Metastasis causes approximately 90% of breast cancer-related deaths in women. Previously, we have demonstrated that 2-dodecyl-6-methoxycyclohexa-2,5-diene- 1,4-dione (DMDD) remarkably inhibited the growth of human breast cancer cells with little toxicity. In this study, we investigated the toxicity and efficacy of DMDD to treat metastatic breast tumors using an in vivo mouse model of the 4T1 mammary carcinoma. DMDD caused no observable toxicity and significantly extended the survival of 4T1 tumor-bearing mice. DMDD effectively inhibited the growth of 4T1 cells in vitro, and suppressed the growth and metastasis of mammary tumor in vivo. The levels of inflammatory cytokines in the serum (TNF-α, IL-6, IL-12, TGF-β, and VEGF) were down regulated by DMDD. Immunohistochemical analysis demonstrated that the inhibition of tumor growth and metastasis was associated with activation of Bax, cleaved caspases-3 and -9, and down-regulation of Bcl-2, MMP-2 and -9, NF-κB and IκBα. We speculate that DMDD inhibits cytokine production in the tumor cells in mice, which leads to deactivation of NF-κB pathway, and consequently inhibits the expression of many anti-apoptosis and metastasis-promoting genes, such as Bcl-2 and MMPs. Collectively, our results demonstrate the potential of DMDD as a safe and effective antitumor agent in the treatment of late-stage breast cancer.

Doxorubicin (DOX) is an effective anthracycline anti-tumor antibiotic. Because of its cardiotoxicity, the clinical application of DOX is limited. Paeoniflorin (PEF), a monoterpene glucoside extracted from the dry root of Paeonia, is reported to exert multiple beneficial effects on the cardiovascular system. The present study was designed to explore the protective effect of PEF against DOX-induced cardiomyocyte apoptosis and the underlying mechanism. In cultured H9c2 cells, PEF (100 µmol/l) was added for 2 h prior to exposure to DOX (5 µmol/l) for 24 h. Cell viability, creatine kinase activity, cardiomyocyte apoptosis, intracellular reactive oxygen species (ROS) levels, and the expression of microRNA-1 (miR-1) and B-cell lymphoma 2 (Bcl-2) were measured following treatment with PEF and/or DOX. The results showed that treatment with DOX notably induced cardiomyocyte apoptosis, concomitantly with enhanced ROS generation, upregulated miR-1 expression and downregulated Bcl-2 expression. These effects of DOX were significantly inhibited by pretreatment of the cells with PEF. These results suggest that the inhibitory effect of PEF on DOX-induced cardiomyocyte apoptosis may be associated with downregulation of miR-1 expression via a reduction in ROS generation.

Reactive oxygen species (ROS)‑induced mitochondrial dysfunction plays an important role in cardiomyocyte apoptosis during myocardial ischemia/reperfusion (I/R) injury. Picroside Ⅱ, isolated from Picrorhiza scrophulariiflora Pennell (Scrophulariaceae), has been reported to protect cardiomyocytes from hypoxia/reoxygenation (H/R)‑induced apoptosis, but the exact mechanism is not fully clear. The aim of the present study was to explore the protective effects of picroside Ⅱ on H/R‑induced cardiomyocyte apoptosis and the underlying mechanism. In the H9c2 rat cardiomyocyte cell line, picroside Ⅱ (100 µg/ml) was added for 48 h prior to H/R. The results showed that picroside Ⅱ markedly inhibited H/R‑induced cardiomyocyte apoptosis. In addition, picroside Ⅱ was also able to decrease the opening degree of mitochondrial permeability transition pore (mPTP), increase the mitochondrial membrane potential, inhibit cytochrome c release from mitochondria to cytosol and downregulate caspase‑3 expression and activity concomitantly with the decreased ROS production. These results suggested that picroside Ⅱ inhibited H/R‑induced cardiomyocyte apoptosis by ameliorating mitochondrial function through a mechanism involving a decrease in ROS production.