Current Organizations / Institutes

The organizations/institutes from the scholar's latest article


Pamela Leal has a total of 98 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Dysregulated lncRNAs in Cisplatin-Induced Nephrotoxicity and Their Association with Apoptosis and Autophagy: An Exploratory In Vitro Study

    by Yuliannis Lugones, Pía Loren, Carola E. Matus, Nelia M. Rodriguez, Pamela Leal-Rojas, Rody San Martín, Kathleen Saavedra, Nicolás Saavedra, Patricia Moriel, Luis A. Salazar

    Cisplatin is a widely used chemotherapeutic agent, but its clinical application is limited by nephrotoxicity. Conventional renal markers lack sensitivity for early cisplatin nephrotoxicity while long non-coding RNAs (lncRNAs) display cisplatin-responsive changes with exploratory value. The present study aimed to explore the differential expression of eight lncRNAs on in vitro model of cisplatin-induced nephrotoxicity. Human kidney cell lines HEK-293 and HK-2 were exposed to increasing concentrations of cisplatin for 24 h. Cell viability was determined by colorimetric assays to ascertain the concentrations resulting in 25% (IC25), 50% (IC50), and 75% (IC75) cell death (inhibitory concentration). Apoptotic and autophagy-related proteins were analyzed by Western blot, and reverse transcription–polymerase chain reaction was employed to evaluate the expression of the lncRNAs. Cisplatin-induced cell death with IC25, IC50, and IC75 values of 8.8, 15.43 and 27 μM for HEK-293 cells, and 8.1, 13.57, and 22.8 μM for HK-2 cells. Protein analysis showed an increase in cleaved caspase-9, reduction of caspase-3 and increased LC3-II/LC3-I ratio, with no changes in caspase 7 and Beclin-1. The lncRNAs UCA1, XLOC_032768, HOTAIR, LINC-ROR, and PRNCR1 were downregulated, whereas OIP5-AS1 was upregulated; in contrast, GAS5 and PVT1 remained unchanged. In conclusion, this exploratory in vitro study identifies cisplatin-responsive dysregulation of lncRNAs in human renal cells and delineates their associations with apoptosis and autophagy.


  • Open Access

    Una Sola Salud. Un Enfoque Multisectorial y Transdisciplinario

    by Carlos Manterola, Josue Rivadeneira, Pamela Leal, Claudio Rojas-Pincheira, Adison Altamirano

    Una sola salud (USS), es un enfoque integral y unificador diseñado para equilibrar y optimizar la salud tanto de seres humanos, animales y ecosistemas, aprovechando la interrelación entre estos ámbitos para establecer nuevas metodologías de vigilancia y control de enfermedades. Es así como, la forma en que se utiliza el suelo puede influir en el número de casos de malaria; las condiciones meteorológicas y controles artificiales del agua pueden afectar enfermedades como el dengue; el comercio de animales salvajes vivos puede aumentar la probabilidad de que ciertas enfermedades infecciosas se transmitan de animales a humanos (zoonosis), entre otros ejemplos. Es decir, un esfuerzo integrador de múltiples disciplinas que trabajan de manera colaborativa a nivel local, nacional y global en todos los aspectos del cuidado de la salud de los seres humanos, los animales y el medio ambiente. El objetivo de este manuscrito fue reportar y discutir el concepto USS, como nuevo enfoque sanitario inter y transdisciplinario. Debemos adoptar la filosofía de USS desde el nivel global hasta el más local para reducir entre otras, los riesgos de pandemias que pueden ocurrir con mayor frecuencia considerando el crecimiento exponencial de la población mundial y la urbanización.


  • Open Access

    Construction of a Human Immune Library from Gallbladder Cancer Patients for the Single-Chain Fragment Variable (scFv) Antibody Selection against Claudin 18.2 via Phage Display

    by Brian Effer, Daniel Ulloa, Camila Dappolonnio, Francisca Muñoz, Isabel Iturrieta-González, Loraine Cotes, Claudio Rojas, Pamela Leal

    Gallbladder cancer (GBC) is a very aggressive malignant neoplasm of the biliary tract with a poor prognosis. There are no specific therapies for the treatment of GBC or early diagnosis tools; for this reason, the development of strategies and technologies that facilitate or allow an early diagnosis of GBC continues to be decisive. Phage display is a robust technique used for the production of monoclonal antibodies (mAbs) involving (1) the generation of gene libraries, (2) the screening and selection of isoforms related to an immobilized antigen, and (3) the in vitro maturation of the affinity of the antibody for the antigen. This research aimed to construct a human immune library from PBMCs of GBC patients and the isolation of scFv-phage clones with specificity against the larger extracellular loop belonging to claudin 18.2, which is an important biomarker overexpressed in GBC as well as gastric cancer. The immune-library-denominated GALLBLA1 was constructed from seven GBC patients and has a diversity of 6.12 × 1010 pfu mL−1. After three rounds of panning, we were able to identify clones with specificity against claudin 18.2. GALLBLA1 can contribute to the selection, isolation, and recombinant production of new human mAbs candidates for the treatment of gastrointestinal cancers.


  • Open Access

    Therapeutic Targets of Monoclonal Antibodies Used in the Treatment of Cancer: Current and Emerging

    by Brian Effer, Isabela Perez, Daniel Ulloa, Carolyn Mayer, Francisca Muñoz, Diego Bustos, Claudio Rojas, Carlos Manterola, Luis Vergara-Gómez, Camila Dappolonnio, et al.

    Cancer is one of the leading global causes of death and disease, and treatment options are constantly evolving. In this sense, the use of monoclonal antibodies (mAbs) in immunotherapy has been considered a fundamental aspect of modern cancer therapy. In order to avoid collateral damage, it is indispensable to identify specific molecular targets or biomarkers of therapy and/or diagnosis (theragnostic) when designing an appropriate immunotherapeutic regimen for any type of cancer. Furthermore, it is important to understand the currently employed mAbs in immunotherapy and their mechanisms of action in combating cancer. To achieve this, a comprehensive understanding of the biology of cancer cell antigens, domains, and functions is necessary, including both those presently utilized and those emerging as potential targets for the design of new mAbs in cancer treatment. This review aims to provide a description of the therapeutic targets utilized in cancer immunotherapy over the past 5 years, as well as emerging targets that hold promise as potential therapeutic options in the application of mAbs for immunotherapy. Additionally, the review explores the mechanisms of actin of the currently employed mAbs in immunotherapy.


  • Open Access

    A Novel Gemcitabine-Resistant Gallbladder Cancer Model Provides Insights into Molecular Changes Occurring during Acquired Resistance

    by Luis Vergara-Gómez, Carolina Bizama, Jun Zhong, Kurt Buchegger, Felipe Suárez, Lorena Rosa, Carmen Ili, Helga Weber, Javiera Obreque, Karena Espinoza, et al.

    Treatment options for advanced gallbladder cancer (GBC) are scarce and usually rely on cytotoxic chemotherapy, but the effectiveness of any regimen is limited and recurrence rates are high. Here, we investigated the molecular mechanisms of acquired resistance in GBC through the development and characterization of two gemcitabine-resistant GBC cell sublines (NOZ GemR and TGBC1 GemR). Morphological changes, cross-resistance, and migratory/invasive capabilities were evaluated. Then, microarray-based transcriptome profiling and quantitative SILAC-based phosphotyrosine proteomic analyses were performed to identify biological processes and signaling pathways dysregulated in gemcitabine-resistant GBC cells. The transcriptome profiling of parental and gemcitabine-resistant cells revealed the dysregulation of protein-coding genes that promote the enrichment of biological processes such as epithelial-to-mesenchymal transition and drug metabolism. On the other hand, the phosphoproteomics analysis of NOZ GemR identified aberrantly dysregulated signaling pathways in resistant cells as well as active kinases, such as ABL1, PDGFRA, and LYN, which could be novel therapeutic targets in GBC. Accordingly, NOZ GemR showed increased sensitivity toward the multikinase inhibitor dasatinib compared to parental cells. Our study describes transcriptome changes and altered signaling pathways occurring in gemcitabine-resistant GBC cells, which greatly expands our understanding of the underlying mechanisms of acquired drug resistance in GBC.


  • Open Access

    Controlled Release of Caffeic Acid and Pinocembrin by Use of nPSi-βCD Composites Improves Their Antiangiogenic Activity

    by Dina Guzmán-Oyarzo, Jacobo Hernández-Montelongo, Carlos Rosas, Pamela Leal, Helga Weber, Marysol Alvear, Luis A. Salazar

    Although polyphenols have great pharmacological potential, the main disadvantage is that they have low bioavailability at the desired site. Thus, the use of biocompatible systems for drug delivery is a strategy that is currently gaining great interest. The objective of this study is to evaluate the effect of microencapsulation of caffeic acid and pinocembrin on the antioxidant and antiangiogenic activity of both polyphenols, by the use of nPSi-βCD composite microparticles. For this HUVEC, cells were exposed to H2O2 and to treatments with polyphenols in solution and loaded in the composite microparticle. The polyphenols were incorporated into a microparticle using nanoporous silicon, chitosan and a β-cyclodextrin polymer as the biomaterial. The evaluation of the antiangiogenic effect of the treatments with polyphenols in solution and microencapsulated was carried out through functional tests, and the changes in the expression of target genes associated with the antioxidant pathway and angiogenesis was performed through qPCR. The results obtained show that the caffeic acid and pinocembrin have an antioxidant and antiangiogenic activity, both in solution as microencapsulated. In the caffeic acid, a greater biological effect was observed when it was incorporated into the nPSi-βCD composite microparticle. Our results suggest that the nPSi-βCD composite microparticle could be used as an alternative oral drug administration system.


  • Open Access

    Exosomes and Cystic Echinococcosis. Systematic Review

    by Carlos Manterola, Pamela Leal

    Exosomes are small and single-membrane secreted organelles, up to 200 nm in diameter that have the same topology as the cell, but are enriched in proteins, nucleic acids, lipids, and glycoconjugates. It can be found in any type of body fluids such as plasma, urine, saliva, sperm, bile, etc. On the other hand, cystic Echinococcosis (CE) has been studied from different points of view, among others, from genomics and proteomics, and the presence of CE exosomes in humans and other intermediate hosts has been reported in very few articles. The aim of this review was to report the evidence available regarding exosomes and CE. Systematic review. Data sources: Trip Database, SciELO, WoS, MEDLINE, EMBASE and SCOPUS. Eligibility criteria: Studies related to CEin any type of host and state of the parasite, without language restriction, published between 1966-2021. Variables: Year of publication, geographical origin, species isolated, location of exosomes. Forty-two studies were initially identified. After scrutinizing titles and abstracts, checking duplications and in-depth analysis of the studies selected, 12 articles including human, bovine, sheep, dog samples were also included. All were case reports or case series. The highest proportion of articles was published between 2019 and 2021 (58.3 %). Publications were predominantly from China (58.3 %). Evidence about exosomes and CE is scarce and reduced range of articles and cases.

  • Open Access

    CRISPR/Cas13-Based Platforms for a Potential Next-Generation Diagnosis of Colorectal Cancer through Exosomes Micro-RNA Detection: A Review

    by Benjamín Durán-Vinet, Karla Araya-Castro, Juan Calderón, Luis Vergara, Helga Weber, Javier Retamales, Paulina Araya-Castro, Pamela Leal-Rojas

    Colorectal cancer (CRC) is the third most prevalent cancer with the second highest mortality rate worldwide. CRC is a heterogenous disease with multiple risk factors associated, including obesity, smoking, and use of alcohol. Of total CRC cases, 60% are diagnosed in late stages, where survival can drop to about 10%. CRC screening programs are based primarily on colonoscopy, yet this approach is invasive and has low patient adherence. Therefore, there is a strong incentive for developing molecular-based methods that are minimally invasive and have higher patient adherence. Recent reports have highlighted the importance of extracellular vesicles (EVs), specifically exosomes, as intercellular communication vehicles with a broad cargo, including micro-RNAs (miRNAs). These have been syndicated as robust candidates for diagnosis, primarily for their known activities in cancer cells, including immunoevasion, tumor progression, and angiogenesis, whereas miRNAs are dysregulated by cancer cells and delivered by cancer-derived exosomes (CEx). Quantitative polymerase chain reaction (qPCR) has shown good results detecting specific cancer-derived exosome micro-RNAs (CEx-miRNAs) associated with CRC, but qPCR also has several challenges, including portability and sensitivity/specificity issues regarding experiment design and sample quality. CRISPR/Cas-based platforms have been presented as cost-effective, ultrasensitive, specific, and robust clinical detection tools in the presence of potential inhibitors and capable of delivering quantitative and qualitative real-time data for enhanced decision-making to healthcare teams. Thereby, CRISPR/Cas13-based technologies have become a potential strategy for early CRC diagnosis detecting CEx-miRNAs. Moreover, CRISPR/Cas13-based platforms’ ease of use, scalability, and portability also showcase them as a potential point-of-care (POC) technology for CRC early diagnosis. This study presents two potential CRISPR/Cas13-based methodologies with a proposed panel consisting of four CEx-miRNAs, including miR-126, miR-1290, miR-23a, and miR-940, to streamline novel applications which may deliver a potential early diagnosis and prognosis of CRC.


  • Open Access

    Hippo-YAP1 Is a Prognosis Marker and Potentially Targetable Pathway in Advanced Gallbladder Cancer

    by Patricia García, Lorena Rosa, Sergio Vargas, Helga Weber, Jaime A. Espinoza, Felipe Suárez, Isabel Romero-Calvo, Nicole Elgueta, Vanessa Rivera, Bruno Nervi, et al.

    Gallbladder cancer is an aggressive disease with late diagnosis and no efficacious treatment. The Hippo-Yes-associated protein 1 (YAP1) signaling pathway has emerged as a target for the development of new therapeutic interventions in cancers. However, the role of the Hippo-targeted therapy has not been addressed in advanced gallbladder cancer (GBC). This study aimed to evaluate the expression of the major Hippo pathway components mammalian Ste20-like protein kinase 1 (MST1), YAP1 and transcriptional coactivator with PDZ-binding motif (TAZ) and examined the effects of Verteporfin (VP), a small molecular inhibitor of YAP1-TEA domain transcription factor (TEAD) protein interaction, in metastatic GBC cell lines and patient-derived organoids (PDOs). Immunohistochemical analysis revealed that advanced GBC patients had high nuclear expression of YAP1. High nuclear expression of YAP1 was associated with poor survival in GBC patients with subserosal invasion (pT2). Additionally, advanced GBC cases showed reduced expression of MST1 compared to chronic cholecystitis. Both VP treatment and YAP1 siRNA inhibited the migration ability in GBC cell lines. Interestingly, gemcitabine resistant PDOs with high nuclear expression of YAP1 were sensitive to VP treatment. Taken together, our results suggest that key components of the Hippo-YAP1 signaling pathway are dysregulated in advanced gallbladder cancer and reveal that the inhibition YAP1 may be a candidate for targeted therapy.


  • Open Access

    The Anti-Proliferative and Anti-Invasive Effect of Leaf Extracts of Blueberry Plants Treated with Methyl Jasmonate on Human Gastric Cancer In Vitro Is Related to Their Antioxidant Properties

    by Alejandra Ribera-Fonseca, Danae Jiménez, Pamela Leal, Ismael Riquelme, Juan Carlos Roa, Miren Alberdi, Richard M. Peek, Marjorie Reyes-Díaz

    Gastric cancer is the third main cause of cancerous tumors in humans in Chile. It is well-accepted that a diet rich in antioxidant plants could help in fighting cancer. Blueberry is a fruit crop with a high content of antioxidants. Methyl jasmonate (MeJA) is a phytohormone involved in plant defenses under stress conditions. The exogenous application of MeJA can improve the antioxidant properties in plants. We studied in vitro and in vivo anticancer action on human gastric cancer (cell line AGS) and the antioxidant properties of extracts from blueberry plants untreated and treated with MeJA. The results demonstrated that leaf extracts displayed a higher inhibition of cancer cell viability as well as greater antioxidant properties compared to fruit extracts. Besides, MeJA applications to plants improved the antioxidant properties of leaf extracts (mainly anthocyanins), increasing their inhibition levels on cell viability and migration. It is noteworthy that leaf extract from MeJA-treated plants significantly decreased cancer cell migration and expression of gastric cancer-related proteins, mainly related to the mitogen-activating protein kinase (MAPK) pathway. Interestingly, in all cases the anticancer and antioxidant properties of leaf extracts were strongly related. Despite highlighted outcomes, in vivo results did not indicate significant differences in Helicobacter pylori colonization nor inflammation levels in Mongolian gerbils unfed and fed with blueberry leaf extract. Our findings demonstrated that MeJA increased antioxidant compounds, mainly anthocyanins, and decreased the viability and migration capacity of AGS cells. In addition, leaf extracts from MeJA-treated plants were also able to decrease the expression of gastric cancer-related proteins. Our outcomes also revealed that the anthocyanin-rich fraction of blueberry leaf extracts showed higher in vitro antiproliferative and anti-invasive effects than the crude leaf extracts. However, it is still uncertain whether the leaf extracts rich in anthocyanins of blueberry plants are capable of exerting a chemopreventive or chemoprotective effect against gastric cancer on an in vivo model.