k562 chronic myelogenous leukemia cell line  (ATCC)

Journal: bioRxiv

Article Title: Feeder cell – the key component in producing scalable and fit NK cells for therapeutic use

doi: 10.64898/2026.04.21.718880

Figure Lengend Snippet: (A) Schematic representation of chimeric transgene constructs introduced into K562 feeder cells via lentiviral transduction. (B) Representative flow cytometry histograms showing surface expression of transgenes following lentiviral transduction of the K562 cell line. (C) Quantification of TGF-β1 from supernatants of irradiated feeder cells (illustrated) cultured alone or co-cultured with NK cells over a 72-hour period. Co-cultures were initiated at a density of 0.5 × 10 6 cells/mL, with NK cells added at an effector-to-target (E:T) ratio of 1:5. Supernatants were collected at the endpoint. Data are presented as mean ± standard deviation (SD) from n = 3 individual donors. Statistical analysis comparisons of feeder cells were made against K562 cells and another comparison between feeder cells alone vs co-cultures as indicated by lines between the pairs using two-sample paired t-test and two-sample unequal-variance t-test. p < 0.05 (*), p < 0.01 (**), p < 0.001 (***).

Article Snippet: The K562 chronic myelogenous leukemia cell line was purchased from ATCC (K-562; CCL-243) and used to generate the modified feeder cells.

Techniques: Construct, Transduction, Flow Cytometry, Expressing, Irradiation, Cell Culture, Standard Deviation, Comparison

Journal: bioRxiv

Article Title: Feeder cell – the key component in producing scalable and fit NK cells for therapeutic use

doi: 10.64898/2026.04.21.718880

Figure Lengend Snippet: NK cell cytotoxicity against K562 target cells was assessed in a 24-hour co-culture assay at varying effector-to-target (E:T) ratios. NK cells were collected for the assay at multiple timepoints: starting immediately after thawing (A), and at weeks 1 (B) and 4 (C), as well as during each sample’s the week precedin the last week of survival lon -term culture (D). (E) Responsiveness to IL-2 stimulation was evaluated in thawed NK cells using a 24-hour co-culture assay with K562 cells immediately after thawing. 500 IU/ml IL-2 was either added (+) or omitted (–) from the co-culture to assess its effect on cytotoxic activity. (F) Cytotoxicity against NALM-6 cells and (G) SH-Sy5y cells were measured one week after thawing using 24-hour co-culture assays. Each dot represents an individual donor; bars indicate mean values. Data are presented as mean ± SD from (A) n = 3, (B) n = 6, (C) n = 3, (D) n = 3, (E) n = 3, (F) n = 6 and (G) n = 6 individual donors. Data (E) points represent individual donors: donor A (circles), B (triangles) and C (squares). Statistical analysis comparisons were made against the Day 1, non-expanded NK cell condition and in (E) by comparing IL-2 added and omitted condition, using two-tailed paired t-test. p < 0.05 (*), p < 0.01 (**), p < 0.001 (***).

Article Snippet: The K562 chronic myelogenous leukemia cell line was purchased from ATCC (K-562; CCL-243) and used to generate the modified feeder cells.

Techniques: Co-culture Assay, Co-Culture Assay, Activity Assay, Two Tailed Test

Journal: bioRxiv

Article Title: Feeder cell – the key component in producing scalable and fit NK cells for therapeutic use

doi: 10.64898/2026.04.21.718880

Figure Lengend Snippet: (A) NK cells were co-cultured for 4 hours with (+) or without (–) K562 target cells and analyzed by flow cytometry after live/CD56+ gating. Surface expression of the activation marker CD69, degranulation marker CD107a, and apoptosis-inducing ligands FasL and TRAIL were measured on NK cells. Marker expression was quantified using median fluorescence intensity (MFI). (B) Secretion of inflammatory cytokines (IFN-γ and N -α) and cytotoxic granule components (granzyme B and perforin) were measured from co-culture supernatants using a multiplex bead-based assay. Data are presented as mean ± SD from (A) and (B) n = 3 individual donors. Data (A) and (B) points represent individual donors: donor A (circles), B (triangles) and C (squares). Statistical analysis comparisons were made against the Day 1, non-expanded NK cell condition unless otherwise indicated using two-tailed paired t-test. p < 0.05 (*), p < 0.01 (**), p < 0.001 (***).

Article Snippet: The K562 chronic myelogenous leukemia cell line was purchased from ATCC (K-562; CCL-243) and used to generate the modified feeder cells.

Techniques: Cell Culture, Flow Cytometry, Expressing, Activation Assay, Marker, Fluorescence, Co-Culture Assay, Multiplex Assay, Bead-based Assay, Two Tailed Test

Journal: Biomedicines

Article Title: Antibody-Mediated In Vitro Activation and Expansion of Blood Donor-Derived Natural Killer Cells with Transient Anti-Tumor Efficacy

doi: 10.3390/biomedicines13122934

Figure Lengend Snippet: SNK cells exhibited enhanced cytotoxicity and effector molecule secretion in vitro (n = 3 donors). ( A ) Representative images depicting the cytotoxic effects of SNK and PBNK cells against HK-1, DU145, and K562 tumor cells after 6 h of co-culture. ( B ) Cytotoxicity was quantified at various E:T ratios using luciferase-based assays (for the other two donors of SNK against tumors, see also ). ( C ) Mean cytotoxicity against all three tumor cells, determined by luminescence. ( D , E ) Concentrations of IFN-γ ( D ) and Gzm B ( E ) in the co-culture supernatants were quantified by ELISA. Data are presented as mean ± SEM. Statistical analysis was performed using Student’s t test. Significant differences are indicated as * p < 0.05, ** p < 0.01, and *** p < 0.001; ns = not significant.

Article Snippet: Human nasopharyngeal carcinoma cell line HK-1 (YC-C095, Ubigene, Cambridge, MA, USA), human prostate cancer cell line DU145 (HTB-81, ATCC, Manassas, VA, USA), and chronic myelogenous leukemia cell line K562 (CCL-243, ATCC, Manassas, VA, USA) were cultured in complete RPMI-1640 medium supplemented with 10% fetal bovine serum (FBS; Gibco, Grand Island, NY, USA) at 37 °C in a humidified atmosphere containing 5% CO 2 .

Techniques: In Vitro, Co-Culture Assay, Luciferase, Enzyme-linked Immunosorbent Assay

Journal: Biomedicines

Article Title: Antibody-Mediated In Vitro Activation and Expansion of Blood Donor-Derived Natural Killer Cells with Transient Anti-Tumor Efficacy

doi: 10.3390/biomedicines13122934

Figure Lengend Snippet: SNK cells exhibited enhanced cytotoxicity against tumor cells in vivo. ( A ) NSG mice were intravenously injected with 1 × 10 6 K562-Luc cells through the tail vein. On day 3, mice were intravenously administered SNK cells at doses of 2 × 10 7 , 4 × 10 7 , or 8 × 10 7 cells. Tumor burden was monitored on days 3, 10, and 17 using bioluminescence imaging. ( B ) Representative bioluminescence images showing tumor progression over time. ( C ) Kaplan–Meier survival curves were generated, and statistical significance was determined using the log-rank test (* p < 0.05; ns = not significant), with a large effect size (Hazard Ratio = 2.59). ( D ) The body weights of mice were measured post-K562 cell inoculation at the indicated time points. The percentage of SNK cells (CD56 + CD3 − ) was determined by flow cytometry in the peripheral blood (PB, ( E , F )) and spleen ( G ) of mice post-SNK cell infusion.

Article Snippet: Human nasopharyngeal carcinoma cell line HK-1 (YC-C095, Ubigene, Cambridge, MA, USA), human prostate cancer cell line DU145 (HTB-81, ATCC, Manassas, VA, USA), and chronic myelogenous leukemia cell line K562 (CCL-243, ATCC, Manassas, VA, USA) were cultured in complete RPMI-1640 medium supplemented with 10% fetal bovine serum (FBS; Gibco, Grand Island, NY, USA) at 37 °C in a humidified atmosphere containing 5% CO 2 .

Techniques: In Vivo, Injection, Imaging, Generated, Flow Cytometry