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  1. Article ; Online: Genomic Space of MGMT in Human Glioma Revisited

    Mohammed A. Ibrahim Al-Obaide / Viswanath Arutla / Manny D. Bacolod / Wei Wang / Ruiwen Zhang / Kalkunte S. Srivenugopal

    International Journal of Molecular Sciences, Vol 22, Iss 5, p

    Novel Motifs, Regulatory RNAs, NRF1, 2, and CTCF Involvement in Gene Expression

    2021  Volume 2492

    Abstract: Background: The molecular regulation of increased MGMT expression in human brain tumors, the associated regulatory elements, and linkages of these to its epigenetic silencing are not understood. Because the heightened expression or non-expression of MGMT ...

    Abstract Background: The molecular regulation of increased MGMT expression in human brain tumors, the associated regulatory elements, and linkages of these to its epigenetic silencing are not understood. Because the heightened expression or non-expression of MGMT plays a pivotal role in glioma therapeutics, we applied bioinformatics and experimental tools to identify the regulatory elements in the MGMT and neighboring EBF3 gene loci. Results: Extensive genome database analyses showed that the MGMT genomic space was rich in and harbored many undescribed RNA regulatory sequences and recognition motifs. We extended the MGMT ’s exon-1 promoter to 2019 bp to include five overlapping alternate promoters. Consensus sequences in the revised promoter for (a) the transcriptional factors CTCF, NRF1/NRF2, GAF, (b) the genetic switch MYC/MAX/MAD, and (c) two well-defined p53 response elements in MGMT intron-1, were identified. A putative protein-coding or non-coding RNA sequence was located in the extended 3′ UTR of the MGMT transcript. Eleven non-coding RNA loci coding for miRNAs, antisense RNA, and lncRNAs were identified in the MGMT-EBF3 region and six of these showed validated potential for curtailing the expression of both MGMT and EBF3 genes. ChIP analysis verified the binding site in MGMT promoter for CTCF which regulates the genomic methylation and chromatin looping. CTCF depletion by a pool of specific siRNA and shRNAs led to a significant attenuation of MGMT expression in human GBM cell lines. Computational analysis of the ChIP sequence data in ENCODE showed the presence of NRF1 in the MGMT promoter and this occurred only in MGMT-proficient cell lines. Further, an enforced NRF2 expression markedly augmented the MGMT mRNA and protein levels in glioma cells. Conclusions: We provide the first evidence for several new regulatory components in the MGMT gene locus which predict complex transcriptional and posttranscriptional controls with potential for new therapeutic avenues.
    Keywords MGMT ; DNA repair ; alkylating agents ; brain tumors ; CTCF ; regulatory RNAs ; Biology (General) ; QH301-705.5 ; Chemistry ; QD1-999
    Subject code 570
    Language English
    Publishing date 2021-03-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Characterization of a highly specific NQO1-activated near-infrared fluorescent probe and its application for in vivo tumor imaging

    Surendra Reddy Punganuru / Hanumantha Rao Madala / Viswanath Arutla / Ruiwen Zhang / Kalkunte S. Srivenugopal

    Scientific Reports, Vol 9, Iss 1, Pp 1-

    2019  Volume 12

    Abstract: Abstract The Near-infrared Fluorescence (NIRF) molecular imaging of cancer is known to be superior in sensitivity, deeper penetration, and low phototoxicity compared to other imaging modalities. In view of an increased need for efficient and targeted ... ...

    Abstract Abstract The Near-infrared Fluorescence (NIRF) molecular imaging of cancer is known to be superior in sensitivity, deeper penetration, and low phototoxicity compared to other imaging modalities. In view of an increased need for efficient and targeted imaging agents, we synthesized a NAD(P)H quinone oxidoreductase 1 (NQO1)-activatable NIR fluorescent probe (NIR-ASM) by conjugating dicyanoisophorone (ASM) fluorophore with the NQO1 substrate quinone propionic acid (QPA). The probe remained non-fluorescent until activation by NQO1, whose expression is largely limited to malignant tissues. With a large Stokes shift (186 nm) and a prominent near-infrared emission (646 nm) in response to NQO1, NIR-ASM was capable of monitoring NQO1 activity in vitro and in vivo with high specificity and selectivity. We successfully employed the NIR-ASM to differentiate cancer cells from normal cells based on NQO1 activity using fluorescence microscopy and flow cytometry. Chemical and genetic approaches involving the use of ES936, a specific inhibitor of NQO1 and siRNA and gene transfection procedures unambiguously demonstrated NQO1 to be the sole target activating the NIR-ASM in cell cultures. NIR-ASM was successfully used to detect and image the endogenous NQO1 in three live tumor-bearing mouse models (A549 lung cancer, Lewis lung carcinoma, and MDMAMB 231 xenografts) with a high signal-to-low noise ratiometric NIR fluorescence response. When the NQO1-proficient A549 tumors and NQO1-deficient MDA-MB-231 tumors were developed in the same animal, only the A549 malignancies activated the NIR-ASM probe with a strong signal. Because of its high sensitivity, rapid activation, tumor selectivity, and nontoxic properties, the NIR-ASM appears to be a promising agent with clinical applications.
    Keywords Medicine ; R ; Science ; Q
    Subject code 610 ; 616
    Language English
    Publishing date 2019-06-01T00:00:00Z
    Publisher Nature Publishing Group
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: The design and development of imidazothiazole-chalcone derivatives as potential anticancer drugs.

    Kamal, Ahmed / Kashi Reddy, Methuku / Viswanath, Arutla

    Expert opinion on drug discovery

    2013  Volume 8, Issue 3, Page(s) 289–304

    Abstract: Introduction: Imidazothiazole derivatives have long been therapeutically used for the treatment of various diseases. In recent years, the imidazothiazole and chalcone moieties have emerged as important pharmacophores in the development of antitumor ... ...

    Abstract Introduction: Imidazothiazole derivatives have long been therapeutically used for the treatment of various diseases. In recent years, the imidazothiazole and chalcone moieties have emerged as important pharmacophores in the development of antitumor agents. Imidazothiazole-chalcone conjugates can be accessed by covalently binding these two powerful pharamacophore units. These conjugates are known to exhibit a wide range of biological properties, including anticancer, antimicrobial, anti-inflammatory and immunosuppressive activities. Their promising biological profile and easy synthetic accessibility have triggered investigations directed at the design and development of new imidazothiazole-chalcone conjugate derivatives as potential chemotherapeutics.
    Areas covered: The present review focuses on recent reports of the syntheses and anticancer properties of various imidazothiazoles, chalcones and imidazothiazole-linked chalcone conjugates. Furthermore, the authors discuss the structure-activity relationships (SAR) of imidazothiazoles and chalcones and their conjugates as new antitumor agents, as well as in vitro and in vivo evaluation, clinical use and their future therapeutic applications.
    Expert opinion: A large number of imidazothiazoles, chalcones and a new series of imidazothiazole-chalcone conjugates possess potent anticancer activity that could be further developed as drug candidates. Imidazothiazole-based conjugates could also display synergistic effect, and still there is a need to use the drug combinations permitting lower dose and development of new generation of drugs. Despite encouraging observed results for their response to tumors in clinical studies, full characterization of their toxicity is further required for their clinical usage as safe drugs for the treatment of cancer.
    MeSH term(s) Animals ; Antineoplastic Agents/pharmacology ; Chalcone/analogs & derivatives ; Chalcone/pharmacology ; Drug Design ; Humans ; Imidazoles/pharmacology ; Thiazoles/pharmacology
    Chemical Substances Antineoplastic Agents ; Imidazoles ; Thiazoles ; Chalcone (5S5A2Q39HX)
    Language English
    Publishing date 2013-03
    Publishing country England
    Document type Journal Article ; Review
    ZDB-ID 2259618-5
    ISSN 1746-045X ; 1746-0441
    ISSN (online) 1746-045X
    ISSN 1746-0441
    DOI 10.1517/17460441.2013.758630
    Database MEDical Literature Analysis and Retrieval System OnLINE

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