三阴性乳腺癌（TNBC）是最致命、最难治疗的乳腺癌亚型之一，治疗选择有限。我们先前发现了一种仅在TNBC中存在的蛋白复合物，由缝隙连接蛋白CX26、多能性转录因子NANOG和聚集粘附激酶（FAK）组成。我们想确定CX26相互作用区域的肽模拟物是否能在临床前模型中减弱肿瘤生长。我们设计了基于CX26近膜结构区域的肽段，并使用表面等离子共振进行了与NANOG和FAK的结合实验。结合研究表明，CX26的C末端尾巴和胞内环与NANOG和FAK的结合亲和力为次微摩尔至微摩尔，并且CX26的C末端尾巴中的5个氨基酸序列（RYCSG）足以进行结合。我们使用具有细胞穿透性的Antennapedia序列改造了高亲和力的肽段，并在包括细胞增殖、肿瘤球形体形成以及体内肿瘤生长的功能性实验中进行了评估，并且测量了下游信号通路的变化。细胞穿透型CX26肽（aCx26-pep）抑制了乳腺癌干细胞的自我更新能力，同时降低了细胞核内FAK和NANOG的表达，并抑制了TNBC细胞中NANOG靶基因的表达，而对腺上皮细胞不产生影响。在体内实验证实，aCx26-pep减缓了肿瘤生长和细胞增殖，并诱导了细胞死亡。我们通过这个研究提供了一个概念验证，即基于CX26肽的策略可以抑制乳腺癌生长并改变其NANOG活性，显示出该靶向方法的治疗潜力。

Triple-negative breast cancer (TNBC) represents the most lethal and treatment-resistant breast cancer subtype with limited treatment options. We previously identified a protein complex unique to TNBC composed of the gap junction protein connexin 26 (Cx26), the pluripotency transcription factor NANOG, and focal adhesion kinase (FAK). We sought to determine whether a peptide mimetic of the interaction region of Cx26 attenuated tumor growth in pre-clinical models. We designed peptides based on Cx26 juxtamembrane domains and performed binding experiments with NANOG and FAK using surface plasmon resonance. Binding studies revealed that the Cx26 C-terminal tail and intracellular loop bound to NANOG and FAK with submicromolar-to-micromolar affinity and that a 5-amino acid sequence in the C-terminal tail of Cx26 (RYCSG) was sufficient for binding. Peptides with high affinity were engineered with a cell-penetrating antennapedia sequence and assessed in functional assays including cell proliferation, tumorsphere formation, and in vivo tumor growth, and downstream signaling changes were measured. The cell-penetrating Cx26 peptide (aCx26-pep) disrupted self-renewal while reducing nuclear FAK and NANOG and inhibiting NANOG target gene expression in TNBC cells but not luminal mammary epithelial cells. In vivo, aCx26-pep reduced tumor growth and proliferation and induced cell death. Here, we provide proof-of-concept that a Cx26 peptide-based strategy inhibits growth and alters NANOG activity specifically in TNBC, indicating the therapeutic potential of this targeting approach.