Attenuation of MUC4 potentiates the anticancer activity of auranofin via regulation of the Her2/Akt/FOXO3 pathway in ovarian cancer cells

Abstract

Previously, we reported that auranofin induces apoptosis in SKOV3 cells via regulation of the IKKβ/FOXO3 pathway. In the present study, we reveal that the anticancer activity of auranofin in SKOV3 cells could be enhanced by the attenuation of MUC4 through the regulation of the Her2/Akt/FOXO3 pathway. Compared to the control-siRNA, siRNA transfection against MUC4 into SKOV3 cells accelerated the protein degradation of Her2. Under the same conditions, the expression level of phosphorylated Akt was also downregulated leading to an increase of FOXO3 in the nucleus. Notably, auranofin treatment in SKOV3 cells also resulted in the downregulation of the expression levels of both Her2 and phosphorylated Akt. Thus, Her2 was identified as the common molecular target protein by siRNA transfection against MUC4. Western blot analysis of total and nuclear fraction lysates from SKOV3 cells revealed that attenuation of MUC4 combined with auranofin treatment in SKOV3 cells synergistically activated FOXO3 translocation from the cytoplasm to the nucleus through the regulation of the Her2/Akt/FOXO3 pathway. Attenuation of MUC4 by siRNA transfection potentiated the antitumor effect of auranofin which was examined by performing in vitro assays such as WST-1, cell counting, colony formation, TUNEL and Annexin V staining. In addition, western blot analysis of the apoptosis‑related proteins such as PARP1, caspase-3, Bim extra large (EL), Bax and Bcl2 revealed that the attenuation of MUC4 by siRNA transfection potentiates the pro-apoptotic activity of auranofin in SKOV3 cells. Collectively, auranofin could regulate the Her2/Akt/FOXO3 signaling pathway in SKOV3 cells and be used as a potential antitumor agent considering the expression of MUC4 in ovarian cancer patients.

Alpha-Fetoprotein Binding Mucin and Scavenger Receptors: An Available Bio-Target for Treating Cancer

“…Additionally, MUC4 has been shown to reduce the interactions between cells, promote cell separation, and promote tumor metastasis (30,50). AFPR was reported to phosphorylate a 185-kDa ErbB2 protein (30), while MUC4 can bind to 185-kDa ErbB2 and induce phosphorylation of ErbB2 at the 1139Y and 1248Y sites, which results in activity of AKT and its related signaling pathways leading to promotion of cell survival (30,(80)(81)(82). MUC4 is highly expressed in breast cancer, and AFPRs were first isolated from the human MCF-7 breast cancer cell line (30).…”

“…Both receptor proteins are highly glycosylated with multiple O-linked glycans. Therefore, MUC4 may also be a viable candidate for an AFP receptor ( 9 , 30 , 82 , 83 ).…”

TAM-derived extracellular vesicles containing microRNA-29a-3p explain the deterioration of ovarian cancer

“…FOXO3 is known as a tumor-inhibitive transcriptional factor and interacts with serine/threonine protein kinase (AKT) in OC. 11 Shen et al. asserted the notion that miR-29a contributes to the drug resistance observed in breast cancer cells through the AKT/glycogen synthase kinase 3β (GSK3β) pathway.…”

Mitoxantrone induces apoptosis in osteosarcoma cells through regulation of the Akt/FOXO3 pathway

“…They indicated that the phosphorylation of Ser318 by Akt induces the subsequent phosphorylation of Ser322 by casein kinase 1, which is critical for translocation of FOXO3 from the nucleus into the cytosol. In previous studies ( 11 , 12 , 23 ), attempts were made to develop a novel cell-based ELISA assay system using a phospho-FOXO3 antibody to screen small molecules causing nuclear localization of FOXO3. Following testing various commercially available phospho-FOXO3 antibodies including pThr32 and pSer253, which are possible Akt-phosphorylation sites identified by Brunet et al ( 10 ), pSer318/321 FOXO3 antibody was selected as the best antibody for the cell-based ELISA system, due to a larger difference in the readout value being detected between the positive controls (Wortmannin and LY294002) and the negative control.…”