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

Abstract

BACKGROUND. Voltage-gated Na+ channel (VGSC) activity has been implicated in prostate cancer (PC) metastasis. Although VGSCs can occur as multiple-subunit assemblies, the α-subunits (VGSCαs) alone can encode functional channels. The VGSCα gene(s) responsible for the functional VGSCα 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 VGSCα 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 VGSCα 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 VGSCα 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 VGSCα 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. © 2001 Wiley-Liss, Inc.