Role of M402, a novel heparan sulfate mimetic, in pancreatic cancer cell invasion and metastasis: Inhibition of the Sonic Hedgehog pathway and heparanase activity.

Abstract

25 Background: M402 is a novel heparin sulfate mimetic that binds to multiples growth factors, adhesion molecules, and cytokines to inhibit tumor angiogenesis, progression, and metastasis in nonclinical studies. We investigated if M402 could modulate tumor-stroma interactions in pancreatic cancer by inhibiting the Sonic Hedgehog (Shh) pathway as well as inhibit the activity of the extracellular matrix degrading enzyme, heparanase. Methods: Surface plasmon resonance (SPR) was used for analysis of M402 binding to Shh in vitro. A cell based Gli-1 reporter assay was implemented to assess the effect of M402 on Shh signaling. Immunohistochemistry and RT-qPCR were utilized to investigate M402’s effect on Shh activity in an orthotopic Capan-2 model in nude mice. The effect of M402 on heparanase activity in vitro and on Capan-2 tumor samples isolated from treated and untreated mice was measured using an HTRF-FRET assay. Results: There was specific binding of M402 to Shh in vitro. Additionally, Shh signaling was inhibited in the presence of M402. Immunohistochemistry and RT-qPCR of Capan-2 tumor samples from animals treated with M402 also demonstrated reduction of Shh signaling via Gli, its targeted transcription factor. The degree of inhibition of heparanase activity, as measured in the HTRF assay, was affected by the size, structure, and sulfation pattern of the different heparin sulfate mimetics evaluated. M402 was the most potent inhibitor of heparanse activity in vitro from all compounds tested. In addition, treatment with M402 inhibited heparanase activity in the pancreatic tumor lysates in a dose-dependent manner. Conclusions: M402 was shown in nonclinical studies to modulate tumor-stroma interactions involved in the metastatic, invasive, and desmoplastic pathways by simultaneously inhibiting two distinct pathways: Shh signaling and the activity of heparanase. M402 regulates a variety of polysaccharide-based binding proteins, which provides a rationale for the clinical investigation of M402 in a range of cancers.