Modulation of tumor immune microenvironment by TAS-115, a multi-receptor tyrosine kinase inhibitor, promotes antitumor immunity and contributes anti-PD-1 antibody therapy

TAS-115 is an oral multi-receptor tyrosine kinase inhibitor that strongly inhibits kinases implicated in antitumor immunity, such as colony stimulating factor 1 receptor and vascular endothelial growth factor receptor. Because these kinases are associated with the modulation of immune pathways, we investigated the immunomodulatory activity of TAS-115. An in vitro cytokine assay revealed that TAS-115 upregulated interferon γ (IFNγ) and interleukin-2 secretion by T cells, suggesting that TAS-115 activated T cells. Gene expression analysis suggested that TAS-115 promoted M1 macrophage differentiation. In in vivo experiments, although TAS-115 exerted a moderate antitumor effect in the MC38 mouse colorectal cancer model under immunodeficient conditions, this effect was enhanced under immunocompetent conditions. Furthermore, combination of TAS-115 and anti-PD-1 antibody exhibited greater antitumor activity than either treatment alone. Flow cytometry analysis showed the increase in IFNγ- and granzyme B (Gzmb)-secreting tumor-infiltrating T cells by TAS-115 treatment. The combination treatment further increased the percentage of Gzmb+CD8+ T cells and decreased the percentage of macrophages compared with either treatment alone. These results highlight the potential therapeutic effect of TAS-115 in combination with PD-1 blockade, mediated via activation of antitumor immunity by TAS-115.

Phialocephala fortinii increases aluminum tolerance in Miscanthus sinensis growing in acidic mine soil

Miscanthus sinensis growing in our study mine site contained a high concentration of Al in the adventitious roots. It has a root endophyte, Phialocephala fortinii, in its adventitious roots at a high frequency. The purpose of this study was to elucidate the effects of P. fortinii on Al tolerance mechanisms of M. sinensis and reveal potential underlying mechanisms. In the absence of P. fortinii, M. sinensis produced chlorogenic, citric, and malic acids that could act to alleviate Al toxicity in acidic mine soil. Up on fungal inoculation, the levels of these compounds were reduced, although the growth of seedlings and Mg concentration in the roots were increased. IAA production by the fungus may contribute to enhanced plant growth whereas an increase of Mg uptake could reduce toxicity of reactive oxygen species under Al stress. These actions of P. fortinii could promote growth and survival of M. sinensis in mine sites.

TAS4464, a NEDD8-activating enzyme inhibitor, activates both intrinsic and extrinsic apoptotic pathways via c-Myc-mediated regulation in acute myeloid leukemia

TAS4464, a potent, selective small molecule NEDD8-activating enzyme (NAE) inhibitor, leads to inactivation of cullin-RING E3 ubiquitin ligases (CRLs) and consequent accumulations of its substrate proteins. Here, we investigated the antitumor properties and action mechanism of TAS4464 in acute myeloid leukemia (AML). TAS4464 induced apoptotic cell death in various AML cell lines. TAS4464 treatments resulted in the activation of both the caspase-9-mediated intrinsic apoptotic pathway and caspase-8-mediated extrinsic apoptotic pathway in AML cells; combined treatment with inhibitors of these caspases markedly diminished TAS4464-induced apoptosis. In each apoptotic pathway, TAS4464 induced the mRNA transcription of the intrinsic proapoptotic factor NOXA and decreased that of the extrinsic antiapoptotic factor c-FLIP. RNA-sequencing analysis showed that the signaling pathway of the CRL substrate c-Myc was enriched after TAS4464 treatment. Chromatin immunoprecipitation (ChIP) assay revealed that TAS4464-induced c-Myc bound to the PMAIP1 (encoding NOXA) and CFLAR (encoding c-FLIP) promoter regions, and siRNA-mediated c-Myc knockdown neutralized both TAS4464-mediated NOXA induction and c-FLIP downregulation. TAS4464 activated both caspase-8 and caspase-9 along with an increase in NOXA and a decrease in c-FLIP, resulting in complete tumor remission in a human AML xenograft model. These findings suggest that NAE inhibition leads to anti-AML activity via a novel c-Myc-dependent apoptosis induction mechanism.

TAS6417/CLN-081 Is a Pan-Mutation-Selective EGFR Tyrosine Kinase Inhibitor with a Broad Spectrum of Preclinical Activity against Clinically Relevant EGFR Mutations

Despite the worldwide approval of three generations of EGFR tyrosine kinase inhibitors (TKI) for advanced non-small cell lung cancers with EGFR mutations, no TKI with a broad spectrum of activity against all clinically relevant mutations is currently available. In this study, we sought to evaluate a covalent mutation-specific EGFR TKI, TAS6417 (also named CLN-081), with the broadest level of activity against EGFR mutations with a prevalence of ≥1%. Lung cancer and genetically engineered cell lines, as well as murine xenograft models were used to evaluate the efficacy of TAS6417 and other approved/in-development EGFR TKIs (erlotinib, afatinib, osimertinib, and poziotinib). We demonstrate that TAS6417 is a robust inhibitor against the most common EGFR mutations (exon 19 deletions and L858R) and the most potent against cells harboring EGFR-T790M (first/second-generation TKI resistance mutation). In addition, TAS6417 has activity in cells driven by less common EGFR-G719X, L861Q, and S768I mutations. For recalcitrant EGFR exon 20 insertion mutations, selectivity indexes (wild-type EGFR/mutant EGFR ratio of inhibition) favored TAS6417 in comparison with poziotinib and osimertinib, indicating a wider therapeutic window. Taken together, we demonstrate that TAS6417 is a potent EGFR TKI with a broad spectrum of activity and a wider therapeutic window than most approved/in-development generations of EGFR inhibitors. IMPLICATIONS: TAS6417/CLN-081 is a potent EGFR TKI with a wide therapeutic window and may be effective in lung cancer patients with clinically relevant EGFR mutations.

Abstract 1329: Preclinical evaluation of TAS6417 as a highly effective, pan-mutation-selective EGFR tyrosine kinase inhibitor

Objectives: Three generations of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have developed to treat advanced non-small cell lung cancer (NSCLC) with EGFR mutations. However, each generation of TKI has different spectrum of activity against the different mutations. Currently, no EGFR TKIs are approved for NSCLC with EGFR insertion 20 mutation. Previously, we have shown that TAS6417, a novel EGFR TKI, is effective for cells harboring EGFR insertion mutations in vitro and in vivo. In this study, we asked whether TAS6417 is effective for tumors harboring other EGFR mutations observed in clinic.

Methods: Genetically engineered Ba/F3 cells expressing EGFR mutants, lung cancer cell lines including newly established cell lines established from tumors harboring EGFR insertion 20 were used to evaluate efficacy of erlotinib, afatinib, osimertinib, poziotinib, and TAS6417 by cell viability analyses. The selectivity indexes (the wild type EGFR/mutant EGFR ratio) were calculated to predict a therapeutic window for each TKI. Effects of each EGFR TKI on EGFR signaling and apoptosis were evaluated by western blotting. Finally, murine xenograft models were used to evaluate efficacy of TAS6417 and all generation of EGFR TKIs for the treatment of NSCLC with EGFR mutations.

Results: Cell viability assays demonstrate that TAS6417 was as potent as poziotinib against common EGFR mutations (L868R and exon 19 deletions) and the most potent against cells harboring the T790M resistant mutations. In addition, TAS6417 was effective in cells harboring EGFR rare mutations (G719X L861Q, and S768I). Even though IC50s were higher than those of poziotinib in cells harboring EGFR insertion 20, the selectivity indexes (the wild type EGFR/mutant EGFR ratio) were higher in TAS6417, indicating a wider therapeutic window. TAS6417 was effective in mice injected with cells harboring EGFR mutations with no body weight loss.

Conclusions: Our preclinical results confirm that TAS6417 is a potent EGFR TKI with a broader spectrum of activity and a wider therapeutic window and support clinical trials in the near future.

Citation Format: Hibiki Udagawa, Shinichi Hasako, Akihiro Ohashi, Naomi Abe, Tomonori Haruma, Toshiharu Komori, Miki Terasaka, Ryoto Fujita, Kaoru Funabashi, Hiroyuki Yasuda, Kazutaka Miyadera, Koichi Goto, Daniel B. Costa, Susumu S. Kobayashi. Preclinical evaluation of TAS6417 as a highly effective, pan-mutation-selective EGFR tyrosine kinase inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1329.

Abstract 4784: TAS0286/HM05, a novel highly selective RET inhibitor, prominently inhibits various RET defective tumor growth

The rearranged during transfection (RET) gene is a well-known proto-oncogene and encodes a single-pass transmembrane receptor tyrosine kinase. RET fusions and point mutations are oncogenic drivers in NSCLC, medullary thyroid cancer and other solid tumors, and therefore potential targets for cancer therapy. Multikinase inhibitors targeting the RET mutations have been tested in clinical trials with moderate efficacy in terms of tumor shrinkage and PFS.Moreover, multikinase inhibitors are characterized by poor tolerability due to off-target kinase inhibitory activities. To widen the therapeutic index, a selective RET kinase inhibitor is highly desirable. TAS0286/HM05 is a novel highly selective and potent RET kinase inhibitor.RET kinase assay was performed by homogeneous time-resolved fluorescence (HTRF) method. In-vitro proliferation studies and pharmacodynamics analyses were conducted in cancer cell lines with the RET fusions and RET activating mutations. The antitumor efficacy of TAS0286/HM05 was evaluated using mice xenograft models implanted with cancer cells with various RET gene abnormality. TAS0286/HM05 was orally administered for 14 or 28 consecutive days after grouping. In-vitro and in-vivo RET phosphorylation was detected using western blot analysis. The IC50 value for RET kinase of TAS0286/HM05 was below 1 nM. TAS0286/HM05 showed highly selective RET inhibitory activity among 283 kinases. In cellular assay, TAS0286/HM05 strongly suppressed phosphorylation of RET expressed in cells with various RET fusions and activating mutations, and inhibited cell proliferation at around 10 nM. At this concentration, apoptosis was also observed. The potency was higher than other multikinase inhibitors with RET inhibitory activity. Furthermore, in in-vivo efficacy studies, TAS0286/HM05 significantly inhibited the growth of tumors harboring various RET fusions and activating mutations at a range of 20 to 100 mg/kg/day without any body weight loss. The antitumor efficacy of TAS0286/HM05 was more potent than pre-existing multikinase inhibitors at their maximum tolerated dose. In particular, TAS0286/HM05 dramatically induced tumor regression of 40% within 15 days in animals implanted with LC-2/ad cells, a human lung adenocarcinoma cell line with CCDC6-RET fusion gene. TAS0286/HM05 is a novel and highly selective RET inhibitor with prominent tolerability. The potency of TAS0286/HM05 against tumors with RET abnormalities was stronger than currently marketed multikinase inhibitors being tested in NSCLC patients with RET fusions. TAS0286/HM05 is a promising agent for future clinical development in patients with RET gene abnormalities.

Citation Format: Hidenori Fujita, Isao Miyazaki, Masanori Kato, Yukari Yamada, Keiji Ishida, Tomonori Haruma, Haruka Nagasaki, Kenjiro Ito, Akihiro Hashimoto, Yasuo Kodama, Kaoru Funabashi, Emanuela Lovati, Kazutaka Miyadera, Kenichi Matsuo, Yoshikazu Iwasawa. TAS0286/HM05, a novel highly selective RET inhibitor, prominently inhibits various RET defective tumor growth [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 4784.

Abstract B180: TAS-115 attenuates tumor-associated macrophages and enhances sensitivity to anti-PD-1 monoclonal antibody in syngeneic mouse tumors

Background: Clinical efficacy of anti-PD-1 monoclonal antibody (mAb) has been established in various types of cancers. On the other hand, many patients remain unresponsive to anti-PD-1 mAb. Therefore, improvement in clinical response of anti-PD-1 mAb by using suitable combinational therapies and/or optimal methods for patient selection is needed. TAS-115 is a small molecular inhibitor of receptor tyrosine kinases (RTKs) such as the VEGFRs, MET, PDGFRs and CSF1R. Since these RTKs are reported to be involved in the cross talk between tumor micro-environment and immune system, we proposed that TAS-115 may strengthen the efficacy of anti-PD-1 mAb by influencing the immune system in the tumor micro-environment. In this report, we have examined whether TAS-115 could enhance the antitumor efficacy of anti-PD-1 mAb in mouse syngeneic tumors. Global analysis of immune cells was performed to explore the mechanisms for the interaction of TAS-115 and anti-PD-1 mAb. Material and Methods: MC38 (mouse colon carcinoma) was used as an anti-PD-1 mAb sensitive model, and EMT6 (mouse breast carcinoma) was used as an insensitive model to anti-PD-1 mAb. We investigated efficacy of TAS-115 alone and/or in combination with anti-PD-1 mAb in these mouse subcutaneous implanted syngeneic tumor models. In addition, by flow cytometric methods, global analysis of immune cells was done with tumor infiltrated leukocytes (TILs), spleen, tumor-draining lymph node and blood to investigate the effect of TAS-115 on antitumor immunity. Results: In the MC38 model, TAS-115 markedly suppressed tumor growth and increased the efficacy of anti-PD-1 mAb. In the EMT6 model, significant antitumor efficacy of TAS-115 was observed. Analysis of immune cells showed remarkable inhibition by TAS-115 in the ratio of tumor associated macrophages (TAMs) in both MC38 and EMT6 models. Effects of combination therapy of anti-PD-1 mAb with TAS-115 on TAMs and CD8+ T cells were also analyzed in the MC38 model. In the case of combination therapy, we found a decrease in the ratio of TAMs while there was an increase in the ratio of CD8+ T cells in TILs. Discussion: TAMs are considered as one of the major suppressive factors in tumor immunity and are thought to play an important role in resistance to anti-PD-1 mAb. Several kinds of RTKs are known to be involved in survival, proliferation and functions in TAMs. In particular, CSF1R plays major and important role in M2 macrophages regarded as potent suppressors of tumor immunity. Therefore, inhibition of these RTKs by TAS-115 may contribute to the decline of TAMs. As shown by the data reported here, the decrease of TAMs by TAS-115 may be involved in the antitumor efficacy and the enhancement of efficacy of anti-PD-1 mAb. Conclusion: TAS-115 attenuated tumor growth and TAMs in both anti-PD-1 mAb-sensitive and -insensitive mouse syngeneic tumor models. In addition, TAS-115 enhanced the antitumor efficacy of anti-PD-1 mAb. Therefore, TAS-115 may prove to be a useful adjunct to anti-PD-1 mAb.

Citation Format: Tomonori Haruma, Hidenori Fujita, Yukari Yamada, Satoshi Fukaya, Akihiro Hashimoto, Takafumi Harada, Takamasa Suzuki, Kenichi Matsuo, Teruhiro Utsugi, Yoshikazu Iwasawa. TAS-115 attenuates tumor-associated macrophages and enhances sensitivity to anti-PD-1 monoclonal antibody in syngeneic mouse tumors [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B180.

High Potency VEGFRs/MET/FMS Triple Blockade by TAS-115 Concomitantly Suppresses Tumor Progression and Bone Destruction in Tumor-Induced Bone Disease Model with Lung Carcinoma Cells

Approximately 25-40% of patients with lung cancer show bone metastasis. Bone modifying agents reduce skeletal-related events (SREs), but they do not significantly improve overall survival. Therefore, novel therapeutic approaches are urgently required. In this study, we investigated the anti-tumor effect of TAS-115, a VEGFRs and HGF receptor (MET)-targeted kinase inhibitor, in a tumor-induced bone disease model. A549-Luc-BM1 cells, an osteo-tropic clone of luciferase-transfected A549 human lung adenocarcinoma cells (A549-Luc), produced aggressive bone destruction associated with tumor progression after intra-tibial (IT) implantation into mice. TAS-115 significantly reduced IT tumor growth and bone destruction. Histopathological analysis showed a decrease in tumor vessels after TAS-115 treatment, which might be mediated through VEGFRs inhibition. Furthermore, the number of osteoclasts surrounding the tumor was decreased after TAS-115 treatment. In vitro studies demonstrated that TAS-115 inhibited HGF-, VEGF-, and macrophage-colony stimulating factor (M-CSF)-induced signaling pathways in osteoclasts. Moreover, TAS-115 inhibited Feline McDonough Sarcoma oncogene (FMS) kinase, as well as M-CSF and receptor activator of NF-κB ligand (RANKL)-induced osteoclast differentiation. Thus, VEGFRs/MET/FMS-triple inhibition in osteoclasts might contribute to the potent efficacy of TAS-115. The fact that concomitant dosing of sunitinib (VEGFRs/FMS inhibition) with crizotinib (MET inhibition) exerted comparable inhibitory efficacy for bone destruction to TAS-115 also supports this notion. In conclusion, TAS-115 inhibited tumor growth via VEGFR-kinase blockade, and also suppressed bone destruction possibly through VEGFRs/MET/FMS-kinase inhibition, which resulted in potent efficacy of TAS-115 in an A549-Luc-BM1 bone disease model. Thus, TAS-115 shows promise as a novel therapy for lung cancer patients with bone metastasis.

Abstract C178: TAS4464, a novel NEDD8 activating enzyme inhibitor, potently induces cell death via both intrinsic and extrinsic apoptotic pathways in acute myeloid leukemia

BACKGROUND: Acute myeloid leukemia (AML) is a heterogeneous disease characterized by numerous genetic mutations and chromosomal abnormalities. Current chemotherapies have shown limited efficacy in AML patients, most of whom develop chemoresistance and relapse repeatedly. Because the expression of anti-apoptotic proteins reportedly correlates with poor prognosis in AML, the modulation of apoptosis-related proteins emerges as a promising treatment strategy.

Apoptosis occurs mainly via two signaling pathways. In the mitochondria-mediated intrinsic apoptotic pathway, the release of cytochrome c triggers caspase-9 activation, which subsequently activates effector caspases (e.g., caspase-3). In the death receptor-mediated extrinsic apoptotic pathway, the binding of death receptor ligands to their receptors activates caspase-8 and, in turn, effector caspases, as in the intrinsic pathway. NEDD8 activating enzyme (NAE) inhibitors, which act on the NEDD8 conjugation pathway, induce quantitative changes in the substrates of E3 cullin-RING ligases (CRLs) and cause apoptosis in AML.

Here, we describe the mechanism by which our highly potent and selective NAE inhibitor TAS4464 promotes apoptosis in AML.

MATERIALS AND METHODS: Intracellular ATP levels were measured to assess in vitro cell growth. The effects of TAS4464 on NEDD8 conjugation, the protein levels of CRL substrates, and the activation of various caspases were evaluated by means of Western blotting. The transcription levels of the Noxa and c-FLIP genes were assessed by using qRT-PCR. The antitumor activity and in vivo pharmacodynamic activity of TAS4464 were evaluated in a THP-1 xenograft model.

RESULTS: TAS4464 led to cell growth arrest and cell death in AML cell lines with various genetic backgrounds, including the MLL-AF9 fusion gene and FLT3-ITD mutation. TAS4464 activated both caspase-9 (intrinsic apoptotic pathway) and caspase-8 (extrinsic apoptotic pathway); combined treatment with inhibitors of these caspases markedly diminished the TAS4464-associated induction of apoptosis.

By analyzing apoptosis-related factors in each apoptotic pathway, we found that TAS4464 increased the pro-apoptotic factor Noxa protein (intrinsic apoptotic pathway) and decreased the anti-apoptotic factor c-FLIP protein (extrinsic apoptotic pathway) with changes evident at the mRNA transcriptional level. In addition, treatment with TAS4464 led to accumulation of the CRL substrate c-Myc, and c-Myc knockdown by siRNA ablated the TAS4464-induced decrease in cFLIP protein.

Intravenous administration of TAS4464 on day 1, 3 and 5 for 3 weeks resulted in tumor growth inhibition (TGI) of 100% including complete response in human THP-1 xenograft model, compared with twice-weekly administration of cytarabine that resulted in a TGI of only 6%. Pharmacodynamics analysis revealed that TAS4464 inhibited cullin neddylation and induced activation of caspases in THP-1 xenografted tumor.

CONCLUSION: TAS4464 exerts a strong apoptosis-inducing effect in AML cell lines via both intrinsic and extrinsic apoptotic pathway by modulating apoptosis-related proteins. In addition, TAS4464 demonstrates marked antitumor activity in the THP-1 xenograft model. Given its potent preclinical activities, TAS4464 is a promising agent for treating AML.

Citation Format: Hiroaki Ochiiwa, Chihoko Yoshimura, Hiromi Muraoka, Keiji Ishida, Tomonori Haruma, Shingo Tsuji, Akihiro Hashimoto, Takashi Mizutani, Shuichi Ohkubo, Kenichi Matsuo, Teruhiro Utsugi, Yoshikazu Iwasawa. TAS4464, a novel NEDD8 activating enzyme inhibitor, potently induces cell death via both intrinsic and extrinsic apoptotic pathways in acute myeloid leukemia. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C178.

Abstract C104: TAS-121, a highly potent and mutant-specific EGFR inhibitor, modulates the immune system, resulting in anti-tumor immune responses

Background:

TAS-121 is one of the 3rd generation EGFR TKI, which specifically inhibits mutant EGFRs, and it leads to high cellular selectivity and potent antitumor activity in various in vivo models. TAS-121 is being investigated in patients with non-small cell lung cancer (NSCLC) harboring not only active mutant EGFR, but also acquired resistance mutation T790M in phase I study. immune-related events observed during treatment with TAS-121 in preclinical and clinical studies suggested that TAS-121 could modulate the immune system and, consequently, might partially contribute to anti-tumor effect. To prove this hypothesis, we examined the immuno-modulating potential of TAS-121 using MLR assay, TCR stimulation assay and in vivo syngeneic tumor models.

Material and methods:

Immune cell proliferation and cytokine production were confirmed by the CFSE dilution using flow cytometry, and ELISA assay, respectively. Anti-tumor immune response was analyzed in syngeneic models bearing with MC38 murine colon carcinoma cell line.

Results:

TAS-121 strongly induced the proliferation of CD4 T cells and CD8 T cells as well as stimulating cytokine production. Other EGFR TKIs, including 1st generation to 3rd generation agents, didn't show these effects. TAS-121 inhibited the growth of syngeneic tumor, MC38 in vivo, while no growth inhibition was observed in vitro. These data demonstrate that TAS-121 can induce anti-tumor immune responses.

Conclusions:

These findings suggest that TAS-121 could specifically modulate the immune system including T cells, leading to the anti-tumor immune responses. Therefore, TAS-121 has a unique profile among the 3rd generation EGFR-TKI. Considering this immune-modulating profile, combination with immune checkpoint blockade agent such as anti-PD1 monoclonal antibody might be beneficial for NSCLC patients harboring mutant EGFR.

Citation Format: Satoshi Fukaya, Yoshimi Aoyagi, Masanori Katoh, Kimihiro Itoh, Toshihiro Shibutani, Nozomu Tanaka, Tomonori Haruma, Akihiro Hashimoto, Kazutaka Miyadera, Kenichi Matsuo, Yoshikazu Iwasawa, Teruhiro Utsugi, Kazuhiko Yonekura. TAS-121, a highly potent and mutant-specific EGFR inhibitor, modulates the immune system, resulting in anti-tumor immune responses. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C104.

Abstract A108: TAS-115, a VEGFR/MET-targeted kinase inhibitor, potently suppresses HGF-induced aggressive bone and systemic metastasis in HGF knock-in mice bearing UM-UC-3 bladder tumors

Background:

Invasive bladder cancer frequently shows bone and systemic metastasis. Thus, development of a drug that is effective not only against the primary lesion but also the metastatic lesions is needed for therapy of bladder cancer. The expression level of hepatocyte growth factor (HGF) is high in invasive bladder cancer patients and associated with poor outcomes. Moreover, several recent clinical reports show that HGF receptor (MET) expression level was related to cancer grade, stage, tumor size, and poor prognosis in invasive bladder cancer patients.

Because HGF-MET signaling has shown a species difference between humans and mice, the usual human cancer xenotransplantation models using nude mice are inadequate to evaluate the effect of agents against tumor growth and metastasis driven by hHGF-MET paracrine signaling. Thus, hHGF knock-in (hHGF KI) mice were generated, and the antitumor efficacy of TAS-115, a MET/VEGFR-targeted kinase inhibitor, was evaluated in a systemic metastasis model of bladder cancer.

Material and Methods:

A luciferase-transfected human bladder cancer cell line (UM-UC-3-luc) was established. Cell proliferation, invasion, and gene expression analyses were conducted in UM-UC-3-luc after HGF stimulation using Cell titer Glo, a migration assay kit, and DNA array analyses. In the in vivo metastasis model, UM-UC-3-luc cells were injected into the left ventricular cavity of hHGF KI mice. Luciferase activity was measured under deep anesthesia once a week as an index of tumor growth. TAS-115 was administered orally once daily for 4 weeks, when photons emitted from tumor-transplanted regions reached the order of 107.

Results:

In vitro, HGF significantly enhanced proliferation and invasion of UM-UC-3-luc cells through MET activation. Based on DNA array analyses, several tumor metastasis and invasion-related genes (MMPs, chemokines, transcription factors, and phosphatases) were changed in UM-UC-3-luc cells after HGF stimulation. TAS-115 completely inhibited HGF-driven proliferation and invasion activity in UM-UC-3-luc cells and blocked HGF-induced expression changes of tumor metastasis and invasion-related genes in in vivo xenograft models.

Tumorigenicity and metastasis of UM-UC-3-luc cells showed approximately 60% increase in hHGF KI mice compared with WT mice. The major metastatic sites were lower jaw bone, adrenal gland, lymph node, and ovary. Tumor metastasis-related genes in UM-UC-3-luc cell-bearing hHGF KI mice were also changed, as in the in vitro experiments.

TAS-115 suppressed >80% of systemic metastasis of UM-UC-3-luc cells in both hHGF KI and WT mice without severe body weight loss. Notably, the more aggressive metastasis of UM-UC-3-luc cells in hHGF KI mice was clearly inhibited by TAS-115 treatment.

TAS-115 inhibited phosphorylation of MET and regulated tumor metastasis-related gene expression in metastasized tumor tissue.

Conclusions:HGF provided a more aggressive phenotype related to tumor progression to UM-UC-3-luc cells in this in vivo models. TAS-115, a VEGFR/MET-targeted kinase inhibitor, significantly suppressed tumor progression and systemic metastasis in UM-UC-3-luc cell-bearing hHGF KI mice. TAS-115 appears to be a novel therapeutic strategy for patients with advanced bladder cancer.

Citation Format: Yukari Yamada, Hidenori Fujita, Yayoi Fujioka, Naomoto Harada, Akihiro Hashimoto, Tomonori Haruma, Shingo Tsuzi, Ryouto Fujita, Kenichi Matsuo, Teruhiro Utsugi, Kazuhiko Yonekura. TAS-115, a VEGFR/MET-targeted kinase inhibitor, potently suppresses HGF-induced aggressive bone and systemic metastasis in HGF knock-in mice bearing UM-UC-3 bladder tumors. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A108.

Regular Feeding Plays an Important Role in Cholesterol Homeostasis Through the Liver Circadian Clock

Rationale: Peripheral clock control and the relevance of the circadian rhythm to physiology and disease are major questions in mammalian circadian biology.

Objective: We examined the physiological functions of the liver clock.

Methods and Results: We established a suppressed feeding schedule regimen constituting a high-cholesterol diet delivered every 6 hours without changes in energy and cholesterol intake. We found that rats exposed to this regimen developed hypercholesteremia. In the liver, the rhythmicity of expression of several clock genes was disrupted. Furthermore, the nocturnal expression of the CYP7A1 gene, which encodes the rate-limiting enzyme for the conversion of cholesterol to bile acids, was shifted to a diurnal pattern. Indeed, suppression of a regular feeding rhythm increased the secretion rate of very-low-density lipoprotein cholesterol from the liver and decreased the excretion of fecal bile acids.

Conclusions: Our results demonstrated that not only the amount and quality of food but also the timing of meals has crucial health implications.