Panoply™ Human IL33 Over-expressing Stable Cell Line

Interleukin-33 (IL-33) plays multifaceted roles in tumor progression, yet the mechanism by which it regulates breast cancer stemness and metastasis via the Wnt pathway-specifically through autocrine signaling-remains unclear. Here, researchers found that elevated IL-33 levels correlate with aggressive breast cancer subtypes and poor prognosis. In 4T1 and MDA-MB-231 cells, IL-33 overexpression enhanced cell proliferation, migration, and the expression of cancer stem cell (CSC) markers (such as CD44 and ALDH1); conversely, knocking down ST2 using CRISPR or adeno-associated virus (AAV) inhibited tumor growth and metastasis in vivo and reduced the proportion of CSCs. Mechanistic studies revealed that IL-33 promotes stemness by activating the Wnt/β-catenin signaling pathway, an effect that could be reversed by the Wnt inhibitor XAV-939. Single-cell analysis demonstrated that IL-33 overexpression shifted the immune microenvironment toward an immunosuppressive state, whereas ST2 knockdown restored anti-tumor immune responses. This study confirms that the IL-33-Wnt axis is a key driver of breast cancer aggressiveness and proposes a novel therapeutic strategy based on AAV-mediated ST2 silencing. Targeting this axis offers the potential for dual benefits-inhibiting stemness while enhancing immune surveillance-making it a promising candidate for clinical exploration in the treatment of advanced breast cancer.

A preliminary screening of IL-33 and ST2 mRNA and protein expression across various murine and human breast cancer cell lines revealed that both proteins were expressed in all lines, albeit at varying levels. Given that murine 4T1 cells and human MDA-MB-231 cells exhibited the highest levels of IL-33 and ST2/IL1RL1 expression, these two cell lines were selected for subsequent in vitro studies. Stable IL-33-overexpressing cell lines were generated and validated using qRT-PCR and Western blot analysis. Subsequently, a series of functional assays-including CCK-8 proliferation assays, wound-healing assays, and Transwell invasion assays-were performed on the IL-33-overexpressing cells and control cells. The results demonstrated that, compared to control cells, the IL-33-overexpressing tumor cells exhibited significantly enhanced proliferation, migration, and invasion capabilities (Figure 1A-C). Similar results were observed in the MCF-7 and SK-BR3 cell lines. To evaluate the role of IL-33 in vivo, an orthotopic breast cancer transplantation model was established using female BALB/c mice. Tumor progression was monitored through regular tumor volume measurements and bioluminescence imaging. Analysis after one month revealed that Il33 knockout reduced tumor volume and weight, whereas Il33 overexpression promoted tumor growth and metastasis (Figure 1D-G).

Figure 1. IL-33 promotes breast cancer progression and metastasis. (Fan G, et al., 2025)