In this study, we describe the evaluation of a cell-based protein stability assay using β-galactosidase fragment complementation technology performed in two independent laboratories. The assay is based on the ability of certain ligands to bind to a protein leading to a ligand-protein complex that has a different stability than the free protein. The assay employed a prolabeled-tagged MEK1 kinase stably expressed in A549 cells and this was used to evaluate focused sets of compounds containing known MEK1inhibitors as well as a random set of compounds. An assay using a prolabeled-tagged lysine methyltransferase known as G9a expressed in A549 cells was used as a counterscreen. In one study, it was found that the majority of MEK1 inhibitors were either found as inactive (52%) or showed a selective inhibitory response (18%) in the cell-based MEK1 assay; however, eight compounds showed a specific activation response consistent with stabilization of MEK1 in cells. Examination of these stabilizing compounds showed that three of these were analogs of hypothemycin, a known covalent allosteric MEK1 inhibitor, while the remaining compounds covered one structural class. Both laboratories were able to confirm activity in the cell-based MEK1 assay for known MEK1 inhibitors and found that this activity was highly selective over the G9a counterscreen assay. Screening of a mechanism of action library containing compounds with bioactivity annotations against the cell-based MEK1 assay did not reveal any mechanisms leading to an increase in signal other than inhibitors of MEK1. This study supports that the MEK1 cellular protein stability assay is sensitive to certain MEK1 inhibitors, often noncompetitive inhibitors with respect to ATP. The cellular stability assay format could be useful to rapidly filter kinase inhibitor hit lists for allosteric kinase inhibitors and support target engagement in cells.

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To evaluate the safety and efficacy of the combination therapy of fluorouracil, leucovorin and irinotecan (FOLFIRI) and aflibercept in Asian patients with metastatic colorectal cancer (mCRC), who had progressed after oxaliplatin-based chemotherapy.
This is a retrospective analysis of 19 mCRC patients who received FOLFIRI and aflibercept (4 mg/kg intravenously) every 2 weeks via a Named Patient Program (supported by Sanofi Aventis) in Singapore. Treatment was administered until disease progression or unacceptable toxicities. Kaplan-Meier method was used to estimate progression-free survival (PFS) and overall survival (OS). Efficacy and toxicities were summarized using descriptive statistics. Statistical analysis was performed using STATA 12.0 software.
The majority (84%) of the patients were of chinese ethnicity. The median age was 59 years, with 63.2% of the patients having an Eastern Cooperative Oncology Group status of 1. Four patients (21.1%) achieved partial response and 8 patients (42.1%) achieved stable disease. After a median follow-up of 9.6 months [95% confidence interval (CI), 2.2-13.1 months], the median OS was 11.6 months (95% CI, 6.1 to not-estimable), and median PFS was 4.1 months (95% CI, 2.2-5.9). Majority of the toxicities were grade 1-2, and include leucopenia (84.2%), anemia (73.7%), liver enzyme elevation (68.4%) and fatigue (68.4%). The most frequently reported grade 3 toxicities were neutropenia and neutropenic complications (both 15.8%). All adverse events resolved with supportive management.
The clinical benefit and safety profile of the combination of FOLFIRI/aflibercept in Asian patients with mCRC are consistent with that of Western population. FOLFIRI/aflibercept may be an appropriate therapeutic option in Asian patients with mCRC previously treated with an oxaliplatin-based regimen.
© 2016 John Wiley & Sons Australia, Ltd.

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Cancerous cells have an acutely increased demand for energy, leading to increased levels of human glucose transporter 1 (hGLUT1). This up-regulation suggests hGLUT1 as a target for therapeutic inhibitors addressing a multitude of cancer types. Here, we present three inhibitor-bound, inward-open structures of WT-hGLUT1 crystallized with three different inhibitors: cytochalasin B, a nine-membered bicyclic ring fused to a 14-membered macrocycle, which has been described extensively in the literature of hGLUTs, and two previously undescribed Phe amide-derived inhibitors. Despite very different chemical backbones, all three compounds bind in the central cavity of the inward-open state of hGLUT1, and all binding sites overlap the glucose-binding site. The inhibitory action of the compounds was determined for hGLUT family members, hGLUT1-4, using cell-based assays, and compared with homology models for these hGLUT members. This comparison uncovered a probable basis for the observed differences in inhibition between family members. We pinpoint regions of the hGLUT proteins that can be targeted to achieve isoform selectivity, and show that these same regions are used for inhibitors with very distinct structural backbones. The inhibitor cocomplex structures of hGLUT1 provide an important structural insight for the design of more selective inhibitors for hGLUTs and hGLUT1 in particular.

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c-KIT kinase is a validated drug discovery target for gastrointestinal stromal tumors (GISTs). Clinically used c-KIT kinase inhibitors, i.e., Imatinib and Sunitinib, bear other important targets such as ABL or FLT3 kinases. Here we report our discovery of a more selective c-KIT inhibitor, compound 13 (CHMFL-KIT-110), which completely abolished ABL and FLT3 kinase activity. KinomeScan selectivity profiling (468 kinases) of 13 exhibited a high selectivity (S score (1) = 0.01). 13 displayed great antiproliferative efficacy against GISTs cell lines GIST-T1 and GIST-882 (GI50: 0.021 and 0.043 μM, respectively). In the cellular context, it effectively affected c-KIT-mediated signaling pathways and induced apoptosis as well as cell cycle arrest. In addition, 13 possessed acceptable bioavailability (36%) and effectively suppressed the tumor growth in GIST-T1 cell inoculated xenograft model without apparent toxicity. 13 currently is undergoing extensive preclinical evaluation and might be a potential drug candidate for GISTs.

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On April 15, 2016 Lytix Biopharma reported that Lytix Biopharma presented 4 posters at AACR (Free AACR Whitepaper) in New Oreleans April 2016 (Press release, Lytix Biopharma, APR 15, 2016, View Source [SID:1234514845]).

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Andrew Saunders (CMO), Øystein Rekdal (CSO), Baldur Sveinbjørnsson (Senior researcher), Ketil Camilio (Senior researcher) and Brynjar Mauseth (PhD Student) represented Lytix Biopharma at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) in New Orleans April 16-21, 2016. Leading scientists and a large number of pharmaceutical companies attends the conference, and the mission is to prevent and cure cancer through research, education, communication and collaboration.

Together with scientific collaborators at Institut Gustav Roussy, Oslo University Hospital and University of Tromsø Lytix Biopharma presented 4 posters at the conference:

Sunday April 17, 2016:
Enhanced antitumor activity achieved by combining the oncolytic peptide LTX-315 with anti-PD-L1 antibody
Monday April 18, 2016:
LTX-315, an oncolytic peptide, increases anticancer immunity mediated by CTLA4 blockade in an interleukin-2 receptor beta-chain-dependent manner
The amphiphatic ß(2,2)-amino acid LTX-401 induces complete regression of experimental hepatocellular carcinoma
Wednesday April 20, 2016:
The oncolytic peptide LTX-315 enhances tumor-specific immune responses and tumor regression in murine 4T1 breast cancer when combined with doxorubicin