Gut microbiota deficiency ameliorates multiple myeloma and myeloma-related bone disease by Th17 cells in mice models.

Purpose: Multiple myeloma, the second most common hematological tumor, is currently incurable. Multiple myeloma-related bone disease is a characteristic clinical symptom that seriously affects the survival and prognosis of patients. In recent years, gut microbiota has been shown to play an important role in the occurrence and development of multiple myeloma. However, whether and how it affects the development of myelomatous bone disease is unclear. Methods: To investigate the mechanism and influence of the microbiota on multiple myeloma and myeloma bone disease, a myeloma-gut microbiota deletion mice model was established. 16S rRNA sequencing was used to analysis of bacterial flora changes. Histochemical staining and bone micro-CT were used to assess the severity of bone disease. Bone marrow tumor load and spleen Th17 cells were detected by flow cytometry. Results: Histochemical staining revealed a reduced tumor burden after eliminating gut microbial communities in mice by administering a mixture of antibiotics. According to the 16S rRNA sequencing of intestinal contents, antibiotic treatment resulted in a significant change in the microbiota of the mice. Bone micro-CT demonstrated that antibiotic treatment could reduce bone lesions caused by myeloma while increasing mineral density, bone volume fraction, trabecular bone thickness, and trabecular number. Meanwhile, histochemical staining of the bone found that the enhanced bone resorption was weakened by the change of flora. These results were consistent with the concentration of IL17 in serum and the frequency of Th17 cells in spleen. Conclusions: Herein, the effects of the gut microbiome on myeloma bone disease are investigated for the first time, providing new insight into its pathogenesis and suggesting that gut microbiota may serve as a therapeutic target in multiple myeloma-associated bone diseases.

Obesity as a risk factor for multiple myeloma: insight on the role of adipokines.

Multiple myeloma (MM) is a hematologic disorder characterized by the accumulation of malignant plasma cells in the bone marrow. Genetic and environmental factors are contributed to the etiology of MM. Notably, studies have shown that obesity increases the risk of MM and worsens outcomes for MM patients. Adipokines play an important role in mediating the close association between MM and metabolic derangements. In this review, we summarize the epidemiologic studies to show that the risk of MM is increased in obese. Accumulating clinical evidence suggests that adipokines could display a correlation with MM. In vitro and in vivo studies have shown that adipokines are linked to MM, including roles in the biological behavior of MM cells, cancer-associated bone loss, the progression of MM, and drug resistance. Current and potential therapeutic strategies targeted to adipokines are discussed, proposing that adipokines can guide early patient diagnosis and treatment.

LGR4 promotes tumorigenesis by activating TGF-ß1/Smad signaling pathway in multiple myeloma.

Multiple myeloma (MM) is a common hematologic malignancy that remains incurable. Although accumulating evidence suggests that the leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4) plays a biological function in a variety of cancers, its biological function and molecular mechanisms in MM are unclear. In the present study, we found that LGR4 was significantly upregulated in MM tissues and cells. In vitro and in vivo experiments showed that knockdown of LGR4 significantly inhibited proliferation of MM cells, promoted apoptosis and arrested cell cycle in G1. Overexpression showed the opposite effect. Mechanistic studies revealed that LGR4 could interact with TGF-ß1 and regulate TGF-ß1 expression, thereby activating the TGF-ß1/Smad signaling pathway and promoting MM progression. LGR4 may be a potential new target for MM diagnosis and treatment.

NORAD promotes multiple myeloma cell progression via BMP6/P-ERK1/2 axis.

Multiple myeloma (MM) is one of the most common tumors of the hematological system and remains incurable. Recent studies have shown that long noncoding RNA NORAD is a potential oncogene in a variety of tumors. However, the general biological role and clinical value of NORAD in MM remains unknown. In this study, we measured NORAD expression in bone marrow of 60 newly diagnosed MM, 30 post treatment MM and 17 healthy donors by real-time quantitative polymerase chain reaction (qPCR). The NORAD gene was knockdown by lentiviral transfection in MM cell lines, and the effects of NORAD on apoptosis, cell cycle and cell proliferation in MM cells were examined by flow cytometry, CCK8 assay, EDU assay and Western blot, and the differential genes after knockdown of NORAD were screened by mRNA sequencing, followed by in vivo experiments and immunohistochemical assays. We found that knockdown of NORAD promoted MM cell apoptosis, induced cell cycle G1 phase arrest, and inhibited MM cell apoptosis in in vivo and in vitro experiments. Mechanistically, NORAD plays these roles through the BMP6/P-ERK1/2 axis. We discuss a novel mechanism by which NORAD acts pro-tumorigenically in MM via the BMP6/P-ERK1/2 axis.

The yin-yang effects of immunity: From monoclonal gammopathy of undetermined significance to multiple myeloma.

Multiple myeloma (MM) is the third most common malignant neoplasm of the hematological system. It often develops from monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) precursor states. In this process, the immune microenvironment interacts with the MM cells to exert yin and yang effects, promoting tumor progression on the one hand and inhibiting it on the other. Despite significant therapeutic advances, MM remains incurable, and the main reason for this may be related to the complex and variable immune microenvironment. Therefore, it is crucial to investigate the dynamic relationship between the immune microenvironment and tumors, to elucidate the molecular mechanisms of different factors in the microenvironment, and to develop novel therapeutic agents targeting the immune microenvironment of MM. In this paper, we review the latest research progress and describe the dual influences of the immune microenvironment on the development and progression of MM from the perspective of immune cells and molecules.