GUILHERME FRANCISCO
Projetos de Pesquisa
Unidades Organizacionais
LIM/24 - Laboratório de Oncologia Experimental, Hospital das Clínicas, Faculdade de Medicina
9 resultados
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- European ancestry and polymorphisms in DNA repair genes modify the risk of melanoma: A case-control study in a high UV index region in Brazil(2011) GONCALVES, Fernanda T.; FRANCISCO, Guilherme; SOUZA, Sonia P. de; LUIZ, Olinda C.; FESTA-NETO, Cyro; SANCHES, Jose A.; CHAMMAS, Roger; GATTAS, Gilka J. F.; ELUF-NETO, JoseBackground: UV radiation is the major environmental factor related to development of cutaneous melanoma. Besides sun exposure and the influence of latitude, some host characteristics such as skin phototype and hair and eye color are also risk factors for melanoma. Polymorphisms in DNA repair genes could be good candidates for susceptibility genes, mainly in geographical regions exposed to high solar radiation. Objective: Evaluate the role of host characteristic.; and DNA repair polymorphism in melanoma risk in Brazil. Methods: We carried out a hospital-based case-control study in Brazil to evaluate the contribution of host factors and polymorphisms in DNA repair to melanoma risk. A total of 412 patients (202 with melanoma and 210 controls) were analyzed regarding host characteristics for melanoma risk as well as for 11 polymorphisms in DNA repair genes. Results: We found an association of host characteristics with melanoma development, such as eye and hair color, fair skin, history of pigmented lesions removed, sunburns in childhood and adolescence, and also European ancestry. Regarding DNA repair gene polymorphisms, we found protection for the XPG 1104 His/His genotype (OR 0.32; 95% CI 0.13-0.75), and increased risk for three polymorphisms in the XPC gene (PAT+; IV-6A and 939Gln), which represent a haplotype for XPC. Melanoma risk was higher in individuals carrying the complete XPC haplotype than each individual polymorphism (OR 3.64; 95% CI 1.77-7.48). Conclusions: Our data indicate that the host factors European ancestry and XPC polymorphisms contributed to melanoma risk in a region exposed to high sun radiation.
- Arg72Pro TP53 polymorphism and cancer susceptibility: a comprehensive meta-analysis of 302 case-control studies(2011) FRANCISCO, Guilherme; MENEZES, Paulo Rossi; ELUF-NETO, Jose; CHAMMAS, RogerArg72Pro is a common polymorphism in TP53, showing differences in its biological functions. Case-control studies have been performed to elucidate the role of Arg72Pro in cancer, although the results are conflicting and heterogeneous. Here, we analyzed pooled data from case-control studies to determine the role of Arg72Pro in different cancer sites. We performed a systematic review and meta-analysis of 302 case-control studies that analyzed Arg72Pro in cancer susceptibility. Odds ratios were estimated for different tumor sites using distinct genetic models, and the heterogeneity between studies was explored using I(2) values and meta-regression. We adopted quality criteria to classify the studies. Subgroup analyses were done for tumor sites according to ethnicity, histological, and anatomical sites. Results indicated that Arg72Pro is associated with higher susceptibility to cancer in some tumor sites, mainly hepatocarcinoma. For some tumor sites, quality of studies was associated with the size of genetic association, mainly in cervical, head and neck, gastric, and lung cancer. However, study quality did not explain the observed heterogeneity substantially. Meta-regression showed that ethnicity, allelic frequency and genotyping method were responsible for a substantial part of the heterogeneity observed. Our results suggest ethnicity and histological and anatomical sites may modulate the penetrance of Arg72Pro in cancer susceptibility. This meta-analysis denotes the importance for more studies with good quality and that the covariates responsible for heterogeneity should be controlled to obtain a more conclusive response about the function of Arg72Pro in cancer.
- O-glycan sialylation alters galectin-3 subcellular localization and decreases chemotherapy sensitivity in gastric cancer(2016) SANTOS, Sofia N.; JUNQUEIRA, Mara S.; FRANCISCO, Guilherme; VILANOVA, Manuel; MAGALHAES, Ana; BARUFFI, Marcelo Dias; CHAMMAS, Roger; HARRIS, Adrian L.; REIS, Celso A.; BERNARDES, Emerson S.ST6GalNAc-I, the sialyltransferase responsible for sialyl-Tn (sTn) synthesis, has been previously reported to be positively associated with cancer aggressiveness. Here we describe a novel sTn-dependent mechanism for chemotherapeutic resistance. We show that sTn protects cancer cells against chemotherapeutic-induced cell death by decreasing the interaction of cell surface glycan receptors with galectin-3 and increasing its intracellular accumulation. Moreover, exogenously added galectin-3 potentiated the chemotherapeutics-induced cytotoxicity in sTn non-expressing cells, while sTn overexpressing cells were protected. We also found that the expression of sTn was associated with a reduction in galectin-3-binding sites in human gastric samples tumors. ST6GalNAc-I knockdown restored galectin-3-binding sites on the cell surface and chemotherapeutics sensibility. Our results clearly demonstrate that an interruption of O-glycans extension caused by ST6GalNAc-I enzymatic activity leads to tumor cells resistance to chemotherapeutic drugs, highlighting the need for the development of novel strategies to target galectin-3 and/or ST6GalNAc-I.
- Ethnicity and Cutaneous Melanoma in the City of Sao Paulo, Brazil: A Case-Control Study(2012) LUIZ, Olinda C.; GIANINI, Reinaldo Jose; GONCALVES, Fernanda T.; FRANCISCO, Guilherme; FESTA-NETO, Cyro; SANCHES, Jose Antonio; GATTAS, Gilka J. F.; CHAMMAS, Roger; ELUF-NETO, JoseBackground: Over the last century the incidence of cutaneous melanoma has increased worldwide, a trend that has also been observed in Brazil. The identified risk factors for melanoma include the pattern of sun exposure, family history, and certain phenotypic features. In addition, the incidence of melanoma might be influenced by ethnicity. Like many countries, Brazil has high immigration rates and consequently a heterogenous population. However, Brazil is unique among such countries in that the ethnic heterogeneity of its population is primarily attributable to admixture. This study aimed to evaluate the contribution of European ethnicity to the risk of cutaneous melanoma in Brazil. Methodology/Principal Findings: We carried out a hospital-based case-control study in the metropolitan area of Sao Paulo, Brazil. We evaluated 424 hospitalized patients (202 melanoma patients and 222 control patients) regarding phenotypic features, sun exposure, and number of grandparents born in Europe. Through multivariate logistic regression analysis, we found the following variables to be independently associated with melanoma: grandparents born in Europe-Spain (OR = 3.01, 95% CI: 1.03-8.77), Italy (OR = 3.47, 95% CI: 1.41-8.57), a Germanic/Slavic country (OR = 3.06, 95% CI: 1.05-8.93), or >= 2 European countries (OR = 2.82, 95% CI: 1.06-7.47); eye color-light brown (OR = 1.99, 95% CI: 1.14-3.84) and green/blue (OR = 4.62; 95% CI 2.22-9.58); pigmented lesion removal (OR = 3.78; 95% CI: 2.21-6.49); no lifetime sunscreen use (OR = 3.08; 95% CI: 1.03-9.22); and lifetime severe sunburn (OR = 1.81; 95% CI: 1.03-3.19). Conclusions: Our results indicate that European ancestry is a risk factor for cutaneous melanoma. Such risk appears to be related not only to skin type, eye color, and tanning capacity but also to others specific characteristics of European populations introduced in the New World by European immigrants.
bookPart Biologia molecular dos melanomas(2013) FRANCISCO, Guilherme; OTAKE, Andréia Hanada; SAITO, Renata de Freitas; CHAMMAS, Roger- Association between the p27 rs2066827 variant and tumor multiplicity in patients harboring MEN1 germline mutations(2014) LONGUINI, Viviane C.; LOURENCO JR., Delmar M.; SEKIYA, Tomoko; MEIRELLES, Osorio; GONCALVES, Tatiana D.; COUTINHO, Flavia L.; FRANCISCO, Guilherme; OSAKI, Luciana H.; CHAMMAS, Roger; ALVES, Venancio A. F.; SIQUEIRA, Sheila A. C.; SCHLESINGER, David; NASLAVSKY, Michel S.; ZATZ, Mayana; DUARTE, Yeda A. O.; LEBRAO, Maria Lucia; GAMA, Patricia; LEE, Misu; MOLATORE, Sara; PEREIRA, Maria Adelaide A.; JALLAD, Raquel S.; BRONSTEIN, Marcello D.; CUNHA-NETO, Malebranche B.; LIBERMAN, Bernardo; FRAGOSO, Maria Candida B. V.; TOLEDO, Sergio P. A.; PELLEGATA, Natalia S.; TOLEDO, Rodrigo A.Objective: To date, no evidence of robust genotype-phenotype correlation or disease modifiers for multiple endocrine neoplasia type 1 (MEN1) syndrome has been described, leaving the highly variable clinical presentation of patients unaccounted for. Design: As the CDKN1B (p27) gene causes MEN4 syndrome and it is transcriptionally regulated by the product of the MEN1 gene (menin), we sought to analyze whether p27 influences the phenotype of MEN1-mutated patients. The cohort consisted of 100 patients carrying germline MEN1 gene mutations and 855 population-matched control individuals. Methods: Genotyping of the coding p27 c.326T>G (V109G) variant was performed by sequencing and restriction site digestion, and the genotypes were associated with clinical parameters by calculating odds ratios (ORs) and their 95% CIs using logistic regression. Results: There were significant differences in p27 V109G allele frequencies between controls and MEN1-mutated patients (OR=2.55, P=0.019, CI=1.013-5.76). Among patients who are >= 30 years old carrying truncating MEN1 mutations, the T allele was strongly associated with susceptibility to tumors in multiple glands (three to four glands affected vs one to two glands affected; OR=18.33; P=0.002, CI=2.88-16.41). This finding remained significant after the Bonferroni's multiple testing correction, indicating a robust association. No correlations were observed with the development of MEN1-related tumors such as hyperparathyroidism, pituitary adenomas, and enteropancreatic and adrenocortical tumors. Conclusions: Our study suggests that the p27 tumor suppressor gene acts as a disease modifier for the MEN1 syndrome associated with MEN1 germline mutations. If confirmed in independent patient cohorts, this finding could facilitate the management of this clinically complex disease.
- Polymorphisms in the p27(kip-1) and prohibitin genes denote novel genes associated with melanoma risk in Brazil, a high ultraviolet index region(2013) FRANCISCO, Guilherme; GONCALVES, Fernanda T.; LUIZ, Olinda C.; SAITO, Renata F.; TOLEDO, Rodrigo A.; SEKIYA, Tomoko; TORTELLI JR., Tharcisio C.; VIOLLA, Esther D. V. B.; MAZZOTTI, Tatiane K. Furuya; CIRILO, Priscila D. R.; FESTA-NETO, Cyro; SANCHES, Jose A.; GATTAS, Gilka J. F.; ELUF-NETO, Jose; CHAMMAS, RogerUltraviolet (UV) radiation is a major environmental risk factor to the development of cutaneous melanoma as it induces pyrimidine dimers in DNA. Genes that exert their function by arresting the cell cycle are critical to avoid carcinogenic mutations, allowing the processing of DNA repair systems. This study was carried out to evaluate the role of polymorphisms in cell cycle genes such as TP53, p27(kip-1), CDKN2A, prohibitin, and GADD153 in melanoma risk as well as their influence on known risk factors in a high UV index region. A hospital-based case-control study was carried out in Brazil to evaluate the contribution of polymorphisms in cell cycle genes toward melanoma risk. The study comprised 202 melanoma patients and 210 controls. The polymorphisms analyzed were TP53 Arg72Pro, p27(kip-1) Val109Gly, GADD153 Phe10Phe (rs697221), CDKN2A 3 ' UTR C540G, and prohibitin 3 ' UTR C1703T. As regards, p27(kip-1) Val109Gly, both heterozygous and homozygous Gly genotypes were shown to be protective genotypes on calculating both crude and adjusted odds ratios (ORs) for age, sex, and educational level [OR 0.37; 95% confidence interval (CI) 0.16-0.87; P < 0.05]. Similarly, the prohibitin TT genotype increased melanoma risk in the crude and adjusted analyses (OR 2.40; 95% CI 1.10-5.26; P < 0.05). The p27(kip-1) Gly protective genotype decreased the risk for melanoma in a stratified analysis of the known risk factors such as hair and eye color, sunburns, pigmented lesions, and European ancestry. The prohibitin TT genotype increased the risk of melanoma by such host factors. Our results showed for the first time that polymorphisms in p27(kip-1) Val109Gly and in prohibitin 3 ' UTR C1703T genotypes modulate the risk to melanoma in a high UV index region. Melanoma Res 23: 231-236 (C) 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins.
- p27 variant and corticotropinoma susceptibility: a genetic and in vitro study(2014) SEKIYA, Tomoko; BRONSTEIN, Marcello D.; BENFINI, Katiuscia; LONGUINI, Viviane C.; JALLAD, Raquel S.; MACHADO, Marcio C.; GONCALVES, Tatiana D.; OSAKI, Luciana H.; HIGASHI, Leonardo; VIANA- JR., Jose; KATER, Claudio; LEE, Misu; MOLATORE, Sara; FRANCISCO, Guilherme; CHAMMAS, Roger; NASLAVSKY, Michel S.; SCHLESINGER, David; GAMA, Patricia; DUARTE, Yeda A. O.; LEBRAO, Maria Lucia; ZATZ, Mayana; MEIRELLES, Osorio; LIBERMAN, Bernardo; FRAGOSO, Maria Candida B. V.; TOLEDO, Sergio P. A.; PELLEGATA, Natalia S.; TOLEDO, Rodrigo A.Germline mutations in p27(kip1) are associated with increased susceptibility to multiple endocrine neoplasias (MEN) both in rats and humans; however, the potential role of common polymorphisms of this gene in endocrine tumor susceptibility and tumorigenesis remains mostly unrecognized. To assess the risk associated with polymorphism rs2066827 (p27-V109G), we genotyped a large cohort of Brazilian patients with sporadic endocrine tumors (pituitary adenomas, n=252; pheochromocytomas, n=125; medullary thyroid carcinoma, n=51; and parathyroid adenomas, n=19) and 885 population- matched healthy controls and determined the odds ratios and 95% CIs. Significant associations were found for the group of patients with pituitary adenomas (P=0.01), particularly for those with ACTH-secreting pituitary adenomas (P=0.005). In contrast, no association was found with GH- secreting pituitary tumors alone or with the sporadic counterpart of MEN2- component neoplasias. Our in vitro analyses revealed increased colony formation and cell growth rate for an AtT20 corticotropin mouse cell line overexpressing the p27- V109G variant compared with cells transfected with the WT p27. However, the genotypic effects in genetic and in vitro approaches were divergent. In accordance with our genetic data showing specificity for ACTH- secreting pituitary tissues, the overexpression of p27-V109G in a GH3 somatotropin rat cell line resulted in no difference compared with the WT. Pituitary tumors are one of the major clinical components of syndromes associated with the p27 pathogenic mutations MENX and MEN4. Our genetic and in vitro data indicate that the common polymorphism rs2066827 may play a role in corticotropinoma susceptibility and tumorigenesis through a molecular mechanism not fully understood thus far.
- Predominant role of DNA polymerase eta and p53-dependent translesion synthesis in the survival of ultraviolet-irradiated human cells(2017) LERNER, Leticia K.; FRANCISCO, Guilherme; SOLTYS, Daniela T.; ROCHA, Clarissa R. R.; QUINET, Annabel; VESSONI, Alexandre T.; CASTRO, Ligia P.; DAVID, Taynah I. P.; BUSTOS, Silvina O.; STRAUSS, Bryan E.; GOTTIFREDI, Vanesa; STARY, Anne; SARASIN, Alain; CHAMMAS, Roger; MENCK, Carlos F. M.Genome lesions trigger biological responses that help cells manage damaged DNA, improving cell survival. Pol eta is a translesion synthesis (TLS) polymerase that bypasses lesions that block replicative polymerases, avoiding continued stalling of replication forks, which could lead to cell death. p53 also plays an important role in preventing cell death after ultraviolet (UV) light exposure. Intriguingly, we show that p53 does so by favoring translesion DNA synthesis by pol eta. In fact, the p53-dependent induction of pol eta in normal and DNA repair-deficient XP-C human cells afterUV exposure has a protective effect on cell survival after challenging UV exposures, which was absent in p53-and Pol H-silenced cells. Viability increase was associated with improved elongation of nascent DNA, indicating the protective effect was due to more efficient lesion bypass by pol eta. This protection was observed in cells proficient or deficient in nucleotide excision repair, suggesting that, from a cell survival perspective, proper bypass of DNA damage can be as relevant as removal. These results indicate p53 controls the induction of pol eta in DNA damaged human cells, resulting in improved TLS and enhancing cell tolerance to DNA damage, which parallels SOS responses in bacteria.