Average IC50 Values Research Articles

Anti-Tumor Activity of ASTX029, a Dual Mechanism Inhibitor of ERK1/2, in Preclinical AML Models

Oncogenic mutations in genes such as the RAS family (KRAS, NRAS or HRAS) or receptor tyrosine kinases (RTKs) drive tumor growth through aberrant activation of the mitogen activated protein kinase (MAPK) signaling pathway. Acute myeloid leukemia (AML) patients frequently exhibit activating mutations in MAPK pathway members, such as NRAS and KRAS, suggesting that these malignancies may be driven by aberrant activation of the MAPK pathway. Targeting of the MAPK pathway has been clinically validated in solid tumors, with agents targeting BRAF and MEK approved for the treatment of BRAF-mutant melanoma. However, there is currently no approved therapy directly targeting activated RAS family members and resistance to MAPK pathway inhibitors is frequently associated with reactivation of MAPK signaling. ERK1/2 (ERK) is a downstream node in the MAPK pathway and therefore represents an attractive therapeutic target for inhibition of MAPK signaling in these settings. We have recently described in vivo anti-tumor activity in MAPK-activated solid tumor models following treatment with ASTX029, a highly potent ERK inhibitor developed using fragment-based drug design. ASTX029 has a distinctive ERK binding mode which confers dual mechanism inhibition of ERK, inhibiting both the catalytic activity of ERK and its phosphorylation by MEK. Here, we demonstrate that ASTX029 is also active in AML models and potently inhibits in vitro and in vivo MAPK signaling and growth in these models. Using a panel of 15 AML cell lines, we investigated sensitivity to ASTX029 in vitro. We observed that 8 cell lines bearing mutations leading to increased MAPK pathway signaling were sensitive to treatment with ASTX029 with an average IC50 value of 47 nM, in contrast to an average IC50 value of 1800 nM for cell lines without activating mutations. The phosphorylation of RSK, a direct substrate of ERK, was suppressed for up to 24 h following treatment with ASTX029 in vitro. We have previously demonstrated good oral bioavailability for ASTX029 and once daily dosing resulted in significant tumor growth inhibition in AML cell line xenograft models. To confirm target engagement in vivo, we examined MAPK signaling in xenograft tissue and observed inhibition of the phosphorylation of RSK and of ERK itself, consistent with the dual mechanism of action proposed for ASTX029. In summary, the ERK inhibitor, ASTX029, has potent activity against MAPK-activated tumor models, including AML models, and is now being tested in a Phase 1/2 clinical trial in advanced solid tumors (NCT03520075). These data highlight its therapeutic potential for the treatment of AML in patients with mutations leading to MAPK pathway activation and support further investigation in these patient populations. Disclosures Hindley: Astex Pharmaceuticals: Current Employment. Fazal:Astex Pharmaceuticals: Current Employment. Munck:Astex Pharmaceuticals: Current Employment. Martins:Astex Pharmaceuticals: Current Employment. Shah:Astex Pharmaceuticals: Current Employment. Wilsher:Astex Pharmaceuticals: Current Employment. Wallis:Astex Pharmaceuticals: Current Employment. Keer:Astex Pharmaceuticals, Inc.: Current Employment. Lyons:Astex Pharmaceuticals: Current Employment.

Antineoplastic property of Ashwagandha for Paclitaxel concomitant, can induce p53-mediated apoptosis: In vitro search for anti-proliferative phytogent

Ashwagandha (Withania somnifera L. Dunal) is an important and traditional medicinal herb found in India. It has been reported that, Ashwagandha has potential anti-proliferative as well as chemo-accelerative activity. The goal of this study was to investigate the most probable reason behind Ashwagandha’s anti-proliferative and chemo-accelerative activity. In addition, chromatographically isolate and chemically characterize some new compound which have antineoplastic property and find the mode of action of it. In vitro assays (MTT and Western blot) for anti-tumorigenic potentiality of the isolated drug were carried out on HT-29, KB and HeLa cell lines. In this experimental study, purification and chemical characterization (by UV, FT-IR, HPLC, LC-MS, 1H-NMR) of an anti-cancer drug has been found as Paclitaxel. MTT-assay shows an average IC50 value of the isolated Paclitaxel is 10 nM. Western blot data reveals there may be ROS-associated p53-MDM2-related cell proliferation and apoptosis by the drug’s in vitro effect.

Cyclic bridged analogs of isoCA-4: Design, synthesis and biological evaluation.

In this work, a series of cyclic bridged analogs of isocombretastatin A-4 (isoCA-4) with phenyl or pyridine linkers were designed and synthesized. The synthesis of the desired analogs was performed by the formation of nitro-vinyl intermediates, followed by a Cadogan cyclization. Structure activity relationship (SAR) study demonstrates the critical role of the combination of quinaldine as ring A, pyridine as the linker, and indole as ring B in the same molecule, for the cytotoxic activity. Among all tested compounds, compound 42 showed the highest antiproliferative activity against a panel of cancer cell lines with average IC50 values of 5.6nM. Also, compound 42 showed high antiproliferative activity against the MDR1-overexpressing K562R cell line; thus, it was 1.5- and 12-fold more active than the reference compounds, isoCA-4 and CA-4, respectively. Moreover, 42 displayed a strong antiproliferative activity against the colon-carcinoma cells (HT-29), which are resistant to combretastatin A-4 and isoCA-4, and it was found to be 8000-fold more active than natural CA-4. Compound 42 also effectively inhibited tubulin polymerization both invitro and in cells, and induced cell cycle arrest in G2/M phase. Next, we demonstrated that compound 42 dose-dependently caused caspase-induced apoptosis of K562cells through mitochondrial dysfunction. Finally, we evaluated the effect of compound 42 in human no cancer cells compared to the reference compound. We demonstrated that 42 was 73 times less cytotoxic than isoCA-4 in quiescent peripheral blood lymphocytes (PBLs). In summary, these results suggest that compound 42 represents a promising tubulin inhibitor worthy of further investigation.

Stealth cross-linked polymeric nanoparticles for passive drug targeting: a combination of molecular docking and comprehensive in vitro assay

Till date, several studies have reported magnetic drug targeting as well as passive drug delivery. In this study, the passive characteristic of PEGylated carriers with a neutral surface charge rather than chitosan (CS)-based nanoparticles (NPs) with a positive charge was proved using molecular docking. The complete and without flaw stealth CS-coated magnetic NPs (mNPs) loaded with an anticancer drug for intravenous drug delivery were prepared using a modified ionic-crosslinking method. The physicochemical properties of the prepared magnetic-CS NPs were characterized in detail. The transmission electron micrographs of NPs showed an uniform particle morphology with an average diameter of smaller than 10 nm. The average IC50 values of the drug in PEGylated NPs for MCF-7 and PC-12 cells were 44 and 72 µM, respectively. The fabricated stealth NPs can increase the cytotoxicity and cell permeability of formulation that may release the entire drug in targeted shape to objective tissues that were firstly proved by molecular docking. This strategy showed a reduction in uptaking of mNPs by the reticuloendothelial system, which indeed increases the concentration of therapeutic agent(s) in the target site.

Abstract 1917: The HDAC inhibitor panobinostat elicits preferential cytotoxic and antiproliferative effects in IDH mutant glioblastoma

Abstract Glioblastoma (GBM) is an incurable form of brain cancer with a median survival of ~15 months. Identification of a CpG Island Methylator Phenotype (CIMP) subtype of GBM (G-CIMP) represents a significant clinical discovery as these patients have an enhanced survival, with a median survival of 3 years. G-CIMP is characterized by a mutation in isocitrate dehydrogenase 1 or 2 (IDH1/2) which results in production of the oncometabolite 2-hydroxglutarate, an inhibitor of α-ketoglutarate-dependent DNA demethylases. This mutation occurs early in gliomagenesis and further results in aberrant DNA methylation and widespread transcriptional repression. Histone deacetylase (HDAC) enzymes are localized to methylated chromatin via methyl-binding domain (MBD) proteins, so we hypothesized that IDH mutant GBM exhibits enhanced reliance on HDAC activity, which is functionally significant to their cell proliferation and survival. Using a panel of 6 patient-derived cell lines grown in defined growth media, we show that G-CIMP is significantly more sensitive in vitro to the clinically approved pan histone deacetylase (HDAC) inhibitor panobinostat, with IDH mutant GBM cells exhibiting ~4 and ~10 fold lower IC/EC50 values in flow cytometric cell viability and apoptosis assays compared to IDH wild type (WT) GBM cells, respectively. For IDH mutant GBM, the average IC50 value was 13.5 nM for cell viability assays and the average EC50 value was 4.8 nM for apoptosis assays. Induction of cleaved caspase 3, a marker of apoptosis, was observed only in IDH mutant GBM cells when exposed to 10 nM panobinostat over 5 days. Analysis of proliferation via BrdU incorporation assays show that treatment with 10 nM panobinastat for 48 hours results in a 90% reduction in proliferation of IDH mutant GBM compared to only 25% reduction in IDH WT GBM cells. Molecular analysis via western blot shows that various acetylated chromatin marks, i.e. H3K14/18/27Ac, are preferentially upregulated in our IDH mutant GBM cell lines when exposed to 10 nM panobinostat for 48 hours. This was also supported by ELISA data showing that IDH mutant GBM cells have ~2 fold increase in histone H3 acetylation compared to IDH WT cells in response to 10 nM and 50 nM panobinostat. These data led us to perform a HDAC activity assay with nuclear extracts from our IDH WT and mutant GBM cells, but this assay showed no significant difference in basal HDAC activity. Overall, our results support a hypothesis where IDH mutant GBMs are more sensitive to panobinostat via preferential uptake of the drug. These data ultimately suggest that G-CIMP tumor cells display a profound sensitivity to the cytotoxic and antiproliferative effects mediated by exposure to the HDAC inhibitor panobinostat. These studies provide a strong foundation for future preclinical work evaluating the use of HDAC inhibitors as a personalized cancer therapy to treat G-CIMP. Citation Format: Thomas K. Sears, Kevin D. Woolard. The HDAC inhibitor panobinostat elicits preferential cytotoxic and antiproliferative effects in IDH mutant glioblastoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1917.

HPLC-DAD analysis of Hyssopus Cuspidatus Boriss extract and mensuration of its antioxygenation property

BackgroundHyssopus cuspidatus Boriss has been used as an important ethnomedicinal plant for long to eliminate phlegm, relieve cough and as well as having antibacterial, antioxygenation, and antitumor activities. In this study, the polyphenol contents, flavonoid contents, free radical scavenging assay and animal antioxygenation property assay of ethanol extract of H. cuspidatus were measured.MethodsThis study determined the total polyphenol and flavonoid contents in H. cuspidatus by UV-VIS. Caffeic, ferulic, and rosmarinic acids were measured using HPLC-DAD. Free radical scavenging assay of H. cuspidatus was studied by colorimetric method. Animal antioxygenation property assay of H. cuspidatus was studied with mice by biochemical assay kits.ResultsThe total polyphenol and flavonoid contents of H. cuspidatus in 2017, 2018, 2019 were determined and the contents of H. cuspidatus in 2019 was the highest. In addition, rosmarinic acid was the phenolic acid with the highest content in H. cuspidatus. Compared with those of DPPH free radical, hydroxyl free radical, and superoxide anion free radical, the scavenging ability of H. cuspidatus of ABTS free radical was stronger, the average IC50 value was 0.0245 mg/mL. In animal antioxygenation property experiment, the model group was successfully established with decreased activities of SOD, CAT, and GSH-px and increased content of MDA. The ethanol extract of H. cuspidatus increased the activities of SOD, CAT, and GSH-px and reduced the content of MDA. Each group of samples and the ascorbic acid positive control group showed significant differences in the results of free radical scavenging and animal antioxygenation property experiments (P < 0.05).ConclusionsThese results suggest that H. cuspidatus exerts an antioxygenation property, which can be attributed to the contents of total polyphenol and flavonoid. Given its strong antioxygenation property, H. cuspidatus can be used as a new natural antioxidant in food preservation and disease treatment.

Design, synthesis, and bioevaluation of pyrazolo[1,5-a]pyrimidine derivatives as tubulin polymerization inhibitors targeting the colchicine binding site with potent anticancer activities

A series of Pyrazolo[1,5-a]Pyrimidine analogs were designed and synthesized as novel tubulin inhibitors. Among them, compounds 1a and 1b showed the highest antiproliferative activity against a panel of cancer cell lines with average IC50 values of 24.8 nM and 28 nM, respectively. We determined the crystal structures of 1a and 1b in complex with tubulin and confirmed their direct binding to the colchicine site. Compounds 1a and 1b also effectively inhibited tubulin polymerization in vitro, induced cell cycle arrest in G2/M phase, and inhibited cancer cell migration. In addition, compound 1b exhibited high metabolic stability in human liver microsomes. Finally, 1b was highly effective in suppressing tumor growth in a B16–F10 mouse melanoma model without apparent toxicity. In summary, these results suggest that 1b represents a promising tubulin inhibitor worthy of further investigation.

Sensitization of head and neck squamous cell carcinoma to apoptosis by combinational SMAC mimetic and Fas ligand-Fc treatment in vitro

This study aimed to investigate the in vitro efficacy of three different SMAC mimetics for pro-apoptotic sensitization of HNSCC cells. We evaluated BV-6 in comparison to Birinapant and LCL161, for which pro-apoptotic sensitization effects have been demonstrated. Concentration-dependent response was measured for BV-6 in each cell line with an average IC50 value 8-fold lower than of aforementioned SMAC mimetics. Combination treatment of FasL (log2) and BV-6 (IC10) showed highly significant cell count reductions even in the lowest applied concentration in five cell lines (PCI-1: p = 0.0002, PCI-13: p = 0.0002, Detroit 562: p: p < 0.0001, FaDu: p < 0.0001, SCC-25: p = 0.0047). Synergistic effects (y < 1) were evident in eight out of 10 cell lines (PCI-1, PCI-9, PCI-13, PCI-68, Detroit 562, FaDu, SCC-25 and HaCaT). Annexin V assays revealed in nine cell lines very highly significant (p < 0.001) pro-apoptotic effects of BV-6. Western blots showed a heterogeneous IAP expression following SMAC mimetic treatment. Except for two cell lines, at least the cellular inhibitor of apoptosis protein 1 (cIAP1) was degraded in response to BV-6.For prospective targeted HNSCC therapy, this study identifies SMAC mimetics, particularly BV-6 as the compound with the highest pro-apoptotic potency, as promising antitumor agents.

Functionalised nanoformulation of Swertiamarin with enhanced stability and hemocompatibility: synthesis, characterisation and anticancer evaluation

ABSTRACT This study aimed to enhance the stability and compatibility of swertiamarin by loading it on amino-functionalised graphene oxide (GO) by ultrasonication. The nanoformulation showed a new peak in the FTIR spectrum (1658 cm−1) and a coupled peak in the UV-Vis spectrum implying CO-NH2 interaction between swertiamarin and functionalised GO. The SEM image revealed a sheet-like appearance with an average particle size of 252.38 ± 86.09 nm. The nanoformulation was non-haemolytic at 200 μg/mL (<5%) whereas swertiamarin was haemolytic at 50 μg/mL concentration. The freeze-dried samples exhibited good stability at normal storage condition. The formulation and the swertiamarin displayed similar anticancer activity against HepG2 cell lines with an average IC50 value of 110 ± 0.75 μg/mL, respectively. Hence, the functionalised GO can be considered as a compatible carrier for bioactive compounds which provides better hemocompatibility and stability.

Bufadienolide glycosides and bufadienolides from the whole plants of Helleborus lividus, and their cytotoxic activity

Cytotoxicity-guided fractionation of the MeOH extract of Helleborus lividus Aiton ex Curtis (Ranunculaceae) resulted in the isolation of five undescribed bufadienolide glycosides and two undescribed bufadienolides, along with three known compounds. Their structures were determined by detailed spectroscopic analysis and hydrolysis studies. The isolated compounds showed cytotoxicity against HL-60 human leukemia cells and A549 human lung adenocarcinoma cells, with IC50 values ranging from 2.20 ± 0.01 nM to 0.77 ± 0.01 μM. The undescribed compound 3β-[(O-β-d-glucopyranosyl-(1 → 4)-α-l-rhamnopyranosyl)oxy]-14β,16β-dihydroxy-5β-bufa-20,22-dienolide induced apoptosis in HL-60 cells via a mitochondria-dependent apoptotic pathway. The average IC50 values of bufadienolide monorhamnosides for HL-60 and A549 cells were 10–20 times lower than those for Na+/K+ ATPase, implying that they induce tumor cell death via a mechanism of action other than Na+/K+ ATPase inhibition.

AQ-4, a deuterium-containing molecule, acts as a microtubule-targeting agent for cancer treatment

The important physiological function of microtubules makes them an indispensable and clinically effective target of anti-tumor agents. Herein, we sought to design, synthesize, and evaluate a novel 4-anilinoquinazoline derivative and identify its anti-tumor activity in vitro and in vivo. The novel compound, N-(4-methoxyphenyl)-N-methyl-2-(methyl-d3)quinazolin-4-amine (AQ-4), was identified as a representative scaffold and potent microtubule-targeting agent. As a promising antimitotic agent, AQ-4 displayed remarkable anti-tumor activity with an average IC50 value of 19 nM across a panel of 14 human cancer cell lines. AQ-4 also exhibited nearly identical potent activities against drug-resistant cells, with no evidence of toxicity towards normal cells. A further target verification study revealed that AQ-4 targets the tubulin-microtubule system by significantly inhibiting tubulin polymerization and disrupting the intracellular microtubule spindle dynamics. According to the results of mechanism study, AQ-4 induced cell cycle arrest in the G2/M phase, promoting evident apoptosis and a collapses of mitochondrial membrane potential. The superior anti-tumor effect of AQ-4 in vivo suggests that it should be further investigated to validate its use for cancer therapy.

Recovery and stable persistence of chloroquine sensitivity in Plasmodium falciparum parasites after its discontinued use in Northern Uganda

BackgroundUsage of chloroquine was discontinued from the treatment of Plasmodium falciparum infection in almost all endemic regions because of global spread of resistant parasites. Since the first report in Malawi, numerous epidemiological studies have demonstrated that the discontinuance led to re-emergence of chloroquine-susceptible P. falciparum, suggesting a possible role in future malaria control. However, most studies were cross-sectional, with few studies looking at the persistence of chloroquine recovery in long term. This study fills the gap by providing, for a period of at least 6 years, proof of persistent re-emergence/stable recovery of susceptible parasite populations using both molecular and phenotypic methods.MethodsEx vivo drug-susceptibility assays to chloroquine (n = 319) and lumefantrine (n = 335) were performed from 2013 to 2018 in Gulu, Northern Uganda, where chloroquine had been removed from the official malaria treatment regimen since 2006. Genotyping of pfcrt and pfmdr1 was also performed.ResultsChloroquine resistance (≥ 100 nM) was observed in only 3 (1.3%) samples. Average IC50 values for chloroquine were persistently low throughout the study period (17.4–24.9 nM). Parasites harbouring pfcrt K76 alleles showed significantly lower IC50s to chloroquine than the parasites harbouring K76T alleles (21.4 nM vs. 43.1 nM, p-value = 3.9 × 10−8). Prevalence of K76 alleles gradually increased from 71% in 2013 to 100% in 2018.ConclusionThis study found evidence of stable persistence of chloroquine susceptibility with the fixation of pfcrt K76 in Northern Uganda after discontinuation of chloroquine in the region. Accumulation of similar evidence in other endemic areas in Uganda could open channels for possible future re-use of chloroquine as an option for malaria treatment or prevention.

Copper-Cysteamine Nanoparticles as a Heterogeneous Fenton-Like Catalyst for Highly Selective Cancer Treatment

Herein, for the first time, we report copper-cysteamine (Cu-Cy) nanoparticles having Cu1+ instead of Cu2+ as an efficient heterogeneous Fenton-like catalyst for highly selective cancer treatment. Initial measurements of Cu-Cy's hydroxyl radical generation ability show that it behaves as a Fenton-like reagent in the presence of H2O2 (100 μM) at pH 7.4, and that its Fenton-like activity is dramatically enhanced under acidic conditions (pH 6.5 and 5.5). Notably, Cu-Cy exhibits high stability and minimal copper release during the Fenton-like reaction, demonstrating its potency as a heterogeneous Fenton-like catalyst with a low cytotoxic effect. Through extensive in vitro studies, Cu-Cy NPs are found to generate a significantly higher level of ROS, thereby causing significantly more destruction to cancerous cells than to normal cells without the need for exogenous additives, such as H2O2. To the best of our knowledge, the average IC-50 value of Cu-Cy to cancer cells (11 μg/mL) is the lowest among reported heterogeneous Fenton-like nanocatalyst so far. Additionally, compared to cancer cells, Cu-Cy NPs display substantially higher IC-50 value toward normal cells (50 μg/mL), suggesting high selectivity. Overall, Cu-Cy NPs can participate in heterogeneous Fenton-like activity with elevated H2O2 under acidic conditions to produce significantly higher levels of hydroxyl radicals in cancer cells when compared to normal cells, resulting in selective cytotoxicity to cancer cells.

Synthesis of novel, DNA binding heterocyclic dehydroabietylamine derivatives as potential antiproliferative and apoptosis-inducing agents

Several dehydroabietylamine derivatives containing heterocyclic moieties such as thiophene and pyrazine ring were successfully synthesized. The antiproliferative activities of these thiophene-based Schiff-bases, thiophene amides, and pyrazine amides were investigated in vitro against Hela (cervix), MCF-7 (breast), A549 (lung), HepG2 (liver), and HUVEC (umbilical vein) cells by MTT assay. The toxicity of L1 −L10 (IC50 = 5.92− >100 μM) was lower than L0 (1.27 μM) and DOX (4.40 μM) in every case. Compound L1 had higher anti-HepG2 (0.66 μM), anti-MCF-7 (5.33 μM), and anti-A549 (2.11 μM) and compound L3 had higher anti-HepG2 (1.63 μM) and anti-MCF-7 (2.65 μM) activities. Both of these compounds were recognized with high efficiency in apoptosis induction in HepG2 cells and intercalated binding modes with DNA. Moreover, with average IC50 values of 0.66 and 5.98 μM, L1 was nine times more effective at suppressing cultured HepG2 cells viability than normal cells (SI = 9). The relative tumor proliferation rate (T/C) was 38.6%, the tumor inhibition rate was up to 61.2%, which indicated that L1 had no significant toxicity but high anti-HepG2 activity in vivo. Thus, it may be a potential antiproliferation drug with nontoxic side effects.

Köpeklerde Kanin Leishmaniasis Etkeni Leishmania tropica’da İlaç Dirençlerinin Araştırılması

Objective: Leishmaniasis is endemic in 98 countries, and poses risk to 1 billion people in the world. The infection caused by obligatory intracellular parasite Leishmania spp. in dogs is called Canine Leishmaniasis (CanL). In this study, it was aimed to detect the resistance status of Leishmania tropica strains isolated from dogs in our country against amphotericin B, meglumine antimoniate and sodium stibogluconate applied in leishmaniasis treatment. Method: Leishmania spp. promastigotes, taken out from the liquid nitrogen were first cultured in NNN media, then the growing isolates were transferred to RPMI-1640 medium and abundant amount of promastigotes were obtained. Isolates were genotyped using real-time polymerase chain reaction method with primers and probes specific to the ITS-1 region of Leishmania spp. and in five isolates that were found to be L. tropica causing CanL, resistance status against amphotericin B, meglumine antimoniate and sodium stibogluconate was investigated by hemocytometer and XTT methods. Results: The mean IC50 values were determined as 10.60 mg/ml for meglumine antimoniate, 0.1471 mg/ml for sodium stibogluconate, 0.0328 μM/ml for amphotericin B by hemocytometer method. Average IC50 values determined by XTT method were 10.48 mg/ml for meglumine antimoniate, 0.1470 mg/ml for sodium stibogluconate, 0.0326 μM/ml for amphotericin B. Conclusion: According to our data, while L. tropica strains which were isolated from CanL cases which are very rarely found causative agents in dogs, were not found to be resistant to amphoreticin B and sodium stibogluconate, parasite developed drug resistance against meglumine antimoniate. In future, this situation is thought to be a problem during treatment in human cutaneous leishmaniasis cases.

Antioxidant and Antidiabetic Activities of Flavonoid Derivative Compounds Isolated from Sclerocarya birrea Leaves

Sclerocarya birrea is one of many medicinal plants used in African traditional medicine for treatment of diabetes. Bioassay-guided fractionation of the ethanolic crude extract of the leaves of the plant species led to the isolation of a pure compound (CMP-1). The pure compound showed antioxidant and antidiabetic activities with average IC50 values of 1.04 mg/mL and 46 μg/mL, respectively that were well comparable to the crude extract and known standards compounds, ascorbic acid and quercetin. The spectroscopic profiling of the purified compound revealed a flavonoid derivative structural skeleton. The findings of the study suggested that the flavonoid derivative compounds play a major role towards the medicinal value of Sclerocarya birrea.

Abstract B008: NEO2734, a novel dual BET and P300/CBP bromodomain inhibitor, is more active in NUT midline carcinoma than single agent BET or P300/CBP inhibitors

Abstract Background: NUT midline carcinoma (NMC) is an aggressive subtype of poorly differentiated squamous cell carcinoma, occurring anywhere along the trunk or the head, most commonly along the midline. NMC is characterized by chromosomal translocation resulting in the fusion of the gene nuclear protein in testis (NUT) and bromodomain and extraterminal domain (BET) proteins (BRD2,3,4 and BRDT). The acquired bromodomain region tethers the BRD-NUT fusion protein to acetylated chromatin. The molecular mechanism by which BRD-NUT is involved in the generation of NMC is unclear, although it seems to be related to massive disruption of normal gene regulation at key cell type–specific genes. After binding to acetylated chromatin through bromodomains, the NUT moiety of the fusion protein strongly interacts with and recruits E1A interacting protein of 300 kDa (EP300/P300), initiating cycles of BRD-NUT/P300 recruitment and creating chromatin “megadomains” enriched in histone H3 lysine 27 acetylation (H3K27ac), a specific enhancer and super-enhancer histone mark. The creation of these domains activates transcription of adjacent genes that seem to be critical for the progression of NMC. As BET inhibitors have shown activity in NMC and P300 is important in its pathophysiology, we examined the pre-clinical activity of NEO2734 and NEO1132, novel dual BET and P300/CBP inhibitors (Giles et al Abs #2510 ESMO 2018), in NMC. Results:Considering the important roles of BET proteins and P300 in NMC, two NMC-cell lines (1015 and 14169, C. French: Brigham and Women’s Hospital) were treated with dual BET and P300/CBP inhibitors NEO2734 and NEO1131 (Epigene Therapeutics Inc), BET inhibitors JQ1 and iBET155 (GSK525762) (Sigma-Aldrich) and P300/CBP inhibitor CPI-637 (MedChem Express) for comparison. The average IC50 values of the two molecules were 44.04 nM and 130.73 nM respectively in 1015 cell line and 77.37 nM and 123.95 nM in 14169 cell line. For the two cell lines, the dual inhibitor NEO2734 was more potent than NEO1131, IBET155 and p300 inhibitors. The 14169 cell line, with a higher number of genetic lesions than the 1015 cell line, was more resistant to NEO2734 than the 1015 cell line. Conclusions: The dual inhibitor NEO2734 showed superior in vitroanti-proliferative activity in two NMC cell lines compared with single BET and p300 inhibitors. We also observed the presence of two different cell populations (adherent and suspension cells) in both NMC cell lines with adherent cells being more resistant to NEO2734, Differences in the responses to NEO2734 in NMC are being studied to molecularly identify biomarkers of resistance. These data support the inclusion of patients with NMC in clinical studies of NEO2734. Citation Format: Tian Tian, Marc Cosín, Francis Giles, Irene Braña, Elena Garralda, Sandra Peiró. NEO2734, a novel dual BET and P300/CBP bromodomain inhibitor, is more active in NUT midline carcinoma than single agent BET or P300/CBP inhibitors [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B008. doi:10.1158/1535-7163.TARG-19-B008

Abstract PR09: Phase 1 clinical safety and efficacy of ASN007, a novel oral ERK1/2 inhibitor, in patients with RAS, RAF or MEK mutant advanced solid tumors

Abstract Background: The oncogenic mitogen-activated protein kinase (MAPK) pathway is dysregulated in a broad range of cancers through mutations in BRAF, KRAS, NRAS, HRAS and MEK1 genes. ASN007 is a novel, potent and orally bioavailable inhibitor of ERK1/2 kinases (IC50 1-2nM) with a very long target residence time (550 min). Preclinical studies show strong anti-tumor activity in multiple RAS mutant xenograft and PDX models, irrespective of mutation subtype. ASN007 also maintains strong activity in BRAF mutant melanoma PDX models resistant to BRAF and MEK inhibition. Preclinical activity is seen with both intermittent as well as daily dosing. This is the initial report of ASN007 clinical data from this first-in-human Phase 1 Study. Methods: This Phase 1 trial evaluates ASN007 in patients (PS 0-1) with metastatic solid tumors refractory to standard therapies using an accelerated dose titration design for once daily (QD) and once weekly (QW) oral dosing (NCT03415126). Primary objectives in Part A (dose finding) include safety, tolerability, PK and PD to determine the Maximum Tolerated Dose (MTD). Part B (disease specific expansion) will evaluate clinical activity in cohorts of 15 patients each with tumors harboring specific mutations which include NRAS, HRAS, MEK1 and BRAF. Results: To date, 42 eligible patients (pts) were enrolled at dose levels ranging from 10mg to 80mg QD and 80 mg to 350mg QW. The respective MTDs are 40mg QD and 250mg QW. Reversible treatment-related adverse events (TRAEs) at 40mg QD (n=10) included rash ( 90%, Gr3 10%), nausea/vomiting (Gr1 30%), diarrhea (Gr1 30%), fatigue (20%, Gr3 10%) and central serous retinopathy (CSR) (30%, no G3) and at 250mg QW (n=9) included rash (33%, no Gr3), CSR (11%, Gr3 11%), blurred vision (44%, Gr3 11%), nausea/vomiting (33%, Gr3 11%) and diarrhea (33%, no Gr3). Dose limiting toxicities (DLTs) included Gr3 CSR at 60 and 80 QD, Gr3 rash at 80mg QD and Gr3 AST at 350mg QW. Durable clinical benefit was noted for 3 pts treated with QW ASN007 at doses 120 mg to 250 mg: a confirmed partial response (-57%) in a patient with HRAS-mutant salivary gland cancer for 5+ months, stable disease in KRAS mutant ovarian cancer for 9+ months and stable disease in BRAF V600E mutant thyroid cancer for 8+ months. Pharmacokinetic studies demonstrated dose dependent increase in the Cmax and AUC24 with both QD and QW dosing. QW dosing Cmax levels exceed average IC50 values more than &amp;gt;30-fold. Inter-subject variability was moderate (≤ 50%) and the elimination t1/2 was 10-15 hours. Conclusions: ASN007 is a selective oral inhibitor of ERK1/2 with a long target residence time. QD or QW dosing is feasible with expected reversible and manageable AE profile and dose dependent exposure. The dose of 250mg QW was selected for further development due to favorable tolerability and encouraging signs of clinical activity. Part B of the study is open to enroll patients with solid tumors harboring BRAF, MEK1, and RAS mutations. Updated clinical, safety, PK/PD and efficacy data will be presented. Citation Format: Anthony W. Tolcher, Ryan J. Sullivan, Drew W. Rasco, Zeynep Eroglu, Nehal Lakhani, Dana Kessler, Helen Usansky, Sanjeeva Reddy, Louis J. Denis, Filip Janku. Phase 1 clinical safety and efficacy of ASN007, a novel oral ERK1/2 inhibitor, in patients with RAS, RAF or MEK mutant advanced solid tumors [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr PR09. doi:10.1158/1535-7163.TARG-19-PR09

Synthesis of Trichodermin Derivatives and Their Antimicrobial and Cytotoxic Activities.

Trichothecene mycotoxins are recognized as highly bioactive compounds that can be used in the design of new useful bioactive molecules. In Trichoderma brevicompactum, the first specific step in trichothecene biosynthesis is carried out by a terpene cyclase, trichodiene synthase, that catalyzes the conversion of farnesyl diphosphate to trichodiene and is encoded by the tri5 gene. Overexpression of tri5 resulted in increased levels of trichodermin, a trichothecene-type toxin, which is a valuable tool in preparing new molecules with a trichothecene skeleton. In this work, we developed the hemisynthesis of trichodermin and trichodermol derivatives in order to evaluate their antimicrobial and cytotoxic activities and to study the chemo-modulation of their bioactivity. Some derivatives with a short chain at the C-4 position displayed selective antimicrobial activity against Candida albicans and they showed MIC values similar to those displayed by trichodermin. It is important to highlight the cytotoxic selectivity observed for compounds 9, 13, and 15, which presented average IC50 values of 2 μg/mL and were cytotoxic against tumorigenic cell line MCF-7 (breast carcinoma) and not against Fa2N4 (non-tumoral immortalized human hepatocytes).

Pd(II) and Pt(II) Metallacycles with Unsymmetrical Ylide: Antiproliferative Effects and Application in Electrocatalytic Oxidation of Methanol

AbstractNew Pd(II) and Pt(II) complexes are described in which the multidentate phosphorus ylides [Ph2P(CH2)nPPh2=C(H)C(O)C6H4‐p‐OCH3] (n=1, (Y1); n=2, (Y2)) act as P,C chelating ligands. The chelating ability of these ligands resulted in the formation of [MBr2{K2(P,C)‐Y1}] (M=Pd (1), Pt (2)); [MBr2{K2(P,C)‐Y2}] (M=Pd (3), Pt (4) complexes, which were investigated using physicochemical techniques. X‐ray diffraction studies of a single crystal of complex 2 confirmed the structure of the five‐membered ring. Owing to the redox activity of phosphorus‐ylide complexes, their electrocatalytic activity for the oxidation of methanol has been studied. All compounds were found to possess the anti‐proliferative potency against MCF‐7 (breast carcinoma), A549 (non‐small lung carcinoma) and AGS (gastric carcinoma) cell lines with average IC50 values in the range of 14.53 to 287.92 μM. In general, the compounds Y1, Y2, 2, and 3 displayed high anticancer activities compared to 1 and 4. The antioxidant activity of the compounds, which was estimated by 1, 1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) free radical scavenging, was moderate to strong with IC50 values in the range 0.18 to 0.59 mg mL−1.