RESUMO
This study explores the critical role of inhibitors targeting the mammalian target of rapamycin (mTOR) signaling pathway in breast cancer research and treatment. The mTOR pathway, a central regulator of cellular processes, has been identified as a crucial factor in the development and progression of breast cancer. The essay explains the complex molecular mechanisms through which mTOR inhibitors, such as rapamycin and its analogs, exert their anticancer effects. These inhibitors can stop cell growth, proliferation, and survival in breast cancer cells by blocking critical signaling pathways within the mTOR pathway. Furthermore, the essay discusses the implications of using mTOR inhibitors as a comprehensive therapeutic strategy. It emphasizes the potential benefits of combining mTOR inhibitors with other treatment approaches to enhance the effectiveness of breast cancer treatment. The evolving landscape of breast cancer research underscores the significance of mTOR as a therapeutic target and highlights ongoing efforts to improve and optimize mTOR inhibitors for clinical use. In conclusion, the essay asserts that inhibitors of the mTOR signaling pathway offer a promising approach in the fight against breast cancer. These inhibitors provide a focused and effective intervention targeting specific dysregulations within the mTOR pathway. As research advances, the integration of mTOR inhibitors into customized combination therapies holds excellent potential for shaping a more effective and personalized approach to breast cancer treatment, ultimately leading to improved outcomes for individuals affected by this complex and diverse disease.
RESUMO
The optimal duration of treatment with nucleos(t)ide analogues (NAs) for patients with HBeAg-negative chronic hepatitis B (CHB) is unknown. The aim of this study was to identify an immune signature associated with off-treatment remission to NA therapy. We performed microarray analysis of peripheral blood mononuclear cell (PBMCs) from six patients with chronic hepatitis B who stopped NA therapy (three with off-treatment remission, three with relapse) and five patients with chronic HBV infection (previously termed 'inactive carriers') served as controls. Results were validated using qRT-PCR on a second group of 21 individuals (17 patients who stopped treatment and four controls). PBMCs from 38 patients on long-term NA treatment were analysed for potential to stop treatment. Microarray analysis indicated that patients with off-treatment remission segregated as a distinct out-group. Twenty-one genes were selected for subsequent validation. Ten of these were expressed at significantly lower levels in the patients with off-treatment remission compared to the patients with relapse and predicted remission with AUC of 0.78-0.92. IFNγ, IL-8, FASLG and CCL4 were the most significant by logistic regression. Twelve (31.6%) of 38 patients on long-term NA therapy had expression levels of all these four genes below cut-off values and hence were candidates for stopping treatment. Our data suggest that patients with HBeAg-negative CHB who remain in off-treatment remission 3 years after NA cessation have a distinct immune signature and that PBMC RNA levels of IFNγ, IL-8, FASLG and CCL4 may serve as potential biomarkers for stopping NA therapy.
Assuntos
Antivirais/uso terapêutico , Antígenos E da Hepatite B/sangue , Hepatite B Crônica/imunologia , Nucleosídeos/uso terapêutico , Adulto , Idoso , Biomarcadores/sangue , Estudos Transversais , Feminino , Expressão Gênica , Genoma Humano , Vírus da Hepatite B/imunologia , Hepatite B Crônica/sangue , Hepatite B Crônica/tratamento farmacológico , Humanos , Leucócitos Mononucleares/imunologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Recidiva , Indução de Remissão , Análise Serial de Tecidos , Carga ViralRESUMO
The killer cell immunoglobulin-like receptor (KIR) KIR2DS2 induces natural killer (NK) cell activation upon ligation and in genetic studies is associated with protection against certain cancers and viral infections. One of the difficulties in understanding KIR2DS2 has been that ligands have been hard to define. In part, this is because the high sequence homology between KIR2DS2 and KIR2DL3/KIR2DL2 has made it difficult to make antibodies that specifically detect NK cells expressing KIR2DS2. Using transfected NK cell line (NKL) cells and primary human samples, we report the identification of a novel antibody combination which allows identification of NK cells with relatively high expression of KIR2DS2. This separation is sufficient to examine primary human NK cell activation in response to KIR2DS2 specific ligands.
Assuntos
Anticorpos/metabolismo , Imunofenotipagem/métodos , Células Matadoras Naturais/metabolismo , Neoplasias/imunologia , Receptores KIR/genética , Viroses/imunologia , Separação Celular , Células Cultivadas , Citometria de Fluxo , Heterozigoto , Humanos , Vigilância Imunológica , Ativação Linfocitária , Receptores KIR/imunologia , Receptores KIR/metabolismo , Receptores KIR2DL2/genética , Receptores KIR2DL2/imunologia , Receptores KIR2DL2/metabolismo , Receptores KIR2DL3/genética , Receptores KIR2DL3/imunologia , Receptores KIR2DL3/metabolismoRESUMO
Killer cell immunoglobulin-like receptors (KIRs) are rapidly evolving species-specific natural killer (NK) cell receptors associated with protection against multiple different human viral infections. We report that the activating receptor KIR2DS2 directly recognizes viral peptides derived from conserved regions of flaviviral superfamily 2 RNA helicases in the context of major histocompatibility complex class I. We started by documenting that peptide LNPSVAATL from the hepatitis C virus (HCV) helicase binds HLA-C*0102, leading to NK cell activation through engagement of KIR2DS2. Although this region is highly conserved across HCV isolates, the sequence is not present in other flaviviral helicases. Embarking on a search for a conserved target of KIR2DS2, we show that HLA-C*0102 presents a different highly conserved peptide from the helicase motif 1b region of related flaviviruses, including dengue, Zika, yellow fever, and Japanese encephalitis viruses, to KIR2DS2. In contrast to LNPSVAATL from HCV, these flaviviral peptides all contain an "MCHAT" motif, which is present in 61 of 63 flaviviruses. Despite the difference in the peptide sequences, we show that KIR2DS2 recognizes endogenously presented helicase peptides and that KIR2DS2 is sufficient to inhibit HCV and dengue virus replication in the context of HLA-C*0102. Targeting short, but highly conserved, viral peptides provide nonrearranging innate immune receptors with an efficient mechanism to recognize multiple, highly variable, pathogenic RNA viruses.
RESUMO
Productive engagement of MHC class I by inhibitory NK cell receptors depends on the peptide bound by the MHC class I molecule. Peptide:MHC complexes that bind weakly to killer cell Ig-like receptors (KIRs) can antagonize the inhibition mediated by high-affinity peptide:MHC complexes and cause NK cell activation. We show that low-affinity peptide:MHC complexes stall inhibitory signaling at the step of Src homology protein tyrosine phosphatase 1 recruitment and do not go on to form the KIR microclusters induced by high-affinity peptide:MHC, which are associated with Vav dephosphorylation and downstream signaling. Furthermore, the low-affinity peptide:MHC complexes prevented the formation of KIR microclusters by high-affinity peptide:MHC. Thus, peptide antagonism of NK cells is an active phenomenon of inhibitory synapse disruption.