Invadopodia formation by bladder tumor cells

Area of Science:

• Oncology
• Cell Biology
• Cancer Metastasis

Background:

• Bladder tumor recurrence and metastasis are major causes of mortality.
• Tumor cell invasion, a critical step in metastasis, is mediated by invadopodia.
• Invadopodia formation has been documented in various cancers but not previously in bladder tumors.

Purpose of the Study:

• To investigate whether human bladder tumor cells form invadopodia.
• To determine if invadopodia formation correlates with the invasive potential of bladder tumor cells.
• To characterize the functional activity of invadopodia in bladder cancer.

Main Methods:

• Confocal laser scanning microscopy was used to visualize invadopodia.
• In vitro assays assessed Matrigel degradation activity of bladder tumor cell lines.
• Primary tumor cells from patients with invasive bladder tumors were analyzed.

Main Results:

• Invasive bladder tumor cell lines (YTS-1, T24) formed detectable invadopodia with high Matrigel degradation activity.
• Noninvasive bladder tumor cell lines (RT4, KK-47) did not form detectable invadopodia.
• Invadopodia from YTS-1 cells secreted matrix metalloproteases and degraded extracellular matrix, facilitating invasion. Primary tumor cells from invasive bladder tumors also formed invadopodia.

Conclusions:

• Human bladder tumor cells are capable of forming functionally active invadopodia.
• Invadopodia formation is associated with the invasive phenotype of bladder tumors.
• Invadopodia represent a critical mechanism for bladder tumor cell invasion and potential metastasis.