E2 Protein Research Articles

Herpes Simplex Virus, Human Papillomavirus, and Cervical Cancer: Overview, Relationship, and Treatment Implications.

There is a significant body of research examining the role of human papillomavirus (HPV) in the pathogenesis of cervical cancer, with a particular emphasis on the oncogenic proteins E5, E6, and E7. What is less well explored, however, is the relationship between cervical cancer and herpes simplex virus (HSV). To date, studies examining the role of HSV in cervical cancer pathogenesis have yielded mixed results. While several experiments have determined that HPV/HSV-2 coinfection results in a higher risk of developing cervical cancer, others have questioned the validity of this association. However, clarifying the potential role of HSV in the pathogenesis of cervical cancer may have significant implications for both the prevention and treatment of this disease. Should this relationship be clarified, treating and preventing HSV could open another avenue with which to prevent cervical cancer. The importance of this is highlighted by the fact that, despite the creation of an effective vaccine against HPV, cervical cancer still impacts 604,000 women and is responsible for 342,000 deaths annually. This review provides an overview of HSV and HPV infections and then delves into the possible links between HPV, HSV, and cervical cancer. It concludes with a summary of preventive measures against and recent treatment advances in cervical cancer.

Icariin, a phytoestrogen, exerts rapid estrogenic actions through crosstalk of estrogen receptors in osteoblasts.

Icariin, a flavonoid glycoside derived from Epimedium brevicornum Maxim, exerts bone protective effects via estrogen receptors (ERs). This study aimed to investigate the role of ER-α66, ER-α36, and GPER in bone metabolism in osteoblasts following treatment with icariin. Human osteoblastic MG-63 cells and osteoblast-specific ER-α66 knockout mice were employed. The ERs crosstalk in the estrogenic action of icariin was evaluated in ER-α66-negative human embryonic kidney HEK293 cells. Icariin, like E2, regulated ER-α36 and GPER protein expression in osteoblasts by downregulating them and upregulating ER-α66. ER-α36 and GPER suppressed the actions of icariin and E2 in bone metabolism. However, the in vivo administration of E2 (2 mg/kg/day) or icariin (300 mg/kg/day) restored bone conditions in KO osteoblasts. ER-α36 and GPER expression increased significantly and rapidly activated and translocated in KO osteoblasts after treatment with E2 or icariin. ER-α36 overexpression in KO osteoblasts further promoted the OPG/RANKL ratio induced by E2 or icariin treatment. This study showed icariin and E2 elicit rapid estrogenic responses in bone through recruiting ER-α66, ER-α36, and GPER. Notably, in osteoblasts lacking ER-α66, ER-α36, and GPER mediate the estrogenic effects of icariin and E2, while in intact osteoblasts, ER-α36 and GPER act as negative regulators of ER-α66.

Variant Analysis of FOXE1 Gene in Non-Syndromic Cleft Lip and Palate Patients of Peshawar, Pakistan

One of the most common structural birth defects is the cleft lip and palate, having an incidence rate of 1:700 live births worldwide. It can be isolated cleft lip, isolated cleft palate or a combination of both cleft lip and palate. The orofacial cleft can be caused by a variety of genetic and environmental factors or through an interaction between these factors. The gene Fork-head Box protein E1 (FOXE1) has been documented to be involved with cleft lip and palate. The present study aims to screen mutations in FOXE1 and to correlate phenotype and genotype of affected individuals. After obtaining ethical approval, peripheral blood samples were collected from 100 affected individuals, irrespective of age and gender. The genomic DNA was extracted, followed by quality control through spectrophotometer and gel electrophoresis. Polymerase chain reaction (PCR) was carried out to perform the targeted Sanger sequencing of FOXE1 gene. A point mutation (c.274C>T, rs3021526) in FOXE1 gene was detected in 15 samples. Based on phenotype, males and isolated cleft palate type was commonly involved,with bilateral occurrence, and moderate cases were frequently seen among the enrolled patients. In this study, a missense substitution was observed in gene FOXE1. This study provides a foundation for genetic counseling for families at risk and offer valuable insights for prevention and management plans.

Mus musculus papillomavirus 1 E8^E2 represses expression of late protein E4 in basal-like keratinocytes via NCoR/SMRT-HDAC3 co-repressor complexes to enable wart formation in vivo.

High-risk human papillomaviruses (PV) account for approximately 600,000 new cancers per year. The early protein E8^E2 is a conserved repressor of PV replication, whereas E4 is a late protein that arrests cells in G2 and collapses keratin filaments to facilitate virion release. While inactivation of the Mus musculus PV1 (MmuPV1) E8 start codon (E8-) increases viral gene expression, surprisingly, it prevents wart formation in FoxN1nu/nu mice. To understand this surprising phenotype, the impact of additional E8^E2 mutations was characterized in tissue culture and mice. MmuPV1 and HPV E8^E2 similarly interact with cellular NCoR/SMRT-HDAC3 co-repressor complexes. Disruption of the splice donor sequence used to generate the E8^E2 transcript or E8^E2 mutants (mt) with impaired binding to NCoR/SMRT-HDAC3 activates MmuPV1 transcription in murine keratinocytes. These MmuPV1 E8^E2 mt genomes also fail to induce warts in mice. The phenotype of E8^E2 mt genomes in undifferentiated cells resembles productive PV replication in differentiated keratinocytes. Consistent with this, E8^E2 mt genomes induced aberrant E4 expression in undifferentiated keratinocytes. In line with observations for HPV, MmuPV1 E4-positive cells displayed a shift to the G2 phase of the cell cycle. In summary, we propose that in order to enable both expansion of infected cells and wart formation in vivo, MmuPV1 E8^E2 inhibits E4 protein expression in the basal keratinocytes that would otherwise undergo E4-mediated cell cycle arrest. IMPORTANCE Human papillomaviruses (PVs) initiate productive replication, which is characterized by genome amplification and expression of E4 protein strictly within suprabasal, differentiated keratinocytes. Mus musculus PV1 mutants that disrupt splicing of the E8^E2 transcript or abolish the interaction of E8^E2 with cellular NCoR/SMRT-HDAC3 co-repressor complexes display increased gene expression in tissue culture but are unable to form warts in vivo. This confirms that the repressor activity of E8^E2 is required for tumor formation and genetically defines a conserved E8 interaction domain. E8^E2 prevents expression of E4 protein in basal-like, undifferentiated keratinocytes and thereby their arrest in G2 phase. Since binding of E8^E2 to NCoR/SMRT-HDAC3 co-repressor is required to enable expansion of infected cells in the basal layer and wart formation in vivo, this interaction represents a novel, conserved, and potentially druggable target.

HPV E6 inhibits E6AP to regulate epithelial homeostasis by modulating keratinocyte differentiation commitment and YAP1 activation.

Human papillomaviruses (HPV) cause persistent infections by modulating epithelial homeostasis in cells of the infected basal layer. Using FUCCI and cell-cell competition assays, we have identifed regulatory roles for E6AP and NHERF1, which are the primary HPV11 E6 cellular targets, as well as being targets of the high-risk E6 proteins, in processes governing epithelial homeostasis (i.e. cell density, cell cycle entry, commitment to differentiation and basal layer delamination). Depletion of E6AP, or expression of HPV11 or 16E6 increased keratinocyte cell density and cell cycle activity, and delayed the onset of differentiation; phenotypes which were conspicuously present in HPV11 and 16 infected patient tissue. In line with proposed E6 functions, in HPV11 condyloma tissue, E6AP and NHERF1 were significantly reduced when compared to uninfected epithelium. In experimental systems, loss of HPV11 E6/E6AP binding abolished 11E6's homeostasis regulatory functions, while loss of E6/NHERF1 binding reduced the cell density threshold at which differentiation was triggered. By contrast, a NHERF1-binding mutant of 16E6 was not compromised in its homeostasis functions, while E6AP appeared essential. RNA sequencing revealed similar transcriptional profiles in both 11 and 16E6-expressing cells and E6AP-/- cells, with YAP target genes induced, and keratinocyte differentiation genes being downregulated. HPV11 E6-mediated Yap activation was observed in 2D and 3D (organotypic raft) cell culture systems and HPV-infected lesions, with both NHERF1, which is a regulator of the Hippo and Wnt pathways, and E6AP, playing an important role. As the conserved binding partner of Alpha group HPV E6 proteins, the precise role of E6AP in modulating keratinocyte phenotype and associated signalling pathways has not previously been defined. Our study suggests a model in which the preserved functions of the low and high-risk Alpha E6 proteins modulate epithelial homeostasis via E6AP activity, and lead to alteration of multiple downstream pathways, including those involving NHERF1 and YAP.

Evidence for direct interaction between the oncogenic proteins E6 and E7 of high-risk human papillomavirus (HPV)

Human papillomaviruses (HPVs) are DNA tumor viruses that infect mucosal and cutaneous epithelial cells of more than 20 vertebrates. High-risk HPV causes about 5% of human cancers worldwide, and the viral proteins E6 and E7 promote carcinogenesis by interacting with tumor suppressors and interfering with many cellular pathways. As a consequence, they immortalize cells more efficiently in concert than individually. So far, the networks of E6 and E7 with their respective cellular targets have been studied extensively but independently. However, we hypothesized that E6 and E7 might also interact directly with each other in a novel interaction affecting HPV-related carcinogenesis. Here, we report a direct interaction between E6 and E7 proteins from carcinogenic HPV types 16 and 31. We demonstrated this interaction via cellular assays using two orthogonal methods: coimmunoprecipitation and flow cytometry-based FRET assays. Analytical ultracentrifugation of the recombinant proteins revealed that the stoichiometry of the E6/E7 complex involves two E7 molecules and two E6 molecules. In addition, fluorescence polarization showed that (I) E6 binds to E7 with a similar affinity for HPV16 and HPV31 (in the same micromolar range) and (II) that the binding interface involves the unstructured N-terminal region of E7. The direct interaction of these highly conserved papillomaviral oncoproteins may provide a new perspective for studying HPV-associated carcinogenesis and the overall viral life cycle.

P-631 Alleviating effects of EGCG on ovarian hyperstimulation syndrome and the potential modulating mechanism through the VEGF pathway

Abstract Study question What are the underlying mechanisms of EGCG to alleviate Ovary hyperstimulation syndrome (OHSS)? Summary answer EGCG inhibited VEGF via TGF-β1 classical-SMAD pathway and 67LR-mediated CREB pathway and could reduce the ovarian inflammatory effect and attenuated OHSS progress in rat model. What is known already Ovarian hyperstimulation syndrome (OHSS) is one of the most severe complications of COH during IVF treatment. The pathophysiology of OHSS is characterized by increased capillary permeability, VEGF is an important mediator in OHSS, and serum VEGF levels have been shown to correlate with OHSS severity. (-)-epigallocatechin-3-gallate (EGCG) is the most abundant and biologically active polyphenolic catechin in green tea and has been reported to have multiple effects in humans. Many research indicated that in many pathological processes, EGCG could inhibit VEGF and its receptor expression and have an angiogenesis effect. Herein, EGCG might have a therapeutic effect on OHSS. Study design, size, duration We investigated the role of EGCG in OHSS in vitro and in vivo. The primary human granulosa-lutein(hGL) cells and human granulosa-like tumor (KGN) cell line were cultured and treated with different concentrations of EGCG for 24 hours. Animal OHSS model was established in SD rats by injection of pregnant mare serum gonadotropin (PMSG), and randomly assigned to receive vehicle only or EGCG for 3 days. All experiments were performed 3-8 times for comparisons. Participants/materials, setting, methods The effect of EGCG on KGN and hGL cells was determined by MTT assay. The body weight of rats was measured every day, and the ovary size was measured after removal, the permeability was determined by Evans-blue. The serum estrogen and VEGF level in rats were detected by ELISA. RNA and protein expressions of VEGF, VEGFR-2, TGF-β, and TβR II were detected by qPCR and Western-blotting and immunostaining in vitro and in vivo experiments. Main results and the role of chance Our study demonstrated that administration of EGCG attenuated the development of OHSS in rats, as shown by histological examination and ovarian weight and morphology. The ovary weight was significantly decreased in the EGCG treatment group compared with the OHSS group (147.9 vs 206.5 mg). Additionally, compared to OHSS rats, EGCG treated rats exhibit downregulated ovarian VEGF expression determined by IHC and RT-qPCR. VEGF and E2 protein levels significantly decrease in the serum of the EGCG treatment group. EGCG exerted inhibitory effects on cell growth only in high dose (50uM) and longtime (48h) treatment in KGN and hGL cells. In KGN cells and hGL cells, EGCG significantly reduces the expression of VEGF and TGF-β at the RNA and protein levels. Furthermore, EGCG inhibits TGF-β1-induced VEGF production and secretion in KGN cells by suppressing TGF-β expression and its traditional Smad signaling pathway. EGCG also downregulates VEGF expression through the 67-kDa laminin receptor-mediated PKA-CREB pathway. Limitations, reasons for caution EGCG has been reported to employ a wide range of biological effects. Therefore, its suppressive effects on VEGF and TGF-β signaling pathway might be part of the pharmacological mechanisms to alleviate Ovary hyperstimulation syndrome. Further studies are also needed to explore the therapeutic mechanisms of melatonin from other perspectives. Wider implications of the findings Our findings add mechanistic insight in support of using EGCG as an adjuvant therapy in the management of OHSS. EGCG shows the potential to act as a novel alternative therapeutic drug to treat OHSS. Daily intake of green tea might be beneficial for women under COH to prevent OHSS. Trial registration number Not applicable

Retraction Note: Human papillomavirus type 77 E6 protein selectively inhibits p53-dependent transcription of proapoptotic genes following UV-B irradiation.

Retraction Note: Human papillomavirus type 77 E6 protein selectively inhibits p53-dependent transcription of proapoptotic genes following UV-B irradiation.

High-risk human papillomavirus prevalence among patients with cervical cancer at Moewardi General Hospital in Surakarta, Indonesia

Link of Video Abstract: https://www.youtube.com/watch?v=Ryf_-hvseVc Introduction: In Indonesia, cervical cancer is the second most prevalent type of cancer among the general population. Cervical cancer has the second-highest mortality rate of all cancers. Infection with the Human Papilloma Virus (HPV) is one of the causes that starts the growing phase of cervical cancer. The purpose of this study, therefore, is to determine the prevalence of HPV infection in patients with cervical cancer who were examined at Dr. Moewardi Hospital and lived in the ex-Surakarta Residency. Methods: Cervical tissue biopsy at the Anatomical Pathology Installation of Dr. Moewardi General Hospital Surakarta which had been diagnosed as cervical cancer was examined by the detection of E6 protein from HPV 16 and HPV 18 using immunohistochemical staining techniques. The data obtained would be analyzed based on the characteristics of the patient's age and the degree of histopathological malignancy with a p-value < 0.05 deemed significant. Results: Overall, the prevalence of high-risk HPV infection was 77.8% (35/45), with women aged between 41-55 years having the highest prevalence of HPV infection (45.7, 16/35), followed by women aged 56-70 (42.9%), women over 70 (8.6%) and women under 40 (2.9%). The results of statistical tests showed that no significant relationship was found between HPV infection and age (p = 0.428). High-risk HPV infection was most prevalent in the poorly differentiated group (54.3%), followed by the well-differentiated group (34.3%) and the moderately differentiated group (11.4%). The results of statistical tests revealed a significant association between HPV infection and tumor grade (p = 0.027). Conclusion: To lower patient morbidity and mortality, it is crucial to receive a prophylactic HPV vaccine due to the incidence of HPV 16 and 18 infections in patients with cervical cancer at the Regional Hospital Dr. Moewardi Surakarta, with a prevalence of 77.8%.

Identification of two novel T cell epitopes on the E2 protein of classical swine fever virus C-strain

C-strain, also known as the HCLV strain, is a well-known live attenuated vaccine against classical swine fever (CSF), a devastating disease caused by classical swine fever virus (CSFV). Vaccination with C-strain induces a rapid onset of protection, which is associated with virus-specific gamma interferon (IFN-γ)-secreting CD8+ T cell responses. The E2 protein of CSFV is a major protective antigen. However, the T cell epitopes on the E2 protein remain largely unknown. In this study, eight overlapping nonapeptides of the E2 protein were predicted and synthesized to screen for potential T cell epitopes on the CSFV C-strain E2 protein. Molecular docking was performed on the candidate epitopes with the swine leukocyte antigen-1*0401. The analysis obtained two highly conserved T cell epitopes, 90STEEMGDDF98 and 331ATDRHSDYF339, which were further identified by enzyme-linked immunospot assay. Interestingly, the mutants deleting or substituting the epitopes are nonviable. Further analysis demonstrated that 90STEEMGDDF98 is crucial for the E2 homodimerization, while CSFV infection is significantly inhibited by the 331ATDRHSDYF339 peptide treatment. The two novel T cell epitopes can be used to design new vaccines that are able to provide rapid-onset protection.

Shaoyao Gancao decoction alleviates the central hyperalgesia of recurrent NTG-induced migraine in rats by regulating the NGF/TRPV1/COX-2 signal pathway

Ethnopharmacological relevanceShaoyao Gancao Decoction (SGD) is well known as an effective prescription for analgesia composed of two herbs, and is noted as traditional Chinese medicine morphine. It is widely used in various conditions causing pain, including migraine. However, there is currently no research exploring the mechanism of action in the treatment of migraines. Aim of the studyThe current research was devised to determine the underlying regulatory mechanism of SGD, by verifying its role in the NGF/TRPV1/COX-2 signal pathway. Materials and methodsThe active components in SGD were identified by UHPLC-MS. A migraine model was prepared by subcutaneous (s.c.) injection of nitroglycerin (NTG) into the neck to detect migraine-like behavior, orbital hyperalgesia threshold changes, and the therapeutic effect of SGD. The mechanism of SGD in remedying migraine was studied through transcriptome sequencing (RNA-seq), which was further validated utilizing Elisa, Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting (WB) experiments. ResultsIn the SGD chemical composition analysis, 45 components were identified including gallic acid, paeoniflorin and albiforin. In the behavioral experiments, SGD treatment significantly decreased the score of migraine-like head scratching in the NTG-induced migraine model (Mod) rats, while the hyperalgesia threshold increased outstandingly on days 10, 12, and 14 (P < 0.01, P < 0.001 or P < 0.0001). In migraine biomarkers experiment, compared with the Mod group, the 5-hydroxytryptamine (5-HT) contents were outstandingly enhanced by SGD treatment, while nitric oxide (NO) contents were markedly declined (P < 0.01). In the RNA-seq test, the down-regulated genes of SGD inhibiting hyperalgesia migraine included the neurotrophic factor (NGF) and transient receptor potential vanillic acid subfamily protein 1 receptor (TRPV1). The down-regulation pathway is the inflammatory mediator regulation of TRP channels. In gene set enrichment analysis (GSEA), SGD decreased the over-expression of protooncogene tyrosine-protein kinase Src (SRC) and TRPV1 in this pathway, and the two genes clustered at its lower end, with similar functions. PPI network results show that NGF interacts with TRPV1. Further verification shows that when compared with Mod group, the plasma cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2) protein expression levels and the dura mater calcitonin gene-related peptide (CGRP), extracellular signal-regulated kinase (ERK), p-ERK, SRC and NGF protein expression levels in the SGD group were remarkably decreased (P < 0.01, P < 0.001 or P < 0.0001), and the expression level of TRPV1 protein showed a downward trend (P = 0.06). The expression levels of COX-2, NO, CGRP, TRPV1, SRC and NGF mRNA in the dura mater was overtly down-regulated (P < 0.05, P < 0.01 or P < 0.001). ConclusionsSGD has a significant inhibitory effect on the NGF/TRPV1/COX-2 signaling pathway that mediates central hyperalgesia migraine, thus suggesting the molecular mechanism of SGD in improving the symptoms of migraine may be related to the central hyperalgesia neurotransmitter that regulates the pathogenesis of migraine.

Phosphorylation of E2 Serine Residue 402 Is Required for the Transcription and Replication of the HPV5 Genome.

Cutaneous human papillomavirus type 5 (HPV5) belongs to the supposedly oncogenic β-HPVs associated with specific types of skin and oral cavity cancers. Three viral proteins, namely, helicase E1 and transcription factors E2 and E8^E2, are master regulators of the viral life cycle. HPV5 E2 is a transcriptional activator that also participates in the E1-dependent replication and nuclear retention of the viral genome, whereas E8^E2 counterbalances the activity of E2 and inhibits HPV transcription and replication. In the present study, we demonstrate that the HPV5 E2 protein is extensively phosphorylated by cellular protein kinases, and serine residue 402 (S402) is the highest scoring phosphoacceptor site. This residue is located within a motif conserved among many β-HPVs and in the oncogenic HPV31 α-type. Using the nonphosphorylatable and phosphomimetic mutants, we demonstrate that phosphorylation of the E2 S402 residue is required for the transcription and replication of the HPV5 genome in U2OS cells and human primary keratinocytes. Mechanistically, the E2-S402-phopshodeficient protein is unable to trigger viral gene transcription and has an impaired ability to support E1-dependent replication, but the respective E8^E2-S213 mutant displays no phenotype. However, phosphorylation of the E2 S402 residue has no impact on the E2 stability, subcellular localization, self-assembly, DNA-binding capacity, and affinity to the E1 and BRD4 proteins. Further studies are needed to identify the protein kinase(s) responsible for this phosphorylation. IMPORTANCE Human papillomavirus type 5 (HPV5) may play a role in the development of specific types of cutaneous and head and neck cancers. The persistence of the HPV genome in host cells depends on the activity of its proteins, namely, a helicase E1 and transcription/replication factor E2. The latter also facilitates the attachment of episomal viral genomes to host cell chromosomes. In the present study, we show that the HPV5 E2 protein is extensively phosphorylated by host cell protein kinases, and we identify serine residue 402 as the highest scoring phosphoacceptor site of E2. We demonstrate that the replication of the HPV5 genome may be blocked by a single point mutation that prevents phosphorylation of this serine residue and switches off the transcriptional activity of the E2 protein. The present study contributes to a better understanding of β-HPV5 replication and its regulation by host cell protein kinases.

Current Status of Human Papillomavirus–Targeted Therapies Development in Head and Neck Cancer

PURPOSE While the incidence of smoking-related head and neck squamous cell carcinoma (HNSCC) has been declining, that of human papillomavirus (HPV)–mediated HNSCC has rapidly increased in the past decades worldwide. Despite rapid advances in therapeutics for solid tumors with novel immunotherapy and targeted therapeutic agents, no breakthroughs have yet been made in the treatment of advanced HPV+ HNSCCs. This review aims to summarize the concepts and designs, early trial results, and future directions of various HPV-targeted experimental therapeutics for HPV+ HNSCC. MATERIALS AND METHODS Guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, a systemic literature search of PubMed was conducted for HPV-targeted therapeutics using the following search terms: HPV, head and neck squamous cell carcinoma, and therapy. For clinical trial data, publications, major oncology conference abstracts, and the National Institutes of Health Clinical Trials Registry (ClinicalTrials.gov) information were reviewed. This review focused on the ones that are in the clinical stage and currently in active ongoing evaluation. The therapeutics not actively evaluated in HNSCC, in the preclinical stage, or terminated for further development were excluded. RESULTS Diverse approaches are being actively explored to target HPV+ HNSCC, including therapeutic vaccines of various modalities, HPV-specific immune cell–activating agents, and adaptive cellular therapeutics. All these novel agents use immune-based mechanisms and target constitutively expressed oncogenic HPV E6 and/or E7 viral proteins. Most therapeutics demonstrated excellent safety but single-agent activities are only modest. Many are being tested in combination with immune checkpoint inhibitors. CONCLUSION Our review summarized various novel HPV-targeted therapeutics that are in the clinical phase for HPV+ HNSCC. Early-phase trial data suggest the feasibility and promising efficacy. Further strategies, including selecting the optimal combination and understanding and overcoming resistant mechanisms, are warranted for successful development.

A phase 1 dose-escalation and expansion study of CUE-101, a novel HPV16 E7-pHLA-IL2-Fc fusion protein, given as monotherapy and in combination with pembrolizumab in patients with recurrent/metastatic HPV16+ head and neck cancer.

6013 Background: Immuno-STATs are modular T cell engagers engineered to selectively activate tumor-antigen specific CD8+ T cells via targeted delivery of cytokines. CUE-101, the first Immuno-STAT in clinical trials, is composed of a human leukocyte antigen (HLA) complex, HLA-A*0201, a peptide epitope derived from the HPV16 E7 protein, and 4 molecules of attenuated human interleukin-2 (IL-2) designed to bind, expand, and activate HPV16-specific CD8+ T cells for the treatment of HPV16+ cancers. Methods: CUE-101-01 is an ongoing first-in-human study in HLA-A*0201 patients with HPV16+ recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC). Escalating doses of CUE-101 monotherapy (0.06 mg/kg to 8 mg/kg) and in combination with pembrolizumab (1 mg/kg to 4 mg/kg + 200 mg pembrolizumab) were evaluated, followed by expanded enrollment at the recommended phase 2 dose (RP2D). Patients with R/M HNSCC refractory to ≥ 1 platinum-based or checkpoint inhibitor therapy received CUE-101 monotherapy. Patients with previously untreated PD-L1+ R/M HNSCC received CUE-101 + pembrolizumab as first-line treatment. Therapy was administered every 3 weeks until disease progression or intolerable toxicity. Safety, pharmacokinetics (PK), pharmacodynamics (PD), and antitumor activity were assessed. Results: As of January 12, 2023, 67 patients were enrolled. A MTD was not established in monotherapy or combination-treated patients; 4 mg/kg of CUE-101, alone or in combination with pembrolizumab, was chosen as the RP2D dose in both cohorts. Monotherapy RP2D enrollment is complete and combination RP2D enrollment is ongoing. Frequent adverse events include fatigue (45%), anemia (34%), chills (27%), infusion related reactions (25%), constipation (22%), lymphopenia (22%) and nausea (22%). CUE-101 PK data demonstrate dose-dependent increases in drug exposure sustained with repeat dosing. PD data demonstrate selective expansion of HPV-16 E711-20-specific CD8+ T cells, sustained increase in NK cells and transient increase in Treg cells. Among 19 evaluable monotherapy RP2D patients, 1 PR and 6 durable SD (SD ≥ 12 weeks) were observed, with mOS of 24.4 months (9.1, NA). Among 12 evaluable RP2D combination patients to date, 5 PRs, and 2 durable SDs have been observed, with 71% (5/7) of patients expressing PD-L1 CPS ≤ 20. Conclusions: CUE-101 facilitates the targeted delivery of high concentrations of IL-2 to relevant tumor-specific CD8+ T cells. We demonstrate safety and tolerability with encouraging PD signals and antitumor activity with monotherapy and in combination with pembrolizumab in HPV+ R/M HNSCC patients. Enrollment continues in the CUE-101 and pembrolizumab combination cohort. Clinical trial information: Clinical trial information: NCT03978689 .

Ethyl palmitate, an anti-chikungunya virus principle from Sauropus androgynus, a medicinal plant used to alleviate fever in ethnomedicine.

Sauropus androgynus is a medicinal shrub used for the treatment of fever in ethnomedical traditions in various Southeast Asian countries. This study was aimed to identify antiviral principles from S. androgynus against Chikungunya virus (CHIKV), a major mosquito-borne pathogen that re-emerged in the last decade, and to unravel their mechanism of action. Hydroalcoholic extract of S. androgynus leaves was screened for anti-CHIKV activity using cytopathic effect (CPE) reduction assay. The extract was subjected to activity guided isolation and the resultant pure molecule was characterized by GC-MS, Co-GC and Co-HPTLC. The isolated molecule was further evaluated for its effect by plaque reduction assay, western blot and immunofluorescence assays. In silico docking with CHIKV envelope proteins and molecular dynamics simulation (MD) analyses were used to elucidate its possible mechanism of action. S. androgynus hydroalcoholic extract showed promising anti-CHIKV activity and its active component, obtained by activity guided isolation, was identified as ethyl palmitate (EP), a fatty acid ester. At 1 μg/mL, EP led to 100% inhibition of CPE and a significant 3-log10 reduction in CHIKV replication in Vero cells at 48 h post-infection. EP was highly potent with an EC50 of 0.0019 μg/mL (0.0068 μM) and a very high selectivity index. EP treatment significantly reduced viral protein expression, and time of addition studies revealed that it acts at the stage of viral entry. A strong binding to the viral envelope protein E1 homotrimer during entry, thus preventing viral fusion, was identified as a possible mechanism by which EP imparts its antiviral effect. S. androgynus contains EP as a potent antiviral principle against CHIKV. This justifies the use of the plant against febrile infections, possibly caused by viruses, in various ethnomedical systems. Our results also prompt more studies on fatty acids and their derivatives against viral diseases.

Insights from the molecular docking analysis of gambogic acid with the Chikungunya spike glycoprotein E2.

Chikungunya fever is a mosquito-borne disease caused by the chikungunya virus (CHIKV) and has drawn substantial attention in recent years. So far, no effective treatment is available in the form of drugs or vaccines. In this study, we aimed to screen some drugs against the pathogenic Chikungunya virus through a molecular docking approach. As a fact, the spike E2 protein plays an important role in viral attachment to the human host cell, binding to a cell receptor MXRA8. The molecules screened for in-silico interaction against MXRA8 were selected with top hit based on binding affinity. The existing intermolecular bonds were investigated further in the active site of the protein that interacts with the top-hit ligands. Gambogic acid (guttic acid) was depicted as the furthermost potential inhibitor when compared to the others it had the lowest binding affinity (-10.9 kcal/mol). Gambogic acid, as a potential antiviral agent against the spike E2 protein, could be a promising candidate.

Experimental Support for Human Papillomavirus Genome Amplification Early after Infectious Delivery.

Even though replication and transcription of human papillomavirus type 16 (HPV16) has been intensively studied, little is known about immediate-early events of the viral life cycle due to the lack of an efficient infection model allowing genetic dissection of viral factors. We employed the recently developed infection model (Bienkowska-Haba M, Luszczek W, Myers JE, Keiffer TR, et al. 2018. PLoS Pathog 14:e1006846) to investigate genome amplification and transcription immediately after infectious delivery of viral genome to nuclei of primary keratinocytes. Using 5-ethynyl-2'-deoxyuridine (EdU) pulse-labeling and highly sensitive fluorescence in situ hybridization, we observed that the HPV16 genome is replicated and amplified in an E1- and E2-dependent manner. Knockout of E1 resulted in failure of the viral genome to replicate and amplify. In contrast, knockout of the E8^E2 repressor led to increased viral genome copy number, confirming previous reports. Genome copy control by E8^E2 was confirmed for differentiation-induced genome amplification. Lack of functional E1 had no effect on transcription from the early promoter, suggesting that viral genome replication is not required for p97 promoter activity. However, infection with an HPV16 mutant virus defective for E2 transcriptional function revealed a requirement of E2 for efficient transcription from the early promoter. In the absence of the E8^E2 protein, early transcript levels are unaltered and even decreased when normalized to genome copy number. Surprisingly, a lack of functional E8^E2 repressor did not affect E8^E2 transcript levels when normalized to genome copy number. These data suggest that the main function of E8^E2 in the viral life cycle is to control genome copy number. IMPORTANCE It is being assumed that human papillomavirus (HPV) utilizes three different modes of replication during its life cycle: initial amplification during the establishment phase, genome maintenance, and differentiation-induced amplification. However, HPV16 initial amplification was never formally proven due to a lack of an infection model. Using our recently established infection model (Bienkowska-Haba M, Luszczek W, Myers JE, Keiffer TR, et al. 2018. PLoS Pathog 14:e1006846), we demonstrate herein that viral genome is indeed amplified in an E1- and E2-dependent manner. Furthermore, we find that the main function of the viral repressor E8^E2 is to control viral genome copy number. We did not find evidence that it regulates its own promoter in a negative feedback loop. Our data also suggest that the E2 transactivator function is required for stimulation of early promoter activity, which has been debated in the literature. Overall, this report confirms the usefulness of the infection model for studying early events of the HPV life cycle using mutational approaches.

The Diagnostic Potential of RNA Aptamers against the NS1 Protein of Dengue Virus Serotype 2.

Dengue infection, caused by the dengue virus, is a global threat which requires immediate attention and appropriate disease management. The current diagnosis of dengue infection is largely based on viral isolation, RT-PCR and serology-based detection, which are time-consuming and expensive, and require trained personnel. For early diagnosis of dengue, the direct detection of a dengue antigenic target is efficacious, and one such target is NS1. NS1-based detection is primarily antibody-centric and is beset by drawbacks pertaining to antibodies such as the high cost of synthesis and large batch-to-batch variation. Aptamers are potential surrogates of antibodies and are much cheaper, without exhibiting batch-to-batch variation. Given these advantages, we sought to isolate RNA aptamers against the NS1 protein of dengue virus serotype 2. A total of 11 cycles of SELEX were carried out, resulting in two potent aptamers, DENV-3 and DENV-6, with dissociation constant values estimated at 37.57 ± 10.34 nM and 41.40 ± 9.29 nM, respectively. These aptamers can be further miniaturized to TDENV-3 and TDENV-6a with an increased LOD upon their usage in direct ELASA. Moreover, these truncated aptamers are highly specific against the dengue NS1 while showing no cross-reactivity against the NS1 of the Zika virus, the E2 protein of the Chikungunya virus or the LipL32 protein of Leptospira, with target selectivity retained even in human serum. The usage of TDENV-3 as the capturing probe and TDENV-6a as the detection probe underpinned the development of an aptamer-based sandwich ELASA for the detection of dengue NS1. The sensitivity of the sandwich ELASA was further improved with the stabilization of the truncated aptamers and the repeated incubation strategy, which enabled a LOD of 2 nM when used with the target NS1 spiked in human serum diluted at 1:2000.

Elucidating cellular interactome of chikungunya virus identifies host dependency factors

Chikungunya virus (CHIKV) is a re-emerging mosquito-transmitted RNA virus causing joint and muscle pain. To better understand how CHIKV rewires the host cell and usurps host cell functions, we generated a systematic CHIKV-human protein-protein interaction map and revealed several novel connections that will inform further mechanistic studies. One of these novel interactions, between the viral protein E1 and STIP1 homology and U-box containing protein 1 (STUB1), was found to mediate ubiquitination of E1 and degrade E1 through the proteasome. Capsid associated with G3BP1, G3BP2 and AAA+ ​ATPase valosin-containing protein (VCP). Furthermore, VCP inhibitors blocked CHIKV infection, suggesting VCP could serve as a therapeutic target. Further work is required to fully understand the functional consequences of these interactions. Given that CHIKV proteins are conserved across alphaviruses, many virus-host protein-protein interactions identified in this study might also exist in other alphaviruses. Construction of interactome of CHIKV provides the basis for further studying the function of alphavirus biology.

Current Hepatitis C Vaccine Candidates Based on the Induction of Neutralizing Antibodies.

The introduction of direct-acting antivirals (DAAs) has revolutionized hepatitis C treatment. Short courses of treatment with these drugs are highly beneficial to patients, eliminating hepatitis C virus (HCV) without adverse effects. However, this outstanding success is tempered by the continuing difficulty of eradicating the virus worldwide. Thus, access to an effective vaccine against HCV is strongly needed to reduce the burden of the disease and contribute to the elimination of viral hepatitis. The recent failure of a T-cell vaccine based on the use of viral vectors expressing the HCV non-structural protein sequences to prevent chronic hepatitis C in drug users has pointed out that the induction of neutralizing antibodies (NAbs) will be essential in future vaccine candidates. To induce NAbs, vaccines must contain the main target of this type of antibody, the HCV envelope glycoproteins (E1 and E2). In this review, we summarize the structural regions in E1 and E2 proteins that are targeted by NAbs and how these proteins are presented in the vaccine candidates currently under development.