Repression of rRNA gene transcription by endothelial SPEN deficiency normalizes tumor vasculature via nucleolar stress

Human cancers induce a chaotic, dysfunctional vasculature that promotes tumor growth and blunts most current therapies; however, the mechanisms underlying the induction of a dysfunctional vasculature have been unclear. Here, we show that split end (SPEN), a transcription repressor, coordinates rRNA synthesis in endothelial cells (ECs) and is required for physiological and tumor angiogenesis. SPEN deficiency attenuated EC proliferation and blunted retinal angiogenesis, which was attributed to p53 activation. Furthermore, SPEN knockdown activated p53 by upregulating noncoding promoter RNA (pRNA), which represses rRNA transcription and triggers p53-mediated nucleolar stress. In human cancer biopsies, a low endothelial SPEN level correlated with extended overall survival. In mice, endothelial SPEN deficiency compromised rRNA expression and repressed tumor growth and metastasis by normalizing tumor vessels, and this was abrogated by p53 haploinsufficiency. rRNA gene transcription is driven by RNA polymerase I (RNPI). We found that CX-5461, an RNPI inhibitor, recapitulated the effect of Spen ablation on tumor vessel normalization and combining CX-5461 with cisplatin substantially improved the efficacy of treating tumors in mice. Together, these results demonstrate that SPEN is required for angiogenesis by repressing pRNA to enable rRNA gene transcription and ribosomal biogenesis and that RNPI represents a target for tumor vessel normalization therapy of cancer.

Staminal hairs increase pollinator attraction and pollination accuracy in Tradescantia fluminensis (Commelinaceae)

Staminal hairs are the particular appendages of stamens, which may affect pollinator foraging behaviour and pollen transfer. However, experimental evidence of the functions of staminal hairs in pollination remains scarce. Here, we conducted staminal hair manipulation experiments in Tradescantia fluminensis (Commelinaceae) to investigate their effects on visitation and pollen transfer by bees. Our observations revealed that both visitation rates and visit duration of honeybees (Apis cerana) to control flowers were significantly higher than that of hairless flowers. Moreover, removing the staminal hairs significantly decreased pollen deposition by honeybees (A. cerana), but did not affect pollen removal. The staminal hair was similar in length to the stamen and the pistil of T. fluminensis. The staminal hairs provide more footholds for honeybees, and they lay prone on the staminal hairs to collect pollen, which increased the accuracy of pollination through the consistent pollen placement and pick-up on the ventral surface of honeybees. These results showed that the staminal hairs in T. fluminensis may represent an adaptation to attract pollinators and enhance pollination accuracy.

Persistent calyces increase floral longevity and female fitness in Salvia miltiorrhiza (Lamiaceae)

The evolution of persistent calyces may be an adaptation to ensure reproductive success of certain flowering plants. However, experimental evidence of the functions of persistent calyces during flowering and seed development remains scarce. We explored the possible functions of persistent calyces in Salvia miltiorrhiza, a perennial herb with campanulate calyx. We conducted calyx manipulation experiments to examine whether persistent calyces affect visitation rates of nectar robbers and pollinators, individual flower longevity, fruit set, seed set and seed mass. Our findings suggested that shortening of the calyx significantly decreased individual flower longevity, fruit set and seed mass, but did not affect visitation of pollinators and nectar robbers. In addition, the seed set of control flowers and the flowers with calyx shortened at the beginning of fruiting stage (CSF flowers) did not significantly differ, but both were higher than that of the flowers with calyx shortened at the beginning of blooming stage (CSB flowers). The seed set and fruit set of CSB flowers were limited by pollination due to the reduction in floral longevity. We conclude that persistent calyces of S. miltiorrhiza may represent adaptive strategies to maintain floral longevity and increase plant fitness. Persistent calyces may provide protection for the growth of flowers and contribute resources to the development of fruits and seeds.

Notch activation promotes endothelial quiescence by repressing MYC expression via miR-218

After angiogenesis-activated embryonic and early postnatal vascularization, endothelial cells (ECs) in most tissues enter a quiescent state necessary for proper tissue perfusion and EC functions. Notch signaling is essential for maintaining EC quiescence, but the mechanisms of action remain elusive. Here, we show that microRNA-218 (miR-218) is a downstream effector of Notch in quiescent ECs. Notch activation upregulated, while Notch blockade downregulated, miR-218 and its host gene Slit2, likely via transactivation of the Slit2 promoter. Overexpressing miR-218 in human umbilical vein ECs (HUVECs) significantly repressed cell proliferation and sprouting in vitro. Transcriptomics showed that miR-218 overexpression attenuated the MYC proto-oncogene, bHLH transcription factor (MYC, also known as c-myc) signature. MYC overexpression rescued miR-218-mediated proliferation and sprouting defects in HUVECs. MYC was repressed by miR-218 via multiple mechanisms, including reduction of MYC mRNA, repression of MYC translation by targeting heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1), and promoting MYC degradation by targeting EYA3. Inhibition of miR-218 partially reversed Notch-induced repression of HUVEC proliferation and sprouting. In vivo, intravitreal injection of miR-218 reduced retinal EC proliferation accompanied by MYC repression, attenuated pathological choroidal neovascularization, and rescued retinal EC hyper-sprouting induced by Notch blockade. In summary, miR-218 mediates the effect of Notch activation of EC quiescence via MYC and is a potential treatment for angiogenesis-related diseases.

[Special histopathological variants and potential diagnostic traps of classical follicular dendritic cell sarcoma]

Objective: To investigate the clinicopathological features, special morphologic variants and potential diagnostic traps of classical follicular dendritic cell sarcoma (FDCS). Methods: A total of 25 cases of classical FDCS diagnosed in the First Hospital Affiliated to Army Medical University from 2006 to 2018 were examined by hematoxylin-eosin staining, immunohistochemistry and in situ hybridization for Epstein-Barr virus-encoded mRNA (EBER). Meanwhile, the types and characteristics of the special variants of FDCS were summarized along with those reported in the literature. Results: The age of patients ranged from 23 to 77 years (mean 52 years), the male to female ratio was 1.5, and the maximum diameter of tumor was 1.5 to 20 cm (mean 7.4 cm). Twelve cases (48%) were misdiagnosed at the initial evaluation. Follow-up information was available for 17 patients, and the follow-up time was 5 to 96 months. The propotion of patients having recurrence, metastasis and mortality was 3/17, 5/17 and 2/17, respectively. Microscopically, besides the typical morphology, 10 cases of FDCS showed special histomorphologies and/or structures, including those mimicking lymphoepithelioma-like carcinoma, desmoplastic infiltrating carcinoma, classical Hodgkin's lymphoma (CHL), anaplastic large cell lymphoma (ALCL) and hemangiopericytoma. These morphologic variants were potential diagnostic pitfalls and warranted attention. Immunohistochemistry showed that more than two markers of follicular dendritic cells (such as CD21, CD23, CD35, etc.) were expressed in cases showing typical morphology and the special variants. All 25 cases were all negative for EBER by in situ hybridization. Conclusions: Classical FDCS is rare, besides the typical morphologic features, there are many special variants. In particular, these may be confused with lymphoepithelioma-like carcinoma in the nasopharynx, CHL or ALCL in the mediastinum/lymph node. Awareness of these variants is essential for accurate diagnosis.

[Consistency of ALK Ventana-D5F3 immunohistochemistry interpretation in lung adenocarcinoma among Chinese histopathologists]

Objective: To understand the consistency of ALK Ventana-D5F3 immunohistochemistry (IHC) interpretation in Chinese lung adenocarcinoma among histopathologists from different hospitals, and to recommend solution for the problems found during the interpretation of ALK IHC in real world, with the aim of the precise selection of patients who can benefit from ALK targeted therapy. Methods: This was a multicenter and retrospective study. A total of 109 lung adenocarcinoma cases with ALK Ventana-D5F3 IHC staining were collected from 31 lung cancer centers in RATICAL research group from January to June in 2018. All cases were scanned into digital imaging with Ventana iSCANcoreo Digital Slide Scanning System and scored by 31 histopathologists from different centers according to ALK binary (positive or negative) interpretation based on its manufacturer's protocol. The cases with high inconsistency rate were further analyzed using FISH/RT-PCR/NGS. Results: There were 49 ALK positive cases and 60 ALK negative cases, confirmed by re-evaluation by the specialist panel. Two cases (No. 2302 and No.2701) scored as positive by local hospitals were rescored as negative, and were confirmed to be negative by RT-PCR/FISH/NGS. The false interpretation rate of these two cases was 58.1% (18/31) and 48.4% (15/31), respectively. Six out of 31 (19.4%) pathologists got 100% accuracy. The minimum consistency between every two pathologists was 75.8%.At least one pathologist gave negative judgement (false negative) or positive judgement (false positive) in the 49 positive or 60 negative cases, accounted for 26.5% (13/49), 41.7% (25/60), respectively, with at least one uncertainty interpretation accounted for 31.2% (34/109). Conclusion: There are certain heterogeneities and misclassifications in the real world interpretation of ALK-D5F3 IHC test, which need to be guided by the oncoming expert consensus based on the real world data.

[Research advances in the v-raf murine sarcoma viral oncogene homolog gene mutation in ameloblastoma]

V-raf murine sarcoma viral oncogene homolog B1 (BRAF) is a pro-oncogene, which is one member of the RAF family. Mutated BRAF is found in approximately 8% of human tumors. BRAF gene mutations lead to continuous activation of the mitogen-activatd protein kinase (MAPK) pathway, which resulting in abnormal cell proliferation and tumorigenesis. In recent years, recurrent MAPK signaling mutations were identified in ameloblastoma, among which BRAF-V600E is the most prominent type. This provides new strategies for the targeted treatment of ameloblastoma. This paper reviewed the latest advances in BRAF gene mutation associated with ameloblastoma and its potential clinical significance.

[Clinicopathologic features and prognosis of inflammatory pseudotumor-like follicular dendritic cell sarcomas in liver and spleen: an analysis of seven cases]

Objective: To investigate the clinicopathological features and prognostic parameters of the inflammatory pseudotumor-like follicular dendritic cell sarcoma (IPT-like FDCS) of liver and spleen. Methods: Ninteen cases of inflammatory pseudotumor (IPT) and 5 cases of IPT-like FDCS of the liver and spleen were collected at the First Affiliated Hospital, Army Medical University from 2006 to 2016. HE sections, immunohistochemical staining, and Epstein-Barr virus encoded nuclear RNA (EBER) in situ hybridization were reviewed along with a summary of the literature. Results: Among the previously diagnosed 19 cases of IPT of the liver and spleen, 2 cases were misdiagnosed (the ratio of 2/19). Among 7 new cases including 3 males and 4 females, 3 cases involved the liver and 4 cases involved the spleen. The age range was 37-64 years (mean 53 years). The maximum tumor diameter ranged from 3.0 to 11.0 cm (mean 6.5 cm). Surgical resections were performed in all patients with follow-up time ranging from 3 to 84 months.All patients were disease-free.7 new cases were all positive for EBER, and showed the expression of at least one of the FDC markers, including CD21, CD23, and CD35. The rest of 17 cases of IPT were all negative for EBER and essentially negative for FDC markers, but were all positive for SMA. Conclusions: IPT-like FDCS of the liver and spleen is a rare low-grade malignant tumor morphologically mimicking inflammatory pseudotumor, and is easy to be misdiagnosis due to under-recognition. EBER in situ hybridization and FDC markers are indispensable for confirming the diagnosis.

[The understanding of Epstein-Barr virus associated lymphoproliferative disorder]

In recent years, there are increasing articles concerning Epstein-Barr virus associated lymphoproliferative disorder (EBV+ LPD), and the name of EBV+ LPD is used widely. However, the meaning of EBV+ LPD used is not the same, which triggered confusion of the understanding and obstacles of the communication. In order to solve this problem. Literature was reviewed with combination of our cases to clarify the concept of EBV+ LPD and to expound our understanding about it. In general, it is currently accepted that EBV+ LPD refers to a spectrum of lymphoid tissue diseases with EBV infection, including hyperplasia, borderline lesions, and neoplastic diseases. According to this concept, EBV+ LPD should not include infectious mononucleosis (IM) and severe acute EBV infection (EBV+ hemophagocytic lymphohistiocytosis, fatal IM, fulminant IM, fulminant T-cell LPD), and should not include the explicitly named EBV+ lymphomas (such as extranodal NK/T cell lymphoma, aggressive NK cell leukemia, Burkitt lymphoma, and Hodgkin lymphoma, etc.) either. EBV+ LPD should currently include: (1) EBV+ B cell-LPD: lymphomatoid granulomatosis, EBV + immunodeficiency related LPD, chronic active EBV infection-B cell type, senile EBV+ LPD, etc. (2) EBV+ T/NK cell-LPD: CAEBV-T/NK cell type, hydroa vacciniforme, hypersensitivity of mosquito bite, etc. In addition, EBV+ LPD is classified, based on the disease process, pathological and molecular data, as 3 grades: grade1, hyperplasia (polymorphic lesions with polyclonal cells); grade 2, borderline (polymorphic lesions with clonality); grade 3, neoplasm (monomorphic lesions with clonality). There are overlaps between EBV+ LPD and typical hyperplasia, as well as EBV+ LPD and typical lymphomas. However, the most important tasks are clinical vigilance, early identification of potential severe complications, and treating the patients in a timely manner to avoid serious complications, as well as the active treatment to save lives when the complications happened.

miR-342-5p Regulates Neural Stem Cell Proliferation and Differentiation Downstream to Notch Signaling in Mice

Notch signaling is critically involved in neural development, but the downstream effectors remain incompletely understood. In this study, we cultured neurospheres from Nestin-Cre-mediated conditional Rbp-j knockout (Rbp-j cKO) and control embryos and compared their miRNA expression profiles using microarray. Among differentially expressed miRNAs, miR-342-5p showed upregulated expression as Notch signaling was genetically or pharmaceutically interrupted. Consistently, the promoter of the miR-342-5p host gene, the Ena-vasodilator stimulated phosphoprotein-like (Evl), was negatively regulated by Notch signaling, probably through HES5. Transfection of miR-342-5p promoted the differentiation of neural stem cells (NSCs) into intermediate neural progenitors (INPs) in vitro and reduced the stemness of NSCs in vivo. Furthermore, miR-342-5p inhibited the differentiation of neural stem/intermediate progenitor cells into astrocytes, likely mediated by targeting GFAP directly. Our results indicated that miR-342-5p could function as a downstream effector of Notch signaling to regulate the differentiation of NSCs into INPs and astrocytes commitment.

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miR-342-5p acts as a downstream effector of canonical Notch signaling

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Notch signal inhibits miR-342-5p expression by regulating its host gene Evl

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miR-342-5p promotes the transition of NSCs into INPs

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Astrocyte commitment was suppressed by miR-342-5p targeting GFAP

The Notch ligand delta-like 3 promotes tumor growth and inhibits Notch signaling in lung cancer cells in mice

Although it has been suggested that Dll3, one of the Notch ligands, promotes the proliferation and inhibits the apoptosis of cancer cells, the role of Dll3 in cancers remains unclear. In this study, we found that in the murine Lewis lung carcinoma (LLC) cells, the level of Dll3 mRNA changed upon tumor microenvironment (TME) stimulation, namely, decreased under hypoxia or stimulated with tumor necrosis factor (TNF)-α. Dll3 was also expressed at higher level in human lung carcinoma tissues than in the para-carcinoma tissues. Overexpression of Dll3 in LLC cells promoted cell proliferation and reduced apoptosis in vitro, and enhanced tumor growth when inoculated in vivo in mice. The Dll3-mediated proliferation could be due to increased Akt phosphorylation in LLC cells, because an Akt inhibitor counteracted Dll3-induced proliferation. Moreover, Dll3 overexpression promoted PI3K/Akt signaling through inhibiting Notch signaling.

miR-342-5p Is a Notch Downstream Molecule and Regulates Multiple Angiogenic Pathways Including Notch, Vascular Endothelial Growth Factor and Transforming Growth Factor β Signaling

Background

Endothelial cells (ECs) form blood vessels through angiogenesis that is regulated by coordination of vascular endothelial growth factor (VEGF), Notch, transforming growth factor β, and other signals, but the detailed molecular mechanisms remain unclear.

Methods and Results

Small RNA sequencing initially identified miR‐342‐5p as a novel downstream molecule of Notch signaling in ECs. Reporter assay, quantitative reverse transcription polymerase chain reaction and Western blot analysis indicated that miR‐342‐5p targeted endoglin and modulated transforming growth factor β signaling by repressing SMAD1/5 phosphorylation in ECs. Transfection of miR‐342‐5p inhibited EC proliferation and lumen formation and reduced angiogenesis in vitro and in vivo, as assayed by using a fibrin beads–based sprouting assay, mouse aortic ring culture, and intravitreal injection of miR‐342‐5p agomir in P3 pups. Moreover, miR‐342‐5p promoted the migration of ECs, accompanied by reduced endothelial markers and increased mesenchymal markers, indicative of increased endothelial–mesenchymal transition. Transfection of endoglin at least partially reversed endothelial–mesenchymal transition induced by miR‐342‐5p. The expression of miR‐342‐5p was upregulated by transforming growth factor β, and inhibition of miR‐342‐5p attenuated the inhibitory effects of transforming growth factor β on lumen formation and sprouting by ECs. In addition, VEGF repressed miR‐342‐5p expression, and transfection of miR‐342‐5p repressed VEGFR2 and VEGFR3 expression and VEGF‐triggered Akt phosphorylation in ECs. miR‐342‐5p repressed angiogenesis in a laser‐induced choroidal neovascularization model in mice, highlighting its clinical potential.

Conclusions

miR‐342‐5p acts as a multifunctional angiogenic repressor mediating the effects and interaction among angiogenic pathways.

Notch signaling in blood vessels: from morphogenesis to homeostasis

Notch signaling is an evolutionarily conserved intercellular signaling pathway that plays numerous crucial roles in vascular development and physiology. Compelling evidence indicates that Notch signaling is vital for vascular morphogenesis including arterial and venous differentiation and endothelial tip and stalk cell specification during sprouting angiogenesis and also vessel maturation featured by mural cell differentiation and recruitment. Notch signaling is also required for vascular homeostasis in adults by keeping quiescent phalanx cells from re-entering cell cycle and by modulating the behavior of endothelial progenitor cells. We will summarize recent advances of Notch pathway in vascular biology with special emphasis on the underlying molecular mechanisms.

[Clinical and experimental study on effects of ji shen mixture for infantile acute glomerulonephritis]

33 cases of acute glomerulonephritis treated with Ji Shen Mixture (JSM) were studied with 31 cases treated with Western medical therapy (WM) for comparison and 34 healthy subjects as controls. The levels of lipo-peroxide (LPO), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), theromboxane B2 (TXB2), 6-keto-PGF1 alpha and TXB2/6-keto-PGF1 alpha ratio were examined before and after treatment. Compared with healthy controls, the levels of LPO, TXB2, TXB2/6-keto-PGF1 alpha of patients increased and that of GSH-Px, 6-keto-PGF1 alpha decreased significantly, whereas SOD activity had no significant difference. After treatment, the level of LPO reduced and GSH-Px activities raised significantly, but the effect of JSM group was better than that of WM group. It indicated that JSM was more effective in clearing the free radicals. The TXB2, TXB2/6-keto-PGF1 alpha dropped and 6-keto-PGF1 alpha elevated significantly after treatment, the effects of JSM were markedly better than those of WM. Furthermore, JSM was more potent in raising the clearing rate of hematuria and proteinuria.

Cytodiagnosis of bone tumors by fine needle aspiration

A retrospective study was undertaken of bone lesions examined by preoperative fine needle aspiration (FNA) cytology in our hospital during the ten-year period from 1970 to 1979. The 430 cytologically examined lesions were classified into three groups: inflammatory lesions, tumorlike lesions and tumors. A total of 54 patients had undergone surgery, with most of the lesions in those cases proven to be tumors or tumorlike by histologic study. Correlation between the histologic and FNA cytologic findings showed complete compatibility in 76% of the cases, partial compatibility in 13% and incompatibility in 11%. It is concluded that FNA biopsy is appropriate for identifying bone tumors and tumorlike lesions if sufficient numbers of tumor cells are obtained for morphologic examination. Although aspiration cytodiagnosis can be of considerable value in the recognition of certain bone lesions, it cannot replace formal tissue biopsy in the diagnosis of primary bone neoplasms. The morphology of several common bone tumors is described in detail and their differential diagnosis is discussed.