Pituitary tumor transforming gene (pttg) carboxy-terminal peptides and methods of use thereof to inhibit neoplastic cellular proliferation and/or transformation

Abstract

Disclosed is a method of inhibiting neoplastic cellular proliferation and/or transformation of mammalian cells, including cells of human origin, in vitro or in vivo. The inventive method involves the use of a pituitary tumor transforming gene carboxy-terminal peptide (PTTG-C), which has the ability to regulate endogenous pituitary, tumor transforming gene (PTTG) expression and/or function in a dominant negative manner. In some embodiments, the invention is directed to gene-based treatments that deliver PTTG-C-related polynucleotides to mammalian cells, whether in vitro or in vivo, to inhibit the endogenous expression of PTTG. Other embodiments are directed to peptide-based treatments that deliver PTTG-C peptide molecules to the cells, which inhibit endogenous PTTG expression and/or PTTG function. Additional embodiments directed to a method of inhibiting tumor angiogenesis, in vivo, are also disclosed. Also disclosed are compositions useful for inhibiting neoplastic cellular proliferation and/or transformation and tumor angiogenesis, including compositions comprising a PTTG carboxy-terminal peptide or comprising a chimeric or fusion protein that contains a first PTTG carboxy-terminal peptide segment and a second cellular uptake-enhancing and/or importation-competent peptide segment. Also disclosed are compositions comprising a PTTG carboxy-terminal-related polynucleotide, including compositions comprising expression vectors containing the PTTG-C-related polynucleotides. Kits comprising the inventive compositions are also disclosed for the treatment of neoplastic cellular proliferation in vitro or in vivo. Isolated PTTG-C peptides and PTTG-C-related polynucleotides are also disclosed, as are anti-PTTG-C-specific antibodies.