Interleukin-33 (IL-33) promotes DNA damage-resistance in lung cancer.

Resistance to DNA damage is one of the primary mechanisms by which tumor cells evade the effects of standard chemotherapeutic agents and radiotherapy. Dynamic and complex interactions between the tumor microenvironment (TME) and tumor cells critically influence the DNA damage response. Interleukin-33 (IL-33) is a multifunctional cytokine secreted at high levels in response to cellular damage and stress. Recently, increasing evidence has suggested that IL-33 plays a key role in promoting the therapeutic resistance of tumors. However, the actual source of IL-33 during cancer therapy and how IL-33 contributes to a resistant TME remain incompletely understood. In this study, we found that both cancer-associated fibroblasts (CAFs) and tumor cells treated with DNA damage-inducing agents expressed and secreted high levels of IL-33, subsequently leading to enhanced DNA damage repair efficacy. Mechanistically, nuclear IL-33 primarily functions as a transcriptional co-activator of homologous recombination repair (HRR) genes, whereas the active form of IL-33 can drive the non-homologous end joining (NHEJ) pathway via the canonical IL-33/ST2 axis. Overall, we demonstrated that IL-33 plays a key role in mediating a DNA damage-resistant TME, which could represent a potential therapeutic vulnerability in chemoresistant cancer cells.