Life on earth imposes daily rhythms of environmental conditions such as light-dark and temperature cycles. Organisms evolved an endogenous timing system, the circadian clock that anticipates daily variations to optimize metabolism and physiology in a daily manner. Circadian clocks are self-sustainable and cell autonomous present in virtually every cell in the organism. On the molecular level, rhythms are generated by interconnected transcriptional and translational feedback loops that drive cycles of transcription, translation, protein and post-translational modification abundance. In mammals, circadian asynchrony contributes to pathological conditions such as obesity and cancer. However, to date it is not known how circadian clocks are linked to cancer progression and to what extent circadian rhythms in cancer cells or their environment can be used to tailor optimized timing across the day for therapeutic interventions (chronotherapy).

We recently discovered that certain kinases with oncogenic potential in pancreatic cancer are regulated by circadian clocks in healthy tissues, therefore this project ultimately aims to understand the interplay between circadian rhythms, kinase activities and signalling outputs in pancreatic cancer by using quantitative mass spectrometry-based proteomics and phosphoproteomics. As a first step, we used this methodology to identify metabolic pathways and signalling networks activated in a context-dependent manner in murine PDAC models driven by oncogenic KrasG12D, KrasG12D/Trp53R172H, BrafV637E and Pik3CAH1047R. Unexpectedly, we found that even close genetic backgrounds display strong divergent proteome and phosphoproteome signatures. We will study here how these context-specific activated signalling pathways crosstalk to the endogenous circadian clock in murine PDAC cell lines and tumors. Our preliminary data show that a functional clock can be retained in PDAC cell lines driven by different oncogenes. Using genetic loss of function approaches we will study how cancer progression is modulated by the presence of an endogenous clock in PDAC tumors but also by rhythmic systemic signals. We will employ proteomics and phosphoproteomics to further characterize temporally regulated signalling pathways and active kinases in those tumors that could be used as novel targets.

The long term goal will be to define the optimal timing for the delivery of drugs ensuring maximal efficiency while reducing toxicity.