Voltage-gated sodium channel expression and potentiation of human breast cancer metastasis.
OBJECTIVE
Ion channel activity is involved in several basic cellular behaviors that are integral to metastasis (e.g., proliferation, motility, secretion, and invasion), although their contribution to cancer progression has largely been ignored. The purpose of this study was to investigate voltage-gated Na(+) channel (VGSC) expression and its possible role in human breast cancer.


METHODS
Functional VGSC expression was investigated in human breast cancer cell lines by patch clamp recording. The contribution of VGSC activity to directional motility, endocytosis, and invasion was evaluated by in vitro assays. Subsequent identification of the VGSC alpha-subunit(s) expressed in vitro was achieved using reverse transcription-PCR, immunocytochemistry, and Western blot techniques and used to investigate VGSCalpha expression and its association with metastasis in vivo.


RESULTS
VGSC expression was significantly up-regulated in metastatic human breast cancer cells and tissues, and VGSC activity potentiated cellular directional motility, endocytosis, and invasion. Reverse transcription-PCR revealed that Na(v)1.5, in its newly identified "neonatal" splice form, was specifically associated with strong metastatic potential in vitro and breast cancer progression in vivo. An antibody specific for this form confirmed up-regulation of neonatal Na(v)1.5 protein in breast cancer cells and tissues. Furthermore, a strong correlation was found between neonatal Na(v)1.5 expression and clinically assessed lymph node metastasis.


CONCLUSIONS
Up-regulation of neonatal Na(v)1.5 occurs as an integral part of the metastatic process in human breast cancer and could serve both as a novel marker of the metastatic phenotype and a therapeutic target.
Fraser
Scott P
SP
Neuroscience Solutions to Cancer Research Group, Department of Biological Sciences, Imperial College London, UK.
Diss
James K J
JK
Chioni
Athina-Myrto
AM
Mycielska
Maria E
ME
Pan
Huiyan
H
Yamaci
Rezan F
RF
Pani
Filippo
F
Siwy
Zuzanna
Z
Krasowska
Monika
M
Grzywna
Zbigniew
Z
Brackenbury
William J
WJ
Theodorou
Dimis
D
Koyutürk
Meral
M
Kaya
Handan
H
Battaloglu
Esra
E
De Bella
Manuela Tamburo
MT
Slade
Martin J
MJ
Tolhurst
Robert
R
Palmieri
Carlo
C
Jiang
Jie
J
Latchman
David S
DS
Coombes
R Charles
RC
Djamgoz
Mustafa B A
MB
D000595:Amino Acid Sequence; D001706:Biopsy; D015153:Blotting, Western; D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D004705:Endocytosis; D004847:Epithelial Cells / Q000166:cytology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007477:Ions; D008207:Lymphatic Metastasis; D008969:Molecular Sequence Data; D062554:NAV1.5 Voltage-Gated Sodium Channel; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D018408:Patch-Clamp Techniques; D010641:Phenotype; D020033:Protein Isoforms; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015222:Sodium Channels / Q000096:biosynthesis* / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology; D015854:Up-Regulation
D007477:Ions; D062554:NAV1.5 Voltage-Gated Sodium Channel; D020033:Protein Isoforms; C568320:SCN5A protein, human; D015222:Sodium Channels; D013779:Tetrodotoxin