A Rho kinase (ROCK) inhibitor, fasudil, prevents matrix metalloproteinase-9-related hemorrhagic transformation in mice treated with tissue plasminogen activator

Thrombolysis with tissue plasminogen activator (tPA) is the only FDA-approved therapy for acute ischemic stroke. However, hemorrhagic transformation, neurotoxicity, and a short treatment time window comprise major limitations for thrombolytic therapy. The purpose of the present study was to investigate whether fasudil, a Rho kinase (ROCK) inhibitor, would prevent tPA-associated hemorrhagic transformation and extend the reperfusion window in an experimental stroke model in mice. Mice subjected to 6-h middle cerebral artery occlusion were treated with delayed tPA alone, with combined tPA plus fasudil, or with a vehicle. We used histological and neurobehavioral measures to assess the effects of the treatment at 18 h and 7 days after the reperfusion. To investigate the mechanism of fasudil's beneficial effects further, we also performed an in vitro study with tPA and fasudil in human brain microvascular endothelial cells. Combination therapy with tPA plus fasudil prevented the development of hemorrhagic transformation, but did not reduce the infarct volumes. These changes significantly reduced mortality and increased locomotor activity at 7 days after the reperfusion. Furthermore, the administration of both drugs prevented injury to the human brain endothelial cells via the reduction of matrix metalloproteinase-9 (MMP-9) activity. These findings indicate that fasudil prevents the hemorrhagic transformation induced by focal cerebral ischemia in mice treated with tPA, at least in part, by inhibiting the increased activity of MMP-9 in endothelial cells.

A broad-spectrum matrix metalloproteinase inhibitor prevents hemorrhagic complications induced by tissue plasminogen activator in mice

Delayed activation of tissue plasminogen activator (tPA) can lead to the disruption of the blood-brain barrier (BBB), resulting in hemorrhagic complications. In the present study, we focused on tight junction proteins (TJPs), occludin, zona occludens (ZO)-1, and claudin-5, which are important structural components of the BBB, and investigated whether inhibition of matrix metalloproteinases (MMPs) provides a protective effect against hemorrhagic complications induced by tPA. We subjected mice to 6-h filamental middle cerebral artery occlusion (MCAO) with vehicle, delayed tPA alone, or combined tPA (10 mg/kg, i.v.) plus GM6001 (100 mg/kg, i.p.), a broad-spectrum MMP inhibitor. We evaluated brain hemoglobin and the expression of MMP-9 and TJPs by immunoblotting. GM6001 significantly reduced tPA-elevated brain hemoglobin, MMP-9, and inhibited the degradation of occludin and ZO-1 induced by tPA, but not claudin-5. Treatment with GM6001 also significantly prevented the decrease in the survival rate and the reduction in locomotor activity caused by tPA at 7 days after ischemia/reperfusion. Furthermore, GM6001 treatment also significantly prevented cell damage, determined by release of lactase dehydrogenase (LDH) activity, and the decrease in transendothelial electrical resistance (TEER) induced by tPA. These findings indicate that GM6001 prevented the hemorrhagic complications and improved the behavioral abnormalities induced by tPA, partly via protection of TJPs. This suggests that GM6001 may be a useful candidate for combination therapy against the hemorrhagic complications induced by tPA.

Forebrain specific heparin-binding epidermal growth factor-like growth factor knockout mice show exacerbated ischemia and reperfusion injury

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a hypoxia-inducible neuroprotective protein that also stimulates proliferation of neuronal precursor cells. In this study, we investigated the possible role of HB-EGF in ischemia and reperfusion injury by measuring the changes in its mRNA expression following focal cerebral ischemia. We also examined neural damage after a middle cerebral artery occlusion (MCAO) and reperfusion in ventral forebrain specific HB-EGF knockout (KO) mice. The levels of HB-EGF mRNA in the cerebral cortex of wild-type (WT) mice were significantly increased 3-24 h after MCAO and reperfusion. Cerebral infraction in HB-EGF KO mice was aggravated at 1 day and 6 days after MCAO and reperfusion compared with WT mice. The number of terminal deoxynucleotidyl transferase (TdT)-mediated dNTP nick end labeling (TUNEL) and an oxidative stress marker, 8-hydroxy-2'-deoxyguanosine (8-OHdG) positive cells, were higher in HB-EGF KO mice than in WT mice. On the other hand, fewer bromodeoxyuridine (BrdU) positive cells were found in the subventricular zone in HB-EGF KO mice compared with WT mice. These results indicate that HB-EGF may play a pivotal role in ischemia and reperfusion injury and that endogenously synthesized HB-EGF is necessary for both the neuroprotective effect and for regulation of cell proliferation in the subventricular zone.

Modulation in concentrative nucleoside transporters-mediated intestinal absorption of mizoribine, an immunosuppressive agent, in lipopolysaccharide-treated rats

The characteristics of intestinal absorption of mizoribine and cephalexin, that are mediated by concentrative nucleoside transporters (CNTs) and PEPT1, respectively, was examined in lipopolysaccharide (LPS)-treated rats. LPS treatment is known to modify the expression of some transporters and induce cholestasis. At 24 h after the LPS treatment, averaged concentrations of IL-6 and total bile acids in plasma were 15-fold and 2-fold that in untreated control rats, respectively, and bile flow rate decreased by 40% of control, indicating the induction of inflammatory and cholestatic states. The oral bioavailability, estimated by urinary excretion percentage of unchanged form, of mizoribine in LPS-treated rats was 1.5-fold higher than that in control rats, whereas the bioavailability of cephalexin remained unchanged. When mizoribine and cephalexin were administered into in-situ jejunum loops, there were no differences in the absorption rates between control and LPS-treated rats. These results indicated that the functional expression of CNT1, CNT2, and PEPT1 were not modulated by LPS treatment. When mizoribine (a CNT1/CNT2 substrate) and gemcitabin (a CNT1 substrate) were administered as a solution dissolved in bile into the intestinal loop, their absorption rates decreased significantly. In contrast, the absorption rate of ribavirin (a CNT2 substrate) remained unchanged. In conclusion, LPS treatment exerted no significant effect on the expression of CNT1 and CNT2 in the intestine. Bile was found to suppress the CNT1-mediated intestinal absorption of mizoribine and gemcitabin. The increased oral bioavailability of mizoribine in LPS-treated rats could be ascribed to the less amount of bile or bile acids in the intestine under cholestatic state of rats.

The final report of post-marketing surveillance for cetuximab in colorectal cancer in Japan

590

Background: Cetuximab (ERBITUX) was approved in Jul 2008 in Japan with indication for EGFR-positive and unresectable metastatic or refractory colorectal cancer. Post-marketing surveillance is required by Japanese Health Authority to collect, obtain, verify or validate information on the safety, efficacy and quality of medicines. We conducted this surveillance in all patients treated with cetuximab to access in practical use since clinical data on Japanese patients are limited.

Methods: The target number of patients was 1,800. Following adverse drug reactions were investigated: infusion reaction, skin disorders, interstitial lung diseases, electrolyte abnormalities (including hypomagnesemia), heart toxicities, gastrointestinal disorders, thrombosis/embolism, delayed wound healing, and eye disorders.

Results: Between Sep 2008 until Jan 2010, 2,126 pts registered, 2,006 pts were evaluable for safety (safety population), 1,687 pts for efficacy (efficacy population). Of the 2,006 pts, 1,975 pts (98.5%) were EGFR-positive. Patients characteristics: male/female; 1,234/772 (61.5%/38.5%), median age; 64 (range 18-87), site of primary tumor; colon/rectal/others (multiple selection); 1,235/775/3 (61.6%/38.6%/0.2%), PS0/PS1; 1,370/630 (68.3%/31.4%), combination chemotherapy; cetuximab monotherapy/CPT-11/FOLFIRI: 460/1,255/256 (22.9%/62.56%/12.8%). Of the 2,006 pts, 133 pts (6.6%) and 1,869 pts (93.2%) were treated in second-line and in third-line or later treatment, respectively. The adverse drug reactions incidence was 89.9%. Incidence of skin disorders, gastrointestinal disorders, electrolyte abnormality including hypomagnesaemia, and infusion reaction were 83.7%, 23.1%, 11.5%, and 5.7%, respectively. Efficacy result: Of the 1,687 pts, 658 pts (39.0%) were evaluated to be effective. Of the 658 pts, 614 pts (93.3%) experienced skin adverse reactions.

Conclusions: This post-marketing surveillance confirms the safety and efficacy of cetuximab in the Japanese population treated in clinical practice. The outcome of this surveillance with Japanese 2,006 pts would be useful for clinical use of cetuximab.

[Table: see text]

Clinicopathological features in metastatic colorectal cancer patients with KRAS wild type compared with codon 12 and codon 13 mutant: Results from a multicenter, cross-sectional study by the Japan study group of KRAS mutation in colorectal cancer

407

Background: The KRAS mutation mainly located in the codon 12 and 13 indicates unresponsiveness of patients with metastatic colorectal cancer (CRC) to anti-epidermal growth factor receptor (EGFR) antibodies. Many studies have reported that approximately 30%-40% of CRC patients have KRAS mutations. However, the clinicopathological features of KRAS mutant CRC have not been fully clarified, especially in Asian populations. This study aimed to clarify the clinicopathological features of KRAS mutant CRC in comparison with KRAS wild type in large-scale Japanese population.

Methods: The key eligibility criteria included histologically confirmed colorectal adenocarcinoma with adequate tumor samples. Formalin-fixed paraffin-embedded tumor blocks or thinly sliced tumor sections from 389 centers were sent to commercial laboratories. Almost all KRAS point mutations in the codon 12 and 13 were investigated by direct sequencing (96%). The logistic regression analysis was used to estimate the odds ratios (ORs) and compute 95% confidential intervals (CIs).

Results: Of 5,887 registered tumor samples between Oct. 2009 and Mar. 2010, the KRAS testing were performed for 5,790 samples. As of the cut-off date, Sep. 2010, we have successfully determined the KRAS mutational status of 5,732 samples (99%).The median age was 65 years old, and 61% were male. The primary tumor site was right colon, left colon, and rectum in 30, 38, and 32% patients, respectively. The frequency of KRAS mutation was 37.6% (2,155/5,732), of which the 80% (1,714/2,155) mutations were located in codon 12. On logistic regression analysis, female gender (OR=1.212, 95% CI=1.083-1.356), older age > 50 years (OR=1.312, CI=1.056-1.628) and right colon (versus left: OR=2.177, CI=1.905- 2.489; versus rectum: OR=1.500, CI=1.308-1.720) were independent risk factors of KRAS mutant CRC. Clinicopathological features were similar between codon 12 and 13 mutant CRC.

Conclusions: This study disclosed that KRAS mutant CRC was different from KRAS wild type CRC in terms of clinicopathological features.

No significant financial relationships to disclose.

Synthesis and determination of configuration of natural 25-hydroxyvitamin D(3) 26,23-lactone

The four stereoisomers of 25-hydroxyvitamin D(3) 26,23-lactone were synthesized by a stereoselective lactonization method. Natural 25-hydroxyvitamin D(3) 26,23-lactone was produced from 25-hydroxy-[3alpha-(3)H]vitamin D(3) by in vitro incubation of kidney homogenate prepared from vitamin D-supplemented chickens or was isolated from the serum of rats given 1,25-dihydroxyvitamin D(3) and 25-hydroxy-[3alpha-(3)H]vitamin D(3). The four synthetic isomers and the naturally produced 25-hydroxyvitamin D(3) 26,23-lactone were subjected to high-performance liquid chromatography in a system capable of separating the four isomers. The natural lactone comigrated with synthetic (23S,25R)-25-hydroxyvitamin D(3) 26,23-lactone, establishing it as the natural vitamin D(3) metabolite.

Growth pattern in the muscular layer reflects the biological behaviour of colorectal cancer

OBJECTIVE

To determine the clinical value of evaluating the cancer morphology in muscularis propria (MP) for colorectal cancer (CRC) patients.

METHOD

A total of 994 patients with advanced CRC were reviewed in terms of two distinctive growth patterns in the MP: (i) horizontal spread between the circular and longitudinal muscle layers (H-spread) and (ii) 'streaming' spread between the muscle bundles of the circular muscle layer (S-spread).

RESULTS

The incidence of H-spread (n = 153) and S-spread (n = 150) showed a positive correlation with tumour-node-metastasis (TNM) stage and both exerted a negative impact on postoperative survival. Adverse morphology in the MP (H-spread and/or S-spread) was consistent with a high grade of vascular invasion and budding in the extramural layer, as also with unfavourable fibrotic stromas in the reactive fibrous zone; the 5-year survival rate in patients with such features was 64.2%, which was lower than that in those without (86.5%, P < 0.0001). Multivariate analysis demonstrated that adverse morphology was an independent prognostic determinant, along with T- and N -stage. As the mode of H-spread, perineural invasion in the myenteric plexus was found to be predominant over lymphatic spread on the basis of S100 and CD34 immunostaining, but neural cell adhesion molecule expression, whether on cancer cells or on neural cells, was not significant for this growth pattern.

CONCLUSION

A particular group of CRCs ingeniously utilizes the thin space between muscle fascicles for development in the MP. Although the biological mechanism remains unknown, this distinctive growth pattern could be a useful indicator to identify CRC patients at high risk of recurrence.

Regolith Migration and Sorting on Asteroid Itokawa

High-resolution images of the surface of asteroid Itokawa from the Hayabusa mission reveal it to be covered with unconsolidated millimeter-sized and larger gravels. Locations and morphologic characteristics of this gravel indicate that Itokawa has experienced considerable vibrations, which have triggered global-scale granular processes in its dry, vacuum, microgravity environment. These processes likely include granular convection, landslide-like granular migrations, and particle sorting, resulting in the segregation of the fine gravels into areas of potential lows. Granular processes become major resurfacing processes because of Itokawa's small size, implying that they can occur on other small asteroids should those have regolith.

Developing space weathering on the asteroid 25143 Itokawa

Puzzlingly, the parent bodies of ordinary chondrites (the most abundant type of meteorites) do not seem to be abundant among asteroids. One possible explanation is that surfaces of the parent bodies become optically altered, to become the S-type asteroids which are abundant in the main asteroid belt. The process is called 'space weathering'-it makes the visible and near-infrared reflectance spectrum of a body darker and redder. A recent survey of small, near-Earth asteroids suggests that the surfaces of small S asteroids may have developing stages of space weathering. Here we report that a dark region on a small (550-metre) asteroid-25143 Itokawa-is significantly more space-weathered than a nearby bright region. Spectra of both regions are consistent with those of LL5-6 chondrites after continuum removal. A simple calculation suggests that the dark area has a shorter mean optical path length and about 0.04 per cent by volume more nanophase metallic iron particles than the bright area. This clearly shows that space-weathered materials accumulate on small asteroids, which are likely to be the parent bodies of LL chondrites. We conclude that, because LL meteorites are the least abundant of ordinary (H, L, and LL) chondrites, there must be many asteroids with ordinary-chondrite compositions in near-Earth orbits.

Detailed images of asteroid 25143 Itokawa from Hayabusa

Rendezvous of the Japanese spacecraft Hayabusa with the near-Earth asteroid 25143 Itokawa took place during the interval September through November 2005. The onboard camera imaged the solid surface of this tiny asteroid (535 meters by 294 meters by 209 meters) with a spatial resolution of 70 centimeters per pixel, revealing diverse surface morphologies. Unlike previously explored asteroids, the surface of Itokawa reveals both rough and smooth terrains. Craters generally show unclear morphologies. Numerous boulders on Itokawa's surface suggest a rubble-pile structure.

Touchdown of the Hayabusa Spacecraft at the Muses Sea on Itokawa

After global observations of asteroid 25143 Itokawa by the Hayabusa spacecraft, we selected the smooth terrain of the Muses Sea for two touchdowns carried out on 19 and 25 November 2005 UTC for the first asteroid sample collection with an impact sampling mechanism. Here, we report initial findings about geological features, surface condition, regolith grain size, compositional variation, and constraints on the physical properties of this site by using both scientific and housekeeping data during the descent sequence of the first touchdown. Close-up images revealed the first touchdown site as a regolith field densely filled with size-sorted, millimeter- to centimeter-sized grains.

cDNA microarray analysis of cancer associated gene expression profiles in malignant peripheral nerve sheath tumours

BACKGROUND

Malignant peripheral nerve sheath tumour (MPNST) is a highly aggressive malignancy that arises within peripheral nerves, and is associated with poor prognosis. Little is known about the underlying biology of MPNST, especially the mechanisms involved in cell proliferation, invasion, or escape from apoptosis.

AIMS

To identify genes differentially expressed in MPNST compared with benign tumours, such as neurofibromas and schwannomas, by means of cDNA microarray analysis.

METHODS

Six MPNST cases and five benign cases (three schwannomas and two neurofibromas) were analysed.

RESULTS

Six genes (keratin 18, survivin, tenascin C, adenosine deaminase, collagen type VIa3, and collagen type VIIa1) were significantly upregulated in MPNST, whereas one gene, insulin-like growth factor binding protein 6, was downregulated in MPNST. Survivin and tenascin C expression was validated by reverse transcription polymerase chain reaction. Immunohistochemistry confirmed upregulation of survivin in MPNST at the protein level in six of eight cases compared with benign tumours. Tenascin C was also expressed at the invasive front and tumorous stroma in all MPNST cases. MPNST cells expressed tenascin C in four of nine cases.

CONCLUSIONS

Survivin and tenascin C may be associated with the malignant potential of MPNST and could be considered as potential therapeutic targets.