Systemic administration of a recombinant adenovirus encoding a HSA–Angiostatin kringle 1–3 conjugate inhibits MDA-MB-231 tumor growth and metastasis in a transgenic model of spontaneous eye cancer

Abstract

We previously reported that intratumoral injection of AdK3, a recombinant adenovirus encoding human angiostatin kringle (K) 1 to 3, inhibits tumor vascularization and tumor growth. To reduce the serum clearance of this factor, we constructed an adenovirus (AdK3-HSA) that carries a chimeric gene encoding a fusion protein between angiostatin K1-3 and human serum albumin (HSA). This conjugate inhibited endothelial cell proliferation as efficiently as K1-3. K3-HSA serum concentrations in immunodeficient mice systemically injected with AdK3-HSA were dramatically higher than in AdK3-injected mice. Furthermore, the growth of MDA-MB-231 tumors grafted into nude mice that had been injected intravenously with AdK3-HSA was inhibited by 79% (versus 17% with AdK3). In TRP-1/SV40 Tag transgenic mice, which spontaneously develop eye tumors with brain metastases, intravenous injections of AdK3-HSA in newborn mice blocked metastatic dissemination efficiently and significantly, and prolonged survival by 3 weeks. After 2 months, only 46% of AdK3-HSA-treated animals developed micrometastases, whereas 94% of the AdCO1-injected group displayed numerous macrometastases. Nevertheless, ocular tumor growth was not modified because of impaired diffusion of the conjugate in the eye compartment. Our results show that HSA genetic coupling is an efficient way to increase the pharmacokinetics of circulating angiogenic inhibitors and thus their antitumoral activity.

A gene transfer comparative study of HSA-conjugated antiangiogenic factors in a transgenic mouse model of metastatic ocular cancer

“…The K1-3-HSA chimeric protein contains the native secretion signal and the first three Ks of human plasminogen, genetically fused to HSA. 10 The ATF-HSA chimeric protein contains the native secretion signal and the first 135 residues of murine urokinase (uPA) linked to 586 residues of mature HSA. 15 Can-HSA describes the C-terminal NC1 domain of the human a2 chain of type IV collagen (Can, 24 kDa) fused with HSA.…”

“…15 The fused gene K1-3-HSA contains the native signal peptide followed by the first 333 residues of mature human plasminogen (K1-3), which is genetically linked to the 586 aa of mature HSA. 10 The fused gene ES-HSA contains the murine-uPA signal peptide followed by the last 183 C-terminal residues of murine collagen XVIII, genetically linked to the 586 aa of HSA. The fused gene Can-HSA expresses (i) the PrePro signal sequence of HSA (24 residues), (ii) the Cterminal NC1 domain of the human a2 chain of type IV collagen also named Can (Can) and (iii) the 586 residues of mature HSA.…”

“…7 Angiostatin has been described to exert potent antiangiogenic and antitumor activities in a variety of murine tumor models. [7][8][9][10] Similarly, a 20-kDa (184 amino acid (aa)) C-terminal fragment of collagen XVIII, termed endostatin (ES), is reported to be a potent inhibitor of tumor angiogenesis and micrometastases development. 5,11 The urokinase plasminogen activator (uPA) binds to its receptor uPAR via its light chain fragments, 12 known as amino-terminal fragment ATF (residues .…”

“…In a previous study, we showed that genetic coupling of mATF or K1-3 of angiostatin to human serum albumin (HSA): (i) preserved their antiangiogenic properties and (ii) dramatically improved their serum half-lives. 15,10 Protein production, long-term storage of bioreactive proteins and cumbersome daily administration are serious hurdles in this context. In contrast, the antitumor effects that follow antiangiogenic gene delivery from a variety of viral and non-viral vectors in vivo highlight the potential of antiangiogenic gene therapy as an additional strategy for treatment against cancer and metastatic dissemination.…”

“…In contrast, the antitumor effects that follow antiangiogenic gene delivery from a variety of viral and non-viral vectors in vivo highlight the potential of antiangiogenic gene therapy as an additional strategy for treatment against cancer and metastatic dissemination. 10,16,17 We chose the highly efficient adenovirusbased gene delivery system to evaluate the antitumor potency of several conjugates between HSA and antiangiogenic factors (K1-3, ES, ATF and Can) in TRP-1/ SV40Tag transgenic mice, which spontaneously develop eye tumors with brain metastases. 18 Here, we present, for the first time, a comparative study of the antimetastatic and antiangiogenic activities of these fused factors in a metastatic ocular tumor model.…”