Engineering of a Fully Human Anti-MUC-16 Antibody and Evaluation as a PET Imaging Agent

Abstract

Antibodies that recognize cancer biomarkers, such as MUC16, can be used as vehicles to deliver contrast agents (imaging) or cytotoxic payloads (therapy) to the site of tumors. MUC16 is overexpressed in 80% of epithelial ovarian cancer (EOC) and 65% of pancreatic ductal adenocarcinomas (PDAC), where effective ‘theranostic’ probes are much needed. This work aims to develop fully human antibodies against MUC16 and evaluate them as potential immuno-PET imaging probes for detecting ovarian and pancreatic cancers. We developed a fully human monoclonal antibody, M16Ab, against MUC16 using phage display. M16Ab was conjugated with p-SCN-Bn-DFO and radiolabeled with 89Zr. 89Zr-DFO-M16Ab was then evaluated for binding specificity and affinity using flow cytometry. In vivo evaluation of 89Zr-DFO-M16Ab was performed by microPET/CT imaging at different time points at 24–120 h post injection (p.i.) and ex vivo biodistribution studies in mice bearing MUC16-expressing OVCAR3, SKOV3 (ovarian) and SW1990 (pancreatic) xenografts. 89Zr-DFO-M16Ab bound specifically to MUC16-expressing cancer cells with an EC50 of 10nM. 89Zr-DFO-M16Ab was stable in serum and showed specific uptake and retention in tumor xenografts even after 120 h p.i. (microPET/CT) with tumor-to-blood ratios > 43 for the SW1990 xenograft. Specific tumor uptake was observed for SW1990/OVCAR3 xenografts but not in MUC16-negative SKOV3 xenografts. Pharmacokinetic study shows a relatively short distribution (t1/2α) and elimination half-life (t1/2ß) of 4.4 h and 99 h, respectively. In summary, 89Zr-DFO-M16Ab is an effective non-invasive imaging probe for ovarian and pancreatic cancers and shows promise for further development of theranostic radiopharmaceuticals.

Mesothelin-based CAR-T cells exhibit potent antitumor activity against ovarian cancer

“…Consistent with this, we performed live cell staining to find that the surface expression of MUC16 in SKOV3 cells was significantly lower, compared to OVCAR3 cells. These findings are consistent with previous studies and offer an explanation to the apparent discrepancy between the work of Zhao and colleagues and our current study [ 47 , 48 ]. Further confirmation of our hypothesis was provided by our experiments that showed that MSLN-CAR T cells could lyse SKOV3 cells that overexpressed MUC16.…”

[225Ac]Ac/[89Zr]Zr-labeled N4MU01 radioimmunoconjugates as theranostics against nectin-4 positive triple negative breast cancer

“…The binding affinity and specificity of N4MU01 were evaluated by flow cytometry using nectin-4 expressing breast cancer cells MDA-MB-468, MCF-7, 4T1. nectin-4 and nectin-4 negative MDA-MB-231 cells as described previously [21]. The detailed method is described in the supplementary section.…”

“…The internalization of N4MU01 was studied for 48 h using the Incucyte live-cell imaging system as described previously [21]. The detailed method is described in the supplementary method section.…”

MUC1 and MUC16: critical for immune modulation in cancer therapeutics

“…confirmed the significant cytotoxicity of MUC16 ectodomain-specific bispecific single-chain variable fragments (BiTEDs) against ovarian cancer cells in vitro , effectively delaying tumor progression in vivo , especially when combined with anti-angiogenic treatment, showing potential for extending survival ( 147 ). Additionally, Babeker’s team’s investigation into the fully human monoclonal antibody M16Ab in ovarian cancer immune PET imaging revealed that the 89Zr-DFO-M16Ab conjugate specifically targets MUC16-positive tumor cells, underscoring the potential of fully human antibodies in diagnostic imaging and radiopharmaceutical development ( 148 ). Rao et al.…”