Prostate cancer is cancer that occurs in the prostate. Prostate cancer is the second-leading cause of cancer deaths for men. Especially, Prostate cancer is one of the most common types of cancer. The morbidity/mortality of prostate cancer has increased globally in recent years. The high mortality rate closely associates with the spread of malignant cells to various tissues especially to bone. In this study, researchers reported a potent small molecule CXCR6 antagonist ML339.

CXCR6/CXCL16 axis significantly contributes to prostate cancer cell metastasis, proliferation, and subsequent bone invasion. In particular, ML339 is a selective inhibitor of CXCR6. Consistent with its solubility data, ML339 exhibits good permeability with increased pH of the donor compartment.

CXCR6 is highly expressed in prostate cancer tissues and cell lines (LNCaP and PC3), relative to normal tissue and cells. CXCR6 expression in PCa tissues correlated with higher Gleason score. Similarly, aggressive PCa cells (PC3) show high CXCR6 compared to less aggressive LNCaP. Besides, PC3 cells show higher MMPs expression compared to LNCaP cells following CXCL16 stimulation.

CXCL16 stimulation changes cytoskeletal dynamics resulting in enhanced migration, invasion, and adhesion to endothelial cells, ultimately enabling PCa cells to achieve their metastatic goal. ML339 shows good stability in human plasma, and moderate stability in mouse plasma. Moreover, ML339 represents a meaningful improvement in potency over the HTS hit compound, maintains good GPCR selectivity. Furthermore, ML339 offers an additional starting point for lead optimization efforts and eventual in vivo studies. To summarise, ML339 is the first reported selective small-molecule CXCR6 antagonist.


Paul M. Hershberger, et al. Probing the CXCR6/CXCL16 Axis: Targeting Prevention of Prostate Cancer Metastasis.