FAT4 activation inhibits epithelial-mesenchymal transition (EMT) by promoting autophagy in H2228/Cer cells

Network pharmacology and in vitro experiments based strategy to explore the effects of Jujuboside A on the proliferation and migration ability of glioma cells

OBJECTIVE

This study predicted and verified the effects of Jujuboside A (JuA) on the proliferation and migration ability of glioma cells to developing new therapies for glioma treatment.

METHODS

The druggability of JuA was determined by using cheminformatics. Network pharmacology was used to analyse common targets, biological function and metabolic pathways of JuA against glioma. The core targets of JuA against glioma were validated by using molecular docking. The biological functions of JuA were verified by in vitro experiments.

RESULTS

Cheminformatics results showed that JuA is possible to be a drug. Network pharmacology revealed 294 shared targets between JuA and glioma, which were associated with proliferation, migration, and multiple signalling pathways. A total of 16 core targets related to the signalling pathways were verified by molecular docking. The in vitro experiments showed that JuA could inhibit cell proliferation and migration, decrease cell numbers and alter cell morphology.

CONCLUSION

The results of network pharmacology and in vitro experiments indicate that JuA has significant toxic effects on glioma cells, and can play a therapeutic role in treating glioma by inhibiting the proliferation and migration of glioma cells.

EML4-ALK G1202R and EML4-ALK L1196M mutations induce crizotinib resistance in non-small cell lung cancer cells through activating epithelial-mesenchymal transition mediated by MDM2/MEK/ERK signal axis

Crizotinib, as the first-generation of anaplastic lymphoma kinase (ALK) inhibitor, effectively improves the survival time of ALK-positive non-small cell lung cancer (NSCLC) patients. However, its efficacy is severely limited by drug resistance caused by secondary mutations. G1202R and L1196M are classical mutation sites located in ALK kinase domain. They may hinder the binding of ALK inhibitors to the target kinase domain, resulting in drug resistance in patients. However, the exact mechanism of drug resistance mediated by these mutations remains unclear. In this study, we aimed to evaluate how G1202R and L1196M mutations mediate crizotinib resistance. To explore the resistance mechanism, we constructed EML4-ALK G1202R and L1196M mutant cell lines with A549 cells. The results showed that the mutant cells exhibited significant epithelial-mesenchymal transition (EMT) and metastasis compared to control (A549-vector) or wild type (A549-EML4-ALK) cells. Subsequently, it was found that the occurrence of EMT was correlated to the high expression of murine double minute 2 (MDM2) protein and the activation of mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway in mutant cells. Down-regulation of MDM2 inhibited the activation of MEK/ERK pathway, thus reversed the EMT process and markedly increased the inhibitory effect of crizotinib on the growth of mutant cells. Collectively, resistance of ALK-positive NSCLC cells to crizotinib is induced by G1202R and L1196M mutations through activation of the MDM2/MEK/ERK signalling axis, promoting EMT process and metastasis. These findings suggest that the combination of MDM2 inhibitors and crizotinib could be a potential therapeutic strategy.

Early short-term hypoxia promotes epidermal cell migration by activating the CCL2-ERK1/2 pathway and epithelial-mesenchymal transition during wound healing

Background

Due to vasculature injury and increased oxygen consumption, the early wound microenvironment is typically in a hypoxic state. We observed enhanced cell migration ability under early short-term hypoxia. CCL2 belongs to the CC chemokine family and was found to be increased in early hypoxic wounds and enriched in the extracellular signal-regulated kinase (ERK)1/2 pathway in our previous study. However, the underlying mechanism through which the CCL2-ERK1/2 pathway regulates wound healing under early short-term hypoxia remains unclear. Activation of epithelial-mesenchymal transition (EMT) is a key process in cancer cell metastasis, during which epithelial cells acquire the characteristics of mesenchymal cells and enhance cell motility and migration ability. However, the relationship between epithelial cell migration and EMT under early short-term hypoxia has yet to be explored.

Methods

HaCaT cells were cultured to verify the effect of early short-term hypoxia on migration through cell scratch assays. Lentiviruses with silenced or overexpressed CCL2 were used to explore the relationship between CCL2 and migration under short-term hypoxia. An acute full-thickness cutaneous wound rat model was established with the application of an ERK inhibitor to reveal the hidden role of the ERK1/2 pathway in the early stage of wound healing. The EMT process was verified in all the above experiments through western blotting.

Results

In our study, we found that short-term hypoxia promoted cell migration. Mechanistically, hypoxia promoted cell migration through mediating CCL2. Overexpression of CCL2 via lentivirus promoted cell migration, while silencing CCL2 via lentivirus inhibited cell migration and the production of related downstream proteins. In addition, we found that CCL2 was enriched in the ERK1/2 pathway, and the application of an ERK inhibitor in vivo and in vitro verified the upstream and downstream relationships between the CCL2 pathway and ERK1/2. Western blot results both in vivo and in vitro demonstrated that early short-term hypoxia promotes epidermal cell migration by activating the CCL2-ERK1/2 pathway and EMT during wound healing.

Conclusions

Our work demonstrated that hypoxia in the early stage serves as a stimulus for triggering wound healing through activating the CCL2-ERK1/2 pathway and EMT, which promote epidermal cell migration and accelerate wound closure. These findings provide additional detailed insights into the mechanism of wound healing and new targets for clinical treatment.

Contribution of Autophagy to Epithelial Mesenchymal Transition Induction during Cancer Progression

Epithelial Mesenchymal Transition (EMT) is a dedifferentiation process implicated in many physio-pathological conditions including tumor transformation. EMT is regulated by several extracellular mediators and under certain conditions it can be reversible. Autophagy is a conserved catabolic process in which intracellular components such as protein/DNA aggregates and abnormal organelles are degraded in specific lysosomes. In cancer, autophagy plays a controversial role, acting in different conditions as both a tumor suppressor and a tumor-promoting mechanism. Experimental evidence shows that deep interrelations exist between EMT and autophagy-related pathways. Although this interplay has already been analyzed in previous studies, understanding mechanisms and the translational implications of autophagy/EMT need further study. The role of autophagy in EMT is not limited to morphological changes, but activation of autophagy could be important to DNA repair/damage system, cell adhesion molecules, and cell proliferation and differentiation processes. Based on this, both autophagy and EMT and related pathways are now considered as targets for cancer therapy. In this review article, the contribution of autophagy to EMT and progression of cancer is discussed. This article also describes the multiple connections between EMT and autophagy and their implication in cancer treatment.

Nanoplatform-Mediated Autophagy Regulation and Combined Anti-Tumor Therapy for Resistant Tumors

The overall cancer incidence and death toll have been increasing worldwide. However, the conventional therapies have some obvious limitations, such as non-specific targeting, systemic toxic effects, especially the multidrug resistance (MDR) of tumors, in which, autophagy plays a vital role. Therefore, there is an urgent need for new treatments to reduce adverse reactions, improve the treatment efficacy and expand their therapeutic indications more effectively and accurately. Combination therapy based on autophagy regulators is a very feasible and important method to overcome tumor resistance and sensitize anti-tumor drugs. However, the less improved efficacy, more systemic toxicity and other problems limit its clinical application. Nanotechnology provides a good way to overcome this limitation. Co-delivery of autophagy regulators combined with anti-tumor drugs through nanoplatforms provides a good therapeutic strategy for the treatment of tumors, especially drug-resistant tumors. Notably, the nanomaterials with autophagy regulatory properties have broad therapeutic prospects as carrier platforms, especially in adjuvant therapy. However, further research is still necessary to overcome the difficulties such as the safety, biocompatibility, and side effects of nanomedicine. In addition, clinical research is also indispensable to confirm its application in tumor treatment.

Metformin rescues migratory deficits of cells derived from patients with periventricular heterotopia

Periventricular neuronal heterotopia (PH) is one of the most common forms of cortical malformation in the human cortex. We show that human neuronal progenitor cells (hNPCs) derived from PH patients with a DCHS1 or FAT4 mutation as well as isogenic lines had altered migratory dynamics when grafted in the mouse brain. The affected migration was linked to altered autophagy as observed in vivo with an electron microscopic analysis of grafted hNPCs, a Western blot analysis of cortical organoids, and time-lapse imaging of hNPCs in the presence of bafilomycin A1. We further show that deficits in autophagy resulted in the accumulation of paxillin, a focal adhesion protein involved in cell migration. Strikingly, a single-cell RNA-seq analysis of hNPCs revealed similar expression levels of autophagy-related genes. Bolstering AMPK-dependent autophagy by metformin, an FDA-approved drug, promoted migration of PH patients-derived hNPCs. Our data indicate that transcription-independent homeostatic modifications in autophagy contributed to the defective migratory behavior of hNPCs in vivo and suggest that modulating autophagy in hNPCs might rescue neuronal migration deficits in some forms of PH.