Using JM2, a Cx43 mimetic peptide of Cx43 tubulin-binding domain, we confirm efficient and specific disruption of Cx43-microtubule interaction in GSCs together with decreased self-renewal abilities and enhanced killing of this cancer stem-like cell population, highlighting a novel tumorigenic role for Cx43 in GSCs, and GBM. This evidence concerns the gene GJA1 and cancer.