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Cx43 protein may boost breast cancer drug response in lab tests

Early results, not yet checked by other scientists · bioRxiv · Oct 28, 2026

What this means

Researchers studied a protein called Cx43 that helps cells talk to each other. They found it may help a breast cancer drug slow tumor growth. This early work is not yet checked by other scientists, so it does not show this would help people.

Plain-English summary written by an AI model from the abstract. The original is below.

Tested inPeople
Who it was tested in
Human breast cancer cells in a lab
Kind of research
Early results, not yet checked by other scientists

The science

Original title
Dual Role of Cx43 in Enhancing CDK4/6 Inhibitor Response and Promoting the Elimination of Therapy-Induced Senescent Tumor Cells
Authors
Carpintero-Fernandez, P., Barturen-Gomez, M., Alvarez, V. et al.
Journal
bioRxiv (preprint, not yet peer reviewed)
Published
Oct 28, 2026
Study type
Preprint

Abstract

Breast cancer has become the most prevalent malignancy worldwide. A key clinical advance has been the introduction of cyclin-dependent kinase 4/6 inhibitors (CDK4/6i), that in combination with endocrine therapy has been a major advance for the treatment of luminal (ER/HER2-) breast cancer. CDK4/6i induce cell cycle arrest in G1 and cellular senescence improving clinical outputs. However, limited efficacy and therapeutic resistance remain major challenges due to incomplete effects or the failure to eliminate the accumulated tumor senescent cells. Here, we identify connexin 43 (Cx43), a membrane channel protein involved in cell-to-cell communication, identified as a novel target in luminal breast cancer that potentiates the effects of CDK4/6 inhibitors. We found that Cx43 not only reduces tumor cell proliferation by enhancing senescence but also reshapes the Senescence-Associated Secretory Phenotype (SASP) profile. We also demonstrate that, in combination with CDK4/6i, Cx43 reinforces G1 arrest via transcriptional downregulation of E2F targets including CDK4 and CDK6, and through interaction with p21/p27, deepens the senescent state. Importantly, the Cx43-associated senescent phenotype sensitizes tumor cells accumulated under CDK4/6i treatment to the senolytic agent Navitoclax. Our results demonstrate that upregulation of Cx43 in breast cancer reduces proliferation and enhances the clearance of therapy-induced senescent cells. The triple-drug strategy comprising CDK4/6i, Cx43 delivery, and a senolytic drug such as Navitoclax holds great promise for overcoming CDK4/6i resistance and improving clinical outcomes in ER/HER2- breast cancer and may also be applicable to other cancer types that respond to CDK4/6i or other pro-senescence antitumoral drugs.

Read it on bioRxiv ↗

Carpintero-Fernandez, P., Barturen-Gomez, M., Alvarez, V. et al. Dual Role of Cx43 in Enhancing CDK4/6 Inhibitor Response and Promoting the Elimination of Therapy-Induced Senescent Tumor Cells. bioRxiv. 2026. doi:10.64898/2026.10.26.761820. https://doi.org/10.64898/2026.10.26.761820

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