Elucidating the involvement of the Src Kinase substrates, Tks4 and Tks5, in mechanisms of tumor dormancy, progression and metastasis

Ronn is working on several breast cancer cell lines in vitro, using 2D and 3D cell culture techniques to define the role of Tks5 in the formation of invadopodia and in the ECM. Ronn has developed several human Tks5 monoclonal antibodies for use in our research. These antibodies are opening a new world of understanding regarding the cellular localization and roles of Tks5 in cancer cells.
Breast Cancer cells stained with Actin, Tks5 and DAPI. Yellow puncta (merge) indicate invadopodia structures.

Kinases important for functional invadopodia formation in cancer progression. 

Shinji is researching invadopodia-related kinases that have been identified using high content invadopodia screening assay. Currently these candidate kinases are being validated in several cancer types and will be assessed as cancer therapeutic target.

The adaptor protein Tks5 is a critical molecule for invadopodia formation. 

Shinji is also studying the role of invadopodia in cancer progression, especially melanoma and breast cancer, using a mouse model to reveal the role of invadopodia in cancer progression in vivo. 

ventral actin puncta

Understanding the role of Src kinase in cell cycle progression in estrogen receptor-positive breast cancer using an in vitro cell culture system and an in vivo xenograft model

Although canonical estrogen signaling in estrogen receptor-positive (ER+) breast cancer has been the focus of numerous studies, we are focusing on the role of Src kinase as a mediator of non-genomic estrogen signaling. Our lab previously showed that Src family kinases (SFKs) are involved in peptide growth factor-mediated cell cycle progression in fibroblasts, and our initial findings suggest the same is true in estrogen-positive breast cancer. We aim to understand the molecular mechanism of estrogen-dependent, Src-mediated cell cycle progression in ER+ breast cancer through in vitro studies as well as test the effects of Src inhibitors in human xenograft mouse models. We hypothesize that these signaling pathways will elucidate novel targets and potential therapeutic targets for ER+ breast cancer patients.
Understanding the role of Src kinase in cell cycle progression in estrogen receptor-positive breast cancer.

The role of macrophage Tks5 during mammary gland development and breast cancer progression

Macrophages are the most abundant leukocyte in breast tumors and an increased presence has been associated with worse survival in breast cancer patients. Macrophages are well known to produce podosomes, but the role of macrophage podosomes during breast cancer progression is not well established. Arthur utilizes mouse models to specifically ablate Tks5 in the monocyte/macrophage lineage and combines these with mouse models of breast cancer, allowing him to study the role of Tks5/podosomes during breast cancer progression. In addition, macrophages are crucial for normal mammary gland development and tumor-associated macrophages may adopt these developmental pathways. Arthur is therefore also interested in the role of macrophage podosomes during the different stages of mammary gland development.

An inducible melanoma mouse model to determine whether primary melanoma tumor growths require invadopodia and Tks5

Invadopodia are involved in most steps of tumor cell metastasis, including basement membrane degradation, local ECM remodeling and invasion, intravasation into blood vessels, extravasation out of blood vessels, and growth at metastatic sites. In our lab, we have directly shown that melanoma growth and metastasis require Tks5 and invadopodia;however, these experiments utilize cell lines derived from tumors that have already metastasized. It remains unknown whether primary tumor growth requires invadopodia and Tks5. To address this question, Elyse is using the well-established, inducible, Braf/Pten metastatic melanoma mouse model in conjunction with the loss of Tks5. Our Tks5-melanoma mouse model will enhance our understanding of whether or not invadopodia contribute to primary melanoma tumor formation;these insights will be useful in understanding how to target primary tumor growth to prevent a metastatic phenotype.

Understanding the role of vemurafenib sensitivity in melanoma invadopodia formation, invasion capability and growth in 3D collagen

Over 50% of cutaneous melanomas harbor a mutation in BRAF. Vemurafenib, a well-tolerated, competitive small-molecule inhibitor of BRAFV600E-mutant melanomas, was FDA-approved in 2011 to treat late-stage metastatic melanoma. However, most patients acquire resistance to the drug within six months of beginning treatment, provoking research on resistance mechanisms and possible combination therapies to alleviate such resistance. Intriguingly, numerous studies have reported that vemurafenib-resistant melanoma cells are more invasive than their drug-naïve counterparts in vitro, providing evidence that invadopodia may play significant roles in how vemurafenib-resistant melanomas achieve resistance and become more aggressive, metastatic tumors. Elyse is working with four different sets of melanoma cell lines, each with a vemurafenib-sensitive and a vemurafenib-resistant counterpart, in order to understand how vemurafenib resistance impacts Tks5 expression, invadopodia formation, invasion and 3D growth capabilities. Understanding how vemurafenib-resistant melanomas grow, invade and metastasize will be important in developing targeted combination therapies to improve the efficacy and overall outcome of vemurafenib treatment in metastatic melanoma patients.

Elyse Mouse Diagram

Elyse Graph

Eugene is studying the role of invadopodia in proliferation of breast cancer cells in 3D, identifying invadopodia regulated genes, and assessing the role of invadopodia in drug resistance.

 Eugene Graph