Application of Pharmacokinetic/Pharmacodynamic Modeling to Bridge Mouse Antitumor Efficacy and Monkey Toxicology Data for Determining the Therapeutic Index of an Interleukin-10 Fc Fusion Protein

Pharmacokinetic/pharmacodynamic (PK/PD) modeling was performed to quantitatively integrate preclinical pharmacology and toxicology data for determining the therapeutic index (TI) of an interleukin-10 (IL-10) fragment crystallizable (Fc) fusion protein. Mouse Fc fused with mouse IL-10 (mFc-mIL-10) was studied in mice for antitumor efficacy, and the elevation of interleukin-18 (IL-18) was examined as a PD biomarker. The in vivo mFc-mIL-10 EC₅₀ for the IL-18 induction was estimated to be 2.4 nM, similar to the in vitro receptor binding affinity (K_d) of 3.2 nM. The IL-18 induction was further evaluated in cynomolgus monkeys, where the in vivo induction EC₅₀ by a human IL-10 human Fc-fusion protein (hFc-hIL-10) was 0.08 nM vs. 0.3 nM measured as the in vitro K_d. The extent of the IL-18 induction correlated with mouse antitumor efficacy and was used to connect mouse efficacy to that in monkeys. The PD-based efficacious dose projected in monkeys was comparable to the results obtained using a PK-based method in which mouse efficacious exposure was targeted and corrected for affinity differences between the species. Furthermore, PK/PD relationships were developed for anemia and thrombocytopenia in monkeys treated with hFc-hIL-10, with thrombocytopenia predicted to be dose-limiting toxicity. Using quantitative pharmacology and toxicology information obtained through modeling work in the same species, the TI of hFc-hIL-10 in monkeys was determined to be 2.4 (vs. PD-based efficacy) and 1.2–3 (vs. PK-based efficacy), indicating a narrow safety margin. The model-based approaches were proven valuable to the developability assessment of the IL-10 Fc-fusion protein.

Demographic history of the fragmented yellowthroated bulbul (Pycnonotus xantholaemus) population in the Deccan Peninsula, India

The yellow-throated bulbul (YTB) is an endemic passerine restricted to scrub forests along hill slopes with exposed rocky outcrops in the Deccan Peninsula, India. It is found in small, discontinuous populations and is vulnerable to extinction due to ongoing habitat loss and subsequent population decline. To assess the genetic connectivity and past demography, we sequenced 1050 nucleotide base pairs of the mitochondrial control region of 60 individuals that represent distinct populations in the geographic range of the species. We recovered 39 haplotypes defined by 81 variable sites. Haplotype diversity was high with low nucleotide diversity, suggesting rapid population growth from a founder population with a small effective population size. The negative values of Tajima’sDand Fu’sFsand small positive value of Ramos-Onsins and Rozas’R2suggest deviation from neutrality and population expansion. The haplotype network and demographic expansion parameters further suggest historical population expansion. Mismatch analysis statistics and Bayesian skyline plots estimate population expansion during the late Pleistocene. Although the species presently occurs in small, disconnected we found no structuring of the population. Dispersal events are the most likely explanation for the absence of genetic structuring in the YTB population. These results represent important data for the design of a conservation plan for this endemic and globally threatened species.

First report of Burkholderia pseudomallei ST412 and ST734 clones harbouring blaOXA-57 but susceptible to imipenem in India

Melioidosis caused by Burkholderia pseudomallei has become an important clinical threat, especially in Northern Australia and Southeast Asia. However, the genome information on this pathogen is limited. B. pseudomallei isolates identified from bloodstream infections from inpatients were subjected to whole-genome sequencing by IonTorrent PGM and MinION Oxford Nanopore sequencing technologies. Highly accurate complete genomes of two strains, VB3253 and VB2514, were obtained by a hybrid genome assembly method using both short and long DNA reads. Both isolates carried blaPenI and carbapenemase-encoding blaOXA-57 genes, although the isolates were susceptible to imipenem by E-test method with MIC 1 μg/mL. Multiple IS family transposases specific for all non-fermenting Gram-negative bacteria (NFGNBs)—especially IS3 and IS5, which facilitate mobilization of extended-spectrum β-lactamase (ESBL) and carbapenemase genes—were carried in these genomes. This further adds to the complexity of gene transmission. These IS families were identified only upon hybrid genome assembly and would otherwise be missed.

Uptake of HIV testing and HIV positivity among presumptive tuberculosis patients at Puducherry, South India

SETTING

Puducherry, a district in South India with a low prevalence of human immunodeficiency virus (HIV) infection (<1% among antenatal women).

OBJECTIVES

1) To estimate the proportion of patients with known HIV status who were HIV-positive, 2) to describe the demographic and clinical characteristics of patients with unknown HIV status among presumptive TB patients, and 3) to assess the additional workload at HIV testing centres.

DESIGN

In this cross-sectional study, consecutive presumptive TB patients attending microscopy centres for diagnosis during March-May 2013 were asked if they knew their HIV status. Patients with unknown HIV status were offered voluntary counselling and HIV testing.

RESULTS

Of 1886 presumptive TB patients, HIV status was ascertained for 842 (44.6%); 28 (3.3%) were HIV-positive. The uptake of HIV testing was significantly higher in younger age groups, males, residents of Puducherry and smear-positive TB patients. The median increase in the number of clients tested for HIV per day per testing centre was 1 (range 0-6).

CONCLUSION

The uptake of HIV testing was low. HIV prevalence was higher among presumptive TB patients than in antenatal women, and as high as in TB patients. With minimal increase in workload at HIV testing centres, HIV testing could be implemented using existing resources.

Antibiotic treatment of pregnant non-obese diabetic mice leads to altered gut microbiota and intestinal immunological changes in the offspring

The intestinal microbiota is important for tolerance induction through mucosal immunological responses. The composition of the gut microbiota of an infant is affected by environmental factors such as diet, disease and antibiotic treatment. However, already in utero, these environmental factors can affect the immunological development of the foetus and influence the future gut microbiota of the infant. To investigate the effects of antibiotic treatment of pregnant mothers on the offspring's gut microbiome and diabetes development, we treated non-obese diabetic (NOD) mice with a cocktail of antibiotics during gestation and the composition of the gut microbiota, diabetes incidence and major gut-related T lymphocyte populations were investigated in the offspring. We observed a persistent reduction in the general diversity of the gut microbiota in the offspring from NOD mothers treated with antibiotics during gestation compared with offspring from control mothers. In addition, by clustering the present bacterial taxa with principal component analysis, we found a differential clustering of gut microbiota in the offspring from NOD mothers treated with antibiotics during gestation compared with offspring from control mothers. Offspring from NOD mothers treated with antibiotics during gestation also showed some immunological alterations in the gut immune system, which could be related to the diversity of the gut microbiome and influence modulation of diabetes development at 20 weeks. Our data point out maternal derangement of the intestinal microbiota as a potential environmental risk factor for T1D development.

Abstract C221: A genome-wide RNA interference screen identifies synthetic lethal interactions with the BRAF oncogene

Oncogenic mutations in BRAF are found in 50-70% of malignant melanomas and in ∼8% of all cancers. Activating BRAF mutations confer exquisite dependency on RAF/MEK/ERK signaling and RAF and MEK inhibitors achieved striking clinical response in the majority of patients with BRAFV600E-mutant melanoma. However, nearly all patients progress to therapeutic resistance and there are limited treatment options for patients with relapsed tumors. Identification of genes that are essential only in the presence of BRAFV600E mutation may inform alternative as well as combinatorial therapeutic approaches. Here, we used systematic RNA interference to discover synthetic lethal interactions in melanoma cells carrying BRAFV600E mutation. In addition, Project Achilles at the Broad Institute reported systematic loss-of-function studies in more than 100 human cancer cell lines. We intersected the list of genes that are synthetic lethal with BRAFV600E mutation in our melanoma study and that of Project Achilles. As a result, we have identified novel “druggable” targets for cells driven by BRAFV600E mutation. Our extensive in vitro and in vivo validation has confirmed and established key synthetic lethal interactions with BRAFV600E mutation. One major mechanism of acquired resistance to RAF and MEK inhibition is reactivation of MEK/ERK pathway. Importantly, we demonstrated that these synthetic lethal genes are also essential in the context of acquired resistance to RAF and MEK inhibition. Together, our study has identified novel targets for the treatment of oncogenic BRAF-driven melanoma and suggests targeting these genes as novel therapeutic strategies to overcome acquired resistance to RAF and MEK inhibition.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C221.

Citation Format: Chengyin Min, David J. Konieczkowski, Christine Kwon, Marika Linja, Krishna Vasudevan, Barbara Weir, Eva Goetz, Levi Garraway. A genome-wide RNA interference screen identifies synthetic lethal interactions with the BRAF oncogene. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr C221.

Anti-cell proliferative efficacy of ferulic acid against 7, 12-dimethylbenz(a) anthracene induced hamster buccal pouch carcinogenesis

The present study was designed to explore the anti-cell proliferative efficacy of ferulic acid by analysing the expression pattern of cell proliferative markers, proliferating cellular nuclear antigen (PCNA) and cyclin D1, in the buccal mucosa of golden Syrian hamsters treated with 7,12-dimethylbenz(a)anthracene (DMBA). Oral squamous cell carcinomas developed in the buccal pouch of hamsters using topical application of 0.5% DMBA three times a week for 14 weeks. Immunohistochemical (PCNA) and RT-PCR (Cyclin D1) analysis revealed over expression of PCNA and cyclin D1 in the buccal mucosa of hamsters treated with DMBA alone (tumor bearing hamsters). Oral administration of ferulic acid at a dose of 40 mg/kg bw to hamsters treated with DMBA not only completely prevented the tumor formation but also down regulated the expression of PCNA and cyclin D1. The results of the present study thus suggests that ferulic acid might have inhibited tumor formation in the buccal mucosa of hamsters treated with DMBA through its anti-cell proliferative potential as evidenced by decreased expression of PCNA and cyclin D1.

Abstract 3133: Identification and functional validation of novel genetically-linked breast cancer targets through pooled gain-of-function screening

Breast cancer is one of the most common cancer types, with greater than 450,000 deaths reported per year worldwide. Through genome wide sequencing efforts, multiple genetic alterations have been identified, including mutations and amplifications in genes such as v-erb-b2 erythroblastic leukemia viral oncogene homolog 2 (ERBB2), GATA binding protein 3 (GATA3), phosphatidylinositol 3-kinase alpha catalytic subunit (PIK3CA) as well as novel genomic rearrangements such as the recently identified MAGI3-AKT3 fusion. Now that breast cancer can be characterized to an unprecedented level, one of the key challenges remaining is to identify and distinguish critical ‘driver’ events responsible for tumor progression, from neutral ‘passenger’ lesions. In order to achieve this, we utilized high resolution aCGH analysis of 50 purified breast cancer samples (made up of Her2+, estrogen receptor positive (ER+) and triple negative tumors with variable responses to SOC regimens), in combination with a Gain-of-Function transformation screen to identify and validate novel breast targets. 158 genomic regions were found to be recurrently amplified, consisting of 759 genes in total. The top 32 focally amplified genes, along with 12 cancer-relevant mutant alleles were prioritized and a library generated utilizing the pTRIPZ-tetracycline regulated inducible lentiviral vector system. These 44 genes were subsequently combined into 16 different target pools (5-13 targets per pool, co-expressing genes that were co-amplified in the same clinical specimen) and evaluated for their ability to transform immortalized breast epithelial MCF10A cells (both wild-type and p53 -/- cells). Through this screening approach, p21-activated kinase 1 (PAK1) was identified, whose kinase activity was required to robustly transform MCF10A cells through regulating multiple signalling pathways including MAPK. Several other putative oncogenes were also identified and will be presented here, including the glycosyltransferse asparagine-linked glycosylation 8 (ALG8). Interestingly, PAK1 and ALG8 are co-amplified in both breast (8%) and ovarian cancers (11%). Our target validation studies have suggested that ALG8 can support PAK1-induced transformation, as dramatic suppression of soft-agar colony growth was seen in co-amplified breast cancer cell lines upon combined siRNA treatment to both targets. Thus, this combined high resolution aCGH profiling and functional screening approach has enabled the successful identification of novel oncogenic targets in breast cancer.

Citation Format: Krishna Vasudevan, Axel Hernandez, Zhongwu Lai, Yonghong Xiao, Nin Guan, Carolyn Hardy, Robert Godin, Christopher Denz, Minwei Ye, Elizabeth Lenkiewicz, Stephanie Savage, Michael T. Barrett, Donna Prunkard, Peter Rabinovitch, Mark Basik, Ewa Przybytkowski, Kevin Webster, Michael Zinda, Emma-Louise Jenkins. Identification and functional validation of novel genetically-linked breast cancer targets through pooled gain-of-function screening. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3133. doi:10.1158/1538-7445.AM2013-3133

In vitro fertility rate of 129 strain is improved by buserelin (gonadotropin-releasing hormone) administration prior to superovulation

The 129 mice are well recognized for their low fertility and it is speculated that this lack of fertility may be due to the oocyte condition. In this study we investigated superovulation regimens for the 129S1/SvImJ mouse strain to improve the oocyte quality and fertility rate of in vitro fertilization (IVF). Female mice were divided into four groups based on hormone and timing of injection. Group 1 received pregnant mare serum gonadotropin (PMSG) and 48 h later human chorionic gonadotropin (hCG); using the same dose, group 2 received hCG 52 h post-PMSG and group 3, 55 h post-PMSG. Group 4 received buserelin (gonadotropin-releasing hormone agonist [GnRH]) followed 24 h later by PMSG and then hCG 55 h post-PMSG. IVF was performed using 129S1/SvImJ oocytes and sperm; C57BL/6J sperm with 129S1/SvImJ oocytes was used as fertility control. The IVF fertility rate was 1% (Groups 1 and 2), 17% (Group 3) and 55% (Group 4) for 129 oocytes fertilized with 129 sperm. For 129 oocytes fertilized with C57BL/6J sperm, the fertility rate was 5% (Group 1), 10% (Group 2), 40% (Group 3) and 59% (Group 4). These results suggest that extending the interval time between PMSG and hCG and giving GnRH in addition to the standard PMSG and hCG treatments can improve IVF fertility rate of 129S1/SvImJ mouse strains significantly.

Adenomatoid odontogenic tumor, an uncommon tumor

Here we report a case of adenomatoid odontogenic tumor (AOT) in the maxilla in a young girl aged 14 years and its surgical management. We also review the literature and variations in the nomenclature and classifications of this interesting tumor. The review of literature gives an interesting picture regarding terminologies in the past and dilemma in classifying this tumor. The introduction of the name adenomatoid odontogenic tumour has resulted in the simpler and fruitful surgical management like enucleation and curettage with no reports of recurrences. In the past, similar lesion with the terminology like adeno ameloblastoma has resulted in unnecessary mutilating surgery. The conflicting views whether the lesion is being neoplasm or an anomalous hamartomatous growth is also being discussed.

Quantum chemistry calculations of 3-Phenoxyphthalonitrile dye sensitizer for solar cells

The geometries, electronic structures, polarizabilities, and hyperpolarizabilities of organic dye sensitizer 3-Phenoxyphthalonitrile were studied based on Hartree-Fock (HF) and density functional theory (DFT) using the hybrid functional B3LYP. Ultraviolet-visible (UV-vis) spectrum was investigated by time dependent DFT (TD-DFT). Features of the electronic absorption spectrum in the visible and near-UV regions were assigned based on TD-DFT calculations. The absorption bands are assigned to pi-->pi* transitions. Calculated results suggest that the three excited states with the lowest excited energies in 3-Phenoxyphthalonitrile is due to photoinduced electron transfer processes. The interfacial electron transfer between semiconductor TiO(2) electrode and dye sensitizer 3-Phenoxyphthalonitrile is due to an electron injection process from excited dye to the semiconductor's conduction band. The role of phenoxy group in 3-Phenoxyphthalonitrile in geometries, electronic structures, and spectral properties were analyzed.

Antiatherogenic effect of taurine in high fat diet fed rats

The role of taurine on atherogenesis induced by high fat diet in rats, a species which depends entirely on taurine for conjugation of bile acids has been investigated. Wistar male rats were fed on (p.o.) taurine in addition to high fat diet (11% coconut oil w/w) for 6 months. High fat diet caused significant increase of serum total cholesterol (2 fold), serum triglycerides (92.6%), LDL cholesterol (92.3%) and body weight gain (2.8 fold). Taurine administration significantly reduced serum cholesterol (37%), triglycerides (94.5%), LDL cholesterol (34%), body weight (46%). It also significantly reduced aortic cholesterol and thiobarbituric acid reactive substances and there was a significant increase of reduced glutathione. Taurine significantly increased fecal bile acids which may have resulted in significant decrease of serum cholesterol. Aortic lesion index was significantly decreased in the taurine administered group suggesting the antiatherogenic effect of taurine. It is concluded that taurine attenuated the atherogenesis possibly by its hypocholesterolemic and antioxidant property.

Influence of intragastric perfusion of aqueous spice extracts on acid secretion in anesthetized albino rats

BACKGROUND

The effect of spices on gastric acid secretion is variable. Their mechanism of action is also not well established.

AIM

To study the effect of spices on gastric acid secretion in anesthetized rats.

METHODS

Aqueous extracts (10% w/v) of red pepper (Capsicum annuum), fennel (Foeniculum vulgare), omum/ajwan (Carum copticum), cardamom (Elettaria cardamomum), black pepper (Piper nigrum), cumin (Cuminum cyminum) and coriander (Coriandrum sativum) were prepared. The stomach of pentobarbitone-anesthetized rats was perfused at 0.15 mL/min with aqueous extracts of spice or acetylcholine (1 microgram/mL or 10 micrograms/mL solutions, in 40 min blocks, twice in each experiment bracketed by saline perfusions. The acid content in the samples was estimated by titration with 0.1N NaOH with phenolphthalein as indicator. Atropine 1 microgram/mL was added to the perfusion fluid in 28 experiments. In 32, acute gastric mucosal injury was induced by leaving aspirin 125 mg/Kg in the stomach for 2 h before perfusion.

RESULTS

All the spices tested increased acid secretion in the following declining order: red pepper, fennel, omum, cardamom, black pepper, cumin, coriander. Red pepper increased acid secretion (mean [SEM] 0.93 [0.16] mL 0.1N HCl) to about 7 times the basal secretion (0.14 [0.05]; p < 0.005). The increase in acid secretion by the other spices was as follows: fennel 0.42 (0.11) mL 0.1 N HCl from basal secretion (0.12 [0.03]) (p < 0.02); omum 0.33 (0.05) from 0.09 (0.02) (p < 0.01); cardamom 0.28 (0.04) from 0.10 (0.03) (p < 0.005); black pepper 0.19 (0.03) from 0.04 (0.01) (p < 0.005); cumin 0.12 (0.02) from 0.08 (0.01) (p < 0.05); coriander 0.18 (0.03) from 0.09 (0.02) (p < 0.005). Atropine abolished the acid secretion induced by acetylcholine and significantly reduced acid induction by red pepper, omum and coriander, but not that by fennel. In experiments with aspirin-induced mucosal injury the basal acid secretion was low; acid secretion by red pepper and fennel was reduced significantly, but not that by acetylcholine. Cumin and coriander increased acid secretion in injured stomachs.

CONCLUSION

The spices tested increased gastric acid secretion, in some by a cholinergic mechanism but by other mechanism(s) as well. Red pepper produced maximum increase in acid secretion, but this was significantly reduced in injured stomachs. Cumin and coriander increased gastric secretion in injured stomachs.

The neuregulin receptor ErbB-4 interacts with PDZ-containing proteins at neuronal synapses

Neuregulins regulate the expression of ligand- and voltage-gated channels in neurons and skeletal muscle by the activation of their cognate tyrosine kinase receptors, ErbB 1-4. The subcellular distribution and mechanisms that regulate the localization of ErbB receptors are unknown. We have found that ErbB receptors are present in brain subcellular fractions enriched for postsynaptic densities (PSD). The ErbB-4 receptor is unique among the ErbB proteins because its C-terminal tail (T-V-V) conforms to a sequence that binds to a protein motif known as the PDZ domain. Using the yeast two-hybrid system, we found that the C-terminal region of ErbB-4 interacts with the three related membrane-associated guanylate kinases (MAGUKs) PSD-95/SAP90, PSD-93/chapsyn-110, and SAP 102, which harbor three PDZ domains, as well as with beta(2)-syntrophin, which has a single PDZ domain. As with N-methyl-D-aspartate (NMDA) receptors, ErbB4 interacts with the first two PDZ domains of PSD-95. Using coimmunoprecipitation assays, we confirmed the direct interactions between ErbB-4 and PSD-95 in transfected heterologous cells, as well as in vivo, where both proteins are coimmunoprecipitated from brain lysates. Moreover, evidence for colocalization of these proteins was also observed by immunofluorescence in cultured hippocampal neurons. ErbB-4 colocalizes with PSD-95 and NMDA receptors at a subset of excitatory synapses apposed to synaptophysin-positive presynaptic terminals. The capacity of ErbB receptors to interact with PDZ-domain proteins at cell junctions is conserved from invertebrates to mammals. As discussed, the interactions found between receptor tyrosine kinases and MAGUKs at neuronal synapses may have important implications for activity-dependent plasticity.

Developmental brain injury associated with abnormal play behavior in neonatally Borna disease virus-infected Lewis rats: a model of autism

Play behavior, nonsocial exploratory activity, and nonplay social interaction were observed in male juvenile Lewis rats with brain developmental injury following neonatal infection with Borna disease virus (BDV). These behaviors were tested using the 'intruder-resident' paradigm, with social isolation of residents for six days prior to testing. Four experimental pairings of infected (BDV) and uninfected (NL) rats were studied as follows: NL-NL; NL BDV; BDV NL; and BDV-BDV (the first member is the resident, the second member is the intruder). Observation of social activities was carried out for 10 min on two consecutive days. Nonsocial exploratory activity (e.g. ambulation and rearing) was similar in BDV and NL residents. Duration of nonplay social investigation (e.g. sniffing, approach, and follow) was higher in BDV residents as compared to NL residents when tested on the first test day. On the second day, all rats showed similar level of nonplay social interaction. When confronted with NL intruders, NL residents exhibited significantly more play behavior compared to the NL-BDV, BDV NL and BDV-BDV pairs, when play behavior was measured by the number of 'pins'. Moreover, irrespective of a type of intruder, NL residents demonstrated higher play soliciting behavior than BDV residents, indicating attenuated readiness to play in BDV-infected rats. The number of pins and play solicitations in BDV-NL pairs significantly increased over the two days of testing, while play activity in NL-BDV pairs declined on the second test day. This pattern suggests that the degree of social reinforcement on the first day of testing affected the level of play on the second day. These data demonstrate deficits in play behavior and other social interactions following BDV-associated developmental brain injury, thus supporting the value of the neonatally BDV-infected rat as an animal model of autism.

Use of rat jejunum for assay of acetylcholine

Experiments were carried out to determine the advantage in using isolated rat jejunum in the assay of acetylcholine (ACh) in preference to other tissues. Rat jejunum was found to be sensitive to ACh 0.01 micrograms, 5-hydroxytryptamine (5HT) 0.2 to 0.5 microgram and least sensitive to histamine. (Ach greater than 5HT greater than histamine).

An abinitio and ion cyclotron resonance study of the protonation of borazine

The gas phase ion–molecule reactions and proton affinity of borazine have been investigated by both theoretical ab initio and ion cyclotron resonance techniques. The experimental proton affinity has been determined from competitive proton transfer equilibria with standard reference bases and found to be 196.4 ± 0.2 kcal/mol. Ion–molecule reaction schemes for reaction of borazine molecular ions have been proposed. Ab initio calculations find the proton affinity of borazine to be 203.4 kcal/mol and the most energetically favorable structure of the borazinium ion is one in which very little structural change occurs relative to neutral borazine with the exception of the geometry about the protonated nitrogen atom. Charge distributions and bond lengths are used to explain bonding changes upon protonation.

Gangrene of the tongue following self-application of a rubber band

A case of dry gangrene of the tongue due to self-application of an elastic rubber band in a mentally retarded child is described. As far as is known, no such case of gangrene of the tongue has been described in the English literature.