Lack of expression of preproorexin and orexin receptors genes in human normal and prostate cancer cell lines

Introduction. Studies on expression of orexins (OXs) and their receptors in human prostate gland and human prostatic cell lines are scanty and their results contradictory. Regarding this, we carefully reinvestigated this problem on human prostatic cell lines. Material and methods. Expression of preproorexin (ppOX) (6 primer pairs), and orexin receptors 1 and 2 (OXR1, OXR2) (4 and 2 primer pairs, respectively) was assessed by conventional PCR and QPCR in human normal (PrEC, PrSc, PrSmC) and prostate carcinoma (Du145, LNCaP, and PC3) cell lines. We designed intron spanning primers and also we applied primers from earlier publications and commercially available ones. Results. With the designed primer pairs, in all studied cell lines we failed to demonstrate expression of ppOX, OXR1 and OXR2 genes at the mRNA level, while reaction products were observed in control tissues (human placenta and adrenals). Primers applied in earlier studies did not form amplification products specific for preproorexin or orexin 1 receptor. Some commercially available primers for orexin receptor 1 produced false positive results. Conclusions. We found no evidence for the presence of preproorexin–orexin receptors system genes’ mRNAs in human prostate cell lines. The reported premises for these genes’ expression in prostate and prostatic cell lines may have arisen either from the presence of non-prostate cells included in the samples or from faulty PCR settings