Abstract
The process of entering the bloodstream, intravasation, is a necessary step in the development of distant metastases. The focus of this review is on the pathways and molecules that have been identified as being important based on current in vitro and in vivo assays for intravasation. Properties of the vasculature which are important for intravasation include microvessel density and also diameter of the vasculature, with increased intravasation correlating with increased vessel diameter in some tumors. TGFB signaling can enhance intravasation at least in part through induction of EMT, and we discuss other TGFB target genes that are important for intravasation. In addition to TGFB signaling, a number of studies have demonstrated that activation of EGF receptor family members stimulates intravasation, with downstream signaling through PI3K, N-WASP, RhoA, and WASP to induce invadopodia. With respect to proteases, there is strong evidence for contributions by uPA/uPAR, while the roles of MMPs in intravasation may be more tumor specific. Other cells including macrophages, fibroblasts, neutrophils, and platelets can also play a role in enhancing tumor cell intravasation. The technology is now available to interrogate the expression patterns of circulating tumor cells, which will provide an important reality check for the model systems being used. With a better understanding of the mechanisms underlying intravasation, the goal is to provide new opportunities for improving prognosis as well as potentially developing new treatments.
Keywords: intravasation, metastasis, TGFB, EGFR, uPA, angiogenesis
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4967137/
Tumor cell intravasation
Tumor cell intravasation
Debbie
Protein Tyrosine Phosphatases in Tumor Progression and Metastasis: Promoter or Protection?
Abstract
Reversible phosphorylation of proteins, executed by kinases and phosphatases, is the major posttranslational protein modification in eukaryotic cells, causing them to become activated or deactivated. This intracellular event represents a critical regulatory mechanism of several signaling pathways and can be related to a broad number of diseases, including cancer. Few decades ago, protein tyrosine phosphatases (PTPs) were considered as tumor suppressors. However, nowadays, accumulating evidence demonstrates that a misregulation of PTP activities plays a crucial and decisive role in cancer progression and metastasis. In this chapter, we will focus on the molecular aspects that support the crucial role of PTPs in cancer and in turn make them promising for prediction, monitoring, and rational appropriate therapy selection of individual patients.
https://www.intechopen.com/online-first ... protection
Reversible phosphorylation of proteins, executed by kinases and phosphatases, is the major posttranslational protein modification in eukaryotic cells, causing them to become activated or deactivated. This intracellular event represents a critical regulatory mechanism of several signaling pathways and can be related to a broad number of diseases, including cancer. Few decades ago, protein tyrosine phosphatases (PTPs) were considered as tumor suppressors. However, nowadays, accumulating evidence demonstrates that a misregulation of PTP activities plays a crucial and decisive role in cancer progression and metastasis. In this chapter, we will focus on the molecular aspects that support the crucial role of PTPs in cancer and in turn make them promising for prediction, monitoring, and rational appropriate therapy selection of individual patients.
https://www.intechopen.com/online-first ... protection
Debbie