Abstract PI3K/PTEN/AKT pathway has been found frequently activated and mutated in human breast cancer, which contributes to the development and progression of breast cancer as well as drug resistance. As genetic alteration of PIK3CA and PTEN as well as PI3K pathway activation are observed in almost all breast cancer categories, it is important to define the strategy for the development of PI3K inhibitors in breast cancer. BAY 80-6946 is a highly potent and selective pan-class I PI3K inhibitor in PhI clinical development. Molecular profiling of BAY 80-6946 in 24 breast tumor cell lines indicated that tumor cells with either PIK3CA mutation and/or HER2 expression were extremely sensitive to BAY 80-6946 with an average IC50 value of 17 (n=7) and 19 nM (n=8), respectively. In contrast wild type PIK3CA and HER2- breast tumor cells (n=12) were relatively insensitive or resistant to BAY 80-6946 with an average IC50 value of 773 nM. With regard to apoptosis induction, BAY 80-6946 demonstrated superior activity against other PI3K pathway inhibitors tested in PIK3CA mutant breast tumor cells. We found that the expression of Bcl-2, but not Mcl-1 nor survivin determined the sensitivity to apoptosis. Tumor cells that lack Bcl-2 expression immediately underwent apoptosis after exposure to BAY 80-6946. On the other hand, cells expressing high level of Bcl-2 such as T47D (PIK3CAmut) were resistant to the apoptosis induced by BAY 80-6946, despite a potent anti-proliferative activity of BAY 80-6946 (single-digit nM IC50). Combining BAY 80-6946 with ABT737 sensitized T47D cells to apoptosis, further supporting our hypothesis. On the other hand, PTEN-null, EGFRhigh and Bcl2 negative MDA-MB-468 tumor cells, are resistant to apoptosis induction by BAY 80-6946. Using shRNA and inhibitor against mTOR (TORC1 or TORC2), we identified an mTOR-dependent, PI3K-independent phosphorylation of AKT at S473, which might cause tumor cells resistance to the PI3K inhibition by BAY 80-6946. Rictor knockdown or combination with rapamycin can sensitize MDA-MB-468 to BAY 80-6946 with the respect to inhibition of proliferation and induction of apoptosis. Interestingly, the dual PI3K/mTOR inhibitor BEZ-235 could not induce apoptosis in MDA-MB-468, suggesting that the ratio of PI3K vs mTOR inhibition might be important in apoptosis induction. In conclusion, BAY 80-6946 was extremely effective to induce apoptosis in breast cancer cells expressing Her2 and/or PIK3CA mutation in the absence of Bcl-2. BAY 80-6946 in combination with anti-Bcl agents or mTOR inhibitors might be the promising approach to achieve tumor responses in Bcl-2 positive tumors or EGFR expressing/PTEN-null breast tumors, respectively. These findings provide a rationale to develop personalized therapies for the treatment of molecular subtypes of breast cancer. References:. N.Liu, et al. 101th AACR 2010 #4476 N.Liu, et al. 101th AACR 2010 #4478 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3833. doi:10.1158/1538-7445.AM2011-3833
Abstract Unlike normal cells, tumors undergo intensified de novo biogenesis of fatty acids (FAs) irrespective of the available circulating lipids. Acetyl-CoA carboxylase 1 (ACC) controls the rate limiting step in FA synthesis. ACC1 is up-regulated in a variety of human tumors and strongly associated with poorer prognosis in some tumor indications. Although targeting lipogenesis for cancer treatment appeared having strong rationale, drug discovery in this field has not been fully explored due to the lack of powerful tools for both evaluation and understanding the mode of action. Here we report the identification and the functional characterization of a highly selective ACC inhibitor BAY-ACC001, a ketoenol derivative using various pharmacological and lipidomic approaches to address the mechanism of ACC inhibition in cancer cells and its efficacy in preclinical tumor models. BAY-ACC001 inhibits human ACC1 and ACC1 with biochemical IC50s of 278 nM and 2590 nM measured by ACC1- or ACC2- mediated generation of ADP, respectively. In a cellular mechanistic assay using MCF7 tumor cells, BAY-ACC001 potently inhibited malonyl-CoA synthesis with an IC50 of 62 nM. Profiling BAY-ACC001 in a panel of 100 tumor cell lines revealed strong anti-proliferative activity in a sub-set of tumor cell lines with IC50s at low 3-digit nanomolar. Of note, in contrast to the potent activity in tumor cell lines, e.g. apoptosis induction in MCF7 breast tumor cells, ACC inhibitor showed only weak anti-proliferative effect and could not induce apoptosis in a set of non-transformed mammary epithelial cells. To elucidate the anti-tumor MoA, the levels of lipid components (∼400 lipid molecules) in MCF7 cells were analyzed using lipidomic technology. Interestingly, ACC inhibition did not lead to a simple depletion of lipid in cells, evident from a significant increase in tumor apoptosis-related lipid signaling molecules ceramides. These results suggested a bi-direction linkage between FA synthesis and the regulation of tumor cell survival. Single administration of BAY-ACC001 orally at 10 mg/kg (the maximum tolerable dose is 30 mg/kg, BID) in mice strongly reduced malonyl CoA levels in tumors. Treatment of BAY-ACC001 as single agent was efficacious in multiple tumor models, including MCF7 (breast), PC3 (prostate), HCT116 (colon) and MDA-MB-435 (melanoma) xenograft models; partial tumor remissions observed in MCF7 model. Furthermore, combination with Tamoxifen was synergistic in the MCF7 tumor model in vitro and in vivo. In conclusion, the prevalence of the exacerbated de novo FA synthesis observed in primary and metastatic tumors, the ACC-mediated novel survival signal transduction discovered in this study, and robust in vitro and in vivo anti-tumor activity of BAY-ACC001 provide a strong rationale for developing novel therapeutics targeting ACC for cancer treatment. Citation Format: Ningshu Liu, Maher Najar, Arne Scholz, Knut Eis, Ulf Bömer, Philip Lienau, Kai Thede, Dominik Mumberg, Michael Brands, Karl Ziegelbauer. BAY-ACC001, a novel ACC inhibitor, regulates fatty acids synthesis and lipid survival signaling with promising in vitro and in vivo activities in multiple preclinical tumor models. [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 4617. doi:10.1158/1538-7445.AM2013-4617
Abstract PTEFb/CDK9 mediated transcription of short-lived anti-apoptotic survival proteins like MYC, a key oncogene in multiple tumors, plays a critical role in cancer cell growth and survival. In addition, these survival proteins exhibit important functions in the development of resistance to chemotherapy. In contrast to pan-CDK inhibitors which are currently evaluated in Phase I and II clinical trials, to our knowledge PTEFb selective inhibitors have not been explored for clinical utility. We report for the first time the preclinical profile and structure of BAY 1143572, a novel selective PTEFb/CDK9 inhibitor currently being investigated in a Phase I clinical trial. BAY 1143572 had potent and highly selective PTEFb-kinase inhibitory activity in the low nanomolar range against PTEFb/CDK9 and an at least 50-fold selectivity against other CDKs in enzymatic assays. Furthermore, BAY 1143572 showed a favorable selectivity against a panel of non-CDK kinases in vitro. The potent enzymatic activity on PTEFb translated into broad antiproliferative activity against a panel of tumor cell lines with sub-micromolar IC-50 values. In line with the proposed mode of action, a concentration-dependent inhibition of the phosphorylation of the RNA polymerase II and downstream reduction of MYC mRNA and protein levels was observed in vitro. This inhibition was accompanied by an induction of apoptosis in cellular assays. BAY 1143572 also showed single agent in vivo efficacy at tolerated doses in various xenograft tumor models in mice and rats upon once daily oral administration. Potent anti-tumor activity characterized with partial or even complete remissions could be documented in models showing different MYC gene alterations like amplifications and translocations. Treatment with BAY 1143572 resulted in a transient inhibition of intratumoral MYC mRNA and protein levels and an induction of apoptosis in these models. The inhibition of MYC mRNA was also observed in blood cells of BAY 1143572-treated rats indicating the potential clinical utility of MYC in blood cells as a pharmacodynamic marker in clinical development. The in vivo efficacy of BAY 1143572 was significantly enhanced in combination with several chemotherapeutics in different solid tumor models. These pharmacology data provided the rationale for the initiation of clinical development of BAY 1143572 in advanced cancer patients (NCT01938638). In conclusion, our data provide preclinical proof of concept for BAY 1143572 as a potent and highly selective inhibitor of PTEFb/CDK9 with first-in-class potential. Further clinical evaluation of BAY 1143572 for the treatment of cancers dependent on the transcription of the key oncogene MYC and other short-lived survival proteins is warranted. Citation Format: Arne Scholz, Ulrich Luecking, Gerhard Siemeister, Philip Lienau, Ulf Boemer, Peter Ellinghaus, Annette O. Walter, Ray Valencia, Stuart Ince, Franz von Nussbaum, Dominik Mumberg, Michael Brands, Karl Ziegelbauer. BAY 1143572: A first-in-class, highly selective, potent and orally available inhibitor of PTEFb/CDK9 currently in Phase I, inhibits MYC and shows convincing anti-tumor activity in multiple xenograft models by the induction of apoptosis. [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 DDT02-02. doi:10.1158/1538-7445.AM2015-DDT02-02
Abstract Radium-223 dichloride (Ra-223) is a targeted alpha therapy that binds to newly formed bone matrix in bone metastases and induces DNA double-strand breaks in cancer cells, osteoblasts and osteoclasts. It is used for treating men with castration-resistant prostate cancer (CRPC) and bone metastases. Enzalutamide is a second-generation androgen receptor inhibitor also used for treating the same patient population, and the combination of Ra-223 and enzalutamide is currently being investigated in clinical trials. We evaluated the antitumor efficacy of Ra-223 and enzalutamide in the LNCaP intratibial model mimicking prostate cancer metastasized to bone. LNCaP prostate cancer cells were inoculated into the right tibia of male NOD.scid mice. The mice were randomized (n=9/group) based on serum PSA and treated with vehicle, Ra-223 (330 kBq/kg, i.v., Q4W x 2), enzalutamide (30 mg/kg, p.o., QD) or with a combination treatment of Ra-223 and enzalutamide, for 28 days. Serum PSA levels were analyzed at the end of the study and compared to the pre-treatment levels. Serum bone formation and resorption biomarkers, PINP and CTX, respectively, were measured during the study. Tumor-induced abnormal bone area, Ra-223 uptake and bone formation were determined by X-ray, gamma counter and histomorphometry, respectively. The healthy tibiae were evaluated by microCT. Combination treatment showed synergistic antitumor efficacy as observed by lower PSA levels when compared to the vehicle, Ra-223 or enzalutamide monotherapies (p=0.04, p=0.008 and p=0.002, respectively). A statistical interaction between Ra-223 and enzalutamide treatments was found (p=0.003), confirming the synergistic effect. In combination treatment, the serum PSA change relative to pre-treatment levels was 18% of the vehicle. Accordingly, a decreasing trend (p=0.08) in tumor-induced abnormal bone changes was associated with the combination treatment in the tumor-bearing tibiae (46% of the vehicle), whereas no changes in total bone structure were observed in the healthy tibiae. The serum levels of PINP and CTX were lowest in mice treated with the combination treatment. Compared to Ra-223 monotherapy, concurrent administration of enzalutamide with Ra-223 did not affect either Ra-223 uptake or bone formation rate in tumor-bearing or healthy tibiae, respectively. Compared to Ra-223 and enzalutamide monotherapies, the combination treatment demonstrated synergistic antitumor efficacy by decreasing PSA levels in the LNCaP intratibial model. Despite of prominent effects on tumor growth, the combination treatment was not observed to compromise bone health in the healthy tibiae. In conclusion, these preclinical results support the ongoing phase 3 trials PEACE III (NCT02194842) & ESCALATE (NCT04237584) of this combination. Citation Format: Mari I. Suominen, Matias Knuuttila, Jukka Vääräniemi, Birgitta Sjöholm, Esa Alhoniemi, Dominik Mumberg, Sanna-Maria Käkönen, Arne Scholz. Synergistic antitumor efficacy of radium-223 in combination with enzalutamide in the intratibial LNCaP prostate cancer xenograft model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1392.
Abstract Despite remarkable results in treating certain cancers, immune checkpoint inhibitors (ICIs) are lack of activity in ‘cold' tumors and not always effective in inflamed ‘hot' tumors. In addition to aberrant activation in cancer cells, the PI3K pathway plays both positive and negative roles in immune response. Therefore, the overall outcome of PI3K inhibition on anti-tumor immunity and the combination strategy with ICIs should be carefully investigated. In this study, PI3K inhibition alone and in combination with anti-PD-1/L1 were evaluated in a set of 8 representative syngeneic tumor models non-responding or insensitive to ICIs. We first compared an oral pan-PI3K inhibitor BAY 1082439 dosed continuously (QD) versus intermittently (2On/5Off), and performed a comprehensive evaluation of an approved intravenously dosed pan-PI3K inhibitor copanlisib (2On/5Off). We found that intermittent treatment, regardless oral or iv, produced better anti-tumor efficacy, increased intratumoral CD8+/Treg ratio and a better safety profile, while continuous inhibition of PI3K led to a significant reduction in splenic B cells and lymphoid organ weight. In addition, intermittent treatment of PI3K inhibitor with subsequent combination of anti-PD-1 induced complete tumor regression in 50-100% of animals bearing TreghighA20 tumor compared to 0% response in the monotherapy groups. Synergistic combination was also demonstrated in M2-TAMhigh CT26 and MC38 CRC models. Of note, no tumor growth was observed in a re-challenge study conducted 3 months post complete tumor regression in the combination group of the CT26 model, indicating that tumor specific memory T cells were generated which prevented tumor recurrence. Analysis of tumor infiltrating leukocytes revealed significant reductions in Treg and/or M2-TAM but increases in CD8+ T cell, Granzyme B+ cell, M1-TAM and activated DC. The findings in mice were also confirmed in human PBMC derived Treg (induced by TGF-β) and M2 (induced by M-CSF/IL-4) differentiation assays. The pan-PI3K inhibitor copanlisib, but not a PI3Kδ selective inhibitor, effectively blocked TGF-β-induced Treg (CD25+/FoxP3+) differentiation, despite both inhibitors suppressing CD3-stimulated Treg proliferation. Furthermore, copanlisib not only blocked M2 differentiation, but also could redirect differentiated M2 to immune stimulating M1 even in the presence of M-CSF/IL-4. Taken together, pulsatile pan-PI3K inhibition could effectively convert an immune suppressive effect observed with continuous treatment to a favorable anti-tumor immune response. Combination of intermittently dosed PI3K inhibitor copanlisib with ICIs therefore might be a promising strategy to overcome the resistance induced by intratumoral oncogenic signaling and an immune suppressive tumor microenvironment. Citation Format: Sarah Glaeske, Franziska Huebner, Anna Anurin, Andreas Janzer, Sabine Zitzmann-Kolbe, Juliane Paul, Katja Glaeske, Sandra Berndt, Dominik Mumberg, Matyas Gorjanacz, Karl Ziegelbauer, Bertolt Kreft, Ningshu Liu. Pulsatile inhibition of PI3K converts immune suppression by Tregs and M2-TAM to anti-tumor immune response in animal models insensitive or resistant to the monotherapies of PI3K and checkpoint inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-123.
Inhibition of monopolar spindle 1 (MPS1) kinase represents a novel approach to cancer treatment: instead of arresting the cell cycle in tumor cells, cells are driven into mitosis irrespective of DNA damage and unattached/misattached chromosomes, resulting in aneuploidy and cell death. Starting points for our optimization efforts with the goal to identify MPS1 inhibitors were two HTS hits from the distinct chemical series "triazolopyridines" and "imidazopyrazines". The major initial issue of the triazolopyridine series was the moderate potency of the HTS hits. The imidazopyrazine series displayed more than 10-fold higher potencies; however, in the early project phase, this series suffered from poor metabolic stability. Here, we outline the evolution of the two hit series to clinical candidates BAY 1161909 and BAY 1217389 and reveal how both clinical candidates bind to the ATP site of MPS1 kinase, while addressing different pockets utilizing different binding interactions, along with their synthesis and preclinical characterization in selected in vivo efficacy models.
Abstract MKNK1 (MAP kinase-interacting serine/threonine-protein kinase, also known as Mnk1) is activated by the mitogen-activated protein kinases ERK1/2 and p38. Thus, MKNK1 signaling is involved in the cellular response to environmental stress factors and cytokines. Of particular interest, MKNK1 kinase regulates mRNA translation by phosphorylating the translation initiation factor eIF4E (eukaryotic translation initiation factor 4E), known to be critical for malignant transformation but shown to be dispensable for translation in normal cells. Phosphorylated eIF4E levels were found to be elevated in several cancer tissues, including lung cancer. MKNK1 is also involved in resistance mechanisms to cancer therapeutics. Thus, the inhibition of MKNK1 activity may provide an innovative approach for anti-cancer therapy, and in particular for lung cancer, the main cancer-related cause of death worldwide. BAY 1143269 is a potent and selective MKNK1 inhibitor and inhibits eIF4E phosphorylation and reduces MKNK1-regulated translational downstream targets in non-small cell lung cancer (NSCLC) cell lines. In this study, BAY 1143269-mediated effects on molecular mechanisms in lung cancer models were analyzed. Epithelial-mesenchymal transition (EMT) is associated with the pathogenesis of numerous lung diseases including cancer progression, metastasis and resistance. BAY 1143269 reduced expression of EMT key regulators like Snail1 and cellular junction components, as well as reduced TGFβ1-induced EMT. Accumulating evidence suggests a role for proinflammatory cytokines in the development and progression of cancer; increased serum concentrations of cytokines like interleukin 6 (IL-6) are associated with diminished lung cancer survival rates. BAY 1143269 reduced the secretion of several proinflammatory cytokines, including TNFα and IL-6 in whole blood, and affected IFN-stimulated gene expression in cell lines. Consistent with the observed effects in vitro, BAY 1143269 showed significant anti-tumor effects in vivo in cell line as well as patient derived NSCLC xenograft models in monotherapy. In combination with chemotherapeutics approved for treatment of NSCLC, BAY 1143269 improved anti-tumor effects in comparison to chemotherapy alone. In conclusion, BAY 1143269 has the potential to provide therapeutic benefit in NSCLC. A phase I study of BAY 1143269 in combination with docetaxel for subjects with advance solid tumors is ongoing (NCT02439346). Citation Format: Susann Santag, Franziska Siegel, Antje M. Wengner, Claudia Lange, Ulf Boemer, Knut Eis, Florian Puehler, Martin Michels, Franz von Nussbaum, Karl Ziegelbauer, Dominik Mumberg, Kirstin Petersen. Preclinical mode of action and anti-tumor efficacy of the selective MKNK1 inhibitor BAY 1143269 in NSCLC models. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 341.
