RESUMO
Acinetobacter baumannii is a critical biofilm-forming pathogen that has presented great challenges in the clinic due to multidrug resistance. Thus, new methods of intervention are needed to control biofilm-associated infections. In this study, among three tested Lactobacillus species, Lactobacillus rhamnosus showed significant antimaturation and antiadherence effects against A. baumannii biofilm. Lactic acid (LA) and acetic acid (AA) were the most effective antibiofilm biosurfactants (BSs) produced by L. rhamnosus. This antibiofilm phenomenon produced by LA and AA was due to the strong bactericidal effect, which worked from very early time points, as determined by colony enumeration and confocal laser scanning microscope. The cell destruction of A. baumannii appeared in both the cell envelope and cytoplasm. A discontinuous cell envelope, the leakage of cell contents, and the increased extracellular activity of ATPase demonstrated the disruption of the cell membrane by LA and AA. These effects also demonstrated the occurrence of protein lysis. In addition, bacterial DNA interacted with and was damaged by LA and AA, resulting in significantly reduced expression of biofilm and DNA repair genes. The results highlight the possibility and importance of using probiotics in clinical prevention. Probiotics can be utilized as novel biocides to block and decrease biofilm formation and microbial contamination in medical equipment and during the treatment of infections. IMPORTANCE A. baumannii biofilm is a significant virulence factor that causes the biofilm colonization of invasive illnesses. Rising bacterial resistance to synthetic antimicrobials has prompted researchers to look at natural alternatives, such as probiotics and their derivatives. In this study, L. rhamnosus and its BSs (LA and AA) demonstrated remarkable antibiofilm and antimicrobial characteristics, with a significant inhibitory effect on A. baumannii. These effects were achieved by several mechanisms, including the disruption of the cell envelope membrane, protein lysis, reduced expression of biofilm-related genes, and destruction of bacterial DNA. The results provide support for the possibility of using probiotics and their derivatives in the clinical prevention and therapy of A. baumannii infections.
RESUMO
Oncogenic BcrAbl kinase mimics preB cell receptor (preBCR) survival signals in BCRABL1positive Bcell acute lymphoblastic leukemia (BCRABL1+ BALL), driving Bcell progenitor malignant transformation; thus, defining a particularly unfavorable prognosis for patients. During Bcell development, preBCR differentiation signaling components terminate proliferative expansion and promote Bcell maturation. To study whether preBCR differentiation signaling components regulate the initiation and development of BCRABL1+ BALL, the tumor suppression mechanism of differentiationrelated signaling molecules in BCRABL1transformed proB cells were analyzed. The results demonstrated that BcrAbl kinase activated the PI3K/Akt pathway, promoting cell growth, and upregulated Aid expression, increasing genomic instability in proB cells. These findings suggest that BcrAbl kinase mediates proB cell malignant transformation. Furthermore, the present data revealed that BCRABL1 oncogenic stress triggered enhanced expression of Bcell differentiation components Bcell linker (Blnk) and forkhead box protein O1 (Foxo1) in BCRABL1 transformed proB cells. Using the CRISPR/Cas9mediated Blnk or Foxo1 knockout BCRABL1transformed proB cells, it was identified that, in BCRABL1transformed proB cells, Blnk and Foxo1 reduced BcrAbl kinase activity to induce cell cycle arrest and decrease genomic instability. In addition, Blnk suppressed the PI3K/Akt pathway to reduce Foxo1 phosphorylation and heighten the Foxo1 activity, indicating that, in BCRABL1transformed proB cells, Foxo1 participated in the regulation of BcrAbl kinase by Blnk. The present data highlighted the antitumor mechanisms of Blnk and Foxo1 in the regulation of BcrAbl kinase, and thus, may offer an alternative therapeutic strategy to BcrAbl kinase regulation in BCRABL1+ BALL.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteína Forkhead Box O1/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Linhagem Celular , Transformação Celular Neoplásica/patologia , Proteína Forkhead Box O1/genética , Proteínas de Fusão bcr-abl/genética , Técnicas de Inativação de Genes , Humanos , Camundongos , Camundongos Transgênicos , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genéticaRESUMO
In our previous studies, using a B cell vaccine (scFv-Her2), the targeting of tumor-associated antigen Her2 (human epidermal growth factor receptor-2) to B cells via the anti-CD19 single chain variable fragment (scFv) was shown to augment tumor-specific immunity, which enhanced tumor control in the prophylactic and therapeutic setting. However, the fusion protein displayed limited activity against established tumors, and local relapses often occurred following scFv-Her2 treatment, indicating that scFv-Her2-induced responses are inadequate to maintain anti-tumor immunity. In this study, targeting the IV region (D4) of the extracellular region of Her2 to B cells via CD19 molecules (scFv-Her2D4) was found to enhance IFN-γ-producing-CD8+ T cell infiltration in tumor tissues and reduced the number of tumor-infiltrating myeloid-derived suppressor cells (MDSCs). However, negative co-stimulatory molecules such as programmed cell death protein-1 (PD-1), CD160, and LAG-3 on T cells and programmed death protein ligand-1 (PD-L1) on tumor cells were upregulated in the tumor microenvironment after scFv-Her2D4 treatment. Further, anti-PD1 administration enhanced the efficacy of scFv-Her2D4 and anti-tumor immunity, as evidenced by the reversal of tumor-infiltrating CD8+ T cell exhaustion and the reduction of MDSCs and Treg cells, which suppress T cells and alter the tumor immune microenvironment. Moreover, combining this with anti-PD1 antibodies promoted complete tumor rejection. Our data provide evidence of a close interaction among tumor vaccines, T cells, and the PD-L1/PD-1 axis and establish a basis for the rational design of combination therapy with immune modulators and tumor vaccine therapy.
Assuntos
Antígenos CD19 , Linfócitos B , Vacinas Anticâncer , Receptor ErbB-2 , Proteínas Recombinantes de Fusão , Animais , Linfócitos B/imunologia , Vacinas Anticâncer/imunologia , Vacinas Anticâncer/farmacologia , Linhagem Celular Tumoral , Neoplasias do Colo/imunologia , Neoplasias do Colo/terapia , Feminino , Neoplasias Mamárias Experimentais/imunologia , Neoplasias Mamárias Experimentais/terapia , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Recombinantes de Fusão/imunologia , Proteínas Recombinantes de Fusão/farmacologiaRESUMO
Breakpoint cluster region (BCR)Abelson murine leukemia (ABL)1+ acute Blymphoblastic leukemia (BALL) is a disease associated with a dismal prognosis and a high incidence of central nervous system (CNS) metastasis. However, BCRABL1+ BALL with CNS infiltration has not been previously characterized, at least to the best of our knowledge. In the present study, a murine model of BCRABL1+ BALL with CNS metastasis was established using retroviral transduction. The vast majority of BCRABL1+ leukemic cells were found to be immature B cells with a variable proportion of proB and preB populations. The present results indicated that the BCRABL1+ Bleukemic cells expressed high levels integrin subunit alpha 6 (Itga6) and Lselectin adhesion molecules, and have an intrinsic ability to disseminate and accumulate in CNS tissues, predominantly in meninges. On the whole, these results provide an approach for addressing the mechanisms of BCRABL1+ BALL with CNS metastasis and may guide the development of novel therapeutic strategies.