It is estimated that early detection of pancreatic ductal
adenocarcinoma (PDAC) could increase long-term patient survival by as much as 30% to 40% (Seufferlein, T. et al.,
Nat. Rev. Gastroenterol. Hepatol.2016, 13, 74⁻75). There is an unmet need for
reagents that can reliably identify early cancerous or precancerous lesions through various imaging modalities or could be employed to deliver anticancer treatments specifically to
tumor cells. However, to date, many PDAC
tumor-targeting strategies lack selectivity and are unable to discriminate between
tumor and nontumor cells, causing off-target effects or unclear diagnoses. Although a variety of approaches have been taken to identify
tumor-targeting
reagents that can effectively direct
therapeutics or imaging agents to
cancer cells (Liu, D. et al., J. Controlled Release2015, 219, 632⁻643), translating these
reagents into clinical practice has been limited, and it remains an area open to new methodologies and
reagents (O'Connor, J.P. et al.,
Nat. Rev. Clin. Oncol. 2017, 14, 169⁻186). G protein⁻coupled receptors (GPCRs), which are key target
proteins for
drug discovery and comprise a large proportion of currently marketed
therapeutics, hold significant promise for
tumor imaging and targeted treatment, particularly for
pancreatic cancer.