Browsing by Author "Rojas, N"

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Biological characteristics of a sub-population of cancer stem cells from two triple-negative breast tumour cell lines
(Heliyon, 2021) Enciso-Benavides, J; Alfaro, L; Castañeda-Altamirano, C; Rojas, N; Gonzalez-Cabeza, J; Enciso, N; Riesco, F; Castillo, M; Enciso, J
Triple-negative breast tumours (TNBTs) make up 15-20% of all breast tumours. There is no treatment for them, and the role that cancer stem cells (CSCs) have in carcinogenesis is still unclear, so finding markers and therapeutic targets in CSC exosomes requires these cells to exist as a homogeneous cell population. The objective of this work was to determine differences in ultrastructural morphology, proliferative capacity, and mouse-xenotransplantation characteristics of the MDA-MB-231 and MDA-MB-436 TNBT cell lines with the CD44 high /CD24 low phenotype in order to study their exosomes. The results show that the CD44 high /CD24 low MBA-MB-231 cells had a population doubling time of 41.56 h, compared to 44.79 h in the MDA-MB-436 cell line. After magnetic immunoseparation, 18.75% and 14.56% of the stem cell population of the MDA-MB-231 and MDA-MB-436 cell lines, respectively, were of the CD44 high /CD24 low phenotype, which were expanded to reach purities of 80.4% and 87.6%. The same expanded lineage in both cell lines was shown to possess the pluripotency markers Nanog and Oct4. Under a scanning electron microscope, the CD44 high /CD24 low lineage of the MBA-MD-231 cell line formed groups of more interconnected cells than this lineage of the MBA-MD-436 line. A total of 16% of the mice inoculated with the CD44 high /CD24 low lineage of either cell line presented tumours of the breast, lung, and submandibular ganglia, in whose tissues variable numbers of inoculated cells were found 30 days post-inoculation. By magnetic immunoselection, it was possible to isolate in similar quantities and characterize, expand, and xenotransplant the CD44 high /CD24 low lineage of the MDA-MB-231 and MDA-MB-436 cell lines. The former cell line has greater proliferative capacity, the two lines differ under scanning electron microscopy in how they intercommunicate, and both cell lines induce new tumours in mice and persist at least 30 days post-inoculation in the transplanted animal so their exosomes would also be different.
Clinical networking results in continuous improvement of the outcome of patients with acute promyelocytic leukemia
(Elsevier B.V., 2024) Koury, LCDA; Kim, HT; Undurraga, MS; Navarro-Cabrera, JR; Salinas, V; Muxi, P; Melo, RAM; Glória, AB; Pagnano, K; Nunes, EC; Bittencourt, RI; Rojas, N; Quintana, S; Ayala-Lugo, A; Oliver, AC; Figueiredo-Pontes, L; Traina, F; Moreira, F; Fagundes, EM; Duarte, BKL; Mora-Alferez, AP; Ortiz, P; Untama, J; Tallman, M; Ribeiro, R; Ganser, A; Dillon, R; Valk, PJM; Sanz, M; Löwenberg, B; Berliner, N; Rego, EM
The introduction of all-trans retinoic acid combined with anthracyclines has significantly improved the outcomes for patients diagnosed with acute promyelocytic leukemia (APL), and this strategy remains the standard of care in countries in which arsenic trioxide is not affordable. However, data from national registries and real-world databases indicate that low- and middle-income countries (LMIC) still face disappointing results, mainly because of high induction mortality and suboptimal management of complications. The American Society of Hematology established the International Consortium on Acute Leukemias (ICAL) to address this challenge through international clinical networking. Here, we present the findings from the International Consortium on Acute Promyelocytic Leukemia study involving 806 patients with APL recruited from 2005 to 2020 in Brazil, Chile, Paraguay, Peru, and Uruguay. The induction mortality rate has notably decreased to 14.6% compared with the pre-ICAL rate of 32%. Multivariable logistic regression analysis revealed as factors associated with induction death: age of ≥40 years, Eastern Cooperative Oncology Group performance status score of 3, high-risk status based on the Programa Español de Tratamiento en Hematologia/Gruppo Italiano Malattie EMatologiche dell'Adulto classification, albumin level of ≤3.5 g/dL, bcr3 PML/RARA isoform, the interval between presenting symptoms to diagnosis exceeding 48 hours, and the occurrence of central nervous system and pulmonary bleeding. With a median follow-up of 53 months, the estimated 4-year overall survival rate is 81%, the 4-year disease-free survival rate is 80%, and the 4-year cumulative incidence of relapse rate is 15%. These results parallel those observed in studies conducted in high-income countries, highlighting the long-term effectiveness of developing clinical networks to improve clinical care and infrastructure in LMIC.
Fortalecimiento de las políticas de salud pública contra el cáncer infantil: logros de Perú en el marco de la Iniciativa Mundial de la OMS contra el Cáncer Infantil
(Pan American Health Organization, 2023) Maradiegue, E; Pascual, C; Vasquez, L; Maza, I; Ugaz, C; Montoya, J; Zapata, A; García, H; Chavez, S; Ordoñez, K; Rossi, J; Diaz, R; Morales, R; Trigoso, V; Ames, R; Celis, E; Barzola, I; Torres, L; Cosme, M; Tarrillo, F; Rojas, N; Santillan, C; Quispe, Y; Palacios, V; Godoy, V; Tello, M; Tarco, D; Wachtel, A; Malaver, E; Diaz, E; Goyburu, M; Perez, V; Talavera, I; Baca, ME; Maza M; Saldaña, L; Holguin, A; Jarquin, M; Loggetto, P; Metzger, M; Friedrich, P; Lam, C; Rodriguez-Galindo, C
Objective. To report the progress in Peru, since June 2019, in the implementation of the World Health Organization Global Initiative for Childhood Cancer using the CureAll framework, which can be replicated in low- and middle-income countries. Methods. A mixed method was used of participatory and documentary evaluation. The participatory evaluation included stakeholders from various government institutions, nonprofit organizations, and international partners. The documentary aspect consisted of a review of data on the regulatory environment, national projects, and interventions implemented. The Ministry of Health engaged more than 150 participants to form working committees, which have developed policy and regulatory documents to strengthen care services. Results. Achievements include a decrease in the national treatment abandonment rate from 18.6% to 8.5%, the approval of the Childhood Cancer Law, improvements in the management of patients with febrile neutropenia, and a reduction in rates of events of clinical deterioration and mortality of hospitalized patients. The Cure All implementation framework allows local teams to implement specific strategies and monitor early outcomes in pediatric oncology. Conclusions. The results obtained reflect the teamwork, the leadership of the authorities, the technical support of professionals, and the support of involved organizations. Further actions will be needed to guarantee sustainability, and monitoring tools are needed to assure success in the planned activities.