suitable for a novel [adjuvant] therapeutic strategy based on TL.
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http://dx.doi.org/10.1038/s41598-018-37469-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6367460PMC
February 2019

Obesity-induced MBD2_v2 expression promotes tumor-initiating triple-negative breast cancer stem cells.

Mol Oncol 2019 04 1;13(4):894-908. Epub 2019 Mar 1.

Department of Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI, USA.

Obesity is a risk factor for triple-negative breast cancer (TNBC) incidence and poor outcomes, but the underlying molecular biology remains unknown. We previously identified in TNBC cell cultures that expression of epigenetic reader methyl-CpG-binding domain protein 2 (MBD2), specifically the alternative mRNA splicing variant MBD variant 2 (MBD2_v2), is dependent on reactive oxygen species (ROS) and is crucial for maintenance and expansion of cancer stem cell-like cells (CSCs). Because obesity is coupled with inflammation and ROS, we hypothesized that obesity can fuel an increase in MBD2_v2 expression to promote the tumor-initiating CSC phenotype in TNBC cells in vivo. Analysis of TNBC patient datasets revealed associations between high tumor MBD2_v2 expression and high relapse rates and high body mass index (BMI). Stable gene knockdown/overexpression methods were applied to TNBC cell lines to elucidate that MBD2_v2 expression is governed by ROS-dependent expression of serine- and arginine-rich splicing factor 2 (SRSF2). We employed a diet-induced obesity (DIO) mouse model that mimics human obesity to investigate whether obesity causes increased MBD2_v2 expression and increased tumor initiation capacity in inoculated TNBC cell lines. MBD2_v2 and SRSF2 levels were increased in TNBC cell line-derived tumors that formed more frequently in DIO mice relative to tumors in lean control mice. Stable MBD2_v2 overexpression increased the CSC fraction in culture and increased TNBC cell line tumor initiation capacity in vivo. SRSF2 knockdown resulted in decreased MBD2_v2 expression, decreased CSCs in TNBC cell cultures, and hindered tumor formation in vivo. This report describes evidence to support the conclusion that MBD2_v2 expression is induced by obesity and drives TNBC cell tumorigenicity, and thus provides molecular insights into support of the epidemiological evidence that obesity is a risk factor for TNBC. The majority of TNBC patients are obese and rising obesity rates threaten to further increase the burden of obesity-linked cancers, which reinforces the relevance of this report.
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http://dx.doi.org/10.1002/1878-0261.12444DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6441886PMC
April 2019

Anticancer Activity of Camel Milk via Induction of Autophagic Death in Human Colorectal and Breast Cancer Cells

Asian Pac J Cancer Prev 2018 Dec 25;19(12):3501-3509. Epub 2018 Dec 25.

Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, State of Qatar. Email:

Background/ Objective: Camel milk is traditionally known for its human health benefits and believed to be a remedy for various human ailments including cancer. The study was aimed to evaluate the inhibitory effects of commercially available camel milk on cancer cells and its underlying mechanism(s). Materials and Methods: Two cell lines: colorectal cancer HCT 116 and breast cancer MCF-7 were cultured with different doses of camel milk. The effects of camel milk on cell death were determined by MTT assay, viability by trypan blue exclusion assay and migration by in vitro scratch assay. The mechanism was elucidated by western blotting and confocal microscopy was used to confirm autophagy. Results: Camel milk significantly reduced proliferation, viability as well as migration of both the cells. The accumulation of LC3-II protein along with reduction in expression of p62 and Atg 5-12, the autophagy proteins implied induction of autophagy. The (GFP)-LC3 puncta detected by confocal microscopy confirmed the autophagosome formation in response to camel milk treatment. Conclusion: Camel milk exerted antiproliferative effects on human colorectal HCT 116 and breast MCF-7 cancer cells by inducing autophagy.
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http://dx.doi.org/10.31557/APJCP.2018.19.12.3501DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6428541PMC
December 2018

Comparison of 10 and 14 days of triple therapy versus 10 days of sequential therapy for Helicobacter pylori eradication: A prospective randomized study.

Turk J Gastroenterol 2018 09;29(5):549-554

Translational Research Institute, Hamad Medical Corporation, Doha, Qatar.

Background/aims: The aim of the present study was to compare between the efficacy and tolerability of a sequential therapy (ST) as the first-line treatment for adults with Helicobacter pylori infection and that of standard triple therapy (TT).

Materials And Methods: This was a prospective, randomized open-label, single-center study. We enrolled 206 patients who were divided into the following three treatment groups: Group A (pantoprazole 40 mg bid (twice daily), amoxicillin 1 g bid, and clarithromycin 500 mg bid for 10 d), Group B (the same TT as Group A for 14 d), and Group C (pantoprazole 40 mg bid and amoxicillin 1 g bid for 5 d, followed by pantoprazole 40 mg bid, clarithromycin 500 mg bid, and metronidazole 500 mg bid for additional 5 d).

Results: Intention-to-treat (ITT) analysis revealed that 14 d of TT achieved a higher eradication rate than 10 d of ST (54.8% vs. 50.7%), but the difference was not statistically significant (p=0.623); further, 10 d of TT achieved 45% eradication rate. Per-protocol (PP) analysis revealed that the success rate for 10 d of ST was more than that for 10 d of TT (70.6% vs. 65%; p=0.571); however, the success rate for 10 d of TT was not statistically different from that for 14 d of TT. The eradication rates achieved in the ITT analysis were lower than those achieved in the PP analysis for 10 (45% vs. 65%) or 14 (54.7% vs. 69%) d of TT or for 10 d of ST (50.7% vs. 70.6%). No statistically significant difference was observed. Adverse effects and compliance were not significantly different among the three groups.

Conclusion: Neither 10 d of ST nor 14 d of TT achieved the optimum H. pylori eradication rate.
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http://dx.doi.org/10.5152/tjg.2018.17707DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6284607PMC
September 2018

Nuclear Export Inhibition for Pancreatic Cancer Therapy.

Cancers (Basel) 2018 May 7;10(5). Epub 2018 May 7.

Department of Oncology, Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA.

Pancreatic cancer is a deadly disease that is resistant to most available therapeutics. Pancreatic cancer to date has no effective drugs that could enhance the survival of patients once their disease has metastasized. There is a need for the identification of novel actionable drug targets in this unusually recalcitrant cancer. Nuclear protein transport is an important mechanism that regulates the function of several tumor suppressor proteins (TSPs) in a compartmentalization-dependent manner. High expression of the nuclear exporter chromosome maintenance region 1 (CRM1) or exportin 1 (XPO1), a common feature of several cancers including pancreatic cancer, results in excessive export of critical TSPs to the incorrect cellular compartment, leading to their functional inactivation. Small molecule inhibitors of XPO1 can block this export, retaining very important and functional TSPs in the nucleus and leading to the effective killing of the cancer cells. This review highlights the current knowledge on the role of XPO1 in pancreatic cancer and how this serves as a unique and clinically viable target in this devastating and by far incurable cancer.
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http://dx.doi.org/10.3390/cancers10050138DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5977111PMC
May 2018

Exportin 1 (XPO1) inhibition leads to restoration of tumor suppressor miR-145 and consequent suppression of pancreatic cancer cell proliferation and migration.

Oncotarget 2017 Oct 17;8(47):82144-82155. Epub 2017 Jul 17.

Department of Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI, USA.

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer related deaths in the United States with a majority of these patients dying from aggressively invasive and metastatic disease. There is growing evidence that suggests an important role for microRNAs (miRNAs) in the pathobiology of aggressive PDAC. In this study, we found that the expression of miR-145 was significantly lower in PDAC cells when compared to normal pancreatic duct epithelial cells. Here we show that inhibition of the nuclear exporter protein exportin 1 (XPO1; also known as chromosome maintenance region 1 [CRM1]) by siRNA knockdown or by the Selective Inhibitor of Nuclear Export (SINE) compound (KPT-330; selinexor) increases miR-145 expression in PDAC cells resulting in the decreased cell proliferation and migration capacities. A similar result was obtained with forced expression of miR-145 in PDAC cells. To this end, SINE compound treatment mediated the down-regulation of known miR-145 targets genes including EGFR, MMP1, MT-MMP, c-Myc, Pak4 and Sox-2. In addition, selinexor induced the expression of two important tumor suppressive miRNAs miR-34c and let-7d leading to the up-regulation of p21. These results are the first to report that targeted inhibition of the nuclear export machinery could restore tumor suppressive miRNAs in PDAC that warrants further clinical investigations.
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http://dx.doi.org/10.18632/oncotarget.19285DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5669877PMC
October 2017

Dysregulated expression of SKP2 and its role in hematological malignancies.

Leuk Lymphoma 2018 05 10;59(5):1051-1063. Epub 2017 Aug 10.

a Translational Research Institute, Academic Health System , Hamad Medical Corporation , Doha , Qatar.

S-phase kinase-associated protein 2 (SKP2) is a well-studied F-box protein and a critical part of the Skp1-Cul1-Fbox (SCF) E3 ligase complex. It controls cell cycle by regulating the expression level of p27 and p21 through ubiquitination and proteasomal degradation. SKP2-mediated loss of p27Kip1 is associated with poor clinical outcome in various types of cancers including hematological malignancies. It is however well established that SKP2 is an oncogene, and its targeting may be an attractive therapeutic strategy for the management of hematological malignancies. In this article, we have highlighted the recent findings from our group and other investigators regarding the role of SKP2 in the pathogenesis of hematological malignancies.
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http://dx.doi.org/10.1080/10428194.2017.1359740DOI Listing
May 2018

Targeting of X-linked inhibitor of apoptosis protein and PI3-kinase/AKT signaling by embelin suppresses growth of leukemic cells.

PLoS One 2017 13;12(7):e0180895. Epub 2017 Jul 13.

Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, State of Qatar.

The X-linked inhibitor of apoptosis (XIAP) is a viable molecular target for anticancer drugs that overcome apoptosis-resistance of malignant cells. XIAP is an inhibitor of apoptosis, mediating through its association with BIR3 domain of caspase 9. Embelin, a quinone derivative isolated from the Embelia ribes plant, has been shown to exhibit chemopreventive, anti-inflammatory, and apoptotic activities via inhibiting XIAP activity. In this study, we found that embelin causes a dose-dependent suppression of proliferation in leukemic cell lines K562 and U937. Embelin mediated inhibition of proliferation correlates with induction of apoptosis. Furthermore, embelin treatment causes loss of mitochondrial membrane potential and release of cytochrome c, resulting in subsequent activation of caspase-3 followed by polyadenosin-5'-diphosphate-ribose polymerase (PARP) cleavage. In addition, embelin treatment of leukemic cells results in a decrease of constitutive phosphorylations/activation level of AKT and downregulation of XIAP. Gene silencing of XIAP and AKT expression showed a link between XIAP expression and activated AKT in leukemic cells. Interestingly, targeting of XIAP and PI3-kinase/AKT signaling augmented inhibition of proliferation and induction of apoptosis in leukemic cells. Altogether these findings raise the possibility that embelin alone or in combination with inhibitors of PI3-kinase/AKT pathway may have therapeutic usage in leukemia and possibly other malignancies with up-regulated XIAP pathway.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0180895PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5509148PMC
September 2017

Molecular genetic analysis of consanguineous families with primary microcephaly identified pathogenic variants in the ASPM gene.

J Genet 2017 Jun;96(2):383-387

Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha 3050, Qatar.

Autosomal recessive primary microcephaly is a rare genetic disorder that is characterized by reduced head circumference and a varying degree of intellectual disability. Genetic studies on consanguineous families with primary microcephaly have identified 15 (MCPH) causative genes that include MCPH1, WDR62, CDK5RAP2, CASC5, ASPM, CENPJ, STIL, CEP135, CEP152, ZNF335, PHC1, CDK6, CENPE, SASS6 MFSD2A ANKLE2 and CIT (Khan et al. 2014; Yamamoto et al. 2014; Alakbarzade et al. 2015;Morris-Rosendahl and Kaindl 2015; Basit et al. 2016). Physiologically, most of these MCPH proteins are involved in cell cycle and its regulation. In the present clinical genetic study, we have present two consanguineous Pakistani families segregating primary microcephaly and intellectual disability. These families were ascertained from the Saraiki ethnic part of Khyber-Pakhtunkhwa province in Pakistan. Whole exome sequencing in one family revealed a novel 1-bp deletion NM_018136.4: c.10013delA (p.Asp3338Valfs*2), while the other family showed a previously reported nonsense mutation NM_018136.4: c.9730C>T (rs199422195 (p.Arg3244*)) in ASPM gene. The novel frame-shift mutation (p.Asp3338Valfs*2) in ASPM presumably truncates the protein synthesis that results in loss of armadillo-type fold domain.
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http://dx.doi.org/10.1007/s12041-017-0759-xDOI Listing
June 2017

Targeting Rho GTPase effector p21 activated kinase 4 (PAK4) suppresses p-Bad-microRNA drug resistance axis leading to inhibition of pancreatic ductal adenocarcinoma proliferation.

Small GTPases 2019 09 23;10(5):367-377. Epub 2017 Jun 23.

a Department of Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine , Detroit , MI , USA.

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive and therapy resistant malignancy. Mutant K-Ras, found in >90% of refractory PDAC, acts as a molecular switch activating Rho GTPase signaling that in turn promotes a plethora of pro-survival molecules and oncogenic microRNAs. We investigated the impact of Rho GTPase effector protein p21 activated kinase 4 (PAK4) inhibition on pro-survival p-Bad and oncogenic miRNA signaling. We demonstrate that the dual NAMPT and PAK4 modulators (KPT-9274 and KPT-9307) inhibit PDAC cell proliferation through downregulation of Bad phosphorylation and upregulation of tumor suppressive miRNAs (miR-145, let-7c, let-7d, miR-34c, miR320 and miR-100). These results suggest that targeting PAK4 could become a promising approach to restore pro-apoptotic function of Bad and simultaneously activate tumor suppressive miRNAs in therapy resistant PDAC.
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http://dx.doi.org/10.1080/21541248.2017.1329694DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6748371PMC
September 2019

Anticancer potential of sanguinarine for various human malignancies.

Future Med Chem 2017 06 21;9(9):933-950. Epub 2017 Jun 21.

Translational Research Institute, Hamad Medical Corporation, Doha, Qatar.

Sanguinarine (Sang) - a benzophenanthridine alkaloid extracted from Sanguinaria canadensis - exhibits antioxidant, anti-inflammatory, proapoptotic and growth inhibitory activities on tumor cells of various cancer types as established by in vivo and in vitro studies. Although the underlying mechanism of Sang antitumor activity is yet to be fully elucidated, Sang has displayed multiple biological effects, which remain to suggest its possible use in plant-derived treatments of human malignancies. This review covers the anticancer abilities of Sang including inhibition of aberrantly activated signal transduction pathways, induction of cell death and inhibition of cancer cell proliferation. It also highlights Sang-mediated inhibition of angiogenesis, inducing the expression of tumor suppressors, sensitization of cancer cells to standard chemotherapeutics to enhance their cytotoxic effects, while addressing the present need for further pharmacokinetic-based studies.
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http://dx.doi.org/10.4155/fmc-2017-0041DOI Listing
June 2017

Targeting ERK enhances the cytotoxic effect of the novel PI3K and mTOR dual inhibitor VS-5584 in preclinical models of pancreatic cancer.

Oncotarget 2017 Jul;8(27):44295-44311

Department of Oncology, Wayne State University School of Medicine, Detroit, MI, USA.

Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease in urgent need of newer therapeutic modalities. Majority of patients with PDAC have mutations in KRAS, which unfortunately remains an ineffectual target. Our strategy here is to target KRAS downstream effectors PI3K and mTOR. In this study, we investigated the antitumor efficacy of the novel PI3K and mTOR dual inhibitor VS-5584 in PDAC. Our data shows that PI3K/mTOR dual inhibition causes ERK activation in all tested PDAC cell lines. Although the MEK inhibitor GSK1120212 could abrogate VS-5584-induced ERK activation, it did not substantially enhance cell death in all the cell lines tested. However, combination with ERK inhibitor SCH772984 not only mitigated VS-5584-induced ERK activation but also enhanced VS-5584-induced cell death. In a xenograft model of PDAC, we observed 28% and 44% tumor inhibition for individual treatment with VS-5584 and SCH772984, respectively, while the combined treatment showed superior tumor inhibition (80%) compared to vehicle control treatment. Our findings support the clinical development of VS-5584 and ERK inhibitor combination for PDAC treatment.
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http://dx.doi.org/10.18632/oncotarget.17869DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5546481PMC
July 2017

Potential therapeutic targets of Guggulsterone in cancer.

Nutr Metab (Lond) 2017 28;14:23. Epub 2017 Feb 28.

Translational Research Institute, Hamad Medical Corporation, PO Box 3050, Doha, Qatar.

Natural compounds capable of inducing apoptosis in cancer cells have always been of considerable interest as potential anti-cancer agents. Many such compounds are under screening and development with their potential evolution as a clinical drug benefiting many of the cancer patients. Guggulsterone (GS), a phytosterol isolated gum resin of the tree has been widely used in Indian traditional medicine as a remedy for various diseses. GS has been shown to possess cancer chemopreventive and therapeutic potential as established by in vitro and in vivo studies. GS has been shown to target constitutively activated survival pathways such as PI3-kinase/AKT, JAK/STAT, and NFκB signaling pathways that are involved in the regulation of growth and inflammatory responses regulation of antiapoptotic and inflammatory genes. The current review focuses on the molecular targets of GS, cellular responses, and the animal model studies in various cancers. The mechanistic action of GS in different types of cancers also forms a part of this review. The perspective of translating this natural compound into a clinically approved drug with its pros and cons is also discussed.
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http://dx.doi.org/10.1186/s12986-017-0180-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5331628PMC
February 2017

Targeting acute myeloid leukemia stem cell signaling by natural products.

Mol Cancer 2017 01 30;16(1):13. Epub 2017 Jan 30.

Translational Research Institute, Academic Health System, Hamad Medical Corporation, PO Box 3050, Doha, Qatar.

Acute myeloid leukemia (AML) is the most commonly diagnosed leukemia in adults (25%) and comprises 15-20% in children. It is a genetically heterogeneous aggressive disease characterized by the accumulation of somatically acquired genetic changes, altering self-renewal, proliferation, and differentiation of hematopoietic progenitor cells, resulting in uncontrolled clonal proliferation of malignant progenitor myeloid cells in the bone marrow, peripheral blood, and occasionally in other body tissues. Treatment with modern chemotherapy regimen (cytarabine and daunorubicin) usually achieves high remission rates, still majority of patients are found to relapse, resulting in only 40-45% overall 5 year survival in young patients and less than 10% in the elderly AML patients. The leukemia stem cells (LSCs) are characterized by their unlimited self-renewal, repopulating potential and long residence in a quiescent state of G/G phase. LSCs are considered to have a pivotal role in the relapse and refractory of AML. Therefore, new therapeutic strategies to target LSCs with limited toxicity towards the normal hematopoietic population is critical for the ultimate curing of AML. Ongoing research works with natural products like parthenolide (a natural plant extract derived compound) and its derivatives, that have the ability to target multiple pathways that regulate the self-renewal, growth and survival of LSCs point to ways for a possible complete remission in AML. In this review article, we will update and discuss various natural products that can target LSCs in AML.
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http://dx.doi.org/10.1186/s12943-016-0571-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5282735PMC
January 2017

Novel p21-Activated Kinase 4 (PAK4) Allosteric Modulators Overcome Drug Resistance and Stemness in Pancreatic Ductal Adenocarcinoma.

Mol Cancer Ther 2017 01 15;16(1):76-87. Epub 2016 Nov 15.

Department of Oncology, Wayne State University School of Medicine, Karmanos Cancer Institute, Detroit, Michigan.

The p21-activated kinase 4 (PAK4) is a key downstream effector of the Rho family GTPases and is found to be overexpressed in pancreatic ductal adenocarcinoma (PDAC) cells but not in normal human pancreatic ductal epithelia (HPDE). Gene copy number amplification studies in PDAC patient cohorts confirmed PAK4 amplification making it an attractive therapeutic target in PDAC. We investigated the antitumor activity of novel PAK4 allosteric modulators (PAM) on a panel of PDAC cell lines and chemotherapy-resistant flow-sorted PDAC cancer stem cells (CSC). The toxicity and efficacy of PAMs were evaluated in multiple subcutaneous mouse models of PDAC. PAMs (KPT-7523, KPT-7189, KPT-8752, KPT-9307, and KPT-9274) show antiproliferative activity in vitro against different PDAC cell lines while sparing normal HPDE. Cell growth inhibition was concurrent with apoptosis induction and suppression of colony formation in PDAC. PAMs inhibited proliferation and antiapoptotic signals downstream of PAK4. Co-immunoprecipitation experiments showed disruption of PAK4 complexes containing vimentin. PAMs disrupted CSC spheroid formation through suppression of PAK4. Moreover, PAMs synergize with gemcitabine and oxaliplatin in vitro KPT-9274, currently in a phase I clinical trial (clinicaltrials.gov; NCT02702492), possesses desirable pharmacokinetic properties and is well tolerated in mice with the absence of any signs of toxicity when 200 mg/kg daily is administered either intravenously or orally. KPT-9274 as a single agent showed remarkable antitumor activity in subcutaneous xenograft models of PDAC cell lines and CSCs. These proof-of-concept studies demonstrated the antiproliferative effects of novel PAMs in PDAC and warrant further clinical investigations. Mol Cancer Ther; 16(1); 76-87. ©2016 AACR.
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http://dx.doi.org/10.1158/1535-7163.MCT-16-0205DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5221563PMC
January 2017

Vascular Endothelial Growth Factor (VEGF) Signaling in Tumour Vascularization: Potential and Challenges.

Curr Vasc Pharmacol 2017 ;15(4):339-351

Translational Research Institute, Academic Health System, Hamad Medical Corporation, PO Box 3050, Doha. Qatar.

Angiogenesis is defined as the physiological process by which new blood vessels develop from pre-existing vessels; either by sprouting or intussusception. Inhibition of angiogenesis is one of the most encouraging strategies to manage the growth and metastasis of cancers. The functional and proliferative status of blood vessels is regulated by the balance between various key molecules that either stimulate or inhibit angiogenesis. During quiescence, the "angiogenic switch" is "off". However, during tumour development pro-angiogenic factors such as vascular endothelial growth factor (VEGF), basic and acidic fibroblast growth factor, tumour necrosis factor-α and interleukin-1 are pathologically enhanced. Persistent growth of tumour directed capillary networks creates a favourable microenvironment, promoting cancer growth, progression and metastasis. VEGF, particularly VEGF-A, is a key angiogenic factor. Targeting VEGF, its receptors and the downstream signaling cascade, is a viable strategy to prevent tumour growth and metastasis. The present review discusses the role of VEGF in tumour angiogenesis and the current understanding of anti-VEGF therapies as well as refractoriness of anti-angiogenesis cancer therapy.
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http://dx.doi.org/10.2174/1570161115666170105124038DOI Listing
April 2018

The Molecular Genetics of Autosomal Recessive Nonsyndromic Intellectual Disability: a Mutational Continuum and Future Recommendations.

Ann Hum Genet 2016 Nov;80(6):342-368

Genomic Core Facility, Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, 3050, Qatar.

Intellectual disability (ID) is a clinical manifestation of the central nervous system without any major dysmorphologies of the brain. Biologically it affects learning capabilities, memory, and cognitive functioning. The basic defining features of ID are characterized by IQ<70, age of onset before 18 years, and impairment of at least two of the adaptive skills. Clinically it is classified in a syndromic (with additional abnormalities) and a nonsyndromic form (with only cognitive impairment). The study of nonsyndromic intellectual disability (NSID) can best explain the pathophysiology of cognition, intelligence and memory. Genetic analysis in autosomal recessive nonsyndrmic ID (ARNSID) has mapped 51 disease loci, 34 of which have revealed their defective genes. These genes play diverse physiological roles in various molecular processes, including methylation, proteolysis, glycosylation, signal transduction, transcription regulation, lipid metabolism, ion homeostasis, tRNA modification, ubiquitination and neuromorphogenesis. High-density SNP array and whole exome sequencing has increased the pace of gene discoveries and many new mutations are being published every month. The lack of uniform criteria has assigned multiple identifiers (or accession numbers) to the same MRT locus (e.g. MRT7 and MRT22). Here in this review we describe the molecular genetics of ARNSID, prioritize the candidate genes in uncharacterized loci, and propose a new nomenclature to reorganize the mutation data that will avoid the confusion of assigning duplicate accession numbers to the same ID locus and to make the data manageable in the future as well.
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http://dx.doi.org/10.1111/ahg.12176DOI Listing
November 2016

Targeting Cancer at the Nuclear Pore.

J Clin Oncol 2016 12 23;34(34):4180-4182. Epub 2016 Oct 23.

Asfar S. Azmi and Ramzi M. Mohammad, Wayne State University School of Medicine, Detroit, MI.

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http://dx.doi.org/10.1200/JCO.2016.67.5637DOI Listing
December 2016

Anti-tumor activity of selective inhibitor of nuclear export (SINE) compounds, is enhanced in non-Hodgkin lymphoma through combination with mTOR inhibitor and dexamethasone.

Cancer Lett 2016 12 28;383(2):309-317. Epub 2016 Sep 28.

Department of Oncology, Wayne State University, USA. Electronic address:

In previous studies we demonstrated that targeting the nuclear exporter protein exportin-1 (CRM1/XPO1) by a selective inhibitor of nuclear export (SINE) compound is a viable therapeutic strategy against Non-Hodgkin Lymphoma (NHL). Our studies along with pre-clinical work from others led to the evaluation of the lead SINE compound, selinexor, in a phase 1 trial in patients with CLL or NHL (NCT02303392). Continuing our previous work, we studied combinations of selinexor-dexamethasone (DEX) and selinexor-everolimus (EVER) in NHL. Combination of selinexor with DEX or EVER resulted in enhanced cytotoxicity in WSU-DLCL2 and WSU-FSCCL cells which was consistent with enhanced apoptosis. Molecular analysis showed enhancement in the activation of apoptotic signaling and down-regulation of XPO1. This enhancement is consistent with the mechanism of action of these drugs in that both selinexor and DEX antagonize NF-κB (p65) and mTOR (EVER target) is an XPO1 cargo protein. SINE compounds, KPT-251 and KPT-276, showed activities similar to CHOP (cyclophosphamide-hydroxydaunorubicin-oncovin-prednisone) regimen in subcutaneous and disseminated NHL xenograft models in vivo. In both animal models the anti-lymphoma activity of selinexor is enhanced through combination with DEX or EVER. The in vivo activity of selinexor and related SINE compounds relative to 'standard of care' treatment is consistent with the objective responses observed in Phase I NHL patients treated with selinexor. Our pre-clinical data provide a rational basis for testing these combinations in Phase II NHL trials.
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http://dx.doi.org/10.1016/j.canlet.2016.09.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5584550PMC
December 2016

Selinexor, a Selective Inhibitor of Nuclear Export (SINE) compound, acts through NF-κB deactivation and combines with proteasome inhibitors to synergistically induce tumor cell death.

Oncotarget 2016 Nov;7(48):78883-78895

Karyopharm Therapeutics Inc., Newton, MA, 02459, USA.

The nuclear export protein, exportin-1 (XPO1/CRM1), is overexpressed in many cancers and correlates with poor prognosis. Selinexor, a first-in-class Selective Inhibitor of Nuclear Export (SINE) compound, binds covalently to XPO1 and blocks its function. Treatment of cancer cells with selinexor results in nuclear retention of major tumor suppressor proteins and cell cycle regulators, leading to growth arrest and apoptosis. Recently, we described the selection of SINE compound resistant cells and reported elevated expression of inflammation-related genes in these cells. Here, we demonstrated that NF-κB transcriptional activity is up-regulated in cells that are naturally resistant or have acquired resistance to SINE compounds. Resistance to SINE compounds was created by knockdown of the cellular NF-κB inhibitor, IκB-α. Combination treatment of selinexor with proteasome inhibitors decreased NF-κB activity, sensitized SINE compound resistant cells and showed synergistic cytotoxicity in vitro and in vivo. Furthermore, we showed that selinexor inhibited NF-κB activity by blocking phosphorylation of the IκB-α and the NF-κB p65 subunits, protecting IκB-α from proteasome degradation and trapping IκB-α in the nucleus to suppress NF-κB activity. Therefore, combination treatment of selinexor with a proteasome inhibitor may be beneficial to patients with resistance to either single-agent.
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http://dx.doi.org/10.18632/oncotarget.12428DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5346685PMC
November 2016

Cholesterol Depletion Alters Cardiomyocyte Subcellular Signaling and Increases Contractility.

PLoS One 2016 21;11(7):e0154151. Epub 2016 Jul 21.

Department of Physiology, Wayne State University School of Medicine, 1104 Elliman Bldg., 421 East Canfield, Detroit, MI 48201, United States of America.

Unlabelled: Membrane cholesterol levels play an important factor in regulating cell function. Sarcolemmal cholesterol is concentrated in lipid rafts and caveolae, which are flask-shaped invaginations of the plasma membrane. The scaffolding protein caveolin permits the enrichment of cholesterol in caveolae, and caveolin interactions with numerous proteins regulate their function. The purpose of this study was to determine whether acute reductions in cardiomyocyte cholesterol levels alter subcellular protein kinase activation, intracellular Ca2+ and contractility.

Methods: Ventricular myocytes, isolated from adult Sprague Dawley rats, were treated with the cholesterol reducing agent methyl-β-cyclodextrin (MβCD, 5 mM, 1 hr, room temperature). Total cellular cholesterol levels, caveolin-3 localization, subcellular, ERK and p38 mitogen activated protein kinase (MAPK) signaling, contractility, and [Ca2+]i were assessed.

Results: Treatment with MβCD reduced cholesterol levels by ~45 and shifted caveolin-3 from cytoskeleton and triton-insoluble fractions to the triton-soluble fraction, and increased ERK isoform phosphorylation in cytoskeletal, cytosolic, triton-soluble and triton-insoluble membrane fractions without altering their subcellular distributions. In contrast the primary effect of MβCD was on p38 subcellular distribution of p38α with little effect on p38 phosphorylation. Cholesterol depletion increased cardiomyocyte twitch amplitude and the rates of shortening and relaxation in conjunction with increased diastolic and systolic [Ca2+]i.

Conclusions: These results indicate that acute reductions in membrane cholesterol levels differentially modulate basal cardiomyocyte subcellular MAPK signaling, as well as increasing [Ca2+]i and contractility.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0154151PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4956108PMC
July 2017