Autophagy In Hepatocellular Carcinoma Research Articles

A commentary on "Global research status and frontiers on autophagy in hepatocellular carcinoma: A comprehensive bibliometric and visualized analysis".

A commentary on "Global research status and frontiers on autophagy in hepatocellular carcinoma: A comprehensive bibliometric and visualized analysis".

Investigating autophagy and intricate cellular mechanisms in hepatocellular carcinoma: Emphasis on cell death mechanism crosstalk

Hepatocellular carcinoma (HCC) stands as a formidable global health challenge due to its prevalence, marked by high mortality and morbidity rates. This cancer type exhibits a multifaceted etiology, prominently linked to viral infections, non-alcoholic fatty liver disease, and genomic mutations. The inherent heterogeneity of HCC, coupled with its proclivity for developing drug resistance, presents formidable obstacles to effective therapeutic interventions. Autophagy, a fundamental catabolic process, plays a pivotal role in maintaining cellular homeostasis, responding to stressors such as nutrient deprivation. In the context of HCC, tumor cells exploit autophagy, either augmenting or impeding its activity, thereby influencing tumorigenesis. This comprehensive review underscores the dualistic role of autophagy in HCC, acting as both a pro-survival and pro-death mechanism, impacting the trajectory of tumorigenesis. The anti-carcinogenic potential of autophagy is evident in its ability to enhance apoptosis and ferroptosis in HCC cells. Pertinently, dysregulated autophagy fosters drug resistance in the carcinogenic context. Both genomic and epigenetic factors can regulate autophagy in HCC progression. Recognizing the paramount importance of autophagy in HCC progression, this review introduces pharmacological compounds capable of modulating autophagy—either inducing or inhibiting it, as promising avenues in HCC therapy.

Global research status and frontiers on autophagy in hepatocellular carcinoma: a comprehensive bibliometric and visualized analysis.

An extensive body of research has explored the role of autophagy in hepatocellular carcinoma (HCC), revealing its critical involvement in the disease's pathogenesis, progression, and therapeutic targeting. However, there is a discernible deficit in quantitative, analytical studies concerning autophagy in the context of HCC. Accordingly, this investigation endeavored to meticulously assess the evolution of autophagy research, employing bibliometric citation analysis to offer a comprehensive evaluation of the findings in this field. The authors conducted a literature search on 2 August 2023, to extract relevant publications spanning from 2013 to 2022, indexed in the Science Citation Index-Expanded (SCIE) of the Web of Science Core Collection (WOSCC). Subsequently, the authors performed a bibliometric assessment of the compiled documents using visualization tools such as CiteSpace and VOSviewer. The search yielded 734 publications penned by 4699 authors, encompassing contributions from 41 countries and 909 institutions, disseminated across 272 journals, and comprising 26295 co-cited references from 2667 journals. Notably, China led in publication volume with 264 articles (amounting to 35.9%) and exhibited the most robust collaboration with the United States. The mechanisms underlying autophagy's influence on the emergence and advancement of HCC, as well as the implicated proteins and genes, have garnered significant attention. In recent years, investigations of targeting autophagy and the resistance to sorafenib have surfaced as pivotal themes and emerging frontiers in this domain. This study rigorously collated and distilled the prevailing research narratives and novel insights on autophagy in HCC. The resultant synthesis provides a substantive foundation for medical professionals and researchers, as well as pivotal implications for future investigative endeavors in this arena.

Unraveling the Janus-Faced Role of Autophagy in Hepatocellular Carcinoma: Implications for Therapeutic Interventions.

This review aims to provide a comprehensive understanding of the molecular mechanisms underlying autophagy and mitophagy in hepatocellular carcinoma (HCC). Autophagy is an essential cellular process in maintaining cell homeostasis. Still, its dysregulation is associated with the development of liver diseases, including HCC, which is one of leading causes of cancer-related death worldwide. We focus on elucidating the dual role of autophagy in HCC, both in tumor initiation and progression, and highlighting the complex nature involved in the disease. In addition, we present a detailed analysis of a small subset of autophagy- and mitophagy-related molecules, revealing their specific functions during tumorigenesis and the progression of HCC cells. By understanding these mechanisms, we aim to provide valuable insights into potential therapeutic strategies to manipulate autophagy effectively. The goal is to improve the therapeutic response of liver cancer cells and overcome drug resistance, providing new avenues for improved treatment options for HCC patients. Overall, this review serves as a valuable resource for researchers and clinicians interested in the complex role of autophagy in HCC and its potential as a target for innovative therapies aimed to combat this devastating disease.

Targeting SIRT1 synergistically improves the antitumor effect of JQ-1 in hepatocellular carcinoma

Bromodomain and extraterminal domain protein inhibitors have shown therapeutic promise in hepatocellular carcinoma. However, resistance to bromodomain and extraterminal domain protein inhibitors has emerged in preclinical trials, presenting an immense clinical challenge, and the mechanisms are unclear. In this study, we found that overexpression of SIRT1 induced by JQ-1, a bromodomain and extraterminal domain protein inhibitor, may confer resistance to JQ-1 in hepatocellular carcinoma. SIRT1 protein expression was higher in hepatocellular carcinoma tissues than in normal tissues, and this phenotype was correlated with a poor prognosis. Cotreatment with JQ-1 and the SIRT1 inhibitor EX527 synergistically suppressed proliferation and blocked cell cycle progression in hepatocellular carcinoma cells. Combined administration of JQ-1 and EX527 successfully reduced the tumor burden in vivo. In addition, JQ-1 mediated AMPK/p-AMPK axis activation to upregulate SIRT1 protein expression and enhanced autophagy to inhibit cell apoptosis. Activation of AMPK could alleviate the antitumor effect of the combination of JQ-1 and EX527 on hepatocellular carcinoma cells. Furthermore, inhibition of SIRT1 further enhanced the antitumor effect of JQ-1 by blocking protective autophagy in hepatocellular carcinoma. Our study proposes a novel and efficacious therapeutic strategy of a BET inhibitor combined with a SIRT1 inhibitor for hepatocellular carcinoma.

Potential of curcumin and niacin-loaded targeted chitosan coated liposomes to activate autophagy in hepatocellular carcinoma cells: An in vitro evaluation in HePG2 cell line

The objective of this study is to activate autophagy in hepatocellular carcinoma for the enhancement of its cellular degradation. Liposomes incorporated chitosan in the core used to improve the stability of lecithin and increase the niacin loading efficiency. Additionally, curcumin as a hydrophobic molecule entrapped into liposomal layers and used as a face layer to minimize the release of niacin in physiological pH 7.4. Folic acid-conjugated chitosan was used to facilitate the delivery of liposomes into a specific location of cancer cells. TEM, UV Visible spectrophotometer, and FTIR confirmed the successful liposomal formation and good encapsulation efficiency. Based on the cellular proliferation of HePG2, the results revealed that there was a significant inhibition of growth rate of HePG2 after 48 h of incubation at a concentration of 100 μg/mL by 91 % ± 1 %, P ≤ 0.002 (pure niacin), 55 % ± 3 %, P ≤ 0.001 (pure curcumin), 83 % ± 1.5 %, P ≤ 0.001 (niacin NPs), and 51 % ± 1.5 % P ≤ 0.0001 (curcumin-niacin NPs) of relative to the control. Increasingly, The expression of mRNA of mTOR was significantly increased by 0.72 ± 0.08 P ≤ 0.001, 1 ± 0.1, 0. P ≤ 0.001, 5 ± 0.07 P ≤ 0.01, and 1.3 ± 0.02 P ≤ 0.001 folds) in pure niacin, pure curcumin, niacin NPs and curcumin -niacin NPs, respectively, relative to the control with an expression of 0.3 ± 0.08. Additionally, the expression of p62 mRNA was significantly increased by 0.92 ± 0.07 P ≤ 0.05, 1.7 ± 0.07 P ≤ 0.0001, 0.72 ± 0.08 P ≤ 0.5, and 2.1 ± 0.1 P ≤ 0.0001 folds relative to that of the control with an expression of 0.72 ± 0.08. The results highlight the efficient therapies of biomaterials derived from natural sources that can be used in cancer therapies instead of traditional chemotherapies.

Overexpression of the lncRNA HOTAIRM1 promotes lenvatinib resistance by downregulating miR-34a and activating autophagy in hepatocellular carcinoma

BackgroundHepatocellular carcinoma (HCC) is one of the most common malignant cancers in humans and has a high fatality rate. Despite pharmacological advances such as sorafenib and lenvatinib approval, responses are seen only in a limited fraction of HCCs, and the majority of HCC patients do not benefit from this treatment. In recent years, researchers have verified that the long noncoding RNAs (lncRNAs) impact the efficiency of lenvatinib and the prognosis of patients with HCC.Materials and methodsThis work obtained gene expression profile from an Arraystar lncRNA microarray. Expression of HOTAIRM1, Beclin-1, and p62 in HCC was characterized in clinical HCC tissues of 24 patients with HCC. Overexpression and knockdown experiments were performed in HCC cells to examine the effects of the HOTAIRM1 on lenvatinib sensitivity. The interactions between HOTAIRM1, miR-34a and Beclin-1 were predicted according to GSEA and CNC network. The effects of HOTAIRM1, autophagy and lenvatinib on tumor inhibit were validated in orthotopic tumor-bearing nude mouse model.ResultsLenvatinib-resistant HCC cell lines were established using the concentration gradient method. Data from an Arraystar lncRNA microarray indicated that HOTAIRM1, a specific lncRNA located in an evolutionarily highly conserved HOX gene cluster, was differentially expressed between lenvatinib-resistant HCC cells and their parental cells. Expression of HOTAIRM1 and Beclin-1 in HCC was characterized in clinical HCC tissues of 24 patients who have different sensitivity to lenvatinib. Knocking down of HOTAIRM1 decreased the autophagy level in lenvatinib-resistant HCC cells and increased their sensitivity to lenvatinib, especially when combined with autophagy inhibitors both in vitro and in vivo. Further study indicated that knocking down HOTAIRM1 in lenvatinib-resistant cell lines increased the level of miR-34a and inhibited the expression of Beclin-1 in Huh7-R and HepG2-R cells. Investigation according to GSEA and CNC network, lncRNA and nearby coding gene and lncRNA-miRNA analyses demonstrated that the resistance of HCC to lenvatinib was affected by the HOTAIRM1-miR-34a-Beclin-1 regulatory axis.ConclusionHOTAIRM1 is an independent drug resistance factor which significantly associated with the efficacy of lenvatinib in HCC. HOTAIRM1 may downregulation of miR-34a and upregulation of Beclin-1, leading to activation of autophagy, thereby inducing lenvatinib resistance in HCC.

A PTEN-Autophagy Risk Model for the Prediction of Prognosis and Immune Microenvironment in Hepatocellular Carcinoma.

The clinical behavior and molecular mechanisms of hepatocellular carcinoma (HCC) are complex and highly variable, limiting the discovery of new targets and therapies in clinical research. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is one of the tumor suppressor genes. It is of great interest to discover the role of unexplored correlation among PTEN, the tumor immune microenvironment, and autophagy-related signaling pathways and to construct a reliable risk model for prognosis during HCC progression. We first performed differential expression analysis on the HCC samples. By using Cox regression and LASSO analysis, we determined the DEGs contributing to the survival benefit. In addition, the gene set enrichment analysis (GSEA) was performed to identify potential molecular signaling pathways regulated by the PTEN gene signature, autophagy, and autophagy-related pathways. ESTIMATE was also employed for evaluating the composition of immune cell populations. We found a significant correlation between PTEN expression and the tumor immune microenvironment. The low-PTEN expression group had higher immune infiltration and lower expression of immune checkpoints. In addition, PTEN expression was found to be positively correlated with autophagy-related pathways. Then, differentially expressed genes between tumor and tumor-adjacent samples were screened, and 2895 genes were significantly associated with both PTEN and autophagy. Based on PTEN-related genes, we identified 5 key prognostic genes, including BFSP1, PPAT, EIF5B, ASF1A, and GNA14. The 5-gene PTEN-autophagy risk score (RS) model was demonstrated to have favorable performance in the prediction of prognosis. In summary, our study showed the importance of the PTEN gene and its correlation with immunity and autophagy in HCC. The PTEN-autophagy.RS model we established could be used to predict the prognosis of HCC patients and showed significantly higher prognostic accuracy than the TIDE score in response to immunotherapy.

Oncogenic lncRNA BBOX1-AS1 promotes PHF8-mediated autophagy and elicits sorafenib resistance in hepatocellular carcinoma

Some long non-coding RNAs (lncRNAs) have been documented to be involved in cancer progression and anticancer drug resistance in hepatocellular carcinoma (HCC). Thus, approaches designed to target these genes may facilitate the development of promising strategies for treating HCC. Previously, we showed that lncRNA BBOX1-AS1 was highly expressed and played an oncogenic role in HCC. However, the potential functions and mechanisms through which BBOX1-AS1 regulates HCC progression and drug resistance remain unclear. This study revealed that BBOX1-AS1 could promote tumor progression, autophagy, and drug resistance by upregulating PHF8 in HCC cells. Mechanistically, BBOX1-AS1 enhanced the stability of PHF8 mRNA by targeting the PHF8 inhibitor miR-361-3p to regulate tumor progression and autophagy in HCC. The functional rescue experiments showed that PHF8 acted as a key factor in regulating the biological effects induced by BBOX1-AS1 and miR-361-3p in HCC, indicating that BBOX1-AS1 promotes tumor progression and sorafenib resistance by regulating miR-361-3p/PHF8. Finally, mouse tumor models and patient-derived organoid models were established to further confirm these findings. Taken together, the results demonstrate that BBOX1-AS1 promotes HCC progression and sorafenib resistance via the miR-361-3p/PHF8 axis.

Hugan Buzure Induces Autophagy and Apoptosis in Hepatocellular Carcinoma by Inhibiting PI3K/Akt/mTOR Signaling Pathway

This study explored the effects of Hugan Buzure (HBR) on cell apoptosis and autophagy in hepatocellular carcinoma (HCC) and the molecular mechanisms of the PI3K/Akt/mTOR signaling pathway. HepG2 and Huh7 cell viability was detected by the tetramethylazolium salt colorimetric (MTT) method. Cell proliferation was measured using the colony formation method. Hoechst 33258 staining and flow cytometry were employed to detect apoptosis. In addition, immunofluorescence was carried out to evaluate the expression of LC3. Western blot was performed to detect the expression of Bcl-2, Bax, Caspase-3, LC3, Beclin1, p62 (SQSTM1), and PI3K/Akt/mTOR signal pathway-related proteins in HCC cells. This work verified that HBR reduced HepG2 and Huh7 cell proliferation in a concentration-dependent manner. Treatment with HBR caused an obvious improvement of the apoptosis rate, accompanied by the increase in Bax/Bcl2, Caspase3, LC3II, and Beclin1 levels, respectively. Furthermore, HBR downregulated the expression of p62, p-PI3K, p-Akt, and p-mTOR proteins. HBR combined with HCQ enhanced HBR-induced apoptosis. In conclusion, HBR induced autophagy and apoptosis through PI3K/Akt/mTOR signaling pathway, leading to HCC cell death. This research preliminarily suggested the potential role of HBR in the treatment of HCC.

A novel risk signature based on autophagy-related genes to evaluate tumor immune microenvironment and predict prognosis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is considered a lethal disease due to the poor prognosis and the limited therapeutic efficacy. Much more attention is being attached to the role of autophagy in HCC, and the relationship between autophagy and tumor immune microenvironment. Therefore, we developed a novel prognostic risk signature based on autophagy-related genes (ARGs) for HCC patients using gene expression profiles collected from TCGA dataset. This 2-ARG-based signature (BIRC5 and SNRPB) was validated in ICGC and GSE14520 datasets, achieving a favorable performance in both overall survival and recurrence-free survival outcomes. Additionally, the autophagy gene signature could independently predict overall survival of HCC after adjusting clinicopathological indicators in three independent datasets. A nomogram including autophagy gene signature and TNM stage was built to serve clinical practice. Significantly, differential abundance of immune cells was shown in different risk groups and the critical immune checkpoints and immunosuppressive cytokines were upregulated in the autophagy high-risk group. Furthermore, the expression levels of proteins encoded by BIRC5 and SNRPB were validated in cell lines by western blot and in tissue samples by immunohistochemistry. In summary, the 2-ARG-based prognostic risk signature could be a useful tool to identify risk subgroups, evaluate immune microenvironment and provide therapeutic targets for HCC patients.

Metabolite Profiling of Alocasia gigantea Leaf Extract and Its Potential Anticancer Effect through Autophagy in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a poor-prognosis type of cancer with high resistance to chemotherapy, making the search for safe drugs a mandatory issue. Plant-derived products have potential to reduce negative side effects of cancer treatments. In this work, ability of a defatted methanolic extract of Alocasia gigantea leaves to fight HCC was evaluated in an animal model. Overall, treatment of HCC-induced mice with the methanolic extract at 150 mg/kg body weight for four consecutive weeks caused induction of autophagy through silencing of the relative expression of autophagy suppressor (mTOR) and inducement of autophagy markers (AMPK, Beclin-1, and LC-3). Moreover, it improved preservation of the hepatic histological architecture of the animals, with minor hepatocytic changes but scattered foci of hepatocytic apoptosis. Chemical profiling of the methanolic extract via ultra-high-performance liquid chromatography coupled to a diode array detector and an electrospray mass spectrometer (UHPLC-DAD-ESI-MS/MS) allowed identification of di-C-glycosyl flavones, mostly represented by 6-C-hexosyl-8-C-pentosyl apigenin isomers, which may possibly be associated with inducement of the autophagy pathway in HCC. Overall, these outcomes gave an initial visualization of the operative effect of some compounds in A. gigantea leaves that are potential treatment for HCC.

ARFIP2 Regulates EMT and Autophagy in Hepatocellular Carcinoma in Part Through the PI3K/Akt Signalling Pathway.

ARFIP2, a canonical BAR domain-containing protein, is closely associated with regulating cargo exit from the Golgi. However, the potential biological functions of ARFIP2 in hepatocellular carcinoma (HCC) have not been well investigated. This study aimed to explore the critical role of ARFIP2 in HCC cells. The expression of proteins related to epithelial to mesenchymal transition (EMT) and cell autophagy in HCC cells and tissues was assayed by quantitative real-time PCR, Western blotting, immunohistochemistry and immunofluorescence staining. The ability of cells to proliferate, migrate and invade was detected by Cell Counting Kit-8, Transwell migration and invasion assays. In addition, the function of ARFIP2 in vivo was assessed using a tumour xenograft model. ARFIP2 expression is significantly upregulated in early recurrent and metastatic HCC patients and was positively correlated with a poor prognosis. ARFIP2 overexpression promoted cell proliferation, migration, and invasion by inducing EMT and inhibiting autophagy in vitro. Furthermore, the regulatory effects of ARFIP2 on autophagy and EMT were partially attributed to its regulation of the PI3K/AKT signalling pathway. The in vivo results also showed that ARFIP2 modulates HCC progression. Our results substantiate a novel mechanism by which ARFIP2 can regulate the activity/phosphorylation of Akt to promote EMT and inhibit autophagy in part via the PI3K/Akt signalling pathway. The ARFIP2/PI3K/Akt axis may be a potential diagnostic biomarker and therapeutic target for HCC.

Developing and Validating an Autophagy Gene-Set-Based Prognostic Signature in Hepatocellular Carcinoma Patients.

Hepatocellular carcinoma (HCC), a major type of cancer affecting the lives of people across the world, is one of many diseases whose advancement is thought to be influenced by autophagy dysfunction. Here, the prognostic significance of autophagy in HCC will be investigated. The Cancer Genome Atlas (TCGA) database was employed in this work to identify 62 differentially-expressed Autophagy-Related Genes (ARGs) in HCC patients. Functional enrichment studies revealed that autophagy played a tumor-promoting role in the advancement of HCC. Based on RNA sequencing of 116 tumor samples and 114 paracancerous tissue samples acquired from HCC patients at the Guangxi Medical University Cancer Hospital, 866 differentially expressed prognosis-related genes were identified. Using lasso regression analysis, two ARGs (BIRC5 and BAK1) linked to prognosis were discovered after intersecting the differential genes derived from the prognosis-related groups. A risk score based on ARGs was developed using a Cox proportional hazards regression model. RNA sequencing data were used to construct this model. Finally, the TCGA and The Human Protein Atlas Databases (THPA) were used to validate the clinical data of 116 HCC patients. Elevated expression level of the BAK1 and BIRC5 genes is linked to poor prognosis. The two ARGs were used to calculate the risk score as follows: (0.0253*BAK1) + (0.0051*BIRC5). Risk score served as the independent prognostic factor as per the multivariate analysis. TCGA, THPA, and data from the Guangxi Medical University Cancer Hospital were used to confirm the predictive validity of risk scores for the prognosis of HCC patients. This study offers molecular insights regarding the involvement of autophagy in HCC patients, along with a probable prognostic signature for determining the outcome (prognosis) of HCC patients.

Isoginkgetin, a potential CDK6 inhibitor, suppresses SLC2A1/GLUT1 enhancer activity to induce AMPK-ULK1-mediated cytotoxic autophagy in hepatocellular carcinoma

ABSTRACT Isoginkgetin (ISO), a natural biflavonoid, exhibited cytotoxic activity against several types of cancer cells. However, its effects on hepatocellular carcinoma (HCC) cells and mechanism remain unclear. Here, we revealed that ISO effectively inhibited HCC cell proliferation and migration in vitro. LC3-II expression and autophagosomes were increased under ISO treatment. In addition, ISO-induced cell death was attenuated by treatment with chloroquine or knockdown of autophagy-related genes (ATG5 or ULK1). ISO significantly suppressed SLC2A1/GLUT1 (solute carrier family 2 member 1) expression and glucose uptake, leading to activation of the AMPK-ULK1 axis in HepG2 cells. Overexpression of SLC2A1/GLUT1 abrogated ISO-induced autophagy. Combining molecular docking with thermal shift analysis, we confirmed that ISO directly bound to the N terminus of CDK6 (cyclin-dependent kinase 6) and promoted its degradation. Overexpression of CDK6 abrogated ISO-induced inhibition of SLC2A1/GLUT1 transcription and induction of autophagy. Furthermore, ISO treatment significantly decreased the H3K27ac, H4K8ac and H3K4me1 levels on the SLC2A1/GLUT1 enhancer in HepG2 cells. Finally, ISO suppressed the hepatocarcinogenesis in the HepG2 xenograft mice and the diethylnitrosamine+carbon tetrachloride (DEN+CCl4)-induced primary HCC mice and we confirmed SLC2A1/GLUT1 and CDK6 as promising oncogenes in HCC by analysis of TCGA data and human HCC tissues. Our results provide a new molecular mechanism by which ISO treatment or CDK6 deletion promotes autophagy; that is, ISO targeting the N terminus of CDK6 for degradation inhibits the expression of SLC2A1/GLUT1 by decreasing the enhancer activity of SLC2A1/GLUT1, resulting in decreased glucose levels and inducing the AMPK-ULK1 pathway.

The inhibition of autophagy by spautin boosts the anticancer activity of fingolimod in multidrug-resistant hepatocellular carcinoma

The contribution of autophagy to drug resistance has been studied in several cancers. However, there is no clear evidence about the role of autophagy in the resistance to chemotherapy in cancers, such as hepatocellular carcinoma (HCC). HCC is characterized by a poor prognosis and limited therapeutic options. Moreover, the emergence of multidrug-resistance (MDR) hinders successful treatment. Therefore, understanding how autophagy is regulated in resistant HCC is essential for sensitizing this malignancy to chemotherapy. This work demonstrated that basal and induced autophagy differ between parental and resistant Hep3B cells. In optimum growth conditions, the basal level of autophagy was low in resistant Hep3B (Hep3B-R) cells compared to the wild-type Hep3B (Hep3B-P) cells. However, in metabolic or therapeutic stress conditions, the rate of autophagy flux was much faster in the resistant cells. The work also confirmed the pro-survival function of autophagy in HCC. Besides, it demonstrated that the autophagy inhibitor, spautin, acted synergistically with fingolimod (FTY720) to promote cell death. The combination treatment resulted in superior reactive oxygen species (ROS) production and significant induction of apoptosis. In addition, spautin potentiated the effect of FTY720 against cell survival pathways like the Akt and ERK. Interestingly, the results indicated that Hep3B-R cells were more sensitive to autophagy inhibition than their parental counterparts. Collectively, this work revealed that combining spautin with chemotherapeutic agents that induce cytoprotective autophagy such as FTY720 is a promising approach to overcome MDR in HCC.

Hu Antigen R (HuR) Protein Structure, Function and Regulation in Hepatobiliary Tumors.

Simple SummaryHepatobiliary tumors are a group of primary malignancies encompassing the liver, the intra- and extra-hepatic biliary tracts, and the gall bladder. Within the liver, hepatocellular carcinoma (HCC) is the most common type of primary cancer, which is, also, representing the third-most recurrent cause of cancer-associated death and the sixth-most prevalent type of tumor worldwide, nowadays. Although less frequent, cholangiocarcinoma (CCA) is, currently, a fatal cancer with limited therapeutic options. Here, we review the regulatory role of Hu antigen R (HuR), a ubiquitous member of the ELAV/Hu family of RNA-binding proteins (RBPs), in the pathogenesis, progression, and treatment of HCC and CCA. Overall, HuR is proposed as a valuable diagnostic and prognostic marker, as well as a therapeutic target in hepatobiliary cancers. Therefore, novel therapeutic approaches that can selectively modulate HuR function appear to be highly attractive for the clinical management of these types of tumors.Hu antigen R (HuR) is a 36-kDa ubiquitous member of the ELAV/Hu family of RNA-binding proteins (RBPs), which plays an important role as a post-transcriptional regulator of specific RNAs under physiological and pathological conditions, including cancer. Herein, we review HuR protein structure, function, and its regulation, as well as its implications in the pathogenesis, progression, and treatment of hepatobiliary cancers. In particular, we focus on hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), tumors where the increased cytoplasmic localization of HuR and activity are proposed, as valuable diagnostic and prognostic markers. An overview of the main regulatory axes involving HuR, which are associated with cell proliferation, invasion, metastasis, apoptosis, and autophagy in HCC, is provided. These include the transcriptional, post-transcriptional, and post-translational modulators of HuR function, in addition to HuR target transcripts. Finally, whereas studies addressing the relevance of targeting HuR in CCA are limited, in the past few years, HuR has emerged as a potential therapeutic target in HCC. In fact, the therapeutic efficacy of some pharmacological inhibitors of HuR has been evaluated, in early experimental models of HCC. We, further, discuss the major findings and future perspectives of therapeutic approaches that specifically block HuR interactions, either with post-translational modifiers or cognate transcripts in hepatobiliary cancers.

Shikonin induces apoptosis and autophagy via downregulation of pyrroline-5-carboxylate reductase1 in hepatocellular carcinoma cells

ABSTRACT Shikonin(SK) is a natural small molecule naphthoquinone compound, which has anti-cancer activity in various human malignant tumors. Pyrroline-5-carboxylate reductase 1(PYCR1) is involved in tumorigenesis and regulates various cellular processes, including growth, invasion, migration, and apoptosis. However, the effect of SK and PYCR1 on apoptosis and autophagy in hepatocellular carcinoma are unclear. Our goal is to determine the internal molecular mechanism of the interaction between SK and PYCR1 and its role in the occurrence and development of liver cancer. The CCK8 assay, wound healing assay, and transwell assays show that SK and siPYCR1(gene silence PYCR1) inhibited the malignant phenotype of HCC cells, including cell viability, colony formation, migration, and invasion, respectively. The flow cytometry assays and immunofluorescence show that SK and siPYCR1 activated apoptosis and autophagy, respectively. SK induces apoptosis and autophagy in a dose-dependent manner. In addition, HCC cells were transfected with small interference fragment PYCR1 siRNA to construct siPYCR1 and SK single treatment group and co-treatment group to verify the interaction between SK and PYCR1. The Western blot identified that PI3K/Akt/mTOR signal pathway protein expression was significantly downregulated in HCC cells treated with SK and siPYCR1 together. Collectively, SK may induce apoptosis and autophagy by reducing the expression of PYCR1 and suppressing PI3K/Akt/mTOR. Thus, SK may be a promising antineoplastic drug in Hepatocellular carcinoma (HCC). SK downregulating PYCR1 might supply a theoretical foundation for the potential therapeutic application in hepatocellular carcinoma.

Indole Hydrazide Compound IHZ-1 Induces Apoptosis and Autophagy via Activation of ROS/JNK Pathway in Hepatocellular Carcinoma.

Hepatocellular carcinoma is one of the most common primary malignant tumors of the digestive system. Compound 5-chloro-N′-(2,4-dimethoxybenzylidene)-1H-indole-2-carbohydrazide (IHZ-1/ZJQ-24) is a novel indole hydrazide derivative. In a recent study, we demonstrated that IHZ-1 inhibits tumor growth and induces cell apoptosis through inhibiting the kinase activity of mTORC1 without activation of AKT, which is associated with JNK/IRS-1 activation. However, the impact and mechanisms of JNK activation by IHZ-1 in hepatocellular carcinoma remains entirely unknown. Here, we find that IHZ-1 increases the generation of intracellular ROS and enhances autophagy. The phosphorylation of JNK induced by IHZ-1 was reversed by the decreased ROS level. Moreover, inhibition of ROS/JNK or autophagy equally attenuated apoptotic effect induced by IHZ-1. Our findings suggest that the activation of JNK by IHZ-1 treatment is dependent on the generation of ROS that mediates apoptosis and autophagy in hepatocellular carcinoma.

Tumor treating fields (TTFields) in combination with sorafenib inhibit hepatocellular carcinoma in vitro and in vivo.

464 Background: Hepatocellular carcinoma (HCC) is a highly malignant liver cancer and a leading cause of cancer related mortality. Sorafenib was the first approved systemic treatment for HCC, and remains one of few front-line treatments for this malignancy. Tumor treating fields (TTFields) are low intensity (1-3 V/cm), intermediate frequency (100-500 kHz), alternating electric fields that exert antimitotic effects on cancerous cells. Results of the phase 2 HEPANOVA study of TTFields (150 kHz) plus sorafenib for advanced HCC support investigation of TTFields in a randomized controlled phase 3 study. The current research aimed to describe the in vitro and in vivo efficacy of this combination and to elucidate details regarding the underlying mechanism of action. Methods: In vitro examinations were performed in HepG2 and Huh-7D12 human HCC cell lines, to which TTFields at a frequency of 150 kHz were applied using the inovitro system. Autophagy was examined by western blot and fluorescence detection of microtubule-associated protein light chain 3 (LC3) levels, an accepted autophagy marker. The effect of TTFields in combination with sorafenib was evaluated using cytotoxic, clonogenic, and apoptotic assays. In vivo, SD rats were inoculated orthotopically into the left hepatic lobe with N1S1 HCC cells. 7 days later, TTFields or sham (heat) were applied to the abdominal region of the rats, continuously for 6 days. Daily intraperitoneal injections of sorafenib (10 mg/kg/day) or vehicle were performed during this time. To determine tumor volume growth, MRI images were acquired before and after treatment. Levels of autophagy and apoptosis were examined in tumor sections by immunohistochemistry for LC3 and cleaved PARP, respectively. Results: Application of TTFields induced autophagy in HCC cells. TTFields delivery was cytotoxic to the cells, reduced their colony forming ability, and induced apoptosis while combination with sorafenib elevated these effects. In vivo, tumor volume increased 6-fold in control animals vs 1.6-fold in animals treated with TTFields plus sorafenib. This effect was accompanied by significantly elevated levels of cleaved PARP and LC3 within the tumors of treated relative to control rats. Conclusions: The results demonstrate induction of autophagy and apoptosis in HCC following treatment with TTFields. Concomitant application of TTFields with sorafenib enhanced efficacy via a mechanism that may involve overwhelming autophagy, in vitro and in vivo.