Melatonin promotes sorafenib‐induced apoptosis through synergistic activation of <scp>JNK</scp>/c‐jun pathway in human hepatocellular carcinoma

Background/Aims: The aim of our study is to investigate the molecular mechanism by which mammalian STE20-like kinase 1 (Mst1) participates in renal I/R injury through modifying mitophagy and the AMPK-YAP signalling pathway. Methods: WT mice and Mst1-knockout mice were subjected to renal ischaemia-reperfusion (I/R) in vivo. In vitro, the hypoxia-reoxygenation model was used with renal tubular epithelial cells to mimic renal I/R injury. Mitochondrial function was monitored via western blotting and immunofluorescence. Pathway blocker and siRNA knockout technology were used to establish the role of the AMPK-YAP signalling pathway in Mst1-mediated mitochondrial apoptosis in the setting of renal I/R injury. Results: Our data demonstrated that Mst1 expression was upregulated in response to renal I/R injury in vivo, and a higher Mst1 content was positively associated with renal dysfunction and more tubular epithelial cell apoptosis. However, genetic ablation of Mst1 improved renal function, alleviated reperfusion-mediated tubular epithelial cell apoptosis, and attenuated the vulnerability of kidney to I/R injury. In vitro, Mst1 upregulation induced mitochondrial damage including mitochondrial potential reduction, ROS overloading, cyt-c liberation and caspase-9 apoptotic pathway activation. At the molecular levels, I/R-mediated mitochondrial damage via repressing mitophagy and Mst1 suppressed mitophagy via inactivating AMPK signalling pathway and dowregulating OPA1 expression. Re-activation of AMPK-YAP-OPA1 signalling pathway provided a survival advantage for the tubular epithelial cell in the context of renal I/R injury by repressing mitochondrial fission. Conclusion: Overall, our results demonstrate that the pathogenesis of renal I/R injury is closely associated with an increase in Mst1 expression and the inactive AMPK-YAP-OPA1 signalling pathway. Based on this, strategies to repress Mst1 expression and activate mitophagy could serve as therapeutic targets to treat kidney ischaemia-reperfusion injury.

Section: Introductionsupporting

confidence: 70%

Mammalian STE20-Like Kinase 1 Deletion Alleviates Renal Ischaemia-Reperfusion Injury via Modulating Mitophagy and the AMPK-YAP Signalling Pathway

Feng¹,

Li²,

Zhang³

et al. 2018

“…sorafenib in hepatocellular carcinoma [56], cisplatin in hepatocellular carcinoma [57], fluorouracil in oesophageal squamous cell carcinoma [58], etc. Although diverse mechanisms for melatonin-induced apoptosis have been suggested, many of them have the same denominator — ER stress.…”

Section: Discussionmentioning

confidence: 99%

Melatonin-Induced Changes in Cytosolic Calcium Might be Responsible for Apoptosis Induction in Tumour Cells

Chovancova

Hudecová

Lencesova

et al. 2017

Background/Aims: Melatonin is a hormone transferring information about duration of darkness to the organism and is known to modulate several signaling pathways in the cells, e.g. generation of endoplasmic reticulum stress, oxidative status of the cells, etc. Melatonin has been shown to exert antiproliferative and cytotoxic effects on various human cancers. We proposed that this hormone can differently affect tumour cells and healthy cells. Methods: We compared the effect of 24 h melatonin treatment on calcium transport (by fluorescent probes FLUO-3AM and Rhod-5N), ER stress (determined as changes in the expression of CHOP, XBP1 and fluorescently, using Thioflavin T), ROS formation (by CellROX® Green/Orange Reagent) and apoptosis induction (by Annexin-V-FLUOS/propidiumiodide) in two tumour cell lines – ovarian cancer cell line A2780 and stable cell line DLD1 derived from colorectal carcinoma, with non-tumour endothelial cell line EA.hy926. Results: Melatonin increased apoptosis in both tumour cell lines more than twice, while in EA.hy926 cells the apoptosis was increased only by 30%. As determined by silencing with appropriate siRNAs, both, type 1 sodium/calcium exchanger and type 1 IP₃ receptor are involved in the apoptosis induction. Antioxidant properties of melatonin were significantly increased in EA.hy926 cells, while in tumour cell lines this effect was much weaker. Conclusion: Taken together, melatonin has different antioxidative effects on tumour cells compared to non-tumour ones; it also differs in the ability to induce apoptosis through the type 1 sodium/calcium exchanger, and type 1 IP₃ receptor. Different targeting of calcium transport systems in tumour and normal, non-tumour cells is suggested as a key mechanism how melatonin can exert its anticancer effects. Therefore, it might have a potential as a novel therapeutic implication in cancer treatment.

“…Total RNA was extracted from the cells using TRIzol® reagent (Invitrogen Life Technologies, Carlsbad, CA, USA) and was reverse-transcribed into a total of 1 µl (60 ng/µl) cDNA using a One-Step RT-PCR kit (TransGen Biotech Co., Ltd., Beijing, China), according to the manufacturer’s instructions [35]. Quantification of gene expression was performed using an ABI PRISM 7500 Sequence Detection system (Applied Biosystems Life Technologies, Foster City, CA) with SYBR® Green (TransGen Biotech Co., Ltd.) as previously described [33].…”

Section: Methodsmentioning

confidence: 99%

YAP Inhibits the Apoptosis and Migration of Human Rectal Cancer Cells via Suppression of JNK-Drp1-Mitochondrial Fission-HtrA2/Omi Pathways

Zhao

et al. 2017

Background/Aims: The Hippo-Yap pathway is associated with tumor development and progression. However, little evidence is available concerning its role in cancer cell apoptosis and migration via mitochondrial homeostasis. Here, we identify mitochondrial fission as a regulator of the Hippo–Yap pathway in human rectal cancer tumorigenesis and metastasis. Methods: In this study, we performed loss-of function assays concerning Yap in RCC via shRNA. Cellular viability and apoptosis were measured via MTT, the TUNEL assay and trypan blue staining. Mitochondrial function was assessed via JC1 staining, the mPTP opening assay, mitochondrial respiratory function analysis, electron microscopy and immunofluorescence analysis of HtrA2/Omi. Mitophagy and mitochondrial fission were assessed via western blots and immunofluorescence. Cell migration was evaluated via the Transwell assay, wound-healing assay and immunofluorescence analysis of F-actin. The interaction between JNK and Yap was detected via co-immunoprecipitation and Yap recombinant mutagenic plasmid transfection. Western blots were used to analyze signaling pathways in conjunction with JNK inhibitors or HtrA2/Omi siRNA. Results: Yap is upregulated in human rectal cancer cells, where its expression correlates positively with cell survival and migration. Functional studies established that silencing of Yap drove JNK phosphorylation, which induced Drp1 activation and translocation to the surface of mitochondria, initiating mitochondrial fission. Excessive mitochondrial fission mediated HtrA2/Omi leakage from the mitochondria into the cytoplasm, where HtrA2/Omi triggered cellular apoptosis via the mitochondrial apoptosis pathway. Moreover, released HtrA2/Omi also phosphorylated cofilin and inhibited cofilin-mediated F-actin polymerization. F-actin collapse perturbed lamellipodia formation and therefore impaired cellular migration and invasion. Conclusion: Collectively, our results demonstrate that Hippo-Yap can serve as a tumor promoter in human rectal cancer and acts by restricting JNK/Drp1/mitochondrial fission/ HtrA2/Omi, with potential implications for new approaches to human rectal cancer therapy.