Browsing by Author "Riquelme, Ismael"

Now showing 1 - 16 of 16
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    Activated status of Hedgehog pathway in oral squamous cell carcinoma (OSCC): the door is still open
    (Ame Publ Co, 2016) Riquelme, Ismael; Roa Strauch Juan Carlos Enrique
    The Hedgehog (Hh) signaling pathway is essential for regulation of cell differentiation and organ formation in a concentration-dependent manner during embryonic development. Also, this pathway is important to the maintenance of adult stem cells. Studies have shown that three members of this family are present in mammals: Sonic hedgehog (SHH), Desert hedgehog (DHH) and Indian hedgehog (IHH), all of which encode secreted proteins (1).
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    Assessment of Gastritis and Gastric Cancer Risk in the Chilean Population Using the OLGA System
    (2019) Bellolio, Enrique; Riquelme, Ismael; Riffo Campos, Angela L.; Rueda, Carlos; Ferreccio Readi, Catterina; Villaseca, Miguel; Brebi, Priscilla; Muñoz, Sergio R.; Araya, Juan Carlos
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    Correction to : MicroRNA‑335‑5p is a potential suppressor of metastasis and invasion in gastric cancer
    (2021) Sandoval Bórquez, Alejandra; Polakovicova, Iva; Carrasco Véliz, Nicolás; Lobos González, Lorena; Riquelme, Ismael; Carrasco Avino, Gonzalo; Bizama, Carolina; Norero Muñoz, Enrique; Owen, Gareth Ivor; Roa Strauch, Juan Carlos Enrique; Corvalán R., Alejandro
    An amendment to this paper has been published and can be accessed via the original article.
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    Environmental and Lifestyle Risk Factors in the Carcinogenesis of Gallbladder Cancer
    (2022) Pérez Moreno, Pablo; Riquelme, Ismael; García Cañete, Patricia; Brebi, Priscilla; Roa, Juan Carlos
    Gallbladder cancer (GBC) is an aggressive neoplasm that in an early stage is generally asymptomatic and, in most cases, is diagnosed in advanced stages with a very low life expectancy because there is no curative treatment. Therefore, understanding the early carcinogenic mechanisms of this pathology is crucial to proposing preventive strategies for this cancer. The main risk factor is the presence of gallstones, which are associated with some environmental factors such as a sedentary lifestyle and a high-fat diet. Other risk factors such as autoimmune disorders and bacterial, parasitic and fungal infections have also been described. All these factors can generate a long-term inflammatory state characterized by the persistent activation of the immune system, the frequent release of pro-inflammatory cytokines, and the constant production of reactive oxygen species that result in a chronic damage/repair cycle, subsequently inducing the loss of the normal architecture of the gallbladder mucosa that leads to the development of GBC. This review addresses how the different risk factors could promote a chronic inflammatory state essential to the development of gallbladder carcinogenesis, which will make it possible to define some strategies such as anti-inflammatory drugs or public health proposals in the prevention of GBC.
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    Epigallocatechin Gallate Enhances MAL-PDT Cytotoxic Effect on PDT-Resistant Skin Cancer Squamous Cells
    (2020) Leon, Daniela; Buchegger, Kurt; Silva, Ramon; Riquelme, Ismael; Viscarra, Tamara; Mora-Lagos, Barbara; Zanella, Louise; Schafer, Fabiola; Kurachi, Cristina; Roa, Juan Carlos; Ili, Carmen; Brebi, Priscilla
    Photodynamic therapy (PDT) has been used to treat certain types of non-melanoma skin cancer with promising results. However, some skin lesions have not fully responded to this treatment, suggesting a potential PDT-resistant phenotype. Therefore, novel therapeutic alternatives must be identified that improve PDT in resistant skin cancer. In this study, we analyzed the cell viability, intracellular protoporphyrin IX (PpIX) content and subcellular localization, proliferation profile, cell death, reactive oxygen species (ROS) detection and relative gene expression in PDT-resistant HSC-1 cells. PDT-resistant HSC-1 cells show a low quantity of protoporphyrin IX and low levels of ROS, and thus a low rate of death cell. Furthermore, the resistant phenotype showed a downregulation of HSPB1, SLC15A2, FECH, SOD2 and an upregulation of HMBS and BIRC5 genes. On the other hand, epigallocatechin gallate catechin enhanced the MAL-PDT effect, increasing levels of protoporphyrin IX and ROS, and killing 100% of resistant cells. The resistant MAL-PDT model of skin cancer squamous cells (HSC-1) is a reliable and useful tool to understand PDT cytotoxicity and cellular response. These resistant cells were successfully sensitized with epigallocatechin gallate catechin. The in vitro epigallocatechin gallate catechin effect as an enhancer of MAL-PDT in resistant cells is promising in the treatment of difficult skin cancer lesions.
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    Evaluation of DNA methylation in promoter regions of SFRP4 and ZAR1 in urine and plasma of women with cervical lesions
    (2017) Hoffstetter, Rene; Riquelme, Ismael; Andana, Alejandra; Ili, Carmen G.; Buchegger, Kurt; Vargas, Hernan; Brebi, Priscilla; Roa Strauch, Juan Carlos Enrique
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    Exploring the Genetic Diversity of Epstein–Barr Virus among Patients with Gastric Cancer in Southern Chile
    (2023) Reyes, María Elena; Zanella, Louise; Riquelme, Ismael; Buchegger, Kurt; Mora-Lagos, Bárbara; Guzmán, Pablo; García Cañete, Patricia; Roa Strauch, Juan Carlos Enrique; Gloria Ili, Carmen; Brebi, Priscilla
    The Epstein–Barr virus (EBV) has been associated with gastric cancer (GC), one of the deadliest malignancies in Chile and the world. Little is known about Chilean EBV strains. This study aims to investigate the frequency and genetic diversity of EBV in GC in patients in southern Chile. To evaluate the prevalence of EBV in GC patients from the Chilean population, we studied 54 GC samples using the gold standard detection method of EBV-encoded small RNA (EBER). The EBV-positive samples were subjected to amplification and sequencing of the Epstein–Barr virus nuclear protein 3A (EBNA3A) gene to evaluate the genetic diversity of EBV strains circulating in southern Chile. In total, 22.2% of the GC samples were EBV-positive and significantly associated with diffuse-type histology (p = 0.003). Phylogenetic analyses identified EBV-1 and EBV-2 in the GC samples, showing genetic diversity among Chilean isolates. This work provides important information for an epidemiological follow-up of the different EBV subtypes that may cause GC in southern Chile.
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    Immunohistochemical Expression of Vascular Endothelial Growth Factor A in Advanced Gallbladder Carcinoma
    (2014) Letelier, Pablo; García Cañete, Patricia; Leal, Pamela; Ili, Carmen; Buchegger, Kurt; Riquelme, Ismael; Sandoval, Alejandra; Tapia, Oscar; Roa Strauch, Juan Carlos Enrique
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    LINC00662 Promotes Aggressive Traits by Modulating OCT4 Expression through miR-335-5p in Gallbladder Cancer Cells
    (MDPI, 2024) Perez-Moreno, Pablo; Riquelme, Ismael; Bizama Soto, Carolina Del Carmen; Vergara-Gomez, Luis; Tapia, Julio C.; Brebi, Priscilla; Garcia Canete, Patricia Del Carmen; Roa Strauch, Juan Carlos Enrique
    Long non-coding RNAs (lncRNAs) are nucleotide sequences that participate in different biological processes and are associated with different pathologies, including cancer. Long intergenic non-protein-coding RNA 662 (LINC00662) has been reported to be involved in different cancers, including colorectal, prostate, and breast cancer. However, its role in gallbladder cancer has not yet been described. In this article, we hypothesize that LINC00662 has an important role in the acquisition of aggressiveness traits such as a stem-like phenotype, invasion, and chemoresistance in gallbladder cancer. Here, we show that LINC00662 is associated with larger tumor size and lymph node metastasis in patients with gallbladder cancer. Furthermore, we show that the overexpression of LINC00662 promotes an increase in CD133+/CD44+ cell populations and the expression of stemness-associated genes. LINC00662 promotes greater invasive capacity and the expression of genes associated with epithelial-mesenchymal transition. In addition, the expression of LINC00662 promotes resistance to cisplatin and 5-fluorouracil, associated with increased expression of chemoresistance-related ATP-binding cassette (ABC) transporters in gallbladder cancer (GBC) cell lines. Finally, we show that the mechanism by which LINC00662 exerts its function is through a decrease in microRNA 335-5p (miR-335-5p) and an increase in octamer-binding transcription factor 4 (OCT4) in GBC cells. Thus, our data allow us to propose LINC00662 as a biomarker of poor prognosis and a potential therapeutic target for patients with GBC.
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    Rapamycin and WYE-354 suppress human gallbladder cancer xenografts in mice
    (2015) Weber, Helga; Leal, Pamela; Stein, Stefan; Kunkel, Hana; García Cañete, Patricia; Bizama, Carolina; Espinoza, Jaime A.; Riquelme, Ismael; Nervi Nattero, Bruno; Araya, Juan C.; Grez, Manuel; Roa Strauch, Juan Carlos Enrique
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    Reprimo, a Potential p53-Dependent Tumor Suppressor Gene, Is Frequently Hypermethylated in Estrogen Receptor α-Positive Breast Cancer
    (2017) Buchegger, Kurt; Riquelme, Ismael; Viscarra, Tamara; Ili, Carmen; Brebi, Priscilla; Hui-Ming Huang, Tim; Roa Strauch, Juan Carlos Enrique
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    Small molecule inhibitor screening identifified HSP90 inhibitor 17-AAG as potential therapeutic agent for gallbladder cancer
    (2017) Weber, Helga; Valbuena Mora, José Rafael; Barbhuiya, Mustafa A.; Stein, Stefan; Kunkel, Hana; García Muñoz, Patricia; Bizama, Carolina; Riquelme, Ismael; Espinoza, Jaime A.; Kurtz, Stephen E.; Tyner, Jeffrey W.; Calderon, Juan Francisco; Corvalán R., Alejandro; Grez, Manuel; Pandey, Akhilesh; Leal Rojas, Pamela; Roa Strauch, Juan Carlos Enrique
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    The conundrum of the Epstein-Barr virus-associated gastric carcinoma in the Americas
    (2017) Carrasco Avino, Gonzalo; Riquelme, Ismael; Padilla, Oslando; Villaseca, Miguel; Aguayo González, Francisco; Corvalán R., Alejandro
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    The Emerging Role of PIWI-Interacting RNAs (piRNAs) in Gastrointestinal Cancers: An Updated Perspective
    (2022) Riquelme, Ismael; Perez Moreno, Pablo; Letelier, Pablo; Brebi, Priscilla; Roa, Juan Carlos
    Simple Summary Gastrointestinal (GI) cancers are high mortality malignancies due to late diagnosis, the presence of metastasis and drug resistance development. Novel and more reliable biomarkers and therapeutic targets are still needed for these diseases. PIWI-interacting RNAs (piRNAs) are small transcripts that are involve in gastrointestinal carcinogenesis and have been proposed as promising diagnostic or prognostic biomarkers and as potential therapeutic targets in these malignancies. This review describes important topics about piRNAs including their molecular characteristics, biosynthesis processes, gene expression silencing mechanisms, and the manner in which these transcripts have been studied in samples and cell lines of GI cancers. In addition, this article discusses the potential clinical usefulness of piRNAs as biomarkers and therapeutic targets in GI cancers. Gastrointestinal (GI) cancers produce ~3.4 million related deaths worldwide, comprising 35% of all cancer-related deaths. The high mortality among GI cancers is due to late diagnosis, the presence of metastasis and drug resistance development. Additionally, current clinical markers do not adequately guide patient management, thereby new and more reliable biomarkers and therapeutic targets are still needed for these diseases. RNA-seq technology has allowed the discovery of new types of RNA transcripts including PIWI-interacting RNAs (piRNAs), which have particular characteristics that enable these molecules to act via diverse molecular mechanisms for regulating gene expression. Cumulative evidence has described the potential role of piRNAs in the development of several tumor types as a likely explanation for certain genomic abnormalities and signaling pathways' deregulations observed in cancer. In addition, these piRNAs might be also proposed as promising diagnostic or prognostic biomarkers or as potential therapeutic targets in malignancies. This review describes important topics about piRNAs including their molecular characteristics, biosynthesis processes, gene expression silencing mechanisms, and the manner in which these transcripts have been studied in samples and cell lines of GI cancers to elucidate their implications in these diseases. Moreover, this article discusses the potential clinical usefulness of piRNAs as biomarkers and therapeutic targets in GI cancers.
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    The ERK/MAPK pathway is overexpressed and activated in gallbladder cancer
    (2017) Buchegger, Kurt; Silva, Ramón; López, Jaime; Lli, Carmen; Araya, Juan Carlos; Leal, Pamela; Brebi, Priscilla; Riquelme, Ismael; Roa Strauch, Juan Carlos Enrique
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    The Gene Expression Status of the PI3K/AKT/mTOR Pathway in Gastric Cancer Tissues and Cell Lines
    (2016) Riquelme, Ismael; Tapia, Óscar; Espinoza, Jaime A.; Leal, Pamela; Buchegger, Kurt; Sandoval, Alejandra; Bizama, Carolina; Araya, Juan Carlos; Peek, Richard M.; Roa Strauch, Juan Carlos Enrique