Publications by authors named "Mohammed L Abba"

11 Publications

  • Page 1 of 1

Inhibitor of DNA binding proteins: implications in human cancer progression and metastasis.

Am J Transl Res 2018 15;10(12):3887-3910. Epub 2018 Dec 15.

Department of Hematology and Oncology, University Hospital Mannheim, Medical Faculty Mannheim, University of Heidelberg Mannheim, Germany.

Inhibitor of DNA binding (ID) proteins are a class of helix-loop-helix (HLH) transcription regulatory factors that act as dominant-negative antagonists of other basic HLH proteins through the formation of non-functional heterodimers. These proteins have been shown to play critical roles in a wide range of tumor-associated processes, including cell differentiation, cell cycle progression, migration and invasion, epithelial-mesenchymal transition, angiogenesis, stemness, chemoresistance, tumorigenesis, and metastasis. The aberrant expression of ID proteins has not only been detected in many types of human cancers, but is also associated with advanced tumor stages and poor clinical outcome. In this review, we provide an overview of the key biological functions of ID proteins including affiliated signaling pathways. We also describe the regulation of ID proteins in cancer progression and metastasis, and elaborate on expression profiles in cancer and the implications for prognosis. Lastly, we outline strategies for the therapeutic targeting of ID proteins as a promising and effective approach for anticancer therapy.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6325517PMC
December 2018

Whole genome sequencing puts forward hypotheses on metastasis evolution and therapy in colorectal cancer.

Nat Commun 2018 11 14;9(1):4782. Epub 2018 Nov 14.

Department of Experimental Surgery-Cancer Metastasis, Medical Faculty Mannheim, Ruprecht Karls University Heidelberg, 69120 Mannheim, Germany.

Incomplete understanding of the metastatic process hinders personalized therapy. Here we report the most comprehensive whole-genome study of colorectal metastases vs. matched primary tumors. 65% of somatic mutations originate from a common progenitor, with 15% being tumor- and 19% metastasis-specific, implicating a higher mutation rate in metastases. Tumor- and metastasis-specific mutations harbor elevated levels of BRCAness. We confirm multistage progression with new components ARHGEF7/ARHGEF33. Recurrently mutated non-coding elements include ncRNAs RP11-594N15.3, AC010091, SNHG14, 3' UTRs of FOXP2, DACH2, TRPM3, XKR4, ANO5, CBL, CBLB, the latter four potentially dual protagonists in metastasis and efferocytosis-/PD-L1 mediated immunosuppression. Actionable metastasis-specific lesions include FAT1, FGF1, BRCA2, KDR, and AKT2-, AKT3-, and PDGFRA-3' UTRs. Metastasis specific mutations are enriched in PI3K-Akt signaling, cell adhesion, ECM and hepatic stellate activation genes, suggesting genetic programs for site-specific colonization. Our results put forward hypotheses on tumor and metastasis evolution, and evidence for metastasis-specific events relevant for personalized therapy.
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http://dx.doi.org/10.1038/s41467-018-07041-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6235880PMC
November 2018

Prevention of carcinogenesis and metastasis by Artemisinin-type drugs.

Cancer Lett 2018 08 8;429:11-18. Epub 2018 May 8.

Department of Experimental Surgery - Cancer Metastasis, Medical Faculty Mannheim, Center for Biomedicine and Medical Technology Mannheim (CBTM), Ludolf-Krehl-Str. 6, 68135 Mannheim, Ruprecht-Karls University of Heidelberg, Germany. Electronic address:

Artemisia annua (sweet wormwood, qinhao) is an ancient Chinese herbal remedy for pyrexia. Nowadays, artemisinin (qinghaosu) and its derivatives belong to the standard therapies against malaria worldwide, and its discovery has led to the Nobel Prize in Physiology and Medicine to Youyou Tu in 2015. While most attention has been paid to the treatment of malaria, there is increasing evidence that Artemisinin-type drugs bear a considerable potential to treat and prevent cancer. Rather than reporting on therapy of cancer, this review gives a comprehensive and timely overview on the chemopreventive effects of artemisinin and its derivatives against carcinogenesis and metastasis formation, following the multistage model of carcinogenesis (initiation, promotion, progression). The favorable toxicity profile known from malaria studies indicates that artemisinin-type drugs may be safely applied to prevent carcinogenesis and cancer metastasis in human beings.
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http://dx.doi.org/10.1016/j.canlet.2018.05.008DOI Listing
August 2018

What is the optimal radiation dose for non-operable esophageal cancer? Dissecting the evidence in a meta-analysis.

Oncotarget 2017 Oct 28;8(51):89095-89107. Epub 2017 Jun 28.

Department of Radiotherapy, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China.

The standard radiation dose 50.4 Gy with concurrent chemotherapy for localized inoperable esophageal cancer as supported by INT-0123 trail is now being challenged since a radiation dose above 50 Gy has been successfully administered with an observable dose-response relationship and insignificant untoward effects. Therefore, to ascertain the treatment benefits of different radiation doses, we performed a meta-analysis with 18 relative publications. According to our findings, a dose between 50 and 70 Gy appears optimal and patients who received ≥ 60 Gy radiation had a significantly better prognosis (pooled HR = 0.78, = 0.004) as compared with < 60 Gy, especially in Asian countries (pooled HR = 0.75, = 0.003). However, contradictory results of treatment benefit for ≥ 60 Gy were observed in two studies from Western countries, and the pooled treatment benefit of ≥ 60 Gy radiation was inconclusive (pooled HR = 0.86, = 0.64). There was a marginal benefit in locoregional control in those treated with high dose (> 50.4/51 Gy) radiation when compared with those treated with low dose (≤ 50.4/51 Gy) radiation (pooled OR = 0.71, = 0.06). Patients that received ≥ 60 Gy radiation had better locoregional control (OR = 0.29, = 0.001), and for distant metastasis control, neither the > 50.4 Gy nor the ≥ 60 Gy treated group had any treatment benefit as compared to the groups that received ≤ 50.4 Gy and < 60 Gy group respectively. Taken together, a dose range of 50 to 70 Gy radiation with CCRT is recommended for non-operable EC patients. A dose of ≥ 60 Gy appears to be better in improving overall survival and locoregional control, especially in Asian countries, while the benefit of ≥ 60 Gy radiation in Western countries still remains controversial.
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http://dx.doi.org/10.18632/oncotarget.18760DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5687672PMC
October 2017

The role of microRNAs in photodynamic therapy of cancer.

Eur J Med Chem 2017 Dec 5;142:550-555. Epub 2017 Oct 5.

Cancer Biology and Genetics Laboratory, Centre of Excellence for Advanced Sciences, National Research Centre, Dokki, Cairo, Egypt; Biochemistry Department, National Research Centre, Dokki, Cairo, Egypt.

Photodynamic therapy (PDT) is a non-invasive treatment modality used in the management of both benign and malignant conditions. It involves the administration of a photosensitizing agent followed by local light irradiation, which activates the photosensitizer, resulting in tissue damage. An in-depth understanding of the molecular mechanisms and mediators of PDT is important, not only for appreciating how this treatment modality is effective, but also as an avenue for understanding potential shortfalls and untoward effects that can be managed or improved. MicroRNAs are a group of endogenous small non-coding regulatory molecules that play important roles in regulating several physiological processes and have been implicated in several pathologies including cancer. They have been found to regulate key cellular pathways and their aberrant expression highlights not only disease onset or progression, but is associated with therapy resistance and disease outcome. In the present review, we evaluate the role of microRNAs in PDT and dissect their function as effectors of PDT including the molecules they regulate. We also look at how miRNA signatures can be used as predictors of therapy response to PDT and what implications this may have in the treatment of patients with PDT.
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http://dx.doi.org/10.1016/j.ejmech.2017.10.011DOI Listing
December 2017

P53-induced miR-30e-5p inhibits colorectal cancer invasion and metastasis by targeting ITGA6 and ITGB1.

Int J Cancer 2017 11 24;141(9):1879-1890. Epub 2017 Jul 24.

Department of Experimental Surgery-Cancer Metastasis, Medical Faculty Mannheim, University of Heidelberg, Germany.

The tumor suppressor P53 is a critical regulator of normal cellular homeostasis whose function is either distorted or lost in several cancer types including colorectal cancer (CRC). A small group of microRNAs have come to be recognized as essential mediators of P53 function. In a genome-wide systematic approach, we explored miRNAs that are substantially altered by P53 loss and found miR-30e to be the most significantly deregulated miRNA in P53-knockout human CRC cells. We identified miR-30e-5p to be a novel direct transcriptional target of P53 with gain and loss of function experiments revealing miR-30e-5p to be a significant regulator of tumor cell migration, invasion and in vivo metastasis mediated in part by integrins alpha-6 and beta-1 as novel targets. MiR-30e-5p also significantly reduced tumor cell proliferation by causing G1/S cell cycle arrest, which was achieved by inducing P21 and P27 expression. Finally, we found miR-30e-5p to be lost in resected CRC tumors as compared to normal colon tissues. Taken together, miR-30e-5p is a novel effector of P53-induced suppression of migration, invasion and metastasis.
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http://dx.doi.org/10.1002/ijc.30854DOI Listing
November 2017

Systematic biobanking, novel imaging techniques, and advanced molecular analysis for precise tumor diagnosis and therapy: The Polish MOBIT project.

Adv Med Sci 2017 Sep 21;62(2):405-413. Epub 2017 Jun 21.

Indivumed GmbH, Falkenreid 88, Hamburg, Germany.

Personalized and precision medicine is gaining recognition due to the limitations by standard diagnosis and treatment; many areas of medicine, from cancer to psychiatry, are moving towards tailored and individualized treatment for patients based on their clinical characteristics and genetic signatures as well as novel imaging techniques. Advances in whole genome sequencing have led to identification of genes involved in a variety of diseases. Moreover, biomarkers indicating severity of disease or susceptibility to treatment are increasingly being characterized. The continued identification of new genes and biomarkers specific to disease subtypes and individual patients is essential and inevitable for translation into personalized medicine, in estimating both, disease risk and response to therapy. Taking into consideration the mostly unsolved necessity of tailored therapy in oncology the innovative project MOBIT (molecular biomarkers for individualized therapy) was designed. The aims of the project are: (i) establishing integrative management of precise tumor diagnosis and therapy including systematic biobanking, novel imaging techniques, and advanced molecular analysis by collecting comprehensive tumor tissues, liquid biopsies (whole blood, serum, plasma), and urine specimens (supernatant; sediment) as well as (ii) developing personalized lung cancer diagnostics based on tumor heterogeneity and integrated genomics, transcriptomics, metabolomics, and radiomics PET/MRI analysis. It will consist of 5 work packages. In this paper the rationale of the Polish MOBIT project as well as its design is presented. (iii) The project is to draw interest in and to invite national and international, private and public, preclinical and clinical initiatives to establish individualized and precise procedures for integrating novel targeted therapies and advanced imaging techniques.
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http://dx.doi.org/10.1016/j.advms.2017.05.002DOI Listing
September 2017

Two wavelength-shifting molecular beacons for simultaneous and selective imaging of vesicular miRNA-21 and miRNA-31 in living cancer cells.

Org Biomol Chem 2016 Jun 26;14(22):5001-6. Epub 2016 Apr 26.

Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany.

Two molecular beacons were designed as complementary fluorescent imaging probes for miRNA-21 and miRNA-31. Both beacons were prepared by a combination of solid-phase protocol and Cu(i)-catalyzed cycloaddition chemistry. The four photostable and bright fluorophores were attached to 2'-positions in the stem part of the two beacons. One beacon was labeled by a green-to-red emitting and the other by a blue-to-yellow emitting energy transfer pair. This two by two combination yields the four color emission readout. In vitro experiments demonstrate rapid and highly selective opening of both molecular beacons upon addition of the complementary target RNA and excellent green : red and blue : yellow emission color contrasts. Confocal microscopy of selected cancer cell lines provides evidence that a four color imaging of versicular miRNA-21 and miRNA-31 can be achieved both selectively and simultaneously upon transfection by the beacons, and that the fluorescent readouts track well with miRNA levels determined by PCR.
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http://dx.doi.org/10.1039/c6ob00691dDOI Listing
June 2016

miRs-134 and -370 function as tumor suppressors in colorectal cancer by independently suppressing EGFR and PI3K signalling.

Sci Rep 2016 Apr 20;6:24720. Epub 2016 Apr 20.

Department of Experimental Surgery, Medical Faculty Mannheim, University of Heidelberg, Germany.

Growth factor receptor signalling plays a central and critical role in colorectal cancer. Most importantly, the EGFR signalling cascade involving PI3K/AKT/mTOR and Raf/MEK/ERK pathways are particularly relevant, since they are commonly activated in several cancer entities, including colorectal cancer. In this study, we show that miRs-134 and -370 are both capable of regulating these pathways by targeting EGFR and PIK3CA. In three different colorectal cancer cell lines (DLD1, HCT-116 and RKO), suppression of EGFR and PIK3CA through the enhanced expression of miR-134 or -370 led to a suppression of the key molecules of the PI3K/AKT/mTOR pathway. Furthermore, overexpression of miR-134 or -370 resulted in a significant reduction of cell proliferation, colony formation, migration, invasion and in-vivo tumor growth and metastasis. Concurrent experiments with small interfering RNAs targeting the prime targets show that our selected miRNAs exert a greater functional influence and affect more downstream molecules than is seen with silencing of the individual proteins. Taken together, these data indicate that miRs-134 and -370 are potential tumour suppressor miRNAs and could play a fundamental role in suppressing colorectal cancer tumorigenesis through their ability to co-ordinately regulate EGFR signalling cascade by independently targeting EGFR and PIK3CA.
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http://dx.doi.org/10.1038/srep24720DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4837379PMC
April 2016

MicroRNAs as novel targets and tools in cancer therapy.

Cancer Lett 2017 02 1;387:84-94. Epub 2016 Apr 1.

Department of Experimental Surgery, Medical Faculty Mannheim, and Center for Biomedicine and Medical Technology Mannheim (CBTM), Ruprecht-Karls University of Heidelberg, Ludolf-Krehl-Str. 6, 68135 Mannheim, Germany. Electronic address:

MicroRNAs (miRNAs) are currently experiencing a renewed peak of attention not only as diagnostics but also especially as highly promising novel targets or tools for clinical therapy in several different malignant diseases. Moreover, the recent discovery of competing endogenous RNAs (ceRNAs) as novel miRNA-regulators has contributed exciting insights in this regard. Therefore, this review summarizes and discusses the latest findings on (1) how miRNAs have become therapeutic targets of diverse synthetic antagonists, (2) how novel endogenous regulators of miRNAs such as ceRNAs or pseudogenes could emerge as therapeutics scavenging oncogenic miRNAs and (3) how miRNAs themselves are already, and will increasingly be, used as therapeutics. Recent advances on the importance of miRNA-target affinity and the subcellular localization of miRNAs are also discussed. The potential of these developments in different tumor entities and particular hallmarks of cancer such as metastasis, disease progression, interactions with the tumor microenvironment, or cancer stem cells are equally highlighted.
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http://dx.doi.org/10.1016/j.canlet.2016.03.043DOI Listing
February 2017

MicroRNA Regulation of Epithelial to Mesenchymal Transition.

J Clin Med 2016 Jan 14;5(1). Epub 2016 Jan 14.

Department of Experimental Surgery, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Ruprecht Karl University of Heidelberg, Ludolf-Krehl-Str. 6, 68135 Mannheim, Germany.

Epithelial to mesenchymal transition (EMT) is a central regulatory program that is similar in many aspects to several steps of embryonic morphogenesis. In addition to its physiological role in tissue repair and wound healing, EMT contributes to chemo resistance, metastatic dissemination and fibrosis, amongst others. Classically, the morphological change from epithelial to mesenchymal phenotype is characterized by the appearance or loss of a group of proteins which have come to be recognized as markers of the EMT process. As with all proteins, these molecules are controlled at the transcriptional and translational level by transcription factors and microRNAs, respectively. A group of developmental transcription factors form the backbone of the EMT cascade and a large body of evidence shows that microRNAs are heavily involved in the successful coordination of mesenchymal transformation and vice versa, either by suppressing the expression of different groups of transcription factors, or otherwise acting as their functional mediators in orchestrating EMT. This article dissects the contribution of microRNAs to EMT and analyzes the molecular basis for their roles in this cellular process. Here, we emphasize their interaction with core transcription factors like the zinc finger enhancer (E)-box binding homeobox (ZEB), Snail and Twist families as well as some pluripotency transcription factors.
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http://dx.doi.org/10.3390/jcm5010008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4730133PMC
January 2016