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Rotimi SO, Rotimi OA, Salhia B. A Review of Cancer Genetics and Genomics Studies in Africa. Front Oncol 2021; 10:606400. [PMID: 33659210 PMCID: PMC7917259 DOI: 10.3389/fonc.2020.606400] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 12/14/2020] [Indexed: 12/24/2022] Open
Abstract
Cancer is the second leading cause of death globally and is projected to overtake infectious disease as the leading cause of mortality in Africa within the next two decades. Cancer is a group of genomic diseases that presents with intra- and inter-population unique phenotypes, with Black populations having the burden of morbidity and mortality for most types. At large, the prevention and treatment of cancers have been propelled by the understanding of the genetic make-up of the disease of mostly non-African populations. By the same token, there is a wide knowledge gap in understanding the underlying genetic causes of, and genomic alterations associated with, cancer among black Africans. Accordingly, we performed a review of the literature to survey existing studies on cancer genetics/genomics and curated findings pertaining to publications across multiple cancer types conducted on African populations. We used PubMed MeSH terms to retrieve the relevant publications from 1990 to December 2019. The metadata of these publications were extracted using R text mining packages: RISmed and Pubmed.mineR. The data showed that only 0.329% of cancer publications globally were on Africa, and only 0.016% were on cancer genetics/genomics from Africa. Although the most prevalent cancers in Africa are cancers of the breast, cervix, uterus, and prostate, publications representing breast, colorectal, liver, and blood cancers were the most frequent in our review. The most frequently reported cancer genes were BRCA1, BRCA2, and TP53. Next, the genes reported in the reviewed publications’ abstracts were extracted and annotated into three gene ontology classes. Genes in the cellular component class were mostly associated with cell part and organelle part, while those in biological process and molecular function classes were mainly associated with cell process, biological regulation, and binding, and catalytic activity, respectively. Overall, this review highlights the paucity of research on cancer genomics on African populations, identified gaps, and discussed the need for concerted efforts to encourage more research on cancer genomics in Africa.
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Affiliation(s)
- Solomon O Rotimi
- Department of Translational Genomics, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.,Department of Biochemistry, Covenant University, Ota, Nigeria
| | - Oluwakemi A Rotimi
- Department of Translational Genomics, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.,Department of Biochemistry, Covenant University, Ota, Nigeria
| | - Bodour Salhia
- Department of Translational Genomics, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.,Norris Comprehensive Cancer Centre, University of Southern California, Los Angeles, CA, United States
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2
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Luo Y, Liu JY. Pleiotropic Functions of Cytochrome P450 Monooxygenase-Derived Eicosanoids in Cancer. Front Pharmacol 2020; 11:580897. [PMID: 33192522 PMCID: PMC7658919 DOI: 10.3389/fphar.2020.580897] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/30/2020] [Indexed: 12/19/2022] Open
Abstract
Eicosanoids are a class of functionally bioactive lipid mediators derived from the metabolism of long-chain polyunsaturated fatty acids (PUFAs) mediated by multiple enzymes of three main branches, including cyclooxygenases (COXs), lipoxygenases (LOXs), and cytochrome P450s (CYPs). Recently, the role of eicosanoids derived by COXs and LOXs pathways in the control of physiological and pathological processes associated with cancer has been well documented. However, the role of CYPs-mediated eicosanoids, such as epoxyeicosatrienoic acids (EETs), epoxyoctadecenoic acids (EpOMEs), epoxyeicosatetraenoic acids (EpETEs), and epoxydocosapentaenoic acids (EDPs), as well as hydroxyeicosatetraenoic acids (HETEs), in tumorigenesis and cancer progression have not been fully elucidated yet. Here we summarized the association of polymorphisms of CYP monooxygenases with cancers and the pleiotropic functions of CYP monooxygenase-mediated eicosanoids (EETs, EpOMEs, EpETE, EDPs, and 20-HETE) in the tumorigenesis and metastasis of multiple cancers, including but not limited to colon, liver, kidney, breast and prostate cancers, which hopefully provides valuable insights into cancer therapeutics. We believe that manipulation of CYPs with or without supplement of ω-3 PUFAs to regulate eicosanoid profile is a promising strategy to prevent and/or treat cancers.
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Affiliation(s)
- Ying Luo
- Department of Clinical Laboratory, Changning Maternity and Infant Health Hospital, East China Normal University, Shanghai, China
| | - Jun-Yan Liu
- Center for Novel Target & Therapeutic Intervention, Institute of Life Sciences, Chongqing Medical University, Chongqing, China
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Khalaj Z, Baratieh Z, Nikpour P, Khanahmad H, Mokarian F, Salehi R, Salehi M. Distribution of CYP2D6 polymorphism in the Middle Eastern region. JOURNAL OF RESEARCH IN MEDICAL SCIENCES 2019; 24:61. [PMID: 31523247 PMCID: PMC6670283 DOI: 10.4103/jrms.jrms_1076_18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 03/04/2019] [Accepted: 04/10/2019] [Indexed: 12/12/2022]
Abstract
Cytochrome P450 2D6 (CYP2D6) is an important drug-metabolizing enzyme involved in the pharmacokinetic metabolism of drugs. CYP2D6 gene is highly polymorphic, and the combination of its different alleles yields different phenotypes including extensive metabolizer (EM), intermediate metabolizer (IM), poor metabolizer (PM), and ultrarapid metabolizer (UM). Genotyping of the important alleles for this gene in different ethnicities is of particular importance for assessing the efficacy of various drugs. In this study, we reviewed the CYP2D6 allele and phenotype frequencies predicted from the genotypes of CYP2D6 in the Middle East area. Regardless of different ethnicities, the CYP2D6*41 allele frequency was shown to be higher than that of other reduced functional alleles. In addition, CYP2D6*4 was the most frequent nonfunctional allele in all studied populations in the Middle East. Taken together, our findings illustrated that the frequencies of PM or IM alleles and different genotypes harboring these alleles are relatively high in the Middle Eastern countries. Therefore, the study of CYP2D6 alleles for each patient to detect those that are at risk is of great importance to prevent adverse drug reactions through individualization therapy.
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Affiliation(s)
- Zahra Khalaj
- Department of Genetics and Molecular Biology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Zohreh Baratieh
- Department of Genetics and Molecular Biology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Parvaneh Nikpour
- Department of Genetics and Molecular Biology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.,Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non-Communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hossein Khanahmad
- Department of Genetics and Molecular Biology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Fariborz Mokarian
- Cancer Prevention Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Rasoul Salehi
- Department of Genetics and Molecular Biology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.,Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non-Communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mansoor Salehi
- Department of Genetics and Molecular Biology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.,Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non-Communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran.,Cellular, Molecular and Genetics Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
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Sankhwar M, Sankhwar S. Variations in CYP isoforms and bladder cancer: A superfamily paradigm. Urol Oncol 2014; 32:28.e33-40. [DOI: 10.1016/j.urolonc.2012.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2012] [Revised: 08/12/2012] [Accepted: 08/13/2012] [Indexed: 10/27/2022]
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Alessandrini M, Asfaha S, Dodgen TM, Warnich L, Pepper MS. Cytochrome P450 pharmacogenetics in African populations. Drug Metab Rev 2013; 45:253-75. [PMID: 23590174 DOI: 10.3109/03602532.2013.783062] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The Cytochrome P450 (CYP450) family of enzymes is involved in the oxidative metabolism of many therapeutic drugs, carcinogens and various endogenous substrates. These enzymes are highly polymorphic at an inter-individual and inter-ethnic level. Polymorphisms or genetic variations account for up to 30% of inter-individual differences seen in a variety of drug responses. The frequencies of the different metabolizer categories (slow, intermediate, extensive and ultra-rapid), the distribution of genetic variants, genotype-phenotype correlations and the clinical importance of the CYP450 enzymes have been extensively documented in Caucasian and Oriental populations. Limited data exists for African populations, despite the fact that this knowledge is critically important for these populations who experience a heavy burden of communicable and non-communicable diseases. In addition, the costs incurred through adverse drug reactions and non-responsiveness to therapy could be reduced through the wide-scale application of pharmacogenetics. This review provides an overview and investigation of CYP450 genotypic and phenotypic reports published from 1980 to present in African populations. Our findings confirm the high degree of variability that is expected when comparing individuals of African origin to other ethnic groups and also highlight the distribution of clinically relevant CYP450 alleles amongst the various African populations. The notable discordance in genotypic and phenotypic data amongst African populations exemplifies the need for in-depth and well-orchestrated molecular and pharmacological investigations of these populations in the future, for which whole genome sequencing and association studies will be critical.
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Affiliation(s)
- Marco Alessandrini
- Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
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Azarpira N, Ashraf MJ, Khademi B, Darai M, Hakimzadeh A, Abedi E. Study the polymorphism of CYP3A5 and CYP3A4 loci in Iranian population with laryngeal squamous cell carcinoma. Mol Biol Rep 2011; 38:5443-8. [PMID: 21380731 DOI: 10.1007/s11033-011-0699-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Accepted: 02/26/2011] [Indexed: 11/29/2022]
Abstract
Cancer reflects a complicated network of interactions between genes and environmental factors. Cytochrome P450 (CYP) is a multi-gene superfamily participating in the metabolism of xenobiotics. The aim of our study was to examine whether polymorphisms in the CYP enzyme genes affect the risk of developing larynx squamous cell carcinoma (SCC). Polymorphism of CYP3A5 and CYP3A4 genes were investigated in 50 patients with laryngeal SCC and 100 control subjects by polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP). In patients the CYP3A5 3/3 and 1/3genotypes were detected in 92% and 8% respectively. There was no relation between genotype, allele frequency and grade/stage of tumor. In control group, the frequency of CYP3A5 3/3 and CYP3A5 1/3 genotype were 98% and 2% respectively. There was no significant difference in genotype and allele frequency of this gene between patient and control group. In respect of CYP3A41A/B, people in both patient and control groups had the same genotype of CYP3A41A/1A. In this study, the CYP gene variants were not associated with increased risk of laryngeal SCC. Study on the other genetic factors which are involved in activation/detoxication of procarcinogenes, such as CYP1A1, CYP1B1, CYP2E1 and gluthation S transferase is recommended.
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Affiliation(s)
- Negar Azarpira
- Organ Transplant Research Center, Nemazi Hospital, Shiraz University of Medical Sciences, Shiraz, Iran.
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Au WW, Anwar W, Sram RJ, Chulasiri M, Ribeiro LR. International conferences on environmental mutagens in human populations-opportunities, accomplishments and challenges. Mutat Res 2003; 544:93-8. [PMID: 14644311 PMCID: PMC7129191 DOI: 10.1016/j.mrrev.2003.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2003] [Revised: 05/30/2003] [Accepted: 05/30/2003] [Indexed: 11/01/2022]
Abstract
A major mission for organizing the series of International Conferences on Environmental Mutagens in Human Populations is to bring science and scientists to the sites where the field of environmental health is in developmental stages and environmental health is a serious concern. The mission has been fulfilled in each of the previous conferences that were held in Egypt, Czech Republic, Thailand and Brazil. These conferences have led to significant enhancement of regional scientific expertise from the acquisition of scientific knowledge and from the generation of sustainable collaborative programs.
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Affiliation(s)
- William W Au
- Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, 2.102 Ewing Hall, 700 Harborside Drive, Galveston, TX 77555-1110, USA.
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Abdel-Rahman SZ, Salama SA, Au WW, Hamada FA. Role of polymorphic CYP2E1 and CYP2D6 genes in NNK-induced chromosome aberrations in cultured human lymphocytes. PHARMACOGENETICS 2000; 10:239-49. [PMID: 10803680 DOI: 10.1097/00008571-200004000-00005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Polymorphisms in genes of xenobiotic-metabolizing enzymes are largely responsible for interindividual differences in ability to activate and detoxify genotoxic agents and therefore may influence individual susceptibility to environmental cancer. The tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), requires metabolic activation by cytochrome P450 (CYP) enzymes to generate DNA-reactive intermediates that induce mutations and cancer. In the current study, we investigated the role of the polymorphic CYP2E1 and CYP2D6 genes in the genotoxicity of NNK using the tandem-probe fluorescence in-situ hybridization (FISH) chromosome aberration assay as a marker. Our results, using whole blood cultures from 39 volunteers, indicated that NNK (0.12, 0.24 or 0.72 mM) induced a concentration-dependent increase in the frequency of chromosome aberration. The potential role of CYP2E1 and CYP2D6 in NNK-induced genetic damage in cultured human lymphocytes was characterized using specific CYP inhibitors. Treatment of blood cultures with 25 microM diethyldithiocarbamate (DDC), a specific CYP2E1 inhibitor, or 0.5 microM quinidine, a specific CYP2D6 inhibitor, simultaneously with NNK, significantly decreased NNK-induced chromosome aberration. We also studied the role of CYP2E1 and CYP2D6 allelic variants on NNK-induced chromosome aberration. Our results indicate that NNK induced a significantly higher level of chromosome aberration in cells with the CYP2E1 WT/*5B genotype compared to cells with the CYP2E1 WT/WT. In contrast, no difference in NNK-induced chromosome aberration was observed between cells with the CYP2D6 extensive metabolizers compared to cells with the CYP2D6 poor metabolizer genotypes. These results underscore the important role of polymorphic metabolizing genes in influencing the genotoxic responses to environmental mutagens and provide support to the reported findings linking CYP2E1 polymorphism to smoking-related lung cancer.
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Affiliation(s)
- S Z Abdel-Rahman
- Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, Galveston 77555-1110, USA.
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Au WW, Cajas-Salazar N, Salama S. Factors contributing to discrepancies in population monitoring studies. Mutat Res 1998; 400:467-78. [PMID: 9685705 DOI: 10.1016/s0027-5107(98)00058-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A review of the scientific literature on population monitoring studies (on non-accidentally exposed populations) frequently show that many of these studies using similarly exposed populations and the same laboratory techniques do not produce consistent results. To illustrate the problem, a brief review of studies using well validated techniques (chromosome aberrations and hprt gene mutation) to elucidate genotoxic effects of cigarette smoking is presented. Although many factors can contribute to the generation of discrepant results, two obvious factors are small sample sizes and inadequate experimental data. In addition, a new factor on genetic susceptibility should be considered in population studies whenever appropriate. The new factor is based on recent data showing the influence of polymorphic metabolizing genes on response to environmental mutagens towards biological effects and disease outcome. The common ones include the cytochrome P450 and the glutathione S-transferase genes. The inclusion of susceptibility factors in population monitoring may revolutionize the approach for health risk assessment and for environmental regulations.
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Affiliation(s)
- W W Au
- Department of Preventive Medicine and Community Health, Division of Environmental Toxicology, The University of Texas Medical Branch, Galveston, TX 77555-1110, USA.
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