Transcriptomic, (phospho)proteomic, and metabolomic analysis of tumor-comprising cells treated by photodynamic therapy [mouse]

Photodynamic therapy (PDT) is a tumor treatment strategy that relies on the production of reactive oxygen species (ROS) in the tumor following local illumination. Although PDT has shown promising results in the treatment of non-resectable perihilar cholangiocarcinoma, it is still employed palliatively. In this study, tumor-comprising cells (i.e., cancer cells, endothelial cells, macrophages) were treated with the photosensitizer zinc phthalocyanine that was encapsulated in cationic liposomes (ZPCLs). Post-PDT survival pathways were studied following sublethal (50% lethal concentration (LC50)) and supralethal (LC90) PDT using a multi-omics approach. ZPCLs did not exhibit toxicity in any of the cells as assessed by toxicogenomics. Sublethal PDT induced survival signaling in perihilar cholangiocarcinoma (SK-ChA-1) cells via mainly hypoxia-inducible factor 1 (HIF-1)-, nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-B)-, activator protein 1 (AP-1)-, and heat shock factor (HSF)-mediated pathways. In contrast, supralethal PDT damage was associated with a dampened survival response. (Phospho)proteomic and metabolomic analysis showed that PDT-subjected SK-ChA-1 cells downregulated proteins associated with epidermal growth factor receptor (EGFR) signaling, particularly at LC50. PDT also affected various components of glycolysis and the tricarboxylic acid cycle as well as metabolites involved in redox signaling. In conclusion, sublethal PDT activates multiple pathways in tumor parenchymal and non-parenchymal cells that, in tumor cells, transcriptionally regulate cell survival, proliferation, energy metabolism, detoxification, inflammation/angiogenesis, and metastasis. Accordingly, sublethally afflicted tumor cells are a major therapeutic culprit. Our multi-omics analysis unveiled multiple druggable targets for pharmacological intervention.

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Weijer R, Clavier S, Zaal EA, Pijls MM, van Kooten RT, Vermaas K, Leen R, Jongejan A, Moerland PD, van Kampen AH, van Kuilenburg AB, Berkers CR, Lemeer S, Heger M