Preclinical modeling of a phase 0 clinical trial protocol

14058

Background: The Exploratory IND program initiated at NCI (“Phase 0”) is designed to evaluate the pharmacodynamic effects (PD) of candidate drugs at the molecular level in the clinic. Trials employ patient biopsies and surrogate tissues (e.g. PBMCs) to determine the quantitative effect of the agent on its putative target, after a minimum number of doses. The approach requires repeated biopsy of the tumor, an understanding of the time-effect window, and some knowledge of the dose level likely to cause a measurable drug effect. Methods: Prior to initiating a Phase 0 study of the PARP (PolyAdenosyl-Ribose Polymerase) inhibitor, ABT-888, we developed a pre-clinical model to mirror the clinical protocol. Colo 829 and A375 xenografts in athymic nude [nu/nu (NCr)] mice were examined for time and dose effect on PARP using a validated, quantitative PAR assay. Extracts of entire xenografts, quartered xenografts and 18 gauge needle biopsies were examined for variability of baseline and post-treatment PAR levels. Results were cross-checked with Western analysis for polyADP-Ribose (PAR)-labeled proteins in treated mice. Pharmacokinetics (PK) were modeled using plasma drug levels. Additional studies examined the influence of previous biopsy, contralateral biopsy, vehicle treatment, and general anesthesia on PAR in xenografts. Results: A single dose of ABT-888 produced a significant decrease in intracellular PAR levels that could be measured 2 to 6 hours post-dose. PAR levels and drug effect on PAR levels were not influenced by repeated needle biopsies. Variation across xenografts was random for single and bilateral xenograft animal models in the ABT-888 treated, vehicle- and topotecan-treated control groups. Animal handling and socialization appeared to elevate baseline PAR levels, which could confound analysis of study results. Conclusions: Pre-clinical modeling of a specific Phase 0 clinical protocol for drug effects and biological variability provided valuable insights into the development, refinement, and analysis of the currently-active NCI Phase 0 clinical trial of ABT-888. Animal studies were conducted in an AAALAC approved facility under an approved IACUC protocol. Funded by NCI Contract N01-CO-12400.

No significant financial relationships to disclose.

Effect of wine phenolics on cytokine-induced C-reactive protein expression

BACKGROUND

Elevation of C-reactive protein (CRP) levels in blood was recognized as one of the cardiac disease risk factors. Consumption of wine is shown to reduce the risk from heart disease and improve longevity.

OBJECTIVES

In the present study, we evaluated the effect of various wine polyphenolic compounds and several active synthetic derivatives of resveratrol on the inflammatory cytokines (IL-1beta + IL-6)-induced CRP expression in Hep3B cells.

RESULTS

Among the wine phenolics tested, quercetin and resveratrol, in a dose-dependent manner, suppressed cytokine-induced CRP expression. Two of the synthetic derivatives of resveratrol, R3 and 7b, elicited a fiftyfold higher suppressive effect compared with resveratrol. The inhibitory effects of resveratrol and its derivatives on CRP expression were at the level of mRNA production. Investigation of signaling pathways showed that the cytokines induced the phosphorylation of p38 and p44/42 MAP kinases. Inhibitors of p38 and p44/42 mitogen-activated protein kinase (MAPK) activation inhibited CRP expression, implicating the involvement of both pathways in cytokine-induced CRP expression. These data revealed a previously unrecognized role of the p44/42 MAPK signaling pathway in CRP expression. Wine polyphenolics or the synthetic compounds of resveratrol did not affect cytokine-activated phosphorylation of these MAPKs.

CONCLUSIONS

Wine phenolics inhibit CRP expression; however, to do so, they do not utilize the MAPK pathways.

14th International HLA and Immunogenetics Workshop: Report on joint study on MHC and infection

The 'MHC and Infection' study of the 14th International HLA and Immunogenetics Workshop was undertaken to evaluate the contribution of specific variants of major histocompatibility complex (MHC) and non-MHC genes that are specifically associated with higher probabilities of infection, disease severity, and progression in different populations.

14th IHIWS MHC and Infection Study: summary and conclusions

International collaborative efforts through histocompatibility workshops have helped greatly in collating useful data on interpopulation differences in genetic susceptibility to mycobacterial and viral infections. These are imperative in exploring the genetic basis of disease pathogenesis and host resistance. Because infectious diseases involve multigenic complex traits, several genetic variants contribute modifying effects on the disease but disease outcome depends on the net relative hazards of individual genetic loci taken together. Further because occurrence of genetic variants varies in a population-specific manner, it becomes even more complicated to show genetic influences across populations. For this, large study cohorts representing different ethnicities are needed. Information thus gained could lead to the development of more effective vaccine design to combat or diminish the emergence of pathogenic multidrug resistant forms.

Association of variants in theIL12Bgene with leprosy and tuberculosis

There is a great range in outcomes after mycobacterial infections, and this is probably due to individual variation in immune responses. One of the key cytokine regulators of the immune response is interleukin (IL-) 12. The IL12B gene encodes the p40 chain of both IL-12 and IL-23 and it has two major variant sites at which different alleles are associated with increased levels of gene expression and with susceptibility to a range of immune-related diseases. We hypothesized that IL12B variants associated with increased expression would be as associated with susceptibility to persistent mycobacterial infection. We tested this hypothesis by genotyping Indian subjects, having either leprosy or tuberculosis (TB), as well as ethnically matched controls. Subjects with leprosy were less likely to have the 3'UTR genotype associated with lower IL12B expression (P= 0.001). Subjects with TB were not only more likely to have the high-expressing IL12B promoter genotype (P= 0.01) but also more likely to have this in the same haplotype with the high expressing 3'UTR allele (P= 0.0009). These results suggest these infectious diseases may be improved by modulating IL-l2p40 production.

Frequency distribution of cytokine gene polymorphisms in the healthy North Indian population

The allelic and genotype frequencies corresponding to 22 single nucleotide polymorphisms (SNPs) in 13 cytokine genes interleukin (IL) 1-alpha (T/C -889), IL1-beta (C/T -511, T/C +3962), IL12 (C/A -1188), interferon-gamma (A/T UTR 5644), transforming growth factor-beta (C/T codon 10, G/C codon 25), tumour necrosis factor-alpha (G/A -308, G/A -238), IL2 (T/G -330, G/T +160), IL4 (T/G -1098, T/C -590, T/C -33), IL6 (G/C -174, G/A nt 565), IL10 (G/A -1082, C/T -819, C/A -592), IL1R (C/T pst11970), IL1RA (T/C mspa111100) and IL4RA (G/A +1902) were determined in 130 healthy North Indian subjects. All genomic typings were performed with polymerase chain reaction with sequence-specific assays. An analysis of the allelic and haplotype frequencies in the North Indian population showed a good fit with the Hardy-Weinberg equilibrium for most of the SNPs. The data can be used for anthropological comparisons, as well as for association studies with different diseases and for use in transplant situations involving acute and chronic rejection.

RBx 7796: A novel inhibitor of 5-lipoxygenase

OBJECTIVE

To evaluate the pharmacological profile of RBx 7,796, a novel 5-lipoxygenase inhibitor.

MATERIALS AND METHODS

RBx 7,796 was evaluated for 5- lipoxygenase inhibitory potential using human recombinant enzyme and profiled for selectivity against 12 and 15 lipoxygenase. RBx 7,796 was evaluated in cell based assay for inhibition of A23,187 induced LTB(4) release from isolated neutrophils. Ex vivo activity was evaluated for inhibition of A23,187 induced LTB(4) release in blood from treated rats. In vivo efficacy of RBx 7,796 was profiled in LPS induced neutrophilia model in rats and also in ovalbumin induced bronchoconstriction and airway inflammation models in guinea pigs.

RESULTS

RBx 7,796, a novel chemotype, showed competitive inhibition of 5-lipoxygenase enzyme with an IC(50) of 3.5 +/- 1.1 microM. RBx 7,796 offered >100 fold selectivity against other related enzymes - 12 and 15 lipoxygenase. RBx 7,796 inhibited release of LTB(4) from human and rat neutrophils in vitro. Upon administration to rats, RBx 7,796 inhibited A23,187 induced LTB(4) release from rat neutrophils. Upon repeated administration, dosed once daily, RBx 7,796 inhibited LPS induced neutrophil influx in rat airway. RBx 7,796 also inhibited allergen induced bronchoconstriction and eosinophil influx in guinea pig airway in a dose dependent manner.

CONCLUSION

The results suggest that RBx 7,796, a novel chemotype, is an orally efficacious inhibitor of 5-lipoxygenase enzyme that is effective against both neutrophilic and eosinophilic airway inflammation and shows potent inhibition with once daily administration.

Inhibition of oxidative stress and cytokine activity by curcumin in amelioration of endotoxin-induced experimental hepatoxicity in rodents

The present study is aimed at investigating the effect of curcumin (CMN) in salvaging endotoxin-induced hepatic dysfunction and oxidative stress in the liver of rodents. Hepatotoxicity was induced by administering lipopolysaccharide (LPS) in a single dose of 1 mg/kg intraperitoneally to the animals, which were being treated with CMN daily for 7 days. Liver enzymes serum alanine aminotransferase (ALT), serum aspartate aminotransferase (AST) and alkaline phosphatase (ALP), total bilirubin and total protein were estimated in serum. Oxidative stress in liver tissue homogenates was estimated by measuring thiobarbituric acid reactive substances (TBARS), glutathione (GSH) content and superoxide dismutase (SOD) activity. Serum and tissue nitrite was estimated using Greiss reagent and served as an indicator of NO production. A separate set of experiments was performed to estimate the effect of CMN on cytokine levels in mouse serum after LPS challenge. LPS induced a marked hepatic dysfunction evident by rise in serum levels of ALT, AST, ALP and total bilirubin (P < 0.05). TBARS levels were significantly increased, whereas GSH and SOD levels decreased in the liver homogenates of LPS-challenged rats. CMN administration attenuated these effects of LPS successfully. Further CMN treatment also regressed various structural changes induced by LPS in the livers of rats and decreased the levels of tumour necrosis factor-alpha and interleukin-6 in mouse plasma. In conclusion, these findings suggest that CMN attenuates LPS-induced hepatotoxicity possibly by preventing cytotoxic effects of NO, oxygen free radicals and cytokines.

Polymorphism in L-Selectin, E-Selectin and ICAM-1 Genes in Asian Indian Pediatric Patients With Celiac Disease

Celiac disease (CD) follows an autoimmune course in which both genetic and environmental factors contribute to its development. A strong association with HLA class II molecules, predominantly HLA-DQ2, has been reported in most ethnic groups with CD. The aim of this study was to determine if genetic polymorphisms in L-selectin, E-selectin, and intercellular adhesion molecule-1 (ICAM-1) have any correlation with CD. We investigated 5 mutations, namely F206L in L-selectin, S128R and L554F in E-selectin, and G241R and K469E in ICAM-1, in 37 North Indian pediatric patients with CD. A significant increase in allele frequencies of 128R of E-selectin and the associated genotype SR was observed in patients. No significant differences were observed in the F206L polymorphism of L-selectin, or the G241R and E469K polymorphisms in the ICAM-1 gene in CD. This study illustrates that selectin gene polymorphism might contribute to the genetic background of CD and invites further investigation relevant to understanding the mechanisms underlying the immunopathogenesis of this autoimmune disease.

Lung cancer resection does not change characteristic serum proteomic profiles

10051

Background: Surface-enhanced laser desorption/ionisation time of flight mass spectrometry (SELDI-TOF-MS) has been proposed as a method for determining characteristic serum proteomic profiles that permit discrimination between cancer and non-cancer patients. The aim of this study was to test in a group of lung cancer patients the hypothesis, that these profiles ‘return to normal’ following tumour resection, as would be expected if they behave as conventional serological tumour makers. Methods: Serum samples were collected from 39 patients with non-small cell lung cancer, 1 day pre-surgery, 1 day post-surgery and, for 17 of these, approximately three months later; samples were also obtained from 38 non-cancer control subjects. All samples were subjected to SELDI-TOF-MS analysis on CM10 chips. Students t-tests were used to identify differentially expressed peaks in the profiles. Results: The SELDI profiles of the lung cancer sera compared to non-lung-cancer controls showed 19 significantly differentially expressed peaks (p<0.01), 14 of which were used to develop a neural network capable of discriminating between the two groups. Analysis of proteomic features showed that despite the absence of cancer in patients 3-months post-surgery, no statistically significant differences could be detected between the pre-treatment and 3-month post-operative samples from the same patients, including the 19 features that were found to discriminate between lung and non-lung cancer. One of the proteins significantly decreased in the serum of lung cancer patients was identified as transthyretin. Conclusions: SELDI can detect differentially expressed protein peaks characteristic of lung cancer compared to non-lung cancer patients but following surgical resection of the cancer, neither the pattern nor the individual peaks revert to the levels observed in non-lung cancer patients. The hypothesis that such differences would revert to normal after tumour removal was not supported. Work funded by Cancer Research UK

No significant financial relationships to disclose.

Switching from methadone to a different opioid: What is the equianalgesic dose ratio?

8617

Background: Methadone (ME) is a highly effective opioid agonist used for difficult pain syndromes. However, the rotation from ME to another opioid may be difficult because of the absence of a uniformly accepted conversion ratio. Methods: We retrospectively reviewed consecutive medical records of Pts undergoing an opioid rotation from ME to an alternative opioid. For inclusion, Pts were required to have received ME for at least 3 days prior to the switch and reach a stable dose of the alternative opioid(s) during 7 days following. Stable dose was defined as a 30% or less change in opioid dose from one day to the next. For purposes of analysis, on the day before the switch, doses, were divided into ME doses and the oral morphine equivalent daily dose (MEDD), based on medication and route of all other opioids taken on that day, using standard equinalgesic tables. All doses after the switch were converted to the MEDD. For Pts receiving ME and a second opioid prior to the switch, the MEDD of the second opioid was subtracted from the MEDD calculated for the day when stable dose was reached. The remainder was used to calculate the equianalgesic raio with the previous ME dose. Results: Records on 39 Pts met inclusion criteria. Excluded from analysis were 5 Pts who were restarted on ME in < 8 days, 2 whose opioid dose markedly decreased of post switch, and 3 due to concerns about reliability of multiple routes used for fentanyl. Data from 29 Pts, 10 female, mean age 48 ±14.4 were evaluable. The ratio for: oral ME to MEDD was 1:4.7 (CL 3.0–6.5)(n=16), IV ME to MEDD was 1:13.5 (CL6.6–20.5)(n=13), p=0.06. ME dose is significantly correlated to stable MEDD after switching opioids for both ME IV and oral (Spearman=0.86,p=0.0001 and Spearman=0.72, p=0.0024, respectively. Mean day of achieving stable dose was on day 2.5 ±0.2 for IV ME and day 2.6±0.3 for oral ME. Conclusions: These dose ratios are new findings that will assist in switching Pts more safely to alternative opioids, when side effects or pain problems occur.An important difference in analgesic potency appears to exist between IV and oral ME. Further research with prospective studies is required.

No significant financial relationships to disclose.

The impact of physician’s sequence [1st vs 2nd] and posture [sitting vs standing] on cancer patients’ physician preference and perception of compassion

18513

Background: Our group previously found in a cross-over RCT in 69 advanced cancer patients [P] that the sitting posture was preferred; we also found that patients consistently chose the physician [MD] they observed in 2nd order [ASCO 2003:2958]. The effect of sequence on MD preference and perception of compassion had not been reported before. The purpose of this study was to assess if P preferred MD seen in 2nd order after controlling for posture. Methods: Advanced cancer P were randomized to observe 2 9-minute videos of a P/MD interaction. Both videos were identical except for the posture of the MD [sitting versus standing]. After a 2–3 minute assessment P were crossed-over into viewing the opposite video. Investigators were blinded to the type of video observed. P were blinded to the purpose of the study and difference between videos. Results: 168 P [98%] were evaluable. The mean perception of compassion [0 = worst, 50 = best] was 29 ± 13 for the 1st MD versus 33 ± 11 for the 2nd MD [p < 0.001]. P also preferred sitting [33 ± 11] versus standing [29 ± 12, p < 0.001]. The overall impression [0 = worst, 10 = best] for the MD seen 2nd versus 1st was 6.5 ± 2.3 versus 5.7 ± 2.7 [p ≤ 0.001]. All differences in response were independent on posture. 119/168 P [71%] perceived a difference between the 2 MDs and this difference was considered ≥ moderately important in 95 P [80%]. 76/168 P preferred the 2nd MD [45%, 95% CI, 38–53], 38/168 P preferred the 1st MD [23%, 95% CI, 16–29], and 54/168 P had no preference [32%, 95% CI, 25–39]. 49/114 P who expressed a preference perceived their preferred MD had spent more time with the P [43%]. 87/168 P preferred their MD to sit [52%] but they considered posture more important than time in 23 cases [20%], friendliness in 18 [15%], patience in 16 [14%], caring in 15 [14%], and respect in 18 [16%]. Conclusions: P prefer MDs they see in 2nd order, they have an overall better impression of them and consider them more compassionate, and they perceive that they spent more time with their P, independently on the MD’s chosen posture. Most P also prefer MDs to sit but posture is rated as a relatively low priority in P/MD communication. These findings are important for clinical care and trial participation.

No significant financial relationships to disclose.

Giant nerve sheath tumour: report of six cases

Giant nerve sheath tumour is a rare tumour originating from the nerve sheath. It differs from the conventional nerve sheath tumour only by the size these tumours can reach. There are two main type of tumours that occur in the nerve sheath which include neurofibroma and schwannoma. The current views are that schwannomas arise from the progenitor of the schwann cell. Whereas the neurofibroma series probably arise from a mesenchymal origin closer to a fibroblast. We report on six cases of nerve sheath tumour that occur in the spinal and paraspinal region that presented to us over a 5 year period.

Robotics in neurosurgery: state of the art and future technological challenges

The use of robotic technologies to assist surgeons was conceptually described almost thirty years ago but has only recently become feasible. In Neurosurgery, medical robots have been applied to neurosurgery for over 19 years. Nevertheless this field remains unknown to most neurosurgeons. The intrinsic characteristics of robots, such as high precision, repeatability and endurance make them ideal surgeon's assistants. Unfortunately, limitations in the current available systems make its use limited to very few centers in the world. During the last decade, important efforts have been made between academic and industry partnerships to develop robots suitable for use in the operating room environment. Although some applications have been successful in areas of laparoscopic surgery and orthopaedics, Neurosurgery has presented a major challenge due to the eloquence of the surrounding anatomy. This review focuses on the application of medical robotics in neurosurgery. The paper begins with an overview of the development of the medical robotics, followed by the current clinical applications in neurosurgery and an analysis of current limitations. We discuss robotic applications based in our own experience in the field. Next, we discuss the technological challenges and research areas to overcome those limitations, including some of our current research approaches for future progress in the field.

005.Efficiency of nuclear import of the chromatin-remodelling factor SRY is critical for sex determination

15% of cases of human XY sex reversal are due to mutations in SRY (sex determining region on the Y chromosome), many of which map to one of SRY’s two independently acting nuclear localization signals (NLSs) flanking its DNA binding domain. The C-terminal NLS (C-NLS) targets SRY to the nucleus through a ‘conventional’ pathway dependent on the nuclear import receptor importin-β (Imp-β). No importin has been shown to bind the N-terminal NLS (N-NLS), but it is known to interact with the Ca2+-binding protein calmodulin (CaM). We examined seven distinct missense mutations in the SRY NLSs from XY sex-reversed human females for effects on nuclear import and ability to interact with CaM/Imp-β1. All mutations were found to result in reduced nuclear localization in transfected testicular cells compared to wild type. The CaM antagonist, calmidazolium chloride (CDZ), was found to significantly reduce SRY nuclear accumulation, indicating a dependence of SRY nuclear import on CaM. Intriguingly, N-NLS mutants were resistant to CDZ’s effects, implying a loss of interaction with CaM; this was confirmed directly by in vitro binding experiments using recombinantly expressed protein. Either impaired CaM or Imp-β1 binding can thus be the basis of sex-reversal in human patients. Our results implicate a CaM-dependent nuclear import pathway for SRY mediated by the N-NLS that, together with the C-NLS, is required to achieve threshold levels of SRY in the nucleus for male sex determination.

Dominant negative effect of novel mutations in pyruvate kinase-M2

The natural mutations observed in pyruvate kinase (PK)-M2, a homotetramer isozyme, in this study correlated with the differential activity of the enzyme in a dominant negative manner in B-lymphoblastoid cells, established from two Bloom syndrome (BS) patients, BS1 and BS3 by 50 and 90%, respectively; and by 75% in the freshly obtained PHA stimulated lymphocytes of a BS patient diagnosed for the first time in India. A gene screen involving the critical domains of the PK-M gene in BS cells resulted in the observation of a missense mutation in BS1 and the BS patient and a frame shift mutation in BS3, in exon-10, coding for the intersubunit contact domain (ISCD) of the PK-M2 protein. Apart from these mutations, other variations in this region of the gene, both in normal and BS cells, did not affect the enzyme activity, since these were silent. Computer-based modeling studies of the PK-M2 protein with each mutation was suggestive of a changed interaction between two domains within a subunit in BS1, a gross structural change in BS3, and a changed interaction between two subunits of the tetramer in the BS patient. An absence of such mutations in other regions of the PK-M2 gene in normal subjects and in the randomly chosen unrelated genes in the DNA from BS cell lines and the cells from the BS patient, authenticated the presence of the observed mutations in Bloom syndrome cells. A correlation observed between the differential enzyme activity and the nature of mutation in the intersubunit contact domain (ISCD) region of the PK-M2 gene was interesting, and indicted how the site and the nature of mutation in a heterozygous state could influence the enzyme activity differentially and in a dominant negative manner. The importance of these mutations in Bloom syndrome cells, however, remains to be elucidated, and can only be conjectured.

Intergeneric hybridization between Erucastrum cardaminoides and two diploid crop Brassica species

Two intergeneric hybrids involving wild species Erucastrum cardaminoides (2 n=18, E(cd) E(cd)) and two crop brassica species, Brassica rapa (2 n=20, AA) and B. nigra (2 n=16, BB), were synthesized through in vitro sequential ovary culture. Morphological, molecular and cytological studies were conducted to establish their hybridity. Both hybrids, though morphologically distinct, were intermediate phenotypically between their respective parents. Cytological analysis of the E. cardaminoides x B. rapa hybrid (2 n=19), revealed the occurrence of 17 I+1 II at diakinesis/metaphase in the majority (28%) of the pollen mother cells (PMCs), whereas in E. cardaminoides x B. nigra hybrid (2 n=17), 13 I+2 II was the predominant (32%) meiotic configuration. A maximum of 5 II was recorded in both hybrids, indicating homoeologous pairing in the respective combined genomes. Chromosome doubling by colchicine application gave rise to two new amphiploids (AA E(cd)E(cd) and BB E(cd)E(cd)) having normal chromosome pairing and pollen fertility. The occasional occurrence of one quadrivalent in the amphiploids confirmed partial homoeology between the E(c) and A/B genomes. The E. cardaminoides x B. nigra hybrid and amphiploid appeared to be tolerant to alternaria blight under field conditions.