is essential for xenograft tumor development in mice injected with the human prostate cancer cell-line, LNCaP, and modulates cell migration and invasion.

BACKGROUND AND OBJECTIVE

A growing body of literature suggests modulated expression of members of the opiorphin family of genes (, and ) is associated with cancer. Recently, overexpression of was shown to be associated with prostate cancer, with evidence of a role in overcoming the hypoxic barrier that develops as tumors grow. The primary goal of the present studies was to support and expand evidence for a role of in the development and progression of prostate cancer.

MATERIAL AND METHODS

We engineered knock-out of the opiorphin gene, in LNCaP, an androgen-sensitive, human prostate cancer derived, cell-line. Using xenograft assays, we compared the ability of injected LNCaP knock-out cell-lines to develop tumors in both castrated and intact male mice with the parental LNCaP and LNCaP overexpressing cell-lines. We used RNAseq to compare global gene expression between the parental and LNCaP knock-out cell-lines. Wound closure and 3D spheroid invasion assays were used to compare cell motility and migration between parental LNCaP cells and LNCaP cells overexpressing of .

RESULTS

The present studies demonstrate that LNCaP cell-lines with consisitutive knock-out of fail to develop tumors when injected into both castrated and intact male mice. Using RNAseq to compare global gene expression between the parental and LNCaP knock-out cell-lines, we confirmed a role for in regulating molecular pathways associated with angiogenesis and tumor blood supply, and also identified a potential role in pathways related to cell motility and migration. Through the use of wound closure and 3D spheroid invasion assays, we confirmed that overexpression of in LNCaP cells leads to greater cell motility and migration compared to parental cells, suggesting that overexpression results in a more invasive phenotype.

CONCLUSION

Overall, our studies add to the growing body of evidence that opiorphin-encoding genes play a role in cancer development and progression. is essential for establishment and growth of tumors in mice injected with LNCaP cells, and we provide evidence that has a possible role in progression towards a more invasive, metastatic and castration resistant prostate cancer (PrCa).