Microtentacles

Microtentacles are slender, membrane-bound protrusions that extend from the surface of detached or suspended tumor cells, including circulating tumor cells. They arise in nonadherent or low-attachment conditions and are distinguished by their dynamic, elongated shape that can protrude from various regions of the cell body.

These structures are supported by cytoskeletal elements, with a notable enrichment of detyrosinated tubulin and stabilized microtubules, and they interact with intermediate filament networks such as vimentin. Actin filaments also contribute to the architecture and flexibility of microtentacles, making them dynamic and capable of rapid extension and retraction. The exact molecular composition can vary by cancer type and cellular context, but microtubule stabilization and cytoskeletal coordination are central features.

Functionally, microtentacles are believed to promote metastatic spread by enhancing the ability of detached tumor cells to reattach to vascular endothelium or extracellular matrix under fluid shear. This reattachment capacity can facilitate seeding at distant sites, contributing to the establishment of metastases. Microtentacles are therefore of interest as potential contributors to metastatic potential and as a model for studying adhesion dynamics in circulating tumor cells.

Detection and relevance: microtentacles are observed using fluorescence microscopy and live-cell imaging of detached cells, including circulating tumor cells from various cancers such as breast and prostate cancer. Their presence is investigated as a potential biomarker of aggressive disease and as a target for therapies aimed at reducing metastatic colonization. Research on microtentacles continues to illuminate how cytoskeletal dynamics influence cancer cell adhesion and dissemination.