Cell Cycle Regulation by Ca2+-Activated K+ (BK) Channels Modulators in SH-SY5Y Neuroblastoma Cells

Abstract

The effects of Ca2+-activated K+ (BK) channel modulation by Paxilline (PAX) (10−7–10−4 M), Iberiotoxin (IbTX) (0.1–1 × 10−6 M) and Resveratrol (RESV) (1–2 × 10−4 M) on cell cycle and proliferation, AKT1pSer473 phosphorylation, cell diameter, and BK currents were investigated in SH-SY5Y cells using Operetta-high-content-Imaging-System, ELISA-assay, impedentiometric counting method and patch-clamp technique, respectively. IbTX (4 × 10−7 M), PAX (5 × 10−5 M) and RESV (10−4 M) caused a maximal decrease of the outward K+ current at +30 mV (Vm) of −38.3 ± 10%, −31.9 ± 9% and −43 ± 8%, respectively, which was not reversible following washout and cell depolarization. After 6h of incubation, the drugs concentration dependently reduced proliferation. A maximal reduction of cell proliferation, respectively of −60 ± 8% for RESV (2 × 10−4 M) (IC50 = 1.50 × 10−4 M), −65 ± 6% for IbTX (10−6 M) (IC50 = 5 × 10−7 M), −97 ± 6% for PAX (1 × 10−4 M) (IC50 = 1.06 × 10−5 M) and AKT1pser473 dephosphorylation was observed. PAX induced a G1/G2 accumulation and contraction of the S-phase, reducing the nuclear area and cell diameter. IbTX induced G1 contraction and G2 accumulation reducing diameter. RESV induced G2 accumulation and S contraction reducing diameter. These drugs share common actions leading to a block of the surface membrane BK channels with cell depolarization and calcium influx, AKT1pser473 dephosphorylation by calcium-dependent phosphatase, accumulation in the G2 phase, and a reduction of diameter and proliferation. In addition, the PAX action against nuclear membrane BK channels potentiates its antiproliferative effects with early apoptosis.

Zoledronic Acid Modulation of TRPV1 Channel Currents in Osteoblast Cell Line and Native Rat and Mouse Bone Marrow-Derived Osteoblasts: Cell Proliferation and Mineralization Effect

“…Also, it was not possible to use specific BK channel blockers, such as Ibtx or paxilline, because of their irreversible blocking action of the BK channel associated with antiproliferative effects [19,34]. Also, it should be noted that other potent and selective TRPV1 antagonist are available; in our experiments, we use capsazepine to block TRPV1 channel because of the its well-known pharmacology and the lack of action on cell proliferation and mineralization.…”

“…Instead, loss of function of the inwardly rectifying K + channel Kir2.1 impairs both osteoblastic and chondrogenic processes, leading to the rare Andersen’s syndrome [18]. Furthermore, we previously demonstrated that large-conductance Ca 2+ -activated K + (BK) channels are involved in cell proliferation, since the incubation of SH-SY5Y cells with BK channel antagonists paxilline, iberiotoxin, and resveratrol was associated with a reduction of cell proliferation, reducing cell diameter and inducing AKT1p ser473 dephosphorylation [19].…”

Role for calcium‐activated potassium channels (BK) in migration control of human hepatocellular carcinoma cells

“…27,28 This finding was also consistent with that by Zhou et al who also observed BK channels expression in HCC cells. 29 Before our research on BK channels in HCC, previous studies reported that BK channels in various cancer cells such as triple-negative breast cancer cells, 18 neuroblastoma cells, 19 human glioblastoma cells 21,22 and human astrocytoma cells. 30 We examined BK channel expression in HCC patients and assessed the association of its expression with overall survival, with data obtained from online TCGA library.…”

Tumour initiation, store-operated calcium entry (SOCE) and apoptosis: cyclic nucleotide dependence

“…The BK Ca channel antagonists paxilline (1), progesterone (2) and genistein (3) fit across the length of the cGMP structure (Figure 4). Paxilline, in common with thapsigargin and cyclopiazonic acid, enhances apoptosis mediated by TRAIL (tumour necrosis factor-related apoptosis-induced ligand) and regulates the cell cycle of neuroblastoma cells (Kang et al 2011;Maqoud et al 2018). Progesterone and genistein induce apoptosis and protect against apoptosis (Table 1); both compounds have the same O6-O8 atomic distance, nucleotide fit and BK Ca channel blocking activity.…”