Antagonistic Interaction between Histone Deacetylase Inhibitor: Cambinol and Cisplatin-An Isobolographic Analysis in Breast Cancer In Vitro Models.

Breast cancer (BC) is the leading cause of death in women all over the world. Currently, combined chemotherapy with two or more agents is considered a promising anti-cancer tool to achieve better therapeutic response and to reduce therapy-related side effects. In our study, we demonstrated an antagonistic effect of cytostatic agent-cisplatin (CDDP) and histone deacetylase inhibitor: cambinol (CAM) for breast cancer cell lines with different phenotypes: estrogen receptor positive (MCF7, T47D) and triple negative (MDA-MB-231, MDA-MB-468). The type of pharmacological interaction was assessed by an isobolographic analysis. Our results showed that both agents used separately induced cell apoptosis; however, applying them in combination ameliorated antiproliferative effect for all BC cell lines indicating antagonistic interaction. Cell cycle analysis showed that CAM abolished cell cycle arrest in S phase, which was induced by CDDP. Additionally, CAM increased cell proliferation compared to CDDP used alone. Our data indicate that CAM and CDDP used in combination produce antagonistic interaction, which could inhibit anti-cancer treatment efficacy, showing importance of preclinical testing.

Pyrimidone inhibitors targeting Chikungunya Virus nsP3 macrodomain by fragment-based drug design.

The macrodomain of nsP3 (nsP3MD) is highly conserved among the alphaviruses and ADP-ribosylhydrolase activity of Chikungunya Virus (CHIKV) nsP3MD is critical for CHIKV viral replication and virulence. No small molecule drugs targeting CHIKV nsP3 have been identified to date. Here we report small fragments that bind to nsP3MD which were discovered by virtually screening a fragment library and X-ray crystallography. These identified fragments share a similar scaffold, 2-pyrimidone-4-carboxylic acid, and are specifically bound to the ADP-ribose binding site of nsP3MD. Among the fragments, 2-oxo-5,6-benzopyrimidine-4-carboxylic acid showed anti-CHIKV activity with an IC50 of 23 µM. Our fragment-based drug discovery approach provides valuable information to further develop a specific and potent nsP3 inhibitor of CHIKV viral replication based on the 2-pyrimidone-4-carboxylic acid scaffold. In silico studies suggest this pyrimidone scaffold could also bind to the macrodomains of other alphaviruses and coronaviruses and thus, have potential pan-antiviral activity.

FOXM1 drives HPV+ HNSCC sensitivity to WEE1 inhibition.

Head and neck squamous cell carcinoma (HNSCC) associated with high-risk human papilloma virus (HPV) infection is a growing clinical problem. The WEE1 kinase inhibitor AZD1775 (WEE1i) overrides cell cycle checkpoints and is being studied in HNSCC regimens. We show that the HPV16 E6/E7 oncoproteins sensitize HNSCC cells to single-agent WEE1i treatment through activation of a FOXM1-CDK1 circuit that drives mitotic gene expression and DNA damage. An isogenic cell system indicated that E6 largely accounts for these phenotypes in ways that extend beyond p53 inactivation. A targeted genomic analysis implicated FOXM1 signaling downstream of E6/E7 expression and analyses of primary tumors and The Cancer Genome Atlas (TCGA) data revealed an activated FOXM1-directed promitotic transcriptional signature in HPV+ versus HPV- HNSCCs. Finally, we demonstrate the causality of FOXM1 in driving WEE1i sensitivity. These data suggest that elevated basal FOXM1 activity predisposes HPV+ HNSCC to WEE1i-induced toxicity and provide mechanistic insights into WEE1i and HPV+ HNSCC therapies.

Mu and kappa opioid receptor agonists antagonize icilin-induced wet-dog shaking in rats.

Icilin is a cooling agent that precipitates vigorous wet-dog shakes in rats after acute i.p. administration. Recent research has emphasized the peripheral agonist properties (e.g. activation of transient receptor potential channels, TRPM8 and TRPA1) of icilin rather than its unusual and pronounced behavioral effects, often classified as quasi-morphine withdrawal. We tested selective opioid receptor agonists against icilin-induced wet-dog shakes in rats. Shaking was antagonized following s.c. pretreatment with the mu agonists, morphine (1, 2, 3 mg/kg) and buprenorphine (0.10 mg/kg) or the kappa agonists, nalfurafine (0.02, 0.04 mg/kg) and U50,488H (5 mg/kg). Pretreatment with ICI 204,448 (1, 5, 10 mg/kg), the peripherally directed kappa agonist, or the delta agonist, SNC 80 (0.30, 1, 3, 10 mg/kg), had no marked effect on the incidence of shaking. We conclude that (a) icilin can trigger shaking via interactions within the central nervous system and (b) mu and kappa opioid receptors are involved in suppressing this stimulant behavior.

Adenosine uptake inhibition ameliorates cerulein-induced acute pancreatitis in mice.

INTRODUCTION AND AIMS: Adenosine shows protective effects against cellular damage and dysfunction under several adverse conditions such as inflammation and ischemia. In the current study, we examined the effects of 3-[1-(6,7-diethoxy-2-morpholinoquinazolin-4-yl)piperidin-4-yl]-1,6-dimethyl-2,4(1,3 )-quinazolinedione hydrochloride (KF24345), an adenosine uptake inhibitor, on cerulein-induced acute pancreatitis in mice to investigate whether inhibition of adenosine uptake could ameliorate the severity of acute pancreatitis. METHODOLOGY: Acute pancreatitis was induced in mice with six intraperitoneal injections of cerulein (50 microg/kg each) at hourly intervals. RESULTS: The cerulein injection increased activities of serum amylase and lipase and caused pathologic changes such as interstitial edema, polymorphonuclear cell infiltration, and acinar cell necrosis in the pancreas. KF24345 (10 mg/kg p.o.) ameliorated all these changes observed in mice with acute pancreatitis, and the suppressing effect of KF24345 on the elevation in serum amylase activity was abolished by the treatment with 8-(p-sulfophenyl)theophylline, an adenosine receptor antagonist. In addition, 2-(aminocarbonyl)- -(4-amino-2,6-dichlorophenyl)-4-[5,5-bis-(4-fluorophenyl)pentyl]-1-piperazineacetamide (R75231) and dipyridamole, other adenosine uptake inhibitors, also decreased the elevated serum amylase activity. CONCLUSIONS: These are the first demonstrations that the adenosine uptake inhibitors ameliorate cerulein-induced acute pancreatitis in mice, and these data suggest that adenosine uptake inhibition could ameliorate the severity of acute pancreatitis in vivo.

Lysergic acid diethylamide antagonizes shaking induced in rats by five chemically different compounds.

Thyrotropin-releasing hormone (TRH), sodium valproate, AF-3-5 (1-[2-hydroxyphenyl]-4-[3-nitrophenyl]-1,2,3,6-tetrahydropyrimidine-2-one), RX336-M (7,8-dihydro-5',6'-dimethylcyclohex-5'-eno-1',2',8',14 codeinone), and Sgd 8473 (alpha-[4-chlorobenzylideneamino)-oxy]-isobutyric acid) each induced repetitive shaking of the body of rats after intraperitoneal injection. This action of the five diverse chemicals appears to be subserved by a common pharmacological component, because pretreatment with d-lysergic acid diethylamide (0.03--1.0 mg kg-1, s.c.) attenuated the shaking behavior in a dose-related manner, and cross tolerance was found between RX336-M and TRH, sodium valproate, and AG-3-5.