Aminopeptidase A is a functional target in angiogenic blood vessels.

We show that a membrane-associated protease, aminopeptidase A (APA), is upregulated and enzymatically active in blood vessels of human tumors. To gain mechanistic insight, we evaluated angiogenesis in APA null mice. We found that, although these mice develop normally, they fail to mount the expected angiogenic response to hypoxia or growth factors. We then isolated peptide inhibitors of APA from a peptide library and show that they specifically bind to and inhibit APA, suppress migration and proliferation of endothelial cells, inhibit angiogenesis, and home to tumor blood vessels. Finally, we successfully treated tumor-bearing mice with APA binding peptides or anti-APA blocking monoclonal antibodies. These data show that APA is a regulator of blood vessel formation, and can serve as a functional vascular target.

Determinants for membrane association and permeabilization of the coxsackievirus 2B protein and the identification of the Golgi complex as the target organelle.

The 2B protein of enterovirus is responsible for the alterations in the permeability of secretory membranes and the plasma membrane in infected cells. The structural requirements for the membrane association and the subcellular localization of this essential virus protein, however, have not been defined. Here, we provide evidence that the 2B protein is an integral membrane protein in vivo that is predominantly localized at the Golgi complex upon individual expression. Addition of organelle-specific targeting signals to the 2B protein revealed that the Golgi localization is an absolute prerequisite for the ability of the protein to modify plasma membrane permeability. Expression of deletion mutants and heterologous proteins containing specific domains of the 2B protein demonstrated that each of the two hydrophobic regions could mediate membrane binding individually. However, the presence of both hydrophobic regions was required for the correct membrane association, efficient Golgi targeting, and the membrane-permeabilizing activity of the 2B protein, suggesting that the two hydrophobic regions are cooperatively involved in the formation of a membrane-integral complex. The formation of membrane-integral pores by the 2B protein in the Golgi complex and the possible mechanism by which a Golgi-localized virus protein modifies plasma membrane permeability are discussed.

Studies towards the potential of poliovirus as a vector for the expression of HPV 16 virus-like-particles.

Development of human cervical carcinomas is associated with infection by certain human papillomavirus (HPV) types. Thus, protection against HPV infection through vaccination may prevent development of cervical cancer. The purpose of this study was to investigate the possibility of using a poliovirus recombinant vector to induce immunity against HPV. A poliovirus recombinant was constructed which contained the complete coding sequence of the HPV 16 major capsid protein L1, between the P1 and P2 region of the poliovirus polyprotein. A replication-competent virus was obtained after transfection of the recombinant RNA into tissue culture cells. Electron microscopically examination of cells infected with the poliovirus-HPV L1 recombinant indicated that HPV 16 L1 self-assembles into virus-like particles. To investigate the immunological response in vivo, susceptible transgenic mice carrying the poliovirus receptor were infected with the recombinant poliovirus. In all mice a modest but consistent immune response against HPV 16 was observed. Based on these results, the potential for picornavirus-derived vectors in vaccine development against HPV infection is discussed.