Circ-Smad5 retards the G1/S transition of cell cycle via inhibiting the activity of wnt/lef/cyclind1 signaling in JB6 cells

Abstract

Circular RNAs are a large class of noncoding RNAs. Smad5 functions in cell differentiation, cell proliferation and metastasis. It has been reported that lnc-Smad5 can inhibit the proliferation of diffuse large B cell lymphoma. However, the function of circ-Smad5 has not yet been reported. Lentivirus vectors were constructed to establish circ-Smad5 upregulated and circ-Smad5 downregulated cell models. A CCK-8 assay was used to detect the proliferation of JB6 cells. FACS was used to analyze the cell cycle in the cell models. Western blot, immunofluorescence staining and TOP/FOP flash dual luciferase activity assays were used to determine the activity of the Wnt signaling pathway. The results revealed that the expression level of circ-Smad5 in JB6 cells was significantly lower than the expression level of linearized-Smad5. Compared with the control group, the percentage of S phase cells and the expression level of cyclin D1 protein were significantly higher in the sh-circ-Smad5 group. In the sh-circ-Smad5 group, β-catenin and LEF-1 were significantly increased, p-β-catenin was significantly decreased, and the relative activity of the TOP/FOP reporter gene was higher compared to the control group levels. These phenomena could be reversed by treating with Wnt signaling inhibitor PNU-74654. We conclude that the circ-Smad5 retards the proliferation and the cell cycle progression of JB6 cells. Thus, circ-Smad5 may function by inhibiting the activation of Wnt/β-catenin/Lef 1 signaling, which inhibits the expression of cyclin D1. To the best of our knowledge, we are the first to report the function of circ-Smad5.

Brusatol enhances MEF2A expression to inhibit RCC progression through the Wnt signalling pathway in renal cell carcinoma

“…Bax, Bcl-2 and Caspase-3 were essential proteins for apoptosis, while CyclinD1 is crucial for the cell cycle's G1 to S phase transition. [40][41][42] Our western blot assay revealed that apoptosis-associated proteins and cyclin D1 were consistent with the flow cytometry results. Therefore, we concluded that MEF2A affects RCC progression by influencing G1/S transition of cell cycle and cell apoptosis.…”

“…Through flow cytometry, we found that overexpression of MEF2A increased the cell number in the G1 phase and the cell apoptosis rate. Bax, Bcl‐2 and Caspase‐3 were essential proteins for apoptosis, while CyclinD1 is crucial for the cell cycle's G1 to S phase transition 40–42 . Our western blot assay revealed that apoptosis‐associated proteins and cyclin D1 were consistent with the flow cytometry results.…”

Twist1 Contributes to the Maintenance of Some Biological Properties of Dermal Papilla Cells in vitro by Forming a Complex With Tcf4 and β-Catenin

“…In the process of tissue development and differentiation, Tcf4 responds to the β-catenin signal and initiates the downstream Wnt signaling pathway, thus promoting cell proliferation and differentiation ( Cadigan, 2012 ). Disruption of Tcf4 or β-catenin can block the Wnt signaling pathway and lead to complete loss of cell proliferation ( Ma et al, 2020 ). Our previous studies have shown that Tcf4 was highly expressed in growing hair follicles and in DPCs cultured in vitro when its morphological features were still in the agglutinative growth mode ( Xiong et al, 2014 ).…”