Vol. 27, No. 1, 2005 (March)
	Content

A NOVEL APPROACH TO TUMOR SUPPRESSION USING MICROENCAPSULATED ENGINEERED J558/TNF-a CELLS

Siguo Hao¹, Liping Su¹, Xulin Guo², Terence Moyana³, Jim Xiang¹

¹Department of Oncology, Research Unit, Saskatchewan Cancer Agency, University of Saskatchewan, Saskatoon, Saskatchewan S7N 4H4, Canada
²Department of Geography, Research Unit, Saskatchewan Cancer Agency, University of Saskatchewan, Saskatoon, Saskatchewan S7N 4H4, Canada
³Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, Ontario K1H 8L6, Canada

Abstract. Aim: Immunoisolation technology using microencapsulated nonautologous cells is a novel alternative approach to the treatment of cancer. The work was aimed on investigation of the effect of implantation of microencapsulates on tumor growth in vivo. Methods: In this study, we constructed an engineered tumor cell line J558/TNF-a that secreted functional tumor necrosis factor-a (TNF-a) (2 ng/ml), and went on to encapsulate the engineered cells into microencapsules. Results: Our data showed that the microencapsulates thus produced could release functional TNF-a (1.2 ng/ml), which then diffused through the microencapsule membrane into the supernatant, and produced a cytotoxic effect on L929 cells in vitro. Microencapsulated cells were intratumorally (i.t.) implanted into athymic nude mice bearing the human breast cancer MCF-7. The results showed that the i.t. implantation induced extensive tumor cell apoptosis and necrosis leading to significant tumor regression and slower tumor growth than in the control groups that were i.t. injected with microencapsulated J558 or PBS respectively (p < 0.05). Conclusion: This study provides further evidence that the microencapsulation of recombinant tumor cells secreting cytokines may be an alternative approach in treatment of cancer.

Key Words: microencapsulation, recombinant cells, TNF-a, antitumor effect.

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