Cucurbitacin B inhibits TGF-β1-induced epithelial–mesenchymal transition (EMT) in NSCLC through regulating ROS and PI3K/Akt/mTOR pathways

Abstract

Background Lung cancer is the leading cause of cancer mortality worldwide, and most of the patients after treatment with EGF-TKIs develop drug resistance, which is closely correlated with EMT. Cucurbitacin B (CuB) is a natural product of the Chinese herb Cucurbitaceae plant, which has a favorable role in anti-inflammation and anti-cancer activities. However, the effect of CuB on EMT is still far from fully explored. In this study, the inhibition effect of CuB on EMT was investigated. Methods In this study, TGF-β1 was used to induce EMT in A549 cells. MTS assay was used to detect the cell viability of CuB co-treated with TGF-β1. Wound healing assay and transwell assay were used to determine the migration and invasion capacity of cells. Flow cytometry and fluorescence microscope were used to detect the ROS level in cells. Western blotting assay and immunofluorescence assay were used to detect the proteins expression. Gefitinib was used to establish EGF-TKI resistant NSCLC cells. B16-F10 intravenous injection mice model was used to evaluate the effect of CuB on lung cancer metastasis in vivo. Caliper IVIS Lumina and HE staining were used to detect the lung cancer metastasis of mice. Results In this study, the results indicated that CuB inhibited TGF-β1-induced EMT in A549 cells through reversing the cell morphology changes of EMT, increasing the protein expression of E-cadherin, decreasing the proteins expression of N-cadherin and Vimentin, suppressing the migration and invasion ability. CuB also decreased the ROS production and p-PI3K, p-Akt and p-mTOR expression in TGF-β1-induced EMT in A549 cells. Furthermore, Gefitinib resistant A549 cells (A549-GR) were well established, which has the EMT characteristics, and CuB could inhibit the EMT in A549-GR cells through ROS and PI3K/Akt/mTOR pathways. In vivo study showed that CuB inhibited the lung cancer metastasis effectively through intratracheal administration. Conclusion CuB inhibits EMT in TGF-β1-induced A549 cells and Gefitinib resistant A549 cells through decreasing ROS production and PI3K/Akt/mTOR signaling pathway. In vivo study validated that CuB inhibits lung cancer metastasis in mice. The study may be supporting CuB as a promising therapeutic agent for NSCLC and Gefitinib resistant NSCLC.

A Systematic Review of Progress toward Unlocking the Power of Epigenetics in NSCLC: Latest Updates and Perspectives

“…Liu et al demonstrated that CuB regulated cell proliferation and apoptosis by suppressing the XIST/miR-let-7c/IL-6/STAT3 axis in NSCLC [ 132 ]. Similarly, Yu et al showed that CuB reduced the proliferation of gefitinib-resistant PC9 cells by modulating the miR-175p/STAT3 axis [ 133 ], while Yuan et al highlighted the inhibition of epithelial–mesenchymal transition (EMT) in TGF-β1 -induced A549 cells and gefitinib-resistant A549 cells via a decrease in ROS production and disruption of the PI3K/Akt/mTOR signaling pathway [ 134 ]. Furthermore, Liu et al found that CuB suppressed the growth and invasion of gefitinib-resistant NSCLC cells by inducing lysosomal EGFR degradation and by downregulating the CIP2A/PP2A/Akt signaling axis [ 135 ].…”

UCP2 promotes NSCLC proliferation and glycolysis via the mTOR/HIF‐1α signaling

“…24,25 Inhibiting mTOR signaling pathway could suppress EMT in NSCLC cells, supporting mTOR as a promising treatment focus for NSCLC. 26 Recently, a variety of targeted inhibitors against mTOR are under a series of clinical trials in NSCLC. 27 It is reported that through the AKT/mTOR signaling, UCP2 could associate with DDX5 to regulate the metabolic plasticity in NSCLC.…”

Unveiling the role of cellular dormancy in cancer progression and recurrence

“…Activation of the MAPK p38, a common characteristic of DTPs, is indeed redox-dependent and it operates upstream of two vital mediators of cancer dormancy, namely NR2F1 and p53 [62][63][64]. Reactive oxygen species (ROS) can also influence, directly or indirectly, a number of signaling pathways involved in cancer dormancy, including TGF-b, SHH, Wnt, mTOR and autophagy [63,65,66]. In conclusion, the TME serves various functions that support local dormant niches and plays a crucial role in balancing cellular dormancy and reactivation of proliferation.…”