Photodynamic therapy (
PDT) is an established
palliative treatment for
perihilar cholangiocarcinoma that is clinically promising. However,
tumors tend to regrow after
PDT, which may result from the
PDT-induced activation of survival pathways in sublethally afflicted
tumor cells. In this study,
tumor-comprising cells (i.e., vascular endothelial cells, macrophages,
perihilar cholangiocarcinoma cells, and EGFR-overexpressing epidermoid
cancer cells) were treated with the
photosensitizer zinc phthalocyanine that was encapsulated in cationic
liposomes (ZPCLs). The post-
PDT survival pathways and metabolism were studied following sublethal (LC50) and supralethal (LC90)
PDT. Sublethal
PDT induced survival signaling in
perihilar cholangiocarcinoma (SK-ChA-1) cells via mainly HIF-1-, NF-кB-, AP-1-, and heat shock factor (HSF)-mediated pathways. In contrast, supralethal
PDT damage was associated with a dampened survival response.
PDT-subjected SK-ChA-1 cells downregulated
proteins associated with EGFR signaling, particularly at LC90.
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-associated cell types that transcriptionally regulate cell survival, proliferation, energy metabolism, detoxification,
inflammation/angiogenesis, and
metastasis. Accordingly,
tumor cells sublethally afflicted by
PDT are a major therapeutic culprit. Our multi-omic analysis further unveiled multiple druggable targets for pharmacological co-intervention.