Immunological detection of phosphorylation

Incorporation of phosphates into serine, threonine, and tyrosine acceptors in proteins is a common mechanism for regulating protein function. This unit presents protocols that use specific anti-phosphoamino acid (PAA) and anti-phosphoprotein antibodies to detect protein phosphorylation and protein kinase activity. Immunoblotting to detect protein phosphorylation using either anti-PAA or anti-phosphoprotein antibodies. This is a convenient method that usually yields impressive results. Phosphorylation can also be detected by immunoprecipitation followed by immunoblot analysis or by immunofluorescent staining; these methods are typically more complicated and time consuming. All three methods have been successfully used to detect protein phosphorylation with a wide variety of antibodies and most phosphorylated proteins.

Randomized controlled comparative clinical pharmacokinetic study of nab-paclitaxel and solvent-based paclitaxel in Chinese patients (pts) with metastatic breast cancer (MBC)

11505

Background: nab-paclitaxel is a novel solvent-free, 130-nM albumin-bound (nab™) formulation of paclitaxel. In previous studies, nab-paclitaxel demonstrated higher volume of distribution and clearance than that of paclitaxel formulated with Cremophor (Cr-PAC) in Caucasian patients (Sparreboom, Clin Cancer Res 2005;11:4136) and had greater response rate and favorable safety profile in pts with MBC (Gradishar et al., JCO, 2005;23:7794) . The aim of this study was to evaluate nab-paclitaxel blood pharmacokinetics (PK) and compare it with that of Cr-PAC in Chinese MBC patients.Methods: In this randomized controlled, open-label study, patients were assigned to either nab-paclitaxel 260 mg/m2 intravenously (iv) over 30 minutes q3w or Cr-PAC 175 mg/m2 iv over 3 hours q3w. At cycle 1, 12 patients in each treatment group participated in the PK study and then continued treatment until PD or unacceptable toxicity. Plasma samples from pts were analyzed for PK parameters. The primary clinical endpoints were ORR and toxicity (Guan et al; submitted, ASCO, 2007). Results: 24 female pts (median age 44.5 years) participated. No statistically significant between group differences were noted in age, height, weight, or baseline liver function. Paclitaxel blood PK parameters in 2 treatment groups are summarized in the Table. ORR: nab-paclitaxel, 75%; Cr-PAC, 25% (P = 0.018). The maximum grade (G) of neutropenia and neuropathy in the nab-paclitaxel and Cr-PAC groups were G3 and G2, respectively, with no significant between-group difference. Conclusion: nab-Paclitaxel had a greater distribution volume, clearance, and smaller dose adjusted AUC0-inf compared with that of Cr-PAC. There was no significant difference in T1/2 in the 2 groups. PK results in Chinese pts are identical to data reported in Caucasian pts. The lower CL and Vz for Cr-PAC are probably related to sequestration of paclitaxel in the blood by Cremophor. * dose adjusted AUC0-inf

[Table: see text]

[Table: see text]

Randomized study comparing nab-paclitaxel with solvent-based paclitaxel in Chinese patients (pts) with metastatic breast cancer (MBC)

1038

Background: The results of a large clinical study comparing solvent-based paclitaxel 175 mg/m2 with 130-nM albumin-bound paclitaxel (nab-paclitaxel) 260 mg/m2 demonstrated that nab-paclitaxel had greater efficacy and a favorable safety profile in pts with MBC (Gradishar et al., JCO, 2005; 23:7794). The maximum tolerated dose of nab-paclitaxel was 300 mg/m2 infused over 30 minutes without premedication in Chinese pts with solid tumors (Teng et al., Ai Zheng, 2004;23:1431). The aim of this randomized study is to compare the response rates and to evaluate the safety of nab-paclitaxel with those of solvent-based paclitaxel in Chinese pts with MBC. Methods: In this open-label, multicenter study, 210 pts with MBC were assigned to either solvent-based paclitaxel 175 mg/m2 intravenously (IV) over 3 hours every 3 weeks (q3w) with standard premedication (steroids and antihistamines) or nab-paclitaxel 260 mg/m2 IV over 30 minutes q3w with no premedication for 1–6 cycles. The primary endpoints were the overall response rate (ORR, complete or partial response) and toxicity. Stable disease (SD) at =16 weeks was measured. All pts who received at least 1 dose of study drug were evaluable for study endpoints. Results: 210 pts (median age, 50 years; 70% postmenopausal) were enrolled from 29 June 2005 - 1 August 2006. Efficacy results are summarized in the Table . The common toxicities occurring at =20% were alopecia (78%), peripheral neuropathy (75%, 7% gr 3), neutropenia (65%), leucopenia (60%), myalgia (39%), arthralgia (23%), and nausea (21%) and were similar between groups (P = NS). Gr 3/4 neutropenia, measured on days 1 and 8, were similar between groups (p = 0.202). Conclusions: Compared to solvent- based paclitaxel, treatment with nab-paclitaxel was associated with a higher response rate and longer time to progression without increased toxicity. These comparative data in Chinese pts are almost identical to results previously reported in Caucasian pts (Gradishar et al, JCO, 2005).

[Table: see text]

[Table: see text]

Automated sample preparation and purification of homogenized brain tissues

A robotic homogenized tissue sample transferring method has been developed by using a Packard MultiProbe II 8-tip system. It enables robotically transferring homogenized tissue samples from individual test tubes into a 96-well format plate for further sample purification and analysis. Extensive validation has been made to establish the accuracy and variability of this method. This automatic tissue sample transferring approach combined with automatic tissue homogenization, has significantly increased the throughput of tissue sample preparation in screening of drug candidates using liquid chromatography coupled with highly sensitive and selective tandem mass spectrometry (LC-MS/MS).

Analysis of alpha-fetoprotein mRNA level on the tumor cell hematogenous spread of patients with hepatocellular carcinoma undergoing orthotopic liver transplantation

The aim of this study was to detect alpha-fetoprotein (AFP) mRNA levels in the preoperative and intraoperative peripheral blood of patients with hepatocellular carcinoma (HCC) receiving orthotopic liver transplantation (OLT).

METHODS

We detected AFP mRNA by TaqMan real-time reverse transcriptase-polymerase chain reactions (RT-PCR) on the peripheral blood cells (PBCs) from 30 HCC patients undergoing OLT.

RESULTS

In RT-PCR, fluorescence was undetectable in any control. The positive expression rate of AFP mRNA was 23% (7 of 30) in PBC samples of OLT patients preoperatively and 50% (15 of 30) just before hepatectomy during the operation. The positive rate of AFP mRNA in OLT patients at this time was higher than that at preoperation, a difference that was statistically significant (P < .01).

CONCLUSION

The OLT operation induced release of cells from the liver into the peripheral blood circulation. This may be an important mechanism of liver cancer cell dissemination deserving further investigation.

Two eudesmane sesquiterpenes from Laggera pterodonta

Two new eudesmane sesquiterpenes, 2alpha-hydroxy pterodontic acid (1) and pterodolide [3alpha-(2-methyl-2,3-epoxy)-butyric-4alpha-acetoxy-8beta-ethoxy eudesma-7(11)-en-8alpha,12-olide (2), along with five known compounds (3-7) were isolated from the aerial parts of Laggera pterodonta. Their structures were elucidated on the basis of spectroscopic methods. The immunosuppressive activity of the isolated compounds was investigated.

The Expression of von Willebrand Factor, Soluble Thrombomodulin, and Soluble P-Selectin During Orthotopic Liver Transplantation

BACKGROUND

We evaluated von Willebrand factor (vWF), soluble thrombomodulin (sTM), and soluble P-selectin (sP-selectin) levels in ischemia/reperfusion injury during orthotopic liver transplantation (OLT).

METHODS

The vWF, sTM, and sP-selectin were analyzed in 20 patients who underwent liver transplantation. Blood samples were drawn from the radial artery at serial times during surgery. Plasma levels of sTM and sP-selectin were detected by enzyme-linked immunosorbent assay (ELISA). The wWF activity was measured using the immuno-turbidimetric method. Plasma aspartate transaminase (AST) and alanine transaminase (ALT) were assayed by routine clinical chemistry testing.

RESULTS

Marked elevation levels of plasma AST and ALT were released during the 15 minutes after reperfusion phase, with a peak on the first postoperative day (P < .01). The sTM level remained unchanged from preoperative to anhepatic phase (P > .05). In contrast, a mean 2.5-fold increase of sTM was observed during the 15-minute reperfusion stage compared with the preoperative value (P < .01). The vWF activity only showed significant increase during the 60-minute reperfusion stage compared with the preoperative value (P < .05). No significant increase occurred in sP-seletin levels during the reperfusion phase. Platelet count showed significant decrease during the entire observation period compared with the preoperative value (P < .01).

CONCLUSION

The endothelial reperfusion injury after OLT is characterized by increased vWF and sTM but not by sP-selectin in peripheral blood.

Evidence for a distinct group of nestin-immunoreactive neurons within the basal forebrain of adult rats

Nestin is an intermediate filament protein serving as a marker for neuroprogenitor and stem cells. Here we report that a cluster of previously unrecognized nestin immunoreactive (nestin-ir) neurons was located in the medial septum-diagonal band of Broca (MS-DBB) of the basal forebrain in adult rats. Nestin-ir neurons were exclusively located in the MS-DBB and intermingled with choline acetyltransferase-ir (ChAT-ir), parvalbumin-ir (PV-ir), or nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase reactive (NADPHd-reactive) neurons. However, there was no colocalization between nestin-ir and PV-ir in single neurons in MS-DBB; only about 35% of nestin-ir neurons were ChAT-ir, and 8%-12% of nestin-ir neurons were NADPHd-reactive. Morphologically, nestin-ir neurons showed a larger size of somata than that of ChAT-ir or PV-ir neurons and the distribution of nestin-ir neurons spread across the rostro-caudal extent of the MS-DBB. Moreover, retrograde tracing revealed that a significant portion of these nestin-ir neurons projected to the thalamus and hippocampus. These results, for the first time, provide strong evidence that there exists a cluster of previously unrecognized nestin-ir neurons in MS-DBB of the basal forebrain in adult rats and that these nestin-ir neurons are distinguishable from ChAT-ir, PV-ir, and NADPHd-reactive neurons.

Dendritic plasticity of CA1 pyramidal neurons after transient global ischemia

Dendrites and spines undergo dynamic changes in physiological conditions, such as learning and memory, and in pathological conditions, such as Alzheimer's disease and epilepsy. Long-term dendritic plasticity has also been reported after ischemia/hypoxia, which might be compensatory effects of surviving neurons for the functional recovery after the insults. However, the dendritic changes shortly after ischemia, which might be associated with the pathogenesis of ischemic cell death, remain largely unknown. To reveal the morphological changes of ischemia-vulnerable neurons after ischemia, the present study investigated the alteration of dendritic arborization of CA1 pyramidal neurons in rats after transient cerebral ischemia using intracellular staining technique in vivo. The general appearance of dendritic arborization of CA1 neurons within 48 h after ischemia was similar to that of control neurons. However, a dramatic increase of dendritic disorientation was observed after ischemia with many basal dendrites coursed into the territory of apical dendrites and apical dendrites branched into the region of basal dendrites. In addition, a significant increase of apical dendritic length was found 24 h after ischemia. The increase of dendritic length after ischemia was mainly due to the dendritic sprouting rather than the extension of individual dendrites, which mainly occurred in the middle segment of the apical dendrites. These results reveal a plasticity change in dendritic arborization of CA1 neurons shortly after cerebral ischemia.

Tumor necrosis factor prevents alendronate-induced osteoclast apoptosis in vivo by stimulating Bcl-xL expression through Ets-2

OBJECTIVE

To investigate why bisphosphonates are less effective at preventing focal bone loss in rheumatoid arthritis (RA) patients than in those with generalized osteoporosis, and the mechanisms involved.

METHODS

The response of osteoclasts to alendronate (ALN) in tumor necrosis factor-transgenic (TNF-Tg) mice that develop erosive arthritis and in wild-type littermates was studied. TNF-Tg and wild-type mice were given ALN, and the osteoclast numbers in the inflamed joints and in the long bones were compared. The expression levels of Bcl-xL in the osteoclasts of TNF-Tg and wild-type mice were examined by immunostaining. The effect of overexpression of Bcl-xL and Ets-2 proteins on ALN-induced osteoclast apoptosis was determined using an in vitro osteoclast survival assay and retrovirus transfer approach.

RESULTS

ALN reduced osteoclast numbers in the metaphyses by 97%, but by only 46% in the adjacent inflamed joints. Bcl-xL expression was markedly higher in osteoclasts in the joints than in those in the metaphyses of TNF-Tg mice. Bcl-xL or Ets-2 overexpression protected osteoclasts from ALN-induced apoptosis, and TNF stimulated Bcl-xL and Ets-2 expression in osteoclasts. Overexpression of Ets-2 increased Bcl-xL messenger RNA in osteoclasts, while a dominant-negative form of the Ets-2 blocked the protective effect of Bcl-xL or TNF on ALN-induced apoptosis.

CONCLUSION

The reduced efficacy of bisphosphonates to stop bone erosion in the inflamed joints of RA patients may result from local high levels of TNF up-regulating Ets-2 expression in osteoclasts, which in turn stimulates Bcl-xL expression in them and reduces their susceptibility to bisphosphonate-induced apoptosis.

Validation of rat endometriosis model by using raloxifene as a positive control for the evaluation of novel SERM compounds

Approximately 10% of women of reproductive age suffer from endometriosis, a potentially painful disease process and important cause of female infertility. Raloxifene, a commercially available SERM (selective estrogen receptor modulator) compound, used for the treatment of postmenopausal osteoporosis, has preclinically demonstrated its estrogen antagonist effect on uterine tissue in rats. There is potential that SERM compounds may become a viable treatment option for human endometriosis, although more investigation is needed. In this study, raloxifene was administered at various doses to determine the efficacy and an appropriate dose level for use as a positive control in a rat model of endometriosis. Prior to dose administration, all rats underwent a bilateral ovariectomy, autologous transplantation of uterine tissue onto the peritoneal surface of the abdominal wall, and implantation of a subcutaneous estrogen pellet (E2). Two separate postsurgical experiments were performed. In experiment 1, following a 4-wk recovery, the rats bearing implants were assigned to three groups: (1) removal of the E2 pellet and dosing vehicle only (n = 7); (2) E2 and vehicle (n = 6); and (3) E2 and raloxifene at 10.0 mg/kg (n = 6). In experiment 2, also following a 4-week recovery, the rats bearing implants were assigned to five groups (n = 8/group): (1) E2 and vehicle only; (2) E2 and raloxifene, 0.3 mg/kg/d; (3) E2 and raloxifene, 1.0 mg/kg/d; (4) E2 and raloxifene, 3.0 mg/kg/d; (5) E2 and raloxifene, 10.0 mg/kg/d. All rats were dosed orally BID for 14 d. At the end of the study, the implanted endometrium was remeasured and compared to the pretreatment measurement. The results from both studies demonstrated that Raloxifene at only one dose (10.0 mg/kg) displayed significant implant regression (p < .05). Subsequently, our rat endometriosis experimental model consistently uses the exogenous E2 pellet and raloxifene at 10 mg/kg, BID, as a positive control to help screen and compare novel SERM compounds.

Association analysis of the variant in the regulatory subunit of phosphoinositide 3-kinase (p85alpha) with Type 2 diabetes mellitus and hypertension in the Chinese Han population

AIMS

To determine whether variants in the gene for the regulatory subunit of phosphoinositide 3-kinase (p85alpha) are associated with Type 2 diabetes mellitus (Type 2 DM) and hypertension in a Chinese population.

METHODS

We performed a case-control study genotyping the Met326Ile and IVS4+82A>G polymorphisms in 494 patients with Type 2 DM and hypertension and 557 normal controls from the north of China. Individual genotypes were identified by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The IVS4+82A>G polymorphism was further confirmed by direct sequencing in 20 randomly selected cases.

RESULTS

The IVS4+82A>G polymorphism that is common in Caucasians was not detected in our population. Frequencies of genotypes and alleles of Met326Ile polymorphism were not significantly different between cases and controls in whole samples by univariate analysis. Logistic regression analysis demonstrated that Ile326Ile genotype was associated with a 2.085-fold (95% CI, 1.043-4.168, P = 0.0377) relative risk of diabetes and hypertension. After stratification by obesity, the frequency of Ile326Ile genotype in cases was higher than that in controls (18/304 vs. 13/510, P = 0.015) among non-obese individuals (BMI < 28 kg/m2). We did not find that this missense mutation was associated with blood pressure, glucose and blood lipids in the control group.

CONCLUSION

Our data indicate that the Met326Ile variation in the gene encoding the p85alpha protein might contribute to the increased risk of Type 2 DM and hypertension in Chinese.

Metabolism and disposition of gemfibrozil in Wistar and multidrug resistance-associated protein 2-deficient TR- rats

1. The roles of multidrug resistance-associated protein (Mrp) 2 deficiency and Mrp3 up-regulation were evaluated on the metabolism and disposition of gemfibrozil. 2. Results from in vitro studies in microsomes showed that the hepatic intrinsic clearance (CLint) for the oxidative metabolism of gemfibrozil was slightly higher (1.5-fold) in male TR- rats, which are deficient in Mrp2, than in wild-type Wistar rats, whereas CLint for glucuronidation was similar in both strains. 3. The biliary excretion of intravenously administered [14C]gemfibrozil was significantly impaired in TR-) rats compared with Wistar rats (22 versus 93% of the dose excreted as the acyl glucuronides over 72 h). Additionally, the extent of urinary excretion of radioactivity was much higher in TR- than in Wistar rats (78 versus 2.6% of the dose). 4. There were complex time-dependent changes in the total radioactivity levels and metabolite profiles in plasma, liver and kidney, some of which appeared to be related to the up-regulation of Mrp3. 5. Overall, it was demonstrated that alterations in the expression of the transporters Mrp2 and Mrp3 significantly affected the excretion as well as the secondary metabolism and distribution of [14C]gemfibrozil.

Characterisation of cartilage intermediate layer protein (CILP)-induced arthropathy in mice

OBJECTIVES

To characterise cartilage intermediate layer protein (CILP)-induced arthropathy in mice.

METHODS

The first and second halves of the nucleotide triphosphate pyrophosphohydrolase (NTPPHase) non-homologous region of human CILP were prepared as recombinant proteins (C1 and C2, respectively), including three overlapping fragments of C2 (C2F1, C2F2, and C2F3). C57BL/6 mice were immunised with these proteins to induce arthritis. In addition, a separate group of mice were immunised repeatedly with the mixture of C1 and C2 to see the effect of chronic immunisation. Arthritis developed in the mice, and cellular and humoral immune responses against CILP were analysed.

RESULTS

Immunisation with C2 and with the mixture C2F1/C2F2/C2F3 caused the severest arthritis to develop in mice. Immunisation with one of C1, C2F1, C2F2, or C2F3 caused milder arthritis, even though each of the fragments carried T cell epitopes. Immunisation either with C1 or C2 alone evoked cellular and humoral immune responses to both the C1 and C2 proteins. Further, the repeated immunisation with the C1/C2 mixture caused tendon calcification and bone irregularity, together with decreased NTPPH activity.

CONCLUSIONS

The results show that multiple T cell epitopes are needed for the development of CILP-induced arthritis, and present the characteristic new model of mild arthropathy accompanied by extra-articular calcifications. An immune response to putative murine CILP/NTPPH may be involved in the ectopic calcifications in the arthritic mice.

Genomic organization of human TCF12 gene and spliced mRNA variants producing isoforms of transcription factor HTF4

The human TCF12 gene, mapping to 15q21, encodes the helix-loop-helix transcription factor 4 (HTF4). A detailed analysis of this genomic region established the organization of the TCF12 gene. The gene includes 21 exons and is significantly larger than an average human gene. Preceding the second exon, two alternative acceptor sites for mRNA splicing yield two distinguishable transcripts (HTF4a and HTF4b) which differ in their 5' untranslated region but share identical coding sequences. Differential utilization of exon 15 in the TCF12 gene may reflect a mechanism producing a cell-type-specific protein (HTF4c). In addition, intron 5 in the TCF12 gene corresponds to the region involved in a translocation, t(9;15)(q22;q21), that results in a form of extraskeletal myxoid chondrosarcoma.