Preparation and evaluation of bombesin peptide derivatives as potential tumor imaging agents: effects of structure and composition of amino acid sequence on in vitro and in vivo characteristics.

Objectives: Among the many clinically relevant peptide receptor systems, bombesin (BN) receptors have attracted enormous attraction due to their overexpression in various frequently occurring human tumors including breast and prostate, thus making such receptors promising targets with radiolabeled BN analogs. The present study describes the preparation and evaluation of a series of new BN derivatives as potential tumor imaging agents.

Methods: Several new BN derivatives with the common structure MAG(3)-X-BN(1-14 or 6-14), where X=Asp or Asp-Asp, were synthesized by solid-phase peptide synthesis.

Design, synthesis, radiolabeling and in vitro and in vivo characterization of tumor-antigen- and antibody-derived peptides for the detection of breast cancer.

HER2/neu and MUC1-based synthetic peptides were prepared and evaluated in an effort to develop peptide-based radiopharmaceuticals derived from tumor-associated-antigens for the detection of breast cancer. The receptors for HER2/neu and MUC1 are overexpressed in various human cancers, such as breast and ovarian cancer. The relatively low expression of these antigens on normal tissues makes them attractive targets for tumor imaging.

Preparation and in vitro and in vivo evaluation of technetium-99m-labeled folate and methotrexate conjugates as tumor imaging agents.

The cell-membrane folic acid (FA) receptors are known to be responsible for cellular accumulation of FA and FA analogs, such as methotrexate (MTX), and are overexpressed on several tumor cells. Folate, as well as antifolates (i.e.