Phagocytosis of Bafilomycin A1-treated Apoptotic Neuroblastoma Cells by Bone Marrow–derived Dendritic Cells Initiates a CD8α+ Lymphocyte Response to Neuroblastoma

Abstract

This study aimed to determine whether bafilomycin A1 (Baf-A1), a vacuolar H-ATPase inhibitor, could promote an immune response after the induction of apoptosis in mouse neuroblastoma cells. Mouse neuro-2a cells were cultured in a medium containing Baf-A1, and apoptosis was evaluated by flow cytometry. To examine the influence in the phagocytic cell, CD11b spleen cells or bone marrow-derived dendritic cells (BM-DCs) were cocultured with Baf-A1-treated neuro-2a. Interferon-γ (IFN-γ) production was used as an index of the immune response, and CDDP was used as the negative control. When CD8α cells were cocultured with CD11b cells and Baf-A1-treated neuro-2a cells in the presence of CpG-oligodeoxynucleotide (CpG-ODN) (a toll-like receptor 9 [TLR-9] agonist), CD8α lymphocyte proliferation and secretion of IFN-γ were observed. Phagocytosis of apoptotic cells by BM-DCs was maximal after simultaneous stimulation with CpG-ODN and lipopolysaccharide (LPS; a TLR-4 agonist). IFN-γ secretion was maximal when Baf-A1-treated neuro-2a cells and CD8α lymphocytes were cocultured with BM-DCs and stimulated with CpG-ODN. In contrast, IFN-γ production was not increased when the cells were cultured with LPS. When cells were stimulated with both CpG-ODN and LPS, promotion of IFN-γ production by CpG-ODN was suppressed. Induction of apoptosis by Baf-A1 could possibly enhance antitumor immunity in patients receiving chemotherapy for neuroblastoma. Stimulation of BM-DCs with a TLR-9 agonist could promote antitumor activity after Baf-A1 treatment.

Influence of the chirality of carbon nanodots on their interaction with proteins and cells

“…The endocytosis pathway of CNDs can be investigated by evaluating the inhibition of certain internalization pathways by pharmacological/chemical inhibitors associated with 82 . In our case, we investigated the cellular uptake pathway of CNDs using the following chemical inhibitors: (i) Nocodazole 83 (an inhibitor of endocytosis of lager nanoparticles 82 , 84 , 85 , CAS No.31430-18-9, Sigma-Aldrich, Germany), (ii) Bafilomycin A1 84 (an inhibitor of phagocytosis 86 , 87 , CAS No. 88899-55-2, InvivoGen, France), (iii) Amiloride 88 (an inhibitor of micropinocytosis 89 , 90 , CAS No.…”

“…Presence of Bafilomycin A1 drastically reduced the uptake of CNDs. Thus, phagocytosis will be a major route of uptake of the CNDs 86 , 87 . In case of the N - CNDs also presence of Chlorpromazine reduced uptake of the CNDs.…”

Bafilomycin A1 Induces Caspase-Dependent Apoptosis and Inhibits Autophagy Flux in Diffuse Large B Cell Lymphoma

“…Bafilomycin A1, as an inhibitor of V-ATPase, inhibits H + from translocating into vesicle lumen therefore suppresses the acidosis of organelles such as lysosomes and endosomes [36][37]. High concentrations of bafilomycin A1 (0.1-1μM) has been widely used to inhibit autophagy flux by blocking the fusion between autophagosomes and lysosomes which is a critical step in late-stage autophagy [38][39].…”