HSPA4 regulated glioma progression via activation of AKT signaling pathway

Glioma is still an incurable disease with high invasiveness. Heat shock 70 kDa protein 4 (HSPA4) is a member of the HSP110 family, and is associated with the development and progression of various cancers. In the current study, we assessed the expression of HSPA4 in clinical samples, and found that HSPA4 was up-regulated in glioma tissues and correlated with tumor recurrence and grade. Survival analyses demonstrated that glioma patients with high HSPA4 expression had lower overall survival and disease-free survival times. In vitro knockdown of HSPA4 inhibited glioma cell proliferation, mediated cell cycle arrest at G2 phase and apoptosis, and reduced the migration ability. In vivo, the growth of HSPA4-knockdown xenografts was markedly suppressed compared to the tumors formed by HSPA4-positive control cells. Additionally, Gene set enrichment analyses disclosed that HSPA4 was associated with the PI3K/Akt signaling pathway. The regulatory effect of the AKT activator SC79 on cell proliferation and apoptosis was suppressed by HSPA4 knockdown, indicating that HSPA4 is capable of promoting glioma development. In summary, these data showed that HSPA4 is likely to play a pivotal role in the progression of glioma, and consequently may be a promising therapeutic target for glioma therapy.

Structure-based design and synthesis of anti-fibrotic compounds derived from para-positioned 3,4,5-trisubstituted benzene

Liver fibrosis is an abnormal wound-healing response to liver injuries. It can lead to liver cirrhosis, and even liver cancer and liver failure. There is a lack of treatment for liver fibrosis and it is of great importance to develop anti-fibrotic drugs. A pivotal event in the process of developing liver fibrosis is the activation of hepatic stellate cells (HSCs), in which the nuclear receptor Nur77 plays a crucial role. This study aimed to develop novel anti-fibrotic agents with Nur77 as the drug target by modifying the structure of THPN, a Nur77-binding and anti-melanoma compound. Specifically, a series of para-positioned 3,4,5-trisubstituted benzene ring compounds with long-chain backbone were generated and tested for anti-fibrotic activity. Among these compounds, compound A8 was with the most potent and Nur77-dependent inhibitory activity against TGF-β1-induced activation of HSCs. In a crystal structure analysis, compound A8 bound Nur77 in a peg-in-hole mode as THPN did but adopted a different conformation that could interfere the Nur77 interaction with AKT, which was previous shown to be important for an anti-fibrotic activity. In a cell-based assay, compound A8 indeed impeded the interaction between Nur77 and AKT leading to the stabilization of Nur77 without the activation of AKT. In a mouse model, compound A8 effectively suppressed the activation of AKT signaling pathway and up-regulated the cellular level of Nur77 to attenuate the HSCs activation and ameliorate liver fibrosis with no significant toxic side effects. Collectively, this work demonstrated that Nur77-targeting compound A8 is a promising anti-fibrotic drug candidate.

Ovarian Tumor Domain-Containing 7B Attenuates Pathological Cardiac Hypertrophy by Inhibiting Ubiquitination and Degradation of Krüppel-Like Factor 4

BACKGROUND

Cardiac hypertrophy (CH) is a well-established risk factor for many cardiovascular diseases and a primary cause of mortality and morbidity among older adults. Currently, no pharmacological interventions have been specifically tailored to treat CH. OTUD7B (ovarian tumor domain-containing 7B) is a member of the ovarian tumor-related protease (OTU) family that regulates many important cell signaling pathways. However, the role of OTUD7B in the development of CH is unclear. Therefore, we investigated the role of OTUD7B in CH.

METHODS AND RESULTS

OTUD7B knockout mice were used to assay the role of OTUD7B in CH after transverse aortic coarctation surgery. We further assayed the specific functions of OTUD7B in isolated neonatal rat cardiomyocytes. We found that OTUD7B expression decreased in hypertrophic mice hearts and phenylephrine-stimulated neonatal rat cardiomyocytes. Furthermore, OTUD7B deficiency exacerbated transverse aortic coarctation surgery-induced myocardial hypertrophy, abnormal cardiac function, and fibrosis. In cardiac myocytes, OTUD7B knockdown promoted phenylephrine stimulation-induced myocardial hypertrophy, whereas OTUD7B overexpression had the opposite effect. An immunoprecipitation-mass spectrometry analysis showed that OTUD7B directly binds to KLF4 (Krüppel-like factor 4). Additional molecular experiments showed that OTUD7B impedes KLF4 degradation by inhibiting lysine residue at 48 site-linked ubiquitination and suppressing myocardial hypertrophy by activating the serine/threonine kinase pathway.

CONCLUSIONS

These results demonstrate that the OTUD7B-KLF4 axis is a novel molecular target for CH treatment.

PYCR2 promotes growth and aerobic glycolysis in human liver cancer by regulating the AKT signaling pathway

Hepatocellular carcinoma (HCC) is the world's third most fatal cancer. Because metabolic rewiring is a hallmark of HCC, studies into the causes of aberrant glycolysis could provide insight into novel HCC therapeutic strategies. Pyrroline-5-carboxylate reductase 2 (PYCR2), a key enzyme of proline synthesis, has previously been found to play vital roles in various malignancies regarding amino acid metabolism and oxidative stress response. Our study investigated the mechanistic function of PYCR2 in HCC. We used Gene Expression Profiling Interactive Analysis to perform bioinformatics analysis of PYCR2 expression and survival in human HCC patients based on the Cancer Genome Atlas database. The function of PYCR2 in cell viability and glycolysis was assessed using CCK-8 and ECAR assays. Transducing shRNA or overexpression vectors into the HCC cell line altered the expression status of PYCR2. PYCR2 expression was validated using quantitative real-time PCR and Western blot. In mouse xenograft models, the role of PYCR2 in HCC tumor formation was confirmed. PYCR2 was overexpressed in human HCC tumor tissue and was associated with a poor prognosis. The functional assay revealed that silencing PYCR2 inhibited cell viability, glycolysis, and AKT activation. Furthermore, the xenograft experiment demonstrated that silencing PYCR2 significantly inhibited tumor growth and Ki67 expression. On the other hand, PYCR2 overexpression significantly promoted cell viability and glycolysis, which could be inhibited by either a glycolysis inhibitor or an AKT inhibitor, indicating that PYCR2 may function via glycolysis and the AKT pathway. Moreover, despite the overexpression of PYCR2 in vivo, treatment with a glycolysis inhibitor may considerably suppress tumor growth. Our findings suggest that PYCR2 may play an oncogenic role in HCC growth by promoting glycolysis and activating AKT, emphasizing PYCR2's clinical relevance in HCC management as a novel potential therapeutic target.

Oridonin Synergistically Enhances the Pro-Apoptotic Effect of Venetoclax on Acute Myeloid Leukemia Cells by Inhibiting AKT Signaling

BACKGROUND

Acute myeloid leukemia (AML) is a recurrence-prone hematologic malignancy. The advent of molecularly targeted therapies provides new opportunities to enhance the effectiveness of AML treatments. Venetoclax, a selective inhibitor of the anti-apoptotic protein Bcl-2, has shown promising results; however, resistance often arises due to elevated expression of the Mcl-1 protein, among other factors. Overcoming this resistance to improve therapeutic outcomes is a pressing issue that requires further investigation. Studies have demonstrated that oridonin, by inhibiting AKT signaling that regulates Mcl-1 expression, can effectively suppress tumor cell growth. This study aims to investigate whether oridonin can synergistically enhance the anti-leukemic effects of venetoclax and explore the underlying mechanisms behind this effect.

METHODS

In vitro experiments were performed to evaluate the effects of the combination of oridonin and venetoclax on AML cell proliferation, apoptosis, cell cycle distribution, and mitochondrial membrane potential. Transcriptome sequencing was used to elucidate the molecular mechanisms underlying the synergistic induction of AML cell apoptosis by the combination therapy. Western blotting and reverse transcription quantitative polymerase chain reaction (RT-qPCR) techniques were used to validate the findings. Additionally, an AML mouse model was established to observe the synergistic anti-AML effects of venetoclax combined with oridonin in vivo.

RESULTS

Both venetoclax and oridonin individually exhibited inhibitory effects on AML cell proliferation, resulted in cell cycle arrest, and induced cell apoptosis. Moreover, combination of the two drugs resulted in a synergistic effect. We also observed that oridonin inhibited AKT phosphorylation, upregulated the expression of Bim and Bax proteins, facilitated Mcl-1 degradation, and enhanced the apoptotic effects of venetoclax in AML cells. Finally, in vivo experiments demonstrated that the combination of oridonin and venetoclax effectively inhibited the growth of AML xenograft tumors in mice and prolonged the survival time of tumor-bearing mice.

CONCLUSIONS

Oridonin and venetoclax synergistically promote AML cell apoptosis by inhibiting AKT signaling.

circACTR2 attenuates gemcitabine chemoresiatance in pancreatic cancer through PTEN mediated PI3K/AKT signaling pathway

BACKGROUND

Recently, accumulating studies have unveiled that circRNAs exert critical function in a variety of tumor biological processes including chemoresistance. Our previous study has found circACTR2 is significantly down-regulated in acquired gemcitabine (GEM)- resistant pancreatic cancer (PC) cells, which has not been well-explored. Our study aimed to research the function and molecular mechanism of circACTR2 in PC chemoresistance.

METHODS

qRT-PCR and western blot analysis was performed to detect gene expression. The effect of circACTR2 on PC GEM resistance were examined by CCK-8 and flow cytometry assays. Whether circACTR2 could sponge miR-221-3p and regulate PTEN expression were determined by bioinformatics analysis, RNA pull-down, and Dual-luciferase reporter assay.

RESULTS

circACTR2 was notably down-regulated in a panel of GEM-resistant PC cells lines, and negatively associated with aggressive phenotype and poor prognosis of PC. circACTR2 downregulation contributed to GEM chemoresistance of PC cells with decreased S phase ratio of cell cycle and cell apoptosis, as confirmed by gain- and loss-of-function assays in vitro. In addition, circACTR2 overexpression retarded GEM resistance in vivo. Further, circACTR2 acted as a ceRNA against miR-221-3p, which directly targeted PTEN. The mechanistic studies revealed that loss of circACTR2 promoted GEM resistance in PC through activating the PI3K/AKT signaling pathway by downregulating PTEN expression in a miR-221-3p dependent manner.

CONCLUSIONS

circACTR2 reversed the chemoresistance of PC cells to GEM through inhibiting PI3K/AKT signaling pathway by sponging miR-221-3p and upregulating PTEN expression.

Gli1 promotes the phenotypic transformation of valve interstitial cells through Hedgehog pathway activation exacerbating calcific aortic valve disease

Calcific aortic valve disease (CAVD) is the most prevalent human valve disease worldwide. Multiple factors induce "irreversible" pathological changes in the aortic valve leaflets, resulting in changes in cardiac hemodynamics, eventually leading to heart failure. However, no effective pharmaceutical interventions have been found and prosthetic valve replacement is the only curative approach. Glioma-associated oncogene 1 (Gli1) exerts a regulatory role on cardiovascular diseases, and it is already a therapeutic target to combat tumors. Our research aimed to explore the role and basic mechanism of Gli1 in CAVD, to pave the way for the discovery of effective drugs in the treatment of CAVD. Human aortic valve tissues were obtained to evaluate Gli1 expression and primary valve interstitial cells (VICs) were used to perform related experiments. The results showed that Gli1 promoted cell proliferation and significantly accelerated cell osteogenic transformation through the up-regulation of the osteogenic factors Runx2 and Alp, in turn through the AKT signaling pathway by targeting P130cas expression. Furthermore, Gli1 was activated by TGF-β and sonic hedgehog through the canonical and non-canonical Hedgehog signaling pathways in VICs. Our results indicated that Gli1 promoted cell proliferation and accelerated cell osteogenic transformation in VICs, providing a new strategy for the therapy of CAVD by targeting Gli1.

Modified black phosphorus quantum dots promotes spinal cord injury repair by targeting the AKT signaling pathway

Spinal cord injury (SCI) is a serious refractory disease of the central nervous system (CNS), which mostly caused by high-energy trauma. Existing interventions such as hormone shock and surgery are insufficient options, which relate to the secondary inflammation and neuronal dysfunction. Hydrogel with neuron-protective behaviors attracts tremendous attention, and black phosphorus quantum dots (BPQDs) encapsulating with Epigallocatechin-3-gallate (EGCG) hydrogels (E@BP) is designed for inflammatory modulation and SCI treatment in this study. E@BP displays good stability, biocompatibility and safety profiles. E@BP incubation alleviates lipopolysaccharide (LPS)-induced inflammation of primary neurons and enhances neuronal regeneration in vitro. Furthermore, E@BP reconstructs structural versus functional integrity of spinal cord tracts, which promotes recovery of motor neuron function in SCI rats after transplantation. Importantly, E@BP restarts the cell cycle and induces nerve regeneration. Moreover, E@BP diminishes local inflammation of SCI tissues, characterized by reducing accumulation of astrocyte, microglia, macrophages, and oligodendrocytes. Indeed, a common underlying mechanism of E@BP regulating neural regenerative and inflammatory responses is to promote the phosphorylation of key proteins related to AKT signaling pathway. Together, E@BP probably repairs SCI by reducing inflammation and promoting neuronal regeneration via the AKT signaling pathway.

[P2X7R promotes migration and invasion of Lewis lung cancer cells by activating the AKT signaling pathway]

OBJECTIVE

To explore the role of P2X7 receptor (P2X7R) in migration and invasion of mouse Lewis lung cancer (LLC) cells and examine the tumorigenic ability of LLC cells in P2X7R-knockout mice.

METHODS

RT-PCR was used to examine P2X7R mRNA expression in LLC cells. LLC cells were treated with ATP (as a P2X7R agonist) or 2'- 3'- O- (4-benzoyl- benzoyl)-ATP (BzATP) (a P2X7R agonist) with or without pretreatment with P2X7R antagonist oxATP or A438079. The changes in migration and invasive abilities of the cells were evaluated using wound healing assay and Transwell assay; Western blotting was performed to determine the activation level of the key proteins in the AKT signaling pathway. The effects of BzATP, A438079, and LY294002 (a inhibitor of the PI3K/AKT pathway) on migration and invasion of LLC cells were also examined. In wild-type (WT) and P2X7R knockout (P2X7^-/-) C57BL/6 mice, the growth of subcutaneous LLC cell xenografts were observed by measuring tumor volume and weight.

RESULTS

P2X7R expression was detected in LLC cells. Treatment with P2X7R agonist significantly enhanced migration and invasion abilities of LLC cells, and this effect was inhibited by application of P2X7R antagonists (P < 0.001). Western blotting showed that BzATP treatment of LLC cells significantly increased the expression level of p-AKT protein, which was obviously lowered by treatment with P2X7R antagonist (P < 0.01). P2X7R antagonist strongly inhibited BzATP-induced enhancement of LLC cell migration and invasion (P < 0.001). In the tumor- bearing mice, the tumor volume and weight were significantly lower in P2X7^-/- mice than in WT mice (P < 0.05).

CONCLUSION

P2X7R promotes migration and invasion of LLC cells by activating the AKT signaling pathway, and LLC cells show lowered tumorigenic capacity in P2X7^-/- mice.

Physiological and Pathological Functions of Neuronal Hemoglobin: A Key Underappreciated Protein in Parkinson's Disease

The expression of Hemoglobin (Hb) is not restricted to erythrocytes but is also present in neurons. Hb is selectively enriched in vulnerable mesencephalic dopaminergic neurons of Parkinson's disease (PD) instead of resistant neurons. Controversial results of neuronal Hb levels have been reported in postmortem brains of PD patients: although neuronal Hb levels may decline in PD patients, elderly men with higher Hb levels have an increased risk of developing PD. α-synuclein, a key protein involved in PD pathology, interacts directly with Hb protein and forms complexes in erythrocytes and brains of monkeys and humans. These complexes increase in erythrocytes and striatal cytoplasm, while they decrease in striatal mitochondria with aging. Besides, the colocalization of serine 129-phosphorylated (Pser129) α-synuclein and Hb β chains have been found in the brains of PD patients. Several underlying molecular mechanisms involving mitochondrial homeostasis, α-synuclein accumulation, iron metabolism, and hormone-regulated signaling pathways have been investigated to assess the relationship between neuronal Hb and PD development. The formation of fibrils with neuronal Hb in various neurodegenerative diseases may indicate a common fibrillization pathway and a widespread target that could be applied in neurodegeneration therapy.

FOXP4-AS1 Inhibits Papillary Thyroid Carcinoma Proliferation and Migration Through the AKT Signaling Pathway

Papillary thyroid carcinoma, also known as PTC, is one of the commonest malignancies in the endocrine system. Long non-coding RNAs (lncRNAs) in PTC could maintain proliferative signaling, induce therapeutic resistance, activate invasion and migration, and sustain stem cell-like characteristics. In this paper, results showed that lncRNA forkhead box P4 antisense RNA 1 (FOXP4-AS1) is downregulated in PTC tissues and cell lines. Patients in TCGA cohort with a higher FOXP4-AS1 expression showed a higher disease-free interval (DFI) rate, and the expression of FOXP4-AS1 is shown to be linked to the clinical stage, T stage, N stage, and extraglandular invasion condition of the TC patients. FOXP4-AS1 is localized in the cell cytoplasmic domain of PTC cells. Functionally, upregulated FOXP4-AS1 inhibited PTC cell proliferation, apoptosis, and migration, whereas it downregulated FOXP4-AS1-promoted progression of PTC. In vivo assay also confirmed the tumor inhibitory effect of FOXP4-AS1 in PTC growth. Mechanism analysis indicated that FOXP4-AS1 can play its functions by regulating the AKT signaling pathway, and AKT inhibitor treatment could attenuate the impact of FOXP4-AS1 on PTC progression. Furthermore, FOXP4-AS1 also negatively regulates the expression of its host gene FOXP4. Collectively, we showed that FOXP4-AS1 inhibited PTC progression although AKT signaling and FOXP4-AS1 plays a tumor-suppressor role in PTC tumorigenesis.

RNA-seq and ATAC-seq analyses of multilineage differentiating stress enduring cells: Comparison with dermal fibroblasts

The aim of this study is to characterize the molecular properties of multilineage differentiating stress-enduring (Muse) cells compared with dermal fibroblasts (FBs) and to characterize differences in their transcriptomes and open chromatin regions that are involved in cellular plasticity. Assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) and RNA sequencing (RNA-seq) analyses was then performed on FBs and Muse cells. Subsequently, cell type-selective gene regulatory regions were identified by coalition analysis. Expression patterns of transcription factors (TFs) and signaling pathways intermediates were verified using quantitative real-time polymerase chain reaction and Western blot analyses. RNA-seq identified 2355 significantly differentially expressed genes (DEGs) that regulate the transcriptome, including 1222 upregulated and 1133 downregulated DEGs. The general panorama of RNA-seq and ATAC-seq analyses confirmed the differences in TFs and open chromatin regions between FBs and Muse cells. ATAC-seq analysis showed that Muse cells had more reproducible and meaningful peaks than FBs, and the peak signals were concentrated near promoter-transcription start site areas. In genomic regions that can be preferentially accessed in FBs and Muse cells, more than 200 TFs had binding motif sequences. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and coalition analyses identified differences in factors involved in the cell cycle and the protein kinase B (AKT) signaling pathway of FBs and Muse cells. The results of RNA-seq and ATAC-seq analyses clarified the genetic basis of the different biological properties of Muse cells and FBs. These results suggest that the cell cycle transition and the AKT signaling pathway may affect the morphology and biological characteristics of Muse cells.

Whole-Exome Sequencing Identifies a Novel Germline Variant in PTK7 Gene in Familial Colorectal Cancer

Colorectal cancer (CRC) is the third most frequently diagnosed malignancy worldwide. Only 5% of all CRC cases are due to germline mutations in known predisposition genes, and the remaining genetic burden still has to be discovered. In this study, we performed whole-exome sequencing on six members of a Polish family diagnosed with CRC and identified a novel germline variant in the protein tyrosine kinase 7 (inactive) gene (PTK7, ENST00000230419, V354M). Targeted screening of the variant in 1705 familial CRC cases and 1674 healthy elderly individuals identified the variant in an additional familial CRC case. Introduction of this variant in HT-29 cells resulted in increased cell proliferation, migration, and invasion; it also caused down-regulation of CREB, p21 and p53 mRNA and protein levels, and increased AKT phosphorylation. These changes indicated inhibition of apoptosis pathways and activation of AKT signaling. Our study confirmed the oncogenic function of PTK7 and supported its role in genetic predisposition of familial CRC.

Akt Signaling Pathway Is Activated in the Minor Salivary Glands of Patients with Primary Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is an autoimmune exocrinopathy of mainly the salivary and lacrimal glands associated with high prevalence of lymphoma. Akt is a phosphoinositide-dependent serine/threonine kinase, controlling numerous pathological processes, including oncogenesis and autoimmunity. Herein, we sought to examine its implication in pSS pathogenesis and related lymphomagenesis. The expression of the entire and activated forms of Akt (partially and fully activated: phosphorylated at threonine-308 (T308) and serine-473 (S473), respectively), and two of its substrates, the proline-rich Akt-substrate of 40 kDa (PRAS40) and FoxO1 transcription factor has been immunohistochemically examined in minor salivary glands (MSG) of pSS patients (n = 29; including 9 with pSS-associated lymphoma) and sicca-complaining controls (sicca-controls; n = 10). The entire and phosphorylated Akt, PRAS40, and FoxO1 molecules were strongly, uniformly expressed in the MSG epithelia and infiltrating mononuclear cells of pSS patients, but not sicca-controls. Morphometric analysis revealed that the staining intensity of the fully activated phospho-Akt-S473 in pSS patients (with or without lymphoma) was significantly higher than sicca-controls. Akt pathway activation was independent from the extent or proximity of infiltrates, as well as other disease features, including lymphoma. Our findings support that the Akt pathway is specifically activated in MSGs of pSS patients, revealing novel therapeutic targets.

Uev1A promotes breast cancer cell migration by up-regulating CT45A expression via the AKT pathway

Background

UEV1A encodes a ubiquitin-E2 variant closely associated with tumorigenesis and metastasis, but its underlying mechanism in promoting metastasis remains to be investigated.

Methods

In this study, we experimentally manipulated UEV1A and CT45A gene expression and monitored their effects on cancer-related gene expression, cell migration and the signal transduction cascade.

Results

It was found that UEV1A overexpression induces CT45A family gene expression in breast cancer cells. Indeed, ectopic expression of UEV1A was sufficient to induce CT45A and its downstream genes involved in tumorigenesis, epithelial-mesenchymal transition (EMT), stemness and metastasis, and to promote cell migration and EMT signaling. Consistently, depletion of CT45A abolished the above effects, indicating that CT45A is a critical downstream effector of Uev1A. The Uev1A-induced cell migration and EMT signaling was dependent on AKT but independent of NF-κB, indicating that CT45A acts downstream of the AKT pathway.

Conclusions

Based on previous reports and observations in this study, we propose that the Ubc13-Uev1A complex activates AKT through K63-linked polyubiquitination, which leads to enhanced CT45A expression, stimulated cell migration and EMT signaling in breast cells. Since similar effects were also observed in a colorectal cancer cell line, the Ubc13/Uev1A-AKT-CT45A axis may also promote tumorigenesis and metastasis in other tissues.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08750-3.

The regulatory role of pivotal microRNAs in the AKT signaling pathway in breast cancer

Breast cancer is the most prevalent type of cancer among women, and it remains the main challenge despite improved treatments. MicroRNAs (miRNAs) are a small non-coding family of RNAs that play an indispensable role in regulating major physiological processes, including differentiation, proliferation, invasion, migration, cell cycle regulation, stem cell maintenance, apoptosis, and organ development. The dysregulation of these tiny molecules is associated with various human malignancies. More than 50% of these non-coding RNA sequences estimated have been placed on genomic regions or fragile sites linked to cancer. Following the discovery of the first signatures of specific miRNA in breast cancer, numerous researches focused on involving these tiny RNAs in breast cancer physiopathology as a new therapeutic approach or as reliable prognostic biomarkers. In the current review, we focus on recent findings related to the involvement of miRNAs in breast cancer via the AKT signaling pathway and the related clinical implications.

Anti-proliferative activity of disulfiram through regulation of the AKT-FOXO axis: A proteomic study of molecular targets

Due to its potent anti-tumor activity, well-investigated pharmacokinetic properties and safety profile, disulfiram (DSF) has emerged as a promising candidate for drug repurposing in cancer therapy. Although several molecular mechanisms have been proposed for its anti-cancer effects, the precise underlying mechanisms remain unclear. In the present study, we showed that DSF inhibited proliferation of cancer cells by inducing reactive oxygen species (ROS) production, a G1 cell cycle arrest and autophagy. Moreover, DSF triggered apoptosis via suppression of the anti-apoptotic protein survivin. To elucidate the mechanisms for the anti-proliferative activities of DSF, we applied a 2-DE combined with MALDI-TOF-MS/MS analysis to identify differentially expressed proteins in breast cancer cells upon treatment with DSF. Nine differentially expressed proteins were identified among which, three candidates including calmodulin (CaM), peroxiredoxin 1 (PRDX1) and collagen type I alpha 1 (COL1A1) are involved in the regulation of the AKT signaling pathway. The results of western blot analysis confirmed that DSF inhibited p-AKT, suggesting that DSF induces its anti-tumor effects via AKT blockade. Moreover, we found that DSF increased the mRNA levels of FOXO1, FOXO3 and FOXO4, and upregulated the expression of their target genes involved in G1 cell cycle arrest, apoptosis and autophagy. Finally, DSF potentiated the anti-proliferative effects of well-known chemotherapeutic agents such as arsenic trioxide (ATO), doxorubicin, paclitaxel and cisplatin. Altogether, these findings provide mechanistic insights into the anti-growth activities of DSF.

Biological Role of AKT and Regulation of AKT Signaling Pathway by Thymoquinone: Perspectives in Cancer Therapeutics

BACKGROUND

AKT/PKB is an important enzyme with numerous biological functions, and its overexpression is related to carcinogenesis. AKT stimulates different signaling pathways that are downstream of activated tyrosine kinases and phosphatidylinositol 3-kinase, hence functions as an important target for anti-cancer drugs.

OBJECTIVE

In this review article, we have interpreted the role of AKT signaling pathway in cancer and the natural inhibitory effect of Thymoquinone (TQ) in AKT and its possible mechanisms.

METHOD

We have collected the updated information and data on AKT, its role in cancer and the inhibitory effect of TQ in AKT signaling pathway from Google Scholar, PubMed, Web of Science, Elsevier, Scopus, and many more.

RESULTS

Many drugs are already developed, which can target AKT, but very few among them have passed clinical trials. TQ is a natural compound, mainly found in black cumin, which has been found to have potential anti-cancer activities. TQ targets numerous signaling pathways, including AKT, in different cancers. In fact, many studies revealed that AKT is one of the major targets of TQ. The preclinical success of TQ suggests its clinical studies on cancer.

CONCLUSION

This review article summarizes the role of AKT in carcinogenesis, its potent inhibitors in clinical trials, and how TQ acts as an inhibitor of AKT and TQ's future as a cancer therapeutic drug.

YTHDF2 inhibit the tumorigenicity of endometrial cancer via downregulating the expression of IRS1 methylated with m6A

RNA epigenetic modification take part in many biology processes, and the N6-methyladenosine (m⁶A) methylation of specific mRNAs in endometrial cancer (EC) tissues play a key role in regulating the tumorigenicity of EC, but the specific mechanism still unknown and need to be investigated in the future. Here, we found that m⁶A reader protein YTHDF2 expression was significantly upregulated in EC compare to tumor adjacent tissues, YTHDF2 was then identified to inhibit the proliferation and invasion of EC cell lines. Mechanistically, the m⁶A reader YTHDF2 bind the methylation sites of target transcripts IRS1 and promoted IRS1 mRNA degradation, consequently inhibiting the expression of IRS1 and inhibiting IRS1/AKT signaling pathway, finally inhibit the tumorigenicity of EC. Thus, we demonstrated that YTHDF2 inhibited the proliferation and invasion of EC via inhibiting IRS1 expression in m⁶A epigenetic way, which suggests a potential therapeutic target for EC.

MiR-454-3p Promotes Oxaliplatin Resistance by Targeting PTEN in Colorectal Cancer

Colorectal cancer is one of the most common malignancies worldwide. Oxaliplatin is the first-line chemotherapeutic agent for the treatment of advanced colorectal cancer. However, acquired resistance to oxaliplatin limits its therapeutic efficacy, and the underlying mechanism remains largely unclear. In this study, we compared the expression of a panel of microRNAs (miRNAs) between oxaliplatin-sensitive and -resistant HCT-116 colorectal cancer cells. We found that miR-454-3p was significantly up-regulated in oxaliplatin-resistant cells and was the most differently expressed miRNA. Interestingly, we observed that inhibition of miR-454-3p resensitized resistant cells to oxaliplatin and enhanced oxaliplatin-induced cellular apoptosis. Moreover, we determined that miR-454-3p promoted oxaliplatin resistance through targeting PTEN and activating the AKT signaling pathway. In vivo study revealed that overexpression of miR-454-3p decreased the sensitivity of HCT-116 xenograft tumors to oxaliplatin treatment in a mouse model. Clinically, overexpression of miR-454-3p was associated with decreased responsiveness to oxaliplatin-based chemotherapy, as well as a short progression-free survival. Taken together, our study indicated that the expression of miR-454-3p could be used to predict oxaliplatin sensitivity, and targeting miR-454-3p could overcome oxaliplatin resistance in colorectal cancer.

Identification of a new TRAF6 inhibitor for the treatment of hepatocellular carcinoma

Tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) is an E3 ubiquitin ligase that plays a crucial role in signal transduction. Previous studies have demonstrated that TRAF6 is overexpressed in hepatocellular carcinoma (HCC) and that TRAF6 knockdown dramatically attenuates tumor cell growth. Thus, TRAF6 may represent a potential therapeutic target for the treatment of HCC. Herein, we identified bis (4-hydroxy-3,5-dimethylphenyl) sulfone (TMBPS) as a novel inhibitor that can directly bind to and downregulate the level of TRAF6. In vitro experimental results showed that TMBPS arrests the cell cycle in the G2/M phase by inactivating the protein kinase B (AKT) and extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathways and induces apoptosis by activating the p38/mitogen-activated protein kinase (MAPK) signaling pathway. In addition, TMBPS exhibited significant tumor growth inhibition in mouse xenograft models. In summary, our findings offer a proof-of-concept for the use of TMBPS as a novel chemotherapy drug for the prevention or treatment of HCC.

Prenylated flavonoids from Ficus hirta induces HeLa cells apoptosis via MAPK and AKT signaling pathways

A pair of undescribed enantiomers, (±) ficusflavonid A (1a/1b), along with five known analogues, were isolated from the roots of Ficus hirta. Their structures were determined by the analysis of extensive spectroscopic data (including UV, IR, HRESIMS and NMR). Two enantiomers (1a and 1b) were successfully separated by chiral chromatographic column and their absolute configurations were assigned by the comparison of experimental and calculated ECD data. The cytotoxicity of all the isolates against HeLa, MCF-7, HepG2 and H460 cell lines were evaluated by MTT assay. Among them, 4 suppressed the proliferation of HeLa cells with the IC₅₀ value of 28.88 μM. Furthermore, the apoptotic effect of 4 on HeLa cells and the level of several crucial proteins in AKT/MAPKs signaling pathways were analyzed by flow cytometer and western blot assay. As a result, 4 induced HeLa cell apoptosis in a dose dependent manner and significantly increased the protein levels of p-JNK and p-p38, whereas distinctly reduced the expression of p-AKT, and p-ERK. Thus, compound 4 might induce HeLa cells apoptosis via MAPK and AKT signaling pathways, which could be considered as a potential leading compound for the development of anticancer drugs.

Salidroside protects against cardiomyocyte apoptosis and ventricular remodeling by AKT/HO-1 signaling pathways in a diabetic cardiomyopathy mouse model

BACKGROUND

Diabetic cardiomyopathy is characterized by both systolic and diastolic dysfunction due to decreased contractility, as well as reduced compliance of the myocardium. Oxidative stress plays a significant role in diabetes mellitus and its cardiovascular complications. Salidroside, a glucoside of the phenylpropanoid tyrosol, reportedly increases the levels of the antioxidative enzymes, nuclear factor erythroid 2-related factor 2, and heme oxygenase-1 (HO-1) to counteract oxidative stress; however, the underlying mechanisms are poorly understood.

PURPOSE

Here we investigate the potential cardio-protective effects of salidroside and its mechanism in a diabetic animal model.

METHODS

Male db/m, db/db, and age-matched wild-type mice were treated with salidroside at low dose (0.025 mg/kg) or high dose (0.05 mg/kg) by gavage every day for 12 weeks. Cardiac function and structure were assessed by echocardiography and histopathological examination. H9C2 cardiomyocytes were exposed in vitro to advanced glycosylation end products (400 μg/ml) and treated with salidroside (0.1, 1, or 10 μM). The expression of signaling-related genes were explored by western blotting and real-time PCR.

RESULTS

Salidroside treatment significantly improved diabetes-induced cardiac dysfunction, hypertrophy, and fibrosis in vivo. Mechanistically, salidroside markedly up-regulates HO-1 expression by activation of the AKT signaling pathway.

CONCLUSION

Salidroside protects against cardiomyocyte apoptosis and ventricular remodeling in diabetic mice. This cardio-protective effect of salidroside is dependent on AKT signaling activation.

MiR-195-5p Ameliorates Cerebral Ischemia-Reperfusion Injury by Regulating the PTEN-AKT Signaling Pathway

BACKGROUND

MiR-195-5p has been shown to play crucial roles in tumor inhibition, but its biological functions in cerebral ischemia-reperfusion (I/R) injury are unclear.

METHODS

To mimic cerebral I/R injury, mice were induced by transient middle cerebral artery occlusion (MCAO). Human brain microvascular endothelial cells (HBMVECs) were treated with oxygen-glucose deprivation (OGD) to mimic I/R injury in vitro. The expression of miR-195-5p and PTEN was detected by qRT-PCR or Western blot. Cell viability was evaluated by CCK-8 assay. Cell apoptosis was detected by flow cytometer. Cell death was detected using specific lactate dehydrogenase (LDH) cytotoxicity kit. Infarct volume in mice brains was evaluated by TTC staining. Histopathological analysis was performed by HE staining and TUNEL staining. The interaction between miR-195-5p and PTEN was determined by TargetScan and luciferase reporter assay.

RESULTS

MiR-195-5p was significantly downregulated and PTEN was upregulated during cerebral I/R injury both in vitro and in vivo. Overexpression of miR-195-5p efficiently enhanced cell viability, while reduced LDH release and apoptotic rate of OGD-treated HBMVECs in vitro. MiR-195-5p could negatively regulate the expression of PTEN by directly binding to its 3'-UTR. Overexpression of PTEN obviously attenuated the protective effect of miR-195-5p mimics on cell viability, LDH release and apoptosis in OGD-treated HBMVECs. Meanwhile, overexpression of miR-195-5p increased the expression levels of p-AKT in OGD-treated HBMVECs, while this effect was reversed by overexpression of PTEN. Moreover, overexpression of miR-195-5p efficiently ameliorated brain injury of mice after MCAO treatment in vivo.

CONCLUSION

Overexpression of miR-195-5p ameliorated cerebral I/R injury by regulating the PTEN-AKT signaling pathway, providing a potential therapeutic target for cerebral I/R injury.

ACTL6A knockdown inhibits cell migration by suppressing the AKT signaling pathway and enhances the sensitivity of glioma cells to temozolomide

Molecular-targeted therapy has had a significant impact on glioma. Notably, actin-like 6A (ACTL6A) has been indicated to be essential for embryonic development and tumor progression. However, the role of ACTL6A in glioma remains unclear. The present study aimed to investigate the effects of ACTL6A on glioma cell migration and sensitivity to temozolomide (TMZ). The expression levels of ACTL6A were analyzed in patients with glioma, and survival curves were created using data from The Cancer Genome Atlas. U251 and T98G cells were transfected with short hairpin (sh)RNA for use in loss-of-function experiments to investigate the biological function and molecular mechanisms of ACTL6A. Furthermore, an MTT assay was used to assess the effect of ACTL6A on the sensitivity of glioma cells to TMZ. The results demonstrated that ACTL6A was expressed at higher levels in glioma tissues compared with normal brain tissues. Furthermore, high expression of ACTL6A was associated with a poor prognosis. The knockdown of ACTL6A significantly inhibited the migration phenotype in glioma cells and significantly decreased the levels of phosphorylated AKT in glioma cells. The AKT signaling activator SC79 partly attenuated the inhibitory effects of ACTL6A shRNA on glioma cell migration. Additionally, the knockdown of ACTL6A enhanced the sensitivity of glioma cells to TMZ. In conclusion, these results suggest that ACTL6A knockdown inhibited the migration of human glioma cells, at least in part through inactivation of the AKT signaling pathway, and increased the sensitivity of glioma cells to TMZ. Therefore, ACTL6A may be a potential therapeutic target for glioma.

High expression of NEK2 promotes gastric cancer progression via activating AKT signaling

Never in mitosis gene A-related kinase 2 (NEK2) has been recognized as an oncogene involved in the initiation and progression of various human cancers. However, our knowledge is still lacking in regard to the function of NEK2 in gastric cancer, the most common cancer in Eastern Asia associated with poor prognosis. Therefore, in the present study, we investigated the association of NEK2 with gastric cancer. We found that the development of gastric cancer is associated with NEK2 overexpression, particularly in patients with large tumor size and lymph node metastasis. We also provided evidence that NEK2 overexpression binds to and inhibits protein phosphatase 1 (PP1), which subsequently activates AKT and the downstream oncogenic pathways. As a result, via AKT/HIF1α axis, the glucose metabolism is reprogrammed towards aerobic glycolysis to provide rapid energy for the growth of gastric cancer cells. Moreover, the autophagic activity is suppressed via AKT/mTOR axis, leading to impaired response to cancer treatment and enhanced cell survival. In contrast, inactivating AKT by NEK2 silencing decreases aerobic glycolysis and promotes autophagic cell death, which eventually inhibits the growth of gastric cancer cell. All these results revealed that NEK2 promotes gastric cancer progression via activating AKT-mediated signaling pathways, which expanded our knowledge on gastric cancer pathogenesis and also provided novel target for clinical treatment.

MiR-199a-5p inhibition protects cognitive function of ischemic stroke rats by AKT signaling pathway

To explore the effect of miR-199a-5p and AKT signal pathway on cognitive function and neuronal cells in rats with ischemic stroke. Sprague-Dawley rats were divided into 6 groups: Normal group (normal rats), Sham group (rats received sham operation), Model group (MCAO rats), miR-199a-5p inhibitor group (model rats treated with miR-199a-5p inhibitor), IGF-1 group (model rats treated with AKT signaling pathway activator), miR-199a-5p inhibitor + IGF-1 group (model rats treated by miR-199a-5p inhibitor and AKT signaling pathway activator). Rat behavior and cerebral infarction area were observed. TUNEL fluorescence staining was used to detect neuronal apoptosis in hippocampal CA1 region of rats. The dual luciferase reporter assay validated the targeting relationship between miR-199a-5p and AKT. qRT-PCR and WB were used to detect the expression level of miR-199a-5p, (p)-AKT and (p)-mTOR, apoptosis-related proteins Bax and Bcl-2. Compared with the normal group, the expression of miR-199a-5p was increased in the Model group, and the expression levels of AKT, mTOR, p-AKT, and p-mTOR were decreased (all P < 0.05); the cognitive function of the rats in the Model group was thereby significantly lower (P < 0.05). miR-199a-5p was targeted to inhibit AKT. Compared with the Model group, miR-199a-5p inhibition combined with IGF-1 showed more significant effects on improving cognitive function and protecting neuronal cells of rats. In conclusion, silencing miR-199a-5p can effectively improve cognitive function in ischemic stroke rats and decrease neuronal apoptosis in hippocampus by activating the AKT signaling pathway.

Mechanism of tauroursodeoxycholic acid-mediated neuronal protection after acute spinal cord injury through AKT signaling pathway in rats

OBJECTIVE

To explore themechanism of tauroursodeoxycholic acid- (TUDCA) mediated neuronal protection after acute spinal cord injury (ASCI) in rats. Methods: ASCI rat model was established following modified Allen's weight-drop method and these rats were assigned to sham group (received sham operation), model group (ASCI rats), TUDCA group (ASCI rats received TUDCA treatment), MK2206 group (ASCI rats received AKT inhibitor MK2206 orally) and TUDCA + MK2206 group. Motor function of rats was evaluated using Basso Beattie Bresnahan (BBB) method. Hematoxylin-eosin (H&E) staining was used to detect histopathologic changes in the spinal cord and TUNEL fluorescence staining was used to check apoptosis. Real time fluorescence quantitative polymerase chain reaction (qRT-PCR) and western blot were employed to detect the production of AKT pathway related factors, apoptosis related factors (Bax, Bcl-2, caspase-3), autophagy related factor Beclin-1 and endoplasmic reticulum (ER) stress related factors (IRE1, Chop, ATF6) in spinal cord of rats.

RESULTS

Compared to the rats in the sham group, rats in ASCI group had decreased BBB scores (P<0.05), more significant tissue edema, structural cavity and apoptosis. Compared to rats in sham group, AKT pathway was inactivated in ASCI rats and was activated by TUDCA treatment (P<0.05). Compared to sham group, expressions of ER stress-related factors were increased, apoptosis was largely induced in other four groups, and expression of Beclin-1 was increased in the model group (P<0.05). TUDCA increased the expression of Beclin-1 and Bcl-2, and inhibited the expression of Bax, Caspase-3, and ER stress-related factors, thus suppressing apoptosis (P<0.05). Treatment by MK2206 had contrary effects and protective effects of TUDCA on ASCI rats could be counteracted by MK2206.

CONCLUSION

TUDCA can significantly improve the neural damage, enhance neuron autophagy, alleviate ER stress, and inhibit apoptosis in ASCI rats, by activating the AKT signaling pathway.

Resveratrol inhibits proliferation and promotes apoptosis via the androgen receptor splicing variant 7 and PI3K/AKT signaling pathway in LNCaP prostate cancer cells

Prostate cancer is a common malignant tumor of the male genitourinary system and its incidence increases with age. Studies have shown that resveratrol (Res) inhibits cancer cell proliferation, migration, invasion and promotes apoptosis. The present study evaluated the effect of Res in two human prostate cancer cell lines (the androgen-dependent LNCaP cell line and the non-androgen-independent LNCaP-B cell line) on proliferation and apoptosis. A proliferation assay was used to demonstrate that Res inhibited proliferation of LNCaP and LNCaP-B cells in the range of 25–100 µM, and the effect was time- and dose-dependent. Using flow cytometry, it was reported that various concentrations of Res induced apoptosis in LNCaP and LNCaP-B cells, and that the apoptotic effect of Res was dose-dependent. A chemiluminescence assay showed that Res inhibited prostate specific antigen levels in LNCaP and LNCaP-B cells. Reverse transcription quantitative-PCR showed that Res inhibited the expression of androgen receptor (AR) in LNCaP and LNCaP-B cells at the mRNA level. Western blot analysis showed that Res suppressed the expression of AR protein as well as protein kinase B (AKT) phosphorylation. To study the effect of Res on the expression of AR splicing variant 7 (ARV7) and the PI3K/AKT signaling pathway in prostate cancer cells, as well as the underlying molecular mechanisms, the recombinant ARV7 expression vector Pcdna3.1-ARV7 was transfected into LNCaP and LNCaP cells and the aforementioned experiments were repeated. It was revealed that Res acted via the ARV7 and the AKT pathways. Taken together, the present results suggested that Res suppresses the proliferation of prostate cancer cells, promotes apoptosis and inhibits the expression of AR mRNA and protein. These effects likely resulted from inhibition of ARV7 and the AKT signaling pathway.

Long noncoding RNA LEF1-AS1 acts as a microRNA-10a-5p regulator to enhance MSI1 expression and promote chemoresistance in hepatocellular carcinoma cells through activating AKT signaling pathway

Long noncoding RNAs (lncRNAs) contribute to the development of hepatocellular carcinoma (HCC), which could regulate various HCC biological characteristics. Here, the study seeks to investigate the role of lncRNA LEF1-AS1 in HCC cell chemoresistance by regulating microRNA (miR)-10a-5p and Musashi1 (MSI1). The microarray-based analysis was employed to identify the HCC-related lncRNA-miRNA-gene regulatory network. Expression patterns of LEF1-AS1, miR-10a-5p, and MSI1 in the HCC cell lines, tissues were accessed by means of reverse transcription-quantitative polymerase chain reaction. Next, the interaction among LEF1-AS1, miR-10a-5p, and MSI1 in HCC was accessed by bioinformatics and dual-luciferase reporter gene assay. Then, the cell line resistant to cisplatin was established, which was then treated with sh/oe-lncRNA LEF1-AS1, miR-10a-5p-mimic, and oe/sh-MSI1 vectors alone or in combination. Afterward, the effect of LEF1-AS1, miR-10a-5p, and MSI1 on HCC cell chemoresistance, proliferation, and apoptosis was assessed. At last, in vivo experiments confirmed the role of MSI1 in tumor growth and chemoresistance in HCC. LEF1-AS1 might potentially affect the growth and chemoresistance of HCC cells by regulating miR-10a-5p and MSI1. LEF1-AS1 and MSI1 expression patterns were elevated, while miR-10a-5p was repressed in HCC tissues and cell lines. LEF1-AS1 combined to miR-10a-5p and regulated MSI1, thereby activating the protein kinase B (AKT) signaling pathway. Knockdown of LEF1-AS1 and MSI1 or elevation of miR-10a-5p compromised the proliferation of Huh7 cell line resistant to DDP and promoted its chemosensitivity and apoptosis. At last, these in vitro findings were also confirmed in vivo. Our results unraveled LEF1-AS1 acts as a miR-10a-5p modulator to promote chemoresistance of HCC cells by stimulating MSI1 and activating the AKT signaling pathway, which might provide a novel therapeutic target for HCC.

Osteocyte-derived exosomes induced by mechanical strain promote human periodontal ligament stem cell proliferation and osteogenic differentiation via the miR-181b-5p/PTEN/AKT signaling pathway

BACKGROUND

The oral cavity is a complex environment in which periodontal tissue is constantly stimulated by external microorganisms and mechanical forces. Proper mechanical force helps maintain periodontal tissue homeostasis, and improper inflammatory response can break the balance. Periodontal ligament (PDL) cells play crucial roles in responding to these challenges and maintaining the homeostasis of periodontal tissue. However, the mechanisms underlying PDL cell property changes induced by inflammatory and mechanical force microenvironments are still unclear. Recent studies have shown that exosomes function as a means of cell-cell and cell-matrix communication in biological processes.

METHODS

Human periodontal ligament stem cells (HPDLSCs) were tested by the CCK8 assay, EdU, alizarin red, and ALP staining to evaluate the functions of exosomes induced by a mechanical strain. MicroRNA sequencing was used to find the discrepancy miRNA in exosomes. In addition, real-time PCR, FISH, luciferase reporter assay, and western blotting assay were used to investigate the mechanism of miR-181b-5p regulating proliferation and osteogenic differentiation through the PTEN/AKT pathway.

RESULTS

In this study, the exosomes secreted by MLO-Y4 cells exposed to mechanical strain (Exosome-MS) contributed to HPDLSC proliferation and osteogenic differentiation. High-throughput miRNA sequencing showed that miR181b-5p was upregulated in Exosome-MS compared to the exosomes derived from MLO-Y4 cells lacking mechanical strain. The luciferase reporter assay demonstrated that miR-181b-5p may target phosphatase tension homolog deletion (PTEN). In addition, PTEN was negatively regulated by overexpressing miR-181b-5p. Real-time PCR and western blotting assay verified that miR-181b-5p enhanced the protein kinase B (PKB, also known as AKT) activity and improved downstream factor transcription. Furthermore, miR-181b-5p effectively ameliorated the inhibition of HPDLSC proliferation and promoted HPDLSC induced by inflammation.

CONCLUSIONS

This study concluded that exosomes induced by mechanical strain promote HPDLSC proliferation via the miR-181b-5p/PTEN/AKT signaling pathway and promote HPDLSC osteogenic differentiation by BMP2/Runx2, suggesting a potential mechanism for maintaining periodontal homeostasis.

Up-regulation of microRNA-335-5p reduces inflammation via negative regulation of the TPX2-mediated AKT/GSK3β signaling pathway in a chronic rhinosinusitis mouse model

Chronic rhinosinusitis (CRS) is featured with chronic symptoms of inflammation or infection in the nasal and sinus tissues. MicroRNAs (miRNAs/miRs), such as dysregulated expression of miR-125b and miR-26a, has been previously demonstrated to be related to CRS. The present study is intended to define the role of miR-335-5p in inflammation and the related mechanism in a mouse model of CRS. The differentially expressed genes associated with CRS were screened by microarray analysis. The targeting relationship between miR-335-5p and TPX2 was analyzed by target prediction program and dual luciferase reporter gene assay. The mouse model of CRS was established, and mice were introduced with miR-335-5p mimics, miR-335-5p inhibitors, or siRNA against TPX2 to explore the regulatory functions of miR-335-5p. The regulatory effect of miR-335-5p on inflammation with the involvement of the AKT signaling pathway was also analyzed with the expression of inflammatory cytokines and AKT signaling pathway-related factors measured. It was indicated that miR-335-5p regulated the TPX2 gene-mediated AKT signaling pathway. TPX2 was identified as a target gene of miR-335-5p, and miR-335-5p elevation inhibited the activation of the AKT signaling pathway. In mice with CRS, up-regulation of miR-335-5p or silence of TPX2 inhibited the inflammation, as evidenced by decreased levels of TNF-α, IL-6 and IL-8, and higher levels of GSK3β and IL-10. Collectively, miR-335-5p inhibits the activation of AKT signaling pathway by negatively mediating TPX2, which may confer anti-inflammatory protection in CRS.

MiR-214 Mediates Cell Proliferation and Apoptosis of Nasopharyngeal Carcinoma Through Targeting Both WWOX and PTEN

Background: This study aimed to investigate interactions between miR-214, PTEN, and WWOX and their effect on AKT signaling during the NPC progression. Nasopharyngeal carcinoma (NPC) was highly prevalent with poor prognosis among the patients. MiR-214 reported as an important NPC biomarker was associated with regulation of biological functions.

Methods: 5–8F and 6–10B NPC cells were transfected with miR-214 inhibitor. MTT and colony formation assays were performed to assess cell proliferation. PI staining assay was performed to determine distribution of cell cycle. Annexin-V/PI staining assay was used to evaluate cell apoptosis in NPC. The effects of miR-214 inhibitor on the expression levels of PTEN, WWOX, AKT signaling pathway, cell-cycle-, and apoptosis-associated proteins were assessed by Western blotting or qRT-PCR assay. PTEN and WWOX were knocked down using the corresponding shRNA to investigate their effects on miR-214 inhibitor involved in proapoptosis and antiproliferation mechanisms in NPC.

Results: Inhibition of miR-214 suppressed cell growth and induced apoptosis of 5–8F and 6–10B cells. MiR-214 regulated the expression of both PTEN and WWOX through targeting the 3′-UTR. Inhibition of miR-214 promoted WWOX and PTEN expression, inactivated AKT signaling pathway, and regulated cell-cycle- and apoptosis-associated proteins. Knockdown of PTEN or WWOX reversed effects of miR-214 inhibitor on AKT signaling, cell proliferation, and apoptosis.

Conclusion: MiR-214 was suggested to induce cell proliferation and inhibit cell apoptosis of NPC through directly targeting both PTEN and WWOX, which provided a novel therapeutic target for clinical treatment of NPC.

The role of fibroblast activation protein in progression and development of osteosarcoma cells

To investigate the expression levels of fibroblast activation protein (FAP) in human osteosarcoma tissues and its possible correlations with clinical pathological characteristics of patients with osteosarcoma, and to explore the potential effects of FAP on progression and development of osteosarcoma. Immunohistochemistry (IHC) assay was initially performed to detect the expression levels of FAP in 66 tumor tissues and adjacent non-tumor tissues. Patients were sequentially divided into two groups based on different expression levels of FAP. The correlations between the expression levels of FAP and the clinical pathological characteristics were investigated, and the role of FAP in proliferation, migration, and invasion of osteosarcoma cells was assessed via colony formation, MTT, wound healing, and transwell assays, respectively. The possible effects of FAP on tumor growth and metastasis were evaluated in vivo. We further attempted to reveal the underlying mechanism of FAP involved in tumor growth through bioinformatics and IHC assays. High expression levels of FAP were noted in human osteosarcoma tissues. It also was unveiled that FAP was significantly associated with the tumor size (P = 0.005*) and clinical stage (P = 0.017*). Our data further confirmed that knockdown of FAP remarkably blocked proliferation, migration, and invasion of osteosarcoma cells in vitro, and suppressed tumor growth and metastasis in mice via AKT signaling pathway. The possible role of FAP in progression and development of osteosarcoma could be figured out. Our data may be helpful to develop a novel therapeutic target for the treatment of osteosarcoma.

Long noncoding RNA HOTAIR promotes breast cancer development by targeting ZEB1 via sponging miR-601

BACKGROUND

Breast cancer (BC) is a common malignancy worldwide. It has been reported that long non-coding RNA (lncRNA) HOX transcript antisense RNA (HOTAIR) is abnormally expressed in BC. However, the role of HOTAIR in the malignancy of BC is worth further discussion. This study aims to clarify the function and molecular mechanism of HOTAIR in BC.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to determine the expression of HOTAIR, microRNA (miR)-601 and zinc finger E-box binding homeobox 1 (ZEB1). Cell counting kit-8 (CCK-8) and transwell assay were used to detect the proliferation, migration and invasion of cells. Further, the protein levels of AKT, phosphorylated-AKT (p-AKT), ZEB1 and Ki-67 were confirmed by western blot (WB) assay. Moreover, dual-luciferase reporter assay was applied to examine the targeting relationship between HOTAIR and miR-601 or miR-601 and ZEB1. In addition, animal experiments were conducted to verify the effect of HOTAIR on BC tumor growth in vivo.

RESULTS

HOTAIR was upregulated in BC tissues and cells, and its knockdown suppressed the proliferation, migration, invasion and the activity of AKT signaling pathway of BC cells. HOTAIR could serve as a sponge of miR-601. Further experiments revealed that miR-601 inhibitor could reverse the inhibition effect of HOTAIR silencing on the progression of BC. Meanwhile, ZEB1 was a target of miR-601, and its overexpression could invert the suppression effect of miR-601 overexpression on the progression of BC. Additionally, ZEB1 expression was regulated by HOTAIR and miR-601. Furthermore, interference of HOTAIR could attenuate BC tumor growth in vivo.

CONCLUSION

In short, this study demonstrated that HOTAIR promoted the proliferation, migration, invasion of BC through regulating the miR-601/ZEB1 axis, which provided a theoretical basis for the research on lncRNA-directed therapeutics in BC.

LINC00462 is involved in high glucose-induced apoptosis of renal tubular epithelial cells via AKT pathway

New evidences suggest that long non-coding RNAs (lncRNAs) may play important roles in a variety of kidney diseases, including diabetic nephropathy (DN). Our present study investigated the potential function of LINC00462 in high glucose (HG)-induced apoptosis of renal tubular epithelial cells (RTEC) and to determine the underlying mechanism. The expression of LINC00462 in renal biopsy tissues was examined using quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Then, a loss of function assay was performed to determine the protective effect of LINC00462 in HG-induced RTEC damage. In addition, the downstream signaling pathway of LINC00462 was also investigated. The qRT-PCR results showed that the expression of LINC00462 was significantly up-regulated in renal biopsies from DN patients. At the same time, LINC00462 was enhanced in a glucose concentration- and time-dependent manner in human kidney (HK-2 and HKC) cells subjected to HG treatment. The knockdown of LINC00462 improved the significantly reduced cell viability of HG treatment, decreased HG-induced reactive oxygen species (ROS) and malondialdehyde levels, and up-regulated the response of antioxidant systems to ROS by increasing superoxide dismutase and catalase levels. In addition, knockdown of LINC00462 inhibited HG-induced cell apoptosis and affected the expression of apoptosis-related proteins. Most importantly, we found that knockdown of LINC00462 enhanced the expression of p-AKT. Moreover, AKT-specific inhibitor LY294002 restored the effect of LINC00462 knockdown on apoptosis. In conclusion, our study demonstrated that knockdown of LINC00462 can ameliorate oxidative stress and apoptosis in HG-induced RTEC by activating the AKT pathway, suggesting that knockdown of LINC00462 may provide a potential therapeutic approach for DN.

MSC-Secreted Exosomal H19 Promotes Trophoblast Cell Invasion and Migration by Downregulating let-7b and Upregulating FOXO1

Exosomes perform important functions for intercellular communication through extracellular signaling pathways, leading to the regulation of important biological processes, including cell proliferation, but also systemic dysfunctions such as preeclampsia (PE). However, the inhibitory effects of mesenchymal stem cell (MSCs)-derived exosomes in PE remain largely unknown. Thus, we assessed the possibility that exosomes could transport long non-coding RNA H19 and the correlation between H19 and the apoptosis of trophoblast cells. The expression of microRNA let-7b and forkhead box protein O1 (FOXO1) was characterized in placental tissues of PE patients. Gain- and loss-of-function experiments were performed to examine the roles of FOXO1 and let-7b in trophoblast cells. Interactions between let-7b and H19 as well as between let-7b and FOXO1 were confirmed by a dual-luciferase reporter assay, RNA pull-down, and RNA immunoprecipitation. HTR-8/SVneo cells were co-cultured with exosomes derived from MSCs overexpressing H19, followed by invasion, migration, and apoptosis assessments of trophoblast cells. We found that let-7b was highly expressed and FOXO1 was poorly expressed in placental tissues of PE patients. Furthermore, H19 acts as a competitive endogenous RNA against let-7b, and let-7b directly targeted FOXO1. Moreover, H19 could be transferred to trophoblast cells via MSC-secreted exosomes. MSC-derived exosomes overexpressing H19 decreased let-7b, increased FOXO1, and activated the protein kinase B (AKT) signaling pathway, thus increasing invasion and migration and inhibiting apoptosis of trophoblast cells. These results suggest that MSC-derived exosomes overexpressing H19 may be a novel direction for therapeutic strategies against PE.

TEX9 and eIF3b functionally synergize to promote the progression of esophageal squamous cell carcinoma

Background

Esophageal squamous cell carcinoma (ESCC) is one of the most frequent malignant digestive tumors around the world. We previously demonstrated that eIF3b could promote the progression of ESCC. The exact mechanisms underlying these effects remained unknown.

Methods

Quantitative proteomics was applied to detect the potential targets of Eukaryotic translation initiation factor 3 subunit b (eIF3b). RT-qPCR and Western blot were performed to detect the expression of targeted gene and pathway related genes. RNA-immunoprecipitation was applied to verify the binding of eIF3b with targeted gene. Moreover, CCK-8 assay, colony-formation assay, transwell assay, flow cytometry for cell apoptosis and tumor xenograft assay were performed to analyze the regulation of the targeted gene on the bio-function of ESCC cells.

Results

Quantitative proteomics data showed that Testis-expressed protein 9 (TEX9) expression was positively associated with eIF3b expression. RT-qPCR and Western blot results confirmed the quantitative proteomics data and demonstrated that TEX9 expression was positively correlated with TNM stage in ESCC. Furtherly, RNA-immunoprecipitation confirmed that eIF3b binding to TEX9 mRNA. The bio-function related assay demonstrated that TEX9 and eIF3b functionally synergized to promote the proliferation and migration, and inhibited the apoptosis of ESCC cells. In the analysis of mechanism, we revealed that TEX9 and eIF3b promoted the progression of ESCC through the activation of AKT signaling pathway.

Conclusions

The synergized promoting role of TEX9 and eIF3b in the progression of ESCC may provide a novel mechanism for exploring viable therapeutic strategies for ESCC.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-6071-9) contains supplementary material, which is available to authorized users.

Targeted therapy of the AKT kinase inhibits esophageal squamous cell carcinoma growth in vitro and in vivo

Esophageal cancer, a leading cause of cancer death worldwide, is associated with abnormal activation of the AKT signaling pathway. Xanthohumol, a prenylated flavonoid tested in clinical trials, is reported to exert anti-diabetes, anti-inflammation and anticancer activities. However, the mechanisms underlying its chemopreventive or chemotherapeutic effects remain elusive. In the present study, we found that xanthohumol directly targeted AKT1/2 in esophageal squamous cell carcinoma (ESCC). Xanthohumol significantly inhibited the AKT kinase activity in an ATP competitive manner, which was confirmed in binding and computational docking models. KYSE70, 450 and 510 ESCC cell lines highly express AKT and knockdown of AKT1/2 suppressed proliferation of these cells. Treatment with xanthohumol inhibited ESCC cell growth and induced apoptosis and cell cycle arrest at the G1 phase. Xanthohumol also decreased expression of cyclin D1 and increased the levels of cleaved caspase-3, -7 and -PARP as well as Bax, Bims and cytochrome c in ESCC cells by downregulating AKT signaling targets, including glycogen synthase kinase 3 beta (GSK3β), mammalian target of rapamycin, and ribosomal protein S6 (S6K). Furthermore, xanthohumol decreased tumor volume and weight in patient-derived xenografts (PDXs) that highly expressed AKT, but had no effect on PDXs that exhibited low expression of AKT in vivo. Kinase array results showed that xanthohumol treatment decreased phosphorylated p27 expression in both ESCC cell lines and PDX models. Taken together, our data suggest that the inhibition of ESCC tumor growth with xanthohumol is caused by targeting AKT. These results provide good evidence for translation toward clinical trials with xanthohumol.

Down-regulated microRNA-30b-3p inhibits proliferation, invasion and migration of glioma cells via inactivation of the AKT signaling pathway by up-regulating RECK

microRNAs (miRNAs) have been found to affect various cancers, and expression of numerous miRNAs is revealed in glioma. However, the role of microRNA-30b-3p (miR-30b-3p) in glioma remains elusive. Therefore, the present study aims to explore the specific mechanism by which miR-30b-3p influence the development of glioma in relation to the AKT signaling pathway. First, glioma cell lines were collected with miR-30b-3p and reversion-inducing cysteine-rich protein with kazal motifs (RECK) expression measured. The functional role of miR-30b-3p and RECK in glioma was determined via gain- and loss-of-function approaches. Subsequently, the expression of invasion- and migration-related factors (MMP-2 and MMP-9) and the AKT signaling pathway-related factors (AKT, p-AKT and PI3K-p85) was detected. Moreover, in vivo experiments were also conducted to investigate how miR-30b-3p influences in vivo tumorigenesis. The results showed that miR-30b-3p was up-regulated and RECK was down-regulated in glioma. RECK was a target gene of miR-30b-3p. Decreased miR-30b-3p and overexpressed RECK led to decreased expression of MMP-2, MMP-9 and p-AKT. Overexpressed RECK and LY294002 could decrease p-AKT and PI3K-p85 expression accompanied with unchanged expression of total protein of AKT. Additionally, proliferation, migration and invasion of glioma cells and tumor formation in nude mice were repressed owing to reduced expression of miR-30b-3p or elevated expression of RECK. In summary, miR-30b-3p inhibition suppresses metastasis of glioma cells by inactivating the AKT signaling pathway via RECK up-regulation, providing a new target for glioma treatment.

MicroRNA-203 Acts as a Potent Suppressor in Septic Shock by Alleviating Lung Injury via Inhibition of VNN1

BACKGROUND

Septic shock, the most serious complication of sepsis, is a life-threatening disease that is mainly characterized by hypoperfusion and multiple organ failure. Various aberrantly expressed microRNAs (miRNAs) have been reported to be related to septic shock. We explored the regulatory effect of microRNA-203 (miR-203) on lung injury in septic shock mice.

METHODS

Microarray-based gene expression profiling related to septic shock identified the differentially expressed gene vanin-1 (VNN1) and potential regulatory miR-203. miR-203 was predicted to mediate VNN1 expression, thus affecting septic shock, which was investigated by treatment with miR-203 mimic, miR-203 inhibitor, and siRNA-VNN1 in septic shock mouse models. Polymorphonuclear neutrophils (PMNs) and pulmonary alveolar macrophages in bronchoalveolar lavage fluid (BALF) as well as the wet/dry ratio of the lung were also measured to assess lung injury. Additionally, the effects of miR-203 on inflammatory cytokines, oxidative stress indexes, blood biochemical indexes, serine-threonine protein kinase (AKT) signaling pathway-related factors, and apoptosis-related factors were determined.

RESULTS

VNN1 was verified to be targeted and negatively regulated by miR-203. In mouse models of septic shock, weak expression of miR-203, high expression of VNN1, and inhibition of AKT signaling pathway were identified. In response to miR-203 mimic and VNN1 gene silencing, mouse models of septic shock displayed reduced apoptosis, MDA, ALT, and AST in lung tissues, decreased levels of TNF-α, IL-1β, IFN-γ, IL-10, and IL-6, in serum, and reduced PMN and PAM levels in BALF, in addition to elevated SOD activity. Notably, the presence of miR-203 mimic led to AKT signaling pathway activation.

CONCLUSION

This study shows that upregulating miR-203 can alleviate lung injury through activation of the AKT signaling pathway by downregulating VNN1 in septic shock.

microRNA-613 exerts anti-angiogenic effect on nasopharyngeal carcinoma cells through inactivating the AKT signaling pathway by down-regulating FN1

Background: Nasopharyngeal carcinoma (NPC) is a disease highly sensitive to radiotherapy with the unclear etiology. However, the specific effects of microRNA-613 (miR-613) on NPC still remain elusive. Therefore, the present study probes into the underlying mechanism of miR-613 in NPC via AKT signaling pathway by regulating Fibronectin 1 (FN1).

Methods: First, microarray analysis was used to screen differentially expressed genes (DEGs) and regulatory miRs associated with NPC. Next, miR-613 and FN1 expression in NPC cells was determined, followed by verification of target relationship between miR-613 and FN1. With NPC cells exposed to miR-613 mimic, si-FN1 and LY294002 (inhibitor of AKT signaling pathway), the regulatory effects of miR-613 on proliferation, apoptosis, invasion, migration and angiogenesis of NPC cells were detected with ratio of B-cell lymphoma 2/Bcl-2-associated X protein (Bcl-2/Bax), Cleaved-caspase3, matrix metallopeptidase 2 (MMP-2), MMP-9, vascular endothelial growth factor (VEGF), and cell adhesion molecule-1 (CD31) expression measured. Then, tumorigenesis and MVD were determined after Xenograft in nude mice.

Results: FN1 modulated by miR-613 was critical for NPC via the AKT signaling pathway. NPC cells exhibited down-regulated miR-613 and up-regulated FN1. Besides, miR-613 was verified to target FN1. Moreover, overexpressed miR-613, silenced FN1 or LY294002 treatment suppressed proliferation, invasion, migration, and angiogenesis in NPC cells, which was indicated by reduced expression of AKT, mTOR, MMP-2, MMP-9, VEGF, and CD31 as well as decreased ratio of Bcl-2/Bax and increased expression of Cleaved-caspase3. Furthermore, cell apoptosis was promoted and tumorigenesis and MVD in nude mice were inhibited with overexpression of miR-613, silenced FN1 or LY294002 treatment.

Conclusion: Taken together, miR-613 inhibits angiogenesis in NPC cells through inactivating FN1-dependent AKT signaling pathway.

A Novel AURKA Mutant-Induced Early-Onset Severe Hepatocarcinogenesis Greater than Wild-Type via Activating Different Pathways in Zebrafish

Aurora A kinase (AURKA) is an important regulator in mitotic progression and is overexpressed frequently in human cancers, including hepatocellular carcinoma (HCC). Many AURKA mutations were identified in cancer patients. Overexpressing wild-type Aurka developed a low incidence of hepatic tumors after long latency in mice. However, none of the AURKA mutant animal models have ever been described. The mechanism of mutant AURKA-mediated hepatocarcinogenesis is still unclear. A novel AURKA mutation with a.a.352 Valine to Isoleucine (V352I) was identified from clinical specimens. By using liver-specific transgenic fish overexpressing both the mutant and wild-type AURKA, the AURKA(V352I)-induced hepatocarcinogenesis was earlier and much more severe than wild-type AURKA. Although an increase of the expression of lipogenic enzyme and lipogenic factor was observed in both AURKA(V352I) and AURKA(WT) transgenic fish, AURKA(V352I) has a greater probability to promote fibrosis at 3 months compared to AURKA(WT). Furthermore, the expression levels of cell cycle/proliferation markers were higher in the AURKA(V352I) mutant than AURKA(WT) in transgenic fish, implying that the AURKA(V352I) mutant may accelerate HCC progression. Moreover, we found that the AURKA(V352I) mutant activates AKT signaling and increases nuclear β-catenin, but AURKA(WT) only activates membrane form β-catenin, which may account for the differences. In this study, we provide a new insight, that the AURKA(V352I) mutation contributes to early onset hepatocarcinogenesis, possibly through activation of different pathways than AURKA(WT). This transgenic fish may serve as a drug-screening platform for potential precision medicine therapeutics.

miR-96-5p promotes the proliferation and migration of ovarian cancer cells by suppressing Caveolae1

BACKGROUND

Ovarian cancer (OC) is the second most common gynaecological malignancy. MicroRNAs (miRNAs) have been found to be aberrantly expressed in OC tissue and have been proposed as biomarkers and therapeutic targets for OC.

RESULTS

In this study, we found that miR-96-5p was up-regulated in OC tissues and OC cells compared to normal ovarian tissues and epithelial cell line. And, miR-96-5p was also up-regulated in the serum samples from OC patients compared to health participants. In addition, there was a positive correlation of miR-96-5p levels between OC tissues and serum samples. At the cellular level, overexpression of miR-96-5p promoted cell proliferation and migration in OC cells. Moreover, we further validated Caveolae1 (CAV1) as the direct target of miR-96-5p in OC cells through luciferase activity assays and western blot. CAV1 was obvious low expression in OC tissues. The overexpression of CAV1 abrogated the promotion of miR-96-5p on the OC cells proliferation and migration. Finally, we found that AKT signaling pathway was involved in this process. MiR-96-5p inhibited the phosphorylation of AKT and expression of down-stream proteins Cyclin D1 and P70 by targeting CAV1.

CONCLUSIONS

The above findings suggested that targeting miR-96-5p may be a promising strategy for OC treatment.

High-mobility group box 2 promoted proliferation of cervical cancer cells by activating AKT signaling pathway

Cervical cancer is one of the leading killers for female worldwide. Nevertheless, the less knowledge of molecular mechanism for cervical cancer limited the improvement of treatment effects. High-mobility group box 2 (HMGB2) belongs to the HMGB family, which could play diverse roles in cell proliferation. This work mainly aimed to study the functions of HMGB2 on cervical cancer cells proliferation. HMGB2 was highly expressed in cervical cancer tissue. The results of real-time polymerase chain reaction and Western blot analysis showed that HMGB2 was expressed in all the five cervical cancer cells (HeLa, CaSki, SiHa, C-33A, and C4-1 cells). In addition, HMGB2 overexpression obviously improved cell viability and promoted cell cycle progression, which suggested that HMGB2 could promote proliferation of cervical cancer cells. Moreover, HMGB2 overexpression increased the level of p-AKT and reduced the levels of p21 and p27. However, HMGB2 downregulation had contrary influences on cell proliferation, cell cycle distribution and the levels of p-AKT, p21, and p27. Notably, LY294002, as an inhibitor of AKT signaling pathway, could significantly weaken the effects of HMGB2 overexpression, which indicated that HMGB2 might promote cell proliferation by activating AKT signaling pathway. Therefore, HMGB2 was hopeful to be a candidate as a new biomarker and therapy target for cervical cancer.

Inhibition of CTRP6 prevented survival and migration in hepatocellular carcinoma through inactivating the AKT signaling pathway

C1qTNF-related proteins (CTRPs) are a member of the adiponectin paralogs family, which are implicated in regulation of various biological processes. Recently, CTRP6 was found upregulated in human hepatocellular carcinomas (HCC). However, the specific roles and molecular mechanisms of CTRP6 in HCC remain unclear. Here, we investigated the effects of CTRP6 on the vitality, apoptosis, migration, and invasion of HCC cells. Firstly, we measured the levels of CTRP6 in HCC tissues and cell lines. Our results showed that CTRP6 was markedly upregulated in HCC tissues and Hep3B cells. Then, the CTRP6 siRNA was transfected into Hep3B cells. Cell counting kit-8 (CCK-8) assay and flow cytometry analysis revealed that silencing CTRP6-induced cell viability inhibition, and apoptosis. The wound-healing and transwell assay showed that CTRP6 deficiency suppressed the migration and invasion of Hep3B cells. Meanwhile, the AKT phosphorylation level was reduced by CTRP6 silencing. Next, Hep3B cells were pretreated with insulin-like growth factor-1 (IGF-1) (an activator of AKT), and then transfected with CTRP6 siRNA, and the cell vitality, apoptosis, migration, and invasion were measured again. We found that all these alterations caused by CTRP6 inhibition could be reversed by IGF-1 treatment. Taken together, CTRP6 suppression blocked cell survival, migration, and invasion and promoted cell apoptosis through inactivating the AKT signaling pathway. Our findings present a novel potential molecular target for HCC therapy.

MDA19, a novel CB2 agonist, inhibits hepatocellular carcinoma partly through inactivation of AKT signaling pathway

Background

CB₂ (cannabinoid receptor 2) agonists have been shown to exert anti-tumor activities in different tumor types. However, there is no study exploring the role of MDA19 (a novel CB₂ agonist) in tumors. In this study we aimed to investigate the effects of MDA19 treatment on HCC cell lines, Hep3B and HepG2 and determine the relevant mechanisms.

Results

Cell proliferation analysis, including CCK8 and colony formation assays, indicated that MDA19 treatment inhibited HCC cell proliferation in a dose- and time-dependent manner. Flow cytometry suggested that MDA19 induced cell apoptosis and activation of mitochondrial apoptosis pathway. Transwell assay indicated that HCC cell migration and invasion were significantly inhibited by MDA19 treatment. Mechanism investigation suggested that MDA19 induced inactivation of AKT signaling pathway in HCC cells. In addition, we investigated the function of CB₂receptor in HCC and its role in the anti-tumor activity of MDA19. By searching on Kaplan-Meier plotter (http://kmplot.com/analysis/), we found that HCC patients with high CB₂ expression had a better survival and CB2 expression was significantly associated with gender, clinical stages and race of HCC patients (P < 0.05). CB₂ inhibited the progression of HCC cells and its knockdown could rescue the growth inhibition induced by MDA19 in HCC. Moreover, the inhibitory effect of MDA19 on AKT signaling pathway was also reversed by CB₂ knockdown.

Conclusion

Our data suggest that MDA-19 exerts an anti-tumor activity at least partly through inactivation of AKT signaling pathway in HCC. CB₂ functions as a tumor suppressor gene in HCC, and MDA19-induced growth inhibition of HCC cells depends on its binding to CB₂ to activate it. MDA-19 treatment may be a promising strategy for HCC therapy.

Reviewer

This article was reviewed by Tito Cali, Mohamed Naguib and Bo Chen.