Stathmin dynamics modulate the activity of eribulin in breast cancer cells

Abstract

Stathmin, a phosphoprotein that modulates microtubule dynamics, is highly expressed in breast cancer cells. Eribulin, a microtubule‐depolymerizing agent, is used to treat patients with advanced breast cancer. However, the detailed mechanisms underlying the action of eribulin during microtubule catastrophe, and the interaction between eribulin and stathmin dynamics, remain unclear. Here, we investigated the role of stathmin in the antiproliferative activity of eribulin in breast cancer cells. Eribulin induced phosphorylation of stathmin in MCF7 and MDA‐MB‐231 cells; this was attenuated by an inhibitor of protein kinase A (H89) and an inhibitor of Ca 2+ /calmodulin‐dependent kinase II (KN62). In addition, expression of phosphorylated stathmin was reduced by the protein phosphatase PP2A activator FTY720 but increased by the PP2A inhibitor okadaic acid. Of note, expression of PP2A subunits in eribulin‐treated cells decreased, although eribulin did not affect the phosphatase activity of recombinant PP2A directly. Furthermore, the antiproliferative effect of eribulin was stronger in stathmin‐overexpressing cells. These results suggest that stathmin dynamics are closely associated with the antiproliferative effects of eribulin and stathmin is a possible biomarker for predicting the therapeutic effects of eribulin in breast cancer patients.

PGRMC1 Regulates Cellular Senescence via Modulating FOXO1 Expression in Decidualizing Endometrial Stromal Cells

“…ESCs grown to 50% confluency in 24-well plates were transfected with non-targeting control siRNA (30 pmol; Qiagen, Mississauga, ON, Canada), PGRMC1 siRNA (30 pmol; EHU003641, Sigma-Aldrich) or FOXO1 siRNA (30 pmol, Sigma-Aldrich), using Lipofectamine RNAiMAX Transfection Reagent (Invitrogen, Carlsbad, CA, USA) according to the manufacturer’s instructions [ 28 ]. After treatment with siRNA, the cells were washed with a phosphate-buffered saline (PBS) and treated with a medium containing or lacking P4 or cAMP analogs for 2 days.…”

“…The membranes were then treated with a stripping solution and re-probed with an antibody against GAPDH (1:10,000). The relative band intensity was evaluated by the densitometric analysis of digitalized autographic images using ImageJ software (NIH, Bethesda, MD, USA) and normalized to that of GAPDH [ 28 ].…”

“…Sense (S) and antisense (AS) primers were 5′-AAGGGTGACAGCAACAGCTC-3′ (S) and 5′-TTCTGCACACGAATGAACTTG-3′ (AS) for PGRMC1, 5′-AAGGGTGACAGCAACAGCTC-3′ (S) and 5′-TTCTGCACACGAATGAACTTG-3′ (AS) for FOXO1, 5′-AGACAGCCACTCACCTCTTCAG-3′ (S) and 5′-TTCTGCCAGTGCCTCTTTGCTG-3′ (AS) for IL6, 5′-AAGACATACTCCAAACCTTTCCA-3′ (S) and 5′-CCAGACAGAGCTCTCTTCCA-3′ (AS) for IL8, 5′-AACAGAAGCCAACTGGGTGAATG-3′ (S) and 5′-CTCCAAGAGAAAGCACTTCATTGC-3′ (AS) for IL15, and 5′-AGCCACATCGCTCAGACA-3′ (S) and 5′-GCCCAATACGACCAAATCC-3′ (AS) for GAPDH. The fold change in the expression of each gene was calculated using the ΔΔCt method with GAPDH as an internal control [ 28 ].…”

The Impact of Eribulin on Stathmin Dynamics and Paclitaxel Sensitivity in Ovarian Cancer Cells

“…Our previous studies demonstrated that eribulin caused phosphorylation of stathmin by not only downregulating PP2A levels but also by activating PKA and CaMKII path- ways in breast cancer cells. 21) By contrast, eribulin-induced phosphorylation of stathmin was not affected by PKA and CaMKII inhibitors in ovarian cancer cells. In addition, paclitaxel enhances stathmin phosphorylation in acute lymphoblastic leukemia cells and increases PP2A expression in non-small cell lung cancer (NSCLC) cells.…”

“…20) Of note, our recent studies showed that the antiproliferative activity of eribulin may be associated with the modulation of stathmin dynamics in breast cancer cells. 21) Although the inhibitory effect of eribulin on ovarian cancer proliferation has been reported, the relationship between the efficacy of eribulin and stathmin dynamics has not been characterized in ovarian cancer. The present study was therefore undertaken to examine the correlation between the antitumor effect of eribulin and stathmin dynamics in human epithelial ovarian cancer cells.…”