XPack-CDKN1B Exosome Loading and Delivery

Cyclin-dependent kinase inhibitor 1B (CDKN1B) is a 22 kDa enzyme that is classified as a cell cycle inhibitor protein due to its function in preventing the activation of cyclin E-CDK2 or cyclin D-CDK4 complexes. It is additionally considered to be a tumor suppressor because of its role in negatively regulating the cell cycle.
An XPack fusion to CDKN1B was generated in the XPack Cloning vector (cat# XPAK510PA-1) and transfected into HEK-293 cells. Exosomes were isolated from the media using ExoQuick-TC® after 48 hours. A range of 5 ug to 100 ug of XPack-CDKN1B exosomes were then added to approximately 5000 HEK-293 target cells in 96-well tissue culture plates at 24 hour intervals for a total of 72 hours. Exosomes isolated from non-transfected cells were used as a controls. The rate of cell proliferation in these recipient cells was quantified using an MTT Assay (Millipore catalog # CT02) and signals were normalilzed to HEK-293 cells treated with control exosomes. The data shown below demonstrate that functional CDKN1B protein can be delivered to target cells via exosomes using the XPack technology, and futher indicates that XPack fusions retain their bioactivity upon delivery to recipient cells.