Characterization of Palladin's Role in Breast Cancer Invasion (2008)

Undergraduates: Hannah Prentice-Dunn, Silvia Goicoechea

Faculty Advisor: Carol Otey
Department: Biology

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Palladin is a recently discovered phosphoprotein that plays an essential role in the formation of many actin-based cytoskeletal structures. Because actin and palladin are also important components of cell motility, the Otey lab set out to explore palladin’s role in the metastasis of breast cancer, using four human breast cancer cell lines that differ in their metastatic potential. Of the four lines, the MCF7 cell line has the least metastatic potential and lowest levels of palladin, and the SUM159 cell line is the most invasive and has the highest palladin levels. The correlation between high levels of palladin and high metastatic potential suggests that high levels of palladin expression might contribute to invasive motility, perhaps through the formation of podosomes. Using immunofluorescence techniques, I explored the localization patterns of palladin to ask if palladin co-localizes with other podosome markers. Alpha-actinin, cortactin, Eps8, and palladin were all stained, in fixed cells, using specific antibodies. Immunoflourescence staining revealed podosome formation in two PDBu-treated metastatic cell lines, and no podosomes in non-metastatic MCF-7 cells. The images showed alpha-actinin, cortactin, Eps8, and palladin all co-localizing with actin in podosomes, implicating their involvement in podosome formation. Thus, palladin appears to be an integral component in podosome formation, and podosomes may contribute to a mechanism allowing metastatic cells to migrate.