Role of Endothelin Axis in Head and Neck Cancer Invasion

Purpose: Head and neck squamous cell carcinoma (HNSCC) invasion and metastasis result in treatment failure and correlate with increased pain. We have previously shown that downregulation of the endothelin B receptor (ETBR) in HNSCC contributes to increased metastasis and pain, and that endothelin-1 is highly elevated in saliva of HNSCC patients. In this study we hypothesize that HNSCC invasion and pain are mediated by the “endothelin axis”, specifically through ETBR silencing coupled with endothelin A receptor (ETAR) activation by endothelin-1.  We explore the therapeutic effect of concurrent ETAR antagonism (with macitentan) and ETBR re-expression on HNSCC metastasis, perineural invasion, and pain.  

Methods: We quantified the effect of macitentan treatment and targeted ETBR re-expression on HNSCC cell invasion and proliferation, in vitro indices of metastasis and growth, using a Matrigel invasion chamber assay and the Real Time Cell Analyzer (RTCA), a high-throughput method to detect proliferation. We used real time calcium imaging to determine the effect of macitentan on activation of dissociated trigeminal neurons, the in vitro index of nociceptive signaling. We then created an HNSCC mouse model to determine the in vivoeffect of macitentan treatment on HNSCC growth and cancer-induced nociception.

Results: Macitentan treatment or ETBR re-expression alone significantly inhibited HNSCC invasion in a dose-dependent manner; macitentan combined with ETBR re-expression on cancer cells had the strongest inhibitory effect on cancer invasion. Similarly, macitentan and ETBR re-expression significantly inhibited proliferation. Real time calcium imaging showed that macitentan suppressed trigeminal neuron activation (i.e.reduced nociceptive signaling). In the HNSCC mouse model, macitentan treatment had significant anti-tumor and anti-nociceptive effects compared to control treatment.

Conclusion: Our treatment strategy of ETAR antagonism and ETBR re-expression inhibited cancer invasion and cancer-induced nociception. These promising preclinical results establish the role of the endothelin axis in HNSCC invasion and pain. Furthermore they establish the therapeutic potential of macitentan, an orally available ETAR antagonist, for HNSCC invasion and pain.

References:

1. Viet CT et al., Pain. 2011 Oct;152(10):2323-32.
2. Pickering V et al., Oral Oncol. 2007 Jan;43(1):37-41.