Metabolomics of basal breast carcinomas: a potential target for treatment intervention

Abstract #6026

Breast cancers of the basal subtype (ER, PR and HER2 negative; EGFR and/or CK5/6 positive) are typically high grade, rapidly proliferative, associated with a poor outcome and are resistant to many chemotherapeutic regimens. They occur more frequently in women with BRCA-1 mutations, African Americans and obese individuals. At the molecular level, basal cancers have impairment of BRCA-1 and p53 signaling and are driven, in part, through EGFR which activates the PI3K/AKT/mTOR pathways. Treatment of basal carcinoma cell lines with the FDA approved anti-diabetic drug metformin significantly reduces cellular proliferation, induces cell cycle arrest (late G1/S phase) and apoptosis in vivo and in vitro. Similar effects were not observed in breast cancer cells of the luminal A, B or HER2 subtypes. Metformin induces a wide spectrum of metabolic and molecular changes in basal carcinoma cell lines in vitro, including: a reduction in glucose uptake, enhanced lactate release, a decrease in cellular proliferation and colony formation, a decrease in EGFR, phospho-EGFR and downstream signaling including pAKT, pMAPK and psrc, inhibition of cyclins D1 and E, reduced E2F1, PARP cleavage and activation of caspases 3, 8 and 9 in a dose and time dependent manner. Nude mice with basal cell line MDA-MB-231 xenografts treated with metformin showed significantly reduced tumor growth and prolonged survival as compared to control untreated mice. Pre-treatment with metformin prior to xenograft inoculation reduced both tumor formation and growth as compared to mice treated with metformin after implantation or untreated control mice, suggesting that metformin may have some use in basal cancer prevention. Epidemiologic data has shown that women treated with metformin have a reduced rate of breast cancer and, for those patients with breast cancer, an improved disease free and overall survival. In aggregate, these data suggest that further study of metformin to prevent or treat breast cancer in some patient subgroups may be indicated.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6026.

Torsional waves propagation along a waveguide of arbitrary cross section immersed in a perfect fluid

Guided torsional waves in a bar with a noncircular cross section have been exploited by previous researchers to measure the density of fluids. However, due to the complexity of the wave behavior in the noncircular cross-sectional shape, the previous theory can only provide an approximate prediction; thus the accuracy of the measurement has been compromised. In this paper, a semianalytical finite element method is developed to model accurately the propagation velocity and leakage of guided waves along an immersed waveguide with arbitrary noncircular cross section. An accurate inverse model is then provided to measure the density of the fluid by measuring the change of the torsional wave speed. Experimental results obtained with a rectangular bar in a range of fluids show very good agreement with the theoretical predictions. Finally, the potentials to use the model for sensor optimization are discussed.

Hsp90{beta} and p130(cas): novel regulatory factors of MMP-13 expression in human osteoarthritic chondrocytes

BACKGROUND

Human osteoarthritic (OA) chondrocytes were previously classified into L (low)- and H (high)-OA according to matrix metalloproteinase-13 (MMP-13) basal levels and interleukin 1beta (IL1beta) inducibility. In H-OA chondrocytes, the regulatory proteins p130(cas) and nuclear matrix protein 4 (NMP4) acting on the MMP-13 promoter were identified.

OBJECTIVE

To identify regulators of MMP-13 expression/production in human L-OA chondrocytes, to determine their effect on the expression of other MMPs and the effect of IL1beta on these molecules.

METHODS

The identification of the L-OA chondrocyte proteins interacting specifically with the AGRE site of the MMP-13 promoter was performed by mass spectrometry. Heat shock protein 90beta (Hsp90beta), p130(cas) and NMP4 small interfering RNAs (siRNAs) were transfected into L-OA chondrocytes and incubated with or without IL1beta. Gene expression was determined by real-time PCR, MMP-1 and MMP-13 production by ELISA, and signalling pathway activation by western blotting and ELISA.

RESULTS

Hsp90beta was identified as a protein of the L-OA/AGRE-specific complex. Silencing p130(cas) and Hsp90beta significantly increased MMP-13 expression (about four- and twofold, respectively) and production. sip130(cas) affected to a lesser extent MMP-1 expression (twofold) and production. siNMP4 showed no effect. Expression of MMP-2, -3, -9 and -14 was unaffected. Silencing both Hsp90beta and p130(cas) had a significant additive effect on MMP-13, but not on MMP-1 expression, the level of which was similar to that with sip130(cas) alone. IL1beta decreased p130(cas) and Hsp90beta expression/production, indicating another pathway by which this cytokine upregulates MMP expression. The IL1beta-triggered signalling pathways responsible for MMP upregulation were unaffected in the silenced cells.

CONCLUSION

This study illustrates the complex regulation of MMP-13 by showing the inhibitory effect of the two cytoplasmic molecules, p130(cas) and Hsp90beta, in L-OA chondrocytes.

Association between CYP2D6 *10 genotype and survival of breast cancer patients receiving tamoxifen treatment

BACKGROUND

Human cytochrome P450 2D6 (CYP2D6) genotype may affect the efficacy of tamoxifen treatment in Caucasian women with breast cancer. The most common polymorphism of CYP2D6 in Chinese women is variant 10 (188 C to T).

PATIENTS AND METHODS

Tamoxifen and 4-hydroxytamoxifen (4OHtam) were measured in the serum of 37 women with breast cancer who were receiving tamoxifen treatment. The association between CYP2D6 *10 genotype and survival was determined in a cohort of 293 women with breast cancer who received tamoxifen (n = 152) or who did not (n = 141).

RESULTS

The serum 4OHtam concentrations were significantly lower in women with the CYP2D6 *10 homozygous variant T/T genotype than in those with the homozygous wild-type C/C genotype (P = 0.04). Among tamoxifen-treated women, women with the T/T genotype had a significantly worse disease-free survival (DFS) than those with the C/C or C/T genotype, and the T/T genotype remained an independent prognostic factor of DFS in multivariate analysis (hazard ratio = 4.7; 95% confidence interval = 1.1-20.0; P = 0.04). Among women who did not receive tamoxifen, there was no significant association between CYP2D6 *10 genotype and survival.

CONCLUSION

In tamoxifen-treated patients, women with the CYP2D6 *10 T/T genotype have a lower 4OHtam level in the serum and a worse clinical outcome.

Biomechanics of femoral deformity in osteogenesis imperfecta (OI): a quantitative approach to rehabilitation

Skeletal deformity is an important characteristic of osteogenesis imperfecta (OI). To study the influence of deformity in stress/strain distribution, a finite element analysis (TEA) of the femur during physiological loading was developed. The diaphysis was altered mathematically to reflect different clinical deformities of OI. Joint reaction and muscle forces were adapted from the literature to reproduce the loading environment at 10% gait cycle (loading response, LR). The goal of the study was to quantitatively describe the stress/strain distribution while comparing the extent of deformity. The results showed that deformity could deteriorate the stress/strain distribution. The study offers a quantitative means for rehabilitative intervention.

Thiamine deficiency induces endoplasmic reticulum stress in neurons

Thiamine (vitamin B1) deficiency (TD) causes region selective neuronal loss in the brain; it has been used to model neurodegeneration that accompanies mild impairment of oxidative metabolism. The mechanisms for TD-induced neurodegeneration remain incompletely elucidated. Inhibition of protein glycosylation, perturbation of calcium homeostasis and reduction of disulfide bonds provoke the accumulation of unfolded proteins in the endoplasmic reticulum (ER), and cause ER stress. Recently, ER stress has been implicated in a number of neurodegenerative models. We demonstrated here that TD up-regulated several markers of ER stress, such as glucose-regulated protein (GRP) 78, growth arrest and DNA-damage inducible protein or C/EBP-homologus protein (GADD153/Chop), phosphorylation of eIF2alpha and cleavage of caspase-12 in the cerebellum and the thalamus of mice. Furthermore, ultrastructural analysis by electron microscopic study revealed an abnormality in ER structure. To establish an in vitro model of TD in neurons, we treated cultured cerebellar granule neurons (CGNs) with amprolium, a potent inhibitor of thiamine transport. Exposure to amprolium caused apoptosis and the generation of reactive oxygen species in CGNs. Similar to the observation in vivo, TD up-regulated markers for ER stress. Treatment of a selective inhibitor of caspase-12 significantly alleviated amprolium-induced death of CGNs. Thus, ER stress may play a role in TD-induced brain damage.

FK506 in the treatment of children with nephrotic syndrome of different pathological types

OBJECTIVE

To evaluate the efficacy of FK506 in the treatment of children with nephrotic syndrome of different underlying pathology.

METHODS

12 patients were treated with FK506 with a dosage of 0.1 - 0.15 mg/kg/d while corticosteroid dose was tapered stepwise. This therapeutic course lasted 3 - 6 months during which the plasma concentration ofFK506 was monitored.

RESULTS

12 children with different pathological types nephrotic syndrome were treated with FK506, including 4 cases of MCN, 6 cases of MsPGN, and 1 case of MPGN and 1 case of FSGS. After 2-month duration, 8 patients got complete remission including 4 cases of MCN and 4 cases of MsPGN and 3 children including 1 case of MsPGN, 1 case of MPGN, and 1 case of FSGS got partial remission. Only 1 child with MsPGN was considered to be a treatment failure. The overall response rate was 91.67% with the plasma concentration of FK506 maintained at 5 approximately 12 ng/ml, and the response time was 10 - 38 days. After 1-month duration, all patients except one experienced a reduction in proteinuria to normal levels or a partial response (50% reduction in protein excretion), significant increase in serum albumin, decrease in serum cholesterol and triglyceride and disappearance of edema. 2 months later, in 11 patients, blood biochemical values had returned to normal levels. The drug was generally well-tolerated. 3 patients had anorexia, nausea, vomiting. 2 patients experienced transient elevated serum creatinine which was reversible after the adjustment of dosage. 3 patients had minor changes in urine NAG. Only 2 of all patients relapsed.

CONCLUSION

FK506 is one of the effective immunosuppressants. In this study, FK506 in combination with a small doses of steroid while decreasing FK506 dosage plays a role in consolidating the curative effect and preventing relapse. In conclusion, FK506 may be effective in the treatment of nephrotic syndrome.

Granzyme K cleaves the nucleosome assembly protein SET to induce single-stranded DNA nicks of target cells

Although granzymes (Gzms) A- and B-induced cell death pathways have been defined, little is known about how other orphan Gzms function in CTL-mediated cytotoxicity. GzmK and A are tryptases among all the Gzms of humans and they are closely linked on the same chromosome. In this study, we showed that GzmK can be efficiently delivered into target cells with a cationic lipid protein transfection reagent Pro-Ject. We found human GzmK triggers rapid cell death independently of caspase activation. The features of death are characterized by rapid externalization of phosphatidylserine, nuclear morphological changes and single-stranded DNA nicks. GzmK hydrolyzes the nucleosome assembly protein SET in its recombinant and native forms or in intact cells. Cleavage of SET by GzmK abrogates its nucleosome assembly activity. After GzmK loading, SET and DNase NM23H1 rapidly translocate into the nucleus and SET is cleaved, where the nuclease activity of NM23H1 is activated to nick chromosomal DNA.

Immunolocalization of matrix proteins in different human cartilage subtypes

Cartilage exerts many functions in different tissues and parts of the body. Specific requirements presumably also account for a specific biochemical composition. In this study, we investigated the presence and distribution pattern of matrix components, in particular collagen types in the major human cartilages (hyaline, fibrous, and elastic cartilage) by histochemical and immunohistochemical means. Macroscopically normal articular cartilages, menisci, disci (lumbar spine), epiglottal, and tracheal tissues were obtained from donors at autopsy. Aurical and nasal cartilages were part of routine biopsy samples from tumor resection specimens. Conventional histology and immunohistochemical stainings with collagen types I, II, III, IV, V, VI, and X and S-100 protein antibodies were performed on paraformaldehyde-fixed and paraffin-embedded specimens. The extracellular matrix is the functional component of all cartilages as indicated by the low cell densities. In particular major scaffold forming collagen types I (in fibrous cartilage) and II (in hyaline and elastic cartilages) as well as collagen type X (in the calcified layer of articular cartilages, the inner part of tracheal clips, and epiglottis cartilage) showed a specific distribution. In contrast, the "minor" collagen types III, V, and VI were found in all, collagen type IV in none of the cartilage subtypes. In this study, we present a biochemical profile of the major cartilage types of the human body which is important for understanding the physiology and the pathophysiology of cartilages.

Enhancement of antitumor activity of the anti-EGF receptor monoclonal antibody cetuximab/C225 by perifosine in PTEN-deficient cancer cells

Mutational inactivation or deletion of the phosphatase and tensin homologue deleted on chromosome 10 (PTEN)/MMAC1/TEP gene in human cancer cells leads to a constitutively active status of the phosphatidylinositol 3-kinase/Akt pathway in the cells and has been linked to the lack of responses of the cells to the epidermal growth factor (EGF) receptor-targeted therapeutics. Akt is strongly inhibited by perifosine, an orally active alkyl-lysophospholipid currently being evaluated as an anti-cancer agent in phase 1 and 2 clinical trials. To determine whether perifosine may enhance the antitumor activity of the anti-EGF receptor monoclonal antibody cetuximab/C225 in PTEN-deficient cancer cells, we exposed MDA468 breast cancer cells (which contain mutated PTEN gene) and PC3 prostate cancer cells (in which the PTEN gene is deleted) to perifosine and cetuximab, alone and in combination. Treatment of the cells with perifosine reduced baseline levels of phosphorylated Akt, phosphorylated p44/42 mitogen-activated protein kinase (MAPK) and p38MAPK, and increased baseline levels of phosphorylated stress-activated protein kinase (SAPK)/c-jun NH(2)-terminal kinase (JNK). A 72-h exposure of the MDA468 and PC3 cells to perifosine alone resulted in cell death in a dose-dependent manner, which was enhanced by cetuximab. Addition of subtoxic doses of perifosine to cetuximab treatment also enhanced the cetuximab-induced growth inhibition. The combination treatment enhanced the inhibition of phosphorylation of Akt, p44/42MAPK and p38MAPK, but offset the phosphorylation of SAPK/JNK that was activated by perifosine treatment alone. Taken together, the data showed that perifosine enhances the antitumor activity of cetuximab in PTEN-deficient cancer cells. Further evaluation of the combination treatment in preclinical and clinical studies is warranted.

[Isolation and characterization of a novel dehydrin gene from Capsella bursa-pastoris]

A novel dehydrin gene designated as Cbcor29 was cloned from Capsella bursa-pastoris by rapid amplification of cDNA ends (RACE) and genome walker technique. The full-length cDNA of Cbcor29 was 1101 bp long with a 783 bp open reading frame (ORF), encoding a putative protein of 261 amino acids. Like other dehydrin proteins, CbCOR29 contained a high percentage of charged and polar amino acids, in which Cys and Trp amino acids were absent. Besides, predicted CbCOR29 protein possesses three conserved repeats of the characterized Lys-rich domains (K-segments), and a Ser-rich domain (S-segment) prior to the first Lys-rich domain, which presented a typical SK3 structure of dehydrins. Analysis of Cbcor29 genomic DNA revealed that it contained 2 exons and 1 intron, which was a typical character of dehydrin genes. Subsequent bioinformatic analysis also showed that the sequence of CbCOR29 had high homology with other dehydrin proteins, especially with cor47 from Arabidopsis thaliana. Moreover, semi-quantitative RT-PCR revealed that the expression of Cbcor29 could be induced by exposure to drought, low-temperature, NaCl and exogenous ABA treatment respectively. Our study implied that the Cbcor29 gene was a new member of the dehydrin gene family and might exert functions in drought-, cold- and salt- responsiveness in Capsella bursa-pastoris.

Tumor suppressor pp32 represses cell growth through inhibition of transcription by blocking acetylation and phosphorylation of histone H3 and initiating its proapoptotic activity

pp32 belongs to a family of leucine-rich acidic nuclear proteins, which play important roles in many cellular processes including regulation of chromatin remodeling, transcription, RNA transport, transformation and apoptosis. pp32 is described as a new tumor suppressor. It is unknown as to how pp32 works in tumor suppression. We found that overexpression of pp32 in human Jurkat T cells inhibits cell growth, and silenced pp32 promotes growth. We first showed that hyperacetylation and hyperphosphorylation of histone H3 are required for T-cell activation. Phosphorylation of histone H3 precedes acetylation during T-cell activation. pp32 specifically binds to histone H3 and blocks its acetylation and phosphorylation. pp32 directly initiates caspase activity and also promotes granzyme A-mediated caspase-independent cell death. Taken together, pp32 plays a repressive role by inhibiting transcription and triggering apoptosis.

Increased fluid secretion after adenoviral-mediated transfer of the human aquaporin-1 cDNA to irradiated miniature pig parotid glands

The treatment of most head and neck cancer patients includes ionizing radiation (IR). Salivary glands in the IR field suffer irreversible damage. Previously, we reported that adenoviral (Ad)-mediated transfer of the human aquaporin-1 (hAQP1) cDNA to rat submandibular glands following IR restored salivary flow to near normal levels. It is unclear if this strategy is useful in larger animals. Herein, we evaluated AdhAQP1-mediated gene transfer after parotid gland IR (20 Gy) in the miniature pig. Sixteen weeks following IR, salivation from the targeted gland was decreased by >80%. AdhAQP1 administration resulted in a dose-dependent increase in parotid salivary flow to approximately 80% of pre-IR levels on day 3. A control Ad vector was without significant effect. The effective AdhAQP1 dose was 2.5 x 10(5) pfu/microl infusate, a dose that leads to comparable transgene expression in murine and minipig salivary glands. Three days after Ad vector administration little change was observed in clinical chemistry and hematology values. These findings demonstrate that localized delivery of AdhAQP1 to IR-damaged salivary glands increases salivary secretion, without significant general adverse events, in a large animal model.

Single-nucleotide polymorphisms in the C-reactive protein (CRP) gene promoter that affect transcription factor binding, alter transcriptional activity, and associate with differences in baseline serum CRP level

To investigate whether functional polymorphisms exist in the C-reactive protein (CRP) gene, i.e., ones that contribute directly to differences in baseline CRP among individuals, we sequenced a 1,156-nucleotide-long stretch of the CRP gene promoter in 287 ostensibly healthy people. We identified two single-nucleotide polymorphisms (SNPs), a bi-allelic one at nucleotide -409 (G-->A), and a tri-allelic one at -390 (C-->T-->A), both resident within the hexameric core of transcription factor binding E-box elements. Electrophoretic mobility shift assays confirmed that the SNP within the sequence (-412)CACGTG(-407) (E-box 1) modulates transcription factor binding, and that the one within (-394)CACTTG(-389) (E-box 2) supports transcription factor binding only when the -390 T allele is present. The commonest of four E-box 1/E-box 2 haplotypes (-409G/-390T) identified in the population supported highest promoter activity in luciferase reporter assays, and the rarest one (-409A/-390T) supported the least. Importantly, serum CRP in people with these haplotypes reproduced this rank order, i.e., people with the -409G/-390T haplotype had the highest baseline serum CRP (mean +/- SEM 10.9 +/- 2.25 microg/ml) and people with the -409A/-390T haplotype had the lowest (5.01 +/- 1.56 microg/ml). Furthermore, haplotype-associated differences in baseline CRP were not due to differences in age, sex, or race, and were still apparent in people with no history of smoking. At least two other SNPs in the CRP promoter lie within E-box elements (-198 C-->T, E-box 4, and -861 T-->C, E-box 3), indicating that not only is the quality of E-box sites in CRP a major determinant of baseline CRP level, but also that the number of E-boxes may be important. These data confirm that the CRP promoter does encode functional polymorphisms, which should be considered when baseline CRP is being used as an indicator of clinical outcome. Ultimately, development of genetic tests to screen for CRP expression variants could allow categorization of healthy people into groups at high versus low future risk of inflammatory disease.

Tactile VR for hand-eye coordination in simulated PTCA

Percutaneous transluminal coronary angioplasty (PTCA) is a minimally invasive image-guided technique for treatment of coronary diseases. PTCA procedure requires physicians to have good skills of hand-eye coordination in performing the operation. Training of PTCA thus very much emphasizes skill building for hand-eye coordination. We have been developing virtual reality (VR) technology for medical simulation. In this paper, we will address the issue of VR-based simulation for the enhancement of hand-eye coordination for PTCA operation. Starting from the characterization of PTCA procedure, we examine what roles VR can play in training of PTCA physicians. We then describe a computerized PTCA training system we have developed which is composed of a tactile interface and a visual interface. The system is designed in such a way that real PTCA devices (including catheters and guide-wires) can be used to mimic the requirements of the CathLab. The backend computational engine supporting the real-time and realistic PTCA simulation is also presented.

Bone intrinsic material properties in three inbred mouse strains

This study assessed genetically based differences in intrinsic material properties of both cortical and cancellous bone in adult females of three inbred mouse strains [C57BL/6J (B6), DBA/2J (D2), C3H/HeJ (C3)]. These mouse strains have previously been shown to differ in bone mineral content (BMC) and density (BMD). Distal femoral cancellous bone and midshaft cortical bone in femurs and tibias were assessed for intrinsic material properties using nanoindentation technique. The intrinsic material properties tested were modulus (E(b)) and hardness (H) of the midshaft femoral and tibial cortical bone cross sections and of cancellous bone in the distal femur. Both femoral and tibial cortical bone intrinsic material properties were different among the three inbred mouse strains. Femoral modulus and tibial hardness in cortical bone and hardness in cancellous bone were either greatest or showed greater trends in C3 mice as compared to both D2 and B6. Cancellous bone modulus was similar among the three mouse strains. With the exception of the D2 mice, the femoral and tibial cortical modulus were similar within each mouse strain. The tibial cortical modulus was smaller than the femoral cortical modulus for D2 mouse strain. The cortical hardness was greater in tibiae compared with that in femora within each mouse strain. The nanoindentation data suggest that cortical and cancellous intrinsic material properties are influenced by the genetic background of the inbred mouse strains. The inbred mouse strain-related intrinsic material property phenotype can be used to locate responsible quantitative trait loci (QTLs) in future studies of recombinant inbred mouse strains.

Molecular and functional characterization of a vasotocin-sensitive aquaporin water channel in quail kidney

Both mammals and birds can concentrate urine hyperosmotic to plasma via a countercurrent multiplier mechanism, although evolutionary lines leading to mammals and birds diverged at an early stage of tetrapod evolution. We reported earlier (Nishimura H, Koseki C, and Patel TB. Am J Physiol Regul Integr Comp Physiol 271: R1535-R1543, 1996) that arginine vasotocin (AVT; avian antidiuretic hormone) increases diffusional water permeability in the isolated, perfused medullary collecting duct (CD) of the quail kidney. In the present study, we have identified an aquaporin (AQP) 2 homolog water channel in the medullary cones of Japanese quail, Coturnix coturnix (qAQP2), by RT-PCR-based cloning techniques. A full-length cDNA contains an 822-bp open reading frame that encodes a 274-amino acid sequence with 75.5% identity to rat AQP2. The qAQP2 has six transmembrane domains, two asparagine-proline-alanine (NPA) sequences, and putative N-glycosylation (asparagine-124) and phosphorylation sites (serine-257) for cAMP-dependent protein kinase. qAQP2 is expressed in the membrane of Xenopus laevis oocytes and significantly increased its osmotic water permeability (P(f)), inhibitable (P < 0.01) by mercury chloride. qAQP2 mRNA (RT-PCR) was detected in the kidney; medullary mRNA levels were higher than cortical levels. qAQP2 protein that binds to rabbit anti-rat AQP2 antibody is present in the apical/subapical regions of both cortical and medullary CDs from normally hydrated quail, and the intensity of staining increased only in the medullary CDs after water deprivation or AVT treatment. The relative density of the approximately 29-kDa protein band detected by immunoblot from the medullary cones was modestly higher in water-deprived/AVT-treated quail. The results suggest that 1) medullary CDs of quail kidneys express a mercury-sensitive functioning qAQP2 water channel, and 2) qAQP2 is at least partly regulated by an AVT-dependent mechanism. This is the first clear identification of AQP2 homolog in nonmammalian vertebrates.

Mutations in SCN9A, encoding a sodium channel alpha subunit, in patients with primary erythermalgia

Primary erythermalgia is a rare autosomal dominant disease characterised by intermittent burning pain with redness and heat in the extremities. A previous study established the linkage of primary erythermalgia to a 7.94 cM interval on chromosome 2q, but the causative gene was not identified. We performed linkage analysis in a Chinese family with primary erythermalgia, and screened the mutations in the two candidate genes, SCN9A and GCA, in the family and a sporadic patient. Linkage analysis yielded a maximum lod score of 2.11 for both markers D2S2370 and D2S2330. Based on critical recombination events in two patients in the family, we further limited the genetic region to 5.98 cM between D2S2370 and D2S2345. We then identified two missense mutations in SCN9A in the family (T2573A) and the sporadic patient (T2543C). Our data suggest that mutations in SCN9A cause primary erythermalgia. SCN9A, encoding a voltage-gated sodium channel alpha subunit predominantly expressed in sensory and sympathetic neurones, may play an important role in nociception and vasomotor regulation.

Regulation of anabolic and catabolic gene expression in normal and osteoarthritic adult human articular chondrocytes by osteogenic protein-1

OBJECTIVE

Osteoarthritis is characterized by dramatic changes in chondrocyte metabolism including the overexpression of catabolic enzymes, but also a lack of anabolic activity. In this respect, osteogenic protein 1 (OP-1) appears to be one of the most potent anabolic factors of chondrocytes. In this study, we were interested in: (1) whether recombinant human OP-1 exerts its anabolic effects also on osteoarthritic chondrocytes, (2) whether OP-1 modulates the expression of catabolic genes, and (3) whether the BMP effects are related to the expression levels of its intracellular mediators (R- and I-Smads).

METHODS

Chondrocytes were isolated from cartilage of either normal (n = 5) or osteoarthritic (n = 8) human knee joints and cultured in short-term high-density monolayer cultures with and without recombinant OP-1. RNA was isolated and analyzed for mRNA expression levels of anabolic (aggrecan, collagen type II), catabolic (MMP-1, -3, -13, ADAMTS-4), and intracellular signaling mediators (Smad 1, 4, 5, 6, 7, and 8) by quantitative online PCR.

RESULTS

After OP-1 stimulation, the anabolic genes were significantly up-regulated in osteoarthritic chondrocytes in comparison to normal chondrocytes. Neither in normal nor osteoarthritic chondrocytes were significant changes observed for the matrix degrading enzymes. Smads were also expressed in both normal and osteoarthritic cells at roughly the same level with and without stimulation with OP-1.

CONCLUSION

Osteoarthritic chondrocytes are not hypo-responsive to anabolic stimulation by OP-1. Thus, human recombinant OP-1 could be a suitable anabolic activator of osteoarthritic chondrocytes. This might be of particular interest as chondrocytes themselves showed very low levels of OP-1 expression.

Congenital lack of COX-2 affects mechanical and geometric properties of bone in mice

We compared the mechanical properties of bones from mice lacking either a functional cycloxygenase-1 (C57BL6/DBA COX-1-/-; n = 9) or COX-2 (C57BL6/DBA COX-2-/-; n = 9) gene and wild type mice (C57BL6/DBA; n = 10). Twenty-eight right femora from 3-month-old male mice were used to determine bulk structural and material properties of bone by three-point bending. Bone matrix properties were also measured by nanoindentation to access the changes in bulk mechanical properties due to changes in bone matrix or bone geometry. The bulk material properties (elastic modulus, P < 0.05; ultimate stress, P < 0.01) of COX-2-/- bones were lower than those of wild-type mice whereas the bulk structural properties (stiffness, P > 0.2; breaking force, P > 0.1) were similar to those of the wild-type mice. COX-2-/- mice had a longer moment of inertia but their cortical bones were thinner and contained many more intra-cortical pores compared with the bones of the other two groups. Finally, the bone matrix properties of COX-1-/- mice, COX-2-/- mice and their heterozygous littermates were similar to those of C57BL6/DBA wild-type mice.

Roles of the PI-3K and MEK pathways in Ras-mediated chemoresistance in breast cancer cells

Activated Ras utilises several downstream pathways, including the mitogen-activated protein kinase (MAPK) kinase (MEK)/MAPK pathway and the phosphoinositide 3-kinase (PI-3k)/Akt pathway, to promote cell proliferation and to inhibit apoptosis. To investigate which pathway plays a major role in Ras-induced drug resistance to chemotherapeutic agents in breast cancer cells, we transfected MCF7 breast cancer cells with a constitutively active H-RasG12V and examined the toxicities of three commonly used breast cancer chemotherapeutic agents, paclitaxel, doxorubicin, and 5-fluorouracil in these cells under the conditions that PI-3K or MEK were selectively inhibited by their respective specific inhibitors or dominant negative expression vectors. We found that Ras-mediated drug resistance is well correlated with resistance to apoptosis induced by anticancer agents in MCF7 breast cancer cells. Although inhibition of MEK/MAPK or PI-3K/Akt can each enhance the cytotoxicity of paclitaxel, doxorubicin, or 5-fluorouracil, inhibition of the PI-3K/Akt pathway seems to have a greater effect than inhibition of the MEK/MAPK pathway in reversing Ras-mediated drug resistance. Our results indicate that the PI-3K pathway may play a more important role in receptor tyrosine kinase-mediated resistance to chemotherapy and suggest that PI-3K/Akt might be a critical target molecule for anticancer intervention in breast cancer.

Molecular characterization of a distinct potyvirus from whitegrass in China

Apotyvirus isolated from perennial whitegrass ( Pennisetum centrasiaticum Tzvel.) in North China was characterized at the molecular level. The 3' terminal nucleotide (nt) sequence of 1669 nt of the viral RNA genome has been determined, which covered the coding region of the C-terminal part of the large nuclear inclusion protein (NIb, RNA polymerase), capsid protein (CP) gene and the 3' nontranslated region (NTR). The CP gene consisted of 909 nt (including the stop codon) encoding 302 amino acid residues, and the 3' NTR was 241 nt in length excluding the polyadenylated tract. Sequence comparison of the amino acids of CPs showed that this virus was most closely related to Sorghum mosaic virus and Maize dwarf mosaic virus with percent identities of 77% to 78% while that of the 3' NTRs suggested that it was most closely related to Zea mosaic virus with identity of 72%. This virus isolate was to some extent closely related to other members of the Sugarcane mosaic virus subgroup of potyviruses for the CP amino acid sequences. Phylogenetic analyses of the sequences indicated that this virus isolate represented a distinct potyvirus, and the name Pennisetum mosaic virus (PenMV) is proposed.

Atomic force microscopy and nanoindentation characterization of human lamellar bone prepared by microtome sectioning and mechanical polishing technique

Surface topography, microstructure, and micromechanical properties of human lamellar bone were characterized by atomic force microscopy and nanoindentation. The lamellar bone surfaces were prepared by two different methods: microtome sectioning and mechanical polishing. The lamellar bone surfaces prepared by mechanical polishing revealed that thin lamellae formed depressions approximately 200 nm deep, whereas the surfaces prepared by microtome sectioning were flat. Atomic force microscopy surface topographic images at higher magnification showed differences between thick and thin lamellae in polished samples, but these differences were less pronounced in microtomed samples. Roughness measurements confirmed that there was a significant difference between thick (21.0 nm) and thin lamellae (8.3 nm) in polished samples (p < 0.001). The difference in surface roughness between thick (13.9 nm) and thin lamellae (12.7 nm) in microtomed sample was statistically insignificant (p = 0.74). Higher elastic modulus values were observed for thick lamella in microtomed samples compared with that of thin lamellae, whereas measured elastic modulus differences between thick and thin lamellae in polished samples were found to be statistically insignificant.

Anisotropic properties of human tibial cortical bone as measured by nanoindentation

The purpose of this study was to investigate the effects of elastic anisotropy on nanoindentation measurements in human tibial cortical bone. Nanoindentation was conducted in 12 different directions in three principal planes for both osteonic and interstitial lamellae. The experimental indentation modulus was found to vary with indentation direction and showed obvious anisotropy (one-way analysis of variance test, P < 0.0001). Because experimental indentation modulus in a specific direction is determined by all of the elastic constants of cortical bone, a complex theoretical model is required to analyze the experimental results. A recently developed analysis of indentation for the properties of anisotropic materials was used to quantitatively predict indentation modulus by using the stiffness matrix of human tibial cortical bone, which was obtained from previous ultrasound studies. After allowing for the effects of specimen preparation (dehydrated specimens in nanoindentation tests vs. moist specimens in ultrasound tests) and the structural properties of bone (different microcomponents with different mechanical properties), there were no statistically significant differences between the corrected experimental indentation modulus (Mexp) values and corresponding predicted indentation modulus (Mpre) values (two-tailed unpaired t-test, P > 0.5). The variation of Mpre values was found to exhibit the same trends as the corrected Mexp data. These results show that the effects of anisotropy on nanoindentation measurements can be quantitatively evaluated.

Molecular genetic profiling of Gleason grade 4/5 prostate cancers compared to benign prostatic hyperplasia

PURPOSE

Because Gleason grade 4/5 cancer is the primary cause of failure to cure prostate cancer, we examined the molecular profiles of this high grade cancer in search of potentially new therapeutic interventions as well as better serum markers than prostate specific antigen.

MATERIALS AND METHODS

We compared the gene expressions in fresh frozen tissues from 9 men with Gleason grade 4/5 cancer to 8 men with benign prostatic hyperplasia (BPH) treated with radical retropubic prostatectomy. Labeled complementary RNA from each of the 17 tissues was applied to HuGeneFL probe arrays representing approximately 6,800 genes (Affymetrix, Inc., Santa Clara, California). After removing all genes undetectable in BPH and grade 4/5 cancers, and transforming the data into a parametric distribution, we chose only those up and down-regulated genes with a p difference in fluorescence between grade 4/5 cancer and BPH of p <0.0005. This value reduced the data set to 40 up-regulated and 111 down-regulated genes. We then eliminated all genes that were not expressed in all 8 BPH and 9 grade 4/5 tissues, which produced a final set of 86 genes, of which 22 were up-regulated and 64 were down-regulated.

RESULTS

Cluster analysis cleanly separated men with grade 4/5 cancers from those with BPH. Only 17 of the 86 candidate genes (20%) were known to be prostate cancer related and 42 (49%) were related to other cancers. The most up-regulated gene is Hepsin, a trypsin-like serine protease with its enzyme catalytic domain oriented extracellularly. Prostate specific membrane antigen is the second most up-regulated gene (all other reports on prostate specific membrane antigen have been at the protein level). The genes for prostate specific antigen (hK3) and human glandular kallikrein2 (hK2) showed equivalent expression levels 10 times the average of other genes. Complete lists of all 22 up-regulated genes and 64 down-regulated genes, together with their locus on the chromosome, are presented in rank order.

CONCLUSIONS

We characterize for the first time 64 down-regulated and 22 up-regulated genes in Gleason grade 4/5 cancer, using the gene profile from BPH as control tissue. A number of interesting new genes, previously undescribed in prostate cancer, are presented as possibilities for further study.

[Comprehensive evaluation of medical system by using generalized fuzzy set theory]

Based on the theory of generalized fuzzy set, a comprehensive evaluation model has been built, which provides residuals estimate, evaluate function and test methods needed. Verified by the prognosis of 30 patients with myocardial infarction in a motion experiment during rehabilitation, its coincidence rate was found to be above 90%. This model can be developed and applied to medical system and other systems for evaluations as well.

Dermal fibroblasts genetically engineered to release nerve growth factor

Current surgical strategies for repair of critical nerves involves the transfer of normal donor nerve from an uninjured body location. One possible alternative to autogenous tissue replacement is the development of engineered constructs to replace those elements necessary for axonal proliferation. Delivery of growth factors is one strategy to enhance synthetic nerve constructs. Thus, this study focused on the delivery of nerve growth factor (NGF) by genetic engineering to begin approaching the microenvironment dictated, in part, by Schwann's cells. Rat dermal fibroblasts (DFBs) were modified genetically to release rat NGF. The reporter gene LacZ was used to assess the optimum nonviral transfection method commercially available before NGF transfection. FuGENE6 provided the optimum transfection efficiency (24% maximum, 20.1 +/- 1.9% 5-day average) as measured by beta-galactosidase catalytic activity. NGF release from transfected DFBs was assessed over a 3-day period. Compared with control (no transfection) DFBs and DFBs transfected with vector alone, DFBs transfected with an expression vector encoding rat beta-NGF demonstrated significantly (p < 0.05) higher levels of NGF, with a 3-day maximum of 111 pg NGF per milliliter. When normalized to cell number, NGF-transfected DFBs released 1.2 pg NGF per milliliter/10(3) cells. The NGF-transfected DFBs demonstrated a maximal NGF release rate at day 1 (1.2 ng NGF/10(6) cells per day), followed by a markedly lower, sustained release rate at days 2 and 3 (0.44 ng NGF/10(6) cells per day and 0.48 ng NGF/10(6) cells per day respectively). The release rate curves for control and vector-transfected DFBs also exhibited a maximal NGF release rate at day 1, but were followed by a decreasing release rate, potentially representing in vitro degradation of NGF present in fetal bovine serum. Although not first with the development of growth factor delivery through fibroblasts, these findings suggest that rat DFBs can be modified genetically to act like Schwann's cells to deliver NGF.

Granzyme A activates an endoplasmic reticulum-associated caspase-independent nuclease to induce single-stranded DNA nicks

The cytotoxic T lymphocyte protease granzyme A (GzmA) initiates a novel caspase-independent cell death pathway characterized by single-stranded DNA nicking. The previously identified GzmA substrate SET is in a multimeric 270-420-kDa endoplasmic reticulum-associated complex that also contains the tumor suppressor protein pp32. GzmA cleaved the nucleosome assembly protein SET after Lys(176) and disrupted its nucleosome assembly activity. The purified SET complex required only GzmA to reconstitute single-stranded DNA nicking in isolated nuclei. DNA nicking occurred independently of caspase activation. The SET complex contains a 25-kDa Mg(2+)-dependent nuclease that degrades calf thymus DNA and plasmid DNA. Thus, GzmA activates a DNase (GzmA-activated DNase) within the SET complex to produce a novel form of DNA damage during cytotoxic T lymphocyte-mediated death.

Time course of the MAPK and PI3-kinase response within 24 h of skeletal muscle overload

Knowledge of the molecular mechanisms by which skeletal muscle hypertrophies in response to increased mechanical loading may lead to the discovery of novel treatment strategies for muscle wasting and frailty. To gain insight into potential early signaling mechanisms associated with skeletal muscle hypertrophy, the temporal pattern of mitogen-activated protein kinase (MAPK) phosphorylation and phosphatidylinositol 3-kinase (PI3-kinase) activity during the first 24 h of muscle overload was determined in the rat slow-twitch soleus and fast-twitch plantaris muscles after ablation of the gastrocnemius muscle. p38alpha MAPK phosphorylation was elevated for the entire 24-h overload period in both muscles. In contrast, Erk 2 and p54 JNK phosphorylation were transiently increased by overload, returning to the levels of sham-operated controls by 24 h. PI3-kinase activity was increased by muscle overload only at 12 h of overload and only in the plantaris muscle. In summary, sustained elevation of p38alpha MAPK phosphorylation occurred early in response to muscle overload, identifying this pathway as a potential candidate for mediating early hypertrophic signals in response to skeletal muscle overload.

Differential roles of p21(Waf1) and p27(Kip1) in modulating chemosensitivity and their possible application in drug discovery studies

In this study, the differential role of the cyclin-dependent kinase (CDK) inhibitors p21(Waf1) and p27(Kip1) in cell cycle regulation was proposed for use in screening natural or synthetic compounds for cell cycle-dependent (particularly M phase-dependent) antineoplastic activity. p21(Waf1) or p27(Kip1) was ectopically expressed with an ecdysone-inducible mammalian expression system in a human colon adenocarcinoma cell line. Induction of p21(Waf1) or p27(Kip1) expression inhibited the activities of CDK2 and completely arrested cells at G(1) phase of the cell cycle by p27(Kip1) and at G(1) and G(2) phases by p21(Waf1). We examined the sensitivity of these cells to several antineoplastic agents known to be cell cycle-dependent or -independent. Substantially increased resistance to cell cycle-dependent antineoplastic agents was found in the cells when the expression of p21(Waf1) or p27(Kip1) was induced. In contrast, only a desensitization to cell cycle-independent antineoplastic agents was found in the cells arrested by p21(Waf1) or p27(Kip1). Because p21(Waf1) induces an additional block at G(2) phase that inhibits cell entry into M phase, we further examined the difference between p21(Waf1)- and p27(Kip1)-induced cells in their sensitivity to D-24851, a novel M phase-dependent compound. We found that induction of p21(Waf1) after exposure of the cells to D-24851 conferred stronger resistance than did induction of p27(Kip1). Taken together, our results suggest that the differential effect of p21(Waf1) and p27(Kip1) on cell cycle regulation may be advantageous for screening chemical libraries for novel antineoplastic candidates that are cell cycle-dependent, and M phase-dependent in particular.

A comparison between microsatellite analysis and cytology of urine for the detection of bladder cancer

We have studied, in a blinded fashion, cytology and microsatellite analysis on urine sediments of 143 Chinese with or without bladder lesions. Microsatellite analysis succeeded in all 143 individuals, while cytology could not be performed on 42 subjects due to insufficient urine samples. Both microsatellite analysis and routine urine cytology succeeded in 81 bladder cancer patients. Seventy-three patients (90%) were identified by microsatellite analysis, while only 41 patients (51%) were identified by cytology. However, four patients were identified by routine cytology but not by microsatellite analysis. Our results proved that microsatellite analysis is more sensitive than routine cytology but the two methods are complementary to each other.

[Clinical value of preserving intercostal-brachial nerve during breast cancer operations]

OBJECTIVE

To study the value of preserving intercostal-brachial nerve during axillary dissection for breast neoplasms.

METHODS

From June 1996 to December 1997, stage I, II breast cancer patients were divided into experimental group (n = 45) and control group (n = 60) respectively. The intercostal-brachial nerve was preserved in the experimental group and not in the control group. Both were followed up after operations.

RESULTS

The postoperation morbidity of arm sensory disturbance was 7.1% in the experimental group, which was significantly different from that of the control group(63.3%, chi2 = 34.69, P < 0.01). No difference was noted in the recurrence rate between the two groups.

CONCLUSIONS

Preserving intercostal-brachial nerve may significantly decrease the morbidity of postoperation arm sensory disturbance during axillary dissection for stage I, II breast cancer patients.

C225 antiepidermal growth factor receptor antibody enhances tumor radiocurability

PURPOSE

Overexpression of epidermal growth factor receptor (EGFR) has been correlated with tumor resistance to radiation. Blockade of EGFR with C225 anti-EGFR antibody was previously shown to synergistically enhance radiation-induced tumor growth delay. The purpose of this study was to assess whether C225 can increase tumor cure by radiation.

METHODS AND MATERIALS

Nude mice bearing 8-mm-diameter A431 tumor xenografts in the hind leg were treated with C225 antibody, graded single doses of local tumor irradiation, or both. C225 was given i.p. at a dose of 1 mg/mouse 6 h before irradiation or 6 h before and 3 plus 6 days after irradiation. Tumor cure was the treatment endpoint assessed by the TCD(50) assay 120 days after treatment. The onset of recurrences of tumors not cured was also determined.

RESULTS

C225 antibody increased the antitumor effects of radiation by reducing TCD(50) values and delaying tumor recurrences. Tumor radiocurability was enhanced by a factor of 1.18 by a single dose and by a factor of 1.92 by three doses of C225. Likewise, the appearance of tumor recurrences was delayed by a factor of 1.37 by a single dose and by a factor of 2.13 by three doses of C225.

CONCLUSION

The data presented here demonstrate that C225 can increase tumor radiocurability and delay the appearance of recurrences of tumors not cured by radiation treatment.

Protection against chemotherapy-induced cytotoxicity by cyclin-dependent kinase inhibitors (CKI) in CKI-responsive cells compared with CKI-unresponsive cells

Inactivation of the retinoblastoma (Rb) protein caused by gene mutation, association with oncoproteins from small DNA viruses, mutational inactivation of p16(Ink4a), or overexpression of cyclin D is a common feature of many human cancer cells and is causally associated with the aberrant proliferation control of cancer cells; whereas normal cells maintain an integrated cell cycle machinery and are subject to cell cycle checkpoint control by cyclin-dependent kinase (CDK) inhibitors (CKIs). To determine whether this difference can be translated into a therapeutic advantage to protect normal cells from adverse cytotoxicity caused by chemotherapy, we established cell model systems for ecdysone-inducible expression of p16(Ink4a), p21(Waf1), and p27(Kip1) in one CKI-responsive cell line (A431 human vulvar epidermoid carcinoma cells with functional Rb) and one CKI-unresponsive cell line (SiHa human cervical cancer cells with nonfunctional Rb). Expression of p16(Ink4a), p21(Waf1), or p27(Kip1) in both SiHa and A431 cells strongly inhibited CDK2 activity, indicating functional expression of the CDK inhibitors in both cell lines. However, only in A431 cells did expression of p16(Ink4a), p21(Waf1), or p27(Kip1) cause Rb dephosphorylation, arrest cell cycle traversal, and potently inhibit cell proliferation. Induction of p16(Ink4a), p21(Waf1), or p27(Kip1) in SiHa cells failed to cause Rb dephosphorylation or to arrest cell cycle traversal, and such induction only minimally inhibited cell proliferation. We then compared the chemosensitivity of clones derived from these two cell lines when the CKIs were and were not induced. Induction of p16(Ink4a), p21(Waf1), or p27(Kip1) conferred strong resistance to paclitaxel- or cisplatin-mediated cytotoxicity on the CKI-responsive A431 cells but not on the CKI-unresponsive SiHa cells. Our results support a novel chemotherapy strategy for treating patients with Rb pathway-impaired cancers by concurrent administration of chemotherapy with CKIs as chemoprotective agents for normal cells.

Involvement of JNK-mediated pathway in EGF-mediated protection against paclitaxel-induced apoptosis in SiHa human cervical cancer cells

We investigated the signalling pathways by which epidermal growth factor (EGF) modulates paclitaxel-induced apoptosis in SiHa human cervical cancer cells. SiHa cells exposed to paclitaxel underwent apoptosis, which was strongly inhibited by EGF. This inhibition of apoptosis by EGF was not altered by pharmacological blockade of phosphatidylinositol 3'-OH kinase (PI-3K) with the PI-3K specific inhibitor LY294002 or blockade of the mitogen-activated protein kinase (MAPK) kinase (MEK) with the MEK specific inhibitor PD98059, or by transfection of the cells with PI-3K or MEK dominant-negative expression vectors. EGF did not stimulate PI-3K/Akt, MEK/MAPK, or p38 MAPK activity in SiHa cells but did transiently activate the c-Jun NH2-terminal kinase (JNK). Co-exposure of SiHa cells to SB202190 at concentrations that inhibit JNK abolished the protective effect of EGF on SiHa cells against paclitaxel-induced apoptosis. Our findings indicate that the JNK signaling pathway plays an important role in EGF-mediated protection from paclitaxel-induced apoptosis in SiHa cells.

[The inhibitory effect of oxymatrine on hepatitis C virus in vitro]

OBJECTIVE

To study the inhibitory effect of oxymatrine on HCV in vitro.

METHODS

SMMC-7721 cells transfected with pBK-HCV using lipofectin transfection protocal were treated with oxymatrine. bDNA signal amplification assay and MTT colorimetric assay were used for intracellular HCV RNA and cytotoxicity.

RESULTS

The stable HCV expression cell model established here could be used as a tool for medicine screen. Oxymatrine at the concentration of 100~1000 mug/ml could significantly decrease the level of intracellular HCV RNA. No cytotoxicity was shown in such concentrations.

CONCLUSIONS

Oxymatrine has an anti-HCV potential activity in vitro.

Poly(ethylene glycol)-conjugated anti-EGF receptor antibody C225 with radiometal chelator attached to the termini of polymer chains

Several biological barriers, including significant liver uptake, limit the clinical application of radiolabeled antibodies in radioimmunoscintigraphy. Here, a general approach is described for radiolabeling of monoclonal antibodies conjugated with poly(ethylene glycol) (PEG). This strategy is demonstrated with C225, a monoclonal antibody directed against epidermal growth factor (EGF) receptor. We synthesized a heterofunctional PEG with one end attached to a radiometal chelator, diethylenetriaminepentaacetic acid (DTPA), and the other end to a protected thiol group, S-acetylthioacetate. After a deprotection step, the resulting DTPA-PEG-SH was conjugated to maleimide-activated C225 to yield DTPA-PEG-C225 conjugate. Characterization of DTPA-PEG-C225 with immunoprecipitation and Western blot analysis revealed that the conjugate was biologically active in binding to the EGF receptor in A431 cells. Competitive EGF receptor binding assay in MDA-MB-468 cells showed that DTPA-PEG-C225, with up to 60% of the amino groups in C225 substituted, retained 66% of C225's binding affinity. Moreover, DTPA-PEG-C225 with increasing degrees of NH(2) substitution from 20% to 70% retained the activity of C225 to induce apoptosis in DiFi cells. More importantly, DTPA-PEG-C225 demonstrated less nonspecific interaction than DTPA-C225. Pharmacokinetic analysis using (111)In-labeled compounds revealed narrower steady-state distribution of (111)In-DTPA-PEG-C225 than (111)In-DTPA-C225, probably due to reduced nonspecific binding of PEG-modified antibody to tissues. The terminal half-life (t(1/2,)(gamma)) of (111)In-DTPA-PEG-C225, 21.1 h, was shorter than that of (111)In-DTPA-C225, 52.9 h. These data suggest that (111)In-DTPA-PEG-C225 may provide better imaging characteristics than (111)In-DTPA-C225, and that using PEG as a linker between the monoclonal antibody and DTPA may be a promising strategy in optimizing the imaging characteristics of immunoscintigraphic agents.

Histone-like proteins from fish are lethal to the parasitic dinoflagellate Amyloodinium ocellatum

Antimicrobial proteins were purified from acid extracts of rainbow trout (Oncorhynchus mykiss) and sunshine bass (Morone saxatilis male x M. chrysops female) skin, gill and spleen by reverse-phase HPLC. Mass spectrometry and amino acid sequence data suggest that these proteins are closely related to histone H2B and histone H1 and thus they were designated histone-like proteins (HLPs). These proteins were lethal to Amyloodinium ocellatum, which is one of the most important parasitic agents affecting fish. Antibiotic concentrations as low as 12.5 microg/ml were inhibitory. Activity was directed against the trophont (feeding) stage of the parasite, while the disseminative (dinospore) stage was unaffected. Thus, HLPs act unlike typical drugs used to treat amyloodiniosis, which usually target the dinospore. Both the ability of the parasite to infect host cells, as well as the ability to grow and differentiate after infection were severely inhibited. This is in contrast to magainin 2, which was similarly toxic to both the dinospore and trophont stages. These findings provide further evidence that histone-like proteins may be important defensive molecules in fish.

The monoclonal antibody 225 activates caspase-8 and induces apoptosis through a tumor necrosis factor receptor family-independent pathway

We previously reported that the anti-epidermal growth factor (EGF) receptor monoclonal antibody (mAb) 225 induces DiFi colon cancer cells to undergo apoptosis, and this apoptosis was accompanied by activation of the two apoptosis initiation caspases, caspase-8 and caspase-9. In the current study, we found that pretreatment of DiFi cells with the caspase-8-specific inhibitor z-IETD-fmk but not pretreatment with the caspase-9-specific inhibitor z-LEHD-fmk inhibited mAb 225-induced apoptosis, indicating that caspase-8 plays an essential role in initiating mAb 225-induced apoptosis. Because caspase-8 is activated primarily by the members of the tumor necrosis factor (TNF) receptor family, such as Fas, TNF receptor-1 (TNFR1), or receptors for TNF-related apoptosis-inducing ligand (TRAIL), we investigated whether mAb 225 activated caspase-8 by regulating one or more of these known pathways. Exposure of DiFi cells to TNFalpha or TRAIL activated caspase-8 and induced apoptosis in the cells. A TNFR1-antagonistic mAb or a TRAIL decoy receptor inhibited the activation of caspase-8 and the subsequent apoptosis induced by TNFalpha or TRAIL, respectively, in the cells. However, neither the TNFR1-antagonistic mAb nor the TRAIL decoy receptor inhibited mAb 225-induced activation of caspase-8 and apoptosis in DiFi cells. DiFi cells express detectable level of Fas but are not sensitive to the treatment by the Fas-agonistic mAb CH-11. A Fas-antagonistic mAb (ZB-4) inhibited the Fas-agonistic mAb CH-11-induced caspase-8 activation and apoptosis in Jurkat T-leukemic cells (used as positive control), but had no effect on mAb 225-induced activation of caspase-8 and apoptosis in DiFi cells. Taken together, our results suggest that mAb 225 does not interact with or regulate these known death receptor pathways. An exploration is therefore warranted for a novel mechanism by which mAb 225 activates caspase-8 and triggers apoptosis in DiFi cells.