Expression of sphingosine 1-phosphate receptor 4 and sphingosine kinase 1 is associated with outcome in oestrogen receptor-negative breast cancer

Ohotski, Jan and Long, Jaclyn and Orange, Clare and Elsberger, Beatrix and Mallon, Elizabeth and Doughty, J and Pyne, Susan and Pyne, Nigel and Edwards, Joanne (2012) Expression of sphingosine 1-phosphate receptor 4 and sphingosine kinase 1 is associated with outcome in oestrogen receptor-negative breast cancer. British Journal of Cancer, 106 (8). pp. 1453-1459. ISSN 1532-1827

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Abstract

BACKGROUND: We previously reported that sphingosine 1-phosphate receptor 4 (S1P(4)) is expressed and stimulates the ERK-1/2 pathway via a human epidermal growth factor receptor 2 (HER2)-dependent mechanism in oestrogen receptor-negative (ER(-)) MDA-MB-453 breast cancer cells. METHODS: Clinical relevance of S1P(4) and sphingosine kinase 1 (SK1, which catalyses the formation of S1P) was assessed in a cohort of 140 ER(-) breast tumours by immunohistochemistry (IHC) and the weighted histoscore method. Additional evidence for a functional interaction between S1P(4) and SK1 and between HER2 and SK1 was obtained using MDA-MB-453 cells. RESULTS: High S1P(4) expression is associated with shorter disease-free (P=0.014) and disease-specific survival (P=0.004), and was independent on multivariate analysis. In addition, patients with tumours that contain high and low levels of SK1 and S1P(4), respectively, have a significantly shorter disease-free survival (P=0.043) and disease-specific survival (P=0.033) compared with patients whose tumours contain both low S1P(4) and SK1 levels. In addition, high tumour expression of SK1 was significantly associated with shorter disease-specific survival (P=0.0001) in patients with HER2-positive tumours. Treatment of MDA-MB-453 cells with the SK1 inhibitor, SKi (2-(p-hydroxyanilino)-4-(p-chlorophenyl)thiazole) reduced the basal and S1P/S1P(4)-induced activation of ERK-1/2 and altered HER2 trafficking in these cells. CONCLUSION: These findings highlight an important role for S1P(4) and SK1 in ER(-) breast cancer progression.