Endoglin, a Novel Biomarker and Therapeutical Target to Prevent Malignant Peripheral Nerve Sheath Tumor Growth and Metastasis

Abstract

Purpose: Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive soft-tissue sarcomas that lack effective treatments, underscoring the urgent need to uncover novel mediators of MPNST pathogenesis that may serve as potential therapeutic targets. Tumor angiogenesis is considered a critical event in MPNST transformation and progression. Here, we have investigated whether endoglin (ENG), a TGF-β coreceptor with a crucial role in angiogenesis, could be a novel therapeutic target in MPNSTs. Experimental Design: ENG expression was evaluated in human peripheral nerve sheath tumor tissues and plasma samples. Effects of tumor cell-specific ENG expression on gene expression, signaling pathway activation and in vivo MPNST growth and metastasis were investigated. The efficacy of ENG targeting in monotherapy or in combination with MEK inhibition was analyzed in xenograft models. Results: ENG expression was found to be upregulated in both human MPNST tumor tissues and plasma circulating small extracellular vesicles. We demonstrated that ENG modulates Smad1/5 and MAPK/ERK pathway activation and pro-angiogenic and pro-metastatic gene expression in MPNST cells and plays an active role in tumor growth and metastasis in vivo. Targeting with ENG-neutralizing antibodies (TRC105/M1043) decreased MPNST growth and metastasis in xenograft models by reducing tumor cell proliferation and angiogenesis. Moreover, combination of anti-ENG therapy with MEK inhibition effectively reduced tumor cell growth and angiogenesis. Conclusions: Our data unveil a tumor-promoting function of ENG in MPNSTs and support the use of this protein as a novel biomarker and a promising therapeutic target for this disease.

MerTK Drives Proliferation and Metastatic Potential in Triple-Negative Breast Cancer

“…Unfortunately, the phase 3 trial evaluating TRC105 in combination with Votrient (pazopanib)-a small molecule multikinase inhibitor that primarily inhibits VEGFRs, did not show greater benefit in patients with advanced or metastatic angiosarcoma [58]. A recent xenograft study showed that combination treatments with TRC105 and PD901 (anti-MEK) inhibited soft-tissue sarcomas and concluded ENG would be a promising therapeutic target [59]. Since targeting MerTK in TNBC with different inhibitors has shown promising results [21], evaluating therapeutic strategies simultaneously targeting MerTK and ENG may be a promising avenue for the treatment of TNBC patients.…”