Expression profiles of voltage-gated Na+ channel α-subunit genes in rat and human prostate cancer cell lines

BACKGROUND. Voltage-gated Na+ channel (VGSC) activity has been implicated in prostate cancer (PC) metastasis. Although VGSCs can occur as multiple-Subunit assemblies, the a-subunits (VGSC alphas) alone can encode functional channels. The VGSC alpha gene(s) responsible for the functional VGSCa expression in strongly metastatic PC cell lines is not known. METHODS. Two reverse transcription-PCR (RT-PCR) methods, degenerate primer screening and a novel semi quantitative PCR (SQT-PCR) technique, were used. These methods enabled a detailed qualitative and quantitative investigation of VGSCa mRNA expression in rat (MAT-LyLu/AT-2) and human (PC-3/LNCaP) PC cells of markedly different metastatic potential. RESULTS. Expression of eight different VGSCa genes (SCN1A-4A, SCN7A-9A, and SCN11A) was determined in the PC cell lines. Most were expressed as multiple splice variants. SQT-PCR results were consistent with a basal level of VGSCa mRNA expression occurring in weakly metastatic (AT-2/LNCaP) cells, and this being greatly elevated in cells of stronger metastatic potential (MAT-LyLu/PC-3), primarily due to the elevated expression of the SCN9A gene (also termed PN1/hNe-Na). CONCLUSIONS. (1) Several VGSCa genes and their splice variants are expressed similarly in both rat and human PC cell lines. (2) Expression levels are much higher in the strongly metastatic (MAT-LyLu/PC-3) cells. (3) Levels of SCN9A mRNA specifically are predominant in MAT-LyLu and PC-3 cells; thus, SCN9A is highly likely to be the main source of the functional VGSC detected.