Induction of human myeloblastic ML-1 cell G1 arrest by suppression of K+ channel activity

Bo Xu, Brenda A. Wilson, Luo Lu

Research output: Contribution to journalArticlepeer-review


Our previous studies have shown that a voltage-gated K+ channel is highly expressed in proliferating human myeloblastic ML-1 cells and is suppressed in the early stages of 12-O-tetradecanoylphorbol-13-acetate- induced ML-1 cell differentiation. In the present study, we report that inhibition of the K+ channel activity by 4-aminopyridine (4-AP) suppressed ML-1 cell proliferation, as measured by DNA synthesis. Cell cycle mapping indicated that ML-1 cells were arrested in G1 phase after 24-h treatment with 4-AP. Blockade of ML-1 cells at the G1/S boundary of the cell cycle with aphidicolin revealed that ML-1 cells past the G1 checkpoint were capable of entering S phase and synthesizing DNA independently of the channel blockade. ML-1 cell differentiation, measured by CD14 marker protein expression, revealed that the effect of 4-AP was to cause growth arrest and that it did not cause differentiation. Dephosphorylation of retinoblastoma protein accompanied inhibition of ML-1 cell proliferation and suggested that suppression of K+ channel activity by 4-AP is associated with retinoblastoma protein-mediated G1 arrest in ML-1 cells. Moreover, we found that ML-1 cell volume increased 35 ± 7% after 4-AP treatment, which could be an early event triggering inhibition of ML-1 cell proliferation. These findings suggest that a 4-AP-sensitive K+ channel may play an important role in the transduction of mitogenic signals in ML-1 cells.

Original languageEnglish (US)
Pages (from-to)C2037-C2044
JournalAmerican Journal of Physiology - Cell Physiology
Issue number6 40-6
StatePublished - Dec 1996
Externally publishedYes


  • cell cycle
  • mitogenic signals
  • retinoblastoma protein

ASJC Scopus subject areas

  • Physiology
  • Cell Biology


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