Mechanisms of growth inhibition induced by methylene-substituted and ring-substituted dims in breast cancer cells

One in 8 women will be diagnosed with breast cancer in the United States and estrogen receptor (ER) status largely influences the type and subsequent success of treatment employed. Although ER-positive breast cancer can be treated with endocrine therapy, the more invasive ER-negative breast cancer is non-responsive to this therapy and cytotoxic agents are often utilized which are associated with many adverse side effects. Consequently, there is a genuine need to develop more effective, less toxic treatments for invasive breast cancer. Indole-3-carbinol is a phytochemical found in cruciferous vegetables and one of its major metabolites, 3,3’-diindolylmethane (DIM), exhibits a broad range of anticancer and antitumorigenic activities. ER-negative MDA-MB-231 and MDA-MB-453 breast cancer cell growth was inhibited after treatment with a novel series of methylenesubstituted DIMs (C-DIMs), namely 1,1-bis(3’-indolyl)-1-(p-substitutedphenyl) methanes containing trifluoromethyl (DIM-C-pPhCF3), t-butyl (DIM-C-pPhtBu) and phenyl (DIM-C-pPhC6H5) groups. In addition, DIM-C-pPhC6H5 (40 mg/kg/d) inhibited tumor growth in nude mice bearing MDA-MB-231 cells as xenografts. Treatment of breast cancer cells with C-DIMs lead to downregulation of cyclin D1 and induction of non-steroidal anti-inflammatory drug-activated gene 1. Detection of necrosis, caspasedependent or caspase-independent apoptosis were not observed in breast cancer cells treated with C-DIMs, however autophagic cell death was induced by C-DIMs. DIM and ring-substituted DIMs have exhibited antitumorigenic activity in tumor murine mammary models. An investigation into the mechanism of cell death induced by DIM and 5,5’-dibromoDIM (5,5’-diBrDIM) in both ER-positive (MCF-7) and ERnegative (MDA-MB-231) breast cancer cells revealed modulation of several key signaling pathways involved in growth control. Both DIM and 5,5’-diBrDIM downregulated cyclin D1, although only 5,5’-diBrDIM induced a depolarization of the mitochondrial membrane. In addition, apoptosis was observed in MCF-7 cells treated with 5,5’-diBrDIM but not MDA-MB-231 cells. In summary, C-DIMs may represent new mechanism-based agents for treatment of breast cancer through induction of autophagic cell death. The ring-substituted DIMs correspond to a novel class of uncharged mitochondrial poisons that are also highly effective in inhibiting breast cancer cell growth. Results of this research provide evidence for the potential role of two new series of DIM analogs for the treatment of highly aggressive breast cancer

1,1-Bis(3'-indolyl)-1-(<it>p</it>-substituted phenyl)methanes induce autophagic cell death in estrogen receptor negative breast cancer

Abstract Background A novel series of methylene-substituted DIMs (C-DIMs), namely 1,1-bis(3'-indolyl)-1-(p-substituted phenyl)methanes containing t-butyl (DIM-C-pPhtBu) and phenyl (DIM-C-pPhC6H5) groups inhibit proliferation of invasive estrogen receptor-negative MDA-MB-231 and MDA-MB-453 human breast cancer cell lines with IC50 values between 1-5 uM. The main purpose of this study was to investigate the pathways of C-DIM-induced cell death. Methods The effects of the C-DIMs on apoptotic, necrotic and autophagic cell death were determined using caspase inhibitors, measurement of lactate dehydrogenase release, and several markers of autophagy including Beclin and light chain associated protein 3 expression (LC3). Results The C-DIM compounds did not induce apoptosis and only DIM-C-pPhCF3 exhibited necrotic effects. However, treatment of MDA-MB-231 and MDA-MB-453 cells with C-DIMs resulted in accumulation of LC3-II compared to LC3-I protein, a characteristic marker of autophagy, and transient transfection of green fluorescent protein-LC3 also revealed that treatment with C-DIMs induced a redistribution of LC3 to autophagosomes after C-DIM treatment. In addition, the autofluorescent drug monodansylcadaverine (MDC), a specific autophagolysosome marker, accumulated in vacuoles after C-DIM treatment, and western blot analysis of lysates from cells treated with C-DIMs showed that the Beclin 1/Bcl-2 protein ratio increased. Conclusion The results suggest that C-DIM compounds may represent a new mechanism-based agent for treating drug-resistant ER-negative breast tumors through induction of autophagy.</p

One year treatment with salmeterol compared with beclomethasone in children with asthma

The aim of this study was to compare the effects of salmeterol and beclomethasone on lung function and symptoms in children with mild to moderate asthma. Sixty-seven children not treated with inhaled corticosteroids were randomized in a double-blind parallel study either to salmeterol 50 mu g b.i.d. or beclomethasone 200 mu g b.i.d. After one year, FEV1 significantly increased in the beclomethasone group, whereas in the salmeterol group there was a small reduction. Differences between groups were 14.2% predicted (p <0.0001) and 7.0% predicted (p = 0.007) for pre-and postbronchodilator FEV1 values, respectively. PD20 methacholine decreased by 0.73 DD (p = 0.05) in the salmeterol group and increased by 2.02 DD (p <0.0001) in the beclomethasone group. Morning and evening PEF and symptom scores improved in both groups, although more in the beclomethasone group. Asthma exacerbations, for which prednisolone was needed, were more frequent in the salmeterol group (17 versus two), as were the number of withdrawals due to exacerbations (six versus one). However, growth was significantly slower in the beclomethasone group (-0.28 SDS) compared with that in the salmeterol group (-0.03 SDS) (p = 0.001). We conclude that treatment with a moderate dose of beclomethasone is superior to salmeterol in children with mild to moderate asthma and recommend that salmeterol should not be used as monotherapy