Document Type
Article
Publication Date
9-19-2024
Manuscript Version
vor
Abstract
Kindlin-2, an adapter protein, is dysregulated in various human cancers, including triple-negative breast cancer (TNBC), where it drives tumor progression and metastasis by influencing several cancer hallmarks. One well-established role of Kindlin-2 involves the regulation of integrin signaling, achieved by directly binding to the cytoplasmic tail of the integrin β subunit. In this study, we present novel insights into Kindlin-2’s involvement in stabilizing the β1-Integrin:TGF-β type 1 receptor (TβRI) complexes, acting as a physical bridge that links β1-Integrin to TβRI. Loss of Kindlin-2 results in the degradation of this protein complex, leading to the inhibition of downstream oncogenic pathways. We used a diverse range of in vitro assays, including CRISPR/Cas9 gene editing, cell migration, 3D-tumorsphere formation and invasion, solid binding, co-immunoprecipitation, cell adhesion and spreading assays, as well as western blot and flow cytometry analyses, utilizing MDA-MB-231 and 4T1 TNBC cell lines. Additionally, preclinical in vivo mouse models of TNBC tumor progression and metastasis were employed to substantiate our findings. Our studies established the direct interaction between Kindlin-2 and β1-Integrin and between Kindlin-2 and TβRI. Disruption of these interactions, via CRISPR/Cas9-mediated knockout of Kindlin-2, led to the degradation of β1-Integrin and TβRI, resulting in the inhibition of oncogenic pathways downstream of both proteins, subsequently hindering tumor growth and metastasis. Treatment of Kindlin-2-deficient cells with the proteasome inhibitor MG-132 restored the expression of both β1-Integrin and TβRI. Furthermore, the rescue of Kindlin-2 expression reinstated their oncogenic activities in vitro and in vivo, while Kindlin-2 lacking domains involved in the interaction of Kindlin-2 with β1-Integrin or TβRI did not. This study identifies a novel function of Kindlin-2 in stabilizing the β1-Integrin:TβRI complexes and regulating their downstream oncogenic signaling. The translational implications of these findings are substantial, potentially unveiling new therapeutically targeted pathways crucial for the treatment of TNBC tumors.
Keywords
breast cancer, extracellular signalling molecules. integrins, mechanisms of disease
Publication Title
Oncogene
Rights
© The Author(s) 2024. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Yousafzai, N.A., El Khalki, L., Wang, W. et al. Kindlin-2 regulates the oncogenic activities of integrins and TGF-β in triple-negative breast cancer progression and metastasis. Oncogene 43, 3291–3305 (2024). https://doi.org/10.1038/s41388-024-03166-2