Publications by authors named "Michal Kulinski"

20 Publications

  • Page 1 of 1

The metabolic footprint of compromised insulin sensitivity under fasting and hyperinsulinemic-euglycemic clamp conditions in an Arab population.

Sci Rep 2020 10 13;10(1):17164. Epub 2020 Oct 13.

Department of Internal Medicine, Qatar Metabolic Institute, Hamad Medical Corporation, Doha, Qatar.

Metabolic pathways that are corrupted at early stages of insulin resistance (IR) remain elusive. This study investigates changes in body metabolism in clinically healthy and otherwise asymptomatic subjects that may become apparent already under compromised insulin sensitivity (IS) and prior to IR. 47 clinically healthy Arab male subjects with a broad range of IS, determined by hyperinsulinemic-euglycemic clamp (HIEC), were investigated. Untargeted metabolomics and complex lipidomics were conducted on serum samples collected under fasting and HIEC conditions. Linear models were used to identify associations between metabolites concentrations and IS levels. Among 1896 identified metabolites, 551 showed significant differences between fasting and HIEC, reflecting the metabolic switch in energy utilization. At fasting, 336 metabolites, predominantly di- and tri-acylglycerols, showed significant differences between subjects with low and high levels of IS. Changes in amino acid, carbohydrate and fatty acid metabolism in response to insulin were impaired in subjects with low IS. Association of altered mannose and amino acids with IS was also replicated in an independent cohort of T2D patients. We identified metabolic phenotypes that characterize clinically healthy Arab subjects with low levels of IS at their fasting state. Our study is providing further insights into the metabolic pathways that precede IR.
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http://dx.doi.org/10.1038/s41598-020-73723-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7555540PMC
October 2020

Dysregulated Phosphorylation of p53, Autophagy and Stemness Attributes the Mutant p53 Harboring Colon Cancer Cells Impaired Sensitivity to Oxaliplatin.

Front Oncol 2020 28;10:1744. Epub 2020 Aug 28.

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

Colorectal cancer (CRC) forms one of the highest ranked cancer types in the world with its increasing incidence and mortality rates despite the advancement in cancer therapeutics. About 50% of human CRCs are reported to have defective p53 expression resultant of gene mutation often contributing to drug resistance. The current study was aimed to investigate the response of wild-type harboring HCT 116 and mutant harboring HT 29 colon cancer cells to chemotherapeutic drug oxaliplatin (OX) and to elucidate the underlying molecular mechanisms of sensitivity/resistance in correlation to their p53 status. OX inhibited growth of wild-type p53-harboring colon cancer cells via p53/p21-Bax mediated apoptosis. Our study revealed that dysregulated phosphorylation of p53, autophagy as well as cancer stemness attributes the mutant p53-harboring colon cancer cells impaired sensitivity to OX.
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http://dx.doi.org/10.3389/fonc.2020.01744DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7485421PMC
August 2020

Epigenetic and breast cancer therapy: Promising diagnostic and therapeutic applications.

Semin Cancer Biol 2020 Aug 25. Epub 2020 Aug 25.

Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, P.O. Box 3050, Qatar; Dermatology Institute, Academic Health System, Hamad Medical Corporation, Doha, P.O. Box 3050, Qatar. Electronic address:

The global burden of breast cancer (BC) is increasing significantly. This trend is caused by several factors such as late diagnosis, limited treatment options for certain BC subtypes, drug resistance which all lead to poor clinical outcomes. Recent research has reported the role of epigenetic alterations in the mechanism of BC pathogenesis and its hallmarks include drug resistance and stemness features. The understanding of these modifications and their significance in the management of BC carcinogenesis is challenging and requires further attention. Nevertheless, it promises to provide novel insight needed for utilizing these alterations as potential diagnostic, prognostic markers, predict treatment efficacy, as well as therapeutic agents. This highlights the importance of continuing research development to further advance the existing knowledge on epigenetics and BC carcinogenesis to overcome the current challenges. Hence, this review aims to shed light and discuss the current state of epigenetics research in the diagnosis and management of BC.
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http://dx.doi.org/10.1016/j.semcancer.2020.08.009DOI Listing
August 2020

Role of non-coding RNAs in the progression and resistance of cutaneous malignancies and autoimmune diseases.

Semin Cancer Biol 2020 Jul 25. Epub 2020 Jul 25.

Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar; Dermatology Institute, Academic Health System, Hamad Medical Corporation, Doha 3050, Qatar; Department of Dermatology and Venereology, Rumailah Hospital, Hamad Medical Corporation, Doha 3050, Qatar; Department of Medicine, Weill Cornell Medicine Qatar, Qatar Foundation-Education City, Doha 24144, Qatar; Department of Medicine, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA; College of Medicine, Qatar University, Doha 2713, Qatar.

Skin, the largest organ of human body, is vital for the existence and survival of human beings. Further, developmental and physiological mechanisms associated with cutaneous biology are vital for homeostasis as their deregulations converge towards pathogenesis of a number of skin diseases, including cancer. It has now been well accepted that most of the transcribed human genome lacks protein translational potential and has been termed as non-coding RNAs (nc-RNAs), which includes circular RNA (circRNA), small nuclear RNA (snRNA), small nucleolar RNA (snoRNA), micro RNA (miRNA), long noncoding RNA (lncRNA), and piwi-interacting RNA (piRNAs). These nc-RNAs have gained great attention in both preclinical and clinical research as they are critical in most of the regulatory mechanisms of biological homeostasis and disease development by controlling the gene expression at transcriptional, post-transcriptional and epigenetic level. In this review we have illustrated how nc-RNAs are critical in the development and maintenance of cutaneous homeostasis and functioning and also, most importantly, how the dysregulated expression and functioning of nc-RNAs play critical role in the pathogenesis of cutaneous diseases including cancer and the autoimmune skin diseases. Considering the vital role of nc-RNAs in cancer resistance, metastasis and autoimmune diseases, we have also highlighted their role as promising prognostic and therapeutic targets for the cutaneous diseases.
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http://dx.doi.org/10.1016/j.semcancer.2020.07.003DOI Listing
July 2020

Cytokine-Mediated Dysregulation of Signaling Pathways in the Pathogenesis of Multiple Myeloma.

Int J Mol Sci 2020 Jul 15;21(14). Epub 2020 Jul 15.

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

Multiple myeloma (MM) is a hematologic disorder of B lymphocytes characterized by the accumulation of malignant plasma cells (PCs) in the bone marrow. The altered plasma cells overproduce abnormal monoclonal immunoglobulins and also stimulate osteoclasts. The host's immune system and microenvironment are of paramount importance in the growth of PCs and, thus, in the pathogenesis of the disease. The interaction of MM cells with the bone marrow (BM) microenvironment through soluble factors and cell adhesion molecules causes pathogenesis of the disease through activation of multiple signaling pathways, including NF-κβ, PI3K/AKT and JAK/STAT. These activated pathways play a critical role in the inhibition of apoptosis, sustained proliferation, survival and migration of MM cells. Besides, these pathways also participate in developing resistance against the chemotherapeutic drugs in MM. The imbalance between inflammatory and anti-inflammatory cytokines in MM leads to an increased level of pro-inflammatory cytokines, which in turn play a significant role in dysregulation of signaling pathways and proliferation of MM cells; however, the association appears to be inadequate and needs more research. In this review, we are highlighting the recent findings on the roles of various cytokines and growth factors in the pathogenesis of MM and the potential therapeutic utility of aberrantly activated signaling pathways to manage the MM disease.
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http://dx.doi.org/10.3390/ijms21145002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7403981PMC
July 2020

Prevalence and Type Distribution of High-Risk Human Papillomavirus (HPV) in Breast Cancer: A Qatar Based Study.

Cancers (Basel) 2020 Jun 10;12(6). Epub 2020 Jun 10.

Breast Cancer Unit, Hamad General Hospital, Hamad Medical Corporation, Doha P.O. Box 3050, Qatar.

Human papillomavirus (HPV) has been implicated in the etiology of a variety of human cancers. Studies investigating the presence of high-risk (HR) HPV in breast tissue have generated considerable controversy over its role as a potential risk factor for breast cancer (BC). This is the first investigation reporting the prevalence and type distribution of high-risk HPV infection in breast tissue in the population of Qatar. A prospective comparison blind research study herein reconnoitered the presence of twelve HR-HPV types' DNA using multiplex PCR by screening a total of 150 fresh breast tissue specimens. Data obtained shows that HR-HPV types were found in 10% of subjects with breast cancer; of which the presence of HPV was confirmed in 4/33 (12.12%) of invasive carcinomas. These findings, the first reported from the population of Qatar, suggest that the selective presence of HPV in breast tissue is likely to be a related factor in the progression of certain cases of breast cancer.
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http://dx.doi.org/10.3390/cancers12061528DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7352582PMC
June 2020

Loss of the Fanconi anemia-associated protein NIPA causes bone marrow failure.

J Clin Invest 2020 06;130(6):2827-2844

Department of Internal Medicine I, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.

Inherited bone marrow failure syndromes (IBMFSs) are a heterogeneous group of disorders characterized by defective hematopoiesis, impaired stem cell function, and cancer susceptibility. Diagnosis of IBMFS presents a major challenge due to the large variety of associated phenotypes, and novel, clinically relevant biomarkers are urgently needed. Our study identified nuclear interaction partner of ALK (NIPA) as an IBMFS gene, as it is significantly downregulated in a distinct subset of myelodysplastic syndrome-type (MDS-type) refractory cytopenia in children. Mechanistically, we showed that NIPA is major player in the Fanconi anemia (FA) pathway, which binds FANCD2 and regulates its nuclear abundance, making it essential for a functional DNA repair/FA/BRCA pathway. In a knockout mouse model, Nipa deficiency led to major cell-intrinsic defects, including a premature aging phenotype, with accumulation of DNA damage in hematopoietic stem cells (HSCs). Induction of replication stress triggered a reduction in and functional decline of murine HSCs, resulting in complete bone marrow failure and death of the knockout mice with 100% penetrance. Taken together, the results of our study add NIPA to the short list of FA-associated proteins, thereby highlighting its potential as a diagnostic marker and/or possible target in diseases characterized by hematopoietic failure.
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http://dx.doi.org/10.1172/JCI126215DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7260023PMC
June 2020

Role of non-coding RNA networks in leukemia progression, metastasis and drug resistance.

Mol Cancer 2020 03 12;19(1):57. Epub 2020 Mar 12.

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

Early-stage detection of leukemia is a critical determinant for successful treatment of the disease and can increase the survival rate of leukemia patients. The factors limiting the current screening approaches to leukemia include low sensitivity and specificity, high costs, and a low participation rate. An approach based on novel and innovative biomarkers with high accuracy from peripheral blood offers a comfortable and appealing alternative to patients, potentially leading to a higher participation rate.Recently, non-coding RNAs due to their involvement in vital oncogenic processes such as differentiation, proliferation, migration, angiogenesis and apoptosis have attracted much attention as potential diagnostic and prognostic biomarkers in leukemia. Emerging lines of evidence have shown that the mutational spectrum and dysregulated expression of non-coding RNA genes are closely associated with the development and progression of various cancers, including leukemia. In this review, we highlight the expression and functional roles of different types of non-coding RNAs in leukemia and discuss their potential clinical applications as diagnostic or prognostic biomarkers and therapeutic targets.
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http://dx.doi.org/10.1186/s12943-020-01175-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7069174PMC
March 2020

Non-Coding RNAs as Regulators and Markers for Targeting of Breast Cancer and Cancer Stem Cells.

Cancers (Basel) 2020 Feb 4;12(2). Epub 2020 Feb 4.

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

Breast cancer is regarded as a heterogeneous and complicated disease that remains the prime focus in the domain of public health concern. Next-generation sequencing technologies provided a new perspective dimension to non-coding RNAs, which were initially considered to be transcriptional noise or a product generated from erroneous transcription. Even though understanding of biological and molecular functions of noncoding RNA remains enigmatic, researchers have established the pivotal role of these RNAs in governing a plethora of biological phenomena that includes cancer-associated cellular processes such as proliferation, invasion, migration, apoptosis, and stemness. In addition to this, the transmission of microRNAs and long non-coding RNAs was identified as a source of communication to breast cancer cells either locally or systemically. The present review provides in-depth information with an aim at discovering the fundamental potential of non-coding RNAs, by providing knowledge of biogenesis and functional roles of micro RNA and long non-coding RNAs in breast cancer and breast cancer stem cells, as either oncogenic drivers or tumor suppressors. Furthermore, non-coding RNAs and their potential role as diagnostic and therapeutic moieties have also been summarized.
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http://dx.doi.org/10.3390/cancers12020351DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7072613PMC
February 2020

Curcumin-Mediated Apoptotic Cell Death in Papillary Thyroid Cancer and Cancer Stem-Like Cells through Targeting of the JAK/STAT3 Signaling Pathway.

Int J Mol Sci 2020 Jan 9;21(2). Epub 2020 Jan 9.

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

The constitutive activation of Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) signal transduction is well elucidated in STAT3-mediated oncogenesis related to thyroid cancer and is considered to be a plausible therapeutic target. Hence, we investigated whether curcumin, a natural compound, can target the JAK/STAT3 signaling pathway to induce cytotoxic effects in papillary thyroid cancer (PTC) cell lines (BCPAP and TPC-1) and derived thyroid cancer stem-like cells (thyrospheres). Curcumin suppressed PTC cell survival in a dose-dependent manner via the induction of caspase-mediated apoptosis and caused the attenuation of constitutively active STAT3 (the dephosphorylation of Tyr705-STAT3) without affecting STAT3. Gene silencing with STAT3-specific siRNA showed the modulation of genes associated with cell growth and proliferation. The cotreatment of PTC cell lines with curcumin and cisplatin synergistically potentiated cytotoxic effects via the suppression of JAK/STAT3 activity along with the inhibition of antiapoptotic genes and the induction of proapoptotic genes, and it also suppressed the migration of PTC cells by downregulating matrix metalloproteinases and the inhibition of colony formation. Finally, thyrospheres treated with curcumin and cisplatin showed suppressed STAT3 phosphorylation, a reduced formation of thyrospheres, and the downregulated expression of stemness markers, in addition to apoptosis. The current study's findings suggest that curcumin synergistically enhances the anticancer activity of cisplatin in PTC cells as well as in cancer stem-like cells by targeting STAT3, which suggests that curcumin combined with chemotherapeutic agents may provide better therapeutic outcomes.
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http://dx.doi.org/10.3390/ijms21020438DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7014270PMC
January 2020

Protein Expression Profiling Identifies Key Proteins and Pathways Involved in Growth Inhibitory Effects Exerted by Guggulsterone in Human Colorectal Cancer Cells.

Cancers (Basel) 2019 Oct 1;11(10). Epub 2019 Oct 1.

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

Colorectal cancer (CRC) is a leading killer cancer worldwide and one of the most common malignancies with increasing incidences of mortality. Guggulsterone (GS) is a plant sterol used for treatment of various ailments such as obesity, hyperlipidemia, diabetes, and arthritis. In the current study, anti-cancer effects of GS in human colorectal cancer cell line HCT 116 was tested, potential targets identified using mass spectrometry-based label-free shotgun proteomics approach and key pathways validated by proteome profiler antibody arrays. Comprehensive proteomic profiling identified 14 proteins as significantly dysregulated. Proteins involved in cell proliferation/migration, tumorigenesis, cell growth, metabolism, and DNA replication were downregulated while the protein with functional role in exocytosis/tumor suppression was found to be upregulated. Our study evidenced that GS treatment altered expression of Bcl-2 mediated the mitochondrial release of cytochrome c which triggered the formation of apoptosome as well as activation of caspase-3/7 leading to death of HCT 116 cells via intrinsic apoptosis pathway. GS treatment also induced expression of p53 protein while p21 expression was unaltered with no cell cycle arrest. In addition, GS was found to inhibit NF-kB signaling in colon cancer cells by quelling the expression of its regulated gene products Bcl-2, cIAP-1, and survivin.
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http://dx.doi.org/10.3390/cancers11101478DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6826505PMC
October 2019

Metabolomics of Dynamic Changes in Insulin Resistance Before and After Exercise in PCOS.

Front Endocrinol (Lausanne) 2019 27;10:116. Epub 2019 Feb 27.

Weill Cornell Medicine-Qatar, Doha, Qatar.

Plasma elevated levels of branched chain amino acids (BCAA) and aromatic amino acids (AAA) have been associated with obesity and insulin resistance, but their relationship to stimulated insulin resistance (IR) in PCOS and in response to exercise is unknown. Indeed, it is unknown whether the mechanism of IR in PCOS is mediated through changes in the metabolome. Twelve women with polycystic ovary syndrome (PCOS) and ten age and body mass index matched controls completed an 8 week supervised exercise program at 60% maximal oxygen consumption. Before and after the exercise program, all participants underwent maximal IR stimulation with intralipid infusions followed by insulin sensitivity (IS) measurement by hyperinsulinaemic euglycaemic clamps. Amino acid profiles and metabolites were taken at baseline and at maximal insulin resistance stimulation before and after the exercise program. At baseline, PCOS subjects showed increased leucine/isoleucine, glutamate, methionine, ornithine, phenylalanine, tyrosine and proline ( < 0.05) that, following exercise, did not differ from controls. While compering within the groups, no significant changes in the amino acid levels before and after exercise were observed. Exercise improved VO2 max ( < 0.01) but did not alter weight. Amino acid profiles were unaffected by an acute increase in IR induced by the lipid infusion. IS was lower in PCOS ( < 0.001) and was further decreased by the lipid infusion in both PCOS and controls. Although, exercise improved IS in both PCOS and in controls, the IS remained compromised in PCOS. The baseline amino acid profile in PCOS reflected that seen in obese subjects and differed to controls. After exercise, and despite no change in weight in either group, there were no differences in the amino acid profile between PCOS and controls. This shows that exercise may normalize the amino acid metabolome, irrespective of weight. : ISRCTN42448814.
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http://dx.doi.org/10.3389/fendo.2019.00116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6400834PMC
February 2019

Accelerated lipid catabolism and autophagy are cancer survival mechanisms under inhibited glutaminolysis.

Cancer Lett 2018 08 17;430:133-147. Epub 2018 May 17.

Department of Physiology and Biophysics, Weill Cornell Medicine - Qatar, Education City, PO 24144, Doha, Qatar. Electronic address:

Suppressing glutaminolysis does not always induce cancer cell death in glutamine dependent tumors because cells may switch to alternative energy sources. To reveal compensatory metabolic pathways, we investigated the metabolome-wide cellular response to inhibited glutaminolysis in cancer cells. Glutaminolysis inhibition with C.968 suppressed cell proliferation but was insufficient to induce cancer cell death. We found that lipid catabolism was activated as a compensation for glutaminolysis inhibition. Accelerated lipid catabolism, together with oxidative stress induced by glutaminolysis inhibition, triggered autophagy. Simultaneously inhibiting glutaminolysis and either beta oxidation with trimetazidine or autophagy with chloroquine both induced cancer cell death. Here we identified metabolic escape mechanisms contributing to cancer cell survival under treatment and we suggest potentially translational strategy for combined cancer therapy, given that chloroquine is an FDA approved drug. Our findings are first to show efficiency of combined inhibition of glutaminolysis and beta oxidation as potential anti-cancer strategy as well as add to the evidence that combined inhibition of glutaminolysis and autophagy may be effective in glutamine-addicted cancers.
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http://dx.doi.org/10.1016/j.canlet.2018.05.017DOI Listing
August 2018

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

Measurement of 1,5-anhydroglucitol in blood and saliva: from non-targeted metabolomics to biochemical assay.

J Transl Med 2016 05 18;14(1):140. Epub 2016 May 18.

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

Background: Diabetes testing using saliva, rather than blood and urine, could facilitate diabetes screening in public spaces. We previously identified 1,5-anhydro-D-glucitol (1,5-AG) in saliva as a diabetes biomarker. The Glycomark™ assay kit is FDA approved for 1,5-AG measurement in blood. Here we evaluated its applicability for 1,5-AG quantification in saliva.

Methods: Using pooled saliva samples, we validated Glycomark™ assay use with a RX Daytona(+) clinical chemistry analyser. We then used this set-up to analyse 82 paired blood and saliva samples from a diabetes case-control study, for which broad mass spectrometry-based characterization of the blood and saliva metabolome was also available. Osmolality was measured to account for potential variability in saliva samples.

Results: The technical variability of the read-outs for the pooled saliva samples (CV = 2.05 %) was comparable to that obtained with manufacturer-provided blood surrogate quality controls (CV = 1.38-1.8 %). We found a high correlation between Glycomark assay and mass spectrometry measurements of serum 1,5-AG (r(2) = 0.902), showing reproducibility of the non-targeted metabolomics results. The significant correlation between the osmolality measurements performed at two independent platforms with the time interval of 2 years (r(2) = 0.887), also indicates the sample integrity. The assay read-out for saliva was not correlated with the mass spectrometry-based 1,5-AG saliva measurements. Comparison with the full saliva metabolome revealed a high correlation of the saliva assay read-outs with galactose.

Conclusions: Glycomark™ assay read-outs for saliva were stable and replicable. However, the signal was dominated by galactose, which is biochemically similar to 1,5-AG and absent in blood. Adapting the 1,5-AG kit for saliva analysis will require enzymatic depletion of galactose. This should be feasible, since the assay already includes a similar step for glucose depletion from blood samples.
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http://dx.doi.org/10.1186/s12967-016-0897-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4870767PMC
May 2016

Bortezomib-mediated downregulation of S-phase kinase protein-2 (SKP2) causes apoptotic cell death in chronic myelogenous leukemia cells.

J Transl Med 2016 Mar 9;14:69. Epub 2016 Mar 9.

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

Background: Proteasome inhibitors are attractive cancer therapeutic agents because they can regulate apoptosis-related proteins. Bortezomib also known as Velcade(®), a proteasome inhibitor that has been approved by the food and drug administration for treatment of patients with multiple myeloma, and many clinical trials are ongoing to examine to the efficacy of bortezomib for the treatment of other malignancies. Bortezomib has been shown to induce apoptosis and inhibit cell growth of many cancer cells. In current study, we determine whether bortezomib induces cell death/apoptosis in CML.

Methods: Cell viability was measured using MTT assays. Apoptosis was measured by annexin V/PI dual staining and DNA fragmentation assays. Immunoblotting was performed to examine the expression of proteins. Colony assays were performed using methylcellulose.

Results: Treatment of CML cells with bortezomib results in downregulation of S-phase kinase protein 2 (SKP2) and concomitant stabilization of the expression of p27Kip1. Furthermore, knockdown of SKP2 with small interference RNA specific for SKP2 caused accumulation of p27Kip1. CML cells exposed to bortezomib leads to conformational changes in Bax protein, resulting in loss of mitochondrial membrane potential and leakage of cytochrome c to the cytosol. In the cytosol, cytochrome c causes sequential activation of caspase-9, caspase-3, PARP cleavage and apoptosis. Pretreatment of CML cells with a universal inhibitor of caspases, z-VAD-fmk, prevents bortezomib-mediated apoptosis. Our data also demonstrated that bortezomib treatment of CML downregulates the expression of inhibitor of apoptosis proteins. Finally, inhibition of proteasome pathways by bortezomib suppresses colony formation ability of CML cells.

Conclusions: Altogether, these findings suggest that bortezomib suppresses the cell proliferation via induction of apoptosis in CML cells by downregulation of SKP2 with concomitant accumulation of p27Kip1, suggesting that proteasomal pathway may form novel therapeutic targets for better management of CML.
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http://dx.doi.org/10.1186/s12967-016-0823-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4784454PMC
March 2016

Involvement of F-BOX proteins in progression and development of human malignancies.

Semin Cancer Biol 2016 Feb 26;36:18-32. Epub 2015 Sep 26.

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

The Ubiquitin Proteasome System (UPS) is a core regulator with various protein components (ubiquitin-activating E1 enzymes, ubiquitin-conjugating E2 enzymes, ubiquitin-protein E3 ligases, and the 26S proteasome) which work together in a coordinated fashion to ensure the appropriate and efficient proteolysis of target substrates. E3 ubiquitin ligases are essential components of the UPS machinery, working with E1 and E2 enzymes to bind substrates and assist the transport of ubiquitin molecules onto the target protein. As the UPS controls the degradation of several oncogenes and tumor suppressors, dysregulation of this pathway leads to several human malignancies. A major category of E3 Ub ligases, the SCF (Skp-Cullin-F-box) complex, is composed of four principal components: Skp1, Cul1/Cdc53, Roc1/Rbx1/Hrt1, and an F-box protein (FBP). FBPs are the substrate recognition components of SCF complexes and function as adaptors that bring substrates into physical proximity with the rest of the SCF. Besides acting as a component of SCF complexes, FBPs are involved in DNA replication, transcription, cell differentiation and cell death. This review will highlight the recent literature on three well characterized FBPs SKP2, Fbw7, and beta-TRCP. In particular, we will focus on the involvement of these deregulated FBPs in the progression and development of various human cancers. We will also highlight some novel substrates recently identified for these FBPs.
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http://dx.doi.org/10.1016/j.semcancer.2015.09.008DOI Listing
February 2016

Polymer-based non-viral gene delivery as a concept for the treatment of cancer.

Pharmacol Rep 2009 Nov-Dec;61(6):993-9

Department of Bioorganic Chemistry, Wrocław University of Technology, Wybrzeze Wyspiańskiego 27, PL 50-370 Wrocław, Poland.

Gene therapy has become a promising technique for the treatment of cancer. Nevertheless, the success of gene therapy depends on the effectiveness of the vector. The challenge of a gene carrier is to deliver exogenous DNA from the site of administration into the nucleus of the appropriate target cell. Polymer-based vectors are biologically safe, have low production costs and are efficient tools for gene therapy. Although non-degradable polyplexes exhibit high gene expression levels, their application potential is limited due to their inability to be effectively eliminated, which results in cytotoxicity. The development of biodegradable polymers has allowed for high levels of transfection without cytotoxicity. For site-specific targeting of polyplexes, further modifications, such as incorporation of ligands, can be performed. Most expectations have been addressed to polyplexes architecture according it dynamic response with the microenvironment.
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http://dx.doi.org/10.1016/s1734-1140(09)70160-4DOI Listing
March 2010