Internalization via Antennapedia protein transduction domain of an scFv antibody toward c-Myc protein.

We constructed a single-chain variable fragment miniantibody (G11-scFv) directed toward the transactivation domain of c-Myc, which is fused with the internalization domain Int of Antennapedia at its carboxyl terminus (a cargo-carrier construct). In ELISA experiments, an EC(50) for binding saturation was achieved at concentrations of G11-scFv-Int(-) of approximately 10(-8) M. Internalization of a fluoresceinated Fl-G11-scFv-Int(+) construct was observed in intact human cultured cells with confocal microscopy.

Sequence specific peptidomimetic molecules inhibitors of a protein-protein interaction at the helix 1 level of c-Myc.

Our work is focused in the broad area of strategies and efforts to inhibit protein-protein interactions. The possible strategies in this field are definitely much more varied than in the case of ATP-pocket inhibitors. In our previous work (10), we reported that a retro-inverso (RI) form of Helix1 (H1) of c-Myc, linked to an RI-internalization sequence arising from the third alpha-helix of Antennapedia (Int) was endowed with an antiproliferative and proapoptotic activity toward the cancer cell lines MCF-7 and HCT-116.

A retro-inverso peptide homologous to helix 1 of c-Myc is a potent and specific inhibitor of proliferation in different cellular systems.

In 1998 we reported that an L-peptide derived from H1 of c-Myc (Int-H1-S6A,F8A), linked to an internalization sequence from the third a-helix of Antennapedia, was endowed with an antiproliferative and proapoptotic activity toward a human mammary cancer cell line: The activity apparently depends upon the presence of the Myc motif. In the present work we have added new dimensions to our original findings. It is known that short retro-inverso (RI-) peptides can assume a 3D conformation very close to their corresponding L-forms and can be recognized by the same monoclonal antibody.

TIMP-2 over-expression reduces invasion and angiogenesis and protects B16F10 melanoma cells from apoptosis.

The matrix metalloproteinase (MMP) inhibitor TIMP-2 has a high specificity for gelatinase A/MMP-2. An imbalance between gelatinase A and TIMP-2 in favor of enzymatic activity is linked to the degradation of the extracellular matrix (ECM) associated with several physiologic and pathologic events, including angiogenesis, invasion and metastasis. Since TIMPs are secreted molecules, they have the potential to be used for gene therapy of certain tumors.