Oroxylin A suppresses breast cancer-induced osteoclastogenesis and osteolysis as a natural RON inhibitor.

BACKGROUND: Malignant breast cancer cells trigger the over-activation of osteoclast precursor cells, leading to bone loss and severe pain. Targeted inhibition of osteoclast differentiation has emerged as an important strategy for treating bone syndromes induced by breast cancer. PURPOSE: The objective is to discover natural osteoclast inhibitor to treat osteoclastogenesis and bone destruction induced by breast cancer, and clarify the specific mechanisms. METHODS: Recepteur d'origine Nantais (RON) protein was employed to search the natural osteoclast inhibitor for breast cancer-induced osteoclastogenesis by molecular docking, molecular dynamics simulation and cellular thermal shift assay (CETSA). In the in vitro experiment, breast cancer MDA-MB-231 cell-conditioned medium (MDA-MB-231 CM) was used to induce osteoclastogenesis in murine bone marrow-derived macrophages (BMMs), aiming to elucidate the effects and mechanisms of the natural osteoclast inhibitor. In the in vivo model, MDA-MB-231 cells was injected into the mouse tibia to evaluate the therapeutic effect of drug on breast cancer-induced bone destruction. RESULTS: We discovered a significant increase in the expression of RON during MDA-MB-231 CM-induced osteoclast differentiation in vitro. Molecular docking analysis found that oroxylin A (OA), a flavonoid derived from the Chinese medicine Scutellaria baicalensis Georgi, showed binding ability with RON, while its impact and mechanism on breast cancer-induced osteoclastogenesis and osteolysis remains unclear. Molecular dynamics simulation and CETSA further revealed that OA bound directly to the RON protein, and it also decreased RON expression in breast cancer CM-induced osteoclastogenesis. Correspondingly, OA suppressed the MDA-MB-231 CM-induced osteoclastogenesis and bone resorption in vitro. The downstream signals of RON including Src and NFATc1, as well as the osteoclast-specific genes, were downregulated by OA. Of interesting, the suppressive effect of OA on osteoclastogenesis induced by MDA-MB-231 CM was abolished after RON was knocked down by the specific RON-siRNA, this further confirmed that OA showed inhibitory effects on osteoclasts through targeting RON. In addition, we found that OA attenuated MDA-MB-231 cell-induced osteolysis and reduced the number of osteoclasts in vivo. CONCLUSION: Our results indicate that OA acts as a natural RON inhibitor to suppress breast cancer-induced osteoclastogenesis and osteolysis. This provides new strategy for treating breast cancer-induced bone destruction and related syndromes.

Erianin serves as an NFATc1 inhibitor to prevent breast cancer-induced osteoclastogenesis and bone destruction.

INTRODUCTION: Breast cancer-related bone metastasis can lead to skeletal-related events (SREs), which decrease patient quality of life. Inhibition of osteoclastogenesis is a key treatment for SREs; however, the availability of clinical drugs remains limited, and all existing ones disrupt physiological bone formation, while exhibiting no effect on patient survival time. OBJECTIVES: This study aimed to identify a novel osteoclast inhibitor for the treatment of breast cancer-induced SREs. METHODS: The MDA-MB-231 breast cancer cell-induced bone loss model was used to investigate the therapeutic effects of erianin in vivo. Then, we evaluated the inhibitory effects of erianin on osteoclastogenesis and signalling in bone marrow-derived macrophages (BMMs) induced by conditioned medium from MDA-MB-231 breast cancer cells (231 CM) and receptor activator of nuclear factor-κB ligand (RANKL) in vitro. Next, a Cellular Thermal Shift Assay and siRNA-mediate knockdown were performed, to investigate the target of erianin during osteoclast formation. The effects of erianin on human osteoclastogenesis were evaluated using CD14+ monocytes obtained from patients with breast cancer. RESULTS: Erianin effectively improved breast cancer cells-induced bone destruction at doses of 2 and 20 mg/kg/day in vivo, while suppressing osteoclastogenesis and the upregulation of SRC-NFATc1, INTEGRIN ß3-MMP9 signals induced by 231 CM and RANKL in vitro. Furthermore, erianin interacted with NFATc1 but not SRC, and Nfatc1 knockdown eliminated the inhibitory effects of erianin on osteoclastogenesis. Notably, lower expression of NFATc1 positively correlated with longer survival in patients with cancer and a high risk of bone metastasis. We further revealed that 62.5-250 nM erianin suppresses NFATc1 and excessive osteoclastogenesis in CD14+ monocytes from patients with breast cancer. CONCLUSION: Erianin acts as an NFATc1 inhibitor that attenuates breast cancer-induced osteoclastogenesis and bone destruction.

Immune-Cell-Based Therapy for COVID-19: Current Status.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global pandemic. The interplay between innate and adaptive immune responses plays a crucial role in managing COVID-19. Cell therapy has recently emerged as a promising strategy to modulate the immune system, offering immense potential for the treatment of COVID-19 due to its customizability and regenerative capabilities. This review provides an overview of the various subsets of immune cell subsets implicated in the pathogenesis of COVID-19 and a comprehensive summary of the current status of immune cell therapy in COVID-19 treatment.

Flot2 deficiency facilitates B cell-mediated inflammatory responses and endotoxic shock.

Sepsis is a life-threatening disease characterized by multiple organ dysfunction. B cells play a pivotal role in sepsis. Here, we first observed the significantly reduced Flot2 gene expression in B cells from patients with bacterial sepsis and endotoxin-induced septic mice. However, the effects of Flot2 on sepsis and B-cell immunity remain unknown. Thus, we sorted B cells from Flot2 knockout (Flot2-/- ) mice, RNA-seq revealed significantly upregulated effector B cell (Beff) cytokines such as Il6, Il1b and Cxcl10 after Flot2 deficiency, while it showed no effect on the expression of regulatory B cell (Breg) cytokines such as Il10, Tgfb. Consistently, elevated Beff cytokine IL-6 and unchanged Breg cytokine IL-10 were shown in B cells from Flot2-/- mice. Similar results were subsequently observed in B cell-specific Flot2 knockout chimeric mice. Notably, Flot2 deficiency aggravated sepsis with increased lung injury and shortened survival time in vivo by facilitating Beffs but not Bregs. Taken together, our data identify Flot2 as a novel controller of B cells, Flot2 deficiency amplifies inflammation by affecting Beffs to participate in the pathogenesis and progression of sepsis.

Polyphyllin VII protects from breast cancer-induced osteolysis by suppressing osteoclastogenesis via c-Fos/NFATc1 signaling.

Bone is a preferred metastatic site of advanced breast cancer and the 5-year overall survival rate of breast cancer patients with bone metastasis is only 22.8%. Targeted inhibition of osteoclasts can treat skeletal-related events (SREs) in breast cancer patients. Polyphyllin VII (PP7), a pennogenyl saponin isolated from traditional Chinese herb Paris polyphylla, exhibits strong anti-inflammatory and anti-cancer activities. In this study, we evaluated the effect of PP7 on metastatic breast cancer-induced bone destruction in vivo and the underlying mechanisms. We found that intraperitoneal injection of 1 mg/kg PP7 significantly ameliorated the breast cancer MDA-MB-231 cell-induced osteolysis in mice. Mechanistically, PP7 (0.125-0.5 µM) inhibited the conditioned medium of MDA-MB-231 cells (MDA-MB-231 CM)-induced osteoclast formation in bone marrow-derived macrophages (BMMs). Furthermore, PP7 markedly reduced MDA-MB-231 CM-induced osteoclastic bone resorption and F-actin rings formation in vitro. During MDA-MB-231 CM-induced osteoclastogenesis, the activation of c-Fos and NFATc1 signaling was significantly downregulated by PP7, and finally osteoclast-related genes such as Oscar, Atp6v0d2, Mmp9 and ß3 integrin were decreased. In addition, the formation of osteoblast was promoted by PP7 treatment. Our current findings revealed PP7 as a potential safe agent for preventing and treating bone destruction in breast cancer patients with bone metastases.

IKKß increases neuropilin-2 and promotes the inhibitory function of CD9+ Bregs to control allergic diseases.

Regulatory B cells (Bregs) potently suppress immune disorders, including allergic contact hypersensitivity (CHS). IKKß overactivation is prominent in various inflammatory diseases. However, its effect on Bregs has not been defined. This study is to investigate the new regulator and inhibitory mechanism of Bregs. IkkßC46A transgenic mice with a Cys46 mutation, resulting in increased IKKß activation, were employed for analysis. IL-10-competent CD9+ Bregs were expanded in IkkßC46A mice and B cell specific-IkkßC46A mutation mice. IkkßC46A mutant CD9+ Bregs had stronger suppressive effects on CD4+ and CD8+ T cells in vitro and CHS responses in vivo. The inhibitory CD9+ Bregs from IkkßC46A mice were characterized by upregulated Neuropilin 2 (Nrp2) and IL-10 in comparison with that of Ikkßwt mice. Interestingly, increased expression of Nrp2 was observed in CD9+ Bregs compared with that of CD9- B cells in wild-type mice. The suppressive activity of wild-type CD9+ Bregs in vitro was attenuated by inhibition of Nrp2 on Bregs or silencing its ligand Sema3f on CD4+ T cells. Our findings delineate a distinct role of IKKß activation in enhancing Bregs to disturb the immune balance. It identifies Nrp2 as a novel regulatory molecule of Bregs that partly contributes to B cell-mediated immune tolerance.