Immuno-Isolating Dual Poly(ethylene glycol) Capsule Prevents Cancer Cells from Spreading Following Mouse Ovarian Tissue Auto-Transplantation

For female cancer survivors, premature ovarian insufficiency (POI) is a common complication of anticancer treatments. Ovarian tissue cryopreservation before treatment, followed by auto-transplantation after remission is a promising option to restore fertility and ovarian endocrine function. However, auto-transplantation is associated with the risk of re-introducing malignant cells harbored in the stroma of the ovarian autograft. To mitigate this risk, we investigated in this pilot study whether an immuno-isolating dual-layered poly(ethylene glycol)(PEG) capsule can retain cancer cells, while supporting folliculogenesis. The dual PEG capsule loaded with 1000 4T1 cancer cells retained 100% of the encapsulated cells in vitro for 21 days of culture. However, a greater cell load of 10,000 cells/capsule led to capsule failure and cells’ release. To assess the ability of the capsule to retain cancer cells, prevent metastasis, and support folliculogenesis in vivo we co-encapsulated cancer cells with ovarian tissue in the dual PEG capsule and implanted subcutaneously in mice. Control mice implanted with 2000 non-encapsulated cancer cells had tumors formed within 14 days and metastasis to the lungs. In contrast, no tumor mass formation or metastasis to the lungs was observed in mice with the same number of cancer cells encapsulated in the capsule. Our findings suggest that the immuno-isolating capsule may prevent the escape of the malignant cells potentially harbored in ovarian allografts and, in the future, improve the safety of ovarian tissue auto-transplantation in female cancer survivors.