Synergistic effects of the KDM4C inhibitor SD70 and the menin inhibitor MI-503 against MLL::AF9-driven acute myeloid leukaemia.

MLL-rearranged (MLL-r) leukaemia is observed in approximately 10% of acute myeloid leukaemia (AML) and is associated with a relatively poor prognosis, highlighting the need for new treatment regimens. MLL fusion proteins produced by MLL rearrangements recruit KDM4C to mediate epigenetic reprogramming, which is required for the maintenance of MLL-r leukaemia. In this study, we used a combinatorial drug screen to selectively identify synergistic treatment partners for the KDM4C inhibitor SD70. The results showed that the drug combination of SD70 and MI-503, a potent menin-MLL inhibitor, induced synergistically enhanced apoptosis in MLL::AF9 leukaemia cells without affecting normal CD34+ cells. In vivo treatment with SD70 and MI-503 significantly prolonged survival in AML xenograft models. Differential gene expression analysis by RNA-seq following combined pharmacological inhibition of SD70 and MI-503 revealed changes in numerous genes, with MYC target genes being the most significantly downregulated. Taken together, these data provide preclinical evidence that the combination of SD70 and MI-503 is a potential dual-targeted therapy for MLL::AF9 AML.

Gadd45g insufficiency drives the pathogenesis of myeloproliferative neoplasms.

Despite the identification of driver mutations leading to the initiation of myeloproliferative neoplasms (MPNs), the molecular pathogenesis of MPNs remains incompletely understood. Here, we demonstrate that growth arrest and DNA damage inducible gamma (GADD45g) is expressed at significantly lower levels in patients with MPNs, and JAK2V617F mutation and histone deacetylation contribute to its reduced expression. Downregulation of GADD45g plays a tumor-promoting role in human MPN cells. Gadd45g insufficiency in the murine hematopoietic system alone leads to significantly enhanced growth and self-renewal capacity of myeloid-biased hematopoietic stem cells, and the development of phenotypes resembling MPNs. Mechanistically, the pathogenic role of GADD45g insufficiency is mediated through a cascade of activations of RAC2, PAK1 and PI3K-AKT signaling pathways. These data characterize GADD45g deficiency as a novel pathogenic factor in MPNs.

Twist family BHLH transcription factor 1 is required for the maintenance of leukemia stem cell in MLL-AF9+ acute myeloid leukemia.

Leukemia stem cells (LSC) are a rare population capable of limitless self-renewal and are responsible for the initiation, maintenance, and relapse of leukemia. Elucidation of the mechanisms underlying the regulation of LSC function could provide novel treatment strategies. Here, we show that TWIST1 is extremely highly expressed in the LSC of MLL-AF9+ acute myeloid leukemia (AML), and its upregulation is positively regulated by KDM4C in a H3K9me3 demethylation-dependent manner. We further demonstrate that TWIST1 is essential for the viability, dormancy, and self-renewal capacities of LSC, and that it promotes the initiation and maintenance of MLL-AF9-mediated AML. In addition, TWIST1 directly interacts and collaborates with HOXA9 in inducing AML in mice. Mechanistically, TWIST1 exerts its oncogenic function by activating the WNT5a/RAC1 axis. Collectively, our study uncovers a critical role of TWIST1 in LSC function and provides new mechanistic insights into the pathogenesis of MLL-AF9+ AML.

Characterization and the comprehensive expression analysis of tobacco valine-glutamine genes in response to trichomes development and stress tolerance.

Valine-glutamine genes (VQ) acted as transcription regulators and played the important roles in plant growth and development, and stress tolerance through interacting with transcription factors and other co-regulators. In this study, sixty-one VQ genes containing the FxxxVQxxTG motif were identified and updated in the Nicotiana tobacum genome. Phylogenetic analysis indicated that NtVQ genes were divided into seven groups and genes of each group had highly conserved exon-intron structure. Expression patterns analysis firstly showed that NtVQ genes expressed individually in different tobacco tissues including mixed-trichome (mT), glandular-trichome (gT), and nonglandular-trichome (nT), and the expression levels were also distinguishing in response to methyl jasmonate (MeJA), salicylic acid (SA), gibberellic acid (GA), ethylene (ETH), high salinity and PEG stresses. Besides, only NtVQ17 of its gene family was verified to have acquired autoactivating activity. This work will not only lead a foundation on revealing the functions of NtVQ genes in tobacco trichomes but also provided references to VQ genes related stress tolerance research in more crops.

[Construction and application of lentivirus overexpression vector with two labeling genes fused with CopGFP and PuroR].

Objective: To construct the lentivirus overexpression vector with two label genes fused with CopGFP and PuroR and to detect the emission of green fluorescence as well as resistance to puromycin in liver cancer cells infected with lentivirus packaged with the above vector. Methods: Firstly, two fragments containing copGFP and PuroR coding sequences were amplified from pCDH-CMV-MCS-copGFP and pLKO.1 respectively; secondly, the two amplified regions were fused with each other by recombinant PCR; thirdly, the fusion DNA fragment was cut and inserted into pCDH-CMV-MCS-copGFP vector, which was linearized with the same restriction endonuclease as used to digest fusion DNA fragment: BamH Ⅰ and Sal Ⅰ. The fusion region in the constructed vector was confirmed by DNA sequencing. The checked vector was co-transfected with package assistant plasmids, namely PLP1, PLP2 and VSVG into in 293T cells and the culture supernatant was subjected to centrifuge and infect liver cancer MHCC97H cells, which were then used to detect their resistance to puromycin (infected cells were treated with 1 mg/ml puromycin for 7 days after infection) and to observe green fluorescence emission in microscope. To determine its efficiency in expressing foreign target protein, the Sp1 coding region was inserted into the MCS sites of the vector, and Sp1 mRNA and protein expression levels were compared with the vehicle vector by RT-qPCR and Western blot. Results: The lentivirus overexpression vector with two label genes fused with CopGFP and PuroR was successfully constructed, and the liver cancer cells infected with lentivirus packaged with the vector expressing two labeling genes fused with CopGFP and PuroRshowed both emission of green fluorescence and resistance to puromycin simultaneously, while cells containing with the vector inserted with Sp1 coding region improved Sp1 mRNA level with 3.3 fold and protein level with 2.2 fold higher in comparison with cells containing the vehicle vector (P＜0.01). Conclusion: The fused label genes consisting of copGFP and PuroR are correctly cloned into the lentivirus vector and confer cells with the ability to emission of green fluorescence and resistance to puromycin, besides, the vector may promote the expression of the target gene with long coding sequence.

Antioxidant capacity of phenolic compounds separated from tea seed oil in vitro and in vivo.

Tea seed oil is rich in phenols with good antioxidant capacity. However, the antioxidant capacity evaluation of tea seed oil polyphenols is not deep enough, which mainly focusing on the evaluation of the chemical system. Thirty-nine phenols were tentatively identified by UPLC-ESI-MS/MS analysis, including flavonoids and phenolic acids. The antioxidant capacity of phenol extracts was investigated in vitro and in vivo. The chemical assays showed the extracts had good proton and electron transfer capabilities. The CAA assay indicated the IC50 of the extracts was 77.93 ± 4.80 µg/mL and cell antioxidant capacity of the extracts was 101.05 ± 6.70 µmol·QE/100 g of oil. The animal experiments suggested phenol extracts could significantly improve the organ index, reduce malondialdehyde content, and increase superoxide dismutase, glutathione peroxidase and total antioxidant capacity (p < 0.05). This study was contributed to the antioxidant capacity of phenol extracts of tea seed oil by comprehensive evaluation.

Antioxidant capacity and interaction of endogenous phenolic compounds from tea seed oil.

Endogenous phenols play a significant role in delaying oil rancidity. In this study, the profile of 22 endogenous phenols was determined from tea seed oil by UPLC-MS/MS, of which 15 phenols were identified for the first time. Then seven phenols with high content and strong antioxidant capacity were selected to investigate interaction using the DPPH· and Rancimat. It was found that the interaction of combinations was inconsistent in different media. Combined quercetin + esculetin, caffeoyl tartaric acid + esculetin, caffeoyl tartaric acid + gentisic acid and esculetin + gentisic acid showed synergistic antioxidant effects in oil and ethanol systems. Moreover, through the evaluation of the lipid oxidation process, combined esculetin + gentisic acid exhibited the greatest synergistic antioxidant effect. Notably, combined quercetin + esculetin had an inhibitory effect on the formation of volatile compounds. These findings may provide a basis for explaining the oxidation stability of tea seed oil.

GADD45g acts as a novel tumor suppressor, and its activation suggests new combination regimens for the treatment of AML.

Acute myeloid leukemia (AML) is an aggressive hematopoietic malignancy for which there is an unmet need for novel treatment strategies. Here, we characterize the growth arrest and DNA damage-inducible gene gamma (GADD45g) as a novel tumor suppressor in AML. We show that GADD45g is preferentially silenced in AML, especially in AML with FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) mutations and mixed-lineage leukemia (MLL)-rearrangements, and reduced expression of GADD45g is correlated with poor prognosis in patients with AML. Upregulation of GADD45g impairs homologous recombination DNA repair, leading to DNA damage accumulation, and dramatically induces apoptosis, differentiation, and growth arrest and increases sensitivity of AML cells to chemotherapeutic drugs, without affecting normal cells. In addition, GADD45g is epigenetically silenced by histone deacetylation in AML, and its expression is further downregulated by oncogenes FLT3-ITD and MLL-AF9 in patients carrying these genetic abnormalities. Combination of the histone deacetylase 1/2 inhibitor romidepsin with the FLT3 tyrosine kinase inhibitor AC220 or the bromodomain inhibitor JQ1 exerts synergistic antileukemic effects on FLT3-ITD+ and MLL-AF9+ AML, respectively, by dually activating GADD45g. These findings uncover hitherto unreported evidence for the selective antileukemic role of GADD45g and provide novel strategies for the treatment of FLT3-ITD+ and MLL-AF9+ AML.

Chiroptical Response of Aluminum Nanocrescents at Ultraviolet Wavelengths.

Manipulation of plasmon modes at ultraviolet wavelengths using engineered nanophotonic devices allows for the development of high-sensitivity chiroptical spectroscopy systems. We present here an experimental framework based on aluminum-based crescent-shaped nanostructures that exhibit a strong chiroptical response at ultraviolet wavelengths. Through utilization of higher-order plasmon modes in wavelength-scale nanostructures, we address the inherent fabrication challenges in scaling the response to higher frequencies. Additionally, the distinct far-field spectral response types are analyzed within a coupled-oscillator model framework. We find two competing chiroptical response types that contribute toward potential ambiguity in the interpretation of the circular dichroism spectra. The first, optical activity, originates from the interaction between hybridized eigenmodes, whereas the second manifests as a response superficially similar to optical activity but originating instead from differential near-field absorption modes. The study of the chiroptical response from nanoplasmonic devices presented here is expected to aid the development of next-generation chiroptical spectroscopy systems.

Expression patterns of endogenous avian retrovirus ALVE1 and its response to infection with exogenous avian tumour viruses.

Endogenous retroviruses (ERVs) are genomic elements that are present in a wide range of vertebrates and have been implicated in a variety of human diseases, including cancer. However, the characteristic expression patterns of ERVs, particularly in virus-induced tumours, is not fully clear. DNA methylation was analysed by bisulfite pyrosequencing, and gene expression was analysed by RT-qPCR. In this study, we first found that the endogenous avian retrovirus ALVE1 was highly expressed in some chicken tissues (including the heart, bursa, thymus, and spleen) at 2 days of age, but its expression was markedly decreased at 35 days of age. In contrast, the CpG methylation level of ALVE1 was significantly lower in heart and bursa at 2 days than at 35 days of age. Moreover, we found that the expression of ALVE1 was significantly inhibited in chicken embryo fibroblast cells (CEFs) and MSB1 cells infected with avian leukosis virus subgroup J (ALVJ) and reticuloendotheliosis virus (REV) at the early stages of infection. In contrast, the expression of the ALVE1 env gene was significantly induced in CEFs and MSB1 cells infected with Marek's disease virus (MDV). However, the methylation and expression levels of the ALVE1 long terminal repeat (LTR) did not show obvious alterations in response to viral infection. The present study revealed the expression patterns of ALVE1 in a variety of chicken organs and tissues and in chicken cells in response to avian tumour virus infection. These findings may be of significance for understanding the role and function of ERVs that are present in the host genome.

Expression of the env gene from the avian endogenous retrovirus ALVE and regulation by miR-155.

Endogenous retroviruses (ERVs) are important retroelements that reside in host genomes. However, ERV expression patterns and regulatory mechanisms are poorly understood. In this study, chicken embryo fibroblasts (CEFs) and MSB1 cells infected with Marek's disease virus (MDV) exhibited significantly increased expression of env from the endogenous retrovirus ALVE. In contrast, env expression was significantly lower in CEF and MSB1 cells infected with exogenous avian leukosis virus J (ALVJ) at the early infection stage. Furthermore, env was found to be ubiquitously expressed in various chicken tissues, with high expression in certain tissues at 2 days of age and low levels in most tissues, including immune organs (thymus, spleen and bursa) as well as the brain and heart, at 35 days of age. Sequence analysis revealed miR-155 target sites in env transcripts, which was verified using a firefly luciferase reporter assay, and treatment with miR-155 agomir significantly decreased levels of env transcripts in MSB1 and CEF cells. Together, these findings suggest that the env gene from the endogenous retrovirus ALVE is regulated by miR-155.

Generation of broadband radially polarized terahertz radiation directly on a cylindrical metal wire.

We demonstrate the ability to directly generate broadband THz surface plasmons via optical rectification on a cylindrical metal wire. This is accomplished by milling a single circumferential groove into the wire and overcoating it with a poled polymer that exhibits a bulk second order susceptibility. An attractive feature of this approach is the potential to generate THz pulses that are limited in duration only by the duration of the optical pump pulse. While a photoconductive detector is used in the present demonstration, we discuss further refinements to the system that should allow for significant enhancement of the nonlinear optical conversion efficiency and detection bandwidth.