Kai Thede

In Vitro and In Vivo Activities of AIC292, a Novel HIV-1 Nonnucleoside Reverse Transcriptase Inhibitor

ABSTRACT Nonnucleoside reverse transcriptase inhibitors (NNRTIs) are important and frequently used elements of highly active antiretroviral therapy (HAART) for the treatment of human immunodeficiency virus type 1 (HIV-1) infection. However, the development of drug resistance, as well as the side effects of existing drugs, defines a medical need for novel NNRTIs with excellent tolerability, improved activity against NNRTI-resistant viruses, and a low barrier to resistance. Within the chemical class of diarylpyrazole-[imidazolidinone]-carboxamides, AIC292 was identified as a promising novel HIV-1 NNRTI and has successfully completed single-dose clinical phase I studies. Here, we report on the antiviral activity of AIC292, evaluated in vitro against wild-type and NNRTI-resistant HIV-1 isolates and in vivo using an engineered mouse xenograft model. AIC292 inhibited wild-type HIV-1 laboratory strains at low nanomolar concentrations, was well tolerated in different cell lines, and showed excellent selectivity in a lead profiling screen. In addition, activity of AIC292 could be demonstrated against a broad panel of wild-type HIV-1 group M and group O clinical isolates. AIC292 also retained activity against viruses harboring NNRTI resistance-associated mutations (RAMs), including the most prevalent variants, K103N, Y181C, and G190A. Interestingly, viruses bearing the L100I RAM were hypersusceptible to AIC292. Two-drug combination assays showed no antagonistic interactions between AIC292 and representative marketed HIV drugs with regard to antiviral activity. Furthermore, AIC292 displayed potent antiviral in vivo efficacy in a mouse xenograft model when applied once daily. Taken together, these data show that AIC292 represents a molecule with the antiviral properties of a novel NNRTI for the treatment of HIV-1 infection.

Abstract 4989: 3D spheroid screen yields SCD1 pathway inhibitors for the treatment of cancer

With three-dimensional growth conditions, multicellular tumor spheroids reproduce several parameters of the tumor microenvironment, including oxygen and nutrient gradients, characteristic of poorly vascularized tumor regions. 3D high content screening (HCS) identified compounds that selectively kill tumor cells in the inner core of tumor cell spheroids by targeting the Stearoyl CoA Desaturase 1 (SCD1) pathway. SCD1 catalyzes the rate-limiting step in the production of mono-unsaturated fatty acids (MUFAs). Cancer cells are dependent on higher levels of MUFAs compared to normal cells and SCD1 is highly expressed in multiple tumor types. Changes in the MUFA / SFA (saturated fatty acid) ratio alters lipid biosynthesis and thus triggers cellular (ER) stress and induces the Unfolded Protein Response. Although the lead compound was very effective in vitro, it had unfavorable PK and physical chemistry properties, including low permeability and solubility and very high lipophilicity. This led to insufficient oral bioavailability, which could be overcome by optimization of PK and physical chemistry properties. Here, we report on the in vitro/in vivo effects of our 3D HCS compounds which showed high potency in the 3D spheroid inner core death assay with T47D breast cancer cells. In this in vitro model compound-induced inner core cell death is enhanced by SCD1 substrates palmitic or stearic acid and rescued by the SCD1 products palmitoleic or oleic acid. Furthermore, the effects can be reproduced in 2D cultures, which become increasingly sensitive to inhibition by our 3D HCS compounds with decreasing FBS concentration in the culture medium and this effect can also be rescued by addition of MUFAs but not of palmitic acid. Mode of action analysis showed that our compounds reduced palmitoleoyl- or oleoyl-CoA levels and simultaneously increased saturated fatty acyl-CoAs of palmitate or stearate in several cell lines as well as in vivo. In the sensitive T47D cells, the compounds induced expression of stress response genes and genes related to lipid metabolism. While these results support the SCD1 pathway as target for our 3D HCS compounds, we also observed striking differences to published SCD1 inhibitors suggesting a new cancer target beyond SCD1. Thus, further validation of our inhibitors in vitro and in vivo will be required, but these results suggest that 3D spheroid cultures may be a valuable tool for elucidation of new drug targets for cancer therapy. Citation Format: Sylvia Gruenewald, Carolyn Sperl, Patrick Steigemann, Alexander Walter, Sylvia Zacharias, Uwe Eberspaecher, Roland Neuhaus, Ludwig Zorn, Wolfgang Schwede, Kai Thede, Sven Christian. 3D spheroid screen yields SCD1 pathway inhibitors for the treatment of cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4989. doi:10.1158/1538-7445.AM2017-4989

Abstract 1129: How to develop ACC1 inhibitors targeting lipid metabolism and oncogenic signaling pathways effectively and safely

Although targeting lipogenesis for cancer treatment appears to have a strong rationale, drug discovery in this field has not been fully explored due to the lack of understanding the mode of action as well as the therapeutic window. We reported previously on a class of novel ACC inhibitors with potent and selective activity against human ACC1, an isoform overexpressed in many cancer types. These ACC inhibitors revealed strong anti-tumor activity, including induction of tumor cell apoptosis in vitro and tumor regression in vivo in a sub-set of tumor models. To further demonstrate the therapeutic potential of ACC inhibitors, we conducted a series of studies in xenograft mice and rat to evaluate the anti-tumor efficacy of ACC inhibitors and to characterize their safety profile. We report that breast, prostate, and pancreatic cancers are among the most sensitive tumors to ACC inhibition. Interestingly, the anti-tumor kinetics correlated with reduction in palmitate levels without substantial changes in structural lipid components. In addition, a sub-type of KRAS mutation and activation of the Wnt pathway correlates with the sensitivity of tumors to ACC inhibitors. Treatment with ACC inhibitors at high doses caused an immediate decrease in food intake and followed with body weight loss. A clear correlation between the reduction of food intake and exposure of ACC inhibitor was observed. Upon withdrawing drug, the effect on food intake is restored. Therefore, we investigated intermittent dosing schedules and food effects on the tolerability and anti-tumor efficacy of ACC inhibitors. We could demonstrate that the tolerability was improved without compromising the efficacy compared to continuous treatment. Furthermore, feeding animals a high fat diet prevented body weight loss and meanwhile maintained the antitumor activity. These results indicate that strong reduction of food intake seems the cause of intolerability, which can be prevented and reversed either by intermittent dosing, or by exogenously supplementing with a high fat diet. Furthermore, for the first time we provided in vivo evidence that exogenous lipids could complement de novo lipogenesis inhibition in normal cells, while tumor growth requires lipogenesis irrespective of existing circulating lipids. In summary, these assessments provide scientific insights and strategy on how to best target tumor lipid metabolism and lipid signaling effectively and safely for cancer therapy. Citation Format: Ningshu Liu, Wilhelm Bone, Sendhil S. Velan, Krishnarao Doddapuneni, Jadegoud Yaligar, Kai Thede Thede, Ursula Moenning, Xiaohe Shi, Xianfeng Tian, Elissaveta Petrova1, Franz von Nussbaum, Dominik Mumberg, Michael Brands, Karl Ziegelbauer. How to develop ACC1 inhibitors targeting lipid metabolism and oncogenic signaling pathways effectively and safely. [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 1129. doi:10.1158/1538-7445.AM2015-1129

Abstract 4617: 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.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC 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 Bomer, 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