Abstract 4020: HMPL-760 is a highly potent and selective reversible BTK inhibitor, targeting BTK and BTKC481S in B-cell malignancies

Introduction: Bruton’s tyrosine kinase (BTK), a member of the Tec family, plays a crucial role in signaling through B-cell receptor (BCR). BTK inhibition blocks BCR signals and prevents B-cell activation and growth. First-generation BTK inhibitors such as ibrutinib covalently binds to a cysteine residue (C481) of BTK. Their most frequent acquired resistance is the development of a serine mutation in the binding site (C481S). Next generation BTK inhibitors such as LOXO-305 and ARQ 531 are being developed to overcome this resistance to first-generation inhibitors.

Methods: HMPL-760 was tested in biochemical assays using recombinant human wild type (WT) and C481S mutant BTKs. Its selectivity was carried out using Eurofins Cerep KinaseProfilerTM panel. Cellular activity of HMPL-760 was evaluated in HEK293 cells stably transfected with BTKWT or BTKC481S, and other tumor cell lines, which are either human diffuse large B cell lymphoma (DLBCL) or mantle cell lymphoma (MCL) cell lines. The in vivo antitumor activity and PKPD correlation of HMPL-760 was studied in HBL-1 xenograft mouse models bearing BTKWT or BTKC481S respectively.

Results: In biochemical assays, HMPL-760 strongly inhibits BTK kinase activities towards wild-type BTK (BTKWT) and C481S mutant (BTKC481S), and binds to BTK in a reversible way. HMPL-760 demonstrates high selectivity in a panel containing 413 kinases. In cellular assays, HMPL-760 displays strong anti-proliferative activities in B-cell lymphoma cells (TMD-8, OCI-LY10, REC-1, HBL-1 and HBL-1-BTKC481S) harboring either BTKWT or BTKC481S (GI50: 0.0015-0.046 μM). In human whole blood assay, HMPL-760 inhibits activation of B-cells at nanomolar concentrations measured by inhibition of immunoglobulin-induced CD69 expression in CD19+cells. HMPL-760 shows ≥ 10-fold inhibitory potency than ARQ 531 in both BTKWT and BTKC481S cells, and ~3-fold higher inhibitory potency than that of LOXO-305 in BTKC481S cells. In cellular assay by detecting p-BTK after compound washout, HMPL-760 maintains a longer duration of target inhibition than LOXO-305 in both BTK wild type (HBL-1) and BTK mutant (HBL-1-BTKC481S) cell lines. HMPL-760 displays dose-dependent antitumor efficacy in multiple human B cell lymphoma xenograft models in mice when orally administered at 3~50 mg/kg once daily. Complete tumor regression occurs in most of the tested models at the high dose levels. HMPL-760 shows much stronger antitumor efficacy than LOXO-305 and ARQ 531 at similar dose level, which may be associated with HMPL-760’s higher drug exposures and more sustainable inhibition on BTK phosphorylation in the tumor tissues.

Conclusion: HMPL-760 is a reversible, selective, highly potent, BTK inhibitor targeting both BTKWT and BTKC481S. The first-in-human Phase 1 clinical trials of HMPL-760 are under way in patients with r/r B-NHL (NCT05190068, NCT05176691).

Citation Format: Linfang Wang, Junqing Liang, Zhihu Gao, Jia Hu, Weigang He, Xianwen Yang, Fangfang Mao, Wei Zhang, Ying Yu, Qihang Zhang, Na Yang, Chun Zhang, Jian Wang, Yu Cai, Xiong Li, Weiguo Qing, Guangxiu Dai, Yongxin Ren, Michael Shi, Weiguo Su. HMPL-760 is a highly potent and selective reversible BTK inhibitor, targeting BTK and BTKC481S in B-cell malignancies. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4020.

Abstract 543: Preclinical characteristic of HMPL-306, a CNS-penetrable dual inhibitor of mutant IDH1 and IDH2

Background: Mutations in isocitrate dehydrogenase (IDH) 1/2 are frequently identified in various cancers, such as AML, cholangiocarcinoma, chondrosarcoma and glioma. Mutant IDHs (mIDHs) cause accumulated 2-HG, leading to blockage of cell differentiation, thereby inducing malignant transformation. Rare cases were identified carrying co-existing mutations in IDH1 and IDH2. mIDH isoform switching, from mutant IDH1 to mutant IDH2 and vice versa, have been reported as a mechanism of acquired resistance to IDH inhibition in AML and cholangiocarcinoma. Thus, simultaneous inhibition on both mIDH1 and mIDH2 may be a promising strategy to overcome resistance and improve clinical efficacy. HMPL-306, a dual inhibitor of mIDH1/mIDH2, developed by HUTCHMED, is being evaluated in clinical trials.

Methods: The inhibition of HMPL-306 on IDH enzymes, including mutant and wild type, was determined by fluorescence-based assay. The selectivity of HMPL-306 was evaluated in 322 kinases (SelectScreenTM) and 88 proteins (Cerep). For cellular activities of HMPL-306, 2-HG production and differentiation were detected in cells harboring mIDH. Human tumor xenograft models carrying IDH1 or 2 mutations were established for evaluating mIDH inhibition by detecting 2-HG in plasma and tumor, and anti-tumor efficacies.

Results: HMPL-306 inhibited mutant IDH enzyme activities including IDH1R132H, IDH2R140Q and IDH2R172K, while showed weaker inhibition on IDH1/2 wild type enzymes. HMPL-306 had a superior selectivity profile in a kinase panel and a safety panel, while enasidenib, an approved mIDH2 inhibitor, inhibited Adenosine-A3 with IC50 of 12 nM. In cellular assays, HMPL-306 displayed comparable activities to enasidenib and ivosidenib (approved mIDH1 inhibitor) and suppressed 2-HG through inhibition of mIDH1 or mIDH2 at similar level, indicating an equal potency against mIDH1 and 2. Moreover, in both mIDH1/2 cells, HMPL-306 reduced the levels of histone methylation, and promoted hemoglobin γ and Kruppel1 gene expression, which led to differentiation from immature malignant cells to mature normal cells. Oral administration of HMPL-306 remarkably decreased 2-HG level in plasma and tumor tissues in xenograft models carrying mIDH1 or mIDH2 and the inhibition is more potent and durable than either ivosidenib or enasidenib at the same dose. Pharmacokinetics (PK) study in rodents showed high exposures of HMPL-306 in brain and cerebrospinal fluid, a desirable feature for glioma therapy. Combination treatment of HMPL-306 and azacitidine synergized in releasing the differentiation block in mIDH AML cells. HMPL-306 also significantly improved in vivo anti-tumor efficacy of chemotherapy drugs in solid tumor models with mIDH1/2.

Conclusion: HMPL-306 is a potent, dual inhibitor of IDH1/2 mutation. The strong activity and favorable PK profiles support further clinical evaluation.

Citation Format: Na Yang, Jia Hu, Tingwen Li, Juntao Yu, Dongxia Shi, Min Cheng, Zeyu Zhong, Jian Wang, Yang Sai, Weiguo Qing, Guangxiu Dai, Yongxin Ren, Michael Shi, Weiguo Su. Preclinical characteristic of HMPL-306, a CNS-penetrable dual inhibitor of mutant IDH1 and IDH2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 543.

Associations between Sedentary Duration and Cognitive Function in Older Adults: A Longitudinal Study with 2-Year Follow-Up

OBJECTIVES

This study aimed to investigate the association between different forms of sedentary behavior and cognitive function in Chinese community-dwelling older adults.

DESIGN

A longitudinal study with a 2-year follow-up.

SETTING AND PARTICIPANTS

Data from 5356 participants at baseline and 956 participants at the follow-up of the Anhui Healthy Longevity Survey (AHLS) were analysed.

MEASUREMENTS

Cognitive function was evaluated by the Mini-Mental State Examination (MMSE), and mild cognitive impairment (MCI) was classified according to education-specific criteria. Self-report questionnaires were used to assess the sedentary behavior of the participants.

RESULTS

The participants who reported longer screen-watching sedentary duration had higher MMSE scores (1-2 hours: β=0.758, 95% CI: 0.450, 1.066; > 2 hours: β=1.240, 95% CI: 0.917, 1.562) and lower likelihoods of MCI (1-2 hours: OR= 0.787, 95% CI: 0.677, 0.914; >2 hours: OR=0.617, 95% CI: 0.524, 0.726). The participants who had played cards (or mahjong) sedentary had higher MMSE scores (β= 1.132, 95% CI: 0.788, 1.476) and lower likelihoods of MCI (OR=0.572, 95% CI: 0.476, 0.687). However, the participants who reported longer other forms of sedentary duration had lower MMSE scores (1-2 hours: β=-0.409, 95% CI: -0.735, -0.082; > 2 hours: β=-1.391, 95% CI: -1.696, -1.087) and higher likelihoods of MCI (1-2 hours: OR=1.271, 95% CI: 1.081, 1.496; > 2 hours: OR=1.632, 95% CI: 1.409, 1.889). No significant association was detected between sedentary duration and MCI incidence.

CONCLUSION

Variations in the impact of diverse sedentary behaviors on the cognitive function were detected in Chinese older adults. However, such associations were cross-sectional and longitudinal associations were not found in the current study.

Construction of immune cell infiltration score model to assess prognostic ability of tumor immune environment in lung adenocarcinoma

OBJECTIVES

The immune cell infiltration (ICI) in the tumor microenvironment (TME) can provide a reference for prognosis after immunotherapy. We aim to establish an ICI scoring model and evaluate its predictive ability for the immunotherapy efficacy and the prognosis in lung adenocarcinoma (LUAD) patients.

METHODS

We developed and analyzed the landscape of infiltrative immune cells based on the CIBERSORT and ESTIMATE algorithms. Then, three clusters of LUAD patients were discerned from TCGA-LUAD and GSE11969 data. Furthermore, two gene clusters were classified based on the PCA.

RESULTS

LUAD patients with better prognoses tend to have higher immune checkpoint expression and immune/stromal scores. There is a correlation between TMB and ICI, and their relationship deserves further exploration. Moreover, the early-stage and male patients with high ICI scores have more prolonged survival.

CONCLUSIONS

The feasibility of the ICI score model in evaluating prognosis after immune checkpoint therapy for LUAD patients was verified, specifically reflected in the screening of sensitive immune checkpoints as a treatment reference. The scoring system can accurately predict the overall survival of LUAD patients, which has clinical value to monitor disease and evaluate prognosis.

Abstract 5454: Amdizalisib (HMPL-689), a highly selective PI3Kδ inhibitor, exhibits potent anti-tumor activity in pre-clinical B-cell lymphoma models

Background: The delta isoform of PI3K (PI3Kδ) plays an important role in B-cell development and function by mediating the signaling of key receptors on B cells. Aberrant activation of PI3Kδ signaling pathway promotes the survival and proliferation of malignant B cells, making selective inhibition of this isoform a promising therapeutic approach for the treatment of B cell malignances. Amdizalisib (HMPL-689, Amdiz), discovered and being currently developed in a pivotal phase II clinical trial (NCT04849351) by HUTCHMED, is a highly potent and selective PI3Kδ inhibitor. Based on encouraging clinical data from the phase Ib study (2021 ESMO, abstract# 8330), Amdiz is a designated breakthrough therapy in China for treatment of relapsed and refractory follicular lymphoma. Herein, we report the pre-clinical anti-tumor activity of Amdiz.

Methods: Kinase activity was measured by Transcreener™ Fluorescence Polarization assay. The kinome selectivity profile of Amdiz was evaluated in Eurofins KinaseProfiler™ panel containing 323 kinases. Cell based phosphorylation of AKT was determined by using Acumen Explorer system. CD63 expression in basophils was evaluated by FACS assay. Inhibitory effects of Amdiz alone or in combination with other agents on cell viability were investigated in a panel of B cell lymphoma cell lines by CellTiter-Glo luminescent or CCK-8 assay. The ability of Amdiz to inhibit the activation of B cells in animals was evaluated in naïve rats using an ex vivo assay, and B cell activation was determined by evaluating CD86 expression using FACS analysis. Human B cell lymphoma cell line derived xenograft models were used to determine the anti-tumor activity of Amdiz in combination with other agents such as rituximab, BTK inhibitor, and venetoclax.

Results: Amdiz is a highly selective inhibitor of PI3Kδ, showing more than 250-fold selectivity over other PI3K isoforms and no significant inhibition over other 319 protein kinases at the concentration of 1 µM. Amdiz potently inhibited PI3Kδ in biochemical, cellular and human whole blood assays with IC50s ranging from 0.8-3 nM. Its inhibitory effects on cell viability were also evaluated in a panel of B -cell lymphoma cell lines. Results showed that Amdiz potently inhibited cell survival with IC50s from 0.005 to 5 μM. Amdiz showed a long-lasting and strong inhibition on B cell activation in a rat pharmacodynamics (PD) study at a dose as low as 0.1 mg/kg. Moreover, Amdiz significantly improved anti-tumor activity of standard-of-care agents as well as targeted agents in multiple B-cell lymphoma models both in vitro and in vivo.

Conclusion: Amdiz is a highly potent and selective PI3Kδ inhibitor with strong activity against B-cell lymphoma in pre-clinical studies, supporting clinical evaluation as either a single agent or in combination with other therapeutic agents for the treatment of B-cell malignancies.

Citation Format: Jia Hu, Jianhan Wang, Xiaoming Dai, Jianlin He, Junqing Liang, Ying Yu, Juntao Yu, Na Yang, Linfang Wang, Yu Cai, Xiong Li, Weiguo Qing, Yongxin Ren, Weiguo Su. Amdizalisib (HMPL-689), a highly selective PI3Kδ inhibitor, exhibits potent anti-tumor activity in pre-clinical B-cell lymphoma models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5454.

[The cervical microbiota characteristics in patients with human papillomavirus infection]

Objective: To investigate the characteristics of cervical microbiota in patients with HPV (Human Papillomavirus) infection, and to analyze the associations of cervical microbiota and HPV infection or cervicitis. Methods: 300 samples underwent HPV nucleic acid testing was collected in this case-control study from June 2019 to April 2020 in the Zhujiang Hospital of Southern Medical University, there were 150 cases allocated in HPV infection group (HPV+), and 150 cases of negative nucleic acid test were non-infectious Group (HPV-). Next-generation sequencing was used to sequence the V4 region of the bacterial 16S rRNA gene, and QIIME pipeline was used to analysis the microbiota composition of the two groups. Wilcoxon rank sum test and Kruskal-Wallis test were used to statistically analysis the differences of the microbiota between groups; and the α diversity and β diversity of the flora between groups were statistically analyzed by Adonis multivariate analysis of variance and Wilcoxon rank sum test. Results: A total of 300 samples were analyzed in this study, of which 150 samples were HPV-positive and 150 samples were HPV-negative; among HPV-positive cases, 132 were infected by high-risk HPV (88.0%), and 18 were low-risk HPV infections (12.0%). The composition of the cervical microbiota were significantly different between the HPV+group and the HPV-group, which in the HPV+group, the α diversity of the cervical microbiota were significantly increased (Shannon index, W=8 174, P<0.000 1; PD whole tree, W=8 887, P=0.001 7). The β diversity of the two groups was significantly different (Binary Jaccard, F=2.325 4, P=0.042 0; Bray Curtis, F=2.136 44, P=0.044 0). The relative abundance of Lactobacillus spp. and L.iners in the HPV+group sample decreased significantly (W=7 730, P<0.000 1; W=8 979, P=0.002 5), accompanied by enriched Achromobacter, Stenotrophomonas, Methylobacterium, Sneathia and Dialister. There was no significant difference in the composition of the cervical microbiota between high-risk HPV infection and low-risk HPV infection (F=4.100 4, P>0.05). In addition, cervicitis is significantly related to HPV infection (χ²=19.78, P<0.000 1), the composition of cervical flora has similarity features in cervicitis and HPV infection samples. Compared with the normal group, the cervical microbiota of cervicitis with HPV infection is mainly enriched in Achromobacter, Aerococcaceae, Streptococcus, Fusobacteria, and Xanthomonadaceae. Conclusion: The cervical microbiota of patients with HPV infection has a significant dysbiosis, with increased diversity and significant depletion of lactobacillus, accompanied by an increase in the abundance of pathogenic bacteria such as Achromobacter.

Inhibition of Sumoylation Alleviates Oxidative Stress-induced Retinal Pigment Epithelial Cell Senescence and Represses Proinflammatory Gene Expression

PURPOSE

Advanced age is the largest risk factor for age-related macular degeneration (AMD). Sumoylation is a reversible post-translational modification that conjugates small peptide, small ubiquitin-like modifier (SUMO), to a target protein. Dysregulation of sumoylation is recently found to be critically involved in several age-related disorders. However, the effects of sumoylation during retina senescence and aging remains elusive. This study is aimed to investigate the function and regulation of sumoylation pathway in the aging retina and premature senescent retinal pigment epithelial (RPE) cells.

METHODS

1.5- and 10-month C57/B6 mice were used for comparative aging study. Both ARPE primary cultures and ARPE-19 cells were used for assay systems. The qRT-PCR was used for analysis of mRNA expression. Western blot and immunofluorescence were used to analyze the protein expression. Cell flow cytometry was used for cell cycle progression analysis. RPE barrier function and senescent-associated β-galactosidase (SA β-gal) activity were analyzed to measure cellular senescence.

RESULTS

We show that the expression of SUMO enzymes and global protein sumoylation were downregulated in the aging mouse retina, and in the oxidative stress (OS) -induced premature senescent RPE cells. Dramatical altered distribution of SUMO E1, E2 and E3 enzymes were observed during RPE senescence. Inhibition of sumoylation alleviated OS-induced cell senescence in RPE cells, as indicated by decreased p21 and p53 expression and decreased percentage of cell cycle arrest at G0/G1 phase. Intriguingly, inhibition of SUMO E1 repressed the expression of proinflammatory cytokine and chemokine in the premature senescent RPE cells. However, inhibition of sumoylation did not prevent DNA damage during the OS-induced RPE senescence process.

CONCLUSIONS

Our data indicate sumoylation critically regulates retina and RPE aging and that targeting sumoylation process may provide potential therapeutic strategy for AMD treatment.

Preclinical pharmacokinetics, disposition, and translational pharmacokinetic/pharmacodynamic modeling of savolitinib, a novel selective cMet inhibitor

Savolitinib is a novel small-molecule selective cMet inhibitor. This work characterized its pharmacokinetics in preclinical phase, established the preclinical relationships between PK, cMet modulation and anti-tumor efficacy. In vitro and in vivo animal studies were performed for PK characterization. Savolitinib showed good absorption, moderate tissue distribution, low to intermediate clearance, and low accumulation. Hepatic oxidative metabolism followed by urinary and biliary excretions was the major elimination pathway. Based on preclinical PK data, human PK profiles were predicted using empirical methods. Pharmacodynamic studies for evaluating cMet inhibition and anti-tumor efficacy were conducted in nude mice bearing Hs746t xenograft. PK/PD models were built to link the PD measurements to nude mouse PK. The established integrated preclinical PK/PD model contained a two-compartment non-linear PK model, a biomarker link model and a tumor growth transit model. The IC₅₀ of cMet inhibition and the concentration achieving half of the maximal Hs746t tumor reduction by savolitinib were equal to 12.5 and 3.7 nM (free drug), respectively. Based on the predicted human PK data, as well as the established PK/PD model in nude mouse, the human PD (cMet inhibition) profiles were also simulated. This research supported clinical development of savolitinib. Understanding the preclinical PK/PD relationship of savolitinib provides translational insights into the cMet-targeted drug development.

Abstract 2089: Evaluation of fruquintinib, a potent and selective oral VEGFR inhibitor, in combination with targeted therapies or immune checkpoint inhibitors in preclinical tumor models

The development of therapies targeting tumor angiogenesis, tumor driver gene alterations and tumor immune evasion has made tremendous advancement in improving overall survival. However, efficacy may be limited and resistance often develops rapidly when targeting a single axis of tumorigenesis. Therefore, it is worthwhile to explore rational combination of therapies based on tumor-specific features. Fruquintinib is a potent and selective oral VEGFR inhibitor currently in Phase III clinical trials for non-small-cell lung cancer (NSCLC) and colorectal cancer (CRC). We report here the evaluation of anti-tumor effect of fruquintinib in preclinical animal tumor models in combination with therapies targeting tumor driver gene alterations such as EGFR and c-MET or with immune checkpoints. In NSCLC xenograft models with EGFR activation such as activating mutations, gene amplification or protein overexpression, fruquintinib plus an EGFR tyrosine kinase inhibitor such as gefitinib or theliatinib (HMPL-309) was found to be more efficacious than either monotherapy. For instance, in PC-9 subcutaneous tumor model carrying EGFR exon 19 deletion, single agent treatment with fruquintinib at 2 mg/kg and gefitinib at 5 mg/kg produced the tumor growth inhibition (TGI) of 58% and 63%, respectively, while the combination treatment resulted in a TGI of 100% and tumor regression was observed in 11 of 16 mice treated with combinational therapy. In multiple xenograft models derived from lung cancer or renal cell cancer with c-MET activation (amplification or over-expression), addition of fruquintinib to a c-MET inhibitor savolitinib (AZD6094, HMPL-504) also improved the tumor growth inhibition substantially. At the end of the efficacy studies, CD31 and phosphorylation of EGFR, c-MET, AKT and ERK were analyzed with immunohistochemistry and western blotting method in tumor tissues. The results suggested that the enhanced anti-tumor effect in combination therapy could be attributed to the simultaneous blockade of cell signaling in tumor cells (EGFR or c-MET) and VEGFR suppression in the tumor microenvironment. Up-regulation of the immune inhibitory checkpoints induced by VEGF is one of the important mechanisms for tumor cells to escape immune surveillance. In a syngeneic murine tumor model, co-administration of fruquintinib and anti-PD-L1 antibody was found to provide improved anti-tumor effect compared to fruquintinib or anti-PD-L1 single agent alone. Studies to understand the mechanism responsible for the combination effect are under way. All combinations with fruquintinib described above were well tolerated. The efficacy observed in these models suggested that simultaneous blockade of tumor angiogenesis and tumor cell signaling or immune evasion may be a promising approach in improving treatment outcomes.

Citation Format: Yongxin Ren, Qiaoling Sun, Jingwen Long, Shiming Fan, Renxiang Tang, Wei Zhang, Xuelei Ge, Jianxing Tang, Linfang Wang, Dongxia Shi, Hongbo Chen, Min Cheng, Weiguo Qing, Weiguo Su. Evaluation of fruquintinib, a potent and selective oral VEGFR inhibitor, in combination with targeted therapies or immune checkpoint inhibitors in preclinical tumor models [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 2089. doi:10.1158/1538-7445.AM2017-2089

Anti-tumor efficacy of theliatinib in esophageal cancer patient-derived xenografts models with epidermal growth factor receptor (EGFR) overexpression and gene amplification

Targeted therapy is not yet approved for esophageal cancer (EC). In this study, we first evaluated EGFR gene and protein expression in 70 Chinese EC patient tumor samples collected during surgery. We then established 23 patient-derived EC xenograft (PDECX) models and assessed the efficacy of theliatinib, a potent and highly selective EGFR inhibitor currently in Phase I clinical study, in 9 PDECX models exhibiting various EGFR expression levels. Immunohistochemical analysis showed that 50 patient tumor samples (71.4%) had high EGFR expression. Quantitative PCR showed that eight tumors (11.6%) had EGFR gene copy number gain, and fluorescence in situ hybridization (FISH) revealed that four tumors had EGFR gene amplification. These results suggest that EGFR protein may be overexpressed in many EC tumors without gene amplification. Also detected were rare hot-spot mutations in EGFR and PIK3CA, whereas no mutations were found in K-Ras or B-Raf. Theliatinib exhibited strong antitumor activity in PDECX models with high EGFR expression, including remarkable tumor regression in two PDECX models with both EGFR gene amplification and protein overexpression. However, the efficacy of theliatinib was diminished in models with PI3KCA mutations or FGFR1 overexpression in addition to high EGFR expression. This study demonstrates that theliatinib could potentially benefit EC patients with high EGFR protein expression without mutations or aberrant activities of associated factors, such as PI3KCA or FGFR1.

Melatonin protects hepatocytes against bile acid-induced mitochondrial oxidative stress via the AMPK-SIRT3-SOD2 pathway

Mitochondrial oxidative damage is hypothesized to contribute to the pathogenesis of chronic cholestatic liver diseases. Melatonin, an indolamine synthesized in the pineal gland, shows a wide range of physiological functions, and is under clinical investigation for expanded applications. Melatonin has demonstrated efficient protective effects against various types of oxidative damage in the liver system. This study investigates the protective effects of melatonin pretreatment on glycochenodeoxycholic acid (GCDCA)-induced hepatotoxicity and elucidates the potential mechanism of melatonin-mediated protection. Melatonin markedly decreased mitochondrial ROS (mROS) production in L02 cells treated with 100 μM GCDCA, and inhibited GCDCA-stimulated cytotoxicity. Notably, melatonin exerted its hepatoprotective effects by upregulating sirtuin 3 (SIRT3) activity and its expression level, thus regulating superoxide dismutase 2 (SOD2) acetylation and inhibiting the production of mROS induced by GCDCA. Moreover, siRNA targeting SIRT3 blocked the melatonin-mediated elevation in mitochondrial function by inhibiting SIRT3/SOD2 signaling. Importantly, melatonin-activated SIRT3 activity was completely abolished by AMP-activated, alpha 1 catalytic subunit (AMPK) siRNA transfection. Similar results were obtained in rat with bile duct ligation or BDL. In summary, our findings indicate that melatonin is a novel hepatoprotective small molecule that functions by elevating SIRT3, stimulating SOD2 activity, and suppressing mitochondrial oxidative stress at least through AMPK, and that SIRT3 may be of therapeutic value in liver cell protection for GCDCA-induced hepatotoxicity.

Abstract B189: Synergistic effect of c-Met inhibitor savolitinib in combination with a VEGFR inhibitor fruquintinib in clear cell renal cell carcinoma xenograft models

Renal cell carcinoma (RCC) is the most common type of kidney tumor in human. Approximately 80∼85% of RCC is clear cell renal cell carcinoma (ccRCC).[1] Although VEGF/VEGFR targeted therapies bring significant advances in the treatment of RCC, ultimate resistance occurs in most cases following a transient period of clinical benefit. [2] The hepatocyte growth factor (HGF) receptor c-Met activation emerges as one of the mechanisms for resistance to anti-VEGF/VEGFR therapies in ccRCC,[3] implying that a combinational inhibition of c-Met and VEGFR pathways may induce a synergistic anti-tumor effect and could produce additional clinical benefit. The aim of this study was to assess the effect of a combination strategy targeting the VEGFR and c-Met pathways in ccRCC xenograft models. Savolitinib (AZD6094, HMPL-504) is a highly selective inhibitor against c-Met. Fruquintinib (HMPL-013) strongly inhibits VEGFR1, 2 and 3. Both of them were discovered by Hutchison MediPharma and are currently being evaluated in clinical trials for the treatment of various cancers. Several subcutaneous xenograft models were established in nude mice with human ccRCC cell lines or patient derived tumors (PDX) to investigate the anti-tumor effect of combination of savolitinib with fruquntinib. Treatment with savolitinib or fruquintinib at clinically relevant dose only exhibited mild to moderate tumor growth inhibition as a single agent in all of tested models, but significantly increased anti-tumor effect was observed in all of tested models for the combination group. It seemed that the enhanced anti-tumor effect was associated with c-Met inhibition. In a ccRCC PDX model KIN1T1342, the increased anti-tumor effect was correlated with dose increment of savolitinib. Immunohistochemistry (IHC) analysis revealed that combination treatment produced stronger inhibition on tumor proliferation marker Ki67 and angiogenesis marker CD31, compared to either savolitinib or fruquntinib alone, indicating that the observed synergistic effect might be attributed to the dual inhibition on tumor signaling and tumor microenvironment. C-Met expression was observed in all tested models, and treatment with savolitinib effectively suppressed phospho-Met. To evaluate c-Met expression in Chinese ccRCC patients, Formalin-Fixed and Parrffin-Embedded (FFPE) tumor sections were collected from sixty-two treatment-naive patients during surgical resection. Positive c-Met expression was found in 69% (43/62) of ccRCC samples under IHC staining.Overall our data demonstrated that c-Met was widely expressed in Chinese ccRCC patients and provided a rationale to test the combined HGF/c-Met and VEGF/VEGFR pathway blockade in the treatment of ccRCC in the clinical trials.

References:

1. Harshman LC et al. Cancer J. 2013;19: 316-323

2. Swanton C et al. Genome Med. 2010; 2(8): 53

3.Ciamporcero E et al. Mol Cancer Ther. 2015: 14 (1); 101-10.

Citation Format: Yongxin Ren, Shiming Fan, Yunxin Chen, Renxiang Tang, Wei Zhang, Jianxing Tang, Linfang Wang, Dongxia Shi, Hongbo Chen, Min Cheng, Weiguo Qing, Weiguo Su. Synergistic effect of c-Met inhibitor savolitinib in combination with a VEGFR inhibitor fruquintinib in clear cell renal cell carcinoma xenograft models. [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 B189.

Abstract LB-C22: Acquired resistance to the cMET inhibitor savolitinib in lung cancer models through EGFR/mTOR/MYC deregulation and adoption of PIM signaling

Lung cancer is the most common cause of cancer death globally with a significant, unmet need for more efficacious treatments. Aberrant receptor tyrosine kinase (RTK) signaling is a well-documented driver of disease onset and progression in multiple cancer types, including non-small cell lung cancer (NSCLC), where the cMET RTK contributes to tumor progression, maintenance and resistance to targeted therapies. Here, we explore the therapeutic potential of the potent and selective cMET inhibitor savolitinib (volitinib, AZD6094, HMPL-504) in NSCLC and begin to elucidate mechanisms of acquired savolitinib resistance in preclinical models. Using in vitro proliferation assays and immunoblot analysis, we determine that savolitinib rapidly inhibits cMET auto-phosphorylation/activation and reduces the viability of NSCLC cell lines NCI-H1993 and EBC-1 with a GI50 of 4.20 nM and 2.14 nM, respectively. In vivo, once daily treatment of NCI-H1993 xenografts with 3.0 mg/kg savolitinib significantly slows tumor growth, whereas treatment of EBC-1 xenografts with 30.0 mg/kg results in tumor stasis. Importantly, we observe tumor regressions in a patient-derived xenograft model of a NSCLC lymph node metastasis, HLXF-036LN, dosed with savolitinib 50.0 mg/kg once daily. Pharmacodynamic analysis of in vitro and in vivo models shows that savolitinib sensitivity correlates with blockade of PI3K/AKT and MAPK signaling, and interestingly, with cMYC (MYC) protein down-regulation. To elucidate mechanisms of acquired resistance in NSCLC, we generated savolitinib resistance in vitro using the NCI-H1993 and EBC-1 cell lines and further sub-cloned resistant NCI-H1993 cells to study the heterogeneity of resistance mechanisms. Using small-molecule screening, phospho-protein arrays and interrogation of signaling pathway activity by immunoblot, we identify 1) deregulated mTORC1/2 signaling and 2) the uncoupling of MYC expression from cMET activation as commonly contributing to resistance in all clones tested. RNA interference (siRNA) and MYC over-expression experiments confirm the novel finding that sustained MYC expression can partially drive resistance to a tyrosine kinase inhibitor such as savolitinib. Additionally, we identify clone-specific resistance mechanisms arising via a previously-described switch to EGFR dependence or by our novel finding of a de novo requirement for PIM signaling. Taken together, this work demonstrates the preclinical efficacy of savolitinib in NSCLC and provides an initial characterization of potential resistance mechanisms, identifying core resistance targets and clone-specific vulnerabilities that could be exploited to counter acquired savolitinib resistance that may emerge in the clinic.

Citation Format: Ryan E. Henry, Evan R. Barry, Brendon Ladd, Aleksandra Markovets, Garry J. Beran, Yongxin Ren, Feng Zhou, Lillian Castriotta, Ammar Adam, Weiguo Qing, Weiguo Su, Edwin Clark, Celina M. D'Cruz, Alwin Schuller. Acquired resistance to the cMET inhibitor savolitinib in lung cancer models through EGFR/mTOR/MYC deregulation and adoption of PIM signaling. [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 LB-C22.

Abstract 1730: A study on EGFR gene amplification and protein expression in Chinese esophagus cancer patients and antitumor effect of an EGFR inhibitor in patient-derived esophagus cancer models

Esophagus cancer is the fifth most common malignancy and the fourth leading cause of cancer mortality in China. According to Chinese cancer registry annual report in 2012, esophagus cancer accounts for nearly 1 in 10 of all cancer deaths. Despite the fact that much progress has been made in diagnosis and systemic chemotherapy regimens, the overall prognosis of esophagus cancer is disappointing. The 5-year survival rate, all stages included, is around 15∼25%. There remains a significant unmet medical need for esophagus cancer treatment.

EGFR expression was reported in 30∼90% esophagus cancers and overexpression of EGFR was found to be associated with poorer survival. Unlike colon cancer, K-ras mutation was less frequently found in esophagus cancer (5∼10%), suggesting EGFR pathway blockade might bring therapeutic benefit to those patients with EGFR activation or overexpression. In this study, as of November 2013, 35 surgical esophagus tumor samples were collected from a local hospital in Shanghai. 31 of the 35 samples were identified as squamous cell carcinoma. EGFR gene amplification, protein expression and K-ras mutation were studied. In addition, 9 patient derived esophagus cancer xenograft models (PDX) were developed and anti-tumor effect of a novel and highly potent EGFR inhibitor was evaluated in 6 PDX models.

Positive EGFR protein expression was found in 66% (23/35) of esophageal cancer samples. EGFR gene amplifications were observed in 9% patients (3/35). In 9 established PDX models, 7 of them showed EGFR expression and 2 with EGFR gene amplification. No K-ras mutation was observed in the 9 models. A novel and highly potent EGFR inhibitor (EGFRi), developed by Hutchison and currently being evaluated in phase I clinical trials in China, demonstrated potent anti-tumor activity in several PDX models with tumor growth inhibition in a range of 70% to &gt;100%. One PDX model with EGFR gene amplification and overexpression exhibited the highest sensitivity to EGFRi with remarkable tumor regression. EGFR signaling transduction was evaluated and the EGFRi inhibited phosphorylation of EGFR and downstream signaling molecules AKT and ERK.

In conclusion, EGFR expression and/or gene amplification was frequently found in Chinese esophagus cancer. EGFR inhibition resulted in potent anti-tumor effect in multiple patient derived esophagus cancer models carrying EGFR amplifications or high expression, suggesting the potential benefit that anti-EGFR agents might bring to esophagus cancer patients with abnormal EGFR activation.

Citation Format: Yongxin Ren, Jianming Zheng, Linfang Wang, Wei Zhang, Fang Yin, Jinghong Zhou, Xuelei Ge, Shiming Fan, Renxiang Tang, Junen Sun, Weiguo Qing, Weiguo Su. A study on EGFR gene amplification and protein expression in Chinese esophagus cancer patients and antitumor effect of an EGFR inhibitor in patient-derived esophagus cancer models. [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 1730. doi:10.1158/1538-7445.AM2014-1730

Discovery of (S)-1-(1-(Imidazo[1,2-a]pyridin-6-yl)ethyl)-6-(1-methyl-1H-pyrazol-4-yl)-1H-[1,2,3]triazolo[4,5-b]pyrazine (volitinib) as a highly potent and selective mesenchymal-epithelial transition factor (c-Met) inhibitor in clinical development for treatment of cancer

HGF/c-Met signaling has been implicated in human cancers. Herein we describe the invention of a series of novel triazolopyrazine c-Met inhibitors. The structure-activity relationship of these compounds was investigated, leading to the identification of compound 28, which demonstrated favorable pharmacokinetic properties in mice and good antitumor activities in the human glioma xenograft model in athymic nude mice.

Discovery of fruquintinib, a potent and highly selective small molecule inhibitor of VEGFR 1, 2, 3 tyrosine kinases for cancer therapy

VEGF/VEGFR signal axis has been proven to be an important target for development of novel cancer therapies. One challenging aspect in small molecular VEGFR inhibitors is to achieve sustained target inhibition at tolerable doses previously seen only with the long-acting biologics. It would require high potency (low effective drug concentrations) and sufficient drug exposures at tolerated doses so that the drug concentration can be maintained above effective drug concentration for target inhibition within the dosing period. Fruquintinib (HMPL-013) is a small molecule inhibitor with strong potency and high selectivity against VEGFR family currently in Phase II clinical studies. Analysis of Phase I pharmacokinetic data revealed that at the maximum tolerated dose of once daily oral administration fruquintinib achieved complete VEGFR2 suppression (drug concentrations were maintained above that required to produce >85% inhibition of VEGFR2 phosphorylation in mouse) for 24 hours/day. In this article, the preclinical data for fruquintinib will be described, including kinase enzyme activity and selectivity, cellular VEGFR inhibition and VEGFR-driven functional activity, in vivo VEGFR phosphorylation inhibition in the lung tissue in mouse and tumor growth inhibition in a panel of tumor xenograft and patient derive xenograft models in mouse. Pharmacokinetic and target inhibition data are also presented to provide a correlation between target inhibition and tumor growth inhibition.

Abstract 928: Volitinib (HMPL504), a novel, selective and potent cMET inhibitor, is efficacious in primary tumor models of cMET-driven gastric cancer

Gastric cancer (GC) incidence rates are amongst the highest in Asian countries including; China, Japan and Korea(1). 5-year survival rates in early stage disease have improved through aggressive combinations of surgery and chemo/radiotherapy. In late stage disease however, despite Her2 molecular segmentation and trastuzumab therapy, prognosis remains dismal and novel therapeutic options are urgently required(2).

The MET oncogene encodes the receptor tyrosine kinase for hepatocyte growth factor and controls genetic programs leading to cell growth, invasion and survival. Dysregulation of MET signaling is a common feature of a diverse range of human tumor types and thus represents a highly competitive and attractive therapeutic target. Volitinib (HMPL-504) is an orally bioavailable, highly selective and potent small molecule ATP-competitive inhibitor, which inhibits cMET autophosphorylation and downstream signaling (3). Volitinib is currently in Phase I clinical development. To evaluate the utility of volitinib in treating patients with GC, we established the incidence of cMET amplification and overexpression and attempted to correlate this with response to volitinib in primary GC tumor models. Elevated cMET gene copy number (amplification 5%, high polysomy 13%), and protein overexpression (12%, cases &gt; IHC 2+, 16% &gt; IHC1+) were detected in a cohort of 217 Chinese GC samples using fluorescent in situ hybridization (FISH) and immunohistochemical (IHC) approaches. In vitro proliferation assays were performed on a panel of 26 GC cell lines and profound sensitivity to volitinib was demonstrated in lines harboring elevated cMET gene copy number (GI50 range 6 to 49nM). In the cMET amplified GC xenograft model, Hs746t, once-daily oral dosing of volitinib (2.5mg/kg) elicited potent anti-tumour activity at well-tolerated doses (97% tumour growth inhibition after 16 days dosing, P&lt;0.0001) which correlated well with pharmacodynamic modulation of phospho-cMET signaling. To strengthen the translational relevance of these data, a panel of cMET amplified primary GC models were identified and established. In these models, volitinib demonstrated potent tumor growth inhibition or regressions (90% and 84% TGI at 10mg/kg/qd, all P&lt;0.0001), correlated with pharmacodynamic modulation of tumor phospho-cMET. In contrast, 10mg/kg/qd volitinib was inactive (18% TGI, P=0.2405) in a cMET non-amplified control model. We also evaluated the activity of volitinib in combination with docetaxel, a standard of care chemotherapeutic commonly used in the treatment of gastric cancer. In model Hs746t, volitinib demonstrated additive benefit when used with docetaxel at well tolerated doses. These data support the potential clinical utility of volitinib as a selective agent for the therapeutic treatment of gastric cancers harboring dysregulated cMET signaling.

Citation Format: Paul R. Gavine, Shiming Fan, Haihua Fu, Lu Han, Yuan Jie Liu, Jing Lv, Weiguo Qing, Yongxin Ren, Weiguo Su, Xinying Su, Huiying Wang, Liang Xie, Shirlian Xu, Wen Xu, XiaoLu Yin, Yongjuan Yu, Tianwei Zhang, Q.May Wang. Volitinib (HMPL504), a novel, selective and potent cMET inhibitor, is efficacious in primary tumor models of cMET-driven gastric cancer. [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 928. doi:10.1158/1538-7445.AM2013-928

Abstract 1808: HM-032, a novel PI3K/mTOR dual inhibitor, is active on K-Ras/Raf mutation tumors through up-regulation of Bim

PIK3CA gene amplification and mutations have been identified in many types of tumors, suggesting the deregulation of PI3K/AKT/mTOR axis plays pivotal roles in tumorigenesis and development. K-Ras/Raf mutation is recognized as one of the key drug resistant factors for tumors against TKIs. HM-032 was reported here as a potent, selective and reversible ATP-competitive PI3K/mTOR dual inhibitor with special apoptotic activity in tumor cells harboring K-Ras mutations. HM-032 showed potent kinase inhibition with IC50 of 0.0008, 0.002, 0.001, 0.002 and 0.001 µM on PI3Kα, β, δ, ≤ and mTOR, respectively. In human prostate PC3 cells, it inhibited p-AKTS473, p-S6 and p-4EPB1 with IC50s of 0.002, 0.015 and 0.056 μM. Of the 89 tumor cell lines from lung, colon, breast, ovarian, and other tumor types, it was found that tumor cells with HER2 gene amplification, or PIK3CA mutation were relatively more sensitive to HM-032. Attractively, HM-032 showed apoptotic induction activity in the tumor cells harboring Ras/Raf mutations through inhibiting p-Erk and increasing gene expression of pro-apoptotic protein Bim. This result suggested that HM-032 might bring benefits to patients carrying K-Ras/Raf mutations in the clinic. Consistent with in vitro studies, HM-032 exhibited significant tumor growth inhibition in a dose dependent manner on multiple human xenograft models, including breast tumor MDA-MB-361(PIK3CAE545K, Her2 amplification), lung tumors H460 (PIK3CAE545K, K-RasQ61H) and A549 (LKB1 del, K-RasG12S), and glioblastoma U87MG (PTEN del) after 3 weeks oral dosing. Correspondingly, decrease of p-AKT and p-S6 was observed in the tumor xenograft tissues upon treatment with HM-032. In addition, HM-032 exhibited unique in vivo PK properties characterized by low clearance and long t1/2, which supported the intermittent dosing schedule in xenograft models. Based on the pre-clinical study results, HM-032 is anticipated to be a promising agent against solid tumors including carrying Ras/Raf mutations.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1808. doi:1538-7445.AM2012-1808

Abstract 1797: Preclinical evaluation of HM-018, a potent and selective JAK inhibitor in the treatment of myloproliferative disorders

JAK2 kinase mutation V617F is prevalent in myeloproliferative diseases (MPD), including polycythemia vera (PV, 81-99%), essential thrombocytosis (ET, 41-72%) and primary myelofibrosis (PMF, 39-57%). This point mutation constitutively activates the JAK kinase and leads to oncogenic potential of host cells, and thus making JAK2 a promising molecular target for MPD therapy. HM-018 is a small molecule inhibitor against JAK kinase and the compound's preclinical anti-MPD effects from signal transduction to biological consequences were investigated. HM-018 was found to inhibit JAK kinase 1, 2, 3 and TYK with IC50 of 0.010, 0.006, 0.040 and 0.047 μM, respectively. The compound demonstrated &gt;100 folds selectivity against a panel of 63 kinases. In accordance with enzymatic activity, HM-018 suppressed ligand dependent or constitutive JAK activation in multiple cell lines as evidenced by the decrease of STAT3/5 phosphorylation. As a result, JAK dependent cell proliferation was significantly inhibited by HM-018. EPO-mediated mouse PV model was utilized to evaluate the in vivo efficacy of the compound. HM-018 could shrink enlarged mouse spleen, a typical symptom of PV, in a dose dependent manner accompanied with decreased STAT5 phosphorylation both in animal spleen and in bone marrow after oral dosing for 7 days. To better mimic MPD development in a more clinically-relevant manner, JAK2-V617F-tranfected 32D cells were injected into mice intravenously, and it was observed that oral treatment of HM-018 not only prolonged the animal's life span, but also reduced MPD-related symptoms, such as spleen weight increase and organ invasion by malignant cells. Meanwhile, HM-018 exhibited a favorable pharmacokinetic profile and acceptable safety window in rats. Based on the preclinical data, HM-018 demonstrated anti-MPD potency both in vitro and in vivo, and the studies have provided rationale to further develop this compound as possible MPD therapeutics.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1797. doi:1538-7445.AM2012-1797

Identification of novel, potent and selective inhibitors of Polo-like kinase 1

A series of pyrimidodiazepines was identified as potent Polo-like kinase 1 (PLK1) inhibitors. The synthesis and SAR are discussed. The lead compound 7 (RO3280) has potent inhibitory activity against PLK1, good selectivity against other kinases, and excellent in vitro cellular potency. It showed strong antitumor activity in xenograft mouse models.

Abstract 4499: HM5016699, a novel and selective PI3K/mTOR dual inhibitor

PI3KCA gene amplification and mutations have been identified in many types of tumors, suggesting the dysregulation of PI3K/AKT/mTOR axis plays pivotal roles in tumorigenesis and development. Reported here is the discovery of HM5016699 as a potent, reversible ATP-competitive PI3K/mTOR dual inhibitor for treatment of cancer. HM5016699 showed potent kinase inhibition with IC50 of 0.01, 0.206, 0.052, 0.051 and 0.059 µM on PI3Kα, β, γ, Δ and mTOR, respectively. It demonstrated high selectivity on PI3K family and mTOR over a panel of 274 kinases. Of the 67 tumor cell lines screened from lung, colon, breast, ovarian, and other tumor types, we found that the tumor cells with HER2 gene amplification or PTEN loss tended to be sensitive to HM5016699, while the tumor cells harboring PI3KCA mutations and wild type Ras/Raf were mostly sensitive to the compound. HM5016699 could also show p-Erk inhibition and apoptotic induction at higher concentrations in the tumor cells harboring Ras/Raf mutations, suggesting it might bring benefits to patients carrying Ras/Raf mutations in the clinic. Consistent with in vitro studies, HM5016699 exhibited dose dependent tumor growth inhibition on multiple human xenografts models. It was found that the tumors with PIK3CA mutation or PTEN deletion were highly sensitive to HM5016699 with ED50s ranging from 0.6 to 1.8 mg/kg in U87MG (pTEN null), SKOV3 (H1047) and H1975 (G118D), whereas in tumors with Ras/Raf mutations, such as DLD-1(G13D), A549 (G12S) and HT-29(V600E), its ED50s were from 3.0 to 15.0 mg/kg. The decreased phosphorylation of AKT and S6 was observed in the tumor xenograft tissues treated with HM5016699, which was well-correlated with compound exposure. Therefore, we concluded that HM5016699 demonstrated both in vitro and in vivo activity through acting on PI3K/mTOR pathway. HM5016699 exhibited a favorable pharmacokinetic profile and acceptable safety window in rats. The pre-clinical study results suggest that HM5016699 could be a promising anti-cancer agent.

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 4499. doi:10.1158/1538-7445.AM2011-4499

A small-molecule inhibitor of Bcl-XL potentiates the activity of cytotoxic drugs in vitro and in vivo

Inhibition of the prosurvival members of the Bcl-2 family of proteins represents an attractive strategy for the treatment of cancer. We have previously reported the activity of ABT-737, a potent inhibitor of Bcl-2, Bcl-X(L), and Bcl-w, which exhibits monotherapy efficacy in xenograft models of small-cell lung cancer and lymphoma and potentiates the activity of numerous cytotoxic agents. Here we describe the biological activity of A-385358, a small molecule with relative selectivity for binding to Bcl-X(L) versus Bcl-2 (K(i)'s of 0.80 and 67 nmol/L for Bcl-X(L) and Bcl-2, respectively). This compound efficiently enters cells and co-localizes with the mitochondrial membrane. Although A-385358 shows relatively modest single-agent cytotoxic activity against most tumor cell lines, it has an EC(50) of <500 nmol/L in cells dependent on Bcl-X(L) for survival. In addition, A-385358 enhances the in vitro cytotoxic activity of numerous chemotherapeutic agents (paclitaxel, etoposide, cisplatin, and doxorubicin) in several tumor cell lines. In A549 non-small-cell lung cancer cells, A-385358 potentiates the activity of paclitaxel by as much as 25-fold. Importantly, A-385358 also potentiated the activity of paclitaxel in vivo. Significant inhibition of tumor growth was observed when A-385358 was added to maximally tolerated or half maximally tolerated doses of paclitaxel in the A549 xenograft model. In tumors, the combination therapy also resulted in a significant increase in mitotic arrest followed by apoptosis relative to paclitaxel monotherapy.

Small-molecule MDM2 antagonists reveal aberrant p53 signaling in cancer: implications for therapy

The p53 tumor suppressor retains its wild-type conformation and transcriptional activity in half of all human tumors, and its activation may offer a therapeutic benefit. However, p53 function could be compromised by defective signaling in the p53 pathway. Using a small-molecule MDM2 antagonist, nutlin-3, to probe downstream p53 signaling we find that the cell-cycle arrest function of the p53 pathway is preserved in multiple tumor-derived cell lines expressing wild-type p53, but many have a reduced ability to undergo p53-dependent apoptosis. Gene array analysis revealed attenuated expression of multiple apoptosis-related genes. Cancer cells with mdm2 gene amplification were most sensitive to nutlin-3 in vitro and in vivo, suggesting that MDM2 overexpression may be the only abnormality in the p53 pathway of these cells. Nutlin-3 also showed good efficacy against tumors with normal MDM2 expression, suggesting that many of the patients with wild-type p53 tumors may benefit from antagonists of the p53-MDM2 interaction.

Anti-solasodine glycoside single-chain Fv antibody stimulates biosynthesis of solasodine glycoside in plants

We constructed a recombinant antibody fragment--single chain fragment-variable (scFv) antibody--derived from hybridoma cell lines to control the concentration of solasodine glycosides in hairy root cultures of Solanum khasianum transformed by the anti-solamargine (As)-scFv gene. The properties of the As-scFv protein expressed in Escherichia coli were almost identical to those of the parent monoclonal antibody (MAb). Up to 220 ng recombinant As-scFv was expressed per milligram of soluble protein in transgenic hairy root cultures of S. khasianum. The concentration of solasodine glycosides was 2.3-fold higher in the transgenic than in the wild-type hairy root, as reflected by the soluble As-scFv level and antigen binding activities. These results suggested that the scFv antibody expressed in transgenic hairy roots controlled the antigen level, thus representing a novel plant breeding methodology that can produce secondary metabolites.

Induction of differentiation by 1alpha-hydroxyvitamin D(5) in T47D human breast cancer cells and its interaction with vitamin D receptors

The role of the active metabolite of vitamin D, 1,25 dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), in cell differentiation is well established. However, its use as a differentiating agent in a clinical setting is precluded due to its hypercalcaemic activity. Recently, we synthesised a relatively non-calcaemic analogue of vitamin D(5), 1alpha-hydroxyvitamin D(5) (1alpha(OH)D(5)), which inhibited the development of carcinogen-induced mammary lesions in culture and suppressed the incidence of chemically induced mammary carcinogmas in rats. In the present study, we determined the differentiating effects of 1alpha-(OH)D(5) in T47D human breast cancer cells and compared its effects with 1,25(OH)(2)D(3). Cells incubated with either 10 or 100 nM of the analogues inhibited cell proliferation in a dose-dependent manner, as measured by the dimethylthiazolyl-2,5-diphenyltetrazolium bromide (MTT) assay. Similar growth-inhibitory effects were also observed for MCF10(neo) cells. Both vitamin D analogues induced cell differentiation, as determined by induction of casein expression and lipid production. However, MCF10(neo) cells failed to respond to either vitamin D analogue and did not undergo cell differentiation. Since the cell differentiating effect of vitamin D is considered to be mediated via the vitamin D receptor (VDR), we examined the induction of VDR using reverse transcriptase-polymerase chain reaction (RT-PCR) in both cells. The results showed that, in T47D cells, both 1,25(OH)(2)D(3) and 1alpha(OH)D(5) induced VDR in a dose-dependent manner. Moreover, both analogues of vitamin D upregulated the expression of vitamin D response element-chloramphenicol acetyl transferase (VDRE-CAT). These results collectively indicate that 1alpha-(OH)D(5) may mediate its cell-differentiating action via VDR in a manner similar to that of 1,25(OH)(2)D(3).

Study of nm23 gene expression in an N-methyl-N-nitrosourea transformed human breast epithelial cell line

In the present study we pinpoint the time of nm23 down-regulation during the chemical transformation of the human breast epithelial cell line HBL100. The non-malignant HBL100 was transformed by exposing it to N-methyl-N-nitrosourea (MNU). We subsequently injected the transformed cells (HBL-T-MNU) into nude mice, resulting in tumor growth. With a second passage of these tumors in mice we observed lung and extra-regional node metastases. The expression of nm23 in the non-tumorigenic HBL100 cells was compared to the tumorigenic KBL-T-MNU cells as well as to the metastatic cell line HBL-T2(MNU) derived from the tumor induced by HBL-T-MNU cells. By using immunohistochemistry and Western blot analysis we documented the downregulation of nm23 expression in the tumorigenic HBL-T-MNU and metastatic HBL-T2(MNU) cell lines, as compared to the parental line HBL100. Once downregulated, nm23 expression in this model remains constant during the subsequent progression. These results suggest that nm23 down-regulation may indeed be associated with early neoplastic transformation and is maintained throughout neoplastic progression and metastatic stage.

Identification of genes induced by interleukin-3 and erythropoietin via the Jak-Stat5 pathway using enhanced differential display-reverse southern

Cytokines mediate their effects on growth and maturation of hematopoietic cells by binding to their cognate receptors and activating target genes. Interleukin-3 (IL-3) and erythropoietin (Epo) induce signal transduction via the Jak-Stat pathway. We report here on the identification of several known and novel genes induced by IL-3 and Epo, using a modified version of the PCR-based technique, enhanced differential display (EDD). We modified the technique to facilitate the screening and verification of the differential expression of the genes by using reverse Southern blotting (RS) and PCR-Southern blotting, and we called it EDD-RS. From the initial 110 genetags that were identified as differential expressed genes, 14 contained more than one gene. Among the differentially expressed genes, 24 are known genes and 39 are novel genes. Several of the known genes, such as IRF-1 and P21waf, were previously observed by others to be induced by IL-3 and Epo, but their dependence on Stat5 activation in cytokine-dependent cells was unknown. Other known genes, such as crp and Mssp2/1, were not described previously as target genes for cytokine induction. The results demonstrate that EDD-RS is an efficient method to identify cytokine-induced genes and can be productive in delineating the signal required for their induction.

Economic analysis of the use of recombinant human granulocyte colony stimulating factor in autologous bone marrow transplantation

The aim of this study was to assess the economic impact of the use of granulocyte colony stimulating factor (RHu-G-CSF) in patients treated by autologous bone marrow transplantation (ABMT) for lymphomas. Demographic, clinical and economic data were collected retrospectively from a random sample of 55 patients in four French centres who underwent ABMT (usual care) without or with administration of RHu-G-CSF over a period of 100 days post-ABMT. The patients treated with RHu-G-CSF had a shorter period of infection, neutropenia and severe neutropenia (P < 0.05) when compared with usual care recipients. Compared to usual care, the use of G-CSF was associated with a 3% reduction in total cost of care for ABMT over 100 days post-ABMT or US$1316, including RHu-G-CSF cost. This cost reduction was mainly due to a reduced length of stay in hospital and fewer laboratory tests.

Economic analysis of Alzheimer's disease in outpatients: impact of symptom severity

To assess the economic burden of Alzheimer's disease (AD), we carried out a cross-sectional prevalence cost-of-illness study in France. Fifty-one probable AD patients (NINCDS-ADRDA) actually treated in ambulatory care were recruited in two university outpatient centers. Demographic, clinical (including actual Mini-Mental State Examination scores), and economic data were collected by clinical investigators and trained interviewers. Total costs included actual expenditures such as direct medical costs and direct nonmedical costs, as well as indirect costs (loss of earnings due to loss of productivity). Cost valuation was based on the societal perspective using an opportunity costing approach. We found that indirect costs represented a significant portion of total costs (36%-40%). In terms of expenditures, patients and caregivers were found to bear the major part of AD total costs. We found a positive and significant correlation between disease severity and costs. Our findings support the hypothesis of a relationship between disease evolution and healthcare costs.

Methodological approaches to pharmaco-economics

Due to the increased need for cost-containment policies, most decision makers are facing the issue of the efficiency of health care strategies. In this context, economic evaluation becomes a major instrument. However, the credibility of economic data depends on a number of methodological steps: selection of strategy of economic evaluation (cost/effectiveness, cost/benefit, generation of economic hypotheses, study design (cross-sectional, prospective, naturalistic), data collection (data-base, physicians), data analysis (costing, statistics). In this respect, the conduct of proper economic evaluation relies on a combination of expertise in clinical epidemiology as well as in health economics.

Economic analysis of lenograstim in the correction of neutropenia following chemotherapy for non-Hodgkin's lymphoma

A prospective economic analysis of lenograstim and placebo was performed as part of a randomised double-blind trial in 162 patients receiving chemotherapy for non-Hodgkin's lymphoma (NHL). The primary clinical end-point was the percentage of patients experiencing > or = 1 documented infection in each treatment group. The cost of hospitalisation and the cost of medical services used were the primary economic end-points. Economic analysis was based on the French Hospital perspective. Over the 56-day study period, patients in the placebo group received more days of inpatient intravenous (8.9 vs 5.3 days; p < 0.01) and oral (5.3 vs 4.2 days) antibiotic therapy than those in the lenograstim group. This difference was due to a higher rate of documented infection in the placebo group. Patients treated with placebo also spent more days in hospital for reasons other than administration of chemotherapy (18.5 vs 14.4; p < 0.05). The number of days of chemotherapy was significantly greater in the lenograstim group than in the placebo group (19.4 vs 17.5; p < 0.001) because of shorter delays between chemotherapy cycles in the lenograstim group. The use of lenograstim to prevent chemotherapy-induced neutropenia in patients with NHL was associated with a reduction in total direct medical costs (excluding the cost of lenograstim) of FF7297 as a result of reduced patient morbidity. Furthermore, the higher rate of completion of chemotherapy in the lenograstim group may lead to better long term survival; this observation deserves further clinical investigation.

[Protective action of biphenyl dimethyl dicarboxylate (DDB) against liver nuclear DNA damage induced by carcinogens]

The protective effect of DDB against carcinogen-induced DNA damage was examined in the present investigation. Preincubation of rat liver nuclei with DDB (1 mmol/L) resulted in inhibition of binding of 3H-benzo (a) pyrene to nuclear DNA. The inhibition rate was about 60%. Unscheduled DNA synthesis (UDS) of freshly isolated rat hepatocytes induced by aflatoxin B1 (10(-7) mol/L) was also dose dependently inhibited by DDB (10(-6)-10(-3) mol/L). Oral administration of DDB at 200 mg/kg once daily for 3 days was effective to induce increase of liver cytosol glutathione-S-transferase and microsomal UDPG-transferase in mice. The results indicate that DDB is able directly or indirectly to antagonize certain carcinogen-induced DNA damages.

[[Protective action of biphenyl dimethyl dicarboxylate (DDB) against liver nuclear DNA damage induced by carcinogens]]

The protective effect of DDB against carcinogen-induced DNA damage was examined in the present investigation. Preincubation of rat liver nuclei with DDB (1 mmol/L) resulted in inhibition of binding of 3H-benzo (a) pyrene to nuclear DNA. The inhibition rate was about 60%. Unscheduled DNA synthesis (UDS) of freshly isolated rat hepatocytes induced by aflatoxin B1 (10(-7) mol/L) was also dose dependently inhibited by DDB (10(-6)-10(-3) mol/L). Oral administration of DDB at 200 mg/kg once daily for 3 days was effective to induce increase of liver cytosol glutathione-S-transferase and microsomal UDPG-transferase in mice. The results indicate that DDB is able directly or indirectly to antagonize certain carcinogen-induced DNA damages.

Sodium regulation in the affinity of renal alpha 2-adrenoceptors for epinephrine in Sabra salt-sensitive and salt-resistant rats

Sodium ions markedly decreased in vitro renal alpha 2-adrenoceptor affinity for epinephrine in Sabra hypertensive (SBH) but not in normotensive (SBN) rats. Under these conditions, affinity of alpha 1-adrenoceptor for epinephrine was unchanged in SBH and SBN rats. If these data could be confirmed in vivo, the sodium ion, by acting as an inhibitor, could modify the effect of agonists on renal alpha 2-adrenoceptors in SBH rats. Conversely, the absence of sodium regulation in SBN rats might represent a genetically mediated change responsible for the resistance to the development of salt-induced hypertension.

[Binding sites of imidazolines. Study with (3H)-idazoxan in renal cortex of Sabra salt-sensitive (SBH) and salt-resistant (SBN) rats]

Imidazoline binding sites have been characterized in organs modulating blood pressure, such as brain and kidney with (3H)-p-aminoclonidine and (3H)-Idazoxan respectively. However, the pharmacological characteristics of the imidazoline-preferring binding sites differ considerably depending on the species investigated and the radioligand used. Little is known about the physiological relevance of the non-adrenergic (3H)-idazoxan binding sites. As some imidazolines and certain alpha-adrenoceptor agonists possess antihypertensive activity, an alteration of these binding sites should be considered as a possible causes in the development of hypertension. In the present study, we performed binding studies with the imidazoline ligand (3H)-idazoxan in renal cortex of hypertensive salt-sensitive (SBH) and normotensive salt-resistant (SBN) Sabra rats. (3H)-idazoxan binding capacities were higher in SBH than in SBN rats. Competition studies have shown for (3H)-idazoxan specific binding non-adrenergic characteristics exclusively. In these both substrains, (3H)-idazoxan binding exhibit pharmacological profile of imidazoline binding sites. However, theses sites have also high affinity for guanidino compounds and amiloride. Surprisingly, amiloride and some analogues were significantly more potent in SBN than in SBH rats. From this study, it is difficult to elucidate the physiological role of imidazoline binding sites in renal cortex. However, differences observed between SBN and SBH suggest that these sites may play a role in the development of hypertension in Sabra rats.

Alpha-adrenoceptor properties in rat strains sensitive or resistant to salt-induced hypertension

Cerebral and renal alpha 2-adrenoceptors are implicated in the control of sympathetic activity and of sodium reabsorption respectively. In addition, sodium ions play an important role in the regulation of either alpha 2-adrenoceptor densities and affinities for adrenergic agonists. In the present study, alpha-adrenoceptor properties were investigated in genetically predetermined salt-sensitive and salt-resistant Dahl and Sabra rats. Cerebral alpha 2-adrenoceptor densities were higher in salt-resistant than in salt-sensitive Dahl and Sabra rats. In contrast, renal alpha 2-adrenoceptor density was higher in salt-sensitive than in salt-resistant rats. No difference in cerebral and renal alpha 1-adrenoceptor densities was observed between Dahl and Sabra substrains. Noradrenaline content in cerebral and renal cortex were also similar in both these rat substrains. Sodium ions markedly increased cerebral and renal high-affinity alpha 2-adrenoceptor densities in salt-sensitive but not in salt-resistant rats. Cerebral and renal alpha 1-adrenoceptor densities were unchanged in salt-sensitive and salt-resistant substrains of Dahl and Sabra rats. In addition, sodium ions reduced the affinity of adrenaline for renal alpha 2-adrenoceptors in salt-sensitive rats but not in salt-resistant rats. We can conclude that there exist genetically determined differences in the densities and properties of cerebral and renal alpha 2-adrenoceptors between salt-sensitive and salt-resistant rat strains. Abnormal densities of alpha 2-adrenoceptors may play a primary role in the role in the development of hypertension in salt-sensitive animals. These results also suggest an association between absence of sodium regulation of alpha 2-adrenoceptors and resistance to salt-induced hypertension. The absence of sodium regulation in salt-resistant rats may be linked either to a particular receptor conformation or to an abnormal structure of the receptor system. This property may represent a genetically-mediated change responsible for the resistance to the development of salt-induced hypertension.