Toll-like receptor 4 signaling pathway is correlated with pathophysiological characteristics of AML patients and its inhibition using TAK-242 suppresses AML cell proliferation

Identification and characterization of a TLR4 homologue in Eriocheir sinensis based on structure analysis

Toll-like receptor 4 (TLR4) plays an essential role in the activation of innate immunity by recognizing diverse pathogenic components of bacteria. Six Tolls were found in Eriocheir sinensis but have not yet been identified as mammalian TLR4 homolog. For this purpose, we predicted three-dimensional (3D) structures of EsTolls (EsToll1-6) with AlphaFold2. 3D structure of LRRs and TIR most had high accuracy (pLDDT >70). By structure analysis, 3D structures of EsToll6 had a high overlap with HsTLR4. Moreover, we also predicted potential 11 hydrogen bonds and 3 salt bridges in the 3D structure of EsToll6-EsML1 complex. 18 hydrogen bonds and 7 salt bridges were predicted in EsToll6-EsML2 complex. Co-immunoprecipitation assay showed that EsToll6 could interact with EsML1 and EsML2, respectively. Importantly, TAK242 (a mammalian TLR4-specific inhibitor) could inhibit the generation of ROS stimulated by lipopolysaccharides (LPS) in EsToll6-EsML2-overexpression Hela cells. Collectively, these results implied that EsToll6 was a mammalian TLR4 homolog and provided a new insight for researching mammalian homologs in invertebrates.

Anti-cancer effects of ginsenoside CK on acute myeloid leukemia in vitro and in vivo

Objectives

Acute myeloid leukemia (AML) is a malignant disease characterized by clonal proliferation of myeloid cells, and its treatment continues to be a challenge due to high morbidity and mortality. Ginsenoside compound K, a major active metabolite of the protopanaxadiol-type ginsenosides, exhibits biological activities in various cancer cells and animal models. Here, we investigated the role of CK in anticancer potential in AML both in vitro and in vivo.

Materials and methods

To investigate the inhibitory effects of CK in AML cells, in vitro experiments, including cell viability assays, colony forming assays, and cell cycle and apoptosis assays were performed. AML animal experiment was established and quantitative analysis of lung tumor growth nodules and spleen weight and H&E staining were carried out to further determine the effects of CK on AML. In addition, the potential key genes induced and influenced by CK during treatment was identification by RNA-seq and qRT-PCR.

Results

CK suppressed AML cell activity and induced apoptosis and G1 cell cycle arrest based on the experiment results. Moreover, significantly down-regulated expression genes of BCL2, KIT, DNMT3A, MYC and CSF-1 and up-regulated expression gene of TET2 in CK treatment AML cells were discovered.

Conclusion

Our results demonstrated that CK could be used as an anti-AML drug with significant therapeutic efficacy and good biosafety.

RAB27B inhibits proliferation and promotes apoptosis of leukemic cells via 3-Hydroxy butyrate dehydrogenase 2 (BDH2)

RAB27B is a member of Ras-like small GTPases that plays a role in endocytosis, exocytosis, and vesicle trafficking. We made an attempt to study the impacts of RAB27B on the proliferation and apoptosis of acute myeloid leukemia (AML) cells. The silencing of RAB27B was induced by siRNA for the detection of proliferation, cell cycle, and apoptosis, respectively by Cell Counting Kit-8 (CCK8), flow cytometry, and TUNEL. Related markers were also evaluated by Western blot analysis. The interaction between RAB27B and BDH2 was predicted by bioinformatics analysis and determined by immunoprecipitation. The gain of function of BDH2 was also detected by these functional assays. RAB27B exhibited high levels in AML cells, and RAB27B silencing led to reduced proliferation, increased cell cycle arrest and apoptosis levels. Then, the interaction between RAB27B and BDH2 was confirmed. Moreover, the effects of RAB27B inhibition on the proliferation, cell cycle arrest, and cell apoptosis were abolished after BDH2 overexpression. RAB27B inhibits proliferation and promotes apoptosis of leukemic cells by interacting with BDH2. Targeting RAB27B might be an effective method for the treatment of AML.

Toll-like Receptor 4, Osteoblasts and Leukemogenesis; the Lesson from Acute Myeloid Leukemia

Toll-like receptor 4 (TLR4) is a pattern-recognizing receptor that can bind exogenous and endogenous ligands. It is expressed by acute myeloid leukemia (AML) cells, several bone marrow stromal cells, and nonleukemic cells involved in inflammation. TLR4 can bind a wide range of endogenous ligands that are present in the bone marrow microenvironment. Furthermore, the TLR4-expressing nonleukemic bone marrow cells include various mesenchymal cells, endothelial cells, differentiated myeloid cells, and inflammatory/immunocompetent cells. Osteoblasts are important stem cell supporting cells localized to the stem cell niches, and they support the proliferation and survival of primary AML cells. These supporting effects are mediated by the bidirectional crosstalk between AML cells and supportive osteoblasts through the local cytokine network. Finally, TLR4 is also important for the defense against complicating infections in neutropenic patients, and it seems to be involved in the regulation of inflammatory and immunological reactions in patients treated with allogeneic stem cell transplantation. Thus, TLR4 has direct effects on primary AML cells, and it has indirect effects on the leukemic cells through modulation of their supporting neighboring bone marrow stromal cells (i.e., modulation of stem cell niches, regulation of angiogenesis). Furthermore, in allotransplant recipients TLR4 can modulate inflammatory and potentially antileukemic immune reactivity. The use of TLR4 targeting as an antileukemic treatment will therefore depend both on the biology of the AML cells, the biological context of the AML cells, aging effects reflected both in the AML and the stromal cells and the additional antileukemic treatment combined with HSP90 inhibition.

Insights into Modern Therapeutic Approaches in Pediatric Acute Leukemias

Pediatric cancers predominantly constitute lymphomas and leukemias. Recently, our knowledge and awareness about genetic diversities, and their consequences in these diseases, have greatly expanded. Modern solutions are focused on mobilizing and impacting a patient’s immune system. Strategies to stimulate the immune system, to prime an antitumor response, are of intense interest. Amid those types of therapies are chimeric antigen receptor T (CAR-T) cells, bispecific antibodies, and antibody–drug conjugates (ADC), which have already been approved in the treatment of acute lymphoblastic leukemia (ALL)/acute myeloid leukemia (AML). In addition, immune checkpoint inhibitors (ICIs), the pattern recognition receptors (PRRs), i.e., NOD-like receptors (NLRs), Toll-like receptors (TLRs), and several kinds of therapy antibodies are well on their way to showing significant benefits for patients with these diseases. This review summarizes the current knowledge of modern methods used in selected pediatric malignancies and presents therapies that may hold promise for the future.

Blockade of Nuclear Factor-Κb (NF-Κb) Pathway Using Bay 11-7082 Enhances Arsenic Trioxide-Induced Antiproliferative Activity in U87 Glioblastoma Cells

BACKGROUND

Glioblastoma (GBM), the most aggressive and common form of glioma, accounts for over 13,000 death per year in the United States which indicates the importance of developing novel strategies for the treatment of this fatal malignancy. Although Arsenic trioxide (ATO) hinders the growth and survival of GBM cells, the requirement of concentrations higher than 4 µM for triggering apoptotic cell death has questioned its safety profile. Since the NF-κB signaling pathway plays a crucial role in tumorigenesis and chemo-resistance, targeting this oncogenic pathway may sensitize GBM cells to lower concentrations of ATO.

METHODS

Anti-tumor effects of ATO as monotherapy and in combination with Bay 11-7082 were determined using MTT, crystal violet staining, Annexin V/PI staining and scratch assays. Quantitative reverse transcription-PCR (qRT-PCR) analysis was applied to elucidate the molecular mechanisms underlying the anti-tumor activity of this combination therapy.

RESULTS

Our results revealed that ATO and Bay 11-7082 synergistically inhibited the proliferation and survival of GBM cells. Also, it was revealed that NF-κB inhibition using Bay 11-7082 enhanced the inhibitory effects of ATO on migration of GBM cells via suppressing the expression of NF-κB target genes such as TWIST, MMP2, ICAM-1, and cathepsin B. Furthermore, combination treatment of GBM cells with ATO and Bay 11-7082 significantly induce apoptotic cell death coupled with downregulation of NF-κB anti-apoptotic target genes including Bcl-2 and IAP family members.

CONCLUSION

Altogether, these findings suggest that combination therapy with ATO and Bay 11-7082 may be a promising strategy for the treatment of GBM.

Toll-like receptors (TLRs): An old family of immune receptors with a new face in cancer pathogenesis

In the dark path of tumorigenesis, the more carefully the cancer biology is studied, the more brilliant answers could be given to the countless questions about its orchestrating derivers. The identification of the correlation between Toll-like receptors (TLRs) and different processes involved in carcinogenesis was one of the single points of blinding light highlighting the interconnection between the immune system and cancer. TLRs are a wide family of single-pass membrane-spanning receptors that have developed through the evolution to recognize the structurally conserved molecules derived from microorganisms or damaged cells. But this is not everything about these receptors as they could orchestrate several downstream signalling pathways leading to the formation or suppression of cancer cells. The present review is tempted to provide a concise schematic about the biology and the characters of TLRs and also summarize the major findings of the regulatory role of TLRs and their associated signalling in the pathogenesis of human cancers.