Carfilzomib is an epoxomicin derivate with potential antineoplastic activity. Kyprolis (carfilzomib's trade name) is a proteasome inhibitor that is indicated for the treatment of patients with relapsed or refractory multiple myeloma who have received one or more lines of therapy as a single agent or in combination with dexamethasone or with lenalidomide plus dexamethasone. Carfilzomib is made up of four modified peptides. It irreversibly and selectively binds to N-terminal threonine-containing active sites of the 20S proteasome, the proteolytic core particle within the 26S proteasome. This 20S core has 3 catalytic active sites: the chymotrypsin, trypsin, and caspase-like sites. Inhibition of the chymotrypsin-like site by carfilzomib (β5 and β5i subunits) is the most effective target in decreasing cellular proliferation, ultimately resulting in cell cycle arrest and apoptosis of cancerous cells. At higher doses, carfilzomib will inhibit the trypsin-and capase-like sites. Inhibition of proteasome-mediated proteolysis results in an accumulation of polyubiquinated proteins, which may lead to cell cycle arrest, induction of apoptosis, and inhibition of tumor growth.

Bortezomib is the therapeutic proteasome inhibitor. First, which is tested in humans. The boron atom in bortezomib binds the catalytic site of the 26S proteasome with high affinity and specificity. Bortezomib is approved in the U.S. for treating relapsed multiple myeloma and mantle cell lymphoma. The 26S proteasome degrades various proteins critical to cancer cell survival, such as cyclins, tumor suppressors, BCL-2, and cyclin-dependent kinase inhibitors. Inhibition of these degradations sensitizes cells to apoptosis. Bortezomib is a potent inhibitor of 26S proteasome, which sensitizes activity in dividing multiple myeloma and leukemic cells, thus inducing apoptosis. Most commonly reported adverse reactions (incidence ≥30%) in clinical studies include asthenic conditions, diarrhea, nausea, constipation, peripheral neuropathy, vomiting, pyrexia, thrombocytopenia, psychiatric disorders, anorexia and decreased appetite, neutropenia, neuralgia, leukopenia and anemia. Co-administration of ketoconazole, a potent CYP3A inhibitor, increased the exposure of bortezomib. Co-administration of melphalan-prednisone increased the exposure of bortezomib. However, this increase is unlikely to be clinically relevant.

Pristimerin, the methyl ester of celasterol, is a triterpenoid quinone methide isolated from Pristimerae indica. Pristimerin shows anticancer activity in vitro towards myeloma, prostate, breast, ovarian cancer cell lines and inhibits xenografted plasmacytoma tumors in mice. In a rat model of adjuvant arthritis, pristimerin effectively inhibited both arthritic inflammation and cartilage and bone damage in the joints. Pristimerin acts by inhibiting NF-kB signaling pathway and the 26S proteasome.

Celastrol is a pentacyclic triterpenoid isolated from the root extracts of Tripterygium wilfordii, a perrennial creeping plant indigenous to large area in Southern China. Celastrol possess antioxidant and anti-inflammatory and anticancer action. In the mouse model of rheumatoid arthritis it reduced inflammatory swelling, suppressed humoral and skin response and reduced pathological progression of joint. Celastrol demonstrated efficacy in transgenic mouse model of amyotrophic lateral sclerosis. Anticancer activity of celastrol was shown in xenograft models of prostate cancer. Celastrol suppresses food intake, blocks reduction of energy expenditure, and leads to up to 45% weight loss in hyperleptinemic diet-induced obese (DIO) mice by increasing leptin sensitivity. Celastrol acts by interfering with the activity of Hsp90, IKK-beta and proteasome S26 subunit.

Gambogic acid (GA), a naturally occurring xanthone-based moiety, reported from Garcinia hanburyi tree, is known to perform numerous intracellular and extracellular actions, including programmed cell death, autophagy, cell cycle arrest, antiangiogenesis, antimetastatic, and anti-inflammatory activities. In addition, GA-based synergistic approaches have been proven to enhance the healing strength of existing chemotherapeutic agents along with lesser side effects. Among cellular targets of gambogic acid topoisomerase, multidrug-resistant protein ATP-binding cassette transporter B1 (ABCB1) and Transferrin receptor.

Bortezomib is the therapeutic proteasome inhibitor. First, which is tested in humans. The boron atom in bortezomib binds the catalytic site of the 26S proteasome with high affinity and specificity. Bortezomib is approved in the U.S. for treating relapsed multiple myeloma and mantle cell lymphoma. The 26S proteasome degrades various proteins critical to cancer cell survival, such as cyclins, tumor suppressors, BCL-2, and cyclin-dependent kinase inhibitors. Inhibition of these degradations sensitizes cells to apoptosis. Bortezomib is a potent inhibitor of 26S proteasome, which sensitizes activity in dividing multiple myeloma and leukemic cells, thus inducing apoptosis. Most commonly reported adverse reactions (incidence ≥30%) in clinical studies include asthenic conditions, diarrhea, nausea, constipation, peripheral neuropathy, vomiting, pyrexia, thrombocytopenia, psychiatric disorders, anorexia and decreased appetite, neutropenia, neuralgia, leukopenia and anemia. Co-administration of ketoconazole, a potent CYP3A inhibitor, increased the exposure of bortezomib. Co-administration of melphalan-prednisone increased the exposure of bortezomib. However, this increase is unlikely to be clinically relevant.

Bortezomib is the therapeutic proteasome inhibitor. First, which is tested in humans. The boron atom in bortezomib binds the catalytic site of the 26S proteasome with high affinity and specificity. Bortezomib is approved in the U.S. for treating relapsed multiple myeloma and mantle cell lymphoma. The 26S proteasome degrades various proteins critical to cancer cell survival, such as cyclins, tumor suppressors, BCL-2, and cyclin-dependent kinase inhibitors. Inhibition of these degradations sensitizes cells to apoptosis. Bortezomib is a potent inhibitor of 26S proteasome, which sensitizes activity in dividing multiple myeloma and leukemic cells, thus inducing apoptosis. Most commonly reported adverse reactions (incidence ≥30%) in clinical studies include asthenic conditions, diarrhea, nausea, constipation, peripheral neuropathy, vomiting, pyrexia, thrombocytopenia, psychiatric disorders, anorexia and decreased appetite, neutropenia, neuralgia, leukopenia and anemia. Co-administration of ketoconazole, a potent CYP3A inhibitor, increased the exposure of bortezomib. Co-administration of melphalan-prednisone increased the exposure of bortezomib. However, this increase is unlikely to be clinically relevant.