Induction of Bcl-2 expression by hepatitis B virus pre-S2 mutant large surface protein resistance to 5-fluorouracil treatment in Huh-7 cells

Hepatitis B Surface Antigen Isoforms: Their Clinical Implications, Utilisation in Diagnosis, Prevention and New Antiviral Strategies

The hepatitis B surface antigen (HBsAg) is a multifunctional glycoprotein composed of large (LHB), middle (MHB), and small (SHB) subunits. HBsAg isoforms have numerous biological functions during HBV infection-from initial and specific viral attachment to the hepatocytes to initiating chronic infection with their immunomodulatory properties. The genetic variability of HBsAg isoforms may play a role in several HBV-related liver phases and clinical manifestations, from occult hepatitis and viral reactivation upon immunosuppression to fulminant hepatitis and hepatocellular carcinoma (HCC). Their immunogenic properties make them a major target for developing HBV vaccines, and in recent years they have been recognised as valuable targets for new therapeutic approaches. Initial research has already shown promising results in utilising HBsAg isoforms instead of quantitative HBsAg for correctly evaluating chronic infection phases and predicting functional cures. The ratio between surface components was shown to indicate specific outcomes of HBV and HDV infections. Thus, besides traditional HBsAg detection and quantitation, HBsAg isoform quantitation can become a useful non-invasive biomarker for assessing chronically infected patients. This review summarises the current knowledge of HBsAg isoforms, their potential usefulness and aspects deserving further research.

Development and cytotoxicity evaluation of multiple nanoemulsions for oral co-delivery of 5-fluorouracil and short chain triglycerides for colorectal cancer

Colorectal cancer (CRC) is the third most common cancer in the world, but current chemotherapy options are limited due to adverse effects and low oral bioavailability of drugs. In this study, we investigated the obtainment parameters and composition of new multiple nanoemulsions (MN) based on microemulsions for oral co-delivery of 5-fluorouracil (5FU) and short-chain triglycerides (SCT, either tributyrin or tripropionin). The area of microemulsion formation was increased from 14% to 38% when monocaprylin was mixed with tricaprylin as oil phase. Addition of SCT reduced this value to 24-26%. Using sodium alginate aqueous dispersion as internal aqueous phase (to avoid phase inversion) did not further affected the area but increased microemulsion viscosity by 1.5-fold. To obtain the MN, selected microemulsions were diluted in an external aqueous phase; droplet size was 500 nm and stability improved using polyoxyethylene (den Besten et al., 2013) oleyl ether at 1-2.5% as surfactant in the external phase and a dilution ratio of 1:1 (v/v). 5FU in vitro release could be better described by the Korsmeyer-Peppas model. No pronounced changes in droplet size were observed when selected MNs were incubated in buffers mimicking gastrointestinal fluids. The 5FU cytotoxicity in monolayer cell lines presenting various mutations was influenced by its incorporation in the nanocarrier, presence of SCT and cell mutation status. The MNs selected reduced the viability of tumor spheroids (employed as 3D tumor models) by 2.2-fold compared to 5FU solution and did not affect the survival of the G. mellonella, suggesting effectiveness and safety.

Chemical-induced degradation of PreS2 mutant surface antigen via the induction of microautophagy

Naturally evolved immune-escape PreS2 mutant is an oncogenic caveat of liver cirrhosis and hepatocellular carcinoma (HCC) during chronic hepatitis B virus (HBV) infection. PreS2 mutant is prevalent in above 50% of patients with HCC. In addition, intrahepatic expression of PreS2 mutant large surface antigen (PreS2-LHBS) induces endoplasmic reticulum stress, mitochondria dysfunction, cytokinesis failure, and subsequent chromosome hyperploidy. As PreS2-LHBS has no enzymatic activity, the development of PreS2-specific inhibitors can be challenging. In this study, we aim to identify inhibitors of PreS2-LHBS via the induction of protein-specific degradation. We set up a large-scale protein stability reporter platform and applied an FDA-approved drug library for the screening. We identified ABT199 as a negative modulator of PreS2-LHBS, which induced the degradation of PreS2-LHBS without affecting the general cell viability in both hepatoma and immortalized hepatocytes. Next, by affinity purification screening, we found that PreS2-LHBS interacted with HSC70, a microautophagy mediating chaperone. Simultaneously, inhibitions of lysosomal degradation or microautophagy restored the expression of PreS2-LHBS, suggesting microautophagy is involved in ABT199-induced PreS2-LHBS degradation. Notably, a 24-hr treatment of ABT199 was sufficient for the reduction of DNA damage and cytokinesis failure in PreS2-LHBS expressing hepatocytes. In addition, a persistent treatment of ABT199 for 3 weeks reversed chromosome hyperploidy in PreS2-LHBS cells and suppressed anchorage-independent growth of HBV-positive hepatoma cells. Together, this study identified ABT-199 as a negative modulator of PreS2-LHBS via mediating microautophagy. Our results indicated that long-term inhibition of PreS2-LHBS may serve as a novel strategy for the therapeutic prevention of HBV-mediated HCC.

Association of Increased Programmed Death Ligand 1 Expression and Regulatory T Cells Infiltration with Higher Hepatocellular Carcinoma Recurrence in Patients with Hepatitis B Virus Pre-S2 Mutant after Curative Surgical Resection

Although surgical resection is available as a potentially curative therapy for hepatocellular carcinoma (HCC), high recurrence of HCC after surgery remains a serious obstacle for long-term patient survival. Therefore, the discovery of valuable prognostic biomarkers for HCC recurrence is urgently needed. Pre-S2 mutant is a mutant form of hepatitis B virus (HBV) large surface protein which is expressed from the HBV surface gene harboring deletion mutations spanning the pre-S2 gene segment. Pre-S2 mutant-positive HCC patients have been regarded as a high-risk population of HCC recurrence after resection surgery and display increased immune checkpoint programmed death ligand 1 (PD-L1) expression and pro-tumor regulatory T cells (Tregs) infiltration in tumor tissues. In this study, the association of higher levels of PD-L1 expression and Tregs infiltration in tumor tissues with post-operative HCC recurrence in pre-S2 mutant-positive HCC patients was evaluated. We found that patients with pre-S2 mutant in combination with higher levels of PD-L1 expression and Tregs infiltration in tumor tissues were independently associated with a higher risk of HCC recurrence (hazard ratio, 4.109; p value = 0.0011) and poorer recurrence-free survival (median, 8.2 versus 18.0 months; p value = 0.0004) than those of patients with either one or two of these three biomarkers. Furthermore, a combination of pre-S2 mutant, intra-tumoral PD-L1 expression, and tumor-infiltrating Tregs exhibited superior performance in identifying patients at a higher risk of HCC recurrence (area under the receiver operating characteristic curve, 0.8400). Collectively, this study suggests that higher levels of PD-L1 expression and Tregs infiltration in tumor tissues predicted a higher risk of HCC recurrence in pre-S2 mutant-positive HCC patients after curative surgical resection.

Hepatitis B Virus Pre-S Gene Deletions and Pre-S Deleted Proteins: Clinical and Molecular Implications in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most frequent and fatal human cancers worldwide and its development and prognosis are intimately associated with chronic infection with hepatitis B virus (HBV). The identification of genetic mutations and molecular mechanisms that mediate HBV-induced tumorigenesis therefore holds promise for the development of potential biomarkers and targets for HCC prevention and therapy. The presence of HBV pre-S gene deletions in the blood and the expression of pre-S deleted proteins in the liver tissues of patients with chronic hepatitis B and HBV-related HCC have emerged as valuable biomarkers for higher incidence rates of HCC development and a higher risk of HCC recurrence after curative surgical resection, respectively. Moreover, pre-S deleted proteins are regarded as important oncoproteins that activate multiple signaling pathways to induce DNA damage and promote growth and proliferation in hepatocytes, leading to HCC development. The signaling molecules dysregulated by pre-S deleted proteins have also been validated as potential targets for the prevention of HCC development. In this review, we summarize the clinical and molecular implications of HBV pre-S gene deletions and pre-S deleted proteins in HCC development and recurrence and highlight their potential applications in HCC prevention and therapy.

Genetic Biomarkers For Hepatocellular Carcinoma In The Era Of Precision Medicine

Being one of the most lethal cancers that exhibit high levels of heterogeneity, hepatocellular carcinoma (HCC) is associated with diverse oncogenic pathways underpinned by varied driver genes. HCC can be induced by different etiological factors including virus infection, toxin exposure or metabolic disorders. Consequently, patients may display varied genetic profiles, and may respond differently to the treatments involving inhibition of target pathways. These DNA/RNA mutations, copy number variations, chromatin structural changes, aberrant expression of non-coding RNAs and epigenetic modifications were considered as biomarkers in the application of precision medication. To explore how genetic testing could contribute to early diagnosis, prognosis, treatment and postoperative monitoring of HCC, we conducted a systematic review of genetic markers associated with different pathologies. Moreover, we summarized on-going clinical trials for HCC treatment, including the trials for multiple kinase inhibitors and immune checkpoint blockade (ICB). The efficacy of ICB treatment in HCC is not as good as what was observed in lung cancer and melanoma, which might be due to the heterogeneity of the microenvironment of the liver.

Chemoprotective effect of nanocurcumin on 5-fluorouracil-induced-toxicity toward oral cancer treatment

Introduction

Cancer of oral cavity is the uncontrolled expansion of damaged cell within the mouth cavity. 5-fluorouracil (5-FU) chemotherapy was focused to kill the cancer cell, but it would affect the surrounding normal cells during oral cancer treatment. This study included the evaluation of chemoprotective effects of curcumin (CU), as an herbal remedy, on 5-FU-induced-cytotoxicity toward oral cancer treatment, loaded within a nanocarrier system. CU was combined with 5-FU chemotherapy as a combinational drug-delivery system to evaluate synergistic effects.

Materials and Methods

Nanoformulation of CU (nano-CU) and nanoformulation of 5-FU (nano-FU) were prepared by employing homogenization with high-energy sonication. The characterizations of prepared nanoformulations were evaluated on the basis of particle size, zeta potential, and polydispersity index (PDI) values. The chemopreventive effect of nano-CU on 5-FU induced-toxicity and synergistic efficacy were optimized through different in-vitro assays.

Results

The average particle size of nano-CU and nano-FU were up to 200 nm, negatively-charged, and shown up to 4^th-day control release of the drug within the acceptable concentration. IC₅₀ value for growth inhibition was calculated as 47.89 and 26.19 μg/ml, respectively, for nano-CU and nano-FU. OCC was pretreated with nano-CU and shown the protective effect by reducing 5-FU induced-cytotoxicity by preventing normal cells through reduced viability. The DPPH-indicated fluorescence-tagged cells had quantified for antioxidant effect as it reduces intracellular reactive oxygen species level in OCC. Along with alteration in cell protein expression, Blc2, and Bax, shows enhanced apoptosis rate in OCC.

Conclusion

Nano-CU provides chemoprotective nature towards 5-FU induced-toxicity, along with synergistic effects in oral cancer treatment.

Enhancing the Anticancer Activity of Antrodia cinnamomea in Hepatocellular Carcinoma Cells via Cocultivation With Ginger: The Impact on Cancer Cell Survival Pathways

Antrodia cinnamomea (AC) is a medicinal fungal species that has been widely used traditionally in Taiwan for the treatment of diverse health-related conditions including cancer. It possesses potent anti-inflammatory and antioxidant properties in addition to its ability to promote cancer cell death in several human tumors. Our aim was to improve the anticancer activity of AC in hepatocellular carcinoma (HCC) through its cocultivation with ginger aiming at tuning the active ingredients. HCC cell lines, Huh-7 and HepG2 were used to study the in vitro anticancer activity of the ethanolic extracts of AC (EAC) alone or after the cocultivation in presence of ginger (EACG). The results indicated that the cocultivation of AC with ginger significantly induced the production of important triterpenoids and EACG was significantly more potent than EAC in targeting HCC cell lines. EACG effectively inhibited cancer cells growth via the induction of cell cycle arrest at G2/M phase and induction of apoptosis in Huh-7 and HepG2 cells as indicated by MTT assay, cell cycle analysis, Annexin V assay, and the activation of caspase-3. In addition, EACG modulated cyclin proteins expression and mitogen-activated protein kinase (MAPK) signaling pathways in favor of the inhibition of cancer cell survival. Taken together, the current study highlights an evidence that EACG is superior to EAC in targeting cancer cell survival and inducing apoptotic cell death in HCC. These findings support that EACG formula can serve as a potential candidate for HCC adjuvant therapy.

Hepatitis B virus PreS2-mutant large surface antigen activates store-operated calcium entry and promotes chromosome instability

Hepatitis B virus (HBV) is a driver of hepatocellular carcinoma, and two viral products, X and large surface antigen (LHBS), are viral oncoproteins. During chronic viral infection, immune-escape mutants on the preS2 region of LHBS (preS2-LHBS) are gain-of-function mutations that are linked to preneoplastic ground glass hepatocytes (GGHs) and early disease onset of hepatocellular carcinoma. Here, we show that preS2-LHBS provoked calcium release from the endoplasmic reticulum (ER) and triggered stored-operated calcium entry (SOCE). The activation of SOCE increased ER and plasma membrane (PM) connections, which was linked by ER- resident stromal interaction molecule-1 (STIM1) protein and PM-resident calcium release- activated calcium modulator 1 (Orai1). Persistent activation of SOCE induced centrosome overduplication, aberrant multipolar division, chromosome aneuploidy, anchorage-independent growth, and xenograft tumorigenesis in hepatocytes expressing preS2- LHBS. Chemical inhibitions of SOCE machinery and silencing of STIM1 significantly reduced centrosome numbers, multipolar division, and xenograft tumorigenesis induced by preS2-LHBS. These results provide the first mechanistic link between calcium homeostasis and chromosome instability in hepatocytes carrying preS2-LHBS. Therefore, persistent activation of SOCE represents a novel pathological mechanism in HBV-mediated hepatocarcinogenesis.

MicroRNA profile in HBV-induced infection and hepatocellular carcinoma

Background

MicroRNAs (miRNAs) exhibit essential regulatory functions related to cell growth, apoptosis, development and differentiation. Dysregulated expression of miRNAs is associated with a wide variety of human diseases. As such miRNA signatures are valuable as biomarkers for disease and for making treatment decisions. Hepatitis B virus (HBV) is a major risk factor for hepatocellular carcinoma (HCC). Here we screened for miRNAs in chronic HBV associated HCC.

Methods

To determine the miRNAs in HCC occurrence associated with HBV infection, we analyzed global miRNA expression profiles in 12 pairs of HCC and adjacent matched non-HCC tissues from HBV-positive and HBV-negative patients using microarray analyses. The microarray result was validated by real-time PCR in 32 HBV-positive and 24 HBV-negative patient HCC samples. The potential candidate target genes of the miRNAs were predicted by miRWalk software. Genes simultaneously predicted as targets by two or more miRNAs were subjected to GO and KEGG pathway analysis. The miRNA regulatory network analysis was performed using the Ingenuity Pathway Analysis (IPA) software.

Results

Eight miRNAs (miR-223, miR-98, miR-15b, miR-199a-5p, miR-19b, miR-22, miR-451, and miR-101) were involved in HBV-unrelated HCC, 5 miRNAs (miR-98, miR-375, miR-335, miR-199a-5p, and miR-22) were involved in HBV infection, and 7 miRNAs (miR-150, miR-342-3p, miR-663, miR-20b, miR-92a-3p, miR-376c-3p and miR-92b) were specifically altered in HBV-related HCC. Gene Ontology and KEGG analyses predict that these HBV-related HCC miRNAs are involved in the regulation of: transcription, RNA polymerase II promoter, phosphorylation of proteins through MAPK signaling pathway, focal adhesion, and actin cytoskeleton. IPA analysis also suggest that these miRNAs act on AGO2, TP53, CCND1, and 11 other genes that significantly influence HCC occurrence and HBV infection.

Conclusion

Our data indicates that the unique 7 miRNAs expression signature could be involved in the development HBV- related HCC.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3816-1) contains supplementary material, which is available to authorized users.

Interference of Apoptosis by Hepatitis B Virus

Hepatitis B virus (HBV) causes liver diseases that have been a consistent problem for human health, leading to more than one million deaths every year worldwide. A large proportion of hepatocellular carcinoma (HCC) cases across the world are closely associated with chronic HBV infection. Apoptosis is a programmed cell death and is frequently altered in cancer development. HBV infection interferes with the apoptosis signaling to promote HCC progression and viral proliferation. The HBV-mediated alteration of apoptosis is achieved via interference with cellular signaling pathways and regulation of epigenetics. HBV X protein (HBX) plays a major role in the interference of apoptosis. There are conflicting reports on the HBV interference of apoptosis with the majority showing inhibition of and the rest reporting induction of apoptosis. In this review, we described recent studies on the mechanisms of the HBV interference with the apoptosis signaling during the virus infection and provided perspective.

Alginate-embedded HuH-7 cells increase MMP-9 and reduce OCLN expression in vitro

BACKGROUND

Hepatocellular carcinoma is a common cancer, ranking third in cancer-associated deaths. An important cause of cancer patients' mortality is metastasis. At the start of metastasis progression, there is an epithelial-mesenchymal transition, characterized by matrix degradation, junction reductions and vessels formation. HuH-7 is a cell line used in research as an in vitro model for hepatocellular carcinoma. It is known that two-dimensional growth reflects tumor characteristics poorly. In contrast, three-dimensional cultures provide a better approach to the study of tumorigenic potential. The purpose of this work was to mimic a three-dimensional environment in order to assess gene expression of some epithelial-mesenchymal transition and metastasis progression markers in HuH-7 cells and compare them with traditional two-dimensional culture model.

METHODS

HuH-7 cells were encapsulated in sodium alginate (three-dimensional model) to be compared with cells grown in two-dimensional flasks. After 4 days in culture, gene expression of Matrix metallopeptidase 9, Occludin, p65, Intercellular adhesion molecule 1 and Vascular endothelial growth factor A was analyzed by qPCR and cytoskeleton assessment was performed by rhodamine-phalloidin staining.

RESULTS

Differences were found in gene expression, with a high increment of Matrix metallopeptidase 9 and Occludin reduction. The cytoskeleton morphology also showed differences, with a cytoplasm restricted only near the nuclei in the three-dimensional model.

CONCLUSIONS

This work shows the effects of using sodium alginate capsules as a three-dimensional model to the study of HuH-7. Cells in this 3D system show key markers of epithelial-mesenchymal transition, such as Matrix metallopeptidase 9 overexpression and Occludin down-regulation.

Delivery of drugs and macromolecules to the mitochondria for cancer therapy

Mitochondria are organelles that have pivotal functions in producing the energy necessary for life and executing the cell death pathway. Targeting drugs and macromolecules to the mitochondria may provide an effective means of inducing cell death for cancer therapy, and has been actively pursued in the last decade. This review will provide a brief overview of mitochondrial structure and function, how it relates to cancer, and importantly, will discuss different strategies of mitochondrial delivery including delivery using small molecules, peptides, genes encoding proteins and MTSs, and targeting polymers/nanoparticles with payloads to the mitochondria. The advantages and disadvantages for each strategy will be discussed. Specific examples using the latest strategies for mitochondrial targeting will be evaluated, as well as potential opportunities for specific mitochondrial compartment localization, which may lead to improvements in mitochondrial therapeutics. Future perspectives in mitochondrial targeting of drugs and macromolecules will be discussed. Currently this is an under-explored area that is prime for new discoveries in cancer therapeutics.

Differences in antiproliferative effect of STAT3 inhibition in HCC cells with versus without HBV expression

Chronic infection with hepatitis B virus (HBV) plays an important role in the etiology of hepatocellular carcinoma (HCC). Signal transducer and activator of transcription 3 (STAT3) inactivation could inhibit the tumor growth of HCC. In this study, differential antiproliferative effect of STAT3 inhibition was observed with HBV-related HCC cells being more resistant than non-HBV-related HCC cells. Resistance of HBV-related HCC cells to STAT3 inhibition was positively correlated to the expression of HBV. Enhanced ERK activation after STAT3 blockade was detected in HBV-related HCC cells but not in non-HBV-related HCC cells. Combined ERK and STAT3 inhibition eliminates the discrepancy between the two types of HCC cells. Moderate reduced HBV expression was found after STAT3 inhibition. These findings disclose a discrepancy in cellular response to STAT3 inhibition between non-HBV-related and HBV-related HCC cells and underscore the complexity of antiproliferative effect of STAT3 inactivation in HBV-related HCC cells.

Novel approach to identifying the hepatitis B virus pre-S deletions associated with hepatocellular carcinoma

AIM: To develop a novel non-sequencing method for the detection of hepatitis B virus (HBV) pre-S deletion mutants in HBV carriers.

METHODS: The entire region of HBV pre-S1 and pre-S2 was amplified by polymerase chain reaction (PCR). The size of PCR products was subsequently determined by capillary gel electrophoresis (CGE). CGE were carried out in a PACE-MDQ instrument equipped with a UV detector set at 254 nm. The samples were separated in 50 μm ID eCAP Neutral Coated Capillaries using a voltage of 6 kV for 30 min. Data acquisition and analysis were performed using the 32 Karat Software. A total of 114 DNA clones containing different sizes of the HBV pre-S gene were used to determine the accuracy of the CGE method. One hundred and fifty seven hepatocellular carcinoma (HCC) and 160 non-HCC patients were recruited into the study to assess the association between HBV pre-S deletion and HCC by using the newly-established CGE method. Nine HCC cases with HBV pre-S deletion at the diagnosis year were selected to conduct a longitudinal observation using serial serum samples collected 2-9 years prior to HCC diagnosis.

RESULTS: CGE allowed the separation of PCR products differing in size > 3 bp and was able to identify 10% of the deleted DNA in a background of wild-type DNA. The accuracy rate of CGE-based analysis was 99.1% compared with the clone sequencing results. Using this assay, pre-S deletion was more frequently found in HCC patients than in non-HCC controls (47.1% vs 28.1%, P < 0.001). Interestingly, the increased risk of HCC was mainly contributed by the short deletion of pre-S. While the deletion ≤ 99 bp was associated with a 2.971-fold increased risk of HCC (95%CI: 1.723-5.122, P < 0.001), large deletion (> 99 bp) did not show any association with HCC (P = 0.918, OR = 0.966, 95%CI: 0.501-1.863). Of the 9 patients who carried pre-S deletions at the stage of HCC, 88.9% (8/9) had deletions 2-5 years prior to HCC, while only 44.4%4 (4/9) contained such deletions 6-9 years prior to HCC.

CONCLUSION: CGE is a sensitive approach for HBV pre-S deletion analysis. Pre-S deletion, especially for short DNA fragment deletion, is a useful predictive marker for HCC.

Induction of apurinic endonuclease 1 overexpression by endoplasmic reticulum stress in hepatoma cells

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide with poor prognosis due to resistance to conventional chemotherapy and limited efficacy of radiotherapy. Previous studies have noted the induction of endoplasmic reticulum stress or apurinic endonuclease 1 (APE1) expression in many tumors. Therefore, the aim of this study was to investigate the relationship between endoplasmic reticulum (ER stress) and APE1 in hepatocellular carcinoma. Here we investigate the expression of APE1 during ER stress in HepG2 and Huh-7 cell lines. Tunicamycin or brefeldin A, two ER stress inducers, increased APE1 and GRP78, an ER stress marker, expression in HepG2 and Huh-7 cells. Induction of APE1 expression was observed through transcription level in response to ER stress. APE1 nuclear localization during ER stress was determined using immunofluorescence assays in HepG2 cells. Furthermore, expression of Hepatitis B virus pre-S2∆ large mutant surface protein (pre-S2∆), an ER stress-induced protein, also increased GRP78 and APE1 expression in the normal hepatocyte NeHepLxHT cell line. Similarly, tumor samples showed higher expression of APE1 in ER stress-correlated liver cancer tissue in vivo. Our results demonstrate that ER stress and HBV pre-S2∆ increased APE1 expression, which may play an important role in resistance to chemotherapeutic agents or tumor development. Therefore, these data provide an important chemotherapeutic strategy in ER stress and HBV pre-S2∆-associated tumors.

Unfolded protein response in hepatitis C virus infection

Hepatitis C virus (HCV) is a single-stranded, positive-sense RNA virus of clinical importance. The virus establishes a chronic infection and can progress from chronic hepatitis, steatosis to fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). The mechanisms of viral persistence and pathogenesis are poorly understood. Recently the unfolded protein response (UPR), a cellular homeostatic response to endoplasmic reticulum (ER) stress, has emerged to be a major contributing factor in many human diseases. It is also evident that viruses interact with the host UPR in many different ways and the outcome could be pro-viral, anti-viral or pathogenic, depending on the particular type of infection. Here we present evidence for the elicitation of chronic ER stress in HCV infection. We analyze the UPR signaling pathways involved in HCV infection, the various levels of UPR regulation by different viral proteins and finally, we propose several mechanisms by which the virus provokes the UPR.

Modulation of cyclins, p53 and mitogen-activated protein kinases signaling in breast cancer cell lines by 4-(3,4,5-trimethoxyphenoxy)benzoic acid

Despite the advances in cancer therapy and early detection, breast cancer remains a leading cause of cancer-related deaths among females worldwide. The aim of the current study was to investigate the antitumor activity of a novel compound, 4-(3,4,5-trimethoxyphenoxy)benzoic acid (TMPBA) and its mechanism of action, in breast cancer. Results indicated the relatively high sensitivity of human breast cancer cell-7 and MDA-468 cells towards TMPBA with IC₅₀ values of 5.9 and 7.9 μM, respectively compared to hepatocarcinoma cell line Huh-7, hepatocarcinoma cell line HepG2, and cervical cancer cell line Hela cells. Mechanistically, TMPBA induced apoptotic cell death in MCF-7 cells as indicated by 4′,6-diamidino-2-phenylindole (DAPI) nuclear staining, cell cycle analysis and the activation of caspase-3. Western blot analysis revealed the ability of TMPBA to target pathways mediated by mitogen-activated protein (MAP) kinases, 5′ adenosine monophosphate-activated protein kinase (AMPK), and p53, of which the concerted action underlined its antitumor efficacy. In addition, TMPBA induced alteration of cyclin proteins’ expression and consequently modulated the cell cycle. Taken together, the current study underscores evidence that TMPBA induces apoptosis in breast cancer cells via the modulation of cyclins and p53 expression as well as the modulation of AMPK and mitogen-activated protein kinases (MAPK) signaling. These findings support TMPBA’s clinical promise as a potential candidate for breast cancer therapy.

Correlation and prognostic value of osteopontin and Bcl-2 in hepatocellular carcinoma patients after curative resection

Osteopontin (OPN) may facilitate tumorigenesis and metastasis through prevention of tumor cells from apoptosis. Although previous studies have suggested involvement of enhanced Bcl-2 protein family expression, the role of OPN together with Bcl-2 in hepatocellular carcinoma (HCC) remains unknown. In this study, we used western blotting to detect the OPN and Bcl-2 expression levels in cell lines with different OPN backgrounds and HCC tissues, and tumor tissue microarrays to examine OPN and Bcl-2 expression levels in 454 HCC cases. The Kaplan-Meier method and log-rank test were applied to investigate the predictive values of OPN and Bcl-2 in HCC patients. In vitro assays indicated that OPN expression increased concordantly with increasing metastatic potential in MHCC97-H, MHCC97-L, HepG2 and SMMC-7721 cell lines by western blotting, whereas Bcl-2 expression declined. In addition, Bcl-2 was highly upregulated in OPN knockdown MHCC97-H cell lines. Furthermore, in HCC tissues, it was confirmed that OPN levels were also significantly higher in recurrent tumor tissues compared to non-recurrent tissues by western blotting (p<0.001), whereas the contrary occurred in Bcl-2 (p=0.046). Using immunohistochemistry analysis, patients with higher OPN levels had significantly shorter median survival time and recurrence time compared to the lower ones, although the opposite occurred in Bcl-2 levels. Of note, when OPN and Bcl-2 were combined, we found that the co-index of OPN/Bcl-2 was an independent prognostic factor for both overall survival (p<0.001) and time to recurrence (p<0.001). Our findings demonstrate that OPN/Bcl-2 expression is a promising independent predictor of recurrence and survival in HCC. Additionally, Bcl-2 levels may be regulated by OPN in the HCC microenvironment.

HBV induced HCC: major risk factors from genetic to molecular level

Hepatocellular carcinoma (HCC) is a deadly and emerging disease leading to death in Asian countries. High hepatitis B virus (HBV) load and chronic hepatitis B (CHB) infection increase the risk of developing HCC. HBV is a DNA virus that can integrate DNA into host genome thereby increase the yield of transactivator protein HBxAg that may deregulate many pathways involving in metabolism of cells. Several monogenic and polygenic risk factors are also involved in HCC development. This review summarizes the mechanism involved in HCC development and discusses some promising therapies to make HCC curative.

MicroRNA-34a targets Bcl-2 and sensitizes human hepatocellular carcinoma cells to sorafenib treatment

MiR-34a, a direct target of p53, has been shown to target several molecules associated with the cell cycle and cell survival pathways, and its dysregulation is implicated in cancer drug resistance or sensitivity in several human cancers. However, the correlation between miR-34a expression and chemoresistance has not been explored in HCC. In this study, we confirmed that miR-34a was significantly down-regulated in HCC tissues and HCC cell lines by qRT-PCR. HCC tissues with lower miR-34a expression displayed higher expression of Bcl-2 protein than those with high expression of miR-34a; therefore, an inverse correlation is evident between the miR-34a level and Bcl-2 expression. Moreover, patients with lower miR-34a expression had significantly poorer overall survival. Bioinformatics and luciferase reporter assays revealed that miR-34a binds the 3'-UTR of the Bcl-2 mRNA and represses its translation. Western blotting analysis and qRT-PCR confirmed that Bcl-2 is inhibited by miR-34a overexpression. Functional analyses indicated that the restoration of miR-34a reduced cell viability, promoted cell apoptosis and potentiated sorafenib-induced apoptosis and toxicity in HCC cell lines by inhibiting Bcl-2 expression. This study is the first to demonstrate that miR-34a induces sensitivity to the anti-tumor effect of sorafenib in human HCC cells, suggesting a potential role of miR-34a in the treatment of HCC.

Interferon-α sensitizes HBx-expressing hepatocarcinoma cells to chemotherapeutic drugs through inhibition of HBx-mediated NF-κB activation

Background

Hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) is characterized by high chemotherapy resistance; however, the underlying mechanism has not been fully clarified. In addition, HBx protein has been reported to play a key role in virus-mediated hepatocarcinogenesis. Therefore, the present study aims to investigate the role of HBx in the drug-resistance of HBV-related HCC and examine whether such drug-resistance can be reversed by IFN-α treatment.

Methods

We established HBx-expressing cells by liposome-mediated transfection of HBx into the Huh7 cell line. MTT, Annexin V/PI, and cell cycle assay were used for determining the cellular growth inhibition, apoptosis, and growth arrest, respectively, after treatment with chemical drug. We further used tumor-bearing mice model to compare the tumor growth inhibition efficacy of ADM and 5-FU between the Huh7-HBx group and the control group, as well as the ADM + IFN-α or ADM + IMD treated group and the ADM treated group. SQ-Real time-PCR was performed to analyze the expression of MDR-associated genes and anti-apoptotic genes. Moreover, immunofluorescence and Western blotting were used to determine the subcellular localization of p65 and the phosphorylation of IκBα.

Results

The IC₅₀ values of Huh7-HBx cells against ADM and Amn were 2.317 and 1.828-folds higher than those of Huh7-3.1 cells, respectively. The apoptosis ratio and growth arrest was significantly lower in Huh7-HBx cells after treatment with ADM. The in vivo experiment also confirmed that the Huh7-HBx group was much more resistant to ADM or 5-FU than the control. Furthermore, the expression of MDR-associated genes, such as MDR1, MRP1, LRP1, and ABCG2, were significantly up-regulated in Huh7-HBx cells, and the NF-κB pathway was activated after HBx gene transfection in Huh7 cells. However, combined with IFN-α in ADM treatment, the HBx induced drug-resistance in Huh7-HBx cells can be partly abolished in in vitro and in vivo models. Moreover, we found that the NF-κB canonical pathway was affected by IFN-α treatment, and the expression of anti-apoptotic genes, such as Gadd45β, Survivin, and c-IAP-1 was down-regulated by IFN-α treatment in a dose-dependent manner.

Conclusions

HBx protein can induce MDR of HBV-related HCC by activating the NF-κB pathway, which can be partly abolished by IFN-α treatment.

Interferon-α sensitizes HBx-expressing hepatocarcinoma cells to chemotherapeutic drugs through inhibition of HBx-mediated NF-κB activation

BACKGROUND

Hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) is characterized by high chemotherapy resistance; however, the underlying mechanism has not been fully clarified. In addition, HBx protein has been reported to play a key role in virus-mediated hepatocarcinogenesis. Therefore, the present study aims to investigate the role of HBx in the drug-resistance of HBV-related HCC and examine whether such drug-resistance can be reversed by IFN-α treatment.

METHODS

We established HBx-expressing cells by liposome-mediated transfection of HBx into the Huh7 cell line. MTT, Annexin V/PI, and cell cycle assay were used for determining the cellular growth inhibition, apoptosis, and growth arrest, respectively, after treatment with chemical drug. We further used tumor-bearing mice model to compare the tumor growth inhibition efficacy of ADM and 5-FU between the Huh7-HBx group and the control group, as well as the ADM + IFN-α or ADM + IMD treated group and the ADM treated group. SQ-Real time-PCR was performed to analyze the expression of MDR-associated genes and anti-apoptotic genes. Moreover, immunofluorescence and Western blotting were used to determine the subcellular localization of p65 and the phosphorylation of IκBα.

RESULTS

The IC₅₀ values of Huh7-HBx cells against ADM and Amn were 2.317 and 1.828-folds higher than those of Huh7-3.1 cells, respectively. The apoptosis ratio and growth arrest was significantly lower in Huh7-HBx cells after treatment with ADM. The in vivo experiment also confirmed that the Huh7-HBx group was much more resistant to ADM or 5-FU than the control. Furthermore, the expression of MDR-associated genes, such as MDR1, MRP1, LRP1, and ABCG2, were significantly up-regulated in Huh7-HBx cells, and the NF-κB pathway was activated after HBx gene transfection in Huh7 cells. However, combined with IFN-α in ADM treatment, the HBx induced drug-resistance in Huh7-HBx cells can be partly abolished in in vitro and in vivo models. Moreover, we found that the NF-κB canonical pathway was affected by IFN-α treatment, and the expression of anti-apoptotic genes, such as Gadd45β, Survivin, and c-IAP-1 was down-regulated by IFN-α treatment in a dose-dependent manner.

CONCLUSIONS

HBx protein can induce MDR of HBV-related HCC by activating the NF-κB pathway, which can be partly abolished by IFN-α treatment.

Knockdown of the Bcl-2 gene increases sensitivity to EGFR tyrosine kinase inhibitors in the H1975 lung cancer cell line harboring T790M mutation

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are being widely used as targeted therapy in non-small cell lung cancer (NSCLC), but most cases acquire drug-resistance in 9 months. However, the mechanisms of resistance are still not fully understood. Since it has been demonstrated that EGFR-TKI-mediated repression of downstream signaling cascades and apoptosis induction is a key mechanism through which EGFR-TKIs exert their cytotoxic effects, we reasoned that activation of downstream signaling pathways and changes in the expression of apoptosis-related proteins contribute to the acquired resistance to EGFR-TKIs. We analyzed the protein levels of p-Akt, Bcl-2, Bax between gefitinib-sensitive and gefitinib-resistant lung cancer cell lines and evaluated whether targeting the anti-apoptotic protein Bcl-2 induces cell apoptosis and further sensitizes resistant H1975 cells to gefitinib. The data showed that p-Akt was activated and accompanied by substantial Bcl-2 in the H1975 lung cancer cell line, whereas no evidence was observed in HCC827 cells. Using small interfering RNA (siRNA) to silence Bcl-2 in H1975 cells led to significant downregulation of Bcl-2 protein expression, decreased cell viability in vitro and induced intrinsic apoptosis confirmed by flow cytometry and PARP cleavage. In Bcl-2 siRNA-transfected cells, adding gefitinib further reduced the number of viable cells, induced apoptosis to a greater extent compared to either treatment alone. These preclinical data suggested that downregulation of Bcl-2 by RNAi in the gefitinib-resistant H1975 lung cancer cell line with T790M mutation enhanced the effects of gefitinib and may offer a novel therapeutic strategy for the treatment of NSCLC.