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The effect of aerobic glycolysis remains elusive in pediatric acute T lymphoblastic leukemia (T-ALL). Increasing evidence has revealed that dysregulation of deubiquitination is involved in glycolysis, by targeting glycolytic rate-limiting enzymes. Here, we demonstrated that upregulated deubiquitinase USP1 expression correlated with poor prognosis in pediatric primary T-ALL samples. USP1 depletion abolished cellular proliferation and attenuated glycolytic metabolism. In vivo experiments showed that USP1 suppression decreased leukemia progression in nude mice. Inhibition of USP1 caused a decrease of both mRNA and protein levels in LDHA, a critical glycolytic enzyme. Moreover, USP1 interacted with and deubiquitinated PLK1, a critical regulator of glycolysis. Overexpression of USP1 with upregulated PLK1 was observed in most T-ALL patient samples. In addition, PLK1 inhibition reduced LDHA expression and abrogated the USP1-mediated increase of cell proliferation and lactate level. Ectopic expression of LDHA can rescue the suppressive effect of USP1 silencing on cell growth and lactate production. Pharmacological inhibition of USP1 by ML323 exhibited cell cytotoxicity in human T-ALL cells. Taken together, our results demonstrated that USP1 may be a promising therapeutic target in pediatric T-ALL.

Myristic acid-palmitic acid-tetradecanol/expanded graphite (MA-PA-TD/EG) and myristic acid-stearic acid-lauric acid/ expanded graphite (MA-SA-LA/EG) were obtained. MA-PA-TD/EG and MA-SA-LA/EG for the optimum mass ratio of 8:1 were investigated by DSC, FT-IR, TG, and SEM, and it was shown that MA-PA-TD and MA-SA-LA phase change materials were evenly distributed in expanded graphite through capillary force. Phase transition temperatures of MA-PA-TD/EG and MA-SA-LA/EG before and after cooling and heating cycles were 34.14, 34.39 °C and 30.21, 30.33 °C, respectively, and MA-PA-TD/EG and MA-SA-LA/EG had good stability. On the other hand, MA-PA-TD/EG was 67% faster than that of MA-PA-TD during solid-liquid phase change, and MA-SA-LA/EG was 63% faster than that of MA-SA-LA. Meanwhile, MA-PA-TD/EG and MA-SA-LA/EG had good thermal stability and heat storage according to thermogravimetric experiments. Therefore, MA-PA-TD/EG and MA-SA-LA/EG are suitable for practical application in buildings.

PURPOSE Arsenic combined with all-trans retinoic acid (ATRA) is the standard of care for adult acute promyelocytic leukemia (APL). However, the safety and effectiveness of this treatment in pediatric patients with APL have not been reported on the basis of larger sample sizes. METHODS We conducted a multicenter trial at 38 hospitals in China. Patients with newly diagnosed APL were stratified into two risk groups according to baseline WBC count and FLT3-ITD mutation. ATRA plus arsenic trioxide or oral arsenic without chemotherapy were administered to the standard-risk group, whereas ATRA, arsenic trioxide, or oral arsenic plus reduced-dose anthracycline were administered to the high-risk group. Primary end points were event-free survival and overall survival at 2 years. RESULTS We enrolled 193 patients with APL. After a median follow-up of 28.9 months, the 2-year overall survival rate was 99% (95% CI, 97 to 100) in the standard-risk group and 95% (95% CI, 90 to 100) in the high-risk group ( P = .088). The 2-year event-free survival was 97% (95% CI, 93 to 100) in the standard-risk group and 90% (95% CI, 83 to 96) in the high-risk group ( P = .252). The plasma levels of arsenic were significantly elevated after treatment, with a stable effective level ranging from 42.9 to 63.2 ng/mL during treatment. In addition, plasma, urine, hair, and nail arsenic levels rapidly decreased to normal 6 months after the end of treatment. CONCLUSION Arsenic combined with ATRA is effective and safe in pediatric patients with APL, although long-term follow-up is still needed.

Wnt signaling plays an important role in embryonic development and tumorigenesis. These biological effects are exerted by activation of the β-catenin/TCF transcription complex and consequent regulation of a set of downstream genes. Dickkopf WNT Signaling Pathway Inhibitor 1 (DKK1) has been shown to be a potent inhibitor of Wnt signaling via competing Wnt binding to LRP5/6. DKK1 is tumorigenic in multiple cancer types and also immunosuppressive via MDSCs and NK cells. Emerging evidence indicates that DKK1 has been involved in T cell differentiation and induction of cancer evasion of immune surveillance by accumulating MDSCs. Consequently, DKK1 has become a promising target for cancer immunotherapy, and the mechanisms of DKK1 affecting cancers and immune cells have received great attention. With Twist’s precision DNA writing technologies, we have created phage display libraries with diversity greater than 1 × 1010, and utilized machine learning model for optimal discovery. In this study, we discovered anti-DKK1 antibodies blocking the binding of DKK1 to the receptor. The in vitro functional assays showed that the interaction of Wnt to its receptor was restored in the presence of anti-DKK1 antibodies, resulting in TCF/LEF signaling upregulation. Moreover, anti-DKK1 antibodies induced immune cell activation, and led to tumor cell cytotoxicity. In addition, anti-DKK1 antibodies binding to different domains of DKK1 led to different functional effect. In vivo study indicated anti-DKK1 antibodies is potent in tumor regression. Our anti-DKK1 leads shows promising efficacy in cancer immunotherapy. Citation Format: Linya Wang, Sean M. Peterson, Ana Lujan, Kara Y. Chan, Cameron F. Hu, Mouna Villalta, Tom Z. Yuan, Zhen Han, Marisa Yang, Vishwas Prabhu, Tammy Htoy, Paul VanDyke, Carson Holliday, Hector Franco, Hansika Wadhwa, Hoa Giang, Ryan Stafford, Fumiko Axelrod, Aaron Sato. Discovery of a potent, selective, and tumor-suppressing antibody antagonist of DKK1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2649.

Checkpoint inhibitors represent a major advance in cancer immunotherapy, and combinatorial immunotherapies with secondary drivers of anti-tumor immunity provide beneficial effects for patients that do not show a strong endogenous immune response. CD40 is a member of the TNF family of receptors that has been shown to play a crucial role in enhancing B cell and dendritic cell activity and fostering anti-tumor immune responses. Engagement of the inhibitory Fcg-receptor (FcgR) IIb is an absolute requirement for in vivo antitumor activity of agonistic anti-CD40 monoclonal antibodies, and Fc region mutant designs of anti-CD40 antibodies had been discovered to enhance FcgRIIb engagement. With Twist’s precision DNA writing technologies, we have created phage display VHH and scFv libraries with diversity greater than 1 × 1010 for optimal discovery. In this study, we performed high affinity binding of the antibodies by SPR and cell surface binding. The leads are reformatted on human IgG1, IgG4, and IgG1 mutant. The in vitro properties of the CD40 agonistic antibodies demonstrate enhanced FcgRIIb engagement by NFkB activation. B cell activation is also detected by upregulation of CD86 and IL6 secretion. In humanized hCD40 mice model, we observed the engineered anti-CD40 agonists enhance anti-tumor immune function in vivo. These studies suggest that our antibodies can be potential drug for cancer immunotherapy. Citation Format: Linya Wang, Tom Z. Yuan, Mouna Villalta, Zhen Han, Hansika Wadhwa, Kara Y. Chan, Marisa Yang, Tammy Htoy, Paul VanDyke, Carson Holliday, Hector Franco, Hoa Giang, Fumiko Axelrod, Aaron Sato. Human anti-CD40 agonistic antibodies with enhanced FcgR engagement activate immune cell and promote anti-tumor efficacy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1531.

Energy has become the key material basis of social development. In this work, liquid capric acid-paraffin was evenly adsorbed in the pore structure of expanded graphite (EG) by a physical adsorption method, and the new composite phase change material of capric acid-paraffin/expanded graphite (CA-P/EG) was prepared. The Fourier transform infrared (FT-IR) curves of CA-P/EG composites did not change after 1000 cycles, and there was no new characteristic absorption peak, indicating that CA-P/EG composites have good chemical stability. The results showed that the optimum content of CA-P/EG in a phase change energy storage gypsum board was 20%, and the wet bending strength and compressive strength were 2.42 and 6.45 MPa, respectively. The water absorption was 16.37%, and the apparent density was 1.410 g/cm3. In addition, the melting and freezing temperatures were 26.40 and 23.10 °C, and the latent heats of melting and freezing were 27.20 and 25.69 J/g, respectively. It was found that the gypsum board has excellent thermal stability after 400 times of melting–freezing cycling and that the heat storage capacity increases with the increase of the CA-P/EG content and the thickness of the gypsum board.

Two kinds of CA–SA-based ternary phase change materials (PCMs), namely, capric acid–stearic acid–palmitic acid (CA–SA–PA) and capric acid–stearic acid–octadecanol (CA–SA–OD), were prepared by the melting–blending method. By the step cooling curve method, the optimum mass ratio of the two PCMs were determined to be CA : SA : PA = 77.4 : 8.6 : 14.0 and CA : SA : OD = 81.9 : 9.1 : 9.0, and the crystallization temperatures were 19.20 °C and 23.90 °C, respectively. The phase transition temperatures as measured by DSC were 18.60 °C and 24.82 °C, and the latent heat of phase transition were 129.15 J g−1 and 161.74 J g−1, respectively. The results are in good agreement with those measured by the step cooling curve method. The chemical and crystalline properties of the two PCMs were analyzed by FT-IR and XRD. It was found that CA–SA is combined with PA or OD by physical action, and the components have good compatibility and form a good eutectic structure. In addition, the results of heat storage and heat release experiments and the 500 times of accelerated melting–solidification cycling test showed that the two kinds of PCMs have good heat resistance and thermal reliability. Therefore, the prepared CA–SA–PA and CA–SA–OD have good performance and great application potential in building energy saving and solar energy utilization.

Arsenic trioxide (ATO) has been found to be effective in acute promyelocytic leukemia. However, ATO-induced severe cardiotoxicity limits its clinical application. To date, the mechanisms of ATO-induced cardiotoxicity remain unclear. It is hypothesized that ferroptosis may trigger ATO-induced cardiotoxicity; however, this has not yet been investigated. To clarify this hypothesis, rat cardiomyocyte H9c2 cells were treated with ATO with or without ferrostain-1 (Fer-1). The results indicated that ATO exposure induced H9c2 cell death and apoptosis, and the ferroptosis inhibitor Fer-1, administered for 24 h before ATO exposure, suppressed ATO-induced cell death, and apoptosis, as determined by Annexin V-APC/7-AAD apoptosis assay. Furthermore, Fer-1 displayed a cardioprotective effect through inhibiting the ATO-induced production of intracellular reactive oxygen species, improving the ATO-induced loss of the mitochondrial membrane potential, alleviating hyperactive endoplasmic reticulum stress, and alleviating the ATO-induced impairment in autophagy in H9c2 cells. Overall, the cardioprotective effect of Fer-1 against ATO-induced cell injury implies that ATO may trigger ferroptosis to induce cardiotoxicity. These findings lay the foundation for exploring the potential value of ferroptosis inhibitors against ATO-induced cardiotoxicity in the future.

Coronavirus disease 2019 (COVID-19) is an evolving global public health crisis in need of therapeutic options. Passive immunization of monoclonal antibodies (mAbs) represents a promising therapeutic strategy capable of conferring immediate protection from SARS-CoV-2 infection. Herein, we describe the discovery and characterization of neutralizing SARS-CoV-2 IgG and VHH antibodies from four large-scale phage libraries. Each library was constructed synthetically with shuffled complementarity-determining region loops from natural llama and human antibody repertoires. While most candidates targeted the receptor-binding domain of the S1 subunit of SARS-CoV-2 spike protein, we also identified a neutralizing IgG candidate that binds a unique epitope on the N-terminal domain. A select number of antibodies retained binding to SARS-CoV-2 variants Alpha, Beta, Gamma, Kappa and Delta. Overall, our data show that synthetic phage libraries can rapidly yield SARS-CoV-2 S1 antibodies with therapeutically desirable features, including high affinity, unique binding sites, and potent neutralizing activity in vitro, and a capacity to limit disease in vivo.

Summary A minority of hand, foot and mouth disease (HFMD) caused by enterovirus A71 (EV-A71) results in severe neural complications. However, whether monocyte-mediated immunity is involved in the disease progression of HFMD remains unknown. One hundred and twenty mild and 103 severe HFMD patients were recruited and enzyme-linked immunosorbent assay (ELISA), flow cytometry and Transwell culture were performed in the study. Peripheral monocyte counts were lower in both absolute counts and frequencies in severe cases compared to mild cases. After screening 10 monocyte-related cytokines by ELISA, only monocyte chemoattractant protein-1 (MCP-1) was found at higher levels in sera of mild cases compared to those with severe symptoms. Monocytes purified from mild cases produced more MCP-1 than the cells from severe patients when stimulated in vitro. We observed that immune exhaustion markers programmed death 1 (PD-1) and programmed death ligand 1 (PD-L1) were highly regulated on the surface of monocytes from severe cases compared to mild cases. PD-L1 blockade induced a higher production of MCP-1 in the supernatant of a Transwell system. The production of MCP-1 also increased following PD-L1 blockade of purified monocytes activated by granulocyte–macrophage colony-stimulating factor (GM-CSF) combined with R848 or EV-A71 virus. Our results indicate that absolute count, frequency and levels of MCP-1 secretion of peripheral monocytes, together with their immune status, probably contribute to differential disease prognosis in EV-A71-associated HFMD.

With the rapid development of urbanization, cities need more external resources to meet their ultimate demand, which leads to the transfer of land use function between urban and rural areas. How to measure the urban–rural land use coupling remains to be studied. In addition, due to the difficulty in evaluating the unequal development and coupling between urban and rural areas, resource-consuming regions often evade their responsibility for environmental pollution, resulting in unfair allocation of invested resources. Therefore, a framework for the allocation of resources invested in ecological governance was built from the perspective of urban–rural land use coupling. This framework made clear the urban–rural coupling and applied Gini coefficient to judge the overall imbalance in the region. According to the unbalanced structure of the region, the allocation framework based on the location quotient was used to redistribute the resources invested in ecological governance, and the attribution of responsibility was made clear, which can promote regional fairness. The main conclusions are: (I) Taiwan’s overall urban–rural coupling is 8.3, that is, every hectare of land development in Taiwan requires 8.30 hectares of ecological land to meet development needs. The urban area needs to rely heavily on the ecological resources provided by the rural area. (II) The environmental problems of the urban area need to be solved by the urban area itself, while the rural area requires the urban area to be responsible for its ecological governance, and it needs to be responsible for the resource consumption of the external systems. This research provides a new perspective for the research on urban–rural coupling and resource allocation.

A new composite phase change material of capric acid-palmitic acid/expanded graphite (CA-PA/EG) with the optimum mass ratio of EG equated to 8:1 was prepared by the physical adsorption method. It was observed that the eutectic point of CA-PA binary system was reached at 22.1 °C, and CA-PA was uniformly distributed into the pores of EG by physical interaction. The melting and freezing temperatures of CA-PA/EG obtained by differential scanning calorimeter (DSC) were 23.05 and 20.82 °C, respectively, while the corresponding latent heats were 139.7 and 131.8 J/g, respectively. It had good thermal and chemical stability, and there was almost no leakage of liquid binary phase change materials after 1000 melting-freezing cycles. According to the experimental results of the thermogravimetry (TG) analyzer as well as heat storage and release, CA-PA/EG has excellent thermal reliability and heat resistance and the high thermal conductivity of EG promotes the thermal energy storage and release rate of CA-PA. Thus, CA-PA/EG is suitable as a phase change energy storage material for building energy conservation.

Summary Antibody levels after hepatitis B virus (HBV) vaccination may be affected by suppression of the immune system due to cancer therapy. As such, childhood acute lymphocytic leukaemia (ALL) survivors are at risk of HBV infection due to immunosuppression secondary to chemotherapy. However, the hepatitis B surface antibody (HBsAb)-seropositive rate of childhood ALL survivors after chemotherapy is unknown, and the need to revaccinate HBsAb-seronegative ALL survivors is not appreciated in China. To assess the changes in HBsAb before and after chemotherapy, we retrospectively analyzed clinical data from 547 patients treated with the Chinese Children Leukaemia Group (CCLG)-ALL 2008 protocol from 1 April 2008 to 30 August 2019. The results revealed that 416 patients (76·1%) were HBsAb-seropositive at diagnosis, and at the time of the cessation of chemotherapy, 177 patients (32·4%) were HBsAb-seropositive and 370 patients (67·6%) were HBsAb-seronegative. Interestingly, 11 patients who were HBsAb-seronegative at diagnosis converted to seropositive at the time of the cessation of chemotherapy. HBsAb titres were decreased after chemotherapy (P

In recent years, outbreaks of hand–foot–mouth disease (HFMD) in China, Singapore and other Western Pacific Region, involving millions of children, have become a big threat to public health. This study aimed to quantitatively assess all qualified studies and identify the risk factors for HFMD death. A systematic search of the databases PubMed, Medline, Embase and the Cochrane Library was performed. Study heterogeneity and publication bias were estimated. Seven case–control studies involving 1641 participants (634 died and 1007 survived) were included in the meta-analysis. Human enterovirus 71 infection, male, age ⩽3 years, vomiting, cyanosis, convulsion, duration of fever ⩾3 days, atypical rashes and abdominal distention were not significantly related to HFMD death (P⩽ 0.05). Lethargy (odds ratio (OR) = 6.62; 95% CI 3.61–12.14;I2= 0%;P< 0.0001), pneumonoedema/pneumorrhagia (OR = 4.09; 95% CI 2.44–6.87;I2= 0%;P< 0.0001), seizures (OR = 6.85; 95% CI 2.37–19.74;I2= 0%;P= 0.0004), dyspnoea (OR = 8.24; 95% CI 2.05–33.19;I2= 83%;P= 0.003) and coma (OR = 3.76; 95% CI 1.85–7.67;I2= 0%;P= 0.0003) were significantly associated with HFMD death, which were risk factors for HFMD death.

Macroautophagy, hereafter autophagy, is a catabolic process that is important for maintaining cellular homeostasis. It can also be used by cells to remove intracellular microbial pathogens. However, the studies on hepatitis C virus (HCV) in recent years indicated that this virus could regulate this cellular pathway and use it to enhance its replication. HCV could temporally control the autophagic flux and use the autophagic membranes for the assembly of its RNA replication complex. In this report, we will discuss the biogenesis of autophagosomes induced by HCV and how HCV uses this autophagic pathway for its RNA replication.

Autophagy plays an important role in maintaining cellular homeostasis. Its dysfunction can cause many diseases, including neurodegenerative diseases, metabolic diseases and cancer. The role of autophagy in carcinogenesis is complex, as it was shown to have pro-tumorigenic functions in some reports, but anti-tumorigenic functions in others. By using mice with hepatocyte-specific knockout of Atg5, a gene essential for autophagy, we had previously demonstrated that impairing autophagy in hepatocytes would induce oxidative stress and DNA damage, followed by the initiation of hepatocarcinogenesis. Interestingly, these mice developed only benign tumors with no hepatocellular carcinoma (HCC), even after they were treated with the carcinogen diethylnitrosamine (DEN), which induced HCC in wild-type mice. Our recent studies indicated that the inability of mice to develop HCC when autophagy was impaired was at least partially due to the activation of the tumor suppressor TP53, which suppressed the expression of NANOG, a transcription factor critical for the self-renewal and the maintenance of cancer stem cells (CSCs).

Autophagy is a catabolic process by which cells remove protein aggregates and damaged organelles for recycling. It can also be used by cells to remove intracellular microbial pathogens, including viruses, in a process known as xenophagy. However, many viruses have developed mechanisms to subvert this intracellular antiviral response and even use this pathway to support their own replications. Hepatitis C virus (HCV) is one such virus and is an important human pathogen that can cause severe liver diseases. Recent studies indicated that HCV could activate the autophagic pathway to support its replication. This review summarizes the current knowledge on the interplay between HCV and autophagy and how this interplay affects HCV replication and host innate immune responses.

Autophagy plays an important role in maintaining cellular homeostasis. Its dysfunction can cause many diseases, including neurodegenerative diseases, metabolic diseases and cancer. The role of autophagy in carcinogenesis is complex, as it was shown to have pro-tumorigenic functions in some reports, but anti-tumorigenic functions in others. By using mice with hepatocyte-specific knockout of Atg5, a gene essential for autophagy, we had previously demonstrated that impairing autophagy in hepatocytes would induce oxidative stress and DNA damage, followed by the initiation of hepatocarcinogenesis. Interestingly, these mice developed only benign tumors with no hepatocellular carcinoma (HCC), even after they were treated with the carcinogen diethylnitrosamine (DEN), which induced HCC in wild-type mice. Our recent studies indicated that the inability of mice to develop HCC when autophagy was impaired was at least partially due to the activation of the tumor suppressor TP53, which suppressed the expression of NANOG, a transcription factor critical for the self-renewal and the maintenance of cancer stem cells (CSCs).

The role of autophagy in carcinogenesis is controversial and apparently complex. By using mice with hepatocyte-specific knockout of Atg5, a gene essential for autophagy, we longitudinally studied the role of autophagy in hepatocarcinogenesis. We found that impairing autophagy in hepatocytes would induce oxidative stress and DNA damage, followed by the initiation of hepatocarcinogenesis, which could be suppressed by the antioxidant N-acetylcysteine. Interestingly, these mice developed only benign tumors with no hepatocellular carcinoma (HCC), even after the treatment with diethylnitrosamine, which induced HCC in wild-type mice. The inability of mice to develop HCC when autophagy was impaired was associated with the induction of multiple tumor suppressors including p53. Further analysis indicated that the induction of p53 was associated with the DNA-damage response. Tumorigenesis studies using an established liver tumor cell line confirmed a positive role of autophagy in tumorigenesis and a negative role of p53 in this process when autophagy was impaired. Our studies thus demonstrate that autophagy is required to maintain healthy mitochondria and to reduce oxidative stress and DNA damage to prevent the initiation of hepatocarcinogenesis. However, once hepatocarcinogenesis has been initiated, its presence is also required to suppress the expression of tumor suppressors to promote the development of HCC.

Objective Intravenous arsenic trioxide (ATO) and all-trans retinoic acid have become the front-line treatments for patients with acute promyelocytic leukemia (APL). Realgar-Indigo naturalis formula (RIF), an oral arsenic drug, not only shows a clinical efficacy comparable to ATO but also promotes incorporating an outpatient postremission therapy model into clinical practice for both low-risk and high-risk APL patients in China. However, the safety of ATO/RIF used in children with APL is unknown. To assess the safety of arsenic (ATO/RIF) administrated in children with APL, we designed the study. Methods Children with newly diagnosed APL treated with CCLG-APL2016 protocol (ChiCTR-OIN-17011227) in Beijing Children's Hospital from July 2016 to December 2018 were eligible for the study. The arsenic concentrations in different tissues, including plasma, urine, hair and nail, were measured at 10 time points: before ATO/RIF(D0), on the 7th, 14th and 28th day of ATO/RIF administration(D7, D14, D28), on the end of consolidation therapy (Con), during the 10 weeks of maintenance therapy (W10), on the cessation of therapy, after six months, one year and 1.5 years without arsenic administration. Adverse reactions were observed to evaluate the safety of arsenic received in children with APL. Results Nineteen patients with newly diagnosed APL were enrolled, including 9 boys and 7 girls with an onset average age of (10.9±3.7) years. There were 14 patients in low-risk group (white cell count Conclusions Through the detection of arsenic concentration in different periods and different tissues, it was found that the plasma arsenic concentration could be maintained within the effective concentration range in each treatment stage, and the arsenic concentration in plasma and hair gradually decreased to normal after six months off arsenic. Urine and nail arsenic went down to normal after 1 year off arsenic. Up to now, with a longest follow-up period of 34.7 months and the mean follow-up time of 19.6 months, the short-term response of arsenic disappeared after symptomatic therapy or arsenic reduction, and no chronic side effects of arsenic were observed. Therefore, the use of ATO/RIF in children with APL is safe, but it still needs long-term follow-up. Disclosures No relevant conflicts of interest to declare.

Sequences in the 5′ untranslated region (5′UTR) of hepatitis C virus (HCV) RNA is important for modulating both translation and RNA replication. The translation of the HCV genome depends on an internal ribosome entry site (IRES) located within the 341-nucleotide 5′UTR, while RNA replication requires a smaller region. A question arises whether the replication and translation functions require different regions of the 5′UTR and different sets of RNA-binding proteins. Here, we showed that the 5′-most 157 nucleotides of HCV RNA is the minimum 5′UTR for RNA replication, and it partially overlaps with the IRES. Stem-loops 1 and 2 of the 5′UTR are essential for RNA replication, whereas stem-loop 1 is not required for translation. We also found that poly(C)-binding protein 2 (PCBP2) bound to the replication region of the 5′UTR and associated with detergent-resistant membrane fractions, which are the sites of the HCV replication complex. The knockdown of PCBP2 by short hairpin RNA decreased the amounts of HCV RNA and nonstructural proteins. Antibody-mediated blocking of PCBP2 reduced HCV RNA replication in vitro , indicating that PCBP2 is directly involved in HCV RNA replication. Furthermore, PCBP2 knockdown reduced IRES-dependent translation preferentially from a dual reporter plasmid, suggesting that PCBP2 also regulated IRES activity. These findings indicate that PCBP2 participates in both HCV RNA replication and translation. Moreover, PCBP2 interacts with HCV 5′- and 3′UTR RNA fragments to form an RNA-protein complex and induces the circularization of HCV RNA, as revealed by electron microscopy. This study thus demonstrates the mechanism of the participation of PCBP2 in HCV translation and replication and provides physical evidence for HCV RNA circularization through 5′- and 3′UTR interaction.

Autophagy has opposite effects on hepatocarcinogenesis depending on whether it occurs before or after its onset. Autophagy prevents the initiation of hepatocarcinogenesis by suppressing oxidative stress and DNA damage. However, it also inhibits cell death and the expression of tumor suppressors to promote tumor progression once hepatocarcinogenesis has been initiated.