Antitumor activity of neurokinin-1 receptor antagonists in MG-63 human osteosarcoma xenografts

Abstract

Osteosarcoma is a highly malignant bone tumor in children and adolescents. Aprepitant is a selective high‑affinity antagonist of the human neurokinin‑1 (NK‑1) receptor (NK1R) with robust antitumor activity. No data exist on the presence of NK1R in osteosarcoma and whether this tumor responds to NK1R antagonists. Here, we analyzed the expression of NK1R in the human osteosarcoma cell line MG-63 with western blot analysis and PCR and found significant expression both at the protein and mRNA levels. We further studied the growth inhibitory capacity of aprepitant and other NK1R antagonists on MG-63 in vitro using an MTS cytotoxicity assay and DAPI staining. All antagonists induced tumor growth inhibition and apoptosis. Synergism was observed for the combination of L-733,060 with common cytostatic drugs in MG-63, but not in non-malignant HEK293 cells. Pretreatment of HEK293 with L-733,060 prior to exposure to cytostatic drugs partially protected HEK293 cells from inhibition by these drugs. Furthermore, nanomolar concentrations of substance P (SP), the natural ligand of the NK1R, increased the growth rate of MG‑63 cells and micromolar concentrations of aprepitant inhibited SP-induced growth in a dose‑dependent manner. In vivo, a xenograft for MG-63 was created in nude mice and treated with peritumoral s.c. injections of fosaprepitant, which resulted in a significant reduction of tumor volume. Collectively, we demonstrated for the first time that the NK1R is expressed in human osteosarcoma cell line MG‑63 and that this receptor can be targeted with NK1R antagonists both in vitro as well as in vivo.

Therapeutic Innovations for Targeting Hepatoblastoma

“…This was observed with doses as low as 1 μM of doxorubicin. In line with these observations, osteosarcoma cell lines showed a similar effect with NK1R antagonists for mitomycin, ifosphamide, adriamycin and cisplatin (99). What is important to point out is that, in either study, results were obtained after single treatments and are not representative of the clinical setting where several chemotherapy courses are needed.…”

“…Previous studies have unveiled other very interesting properties of these antagonists depending on the dose at which they are used. At medium doses, they can treat depression or pain, whereas, at high doses, a potent anticancer effect has been shown (98,99). Consequently, the use of NK1R antagonists bear enormous potential for future anticancer treatment strategies, knowing that many patients with cancer suffer from symptoms that could potentially be addressed simultanoulsy while causing an anticancer effect.…”

Therapeutic Innovations for Targeting Childhood Neuroblastoma: Implications of the Neurokinin-1 Receptor System

“…This latter finding identified the targeting effect of the used NK1R inhibitor to be specific (SP's is known to have a stronger binding affinity than most NK1R inhibitors, including aprepitant) (19,27). These data are in accordance with our own findings recently published for hepatoblastoma and osteosarcoma (22,23). Based on these data it is reasonable to believe that NK1R has a mitogenic role in neuroblastoma and establishes the NK1R as a novel therapeutic target for neuroblastoma.…”

“…The NK1R has become an interesting target in a large variety of childhood cancers, including several forms of leukemia, osteosarcoma, and hepatoblastoma (22)(23)(24)(25). In a recent study Henssen et al added neuroblastoma to this list (26).…”

Truncated neurokinin-1 receptor is an ubiquitous antitumor target in hepatoblastoma, and its expression is independent of tumor biology and stage

“…Aprepitant, a non-peptide NK1R antagonist, is a clinical agent approved by the Food and Drug Administration for the treatment of chemotherapy-induced nausea and vomiting. Its effects as an anticancer agent have been described extensively in vitro and in vivo (6)(7)(8)(9)(10)(11). Notably, evidence indicates that it has limited toxic side effects even when administered in high doses (6,12).…”