The Multifaceted Roles of CXCL9 Within the Tumor Microenvironment

Chemokines are soluble proteins that orchestrate cell migration in a regulated concentration gradient. During early stages of tumor development, chemokines shape the immune landscape of tumor microenvironment. CXCL9, also known as monokine induced by gamma-interferon (MIG), can be produced during inflammatory conditions by myeloid cells within the tumor microenvironment. It attracts cells expressing the CXCR3 receptor including activated T and NK cells and has been shown to play a role in responses to immune checkpoint therapy. Overexpression of CXCL9 has also shown to reduce tumor progression and metastasis via the inhibition of angiogenesis. Conversely, CXCL9 can act directly on tumor cells expressing the CXCR3 receptor to promote cell migration and epithelial mesenchymal transition. In this chapter we discuss the anti- and pro-tumoral features of CXCL9 within the tumor microenvironment.