Functional expression of voltage-gated sodium channels in primary cultures of human cervical cancer.
Cervical cancer (CaC) is the third most frequent cause of death from cancer among women in the world and the first in females of developing countries. Several ion channels are upregulated in cancer, actually potassium channels have been suggested as tumor markers and therapeutic targets for CaC. Voltage-gated sodium channels (VGSC) activity is involved in proliferation, motility, and invasion of prostate and breast cancer cells; however, the participation of this type of channels in CaC has not been explored. In the present study, we identified both at the molecular and electrophysiological level VGSC in primary cultures from human cervical carcinoma biopsies. With the whole cell patch clamp technique, we isolated and identified a voltage-gated Na(+) current as the main component of the inward current in all investigated cells. Sodium current was characterized by its kinetics, voltage dependence, sensitivity to tetrodotoxin (TTX) block and dependence to [Na(+)](o). By analyzing the expression of mRNAs encoding TTX-sensitive Na(+) channel alpha subunits with standard RT-PCR and specific primers, we detected Na(v)1.2, Na(v)1.4, Na(v)1.6, and Na(v)1.7 transcripts in total RNA obtained from primary cultures and biopsies of CaC. Restriction enzyme analysis of PCR products was consistent with the molecular nature of the corresponding genes. Notably, only transcripts for Na(v)1.4 sodium channels were detected in biopsies from normal cervix. The results show for the first time the functional expression of VGSC in primary cultures from human CaC, and suggest that these channels might be considered as potential molecular markers for this type of cancer.
Diaz
Daniel
D
Departamento de Biofísica, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México. México, DF, México.
Delgadillo
Dulce Maria
DM
Hernández-Gallegos
Elizabeth
E
Ramírez-Domínguez
Martha Eugenia
ME
Hinojosa
Luz María
LM
Ortiz
Cindy Sharon
CS
Berumen
Jaime
J
Camacho
Javier
J
Gomora
Juan Carlos
JC
D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D002277:Carcinoma / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D006801:Humans; D008564:Membrane Potentials / Q000235:genetics; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism; D062553:NAV1.4 Voltage-Gated Sodium Channel; D062557:NAV1.6 Voltage-Gated Sodium Channel; D062556:NAV1.7 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D018408:Patch-Clamp Techniques; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012964:Sodium / Q000378:metabolism / Q000494:pharmacology; D026941:Sodium Channel Blockers / Q000494:pharmacology; D015222:Sodium Channels / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D002583:Uterine Cervical Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology
D014408:Biomarkers, Tumor; D009124:Muscle Proteins; D062553:NAV1.4 Voltage-Gated Sodium Channel; D062557:NAV1.6 Voltage-Gated Sodium Channel; D062556:NAV1.7 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins; D021122:Protein Subunits; D012333:RNA, Messenger; C106251:SCN4A protein, human; C100681:SCN8A protein, human; C486866:SCN9A protein, human; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D012964:Sodium