Small-cell lung cancer (SCLC), accounting for about 20% of all lung cancers, is a particularly aggressive form of malignancy with about 80% of cases presenting in advanced stages. Early, accurate detection of SCLC, before it becomes systemic, is essential for successful treatment.
Tumor targeting with specific carriers is a promising approach that can significantly enhance the diagnostic power of imaging techniques by increasing contrast between malignant and normal tissues.
Fluorescence-based imaging provides safe, sensitive detection of malignancies. Targeted delivery of fluorophores increases sensitivity of endoscopic imaging. Conjugation of somatostatin analogs with fluorescent agents enables tumor detection by optical imaging techniques including endoscopy. The main advantages of this method are high sensitivity and outstanding spatial resolution.
In a recent work, researchers from Israel used novel backbone cyclic peptides, which function as Somatostatin receptor (SSTR) binding, tumor-targeting vectors. They synthesized novel somatostatin analogs, based on backbone cyclic peptides, and conjugated them with fluorescent agents. Nineteen conjugates differing in core peptide, length of alkyl linker and fluorescence moiety (rhodamine and fluorescein) were tested in vitro, using a receptor binding assay, and nine of the more promising conjugates were tested in vivo by fiber-optic spectrofluorimetry and quantitative spectral imaging, on an H69 human SCLC tumor mouse xenograft model.
The lead compound showed exceptional tumor/normal tissue ratios, ranging from 9 to 90, and had potential for targeting SCLC overexpressing somatostatin receptors.
The results of the study, presented in the journal Lung Cancer (available online 12 September 2005) demonstrate, for the first time, that human SCLC can be specifically targeted with high selectivity by a fluorescent bioconjugate of somatostatin analog, providing unmatched T/NT ratios.
Medindia on Lung cancer:
Lung cancer is the uncontrolled growth of abnormal cells in the lung. Majority of people who get lung cancer have been cigarette smokers, but not all people who smoke get lung cancer. And, some people who have never smoked get lung cancer. Normal lung tissue is made up of cells that are programmed by nature to create lungs of a certain shape and function.