No abstract

The t(8;21)(q22;q22) translocation is one of the most common genetic abnormalities in acute myeloid leukemia (AML), identified in 15% of all cases of AML, including 40-50% of FAB M2 subtype and rare cases of M0, M1 and M4 subtypes. The most commonly known AML1-ETO fusion protein (full-length AML1-ETO) from this translocation has 752 amino acids and contains the N-terminal portion of RUNX1 (also known as AML1, CBFalpha2 or PEBP2alphaB), including its DNA binding domain, and almost the entire RUNX1T1 (also known as MTG8 or ETO) protein. Although alterations of gene expression and hematopoietic cell proliferation have been reported in the presence of AML1-ETO, its expression does not lead to the development of leukemia. Here, we report the identification of a previously unknown alternatively spliced isoform of the AML1-ETO transcript, AML1-ETO9a, that includes an extra exon, exon 9a, of the ETO gene. AML1-ETO9a encodes a C-terminally truncated AML1-ETO protein of 575 amino acids. Expression of AML1-ETO9a leads to rapid development of leukemia in a mouse retroviral transduction-transplantation model. More importantly, coexpression of AML1-ETO and AML1-ETO9a results in the substantially earlier onset of AML and blocks myeloid cell differentiation at a more immature stage. These results indicate that fusion proteins from alternatively spliced isoforms of a chromosomal translocation may work together to induce cancer development.

BackgroundCisplatin resistance is a major challenge for advanced head and neck cancer (HNC). Understanding the underlying mechanisms and developing effective strategies against cisplatin resistance are highly desired in the clinic. However, how tumor stroma modulates HNC growth and chemoresistance is unclear.ResultsWe show that cancer-associated fibroblasts (CAFs) are intrinsically resistant to cisplatin and have an active role in regulating HNC cell survival and proliferation by delivering functional miR-196a from CAFs to tumor cells via exosomes. Exosomal miR-196a then binds novel targets, CDKN1B and ING5, to endow HNC cells with cisplatin resistance. Exosome or exosomal miR-196a depletion from CAFs functionally restored HNC cisplatin sensitivity. Importantly, we found that miR-196a packaging into CAF-derived exosomes might be mediated by heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1). Moreover, we also found that high levels of plasma exosomal miR-196a are clinically correlated with poor overall survival and chemoresistance.ConclusionsThe present study finds that CAF-derived exosomal miR-196a confers cisplatin resistance in HNC by targeting CDKN1B and ING5, indicating miR-196a may serve as a promising predictor of and potential therapeutic target for cisplatin resistance in HNC.Electronic supplementary materialThe online version of this article (10.1186/s13059-018-1604-0) contains supplementary material, which is available to authorized users.

(Table 1). Definitive quantitative assays include calibrators fit to a regression model to calculate absolute values and reference standards that are well characterized and fully representative of the endogenous measurand. Definitive quantitative assays can be both accurate and precise. Relative quantitative assays utilize responseconcentration calibration, however in this scenario the reference standards are not fully characterized or truly representative of the endogenous measurand. As such, imprecision can be demonstrated for a relative quantitative method, but accuracy can only be estimated. With quasi-quantitative assays there is a relationship between the response and the measurand but calibration standards are not used. Thus, quasi-quantitative methods can be validated for imprecision, but not accuracy. Qualitative methods generate categorical data. Flow cytometric methods largely fall in the two latter categories and are essentially therefore quasi-quantitative or qualitative.Multi-color flow cytometry is a unique technology, which enables the analysis of heterogeneous cellular systems and provides multiparametric information at a cellby-cell level. The strength of flow cytometry lies not only in the ability to simultaneously measure multiple parameters, but also in the flexibility to report them in different ways. The appropriate data output depends on the biology of the system being investigated, the analytical or scientific question being asked, and the intended use of the results. A wide variety of data outputs can be reported usually expressed in terms of several characteristics of cells, or cell subsets, in the sample tested for example, percentage of positive events, absolute counts, median fluorescence intensity, quantitative antigen expression levels, ratiometric indices, markers coexpression, or relative nucleic acid content.

ISG15 is one of the most strongly induced genes upon viral infection, type I interferon (IFN) stimulation, and lipopolysaccharide (LPS) stimulation. Here we report that mice lacking UBP43, a protease that removes ISG15 from ISGylated proteins, are hypersensitive to type I IFN. Most importantly, in UBP43-deficient cells, IFN-β induces a prolonged Stat1 tyrosine phosphorylation, DNA binding, and IFN-mediated gene activation. Furthermore, restoration of ISG15 conjugation in protein ISGylation-defective K562 cells increases IFN-stimulated promoter activity. These findings identify UBP43 as a novel negative regulator of IFN signaling and suggest the involvement of protein ISGylation in the regulation of the JAK-STAT pathway.

Innate immune responses provide the host with an early protection barrier against infectious agents, including viruses, and help shape the nature and quality of the subsequent adaptive immune responses of the host. Expression of ISG15 (UCRP), a ubiquitin-like protein, and protein ISGylation are highly increased upon viral infection. We have identified UBP43 (USP18) as an ISG15 deconjugating protease. Protein ISGylation is enhanced in cells deficient in UBP43 (ref. 6). Here we have examined the role of UBP43, encoded by the gene Usp18, in innate immunity to virus infection. Usp18(-/-) mice were resistant to the fatal lymphocytic choriomeningitis and myeloencephalitis that developed in wild-type mice after intracerebral inoculation with lymphocytic choriomeningitis virus (LCMV) or vesicular stomatitis virus (VSV), respectively. Survival of Usp18(-/-) mice after intracerebral LCMV infection correlated with a severe inhibition of LCMV RNA replication and antigen expression in the brain and increased levels of protein ISGylation. Consistent with these findings, mouse embryonic fibroblasts (MEF) and bone marrow-derived macrophages from Usp18(-/-) mice showed restricted LCMV replication. Moreover, MEF from Usp18(-/-) mice showed enhanced interferon-mediated resistance to the cytopathic effect caused by VSV and Sindbis virus (SNV). This report provides the first direct evidence that the ISG15 protease UBP43 and possibly protein ISGylation have a role in innate immunity against viral infection.

IntroductionThe Isodon plant, Rabdosia rubescens (RR), and its extracts, were shown in China to be able to suppress disease progress, reduce tumor burden, alleviate syndrome, and prolong survival in patients with esophageal, gastric carcinoma or liver cancer. [1][2][3][4][5] Of interest, other Isodon plants including Isodon japonicus Hara (IJ) and I trichocarpus (IT) were also applied as home remedies for similar disorders in Japan and Korea. 6 Oridonin ( Figure 1A), a bitter tetracycline diterpenoid compound, was isolated from RR, IJ, and IT separately, 7,8 suggesting oridonin should be an essential antitumor component of Isodon plants. Studies showed that oridonin induced apoptosis in a variety of cancer cells including those from prostate, breast, non-small cell lung cancers, acute leukemia (NB4, HL-60 cells), glioblastoma multiforme, and human melanoma cells. [9][10][11][12] Oridonin could also increase lifespan of mice bearing Ehrlich ascites or P388 lymphocytic leukemia. 13,14 However, though studies showed that caspase-3 (casp-3), casp-8, P53, Bcl-2/Bax, cytochrome c (cyt C), 10,15,16 and nuclear factor kappa B (NFB) 17 were involved in apoptosis induced by oridonin, mechanisms underlying the antitumor activity of oridonin remain largely unknown, and whether oridonin can find clinical application still needs more investigation.Genetic abnormalities have been shown to play a key role in leukemogenesis, 18 and treatment strategies interfering with oncoproteins involved in leukemia pathogenesis have been reported to have high therapeutic efficacy with low adverse effects. The BCR-ABL-targeting STI-571, in the treatment of chronic myeloid leukemia (CML), 19 and the PML-RAR␣-targeting agents all-trans retinoic acid (ATRA) and arsenic trioxide (ATO), in taming acute promyelocytic leukemia (APL), 20,21 can serve as paradigms. Hence molecular target-based therapies should be developed for leukemias with poor prognosis. The AML1-ETO (AE) fusion gene is the result of translocation t(8;21)(q22;q22), which is seen in 40% to 80% of M2-type acute myeloid leukemia (AML M2) and 12% to 20% of all cases of AML. 22,23 The AE fusion protein recruits the nuclear receptor corepressor (NCoR)-mammalian Sin3 (mSin3)-histone deacetylase (HDAC) complex, 24,25 inhibits transcription of AML1 target genes 22,24 including interleukin-3 (IL3), 26 activates transcription of apoptotic antagonist Bcl-2, 27 up-regulates protein tyrosine kinase C-KIT, 28 induces the expression of granulocyte colony-stimulating factor receptor (G-CSFR) as well as myeloperoxidase (MPO), 29 and blocks transactivation of the GM-CSF promoter. 30 The AE oncoprotein enhances self-renewal of hematopoietic stem/progenitor cells, blocks hematopoietic differentiation, disturbs normal cell proliferation, 31 and immortalizes murine hematopoietic progenitors. 32,33 Although reports suggest that additional mutations are required to cooperate with AE to cause murine The online version of this article contains a data supplement.The publication costs of this article were defr...

Type I interferons (IFNs) are multifunctional cytokines that regulate immune responses and cellular functions but also can have detrimental effects on human health. A tight regulatory network therefore controls IFN signaling, which in turn interferes with medical interventions. The JAK-STAT signaling pathway transmits the IFN extracellular signal to the nucleus for alterations of gene expression. STAT2 is a well-known essential and specific positive effector of type I IFN signaling. Here, we report that STAT2 is also a previously unrecognized crucial component of the USP18-mediated negative feedback control in both, human and murine cells. We found that STAT2 recruits USP18 to the type I IFN receptor subunit IFNAR2 via its constitutive membrane-distal STAT2 binding site. This mechanistic coupling of effector and negative feedback functions of STAT2 provides novel strategies in treatment of IFN signaling related human diseases.