1 Scientific RepoRts | 6:25650 | DOI: 10.1038/srep25650 www.nature.com/scientificreports Aberrant expression of the S1P regulating enzymes, SPHK1 and SGPL1, contributes to a migratory phenotype in OSCC mediated through S1PR2 sathya Narayanan Patmanathan 1 , Steven P. Johnson 2 , Sook Ling Lai 1 , Suthashini Panja Bernam 1 , Victor Lopes 3 , Wenbin Wei 4 , Maha Hafez Ibrahim 4 , Federico torta 5 , Pradeep Narayanaswamy 5 , Markus R. Wenk 5 , Deron R. Herr 6 , Paul G. Murray 4 , Lee Fah Yap 1 & Ian C. Paterson 1 Oral squamous cell carcinoma (OSCC) is a lethal disease with a 5-year mortality rate of around 50%. Molecular targeted therapies are not in routine use and novel therapeutic targets are required. Our previous microarray data indicated sphingosine 1-phosphate (S1P) metabolism and signalling was deregulated in OSCC. In this study, we have investigated the contribution of S1P signalling to the pathogenesis of OSCC. We show that the expression of the two major enzymes that regulate S1P levels were altered in OSCC: SPHK1 was signiicantly upregulated in OSCC tissues compared to normal oral mucosa and low levels of SGPL1 mRNA correlated with a worse overall survival. In in vitro studies, S1P enhanced the migration/invasion of OSCC cells and attenuated cisplatin-induced death. We also demonstrate that S1P receptor expression is deregulated in primary OSCCs and that S1PR2 is over-expressed in a subset of tumours, which in part mediates S1P-induced migration of OSCC cells. Lastly, we demonstrate that FTY720 induced signiicantly more apoptosis in OSCC cells compared to non-malignant cells and that FTY720 acted synergistically with cisplatin to induce cell death. Taken together, our data show that S1P signalling promotes tumour aggressiveness in OSCC and identify S1P signalling as a potential therapeutic target. Oral squamous cell carcinoma (OSCC) remains a major world health issue and is particularly prevalent in India and South East Asia. More than 250,000 new cases are diagnosed each year and, despite advances in cancer ther- apy, approximately 50% of patients die within 5 years 1 . Patients are oten given multimodal treatment comprising surgery, chemotherapy and radiotherapy 2 but loco-regional recurrences, distant metastases and second primary tumours occur frequently and are responsible for the poor patient prognosis 1 . Whilst our understanding of the molecular basis for the development of OSCC is improving 3 , molecular targeted therapies are not in routine use and new approaches to manage the disease are urgently required. Sphingosine-1-phosphate (S1P) is a bioactive lipid that is derived from its membrane-bound precursor, ceramide 4 . Ceramide is converted to sphingosine by the action of ceramidases and, subsequently, S1P is gen- erated when sphingosine is phosphorylated by activated sphingosine kinases (SPHK1 and SPHK2). S1P can 1 Department of Oral Biology and Biomedical Sciences and Oral cancer Research & coordinating centre, faculty of Dentistry, University of Malaya, 50603, Kuala Lumpur, Malaysia. 2 Dept of Molecular Genetics, the Royal Devon and Exeter Hospital, Barrack Road, Exeter, EX2 5DW, United Kingdom. 3 Department of Oral surgery, edinburgh Postgraduate Dental Institute, University of Edinburgh, Edinburgh, EH3 9HA, United Kingdom. 4 School of cancer Sciences, University of Birmingham, Birmingham, B15 2TT, United Kingdom. 5 Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 117456 Singapore. 6 Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117456 Singapore. Correspondence and requests for materials should be addressed to I.C.P. (email: ipaterson@um.edu.my) Received: 27 November 2015 Accepted: 31 March 2016 Published: 10 May 2016 OPEN