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Background: Multiple myeloma (MM) is a hematological malignancy characterized by uncontrolled proliferation of plasma cells and is currently incurable. Despite advancements in therapeutic strategies, resistance to proteasome inhibitors, particularly bortezomib (BTZ), poses a substantial challenge to disease management. This study aimed to explore the efficacy of boanmycin, a novel antitumor antibiotic, in overcoming resistance to BTZ in MM. Methods: BTZ-resistant cells were generated over a period of at least 6 months by gradually increasing the concentration of BTZ. The viability of MM cell lines and patient bone marrow mononuclear cells (BMMCs) was measured via the CCK8 reagent. The protein levels of cleaved caspase 3, cleaved caspase 7, cleaved PARP, PARP, p-JNK, JNK, and γ-H2AX were analyzed through Western blot. Cellular morphology was observed via transmission electron microscopy. Colony formation ability was evaluated, and cell apoptosis and the cell cycle were detected through flow cytometry. Xenograft experiments were conducted to evaluate the growth of MM cells in vivo. Results: Our results demonstrated that boanmycin effectively inhibited cell proliferation and colony formation, and triggered apoptosis in both BTZ-sensitive and BTZ-resistant MM cells. The combination of boanmycin with BTZ had greater inhibitory effects than either drug alone. Furthermore, boanmycin significantly suppressed MM cell growth in immunodeficient mouse xenograft models without inducing distinct toxic side effects. Notably, boanmycin markedly killed patient-derived MM cells ex vivo. Mechanistically, boanmycin not only disrupts the cell cycle and causes DNA damage but also exerts its antitumor effects by inducing endoplasmic reticulum (ER) functional impairment. Conclusions: Our findings highlight the potential of boanmycin as a promising novel therapeutic option for treating MM, particularly in patients with BTZ resistance. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the efficacy of boanmycin, a clinical drug used for head and neck cancers, in the treatment of acute myeloid leukemia (AML), particularly in venetoclax-resistant AML cells. The cell viability assay was conducted to measure the inhibitory effects of boanmycin on the AML cell lines and patient primary cells using the CCK8 reagent. The colony formation assay was performed to evaluate the colony formation ability of HL60 and venetoclax-resistant HL60 (HL60-res) cells with or without boanmycin treatment. Flow cytometry was performed to detect cell apoptosis level, and Western blot was used to assess changes in apoptosis-related proteins. Our findings reveal that boanmycin significantly inhibits AML cell proliferation and colony formation, and induces apoptosis. Importantly, boanmycin exhibits substantial inhibitory effects on venetoclax-resistant cells, and suppresses the proliferation of peripheral blood mononuclear cells (PBMCs) or bone marrow mononuclear cells (BMMCs) derived from newly diagnosed and relapsed AML patients. Boanmycin may overcome venetoclax resistance and offer therapeutic benefits for patients with venetoclax-resistant AML. [ABSTRACT FROM AUTHOR]

Objective：To investigate the promotive effect of dendritic cells(DCs) on proliferation of CRTH2 (CD4(+)CD294(+)Th2) cells and the influence of CRTH2 cells on secretion of immunoglobulin from B cells so as to provide a new approach for amplification and sorting of Th2 cells. Methods：DCs were induced from peripheral blood mononuclear cells, then the loaded-BCGV-Ag-DCs were cocultured with T cells, and the mixed lymphocyte reaction(MLR) was performed by CCK8 method. The phenotypes of DCs and CRTH2 cells were detected by flow cytometry. CRTH2 cells sorted by MACS were co-cultured with B cells for 5 days to detect the secretion of immunoglobulin. Results：The subsets and absolute number CRTH2 cells were significantly increased by loaded-BCGV-Ag-DCs. The levels of IgG, IgA and IgE were higher increased in supernatant of CRTH2 and B cell co-culture system than that in control group or that in transwell group(P<0.05). Conclusion：The proliferation of CRTH2 cells can be greatly promoted by loaded-BCGV-Ag-DCs, and the CRTH2 cells can help B cells to secrete IgG, IgA and IgE.

This study was purposed to investigate the possibility of differentiating the acute promyelocytic leukemia (APL) cells into dendritic cells (DCs) induced by all-trans retinoic acid (ATRA) combined with classic cytokines so as to provide a new approach for development of APL-DC vaccine. The bone marrow mononuclear cells from a new diagnosed patient with APL and HL-60 cells were separately cultured in complete culture medium. The cells were treated by ATRA, GM-CSF, IL-4 and TNFalpha in experimental groups and no ATRA was added in control and blank control groups. The cell morphology was observed by light microscopy, the phenotypes of DCs were detected by flow cytometry, the level of IL-12 was measured by using ELISA, the mixed lymphocyte reaction (MLR) and effect of cytotoxic T-lymphocyte (CTL) were assayed by MTT method. The results indicated that in experiment groups, the cells had dendritic appearance and cytogenetic characteristics of APL; expression of CD1a, CD83, CD80, CD86, HLA-DR and CD1d as well as level of IL-12 obviously increased; the MLR and CTL effects were significant, but increase of CD1a expression in HL60-DCs did not show statistical difference from control and blank control groups. It is concluded that ATRA can successfully induce APL cells to differentiate into functionally mature DSs which obviously mediate MLR and CTL effects. The APL-DCs derived by ATRA can notably express CD1d that may activate CD1d-restricted NKT cells and promote proliferation of NRT cells. The exact mechanism of which should be further studied.

Programmed death-1 ligand-1(PD-L1) is a recently identified member of the B7 family molecules and is shown to mediate the inhibition of immune responses. This study was purposed to enhance the weak immunological function of dendritic cells (DCs) derived from the patients with chronic myelocytic leukemia (CML) by blockade of the expression of PD-L1. Bone marrow mononuclear cells (BMMNCs) of CML patients were induced into DCs in the presence of cytokine cocktail of rhGM-CSF, rhIL-4 and TNF-alpha. The phenotypes of DCs were detected by flow cytometry, mixed lymphocyte reaction was analyzed by MTT assay and IFN-gamma, IL-2 and IL-10 in the cell culture supernatant were detected by ELISA. The results showed that the expression of PD-L1 on CML-DCs was upregulated with the maturation of CML-DCs. PD-L1-blockaded DCs could enhance T lymphocyte proliferation, increase the secretion of IL-2 and IFN-gamma, and inhibit the production of IL-10. Taken together, PD-L1-blockaded DCs originated from CML cells had more potent immunostimulatory capability. It is concluded that PD-L1 blockaded can enhance the function of CML-DCs. This approach presents new possibilities for achieving anti-tumor immunity by DC-based vaccination.