E-Poster Presentation ESA-SRB-ANZBMS 2021

Drug targeting of Tyrosine kinase receptor c-ros-oncogene 1 (C-ROS-1) to treat pre-fusion of coronal sutures in a pre-clinical model of craniosynostosis (#43)

Esther Camp 1 2 , Peter J Anderson 2 3 , Stan Gronthos 1 2
  1. School of Biomedicine, University of Adelaide, Adelaide, South Australia, Australia
  2. Cancer Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
  3. Australian Craniofacial Unit, Women's and Children's Hospital, Adelaide, South Australia, Australia

Craniosynostosis is the premature bone fusion of the skull plates resulting from deregulated proliferation and differentiation of cranial suture osteogenic stem cells into bone. Children with craniosynostosis exhibit increased intracranial pressure leading to neurological deficits. Current treatment options rely on major invasive cranial surgery. Saethre-Chotzen syndrome (SCS), defined by a loss-of-function mutation in the TWIST-1 gene, is one of the most prevalent craniosynostosis (incidence 1/25,000 births1). One gene known to promote osteogenic differentiation of TWIST-1 haploinsufficient cranial cells is the transmembrane tyrosine kinase receptor C-ROS-1 2. In vitro studies have demonstrated a reduced osteogenic potential of these cells following inhibition of C-ROS-1 activity with the tyrosine kinase inhibitor, Crizotinib2. The present study assessed the efficacy of Crizotinib to halt premature coronal suture fusion in a pre-clinical mouse model of SCS. Crizotinib at different concentrations was administered over the calvaria of Twist-1del/+ heterozygous mice at postnatal day 8 (P8), prior to coronal suture fusion, using either a non-resorbable collagen sponge (quick drug release) or a resorbable sodium carboxymethylcellulose (CMC) microdisc (slow sustained release). Coronal suture fusion rates and bone parameters were determined by µCT and histomorphometric analysis of calvaria at P20 and P25 (post coronal suture fusion). Results demonstrated a dose dependent increase in the efficacy of Crizotinib to maintain coronal suture patency by P20, with no adverse affects to brain tissue or blood cell parameters. Moreover, Crizotinib delivered on CMC discs resulted in a greater efficacy to reduce bone formation at the coronal suture sites by P20 compared to its delivery on sponges. Whilst a single application of Crizotinib at P8 was effective at halting suture fusion, this effect was reversible and the bone inhibitory effects diminished by P25. Our findings lay the foundation for the development of a pharmacological targeted approach to treat craniosynostosis.

  1. 1. Anderson PJ, Hall CM, Evans RD, Hayward RD, Harkness WJ, Jones BM. 1997. The cervical spine in Saethre-Chotzen syndrome. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association 34(1):79-82.
  2. 2. Camp E, Anderson PJ, Zannettino ACW, Gronthos S. Tyrosine kinase receptor c-ros-oncogene 1 inhibition alleviates aberrant bone formation of TWIST-1 haploinsufficient calvarial cells from Saethre-Chotzen syndrome patients. Journal of cellular physiology. 2018;233:7320-7332.