MOLECULAR AND CLINICAL ONCOLOGY 14: 15, 2021 Relationship between MUTYH, OGG1 and BRCA1 mutations and mRNA expression in breast and ovarian cancer predisposition CARMELO MOSCATELLO1, MARTA DI NICOLA1, SERENA VESCHI2, PATRIZIA DI GREGORIO3, ETTORE CIANCHETTI1, LIBORIO STUPPIA4, PASQUALE BATTISTA1, ALESSANDRO CAMA2, MARIA CRISTINA CURIA1 and GITANA MARIA ACETO1 Departments of 1Medical, Oral and Biotechnological Sciences and 2Pharmacy, ‘G. d'Annunzio’ University of Chieti‑Pescara; 3Department of Psychological, Health and Territorial Sciences, School of Medicine and Health Sciences, ‘G. d'Annunzio’ University of Chieti‑Pescara; 4Immunohaematology and Transfusional Medicine Service, ‘SS. Annunziata’ Hospital, I‑66100 Chieti, Italy Received February 14, 2020; Accepted September 29, 2020 DOI: 10.3892/mco.2020.2177 Abstract. The aetiology of breast and ovarian cancer (BC/OC) family history of cancer, and MUTYH p.Val234Gly in a patient is multi‑factorial. At present, the involvement of base excision with OC, also with a family history of cancer. A significant repair (BER) glycosylases (MUTYH and OGG1) in BC/OC reduced transcript expression in MUTYH was observed predisposition is controversial. The present study investigated (P=0.033) in cases, and in association with the presence of whether germline mutation status and mRNA expression rare variants in the same gene (P=0.030). A significant corre‑ of two BER genes, MUTHY and OGG1, were correlated lation in the expression of the two BER genes was observed with BRCA1 in 59 patients with BC/OC and 50 matched in cases (P=0.004), whereas OGG1 and BRCA1 was signifi‑ population controls. In addition, to evaluate the relationship cantly correlated in cases (P=0.001) compared with controls between MUTYH, OGG1 and BRCA1, their possible mutual (P=0.010). The results of the present study indicated that the modulation and correlation among mutational spectrum, gene relationship among mutational spectrum, gene expression and expression and demographic characteristics were evaluated. demographic characteristics may improve the genetic diag‑ The results identified 18 MUTYH and OGG1 variants, of nosis and primary prevention of at‑risk individuals belonging which 4 were novel (2 MUTYH and 2 OGG1) in 44 of the to families with reduced mRNA expression, regardless of 59 patients. In addition, two pathogenic mutations were iden‑ mutation presence. tified:OGG1 p.Arg46Gln, detected in a patient with BC and a Introduction Breast cancer (BC) is the second most common cancer worldwide (1), and the first cause of cancer death among Correspondence to: Professor Gitana Maria Aceto, Department women in across all age groups (1). The etiology of BC is of Medical, Oral and Biotechnological Sciences, ‘G. d'Annunzio’ multifactorial, and both endogenous and environmental factors University of Chieti‑Pescara, Via dei Vestini 31, I‑66100 Chieti, Italy E‑mail: [email protected] are implicated in its pathogenesis (2). The risk of BC and/or ovarian cancer (OC) is increased Abbreviations: APC, adenomatous polyposis coli; BC, breast in carriers of deleterious mutations in BRCA1 and BRCA2, cancer; BC/OC, breast and/or ovarian cancer; BER, base excition these two high penetrance genes encode for proteins involved repair; BOC, breast and ovarian cancer; CRC, colorectal carcinoma; in DNA damage response and repair (3). Among endogenous DHPLC, denaturing high performance liquid chromatography; factors, oxidative stress (OS) produces potentially mutagenic HGVS, Human Genome Variations Society; IQR, interquartile range; reactive oxygen species (ROS) and can play an important LOH, loss of heterozygosity; MAF, minor allele frequency; MAP, role in breast carcinogenesis (4); since breast tissue can be MUTYH‑associated polyposis; MUTYH, mutY DNA glycosylase; particularly exposed to OS due to estrogen metabolism and OC, ovarian cancer; OGG1, 8‑oxoguanine DNA glycosylase; hormonal status (5‑9). Considering that DNA damage may PARP, poly‑(ADP‑ribose) polymerase; PBMD, peripheral blood contribute to breast cancer development, an efficient repair of mononuclear cells; RT‑qPCR, reverse transcription‑quantitative PCR; ROS, reactive oxygen species; VUS, variant of unknown oxidative lesions is expected to protect mammary cells from clinical significance neoplastic transformation. Among the genes involved in the response and repair of DNA damage, BRCA1 has been shown Key words: breast cancer, ovarian cancer, prevention, mutation, to have a decisive role, since it induces the gene expression gene expression, BRCA1, MUTYH, OGG1, base excision repair, of the antioxidant response and thus protecting cells from oxidative stress OS (10). In particular, BRCA1 stimulates the activity of key base excision repair (BER) enzymes, including 8‑oxogua‑ nine DNA glycosylase (OGG1), primarily by increasing 2 MOSCATELLO et al: MUTYH, OGG1 AND BRCA1 RELATIONSHIP IN BC/OC PREDISPOSITION transcription of BER enzymes (10). The BER pathway is Materials and methods responsible for the repair of many DNA nucleobases modi‑ fied, indeed its action is essential for the maintenance of Patients and nucleic acid preparation. The study was genetic integrity and stability (11) and in playing a crucial conducted on a series of BC/OC unrelated Italian patients role in repair of DNA damage induced by ROS (12). BER previously analyzed for BRCA1/2 as a public health service glycosylases may provide a genome surveillance mechanism between 2000 and 2006 from Medical Genetic Service of and may act as molecular sensors that induce apoptosis in University ‘G. d'Annunzio’ of Chieti (27,28). The study was response to extensive DNA damage through interaction of performed after completion of the standardized routine complex pathways (13‑15). A deficiency and/or inactivity of diagnostic investigations. Familiar pedigrees of the cases the BER DNA glycosylase enzymes can induce deleterious were not updated during the course of the study and only outcomes in the cells driving the onset of various tumors (11). the original pedigrees were considered. DNA samples were In particular, OGG1 (MIM 601982) and MUTYH (MIM obtained from 59 patients and RNA from 51. We also anal‑ 604933) remove DNA oxidative purine lesions and seem ysed 120 consecutive population healthy blood donors. This involved in the regulation of cell‑cycle progression and cell population was used to assess the frequency of rare vari‑ division under OS (16,17). In fact, low activity and/or reduced ants in gDNA analyses. RNA from 50 age and sex matched expression of MUTYH and OGG1 enzymes may result in control individuals was employed to analyze gene expression DNA repair impairment and failure to induce apoptosis in and 16 of these women reported positive family history for response to oxidative damage, resulting in survival of cells cancer. All patients and control individuals provided written with oncogenic mutations (12,18,19). In previous studies the informed consent and the study was approved by the Ethics contribution to BC risk due to MUTYH seems to be limited Committee of the University ‘G. d'Annunzio’ of Chieti. or not relevant, although in most researches only specific Nucleic acid extraction from peripheral blood mononuclear mutations of MUTYH were considered, which had previ‑ cells (PBMCs) and synthesis of complementary DNA (cDNA) ously been characterized in families with gastrointestinal from 1.5 µg of total RNA were performed as previously polyposis (20‑22). Also the OGG1 contribution to BC risk described (29). has been significantly associated with the presence of some polymorphic nucleotide markers (SNPs) (21,23‑25). However, Sequence variants analysis. The coding sequence and these associations may have been influenced by the charac‑ intron‑exon borders of MUTYH (GeneID: 4595; MIM 604933; teristics of the population examined or by the specificity Gene Bank accession number: NM _12222.1) and OGG1 of each germinal variant considered (21‑24). To date, the (GeneID: 4968; MIM 601982; Gene Bank accession number: contribution to BC or OC predisposition due to the reduced NM_016821) were analyzed in patients and controls by expression of these genes has not yet been considered in denaturing high performance liquid chromatography (DHPLC) humans. Some doubts remain about the genetic susceptibility after PCR amplification (Wave 1100, Transgenomic Inc.), related to low penetrance genes and their expression, which followed by direct sequencing of samples showing unique could contribute to the onset of BC and/or OC (BC/OC) in profiles. people belonging to families with tumor phenotypes other Primer sequences for MUTYH genes were based on those than BC/OC (e.g. pancreas, thyroid and colon) or in patients reported previously (29), whereas, primers for OGG1 are listed with early onset of cancer and without family history (26). in supplementary Table SI. The patients with these characteristics and without germline To estimate the frequency of novel mutations we mutations in high‑penetrance BRCA1/2 genes might be a examined 240 chromosomes from control individuals, good model to clarify some aspects that contribute to the from the same geographical area, with no personal history multifactorial etiology of BC and OC. of BC/OC and colorectal cancer (CC). All mutations were In light of the above, it can be assumed that genetic confirmed by sequencing of independent PCRs. The nomen‑ variability related to low expression in enzymes that protect clature of sequence variants follows the guidelines proposed cellular DNA from oxidative