Cancer is a leading cause of death. In fact, cancer killed over 8 million people around the world in 2012. Over 90% of these cancer deaths are due to metastasis, which results from tumor cell migration and invasion. Specific cancer biomarkers need to be identified in order to effectively target these motile cells. The transmembrane glycoprotein receptor podoplanin (PDPN) promotes tumor cell motility and metastasis in many aggressive cancers. Indeed, PDPN has emerged as a prime cancer biomarker and chemotherapeutic target. Here, we describe how PDPN can be targeted to inhibit the growth and motility of melanoma and oral cancer cells. PDPN has a short intracellular domain of 9 amino acids which include two conserved serine residues. PDPN also has a large extracellular domain that is extensively O-glycosylated with α2,3-sialic acid linked to galactose. We are developing novel methods to target the intracellular and extracellular domains of PDPN to combat cancer progression. For example, we have found that some activators of protein kinase A can induce phosphorylation of the intracellular serine residues of PDPN to inhibit tumor cell migration. In addition, we have found that Maackia amurensis seed lectin (MASL) can target the extracellular domain of PDPN to inhibit tumor cell growth, migration, and tumor progression in cell culture and animal models. Furthermore, we utilized live cell imaging to find that PDPN expression can be modulated in cancer associated fibroblasts to inhibit neighboring tumor cell migration and survival. Thus, reagents can be used to target PDPN from inside of the cell and outside of the cell to inhibit tumor cell migration and combat cancer progression. This work illuminates novel strategies designed to exploit PDPN as a functionally relevant biomarker and chemotherapeutic target.

Citation Format: Harini Krishnan, Jhon Ochoa-alvarez, Yongquan Shen, Evan Nevel, David Kephart, Angels Nguyen, Min Han, Nimish Acharya, Robert Nagele, Maria Ramirez, W. Todd Miller, Evelyne Kalyoussef, Soly Baredes, Mahnaz Fatahzadeh, Lasse Jensen, Alan Shienbaum, Gary Goldberg. Podoplanin (PDPN): novel biomarker and chemotherapeutic target. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4375. doi:10.1158/1538-7445.AM2015-4375