Marcus Koppitz

Novel Mps1 Kinase Inhibitors with Potent Antitumor Activity.

Monopolar spindle 1 (Mps1) has been shown to function as the key kinase that activates the spindle assembly checkpoint (SAC) to secure proper distribution of chromosomes to daughter cells. Here, we report the structure and functional characterization of two novel selective Mps1 inhibitors, BAY 1161909 and BAY 1217389, derived from structurally distinct chemical classes. BAY 1161909 and BAY 1217389 inhibited Mps1 kinase activity with IC50 values below 10 nmol/L while showing an excellent selectivity profile. In cellular mechanistic assays, both Mps1 inhibitors abrogated nocodazole-induced SAC activity and induced premature exit from mitosis (“mitotic breakthrough”), resulting in multinuclearity and tumor cell death. Both compounds efficiently inhibited tumor cell proliferation in vitro (IC50 nmol/L range). In vivo, BAY 1161909 and BAY 1217389 achieved moderate efficacy in monotherapy in tumor xenograft studies. However, in line with its unique mode of action, when combined with paclitaxel, low doses of Mps1 inhibitor reduced paclitaxel-induced mitotic arrest by the weakening of SAC activity. As a result, combination therapy strongly improved efficacy over paclitaxel or Mps1 inhibitor monotreatment at the respective MTDs in a broad range of xenograft models, including those showing acquired or intrinsic paclitaxel resistance. Both Mps1 inhibitors showed good tolerability without adding toxicity to paclitaxel monotherapy. These preclinical findings validate the innovative concept of SAC abrogation for cancer therapy and justify clinical proof-of-concept studies evaluating the Mps1 inhibitors BAY 1161909 and BAY 1217389 in combination with antimitotic cancer drugs to enhance their efficacy and potentially overcome resistance. Mol Cancer Ther; 15(4); 583–92. ©2016 AACR.

Abstract 3090: Novel Mps1 kinase inhibitors with potent anti-tumor activity

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA Cell cycle deregulation represents one of the hallmarks of cancer and consequently cell cycle arrest is the predominant mode of action for a number of antimitotic cancer drugs (e.g. taxanes and vinca alkaloids). Targeted disruption of the cell cycle checkpoint offers a novel approach to cancer treatment since tumor cells will not arrest in mitosis despite DNA damage or unattached/misattached chromosomes resulting in aneuploidy and cell death. Mps1, a mitotic kinase that is overexpressed in several human cancers, has been shown to function as the key kinase which activates the spindle assembly checkpoint (SAC) to secure proper distribution of chromosomes to daughter cells. Here, we disclose for the first time the structure and functional characterization of two novel Mps1 inhibitors, BAY 1161909 and BAY 1217389, derived from structurally distinct chemical classes. BAY 1161909 and BAY 1217389 inhibited Mps1 kinase activity with IC50 values below 10 nM while showing an excellent selectivity profile against a broad panel of kinases. In cellular mechanistic assays, BAY 1161909 and BAY 1217389 abrogated nocodazole-induced SAC activity, inducing premature exit from mitosis (“mitotic breakthrough”), which results in multinuclearity and tumor cell death. Both compounds efficiently inhibited tumor cell proliferation in vitro (IC50 values in low nanomolar range), showing a similar inhibitory pattern in a broad panel of tumor cell lines. In vivo, the Mps1 inhibitors BAY 1161909 and BAY 1217389 achieved moderate efficacy in monotherapy in tumor xenograft studies (tumor growth inhibition ∼ 50%). However, according to its unique mode of action, when combined with paclitaxel, at the maximum tolerated dose, low doses of Mps1 inhibitor reduced paclitaxel-induced mitotic arrest in line with weakening of SAC activity. Consequently, combination therapy strongly improved efficacy over paclitaxel or Mps1 inhibitor mono-treatment in a broad range of xenograft models including those being intrinsically paclitaxel-insensitive as well as those with acquired paclitaxel resistance. Both Mps1 inhibitors showed good tolerability without adding toxicity to paclitaxel monotherapy. Our findings validate the innovative concept of SAC abrogation and justify clinical proof of concept studies evaluating Mps1 inhibitors BAY 1161909 and BAY 1217389 in combination with antimitotic cancer drugs in order to enhance their efficacy and potentially overcome resistance. BAY 1161909 is currently in a phase I clinical trial ([NCT02138812][1]), start of clinical investigation of BAY 1217389 is planned. To our knowledge BAY 1161909 and BAY 1217389 are the first Mps1 inhibitors in clinical trials. Citation Format: Antje Margret Wengner, Gerhard Siemeister, Marcus Koppitz, Volker Schulze, Dirk Kosemund, Ulrich Klar, Detlef Stoeckigt, Roland Neuhaus, Philip Lienau, Benjamin Bader, Stefan Prechtl, Olaf Doehr, Marian Raschke, Oliver von Ahsen, Cem Elbi, Ingmar Bruns, Martin Michels, Bertolt Kreft, Franz von Nussbaum, Michael Brands, Dominik Mumberg, Karl Ziegelbauer. Novel Mps1 kinase inhibitors with potent anti-tumor activity. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3090. doi:10.1158/1538-7445.AM2015-3090 [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT02138812&atom=%2Fcanres%2F75%2F15_Supplement%2F3090.atom

Abstract 4540: SAC abrogation by MPS1 kinase inhibition: preclinical proof of concept of a novel approach to tumor treatment

Cell cycle deregulation represents one of the classical hallmarks of cancer and consequently cell cycle arrest is the predominant mode of action of a number of antimitotic cancer drugs (e.g. taxanes and vinca alkaloids). Targeted disruption of the cell cycle checkpoint offers a novel approach to cancer treatment: driving tumor cells into cell division despite DNA damage or unattached/misattached chromosomes resulting in a lethal degree of DNA damage or aneuploidy. MPS1, a mitotic kinase that is overexpressed in several human cancers, has been shown to function as the key kinase which activates the spindle assembly checkpoint (SAC) to secure proper distribution of chromosomes to daughter cells. Here, we report the identification and functional characterization of novel inhibitors of MPS1 from two structurally unrelated chemical classes. In biochemical assays, these molecules inhibited the kinase activity of MPS1 with IC50 values in the single digit nanomolar range and have shown an exquisite selectivity against a panel of kinases. In cellular assays the compounds were able to abrogate nocodazole-induced SAC, to reduce time in mitosis, to induce multinuclearity and apoptotic cell death, and to inhibit tumor cell proliferation with IC50 values in the low nanomolar range. In combination experiments MPS1 inhibitors showed cooperativity with low concentrations of paclitaxel. MPS1 inhibitors showed limited efficacy in monotherapy (T/C ca. 0.6) in tumor xenograft studies. However, when combined with paclitaxel dosed at the maximal tolerated dose, low doses of MPS1 inhibitor strongly improved efficacy over paclitaxel or MPS inhibitor monotreatment in intrinsically paclitaxel-insensitive xenograft models. The combination treatment was well tolerated. These results validate the concept of SAC abrogation preclinically and pave the way to a clinical proof of concept. Citation Format: Dominik Mumberg, Gerhard Siemeister, Antje M. Wengner, Marcus Koppitz, Volker Schulze, Benjamin Bader, Stefan Prechtl, Bertolt Kreft, Karl Ziegelbauer. SAC abrogation by MPS1 kinase inhibition: preclinical proof of concept of a novel approach to tumor treatment. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4540. doi:10.1158/1538-7445.AM2014-4540

Abstract 706: Novel MPS1 inhibitors with potential anticancer activity.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC MPS1, a mitotic kinase that is overexpressed in several human cancers, has been shown to contribute to the alignment of chromosomes to the metaphase plate, as well as to the execution of the spindle assembly checkpoint (SAC). Here, we report the identification and functional characterization of three novel inhibitors of MPS1 from two structurally independent chemical classes, Mps-BAY1, Mps-BAY2a and Mps-BAY2b. In biochemical assays, these molecules inhibited the kinase activity of MPS1 with IC50 values in the low nanomolar range. By selectively inactivating MPS1, these small molecule inhibitors can arrest the proliferation of cancer cells, causing their polyploidization and/or cell death. Cancer cells treated with Mps-BAY1 or Mps-BAY2a manifested multiple signs of mitotic perturbation including inefficient chromosomal congression during metaphase, unscheduled SAC inactivation, and severe anaphase defects. Videomicroscopic cell fate profiling of GFP-histone 2B-expressing cells revealed the capacity of MPS1 inhibitors to subvert mitotic timing by inducing a premature anaphase entry in the context of misaligned metaphase plates. Hence, in the presence of MPS1 inhibitors, cells either divided in a bipolar (but often asymmetric) fashion or entered one or more rounds of abortive mitosis, generating gross aneuploidy and polyploidy, respectively. In both cases, cells ultimately succumbed from the mitotic catastrophe-induced activation of the intrinsic pathway of apoptosis. Of note, MPS1 inhibitors and paclitaxel (a microtubular poison) combined at low doses synergized at increasing the frequency of chromosome misalignments and missegregations in the context of SAC inactivation. This resulted in massive polyploidization, followed by the activation of mitotic catastrophe. A more than additive interaction between paclitaxel and MPS1 inhibitors could also be demonstrated in vivo in a HeLa-Matu human cervical xenograft model. The combination of these agents reduced the mitotic index in xenograft tumors and exerted superior antineoplastic effects (T/C 0.04) as compared to the administration of vehicle, as well as paclitaxel (T/C 0.38) or MPS inhibitor (T/C 0.51) alone. Altogether, these results suggest that MPS1 inhibitors may have potent anticancer activity, either as standalone agents or in combination with microtubule-targeting agents. Citation Format: Antje Wengner, Mohamed Jemaa, Lorenzo Galluzzi, Oliver Kepp, Michael Brands, Marcus Koppitz, Volker Schulze, Gerhard Siemeister, Dominik Mumberg, Karl Ziegelbauer, Maria Castedo, Ilio Vitale, Guido Kroemer. Novel MPS1 inhibitors with potential anticancer activity. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 706. doi:10.1158/1538-7445.AM2013-706