FOXO1 enhances CAR T cell stemness, metabolic fitness and efficacy.

Chimeric antigen receptor (CAR) T cell therapy has transformed the treatment of haematological malignancies such as acute lymphoblastic leukaemia, B cell lymphoma and multiple myeloma1-4, but the efficacy of CAR T cell therapy in solid tumours has been limited5. This is owing to a number of factors, including the immunosuppressive tumour microenvironment that gives rise to poorly persisting and metabolically dysfunctional T cells. Analysis of anti-CD19 CAR T cells used clinically has shown that positive treatment outcomes are associated with a more 'stem-like' phenotype and increased mitochondrial mass6-8. We therefore sought to identify transcription factors that could enhance CAR T cell fitness and efficacy against solid tumours. Here we show that overexpression of FOXO1 promotes a stem-like phenotype in CAR T cells derived from either healthy human donors or patients, which correlates with improved mitochondrial fitness, persistence and therapeutic efficacy in vivo. This work thus reveals an engineering approach to genetically enforce a favourable metabolic phenotype that has high translational potential to improve the efficacy of CAR T cells against solid tumours.

Stabilization of Organic Cations in Lead Halide Perovskite Solar Cells Using Phosphine Oxides Derivatives.

Preventing ion migration in perovskite photovoltaics is key to achieving stable and efficient devices. The activation energy for ion migration is affected by the chemical environment surrounding the ions. Thus, the migration of organic cations in lead halide perovskites can be mitigated by engineering their local interactions, for example through hydrogen bonding. Ion migration also leads to ionic losses via interfacial reactions. Undesirable reactivities of the organic cations can be eliminated by introducing protecting groups. In this work, we report bis(2-oxo-3-oxazolidinyl) phosphinic chloride (BOP-Cl) as a perovskite ink additive with the following benefits: (1) The phosphoryl and two oxo groups form six-membered intermolecular hydrogen-bonded rings with the formamidinium cation (FA), mitigating ion migrations. (2) The hydrogen bonding reduces the electrophilicity of the ammonium protons by donating electron density, therefore reducing its reactivity with the surface oxygen on the metal oxide. Furthermore, the molecule can react to form a protecting group on the nucleophilic oxygen at the tin oxide transport layer surface through the elimination of chlorine. As a result, we achieve perovskite solar cells with an efficiency of 25.0% and improved MPP stability T93 = 1200 h at 40-45 °C compared to a control device (T86 = 550 h). In addition, we show a negative correlation between the strength of hydrogen bonding of different phosphine oxide derivatives to the organic cations and the degree of metastable behavior (e.g., initial burn-in) of the device.

Linearization of wavelength sweeping lasers for the construction of 4-D FMCW LiDAR images of slow-moving objects using baseband beat note signals.

A FMCW LiDAR system of both the distributed feedback laser and external cavity laser is established in baseband beat notes, rather than up-conversion to an intermediate frequency to exclude flicker noise. Meanwhile, utilizing fast-scanning MEMS mirrors, high-quality real-time (1 fps) 4-D images of the slow-moving object (10 mm/s) can be directly constructed at the baseband with a central frequency as low as 100 kHz and a small Doppler shift. The proposed LiDAR architecture based on such a low-frequency baseband significantly improves the optical power budget on the transmitter side and eliminates the costly high-speed sampling circuits on the receiver side.

Megakaryocytic IGF1 coordinates activation and ferroptosis to safeguard hematopoietic stem cell regeneration after radiation injury.

BACKGROUND: Hematopoietic stem cell (HSC) regeneration underlies hematopoietic recovery from myelosuppression, which is a life-threatening side effect of cytotoxicity. HSC niche is profoundly disrupted after myelosuppressive injury, while if and how the niche is reshaped and regulates HSC regeneration are poorly understood. METHODS: A mouse model of radiation injury-induced myelosuppression was built by exposing mice to a sublethal dose of ionizing radiation. The dynamic changes in the number, distribution and functionality of HSCs and megakaryocytes were determined by flow cytometry, immunofluorescence, colony assay and bone marrow transplantation, in combination with transcriptomic analysis. The communication between HSCs and megakaryocytes was determined using a coculture system and adoptive transfer. The signaling mechanism was investigated both in vivo and in vitro, and was consolidated using megakaryocyte-specific knockout mice and transgenic mice. RESULTS: Megakaryocytes become a predominant component of HSC niche and localize closer to HSCs after radiation injury. Meanwhile, transient insulin-like growth factor 1 (IGF1) hypersecretion is predominantly provoked in megakaryocytes after radiation injury, whereas HSCs regenerate paralleling megakaryocytic IGF1 hypersecretion. Mechanistically, HSCs are particularly susceptible to megakaryocytic IGF1 hypersecretion, and mTOR downstream of IGF1 signaling not only promotes activation including proliferation and mitochondrial oxidative metabolism of HSCs, but also inhibits ferritinophagy to restrict HSC ferroptosis. Consequently, the delicate coordination between proliferation, mitochondrial oxidative metabolism and ferroptosis ensures functional HSC expansion after radiation injury. Importantly, punctual IGF1 administration simultaneously promotes HSC regeneration and hematopoietic recovery after radiation injury, representing a superior therapeutic approach for myelosuppression. CONCLUSIONS: Our study identifies megakaryocytes as a last line of defense against myelosuppressive injury and megakaryocytic IGF1 as a novel niche signal safeguarding HSC regeneration.

Should Patients with Renal Cell Carcinoma and Pathological Nodal Invasion Be Classified As Having Stage IV Disease?

BACKGROUND: Lymph node invasion is associated with poor outcome in patients with renal cell carcinoma (RCC). PATIENTS AND METHODS: Patients with RCC within a single center from 2001 to 2018 were retrospectively obtained from the Chang Gung Research Database. Patient gender, physical status, Charlson Comorbidity Index, tumor side, histology, age at diagnosis, and body mass index (BMI) were compared. The overall survival (OS) and cancer-specific survival (CSS) of each group were estimated using the Kaplan-Meier method. Log-rank tests were used to compare between the subgroups. RESULTS AND CONCLUSIONS: A total of 335 patients were enrolled, of whom 76 had pT3N0M0, 29 had pT1-3N1M0, 104 had T1-4N0M1, and 126 had T1-4N1M1 disease. Significant OS difference was noted between pT3N0M0 and pT1-3N1M0 groups with 12.08 years [95% confidence interval (CI), 8.33-15.84] versus 2.58 years (95% CI, 1.32-3.85), respectively (P < 0.005). No significant difference was observed in OS between pT1-3N1M0 and T1-4N0M1 groups with 2.58 years (95% CI, 1.32-3.85) versus 2.50 years (95% CI, 1.85-3.15, P = 0.72). The OS of N1M1 group was worse than that of N0M1 group with 1.00 year (95% CI, 0.74-1.26) versus 2.50 years (95% CI, 1.85-3.15, P < 0.05). Similar results were also observed in CSS. In summary, we claim that RCC with lymph node (LN) invasion should be reclassified as stage IV disease in terms of survival outcome.

Total Synthesis of Resiniferatoxin.

From both structural and functional perspectives, the large family of daphnane diterpene orthoesters (DDOs) represent a truly remarkable class of natural products. As potent lead compounds for the treatment of pain, neurodegeneration, HIV/AIDS, and cancer, their medicinal potential continues to be heavily investigated, yet synthetic routes to DDO natural products remain rare. Herein we report a distinct approach to this class of complex diterpenes, highlighted by a 15-step total synthesis of the flagship DDO, resiniferatoxin.

Impact of intratumoural CD96 expression on clinical outcome and therapeutic benefit in gastric cancer.

CD96 was identified as a novel immune checkpoint. However, the role of CD96 in the gastric cancer (GC) microenvironment remains fragmentary. This study aimed to probe the clinical significance of CD96 to predict prognosis and therapeutic responsiveness, and to reveal the immune contexture and genomic features correlated to CD96 in GC patients. We enrolled 496 tumor microarray specimens of GC patients from Zhongshan Hospital (ZSHS) for immunohistochemical analyses. Four hundred and twelve GC patients from the Cancer Genome Atlas (TCGA) and 61 GC patients treated with pembrolizumab from ERP107734 published in the European Nucleotide Archive (ENA) were gathered for further analysis of the association between CD96+ cell infiltration and immune contexture, molecular characteristics, and genomic features by CIBERSORT and gene set enrichment analysis. Clinical outcomes were analyzed by Kaplan-Meier curves, the Cox model, interaction testing, and receiver operating characteristic analysis. High CD96+ cell infiltration predicted poor prognosis and inferior survival benefits from fluorouracil-based adjuvant chemotherapy in the ZSHS cohort whereas superior therapeutic responsiveness to pembrolizumab was shown in the ENA cohort. CD96-enriched tumors showed an immunosuppressive tumor microenvironment featured by exhausted CD8+ T-cell infiltration in both the ZSHS and TCGA cohorts. Moreover, in silico analysis for the TCGA cohort revealed that several biomarker-targeted pathways displayed significantly elevated enrichment levels in the CD96 high subgroup. This study elucidated that CD96 might drive an immunosuppressive contexture with CD8+ T-cell exhaustion and represent an independent adverse prognosticator in GC. CD96 could potentially be a novel biomarker for precision medicine of adjuvant chemotherapy, immunotherapy, and targeted therapies in GC.

Intratumoral PD-1+CD8+ T cells associate poor clinical outcomes and adjuvant chemotherapeutic benefit in gastric cancer.

BACKGROUND: Although PD-1 has been reported to be a marker of T-cell exhaustion in several malignancies, the biological role of PD-1+CD8+ T cells in gastric cancer (GC) remains unclear. Herein, we aimed to investigate the role of PD-1+CD8+ T cells in the tumour microenvironment and its clinical significance in GC. DESIGNS: This study included 441 tumour microarray specimens and 60 Flow cytometry specimens of GC patients from Zhongshan Hospital, and 250 GC patients from the Asian Cancer Research Group. RESULTS: Here, we demonstrated that PD-1+CD8+ T cells functioned as an independent adverse prognosticator in GC. In addition, an abundance of intratumoral PD-1+CD8+ T cells indicated worse chemotherapeutic responsiveness to fluorouracil in Stage III GC patients. Mechanistically, PD-1+CD8+ T cell high infiltration indicated an exhausted phenotype of global CD8+ T cells in GC tissues, which was characterised by elevated immune checkpoint expression including CTLA-4 and TIM-3, whereas decreased expression of perforin. Furthermore, PD-1+CD8+ T cell high-infiltration patients with Stage III GC held elevated activity of several therapeutic signal pathways. CONCLUSIONS: Our study highlighted that PD-1+CD8+ T cell abundance predicts inferior prognosis in GC, and may serve as a novel predictive biomarker to guide therapeutic option.

Latency-associated Peptide Identifies Immunoevasive Subtype Gastric Cancer With Poor Prognosis and Inferior Chemotherapeutic Responsiveness.

OBJECTIVE: To examine the clinical significance of LAP to predict survival outcomes and chemotherapeutic responsiveness in gastric cancer. BACKGROUND: LAP has been shown to possess significant immunoregulatory roles in several malignancies. However, the role and clinical significance of LAP in gastric cancer still remains unknown. METHODS: Four hundred and fifty-six tumor tissue microarray specimens, 80 fresh tumor tissue samples of gastric cancer patients from Zhongshan Hospital, Fudan University and transcriptomic and clinical data of 328 gastric cancer patients from the Cancer Genome Atlas were analyzed. LAP expression and immune contexture were examined by immunohistochemistry, CIBERSORT, and flow cytometry. Clinical outcomes of patient subgroups were compared by Kaplan-Meier curves, Cox model and interaction test. RESULTS: High LAP expression predicted poor overall survival (P < 0.001, P < 0.001, and P = 0.022) and inferior therapeutic responsiveness to fluorouracil-based adjuvant chemotherapy (P = 0.008 for interaction) in gastric cancer. LAP was associated with immunoevasive tumor microenvironment featured by dysfunctional CD8+ T cells infiltration (P < 0.001). The LAP-associated dysfunctional CD8+ T cells had an exhausted phenotype with decreased effector molecules such as interferon-γ, granzyme B, and perforin, but also elevated programmed cell death protein-1, which resulted in poor prognosis and inferior therapeutic responsiveness. CONCLUSIONS: This study revealed that LAP could identify immunoevasive subtype gastric cancer, indicating LAP might be a potential immunotherapeutic target and facilitate patient counseling on individualized adjuvant therapy and follow-up scheduling in gastric cancer.

Asymmetric Total Syntheses of (+)-Davisinol and (+)-18-Benzoyldavisinol: A HAT-Initiated Transannular Redox Radical Approach.

The first and asymmetric total syntheses of two C11-oxygenated hetisine-type diterpenoid alkaloids, namely, (+)-davisinol and (+)-18-benzoyldavisinol, is described. The concise synthetic approach features a HAT-initiated transannular redox radical cyclization, an ODI-Diels-Alder cycloaddition, and an acylative kinetic resolution. By incorporating an efficient late-stage assembly of the azabicycle, our strategy would streamline the synthetic design of C20-diterpenoid alkaloids and pave the way for their modular syntheses.

The 14-3-3η chaperone protein promotes antiviral innate immunity via facilitating MDA5 oligomerization and intracellular redistribution.

MDA5 belongs to the RIG-I-like receptor family and plays a non-redundant role in recognizing cytoplasmic viral RNA to induce the production of type I IFNs. Upon RNA ligand stimulation, we observed the redistribution of MDA5 from the cytosol to mitochondrial membrane fractions. However, the molecular mechanisms of MDA5 activation remain less understood. Here we show that 14-3-3η is an essential accessory protein for MDA5-dependent type I IFN induction. We found that several 14-3-3 isoforms may interact with MDA5 through the CARDs (N-MDA5), but 14-3-3η was the only isoform that could enhance MDA5-dependent IFNß promoter activities in a dose-dependent manner. Knock-down of 14-3-3η in Huh7 cells impaired and delayed the kinetics of MDA5 oligomerization, which is a critical step for MDA5 activation. Consequently, the MDA5-dependent IFNß promoter activities as well as IFNß mRNA expression level were also decreased in the 14-3-3η knocked-down cells. We also demonstrated that 14-3-3η is essential in boosting the activation of MDA5-dependent antiviral innate immunity during viral infections. In conclusion, our results uncover a novel function of 14-3-3η to promote the MDA5-dependent IFNß induction pathway by reducing the immunostimulatory potential of viral dsRNA within MDA5 activation signaling pathway.

Clinical Outcomes and Immune Metrics in Intratumoral Basophil-Enriched Gastric Cancer Patients.

BACKGROUND: Accumulation of basophils has been reported in several malignancies. In gastric cancer, the relation between tumor-infiltrating basophils and patient overall survival and chemotherapeutic responsiveness still remains obscure. OBJECTIVE: We aimed to investigate the postoperative prognostic and predictive significance of basophils to survival outcomes and chemotherapeutic responsiveness in resectable gastric cancer. METHODS: The study enrolled two independent patient data sets with 448 gastric cancer patients overall. Basophils were evaluated with the use of immunohistochemistry (IHC) staining, and the correlation with clinicopathological characteristics, survival outcomes, and responsiveness to fluorouracil-based adjuvant chemotherapy (ACT) were investigated. Additionally, IHC was applied to characterize immune contexture in gastric cancer. RESULTS: In either the discovery or validation data sets, accumulated basophils indicated poorer prognosis, and tumor-infiltrating basophils were identified as an independent adverse prognostic factor by multivariate analysis. Furthermore, tumor-infiltrating basophils determined significantly inferior therapeutic responsiveness to fluorouracil-based ACT in patients with stage III tumors. In addition, the abundance of basophils was correlated with an immunoevasive contexture characterized by M2-polarized macrophage infiltration. Moreover, our findings indicated elevated interleukin-4 expression but decreased interferon-γ expression in the high-basophils subgroup. CONCLUSIONS: Tumor-infiltrating basophils in gastric cancer were identified as an independent adverse prognosticator, and also predicted inferior chemotherapeutic responsiveness, which identified those patients in need of much more individualized postoperative adjuvant therapy and more stringent follow-up. Furthermore, the infiltration of basophils was associated with immunoevasive tumor microenvironment, which might be a potential immunotherapeutic target for gastric cancer.

SFRP4 drives invasion in gastric cancer and is an early predictor of recurrence.

OBJECTIVE: Gastric cancer patients generally have a poor outcome, particularly those with advanced-stage disease which is defined by the increased invasion of cancer locally and is associated with higher metastatic potential. This study aimed to identify genes that were functional in the most fundamental hallmark of cancer, namely invasion. We then wanted to assess their value as biomarkers of gastric cancer progression and recurrence. DESIGN: Data from a cohort of patients profiled on cDNA expression arrays was interrogated using K-means analysis. This genomic approach classified the data based on patterns of gene expression allowing the identification of the genes most correlated with the invasion of GC. We evaluated the functional role of a key protein from this analysis in invasion and as a biomarker of recurrence after curative resection. RESULTS: Expression of secreted frizzled-related protein 4 (SFRP4) was identified as directly proportional to gastric cancer invasion. This finding was validated in multiple, independent datasets and its functional role in invasion was also confirmed using invasion assays. A change in serum levels of SFRP4 after curative resection, when coupled with AJCC stage, can accurately predict the risk of disease recurrence after curative therapy in an assay we termed PredictR. CONCLUSIONS: This simple ELISA-based assay can help predict recurrence of disease after curative gastric cancer surgery irrespective of adjuvant therapy. The results require further evaluation in a prospective trial but would help in the rational prescription of cancer therapies and surveillance to prevent under or over treatment of patients after curative resection.

Significantly reducing blood loss via a peri-articular injection of tranexamic acid during total knee arthroplasty: a retrospective study.

BACKGROUND: The administration of an intra-articular injection (IAI) of tranexamic acid (TXA) has been demonstrated to be effective in reducing both blood loss and transfusion rate during total knee arthroplasty (TKA); however, few studies have reported the efficiency of a peri-articular injection (PAI) of TXA. We studied the efficiency of a PAI of TXA in reducing blood loss during TKA. METHODS: Fifty patients undergoing primary simultaneous bilateral TKA were enrolled in this retrospective study. The right knee received a PAI of 1 g of TXA (Group I), and the left knee received an IAI of 1 g of TXA (Group II). The clinical outcome measures were a change in blood loss from Hemovac drains and surgical time. RESULTS: The decrease in blood loss from the Hemovac was significantly lower in Group I (460.1 ± 36.79 vs. 576.0 ± 34.01, P < 0.001) than in Group II, and no significant difference in surgical times was observed. The blood transfusion rate in the present study was 16 %. CONCLUSIONS: A PAI of TXA may reduce blood loss more efficiently than an IAI of TXA during TKA without increased complications such as surgical site infection, poor wound healing, skin necrosis, pulmonary embolism, and deep vein thrombosis.

Comparable outcomes of recycled autografts and allografts for reconstructions in patients with high-grade osteosarcoma.

PURPOSE: This retrospective, single-centre study compares the clinical and radiographic outcomes of limb reconstruction using recycled autografts to that using allografts. METHODS: Patients with histopathologically verified high-grade osteosarcoma treated with wide bone resection and limb reconstruction using allografts or recycled autografts from January 1998 through December 2012 were retrospectively screened for enrolment eligibility. The final study cohort included 255 patients (allograft, 91; recycled autograft, 164). Data regarding post-operative complications, salvage treatment, and graft survival were collected. A modified International Society of Limb Salvage classification system was used to evaluate the radiographic findings. RESULTS: The time to graft-host union did not differ significantly between the two graft types. Patients receiving recycled autografts had fewer complications compared than did those receiving allografts (recycled autografts vs. allograft: structural failure, 4.3 vs. 13.2%; late infection, 2.4 vs. 7.7%; all p < 0.05). Complications occurred most frequently during the first three years after surgery, and the majority were manageable. The five year limb survival rate did not differ significantly between the two graft types (91.3 vs. 94.0%; p = 0.752). No local oncological recurrence was observed within the recycled autografts. CONCLUSION: Recycled autografts and allografts are feasible options for biological limb reconstructions in terms of complications and graft survival after wide resection of osteosarcoma.

Identification and validation of an immunogenic subtype of gastric cancer with abundant intratumoural CD103+CD8+ T cells conferring favourable prognosis.

BACKGROUND: Intratumoural CD103+CD8+ T cells have been linked to prolonged survival in several malignancies. However, the clinical significance of CD103+CD8+ T cells in gastric cancer remains unexplored. METHODS: Gastric cancer tissues from Zhongshan Hospital and data from Gene Expression Omnibus were obtained and analysed. Immunohistochemistry and flow cytometry were performed to detect the number and phenotypical characteristics of CD103+CD8+ T cells. The effect of programmed cell death protein-1 (PD-1) blockade on CD103+CD8+ T cells was evaluated with the use of an in vitro study based on fresh tumour tissues. RESULTS: CD103+CD8+ T cells predicted superior overall survival and provided better prognostic power than total CD8+ T cells in gastric cancer. Patients with high CD103+CD8+ T cell infiltration also gained more benefit from adjuvant chemotherapy. Flow cytometry analysis showed that CD103+CD8+ T cells exerted superior anti-tumour effects with stronger retention capacity and cytotoxicity. Moreover, an in vitro study showed that CD103+CD8+ T cells were more functionally restored after PD-1 blockade than CD103-CD8+ T cells. CONCLUSIONS: CD103+CD8+ T cells might be a useful marker to predict prognosis and therapeutic efficacy for gastric cancer patients. Efforts to increase intratumoural CD103+CD8+ T cell frequency might be a novel therapeutic strategy in gastric cancer.

Lauren classification identifies distinct prognostic value and functional status of intratumoral CD8+ T cells in gastric cancer.

With dichotomous etiology and pathogenesis, intestinal type and diffuse type gastric cancers vary in their clinical and molecular features to the point of representing distinct entities. However, the differences of tumor-infiltrating immune cells within the two types of gastric cancer have not been well researched. This study was aimed to evaluate the functional impact of Lauren classification on immune contexture in gastric cancer patients. Tumor tissues of gastric cancer patients from Zhongshan Hospital and gastric cancer data from The Cancer Genome Atlas (TCGA) cohort were analyzed. By immunohistochemistry and flow cytometry, we found that intratumoral CD8+ T cells were more abundant but less functional in diffuse type as compared with those in intestinal type tumor tissues. Survival analysis indicated that CD8+ T cells yielded favorable prognosis only in intestinal type patients other than diffuse type cancer patients. Moreover, such diffuse type-associated CD8+ T cell dysfunction was featured by elevated expression of immunosuppressive factors including interleukin-10 (IL-10), transforming growth factor-ß1 (TGF-ß1) and indoleamine 2,3-dioxygenase 1 (IDO1). In summary, we found that the density, prognostic significance and functional status of intratumoral CD8+ T cells varied with Lauren subtypes in gastric cancer. These results further indicated Lauren classification might be a potential therapeutic marker, and should be considered in therapeutic decisions, especially immunotherapeutic eligibility.

A Noncanonical Basic Motif of Epstein-Barr Virus ZEBRA Protein Facilitates Recognition of Methylated DNA, High-Affinity DNA Binding, and Lytic Activation.

The pathogenesis of Epstein-Barr virus (EBV) infection, including development of lymphomas and carcinomas, is dependent on the ability of the virus to transit from latency to the lytic phase. This conversion, and ultimately disease development, depends on the molecular switch protein, ZEBRA, a viral bZIP transcription factor that initiates transcription from promoters of viral lytic genes. By binding to the origin of viral replication, ZEBRA is also an essential replication protein. Here, we identified a novel DNA-binding motif of ZEBRA, N terminal to the canonical bZIP domain. This RRTRK motif is important for high-affinity binding to DNA and is essential for recognizing the methylation state of viral promoters. Mutations in this motif lead to deficiencies in DNA binding, recognition of DNA methylation, lytic cycle DNA replication, and viral late gene expression. This work advances our understanding of ZEBRA-dependent activation of the viral lytic cascade.IMPORTANCE The binding of ZEBRA to methylated and unmethylated viral DNA triggers activation of the EBV lytic cycle, leading to viral replication and, in some patients, cancer development. Our work thoroughly examines how ZEBRA uses a previously unrecognized basic motif to bind nonmethylated and methylated DNA targets, leading to viral lytic activation. Our findings show that two different positively charged motifs, including the canonical BZIP domain and a newly identified RRTRK motif, contribute to the mechanism of DNA recognition by a viral AP-1 protein. This work contributes to the assessment of ZEBRA as a potential therapeutic target for antiviral and oncolytic treatments.

An investigation of the anomalous asymptotic behavior of elastic electron scattering of helium.

For the inelastic electron scattering of atoms and molecules, a consensus has been reached that the first Born approximation is easily approached by decreasing the momentum transfer at the same impact electron energy or increasing the impact electron energy at the same momentum transfer. Although this consensus is applicable for the elastic electron scattering of most atoms and molecules, it is violated for helium where the experimental differential cross sections deviate from the first Born approximation prediction gradually with the decrease of squared momentum transfer at the same impact electron energy. Since this anomalous phenomenon was observed more than 40 years ago, the intrinsic mechanism is not explicit. In the present work, using the high-resolution x-ray scattering, we isolate the scattering contribution from the nucleus and directly obtain the pure electronic structure of helium. Then, the anomalous asymptotic behavior of the elastic electron scattering of helium has been elucidated, i.e., in the small squared momentum transfer region, the scattering contribution from the target's electrons is counteracted by the one from the atomic nucleus, which results in the residual contribution beyond the first Born approximation being drastically enlarged.

Mutant Cellular AP-1 Proteins Promote Expression of a Subset of Epstein-Barr Virus Late Genes in the Absence of Lytic Viral DNA Replication.

Epstein-Barr virus (EBV) ZEBRA protein activates the EBV lytic cycle. Cellular AP-1 proteins with alanine-to-serine [AP-1(A/S)] substitutions homologous to ZEBRA(S186) assume some functions of EBV ZEBRA. These AP-1(A/S) mutants bind methylated EBV DNA and activate expression of some EBV genes. Here, we compare expression of 67 viral genes induced by ZEBRA versus expression induced by AP-1(A/S) proteins. AP-1(A/S) activated 24 genes to high levels and 15 genes to intermediate levels; activation of 28 genes by AP-1(A/S) was severely impaired. We show that AP-1(A/S) proteins are defective at stimulating viral lytic DNA replication. The impairment of expression of many late genes compared to that of ZEBRA is likely due to the inability of AP-1(A/S) proteins to promote viral DNA replication. However, even in the absence of detectable viral DNA replication, AP-1(A/S) proteins stimulated expression of a subgroup of late genes that encode viral structural proteins and immune modulators. In response to ZEBRA, expression of this subgroup of late genes was inhibited by phosphonoacetic acid (PAA), which is a potent viral replication inhibitor. However, when the lytic cycle was activated by AP-1(A/S), PAA did not reduce expression of this subgroup of late genes. We also provide genetic evidence, using the BMRF1 knockout bacmid, that these genes are true late genes in response to ZEBRA. AP-1(A/S) binds to the promoter region of at least one of these late genes, BDLF3, encoding an immune modulator.IMPORTANCE Mutant c-Jun and c-Fos proteins selectively activate expression of EBV lytic genes, including a subgroup of viral late genes, in the absence of viral DNA replication. These findings indicate that newly synthesized viral DNA is not invariably required for viral late gene expression. While viral DNA replication may be obligatory for late gene expression driven by viral transcription factors, it does not limit the ability of cellular transcription factors to activate expression of some viral late genes. Our results show that expression of all late genes may not be strictly dependent on viral lytic DNA replication. The c-Fos A151S mutation has been identified in a human cancer. c-Fos A151S in combination with wild-type c-Jun activates the EBV lytic cycle. Our data provide proof of principle that mutant cellular transcription factors could cause aberrant regulation of viral lytic cycle gene expression and play important roles in EBV-associated diseases.