Traumatic injury elicits JNK-mediated human astrocyte retraction in vitro

Brain injury causes dysfunction of the blood-brain barrier (BBB). The BBB is comprised of perivascular astrocytes whose end-feet ensheath brain microvascular endothelial cells. We investigated trauma-induced morphological changes of human astrocytes (HA) and human cerebral microvascular endothelial cells (hCMEC/D3) in vitro, including the potential role of mitogen-activated protein kinase (MAPK) signal-transduction pathways. HA or hCMEC/D3 were grown on flexible culture membranes and subjected to single traumatic injury normalized to 20%, 30% or 55% membrane deformation. Cells were assayed for morphological changes (i.e. retraction) and MAPK phosphorylation and/or expression (c-Jun NH2-terminal kinase (JNK)1/2, extracellular signal-regulated kinase (ERK)1/2, and p38). HA retraction was rapidly elicited with a single traumatic injury (55% membrane deformation; p<0.01). Morphological recovery of HA was observed within 2h (p<0.05). Traumatic injuries increased phospho-JNK1/2 (p<0.05) in HA, indicating MAPK activation. Pre-treatment of HA with structurally distinct JNK inhibitors (25μM), either SP600125 or SU3327, reduced JNK phosphorylation (p<0.05) and trauma-induced HA retraction (P<0.05). In contrast to HA, traumatic injury failed to induce either morphological changes or MAPK activation in hCMEC/D3. In summary, traumatic injury induces JNK-mediated HA retraction in vitro, while sparing morphological changes in cerebral microvascular endothelial cells. Astrocyte retraction from microvascular endothelial cells in vivo may occur after brain trauma, resulting in cellular uncoupling and BBB dysfunction. JNK may represent a potential therapeutic target for traumatic brain injuries.

A phase I multi-institutional study of systemic sorafenib in conjunction with regional melphalan for in-transit melanoma of the extremity

BACKGROUND

Isolated limb infusion with melphalan (ILI-M) corrected for ideal body weight (IBW) is a well-tolerated treatment for patients with in-transit extremity melanoma with an approximate 29 % complete response (CR) rate. Sorafenib, a multi-kinase inhibitor, has been shown to augment tumor response to chemotherapy in preclinical studies.

METHODS

A multi-institutional, dose-escalation, phase I study was performed to evaluate the safety and antitumor activity of sorafenib in combination with ILI-M. Patients with AJCC stage IIIB/IIIC/IV melanoma were treated with sorafenib starting at 400 mg daily for 7 days before and 7 days after ILI-M corrected for IBW. Toxicity, drug pharmacokinetics, and tumor protein expression changes were measured and correlated with clinical response at 3 months.

RESULTS

A total of 20 patients were enrolled at two institutions. The maximum tolerated dose (MTD) of sorafenib in combination with ILI-M was 400 mg. Four dose-limiting toxicities occurred, including soft tissue ulcerations and compartment syndrome. There were three CRs (15 %) and four partial responses (20 %). Of patients with the Braf mutation, 83 % (n = 6) progressed compared with only 33 % without (n = 12). Short-term sorafenib treatment did alter protein expression as measured with reverse phase protein array (RPPA) analysis, but did not inhibit protein expression in the MAP kinase pathway. Sorafenib did not alter melphalan pharmacokinetics.

CONCLUSION

This trial defined the MTD of systemically administered sorafenib in combination with ILI-M. Although some responses were seen, the addition of sorafenib to ILI-M did not appear to augment the effects of melphalan but did increase regional toxicity.

A phase I study of systemic sorafenib in combination with isolated limb infusion with melphalan (ILI-M) in patients (pts) with locally advanced in-transit melanoma

9065

Background: Sorafenib is a multi-kinase inhibitor that may also enhance the cytotoxicity of concurrently administered chemotherapy. In a preclinical model of regionally advanced melanoma, the combination of systemic Sorafenib and regional melphalan led to augmented tumor responses. Methods: A Phase I multicenter study was performed to evaluate the safety and pharmacokinetics (PK) of systemic Sorafenib in combination with ILI-M in patients with measurable in-transit melanoma of the extremity. Sorafenib dose escalation cohorts consisted of 200mg, 300mg, and 400mg administered systemically twice daily for one week prior and one week after a standard dose ILI-M corrected for ideal body weight. Tumor biopsies pre-therapy and pre-ILI were obtained to assess molecular changes associated with Sorafenib pretreatment. Response was defined at 3 months using RECIST. Results: Nine pts with high disease burden, including 7 previous ILI-M alone failures, have been treated; 3 in the first cohort and 6 in the second cohort. There were no grade 5 toxicities. Four patients had CTCAE Grade 4 toxicities including neutropenia (2), CPK elevation (1), and skin ulceration (1). In the remaining 5 patients, there were no >grade 3 toxicities. The maximally tolerated dose (MTD) has not yet been defined. Initial in field response determination in 6 of the 9 patients out at least 3 months includes 2 partial responses and 4 disease progressions. Conclusions: Systemic Sorafenib administered pre and post ILI-M is a well tolerated, novel targeted therapy approach to regionally advanced melanoma. An additional 10 patients will be enrolled to define the MTD. Correlation of response with drug PK, Sorafenib downregulation of pErk and Mcl1, and a melphalan resistance signature is in progress.

No significant financial relationships to disclose.

Global analysis of gene expression patterns in developing mouse neocortex using serial analysis of gene expression

Molecular inventories of the developing mouse neocortex before and after birth were generated using the global gene expression profiling tool serial analysis of gene expression (SAGE). Libraries were generated from embryonic day 15 and postnatal day 1 mouse neocortex and more than 40,000 tags were collected (20,211 and 22,001 tags, representing 11,706 and 12,402 transcripts, respectively). Comparison of the two libraries resulted in the identification of 321 transcripts that were differentially expressed (P < 0.05). Differential expression was independently verified for selected genes by Northern blotting, and in situ hybridization revealed spatial expression patterns in the neocortex. Differentially expressed transcripts included genes known to be important in neocortical development (e.g., brain factor 1, neuroD2, and Id2), genes not previously associated with neocortical development (such as brahma-related gene 1, receptor for activated C-kinase I, hypermethylated in cancer 2, and Evi9), and genes of unknown identity or function.

Place- and time-dependent expression of mouse sFRP-1 during development of the cerebral neocortex

Wnts are a family of secreted proteins involved in multiple developmental mechanisms during nervous system development, including cell proliferation, cell migration, axon guidance and specification of cell positional information. We report here the expression of sFRP-1 mRNA, encoding a putative inhibitor of Wnt, in the developing mouse neocortex during the entire period when neurons for the neocortex are born. We show that sFRP-1 mRNA expression is spatially restricted to the proliferative zones during the period, when neurons are known to be generated in large numbers for the enlarging cortical plate.

Genetic basis for diabetes resistance in NOD/Wehi mice

The basis for diabetes resistance in low diabetes incidence NOD/Wehi mice was examined in a breeding study. NOD/Wehi mice were crossed with high diabetes incidence NOD/Lt mice producing F1 hybrid mice which expressed a low incidence of diabetes. To distinguish between genetic and environmental causes for diabetes resistance, these F1 mice were backcrossed to NOD/Lt mice resulting in BC1 hybrid mice which expressed an intermediate incidence of diabetes. Similar results were obtained by examining the severity of insulitis in the hybrid mice. As both the incidence of diabetes and severity of insulitis in the hybrid mice were consistent with a single dominant gene mediating diabetes resistance, an attempt to localize this gene was made. Although over 140 loci which display polymorphism amongst inbred strains were typed in both parental lines, only a single locus, D8Mit9, was found to differ. As heterozygotes at D8Mit9 were not over represented amongst 45 diabetic BC1 hybrid mice examined, it was concluded that a resistance gene was not linked to this locus.

An investigation of the pathophysiology of ischaemic neuropathy

This study assesses the changes in the microvasculature of peripheral nerves in acute large vessel ischaemic neuropathy. An animal model of large vessel ligation, producing an ischaemic neuropathy was used: the presence and extent of the neuropathy was documented by clinical examination and nerve conduction studies. The nerve microcirculation, the "vasa nervorum" was examined using casting materials, methyl methacrylate and silicone rubber, which were in turn examined by light microscopy and scanning electron microscopy. In all, ten animals were used, all of whom showed clinical evidence of an ischaemic neuropathy 1 week post-ligation. This ischaemic neuropathy was confirmed by nerve conduction studies. Corrosion casts were produced in five of the ten animals. Examination of these casts showed that all five had an area of underfilling of the microcirculation in the region of the proximal tibial nerve with good filling of vessels proximal and distal to this, indicating that in generalised hypoperfusion states such as large vessel ligation, the area of poorest perfusion (and thus maximal damage) is not the distal vascular field, but a probable "watershed zone" between two adjacent nutrient vessels to the nerve.