Somatostatin Receptors in Lung Cancer: From Function to Molecular Imaging and Therapeutics

Lung cancer is a deadly disease that is difficult to diagnose and even more difficult to treat effectively. Many pathways are known to affect tumor growth, and targeting these pathways provides the cornerstone by which cancer is treated. Somatostatin receptors (SSTR) are a family of G protein coupled receptors that signal to alter hormonal secretion, increase apoptosis, and decrease cellular proliferation. These receptors are expressed in many normal and malignant cells, including both small cell and non-small cell lung cancer. Synthetic analogs of SSTRs are commercially available, but their effects in lung cancer are still largely uncertain. Signaling pathway studies have shown that SSTRs signal through phosphotyrosine phosphatases to induce apoptosis as well as to decrease cell proliferation. Radiolabeled SSTR2 analogs are utilized for radiographic imaging of tumors, which, when combined with positron emission tomography-computed tomography (PET-CT) may improve detection of lung cancer. These radiolabeled SSTR2 analogs also hold promise for targeted chemotherapy as well as radiotherapy. In this review, we summarize what is known about SSTRs and focus our discussion on the knowledge as it relates to lung cancer biology, as well as discuss current and future uses of these receptors for imaging and therapy of lung cancer.