Mazen Makarem

Uniformed Services University of the Health Sciences, Bethesda, MD, United States

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Publications (7)35.39 Total impact

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    ABSTRACT: The long arm of chromosome 6 is frequently deleted in diverse human neoplasms. Our previous study showed a minimum deletion region between markers D6S1056 and D6S300 on chromosome 6q in primary prostate cancer (CaP). In this study, we further refined a 200-kb minimal region of deletion (6qTSG1) centered around D6S1013 marker. The 6qTSG1 transcripts contained complex multiple splicing variants with low or absent expression in CaP cells. None of the transcripts identified contained open reading frames that code for a protein in the NCBI database. The expression of 6qTSG transcripts revealed interesting hormonal regulation relevant to CaP biology. Expression of 6q TSG transcript was induced in LNCaP cells that were cultured in charcoal-stripped serum medium suggesting an upregulation of 6qTSG transcript by androgen ablation and cell growth inhibition/apoptosis. Induction of 6qTSG1 expression in response to androgen ablation was abrogated in androgen-independent derivatives of LNCaP cells. In summary, we have defined a candidate CaP suppressor locus on chromosome 6q16.1, and deletions of this locus are frequently associated with prostate tumorigenesis. In the light of emerging role of noncoding RNAs in cancer biology including CaP, future investigations of 6qTSG11 locus is warranted.
    DNA and Cell Biology 12/2006; 25(11):597-607. · 2.34 Impact Factor
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    ABSTRACT: PSGR is a novel member of the G-protein-coupled olfactory receptor family. Our initial report showed predominant expression of the PSGR in human prostate gland and significant alterations of PSGR expression in primary prostate cancer (CaP) specimens. The aim of this study was to provide in-depth evaluations of the expression profile of PSGR in prostatic epithelial cells of CaP patients and to evaluate the association of PSGR expression characteristics with clinico-pathologic features. In total, 220 RNA specimens, from laser capture microdissected paired benign and malignant prostatic epithelial cells of 110 CaP patients, were analyzed for PSGR expression by quantitative real-time PCR. The differential expression of PSGR between the prostatic epithelial cells of malignant and benign glands was statistically significant (P<0.0001). Comparison of PSGR expression between paired benign and tumor cells revealed prostate tumor cell-specific overexpression in 67.2% of tumor specimens (74 of 110), decreased expression in 20.9% of tumor specimens (23 of 110) and no difference of PSGR expression between tumor and normal cells in 11.8% of specimens (13 of 110). In representative cases, PSGR expression patterns were independently confirmed by in situ RNA hybridization. The PSGR overexpression associated with higher percentage of pathologic stage, pT3, and a higher level of preoperative serum PSA. CaP cells of African-American CaP patients exhibited about two-fold increase of PSGR expression in comparison to the Caucasian American CaP patients. Strikingly high-percentage CaP cells overexpress PSGR warrants further studies of PSGR expression alterations to define subsets of CaPs.
    Prostate Cancer and Prostatic Diseases 01/2006; 9(1):56-61. · 2.81 Impact Factor
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    ABSTRACT: PCGEM1 is a novel, highly prostate tissue-specific, androgen-regulated gene. Here, we demonstrate that PCGEM1 expression is significantly higher in prostate cancer (CaP) cells of African-American men than in Caucasian-American men (P=0.0002). Further, increased PCGEM1 expression associates with normal prostate epithelial cells of CaP patients with a family history of CaP (P=0.0400). PCGEM1 overexpression in LNCaP and in NIH3T3 cells promotes cell proliferation and a dramatic increase in colony formation, suggesting a biological role of PCGEM1 in cell growth regulation. Taken together, the cell proliferation/colony formation-promoting functions of PCGEM1 and the association of its increased expression with high-risk CaP patients suggest the potential roles of PCGEM1 in CaP onset/progression, especially in these high-risk groups.
    Oncogene 02/2004; 23(2):605-11. · 8.56 Impact Factor
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    ABSTRACT: PMEPA1 was originally identified as a highly androgen-induced gene by serial analysis of gene expression in androgen-treated LNCaP prostate cancer (CaP) cells. PMEPA1 expression is prostate abundant and restricted to prostatic epithelial cells. PMEPA1-encoded protein shows high sequence homology to a mouse N4wbp4-encoded protein that binds to Nedd4 protein, an E3 ubiquitin-protein ligase involved in ubiquitin-dependent, proteasome-mediated protein degradation. Studies from our and other laboratories have suggested the role of PMEPA1 in cell growth regulation as noted by androgen induction of PMEPA1 expression, elevated PMEPA1 expression in nontumorigenic revertants of tumor cell lines after chromosome 8p transfer, and PMEPA1 expression alterations (up- or down-regulation) in human tumors. Here, we demonstrate that PMEPA1 protein through its PY motifs interacts with WW domains of the human NEDD4 protein. Exogenous expression of PMEPA1, in widely used CaP cell lines DU145, PC3, LNCaP, and LNCaP sublines (C4, C4-2, and C4-2B), conferred cell growth inhibition, and at least one of the PY motifs of PMEPA1 may be involved in its cell growth inhibitory functions. Quantitative expression analysis of PMEPA1 in paired normal and tumor cells of 62 patients with primary CaP revealed tumor cells associated decreased expression in 40 of 62 patients that were significantly associated with higher pathologic stage and serum prostate-specific antigen. Taken together, PMEPA1 negatively regulates growth of androgen responsive or refractory CaP cells, and these functions may be mediated through the interaction of PMEPA1 with the NEDD4 protein involved in the ubiquitin-proteasome pathway. Loss or reduced PMEPA1 expression in CaP further suggests for its role in prostate tumorigenesis.
    Cancer Research 09/2003; 63(15):4299-304. · 8.65 Impact Factor
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    ABSTRACT: Evaluations of androgen regulated gene (ARG) repertoire provide new insights into the androgen receptor (AR) mediated signaling at the transcriptional level. Definition of ARGs having critical functions in the biology of normal and malignant prostate should aid in identifying new bio-markers and therapeutic targets for prostate cancer (CaP). Using Affymetrix HuGene FL oligonucleotide arrays, temporal expression profiles of ARGs in widely used hormone responsive LNCaP cells, were analysed by hierarchical clustering methods and functional classification. ARGs in response to different androgen concentrations showed temporal co-regulation of genes involved in specific biochemical pathways. This study focuses on our new observations of the coordinated androgen induction of genes (NDRG1, PDIR, HERPUD1, ORP150) involved in the endoplasmic reticulum (ER) stress response pathway. Expression analysis of the two selected ER stress responsive genes, NDRG1 and HERPUD1 in primary CaPs revealed a significantly reduced tumor associated expression. Intriguing linkage of the androgen signaling to ER stress responsive genes, a protective response to protein unfolding or protein damage resulting from cellular stress signals, suggests that androgens may induce such stress signals in CaP cells. Decreased CaP associated expression of two ER stress responsive genes also suggests that possible abrogation of this pathway in prostate tumorigenesis.
    Oncogene 01/2003; 21(57):8749-58. · 8.56 Impact Factor
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    ABSTRACT: Deletion of chromosome 16q is frequently associated with diverse tumors. Numerous studies strongly suggest the presence of one or more tumor suppressor genes on chromosome 16q22 to 16qter including the widely studied cadherin gene family. However, the specific tumor suppressor genes residing in this region need better definition and characterization. Standard molecular biology approaches have been used to clone and characterize the DERPC cDNA and its protein product on chromosome 16q22.1. Northern blotting was used to define the expression pattern in a multiple human tissue blots. DERPC expression was examined in multi-tumor array (Clontech, CA, USA) dot blot as well as in laser capture microdissection (LCM) derived prostate cancer (CaP) specimens by quantitative RT-PCR. Western blot analysis and a fluorescent microscopy were used to characterize the molecular size and the cellular location of green fluorescent protein (GFP)-tagged DERPC fusion proteins. A colony formation assay was conducted to determine the effects of DERPC expression on tumor cell growth. A novel gene DERPC (Decreased Expression in Renal and Prostate Cancer) was identified and characterized. DERPC encoded a strong basic, proline- and glycine-rich nuclear protein. DERPC was ubiquitously expressed, with abundant expression in kidney, skeletal muscle, testis, liver, ovary, and heart and moderate expression in prostate. DERPC expression was reduced in renal (67%) and prostate tumors (33%). Expression of DERPC has inhibitory potential on CaP cell growth. Further, overexpression of DERPC in LNCaP cells caused alterations of nuclear morphology. This study suggests that decreased expression of DERPC may be implicated in tumorigenesis of renal and CaPs.
    Molecular Medicine 11/2002; 8(10):655-63. · 4.47 Impact Factor
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    ABSTRACT: Background: Deletion of chromosome 16q is frequently associated with diverse tumors. Numerous studies strongly suggest the presence of one or more tumor sup-pressor genes on chromosome 16q22 to 16qter including the widely studied cadherin gene family. However, the specific tumor suppressor genes residing in this region need better definition and characterization. Material and Methods: Standard molecular biology ap-proaches have been used to clone and characterize the DERPC cDNA and its protein product on chromosome 16q22.1. Northern blotting was used to define the ex-pression pattern in a multiple human tissue blots. DERPC expression was examined in multi-tumor array (Clontech, CA, USA) dot blot as well as in laser capture microdissection (LCM) derived prostate cancer (CaP) specimens by quantitative RT-PCR. Western blot analy-sis and a fluorescent microscopy were used to character-ize the molecular size and the cellular location of green Address correspondence and reprints requests to: e-mail: zzou@cpdr.org. The opinions and assertions contained herein are the private views of the authors and are not to be considered as reflecting the views of the U.S. Army or the Department of Defense. fluorescent protein (GFP)-tagged DERPC fusion pro-teins. A colony formation assay was conducted to deter-mine the effects of DERPC expression on tumor cell growth. Results: A novel gene DERPC (Decreased Expression in Renal and Prostate Cancer) was identified and character-ized. DERPC encoded a strong basic, proline-and glycine-rich nuclear protein. DERPC was ubiquitously expressed, with abundant expression in kidney, skeletal muscle, testis, liver, ovary, and heart and moderate expression in prostate. DERPC expression was reduced in renal (67%) and prostate tumors (33%). Expression of DERPC has in-hibitory potential on CaP cell growth. Further, overex-pression of DERPC in LNCaP cells caused alterations of nuclear morphology. Conclusion: This study suggests that decreased expres-sion of DERPC may be implicated in tumorigenesis of renal and CaPs.
    Molecular Medicine North Shore-LIJ Research Institute. 01/2002; 8:655-663.