Novel therapeutic approaches for PDAC targeting potassium channels

by Xiaoyi Shi
Doctoral thesis
Date of Examination:2023-11-10
Date of issue:2023-12-07
Advisor:Dr. Luis A. Pardo
Referee:Dr. Luis A. Pardo
Referee:Prof. Dr. Frauke Alves
Referee:Prof. Dr. Christine Stadelmann-Nessler
Persistent Address: http://dx.doi.org/10.53846/goediss-10235

 

 

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Abstract

English

Combining targeted and conventional therapies holds promise for the handling of challenging cancers. In this study, we propose the combination of the TNF-related apoptosis-inducing ligand (TRAIL) with Kv10.1-targeting agents to induce tumor-specific apoptosis. Kv10.1, undetectable in healthy tissues but expressed in a majority of tumors, including PDAC, provides a cancer cell-specific target for therapy. Additionally, we evaluated the synergy of apoptosis induction through the intrinsic and extrinsic pathways by combining the efficacies of biologicals with mitochondrial Kv1.3 channel blockers. Three improved anti-Kv10.1 antibody fusions (62-scT, D9-scT, and SNAP-scT) were produced using different eukaryotic systems, and their efficacy was assessed in 3D cultures of spheroids derived from Kv10.1- positive cell lines. Live cell imaging was used to measure spheroid size, viability, and apoptosis induction (caspase 3/7 activity). All three constructs efficiently induced apoptosis and inhibited proliferation at picomolar concentrations, with SNAP-scT showing the most significant anti-proliferative effects. Furthermore, the constructs were tested on organoids, where they accelerated cell death significantly in cancer organoids but not in normal pancreatic ones. This effect was not achieved by soluble TRAIL, prompting further applications of these constructs in vivo, and in clinical studies. We also explored the combined efficacy of the representative construct 62-scT with small molecule inhibitors targeting Kv10.1 and mitochondrial Kv1.3 blockers in PDAC spheroids. Both types of blockers showed additive effects, but indications of synergy were only observed with Kv10.1 blockers, providing hints to the mechanisms of action of the two kinds of agents. Further conformational and mechanism studies to exploit the potential synergy and enhance therapeutic effectiveness are granted.
Keywords: PDAC; Kv10.1; Kv1.3; mitoKv1.3; TRAIL; engineered biologicals; small molecule inhibitor; apoptosis
Schlagwörter: PDAC; Kv10.1; Kv1.3; mitoKv1.3; TRAIL; engineered biologicals; small molecule inhibitor; apoptosis