Apoptosis/drug effects; Boronic Acids/pharmacology; Multiple Myeloma/pathology; Protease Inhibitors/pharmacology; Pyrazines/pharmacology; Stromal Cells/drug effects; TNF-Related Apoptosis-Inducing Ligand/physiology; Boronic Acids/therapeutic use; Bortezomib; CASP8 and FADD-Like Apoptosis Regulating Protein/antagonists & inhibitors; Cell Line, Tumor/drug effects; Cells, Cultured/drug effects; Cells, Cultured/metabolism; Coculture Techniques; Cytokines/biosynthesis; Cytokines/genetics; Drug Screening Assays, Antitumor; Drug Synergism; Gene Expression Regulation, Neoplastic/drug effects; Humans; Neoplasm Proteins/antagonists & inhibitors; Neoplasm Proteins/biosynthesis; Neoplasm Proteins/genetics; Protease Inhibitors/therapeutic use; Pyrazines/therapeutic use; Receptors, TNF-Related Apoptosis-Inducing Ligand/antagonists & inhibitors; Receptors, TNF-Related Apoptosis-Inducing Ligand/physiology; Receptors, Tumor Necrosis Factor/antagonists & inhibitors; Receptors, Tumor Necrosis Factor/physiology; Recombinant Proteins/pharmacology; Stromal Cells/metabolism; TNF-Related Apoptosis-Inducing Ligand/pharmacology; Tumor Escape/drug effects