The Cellular Role of Integrin Alpha 6 in Tumor Development

The Role of Cellular Integrin Alpha 6 in Tumor Development Keywords: Humanized Model, Cancer, Integrin Alpha 6, metastasis Developing the right cancer prevention method and cure remains a high priority in cancer research. A therapeutic or diagnostic strategy that targets tumor angiogenesis (development of blood vessels) and tumor metastasis (spread of cancer cells), the two major factors enhancing tumor growth, would be an effective method. Recent studies have focused on integrins, a transmembrane cell adhesion receptor which mediates cell communication, as a potential target for tumor therapy and diagnostics. Specifically, integrin alpha 6 (ITGA6) has been implicated in tumor developmental processes such as angiogenesis and metastasis. Several human tumors like gastric, prostate, breast and ovarian cancers, exhibit increased levels of ITGA6. These increased levels of ITGA6 in tumors makes it an excellent candidate for cancer diagnostic and therapeutic strategies. Humans with ITGA6 deficiencies caused by ITGA6 mutations are more susceptible to developing cancer and have an increased risk of disease progression. Some studies have also indicated that ITGA6 is cleaved and the cleaved product of ITGA6 may serve as cue for tumor metastasis and angiogenesis. The role that ITGA6 plays in tumor developmental processes is unclear due to the lack of an in-vivo model system. In our previous work, we collected data which suggests increased levels of ITGA6 expression in host cells, leads to increased metastasis. This data also suggest that the cleavage process may aid in the metastasis process, while simultaneously the non-cleavable version of ITGA6 reduces metastasis. We found that decreasing ITGA6 expression in host cells, decreases metastasis.In the present study, we are employing a humanized animal model to study the interaction between human cancer cells and human ITGA6. This humanized model system will allow us to understand how ITGA6 affects the pathway of a single cancer cell as it engages in tumor metastasis and angiogenesis. The level of ITGA6 expression will be increased via DNA cloning, and decreased via siRNA transfections. DNA cloning will allow us to create cellular constructs such as human full length, truncated (cleaved) , and mutated ITGA6. To knock down or decrease ITGA6 expression, human PC3 cells will be transfected with ITGA6 siRNA.To make the humanized model observable under flourescent light, PC3 cells will be labeled with CM-DiI cell labeling solution (appear red) and will subsequently be injected into transgenic zebrafish expressing green fluorescent protein in their blood vessels. This design enables us to track angiogenesis and metastasis in an in-vivo system. The zebrafish model provides many advantages to the study, as zebrafish embryos are easily accessible, amenable to genetic manipulation, high resolution imaging, and provide a whole vertebrate in-vivo system for effective tumor studies and potential drug screening. Understanding the cellular role of integrin alpha 6 is required in order to develop an effective therapeutic strategy which targets ITGA6. Investigating how ITGA6 affects tumor development in the tumor microenvironment (host level) is also a key component to a complete understanding of this protein’s role in cancer progression and cancer prevention