Overexpression of DUSP6 enhances chemotherapy-resistance of ovarian epithelial cancer by regulating the ERK signaling pathway

Abstract

Objective: DUSP6 is a negative regulator of the ERK signaling pathway and plays an important role in chemotherapy-resistance. Previously we showed that DUSP6 is overexpressed in ovarian cancer side population (SP) cells that possess cancer stem cell-like properties and are quiescent and chemotherapy-resistant. Here, we explore the effects of DUSP6 on chemotherapy-resistance by examining its regulation of the ERK signaling pathway and G0/G1 cell cycle arrest. Methods: mRNA and protein expression of DUSP6 and G0/G1 cell cycle checkpoint regulating proteins (CyclinD1, CyclinD3 and CyclinE2) was evaluated among ovarian cancer cell lines and tissue samples. Ovarian cancer cells were transiently transfected to overexpress DUSP6. After treatment with cisplatin, cell viability was measured by the MTS assay at 48 hours and the half maximal inhibitory concentration (IC50) for each cell line was calculated. Subcellular localization and cell cycle analysis were determined by using immunofluorescence and FACS, respectively. Results: SKOV3 and OVCAR8 SP cells were shown to express higher levels of DUSP6 and lower levels of CyclinD3 compared with non-SP (NSP) cells (P<0.001). Among 39 ovarian cancer tissue samples, expression of DUSP6 in the chemotherapy-resistant group (12 samples) was higher than in the chemotherapy-sensitive group (27 samples) (P<0.05). While a lower level of expression of CyclinD3 was seen in the chemotherapy-resistant group, it was not statistically different from the chemotherapy-sensitive group. HO8910 cells where shown to have higher IC50 to cisplatin than SKOV3 or OVCAR8 cells, and this correlated with higher levels of DUSP6 expression. Overexpression of DUSP6 in SKOV3 cells led to an increase in cisplatin IC50 values (P<0.05), and also markedly reduced the expression levels of phospho-ERK1/2 and CyclinD3 and to the predominance of cells in the G0/G1 phase. Conclusion: Our findings reveal an enhancement of chemotherapy-resistance and a predominance of cells in G1 cell cycle arrest in DUSP6-overexpressing ovarian cancer cells. This suggests that overexpression of DUSP6 promotes chemotherapy-resistance through the negative regulation of the ERK signaling pathway, increasing the G0/G1 phase ratio among ovarian cancer cells, and leading to cellular quiescence.

<i>LIN28A</i> inhibits <i>DUSP</i> family phosphatases and activates MAPK signaling pathway to maintain pluripotency in porcine induced pluripotent stem cells

“…The mRNA expression levels of DUSP6/8/10 were markedly up-regulated after LIN28A knockdown. As a member of the DUSP family, DUSP6/8/10 inhibits ERK activity to regulate MAPK signaling in ovarian epithelial cancer ( Gao et al, 2020 ), pancreatic cancer ( Liu et al, 2021 ), and human epidermal stem cells ( Hiratsuka et al, 2020 ). The increase in DUSP6/8/10 expression indicates inactivation of MAPK signaling ( Cornacchia et al, 2019 ).…”

m6A methyltransferase Wilms' tumor 1‐associated protein facilitates cell proliferation and cisplatin resistance in NK/T cell lymphoma by regulating dual‐specificity phosphatases 6 expression via m6A RNA methylation

“…23 Several reports have revealed that DUSP6 is closely associated with chemotherapy resistance in a variety of cancers. [24][25][26] Because WTAP is the core catalytic component in the RNA m6A methyltransferase complex, we considered that m6A methylation contribute to dysregulation of DUSP6. Herein, we observed that DUSP6 was depleted by WTAP elimination and modified by WTAP-mediated m6A methylation as detected by MeRIP-qPCR.…”

“…It has been demonstrated that DUSP6 is involved in various physiological and pathological processes in diverse malignancies 23 . Several reports have revealed that DUSP6 is closely associated with chemotherapy resistance in a variety of cancers 24–26 . Because WTAP is the core catalytic component in the RNA m6A methyltransferase complex, we considered that m6A methylation contribute to dysregulation of DUSP6.…”

Anti-tumor effect of Huaier extract against neuroblastoma cells in vitro

“…Given that treatment with Huaier extract downregulated the expression of cyclinD3 (Fig. 2B), which is one of the downstream factors of ERK [17], we attempted to determine the changes of MEK/ERK related protein expression after Huaier extract treatment in NB cells. By treating the 3 NB cell lines with different concentrations of Huaier extract, the phosphorylation of MEK and ERK was significantly inhibited in dose-dependent manner (Fig.…”