High expression of large-conductance Ca2+-activated K+ channel in the CD133+ subpopulation of SH-SY5Y neuroblastoma cells.
Solid tumors contain a population of cancer stem cells (CSCs), and CD133 is widely used as a CSCs marker. We investigated the differences between CD133(+) and CD133(-) cells from the neuroblastoma cell line SH-SY5Y in terms of the expressions of voltage-gated ion channels. A CD133(+) enriched (>60%) population was isolated, and a subsequent whole-cell voltage-clamp study showed that these cells predominantly express TEA-sensitive outward K(+) currents (I(K,TEA)) and TTX-sensitive voltage-gated inward Na(+) currents (I(Na)). Cell-attached single channel recordings demonstrated higher density of large-conductance (155pS) channel in CD133(+) cells than in CD133(-) cells. The TEA-sensitivity and single channel conductance indicated the large-conductance Ca(2+)-activated K(+) channels (BK(Ca)). Furthermore, RT-PCR analysis of 22 transcripts of voltage-gated ion channels in SH-SY5Y cells showed the expressions of Cav1.3, Kir2.1, Kv1.4, Kv2.1, Kv4.2, Kv7.1, BK(Ca), and Nav1.7, and those of BK(Ca) and Nav1.7 were higher in CD133(+) than in CD133(-) cells. In addition, the increase of cytosolic Ca(2+) concentration ([Ca(2+)](c)) in response to ionomycin (a Ca(2+) ionophore) was higher and more sustained in CD133(+) than in CD133(-) cells. Plausibly membrane hyperpolarization via BK(Ca) might be responsible for the augmented Ca(2+) influx observed in CD133(+) cells. The physiological implications of the differential expression of BK(Ca) and Nav1.7 in CSCs require further investigation.
Park
Ji Hyun
JH
Institute Division of Molecular and Life Sciences, Hanyang University, Ansan, Republic of Korea.
Park
Su Jung
SJ
Chung
Mi Kyung
MK
Jung
Kyoung Hwa
KH
Choi
Mi Ran
MR
Kim
Yangmi
Y
Chai
Young Gyu
YG
Kim
Sung Joon
SJ
Park
Kyoung Sun
KS
D000071916:AC133 Antigen; D015703:Antigens, CD / Q000032:analysis; D002118:Calcium / Q000378:metabolism*; D045744:Cell Line, Tumor; D006023:Glycoproteins / Q000032:analysis; D006801:Humans; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000096:biosynthesis*; D062556:NAV1.7 Voltage-Gated Sodium Channel; D014411:Neoplastic Stem Cells / Q000378:metabolism*; D009447:Neuroblastoma / Q000378:metabolism*; D010455:Peptides / Q000032:analysis; D015222:Sodium Channels / Q000096:biosynthesis
D000071916:AC133 Antigen; D015703:Antigens, CD; D006023:Glycoproteins; D051036:Large-Conductance Calcium-Activated Potassium Channels; D062556:NAV1.7 Voltage-Gated Sodium Channel; C000606023:PROM1 protein, human; D010455:Peptides; C486866:SCN9A protein, human; D015222:Sodium Channels; D002118:Calcium