Recent evidence suggests that the ion channel TRPA1 is implicated in lung adenocarcinoma (LUAD), where its role and mechanism of action remain unknown. We have previously established that the membrane receptor FGFR2 drives LUAD progression through aberrant protein–protein interactions mediated via its C-terminal proline-rich motif. Here we report that the N-terminal ankyrin repeats of TRPA1 directly bind to the C-terminal proline-rich motif of FGFR2 inducing the constitutive activation of the receptor, thereby prompting LUAD progression and metastasis. Furthermore, we show that upon metastasis to the brain, TRPA1 gets depleted, an effect triggered by the transfer of TRPA1-targeting exosomal microRNA (miRNA-142-3p) from brain astrocytes to cancer cells. This downregulation, in turn, inhibits TRPA1-mediated activation of FGFR2, hindering the metastatic process. Our study reveals a direct binding event and characterizes the role of TRPA1 ankyrin repeats in regulating FGFR2-driven oncogenic process; a mechanism that is hindered by miRNA-142-3p.

Lung cancer is the leading cause of cancer‐related mortality worldwide. The most common type of lung cancer is lung adenocarcinoma (LUAD) accounting for approximately 40% of all cases. Recent studies unravelled the oncogenic role of the Fibroblast Growth Factor Receptor‐2 (FGFR2) in LUAD. Moreover, it has been shown that the Transient Receptor Potential Ankyrin‐1 (TRPA1), a non‐selective cation channel commonly recognised for its role in somatosensation, is involved in lung malignancies, yet the exact mechanism of this involvement remains unknown. Thus, the aim of this study was to test for potential interaction between FGFR2 and TRPA1 in transfected HEK‐293T cells and LUAD cells as well as to map the binding sites on both proteins. Protein interaction techniques, including immunoprecipitation and Proximity Ligation Assay (PLA) in HEK‐293T cells overexpressing FGFR2 and TRPA1, revealed complex formation between the two proteins. Microscale Thermophoresis (MST) performed on purified proteins indicated direct interaction (Kd = 122.8 ± 23.4 nM) and involvement of the N‐terminal Ankyrin repeat (AR) domain of TPRA1 in the interaction with FGFR2. This result was verified by immunoprecipitation experiments performed on HEK‐293T cells overexpressing FGFR2 and truncated versions of TRPA1. On the other hand, mutations on the C‐terminal proline‐rich motif of FGFR2 pulled down TRPA1 less effectively compared to the wild type C‐terminal domain of FGFR2. These results suggest the direct binding through the AR domain of TRPA1 and the Proline‐rich motif of FGFR2. Complex formation was also shown in a LUAD cell line (HCC‐515) that endogenously expresses both proteins. In conclusion, these results describe for the first time the novel interaction between a tyrosine kinase receptor and an ion channel that could have an effect in signal transduction and subsequently in cancer progression.Support or Funding InformationUniversity of Leeds, BBSRCThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.