RESUMO
Human NK cells can be separated into two functionally distinct subpopulations based on the ability to rapidly respond to IL-2 by adherence to solid surfaces. To determine functions of the NK cell subsets in solid tumor tissues, adherent (A) and nonadherent (NA) NK cells were evaluated for their ability to infiltrate multicellular tumor spheroids in vitro, to kill carcinoma (CA) cell targets in these spheroids, and to mediate antitumor activity in vivo. A-NK cells were less cytolytic than NA-NK cells against CA targets in single cell suspensions or in monolayers. However, A-NK cells showed a significantly better ability than NA-NK cells to infiltrate tumor tissues and kill tumor cells in spheroids of human squamous cell CA of the head and neck or breast CA. Perilesional delivery of human A-NK cells and IL-2 resulted in regression of established human squamous cell carcinoma of the head and neck tumors growing subcutaneously in immunosuppressed nude mice. Similarly, in a xenograft model of human gastric CA metastatic to liver of nude mice, a single intrasplenic injection of A-NK cells in combination with i.p. infusions of IL-2 significantly reduced the number of established hepatic metastases (p < 0.007) and prolonged survival of the mice (p < 0.003). In contrast, NA-NK cells were ineffective in either of the in vivo xenograft tumor models. These findings demonstrate that A-NK cells represent a biologically unique and important subset of NK cells that, in contrast to the rest of NK cells, function as effector cells in solid tumor tissues and, consequently, have a great antitumor therapeutic potential.
Assuntos
Adenocarcinoma/terapia , Neoplasias da Mama/terapia , Carcinoma de Células Escamosas/terapia , Neoplasias de Cabeça e Pescoço/terapia , Imunoterapia Adotiva , Interleucina-2/farmacologia , Células Matadoras Ativadas por Linfocina/imunologia , Neoplasias Hepáticas/secundário , Subpopulações de Linfócitos/imunologia , Adenocarcinoma/imunologia , Animais , Neoplasias da Mama/imunologia , Carcinoma de Células Escamosas/imunologia , Adesão Celular , Movimento Celular , Testes Imunológicos de Citotoxicidade , Feminino , Neoplasias de Cabeça e Pescoço/imunologia , Humanos , Interleucina-2/uso terapêutico , Células Matadoras Ativadas por Linfocina/efeitos dos fármacos , Células Matadoras Ativadas por Linfocina/transplante , Neoplasias Hepáticas/terapia , Subpopulações de Linfócitos/efeitos dos fármacos , Subpopulações de Linfócitos/transplante , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Transplante de Neoplasias , Organoides , Neoplasias Gástricas/patologia , Transplante Heterólogo , Células Tumorais CultivadasRESUMO
Natural killer (NK) cells selected by IL-2-induced rapid adherence to plastic and called A-NK cells represent a phenotypically and functionally distinct subset of mature peripheral blood NK cells. To further characterize this subset of NK cells functionally, their potential to express mRNA for the IL-2R and various cytokines after IL-2 activation was examined. Highly purified normal human peripheral blood resting NK (R-NK) cells were obtained by negative immunoselection using OKT3 mAb and magnetic beads coated with goat anti-mouse Ig. By two-color flow cytometry, > 90% of these R-NK cells were either CD3-CD56+CD16+ or - or CD3-CD56-CD16+. R-NK cells were activated in the presence of 6000 IU/ml (22 nM) of IL-2 for different periods of time. After 1, 3, 5, or 24 h, plastic-adherent (A) and nonadherent (NA) NK cells were separated and compared for the expression of the IL-2R or cytokine mRNA by in situ hybridization, using 35[S]-cDNA probes. Only low proportions of R-NK cells expressed genes for IL-2Rp55 (16%) or cytokines IL-2 (20%), IFN-gamma (18%), TNF-alpha (16%), and TGF-beta (7%). Thus, the genes for the IL-2Rp55 and these cytokines were not constitutively expressed by most human R-NK cells, and there was no indication that the NK cells used in these experiments were activated in vivo or during the purification procedure. However, larger proportions of R-NK cells showed expression of mRNA for IL-1-beta (35%) and IL-6 (40%), which indicates that genes for these cytokines may be constitutively expressed in a substantial proportion of normal human circulating NK cells. When R-NK cells were incubated in the presence of 22 nM of IL-2 for 1 to 24 h and separated into A-NK cells and NA-NK cells, a large proportion of A-NK cells became positive for IL-2R and cytokine gene expression. In contrast, the proportion of mRNA-positive NA-NK cells was similar or lower than that observed for R-NK cells, with the exception of an increase in TGF-beta.(ABSTRACT TRUNCATED AT 400 WORDS)