Mutations in the Drosophila tricellular junction protein M6 synergize with Ras V12 to induce apical cell delamination and invasion

Significance Complications from metastasis are responsible for the majority of cancer-related deaths, yet we understand relatively little about how cells initiate metastasis and depart from their original tissues. To uncover the cellular and molecular mechanisms governing departure of a tumor cell from its tissue, we show here that, in aDrosophila cancer model, invasion can be initiated through apical delamination. Furthermore, this apical delamination occurs as a result of alterations in the junctions between three neighboring cells, termed “tricellular junctions.” This work provides evidence that apical delamination can initiate invasion in certain contexts and highlights the important role that tricellular junction integrity can play in this process.