PURPOSE: Tumor hypoxia activates hypoxia-inducible factors (Hifs), which induce a range of malignant changes including vascular abnormalities. Here, we determine whether inhibition of the hypoxic tumor response through myo-inositol trispyrophosphate (ITPP), a compound with antihypoxic properties, is able to cause prolonged vascular normalization that can be exploited to improve standardof-care treatment. EXPERIMENTAL DESIGN: We tested ITPP on two syngeneic orthotopic mouse models of lethal colorectal cancer liver metastasis. Tumors were monitored by MRI and analyzed for the hypoxic response and their malignant potential. A Hif activator and in vitro assays were used to define the working mode of ITPP. Hypoxic response and vasculature were re-evaluated 4 weeks after treatment. Finally, we determined survival following ITPP monotherapy, FOLFOX monotherapy, FOLFOX plus Vegf antibody, and FOLFOX plus ITPP, both overlapping and sequential. RESULTS: ITPP reduced tumor load, efficiently inhibited the hypoxic response, and improved survival. These effects were lost when mice were pretreated with a Hif activator. Its immediate effects on the hypoxic response, including an apparent normalization of tumor vasculature, persisted for at least 4 weeks after treatment cessation. Compared with FOLFOX alone, Vegf antibody combined with FOLFOX prolonged survival by <30%, whereas ITPP combined with FOLFOX extended survival by >140%, regardless of whether FOLFOX was given in overlap or after ITPP exposure. CONCLUSIONS: Our findings reveal a truly antihypoxic mechanism for ITPP and demonstrate the capacity of this nontoxic compound to potentiate the efficacy of existing anticancer treatment in a way amenable to clinical translation. Clin Cancer Res; 22(23); 5887-97. DOI: https://doi.org/10.1158/1078-0432. Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-125980 Accepted Version Originally published at: Limani, P; Linecker, M; Kachaylo, E; Tschuor, C; Kron, P; Schlegel, A; Ungethuem, U; Jang, J H; Georgiopoulou, S; Claude Nicolau, C; Lehn, J-M; Graf, R; Humar, B; Clavien, P-A (2016). Antihypoxic potentiation of standard therapy for experimental colorectal liver metastasis through myo-inositol trispyrophosphate. Clinical Cancer Research, 22 (23) Results. ITPP reduced tumor load, efficiently inhibited the hypoxic response, and improved survival. These effects were lost when mice were pretreated with a Hif activator. Its immediate effects on the hypoxic response, including an apparent normalization of tumor vasculature, persisted for at least four weeks after treatment cessation. Compared to FOLFOX alone, Vegf antibody combined with FOLFOX prolonged survival by <30%, whereas ITPP combined with FOLFOX extended survival by >140%, regardless of whether FOLFOX was given in overlap or after ITPP exposure. Conclusions.Our findings reveal a truly antihypoxic mechanism for ITPP and demonstrate the capacity of this nontoxic compound to potentiate the efficacy of existing antic...

To explore the general requirement of endothelial mTORC2 during embryonic and adolescent development, we knocked out the essential mTORC2 component Rictor in the mouse endothelium in the embryo, during adolescence and in endothelial cells in vitro. During embryonic development, Rictor knockout resulted in growth retardation and lethality around embryonic day 12. We detected reduced peripheral vascularization and delayed ossification of developing fingers, toes and vertebrae during this confined midgestational period. Rictor knockout did not affect viability, weight gain, and vascular development during further adolescence. However during this period, Rictor knockout prevented skin capillaries to gain larger and heterogeneously sized diameters and remodeling into tortuous vessels in response to FGF2. Rictor knockout strongly reduced extensive FGF2-induced neovascularization and prevented hemorrhage in FGF2-loaded matrigel plugs. Rictor knockout also disabled the formation of capillary-like networks by FGF2-stimulated mouse aortic endothelial cells in vitro. Low RICTOR expression was detected in quiescent, confluent mouse aortic endothelial cells, whereas high doses of FGF2 induced high RICTOR expression that was associated with strong mTORC2-specific protein kinase Cα and AKT phosphorylation. We demonstrate that the endothelial FGF-RICTOR axis is not required during endothelial quiescence, but crucial for midgestational development and sustained and extensive neovascularization in the adult.

Abstract-The mammalian target of rapamycin complex 2 (mTORC2) contains the essential protein RICTOR and is activated by growth factors. mTORC2 in adipose tissue contributes to the regulation of glucose and lipid metabolism. In the perivascular adipose tissue, mTORC2 ensures normal vascular reactivity by controlling expression of inflammatory molecules. To assess whether RICTOR/mTORC2 contributes to blood pressure regulation, we applied a radiotelemetry approach in control and Rictor knockout (Rictor aP2KO ) mice generated using adipocyte protein-2 gene promoter-driven CRE recombinase expression to delete Rictor. The 24-hour mean arterial pressure was increased in Rictor aP2KO mice, and the physiological decline in mean arterial pressure during the dark period was impaired. In parallel, heart rate and locomotor activity were elevated during the dark period with a pattern similar to blood pressure changes. This phenotype was associated with mild cardiomyocyte hypertrophy, decreased cardiac natriuretic peptides, and their receptor expression in adipocytes. Moreover, clock gene expression was reduced or phase-shifted in perivascular adipose tissue. No differences in clock gene expression were observed in the master clock suprachiasmatic nucleus, although Rictor gene expression was also lower in brain of Rictor aP2KO mice. Thus, this study highlights the importance of RICTOR/mTORC2 for interactions between vasculature, adipocytes, and brain to tune physiological outcomes, such as blood pressure and locomotor activity. (Hypertension. 2015;66:332-339.

<p>Supplementary Figure 1. ITPP increases O2 dissociation from hemoglobin. Supplementary Figure 2. Impact of ITPP on tumor burden, hypoxia and survival in the CT- 26/BALB model. Supplementary Figure 3. Impact of ITPP on metabolic and immune parameters in the CT- 26/BALB model at day 17. Supplementary Figure 4. Impact of ITPP on malignant tumor phenotype in the CT-26/BALB model at day 17. Supplementary Figure 5. Impact of oxygen levels and ITPP on cancer cells in vitro. One day after seeding MC-38 and CT-26 cells at hypoxia, cells were exposed or not to normoxia (A-C), or exposed to ITPP or saline (D-F) for 24h. Supplementary Figure 6. Impact of ITPP on tumor vasculature in the MC-38/B6 model at day 17. Supplementary Figure 7. Impact of ITPP on tumor vasculature in the CT-26/BALB model at day 17. Supplementary Figure 8. Long-term impact of ITPP on hypoxic response and tumor vasculature in the CT-26/BALB model.</p>

<p>Supplementary Methods and Figure Legends</p>