Abstract 1361: Fragment based drug discovery of selective inhibitors of Fibroblast Growth Factor Receptor (FGFR)

Recent data in a number of tumour types has implicated Fibroblast Growth Factor (FGF) and Fibroblast Growth Factor receptor (FGFR) signalling as being key to the molecular pathology of cancer.

A fragment screening campaign was conducted against the tyrosine kinase domain of FGFR1 to detect low molecular weight compounds that bound to the hinge region of the kinase. The screening produced several fragment inhibitors (molecular weight <250 Da) in the micromolar range and their binding modes were confirmed by X-ray crystallography. We selected an imidazo[1,2-a]pyridine fragment that was 120 uM versus FGFR3 in the kinase inhibition bioassay. Subsequently, in the fragments-to-leads stage a detailed structural understanding of the binding interactions between the fragment and its protein kinase target, using X-ray crystallography, led to the identification of a 0.003 uM inhibitor of FGFR3 in the kinase bioassay, with significant selectivity versus VEGFR2 and FLT3.

The poster will focus on the description of previously undescribed compounds bearing an imidazo[1,2-a]pyridine core scaffold where selectivity versus other protein kinases, for example FLT3, is obtained using the X-ray crystal structure and structure-based design. In summary we will illustrate how X-ray crystallography and fragment-based drug design (FBDD) can be used to discover compounds with activity in an FGFR driven xenograft model when dosed by the oral route.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1361. doi:10.1158/1538-7445.AM2011-1361

Localization of Sonic hedgehog secreting and receiving cells in the developing and adult rat adrenal cortex

Sonic hedgehog signaling was recently demonstrated to play an important role in murine adrenal cortex development. The organization of the rat adrenal differs from that of the mouse, with the zona glomerulosa and zona fasciculata separated by an undifferentiated zone in the rat, but not in the mouse. In the present study we aimed to determine the mRNA expression patterns of Sonic hedgehog and the hedgehog signaling pathway components Patched-1 and Gli1 in the developing and adult rat adrenal. Sonic hedgehog expression was detected at the periphery of the cortex in cells lacking CYP11B1 and CYP11B2 expression, while signal-receiving cells were localized in the overlying capsule mesenchyme. Using combined in situ hybridization and immunohistochemistry we found that the cells expressing Sonic hedgehog lie between the CYP11B2 and CYP11B1 layers, and thus Sonic hedgehog expression defines one cell population of the undifferentiated zone.

Search for effects beyond the born approximation in polarization transfer observables in e(over→)p elastic scattering

Intensive theoretical and experimental efforts over the past decade have aimed at explaining the discrepancy between data for the proton electric to magnetic form factor ratio, G(E)/G(M), obtained separately from cross section and polarization transfer measurements. One possible explanation for this difference is a two-photon-exchange contribution. In an effort to search for effects beyond the one-photon-exchange or Born approximation, we report measurements of polarization transfer observables in the elastic H(e[over →],e(')p[over →]) reaction for three different beam energies at a Q(2)=2.5  GeV(2), spanning a wide range of the kinematic parameter ε. The ratio R, which equals μ(p)G(E)/G(M) in the Born approximation, is found to be independent of ε at the 1.5% level. The ε dependence of the longitudinal polarization transfer component P(ℓ) shows an enhancement of (2.3±0.6)% relative to the Born approximation at large ε.

HER2 phosphorylation is maintained by a PKB negative feedback loop in response to anti-HER2 herceptin in breast cancer

A feedback loop maintains HER2 receptor signalling and cell survival in response to Herceptin treatment in HER2-positive breast cancers, but this Herceptin resistance may be bypassed by pan-HER inhibitors.

Herceptin (trastuzumab) is used in patients with breast cancer who have HER2 (ErbB2)–positive tumours. However, its mechanisms of action and how acquired resistance to Herceptin occurs are still poorly understood. It was previously thought that the anti-HER2 monoclonal antibody Herceptin inhibits HER2 signalling, but recent studies have shown that Herceptin does not decrease HER2 phosphorylation. Its failure to abolish HER2 phosphorylation may be a key to why acquired resistance inevitably occurs for all responders if Herceptin is given as monotherapy. To date, no studies have explained why Herceptin does not abolish HER2 phosphorylation. The objective of this study was to investigate why Herceptin did not decrease HER2 phosphorylation despite being an anti-HER2 monoclonal antibody. We also investigated the effects of acute and chronic Herceptin treatment on HER3 and PKB phosphorylation in HER2-positive breast cancer cells. Using both Förster resonance energy transfer (FRET) methodology and conventional Western blot, we have found the molecular mechanisms whereby Herceptin fails to abolish HER2 phosphorylation. HER2 phosphorylation is maintained by ligand-mediated activation of EGFR, HER3, and HER4 receptors, resulting in their dimerisation with HER2. The release of HER ligands was mediated by ADAM17 through a PKB negative feedback loop. The feedback loop was activated because of the inhibition of PKB by Herceptin treatment since up-regulation of HER ligands and ADAM17 also occurred when PKB phosphorylation was inhibited by a PKB inhibitor (Akt inhibitor VIII, Akti-1/2). The combination of Herceptin with ADAM17 inhibitors or the panHER inhibitor JNJ-26483327 was able to abrogate the feedback loop and decrease HER2 phosphorylation. Furthermore, the combination of Herceptin with JNJ-26483327 was synergistic in tumour inhibition in a BT474 xenograft model. We have determined that a PKB negative feedback loop links ADAM17 and HER ligands in maintaining HER2 phosphorylation during Herceptin treatment. The activation of other HER receptors via ADAM17 may mediate acquired resistance to Herceptin in HER2-overexpressing breast cancer. This finding offers treatment opportunities for overcoming resistance in these patients. We propose that Herceptin should be combined with a panHER inhibitor or an ADAM inhibitor to overcome the acquired drug resistance for patients with HER2-positive breast cancer. Our results may also have implications for resistance to other therapies targeting HER receptors.

HER2 (ErbB2) is a surface protein and member of the epidermal growth factor receptor (EGFR) family that is overexpressed in approximately one-fifth of breast cancers. HER2-positive breast tumours tend to be very aggressive, and patients with this type of tumour have a poor prognosis. A therapeutic monoclonal antibody called trastuzumab (Herceptin) has been designed to block HER2 signalling and is used as a treatment for patients with HER2-positive breast cancer. However, recent studies have shown that Herceptin does not decrease HER2 activation. This may be why patients invariably develop resistance if treated with Herceptin monotherapy. To date, no study has explained why Herceptin cannot abolish HER2 signalling despite being an anti-HER2 monoclonal antibody. We have found that Herceptin switches on a feedback loop that increases the production of the ADAM17 protein, a protease that in turn releases the growth factors that activate HER (ErbB) receptors. These growth factors activate HER2 and also the other members of the HER receptor family—EGFR, HER3 and HER4—in such a way as to maintain HER2 activation and cell survival in HER2-positive breast cancer cells. We have found that when Herceptin is provided in combination with ADAM17 inhibitors, the feedback loop is abrogated in cells. Furthermore, a pan-HER inhibitor that decreases the activation of other HER receptors can also inhibit the feedback loop and decrease HER2 activation when used in combination with Herceptin. We further demonstrated that the combination therapy of Herceptin with a pan-HER inhibitor is more effective than Herceptin alone in an animal model of breast cancer. We believe our results offer treatment strategies that may help overcome acquired Herceptin resistance in patients with HER2-positive breast cancer.

Characterization of aryl hydrocarbon receptor interacting protein (AIP) mutations in familial isolated pituitary adenoma families

Familial isolated pituitary adenoma (FIPA) is an autosomal dominant condition with variable genetic background and incomplete penetrance. Germline mutations of the aryl hydrocarbon receptor interacting protein (AIP) gene have been reported in 15–40% of FIPA patients. Limited data are available on the functional consequences of the mutations or regarding the regulation of the AIP gene. We describe a large cohort of FIPA families and characterize missense and silent mutations using minigene constructs, luciferase and β-galactosidase assays, as well as in silico predictions. Patients with AIP mutations had a lower mean age at diagnosis (23.6±11.2 years) than AIP mutation-negative patients (40.4±14.5 years). A promoter mutation showed reduced in vitro activity corresponding to lower mRNA expression in patient samples. Stimulation of the protein kinase A-pathway positively regulates the AIP promoter. Silent mutations led to abnormal splicing resulting in truncated protein or reduced AIP expression. A two-hybrid assay of protein–protein interaction of all missense variants showed variable disruption of AIP-phosphodiesterase-4A5 binding. In summary, exonic, promoter, splice-site, and large deletion mutations in AIP are implicated in 31% of families in our FIPA cohort. Functional characterization of AIP changes is important to identify the functional impact of gene sequence variants. Hum Mutat 31:1–11, 2010. © 2010 Wiley-Liss, Inc.

The Bio-Tribological Characteristics of Synthetic Tissue Grafts

The use of synthetic connective tissue grafts became popular in the mid-1980s, particularly for anterior cruciate ligament reconstruction; however, this trend was soon changed given the high failure rate due to abrasive wear. More than 20 years later, a vast range of grafts are available to the orthopaedic surgeon for augmenting connective tissue following rupture or tissue loss. While the biomechanical properties of these synthetic grafts become ever closer to the natural tissue, there have been no reports of their bio-tribological (i.e. bio-friction) characteristics. In this study, the bio-tribological performance of three clinically available synthetic tissue grafts, and natural tendon, was investigated. It was established that the natural tissue exhibits fluid-film lubrication characteristics and hence is highly efficient when sliding against opposing tissues. Conversely, all the synthetic tissues demonstrated boundary or mixed lubrication regimes, resulting in surface—surface contact, which will subsequently cause third body wear. The tribological performance of the synthetic tissue, however, appeared to be dependent on the macroscopic structure. This study indicates that there is a need for synthetic tissue designs to have improved frictional characteristics or to use a scaffold structure that encourages tissue in-growth. Such a development would optimize the bio-tribological properties of the synthetic tissue and thereby maximize longevity.

Recoil polarization measurements of the proton electromagnetic form factor ratio to Q2 = 8.5 GeV2

Among the most fundamental observables of nucleon structure, electromagnetic form factors are a crucial benchmark for modern calculations describing the strong interaction dynamics of the nucleon's quark constituents; indeed, recent proton data have attracted intense theoretical interest. In this Letter, we report new measurements of the proton electromagnetic form factor ratio using the recoil polarization method, at momentum transfers Q2=5.2, 6.7, and 8.5  GeV2. By extending the range of Q2 for which G(E)(p) is accurately determined by more than 50%, these measurements will provide significant constraints on models of nucleon structure in the nonperturbative regime.

Abstract 3626: Development of inhibitors of the fibroblast growth factor receptor (FGFR) kinase using a fragment based approach

Recent data in a number of tumour types has implicated Fibroblast Growth Factor (FGF) and Fibroblast Growth Factor receptor (FGFR) signalling as being key to the molecular pathology of cancer. FGFR is a receptor tyrosine kinase which activates the extracellular signal-regulated kinase / mitogen-activated protein kinase and the protein kinase B / Akt pathways which promote cell growth and survival. Amplification, over-expression or activating mutations of fibroblast growth factor receptors have been associated with bladder tumours, multiple myeloma, hormone-refractory prostate cancer and breast cancer.

Multiple lead series of FGFR inhibitors were developed using Astex's fragment based medicinal chemistry approach, Pyramid™, linked to high throughput X-ray Crystallography. We describe here the characterisation of some examples of these lead molecules. In particular we detail the pharmacological profile of a compound from one of these lead series that demonstrated activity against FGFR 1-4 with an IC50 <100nM in an isolated kinase assay. This compound inhibited FGFR1-4 kinase activity in BaF3 cell lines engineered to express the relevant kinase fusion proteins and proliferation and survival of a panel of FGFR-dependent human tumour cell lines derived from several different tissues. The cytotoxic activity was >10 fold lower in cell lines lacking FGFR expression. We demonstrate inhibition of FGFR 2 and 3 phosphorylation in gastric and multiple myeloma cell lines respectively with associated inhibition of downstream signalling pathways.

This lead molecule has an excellent pharmacokinetic profile and high oral bioavailibility in mice and rats. In xenograft models in mice where aberrant FGF signalling underlies tumour pathology, tumour growth inhibition is observed at doses of 100mg/kg /day orally for 21 days. This xenograft efficacy was observed in several models, with significantly lower activity in models where aberrant FGF signalling is not involved in tumour pathology. This suggests that the mechanism of action is consistent with FGFR inhibition. The pharmacological profile in these models is also distinct from other broader spectrum receptor tyrosine kinase inhibitors.

The pre-clinical data shown here suggests that such compounds warrant further investigation pre-clinically and may benefit patients whose disease is driven by FGFR activity.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3626.

Abstract 5443: Rational combinations with the HDAC inhibitor JNJ-26481585: Prostate cancer and taxane therapy

We have recently reported the identification and characterization of JNJ-26481585, as a “second generation” oral pan-HDAC inhibitor. The compound has shown potent in vitro activity against solid and hematological tumor cell lines and significant induction of apoptosis was observed, consistent with the potency of JNJ-26481585 for Class I HDACs. In dose response to JNJ-26481585, western blot analysis of A2780 cell extracts confirmed modulation of HDAC1-3 substrates and also HDAC6 substrates. Inhibition of HDAC6, the deacetylase for tubulin and Hsp90, results in depletion of oncogenic Hsp90 client proteins, decreased cell motility, and potentiation of therapeutics such as taxanes. We hypothesized that rational combinations with taxanes and JNJ-26481585 could result in enhanced tumor cell killing and describe our observations from the combination of JNJ-26481585 in PC3-M prostate tumors.

Combinations of JNJ-26481585 and taxanes were performed by co-administration or 24h separation of agents in A549, NCI-H460, NCI-H1373, NCI-H1703, NCI-H322 and NCI H-1650 lung cell lines; breast cell lines, MDA-MB-231, T47D, BT474 and MCF-7 cells; and prostate cell lines PC3M, DU-145, 22Rv1 and LnCap. We will present data on the outcome of these combinations, including additive and synergistic effects.

The in vitro data encouraged us to explore the effects of the compound in vivo and in prostate models where we already had excellent single agent activity for JNJ-26481585 in DU-145, PC-3 and the PC-3M orthotopic model (significant T/C values in each model and at doses substantially below MTD). In PC3-M xenograft models, the combination of 1.25, 5 or 10mpk JNJ-26481585 (Q2D) and taxotere (Q7D), was more effective than either agent alone and resulted in dose dependent tumor regression and substantial extension of time to relapse. We then selected the more challenging PC-3M orthotopic mouse model to further define the contribution to efficacy from the excellent tissue distribution of our agent. Comparing 5mpk taxotere (Q7D), with 1 or 3mpk of JNJ-26481585 (QD) or the combination of agents, the activity of taxotere alone was surpassed by either dose of HDAC inhibitor alone and substantial tumor growth delay was observed from the combination of 3mpk JNJ-26481585 and taxotere; activity greater than predicted from the in vitro experiments.

Finally, although HDAC6 inhibition could directly explain potentiation of taxotere by JNJ-26481585 in vitro, we believe the substantial effects in vivo may be due to the anti-angiogenic effect observed for our agent. We present also our data showing anti-angiogenic effects of JNJ-26481585 in PC3-M tumors, consistent with this hypothesis. Our data support the further use of more complex models, reflective of human disease in preclinical assessment and also support further exploration of this agent in rational combinations with SOC agents. JNJ-26481585 is currently in Phase I clinical trials.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5443.

Abstract 752: In vivo pharmaceutical targets screening using lentiviral inducible-knockdown shRNA system

Background and Aims: Small interfering RNAs (shRNAs) are able to suppress gene expression through the endogenous cellular process of RNA interference pathway. Given the ability to knock-down essentially any gene, shRNAs have been used in many studies to screen for therapeutic targets in various pathological conditions. However, most of these studies have been carried out in vitro and the results cannot always be translated into an in vivo environment. In this project, we aimed to develop an efficient in vivo cancer target validation method using a lentiviral inducible-knockdown shRNA. To verify our approach, we used an essential cell-cycle protein polo-like kinase 1 (PLK1) as a proof of concept target.

Methods: TRIPZ inducible shRNAmir construct (Open Biosystems) carrying shRNA against PLK1 was transfected into the colon carcinoma cell line SW620 using lentiviral transduction. PLK1 gene knock-down following induction with doxycycline was quantified by real-time PCR. Inducible shRNAmir expression (detected by turboRFP) was monitored by fluorescence microscopy and quantified using Flow-cytometry or a fluorescence microplate reader.

Nude mouse xenografts were established by subcutaneous injection of 5×106 PLK1 shRNA transfected SW620 cells into the left flank of female nude mice. Doxycycline treatment (80mg/kilogram daily via oral gavage) was initiated when the mean tumour volume reached 500mm3. Mice were sacrificed 3 weeks following treatment and tumours were collected. PLK1 gene expression was assessed by RT-PCR and protein levels investigated using immunohistochemistry. Assessment of angiogenesis (micro-vessel density) was carried out using CD34 staining.

Results:

Following doxycycline induction in vitro, PLK1 inducible-knockdown SW620 cells showed dose and time-dependent PLK1 down-regulation, which was consistent with shRNAmir expression as marked by turboRFP. Flow-cytometry analysis showed about 95% of cells expressed the shRNAmir, 72 hours after induction.

In the in vivo model, the doxycycline-treated group showed significantly lower PLK1 gene expression compared with untreated control (60% reduction, p<0.003). The doxycycline-treated group also showed significantly lower PLK1 protein expression compared with the untreated control (p<0.001).

There was a decline in tumour growth rate in the treated group compared with the control group, which confirmed that knock-down of PLK1 slowed down tumour growth.

We also observed that, within the tumours from the doxycycline-treated group, there appeared to be reduced PLK1 expression in areas adjacent to the blood vessels compared with other areas of the tumour.

Conclusion: The results support the anti-tumour effects of PLK1 down-regulation and confirm an efficient methodology for cancer target screening using a lentiviral inducible-knockdown shRNA system.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 752.

Abstract 5441: Preclinical assessment of the HDAC inhibitor JNJ-26481585: potent in vivo activity across a broad spectrum of human tumor xenografts

JNJ-26481585 is a promising “second generation” oral pan-HDAC inhibitor. Recently, we have published data describing the identification and characterization of the molecule as a potent inhibitor of HDAC1 with a favorable pharmacodynamic profile. Subsequent analysis has shown that the compound has pan-HDAC inhibitory activity and demonstrates effective inhibition of tumor cell growth across a broad spectrum of solid and hematological tumor cell lines. Recent data has also shown that in vivo JNJ-26481585 alone, or in combination with bortezomib, is an effective agent in myeloma. Herein we describe the activity of JNJ-26481585 against a broad range of preclinical solid tumor xenograft models, at doses substantially below MTD and with different schedules of administration in order to address the clinical utility of this agent.

Significant growth inhibition was achieved when dosing JNJ-26481585 at MTD with T/C in tumors of; A2780 ovarian tumor xenograft (3%), ras-mutant colon (HCT-116), (7%), MDA-MB-231 breast (38%), DU-145 prostate (11%) and lung H460, A549 and ras mutant NCI-H1373 (29%, 15% and 32% respectively). In the A2780 model, activity of JNJ-26481585 was superior to that of five other HDAC inhibitors tested. This class leading activity was observed at MTD and optimal route of administration of all compounds and importantly, we also observed significant activity of JNJ-26481585 at concentrations as low as 12.5% of MTD (T/C = 35%). Both class leading activity and significant tumor growth inhibition at concentrations substantially below MTD was also observed in A549, DU145 and HCT116 tumor xenografts. Furthermore, in HCT116, in line with taxotere in prostate models, JNJ-26481585 was shown to be more effective than the SOC, 5-FU. The HCT116 model was used further to address the potential of the compound for clinical utility by exploring alternative dosing schedules to that of QD IP dosing. 3 days on/4 days off, 1 week on/ 1 week off, Q2D and Q7D were all investigated alongside QD dosing and observed to inhibit tumor growth in all cases; Q7D was the only alternative schedule not to achieve efficacy equivalent to that with QD dosing.

Finally, data indicating greater activity or equivalence with the SOC suggested that JNJ-26481585 could be used in those indications, thus potency was investigated in drug resistant patient material. In both taxol resistant NSCLC and doxorubicin resistant breast cancer cultures, JNJ-26481585 dramatically inhibited proliferation. We conclude that in preclinical models, JNJ-26481585 was effective at reducing the tumor size to the greatest extent of all HDAC agents studied. Potent antitumoral activity was also observed at doses substantially below MTD and from alternative dosing schedules, suggesting that this could be a promising agent for clinical development in such indications. JNJ-26481585 is currently in Phase I clinical trials.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5441.

Abstract A10: Upregulation of ADAM17 protease and HER ligands through a PKB negative feedback loop mediates acquired resistance to Trastuzumab in HER2 overexpressed breast cancer

The decision to treat breast cancer patients with Trastuzumab is based on HER2 receptor over-expression or gene amplification. However, even in this selective group of patients, the response rate remains poor and unpredictable. Furthermore, all responders eventually become resistant if Trastuzumab is given as monotherapy. It is still poorly understood how Trastuzumab exerts its mechanism of action and how the acquired resistance to this drug occurs. We have found the molecular mechanisms whereby Trastuzumab fails to abolish HER2 phosphorylation despite being an anti-HER2 monoclonal antibody and have resolved the inconsistencies in the literature regarding the effect of Trastuzumab on HER2 phosphorylation. Trastuzumab did not decrease HER2 phosphorylation in these cells despite the effect on HER2 receptor downregulation. HER2 phosphorylation was maintained by activation of EGFR, HER3 and HER4 via their dimerisation with HER2. The activation of EGFR, HER3 and HER4 was due to an upregulation of HER ligands including heregulin and betacellulin. The upregulation of HER ligands was mediated by ADAM17 through a PKB negative feedback loop. The feedback loop was activated because of the inhibition of PKB by Trastuzumab treatment since upregulation of HER ligands and ADAM17 also occurred when PKB phosphorylation was inhibited by a PKB inhibitor (Akt inhibitor VIII, Akti-1/2). However, the combination treatment of Trastuzumab with a panHER inhibitor JNJ-26483327 was able to abrogate the feedback loop and it was synergistic in tumour inhibition in a BT474 xenograft model. Our data provides evidence that Trastuzumab resistance can be mediated by activation of HER family ligands as a direct consequence of inhibition of HER2 and PKB signalling. This offers treatment opportunities for overcoming resistance in these patients, including approaches to target all HER receptors in combination with Trastuzumab treatment. Future research should utilize a systems biology approach to identify other feedback loops that may be involved in the acquired resistance to Trastuzumab treatment in HER2 positive breast cancer.

Citation Information: Clin Cancer Res 2010;16(7 Suppl):A10

Preclinical anti-myeloma activity of the novel HDAC-inhibitor JNJ-26481585

Pharmacological inhibitors of histone deacetylases (HDACs) are currently being developed and tested as anti-cancer agents and may be useful to enhance the therapeutic efficiency of established anti-myeloma treatments. This study preclinically evaluated the effects of the 'second generation' pan-HDAC inhibitor JNJ-26481585 on human multiple myeloma (MM) cells from established cell lines and primary MM samples (n=42). Molecular responses in both groups of MM cells included histone acetylation, a shift in Bcl2-family members towards proapoptotic bias, attenuation of growth and survival pathway activity and Hsp72 induction. Mcl-1 depletion and Hsp72 induction were the most reliable features observed in JNJ-26481585-treated primary MM samples. The drug alone effectively induced myeloma cell death at low nanomolar concentrations. In vitro combination of JNJ-26481585 with anti-myeloma therapeutic agents generally resulted In effects close to additivity. In view of the favourable activity of this novel HDAC-inhibitor towards primary myeloma cells further evaluation in a clinical setting is warranted.

Prehospital advanced airway management by ambulance technicians and paramedics: is clinical practice sufficient to maintain skills?

INTRODUCTION

Ambulance paramedics are now trained routinely in advanced airway skills, including tracheal intubation. Initial training in this skill requires the insertion of 25 tracheal tubes, and further ongoing training is attained through clinical practice and manikin-based practice. In contrast, training standards for hospital-based practitioners are considerably greater, requiring approximately 200 tracheal intubations before practice is unsupervised. With debate growing regarding the efficacy of paramedic intubation, there is a need to assess current paramedic airway practice in order to review whether initial training and maintenance of skills provide an acceptable level of competence with which to practice advanced airway skills.

METHODS

All ambulance patient report forms (anonymised) for the period 1 January 2007 to 31 December 2007 were reviewed, and data relating to airway management were collected. Paramedic and technician identification codes were used to determine the number of airway procedures undertaken on an individual basis.

RESULTS

Of the 269 paramedics, 128 (47.6%) had undertaken no intubation and 204 (75.8%) had undertaken one or less intubation in the 12-month study period. The median number of intubations per paramedic during the 12-month period was 1.0 (range 0-11). A total of 76 laryngeal mask insertion attempts were recorded by 41 technicians and 30 paramedics. The median number of laryngeal mask insertions per paramedic/technician during the 12-month period was 0 (range 0-2). A survey of ongoing continuing professional development across all ambulance trusts demonstrated no provision for adequate training to compensate for the lack of clinical exposure to advanced airway skills.

CONCLUSION

Paramedics use advanced airway skills infrequently. Continuing professional development programmes within ambulance trusts do not provide the necessary additional practice to maintain tracheal intubation skills at an acceptable level. Advanced airway management delivered by ambulance crews is likely to be inadequate with such infrequent exposure to the skill.

Abstract B111: Differential expression of c-Met/HGF axis and epithelial-mesenchymal transition (EMT)-related gene markers between primary colorectal carcinomas and liver metastases in primary tissue, isolated cell types and in vivo

Introduction: EMT is frequently activated in a subset of tumor cells during disease progression. EMT is described as downregulation of E-cadherin with a corresponding upregulation of mesenchymal markers such as Vimentin. EMT is linked to carcinoma progression stemming from increased tumor cell motility, growth, survival, and invasion. The c-Met receptor and MACC1 (metastasis-associated in colon cancer-1) are often upregulated in CRC metastases, have been associated with increased metastasis, and represent potential drug targets. Here we assessed the expression of genes associated with EMT in human CRCs and liver metastases (LMs), in epithelial cells isolated from primary tissues and in mouse passaged primary tumor xenografts.

Methods: Human primary CRC (n = 11) and LM (n = 21) samples, along with matched normal tissues, were obtained under full ethical approval from the Queen's Medical Centre, Nottingham, UK. Real-time quantitative PCR was used to determine expression levels of EMT-related markers (growth factors, transcriptional repressors, mesenchymal markers) relative to the housekeeping gene hypoxanthine-guanine phosphoribosyltransferase, from (i) primary tissues, (ii) epithelial cells and fibroblasts isolated from disaggregated primary tissues using cell type-specific antibodies bound to magnetic beads, (iii) primary tumor tissues subcutaneously passaged in nude mice. A student's t-test was used for statistical analyses.

Results: MACC1 and c-Met were significantly upregulated, whereas E-cadherin was significantly downregulated, in CRC and LM primary tissues compared to normal colonic mucosa, indicating that EMT had occurred. In LMs, hepatocyte growth factor (HGF), Snail, Slug, Twist, Vimentin, TGFβ1, and matrix metalloproteinase 9 were also significantly upregulated (P <0.05), whereas expression of Zeb1, s100a4, and MMP2 were not altered. Gene expression profiles from isolated epithelial cells and fibroblasts showed that hgf, vimentin, and TGFβ1 were predominantly expressed by mesenchymal cells, whereas c-met, e-cadherin, and snail expression were predominantly epithelial. In xenograft tumor tissues, hgf and vimentin expression was lost within the first passage, whereas e-cadherin and c-met expression was maintained, indicating that human stroma was rapidly replaced.

Conclusions: Phenotypic markers consistent with EMT were significantly increased in LMs compared to CRCs, and Snail, Twist, Vimentin, TGFβ1, and MMP9 provide the best markers for LM. In CRCs and LMs, paracrine signalling of HGF (mesenchymal) to the c-Met receptor (epithelial) is likely to occur, and this signalling pathway appears to be lost during growth of the primary tumor in nude mice. This has important implications in therapy studies targeting the HGF-MACC1-cMet axis.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B111.

The role of ghrelin and ghrelin-receptor gene variants and promoter activity in type 2 diabetes

BACKGROUND

Ghrelin and its receptor play an important role in glucose metabolism and energy homeostasis, and therefore they are functional candidates for genes carrying susceptibility alleles for type 2 diabetes.

METHODS

We assessed common genetic variation of the ghrelin (GHRL; five single nucleotide polymorphisms (SNP)) and the ghrelin-receptor (GHSR) genes (four SNPs) in 610 Caucasian patients with type 2 diabetes and 820 controls. In addition, promoter reporter assays were conducted to model the regulatory regions of both genes.

RESULTS

Neither GHRL nor GHSR gene SNPs were associated with type 2 diabetes. One of the ghrelin haplotypes showed a marginal protective role in type 2 diabetes. We observed profound differences in the regulation of the GHRL gene according to promoter sequence variants. There are three different GHRL promoter haplotypes represented in the studied cohort causing up to 45% difference in the level of gene expression, while the promoter region of GHSR gene is primarily represented by a single haplotype.

CONCLUSION

The GHRL and GHSR gene variants are not associated with type 2 diabetes, although GHRL promoter variants have significantly different activities.