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Kulsh J. Biochemistry-Not Oncogenes-May Demystify and Defeat Cancer. Oncol Ther 2023:10.1007/s40487-023-00221-y. [PMID: 36781712 DOI: 10.1007/s40487-023-00221-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 01/24/2023] [Indexed: 02/15/2023] Open
Abstract
The presence of mutated genes strongly correlates with the incidence of cancer. Decades of research, however, has not yielded any specific causative gene or set of genes for the vast majority of cancers. The Cancer Genome Atlas program was supposed to provide clarity, but it only gave much more data without any accompanying insight into how the disease begins and progresses. It may be time to notice that epidemiological studies consistently show that the environment, not genes, has the principal role in causing cancer. Since carcinogenic chemicals in our food, drink, air, and water are the primary culprits, we need to look at the biochemistry of cancer, with a focus on enzymes that invariably facilitate transformations in a cell. In particular, attention should be paid to the rate-limiting enzyme in DNA synthesis, ribonucleotide reductase (RnR), whose activity is tightly linked to tumor growth. Besides circumstantial evidence that cancer is induced at this enzyme's vulnerable free-radical-containing active site by various carcinogens, its role in initiating retinoblastoma and human papillomavirus (HPV)-related cervical cancers has been well documented in recent years. Blocking the activity of malignant RnR is a certain way to arrest cancer.
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Affiliation(s)
- Jay Kulsh
- Independent Scientist, Los Angeles, CA, USA.
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Almstrup K, Frederiksen H, Andersson AM, Juul A. Levels of endocrine-disrupting chemicals are associated with changes in the peri-pubertal epigenome. Endocr Connect 2020; 9:845-857. [PMID: 32755991 PMCID: PMC7487188 DOI: 10.1530/ec-20-0286] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/04/2020] [Indexed: 12/23/2022]
Abstract
Puberty marks a transition period, which leads to the attainment of adult sexual maturity. Timing of puberty is a strongly heritable trait. However, large genetic association studies can only explain a fraction of the observed variability and striking secular trends suggest that lifestyle and/or environmental factors are important. Using liquid-chromatography tandem-mass-spectrometry, we measured endocrine-disrupting chemicals (EDCs; triclosan, bisphenol A, benzophenone-3, 2,4-dichlorophenol, 11 metabolites from 5 phthalates) in longitudinal urine samples obtained biannually from peri-pubertal children included in the COPENHAGEN puberty cohort. EDC levels were associated with blood DNA methylation profiles from 31 boys and 20 girls measured both pre- and post-pubertally. We found little evidence of single methylation sites that on their own showed association with urinary excretion levels of EDCs obtained either the same-day or measured as the yearly mean of dichotomized EDC levels. In contrast, methylation of several promoter regions was found to be associated with two or more EDCs, overlap with known gene-chemical interactions, and form a core network with genes known to be important for puberty. Furthermore, children with the highest yearly mean of dichotomized urinary phthalate metabolite levels were associated with higher promoter methylation of the thyroid hormone receptor interactor 6 gene (TRIP6), which again was mirrored by lower circulating TRIP6 protein levels. In general, the mean TRIP6 promoter methylation was mirrored by circulating TRIP6 protein levels. Our results provide a potential molecular mode of action of how exposure to environmental chemicals may modify pubertal development.
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Affiliation(s)
- Kristian Almstrup
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Correspondence should be addressed to K Almstrup:
| | - Hanne Frederiksen
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Anna-Maria Andersson
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Anders Juul
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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Pubertal development in healthy children is mirrored by DNA methylation patterns in peripheral blood. Sci Rep 2016; 6:28657. [PMID: 27349168 PMCID: PMC4923870 DOI: 10.1038/srep28657] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 06/07/2016] [Indexed: 12/21/2022] Open
Abstract
Puberty marks numerous physiological processes which are initiated by central activation of the hypothalamic–pituitary–gonadal axis, followed by development of secondary sexual characteristics. To a large extent, pubertal timing is heritable, but current knowledge of genetic polymorphisms only explains few months in the large inter-individual variation in the timing of puberty. We have analysed longitudinal genome-wide changes in DNA methylation in peripheral blood samples (n = 102) obtained from 51 healthy children before and after pubertal onset. We show that changes in single methylation sites are tightly associated with physiological pubertal transition and altered reproductive hormone levels. These methylation sites cluster in and around genes enriched for biological functions related to pubertal development. Importantly, we identified that methylation of the genomic region containing the promoter of TRIP6 was co-ordinately regulated as a function of pubertal development. In accordance, immunohistochemistry identified TRIP6 in adult, but not pre-pubertal, testicular Leydig cells and circulating TRIP6 levels doubled during puberty. Using elastic net prediction models, methylation patterns predicted pubertal development more accurately than chronological age. We demonstrate for the first time that pubertal attainment of secondary sexual characteristics is mirrored by changes in DNA methylation patterns in peripheral blood. Thus, modulations of the epigenome seem involved in regulation of the individual pubertal timing.
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Wasik KA, Tam OH, Knott SR, Falciatori I, Hammell M, Vagin VV, Hannon GJ. RNF17 blocks promiscuous activity of PIWI proteins in mouse testes. Genes Dev 2015; 29:1403-15. [PMID: 26115953 PMCID: PMC4511215 DOI: 10.1101/gad.265215.115] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 06/03/2015] [Indexed: 01/21/2023]
Abstract
PIWI proteins and their associated piRNAs protect germ cells from the activity of mobile genetic elements. Two classes of piRNAs—primary and secondary—are defined by their mechanisms of biogenesis. Primary piRNAs are processed directly from transcripts of piRNA cluster loci, whereas secondary piRNAs are generated in an adaptive amplification loop, termed the ping-pong cycle. In mammals, piRNA populations are dynamic, shifting as male germ cells develop. Embryonic piRNAs consist of both primary and secondary species and are mainly directed toward transposons. In meiotic cells, the piRNA population is transposon-poor and largely restricted to primary piRNAs derived from pachytene piRNA clusters. The transition from the embryonic to the adult piRNA pathway is not well understood. Here we show that RNF17 shapes adult meiotic piRNA content by suppressing the production of secondary piRNAs. In the absence of RNF17, ping-pong occurs inappropriately in meiotic cells. Ping-pong initiates piRNA responses against not only transposons but also protein-coding genes and long noncoding RNAs, including genes essential for germ cell development. Thus, the sterility of Rnf17 mutants may be a manifestation of a small RNA-based autoimmune reaction.
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Affiliation(s)
- Kaja A Wasik
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, New York 11724, USA; Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, New York 11724, USA
| | - Oliver H Tam
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, New York 11724, USA
| | - Simon R Knott
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, New York 11724, USA; Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, New York 11724, USA
| | - Ilaria Falciatori
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, New York 11724, USA; Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, New York 11724, USA
| | - Molly Hammell
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, New York 11724, USA
| | - Vasily V Vagin
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, New York 11724, USA; Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, New York 11724, USA
| | - Gregory J Hannon
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, New York 11724, USA; Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, New York 11724, USA; Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge CB2 0RE, United Kingdom
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Tsutsumi M, Fujiwara R, Nishizawa H, Ito M, Kogo H, Inagaki H, Ohye T, Kato T, Fujii T, Kurahashi H. Age-related decrease of meiotic cohesins in human oocytes. PLoS One 2014; 9:e96710. [PMID: 24806359 PMCID: PMC4013030 DOI: 10.1371/journal.pone.0096710] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 04/10/2014] [Indexed: 12/22/2022] Open
Abstract
Aneuploidy in fetal chromosomes is one of the causes of pregnancy loss and of congenital birth defects. It is known that the frequency of oocyte aneuploidy increases with the human maternal age. Recent data have highlighted the contribution of cohesin complexes in the correct segregation of meiotic chromosomes. In mammalian oocytes, cohesion is established during the fetal stages and meiosis-specific cohesin subunits are not replenished after birth, raising the possibility that the long meiotic arrest of oocytes facilitates a deterioration of cohesion that leads to age-related increases in aneuploidy. We here examined the cohesin levels in dictyate oocytes from different age groups of humans and mice by immunofluorescence analyses of ovarian sections. The meiosis-specific cohesin subunits, REC8 and SMC1B, were found to be decreased in women aged 40 and over compared with those aged around 20 years (P<0.01). Age-related decreases in meiotic cohesins were also evident in mice. Interestingly, SMC1A, the mitotic counterpart of SMC1B, was substantially detectable in human oocytes, but little expressed in mice. Further, the amount of mitotic cohesins of mice slightly increased with age. These results suggest that, mitotic and meiotic cohesins may operate in a coordinated way to maintain cohesions over a sustained period in humans and that age-related decreases in meiotic cohesin subunits impair sister chromatid cohesion leading to increased segregation errors.
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Affiliation(s)
- Makiko Tsutsumi
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, Japan
| | - Reiko Fujiwara
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, Japan
| | - Haruki Nishizawa
- Department of Obstetrics and Gynecology, Fujita Health University, Toyoake, Aichi, Japan
| | - Mayuko Ito
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, Japan
- Department of Obstetrics and Gynecology, Fujita Health University, Toyoake, Aichi, Japan
| | - Hiroshi Kogo
- Department of Anatomy and Cell Biology, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Hidehito Inagaki
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, Japan
| | - Tamae Ohye
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, Japan
| | - Takema Kato
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, Japan
| | - Takuma Fujii
- Department of Obstetrics and Gynecology, Fujita Health University, Toyoake, Aichi, Japan
| | - Hiroki Kurahashi
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, Japan
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