Elevated levels of Mucin-16 (MUC16) in conjunction with a high expression of truncated O-glycans is implicated in playing crucial roles in the malignancy of pancreatic ductal adenocarcinoma (PDAC). However, the mechanisms by which such aberrant glycoforms present on MUC16 itself promote an increased disease burden in PDAC are yet to be elucidated. This study demonstrates that the CRISPR/Cas9-mediated genetic deletion of MUC16 in PDAC cells decreases tumor cell migration. We found that MUC16 enhances tumor malignancy by activating the integrin-linked kinase and focal adhesion kinase (ILK/FAK)-signaling axis. These findings are especially noteworthy in truncated O-glycan (Tn and STn antigen)-expressing PDAC cells. Activation of these oncogenic-signaling pathways resulted in part from interactions between MUC16 and integrin complexes (α4β1), which showed a stronger association with aberrant glycoforms of MUC16. Using a monoclonal antibody to functionally hinder MUC16 significantly reduced the migratory cascades in our model. Together, these findings suggest that truncated O-glycan containing MUC16 exacerbates malignancy in PDAC by activating FAK signaling through specific interactions with α4 and β1 integrin complexes on cancer cell membranes. Targeting these aberrant glycoforms of MUC16 can aid in the development of a novel platform to study and treat metastatic pancreatic cancer.

Background/Objectives: Pancreatic ductal adenocarcinoma (PDAC) is diagnosed at a late stage with distant metastasis in an overwhelming 50% of cases, and the prognosis is poor. Treating this extremely aggressive disease with standard-of-care therapies has led to modest benefits in overall survival, mainly due to a lack of targeted early treatment modalities, as early detection has not yet been possible. Mucin-16 (MUC16) is a glycoprotein overexpressed in more than 60% of patients with PDAC and is a tumor-specific biomarker. Methods: In this study, a magnetic resonance imaging (MRI) probe to facilitate the detection of early and late lesions of PDAC is developed by conjugating a MUC16-targeted humanized antibody (huAR9.6) with gadolinium. Results: In preclinical mouse models, this MUC16-targeted MRI probe demonstrates effective contrast enhancement in early lesions of PDAC in the subcutaneous setting and allows for the detection of late-stage pancreatic cancer tumors in an orthotopic model. The probe did not induce any toxicity in vital organs at the administered doses. Conclusions: This study establishes that synthesizing a MUC16-targeted MRI probe is feasible and allows for the better high-resolution contrast enhancement of MUC16+ PDAC lesions to facilitate detection and possibly better treatment strategies.