Ting-Shou Chen

Effects of alpha-mangostin on the expression of anti-inflammatory genes in U937 cells.

Backgroundα-Mangostin (α-MG) is a main constituent of the fruit hull of the mangosteen. Previous studies have shown that α-MG has pharmacological activities such as antioxidant, antitumor, anti-inflammatory, antiallergic, antibacterial, antifungal and antiviral effects. This study aims to investigate the anti-inflammatory molecular action of α-MG on gene expression profiles.MethodsU937 and EL4 cells were treated with different concentrations of α-MG in the presence of 0.1 ng/mL lipopolysaccharide (LPS) for 4 h. The anti-inflammatory effects of α-MG were measured by the levels of tumor necrosis factor (TNF)-α and interleukin (IL)-4 in cell culture media, which were determined with enzyme-linked immunosorbent assay kits. The gene expression profiles of all samples were analyzed with a whole human genome microarray, Illumina BeadChip WG-6 version 3, containing 48804 probes. The protein levels were determined by Western blotting analyses.Resultsα-MG decreased the LPS induction of the inflammatory cytokines TNF-α (P = 0.038) and IL-4 (P = 0.04). α-MG decreased the gene expressions in oncostatin M signaling via mitogen-activated protein kinase (MAPK) pathways, including extracellular signal-regulated kinases (P = 0.016), c-Jun N-terminal kinase (P = 0.01) , and p38 (P = 0.008). α-MG treatment of U937 cells reduced the phosphorylation of MAPK kinase 3 / MAPK kinase 6 (P = 0.0441), MAPK-activated protein kinase-2 (P = 0.0453), signal transducers and activators of transcription-1 (STAT1) (P = 0.0012), c-Fos (P = 0.04), c-Jun (P = 0.019) and Ets-like molecule 1 (Elk-1) (P = 0.038).ConclusionThis study demonstrates that α-MG attenuates LPS-mediated activation of MAPK, STAT1, c-Fos, c-Jun and EIK-1, inhibiting TNF-α and IL-4 production in U937 cells.

Development of novel 3D-QSAR combination approach for screening and optimizing B-Raf inhibitors in silico.

B-Raf is a member of the RAF family of serine/threonine kinases: it mediates cell division, differentiation, and apoptosis signals through the RAS-RAF-MAPK pathway. Thus, B-Raf is of keen interest in cancer therapy, such as melanoma. In this study, we propose the first combination approach to integrate the pharmacophore (PhModel), CoMFA, and CoMSIA models for B-Raf, and this approach could be used for screening and optimizing potential B-Raf inhibitors in silico. Ten PhModels were generated based on the HypoGen BEST algorithm with the flexible fit method and diverse inhibitor structures. Each PhModel was designated to the alignment rule and screening interface for CoMFA and CoMSIA models. Therefore, CoMFA and CoMSIA models could align and recognize diverse inhibitor structures. We used two quality validation methods to test the predication accuracy of these combination models. In the previously proposed combination approaches, they have a common factor in that the number of training set inhibitors is greater than that of testing set inhibitors. In our study, the 189 known diverse series B-Raf inhibitors, which are 7-fold the number of training set inhibitors, were used as a testing set in the partial least-squares validation. The best validation results were made by the CoMFA09 and CoMSIA09 models based on the Hypo09 alignment model. The predictive r(2)(pred) values of 0.56 and 0.56 were derived from the CoMFA09 and CoMSIA09 models, respectively. The CoMFA09 and CoMSIA09 models also had a satisfied predication accuracy of 77.78% and 80%, and the goodness of hit test score of 0.675 and 0.699, respectively. These results indicate that our combination approach could effectively identify diverse B-Raf inhibitors and predict the activity.

Pharmacophore modeling and virtual screening to identify potential RET kinase inhibitors

Chemical features based 3D pharmacophore model for REarranged during Transfection (RET) tyrosine kinase were developed by using a training set of 26 structurally diverse known RET inhibitors. The best pharmacophore hypothesis, which identified inhibitors with an associated correlation coefficient of 0.90 between their experimental and estimated anti-RET values, contained one hydrogen-bond acceptor, one hydrogen-bond donor, one hydrophobic, and one ring aromatic features. The model was further validated by a testing set, Fischers randomization test, and goodness of hit (GH) test. We applied this pharmacophore model to screen NCI database for potential RET inhibitors. The hits were docked to RET with GOLD and CDOCKER after filtering by Lipinskis rules. Ultimately, 24 molecules were selected as potential RET inhibitors for further investigation.

Selecting Tyrosine Kinase Inhibitors for Gastrointestinal Stromal Tumor with Secondary KIT Activation-Loop Domain Mutations

Advanced gastrointestinal stromal tumors (GIST), a KIT oncogene-driven tumor, on imatinib mesylate (IM) treatment may develop secondary KIT mutations to confer IM-resistant phenotype. Second-line sunitinib malate (SU) therapy is largely ineffective for IM-resistant GISTs with secondary exon 17 (activation-loop domain) mutations. We established an in vitro cell-based platform consisting of a series of COS-1 cells expressing KIT cDNA constructs encoding common primary±secondary mutations observed in GISTs, to compare the activity of several commercially available tyrosine kinase inhibitors on inhibiting the phosphorylation of mutant KIT proteins at their clinically achievable plasma steady-state concentration (Css). The inhibitory efficacies on KIT exon 11/17 mutants were further validated by growth inhibition assay on GIST48 cells, and underlying molecular-structure mechanisms were investigated by molecular modeling. Our results showed that SU more effectively inhibited mutant KIT with secondary exon 13 or 14 mutations than those with secondary exon 17 mutations, as clinically indicated. On contrary, at individual Css, nilotinib and sorafenib more profoundly inhibited the phosphorylation of KIT with secondary exon 17 mutations and the growth of GIST48 cells than IM, SU, and dasatinib. Molecular modeling analysis showed fragment deletion of exon 11 and point mutation on exon 17 would lead to a shift of KIT conformational equilibrium toward active form, for which nilotinib and sorafenib bound more stably than IM and SU. In current preclinical study, nilotinib and sorafenib are more active in IM-resistant GISTs with secondary exon 17 mutation than SU that deserve further clinical investigation.

Novel azulene-based derivatives as potent multi-receptor tyrosine kinase inhibitors.

A series of azulene-based derivatives were synthesized as potent inhibitors for receptor tyrosine kinases such as FMS-like tyrosine kinase 3 (FLT-3). Systematic side chain modification of prototype 1a was carried out through SAR studies. Analogue 22 was identified from this series and found to be one of the most potent FLT-3 inhibitors, with good pharmaceutical properties, superior efficacy, and tolerability in a tumor xenograft model.

Design of novel FLT-3 inhibitors based on dual-layer 3D-QSAR model and fragment-based compounds in silico.

FMS-like tyrosine kinase 3 (FLT-3) is strongly correlated with acute myeloid leukemia, but no FLT-3-inhibitor cocomplex structure is available to assist the design of therapeutic inhibitors. Hence, we propose a dual-layer 3D-QSAR model for FLT-3 that integrates the pharmacophore, CoMFA, and CoMSIA. We then coupled the model with the fragment-based design strategy to identify novel FLT-3 inhibitors. In the first layer, the previously established model, Hypo02, was evaluated in terms of its correlation coefficient (r), RMS, cost difference, and configuration cost, with values of 0.930, 1.24, 106.45, and 16.44, respectively. Moreover, Fischers cross-validation test of data generated by Hypo02 yielded a 98% confidence level, and the validation of the testing set yielded a best r value of 0.87. The features of Hypo02 were separated into two parts and then used to screen the MiniMaybridge fragment compound database. Nine novel FLT-3 inhibitors were generated in this layer. In the second layer, Hypo02 was subjected to an alignment rule to generate CoMFA- and CoMSIA-based models, for which the partial least-squares validation method was utilized. The values of q(2), r(2), and predictive r(2) were 0.58, 0.98, and 0.76, respectively, derived from the CoMFA model with steric and electrostatic fields. The CoMSIA model with five different fields yielded values of 0.54, 0.97, and 0.76 for q(2), r(2), and predictive r(2), respectively. The CoMFA and CoMSIA models were used to constrain 3D structures of the nine novel FLT-3 inhibitors. This dual-layer 3D-QSAR model constitutes a valuable tool to easily and quickly screen and optimize novel potential FLT-3 inhibitors for the treatment of acute myeloid leukemia.

Abstract 5781: ITRI-260, a new azaazulenone class kinase inhibitor, induces complete tumor regression and prolongs survival in AML mice

The FMS-like tyrosine kinase-3 (FLT3) is a receptor tyrosine kinase with important roles in hematopoietic stem/progenitor cell survival and proliferation. FLT3 is over-expressed in the majority of acute myeloid leukemia (AML) and the presence of FLT3 active mutations is associated with poor prognosis, implicating FLT3 as a potential target for AML treatment. ITRI-260 is a new azaazulenone class kinase inhibitor that inhibited FLT3-ITD-dependent MV4-11 cell growth with IC50 of 21 nM and cellular phosphorylation with IC50 of 17 nM. In in vivo PK study, ITRI-260 showed favorable oral PK profiles. The maximum concentration of ITRI-260 was 700 nM after a single 100 mg/kg oral dosing in mice, with dose proportional exposure from 10 to 150 mg/kg. ITRI-260 showed therapeutic efficacy in a human AML orthotopic SCID mouse model, following a 100 mg/kg/qd oral dosing regimen. The treatment group showed 100% survival of animals at day 90 after tumor cell inoculation, while the vehicle control group showed 100% mortality. In the other study, ITRI-260 also increased survival in primary tumor cell engraftment model inoculated with cells isolated from sunitinib- and sorafenib-resistant AML patient. Through hERG assay with patch clamp technology, we found higher IC50 of ITIR-260 compared with sunitinib and MLN-518, which indicates that ITRI-260 might arise less cardiotoxic concern. In a 14-day subchronic toxicology study in mice, ITRI-260 was generally tolerated at 300 mg/kg/qd. The most prominent adverse effect appeared at 600 mg/kg/qd group is starry sky appearance in spleen, which is moderate and reversible. No specific clinical signs or body weight loss were attributed to the test article. In conclusion, the in vitro/in vivo PK/PD/toxicology studies have provided the basis for the clinical developmental potential of ITRI-260 in AML. The bridge studies from discovery to development such as CMC, GLP toxicology/safety pharmacology and pre-formulation are now in progress. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5781.

Abstract 728: Development of pharmacophore-based RET inhibitors for thyroid cancer therapy

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC The new therapeutic option is pivotal due to the restricted efficacy of current treatments (surgery, radioactive iodine treatment, and chemotherapy) in progressive thyroid carcinomas. Gain-of-function mutations of the receptor tyrosine kinase RET have been identified as driving oncogenic events in subsets of papillary and medullary thyroid cancers (PTC and MTC), but targeted therapy for RET-driven cancers is currently clinically unavailable. Some mulit-kinase inhibitors, such as sunitinib and vandetanib, which have shown efficacy against other neoplastic diseases, are being evaluated in clinical trials for thyroid cancer therapy. However, the anti-VEGFR activities of these mulit-kinase inhibitors have been considered to lead cardiotoxicity in some patients. Moreover, Ret mutation-associated resistance have been reported by some RET inhibitors in preclinical data. The “in silico model” was applied to design the specific RET target compounds through mapping the pharmacophore of RET ATP-binding pocket. Some novel scaffold compounds which fit the pharmacophore model were selected form ITRI library, and their anti-RET activities were evaluated by kinase assay. The in vitro anti-cell proliferation activities of the compounds to the TT cells (MTC specific cells) were demonstrated by MTT assay. From the screening of ITRI library, ITRI-305 showed the impressive anti-RET (IC50 ∼ 90 nM) and anti-cell proliferation (IC50 at low micro molar) activities and the activities are compatible to those of sunitinib and vandetanib. ITRI-305 also shows good solubility and favorable oral PK profiles. The xenograft study of TT cells with ITRI-305 is proceeding. In conclusion, a novel scaffold RET inhibitor, ITRI-305, with less potent VEGFR activity (anti-VEFGR IC50 ∼ 1 μM) is developed to overcome the cardiotoxicity and resistance problems which is caused by conventional RET inhibitors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 728.

Abstract 3356: A controversial study on well reported liver cancer stem cell marker

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Recent studies suggest that the presence of cancer stem cells (CSC) could be linked with patients’ survival. The ability of cancers to grow indefinitely has fueled the idea that cancer and stem cells may have common underlying mechanisms. It has been suggested that tumors are initiated from cancer stem cells (CSCs) with proliferation potential drives the growth of cancer. CSCs are resistant to chemotherapy and radiation. However, the suggested cancer stem cell markers in human hepatocellular carcinoma cells are variable and confused. In this study, we profiled some of the most reported CSC markers, including CD133, epithelial cell adhesion molecule (EpCAM), aldehyde dehydrogenase (ALDH), CD90, CD24, c-kit, global-H and stemness genes in eight human hepatocellular carcinoma cell lines. Through specific marker expressed cell sorting by FACs aria or magnetic beads, the CSC associated drug resistance and tumorigenicity were further evaluated. However, there is no obvious difference among parental group, marker-positive group and marker-negative group in these CSC characteristics evaluated. It seems no good correlation between reported markers in liver cancer stem cells. Therefore, presence of markers alone should be taken with caution as single prognostic parameters. Through harsh culture condition, spheroid cell grew and had been isolated, which perform CSC-like properties. Moreover, forced activation of an ESC-like gene expression program can reprogram HCC cells into CSC-like cells and achieve pathologic self-renewal. The ability to create induced cancer stem cells (iCSC) may provide opportunities to better define the biology of cancer stem cells in order to trace or eliminate them in human patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3356.

Abstract LB-160: ITRI-260, a promising candidate for treatment of acute myeloid leukemia

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Acute myeloid leukemia (AML) is a highly malignant hematopoietic tumor characterized by an abnormal proliferation of myeloid progenitor cells, decreased rate of self-destruction and an arrest in cell differentiation. The internal tandem duplication mutations of FMS-like tyrosine kinase-3 (FLT3/ITD mutations) are common in AML and linked to poor prognosis. ITRI-260 generated from designed by computer-assisted rationale drug design and in silico prioritized approaches, was proved to be a potent cell growth inhibitor against FLT3/ITD mutated AML cells through FLT3 and c-Kit inhibition. The in vivo efficacy of ITRI-260 via oral route was demonstrated in MV4-11 xenograft mice model. Besides, two more orthotopic murine models were used to assess the in vivo therapeutic efficacy of ITRI-260. The first one is MV4-11 cell orthotopically engraft into NOD/SCID mice bone marrow and the second one is primary AML cells from AML patient engraft into NOD/SCID mice bone marrow. The results show that ITII-260 can decrease FLT3/ITD mutant leukemia blasts in peripheral blood and bone marrow in both animal models. Finally, ITRI-260 prolongs the survival in both bone marrow engraft mice models. These findings strongly suggest clinical benefits of ITRI-260 in patients with FLT3/ITD AML. Currently we are planning the bridged projects to push ITRI-260 toward IND status. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-160.