Gene

Induced pluripotent stem cell

Cancer

Embryonic stem cell

Focal adhesion

Gap junction

Homeobox protein NANOG

Triple-negative breast cancer

Connexin

Stem cell

Cancer research

Breast cancer

Genetics

Cancer stem cell

Signal transduction

Intracellular

Transcription factor

Biology

Cell biology

Nature Communications

Tumors adapt their phenotypes during growth and in response to therapies through dynamic changes in cellular processes. Connexin proteins enable such dynamic changes during development, and their dysregulation leads to disease states. The gap junction communication channels formed by connexins have been reported to exhibit tumor-suppressive functions, including in triple-negative breast cancer (TNBC). However, we find that connexin 26 (Cx26) is elevated in self-renewing cancer stem cells (CSCs) and is necessary and sufficient for their maintenance. Cx26 promotes CSC self-renewal by forming a signaling complex with the pluripotency transcription factor NANOG and focal adhesion kinase (FAK), resulting in NANOG stabilization and FAK activation. This FAK/NANOG-containing complex is not formed in mammary epithelial or luminal breast cancer cells. These findings challenge the paradigm that connexins are tumor suppressors in TNBC and reveal a unique function for Cx26 in regulating the core self-renewal signaling that controls CSC maintenance.

Cx26 drives self-renewal in triple-negative breast cancer via interaction with NANOG and focal adhesion kinase