Hybrid Materials Made by Polymerization of the Nanobuilding Blocks {(BuSn)12O14,(OH)6,}2+(AAMPS−)2 (AAMPS = 2-acrylamido-2-methyl-l-propanesulfonate)

The reaction of {(BuSn)12014(OH)6}(OH)2 and 2-acrylamido-2-methyl-1-propanesulfonic acid yields bifunctional nanobuilding blocks, {(BuSn)12,014(OH)6)(AAMPS)2, which carry highly polymerizable acrylamido groups. In such species, the functionalization with polymerizable groups is achieved through electrostatic interaction; the charge compensating anions AAMPS− being located at both poles of the {(BuSn)12O14(OH)6}2+ macrocation. Free radical polymerization of these nanobuilding blocks in THF yields an insoluble material. Solid state 13C CP-MAS NMR of the insoluble fraction (∼70%) indicates that the polymerization of the acrylamido groups is complete. Solid state 119Sn MAS NMR shows that the oxo-hydroxo butyltin core of the nanobuilding blocks is fully preserved in the final material.

Prothrombin G20210A carriers the genetic mutation and a history of venous thrombosis contributes to thrombin generation independently of factor II plasma levels

SUMMARY BACKGROUND

The prothrombin (PT) G20210A gene mutation is a common risk factor for venous thrombosis (VT), which is mainly mediated through an increase in factor II (FII) plasma levels. High FII plasma levels may act through an increase in endogenous thrombin potential (ETP) a key step in hemostasis and thrombosis. While FII may be the main contributor to ETP in PT G20210A carriers, the knowledge of other environmental or genetic factors influencing ETP may help to better identify those at risk of VT.

AIMS

ETP was determined in 472 non-carriers of PT G20210A (PT-) and in 325 unrelated carriers of PT G20210A (PT+) with (symptomatic n = 158) or without (asymptomatic, n = 167) a history of VT. All PT+ were heterozygous and free of other thrombophilic defects.

RESULTS

ETP was higher in asymptomatic PT+ than in PT- (2038 +/- 371 vs. 1616 +/- 267 nmol L(-1) min; P < 0.0001). ETP was significantly higher in symptomatic PT+ than in controls PT+ (2129 +/- 430 vs. 2038 +/- 371 nmol L(-1) min; P = 0.01). Multivariate analyses evidenced the importance of FII and fibrinogen plasma levels in determining ETP.

DISCUSSION

After taking these variables into account, a personal history of VT remained associated with ETP in PT+ carriers. Moreover, PTG20210A still contributes to ETP after consideration of FII levels.

CONCLUSION

In conclusion, the increase in ETP observed in carriers is not entirely explained by higher FII or fibrinogen plasma levels but also by the history of VT.

Subchondral bone in osteoarthritis physiopathology: state-of-the art and perspectives

Osteoarthritis (OA) is the most common form of arthritic disease, and it is a major cause of disability and impaired quality of life in the elderly. A hallmark of the disease is progressive degeneration of articular cartilage and subsequent joint space narrowing. However, OA is a complex disease not limited to cartilage degeneration, but involving also synovial membrane and subchondral bone, thereby presenting alternatives approaches for treatment. In this paper, we propose a short review of the recent advances in the understanding of the role played by subchondral bone in OA.

Stigmasterol: a phytosterol with potential anti-osteoarthritic properties

OBJECTIVE

Although most studies have focused on the cholesterol-lowering activity of stigmasterol, other bioactivities have been ascribed to this plant sterol compound, one of which is a potential anti-inflammatory effect. To investigate the effects of stigmasterol, a plant sterol, on the inflammatory mediators and metalloproteinases produced by chondrocytes.

METHOD

We used a model of newborn mouse chondrocytes and human osteoarthritis (OA) chondrocytes in primary culture stimulated with or without IL-1beta (10 ng/ml), for 18 h. Cells were pre-incubated for 48 h with stigmasterol (20 microg/ml) compared to untreated cells. We initially investigated the presence of stigmasterol in chondrocyte, compared to other phytosterols. We then assessed the role of stigmasterol on the expression of various genes involved in inflammation (IL-6) and cartilage turn-over (MMP-3, -13, ADAMTS-4, -5, type II collagen, aggrecan) by quantitative Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR). Additional experiments were carried out to monitor the production of MMP-3 and prostaglandin E2 (PGE(2)) by specific immuno-enzymatic assays. We eventually looked at the role of stigmasterol on NF-kappaB activation by western blot, using an anti-IkappaBalpha antibody.

RESULTS

After 18 h of IL-1beta treatment, MMP-3, MMP-13, ADAMTS-4, but not ADAMTS-5 RNA expression were elevated, as well as MMP-3 and PGE(2) protein levels in mouse and human chondrocytes. Type II collagen and aggrecan mRNA levels were significatively reduced. Pre-incubation of stigmasterol to IL-1beta-treated cells significantly decreased these effects described above (significant reduction of MMP-3 mRNA in human and mouse, MMP-3 protein in mouse, MMP-13 mRNA in mouse and human, ADAMTS-4 mRNA in human, PGE(2) protein in human and mouse) Finally, stigmasterol was capable of counteracting the IL-1beta-induced NF-kappaB pathway.

CONCLUSION

This study shows that stigmasterol inhibits several pro-inflammatory and matrix degradation mediators typically involved in OA-induced cartilage degradation, at least in part through the inhibition of the NF-kappaB pathway. These promising results justify further ex vivo and in vivo investigations with stigmasterol.

The Effect of the IGF1R Antibody R1507 on ER Positive Breast Cancer Cell Lines Growth and Survival

Background: The insulin-like growth factor-1 receptor (IGF1R) mediates the biological actions of IGF-1 and IGF-2 and is expressed in most breast cancer cells, where receptor activation induces proliferative, cell-survival, and transforming activities. Because crosstalk exists between ER and IGF1R blockade of both pathways could increase antitumor activity. Further, IGF signaling may be enhanced in ER+ cells that have become refractory to long term estrogen deprivation (LTED) explaining resistance to aromatase inhibitor therapy. The effect of the selective IGF1R antibody (R1507) was therefore assessed in a series of breast cancer cell lines in both estrogen-dependent and estrogen-independent growth phases.Methods: The ER positive breast cancer cells lines MCF7, T47D and HCC712 were kept in phenol red-free medium containing 5% charcoal-stripped serum. Several doses of R1507 were used to evaluate effects on cell proliferation, signaling and apoptosis. Western blotting with phospho-specific antibodies was used to observe effects on cell signaling, cell growth was measured using resazurin reduction and apoptosis was quantified by flow cytometry using the TUNEL assay. STED (short-term estrogen deprived) cells were treated with R1507 between 2 and 3 weeks after estrogen depletion and LTED were treated with R1507 after 6+ months of estrogen depletion.Results: R1507 suppressed IGF1R expression and inhibited IGF-1 stimulated IGF1R and AKT phosphorylation in all cell lines. R1507 had anti-proliferative effects in MCF7 cells in both estrogen-dependent and independent growth phases and the magnitude of the effect was similar to fulvestrant. R1507 had a smaller effect on cell proliferation in HCC712 cells and no effects on proliferation were observed in T47D cells. Antibody treatment resulted in significant induction of apoptosis in MCF7 STED but MCF7 LTED cells were resistant to the apoptotic effects of IGF1R blockade.Conclusions: R1507 had an inhibitory effect on IGF1R signaling and an anti-proliferative effect in two of the three cell lines tested. In addition R1507 induced synthetic lethality in combination with acute estrogen deprivation in MCF7 cells, an effect we have recently reported for direct PI3 kinase inhibitors under the same circumstances (1). While the proapoptotic effects of R1507 were lost in the estrogen-independent growth phase of MCF7 cells, the anti-proliferative effect was not, indicating that R1507 might have efficacy in patients with endocrine therapy resistant tumors. In other cell lines the efficacy of R1507 was variable and synthetic lethality was not observed, suggesting that the development of predictive biomarkers for R1507 should be a priority. We are currently addressing the activity of R1507 in a clinical trial with two cohorts, one with acquired resistance to letrozole, where the antibody is added to continued letrozole treatment and a second group of patients with stable disease on letrozole to determine if R1507 can induce tumor regression under these circumstances.1. Crowder et al Cancer Research 69:3955-62, 2009

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3126.

Phosphoinositide-3-Kinase Catalytic Subunit Inhibition Does Not Produce Synthetic Lethality in Estrogen Receptor Positive Breast Cancer Cells with Acquired Resistance to Estrogen Deprivation

Background: Several phosphoinositide-3-kinase (PI3K) catalytic subunit inhibitors are currently in clinical development. However, targeting strategies for PI3K catalytic subunits for treatment in estrogen receptor positive (ER+) disease have not been fully developed. We have recently reported that targeted inhibition of the two major PI3K catalytic subunits, p110α and p110β, using RNA interference (RNAi) induces apoptosis in short term estrogen-deprived ER+ breast cancer cells. Similarly, treatment with BEZ235, a clinical grade p110α/mammalian target of rapamycin (mTOR)-selective inhibitor, also promoted apoptosis in estrogen-deprived ER+ breast cancer cells. Importantly, we found that estradiol significantly suppressed death in ER+ cells induced by inhibition of PI3K catalytic subunits through both RNA interference and BEZ235. In contrast estrogen deprivation or PI3K inhibition individually caused little or no increase in apoptosis, indicating that there is a synthetic lethal interaction with estrogen deprivation/PI3K inhibitor combination treatment in ER+ breast cancer. These data suggest that combining estrogen deprivation with PI3K inhibition may improve clinical outcome by eradicating ER+ cells through increased tumor cell kill. We have extended these studies in order to determine the effect of PI3K catalytic subunit inhibition in long-term estrogen deprived (LTED) cells, a model for acquired resistance to endocrine therapy.Methods: LTED sub-lines of the ER+ MCF7 and T47D breast cancer cell lines were derived by depriving cells of estrogen for 6–9 months in phenol red-free medium containing charcoal-stripped serum after which time cells grow readily without supplemental estrogen. The effects of PI3K inhibition using RNAi and treatment with BEZ235 or BGT226, a p110α-selective inhibitor, were compared in short-term estrogen deprived MCF7 and T47D cells and their LTED derivatives by measuring effects on cell signaling, growth and apoptosis. Cell signaling was evaluated through western blotting, cell growth was measured using resazurin reduction and apoptosis was quantified by flow cytometry using the TUNEL assay.Results: PI3K inhibition using p110α RNAi or treatment with BEZ235 inhibited the growth of MCF7 LTED cells in the absence of supplemental estrogen. However, p110α RNAi or treatment with BEZ235 or the clinical grade p110α-selective inhibitor BGT226 failed to significantly induce apoptosis in MCF7 LTED cells. The effects of PI3K inhibition in T47D LTED cells are under investigation and will be presented.Conclusions: These results suggest that that the efficacy of PI3K inhibitors will be blunted after the onset of acquired resistance to estrogen deprivation through treatment with aromatase inhibitors and that a combined ER/PI3K targeting strategy in ER+ breast cancer treatment should be employed in the endocrine therapy sensitive phase of the disease.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3131.

Curcumin inhibits pro-inflammatory mediators and metalloproteinase-3 production by chondrocytes

OBJECTIVE AND DESIGN

This study aims to investigate the effects of curcumin (Cur) on the extracellular matrix protein metabolism of articular chondrocytes and on their production of inflammatory mediators.

METHODS

Human chondrocytes in alginate beads and human cartilage explants were cultured in the absence or in the presence of interleukin (IL)-1beta (10(-11) M) and with or without Cur (5-20 microM). Nitric oxide (NO) synthesis was measured by the Griess spectrophotometric method; prostaglandin (PG) E(2) by a specific radioimmunoassay; and IL-6, IL-8, aggrecan (Agg), matrix metalloproteinase (MMP)-3, and tissue inhibitor of metalloproteinase (TIMP)-1 by specific enzyme-amplified immunoassays. Proteoglycan degradation was evaluated by the release of (35)S-glycosaminoglycans (GAG) from human cartilage explants.

RESULTS

In alginate beads and cartilage explant models, Cur inhibited the basal and the IL-1beta-stimulated NO, PGE(2), IL-6, IL-8, and MMP-3 production by human chondrocytes in a concentration-dependent manner. The TIMP-1 and the Agg productions were not modified. In the basal condition, (35)S-GAG release from cartilage explants was decreased by Cur.

CONCLUSIONS

Curcumin was a potent inhibitor of the production of inflammatory and catabolic mediators by chondrocytes, suggesting that this natural compound could be efficient in the treatment of osteoarthritis.

Mechanical loading highly increases IL-6 production and decreases OPG expression by osteoblasts

OBJECTIVES

In osteoarthritis (OA), mechanical factors play a key role, not only in cartilage degradation, but also in subchondral bone sclerosis. The aim of this study was to develop on original compression model for studying the effect of mechanical stress on osteoblasts.

MATERIALS AND METHODS

We investigate the effects of compression on primary calvaria osteoblasts isolated from newborn mice and cultured for 28 days in monolayer. At the end of this period, osteoblasts were embedded in a newly synthesized extracellular matrix which formed a three-dimensional membrane. This membrane was then submitted to compression in Biopress Flexercell plates (1-1.7 MPa compressions at 1 Hz frequency) during 1-8h. The expression of 20 genes was investigated by real time reverse transcriptase polymerase chain reaction. Interleukin (IL)-6, matrix metalloproteinase (MMP)-3 and prostaglandin (PG)E(2) were assayed in the culture medium by specific immunoassays.

RESULTS

The compression highly increased IL-6 and cyclooxygenase (COX)-2 mRNA levels in osteoblasts. In parallel, increased amount of IL-6 and PGE(2) was found in the supernatant of loaded osteoblasts. This stimulation reached a maximum after 4h of 10% compression. MMP-2, MMP-3, and MMP-13 mRNA levels were also increased by compressive stress, while 15-hydroxyprostaglandin-dehydrogenase and osteoprotegerin (OPG) start to decrease at hour 4. COX-1, microsomial PG E synthase-1 (mPGES1), mPGES2 and cytosolic PGES and receptor activator of nuclear factor ligand (RANKL) were unmodified. Finally, we observed that alpha 5 beta 1 integrin, intracellular Ca(++), nuclear factor-kappaB and extracellular signal-regulated kinase 1/2 pathways were involved in the compression-induced IL-6 and PGE(2) production. IL-6 neutralizing antibodies and piroxicam inhibited the decrease OPG expression, but did not modify RANKL mRNA level, indicating that IL-6 and PGE(2) induce a decrease of the OPG/RANKL ratio.

CONCLUSION

This work demonstrates that IL-6 is mechano-sensitive cytokine and probably a key factor in the biomechanical control of bone remodeling in OA.

Preservation of Quercus robur germplasm by cryostorage of embryogenic cultures derived from mature trees and RAPD analysis of genetic stability

This study reports on the cryostorage of embryogenic lines derived from selected mature Quercus robur trees, following application of the PVS2-vitrification based procedure. In seven oak genotypes, embryo recovery levels ranging from 57-92% were obtained when 4-6 mg embryo clumps were precultured for 3 days on 0.3 M sucrose basal medium, treated with PVS2 solution for 60 min at 24 degrees C, and then immersed in liquid nitrogen (LN). Embryos of six out of seven lines were cryostored for one week and one year and used to evaluate cryopreservation tolerance, germination ability and to assess genetic fidelity by random amplified polymorphic DNA (RAPD) markers. There were no significant differences between the recovery frequencies of samples retrieved from LN after 1 week and 1 year of cryostorage. In five out of six lines, RAPD profiles of cryopreserved somatic embryos and regenerated plantlets were identical to those of the controls. Although polymorphisms were detected in only one cryostored embryo of one genotype, no genetic instability was found in the regenerated plantlets. This methodology appears to be suitable for long-term storage of this valuable germplasm, as the recovered plantlets were found to be genetically stable.