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Activated natural killer cell tumor retention and cytokine production in colon tumor using a tissue-isolated model
U Ribeiro1, T L Whiteside, P H Basse
1University of Pittsburgh, The University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania, USA.
Background:
Adoptively transferred activated natural killer (A-NK) cells are capable of selectively infiltrating solid tumors, but only at low efficiency when administered systemically. It is unclear if human A-NK cells can be retained in tumor tissue and, if so, what is their action. We investigated intratumor A-NK cell retention and in situ cytokine production, using an xenogeneic ex vivo tissue-isolated tumor model, which permits direct intraarterial infusion.
Materials And Methods:
Human colon adenocarcinoma (HT-29) was implanted in the ovarian fat pad of nude rats. The tumors were perfused ex vivo 25 to 30 days postimplant with a known number of cells, and the effluent was collected over time. The number of human A-NK cells and cell surface antigen expression of cells infused and exiting the tumor were calculated, using cell counts and flow cytometry, respectively. Frozen sections were stained with Giemsa and also immunostained for the presence of interleukin-2, -4, and -10, tumor necrosis factor alpha (TNF-alpha), and interferon.
Results:
Six perfusions with 8 x 10(6) A-NK cells were performed. The mean number of infused A-NK cells that remained in the tumor at the completion of perfusion was 4.74 x 10(6) (59.2%). No differences were noted in cellular phenotype between the infused cells and the cells exiting the tumor: expression of the markers CD45 (97.5% vs 94. 5%), CD14 (0 vs 0), CD3 (3.83% vs 2.83%), and CD56 (86% vs 83%) was unchanged, P > 0.05. Microscopic examination of tumor sections showed tumor surrounded by A-NK cells, with some tumor nests infiltrated by A-NK cells. In situ immunopositivity for interleukin-2 (2/6), interleukin-4 (3/6), interleukin-10 (2/6), and TNF-alpha (2/6) specimens was observed. Immunostaining for interferon-gamma was negative. Conclusions. The retention of A-NK cells in the transplanted human colon tumor tissue was found to be efficient (59.2 %) in this model. Although perfusion time was limited, A-NK cells were able to infiltrate the tumor and initiate cytokine production.
Insights
Adoptively transferred activated natural killer (A-NK) cells show efficient retention (59.2%) within human colon tumors in an ex vivo model. These A-NK cells infiltrate tumors and initiate cytokine production, suggesting potential for cancer therapy.
Area of Science:
- Immunology
- Oncology
- Cell Therapy
Background:
- Adoptively transferred activated natural killer (A-NK) cells demonstrate potential for solid tumor infiltration but exhibit low efficiency via systemic administration.
- The retention and in situ action of human A-NK cells within tumor tissue remain unclear.
- This study utilizes a xenogeneic ex vivo tissue-isolated tumor model for direct intraarterial infusion to investigate these aspects.
Purpose of the Study:
- To determine the retention efficiency of human A-NK cells within a xenogeneic tumor model.
- To investigate the in situ cytokine production of retained A-NK cells.
- To assess the infiltration capacity of A-NK cells into tumor tissue.
Main Methods:
- Human colon adenocarcinoma (HT-29) xenografts were established in nude rats and perfused ex vivo with a known number of human A-NK cells.
- Effluent cell counts and flow cytometry were used to quantify A-NK cell retention and analyze cell surface antigen expression.
- Immunohistochemistry was performed on tumor sections to detect in situ cytokine production (IL-2, IL-4, IL-10, TNF-alpha, IFN-gamma).
Main Results:
- A mean of 59.2% of infused A-NK cells were retained within the tumor post-perfusion.
- No significant changes in cellular phenotype (CD45, CD14, CD3, CD56 expression) were observed between infused and retained A-NK cells.
- Microscopic analysis revealed A-NK cell infiltration into tumor nests, and in situ immunopositivity for IL-2, IL-4, IL-10, and TNF-alpha was detected.
Conclusions:
- Human A-NK cells demonstrate efficient retention within transplanted human colon tumor tissue in this ex vivo model.
- Despite limited perfusion time, A-NK cells successfully infiltrated the tumor and initiated the production of key cytokines.
- These findings support the potential of intraarterial infusion of A-NK cells for localized tumor targeting and immune activation.