A tumour-promoting senescent secretome triggered by platinum chemotherapy exploits a targetable TGFβR1/Akt-mTOR axis in lung cancer

Platinum-based chemotherapy is commonly used for non-small cell lung cancer (NSCLC) treatment, yet clinical outcomes remain poor. Cellular senescence and its associated secretory phenotype (SASP) can have multiple tumour-promoting activities, although these are largely unexplored in lung cancer. Here we show that cisplatin-derived SASP enhances the malignant phenotype of lung cancer cells. Using xenograft, orthotopic and KrasG12V-driven murine NSCLC models, we demonstrate that cisplatin-induced senescent cells strongly promote tumour progression. Mechanistically, we find that a TGF-{beta}-enriched SASP drives pro-proliferative effects through TGF{beta}R1 and Akt/mTOR pathway activation. We validate the translational relevance of chemotherapy-induced SASP using clinical NSCLC samples from patients who received neoadjuvant platinum-based chemotherapy. Importantly, TGF{beta}R1 inhibition with galunisertib or senolytic treatment significantly reduces tumour promotion driven by cisplatin-induced senescence. Finally, we demonstrate, using distinct murine NSCLC models, that addition of TGFBR1 inhibitors to platinum-based chemotherapy reduces tumour burden and improves survival, providing pre-clinical proof-of-concept for future trial designs.