Bone metastasis is a leading cause of morbidity and mortality in advanced prostate cancer (PCa). Downexpression of miR-133a-3p has been found to contribute to the progression, recurrence and distant metastasis in PCa. However, clinical significance of miR-133a-3p in bone metastasis of PCa, and the biological role of miR-133a-3p and its molecular mechanisms underlying bone metastasis of PCa remain unclear. miR-133a-3p expression was evaluated in 245 clinical PCa tissues by real-time PCR. Statistical analysis was performed to evaluate the clinical correlation between miR-133a-3p expression and clinicopathological features, and overall and bone metastasis-free survival in PCa patients. The biological roles of miR-133a-3p in the bone metastasis of PCa were investigated both in vitro and in vivo. Bioinformatics analysis, real-time PCR, western blot and luciferase reporter analysis were applied to demonstrate the relationship between miR-133a-3p and its potential targets. Western blotting and luciferase assays were examined to identify the underlying pathway involved in the anti-tumor role of miR-133a-3p. Clinical correlation of miR-133a-3p with its targets was verified in human PCa tissues. miR-133a-3p expression is reduced in PCa tissues compared with the adjacent normal tissues and benign prostate lesion tissues, particularly in bone metastatic PCa tissues. Low expression of miR-133a-3p is significantly correlated with advanced clinicopathological characteristics and shorter bone metastasis-free survival in PCa patients by statistical analysis. Moreover, upregulating miR-133a-3p inhibits cancer stem cell-like phenotypes in vitro and in vivo, as well as attenuates anoikis resistance in vitro in PCa cells. Importantly, administration of agomir-133a-3p greatly suppresses the incidence of PCa bone metastasis in vivo. Our results further demonstrate that miR-133a-3p suppresses bone metastasis of PCa via inhibiting PI3K/AKT signaling by directly targeting multiple cytokine receptors, including EGFR, FGFR1, IGF1R and MET. The negative clinical correlation of miR-133a-3p with EGFR, FGFR1, IGF1R, MET and PI3K/AKT signaling activity is determined in clinical PCa tissues. Our results unveil a novel mechanism by which miR-133a-3p inhibits bone metastasis of PCa, providing the evidence that miR-133a-3p may serve as a potential bone metastasis marker in PCa, and delivery of agomir-133a-3p may be an effective anti-bone metastasis therapeutic strategy in PCa.

Mounting evidence demonstrates uncontrolled endoplasmic reticulum (ER) stress responses can activate the inflammasome, which generally results in endothelial dysfunction, a major pathogenetic factor of chronic inflammatory diseases such as atherosclerosis. Salvianolic acid B (SalB), produced by Radix Salviae, exerts antioxidative and anti‐inflammatory activities in multiple cell types. However, SalB’s effects on ER stress‐related inflammasome and endothelial dysfunction remain unknown. Here, we showed SalB substantially abrogated ER stress‐induced cell death and reduction in capillary tube formation, with declined intracellular reactive oxygen species (ROS) amounts and restored mitochondrial membrane potential (MMP), as well as increased expression of HO‐1 and SOD2 in bone marrow‐derived endothelial progenitor cells (BM‐EPCs). ER stress suppression by CHOP or caspase‐4 siRNA transfection attenuated the protective effect of SalB. Additionally, SalB alleviated ER stress‐mediated pyroptotic cell death via the suppression of TXNIP/NLRP3 inflammasome, as evidenced by reduced cleavage of caspase‐1 and interleukin‐ (IL‐) 1β and IL‐18 secretion levels. Furthermore, this study provided a mechanistic basis that AMPK/FoxO4/KLF2 and Syndecan‐4/Rac1/ATF2 signaling pathway modulation by SalB substantially prevented BM‐EPCs damage associated with ER stress by decreasing intracellular ROS amounts and inducing NLRP3‐dependent pyroptosis. In summary, our findings identify that ER stress triggered mitochondrial ROS release and NLRP3 generation in BM‐EPCs, while SalB inhibits NLRP3 inflammasome‐mediated pyroptotic cell death by regulating the AMPK/FoxO4/KLF2 and Syndecan‐4/Rac1/ATF2 pathways. The current findings reveal SalB as a potential new candidate for the treatment of atherosclerotic heart disease.

Perillaldehyde (PAH), one of the active ingredients of the traditional Chinese medicine (TCM) plant Perilla frutescens, is widely used and exerts crucial anti-cancer activities. The aim of current study is to illustrate the potential mechanisms of PAH-mediated regulation of bone metastasis and osteoclastogenesis in prostate cancer (PCa) cell lines. Effects of PAH on proliferation, invasion and migration of PC-3 cells were assessed with the Cell Counting Kit-8 (CCK-8) assay and Transwell assays, respectively. Effects of PAH on stem cell characteristics of PC-3 cells were evaluated by cell-matrix adhesion assay, colony formation assay, spheroid formation assay, as well as western blot . The anti-metastasis and anti-osteoclastogenesis activity of PAH in RAW264.7 cells was examined by osteoclast differentiation assay and western blot. The protein levels of CD133 and CD44 in PC-3 cells and the activity of nuclear factor kappa B (NF-κB) signaling pathway in RAW264.7 cells were measured by western blot. PAH suppressed proliferation, invasion and migration of PC-3 cells, prevented stem cell characteristics including cell-matrix adhesion, colony formation, spheroid formation as well as CD133 and CD44 expression. PAH inhibited bone metastasis and osteoclastogenesis via repressing the activation of NF-κB pathway as well as (RANKL) – and cancer cell-induced osteoclastogenesis in PCa cells. These findings suggested the potential therapeutic effects of PAH on the metastasis of patients with PCa.

Exosomes produced by mesenchymal stem cells (MSCs) have vascular generative properties and are considered new effective candidates for the treatment of bone defects as alternatives to cell therapy. Improving the pro-regenerative function and efficacy of exosomes has been a popular research topic in the field of orthopaedics. We prepared mesoporous bioactive glass (mBG) microspheres via the template method. The ionic products of mBGs used to treat MSCs were extracted, and the effects of exosomes secreted by MSCs on osteoblast (OB) and macrophage (MP) behaviour and bone defect repair were observed in vivo (Micro-CT, H&E, Masson, and immunofluorescence staining for BMP2, COL1, VEGF, CD31, CD163, and iNOS). The mBG spheres were successfully prepared, and the Exo-mBG were isolated and extracted. Compared with those in the blank and Exo-Con groups, the proliferation and osteogenic differentiation of OBs in the Exo-mBG group were significantly greater. For example, on Day 7, OPN gene expression in the Ctrl-Exo group was 3.97 and 2.83 times greater than that in the blank and Exo-mBG groups, respectively. In a cranial defect rat model, Exo-mBG promoted bone tissue healing and angiogenesis, increased M2 macrophage polarisation and inhibited M1 macrophage polarisation, as verified by micro-CT, H&E staining, Masson staining and immunofluorescence staining. These effects may be due to the combination of a higher silicon concentration and a higher calcium-to-phosphorus ratio in the mBG ionic products. This study provides insights for the application of exosomes in cell-free therapy and a new scientific basis and technical approach for the utilisation of MSC-derived exosomes in bone defect repair. Our study demonstrated that exosomes produced by mBG-stimulated MSCs have excellent in vitro and in vivo bone-enabling and immunomodulatory functions and provides insights into the use of exosomes in clinical cell-free therapies.