Dabrafenib- and trametinib-associated glomerular toxicity: A case report.

RATIONALE: Combined treatment with dabrafenib, a B-RAF inhibitor, and trametinib, a mitogen-activated protein kinase inhibitor, is an effective option for patients with metastatic melanoma. A few cases of acute kidney injury associated with tubulointerstitial nephritis and 1 case of nephrotic syndrome have been reported in patients on this drug combination; however, progressive renal injury has not been reported. In this case study, we report a patient with metastatic melanoma who developed glomerular capillary endothelial toxicity and progressive glomerular sclerosis during combination therapy. PATIENT CONCERN: Our patient was an 80-year-old woman with a history of type 2 diabetes and chronic kidney disease. DIAGNOSIS AND INTERVENTION: She was diagnosed with metastatic melanoma and commenced combination therapy with dabrafenib and trametinib. OUTCOMES: Her renal function progressively deteriorated; by month 20 after treatment commencement, her serum creatinine level had increased from 1.59 to 3.74 mg/dL. The first kidney biopsy revealed marked glomerular and endothelial cell damage. Her medication was stopped, but no improvement was evident. At 5 months after the first biopsy, her serum creatinine level had increased to 5.46 mg/dL; a second kidney biopsy revealed focal segmental glomerular sclerosis and marked tubulointerstitial fibrosis. She was started on hemodialysis. LESSONS: We describe a patient with a metastatic melanoma who developed progressive kidney failure during treatment with dabrafenib and trametinib. The most prominent microscopy findings were glomerular endothelial damage in the initial kidney biopsy and accelerated glomerular sclerosis and tubulointerstitial fibrosis in the follow-up biopsy. We hypothesize that a decreased renal reserve and impairment of kidney repair capacity caused by inhibition of B-RAF, a downstream mediator of vascular endothelial growth factor, may explain the progressive kidney injury.

MITOGEN-ACTIVATED PROTEIN INHIBITORS: FULL-FIELD ELECTRORETINOGRAM DEMONSTRATING GENERALIZED RETINAL DYSFUNCTION.

PURPOSE: To report a patient with generalized retinal toxicity to mitogen-activated protein inhibitors. METHODS: Retrospective case report. RESULTS: Full-field electroretinogram findings indicate a generalized toxicity to the use of the mitogen-activated protein inhibitor trametinib. There was an improved response and resolution of serous detachments after decreasing the dose. CONCLUSION: Mitogen-activated protein inhibitors may affect global retinal function, as opposed to the serous detachments that are concentrated in the posterior pole. This may be of importance in further understanding the underlying pathologic mechanisms.

Computational exploration of vicine - an alkaloid glycoside mediated pathological hallmark of adenosine kinase to promote neurological disorder.

Epilepsy disease is characterized by the neuronal dysfunction or abnormal neuronal activity of the brain which is regulated by astrocytes. These are glial cells and found to be the major regulators of the brain which are guided by the occurrence of adenosine kinase (ADK) enzyme in the central nervous system (CNS). During the normal physiological environment, ADK maintains the level of adenosine in the CNS. Dysfunction of ADK levels results in accumulation of adenosine levels in the CNS that leads to the pathophysiology of the brain such as astrogliosis which is a pathological hallmark of epileptic seizures. Vicine, an alkaloid glycoside in bitter gourd juice (Momordica charantia) is found to be toxic to the human system if the bitter gourd juice is consumed more. This compound inhibits ADK enzyme activity to lead epilepsy and seizure. Here, the toxic effect of vicine targeting ADK using computational predictions was investigated. The 3-dimensional structure of ADK has been constructed using I-Tasser, which has been refined by ModRefiner, GalaxyRefine, and 3D refine and it was endorsed using PROCHECK, ERRAT, and VADAR. 3D structure of the ligand molecule has been obtained from PubChem. Molecular docking has been achieved using AutoDock 4.2 software, from which the outcome showed the effective interaction between vicine and ADK, which attains binding free energy (∆G) of - 4.13 kcal/mol. Vicine molecule interacts with the active region ARG 149 of ADK and inhibits the functions of ADK that may cause imbalance in energy homeostasis. Also, pre-ADMET results robustly propose in which vicine possesses toxicity, and meanwhile, from the Ames test, it was shown as mutagenic. Hence, the results from our study suggest that vicine was shown to be toxic that suppresses the ADK activity to undergo pathological conditions in the neuronal junctions to lead epilepsy.

Transcriptome analysis to understand the effects of the toxoflavin and tropolone produced by phytopathogenic Burkholderia on Escherichia coli.

The phytopathogenic Burkholderia species B. glumae and B. plantarii are the causal agents of bacterial wilt, grain rot, and seedling blight, which threaten the rice industry globally. Toxoflavin and tropolone are produced by these phytopathogens and are considered the most hostile biohazards with a broad spectrum of target organisms. However, despite their nonspecific toxicity, the effects of toxoflavin and tropolone on bacteria remain unknown. RNA-seq based transcriptome analysis was employed to determine the genome-wide expression patterns under phytotoxin treatment. Expression of 2327 and 830 genes was differentially changed by toxoflavin and tropolone, respectively. Enriched biological pathways reflected the down-regulation of oxidative phosphorylation and ribosome function, beginning with the inhibition of membrane biosynthesis and nitrogen metabolism under oxidative stress or iron starvation. Conversely, several systems such as bacterial chemotaxis, flagellar assembly, biofilm formation, and sulfur/taurine transporters were highly expressed as countermeasures against the phytotoxins. In addition, our findings revealed that three hub genes commonly induced by both phytotoxins function as the siderophore enterobactin, an iron-chelator. Our study provides new insights into the effects of phytotoxins on bacteria for better understanding of the interactions between phytopathogens and other microorganisms. These data will also be applied as a valuable source in subsequent applications against phytotoxins, the major virulence factor.

Maltase-glucoamylase inhibition potency and cytotoxicity of pyrimidine-fused compounds: An in silico and in vitro approach.

The prevalence of diabetes mellitus has been incremented in the current century and the need for novel therapeutic compounds to treat this disease has been significantly increased. One of the most promising approaches is to inhibit intestinal alpha glucosidases. Based on our previous studies, four pyrimidine-fused heterocycles (PFH) were selected as they revealed satisfactory inhibitory action against mammalian α-glucosidase. The interaction of these compounds with both active domains of human maltase-glucoamylase (MGAM) and their effect on human Caco-2 cell line were investigated. The docking assessments suggested that binding properties of these ligands were almost similar to that of acarbose by establishing hydrogen bonds especially with Tyr1251 and Arg526 in both C-terminal and N-terminal MGAM, respectively. Also, these compounds indicated a stronger affinity for C-terminal of MGAM. L2 and L4 made tightly complexes with both terminals of MGAM which in turn revealed the importance of introducing pyrimidine scaffold and its hinge compartment. The results of molecular dynamics simulation analyses confirmed the docking data and showed deep penetration of L2 and L4 into the active site of MGAM. Based on cell cytotoxicity assessments, no significant cell death induction was observed. Hence, these functional MGAM inhibitors might be considered as new potential therapeutic compounds in treatment of diabetes and its complications.

Synthesis and evaluation of esterified Hsp70 agonists in cellular models of protein aggregation and folding.

Over-expression of the Hsp70 molecular chaperone prevents protein aggregation and ameliorates neurodegenerative disease phenotypes in model systems. We identified an Hsp70 activator, MAL1-271, that reduces α-synuclein aggregation in a Parkinson's Disease model. We now report that MAL1-271 directly increases the ATPase activity of a eukaryotic Hsp70. Next, twelve MAL1-271 derivatives were synthesized and examined in a refined α-synuclein aggregation model as well as in an assay that monitors maturation of a disease-causing Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) mutant, which is also linked to Hsp70 function. Compared to the control, MAL1-271 significantly increased the number of cells lacking α-synuclein inclusions and increased the steady-state levels of the CFTR mutant. We also found that a nitrile-containing MAL1-271 analog exhibited similar effects in both assays. None of the derivatives exhibited cellular toxicity at concentrations up to 100 µm, nor were cellular stress response pathways induced. These data serve as a gateway for the continued development of a new class of Hsp70 agonists with efficacy in these and potentially other disease models.

Evoked potential and EEG study of the neurotoxicity of hydramethylnon in rats.

The objective of the study was to assess the neurotoxicity, using electrodiagnostic tests, of hydramethylnon (Amdro, AC 217,300), an insecticide marketed for the treatment of red imported fire ants, cockroaches, and other insects. Animals were male Fisher 344 albino rats and Long-Evans hooded rats. Brainstem auditory, visual, and somatosensory evoked potentials (BAER, VEP, SEP) and electroencephalograms (EEG) were recorded from implanted screw electrodes before and at multiple time points through day 10 after a single oral dose of hydramethylnon (at 50% or 75% of the LD50) plus vehicle, or vehicle alone. No evidence of nervous system toxicity was detected with either BAER, VEP, or SEP recordings. Spectral analysis of EEGs recorded over 7days demonstrated a time-limited increase in power at low frequencies and decrease at high frequencies, reflecting a sedative effect. A dose-dependent weight loss was observed. Single-exposure poisonings with AC 217,300 can be expected to produce anorexia and CNS depression, but not lethality.

Acetaminophen cytotoxicity in HepG2 cells is associated with a decoupling of glycolysis from the TCA cycle, loss of NADPH production, and suppression of anabolism.

Acetaminophen (APAP) is one of the most commonly used analgesics worldwide, and overdoses are associated with lactic acidosis, hepatocyte toxicity, and acute liver failure due to oxidative stress and mitochondrial dysfunction. Hepatoma cell lines typically lack the CYP450 activity to generate the reactive metabolite of APAP observed in vivo, but are still subject to APAP cytotoxicity. In this study, we employed metabolic profiling and isotope labelling approaches to investigate the metabolic impact of acute exposure to cytotoxic doses of APAP on the widely used HepG2 cell model. We found that APAP exposure leads to limited cellular death and substantial growth inhibition. Metabolically, we observed an up-regulation of glycolysis and lactate production with a concomitant reduction in carbon from glucose entering the pentose-phosphate pathway and the TCA cycle. This was accompanied by a depletion of cellular NADPH and a reduction in the de novo synthesis of fatty acids and the amino acids serine and glycine. These events were not associated with lower reduced glutathione levels and no glutathione conjugates were seen in cell extracts. Co-treatment with a specific inhibitor of the lactate/H+ transporter MCT1, AZD3965, led to increased apoptosis in APAP-treated cells, suggesting that lactate accumulation could be a cause of cell death in this model. In conclusion, we show that APAP toxicity in HepG2 cells is largely independent of oxidative stress, and is linked instead to a decoupling of glycolysis from the TCA cycle, lactic acidosis, reduced NADPH production, and subsequent suppression of the anabolic pathways required for rapid growth.

Chemical Synthesis Enables Structural Reengineering of Aglaroxin C Leading to Inhibition Bias for Hepatitis C Viral Infection.

As a unique rocaglate (flavagline) natural product, aglaroxin C displays intriguing biological activity by inhibiting hepatitis C viral entry. To further elucidate structure-activity relationships and diversify the pyrimidinone scaffold, we report a concise synthesis of aglaroxin C utilizing a highly regioselective pyrimidinone condensation. We have prepared more than 40 aglaroxin C analogues utilizing various amidine condensation partners. Through biological evaluation of analogues, we have discovered two lead compounds, CMLD012043 and CMLD012044, which show preferential bias for the inhibition of hepatitis C viral entry vs translation inhibition. Overall, the study demonstrates the power of chemical synthesis to produce natural product variants with both target inhibition bias and improved therapeutic indexes.

Synthesis and In Vitro Anticancer Activity of 6-Ferrocenylpyrimidin-4(3H)-one Derivatives.

AIM AND OBJECTIVE: Some ferrocenyl derivatives are active in vitro and in vivo against cancer. Generally, ferrocenyl derivatives for cancer research have three key components: a ferrocene moiety, a conjugated linker that lowers the oxidation potential and some derivative (peptide, nucleobase and others) that can interact with biomolecules. Since the pyrimidine fragment can easily pass through the membrane into the cells and become involved in metabolism; it appears to be promising. Furthermore, this fragment is an electron-acceptor group, so a spacer can be excluded. Therefore, the synthesis of 6-ferrocenylpyrimidin-4(3H)-one derivatives and the study of their anticancer activity have scientific and practical interest. METHODS: The syntheses of 6-ferrocenylpyrimidin-4(3H)-one derivatives were performed by the condensation of ethyl 3-ferrocenyl-3-oxopropionate with thiourea or acetamidine or guanidine. The cytotoxicity of four 6- ferrocenylpyrimidin-4(3H)-one derivatives was evaluated by using the MTT assay in vitro against Human breast adenocarcinoma MCF-7 and normal human skin fibroblast HSF cells. The tested derivatives induced a concentration-dependent cytotoxic response in cell lines. RESULTS: A study of the cytotoxic activity of 6-ferrocenylpyrimidin-4(3H)-one derivatives by the MTT test has found that all compounds have a dose-dependent toxic effect on the lines of breast cancer cells (MCF-7) and normal human fibroblast cells (HSF). The most pronounced cytotoxic effect is exhibited by 2-methyl-6-ferrocenylpyrimidin- 4(3H)-one (MCF-7, IC50 17 ± 1 µM). CONCLUSION: The experimental results confirm the importance of investigation and design of ferrocenylpyrimidin- 4(3H)-one derivatives as anticancer agents. Compounds where the pyrimidine derivatives are directly linked to the ferrocene unit rather than via a spacer group also may be of interest for antiproliferative drug design.

Superior cellular activities of azido- over amino-functionalized ligands for engineered preQ1 riboswitches in E.coli.

For this study, we utilized class-I and class-II preQ1-sensing riboswitches as model systems to decipher the structure-activity relationship of rationally designed ligand derivatives in vitro and in vivo. We found that synthetic preQ1 ligands with amino-modified side chains that protrude from the ligand-encapsulating binding pocket, and thereby potentially interact with the phosphate backbone in their protonated form, retain or even increase binding affinity for the riboswitches in vitro. They, however, led to significantly lower riboswitch activities in a reporter system in vivo in E. coli. Importantly, when we substituted the amino- by azido-modified side chains, the cellular activities of the ligands were restored for the class-I conditional gene expression system and even improved for the class-II counterpart. Kinetic analysis of ligand binding in vitro revealed enhanced on-rates for amino-modified derivatives while they were attenuated for azido-modified variants. This shows that neither high affinities nor fast on-rates are necessarily translated into efficient cellular activities. Taken together, our comprehensive study interconnects in vitro kinetics and in vitro thermodynamics of RNA-ligand binding with the ligands' in vivo performance and thereby encourages azido- rather than amino-functionalized design for enhanced cellular activity.

Synthesis and biological screening of new thiazolo[4,5-d]pyrimidine and dithiazolo[3,2-a:5',4'-e]pyrimidinone derivatives as antimicrobial, antiquorum-sensing and antitumor agents.

New thiazolopyrimidine and dithiazolopyrimidinone derivatives 2-11 were synthesized and estimated for antimicrobial activity against S. aureus, B. cereus, E. coli, C. albicans, A. fumigatus and A. terreus. The attained results proved that 4, 8a and 11g have significant effectiveness against S. aureus and B. cereus. On the other hand, 7, 10b, 10c and 11h exhibited prominent activity against B. cereus, whereas 8a, 10b and 11g were proved to be active against E. coli. From another point of view, 4 and 8a exhibited promising efficacy against A. fumigatus and A. terreus; moreover, 8a showed outstanding efficacy against C. albicans. Quorum-sensing inhibitory activity of the new compounds was esteemed against C. violaceum, where 7, 8a, 9b, 10a-c, 11d and 11g have acceptable efficacy. In vitro antitumor efficacy of the same compounds against HepG2, HCT-116 and MCF-7 cancer cell lines was also tested. Compounds 4 and 11h showed enhanced effectiveness against the three cell lines, whereas 10b displayed eminent activity against HCT-116 and MCF-7 cells. Moreover, 11a was found to have outstanding activity against MCF-7 cells, while 11i showed promising efficacy against HepG2 cells. The in vitro active antitumor compounds were evaluated for in vivo antitumor effectiveness against EAC in mice, as well as in vitro cytotoxicity against WI38 and WISH normal cells. Results manifested that 4 has the strongest in vivo activity, and that all investigated analogs are less cytotoxic than 5-FU against both normal cell lines. DNA-binding affinity of the active compounds was examined, where 4, 8a, 10c, 11d and 11g,h displayed strong affinity. In silico studies proved that majority of the analyzed compounds are in conformity with the optimum needs for good oral absorption.

Discovery of TRPM8 Antagonist ( S)-6-(((3-Fluoro-4-(trifluoromethoxy)phenyl)(3-fluoropyridin-2-yl)methyl)carbamoyl)nicotinic Acid (AMG 333), a Clinical Candidate for the Treatment of Migraine.

Transient-receptor-potential melastatin 8 (TRPM8), the predominant mammalian cold-temperature thermosensor, is a nonselective cation channel expressed in a subpopulation of sensory neurons in the peripheral nervous system, including nerve circuitry implicated in migraine pathogenesis: the trigeminal and pterygopalatine ganglia. Genomewide association studies have identified an association between TRPM8 and reduced risk of migraine. This disclosure focuses on medicinal-chemistry efforts to improve the druglike properties of initial leads, particularly removal of CYP3A4-induction liability and improvement of pharmacokinetic properties. A novel series of biarylmethanamide TRPM8 antagonists was developed, and a subset of leads were evaluated in preclinical toxicology studies to identify a clinical candidate with an acceptable preclinical safety profile leading to clinical candidate AMG 333, a potent and highly selective antagonist of TRPM8 that was evaluated in human clinical trials.

Development of Potent Pyrazolopyrimidinone-Based WEE1 Inhibitors with Limited Single-Agent Cytotoxicity for Cancer Therapy.

WEE1 kinase regulates the G2 /M cell-cycle checkpoint, a critical mechanism for DNA repair in cancer cells that can confer resistance to DNA-damaging agents. We previously reported a series of pyrazolopyrimidinones based on AZD1775, a known WEE1 inhibitor, as an initial investigation into the structural requirements for WEE1 inhibition. Our lead inhibitor demonstrated WEE1 inhibition in the same nanomolar range as AZD1775, and potentiated the effects of cisplatin in medulloblastoma cells, but had reduced single-agent cytotoxicity. These results prompted the development of a more comprehensive series of WEE1 inhibitors. Herein we report a series of pyrazolopyrimidinones and identify a more potent WEE1 inhibitor than AZD1775 and additional compounds that demonstrate that WEE1 inhibition can be achieved with reduced single-agent cytotoxicity. These studies support that WEE1 inhibition can be uncoupled from the potent cytotoxic effects observed with AZD1775, and this may have important ramifications in the clinical setting where WEE1 inhibitors are used as chemosensitizers for DNA-targeted chemotherapy.

A practical toxicity bioassay for vicine and convicine levels in faba bean (Vicia faba).

BACKGROUND: Faba bean (Vicia faba) vicine and convicine (V-C) aglycones (divicine and isouramil respectively) provoke an acute hemolytic anemia called favism in individuals with a glucose-6-phosphate dehydrogenase (G6PD) enzyme defect in their red blood cells. Geneticists/plant breeders are working with faba bean to decrease V-C levels to improve public acceptance of this high-protein pulse crop. Here, we present a fast and simple ex vivo in vitro bioassay for V-C toxicity testing of faba bean or faba bean food products. RESULTS: We have shown that 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU)-treated (i.e., sensitized) normal red blood cells, like G6PD-defective blood, displayed (i) continuous glutathione (GSH) depletion with no regeneration as incubation time and the dose of aglycones increased, (ii) progressive accumulation of denatured hemoglobin products into high molecular weight (HMW) proteins with increased aglycone dose, (iii) both band 3 membrane proteins and hemichromes, in HMW protein aggregates. We have also demonstrated that sensitized red blood cells can effectively differentiate various levels of toxicity among faba bean varieties through the two hemolysis biomarkers: GSH depletion and HMW clumping. CONCLUSION: BCNU-sensitized red blood cells provide an ideal model for favism blood, to assess and compare the toxicity of faba bean varieties and their food products. © 2018 Society of Chemical Industry.

Selective toxicity of the mesoionic insecticide, triflumezopyrim, to rice planthoppers and beneficial arthropods.

The novel mesoionic insecticide triflumezopyrim was highly effective in controlling both imidacloprid-susceptible and resistant planthopper populations in Malaysia. However, the toxicity of triflumezopyrim to planthopper populations and their natural enemies has been under-investigated in China. In this study, the median lethal concentrations (LC50) of triflumezopyrim were determined in eight field populations of Nilaparvata lugens and one population of Sogatella furcifera from China under laboratory conditions. Triflumezopyrim showed higher toxicity to planthopper populations than the commonly-used insecticide, imidacloprid. Furthermore, the lethal effect of triflumezopyrim on eight beneficial arthropods of planthoppers was investigated in the laboratory and compared with three commonly-used insecticides, thiamethoxam, chlorpyrifos and abamectin. Triflumezopyrim was harmless to Anagrus nilaparvatae, Cyrtorhinus lividipennis and Paederus fuscipes, while thiamethoxam, chlorpyrifos and abamectin were moderately harmful or harmful to the insect parasitoid and predators. Triflumezopyrim and thiamethoxam were harmless to the predatory spiders Pirata subpiraticus, Ummeliata insecticeps, Hylyphantes graminicola and Pardosa pseudoannulata, and slightly harmful to Theridion octomaculatum. Chlorpyrifos caused slight to high toxicity to four spider species except U. insecticeps. Abamectin was moderately to highly toxic to all five spider species. Our results indicate that triflumezopyrim has high efficacy for rice planthoppers populations and is compatibile with their natural enemies in China.

Identification of N-arylsulfonylpyrimidones as anticancer agents.

For confirming the role of five membered ring of imidazolidinone moiety of N-arylsulfonylimidazolidinones (7) previously reported with highly potent anticancer agent, a series of N-arylsulfonylpyrimidones (10a-g) and N-arylsulfonyltetrahydropyrimidones (11a-e) were prepared and their anti-proliferating activity was measured against human cancer cell lines (renal ACHN, colon HCT-15, breast MDA-MB-231, lung NCI-H23, stomach NUGC-3, and prostate PC-3) using XTT assay. Among them, 1-(1-acetylindolin-5-ylsulfonyl)-4-phenyltetrahydropyrimidin-2(1H)-one (11d, mean GI50 = 3.50 µM) and ethyl 5-(2-oxo-4-phenyltetrahydropyrimidin-1(2H)-ylsulfonyl)-indoline-1-carboxylate (11e, mean GI50 = 0.26 µM) showed best growth inhibitory activity against human cancer cell lines. Considering the activity results, N-arylsulfonyltetrahydropyrimidones (11) exhibited more potent activity compared to N-arylsulfonylpyrimidones (10) and comparable activity to N-arylsulfonylimidazolidinones (7). Especially, tetrahydropyrimidin-2(1H)-one analogs containing acylindolin-5-ylsulfonyl moiety at position 1 demonstrated their strong growth inhibitory activity against human cancer cell lines.

Xanthine Oxidase Inhibitory and Molecular Docking Studies on Pyrimidones.

BACKGROUND: Xanthine oxidase is an important enzyme which catalyzes the production of uric acid and superoxide anion from xanthine. The over-production of these products leads to different disease conditions. For instance, uric acid is responsible for hyperuricemia, gout, and arthritis, while superoxide anion contributes to the oxidative stress, and related diseases. Hence XO is an important pharmacological target for the treatment of a range of diseases. METHODS: Based on the structural resemblance of pyrimidines with xanthine, a series of previously synthesized ethyl 6- methyl-2-oxo-1, 2, 3, 4-tetrahydro-5-pyrimidinecarboxylate derivatives were evaluated for XO inhibitory activity. RESULTS: Among 25 pyrimidone derivatives, 22 were found to be good to weak inhibitors with IC50 values in the range of 14.4 - 418 µM. Compounds 3, 14, 15, 18, and 21-23 were significant inhibitors, and thus analyzed for their kinetic parameters. Among them compounds 14, 15, 18, and 23 were competitive, 21 and 22 showed non-competitive, while 23 was a mixed-type of inhibitor. Molecular docking studies highlighted the interactions of these inhibitors with critical amino acids of XO, such as Val1011, Phe649, Lys771, and others. Moreover, the cytotoxicity studies on these selected inhibitors showed all these compounds to be non-cytotoxic. CONCLUSION: These non-cytotoxic, significant XO inhibitors can thus be further investigated for the treatment of hyperuricemia, and gout.

ß-Catenin Cooperates with CREB Binding Protein to Promote the Growth of Tumor Cells.

BACKGROUND/AIMS: ß-catenin is an integral component of the canonical Wnt signaling pathway, and its mutations are an autosomal recessive cause of colorectal cancer (CRC), medulloblastoma (MDB), and ovarian cancer. Nevertheless, little is known about its function in lung cancers. METHODS: We first knocked down ß-catenin by siRNA to investigate its effects on lung cancer cell proliferation, migration and apoptosis. Then we verified the interaction between ß-catenin and CREB binding protein (CBP) by immunofluoresence and co-immunoprecipition assays. Finally, the expression of ß-catenin and CBP in human lung adenocarcinoma specimens were analyzed by immunohistochemistry assay. RESULTS: ß-catenin knockdown inhibited cell proliferation, promoted apoptosis and suppressed cell migration in A549 and H460 cells accompanied by the decreased expression of Myc, PCNA, VEGF, CD44, MMP-9, MMP-13 and activated bax/caspase-3 pathway. Furthermore, co-immunoprecipition and immunofluoresence analyses revealed that CBP interacted with ß-catenin and contributed to ß-catenin-mediated lung cancer cell growth. Abolishment of their interaction by the Wnt/ß-catenin inhibitor ICG-001 remarkably suppressed cell proliferation. Immunohistochemistry assay of tissue microarrays from patients with lung cancer indicated that both CBP and ß-catenin were highly expressed in tumor tissues and predicted poor prognosis in lung adenocarcinoma patients. CONCLUSIONS: Our study has provided new evidence for the role of ß-catenin in promoting the growth of lung cancer cells through cooperation with CBP, and suggested that dual targeting of ß-catenin and CBP could be a potential therapeutic strategy in lung cancer treatment.

IQGAP1 is an oncogenic target in canine melanoma.

Canine oral mucosal melanoma is an aggressive malignant neoplasm and is characterized by local infiltration and a high metastatic potential. The disease progression is similar to that of human oral melanomas. Whereas human cutaneous melanoma is primarily driven by activating mutations in Braf (60%) or Nras (20%), human mucosal melanoma harbors these mutations much less frequently. This makes therapeutic targeting and research modeling of the oral form potentially different from that of the cutaneous form in humans. Similarly, research has found only rare Nras mutations and no activating Braf mutations in canine oral melanomas, but they are still reliant on MAPK signaling. IQGAP1 is a signaling scaffold that regulates oncogenic ERK1/2 MAPK signaling in human Ras- and Raf- driven cancers, including melanomas. To investigate whether IQGAP1 is a potential target in canine melanoma, we examined the expression and localization of IQGAP1 in primary canine melanomas and canine oral melanoma cell lines obtained from the University of California-Davis. Using CRISPR/Cas9 knockout of IQGAP1, we examined effects on downstream ERK1/2 pathway activity and assayed proliferation of cell lines when treated with a peptide that blocks the interaction between IQGAP1 and ERK1/2. We observed that canine IQGAP1 is expressed and localizes to a similar extent in both human and canine melanoma by qPCR, Western blot, and immunofluorescence. Deletion of IQGAP1 reduces MAPK pathway activation in cell lines, similar to effects seen in human BrafV600E cell lines. Additionally, we demonstrated reduced proliferation when these cells are treated with a blocking peptide in vitro.