Pannexin1 Drives Multicellular Aggregate Compaction via a Signaling Cascade That Remodels the Actin Cytoskeleton

• Published in: The Journal of biological chemistry 2012-03, Vol.287 (11), p.8407-8416
• Main Authors: Bao, Brian A., Lai, Charles P., Naus, Christian C., Morgan, Jeffrey R.
• Format: Article
• Language: English
• Subjects: Actin; Actin Cytoskeleton - genetics; Actin Cytoskeleton - metabolism; Actomyosin - genetics; Actomyosin - metabolism; Adenosine Triphosphate - antagonists & inhibitors; Adenosine Triphosphate - pharmacology; Animals; Anti-Ulcer Agents - pharmacology; Carbenoxolone - antagonists & inhibitors; Carbenoxolone - pharmacology; Cell Line, Tumor; Connexins - genetics; Connexins - metabolism; Cytoskeleton; Drug Antagonism; Gap Junctions; Glioma - genetics; Glioma - metabolism; Mice; Multicellular; Neoplasm Proteins - genetics; Neoplasm Proteins - metabolism; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; Pannexin; Probenecid - antagonists & inhibitors; Probenecid - pharmacology; Receptors, Purinergic P2X7 - genetics; Receptors, Purinergic P2X7 - metabolism; Signal Transduction; Tumor Microenvironment; Uricosuric Agents - pharmacology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M111.306522

Pannexin 1 (Panx1) is a novel gap junction protein shown to have tumor-suppressive properties. To model its in vivo role in the intratumor biomechanical environment, we investigated whether Panx1 channels modulate the dynamic assembly of multicellular C6 glioma aggregates. Treatment with carbenoxolone and probenecid, which directly and specifically block Panx1 channels, respectively, showed that Panx1 is involved in accelerating aggregate assembly. Experiments further showed that exogenous ATP can reverse the inhibitive effects of carbenoxolone and that aggregate compaction is sensitive to the purinergic antagonist suramin. With a close examination of the F-actin microfilament network, these findings show that Panx1 channels act as conduits for ATP release that stimulate the P2X7 purinergic receptor pathway, in turn up-regulating actomyosin function. Using a unique three-dimensional scaffold-free method to quantify multicellular interactions, this study shows that Panx1 is intimately involved in regulating intercellular biomechanical interactions pivotal in the progression of cancer. Panx1 is a novel gap junction protein with tumor-suppressive properties. Panx1 channels release ATP to initiate a cascade that drives actomyosin-mediated assembly of multicellular aggregates. Expression of Panx1 can directly alter the biomechanical properties of three-dimensional tumor aggregates. Panx1 channels through P2X7 signaling help regulate three-dimensional biomechanics of tumor suppression.