MG132

MG-132 displays >1000 times more activity than ZLLal in inhibiting the ZLLL-MCA-degrading activity of 20S proteasome with IC50 of 100 nM versus 110 μM. This compound also inhibits calpain with IC50 of 1.2 μM. This chemical induces neurite outgrowth in PC12 cells at an optimal concentration of 20 nM, displaying 500 times more potency than ZLLal. [1] This compound (10 μM) potently inhibits TNF-α-induced NF-κB activation, interleukin-8 (IL-8) gene transcription, and IL-8 protein release in A549 cells by inhibition of proteasome-mediated IκBα degradation. [2] This chemical treatment potently induces p53-dependent apoptosis in KIM-2 cells by 26S proteasome inhibition. [3] Unlike BzLLLCOCHO or PS-341, this compound treatment results in weak inhibition of the chymotrypsinlike (CT-L) and peptidylglutamyl peptide hydrolysing (PGPH) activities of the 26S proteasome, whereas multiple myeloma cells (U266 and OPM-2) are more sensitive to induction of apoptosis by this chemical than BzLLLCOCHO. [4] This compound (1 μM) sensitizes TRAIL-resistant prostate cancer cells by activating the AP-1 family members c-Fos and c-Jun, which, in turn, repress the antiapoptotic molecule c-FLIP(L). [5] This chemical significantly enhances the ability of inositol hexakisphosphate (IP6) to reduce cellular metabolic activity in both PC3 and DU145 androgen-independent prostate cancer (AIPCa) cell lines. [6]

Administration of MG-132 effectively rescues the expression levels and plasma membrane localization of dystrophin, β-dystroglycan, α-bdystroglycan, and α-sarcoglycan in skeletal muscle fibers from mdx mice, reduces muscle membrane damage, and ameliorates the histopathological signs of muscular dystrophy. [7] Treatment with this compound significantly reduces immobilization-induced skeletal muscle atrophy in mice, by downregulating the muscle-specific ubiquitin ligases atrogin-1/MAFbx and MuRF-1 mRNA. [8]

• Medición de las actividades inhibitorias de MG-132 contra el proteasome 20S

  La mezcla de reacción para el ensayo de inhibición del proteasome 20S contiene 0,1 M Tris-acetato, pH 7,0, proteasome 20S, MG-132 y 25 μM de sustrato disuelto en dimetilsulfóxido en un volumen final de 1 mL. Después de la incubación a 37 °C durante 15 minutos, la reacción se detiene mediante la adición de 0,1 mL de SDS al 10% y 0,9 mL de Tris acetato 0,1 M, pH 9,0. Se mide la fluorescencia de los productos de reacción. Para determinar la IC50 contra el proteasome 20S, se incluyen varias concentraciones de este compuesto en la mezcla de ensayo.

• Líneas celulares

  KIM-2, HC11, and ES

• Concentraciones

  Dissolved in DMSO, final concentrations ~25 μM

• Tiempo de incubación

  24 and 48 hours

• Método

  Cells are exposed to various concentrations of MG-132 for 24, and 48 hours. Supernatant and monolayer cells are harvested by centrifugation and fixed in 70% ethanol in PBS for staining with acridine orange. Equal volumes of cells and acridine orange (5 mg/mL in PBS) are mixed on a microscope slide and examined by fluorescence microscopy. For annexin V analysis, cells are harvested by centrifugation and stained with annexin V and propidium iodide. For cell cycle analysis, cells are rehydrated in PBS at room temperature for 10 minutes, followed by staining with propidium iodide (5 mg/mL). All samples are analyzed using a Coulter Epics XL flow cytometer.

• Modelos animales

  Male mdx (C57BL/10ScSn DMD mdx) mice

• Dosificaciones

  ~10 μg/kg/day

• Administración

  Injection