Selective tropism of liver stem cells to hepatocellular carcinoma in vivo

Abstract

Aim: To investigate the selective tropism of liver stem cells to hepatocellular carcinoma (HCC) in an animal model and its feasibility as a vector to deliver therapeutic genes for targeted therapy of HCC.

Methods: WB-F344, a kind of rat liver stem cell, was infected with recombinant virus to establish a cell line with stable, high-level expressing enhanced green fluorescent protein (EGFP). An animal model of HCC in Wistar rats was established by implanting HCC cells (CBRH7919) combined with an immunosuppressive drug. EGFP labeled liver stem cells were injected into caudal veins of the animals and distribution was observed at different time points after injection. SDF-1 and c-kit expression in non-tumor liver and tumor tissue were analysed by immunohistochemistry for the relationshiop between the expression and migration of liver stem cells. Furthermore, hepatic stem cells were injected via the portal vein, hepatic artery, caudal vein, or directly into the pericancerous liver tissue, respectively, and effects on migration, localization, and proliferation of the hepatic stem cells within the tumor tissue were observed and analyzed.

Results: Recombinant adenovirus could deliver the EGFP gene to hepatic stem cells. A new stem cell line, named WB-EGFP, was established that stably expressed EGFP. WB-EGFP cells still showed selective tropism towards HCC and EGFP expression was stable in vivo. According to immunohistochemistry results, SDF-1 may not be related to the mechanisms of tropism of hepatic stem cells. Different application sites affected the distribution of liver stem cells. Injection via the portal vein was superior with regard to selective migration, localization, and proliferation of the hepatic stem cells within the tumor tissue.

Conclusion: Liver stem cells have the biological behavior of selective migration to HCC in vivo and they could localize and proliferate within HCC tissue stably expressing the target gene. Liver stem cells are a potential tool for a targeted gene therapy of HCC.

Figure 1

Expression of EGFP by recombinant adenoviral-mediated methods: A: WB-F344 cells in culture; B: WB-EGFP cells with expression of EGFP stably (× 200).

Figure 2

Construction of HCC animal model in rats. The tumors had the histomorphic trait of HCC (HE, × 200).

Figure 3

Liver stem cells migrated to HCC lesion. Liver stem cells migrated around the margin of the lesion after implantation 4 d (Fluorescence × 40).