The involvement of K(v)3.4 voltage-gated potassium channel in the growth of an oral squamous cell carcinoma cell line.

Abstract

In our previous study, an A-type voltage-gated K(+) channel, K(v)3.4, was found more frequently expressed in oral squamous cell carcinoma (OSCC) when compared with non-cancerous matched oral tissue. An OSCC cell line, OECM-1, was found to have moderate level of K(v)3.4 expression. To further elucidate the roles of K(v)3.4 for the involvement of neoplastic process, we amplified K(v)3.4 coding sequence by reverse transcriptase polymerase chain reaction (RT-PCR), constructed an expression vector carrying this sequence and then stably transfected into OECM-1 OSCC cells. We demonstrated the integration and constitutive expression of K(v)3.4 in the cell. A unique A-type current elicited by such expression in OECM-1 cells was defined by patch clamp analysis. This current pattern can be reversibly blocked by an A-type K(+) channel blocker 2 mM 4-aminopyridine (4-AP). The acquisition of K(v)3.4 activity in OECM-1 cells bestowed growth advantage. However, in 3T3 cell, transfected K(v)3.4 caused only limited increase of growth without forming transformation foci. The present study established a stable keratinocyte system carrying functional K(v)3.4 and increase of growth, by which the anti-K(v)3.4 modalities for potential OSCC control can be further investigated.