IC50 For Inhibition Research Articles

CTNI-41. PHASE II AND PHASE 0 RESULTS OF ABTC 1801: A MULTI-ARM CLINICAL TRIAL OF THE PARP INHIBITOR PAMIPARIB WITH VERY LOW DOSE METRONOMIC TEMOZOLOMIDE IN RECURRENT IDH MUTANT GLIOMAS

Abstract BACKGROUND Preclinical studies have demonstrated that IDH1-mutant (IDHmt) gliomas harbor a BRCAness phenotype with a defect in homologous recombination that confers PARP inhibitor sensitivity. METHODS The phase II component of ABTC 1801 examined the efficacy of the combination of pamiparib (BeiGene BGB-290) with low dose metronomic temozolomide in recurrent IDHmt grade 2 and 3 gliomas. In this two-stage design, Arm A enrolled patients who had failed two lines and Arm B a single line of alkylator therapy. Pamiparib and temozolomide doses based on phase I results was 60 mg BID and 20 mg daily. Primary endpoint was objective response rate (ORR). RESULTS 39 patients (Arm A 15, Arm B 24) enrolled in the phase II. Median age was 45 (range: 25-69), 56% male, and median KPS 90. 72% of tumors were MGMT methylated. There were no confirmed responses in Arm A and one in Arm B; neither arm met the threshold for additional accrual. One-third of subjects discontinued treatment for reasons other than progressive disease. Estimated median PFS was 5.8 months in Arm A and 11.3 months in Arm B. Seven subjects (Arm A 3, Arm B 4) developed DLT during treatment. Grade 3+ toxicity was principally hematologic; 9 patients had grade 3 anemia, 7 grade 3 and 3 grade 4 neutropenia, and 3 grade 3 thrombocytopenia. In enhancing and non-enhancing tumors from 8 surgical arm patients, median unbound drug tumor/plasma ratios were 0.98 and 0.92, respectively; and median unbound pamiparib tumor concentrations were 209 and 188 nmol/L (or nmol/kg), respectively, which were >20-fold the in vitro IC50 for PARP inhibition. CONCLUSIONS While pamiparib appeared to achieve sufficient pharmacologically active concentrations in both enhancing and non-enhancing tumors, combination with temozolomide did not produce a meaningful ORR in IDHmt recurrent gliomas. Cumulative hematologic toxicity was substantial.

In Vitro Anti-inflammatory Activity of Bamboo Tali Leaf (Gigantochloa apus) Ethanol Extract

Inflammation is a physiological process that serves as a defense mechanism for the body against foreign substances, bacteria, or irritants. Inflammation can be cured with anti-inflammatory drugs. One of the plants that has the potential to be an anti-inflammatory agent is the bamboo leaf. This research aims to analyze the content of secondary metabolites, determine the inhibition value and IC50 value of the anti-inflammatory activity of the ethanol extract of bamboo tali leaves. Bamboo tali leaves were macerated using 96% ethanol and subjected to phytochemical screening. The extract was then tested for anti-inflammatory activity in vitro with the Bovine Serum Albumin (BSA) protein denaturation inhibition method. Bamboo tali leaf ethanol extract contains flavonoids, alkaloids, saponins, and phenols. The anti-inflammatory activity of the ethanol extract of bamboo tali leaves with concentrations of 28, 42, 56, 70, and 84 ppm had an inhibition percentage value of 23.14 ± 0.008%; 34.30 0.026%; 54.51 0.060%; 69.07 ± 0.006%; and 87.02 ± 0.021% with an IC50 value of 52.991 ppm. These results indicate that the ethanol extract of bamboo tali leaves has the potential to be an anti-inflammatory with a strong IC50 value below 100 ppm.

Anticancer Studies of Newly Synthesized Thiazole Derivatives: Synthesis, Characterization, Biological Activity, and Molecular Docking

Thiazole and its derivatives have received a lot of attention from researchers due to its wide biological, pharmacological, and anticancer properties. A novel series of 2-[2-[4-Hydroxy-3-substituted benzylidene hydrazinyl]-thiazole-4[5H]-ones (4a–c) and acetoxy derivative (5) were synthesized via using thiosemicarbazones (2a–c). The structure of the thiazole derivatives (4a–c) and 5 in these compounds was confirmed by spectroscopic techniques (IR and NMR), as well as elemental investigations. The synthesized derivatives biological activity was assessed based on their capacity to suppress the growth of the cancer cell lines MCF-7 and HepG2, as well as to halt the cell cycle and trigger apoptosis. Among the synthesized thiazole derivatives, compound 4c was found the most active derivative, with inhibitory concentrations IC50 = 2.57 ± 0.16 and 7.26 ± 0.44 µM in MCF-7 and HepG2, respectively, compared to Staurosporine as the standard drug with IC50 6.77 ± 0.41 and 8.4 ± 0.51 µM, respectively. Additionally, compound 4c blocked vesicular endothelial growth factor receptor-2 (VEGFR-2), according to our results (IC50 = 0.15 µM), compared to Sorafenib (IC50 = 0.059 µM) as the standard drug. Moreover, compound 4c induced cell cycle arrest at the G1/S phase, increasing the percentage and accumulation of cancer cells (DNA content) in the pre-G1 phase by 37.36% in MCF-7 cancer cells compared to untreated MCF-7 cells at 2.02%. Also, compound 4c increased the percentage of early and late apoptosis from 0.51% and 0.29%, respectively, in the case of the MCF-7 untreated control sample to 22.39% and 9.51%, respectively, in the MCF-7 treated sample. Furthermore, molecular docking studies of compounds 4a–c and 5 were conducted with four key proteins (aromatase, epidermal growth factor receptor (EGFR), cyclin-dependent kinase 2 (CDK2), and B-cell lymphoma 2 (Bcl-2)) that stimulate the growth, proliferation, and development of cancer cells. Compound 4c exhibited good docking scores with a promising and potential binding affinity toward the active site of selected docked proteins. According to these results, compound 4c showed efficient cytotoxic activity against the tested cancer cells.

Exploring the structural-activity relationship of hexahydropyrazino[1,2-d]pyrido[3,2-b][1,4]oxazine derivatives as potent and orally-bioavailable PARP7 inhibitors

PARP7 has emerged as a promising anti-tumor target due to its crucial roles in nucleic acid sensing and immune regulation. Herein, we explored the structural-activity relationship of tricyclic PARP7 inhibitors containing a hexahydropyrazino[1,2-d]pyrido[3,2-b][1,4]oxazine motif. The effects of the chirality of the fused rings, the group conjugated to the fused rings, and the size of the linker on PARP7 inhibition were fully investigated. Our work leads to the discovery of an extremely potent and orally-bioavailable PARP7 inhibitor, namely 18 (PARP7 inhibition IC50 = 0.56 nM), for efficacious treatment of lung cancer in vivo. Notably, 18 showed acceptable bioavailability in ICR mice (F = 33.9%) and Beagle dogs (F = 45.2%). Further investigation of ADME-T properties suggested that 18 has the potential to be developed as a candidate drug molecule for PARP7-sensitive tumors.

Biological Evaluation of Xanthene and Thioxanthene Derivatives as Antioxidant, Anticancer, and COX Inhibitors.

Xanthene and thioxanthene analogues have been investigated for their potential as anticancer and anti-inflammatory agents. Additionally, cysteine analogues have been found to possess antioxidant, anti-inflammatory, and anticancer activities due to their role in cellular redox balance, scavenging of free radicals, and involvement in nucleophilic reactions and enzyme binding sites. In this study, we synthesized a library of tertiary alcohols derived from xanthene and thioxanthene, and further, some of these compounds were coupled with cysteine. The objective of this research was to explore the potential anticancer, antioxidant, and anti-inflammatory activities of the synthesized compounds. The synthesized compounds were subjected to test for anticancer, antioxidant, and anti-inflammatory activities. Results indicated that compound 3 exhibited excellent inhibition activity (IC50 = 9.6 ± 1.1 nM) against colon cancer cells (Caco-2), while compound 2 showed good inhibition activity (IC50 = 161.3 ± 41 nM) against hepatocellular carcinoma (Hep G2) cells. Compound 4 demonstrated potent antioxidant inhibition activity (IC50 = 15.44 ± 6 nM), and compound 7 exhibited potent anti-inflammatory activity with cyclooxygenase-2 (COX-2) inhibition IC50 (4.37 ± 0.78 nM) and high selectivity for COX-2 (3.83). In conclusion, certain synthesized compounds displayed promising anticancer activity and anti-inflammatory effects. Nevertheless, additional research is necessary to create more analogues, develop a more distinct comprehension of the structure-activity relationship (SAR), and perform in vivo experiments to evaluate the pharmacokinetic and pharmacodynamic characteristics of the compounds under examination. Such research may pave the way for the development of novel therapeutic agents with potential applications in cancer and inflammatory diseases.

Erica arborea Bitkisi Kullanılarak Sentezlenen Çinko Nanopartiküllerin Biyoaktivitesinin Değerlendirilmesi

The synthesis of nanoparticles by environmentally friendly, cost-effective and simple methods has been the subject of much research in medicine and industry. In particular, it offers a promising approach for the development of next-generation nano-based drugs. This study synthesized zinc oxide nanoparticles (ZnO NPs) using Erica arborea (E. arborea) leaf extract as a stabilizing and reducing agent. The prepared ZnO NPs were characterized by UV-vis, FTIR and SEM-EDX analysis. SEM-EDX analysis showed that the nanoparticles were spherical in shape and showed strong signals of zinc metal. UV-vis analysis confirmed that the color of the solution changed to light yellow, indicating the formation of nanoparticles, and exhibited an absorption peak at 350 nm. FT-IR confirmed that the formation of nanoparticles was accompanied by metabolites of the leaf extract. The pharmacological potential of zinc nanoparticles synthesized by E. arborea was evaluated by antioxidant (DPPH method), antimicrobial (disk diffusion method) and lipid peroxidation (TBA method) activities. The biosynthesized ZnO NPs exhibited better antioxidant activity compared to the plant extract. The IC50 values of DPPH radical scavenging activity of ZnO NPs and leaf extract were 18.71±0.35 and 9.21±0.10, respectively. The lipid peroxidation inhibitory activity IC50 value of ZnO NPs was found to be 5.33±0.09. ZnO NPs were found to be sensitive against pathogenic bacteria P. aeruginosa, B. cereus, B. subtilis and S. aureus and fungal strain C. albicans. The findings suggest that synthesizing naturally synthesized zinc nanoparticles could be an alternative agent to physical and chemical methods. In addition, the pharmacological activity of nanoparticles will contribute to next-generation drug development studies.

The Study of the Phenolic compounds, Antioxidant activity and Antibacterial effect of Herbal Ethanol extracts of Scorzonera purpurea subsp. rosea

The increased demand for medicinal products of natural origin causes the search for new plants with a certain spectrum of pharmacological action. Scorzonera purpurea subsp. rosea is a one of unexplored plants in the phytochemical and pharmacological sense. The aim of this research was to evaluate the phenolic compounds, antioxidant activity and antibacterial effect of ethanolic extracts of Scorzonera purpurea subsp. rosea (EE-Sp). The results of the study of EE-Sp which contained 70% of ethanol (E70) showed the high content of phenolic compounds (2.111mg/mL), flavonoids (0.276mg/mL) and anti-radical activity of 86%, which was determined by the DPPH method, its effective concentration of inhibition IC50 - 0.67mg/mL as well as the strong ferric reducing potential (FRAP method) - 23.58μmol/mL.The HPLC method was used to identify chlorogenic, caffeic, ferulic, rosmarinic acids, luteolin, quercetin, apigenin, apigenin-7-glucoside, and rutin. Chlorogenic acid, luteolin and apigenin were the dominant substances in terms of quantity. Studies of the antibacterial effect of the extract E70 with respect to the test-strains of bacteria Staphylococcus aureus ATCC 25923, Escherichia coli dH5a, Pseudomonas aeruginosa ATCC 9027 showed the effectiveness of the extract compared to control.

Synthesis of 1,3,5-triphenyl-1,2,4-triazole derivatives and their neuroprotection by anti-oxidative stress and anti-inflammation and protecting BBB

Acute ischemic stroke (AIS) is a serious cardiovascular and cerebrovascular disease; Oxidative stress and neuroinflammation are important factors which destroy blood-brain barrier (BBB) in AIS. In the study, a series of 1,3,5-triphenyl-1,2,4-triazole derivatives were designed and synthesized; the optimal compound 9 was obtained by screening their anti-oxidant and anti-inflammatory effects; the neuroprotection effect of compound 9 was evaluated with a rat middle cerebral artery occlusion (MCAO) model. Subsequently, the mechanism of neuroprotection were explored via Western blot. The results prompt compound 9 maybe exert anti-AIS neuroprotection by inhibiting oxidative stress and neuroinflammation inhibition by inhibiting Keap1, COX-2 and iNOS. At the same time, it can protect BBB by reducing glycocalyx degradation and matrix metallopeptidase-9 levels. Its LD50 > 1000 mg/kg on mice and hERG channel inhibition IC50 > 30 μM, which lower acute toxicity and hERG channel inhibition would make compound 9 a promising stroke treatment candidate.

HYPOGLYCEMIC POTENTIAL OF HIBISCUS ROSA-SINENSIS AND MANGIFERA INDICA LEAVES BY IN VITRO METHODS

Objective: The objective of the present study was to provide in vitro evidence for the potential inhibitory activity of extracts of Mangifera indica (MI) and Hibiscus rosa-sinensis on α-amylase and α-glucosidase enzymes. Methods: The plant extracts were prepared with methanol by maceration. Different concentrations (10, 20, 40, 80, and 100 μg/mL) of both the extracts were made using distilled water, and the extracts were subjected to α-amylase and α-glucosidase inhibitory assay. The absorbance was measured at 540 nm and 405 nm using spectrophotometer. Using this method, the percentage of α-amylase and α-glucosidase inhibitory activity and IC50 values of each extract were calculated. Results: The methanolic extracts of MI and H. rosa-sinensis exhibited significant α-amylase and α-glucosidase inhibitory activity. The inhibitory effect of α-amylase inhibitory assay was observed up to 89% and 90% at a concentration of 100 μg/mL in MI and H. rosa-sinensis, respectively. The inhibitory effect of α-glucosidase inhibitory assay was observed up to 89% and 91% at a concentration of 100 μg/mL in MI and H. rosa-sinensis, respectively, and is comparable to the standard acarbose (94% at 100 μg/mL). The IC50 values of α-amylase inhibitory assay of MI and H. rosa-sinensis are 35.33 and 30.97, respectively. The IC50 values of α-glucosidase inhibitory assay of MI and H. rosa-sinensis are 31.67 and 25.86, respectively. The IC50 value of acarbose is 6.94. Conclusion: The results obtained support that MI and H. rosa-sinensis extracts exhibit considerable α-amylase and α-glucosidase inhibitory activity which can be attributed to the phytochemical constituents present in them. Further, this study supports its usage in ethno medicines for the management of diabetes.

Protease inhibitors characterisation by SDS-PAGE and MALDI-TOF from Alocasia macrorrhizos and their modulation of macrophage immune-inflammatory properties

This study describes the extraction and identification by electrophoretic and spectrometric techniques of protease inhibitor from the medicinal plant Alocasia macrorrhizos as well as investigates their immunomodulatory properties and cell viability. The A. macrorrhizos tubers were subjected to protease inhibitor extractions and characterised using SDS-PAGE and MALDI-TOF. The protein extracts were assessed for activities trypsin inhibition stoichiometry, haemagglutinating, cell viability, NO and TNF-α production inhibition. Concerning the protease inhibitors analysis through SDS-PAGE, the results showed two bands with 11 and 24 kDa, and the MS analysis detected the ions more intense of m/z 4276.795 and 8563.361 in the roasted protein extract. The IC50 of trypsin inhibition was 0.119 and 0.302 mg L−1 in the roasted and crude tuber, respectively. The protease inhibitors extract from the roasted tubers showed a reduction in the production of NO and TNF-α at concentrations lower than 100 µg mL−1, without a reduction in cell viability.

Suppression of superoxide/hydrogen peroxide production at mitochondrial site IQ decreases fat accumulation, improves glucose tolerance and normalizes fasting insulin concentration in mice fed a high-fat diet.

We developed S1QEL1.719, a novel bioavailable S1QEL (suppressor of site IQ electron leak). S1QEL1.719 prevented superoxide/hydrogen peroxide production at site IQ of mitochondrial complex I in vitro. The free concentration giving half-maximal suppression (IC50) was 52nM. Even at 50-fold higher concentrations S1QEL1.719 did not inhibit superoxide/hydrogen peroxide production from other sites. The IC50 for inhibition of complex I electron flow was 500-fold higher than the IC50 for suppression of superoxide/hydrogen peroxide production from site IQ. S1QEL1.719 was used to test the metabolic effects of suppressing superoxide/hydrogen peroxide production from site IQin vivo. C57BL/6J male mice fed a high-fat chow for one, two or eight weeks had increased body fat, decreased glucose tolerance, and increased fasting insulin concentrations, classic symptoms of metabolic syndrome. Daily prophylactic or therapeutic oral treatment of high-fat-fed animals with S1QEL1.719 decreased fat accumulation, strongly protected against decreased glucose tolerance and prevented or reversed the increase in fasting insulin level. Free exposures in plasma and liver at Cmax were 1-4 fold the IC50 for suppression of superoxide/hydrogen peroxide production at site IQ and substantially below levels that inhibit electron flow through complex I. These results show that the production of superoxide/hydrogen peroxide from mitochondrial site IQin vivo is necessary for the induction and maintenance of glucose intolerance caused by a high-fat diet in mice. They raise the possibility that oral administration of S1QELs may be beneficial in metabolic syndrome.

Screening of herbal plants for inhibitory activity and extracting skin-whitening active ingredients from papaya fruit

The main theme of this research was to screen for tyrosinase inhibition from extracts of seven medicinal plants with the aim of applying their skin-whitening compounds to the cosmetic industry. Specifically, the botanical parts include Morus alba L. fruit, Pachyrhizus erosus L. fruit, Glycyrrhiza uralensis F. root, Lonicera japonica T. flower, Chrysanthemum indicum L. flower, Momordica charantia L. leaf and Carica papaya L. fruit, which extracted in safe solvents as ethanol and water. The study results indicated that the tyrosinase inhibitory was higher in the ethanol-extracted products. Meanwhile, Carica papaya had high inhibitory (54.5 ± 2.97%, second only to Glycyrrhiza uralensis) and was widely grown in Viet Nam. Hence, this fruit pulp was chosen to study the suitable extracting conditions. The optimal conditions were found, with the absolute ethanol (EtOH) solvent, solid/liquid ratio of 1:8 (g/mL), 2 times extraction per patch, each time at 50 °C for 30 minutes. The expected value of extraction yield was 22.1%, tyrosinase inhibition IC50 = 768.9 μg/mL, antioxidation (DPPH method) IC50 = 1974.5 µg/mL. .

Characterization of neurotransmitter inhibition for seven cathinones by a proprietary fluorescent dye method.

Many new psychoactive substances (NPS) are stimulants, and information about their potency and abuse potential is often lacking. To start addressing this need, a method measuring the inhibition of the dopamine, serotonin, and norepinephrine transporters (DAT, SERT, and NET) by stimulant drugs was developed. The use of a proprietary fluorescent dye mixture and three cell lines (CHO-K1, HEK 293, and MDCK), each expressing a single transporter, allowed for a semiautomated, one-pot determination of inhibition in a 384-well format. The method was validated using well characterized stimulants, including cocaine, amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), α-PVP, and fluoxetine and performed similarly to other methods. Seven synthetic cathinones all showed highest potency for DAT inhibition, followed by NET and SERT. The rank potency for DAT inhibition IC50 (nM) was MPHP (4.53) > 4Cl-α-PVP (8.05) > 3F-α-PVP (12.7) > α-PiHP (13.4) > N-ethylpentylone (16.9) > N-ethylhexedrone (44.5) > 4-methylpentedrone (261). All but 4-methylpentedrone were more potent than amphetamine (257) and cocaine (111). The DAT/SERT inhibition ratio for the cathinones was in the range from 5.02 for 4-methylpentedrone to >3730 for α-PiHP, compared to 1.64 for cocaine and >4030 for α-PVP. All seven substances had inhibition profiles similar to those of potent stimulants with high abuse potential.

Identification of 2-Sulfonyl/Sulfonamide Pyrimidines as Covalent Inhibitors of WRN Using a Multiplexed High-Throughput Screening Assay.

Werner syndrome protein (WRN) is a multifunctional enzyme with helicase, ATPase, and exonuclease activities that are necessary for numerous DNA-related transactions in the human cell. Recent studies identified WRN as a synthetic lethal target in cancers characterized by genomic microsatellite instability resulting from defects in DNA mismatch repair pathways. WRN's helicase activity is essential for the viability of these high microsatellite instability (MSI-H) cancers and thus presents a therapeutic opportunity. To this end, we developed a multiplexed high-throughput screening assay that monitors exonuclease, ATPase, and helicase activities of full-length WRN. This screening campaign led to the discovery of 2-sulfonyl/sulfonamide pyrimidine derivatives as novel covalent inhibitors of WRN helicase activity. The compounds are specific for WRN versus other human RecQ family members and show competitive behavior with ATP. Examination of these novel chemical probes established the sulfonamide NH group as a key driver of compound potency. One of the leading compounds, H3B-960, showed consistent activities in a range of assays (IC50 = 22 nM, KD = 40 nM, KI = 32 nM), and the most potent compound identified, H3B-968, has inhibitory activity IC50 ∼ 10 nM. These kinetic properties trend toward other known covalent druglike molecules. Our work provides a new avenue for screening WRN for inhibitors that may be adaptable to different therapeutic modalities such as targeted protein degradation, as well as a proof of concept for the inhibition of WRN helicase activity by covalent molecules.

Discovery of an effective anti-inflammatory agent for inhibiting the activation of NF-κB

In this study, based on the effect of compounds on the activation of NF-κB and NO release, compound 51 was discovered as the best one with NO release inhibition IC50 value was 3.1 ± 1.1 μM and NF-κB activity inhibition IC50 value was 172.2 ± 11.4 nM. Compound 51 could inhibit the activation of NF-κB through suppressing phosphorylation and nuclear translocation of NF-κB, and suppress LPS-induced inflammatory response in RAW264.7 cells, such as the over-expression of TNF-α and IL-6, which were target genes of NF-κB. This compound also showed preferable anti-inflammatory activity in vivo, including alleviating significantly gastric distention and splenomegaly caused by LPS stimulation, reducing the level of oxidative stress induced by LPS, and inhibiting the expression of IL-6 and TNF-α in serum. Thus, it’s reasonable to consider that this compound is a promising small molecule with anti-inflammatory effect for inhibiting the NF-κB signalling pathway.

Synthesis and Characterization of Rutile TiO2 Nanoparticles for the Toxicological Effect on the H9c2 Cell Line from Rats.

The widespread use of titanium dioxide (TiO2) has raised concerns about potential health risks associated with its cytotoxicity in the cardiovascular system. To evaluate the cytotoxicity of TiO2 particles, the H9c2 rat cardiomyoblasts were used as a biological model, and their toxicological susceptibility to TiO2-anatase and TiO2-rutile particles was studied in vitro. The study examined dose and time exposure responses. The cell viability was evaluated based on metabolic inhibition and membrane integrity loss. The results revealed that both TiO2-anatase and TiO2-rutile particles induced similar levels of cytotoxicity at the inhibition concentrations IC25 (1.4-4.4 μg/cm2) and IC50 (7.2-9.3 μg/cm2). However, at more significant concentrations, TiO2-rutile appeared to be more cytotoxic than TiO2-anatase at 24 h. The study found that the TiO2 particles induced apoptosis events, but necrosis was not observed at any of the concentrations of particles used. The study considered the effects of microstructural properties, crystalline phase, and particle size in determining the capability of TiO2 particles to induce cytotoxicity in H9c2 cardiomyoblasts. The microstress in TiO2 particles was assessed using powder X-ray diffraction through Williamson-Hall and Warren-Averbach analysis. The analysis estimated the apparent crystallite domain and microstrain of TiO2-anatase to be 29 nm (ε = 1.03%) and TiO2-rutile to be 21 nm (ε = 0.53%), respectively. Raman spectroscopy, N2 adsorption isotherms, and dynamic light scattering were used to identify the presence of pure crystalline phases (>99.9%), comparative surface areas (10 m2/g), and ζ-potential values (-24 mV). The difference in the properties of TiO2 particles made it difficult to attribute the cytotoxicity solely to one variable.

Comparative biochemical kinase activity analysis identifies rivoceranib as a highly selective VEGFR2 inhibitor

Vascular endothelial growth factor receptor 2 (VEGFR2), a key regulator of tumor angiogenesis, is highly expressed across numerous tumor types and has been an attractive target for anti-cancer therapy. However, clinical application of available VEGFR2 inhibitors has been challenged by limited efficacy and a wide range of side effects, potentially due to inadequate selectivity for VEGFR2. Thus, development of potent VEGFR2 inhibitors with improved selectivity is needed. Rivoceranib is an orally administered tyrosine kinase inhibitor that potently and selectively targets VEGFR2. A comparative understanding of the potency and selectivity of rivoceranib and approved inhibitors of VEGFR2 is valuable to inform rationale for therapy selection in the clinic. Here, we performed biochemical analyses of the kinase activity of VEGFR2 and of a panel of 270 kinases to compare rivoceranib to 10 FDA-approved kinase inhibitors (“reference inhibitors”) with known activity against VEGFR2. Rivoceranib demonstrated potency within the range of the reference inhibitors, with a VEGFR2 kinase inhibition IC50 value of 16 nM. However, analysis of residual kinase activity of the panel of 270 kinases showed that rivoceranib displayed greater selectivity for VEGFR2 compared with the reference inhibitors. Differences in selectivity among compounds within the observed range of potency of VEGFR2 kinase inhibition are clinically relevant, as toxicities associated with available VEGFR2 inhibitors are thought to be partly due to their effects against kinases other than VEGFR2. Together, this comparative biochemical analysis highlights the potential for rivoceranib to address clinical limitations associated with off-target effects of currently available VEGFR2 inhibitors.

Antiulcer Effect of Aqueous Ethanolic Extracts of Pseudocedrela kotschyi (Schweinf) Harms (Meliaceae) and Ximenia americana L. (Olacaceae).

This study aimed to provide pharmacological evidence of Pseudocedrela kotschyi and Ximenia americana in preventing or healing peptic ulcers claimed by traditional healers in Burkina Faso. The trunk bark of Pseudocedrela kotschyi and the roots bark of Ximenia americana (Olacaceae) were macerated in mixed ethanol/water (80:20), respectively, to obtain dried extracts. Two models of hydrochloric acid (HCl, 0.3 M/ethanol, 60%) and hypothermic stress-induced peptic ulcer were used. The cytoprotective effect of individual or combined plant extracts was assessed at 1; 10; 30mg/kg. bw. Then, the healing effect of the extracts at 10mg/kg.bw was evaluated within 21 days of treatment on the hydrochloric acid-induced ulcer model. The extracts' antioxidant activity and phenolic content were assessed to support the plant extracts' efficiency. The extracts of P. kotschyi and X. americana at 10 mg/kg.bw reduced ulceration index in hydrochloric acid- and hypothermic stress-ulcer models by more than 83% and 65%, respectively. The extract from X. americana at 10mg/kg.bw allowed complete ulcer healing but not the association of the two plant extracts. The plant extracts had IC50of inhibition of DPPH radical lower than 5μg/mL and total ferric reducing antioxidant power of more than 77 mg EQAA/100mg. The total polyphenolic content was 64.82 ±0.99 and 53.75 ±1.39 mg EGA/g of dried extract of P. kotschyi and X. americana, respectively. X. americana extract is better than the combined two plant extracts in gastric cytoprotection and ulcer healing. Further investigations are needed to highlight mechanism-based effects.

Trans-cinnamaldehyde-related overproduction of benzoic acid and oxidative stress on Arabidopsis thaliana.

Trans-cinnamaldehyde is a specialised metabolite that naturally occurs in plants of the Lauraceae family. This study focused on the phytotoxic effects of this compound on the morphology and metabolism of Arabidopsis thaliana seedlings. To evaluate the phytotoxicity of trans-cinnamaldehyde, a dose-response curve was first performed for the root growth process in order to calculate the reference inhibitory concentrations IC50 and IC80 (trans-cinnamaldehyde concentrations inducing a 50% and 80% inhibition, respectively). Subsequently, the structure and ultrastructure of the roots treated with the compound were analysed by light and electron microscopy. Based on these results, the following assays were carried out to in depth study the possible mode of action of the compound: antiauxinic PCIB reversion bioassay, determination of mitochondrial membrane potential, ROS detection, lipid peroxidation content, hormone quantification, in silico studies and gene expression of ALDH enzymes. Trans-cinnamaldehyde IC50 and IC80 values were as low as 46 and 87 μM, reducing the root growth and inducing the occurrence of adventitious roots. At the ultrastructural level, the compound caused alterations to the mitochondria, which were confirmed by detection of the mitochondrial membrane potential. The morphology observed after the treatment (i.e., appearance of adventitious roots) suggested a possible hormonal mismatch at the auxin level, which was confirmed after PCIB bioassay and hormone quantification by GC-MS. The addition of the compound caused an increase in benzoic, salicylic and indoleacetic acid content, which was related to the increased gene expression of the aldehyde dehydrogenase enzymes that can drive the conversion of trans-cinnamaldehyde to cinnamic acid. Also, an increase of ROS was also observed in treated roots. The enzyme-compound interaction was shown to be stable over time by docking and molecular dynamics assays. The aldehyde dehydrogenases could drive the conversion of trans-cinnamaldehyde to cinnamic acid, increasing the levels of benzoic, salicylic and indoleacetic acids and causing the oxidative stress symptoms observed in the treated seedlings. This would result into growth and development inhibition of the trans-cinnamaldehyde-treated seedlings and ultimately in their programmed-cell-death.

Abstract 2627: The small molecule KRAS inhibitor, TEB-17231, blocks tumor progression and overcomes KRASG12C inhibitor mediated resistance

Abstract KRAS pathways are frequently upregulated in cancers bearing KRAS mutations or by other signaling modifications. Also, resistance to KRASG12C inhibitors and other KRAS/RAF/MEK pathway drugs is commonly observed in the treated cancer patients. A vital unmet need is the development of agents that potently and safely inhibit the altered KRAS signaling in these settings. A broadly acting KRAS mutation small molecule inhibitor lead series was developed using KRAS domain structure-guided scaffold modifications starting from a group of KRASG12C inhibitors. Optimized properties of these compounds were evaluated by tumor cell selectivity in vitro and pharmacophore elaboration. A novel lead series was identified with robust tumor cell growth inhibition, exemplified with the TEB-17112 lead candidate, having IC50 of inhibition against multiple KRAS-altered cell lines: NCI-H358 (KRAS-G12C, 33.6nM), AGS (KRAS-G12D, 23.5 nM), SW480 (KRAS-G12V, 22.5 nM) and A375 (KRAS-wildtype, 58.9 nM) respectively. TEB-17112 demonstrated inhibition of SW480 and H358 mouse xenografts at 25 or 50 mg/kg PO QD (21 days) without significant body weight loss. On further optimization of the lead series, TEB-17231 had on average a higher potency against KRAS mutant tumor cell lines, including H358 (12 nM), AGS (5.4 nM), SW480 (3.6 nM), and A427 (KRAS-G12D, 9.7 nM). With a candidate group of 7 compounds from this lead series, there was consistently a 5- to 6-fold selectivity of inhibition for KRAS mutant over KRAS wildtype cell lines. The lead candidate TEB-17231 was also observed to inhibit cell lines with other KRAS mutations: NCI-H1734 (KRAS-G13C, 6.5 nM), MDA-MB-231 (KRAS-G13D,11.2 nM), RPMI-8226 (KRAS-G12A, 11.3 nM), Calu-6 (KRAS-Q61K,19.8 nM), KP-2 (KRAS-G12R, 24.1 nM), LS123 (KRAS-G12S, 21 nM), as well as HRAS and NRAS mutant cell lines. TEB-17231 inhibits phospho-ERK downstream signaling in several tumor cell lines. Further, TEB-17231 exhibited tumor growth inhibition (IC50) in KRAS-G12C Ba/F3 (14 nM) and derivative cell lines that acquired resistance to G12C inhibitor MRTX849 by the additional KRAS domain mutations as follows: H95Q (32 nM), H95D (40 nM), Y96C (39 nM), Y96D (20 nM) and R68S (22 nM), compared with greater than 1μM for MRTX849. TEB-17231 induces late apoptosis of NCI-H358 cells in a manner that is time and concentration dependent. In addition to the improved selectivity and potency, TEB-17231 demonstrated satisfactory pharmacokinetics and oral bioavailability in mice (55%). Furthermore, with the SW480 (G12V) in vivo xenograft model, TEB-17231 showed clear tumor growth inhibition with QD dosing for 4-8 mg/kg PO without body weight loss. These properties highlight TEB-17231 as a potential clinically actionable inhibitor for the KRAS-modified tumor population and warrant investigation of TEB-17231 in combination with other agents in the future. Citation Format: Zusheng Xu, David T. Weaver, Robert Drakas, Yangtong Lou. The small molecule KRAS inhibitor, TEB-17231, blocks tumor progression and overcomes KRASG12C inhibitor mediated resistance [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 2627.