Date of Award

5-2018

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biological Sciences

Committee Member

Dr. Yanzhang Wei, committee chair

Committee Member

Dr. Charlie Rice

Committee Member

Dr. Jeremy Tzeng

Committee Member

Dr. Xianzhong Yu

Abstract

Cancer immunotherapies using cytokines demonstrated effective in previous studies, whereas one major obstacle with the strategy is the severe side effects when administrated systemically at high doses. Additionally, cancer cells’ escape from immune destruction has brought another challenge for cytokine therapy. Current approaches to cancer immunotherapy largely involve the immune factors designed to revive endogenous immune responsiveness, which renders high-efficient gene delivery system in urgent demand. In the first phase of our study, we demonstrated that fusion protein mIL-12/FasTI, encoded by cDNA of mouse interleukin-12 and transmembrane and intracellular domains of Fas, showed enhanced NK cell activity and anti-tumor cytotoxicity in vitro when expressed by stable tumor cell clones. As the second stage of study, a lentiviral vector-based gene delivery was used to deliver the fusion gene construct directly to tumor cells. Lentiviral vectors (pLenti7.3/IL-12/FasTI or Lent-IF) were constructed and used to transduce tumor cells. Preliminary data indicates that the constructs were efficiently delivered to tumor cells as assayed by RT-PCR and immunohistochemistry (IHC). The biological functions of the constructs as delivered by lentiviral system, such as NK cell activation, caspase-3 activity, Annexin-V apoptosis detection and tumor growth in vitro, have been demonstrated with statistical significance. This study represents a further step of bifunctional fusion protein cancer immunotherapy towards patient treatment.

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