MicroRNA-185 induces potent autophagy via AKT signaling in hepatocellular carcinoma

MicroRNAs in Hepatocellular Carcinoma Pathogenesis: Insights into Mechanisms and Therapeutic Opportunities

Hepatocellular carcinoma (HCC) presents a significant global health burden, with alarming statistics revealing its rising incidence and high mortality rates. Despite advances in medical care, HCC treatment remains challenging due to late-stage diagnosis, limited effective therapeutic options, tumor heterogeneity, and drug resistance. MicroRNAs (miRNAs) have attracted substantial attention as key regulators of HCC pathogenesis. These small non-coding RNA molecules play pivotal roles in modulating gene expression, implicated in various cellular processes relevant to cancer development. Understanding the intricate network of miRNA-mediated molecular pathways in HCC is essential for unraveling the complex mechanisms underlying hepatocarcinogenesis and developing novel therapeutic approaches. This manuscript aims to provide a comprehensive review of recent experimental and clinical discoveries regarding the complex role of miRNAs in influencing the key hallmarks of HCC, as well as their promising clinical utility as potential therapeutic targets.

Toxoplasma gondii infection regulates apoptosis of host cells via miR-185/ARAF axis

BACKGROUND

Toxoplasmosis is a zoonosis with a worldwide presence that is caused by the intracellular parasite Toxoplasma gondii. Active regulation of apoptosis is an important immune mechanism by which host cells resist the growth of T. gondii or avoid excessive pathological damage induced by this parasite. Previous studies found that upregulated expression of microRNA-185 (miR-185) during T. gondii infection has a potential role in regulating the expression of the ARAF gene, which is reported to be associated with cell proliferation and apoptosis.

METHODS

The expression levels of miR-185 and the ARAF gene were evaluated by qPCR and Western blot, respectively, in mice tissues, porcine kidney epithelial cells (PK-15) and porcine alveolar macrophages (3D4/21) following infection with the T. gondii ToxoDB#9 and RH strains. The dual luciferase reporter assay was then used to verify the relationship between miR-185 and ARAF targets in PK-15 cells. PK-15 and 3D4/21 cell lines with stable knockout of the ARAF gene were established by CRISPR, and then the apoptosis rates of the cells following T. gondii infection were detected using cell flow cytometry assays. Simultaneously, the activities of cleaved caspase-3, as a key apoptosis executive protein, were detected by Western blot to evaluate the apoptosis levels of cells.

RESULTS

Infection with both the T. gondii ToxoDB#9 and RH strains induced an increased expression of miR-185 and a decreased expression of ARAF in mice tissues, PK-15 and 3D4/21 cells. MiR-185 mimic transfections showed a significantly negative correlation in expression levels between miR-185 and the ARAF gene. The dual luciferase reporter assay confirmed that ARAF was a target of miR-185. Functional investigation revealed that T. gondii infection induced the apoptosis of PK-15 and 3D4/21 cells, which could be inhibited by ARAF knockout or overexpression of miR-185. The expression levels of cleaved caspase-3 protein were significantly lower in cells with ARAF knockout than in normal cells, which were consistent with the results of the cell flow cytometry assays.

CONCLUSIONS

Toxoplasma gondii infection could lead to the upregulation of miR-185 and the downregulation of ARAF, which was not related to the strain of T. gondii and the host cells. Toxoplasma gondii infection could regulate the apoptosis of host cells via the miR-185/ARAF axis, which represents an additional strategy used by T. gondii to counteract host-cell apoptosis in order to maintain survival and reproduce in the host cells.

Ethanolic Extract of Propolis Modulates Autophagy-Related microRNAs in Osteoarthritic Chondrocytes

Osteoarthritis is a multifactorial joint disease characterized by degeneration, and aging stands as a significant risk factor. Autophagy, a crucial cellular homeostasis mechanism, is influenced by aging and closely linked to cartilage health. This correlation between autophagy, cell death, and OA underscores its relevance in disease progression. MicroRNAs have emerged as autophagy regulators, with miRNA-based interventions showing promise in preclinical models. Remarkably, the ethanolic extract of propolis exhibits positive effects on autophagy-related proteins and healthy cartilage markers in an in vitro osteoarthritis model. The aim of this brief report was to evaluate through in silico analysis and postulate five microRNAs that could regulate autophagy proteins (AKT1, ATG5, and LC3) and assess whether the ethanolic extract of propolis could regulate the expression of these microRNAs. Among the examined miRNAs (miR-19a, miR-125b, miR-181a, miR-185, and miR-335), the ethanolic extract of propolis induced significant changes in four of them. Specifically, miR-125b responded to EEP by counteracting IL-1β-induced effects, while miR-181a, miR-185, and miR-335 exhibited distinct patterns of expression under EEP treatment. These findings unveil a potential link between miRNAs, EEP, and autophagy modulation in OA, offering promising therapeutic insights. Nevertheless, further validation and clinical translation are warranted to substantiate these promising observations.

The role of microRNA-185 in the pathogenesis of human diseases: A focus on cancer

MicroRNAs (miRNAs) are a widely-studied class of non-coding RNAs characterized by their short length (18-25 nucleotides). The precise functions of miRNAs are not well-elucidated; however, an increasing number of studies suggest their involvement in various physiologic processes and deregulation in pathologic conditions. miRNA-185 (miR-185) is among the mostly-studied miRNAs in human diseases, which is found to play putative roles in conditions like metabolic disorders, asthma, frailty, schizophrenia, and hepatitis. Notably, many cancer studies report the downregulation of miR-185 in cell lines, tumor tissues, and plasma specimens of patients, while it demonstrates a suppressing role on the malignant properties of cancer cells in vitro and in vivo. Accordingly, miR-185 can be considered a tumor suppressor miRNA in human malignancies, while a few studies also report inconsistent findings. Being suggested as a prognostic/diagnostic biomarker, mi-185 is also found to offer clinical potentials, particularly for early diagnosis and prediction of the prognosis of cancer patients. In this review, we have outlined the studies that have evaluated the functions and clinical significance of miR-185 in different human diseases with a particular focus on cancer.

Tumor Microenvironment Remodeling in Gastrointestinal Cancer: Role of miRNAs as Biomarkers of Tumor Invasion

Gastrointestinal (GI) cancers are the most frequent neoplasm, responsible for half of all cancer-related deaths. Metastasis is the leading cause of death from GI cancer; thus, studying the processes that regulate cancer cell migration is of paramount importance for the development of new therapeutic strategies. In this review, we summarize the mechanisms adopted by cancer cells to promote cell migration and the subsequent metastasis formation by highlighting the key role that tumor microenvironment components play in deregulating cellular pathways involved in these processes. We, therefore, provide an overview of the role of different microRNAs in promoting tumor metastasis and their role as potential biomarkers for the prognosis, monitoring, and diagnosis of GI cancer patients. Finally, we relate the possible use of nutraceuticals as a new strategy for targeting numerous microRNAs and different pathways involved in GI tumor invasiveness.

Epigenetic regulation of autophagy by non-coding RNAs in gastrointestinal tumors: Biological functions and therapeutic perspectives

Cancer is the manifestation of changes and mutations in genetic and epigenetic levels. Non-coding RNAs (ncRNAs) are commonly dysregulated in disease pathogenesis, and their role in cancer has been well-documented. The ncRNAs regulate various molecular pathways and mechanisms in cancer that can lead to induction/inhibition of carcinogenesis. Autophagy is a molecular "self-digestion" mechanism its function can be pro-survival or pro-death in tumor cells. The aim of the present review is to evaluate the role of ncRNAs in regulating autophagy in gastrointestinal tumors. The role of the ncRNA/autophagy axis in affecting the progression of gastric, liver, colorectal, pancreatic, esophageal, and gallbladder cancers is investigated. Both ncRNAs and autophagy mechanisms can function as oncogenic or onco-suppressor and this interaction can determine the growth, invasion, and therapy response of gastrointestinal tumors. ncRNA/autophagy axis can reduce/increase the proliferation of gastrointestinal tumors via the glycolysis mechanism. Furthermore, related molecular pathways of metastasis, such as EMT and MMPs, are affected by the ncRNA/autophagy axis. The response of gastrointestinal tumors to chemotherapy and radiotherapy can be suppressed by pro-survival autophagy, and ncRNAs are essential regulators of this mechanism. miRNAs can regulate related genes and proteins of autophagy, such as ATGs and Beclin-1. Furthermore, lncRNAs and circRNAs down-regulate miRNA expression via sponging to modulate the autophagy mechanism. Moreover, anti-cancer agents can affect the expression level of ncRNAs regulating autophagy in gastrointestinal tumors. Therefore, translating these findings into clinics can improve the prognosis of patients.

HCV Proteins Modulate the Host Cell miRNA Expression Contributing to Hepatitis C Pathogenesis and Hepatocellular Carcinoma Development

Simple Summary

According to the last estimate by the World Health Organization (WHO), more than 71 million individuals have chronic hepatitis C worldwide. The persistence of HCV infection leads to chronic hepatitis, which can evolve into liver cirrhosis and ultimately into hepatocellular carcinoma (HCC). Although the pathogenic mechanisms are not fully understood, it is well established that an interplay between host cell factors, including microRNAs (miRNA), and viral components exist in all the phases of the viral infection and replication. Those interactions establish a complex equilibrium between host cells and HCV and participate in multiple mechanisms characterizing hepatitis C pathogenesis. The present review aims to describe the role of HCV structural and non-structural proteins in the modulation of cellular miRNA during HCV infection and pathogenesis.

Abstract

Hepatitis C virus (HCV) genome encodes for one long polyprotein that is processed by cellular and viral proteases to generate 10 polypeptides. The viral structural proteins include the core protein, and the envelope glycoproteins E1 and E2, present at the surface of HCV particles. Non-structural (NS) proteins consist of NS1, NS2, NS3, NS4A, NS4B, NS5a, and NS5b and have a variable function in HCV RNA replication and particle assembly. Recent findings evidenced the capacity of HCV virus to modulate host cell factors to create a favorable environment for replication. Indeed, increasing evidence has indicated that the presence of HCV is significantly associated with aberrant miRNA expression in host cells, and HCV structural and non-structural proteins may be responsible for these alterations. In this review, we summarize the recent findings on the role of HCV structural and non-structural proteins in the modulation of host cell miRNAs, with a focus on the molecular mechanisms responsible for the cell re-programming involved in viral replication, immune system escape, as well as the oncogenic process. In this regard, structural and non-structural proteins have been shown to modulate the expression of several onco-miRNAs or tumor suppressor miRNAs.

Hepigenetics: A Review of Epigenetic Modulators and Potential Therapies in Hepatocellular Carcinoma

Hepatocellular carcinoma is the fifth most common cancer worldwide and the second most lethal, following lung cancer. Currently applied therapeutic practices rely on surgical resection, chemotherapy and radiotherapy, or a combination thereof. These treatment options are associated with extreme adversities, and risk/benefit ratios do not always work in patients' favor. Anomalies of the epigenome lie at the epicenter of aberrant molecular mechanisms by which the disease develops and progresses. Modulation of these anomalous events poses a promising prospect for alternative treatment options, with an abundance of felicitous results reported in recent years. Herein, the most recent epigenetic modulators in hepatocellular carcinoma are recapitulated on.

Autophagy and Liver Diseases

Autophagy plays an important role in the physiology and pathology of the liver. It is involved in the development of many liver diseases such as α-1-antitrypsin deficiency, chronic hepatitis virus infection, alcoholic liver disease, nonalcoholic fatty liver disease, and liver cancer. Autophagy has thus become a new target for the treatment of liver diseases. How to treat liver diseases by regulating autophagy has been a hot topic.

MicroRNAs Modulate Drug Resistance-Related Mechanisms in Hepatocellular Carcinoma

Primary liver cancer [hepatocellular carcinoma (HCC)] is one of the most common malignant tumors worldwide, causing serious health threats because of its high morbidity and mortality, rapid growth, and strong invasiveness. Patients with HCC frequently develop resistance to the current chemotherapeutic drugs, and this is largely attributed to the high-level heterogeneity of the tumor tissue. MicroRNAs (miRNAs) are a group of master regulators for multiple physiological and pathological processes and play important roles in the tumorigenesis. More recent studies have indicated that miRNAs also play a non-negligible role in the development of drug resistance in liver cancer. In this review, we summarize the data from the latest studies on the mechanisms of drug resistance in liver cancer, including autophagy, membrane transporters, epithelial-mesenchymal transitions (EMTs), tumor microenvironment, and genes and proteins that are associated with apoptosis. The data herein will provide valuable information for the development of novel approaches to tackle drug resistance in the management of liver cancer.

How microRNAs affect the PD-L1 and its synthetic pathway in cancer

Programmed cell death-ligand 1 (PD-L1) is a glycoprotein that is expressed on the cell surface of both hematopoietic and nonhematopoietic cells. PD-L1 play a role in the immune tolerance and protect self-tissues from immune system attack. Dysfunction of this molecule has been highlighted in the pathogenesis of tumors, autoimmunity, and infectious disorders. MicroRNAs (miRNAs) are endogenous molecules that are classified as small non-coding RNA with approximately 20-22 nucleotides (nt) length. The function of miRNAs is based on complementary interactions with target mRNA via matching completely or incompletely. The result of this function is decay of the target mRNA or preventing mRNA translation. In the past decades, several miRNAs have been discovered which play an important role in the regulation of PD-L1 in various malignancies. In this review, we discuss the effect of miRNAs on PD-L1 expression and consider the effect of miRNAs on the synthetic pathway of PD-L1, especially during cancers.

miRNA Regulation of Glutathione Homeostasis in Cancer Initiation, Progression and Therapy Resistance

Glutathione (GSH) is the most abundant antioxidant that contributes to regulating the cellular production of Reactive Oxygen Species (ROS) which, maintained at physiological levels, can exert a function of second messengers in living organisms. In fact, it has been demonstrated that moderate amounts of ROS can activate the signaling pathways involved in cell growth and proliferation, while high levels of ROS induce DNA damage leading to cancer development. Therefore, GSH is a crucial player in the maintenance of redox homeostasis and its metabolism has a role in tumor initiation, progression, and therapy resistance. Our recent studies demonstrated that neuroblastoma cells resistant to etoposide, a common chemotherapeutic drug, show a partial monoallelic deletion of the locus coding for miRNA 15a and 16-1 leading to a loss of these miRNAs and the activation of GSH-dependent responses. Therefore, the aim of this review is to highlight the role of specific miRNAs in the modulation of intracellular GSH levels in order to take into consideration the use of modulators of miRNA expression as a useful strategy to better sensitize tumors to current therapies.

Unmasking the impact of Rictor in cancer: novel insights of mTORC2 complex

Genomic alterations affecting components of the mechanistic target of rapamycin (mTOR) pathway are found rather frequently in cancers, suggesting that aberrant pathway activity is implicated in oncogenesis of different tumor types. mTOR functions as the core catalytic kinase of two distinct complexes, mTOR complex 1 (mTORC1) and 2 (mTORC2), which control numerous vital cellular processes. There is growing evidence indicating that Rictor, an essential subunit of the mTORC2 complex, is inappropriately overexpressed across numerous cancer types and this is associated with poor survival. To date, the candidate mechanisms responsible for aberrant Rictor expression described in cancer are two: (i) gene amplification and (ii) epigenetic regulation, mainly by microRNAs. Moreover, different mTOR-independent Rictor-containing complexes with oncogenic role have been documented, revealing alternative routes of Rictor-driven tumorigenesis, but simultaneously, paving the way for identifying novel biomarkers and therapeutic targets. Here, we review the main preclinical and clinical data regarding the role of Rictor in carcinogenesis and metastatic behavior as well as the potentiality of its alteration as a target.

[MicroRNA-152 and microRNA-448 inhibit proliferation of colorectal cancer cells in vitro by targeting Rictor]

OBJECTIVE

To screen the microRNAs (miRNAs) targeting Rictor and investigate their effects in regulating the biological behaviors of colorectal cancer (CRC).

METHODS

Human colorectal cancer cell line KM12SM was transfected with the miRNAs targeting Rictor identified by prediction software to test inhibitory effects of these miRNAs on Rictor expression using qRT-PCR and Western blotting. Dual luciferase reporter assay was used to further confirm the binding of these miRNAs to the 3'UTR of Rictor mRNA. Cell survival and colony formation assays were used to investigate the effects of these miRNAs on survival and colony formation in KM12SM cells.

RESULTS

miR-152 and miR-448 were identified as the Rictor-targeting miRNAs, which significantly inhibited the expression of Rictor in KM12SM cells (P < 0.05). The two miRNAs were confirmed to bind to the 3'UTR of Rictor mRNA and significantly inhibited luciferase activity in KM12SM cells (P < 0.01, P < 0.05); they also showed activities of posttranscriptional modulation of Rictor. Overexpression of miR-152 and miR-448 both significantly inhibited the growth and colony formation of KM12SM cells.

CONCLUSIONS

miR-152 and miR-448 can down-regulate the protein expression of Rictor by targeting Rictor mRNA to negatively regulate the growth and colony formation of colorectal cancer cells.

Autophagy: Dual Response in the Development of Hepatocellular Carcinoma

Autophagy is an evolutionary conserved intracellular mechanism which helps eukaryotic cells in maintaining their metabolic state to afford high-efficiency energy requirements. In the physiology of a normal liver and the pathogenesis of liver diseases, autophagy plays a crucial role. Autophagy has been found to be both upregulated and downregulated in different cancers providing the evidence that autophagy plays a dual role in suppressing and promoting cell survival. Hepatocellular carcinoma (HCC) is the most common primary liver cancer and the major leading cause of cancer mortality worldwide. In light of its high complexity and poor prognosis, it is essential to improve our understanding of autophagy’s role in HCC. In this review, we summarize the dual mechanism of autophagy in the development of HCC and elucidate the currently used therapeutic strategies for anti-HCC therapy.

MITF-MIR211 axis is a novel autophagy amplifier system during cellular stress

Macroautophagy (autophagy) is an evolutionarily conserved recycling and stress response mechanism. Active at basal levels in eukaryotes, autophagy is upregulated under stress providing cells with building blocks such as amino acids. A lysosome-integrated sensor system composed of RRAG GTPases and MTOR complex 1 (MTORC1) regulates lysosome biogenesis and autophagy in response to amino acid availability. Stress-mediated inhibition of MTORC1 results in the dephosphorylation and nuclear translocation of the TFE/MITF family of transcriptional factors, and triggers an autophagy- and lysosomal-related gene transcription program. The role of family members TFEB and TFE3 have been studied in detail, but the importance of MITF proteins in autophagy regulation is not clear so far. Here we introduce for the first time a specific role for MITF in autophagy control that involves upregulation of MIR211. We show that, under stress conditions including starvation and MTOR inhibition, a MITF-MIR211 axis constitutes a novel feed-forward loop that controls autophagic activity in cells. Direct targeting of the MTORC2 component RICTOR by MIR211 led to the inhibition of the MTORC1 pathway, further stimulating MITF translocation to the nucleus and completing an autophagy amplification loop. In line with a ubiquitous function, MITF and MIR211 were co-expressed in all tested cell lines and human tissues, and the effects on autophagy were observed in a cell-type independent manner. Thus, our study provides direct evidence that MITF has rate-limiting and specific functions in autophagy regulation. Collectively, the MITF-MIR211 axis constitutes a novel and universal autophagy amplification system that sustains autophagic activity under stress conditions. Abbreviations: ACTB: actin beta; AKT: AKT serine/threonine kinase; AKT1S1/PRAS40: AKT1 substrate 1; AMPK: AMP-activated protein kinase; ATG: autophagy-related; BECN1: beclin 1; DEPTOR: DEP domain containing MTOR interacting protein; GABARAP: GABA type A receptor-associated protein; HIF1A: hypoxia inducible factor 1 subunit alpha; LAMP1: lysosomal associated membrane protein 1; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MAPKAP1/SIN1: mitogen-activated protein kinase associated protein 1; MITF: melanogenesis associated transcription factor; MLST8: MTOR associated protein, LST8 homolog; MRE: miRNA response element; MTOR: mechanistic target of rapamycin kinase; MTORC1: MTOR complex 1; MTORC2: MTOR complex 2; PRR5/Protor 1: proline rich 5; PRR5L/Protor 2: proline rich 5 like; RACK1: receptor for activated C kinase 1; RPTOR: regulatory associated protein of MTOR complex 1; RICTOR: RPTOR independent companion of MTOR complex 2; RPS6KB/p70S6K: ribosomal protein S6 kinase; RT-qPCR: quantitative reverse transcription-polymerase chain reaction; SQSTM1: sequestosome 1; STK11/LKB1: serine/threonine kinase 11; TFE3: transcription factor binding to IGHM enhancer 3; TFEB: transcription factor EB; TSC1/2: TSC complex subunit 1/2; ULK1: unc-51 like autophagy activating kinase 1; UVRAG: UV radiation resistance associated; VIM: vimentin; VPS11: VPS11, CORVET/HOPS core subunit; VPS18: VPS18, CORVET/HOPS core subunit; WIPI1: WD repeat domain, phosphoinositide interacting 1.

Prognostic Role of Circulating Exosomal miR-425-3p for the Response of NSCLC to Platinum-Based Chemotherapy

BACKGROUND

Platinum-based doublets with a third-generation agent are the recommended option for many patients with non-small cell lung cancer (NSCLC) with no contraindications to platinum compounds. Unfortunately, the clinical effectiveness of such chemotherapy is limited by intrinsic or acquired resistance.

METHODS

Circulating exosomal miRNAs were isolated and used to perform HiSeq deep-sequencing analyses on serum pool samples from platinum-resistant or platinum-sensitive patients, and six exosomal miRNAs were further validated for their predictive utility by qRT-PCR in 170 serum samples of patients with advanced NSCLC. Gain- and loss-of-function experiments clarified the responsiveness regulating role of the clinically relevant miRNA. IHC analyses were performed to evaluate the association between basal autophagy in lung cancer tissues and responsiveness in 203 patients with NSCLC receiving platinum-based chemotherapy.

RESULTS

Six circulating exosomal miRNAs (miR-425-3p, miR-1273h, miR-4755-5p, miR-9-5p, miR-146a-5p, and miR-215-5p) were found to be differentially expressed with the largest fold change in platinum-resistant patients compared with platinum-sensitive patients. High miR-425-3p proved to be a potent predictive biomarker for low responsiveness and poor progression-free survival (PFS). Mechanistically, miR-425-3p upregulated the autophagic levels via targeting AKT1, leading to the decrease in therapeutic response. Concordantly, high levels of basal autophagy in lung cancer tissues correlate with low responsiveness in patients with NSCLC within the early and advanced disease stages.

CONCLUSIONS

Our study highlights circulating exosomal miR-425-3p as a potential biomarker for improved predictions of the clinical response to platinum-based chemotherapy in patients with NSCLC.

IMPACT

This study provides the first evidence that miR-425-3p in NSCLC patient-derived exosomes can be a marker for predicating the clinical response to platinum-based chemotherapy.

Integrin-β5, a miR-185-targeted gene, promotes hepatocellular carcinoma tumorigenesis by regulating β-catenin stability

Background

The tumour microenvironment is essential for cancer progress and metastasis. Integrin-β5 (ITGB5), a member of the integrin family, has been implicated to mediate the interactions of cells with the extracellular matrix (ECM) and promote tumorigenesis in several malignancies. However, the role of ITGB5 in hepatocellular carcinoma (HCC) is still unknown.

Methods

The biological function of ITGB5 in HCC was investigated using migration, colony formation assays. The potential molecular mechanism of ITGB5 in regulating HCC tumorigenesis and β-catenin stabilization was investigated by western blotting, co-immunoprecipitation and ubiquitination assays. The expression level of ITGB5 mediated by miR-185 was confirmed by bioinformatic analysis, luciferase assay. The clinical significance of ITGB5 was based on human tissue microarray (TMA) analysis.

Results

Here, we found that the expression of ITGB5 is increased in HCC tissues. Elevated ITGB5 markedly facilitates HCC cell migration and tumorigenesis in vitro and in vivo. Further mechanistic studies revealed that ITGB5, as a partner of β-catenin, directly interacts with β-catenin and inhibits its degradation, thus leading to WNT/β-catenin activity. Subsequently, we also found that ITGB5 is a direct targeted gene of miR-185. The downregulation of miR-185 in HCC cells promotes an increase in ITGB5. An additional increase of ITGB5 is associated with β-catenin upregulation and a miR-185 decrease in HCC tissues.

Conclusions

Our data reveal that the miR-185-ITGB5-β-catenin pathway plays an important role in HCC tumorigenesis, and ITGB5 may be a promising specific target for HCC therapy.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0691-9) contains supplementary material, which is available to authorized users.

Octyl gallate reduces ATP levels and Ki67 expression leading HepG2 cells to cell cycle arrest and mitochondria-mediated apoptosis

Octyl gallate (OG) is an antioxidant that has shown anti-tumor, anti-diabetic and anti-amyloidogenic activities. Mitochondria play an important role in hepatocellular carcinoma, mainly by maintaining accelerated cellular proliferation through the production of ATP. Thus, the mitochondria may be a target for antitumor therapies. Here, we investigated the effects of OG in the hepatocarcinoma cell line (HepG2) and the mechanisms involved. We report, for the first time, that treatment with OG for 24h inhibited HepG2 cell growth by decreasing mitochondrial activity and mass, which led to the reduction of ATP levels. This reduction in the energy supply triggered a decrease in Ki67 protein expression, leading cells to cycle arrest. In addition, treatment with two doses of OG for 48h induced loss of mitochondrial functionality, mitochondrial swelling and apoptosis. Finally, we report that HepG2 cells had no resistance to treatment after multiple doses. Collectively, our findings indicate that metabolic dysregulation and Ki67 protein reduction are key events in the initial anti-proliferative action of OG, whereas mitochondrial swelling and apoptosis induction are involved in the action mechanism of OG after prolonged exposure. This suggests that OG targets mitochondria, thus representing a candidate for further research on therapies for hepatocarcinoma.

miR-185 Inhibits Fibrogenic Activation of Hepatic Stellate Cells and Prevents Liver Fibrosis

Recent studies have shown the effect of microRNAs on HSC activation and transformation, which is essential for the pathogenesis of liver fibrosis. In our study, we explored the role of miR-185 in liver fibrosis. Plasma miR-185 was detected in hepatitis B virus-related liver fibrosis patients (S2/3, n = 10) by Illumina HiSeq sequencing, and healthy volunteers were selected (n = 8) as the control group. We found that the plasma miR-185 level in fibrosis patients was significantly downregulated. CCl₄-induced fibrosis tissues in mouse livers and TGF-β1-activated HSCs also presented downregulated miR-185 concomitant with an increased expression of RHEB and RICTOR. To explore the correlations, LX-2 cells were transiently transfected with miR-185 mimics. The expression levels of α-SMA, collagen I, and collagen III were decreased as well as RHEB and RICTOR. Inhibition of endogenous miR-185 increased fibrogenic activity. Furthermore, dual-luciferase reporter assays indicated that miR-185 inhibited the expression of RHEB and RICTOR by directly targeting their 3' UTRs. Moreover, silencing RHEB and RICTOR suppressed α-SMA and collagen expression levels. In conclusion, miR-185 prevents liver fibrogenesis by inhibiting HSC activation via inhibition of RHEB and RICTOR. These results provide new insights into the mechanisms behind the anti-fibrotic effect of miR-185.

Low Frequency Magnetic Fields Induce Autophagy-associated Cell Death in Lung Cancer through miR-486-mediated Inhibition of Akt/mTOR Signaling Pathway

Low frequency magnetic fields (LF-MFs) can affect cell proliferation in a cell-type and intensity-dependent way. Previous study has reported the anti-tumor effect of LF-MFs in lung cancers. Our previous study also optimized the intensity and duration of LF-MFs to effectively inhibit the proliferation of lung cancer cells. However, the anti-tumor mechanism of LF-MFs remains unclear, which limit the clinical application of LF-MFs in anti-tumor therapy. Here, in a well-established Lewis Lung Cancer (LLC) mouse model, we found that LF-MFs inhibit tumor growth and induce an autophagic cell death in lung cancer. We also found that LF-MFs could up-regulate the expression level of miR-486, which was involved in LF-MFs activated cell autophagy. Furthermore, we found B-cell adaptor for phosphatidylinositol 3-kinase (BCAP) is a direct target of miR-486. miR-486 inhibit AKT/mTOR signaling through inhibiting expression of BCAP. Moreover, a decreased expression of miR-486 and an increased expression of BCAP were found in tumor tissues of lung cancer patients. Taken together, this study proved that LF-MFs can inhibit lung cancers through miR-486 induced autophagic cell death, which suggest a clinical application of LF-MFs in cancer treatment.