Identification of invadopodia by TKS5 staining in human cancer lines and patient tumor samples

Invadopodia, cancer cell protrusive structures with associated proteolytic activity, provide cancer cells with the ability to remodel the extracellular matrix. Invadopodia facilitate invasive migration and their formation correlates with cancer cell invasiveness and metastatic potential. The unambiguous identification of invadopodia is an important step to undergo studies on invadopodia regulatory inputs, functional outputs, as well as the prevalence and significance of invadopodia for cancer cells and human tumors. The adaptor protein TKS5 is a known invadopodia regulatory protein, which is necessary for invadopodia formation and activity. TKS5 is highly enriched at invadopodia and, unlike other commonly used invadopodia markers, it does not accumulate significantly in other types of cellular protrusions. However, the use of TKS5 as a marker of invadopodia has not been generalized, in part due to the availability of suitable antibodies against the human protein. We have evaluated two commercial antibodies raised against human TKS5. Here, we detail protocols for the detection of invadopodia-associated TKS5 in human cells in culture and in paraffin-embedded archived tumor surgical specimens using commercial antibodies. These methods should facilitate the identification and study of human invadopodia. • TKS5 staining identifies invadopodia in human cancer cell lines and archived surgical tumor specimens.