Mechanisms of Sorafenib Resistance in HCC Culture Relate to the Impaired Membrane Expression of Organic Cation Transporter 1 (OCT1).

Introduction: Sorafenib, an FDA-approved drug for advanced hepatocellular carcinoma (HCC) treatment, encounters resistance in many patients. Deciphering the mechanisms underlying sorafenib resistance is crucial for devising alternative strategies to overcome it. Aim: This study aimed to investigate sorafenib resistance mechanisms using a diverse panel of HCC cell lines. Methods: HCC cell lines were subjected to continuous sorafenib treatment, and stable cell lines (Huh 7.5 and Huh 7PX) exhibiting sustained growth in its presence were isolated. The investigation of drug resistance mechanisms involved a comparative analysis of drug-targeted signal transduction pathways (EGFR/RAF/MEK/ERK/Cyclin D), sorafenib uptake, and membrane expression of the drug uptake transporter. Results: HCC cell lines (Huh 7.5 and Huh 7PX) with a higher IC50 (10µM) displayed a more frequent development of sorafenib resistance compared to those with a lower IC50 (2-4.8µM), indicating a potential impact of IC50 variation on initial treatment response. Our findings reveal that activated overexpression of Raf1 kinases and impaired sorafenib uptake, mediated by reduced membrane expression of organic cation transporter-1 (OCT1), contribute to sorafenib resistance in HCC cultures. Stable expression of the drug transporter OCT1 through cDNA transfection or adenoviral delivery of OCT1 mRNA increased sorafenib uptake and successfully overcame sorafenib resistance. Additionally, consistent with sorafenib resistance in HCC cultures, cirrhotic liver-associated human HCC tumors often exhibited impaired membrane expression of OCT1 and OCT3. Conclusion: Intrinsic differences among HCC cell clones, affecting sorafenib sensitivity at the expression level of Raf kinases, drug uptake, and OCT1 transporters, were identified. This study underscores the potential of HCC tumor targeted OCT1 expression to enhance sorafenib treatment response.

A Single-Step Immunocapture Assay to Quantify HCC Exosomes Using the Highly Sensitive Fluorescence Nanoparticle-Tracking Analysis.

Introduction: Extracellular vesicles could serve as a non-invasive biomarker for early cancer detection. However, limited methods to quantitate cancer-derived vesicles in the native state remain a significant barrier to clinical translation. Aim: This research aims to develop a rapid, one-step immunoaffinity approach to quantify HCC exosomes directly from a small serum volume. Methods: HCC-derived exosomes in the serum were captured using fluorescent phycoerythrin (PE)-conjugated antibodies targeted to GPC3 and alpha-fetoprotein (AFP). Total and HCC-specific exosomes were then quantified in culture supernatant or patient-derived serums using fluorescence nanoparticle tracking analysis (F-NTA). The performance of HCC exosome quantification in the serum was compared with the tumor size determined by MRI. Results: Initially we tested the detection limits of the F-NTA using synthetic fluorescent and non-fluorescent beads. The assay showed an acceptable sensitivity with a detection range of 104-108 particles/mL. Additionally, the combination of immunocapture followed by size-exclusion column purification allows the isolation of smaller-size EVs and quantification by F-NTA. Our assay demonstrated that HCC cell culture releases a significantly higher quantity of GPC3 or GPC3+AFP positive EVs (100-200 particles/cell) compared to non-HCC culture (10-40 particles/cell) (p<0.01 and p<0.05 respectively). The F-NTA enables absolute counting of HCC-specific exosomes in the clinical samples with preserved biological immunoreactivity. The performance of F-NTA was clinically validated in serum from patients ± cirrhosis and with confirmed HCC. F-NTA quantification data show selective enrichment of AFP and GPC3 positive EVs in HCC serum compared to malignancy-free cirrhosis (AUC values for GPC3, AFP, and GPC3/AFP were found 0.79, 0.71, and 0.72 respectively). The MRI-confirmed patient cohort indicated that there was a positive correlation between total tumor size and GPC3-positive exosome concentration (r:0.78 and p<0.001). Conclusion: We developed an immunocapture assay that can be used for simultaneous isolation and quantification of HCC-derived exosomes from a small serum volume with high accuracy.

The number of hepatocellular carcinoma foci as predictor of poor response to tumor-directed therapies in patients awaiting liver transplantation: a prospective cohort study.

BACKGROUND AND AIMS: Tumor-directed therapies (TDTs) are a constitutive part of hepatocellular carcinoma (HCC) treatment in patients awaiting liver transplantation (LT). While most patients benefit from TDTs as a bridge to LT, some patients drop out from the waiting list due to tumor progression. The study aimed to determine the risk factors for poor treatment outcome following TDTs among patients with HCC awaiting LT. METHODS: A total of 123 patients with HCC were evaluated with 92 patients meeting Milan Criteria enrolled in the prospective cohort study. Tumor response was evaluated using the modified Response Evaluation Criteria for Solid Tumors for HCC 1 month after the procedure. The risk factors for progressive disease (PD) and dropout were evaluated. RESULTS: After TDT, 55 patients (59.8%) achieved complete or partial response (44.6% and 15.2% respectively), 17 patients (18.5%) had stable disease, and 20 patients (21.7%) were assessed as PD. Multivariate analysis revealed a significant and independent association between the number of HCC foci and PD ( P  = 0.03, OR = 2.68). There was no statistically significant association between treatment response and demographics, MELDNa score, pre-and post-treatment alpha-fetoprotein (AFP), cumulative tumor burden the largest tumor size, or TDT modality. PD was the major cause of dropout in our cohort. Pre-treatment AFP levels ≥200 ng/ml had a strong association with dropout after TDTs ( P  = 0.0005). CONCLUSION: This study demonstrated the presence of multifocal HCC is the sole prognostic factor for PD following TDTs in HCC patients awaiting LT. We recommend prioritizing patients with multifocal HCC within Milan criteria by exception points for LT to improve the dropout rate.

A Rectal Sunflower Seed Bezoar Causing Fecal Impaction in a Healthy Young Woman.

Bezoars, characterized by undigested or partially digested foreign bodies in the gastrointestinal (GI) tract, are a rare condition associated with significant complications. We present a case of a 31-year-old woman who sought medical attention due to weight loss, diarrhea, and anorectal pain. Upon investigation, she was diagnosed with fecal impaction caused by a rectal sunflower seed bezoar. The patient had a history of regular sunflower seed consumption, suggesting a potential association with the development of the bezoar. Fecal impaction resulting from the bezoar led to chronic constipation, contributing to the patient's weight loss and anorectal discomfort. Imaging studies, including abdominal X-rays or computed tomography (CT) scans, played a crucial role in confirming the diagnosis by identifying the presence of the bezoar within the rectum. Management involved a multidisciplinary approach, with gastroenterologists and colorectal surgeons. A flexible endoscope was utilized to visualize and remove the sunflower seed bezoar under direct vision, providing immediate relief from the symptoms. This case emphasizes the importance of considering bezoars as a potential cause of GI symptoms, even in young and otherwise healthy individuals. Although rectal bezoars are relatively rare, they can lead to significant morbidity. Therefore, it is essential to include them in the differential diagnosis of patients presenting with fecal impaction, anorectal pain, and associated symptoms. Prompt diagnosis, appropriate imaging, and early intervention are crucial for the successful management and prevention of potential complications and the improvement of patient outcomes.

Severe Anaplasmosis With Multiorgan Involvement in a Rheumatoid Arthritis Patient.

Anaplasmosis, caused by the tick-borne bacterium Anaplasma phagocytophilum, is an emerging infectious disease with a broad spectrum of clinical manifestations. Here, we present a case report of a 66-year-old Caucasian woman residing in Connecticut who exhibited severe anaplasmosis with multi-organ involvement. The patient, with a medical history of rheumatoid arthritis and hypothyroidism, presented with confusion, lethargy, fever, myalgia, generalized weakness, and poor appetite in May 2023. Laboratory investigations revealed pancytopenia, hyponatremia, elevated liver enzymes with mild hyperbilirubinemia, and lactic acidosis. A buffy coat smear analysis demonstrated basophilic intracytoplasmic inclusion bodies in the neutrophils, supporting the diagnosis of severe anaplasmosis. Prompt administration of doxycycline, the recommended treatment for anaplasmosis, was initiated. However, the patient subsequently developed acute respiratory distress syndrome (ARDS) necessitating heated humidified high-flow nasal cannula (HFNC) therapy. Anaplasma polymerase chain reaction (PCR) confirmed the presence of the bacterium in the patient's blood. Following doxycycline treatment, the patient demonstrated improvement in peripheral blood findings, resolution of ARDS, and complete neurologic recovery. This case underscores the potential severity and diverse clinical manifestations of anaplasmosis, highlighting the importance of early recognition, prompt diagnosis, and timely initiation of appropriate treatment to prevent severe complications and improve patient outcomes.

Successful Resection of Gastric Subepithelial Lipoma Using the Bite-on-Bite Approach: Reviving Old Techniques in a Peripheral Hospital.

Subepithelial lesions (SELs) are common findings in the gastrointestinal (GI) tract. They are often benign and asymptomatic but can cause symptoms in some cases. The approach to endoscopic management of these lesions depends on various factors, including associated symptoms, location, available equipment, and operator expertise. In this case report, we present a 50-year-old male with long-standing dyspepsia who was found to have a submucosal lesion in the stomach. The lesion was successfully treated using the bite-on-bite method with cold biopsy forceps. This report aims to discuss gastric subepithelial lesions and current management options, and highlight an old technique for endoscopists in the era of advanced endoscopy.

Targeting ER stress/PKA/GSK-3ß/ß-catenin pathway as a potential novel strategy for hepatitis C virus-infected patients.

BACKGROUND: Chronic hepatitis C virus (HCV) infection causes hepatocellular carcinoma (HCC). The HCC risk, while decreased compared with active HCV infection, persists in HCV-cured patients by direct-acting antiviral agents (DAA). We previously demonstrated that Wnt/ß-catenin signaling remained activated after DAA-mediated HCV eradication. Developing therapeutic strategies to both eradicate HCV and reverse Wnt/ß-catenin signaling is needed. METHODS: Cell-based HCV long term infection was established. Chronically HCV infected cells were treated with DAA, protein kinase A (PKA) inhibitor H89 and endoplasmic reticulum (ER) stress inhibitor tauroursodeoxycholic acid (TUDCA). Western blotting analysis and fluorescence microscopy were performed to determine HCV levels and component levels involved in ER stress/PKA/glycogen synthase kinase-3ß (GSK-3ß)/ß-catenin pathway. Meanwhile, the effects of H89 and TUDCA were determined on HCV infection. RESULTS: Both chronic HCV infection and replicon-induced Wnt/ß-catenin signaling remained activated after HCV and replicon eradication by DAA. HCV infection activated PKA activity and PKA/GSK-3ß-mediated Wnt/ß-catenin signaling. Inhibition of PKA with H89 both repressed HCV and replicon replication and reversed PKA/GSK-3ß-mediated Wnt/ß-catenin signaling in both chronic HCV infection and replicon. Both chronic HCV infection and replicon induced ER stress. Inhibition of ER stress with TUDCA both repressed HCV and replicon replication and reversed ER stress/PKA/GSK-3ß-dependent Wnt/ß-catenin signaling. Inhibition of either PKA or ER stress both inhibited extracellular HCV infection. CONCLUSION: Targeting ER stress/PKA/GSK-3ß-dependent Wnt/ß-catenin signaling with PKA inhibitor could be a novel therapeutic strategy for HCV-infected patients to overcomes the issue of remaining activated Wnt/ß-catenin signaling by DAA treatment. Video Abstract.

Promotion of a synthetic degradation of activated STAT6 by PARP-1 inhibition: roles of poly(ADP-ribosyl)ation, calpains and autophagy.

BACKGROUND: We reported that PARP-1 regulates genes whose products are crucial for asthma, in part, by controlling STAT6 integrity speculatively through a calpain-dependent mechanism. We wished to decipher the PARP-1/STAT6 relationship in the context of intracellular trafficking and promoter occupancy of the transcription factor on target genes, its integrity in the presence of calpains, and its connection to autophagy. METHODS: This study was conducted using primary splenocytes or fibroblasts derived from wild-type or PARP-1-/- mice and Jurkat T cells to mimic Th2 inflammation. RESULTS: We show that the role for PARP-1 in expression of IL-4-induced genes (e.g. gata-3) in splenocytes did not involve effects on STAT6 phosphorylation or its subcellular trafficking, rather, it influenced its occupancy of gata-3 proximal and distal promoters in the early stages of IL-4 stimulation. At later stages, PARP-1 was crucial for STAT6 integrity as its inhibition, pharmacologically or by gene knockout, compromised the fate of the transcription factor. Calpain-1 appeared to preferentially degrade JAK-phosphorylated-STAT6, which was blocked by calpastatin-mediated inhibition or by genetic knockout in mouse fibroblasts. The STAT6/PARP-1 relationship entailed physical interaction and modification by poly(ADP-ribosyl)ation independently of double-strand-DNA breaks. Poly(ADP-ribosyl)ation protected phosphorylated-STAT6 against calpain-1-mediated degradation. Additionally, our results show that STAT6 is a bonafide substrate for chaperone-mediated autophagy in a selective and calpain-dependent manner in the human Jurkat cell-line. The effects were partially blocked by IL-4 treatment and PARP-1 inhibition. CONCLUSIONS: The results demonstrate that poly(ADP-ribosyl)ation plays a critical role in protecting activated STAT6 during Th2 inflammation, which may be synthetically targeted for degradation by inhibiting PARP-1.

Impaired Autophagy Response in Hepatocellular Carcinomas Enriches Glypican-3 in Exosomes, Not in the Microvesicles.

Background and Aim: HCC development in liver cirrhosis is associated with impaired autophagy leading to increased production of extracellular vesicles (EVs) including exosomes and microvesicles. The goal of the study is to determine which of these particles is primarily involved in releasing of HCC-specific biomarker glypican-3 (GPC3) when autophagy is impaired. Methods: Streptavidin-coated magnetic beads were coupled with either biotinylated CD63 or Annexin A1 antibodies. Coupled beads were incubated with EVs isolated from either HCC culture or serum. EVs captured by immuno-magnetic beads were then stained with FITC or PE fluorescent-conjugated antibodies targeting exosomes (CD81), and microvesicles (ARF6). The percentage of GPC3 enrichment in the microvesicles and exosomes was quantified by flow cytometry. The impact of autophagy modulation on GPC3 enrichment in exosomes and microvesicles was assessed by treating cells with Torin 1 and Bafilomycin A1. For clinical validation, GPC3 content was quantified in microvesicles, and exosomes were isolated from the serum of patients with a recent HCC diagnosis. Results: The immune-magnetic bead assay distinguishes membrane-derived microvesicles from endosome-derived exosomes. The GPC3 expression was only seen in the CD63 beads group but not in the Annexin A1 beads group, confirming that in HCC, GPC3 is preferentially released through exosomes. Furthermore, we found that autophagy induction by Torin1 decreased GPC3-positive exosome secretion and decreased microvesicle release. Conversely, autophagy inhibition by Bafilomycin A1 increased the secretion of GPC3-positive exosomes. Serum analysis showed CD81+ve EVs were detected in exosomes and ARF6+ve vesicles were detected in microvesicles, suggesting that immunoaffinity assay is specific. The exosomal GPC3 enrichment was confirmed in isolated EVs from the serum of patients with HCC. The frequency of GPC3-positive exosomes was higher in patients with HCC (12.4%) compared to exosomes isolated from non-cirrhotic and healthy controls (3.7% and 1.3% respectively, p<0.001). Conclusion: Our results show that GPC3 is enriched in the endolysosomal compartment and released in exosome fractions when autophagy is impaired.

Fatal Gets More Fatal: A COVID-19 Infection With Macrophage Activation Syndrome.

Coronavirus disease 2019 (COVID-19) continues to be fatal despite advances in the understanding of characteristics of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), global prevention strategies, new anti-viral treatments, and worldwide vaccination programs. The exact underlying mechanism through which SARS-CoV-2 leads to acute respiratory distress syndrome (ARDS) resulting in intensive care unit admission, mechanical ventilation, and eventually death remains elusive. Cytokine storm is one of the most favorable mechanisms that scientists show remarkable interest to target in randomized clinical trials with promising outcomes. Macrophage activation syndrome (MAS), the most serious form of cytokine storm, requires early recognition and treatment regardless of etiology. Here, we report a 59-year-old gentleman with a COVID-19 infection complicated by MAS. Our aim is to increase awareness of this condition among health care providers as it necessitates prompt diagnosis and treatment due to an extremely poor prognosis.

The Usual Presentation of an Unusual Case: Spontaneous Primary Splenic Cyst Rupture.

Acute abdominal pain is one of the most common reasons for emergency admissions. Even though initial differentials are wide, a physician is able to narrow them down with detailed history, careful physical examination, and appropriate laboratory tests along with imaging studies. Unfortunately, some of the cases do not have an established diagnosis despite multiple blood work and imaging studies in the emergency department. In such conditions, physicians' recognition of rare diseases generally avoids extra costs for additional investigations, unnecessary consultations, and most importantly wasting valuable time in life-threatening conditions in emergency settings. Here, we report a 30-year-old woman with acute severe abdominal pain and hemodynamic instability who was found to have ascites that was actually hemoperitoneum secondary to spontaneous primary non-parasitic splenic cyst rupture. The primary splenic cyst is an extremely rare entity and is often found on imaging incidentally. A few case reports regarding primary splenic cyst and its complications were published in the literature. Since it is an exceptionally uncommon condition, there is no consensus on treatment. We aimed to increase the understanding of spontaneous primary splenic cyst rupture and its management among healthcare providers with this case report.

Experimental Validation of Novel Glypican 3 Exosomes for the Detection of Hepatocellular Carcinoma in Liver Cirrhosis.

BACKGROUND AND AIMS: Hepatocellular carcinoma (HCC) developing in the context of preexisting cirrhosis is characterized by impaired autophagy that results in increased exosome release. This study was conducted to determine whether circulating exosomes expressing glypican 3 (GPC3) could be utilized as a biomarker for HCC detection and treatment response in patients with cirrhosis. METHODS: Immunohistochemistry was performed to assess p62 and GPC3 expression in the lesion and adjacent tissue from cirrhosis with HCC. GPC3-enriched exosomes were captured by an enzyme-linked immunosorbent assay (ELISA). The diagnostic specificity of serum exosome-derived GPC3 (eGPC3) was determined using samples obtained from malignancy-free controls, malignancy-free cirrhotics, cirrhotics with confirmed HCC, and patients with a non-HCC malignancy. The performance of eGPC3 was validated using serum samples of HCC patients received chemotherapy. RESULTS: We found that the expression of p62 and GPC3 was significantly increased in HCC tissues compared to adjacent cirrhotic liver. Impaired autophagy and exosome shedding were confirmed in HCC cell lines. Mass spectroscopic analysis revealed that GPC3 was enriched in exosomes isolated from HCC cell lines. An affinity ELISA assay was developed that specifically captures GPC3 positive exosomes in the serum. Total exosome concentration and eGPC3 were significantly elevated in cirrhotic patients with HCC as compared to the reference control groups. Furthermore, decreases in post-treatment exosome concentration and eGPC3 levels were more closely correlated with response to locoregional chemotherapy compared to change in serum AFP in HCC patients awaiting liver transplantation. CONCLUSION: We developed an affinity exosome capture assay to detect GPC3 enriched exosomes. Our preliminary assessment shows that GPC3 positive exosomes can be used for HCC detection and prediction of treatment outcomes.

Extracellular Vesicle Release Promotes Viral Replication during Persistent HCV Infection.

Hepatitis C virus (HCV) infection promotes autophagic degradation of viral replicative intermediates for sustaining replication and spread. The excessive activation of autophagy can induce cell death and terminate infection without proper regulation. A prior publication from this laboratory showed that an adaptive cellular response to HCV microbial stress inhibits autophagy through beclin 1 degradation. The mechanisms of how secretory and degradative autophagy are regulated during persistent HCV infection is unknown. This study was performed to understand the mechanisms of viral persistence in the absence of degradative autophagy, which is essential for virus survival. Using HCV infection of a CD63-green fluorescence protein (CD63-GFP), labeled stable transfected Huh-7.5 cell, we found that autophagy induction at the early stage of HCV infection increased the degradation of CD63-GFP that favored virus replication. However, the late-stage of persistent HCV infection showed impaired autophagic degradation, leading to the accumulation of CD63-GFP. We found that impaired autophagic degradation promoted the release of extracellular vesicles and exosomes. The impact of blocking the release of extracellular vesicles (EVs) on virus survival was investigated in persistently infected cells and sub-genomic replicon cells. Our study illustrates that blocking EV and exosome release severely suppresses virus replication without effecting host cell viability. Furthermore, we found that blocking EV release triggers interferon lambda 1 secretion. These findings suggest that the release of EVs is an innate immune escape mechanism that promotes persistent HCV infection. We propose that inhibition of extracellular vesicle release can be explored as a potential antiviral strategy for the treatment of HCV and other emerging RNA viruses.

Additional Inhibition of Wnt/ß-Catenin Signaling by Metformin in DAA Treatments as a Novel Therapeutic Strategy for HCV-Infected Patients.

Chronic hepatitis C virus (HCV) infection causes hepatocellular carcinoma (HCC). Although HCV clearance has been improved by the advent of direct-acting antiviral agents (DAA), retrospective studies have shown that the risk of subsequent HCC, while considerably decreased compared with active HCV infection, persists after DAA regimens. However, either the mechanisms of how chronic HCV infection causes HCC or the factors responsible for HCC development after viral eradication in patients with DAA treatments remain elusive. We reported an in vitro model of chronic HCV infection and determined Wnt/ß-catenin signaling activation due to the inhibition of GSK-3ß activity via serine 9 phosphorylation (p-ser9-GSK-3ß) leading to stable non-phosphorylated ß-catenin. Immunohistochemical staining demonstrated the upregulation of both ß-catenin and p-Ser9-GSK-3ß in HCV-induced HCC tissues. Chronic HCV infection increased proliferation and colony-forming ability, but knockdown of ß-catenin decreased proliferation and increased apoptosis. Unexpectedly, Wnt/ß-catenin signaling remained activated in chronic HCV-infected cells after HCV eradication by DAA, but metformin reversed it through PKA/GSK-3ß-mediated ß-catenin degradation, inhibited colony-forming ability and proliferation, and increased apoptosis, suggesting that DAA therapy in combination with metformin may be a novel therapy to treat HCV-associated HCC where metformin suppresses Wnt/ß-catenin signaling for HCV-infected patients.

Hepatocellular Carcinoma Mechanisms Associated with Chronic HCV Infection and the Impact of Direct-Acting Antiviral Treatment.

Hepatitis C virus (HCV) infection is the major risk factor for liver cirrhosis and hepatocellular carcinoma (HCC). The mechanisms of HCC initiation, growth, and metastasis appear to be highly complex due to the decade-long interactions between the virus, immune system, and overlapping bystander effects of host metabolic liver disease. The lack of a readily accessible animal model system for HCV is a significant obstacle to understand the mechanisms of viral carcinogenesis. Traditionally, the primary prevention strategy of HCC has been to eliminate infection by antiviral therapy. The success of virus elimination by antiviral treatment is determined by the SVR when the HCV is no longer detectable in serum. Interferon-alpha (IFN-α) and its analogs, pegylated IFN-α (PEG-IFN-α) alone with ribavirin (RBV), have been the primary antiviral treatment of HCV for many years with a low cure rate. The cloning and sequencing of HCV have allowed the development of cell culture models, which accelerated antiviral drug discovery. It resulted in the selection of highly effective direct-acting antiviral (DAA)-based combination therapy that now offers incredible success in curing HCV infection in more than 95% of all patients, including those with cirrhosis. However, several emerging recent publications claim that patients who have liver cirrhosis at the time of DAAs treatment face the risk of HCC occurrence and recurrence after viral cure. This remains a substantial challenge while addressing the long-term benefit of antiviral medicine. The host-related mechanisms that drive the risk of HCC in the absence of the virus are unknown. This review describes the multifaceted mechanisms that create a tumorigenic environment during chronic HCV infection. In addition to the potential oncogenic programming that drives HCC after viral clearance by DAAs, the current status of a biomarker development for early prediction of cirrhosis regression and HCC detection post viral treatment is discussed. Since DAAs treatment does not provide full protection against reinfection or viral transmission to other individuals, the recent studies for a vaccine development are also reviewed.

Integrated stress response in hepatitis C promotes Nrf2-related chaperone-mediated autophagy: A novel mechanism for host-microbe survival and HCC development in liver cirrhosis.

The molecular mechanism(s) how liver damage during the chronic hepatitis C virus (HCV) infection evolve into cirrhosis and hepatocellular carcinoma (HCC) is unclear. HCV infects hepatocyte, the major cell types in the liver. During infection, large amounts of viral proteins and RNA replication intermediates accumulate in the endoplasmic reticulum (ER) of the infected hepatocyte, which creates a substantial amount of stress response. Infected hepatocyte activates a different type of stress adaptive mechanisms such as unfolded protein response (UPR), antioxidant response (AR), and the integrated stress response (ISR) to promote virus-host cell survival. The hepatic stress is also amplified by another layer of innate and inflammatory response associated with cellular sensing of virus infection through the production of interferon (IFN) and inflammatory cytokines. The interplay between various types of cellular stress signal leads to different forms of cell death such as apoptosis, necrosis, and autophagy depending on the intensity of the stress and nature of the adaptive cellular response. How do the adaptive cellular responses decode such death programs that promote host-microbe survival leading to the establishment of chronic liver disease? In this review, we discuss how the adaptive cellular response through the Nrf2 pathway that promotes virus and cell survival. Furthermore, we provide a glimpse of novel stress-induced Nrf2 mediated compensatory autophagy mechanisms in virus-cell survival that degrade tumor suppressor gene and activation of oncogenic signaling during HCV infection. Based on these facts, we hypothesize that the balance between hepatic stress, inflammation and different types of cell death determines liver disease progression outcomes. We propose that a more nuanced understanding of virus-host interactions under excessive cellular stress may provide an answer to the fundamental questions why some individuals with chronic HCV infection remain at risk of developing cirrhosis, cancer and some do not.

Amphiphilic Polypeptoids Rupture Vesicle Bilayers To Form Peptoid-Lipid Fragments Effective in Enhancing Hydrophobic Drug Delivery.

Peptoids are highly biocompatible pseudopeptidic polyglycines with designable substituents on the nitrogen atoms. The therapeutic and drug-carrying potential of these materials requires a fundamental understanding of their interactions with lipid bilayers. In this work, we use amphiphilic polypeptoids with up to 100 monomeric units where a significant fraction (26%) of the nitrogen atoms are functionalized with decyl groups (hydrophobes) that insert into the lipid bilayer through the hydrophobic effect. These hydrophobically modified polypeptoids (HMPs) insert their hydrophobes into lipid bilayers creating instabilities that lead to the rupture of vesicles. At low HMP concentrations, such rupture leads to the creation of large fragments which remarkably anchor to intact vesicles through the hydrophobic effect. At high HMP concentrations, all vesicles rupture to smaller HMP-lipid fragments of the order of 10 nm. We show that the technique for such nanoscale polymer-lipid fragments can be exploited to sustain highly hydrophobic drug species in solution. Using the kinase inhibitor, Sorafenib as a model drug, it is shown that HMP-lipid fragments containing the drug can efficiently enter a hepatocellular carcinoma cell line (Huh 7.5), indicating the use of such fragments as drug delivery nanocarriers.

Chaperone-Mediated Autophagy in the Liver: Good or Bad?

Hepatitis C virus (HCV) infection triggers autophagy processes, which help clear out the dysfunctional viral and cellular components that would otherwise inhibit the virus replication. Increased cellular autophagy may kill the infected cell and terminate the infection without proper regulation. The mechanism of autophagy regulation during liver disease progression in HCV infection is unclear. The autophagy research has gained a lot of attention recently since autophagy impairment is associated with the development of hepatocellular carcinoma (HCC). Macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA) are three autophagy processes involved in the lysosomal degradation and extracellular release of cytosolic cargoes under excessive stress. Autophagy processes compensate for each other during extreme endoplasmic reticulum (ER) stress to promote host and microbe survival as well as HCC development in the highly stressed microenvironment of the cirrhotic liver. This review describes the molecular details of how excessive cellular stress generated during HCV infection activates CMA to improve cell survival. The pathological implications of stress-related CMA activation resulting in the loss of hepatic innate immunity and tumor suppressors, which are most often observed among cirrhotic patients with HCC, are discussed. The oncogenic cell programming through autophagy regulation initiated by a cytoplasmic virus may facilitate our understanding of HCC mechanisms related to non-viral etiologies and metabolic conditions such as uncontrolled type II diabetes. We propose that a better understanding of how excessive cellular stress leads to cancer through autophagy modulation may allow therapeutic development and early detection of HCC.

Hepatic Stress Response in HCV Infection Promotes STAT3-Mediated Inhibition of HNF4A-miR-122 Feedback Loop in Liver Fibrosis and Cancer Progression.

Hepatitis C virus (HCV) infection compromises the natural defense mechanisms of the liver leading to a progressive end stage disease such as cirrhosis and hepatocellular carcinoma (HCC). The hepatic stress response generated due to viral replication in the endoplasmic reticulum (ER) undergoes a stepwise transition from adaptive to pro-survival signaling to improve host cell survival and liver disease progression. The minute details of hepatic pro-survival unfolded protein response (UPR) signaling that contribute to HCC development in cirrhosis are unknown. This study shows that the UPR sensor, the protein kinase RNA-like ER kinase (PERK), mediates the pro-survival signaling through nuclear factor erythroid 2-related factor 2 (NRF2)-mediated signal transducer and activator of transcription 3 (STAT3) activation in a persistent HCV infection model of Huh-7.5 liver cells. The NRF2-mediated STAT3 activation in persistently infected HCV cell culture model resulted in the decreased expression of hepatocyte nuclear factor 4 alpha (HNF4A), a major liver-specific transcription factor. The stress-induced inhibition of HNF4A expression resulted in a significant reduction of liver-specific microRNA-122 (miR-122) transcription. It was found that the reversal of hepatic adaptive pro-survival signaling and restoration of miR-122 level was more efficient by interferon (IFN)-based antiviral treatment than direct-acting antivirals (DAAs). To test whether miR-122 levels could be utilized as a biomarker of hepatic adaptive stress response in HCV infection, serum miR-122 level was measured among healthy controls, and chronic HCV patients with or without cirrhosis. Our data show that serum miR-122 expression level remained undetectable in most of the patients with cirrhosis (stage IV fibrosis), suggesting that the pro-survival UPR signaling increases the risk of HCC through STAT3-mediated suppression of miR-122. In conclusion, our data indicate that hepatic pro-survival UPR signaling suppresses the liver-specific HNF4A and its downstream target miR-122 in cirrhosis. These results provide an explanation as to why cirrhosis is a risk factor for the development of HCC in chronic HCV infection.