Kaposi's sarcoma-associated herpesvirus-positive primary effusion lymphoma tumor formation in NOD/SCID mice is inhibited by neomycin and neamine blocking angiogenin's nuclear translocation

Antiviral/antibacterial biodegradable cellulose nonwovens as environmentally friendly and bioprotective materials with potential to minimize microplastic pollution

Personal protective equipment (PPE) such as face masks is vital in battling the COVID-19 crisis, but the dominant polypropylene-based PPE are lack of antiviral/antibacterial activities and environmental friendliness, and have hazardous impact on the soil and aquatic ecosystems. The work presented herein focused on developing biodegradable, antiviral, and antibacterial cellulose nonwovens (AVAB-CNWs) as a multi-functional bioprotective layer for better protection against coronavirus SARS-CoV-2 and addressing environmental concerns raised by the piling of COVID-19 related wastes. Both guanidine-based polymer and neomycin sulfate (NEO) were reactive-modified and covalently grafted onto the surface of cellulose nonwovens, thereby conferring outstanding antiviral and antibacterial activities to the nonwovens without deteriorating the microstructure and biodegradability. Through adjusting the grafting amount of active components and selecting appropriate reagents for pretreatment, the antimicrobial activity and hydrophobicity for self-cleaning of the nonwovens can be tuned. More importantly, we demonstrated for the first time that such multi-functional nonwovens are capable of inactivating SARS-CoV-2 instantly, leading to high virucidal activity (> 99.35%), which is unachievable by conventional masks used nowadays. Meanwhile, the robust breathability and biodegradability of AVAB-CNWs were well maintained. The applications of the as-prepared nonwovens as high-performance textile can be readily extended to other areas in the fight against COVID-19.

Primaquine as a Candidate for HHV-8-Associated Primary Effusion Lymphoma and Kaposi’s Sarcoma Treatment

Simple Summary

Primaquine diphosphate is introduced as a promising therapeutic candidate for HHV-8-associated diseases by inducing specific cytotoxicity in vitro through ROS- and ER stress-mediated apoptosis. PQ presented a promising anti-tumor effect in an in vivo PEL mouse model and in KS patients within a pilot clinical study.

Abstract

Human Herpesvirus 8 (HHV-8) is associated with three main severe orphan malignancies, Kaposi’s sarcoma (KS), multicentric Castleman’s disease (MCD), and primary effusion lymphoma (PEL), which present few therapeutic options. We identified the antimalarial primaquine diphosphate (PQ) as a promising therapeutic candidate for HHV-8-associated PEL and KS. Indeed, PQ strongly reduced cell viability through caspase-dependent apoptosis, specifically in HHV-8-infected PEL cells. Reactive oxygen species (ROS)- and endoplasmic reticulum (ER) stress-mediated apoptosis signaling pathways were found to be part of the in vitro cytotoxic effect of PQ. Moreover, PQ treatment had a clinically positive effect in a nonobese diabetic (NOD)/SCID xenograft PEL mouse model, showing a reduction in tumor growth and an improvement in survival. Finally, an exploratory proof-of-concept clinical trial in four patients harboring severe KS was conducted, with the main objectives to assess the efficacy, the safety, and the tolerability of PQ, and which demonstrated a positive efficacy on Kaposi’s sarcoma-related lesions and lymphedema.

Virucidal and biodegradable specialty cellulose nonwovens as personal protective equipment against COVID-19 pandemic

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Enable to instantly inactivate SARS-CoV-2 (>99.14%) and HCoV-229E (>98.83%).

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Excellent growth inhibition (>99.51%) towards both E. coli and S. aureus.

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Address the environmental concerns raised by non-biodegradable face masks.

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Development of safe, comfortable, and biodegradable textiles for PPE.

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A facile and scalable method to produce biocidal textiles for various applications.

Introduction

Face masks are regarded as effective Personal Protective Equipment (PPE) during the COVID-19 pandemic. However, the dominant polypropylene (PP)-based masks are devoid of antiviral/antibacterial activities and create enormous environmental burdens after disposal.

Objectives

Here we report a facile and potentially scalable method to fabricate biodegradable, breathable, and biocidal cellulose nonwovens (BCNWs) to address both environmental and hygienic problems of commercially available face masks.

Methods

TEMPO-oxidized cellulose nonwovens are rendered antiviral/antibacterial via covalent bonding with disinfecting polyhexamethylene guanidine or neomycin sulfate through carbodiimide coupling chemistry.

Results

The obtained results showed that the BCNWs have virucidal rate of >99.14%, bactericidal efficiency of >99.51%, no leaching-out effect, and excellent air permeability of >1111.5 mm s⁻¹. More importantly, the as-prepared BCNWs can inactivate SARS-CoV-2 instantly.

Conclusions

This strategy provides a new platform for the green fabrication of multifunctional cellulose nonwovens as scalable bio-protective layers with superior performance for various PPE in fighting COVID-19 or future pandemics. Additionally, replacing the non-biodegradable non-antimicrobial PP-based masks with the cellulose-based masks can reduce the plastic wastes and lower the greenhouse gas production from the incineration of disposed masks.

Kaposi's sarcoma-associated herpesvirus latency-associated nuclear antigen dysregulates expression of MCL-1 by targeting FBW7

Primary effusion lymphoma (PEL) is an aggressive B cell lymphoma that is etiologically linked to Kaposi’s sarcoma-associated herpesvirus (KSHV). Despite standard multi-chemotherapy treatment, PEL continues to cause high mortality. Thus, new strategies to control PEL are needed urgently. Here, we show that a phosphodegron motif within the KSHV protein, latency-associated nuclear antigen (LANA), specifically interacts with E3 ubiquitin ligase FBW7, thereby competitively inhibiting the binding of the anti-apoptotic protein MCL-1 to FBW7. Consequently, LANA-FBW7 interaction enhances the stability of MCL-1 by preventing its proteasome-mediated degradation, which inhibits caspase-3-mediated apoptosis in PEL cells. Importantly, MCL-1 inhibitors markedly suppress colony formation on soft agar and tumor growth of KSHV⁺PEL/BCBL-1 in a xenograft mouse model. These results strongly support the conclusion that high levels of MCL-1 expression enable the oncogenesis of PEL cells and thus, MCL-1 could be a potential drug target for KSHV-associated PEL. This work also unravels a mechanism by which an oncogenic virus perturbs a key component of the ubiquitination pathway to induce tumorigenesis.

Primary effusion lymphoma (PEL), a highly aggressive B cell lymphoma, is associated with Kaposi’s sarcoma-associated herpesvirus (KSHV). However, the underlying mechanisms that govern the aggressiveness of KSHV-associated PEL are poorly understood. Here, we demonstrate that KSHV LANA interacts with cellular ubiquitin E3 ligase FBW7, sequestering MCL-1 from FBW7, which reduces MCL-1 ubiquitination. As such, LANA potently stabilizes and increases MCL-1 protein, leading to inhibition of caspase-3-mediated apoptosis in PEL cells. Furthermore, MCL-1 inhibitors efficiently blocked PEL progression in mouse xenograft model. These results suggest that LANA acts as a proto-oncogene via deregulating tumor suppressor FBW7, which upregulates anti-apoptotic MCL-1 expression. This study suggests drugs that target MCL-1 may serve as an effective therapy against KSHV⁺ PEL.

Chlorin e6-loaded sonosensitive magnetic nanoliposomes conjugated with the magnetic field for enhancing anti-tumor effect of sonodynamic therapy

In sonodynamic therapy (SDT), when Chlorin e6 (Ce6) accumulates in tumor tissues, its anti-tumor effect can be achieved by ultrasound activation. To increase the local drug concentration of Ce6 in tumor cells, we had established a novel drug delivery system, Ce6-loaded sonosensitive magnetic nanoliposome (Ce6/SML), which realized the targeting delivery by the external magnetic field. It was worth mentioning that the targeting release of Ce6/SML and the activation on Ce6 could be achieved simultaneously by ultrasound of SDT. In our study, after Ce6 was loaded into the sonosensitive magnetic nanoliposome (SML), the values of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in vitro and in vivo were determined, indicating the activation on Ce6 of ultrasound. The delivery system also displayed the tumor-targeting ability and anti-tumor activity, which associated with the determined tumor growth and expression levels of angiogenin (ANG), vascular endothelial growth factor (VEGF) and tumor necrosis factor-alpha (TNF-α). In conclusion, the Ce6/SML-SDT-Targeted delivery system could effectively enhance the anti-tumor activity of SDT and had a great potential application for the treatment of malignant tumors located in deep tissues.

Latency-associated nuclear antigen inhibits lytic replication of Kaposi's sarcoma-associated herpesvirus by regulating let-7a/RBPJ signaling

Latency-associated nuclear antigen (LANA) is the key factor in the establishment and maintenance of latency of Kaposi's sarcoma-associated herpesvirus (KSHV). A cellular protein, recombination signal binding protein for immunoglobulin kappa J region (RBPJ), is essential for the lytic reactivation of KSHV. However, whether RBPJ expression is regulated by KSHV is not clear. Here, we show that LANA upregulates let-7a and its primary transcripts in parallel with its reduction of RBPJ expression. An increase in notch intracellular domain (NICD) and the downregulation of NF-κB and LIN28B contribute to the upregulation of let-7a by LANA. Let-7a represses RBPJ expression by directly binding the 3' untranslated region of RBPJ. Let-7a overexpression or RBPJ knockdown led to a dose- and time-dependent inhibition of lytic reactivation of KSHV. Collectively, these findings support a model wherein LANA inhibits the lytic replication of KSHV by regulating let-7a/RBPJ signaling.

Nuclear Innate Immune DNA Sensor IFI16 Is Degraded during Lytic Reactivation of Kaposi's Sarcoma-Associated Herpesvirus (KSHV): Role of IFI16 in Maintenance of KSHV Latency

IFI16 (interferon gamma-inducible protein 16) recognizes nuclear episomal herpesvirus (Kaposi's sarcoma-associated herpesvirus [KSHV], Epstein-Barr virus [EBV], and herpes simplex virus 1 [HSV-1]) genomes and induces the inflammasome and interferon beta responses. It also acts as a lytic replication restriction factor and inhibits viral DNA replication (human cytomegalovirus [HCMV] and human papillomavirus [HPV]) and transcription (HSV-1, HCMV, and HPV) through epigenetic modifications of the viral genomes. To date, the role of IFI16 in the biology of latent viruses is not known. Here, we demonstrate that knockdown of IFI16 in the latently KSHV-infected B-lymphoma BCBL-1 and BC-3 cell lines results in lytic reactivation and increases in levels of KSHV lytic transcripts, proteins, and viral genome replication. Similar results were also observed during KSHV lytic cycle induction in TREX-BCBL-1 cells with the doxycycline-inducible lytic cycle switch replication and transcription activator (RTA) gene. Overexpression of IFI16 reduced lytic gene induction by the chemical agent 12-O-tetradecoylphorbol-13-acetate (TPA). IFI16 protein levels were significantly reduced or absent in TPA- or doxycycline-induced cells expressing lytic KSHV proteins. IFI16 is polyubiquitinated and degraded via the proteasomal pathway. The degradation of IFI16 was absent in phosphonoacetic acid-treated cells, which blocks KSHV DNA replication and, consequently, late lytic gene expression. Chromatin immunoprecipitation assays of BCBL-1 and BC-3 cells demonstrated that IFI16 binds to KSHV gene promoters. Uninfected epithelial SLK and osteosarcoma U2OS cells transfected with KSHV luciferase promoter constructs confirmed that IFI16 functions as a transcriptional repressor. These results reveal that KSHV utilizes the innate immune nuclear DNA sensor IFI16 to maintain its latency and repression of lytic transcripts, and a late lytic KSHV gene product(s) targets IFI16 for degradation during lytic reactivation.

IMPORTANCE

Like all herpesviruses, latency is an integral part of the life cycle of Kaposi's sarcoma-associated herpesvirus (KSHV), an etiological agent for many human cancers. Herpesviruses utilize viral and host factors to successfully evade the host immune system to maintain latency. Reactivation is a complex event where the latent episomal viral genome springs back to active transcription of lytic cycle genes. Our studies reveal that KSHV has evolved to utilize the innate immune sensor IFI16 to keep lytic cycle transcription in dormancy. We demonstrate that IFI16 binds to the lytic gene promoter, acts as a transcriptional repressor, and thereby helps to maintain latency. We also discovered that during the late stage of lytic replication, KSHV selectively degrades IFI16, thus relieving transcriptional repression. This is the first report to demonstrate the role of IFI16 in latency maintenance of a herpesvirus, and further understanding will lead to the development of strategies to eliminate latent infection.

Three decades of research on angiogenin: a review and perspective

As a member of the vertebrate-specific secreted ribonucleases, angiogenin (ANG) was first isolated and identified solely by its ability to induce new blood vessel formation, and now, it has been recognized to play important roles in various physiological and pathological processes through regulating cell proliferation, survival, migration, invasion, and/or differentiation. ANG exhibits very weak ribonucleolytic activity that is critical for its biological functions, and exerts its functions through activating different signaling transduction pathways in different target cells. A series of recent studies have indicated that ANG contributes to cellular nucleic acid metabolism. Here, we comprehensively review the results of studies regarding the structure, mechanism, and function of ANG over the past three decades. Moreover, current problems and future research directions of ANG are discussed. The understanding of the function and mechanism of ANG in a wide context will help to better delineate its roles in diseases, especially in cancer and neurodegenerative diseases.

Triptolide decreases expression of latency-associated nuclear antigen 1 and reduces viral titers in Kaposi's sarcoma-associated and herpesvirus-related primary effusion lymphoma cells

Kaposi's sarcoma-associated herpesvirus (KSHV) can establish a life-long persistence in the host after primary infection and is associated with certain malignancies, which are resistant to conventional chemotherapeutic agents with a poor prognosis. Latency-associated nuclear antigen 1 (LANA1) encoded by KSHV is essential for segregation, replication and maintenance of viral genome. In addition, LANA1 upregulates the transcriptional activity of signal transducer and activator of transcription 3 (STAT3), which plays an important role in promoting survival of KSHV-associated primary effusion lymphoma (PEL) cells. Furthermore, LANA1 mediates transcriptional modulation of KSHV and host genome in host cells. In the present study, the antitumor effect of triptolide was assessed. CCK-8 assays were performed to demonstrate that the proliferations of PEL cells were efficiently inhibited by triptolide in a dose- and time-dependent manner. Flow cytometric results indicated that triptolide induced cell cycle arrest and apoptosis. Western blot results suggested that triptolide downregulated LANA1 expression and reduced half-life of LANA1 in the KSHV-infected malignant cells. Viral titer experiments indicated that triptolide treatment impaired the number of viral DNA copies and the production of virions in BCBL-1 cells. Triptolide also suppressed STAT3 activity and inhibited secretion of IL-6 in PEL cells. In a mouse xenograft model of primary effusion lymphoma by BCBL-1 cells, triptolide treatment significantly inhibited ascites formation and diffused organ infiltration. These results indicate that triptolide impairs the expression of LANA1 and shows antitumor activity against PEL in vitro and in vivo. Triptolide may be a potential agent for treatment of PEL.

How do viruses trick B cells into becoming lymphomas?

PURPOSE OF REVIEW

Since the discovery of Epstein-Barr virus in Burkitt's lymphoma 50  years ago, only one other virus, namely Kaposi's sarcoma-associated herpesvirus/human herpesvirus-8, has been confirmed to be a direct cause of B-cell lymphoma. Here we will review the evidence for Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus as causal lymphoma agents.

RECENT FINDINGS

A deeper understanding of specific mechanisms by which Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus cause B-cell lymphomas has been acquired over the past years, in particular with respect to viral protein interactions with host cell pathways, and microRNA functions. Specific therapies based on knowledge of viral functions are beginning to be evaluated, mostly in preclinical models.

SUMMARY

Understanding the causal associations of specific infectious agents with certain B-cell lymphomas has allowed more accurate diagnosis and classification. A deeper knowledge of the specific mechanisms of transformation is essential to begin assessing whether virus-targeted treatment modalities may be used in the future.

Neamine is preferential as an anti-prostate cancer reagent by inhibiting cell proliferation and angiogenesis, with lower toxicity than cis-platinum

Hormone therapy is the most commonly used treatment for prostate cancer, but for androgen-independent cancer, few effective treatment methods are available. Therefore, the requirement to develop novel and effective anti-prostate cancer drugs is extremely urgent. Angiogenin has been suggested as a molecular target for prostate cancer treatment; its overexpression contributes to androgen-dependent prostate cancer growth and castration-resistant growth of androgen-independent prostate cancer. The aim of the present study was to investigate whether neamine, a low toxicity angiogenin nuclear translocation inhibitor, has preferential anti-prostate cancer activity compared with cis-platinum (DDP) and the mechanisms involved. Immunofluorescence and MTT assays were used to observe the effect of neamine on the nuclear translocation of angiogenin and cell proliferation, and a PC-3 cell transplanted tumor model was used to investigate the in vivo activity of neamine and DDP. Immunohistochemistry was performed to observe the expression of angiogenin, cluster of differentiation (CD)31 and Ki-67. It was found that neamine blocked nuclear translocation of angiogenin effectively and inhibited angiogenin-induced human umbilical vein endothelial cell and PC-3 cell proliferation in a dose-dependent manner. Neamine exerted a comparative antitumor effect, but lower toxicity (weight loss), in the PC-3 xenograft models treated with DDP. Neamine consistently reduced the expression of angiogenin and CD31 significantly, but no difference was found in Ki-67 expression compared with DDP. These data suggested that neamine may be a promising agent for prostate cancer treatment.

Angiogenin secretion from hepatoma cells activates hepatic stellate cells to amplify a self-sustained cycle promoting liver cancer

Hepatocellular carcinoma (HCC) frequently develops in a pro-inflammatory and pro-fibrogenic environment with hepatic stellate cells (HSCs) remodeling the extracellular matrix composition. Molecules secreted by liver tumors contributing to HSC activation and peritumoral stromal transformation remain to be fully identified. Here we show that conditioned medium from HCC cell lines, Hep3B and HepG2, induced primary mouse HSCs transdifferentiation, characterized by profibrotic properties and collagen modification, with similar results seen in the human HSC cell line LX2. Moreover, tumor growth was enhanced by coinjection of HepG2/LX2 cells in a xenograft murine model, supporting a HCC-HSC crosstalk in liver tumor progression. Protein microarray secretome analyses revealed angiogenin as the most robust and selective protein released by HCC compared to LX2 secreted molecules. In fact, recombinant angiogenin induced in vitro HSC activation requiring its nuclear translocation and rRNA transcriptional stimulation. Moreover, angiogenin antagonism by blocking antibodies or angiogenin inhibitor neomycin decreased in vitro HSC activation by conditioned media or recombinant angiogenin. Finally, neomycin administration reduced tumor growth of HepG2-LX2 cells coinjected in mice. In conclusion, angiogenin secretion by HCCs favors tumor development by inducing HSC activation and ECM remodeling. These findings indicate that targeting angiogenin signaling may be of potential relevance in HCC management.