Browsing by Author "Aguayo González, Francisco"

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    High frequency of p 16 promoter methylation in non-small cell lung carcinomas from Chile
    (2007) Guzman, Leda M.; Koriyama, Chihaya; Akiba, Suminori; Eizuru, Yoshito; Castillo, Darwins; Corvalán R., Alejandro; Aguayo González, Francisco
    The inactivation of tumour suppressor genes by aberrant methylation of promoter regions has been described as a frequent event in neoplasia development, including lung cancer. The p16 gene is a tumour suppressor gene involved in the regulation of cell cycle progression that has been reported to be inactivated by promoter methylation in lung carcinomas at variable frequencies around the world in a smoking habit dependent manner. The purpose of this study was to investigate the methylation status of the promoter region of the p16 gene in 74 non-small cell lung carcinomas from Chile. The frequency of p16 gene inactivation by promoter methylation was determined as 79.7% (59/74). When we considered histological type, we observed that p16 promoter methylation was significantly higher in squamous cell carcinomas (30/33, 91%) compared with adenocarcinomas (21/30, 70%) (p=0.029). In addition, no association between p16 promoter methylation and gender, age or smoking habit was found (p=0.202, 0.202 and 0.147 respectively). Our results suggest that p16 promoter hypermethylation is a very frequent event in non-small cell lung carcinomas from Chile and could be smoking habit-independent.
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    Human Papillomavirus 16 E7 Promotes EGFR/PI3K/AKT1/NRF2 Signaling Pathway Contributing to PIR/NF-kappa B Activation in Oral Cancer Cells
    (2020) Carrillo Beltrán, D.; Muñoz, J. P.; Guerrero Vásquez, N.; Blanco, R.; León, O.; Lino, V. D.; Tapia, J. C.; Maldonado, E.; Corvalán R., Alejandro; Aguayo González, Francisco; Dubois Camacho, K.; Hermoso, M. A.; Calaf, G. M.; Boccardo, E.
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    Human papillomavirus and Epstein-Barr virus infections in breast cancer from chile
    (2011) Padilla, Oslando; Solís, Luisa.; Corvalán R., Alejandro; Aguayo González, Francisco; Khan, Noureen.; Koriyama, Chihaya.; González, Carolina; Ampuero, Sandra.; Eizuru, Yoshito.; Akiba, Suminori.
    Abstract Background Human papillomavirus (HPV) and Epstein Barr virus (EBV) have been found in breast carcinomas (BCs) around the world. In this study, fifty-five BCs from Chile were analyzed for HPV and EBV presence. In addition, HPV-16 viral load/physical status and E6/E7 expressions were determined. Results The amplification of a housekeeping gene showed that 46/55 samples (84%) had amplifiable DNA. HPV-16 was detected in 4/46 BCs (8.7%) and EBV was detected in 3/46 (6.5%) BCs. The analysis of HPV-16 physical status showed that this virus was integrated in all of the tumors with a relatively low viral load (range: 0.14 to 33.8 copies/cell). E6 and E7 transcripts, however, were not detected in any HPV-16 positive specimens. Using a Cox-regression model, we found a statistically significant association between EBV presence and poor survival (p = 0.013). Conclusions The findings in this study suggest that it is unlikely that HPV and/or EBV play a direct role in the etiology of BC.Abstract Background Human papillomavirus (HPV) and Epstein Barr virus (EBV) have been found in breast carcinomas (BCs) around the world. In this study, fifty-five BCs from Chile were analyzed for HPV and EBV presence. In addition, HPV-16 viral load/physical status and E6/E7 expressions were determined. Results The amplification of a housekeeping gene showed that 46/55 samples (84%) had amplifiable DNA. HPV-16 was detected in 4/46 BCs (8.7%) and EBV was detected in 3/46 (6.5%) BCs. The analysis of HPV-16 physical status showed that this virus was integrated in all of the tumors with a relatively low viral load (range: 0.14 to 33.8 copies/cell). E6 and E7 transcripts, however, were not detected in any HPV-16 positive specimens. Using a Cox-regression model, we found a statistically significant association between EBV presence and poor survival (p = 0.013). Conclusions The findings in this study suggest that it is unlikely that HPV and/or EBV play a direct role in the etiology of BC.
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    Human papillomavirus-16 presence and physical status in lung carcinomas from Asia
    (2010) Aguayo González, Francisco; Anwar, Muhammad.; Koriyama, Chihaya.; Castillo, Andres.; Sun, Quanfu.; Morewaya, Jacob.; Eizuru, Yoshito.; Akiba, Suminori.
    Abstract Background Although human papillomavirus (HPV) genome has been detected in lung cancer, its prevalence is highly variable around the world. Higher frequencies have been reported in far-east Asian countries, when compared with European countries. The present study analysed the HPV-16 presence in 60 lung carcinomas from the Asian countries China, Pakistan and Papua New Guinea. Results HPV-16 was present in 8/59 (13%) samples. According to histological type, HPV-16 was detected in 8/18 (44%) squamous cell carcinomas (SQCs), which were mainly from Pakistan; 0/38 (0%) adenocarcinomas (ACs), which were mainly from China; and in 0/4 (0%) small cell carcinomas (SCLCs). The observed histological difference was statistically significant (p < 0.001). HPV-16 viral load was also determined using real-time polymerase chain reaction (qRT-PCR); it ranged between 411 to 2345 copies/100 ng of genomic DNA. HPV-16 genome was found integrated into the host genome in every HPV-16 positive carcinoma. Conclusion These results support the notion that HPV-16 infection is highly associated with SQCs in Pakistan. Our results show a frequent HPV-16 integration in SQCs, although the low viral load casts doubt respect a direct etiological role of HPV in lung carcinomas from Asia. Additional HPV-16 characterization is necessary to establish a direct or indirect etiological role of HPV in this malignancy.
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    Interplay between Epstein-Barr virus infection and environmental xenobiotic exposure in cancer
    (2021) Aguayo González, Francisco; Boccardo, Enrique; Corvalán R., Alejandro; Calaf, Gloria M.; Blanco, Rancés
    Abstract Epstein-Barr virus (EBV) is a herpesvirus associated with lymphoid and epithelial malignancies. Both B cells and epithelial cells are susceptible and permissive to EBV infection. However, considering that 90% of the human population is persistently EBV-infected, with a minority of them developing cancer, additional factors are necessary for tumor development. Xenobiotics such as tobacco smoke (TS) components, pollutants, pesticides, and food chemicals have been suggested as cofactors involved in EBV-associated cancers. In this review, the suggested mechanisms by which xenobiotics cooperate with EBV for carcinogenesis are discussed. Additionally, a model is proposed in which xenobiotics, which promote oxidative stress (OS) and DNA damage, regulate EBV replication, promoting either the maintenance of viral genomes or lytic activation, ultimately leading to cancer. Interactions between EBV and xenobiotics represent an opportunity to identify mechanisms by which this virus is involved in carcinogenesis and may, in turn, suggest both prevention and control strategies for EBV-associated cancers.
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    Loss of Expression of Reprimo, a p53-induced Cell Cycle Arrest Gene, Correlates with Invasive Stage of Tumor Progression and p73 Expression in Gastric Cancer
    (2015) Saavedra, K.; Valbuena Mora, José Rafael; Olivares, W.; Marchant, M.; Rodríguez, A.; Torres, V.; Carrasco, G.; Gúzman, L.; Aguayo González, Francisco; Roa Strauch, Juan Carlos Enrique; Corvalán R., Alejandro
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    Three Prime Repair Exonuclease 1 (TREX1) expression correlates with cervical cancer cells growth in vitro and disease progression in vivo
    (2019) Prati, Bruna; Abjaude, Walason da Silva; Termini, Lara; Morale, Mirian; Herbster, Suellen; Aguayo González, Francisco; Longatto-Filho, Adhemar; Nunes, Rafaella Almeida Lima; Córdoba Camacho, Lizeth Carolina; Rabelo-Santos, Silvia Helena; Zeferino, Luiz Carlos; Boccardo, Enrique
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    Upregulation of PIR gene expression induced by human papillomavirus E6 and E7 in epithelial oral and cervical cells
    (2017) Carrillo, Diego; Muñoz, Juan P.; Huerta, Hernán; Leal, Gabriel; Corvalán R., Alejandro; León, Oscar; Calaf, Gloria M.; Urzúa, Ulises; Boccardo, Enrique; Aguayo González, Francisco