Cycloastragenol protects against glucocorticoid-induced osteogenic differentiation inhibition by activating telomerase.

Glucocorticoid-induced osteoporosis (GIOP) that is mainly featured as low bone density and increased risk of fracture is prone to occur with the administration of excessive glucocorticoids. Cycloastragenol (CAG) has been verified to be a small molecule that activates telomerase. Studied showed that up-regulated telomerase was associated with promoting osteogeneic differentiation, so we explored whether CAG could promote osteogenic differentiation to protect against GIOP and telomerase would be the target that CAG exerted its function. Our results demonstrated that CAG prominently increased the ALP activity, mineralization, mRNA of runt-related transcription factor 2, osteocalcin, osteopontin, collagen type I in both MC3T3-E1 cells and dexamethasone (DEX)-treated MC3T3-E1 cells. CAG up-regulated telomerase reverse transcriptase and the protective effect of CAG was blocked by telomerase inhibitor TMPyP4. Moreover, CAG improved bone mineralization in DEX-induced bone damage in a zebrafish larvea model. Therefore, the study showed that CAG could alleviate the osteogenic differentiation inhibition induced by DEX in vitro and in vivo, and CAG might be considered as a candidate drug for the treatment of GIOP.

Novel Sigma-2 receptor ligand A011 overcomes MDR in adriamycin-resistant human breast cancer cells by modulating ABCB1 and ABCG2 transporter function.

Multidrug resistance (MDR) is thought to be one of the main reasons for the failure of chemotherapy in cancers. ATP-binding cassette subfamily B member 1 (ABCB1) or P-glycoprotein (P-gp) and ATP-binding cassette subfamily G member 2 (ABCG2) play indispensable roles in cancer cell MDR. Sigma-2 (σ2) receptor is considered to be a cancer biomarker and a potential therapeutic target due to its high expression in various proliferative tumors. Recently, σ2 receptor ligands have been shown to have promising cytotoxic effects against cancer cells and to modulate the activity of P-glycoprotein (ABCB1) in vitro experiments, but their specific effects and mechanisms remain to be elucidated. We found that A011, a σ2 receptor ligand with the structure of 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline, showed promising cytotoxicity against breast cancer MCF-7 and adriamycin-resistant MCF-7 (MCF-7/ADR), induced apoptosis, and reversed adriamycin (ADR) and paclitaxel resistance in MCF-7/ADR cells. Furthermore, we demonstrated that A011 increased the accumulation of rhodamine 123 and mitoxantrone in MCF-7/ADR cells. A011 significantly decreased the ATPase activity of the ABCB1 and down-regulated ABCG2 protein expression. In addition, A011, administered alone or in combination with ADR, significantly inhibited tumor growth in the MCF-7/ADR tumor-bearing nude mouse model. A011 may be a potential therapeutic agent for the treatment of tumor resistance.

A011, a novel small-molecule ligand of σ2 receptor, potently suppresses breast cancer progression via endoplasmic reticulum stress and autophagy.

Breast cancer has surpassed lung cancer to become the most commonly diagnosed cancer in women worldwide. Sigma-2 (σ2) receptor is considered to be a potential therapeutic target for breast cancer because of its high expression in breast cancer cells and low expression in normal breast cells. Many σ2 ligands have been reported to have excellent anticancer activity, but their mechanism of action has not been fully elucidated. We discovered that A011 had high affinity and selectivity for σ2 receptor, reduced proliferation in five cancer cell lines, and significantly inhibited the monoclonal formation ability of MCF-7 cells. Furthermore, A011 rapidly increased the levels of intracellular Ca2+ and reactive oxygen species and induced autophagy. Molecular pharmacology studies revealed that A011 induced endoplasmic reticulum stress, activated the PERK-eIF2α-CHOP pathway and inhibited the activation of the PI3K-Akt-mTOR pathway, leading to cell apoptosis. In an in vivo tumor model, A011 showed obvious anti-tumor activity and no significant toxicity. More importantly, our study demonstrated for the first time that endoplasmic reticulum stress is the main mechanism of anti-cancer effects for σ2 ligands, at least for A011. A011 may potentially be useful as a therapeutic agent for treating breast cancer.

Kaempferol Ameliorates the Inhibitory Activity of Dexamethasone in the Osteogenesis of MC3T3-E1 Cells by JNK and p38-MAPK Pathways.

Kaempferol has been reported to exhibit beneficial effect on the osteogenic differentiation in mesenchymal stem cells (MSC) and osteoblasts. In our previous study, dexamethasone (DEX) demonstrated inhibitory effect on MC3T3-E1 cells differentiation. In this study, we mainly explored the protective effect of kaempferol on the inhibitory activity of DEX in the osteogenesis of MC3T3-E1 cells. We found that kaempferol ameliorated the proliferation inhibition, cell cycle arrest, and cell apoptosis and increased the activity of alkaline phosphatase (ALP) and the mineralization in DEX-treated MC3T3-E1 cells. Kaempferol also significantly enhanced the expression of osterix (Osx) and runt-related transcription factor 2 (Runx2) in MC3T3-E1 cells treated with DEX. In addition, kaempferol attenuated DEX-induced reduction of cyclin D1 and Bcl-2 expression and elevation of p53 and Bax expression. Kaempferol also activated JNK and p38-MAPK pathways in DEX-treated MC3T3-E1 cells. Furthermore, kaempferol improved bone mineralization in DEX-induced bone damage in a zebrafish larvae model. These data suggested that kaempferol ameliorated the inhibitory activity of DEX in the osteogenesis of MC3T3-E1 cells by activating JNK and p38-MAPK signaling pathways. Kaempferol exhibited great potentials in developing new drugs for treating glucocorticoid-induced osteoporosis.

Prediction of the mechanisms of Xiaoai Jiedu Recipe in the treatment of breast cancer: A comprehensive approach study with experimental validation.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional Chinese medicine (TCM) holds a great promise for preventing complex chronic diseases through a holistic way. Certain Chinese medicine formulae from TCM are effective for treating and preventing cancer in clinical practice. Xiaoai Jiedu Recipe (XJR) is a Chinese medicine formula that has been used to treat breast cancer (BC). However, its active ingredients and therapeutic mechanisms on tumor are unclear. Therefore, further investigation is necessary. AIM OF THE STUDY: This study aims to elucidate the active compounds of XJR and its molecular mechanisms for the treatment of BC. MATERIALS AND METHODS: A comprehensive approach was used to clarify the pharmacodynamic basis of XJR and its pharmacological mechanism, including the acquisition of differentially expressed genes of BC, screening of active ingredients and their targets, construction of complex internetwork between drugs and diseases, and analysis of the key subnetwork. Finally, these results were validated by in vitro experiments and comparison with literature reviews. RESULTS: By using bioinformatics, 5211 differentially expressed genes of BC were identified, more than half of them had been reported in previous studies. By using network analysis, 113 potential bioactive compounds in the ten component herbs of XJR and 157 BC-related targets were identified, which were significantly enriched in 85 pathways and 1321 GO terms. The in vitro studies showed that quercetin and ursolic acid, the active components of XJR, could effectively inhibit the proliferation of breast cancer cells, and the combination of the two components could significantly decrease the mitochondrial membrane potential and suppress the activation of PI3K-Akt signaling pathway, thus inducing apoptosis of cancer cells. CONCLUSIONS: XJR played an important role in anti-BC through multi-component, multi-target and multi-pathway mechanisms, in which quercetin and ursolic acid may be the key active components. The anticancer effect of multi-component application was better than that of a single component. This study not only deepened our understanding of the role of TCM in the prevention and treatment of diseases, but also provided a reference for the in-depth research, development and application of the ancient medicine.

Geniposide Alleviates Glucocorticoid-Induced Inhibition of Osteogenic Differentiation in MC3T3-E1 Cells by ERK Pathway.

Glucocorticoid (GC) therapy is the leading cause of secondary osteoporosis and the therapeutic and preventative drugs for GC-induced osteoporosis are limited. In this study, we investigated the protective effects of geniposide on dexamethasone (DEX)-induced osteogenic inhibition in MC3T3-E1 cells. The results showed that there was no obvious toxicity on MC3T3-E1 cells when geniposide was used at the doses ranging from 1 to 75 µM. In DEX-treated MC3T3-E1 cells, geniposide promoted the alkaline phosphatase (ALP) activity and the mineralization. In addition, geniposide also significantly increased the mRNA and protein expression of osteopontin (OPN), Runt-related transcription factor 2 (Runx2), and Osterix (Osx) in DEX-treated MC3T3-E1 cells. Furthermore, geniposide activated ERK pathway in DEX-treated MC3T3-E1 cells. The ERK activation inhibitor U0126 and glucagon-like peptide-1 (GLP-1) receptor antagonist exendin 9-39 abolished the geniposide-induced activation of ERK and inhibited the protective effect of geniposide. Taken together, our study revealed that geniposide alleviated GC-induced osteogenic suppression in MC3T3-E1 cells. The effect of geniposide was at least partially associated with activating ERK signaling pathway via GLP-1 receptor. Geniposide might be a potential therapeutic agent for GC-induced osteoporosis.