Matrix metalloproteinase 14 (MMP14) over-expression increases invasiveness and engraftment of transplanted hepatocytes

Background: Hepatocyte transplantation is a promising approach to correct hereditary metabolic liver disease. Our study describes a novel method to increase the invasiveness of transplanted cells by matrix degradation via the over-expression of matrix metalloproteinase 14 (MMP14) in transplanted cells.

Methods: The murine Mmp14 gene was cloned from the Hepa1–6 liver tumor cell line and inserted into a lentiviral vector downstream of a SFFV promoter sequence. MMP14 lentiviral vector mediated over-expression was confirmed by qPCR and Western blot in HT1080 and Hepa1–6 cells. Invasiveness of transduced cells was tested in a 3D cell culture system. One million hepatocytes from Rosa 26 mice were then transduced with MMP14 and EGFP control vectors and transplanted into NOD/SCID and FAH mice by intrasplenic injection. After 4 days of transplantation in NOD/SCID mice and after 1 month in FAH mice, liver samples were processed and analyzed for the presence of integrated transplanted cells.

Results: MMP14 transduced HT1080 and Hepa1–6 cells showed an increased ability to invade in 3D culture but not in 2D culture systems. Four days after transplantation of transduced primary hepatocytes, we detected 0.83 cells±1.1/high power field (HPF) Lac Z positive transplanted cells in the MMP14 group and 0.36 cells±0.5/HPF in the control group (p<0.05) in recipient NOD/SCID mouse livers. After one month in FAH mice 2.56 cells±2.4/HPF and 1.13 cells±1.5/HPF FAH positive cells were counted in the MMP14 and control group, respectively (p<0.05).

Conclusion: MMP14 expression increases invasiveness and engraftment of transplanted hepatocytes. Transient expression of MMP14 is a promising approach to increase efficacy of hepatocyte transplantation in patients with metabolic liver disease.