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Published on: October 2, 2012
Mechanistic Insights into Trop2 Clustering on Lung Cancer Cell Membranes Revealed by Super-resolution Imaging
Yilin Fu1, Peiyan Hua1, Yan Lou1
1The Second Hospital of Jilin University, No. 218, Ziqiang Road, Changchun, Jilin 130041, China.
Abstract:
The transmembrane glycoprotein Trop2 plays important roles in various types of human cancers, especially lung cancer. Although it has been found to form clusters on cancer cell membranes, the factors that affect its clustering are not yet fully understood. Here, using direct stochastic optical reconstruction microscopy (dSTORM), we found that Trop2 generated more, larger, and denser clusters on apical cell membranes than on basal membranes and that the differences might be related to the different membrane structures. Moreover, dual-color dSTORM imaging revealed significant colocalization of Trop2 and lipid rafts, and methyl-β-cyclodextrin disruption dramatically impaired the formation of Trop2 clusters, indicating a key role of lipid rafts in Trop2 clustering. Additionally, depolymerization of the actin cytoskeleton decreased Trop2 cluster numbers and areas, revealing that actin can stabilize the clusters. More importantly, stimulation of Trop2 in cancer cells hardly changed the cluster morphology, suggesting that Trop2 is activated and forms clusters in cancer cells. Altogether, our work links the spatial organization of Trop2 to different membrane structures and Trop activation and uncovers the essential roles of lipid rafts and actin in Trop2 cluster maintenance.
Insights
Trop2 protein forms larger, denser clusters on cancer cell apical membranes. Lipid rafts and actin cytoskeleton are essential for Trop2 clustering and stabilization in cancer cells.
Area of Science:
- Cell biology
- Cancer research
- Biophysics
Background:
- Trop2, a transmembrane glycoprotein, is crucial in human cancers, particularly lung cancer.
- Trop2 clustering on cancer cell membranes is observed, but the underlying mechanisms remain unclear.
Purpose of the Study:
- To investigate factors influencing Trop2 clustering on cancer cell membranes.
- To explore the relationship between Trop2 spatial organization, membrane structure, and Trop2 activation.
Main Methods:
- Direct stochastic optical reconstruction microscopy (dSTORM) for high-resolution imaging.
- Dual-color dSTORM to assess Trop2 colocalization with lipid rafts.
- Chemical disruption of lipid rafts (methyl-β-cyclodextrin) and actin cytoskeleton depolymerization.
Main Results:
- Trop2 formed significantly more, larger, and denser clusters on apical versus basal cell membranes.
- Trop2 exhibited significant colocalization with lipid rafts, which are critical for cluster formation.
- Actin cytoskeleton depolymerization reduced Trop2 cluster number and size, indicating a stabilizing role.
- Trop2 stimulation did not alter cluster morphology, suggesting pre-formed clusters in activated cancer cells.
Conclusions:
- Trop2 clustering is influenced by distinct membrane structures.
- Lipid rafts and the actin cytoskeleton play essential roles in Trop2 cluster formation and maintenance.
- The findings link Trop2 spatial organization to its activation and provide insights into cancer cell mechanisms.
