Preparation, Radiolabeling with Ga/Lu and Preclinical Evaluation of Novel Angiotensin Peptide Analog: A New Class of Peptides for Breast Cancer Targeting.

Aim: Angiotensin II (AngII) is known to play a significant part in the development of breast cancer by triggering cell propagation of breast cancer, tumor angiogenesis, and regulating tumor invasion and cell migration. AngII arbitrates its action via two G-protein-coupled receptors, AngII type 1 receptor (AT1) and AngII type 2 receptor (AT2). Overexpression of the AT1 receptor in breast cancer cells seems to promote tumor growth and angiogenesis, thus targeting the AT1 receptor using AngII peptide would facilitate the detection of breast carcinoma.

Development of new copper-64 labeled rhodamine: a potential PET myocardial perfusion imaging agent.

Background: Myocardial perfusion imaging (MPI) is one of the most commonly performed investigations in nuclear medicine procedures. Due to the longer half-life of the emerging positron emitter copper-64 and its availability from low energy cyclotron, together with its well-known coordination chemistry, we have synthesized Cu-labeled NOTA- and Cu-NOTAM-rhodamine conjugates as potential cardiac imaging agents using PET.

Results: Cu-NOTA- and Cu-NOTAM-rhodamine conjugates were synthesized using a traightforward and one-step simple reaction.

Synthesis, Radiolabeling, and Preclinical Evaluation of Ga/Lu-Labeled Leuprolide Peptide Analog for the Detection of Breast Cancer.

The expansion of novel and potent tumor receptor binding peptides is a promising approach for the precise targeting of various cancer. Leuprolide is a 9-residue peptide analog of gonadotropin-releasing hormone and is extensively used in the treatment of sex hormone-dependent tumors, including prostate, breast, and ovarian cancer. This preclinical study was undertaken to prepare a new radiolabeled leuprolide peptide for the detection of breast carcinoma.

A convenient and efficient total solid-phase synthesis of DOTA-functionalized tumor-targeting peptides for PET imaging of cancer.

Introduction: An efficient and cost-effective synthesis of the metal chelating agents that couple to tumor-targeting peptides is required to enhance the process of preclinical research toward the clinical translation of molecular imaging agents. DOTA is one of the most widely used macrocyclic ligands for the development of new metal-based imaging and therapeutic agents owing to its ability to form stable and inert complexes under physiological conditions. Although solid-phase synthesis compatible DOTA-tris-(t-Bu ester) is a commercial product, it is expensive and contain chemical impurities.

Development of the Tumor-Specific Antigen-Derived Synthetic Peptides as Potential Candidates for Targeting Breast and Other Possible Human Carcinomas.

The human epidermal growth factor receptor 2 (HER2) represents one of the most studied tumor-associated antigens for cancer immunotherapy. The receptors for HER2 are overexpressed in various human cancers, such as breast and ovarian cancer. The relatively low expression of this antigen on normal tissues makes it a clinically useful molecular target for tumor imaging and targeted therapy.

Preparation and and Characterization of the Tumor-specific Antigen-derived Peptide as a Potential Candidate for Targeting Human Epidermal Growth Factor Receptor 2-positive Breast Carcinomas.

Background/aim: The human epidermal growth factor receptor (HER2) is considered as one of the most well-characterized tumor-associated antigens for cancer therapy and plays an important role in the growth and progression of breast cancer. Overexpression of HER2 in various cancers and the availability of its extracellular region makes it a clinically useful target for the development of tumor-antigen specific agents. In this study, we have prepared a HER2-targeted hybrid peptide as a single-photon emission computed tomography (SPECT) imaging probe and evaluated its tumor targeting potential in subcutaneous HER2-positive breast cancer xenograft models.

Preparation and evaluation of the tumor-specific antigen-derived synthetic mucin 1 peptide: A potential candidate for the targeting of breast carcinoma.

Purpose: The goal of this study was to prepare a synthetic peptide derived from breast tumor associated antigen and to evaluate its potential as a breast cancer imaging agent.

Methods: A mucin 1 derived peptide was synthesized by solid-phase peptide synthesis and examined for its radiochemical and metabolic stability. The tumor cell binding affinity of (99m)Tc-MUC1 peptide was investigated on MUC1-positive T47D and MCF7 breast cancer cell lines.

Novel synthesis and initial preclinical evaluation of (18)F-[FDG] labeled rhodamine: a potential PET myocardial perfusion imaging agent.

Myocardial perfusion imaging is one of the most commonly performed investigations in nuclear medicine studies. Due to the clinical importance of [(18)F]-fluoro-2-deoxy-D-glucose ([(18)F]-FDG) and its availability in almost every PET center, a new radiofluorinated [(18)F]-FDG-rhodamine conjugate was synthesized using [(18)F]-FDG as a prosthetic group. In a convenient and simple one-step radiosynthesis, [(18)F]-FDG-rhodamine conjugate was prepared in quantitative radiochemical yields, with total synthesis time of nearly 20 min and radiochemical purity of greater than 98%, without the need for HPLC purification, which make these approaches amenable for automation.

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.

Synthesis and evaluation of a technetium-99m labeled cytotoxic bombesin peptide conjugate for targeting bombesin receptor-expressing tumors.

Conjugation of the cytotoxic drugs to receptor-binding peptides is an attractive approach for the targeted delivery of cytotoxic peptide conjugates to tumor cells. In an attempt to develop an efficient peptide-based radiopharmaceutical for targeting bombesin (BN) receptor-expressing tumors (i.e.

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.

Peptide-based radiopharmaceuticals: future tools for diagnostic imaging of cancers and other diseases.

Small synthetic receptor-binding peptides are the agents of choice for diagnostic imaging and radiotherapy of cancers due to their favorable pharmacokinetics. Molecular modification techniques permit the synthesis of a variety of bioactive peptides with chelating groups, without compromising biological properties. Various techniques have been developed that allow efficient and site-specific labeling of peptides with clinically useful radionuclides such as (99m)Tc, (123)I, (111)In, and (18)F.