Browsing by Author "Jara, Lilian"
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- ItemA Single Variant in Pri-miRNA-155 Associated with Susceptibility to Hereditary Breast Cancer Promotes Aggressiveness in Breast Cancer Cells(2022) Landeros, Natalia; Gonzalez-Hormazabal, Patricio; Perez-Moreno, Pablo; Tapia, Julio C.; Jara, LilianVariants in genes encoding for microRNAs have been associated with their deregulation in breast cancer (BC). Sequencing of microRNAs deregulated in BC was performed using DNA from Chilean patients with a strong family history and negative for mutations in BRCA1/BRCA2. Seventeen variants were identified, three of which were selected for a case-control association study: rs376491654 (miR-335), rs755634302 (miR-497), and rs190708267 (miR-155). For rs190708267 C>T, the heterozygous T allele was detected in four BC cases and absent in controls, while homozygous TT cases were not detected. Variants were modelled in silico, cloned in a plasmid, expressed in BC cell lines, and functional in vitro assays were performed. Overexpression of the miR-155-T allele increased mature miR-155-5p levels in both BC cell lines, suggesting that its presence alters pre-miR-155 processing. Moreover, BC cells overexpressing the miR-155-T allele showed increased proliferation, migration, and resistance to cisplatin-induced death compared to miR-155-C overexpressing cells. Of note, the 3 ' UTR of APC, GSK3 beta, and PPP1CA genes, all into the canonical Wnt signaling pathway, were identified as direct targets. APC and GSK3 beta mRNA levels decreased while PP1 levels increased. These results suggest a pathogenic role of the variant rs190708267 (miR-155) in BRCA 1/2 negative BC, conferring susceptibility and promoting traits of aggressiveness.
- ItemAssociation Between Bone Morphogenetic Protein 4 Gene Polymorphisms with Nonsyndromic Cleft Lip with or without Cleft Palate in a Chilean Population(MARY ANN LIEBERT, INC, 2010) Suazo, Jose; Luis Santos, Jose; Jara, Lilian; Blanco, RafaelNonsyndromic cleft lip with or without cleft palate (NSCLP) is one of the most common birth defects in humans with both genetic and environmental components involved in its expression. Experimental evidences have postulated that bone morphogenetic protein 4 gene (Bmp4) is involved in the etiology of cleft lip with or without cleft palate (CL/P) in mice. In our study we analyzed the association between BMP4 and NSCLP in a sample of 150 unrelated trios ascertained through affected probands. Three BMP4 polymorphisms were analyzed, two intronic (rs762642 and rs2855532) and rs1957860, located 5.7 kb upstream from BMP4. Transmission/disequilibrium tests were performed at the allele and haplotype levels. Our results did not detect preferential transmission for individual single-nucleotide polymorphisms. Significant transmission distortion was observed for haplotypes rs1957860-rs762642 (p = 0.18), especially for C-T (p = 0.015) and T-T (p = 0.018) which include the genomic region where the promoter and an enhancer of BMP4 are located. Thus, despite the positive association detected between these haplotypes and NSCLP they probably do not have a functional effect on BMP4 expression or protein activity but possibly reflect NSCLP susceptibility changes which are in linkage disequilibrium with these polymorphisms. The findings of our study support a role for BMP4 in NSCLP in the admixed Chilean population.
- ItemAssociation Between TGFB3 and Nonsyndromic Cleft Lip With or Without Cleft Palate in a Chilean Population(ALLIANCE COMMUNICATIONS GROUP DIVISION ALLEN PRESS, 2010) Suazo, Jose; Luis Santos, Jose; Scapoli, Luca; Jara, Lilian; Blanco, RafaelObjective: To assess the possible association between TGFB3 allele variants and nonsyndromic cleft lip with or without cleft palate in a Chilean population.
- ItemCancer Stem Cell and Aggressiveness Traits Are Promoted by Stable Endothelin-Converting Enzyme-1c in Glioblastoma Cells(2023) Niechi, Ignacio; Erices, Jose I.; Carrillo-Beltran, Diego; Uribe-Ojeda, Atenea; Torres, Angelo; Rocha, Jose Dellis; Uribe, Daniel; Toro, Maria A.; Villalobos-Nova, Karla; Gaete-Ramirez, Belen; Mingo, Gabriel; Owen, Gareth I. I.; Varas-Godoy, Manuel; Jara, Lilian; Aguayo, Francisco; Burzio, Veronica A.; Quezada-Monras, Claudia; Tapia, Julio C. C.Glioblastoma (GBM) is the most common and aggressive type of brain tumor due to its elevated recurrence following treatments. This is mainly mediated by a subpopulation of cells with stemness traits termed glioblastoma stem-like cells (GSCs), which are extremely resistant to anti-neoplastic drugs. Thus, an advancement in the understanding of the molecular processes underlying GSC occurrence should contribute significantly towards progress in reducing aggressiveness. High levels of endothelin-converting enzyme-1 (ECE1), key for endothelin-1 (ET-1) peptide activation, have been linked to the malignant progression of GBM. There are four known isoforms of ECE1 that activate ET-1, which only differ in their cytoplasmic N-terminal sequences. Isoform ECE1c is phosphorylated at Ser-18 and Ser-20 by protein kinase CK2, which increases its stability and hence promotes aggressiveness traits in colon cancer cells. In order to study whether ECE1c exerts a malignant effect in GBM, we designed an ECE1c mutant by switching a putative ubiquitination lysine proximal to the phospho-serines Lys-6-to-Arg (i.e., K6R). This ECE1c(K6R) mutant was stably expressed in U87MG, T98G, and U251 GBM cells, and their behavior was compared to either mock or wild-type ECE1c-expressing clone cells. ECE1c(K6R) behaved as a highly stable protein in all cell lines, and its expression promoted self-renewal and the enrichment of a stem-like population characterized by enhanced neurospheroid formation, as well as increased expression of stem-like surface markers. These ECE1c(K6R)-derived GSC-like cells also displayed enhanced resistance to the GBM-related chemotherapy drugs temozolomide and gemcitabine and increased expression of the ABCG2 efflux pump. In addition, ECE1c(K6R) cells displayed enhanced metastasis-associated traits, such as the modulation of adhesion and the enhancement of cell migration and invasion. In conclusion, the acquisition of a GSC-like phenotype, together with heightened chemoresistance and invasiveness traits, allows us to suggest phospho-ECE1c as a novel marker for poor prognosis as well as a potential therapeutic target for GBM.
- ItemLinkage Disequilibrium Between IRF6 Variants and Nonsyndromic Cleft Lip/Palate in the Chilean Population(2008) Suazo, José; Santos Martín, José Luis; Jara, Lilian; Blanco, Rafael
- ItemParent-of-Origin Effects for MSX1 in a Chilean Population With Nonsyndromic Cleft Lip/Palate(WILEY, 2010) Suazo, Jose; Luis Santos, Jose; Jara, Lilian; Blanco, RafaelBased on association and sequencing studies, investigators have postulated muscle segment homeobox 1 (MSX1) as a strong candidate gene involved in the causation of nonsyndromic cleft lip with or without cleft palate (NSCLP). Parent-of-origin effects have been suggested for some NSCLP candidate genes but not for MSX1. The aims of the present study were to test for allele/haplotype associations applying the transmission disequilibrium test (TDT) and the transmission asymmetry test (TAT) to evaluate the possible parent-of-origin effects of MSX1 in Chilean patients with NSCLP. We analyzed five SNPs (rs64466931c.-425G> T/c.-35G>A/rs3775261/rs12532) located from 6.3 kb upstream to 3' UTR in a sample of 150 unrelated NSCLP case-parent trios. Four haplotypes showed overtransmission from parents to affected progeny, but individual SNPs did not. Two haplotypes presented allele combination C-G-A-G (P=0.035) and two T-G-C-A (P=0.044) (SNP order rs64466931c.-35G>A/rs3775261/rs12532). The rs12532 A allele had a 2.08-fold increase in the risk of NSCLP when inherited from the father (95% CI: 1.10-4.02; P=0.025), but not from the mother. These results could indicate epigenetic control by imprinting in the role of MSX1 in NSCLP. Different authors have proposed that some genes that play a role in NSCLP depend on parental origin. Our findings and those previously reported by our group show that a variety of factors appears to be involved in the association between MSX1 and NSCLP. The full mechanism of MSX1 in the development of NSCLP has not been fully understood. (C) 2010 Wiley-Liss, Inc.
- ItemPrevalence of Helicobacter pylori Antimicrobial Resistance Among Chilean Patients(2021) Gonzalez-Hormazabal, Patricio; Arenas, Alex; Serrano, Carolina; Pizarro, Margarita; Fuentes-Lopez, Eduardo; Arnold, Jorge; Berger, Zoltan; Musleh, Maher; Valladares, Hector; Lanzarini, Enrique; Jara, Lilian; Castro, V. Gonzalo; Camargo, M. Constanza; Riquelme, ArnoldoBackground. Treatments for Helicobacter pylori (H. pylori) eradication include the use of antibiotics and a proton-pump inhibitor. Antibiotic resistance is a major concern for two drugs: levofloxacin and clarithromycin. The aim was to determine the prevalence of levofloxacin resistance (LevoR) and clarithromycin resistance (ClaR) in an urban population in Santiago, Chile.
- ItemThe BARD1 Cys557Ser variant and risk of familial breast cancer in a South-American population(2012) Gonzalez-Hormazabal, Patricio; Reyes, José M.; Blanco, Rafael; Bravo, Teresa; Carrera, Ignacio; Peralta, Octavio; Gómez, Fernando; Waugh, Enrique; Margarit, Sonia; Ibañez, Gladys; Santos Martín, José Luis; Jara, LilianSince the discovery of the BRCA1 and BRCA2 genes, much work has been carried out to identify further breast cancer (BC) susceptibility genes. BARD1 (BRCA1-associated ring domain) was originally identified as a BRCA1-interacting protein but has also been described in tumor-suppressive functions independent of BRCA1. Some association studies have suggested that the BARD1 Cys557Ser variant might be associated with increased risk of BC, but others have failed to confirm this finding. To date, this variant has not been analyzed in Spanish or South-American populations. In this study, using a case-control design, we analyzed the C-terminal Cys557Ser change in 322 Chilean BC cases with no mutations in BRCA1 or BRCA2 and in 570 controls in order to evaluate its possible association with BC susceptibility. BARD1 Cys557Ser was associated with an increased BC risk (P = 0.04, OR = 3.4 [95 % CI 1.2-10.2]) among cases belonging to families with a strong family history of BC. No difference between single cases affected with age < 50 years at diagnosis (n = 117) and controls was observed for carriers of Cys/Ser genotype. It is likely that this variant is not involved in BC risk in this group of women. We also analyzed a possible interaction between BARD1 557Ser/XRCC3 241Met variants considering the role of both genes in the maintenance of genome integrity. The combined genotype Cys/Ser-carrier with the XRCC3 241Met allele was associated with an increased BC risk (P = 0.02, OR = 5.01 [95 % CI 1.36-18.5]) among women belonging to families with at least three BC and/or ovarian cancer cases. Our results suggest that BARD1 557Ser and XRCC3 241Met may play roles in BC risk in women with a strong family history of BC. Nevertheless there is no evidence of an interaction between the two SNPs. These findings should be confirmed by other studies and in other populations.