Minute virus of canines (MVC) is an autonomous parvovirus in the genusBocaparvovirus. It has a single promoter that generates a single pre-mRNA processed via alternative splicing and alternative polyadenylation to produce at least 8 mRNA transcripts. MVC contains two polyadenylation sites, one at the right-hand end of the genome, (pA)d, and another complex site, (pA)p, within the capsid-coding region. During viral infection, the mRNAs must extend through (pA)p and undergo additional splicing of the immediately upstream 3D⁄3A intron to access the capsid gene. MVC NP1 is a 22-kDa nuclear phosphoprotein unique to the genus Bocaparvovirus of the Parvovirinae which we have shown governs suppression of (pA)p independently of viral genome replication. We show here that in addition to suppression of (pA)p, NP1 is also required for the excision of the MVC 3D⁄3A intron, independently of its effect on alternative polyadenylation. Mutations of the arginine⁄serine (SR) di-repeats within the intrinsically disordered amino terminus of NP1 are required for splicing of the capsid transcript but not suppression of polyadenylation at (pA)p. 3=-end processing of MVC mRNAs at (pA)p is critical for viral genome replication and the optimal expression of NP1 and NS1. Thus, a finely tuned balance between (pA)p suppression and usage is necessary for efficient virus replication. NP1 is the first parvovirus protein implicated in RNA processing. Its characterization reveals another way that parvoviruses govern access to their capsid protein genes, namely, at the RNA level, by regulating the essential splicing of an intron and the suppression of an internal polyadenylation site. IMPORTANCEThe Parvovirinae are small nonenveloped icosahedral viruses that are important pathogens in many animal species, including humans. Although parvoviruses have only subtle early-to-late expression shifts, they all regulate access to their capsid genes. Minute virus of canines (MVC) is an autonomous parvovirus in the genusBocaparvovirus. It has a single promoter generating a single pre-mRNA which is processed via alternative splicing and alternative polyadenylation to generate at least 8 mRNA transcripts. MVC contains two polyadenylation sites, one at the right-hand end of the genome, (pA)d, and another, (pA)p, within the capsid-coding region. It had not been clear how the potent internal polyadenylation motif is suppressed to allow processing, export, and accumulation of the spliced capsid protein-encoding mRNAs. We show here that MVC NP1, the first parvovirus protein to be implicated in RNA processing, governs access to the MVC capsid gene by facilitating splicing and suppressing internal polyadenylation of MVC pre-mRNAs. M inute virus of canines (MVC) is an autonomous parvovirus in the genusBocaparvovirus. Infection in young dogs can result in neonatal mortality (1) and respiratory and gastrointestinal distress (2) and can cause infertility and stillbirths in adult pregnant female dogs (3). The parvovirus genus Bocaparvovirus has 12 currently known...
Human parvovirus B19 (B19V) is the causative agent of erythema infectiosum in humans. B19 infection also causes severe disease manifestations, such as chronic anemia in immunocompromised patients, aplastic crisis in patients with a high turnover rate of red blood cells, and hydrops fetalis in pregnant women. Although a secreted phospholipase A2 (PLA2) motif has been identified in the unique region of the B19V minor capsid protein VP1(VP1u), the determinants for its enzyme activity and its influences on host cells are not well understood. The purpose of this study was to investigate the contribution of the PLA2 motif and other regions of the VP1u to the PLA2 activity, to determine the cellular localization of the VP1u protein, and to examine the effects of VP1u on cellular cytokines. We found that in addition to the critical conserved and non-conserved amino acids within the VP1u PLA2 motif, amino acid residues outside the VP1u PLA2 motif are also important for the PLA2 activity. VP1u and various mutants all revealed a nucleo-cytoplasmic distribution. UT7-Epo cells treated with prokaryotic expressed VP1u or mutant proteins with PLA2 activity released a large amount of free fatty acid (FFA), and the cell morphological change occurred dramatically. However, neither free fatty acid nor cell morphology change occurred for cells treated with the mutants without PLA2 activity. The wild type and the VP1u mutants with the PLA2 activity also activated TNF-α promoter and upregulated the transcription activity of NF-κB in transfected cells. In addition, we found that the amino acids outside the PLA2 domain are critical for the viral PLA2 activity, and that these tested VP1u mutants did not affect the localization of the VP1u protein.
Two investigators independently reviewed the literatures. Before using the RevMan 5.3 software for a meta-analysis, date were extracted and the risk of bias with the include studies were assessed.Results: A total of 64 RCTs involving 3685 patients were included. Compared with placebo combined with endocrine therapy, CDK4/6 inhibitors combined with endocrine therapy could improve the median progression free survival rate (hazard ratio 0.54, 95% confidence interval (CI):0.50-0.60, P<0.00001).In terms of adverse reactions, CDK4/6 inhibitors combined with endocrine therapy had higher rates of neutropenia, leukopenia, thrombocytopenia, anemia, fatigue, diarrhea, febrile neutropenia, nausea and increased alanine aminotransferase (ALT).Discussion: CDK4/6 inhibitors have strong specification in the treatment of ABC because of their role in regulating the cell cycle. Although CDK4/6I combined with endocrine therapy can improve the effective rate and median PFS of patients with HR+/HER2-ABC, this treatment regimen increases the incidence of adverse reactions such as neutropenia, leukopenia, thrombocytopenia, anemia, fatigue, diarrhea, febrile neutropenia, nausea and increased ALT. Further research into improving the survival rate while reducing or even avoiding the side effects of CDK4/6Isis needed for better clinical management of BC.
Background The application of combination therapy for cancer treatment is limited due to poor tumor-specific drug delivery and the abscopal effect. Methods Here, PD-L1- and CD44-responsive multifunctional nanoparticles were developed using a polymer complex of polyethyleneimine and oleic acid (PEI-OA) and loaded with two chemotherapeutic drugs (paclitaxel and chloroquine), an antigen (ovalbumin), an immunopotentiator (CpG), and an immune checkpoint inhibitor (anti-PD-L1 antibody). Results PEI-OA greatly improved the drug loading capacity and encapsulation efficiency of the nanoplatform, while the anti-PD-L1 antibody significantly increased its cellular uptake compared to other treatment formulations. Pharmacodynamic experiments confirmed that the anti-PD-L1 antibody can strongly inhibit primary breast cancer and increase levels of CD4+ and CD8+ T cell at the tumor site. In addition, chloroquine reversed the “immune-cold” environment and improved the anti-tumor effect of both chemotherapeutics and immune checkpoint inhibitors, while it induced strong immune memory and prevented lung metastasis. Conclusions Our strategy serves as a promising approach to the rational design of nanodelivery systems for simultaneous active targeting, autophagy inhibition, and chemotherapy that can be combined with immune-checkpoint inhibitors for enhanced breast cancer treatment.
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