Targeting uptake transporters for cancer imaging and treatment

Abstract

Cancer cells reprogram their gene expression to promote growth, survival, proliferation, and invasiveness. The unique expression of certain uptake transporters in cancers and their innate function to concentrate small molecular substrates in cells make them ideal targets for selective delivering imaging and therapeutic agents into cancer cells. In this review, we focus on several solute carrier (SLC) transporters known to be involved in transporting clinically used radiopharmaceutical agents into cancer cells, including the sodium/iodine symporter (NIS), norepinephrine transporter (NET), glucose transporter 1 (GLUT1), and monocarboxylate transporters (MCTs). The molecular and functional characteristics of these transporters are reviewed with special emphasis on their specific expressions in cancers and interaction with imaging or theranostic agents [e.g., I-123, I-131, ¹²³I-iobenguane (mIBG), ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) and ¹³C pyruvate]. Current clinical applications and research areas of these transporters in cancer diagnosis and treatment are discussed. Finally, we offer our views on emerging opportunities and challenges in targeting transporters for cancer imaging and treatment. By analyzing the few clinically successful examples, we hope much interest can be garnered in cancer research towards uptake transporters and their potential applications in cancer diagnosis and treatment.

Keywords: CT, computed tomography; Cancer imaging; DDI, drug–drug interaction; DTC, differentiated thyroid cancer; FDA, U.S. Food and Drug Administrations; FDG, fluorodeoxyglucose; GLUT, glucose transporter; IAEA, the International Atomic Energy Agency; LACC, locally advanced cervical cancer; LAT, large amino acid transporter; MCT, monocarboxylate transporter; MRI, magnetic resonance imaging; NE, norepinephrine; NET, norepinephrine transporter; NIS, sodium/iodine symporter; Neuroblastoma; OCT, organic cation transporter; PET, positron emission tomography; PHEO, pheochromocytoma; RA, retinoic acid; RET, rearranged during transfection; SLC, solute carrier; SPECT, single-photon emission computed tomography; SUV, standardized uptake value; TFB, tetrafluoroborate; TSH, thyroid stimulating hormones; Thyroid cancer; Uptake transporter; Warburg effect; mIBG; mIBG, iobenguane/meta-iodobenzylguanidine; vHL, von Hippel-Lindau.