Variable characteristics overlooked in human K-562 leukemia cell lines with a common signature.

K-562 is a well-known in vitro cellular model that represents human leukemia cell lines. Although the K-562 cells have been extensively characterized, there are inconsistencies in the data across publications, showing the presence of multiple K-562 cell lines. This suggests that analyzing a single K-562 cell line is insufficient to provide reliable reference data. In this study, we compared three K-562 cell lines with different IDs (RCB0027, RCB1635, and RCB1897) to investigate the fundamental characteristics of K-562 cells. Amplifications of the BCR-ABL1 fusion gene and at 13q31 were detected in all three cell lines, whereas each genome exhibited distinctive features of sequence variants and loss of heterozygosity. This implies that each K-562 cell line can be characterized by common and unique features through a comparison of multiple K-562 cell lines. Variations in transcriptome profiles and hemoglobin synthesis were also observed among the three cell lines, indicating that they should be considered sublines that have diverged from the common ancestral K-562 despite no changes from the original cell name. This leads to unintentional differences in genotypes and/or phenotypes among cell lines that share the same name. These data show that characterizing a single K-562 cell line does not necessarily provide data that are applicable to other K-562 cells. In this context, it is essential to modify cell names in accordance with changes in characteristics during cell culture. Furthermore, our data could serve as a reference for evaluating other K-562 sublines, facilitating the discovery of new K-562 sublines with distinct characteristics. This approach results in the accumulation of K-562 sublines with diverged characteristics and expands the options available, which may help in selecting the most suitable K-562 subline for each experiment.

Obtención de la sublínea celular CLA-HT. Estudio de su sensibilidad para el aislamiento y multiplicación de los virus del dengue / Obtainment of CLA-HT cell subline and study of its susceptibility for the isolation and multiplication of the dengue virus

Introducción: en el diagnóstico de dengue es importante la determinación del serotipo viral. A pesar de existir otros métodos, el aislamiento viral en cultivos de células y la identificación por la técnica de inmunofluorescencia siguen siendo muy utilizados. Por lo tanto, la búsqueda de sistemas celulares más sensibles ha sido un tema reiterado durante muchos años para el virus dengue y otros agentes. Objetivo: obtener una sublínea celular a partir del clon CLA-1 (Aedes pseudoscutellaris) que crece a 28 ºC, capaz de multiplicarse a 33ºC (CLA-HT) y evaluar su utilidad para el aislamiento y la identificación de los virus del dengue. Métodos: a partir del clono CLA-1 de la línea celular AP-61(Aedes pseudoscutellaris) se obtuvo por selección una cepa o sublínea celular CLA-HT capaz de crecer a 33 °C. Se estudió su sensibilidad para la multiplicación de los 4 serotipos del virus del dengue y su eficiencia para el aislamiento directo de sueros de pacientes en fase aguda de la enfermedad, ambos comparativamente con la línea C6/36HT (A. albopictus). Resultados: la sublínea CLA-HT permitió el crecimiento de los 4 serotipos del virus dengue aunque para algunos requirió más tiempo que la C6/36 HT. Para el aislamiento a partir de muestras de sueros colectadas de individuos en fase aguda, la sublínea CLA-HT detectó el virus en el 40 por ciento de las muestras, mientras que C6/36 detectó el virus en el 50 por ciento. Discusión: CLA-HT es capaz de detectar todos los serotipos del virus dengue a partir de las 96 horas pos inoculación, por lo que es útil para la investigación como sistema alternativo y su eficiencia de aislamiento directo es buena para aplicar en grandes brotes. Además, la principal ventaja es que es posible utilizarla para proporcionar una respuesta rápida a situaciones emergentes en laboratorios de escasos recursos, ya que no precisa de condiciones de incubación con CO2. Conclusiones: se obtuvo una sublínea CLA-HT a partir de la línea CLA-1 capaz de crecer a 33ºC, la cual detecta los 4 serotipos del virus dengue. Su eficiencia de aislamiento es ligeramente menor que la sublínea C6/36 HT, pero se puede utilizar como sistema alternativo para el aislamiento de los virus dengue sobre todo en laboratorios con bajos recursos que no cuenten con condiciones óptimas de incubación(AU)

Introduction: the identification of viral serotypes is an important issue for dengue diagnosis. Despite the existence of other identification methods, the viral isolation in cell cultures and determination by immunofluorescent technique remain as the most used. Therefore the search for more sensitive cellular systems has been a repeated topic during many years for dengue virus and other agents. Objective: to obtain a cell subline from CLA-1 clone (Aedes pseudoscutellaris), that grows at 28 °C, capable of multiplying at 33 °C (CLA-HT)and to evaluate its usefulness for Dengue virus isolation and identification. Methods: by using a CLA-1 clone of the AP-61(Aedes pseudoscutellaris) cell line, it was possible to obtain a strain or cell subline CLA-HT capable of growing at 33 oC (CLA-HT) through a temperature selection method. Its sensitivity for the multiplication of the 4 dengue virus serotypes and its efficiency for direct virus isolation from acutely ill patients' sera were studied in comparison to C6/36 HT cell line (A. albopictus). Results: four dengue virus serotypes grew in CLA-HT cell subline but some serotypes were detected later in CLA-HT than in C6/36 HT. For dengue isolation from serum samples taken in acutely ill patients, the CLA-HT subline detected 40 percent positive samples whereas C6/36 HT did 50 percent. Discussion: CLA-HT is able to detect all dengue virus serotypes from 96 hours on post inoculation. It makes the new cell line useful for research as an alternative system and the direct isolation efficiency is good to be applied in large outbreaks. The most important advantage of CLA-HT is the possibility of giving rapid answer in emergency situations in low resource laboratories since it does not require special incubation conditions with CO2. Conclusions: a CLA-HT subline was obtained from CLA-1 line and it grows at 33 oC and capable of detecting 4 dengue virus serotypes. Its isolation efficiency is slightly lower than that of C6/36 HT subline, but it may be used as an alternative system for dengue virus isolation, mainly in resource-poor laboratories that do not have the optimal conditions for incubation(AU)

Establishment of L1210 cell line resistant to cis-diamminedichloro- platinum and a preliminary observation on its biology / 中国药理学通报

AIM To establish the expermental model in vitro for the study of mechanism of antitumor drug resistance and the screening of antitumor drug. METHODS By continuously exposing cells to gradually increasing concentration of drug and agar cell colony forming technique, using dye exclusive method for determing cytotoxic effect, a murine leukemia L1210 cell subline were established,which exhibited 40 fold resistance to Cis diamminedichloro platinum(DDP). RESULTS The doubling times, plate efficiency, cell cycle, DNA index and cell morphology of DDP resistant L1210 subline were similarto those of its parant cell line. When the cell subline was stored with DDP at -196℃ for 6 months and then was recovered, its characterization of antitumor drug resistance was still maintained to a period of 5 months without DDP. DDP resistant L1210 subline was characterized with cross resistance to Carboplatin, Mitomycin, Thio Tepa, Methotrexate, Vincristin and Mustine Hydrochloride, but with no cross resistance to Harringtonine and Adriamycin. It was seemed more sensitive to Cytarabine and Fluorouracil. CONCLUSION DDP resistant L1210 subline is a good experimental model in vitro for the study of mechanism of antitumor drug resistance and the screening of antitumor drug.