Formation of Buried Porous Silicon Structure by Hydrogen Plasma Immersion Ion Implantation

Plasma Immersion Ion Implantation (PIII) excels in several areas over conventional ion implantation, for example, higher dose, shorter implantation time, and lower overall cost. The technique can be used to fabricate buried porous silicon. In our experiment, hydrogen is implanted into Si by PIII at 5–30kV to form underlying porous silicon (PS) which emits light at an energy higher than the Si bandgap. The optical properties of the PS samples as measured by photoluminescence are quite good. The PHI technique therefore offers an alternative means to fabricate buried porous silicon structures which can potentially be used to fabricate optoelectronic devices in silicon.

Abstract P6-03-04: Opening, Dynamic Prospective Cohort Research on the Small Focus Less than 1.1cm Shown by B Ultrasound in Breast

BACKGROUND: Ultrasound is the most frequent clinical way to examine breast in China. Because Chinese have small and high density breasts, mammography can not show some lesions, and it costs too much. There are 5%-10% patients detected small, nonpalpable lesions by ultrasound in clinic and physical examination. Most of the lesions are very small, without typical characteristics of malignant or benign tumor. So many positive results bother doctors and patients. OBJECTIVE To find an appropriate way to detect breast cancer early and reduce unnecessary biopsy. METHODS: A Opening, dynamic prospective cohort research on the small focus less than 1.1cm shown by B ultrasound has been performed from 1 st January 2009. 791 cases and 1064 lesions were selected to the study group. All patients are female, from 35 to 75 years old. The lesions are from 0.25 cm to 1.1cm in ultrasound and less than grade 3 in mammography according to BI-RADS. The patients are divided to 2 groups according to the mammography grade of BI-RADS. The first subgroup concludes 260 cases with grade 3, and the second subgroup concludes 531 cases with less than grade 2. The patients who were more than grade 4 in ultrasound according to BI-RADS accepted biopsy as soon as they got into group. Other patients accept ultrasound per 3 months and mammography per year. We will do biopsy when the lesions rise up to 130% of the original size, and when the lesion reduce to 70% of the original size in consecutive two times examination on ultrasound , the patient will leave the group. RESULTS: Total 70 cases were performed biopsy during 17months. 2 cases (0.7%) without family history of breast cancer were breast cancer during biopsy in the first subgroup.2 cases (0.3%) with family history of breast cancer were mastopathy with atypia during the procedure of follow up—biopsy in the second subgroup. CONCLUSIONS: Most small lesions which are negative on mammography are benign and need not be performed resection. Use of mammography can reduce unnecessary biopsy in Chinese. Ultrasound and family history of breast cancer should be considered well.

the cases of screening and biopsy

Abstract P1-01-27: Level III and Interpectoral Lymph Nodes Involvement in Breast Cancer with Positive Axillary Lymph Nodes after Neoadjuvant Chemotherapy

Background: In the era of sentinel node biopsy (SNB), mainly aimed at local control, the axillary dissection (AD) was performed for breast cancer with positive node. It was argued that only level I/II lymph nodes dissection might be inadequate because nodes involvement was found in level III and interpectoral region when axillary node was positive. It is necessary to assess the extent of AD after modern preoperative axillary staging. The aim of this study was to investigate the incidence and associated factors of node involvement in level III/interpectoral region. Methods: A consecutive series of 338 core needle biopsy confirmed T0-2 invasive breast cancer cases were included in this study. Axillary node metastases were proved by ultrasound guided needle biopsy (NB) if ultrasonographic abnormal node was detected prior to SNB or by SNB if no abnormal node was detected. Cases of negative NB but positive SNB with image abnormal node were excluded. Prior to AD included level III and interpectoral lymph nodes, 4 to 8 cycles of neoadjuvant chemotherapy with anthrocyclin and/or taxane regimen were completed for each case. The chi-square test was used to determine the relation between level III/interpectoral lymph nodes metastases and clinicopathological factors. Multivariate logistic regression was analyzed for covariate selection. Results: A median of 19 axillary nodes was harvested per case (range: 5-46, average: 19.2). The pathologic complete response rate of axillary nodes was 35.3% (70/198) in NB positive subgroup. Level III and interpectoral lymph nodes were harvested in 76.9% (260/338) of cases (range: 1-8, average: 1.9, median: 1) and 49.7% (168/338) of cases (range: 1-10, average: 1.6, median: 1), respectively. The incidence of positive level III and interpectoral lymph nodes were 8.9% (30/338) and 8.9% (30/338), respectively. Node involvement of level III/interpectoral region was found in 13.3% (45/338) of these cases. The incidence of node involvement in level III/interpectoral region of NB positive subgroup (14.6%, 29/198) was not significantly higher compared with SNB positive subgroup (11.4%, 16/140, P=0.391). Increasing tumor size was significantly correlated with increasing likelihood of node involvement in level III/interpectoral region (T0-1: 6.3% vs T2: 16.7%, P=0.008). In SNB positive T0-1 subgroup, there was no positive node found in level III/interpectoral region. Multivariate analysis showed that tumor size was the only independent factors predicting node involvement in level III/interpectoral region (OR=3.488, 95%CI:1.427-8.528, P=0.006).

Conclusions: The incidence of node involvement in level III/interpectoral region was 13.3% of nodes positive T0-2 breast cancer treated with neoadjuvant chemotherapy. Tumor size may be the predictor of node involvement in this region.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-27.

Micromachining a miniaturized capillary electrophoresis-based chemical analysis system on a chip

Micromachining technology was used to prepare chemical analysis systems on glass chips (1 centimeter by 2 centimeters or larger) that utilize electroosmotic pumping to drive fluid flow and electrophoretic separation to distinguish sample components. Capillaries 1 to 10 centimeters long etched in the glass (cross section, 10 micrometers by 30 micrometers) allow for capillary electrophoresis-based separations of amino acids with up to 75,000 theoretical plates in about 15 seconds, and separations of about 600 plates can be effected within 4 seconds. Sample treatment steps within a manifold of intersecting capillaries were demonstrated for a simple sample dilution process. Manipulation of the applied voltages controlled the directions of fluid flow within the manifold. The principles demonstrated in this study can be used to develop a miniaturized system for sample handling and separation with no moving parts.

Amitosis-like nuclear division in erythrocytes of triploid rainbow trout Oncorhynchus mykiss

This work shows that the atypical erythrocytes in triploid rainbow trout Oncorhynchus mykiss were morphologically similar to those of toads. The nuclei of the cells can be bell-shaped, constricted or irregular. It is presumed that such nuclear division is probably amitosis.

Selective Effects of Glucose, Insulin and Leptin by Molecular Breast Cancer Subtype

Background: Type II diabetes and obesity are important risk factors for post-menopausal luminal A (LA) and triple negative (TN) pre-menopausal breast cancers, particularly in African American (AA) and Hispanic women. Breast cancer patients with these chronic metabolic diseases also have a worse prognosis, independent of other factors. We have published that metformin inhibits cell growth (S phase arrest) and induces apoptosis, only in TN cell lines in vivo and in vitro. It is less active, growth inhibitory (G1 arrest) and does not induce apoptosis in other breast cancer cell subtypes (Cell Cycle, 2009).Methods: We investigated the effects of glucose as a mitogen at physiologic (5mM), metabolic syndrome (7mM) or diabetic levels (10mM), with or without insulin (100 ng/ml) or leptin (100 ng/ml) using cell lines representing all molecular subtypes of breast cancer. Metformin was then used in combination with the above, to determine whether it would block the mitogenic or signaling effects of supraphysiological glucose, insulin or leptin.Results: The LA (MCF-7) and 2 of 5 TN cell lines (derived from AA patients; HCC 1806 and MDA 468) showed the most cell growth in response to glucose >5mM (75% for MCF-7, 30-50% for AA TN lines). Three TN cell lines from Caucasians (MDA231, HCC1937, BT20), the HER2 (SKBR3) and luminal B (BT-474) cells showed less growth induction with glucose >5mM. In TN lines only, glucose associated mitogenesis was associated with increased EGFR, pEGFR, IGF1R, pIGF1R, AKT and pAKT and decreases in AMPK, pAMPK, p38, IRS2, and the cyclins D1, E and A in a dose dependent manner. Metformin abrogated glucose induced cell growth and the aforementioned protein expression/phosphorylation changes involving EGFR, IGF1R, and AKT, increased AMPK and pAMPK and induced a profound reduction in Cyclin D1 across all glucose concentrations in TN cell lines from AA women. It reduced but did not eliminate glucose associated mitogenesis in the TN cell lines from Caucasian patients. Metformin had a more variable effect on cell lines of other molecular subtypes grown under high glucose conditions. The 5 TN breast cancer cell lines were uniformly resistant to both leptin and insulin associated mitogenesis, across a wide range of glucose concentrations. In contrast, both leptin and insulin significantly promoted LA breast cancer cell growth. These effects were resistant to metformin treatment. Leptin and insulin had the least growth promoting effects on HER2 breast cancer cell lines, whereas they induced modest growth induction in LB cell lines.Conclusions: All TN cell lines showed significant mitogenesis in response to glucose >5mM, whereas they were uniformly resistant to both leptin and insulin. The glucose associated mitogenesis was more pronounced in lines derived from AA patients, as were the anti-mitgenic effects of metformin. LA cells showed marked growth induction by glucose, leptin and insulin, whereas HER2 cell lines showed general resistance to all of these factors. These data suggest that metabolic and hormonal shifts with obesity and diabetes, as well as metformin response vary by the molecular subtype of breast cancer cells and ethnicity.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5154.

Metformin Enhances Trastuzumab Efficacy and Overcomes Resistance in HER2 Type Breast Cancer Cells

Background: HER2 alterations occur in one-fourth of breast cancers and are associated with an aggressive tumor phenotype. The anti-HER2 agent trastuzumab reduces cell proliferation, angiogenesis, DNA repair and induces antibody-dependent cellular cytotoxicity. Objective response rates and median duration of response for eligible patients given trastuzumab alone is low (12-34% and 9 months respectively), hence, it is administered in combination with other agents. Mechanisms of trastuzumab resistance include: altered receptor antibody interactions, increased signaling through other EGFR type I growth factor receptors, modulation of p27 kip1 and increased insulin-like growth factor 1 receptor (IGF-1) signaling. We have reported that metformin inhibits HER2 expression, tyrosine kinase activity (phosphorylated HER2 at both auto- and Src- phosphorylation sites), AKT/mTOR signaling, Cyclin D1 and E2F1 with G1 arrest in HER2 overexpressing breast cancer cells. We sought to determine if metformin would enhance trastuzumab associated cytotoxicity and modulate acquired resistance in vitro.Methods: We used trastuzumab sensitive (SKBR3, BT474) and resistant cell lines (BT-474/HR20, SKBR3/P2, MCF-7/713 and MCF-7/HER2Δ16) to study the effects of metformin, metformin + trastuzumab and trastuzumab alone. Assays included MTS for proliferation, clonogenicity studies, Western blots, and pull down experiments with Western blots.Results: Trastuzumab sensitive breast cancer cells were less sensitive to metformin alone, compared to trastuzumab resistant HER2 subtype breast cancer cell lines. Trastuzumab sensitive cells showed enhanced growth and clonogenicity inhibition when treated by both metformin and trastuzumab. At the molecular level, these bi-treated cells showed decreases in HER2/pHER2, erbB3/perbB3, and inactivation of AKT and MAPk signaling. Metformin as low as 20mM increased the efficacy of trastuzumab. All HER2 resistant cell lines showed higher levels of IGF1R and HER2/IGF1R complexes, as compared to sensitive parental lines. In these resistant lines Metformin decreased cell proliferation and clonogenicity, HER2/IGF1R complexes (identified through pull down experiments) and protein expression of HER2/pHER2, erbB3/perbB3, IGF1R/pIGF1R as well as downstream signaling via Akt and IGF1 pathways. Metformin overcame trastuzumab resistance as demonstrated by growth and clonogenicity assays.Conclusions: HER2 amplified trastuzumab resistant breast cancer cells showed greater sensitivity to metformin than sensitive parental lines. Metformin reversed trastuzumab resistance and decreased HER2:IGF1R complexes, HER2/pHER2 and IGF1R expression, whereas sensitive parental lines showed no complex formation. These preclinical data suggest a combination of metformin and trastuzumab may have clinical benefit, improving the efficacy and reducing the emergence of or reversing trastuzumab resistance in HER2 positive breast cancer patients.Herceptin graciously provided by Genentech

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1133.

Intracellular delivery and calcium transients generated in sonoporation facilitated by microbubbles

Ultrasound application in the presence of microbubbles is a promising strategy for intracellular drug and gene delivery, but it may also trigger other cellular responses. This study investigates the relationship between the change of cell membrane permeability generated by ultrasound-driven microbubbles and the changes in intracellular calcium concentration ([Ca(2+)](i)). Cultured rat cardiomyoblast (H9c2) cells were exposed to a single ultrasound pulse (1MHz, 10-15cycles, 0.27MPa) in the presence of a Definity(TM) microbubble. Intracellular transport via sonoporation was assessed in real time using propidium iodide (PI), while [Ca(2+)](i) and dye loss from the cells were measured with preloaded fura-2. The ultrasound exposure generated fragmentation or shrinking of the microbubble. Only cells adjacent to the ultrasound-driven microbubble exhibited propidium iodide uptake with simultaneous [Ca(2+)](i) increase and fura-2 dye loss. The amount of PI uptake was correlated with the amount of fura-2 dye loss. Cells with delayed [Ca(2+)](i) transients from the time of ultrasound application had no uptake of PI. These results indicate the formation of non-specific pores in the cell membrane by ultrasound-stimulated microbubbles and the generation of calcium waves in surrounding cells without pores.

Dampness in dorm rooms and its associations with allergy and airways infections among college students in China: a cross-sectional study

A cross-sectional study was carried out at Tianjin University campus, China, from February 21 to June 10, 2006, to survey the association between dampness in dorms, and allergy and airways infections among college students. The health and dampness conditions were self-reported by 3436 students living in 1511 dorm rooms located in 13 buildings on the campus. The buildings were selected according to their positions, construction periods and occupant densities. The symptoms involved wheezing, dry cough during night, rhinitis, eczema, cold/flu, ear inflammation, pneumonia and tuberculosis. The indoor moisture signs were mould/damp spots on walls, ceilings and floors; suspected or ever happened water damage; condensation on windowpane in winter and odours perceived by subjects themselves. There was a significant positive association between condensation and dry cough. Eczema was often reported in rooms with moisture problem. Dampness was a significant risk factor for common cold.

PRACTICAL IMPLICATIONS

Dampness problems in dorms of Chinese students are a risk factor for allergic symptoms, and hence there is a need for dorm environment improvement. Health problems related to ventilation and microbiology problems in dorms should be further studied.

Granzyme F induces a novel death pathway characterized by Bid-independent cytochrome c release without caspase activation

Granzyme F (GzmF) belongs to a unique group of granzymes in mice. Murine GzmF is highly expressed in NK3.1 cells and in lymphokine-activated killer (LAK) cells. However, the manner in which GzmF works in granule-mediated cytolysis is unknown. In this study, we first demonstrated that GzmF causes a novel cell death pathway. The death is characterized by an externalization of phosphatidylserine, by nuclear condensation, mitochondrial damage, cytochrome c (cyt c) release, caspase inactivation and single-stranded DNA nicking. GzmF-induced chromatin was incompletely condensed and segmented at the nuclear periphery. Cellular organelles were damaged and the cytoplasm showed an extensive vacuolization that is reminiscent of necroptosis. GzmF can cause rapid mitochondrial swelling, depolarization and reactive oxygen species accumulation. GzmF-induced death does not involve caspase activation, Bid cleavage or activation of DNA nickase NM23H1. GzmF-silenced LAK cells showed reduced cytotoxicity against caspase-inhibited target tumor cells. Moreover, cyt c release is independent of Bid or Bax/Bak. We further showed that GzmF impairs mitochondrial electron transport to abolish ATP generation. ATP decline may contribute to a failure of apoptosome formation, leading to caspase inactivation.

Case mix, quality and high-cost kidney transplant patients

A better understanding of high-cost kidney transplant patients would be useful for informing value-based purchasing strategies by payers. This retrospective cohort study was based on the Medicare Provider Analysis and Review (MEDPAR) files from 2003 to 2006. The focus of this analysis was high-cost kidney transplant patients (patients that qualified for Medicare outlier payments and 30-day readmission payments). Using regression techniques, we explored relationships between high-cost kidney transplant patients, center-specific case mix, and center quality. Among 43 393 kidney transplants in Medicare recipients, 35.2% were categorized as high-cost patients. These payments represented 20% of total Medicare payments for kidney transplantation and exceeded $200 million over the study period. Case mix was associated with these payments and was an important factor underlying variation in hospital payments high-cost patients. Hospital quality was also a strong determinant of future Medicare payments for high-cost patients. Compared to high-quality centers, low-quality centers cost Medicare an additional $1185 per kidney transplant. Payments for high-cost patients represent a significant proportion of the total costs of kidney transplant surgical care. Quality improvement may be an important strategy for reducing the costs of kidney transplantation.

Superparamagnetic iron oxide nanoparticle-labeled cells as an effective vehicle for tracking the GFP gene marker using magnetic resonance imaging

BACKGROUND

Detection of a gene using magnetic resonance imaging (MRI) is hindered by the magnetic resonance (MR) targeting gene technique. Therefore it may be advantageous to image gene-expressing cells labeled with superparamagnetic iron oxide (SPIO) nanoparticles by MRI.

METHODS

The GFP-R3230Ac (GFP) cell line was incubated for 24 h using SPIO nanoparticles at a concentration of 20 microg Fe/mL. Cell samples were prepared for iron content analysis and cell function evaluation. The labeled cells were imaged using fluorescent microscopy and MRI.

RESULTS

SPIO was used to label GFP cells effectively, with no effects on cell function and GFP expression. Iron-loaded GFP cells were successfully imaged with both fluorescent microscopy and T2*-weighted MRI. Prussian blue staining showed intracellular iron accumulation in the cells. All cells were labeled (100% labeling efficiency). The average iron content per cell was 4.75+/-0.11 pg Fe/cell (P<0.05 versus control).

DISCUSSION

This study demonstrates that the GFP expression of cells is not altered by the SPIO labeling process. SPIO-labeled GFP cells can be visualized by MRI; therefore, GFP, a gene marker, was tracked indirectly with the SPIO-loaded cells using MRI. The technique holds promise for monitoring the temporal and spatial migration of cells with a gene marker and enhancing the understanding of cell- and gene-based therapeutic strategies.

Dampness at dorm and its associations with allergy and airways infection among college students in China: a cross-sectional study

A cross-sectional study was carried out at Tianjin University campus, China, from February 21 to June10, 2006, to survey the association between dampness in dorms and allergy and airways infection among college students. The health and dampness condition were self-reported by 3436 students living in 1511 dorm rooms located in 13 buildings on the campus. The buildings were selected according to their positions, construction periods and occupant densities. The allergy and airways infection symptoms involved wheezing, dry cough during night, rhinitis, eczema, cold/flu, ear inflammation, pneumonia and tuberculosis. The indoor moisture signs were mould/damp spots on walls, ceilings and floors; suspected or ever happened water damage; condensation on windowpane in winter and odours perceived by subjects themselves. This study showed there was significantly positive association between condensation and dry cough. Eczema was often reported in rooms with suspected moisture problem. Dampness was a significantly risk factor for common cold.

PRACTICAL IMPLICATIONS

This paper indicated that dampness problem at dorms of Chinese students was a risk factor in irritating allergic symptoms, and hence there is a need for dorm environment improvement. The ventilation and microbiology problems in dorm environment corresponding to dampness should be further studied, especially when it is associated to occupants' health.

Expression of ER-a36, a novel variant of estrogen receptor a, and resistance to tamoxifen treatment in breast cancer

Abstract #3037

Background: Recently, a 36 kDa variant of estrogen receptor a (ER-a66), ER-a36, has been identified and cloned. ER-a36 predominantly localizes on the plasma membrane and in the cytoplasm and mediates a membrane-initiated “nongenomic” signaling pathway. In this study, we investigated the association between ER-a36 expression and tamoxifen resistance in breast cancer patients.&#x2028; Methods: ER-a36 protein expression in tumors from 710 breast cancer patients with a median follow-up of 7.9 years was assessed using immunohistochemistry (IHC) assay. Survival curves were compared using the log-rank test and multivariate analysis was performed using Cox model. All statistical tests were two-sided.&#x2028; Results: Among the patients with ER-a66 positive tumors who received tamoxifen treatment (n=307), overexpression of ER-a36 was associated with poorer disease-free survival (DFS) and disease-specific survival (DSS) and remained as an unfavorable independent factor of survival in multivariate analyses (DFS: HR=2.27; 95% CI= 1.40 to 3.68; P=. 001; DSS: HR=2.42; 95% CI= 1.37 to 4.28; P= .002). In contrast, among patients with ER-a66 positive tumors who did not receive tamoxifen (n=129), ER-a36 expression was not associated with survival, indicating a correlation between ER-a36 expression and tamoxifen resistance. Furthermore, ER-a36 expression was not associated with survival in ER-a66 negative tumors whether the patients received tamoxifen (n=73) or not (n=149). Our in vitro experiments with MCF7/ER36 cells also confirmed that high ER-a36 expression resulted in tamoxifen resistance.&#x2028; Conclusions: Patients with ER-a66 positive tumors that also express high levels of ER-a36 are less likely to benefit from tamoxifen treatment. ER-a36 is an important predictive marker for tamoxifen therapy in ER-a66 positive breast cancer patients.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3037.

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.