Dynamic dysregulation of Tenascin-X/Tenascin-C balance controlled by Transforming Growth Factor-β leads to tumor cell proliferation during pancreatic carcinogenesis

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers due to late diagnosis and poor therapeutic efficiency. Throughout PDAC progression, a dense extracellular matrix (ECM) is deposited around neoplastic cells and accompanies tumor development and aggressiveness. This significant stroma, both in terms of quantity and through its impact on tumor cells, is now considered as a target for innovative therapies to improve patient survival. Among ECM proteins, Tenascins (TNs) are a family of four glycoproteins (TNC, TNW, TNR and TNX) sharing a common modular structure, but exhibiting different expression patterns and functions depending on the physiological and physio-pathological contexts. In PDAC, TNC is up-regulated and is considered as a pro-tumorigenic actor, whereas TNX’s role remains to be elucidated. Herein, we demonstrated that unlike TNC, TNX is drastically decreased in PDAC, and that this loss is correlated with reduced patient survival. Dysregulation of the TNX/TNC balance is attributable to Transforming Growth Factor-beta (TGF-β) upregulation during pancreatic carcinogenesis. Interestingly, we found that TNX is first highly deposited in low grade lesions before being clearly decreased in later stages suggesting an elaborate stromal remodelling during PDAC development. Finally, low TNX and high TNC deposition around precursor lesions are correlated with increased preneoplastic cell proliferation. Altogether, our results (i) demonstrate the importance of Tenascin ratios during pancreatic carcinogenesis, (ii) suggest an anti-proliferative role for TNX unlike its pro-tumoral counterpart, TNC and (iii) underscore TNX and TNC as valuable targets for the development of new drugs for pancreatic cancer and/or solid tumor treatment.