MLN9708

MLN9708, also known as ixazomib, is a second-generation small-molecule proteasome inhibitor. It is a citrate ester that immediately hydrolyzes to its biologically active form MLN2238 upon exposure to aqueous solutions or plasma. MLN9708 was selected from a large pool of boron-containing proteasome inhibitors based on a physicochemical profile that was distinct from bortezomib. MLN9708 has a shorter 20S proteasome dissociation half-life than bortezomib, which is demonstrated to play an important role in its improved tissue distribution.

Reference

Erik Kupperman, Edmund C. Lee, Yueying Cao, Bret Bannerman, Michael Fitzgerald, Allison Berger, Jie Yu, Yu Yang, Paul Hales, Frank Bruzzese, Jane Liu, Jonathan Blank, Khristofer Garcia, Christopher Tsu, Larry Dick, Paul Fleming, Li Yu, Mark Manfredi, Mark Rolfe, and Joe Bolen. Evaluation of the Proteasome Inhibitor MLN9708 in Preclinical Models of Human Cancer. Cancer Res March 1, 2010 70; 1970.

Edmund C. Lee, Michael Fitzgerald, Bret Bannerman, Jill Donelan, Kristen Bano, Jennifer Terkelsen, Daniel P. Bradley, Ozlem Subakan, Matthew D. Silva, Ray Liu, Michael Pickard, Zhi Li, Olga Tayber, Ping Li, Paul Hales, Mary Carsillo, Vishala T. Neppalli, Allison J. Berger, Erik Kupperman, Mark Manfredi, Joseph B. Bolen, Brian Van Ness, Siegfried Janz. Antitumor Activity of the Investigational Proteasome Inhibitor MLN9708 in Mouse Models of B-cell and Plasma Cell Malignancies. Clin Cancer Res December 1, 2011 17; 7313.

A New Perspective for Osteosarcoma Therapy: Proteasome Inhibition by MLN9708/2238 Successfully Induces Apoptosis and Cell Cycle Arrest and Attenuates the Invasion Ability of Osteosarcoma Cells in Vitro.[Pubmed:28214890]

Cell Physiol Biochem. 2017;41(2):451-465.

BACKGROUND: The proteasome exists in all eukaryotic cells and provides the main route of intracellular proteins degradation involved in cell growth and apoptosis. Proteasome inhibition could block protein degradation pathways and disturb regulatory networks, possibly leading to profound effects on cell growth, particularly in cancer cells. A proteasome inhibitor with an appropriate toxicity index for malignant cells rather than normal cells would be an attractive anticancer therapy. METHODS: The human osteosarcoma (OS) cell lines MG-63 and Saos-2 and normal osteoblast cells were used to study the antitumour activity of the proteasome inhibitor MLN9708/2238. RESULTS: MLN2238 inhibited cell growth, induced cell cycle arrest and apoptosis, and attenuated the invasion abilities of MG-63 and Saos-2 cells, with little cytotoxicity to normal cells. In addition, MLN2238 promoted antitumour mechanisms including the accumulation of E2F1, P53, P21 and other negative G2/M checkpoint proteins; up-regulated the relative expression ratio of BAX/BCL-2, APAF-1 and pro-apoptotic proteins of the BCL-2 family; triggered mitochondrial outer membrane permeabilization (MOMP); down-regulated BCL-2 and XIAP; activated caspase3/8/9; and suppressed MMP2/9 expression and secretion levels. CONCLUSIONS: The proteasome may be a novel biochemical target for OS treatment in vitro. Our study provides a promising mechanistic framework for MLN9708/2238 in OS treatment, supporting its clinical development.

Next-generation proteasome inhibitor MLN9708 sensitizes breast cancer cells to doxorubicin-induced apoptosis.[Pubmed:27217076]

Sci Rep. 2016 May 24;6:26456.

Doxorubicin (Dox), one of the most effective chemotherapy drug for cancer treatment, is limited by its severe side effects and chemoresistance. Dox induces DNA damage and leads to significant proteomic changes in the cancer cells, which makes the ubiquitin-proteasome system a potential target to enhance the efficacy of Dox therapy. The unsuccessful clinical trials of proteasome inhibitor PS-341 (bortezomib) in solid tumors led to the invention of MLN9708 (ixazomib), an orally bioavailable next-generation proteasome inhibitor with improved pharmacokinetic and pharmacodynamic features. In this preclinical study, we used eight human breast cancer cell lines, which represent the major molecular subtypes of breast cancer, to validate the cytotoxic effects of MLN9708, alone and in combination with Dox. We found that MLN9708 had cytotoxic effects, induced autophagy and MKP-1 expression, and enhanced Dox-induced apoptosis in these cell lines. MLN9708 also enhanced Dox-induced JNK and p38 phosphorylation and inhibited Dox-induced IkappaBalpha degradation. Our in vitro results suggest that MLN9708 has antitumor effects in breast cancer and can sensitize breast cancer cells to Dox treatment. This promising combination may be an effective and feasible therapeutic option for treating breast cancer and warrants clinical validation.

Ultra high performance liquid chromatography coupled with high resolution quantitation mass spectrometry method development and validation for determining genotoxic 2,5-dichlorobenzoyl chloride in MLN9708 drug substance.[Pubmed:24309557]

J Pharm Biomed Anal. 2014 Feb;89:233-9.

A novel reversed-phase ultra high performance liquid chromatography coupled with high resolution quantitation mass spectrometry (UHPLC/HRQMS) method was developed to quantify 2,5-dichlorobenzoyl chloride (DCBC), a genotoxic impurity, in MLN9708 drug substance. A surrogate strategy was utilized whereby DCBC was intentionally hydrolyzed to 2,5-dichlorobenzoic acid (DCBA) to provide a stable and reliable detection target. The hydrolysis approach was conservative since the measured signal represented the sum of DCBC and DCBA in MLN9708 drug substance, and such approach was acknowledged and accepted by food and drug administration (FDA). HRQMS was used as the detection method since conventional MS/MS methodology gave poor sensitivity and selectivity due to non-specific fragmentation of carbon dioxide loss upon collision activation dissociation. Profile algorithm mass spectrometry data were acquired with mass resolving power (MRP) of 60,000. Quantitation was based on the extracted ion chromatography (EIC) peak area signal, which was extracted at m/z 188.9515 with a mass extraction window (MEW) of 5ppm. The UHPLC/HRQMS method was validated based on International Conference on Harmonization (ICH) guidelines, which included selectivity, limit of detection (LOD), limit of quantitation (LOQ), repeatability, linearity, accuracy, and stability.

Preclinical activity of the oral proteasome inhibitor MLN9708 in Myeloma bone disease.[Pubmed:24486586]

Clin Cancer Res. 2014 Mar 15;20(6):1542-54.

PURPOSE: MLN9708 (ixazomib citrate), which hydrolyzes to pharmacologically active MLN2238 (ixazomib), is a next-generation proteasome inhibitor with demonstrated preclinical and clinical antimyeloma activity, but yet with an unknown effect on myeloma bone disease. Here, we investigated its bone anabolic and antiresorptive effects in the myeloma setting and in comparison with bortezomib in preclinical models. EXPERIMENTAL DESIGN: The in vitro effect of MLN2238 was tested on osteoclasts and osteoclast precursors from healthy donors and patients with myeloma, and on osteoprogenitors derived from bone marrow mesenchymal stem cells also from both origins. We used an in vivo model of bone marrow-disseminated human myeloma to evaluate MLN2238 antimyeloma and bone activities. RESULTS: Clinically achievable concentrations of MLN2238 markedly inhibited in vitro osteoclastogenesis and osteoclast resorption; these effects involved blockade of RANKL (receptor activator of NF-kappaB ligand)-induced NF-kappaB activation, F-actin ring disruption, and diminished expression of alphaVbeta3 integrin. A similar range of MLN2238 concentrations promoted in vitro osteoblastogenesis and osteoblast activity (even in osteoprogenitors from patients with myeloma), partly mediated by activation of TCF/beta-catenin signaling and upregulation of the IRE1 component of the unfolded protein response. In a mouse model of bone marrow-disseminated human multiple myeloma, orally administered MLN2238 was equally effective as bortezomib to control tumor burden and also provided a marked benefit in associated bone disease (sustained by both bone anabolic and anticatabolic activities). CONCLUSION: Given favorable data on pharmacologic properties and emerging clinical safety profile of MLN9708, it is conceivable that this proteasome inhibitor may achieve bone beneficial effects in addition to its antimyeloma activity in patients with myeloma.