bafilomycin-a and pepstatin

Although several ADAMs (A disintegrin-like and metalloproteases) have been shown to contribute to the amyloid precursor protein (APP) metabolism, the full spectrum of metalloproteases involved in this metabolism remains to be established. Transcriptomic analyses centred on metalloprotease genes unraveled a 50% decrease in ADAM30 expression that inversely correlates with amyloid load in Alzheimer's disease brains. Accordingly, in vitro down- or up-regulation of ADAM30 expression triggered an increase/decrease in Aβ peptides levels whereas expression of a biologically inactive ADAM30 (ADAM30(mut)) did not affect Aβ secretion. Proteomics/cell-based experiments showed that ADAM30-dependent regulation of APP metabolism required both cathepsin D (CTSD) activation and APP sorting to lysosomes. Accordingly, in Alzheimer-like transgenic mice, neuronal ADAM30 over-expression lowered Aβ42 secretion in neuron primary cultures, soluble Aβ42 and amyloid plaque load levels in the brain and concomitantly enhanced CTSD activity and finally rescued long term potentiation alterations. Our data thus indicate that lowering ADAM30 expression may favor Aβ production, thereby contributing to Alzheimer's disease development.

Topics: ADAM Proteins; Alzheimer Disease; Amino Acid Sequence; Amyloid beta-Peptides; Animals; Brain; Cathepsin D; Cell Line, Tumor; Down-Regulation; HEK293 Cells; Humans; Lysosomes; Macrolides; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Fluorescence; Patch-Clamp Techniques; Pepstatins; RNA Interference; RNA, Small Interfering

Pemetrexed, a multitarget antifolate used to treat malignant mesothelioma and non-small cell lung cancer (NSCLC), has been shown to stimulate autophagy. In this study, we determined whether autophagy could be induced by pemetrexed and simvastatin cotreatment in malignant mesothelioma and NSCLC cells. Furthermore, we determined whether inhibition of autophagy drives apoptosis in malignant mesothelioma and NSCLC cells. Malignant mesothelioma MSTO-211H and A549 NSCLC cells were treated with pemetrexed and simvastatin alone and in combination to evaluate their effect on autophagy and apoptosis. Cotreatment with pemetrexed and simvastatin induced greater caspase-dependent apoptosis and autophagy than either drug alone in malignant mesothelioma and NSCLC cells. 3-Methyladenine (3-MA), ATG5 siRNA, bafilomycin A, and E64D/pepstatin A enhanced the apoptotic potential of pemetrexed and simvastatin, whereas rapamycin and LY294002 attenuated their induction of caspase-dependent apoptosis. Our data indicate that pemetrexed and simvastatin cotreatment augmented apoptosis and autophagy in malignant mesothelioma and NSCLC cells. Inhibition of pemetrexed and simvastatin-induced autophagy was shown to enhance apoptosis, suggesting that this could be a novel therapeutic strategy against malignant mesothelioma and NSCLC.

Topics: Adenine; AMP-Activated Protein Kinases; Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Autophagy; Autophagy-Related Protein 5; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Drug Synergism; Humans; Lung Neoplasms; Macrolides; Mesothelioma; Mesothelioma, Malignant; Mice, Nude; Microtubule-Associated Proteins; Pemetrexed; Pepstatins; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; RNA Interference; Signal Transduction; Simvastatin; Time Factors; TOR Serine-Threonine Kinases; Transfection; Tumor Burden; Xenograft Model Antitumor Assays

The best characterized survival mechanism of Mycobacterium tuberculosis inside the macrophage is the inhibition of phagosomal maturation. Phagosomal maturation involves several steps including fusion with lysosomes and acidification. However, it has not been elucidated which components of phagosomal maturation correlate with growth restriction of virulent mycobacteria in human macrophages, and we aimed to study this. We infected human monocyte-derived macrophages with M. tuberculosis and assessed bacterial replication, translocation of CD63 to the phagosome, and phagosomal acidification. We found that unstimulated human macrophages were able to control infection with M. tuberculosis upon inoculation at a low multiplicity of infection (MOI) of 1, but not at a high MOI of 10. The low MOI resulted in a macrophage-controlled balance between host cells and bacteria. Both H37Rv and H37Ra infection, at high and low MOI, led to equally ineffective translocation of CD63 to the phagosome. On the other hand, acidification of mycobacterial phagosomes was more efficient at MOI 1 than 10 with both mycobacterial strains, consistent with a direct or indirect role for phagosomal acidification in restricting M. tuberculosis growth. Furthermore, inhibition of the vacuolar H(+)-ATPase as well as of cathepsin D led to enhanced mycobacterial replication inside the macrophage. This again shows the importance of phagosomal acidification for control of mycobacterial growth, through the activation of lysosomal hydrolases. We conclude that acidification and related functional aspects of the mature phagosome are important factors for restriction of M. tuberculosis replication in human macrophages.

Topics: Adenosine Triphosphatases; Cathepsin D; Cell Growth Processes; Cells, Cultured; DNA Replication; DNA, Bacterial; Humans; Macrolides; Macrophages; Mycobacterium tuberculosis; Pepstatins; Phagosomes; Protein Transport; Tetraspanin 30; Tuberculosis