固態惡性腫瘤的生長要超過2 mm ~ 3 mm的大小並且轉移至其它器官，就必需要仰賴血管的新生。目前已經有文獻在各種動物實驗裡證明抗血管新生藥物(例如endostatin 及 angiostatin)能有效抑制腫瘤的生長與轉移。本研究首要的目標就是要探討以桿狀病毒為基因載體表現抗血管新生藥物(human Endo::Angio fusion protein)，並應用於腫瘤治療的可行性。我們首先建構兩株重組桿狀病毒：Bac-hEA，這是以人類巨細胞病毒啟動子來轉錄human Endo::Angio fusion gene的桿狀病毒，另一株是Bac-ITR-hEA，在Bac-hEA的基因序列兩端加上腺相關病毒的ITR (inverted terminal repeats)序列。我們發現經由Bac-ITR-hEA桿狀病毒轉導HEK 293細胞可以加強表現human Endo::Angio fusion protein，並且以此條件培養液(conditioned medium)可以抑制人類臍帶靜脈內皮細胞(HUVEC)的增生、轉移與分化成血管狀結構的能力。另外也在動物實驗的部分與控制組相比，確認了經過注射Bac-hEA與Bac-ITR-hEA之後，裸鼠血清內hEA的表現量有明顯提升。而在腫瘤測量中得知Bac-hEA與Bac-ITR-hEA可以抑制腫瘤的生長，體積分別只有控制組的68 %與57 %。這也證明了昆蟲桿狀病毒應用在基因治療癌症的可行性。

The growth and development of solid tumors is critically dependent on angiogenesis in the absence of which tumors remain dormant and unable to metastasize. It is established that administration of angiogenesis inhibitor (e.g. endostatin or angiostatin) results in the inhibition of angiogenesis and tumor development in animal models. The primary objective of this study is to explore the feasibility of inhibiting tumor growth via the delivery of endostatin-angiostatin (Endo::Angio) fusion gene by baculovirus, which is an insect virus and emerges as a new gene therapy vector in recent years. We first constructed two recombinant baculoviruses: Bac-hEA harboring the Endo::Angio fusion gene under the transcriptional control of cytomegalovirus immediate-early promoter, and Bac-ITR-hEA harboring the same transgene cassette flanked by the adeno-associate virus (AAV) inverted terminal repeats (ITRs). Transduction of HEK293 cells with these two baculoviruses reveals enhanced expression of the Endo::Angio fusion protein by the flanking ITRs. The biological functions of the fusion protein in inhibiting blood vessel formation were confirmed in vitro by cell proliferation assay, HUVEC migration assay and tubular network formation assay. To test the efficacy the recombinant baculoviruses for cancer therapy, the tumor models were created by injecting 107 SKOV3 cells into the back of nude mice, and the baculoviruses (109 pfu) were injected into the muscle of the mouse models after the tumor developed. Strikingly, injection with Bac-ITR-hEA led to a higher degree of tumor growth inhibition compared with the injection with either Bac-hEA or phosphate buffered-saline (PBS), as evidenced by the reduced tumor volume and higher survival rate. Taken together, this study demonstrates that baculovirus can be a new gene delivery vector for cancer therapy.

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