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Abstract Cyclin-dependent kinase 9 (CDK9) is a crucial component of transcription and potential target for anti-cancer therapies, particularly for hematological malignancies. However, the precise mechanisms underlying the therapeutic effects of CDK9 inhibitors remain not fully understood. Here, we found that inhibiting CDK9 either pharmacologically or through gene downregulation, significantly reduced the levels of α-tubulin protein in a time- and dose-dependent manner. We further discovered that CDK9 inhibition led to increased susceptibility of α-tubulin to proteasomal degradation due to reduced acetylation at lysine 40 (K40), an important modification for microtubule stability. An acetylation-mimicking mutant of α-tubulin mitigated the anti-tumor effects of CDK9 inhibition. Mechanically, we identified that CDK9 inhibition downregulated the expression of ATAT1, the acetyltransferase responsible for α-tubulin acetylation, further compromising microtubule stability. We also conducted in vivo studies in a leukemic xenograft model, where AZD4573 treatment led to significant tumor regression, decreased ATAT1 expression, and α-tubulin degradation. Our study unravels a novel molecular mechanism by which CDK9 inhibition disrupts α-tubulin stability and provides valuable insights for exploring effective treatment regimens involving CDK9 inhibitors.

In this paper, the influence of decreasing Zr content (0.0110 wt%, 0.0044 wt%) on the microstructure, MnS inclusion characteristics, and mechanical properties of medium carbon ferrite-pearlite steel was studied. The results show that the volume fraction of intragranular ferrite (IGF) in steel increases with a reduction in Zr content. The ductility of the steel is reduced by 1.83%, the impact toughness is increased by 2.5 times, and the yield strength is almost unchanged. Compound MnS inclusions are the main inclusions that induce IGF formation. The proportion of heterogeneous nucleation of MnS inclusions using oxides as nucleation sites is increased, which is the main reason for the increase in the volume fraction of IGF. Furthermore, MnS inclusions change from type Ⅲ to type Ⅰ and Ⅱ, and their distribution is gradually uniform. Thermodynamic analysis reveals that the underlying cause for the morphological transformation of MnS inclusions is the rapid surge in the supersaturation of S element in molten steel. The presence of liquid-phase low-melting inclusions (MnS–Al2O3) promotes the formation of type Ⅰ MnS inclusions. The volume fraction and the dimension perpendicular to the fracture surface of the MnS inclusions are increased by at least 33% and 111%, while their aspect ratio is reduced by a maximum of up to 19%. The change in the volume fraction of MnS inclusions is the primary factor contributing to the decrease of tensile plasticity. The toughness of steel is mainly affected by the aspect ratio and the dimension perpendicular to the fracture surface of MnS inclusions.

The method used to strengthen copper matrix composites generally results in a significant decrease in ductility and electrical conductivity. In this work, multilayer graphene was grown on both sides of copper foil using chemical vapor deposition process and graphene/copper layered composites were prepared by stacking copper foils and hot rolling under vacuum. The microstructures, mechanical properties and electrical conductivity of hot rolled graphene/copper layered composites with different reduction amounts were investigated. Results showed that the grain size increased while the dislocation density did not change much with the reduction amounts from 30% to 50%. The size of graphene decreased and the spacing of graphene increased with the reduction amounts. When the reduction amounts increased from 30% to 50%, the tensile strength decreased from 223 MPa to 163 MPa, the elongation decreased from 45% to 31% and the electrical conductivity decreased from 101.52 %IACS to 89.73 %IACS. The optimized combination of properties was obtained when the hot rolled reduction amount was set as 30% because of the grain refining and the change in graphene size and spacing. Combining the analysis of microstructures and properties of the unreinforced copper matrix at 30% reduction amount, it can be concluded that the tensile strength of the composite increased from 179 MPa to 223 MPa, elongation increased from 38% to 45% and electrical conductivity increased from 98.02 %IACS to 101.52 %IACS. Long and distributed continuously graphene were beneficial to the improvement of strength, elongation and electrical conductivity by playing an obvious role in the load transfer strengthening mechanism, refining the grain size of the composites, and preventing the crack propagation.

Abstract NRAS mutations are most frequently observed in hematological malignancies and are also common in some solid tumors such as melanoma and colon cancer. Despite its pivotal role in oncogenesis, no effective therapies targeting NRAS has been developed. Targeting NRAS localization to the plasma membrane (PM) is a promising strategy for cancer therapy, as its signaling requires PM localization. However, the process governing NRAS translocation from the Golgi apparatus to the PM after lipid modification remains elusive. This study identifies GOLGA7 as a crucial factor controlling NRAS’ PM translocation, demonstrating that its depletion blocks NRAS, but not HRAS, KRAS4A and KRAS4B, translocating to PM. GOLGA7 is known to stabilize the palmitoyltransferase ZDHHC9 for NRAS and HRAS palmitoylation, but we found that GOLGA7 depletion does not affect NRAS’ palmitoylation level. Further studies show that loss of GOLGA7 disrupts NRAS anterograde trafficking, leading to its cis-Golgi accumulation. Remarkably, depleting GOLGA7 effectively inhibits cell proliferation in multiple NRAS-mutant cancer cell lines and attenuates NRASG12D-induced oncogenic transformation in vivo. These findings elucidate a specific intracellular trafficking route for NRAS under GOLGA7 regulation, highlighting GOLGA7 as a promising therapeutic target for NRAS-driven cancers.

Abstract Background The current standard of care for locally advanced gastric cancer (GC) involves neoadjuvant chemotherapy followed by radical surgery. Recently, neoadjuvant treatment for this condition has involved the exploration of immunotherapy plus chemotherapy as a potential approach. However, the efficacy remains uncertain. Methods A single‐arm, phase 2 study was conducted to evaluate the efficacy and tolerability of neoadjuvant camrelizumab combined with mFOLFOX6 and identify potential biomarkers of response through multi‐omics analysis in patients with resectable locally advanced GC. The primary endpoint was the pathological complete response (pCR) rate. Secondary endpoints included the R0 rate, near pCR rate, progression‐free survival (PFS), disease‐free survival (DFS), and overall survival (OS). Multi‐omics analysis was assessed by whole‐exome sequencing, transcriptome sequencing, and multiplex immunofluorescence (mIF) using biopsies pre‐ and post‐neoadjuvant therapy. Results This study involved 60 patients, of which 55 underwent gastrectomy. Among these, five (9.1%) attained a pathological complete response (pCR), and 11 (20.0%) reached near pCR. No unexpected treatment‐emergent adverse events or perioperative mortality were observed, and the regimen presented a manageable safety profile. Molecular changes identified through multi‐omics analysis correlated with treatment response, highlighting associations between HER2‐positive and CTNNB1 mutations with treatment sensitivity and a favourable prognosis. This finding was further supported by immune cell infiltration analysis and mIF. Expression data uncovered a risk model with four genes (RALYL, SCGN, CCKBR, NTS) linked to poor response. Additionally, post‐treatment infiltration of CD8+ T lymphocytes positively correlates with pathological response. Conclusion The findings suggest the combination of PD‐1‐inhibitor and mFOLFOX6 showed efficacy and acceptable toxicity for locally advanced GC. Extended follow‐up is required to determine the duration of the response. This study lays essential groundwork for developing precise neoadjuvant regimens.

Abstract FLT3 mutations are the most frequently identified genetic alterations in acute myeloid leukemia (AML) and are associated with poor prognosis. Multiple FLT3 inhibitors are in various stages of clinical evaluation. However, resistance to FLT3 inhibitors resulting from acquired point mutations in tyrosine kinase domain (TKD) have limited the sustained efficacy of treatments, and a “gatekeeper” mutation (F691L) is resistant to most available FLT3 inhibitors. Thus, new FLT3 inhibitors against both FLT3 internal tandem duplication (FLT3-ITD) and FLT3-TKD mutations (including F691L) are urgently sought. Herein, we identified KX2-391 as a dual FLT3 and tubulin inhibitor and investigated its efficacy and mechanisms in overcoming drug-resistant FLT3-ITD-TKD mutations in AML. KX2-391 exhibited potent growth inhibitory and apoptosis promoting effects on diverse AML cell lines harboring FLT3-ITD mutations and AC220-resistant mutations at the D835 and F691 residues in TKD and inhibited FLT3 phosphorylation and its downstream signaling targets. Orally administered KX2-391 significantly prolonged the survival of a murine leukemia model induced by FLT3-ITD-F691L. KX2-391 also significantly inhibited the growth of 4 primary AML cells expressing FLT3-ITD and 2 primary AML cells expressing FLT3-ITD-D835Y. Our preclinical data highlight KX2-391 as a promising FLT3 inhibitor for the treatment of AML patients harboring FLT3 mutations, especially refractory/relapsed patients with F691L and other FLT3-TKD mutations.

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis worldwide, with varied clinical and histopathological features between individuals, particularly across races. As an autoimmune disease, IgAN arises from consequences of increased circulating levels of galactose-deficient IgA1 and mesangial deposition of IgA-containing immune complexes, which are recognized as key events in the widely accepted “multi-hit” pathogenesis of IgAN. The emerging evidence further provides insights into the role of genes, environment, mucosal immunity and complement system. These developments are paralleled by the increasing availability of diagnostic tools, potential biomarkers and therapeutic agents. In this review, we summarize current evidence and outline novel findings in the prognosis, clinical trials and translational research from the updated perspectives of IgAN pathogenesis.

Abstract IRF8 is a key regulator of innate immunity receptor signaling and plays diverse functions in the development of hematopoietic cells. The effects of IRF8 on hematopoietic stem cells (HSCs) are still unknown. Here, it is demonstrated that IRF8 deficiency results in a decreased number of long‐term HSCs (LT‐HSCs) in mice. However, the repopulation capacity of individual HSCs is significantly increased. Transcriptomic analysis shows that IFN‐γ and IFN‐α signaling is downregulated in IRF8‐deficient HSCs, while their response to proinflammatory cytokines is unchanged ex vivo. Further tests show that Irf8−/− HSCs can not respond to CpG, an agonist of Toll‐like receptor 9 (TLR9) in mice, while long‐term CpG stimulation increases wild‐type HSC abundance and decreases their bone marrow colony‐forming capacity. Mechanistically, as the primary producer of proinflammatory cytokines in response to CpG stimulation, dendritic cells has a blocked TLR9 signaling due to developmental defect in Irf8−/− mice. Macrophages remain functionally intact but severely reduce in Irf8−/− mice. In NK cells, IRF8 directly regulates the expression of Tlr9 and its deficiency leads to no increased IFNγ production upon CpG stimulation. These results indicate that IRF8 regulates HSCs, at least in part, through controlling TLR9 signaling in diverse innate immune cells.

Hepatitis B virus (HBV) infection of hepatocytes begins by binding to its cellular receptor sodium taurocholate cotransporting polypeptide (NTCP), followed by the internalization of viral nucleocapsid into the cytoplasm. The viral relaxed circular (rc) DNA genome in nucleocapsid is transported into the nucleus and converted into covalently closed circular (ccc) DNA to serve as a viral persistence reservoir that is refractory to current antiviral therapies. Host DNA repair enzymes have been speculated to catalyze the conversion of rcDNA to cccDNA, however, the DNA polymerase(s) that fills the gap in the plus strand of rcDNA remains to be determined. Here we conducted targeted genetic screening in combination with chemical inhibition to identify the cellular DNA polymerase(s) responsible for cccDNA formation, and exploited recombinant HBV with capsid coding deficiency which infects HepG2-NTCP cells with similar efficiency of wild-type HBV to assure cccDNA synthesis is exclusively from de novo HBV infection. We found that DNA polymerase κ (POLK), a Y-family DNA polymerase with maximum activity in non-dividing cells, substantially contributes to cccDNA formation during de novo HBV infection. Depleting gene expression of POLK in HepG2-NTCP cells by either siRNA knockdown or CRISPR/Cas9 knockout inhibited the conversion of rcDNA into cccDNA, while the diminished cccDNA formation in, and hence the viral infection of, the knockout cells could be effectively rescued by ectopic expression of POLK. These studies revealed that POLK is a crucial host factor required for cccDNA formation during a de novo HBV infection and suggest that POLK may be a potential target for developing antivirals against HBV.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is a novel phlebovirus in the Bunyaviridae family. Most patients infected by SFTSV present with fever and thrombocytopenia, and up to 30% die due to multiple-organ dysfunction. The mechanisms by which SFTSV enters multiple cell types are unknown. SFTSV contains two species of envelope glycoproteins, Gn (44.2 kDa) and Gc (56 kDa), both of which are encoded by theMsegment and are cleaved from a precursor polypeptide (about 116 kDa) in the endoplasmic reticulum (ER). Gn fused with an immunoglobulin Fc tag at its C terminus (Gn-Fc) bound to multiple cells susceptible to the infection of SFTSV and blocked viral infection of human umbilical vein endothelial cells (HUVECs). Immunoprecipitation assays following mass spectrometry analysis showed that Gn binds to nonmuscle myosin heavy chain IIA (NMMHC-IIA), a cellular protein with surface expression in multiple cell types. Small interfering RNA (siRNA) knockdown of NMMHC-IIA, but not the closely related NMMHC-IIB or NMMHC-IIC, reduced SFTSV infection, and NMMHC-IIA specific antibody blocked infection by SFTSV but not other control viruses. Overexpression of NMMHC-IIA in HeLa cells, which show limited susceptivity to SFTSV, markedly enhanced SFTSV infection of the cells. These results show that NMMHC-IIA is critical for the cellular entry of SFTSV. As NMMHC-IIA is essential for the normal functions of platelets and human vascular endothelial cells, it is conceivable that NMMHC-IIA directly contributes to the pathogenesis of SFTSV and may be a useful target for antiviral interventions against the viral infection. [ABSTRACT FROM AUTHOR]