BMAL1 Knockdown Leans Epithelial–Mesenchymal Balance toward Epithelial Properties and Decreases the Chemoresistance of Colon Carcinoma Cells

Abstract

The circadian clock coordinates biological and physiological functions to day/night cycles. The perturbation of the circadian clock increases cancer risk and affects cancer progression. Here, we studied how BMAL1 knockdown (BMAL1-KD) by shRNA affects the epithelial–mesenchymal transition (EMT), a critical early event in the invasion and metastasis of colorectal carcinoma (CRC). In corresponding to a gene set enrichment analysis, which showed a significant enrichment of EMT and invasive signatures in BMAL1_high CRC patients as compared to BMAL1_low CRC patients, our results revealed that BMAL1 is implicated in keeping the epithelial–mesenchymal equilibrium of CRC cells and influences their capacity of adhesion, migration, invasion, and chemoresistance. Firstly, BMAL1-KD increased the expression of epithelial markers (E-cadherin, CK-20, and EpCAM) but decreased the expression of Twist and mesenchymal markers (N-cadherin and vimentin) in CRC cell lines. Finally, the molecular alterations after BMAL1-KD promoted mesenchymal-to-epithelial transition-like changes mostly appeared in two primary CRC cell lines (i.e., HCT116 and SW480) compared to the metastatic cell line SW620. As a consequence, migration/invasion and drug resistance capacities decreased in HCT116 and SW480 BMAL1-KD cells. Together, BMAL1-KD alerts the delicate equilibrium between epithelial and mesenchymal properties of CRC cell lines, which revealed the crucial role of BMAL1 in EMT-related CRC metastasis and chemoresistance.

IL-15 Prevents Renal Fibrosis by Inhibiting Collagen Synthesis: A New Pathway in Chronic Kidney Disease?

“…Primary myofibroblast cultures were treated in vitro with IL-15, IL-15/IL-15Rα complex, and/or TGF-β for 48 h in the presence of monensin (2.0 mM; Thermo Fisher Scientific, Illkirch, France, #00-4505) for the last 18 h. Cells were detached with Accutase (Sigma-Aldrich, St. Quentin Fallavier, France, A6964), and intracellular expression of MCP-1 and fibronectin was assessed by flow cytometry as previously described [ 63 ]. Briefly, after fixation and permeabilization using cytofix/cytoperm solution (BD Biosciences, Franklin Lakes, NY, USA), cells were stained with antibodies against MCP-1 (Thermo Fisher Scientific, Illkirch, France, #MA5-17040) or fibronectin (Abcam, Cambridge, UK, Ab2413) for 45 min in the dark at 4 °C, washed with 1× Perm/Wash solution, and labeled with a phycoerythrin (PE)-conjugated secondary antibody for 45 min in the dark at 4 °C.…”

Overcoming therapeutic resistance to platinum-based drugs by targeting Epithelial–Mesenchymal transition

“…It has been found that in nonsmall cell lung cancer (NSCLC), PBDs can increase intracellular Bcell CLL/lymphoma 9 (BCL9) expression and form the b-catenin/ BCL9 complex by selectively binding to the N-terminal structural domain of b-catenin. This binding enhances the transcriptional activity of Wnt signaling and promotes the transcription of bcatenin, thus increasing nuclear translocation and inducing EMT (42). It has also been shown that overexpression of BMAL1 (the central positive loop element that initiates circadian oscillations) and the PDZ-binding motif (TAZ) can induce the EMT by promoting nuclear expression of b-catenin in chemo-resistant colorectal cancer (CRC) cells (38,43).…”

The Relevance of Circadian Clocks to Stem Cell Differentiation and Cancer Progression

“…( F ) CSCs also result from M-cells through dedifferentiation of E-cells during EMT, which is reversed by MET. Studies have shown control of EMT by core circadian clock genes [ 39 – 41 ]. Circadian clocks in cancel cells control EMT events in glioma and breast cancer cells [ 42 ].…”