Faqing Tian

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. 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. 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. Our findings highlight the potential of boanmycin as a promising novel therapeutic option for treating MM, particularly in patients with BTZ resistance.

Objectives: 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. Methods: 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. Results: 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. Conclusions: Boanmycin may overcome venetoclax resistance and offer therapeutic benefits for patients with venetoclax-resistant AML.

Plenty of factors affect the oncogenesis and progression of colorectal cancer in the tumor microenvironment, including various immune cells, stromal cells, cytokines, and other factors. Chemokine is a member of the cytokine superfamily. It is an indispensable component in the tumor microenvironment. Chemokines play an antitumor or pro-tumor role by recruitment or polarization of recruiting immune cells. Meanwhile, chemokines, as signal molecules, participate in the formation of a cross talk among signaling pathways and non-coding RNAs, which may be involved in promoting tumor progression. In addition, they also function in immune escape. Chemokines are related to drug resistance of tumor cells and may even provide reference for the diagnosis, therapy, and prognosis of patients with colorectal cancer.

Background: Myeloma cells retain B cell functions, considered to be potential antigen presenting cells, yet there is little information regarding promoting Th2 cell proliferation or the direct effects to myeloma on the Th2 cells stimulated by microbial antigens-loaded myeloma cells. Methods: Mixed lymphocyte reaction was used colorimetric assays via CCK8-kit. Surface molecular expression was performed by flow cytometry, cells sorting using microbeads. The concentrations of cytokines in serum were assessed using an ELISA kit. Clonogenic assay were performed in a methylcellulose culture system. Statistical analysis was assessed using the Student’s t-test or one-way analysis of variance for multiple comparisons test. Results: The expression of HLA-DR, CD80 and CD40 on RPMI8266 cell membrane surface was upregulated by interaction with interferon-γ and/or Bacillus Calmette-Guerin Vaccine (BCGV). RPMI8266 cells were able to induce the mixed lymphocyte reaction in a dose-dependent fashion. The Th2 ratio induced by RPMI8266 treated by BCGV and interferon-γ (treated-RPMI8266) cells was only slightly greater than by untreated-tumor cells, but the serum IL-4 level secreted by Th2 cells was markedly higher in treated-RPMI8266 cells group. Th2 cells stimulated by treated-myeloma cells could directly promote treated-myeloma cell clonogenicity in a dose-dependent manner. Anti-HLADR IgG2b completely blocked increased of IL-4 secretion by Th2 cells stimulated by treated-myeloma cells, while also blocked enhancing the clonogenicity of treated tumor cells stimulated by MM-Th2 cells. Conclusions: These results indicate that a novel mechanism of myeloma pathogenesis in myeloma cells could act as an APC to present microbial Ags to Th2 cells, promoting Th2 cell proliferation, consequently facilitating tumor development by close interaction between Th2 myeloma cells. Taken together, the microbial Ag presenting course of MM-Th2-MM interactions—restricted by MHC class-II—may result in tumor development such that all factors involved in the system could have a potential for myeloma therapeutic intervention.

The antibiotic chloramphenicol may be an effective new agent for inhibiting the growth of multiple myeloma