[Atopic keratoconjunctivitis: One allergy may mask another. A clinical observation with two types of hypersensitivity reactions: IgE-mediated and non-IgE-mediated]

Allergies are frequently implicated in ophthalmologic practice. These typically benign allergies can be potentially severe for the ocular surface and have an impact in everyday life. We relate, through a case of keratoconjunctivitis involving 2 types of hypersensitivity, the various triggers and therapeutic choices to allow a more effective treatment.

[Progression of nerve fiber layer defects in retrobulbar optic neuritis by the macular ganglion cell complex]

INTRODUCTION

Recent studies with SD OCT had shown early axonal damage to the macular ganglion cell complex (which consists of the three innermost layers of the retina: Inner Plexiform Layer [IPL], Ganglion Cell Layer [GCL], Retinal Nerve Fibre layer [RNFL]) in optic nerve pathology. Retrobulbar optic neuritis (RBON), occurring frequently in demyelinating diseases, leads to atrophy of the optic nerve fibers at the level of the ganglion cell axons, previously described in the literature. The goal of this study is to evaluate the progression of optic nerve fiber defects and macular ganglion cell complex defects with the SPECTRALIS OCT via a reproducible method by calculating a mean thickness in each quadrant after an episode of retrobulbar optic neuritis.

METHODS

This is a prospective monocentric observational study including 8 patients at the Clermont-Ferrand university medical center. All patients underwent ocular examination with macular and disc OCT analysis and a Goldmann visual field at the time of inclusion (onset or recurrence of RBON), at 3 months and at 6 months.

RESULTS

Patients were 40-years-old on average at the time of inclusion. After 6 months of follow-up, there was progression of the atrophy of the macular ganglion cell complex in the affected eye on (11.5% or 11μm) predominantly inferonasally (13.9% or 16μm) and superonasally (12.9% or 14μm) while the other eye remained stable. The decrease in thickness occurred mainly in the most internal 3 layers of the retina. On average, the loss in thickness of the peripapillary RNFL was predominantly inferotemporal (24.9% or 39μm) and superotemporal (21.8% or 28μm).

DISCUSSION

In 3 months of progression, the loss of optic nerve fibers is already seen on macular and disc OCT after an episode of RBON, especially in inferior quadrants in spite of the improvement in the Goldmann visual field and visual acuity. Segmentation by quadrant was used here to compare the progression of the defect by region compared to the fovea in a global and reproducible way. The loss of thickness, predominantly inferonasally and superonasally, appears to correspond to the temporal loss on optic nerve OCT according to the literature.

CONCLUSION

The follow-up of these patients with retrobulbar neuritis is important as shown by the possibility of relapse, especially in multiple sclerosis. Monitoring of the macular ganglion cell complex by a global method of calculation could contribute to the detection and localization of early damage after an episode of retrobulbar neuritis. This could possibly lead to a discussion of treatment modification or increased surveillance in cases of early detection of nerve fiber atrophy, or to showing the importance of monitoring, since monitoring of RBON is not standardized.

Geographic and socioeconomic factors affecting delivery of bariatric surgery across high- and low-utilization healthcare systems

Background

In countries with universal health coverage, the delivery of care should be driven by need. However, other factors, such as proximity to local facilities or neighbourhood socioeconomic status, may be more important. The objective of this study was to evaluate which geographic and socioeconomic factors affect the delivery of bariatric care in Canada.

Methods

This was a national retrospective cohort study of all adult patients undergoing bariatric surgery between April 2008 and March 2015 in Canada (excluding Quebec). The main outcome was neighbourhood rate of bariatric surgery per 1000 obese individuals (BMI over 30 kg/m2). Geographic cluster analysis and multilevel ordinal logistic regression were used to identify high-use clusters, and to evaluate the effect of geographic and socioeconomic factors on care delivery.

Results

Having a bariatric facility within the same public health unit as the neighbourhood was associated with a 6·6 times higher odds of being in a bariatric high-use cluster (odds ratio (OR) 6·60, 95 per cent c.i. 1·90 to 22·88; P = 0·003). This finding was consistent across provinces after adjusting for utilization rates. Neighbourhoods with higher obesity rates were also more likely to be within high-use clusters (OR per 5 per cent increase: 2·95, 1·54 to 5·66; P = 0·001), whereas neighbourhoods closer to bariatric centres were less likely to be (OR per 50 km: 0·91, 0·82 to 1·00; P = 0·048).

Conclusion

In this study, across provincial healthcare systems with high and low utilization, the delivery of care was driven by the presence of local facilities and neighbourhood obesity rates. Increasing distance to bariatric centres substantially influenced care delivery.

Renal cell carcinoma escapes death by p53 depletion through transglutaminase 2-chaperoned autophagy

In renal cell carcinoma, transglutaminase 2 (TGase 2) crosslinks p53 in autophagosomes, resulting in p53 depletion and the tumor's evasion of apoptosis. Inhibition of TGase 2 stabilizes p53 and induces tumor cells to enter apoptosis. This study explored the mechanism of TGase 2-dependent p53 degradation. We found that TGase 2 competes with human double minute 2 homolog (HDM2) for binding to p53; promotes autophagy-dependent p53 degradation in renal cell carcinoma (RCC) cell lines under starvation; and binds to p53 and p62 simultaneously without ubiquitin-dependent recognition of p62. The bound complex does not have crosslinking activity. A binding assay using a series of deletion mutants of p62, p53 and TGase 2 revealed that the PB1 (Phox and Bem1p-1) domain of p62 (residues 85-110) directly interacts with the β-barrel domains of TGase 2 (residues 592-687), whereas the HDM2-binding domain (transactivation domain, residues 15-26) of p53 interacts with the N terminus of TGase 2 (residues 1-139). In addition to the increase in p53 stability due to TGase 2 inhibition, the administration of a DNA-damaging anti-cancer drug such as doxorubicin-induced apoptosis in RCC cell lines and synergistically reduced tumor volume in a xenograft model. Combination therapy with a TGase 2 inhibitor and a DNA-damaging agent may represent an effective therapeutic approach for treating RCC.

Abstract P3-14-02: Targeting the PI3K/AKT/mTOR pathway for the treatment of mesenchymal triple-negative breast cancer (TNBC): Evidence of efficacy and proof of concept from a phase I trial with dose expansion of mTOR inhibition in combination with liposomal doxorubicin and bevacizumab

Background: Approximately 30% of TNBCs are characterized by microarray as claudin-low, mesenchymal or mesenchymal stem cell-like and, unlike basal TNBCs, these tumors frequently harbor aberrations in the PI3K/AKT/mTOR axis, raising the possibility of targeting this axis to enhance chemotherapy response. Assays to clinically identify mesenchymal TNBCs are under development, but published results confirm that up to 30% are metaplastic breast cancers (MpBCs), a chemo-refractory group of tumors that contain a mixture of epithelial and mesenchymal components, making them identifiable by microscopy. As such, MpBCs serve as surrogates of response for potential regimens to treat mesenchymal TNBC.

Methods: Patients (pts) with advanced TNBC (N=64) were treated with liposomal doxorubicin (D), bevacizumab (A) and the mTOR inhibitors temsirolimus (T) or everolimus (E). D and A were administered IV on day 1 with T (IV on days 1, 8 and 15) or E (continuous daily oral administration) using 21 day cycles. Response was assessed every 6 weeks using RECIST. When available, archived tissue was evaluated for aberrations in the PI3K pathway using standard assays.

Results: Fifty-two MpBC pts were treated with DAT (N=39) or DAE (N=13). Median age was 58 (range 37-79); median # of prior regimens for metastatic disease was 1 (range 0-5). The objective response rate (ORR) was 21% [complete response (CR)=4 (8%); partial response (PR)=7 (13%)] and 10 (19%) pts had stable disease (SD)≥6 months for a clinical benefit rate (CBR) of 40%. Tissue was available for testing in 43 pts and 32 (74%) had a PI3K pathway activating aberration (Table 1).

Response According to PI3K Pathway AberrationPI3K Pathway AberrationN (%)CRPRSD≥6monthsCBRORRAny PI3K Pathway Aberration*32 (74)46444%31%PIK3CA Mutation19 (59)23447%26%p.H1047R12 (38)21350%25%p.E545K6 (19)02150%33%p.G1007R1 (3)010100%100%p.E545A1 (3)0000%0%p.H1047Y1 (3)0000%0%p.K111E1 (3)0000%0%p.E542K1 (3)0000%0%PIK3CA Amplification1 (3)010100%100%PTEN Mutation5 (16)0000%0%PTEN Loss5 (16)02040%40%AKT1 p.E17K Mutation2 (6)0000%0%AKT2 Amplification1 (3)100100%100%PIK3R1 Mutation2 (6)01050%50%NF2 Mutation1 (3)100100%100%No PI3K Pathway Aberration11 (26)00545%0%*Some tumors had >1 aberration detected

PI3K pathway activation was associated with a significant improvement in ORR (31 vs 0%; P=0.043) but not CBR (44 vs 45%; P=1.000) or progression-free survival (median 5.1 vs 2.9 months; P=0.352). A pt with 5 year+ durable CR (on maintenance everolimus) had a mutation in NF2. To emphasize the importance of pt selection, it is notable that 12 pts with non-metaplastic TNBC were also treated with DAT, and only 1 pt had a response (CR/PR=1; SD≥6 months=0), for a CBR that was significantly worse than pts with MpBC (8 vs 40%; P=0.045).

Conclusions: Using MpBC as a surrogate of response, DAT/DAE has significantly better activity in mesenchymal compared to non-selected TNBC. Response is enhanced in pts with PI3K pathway activation. DAT/DAE should be tested in non-metaplastic, mesenchymal TNBC once a diagnostic assay is available.

Citation Format: Basho RK, Gilcrease M, Murthy RK, Helgason T, Booser DJ, Karp DD, Meric-Bernstam F, Wheler JJ, Valero V, Albarracin C, Litton J, Chavez-MacGregor M, Ibrahim NK, Murray JL, Koenig KB, Hong D, Subbiah V, Kurzrock R, Janku F, Moulder S. Targeting the PI3K/AKT/mTOR pathway for the treatment of mesenchymal triple-negative breast cancer (TNBC): Evidence of efficacy and proof of concept from a phase I trial with dose expansion of mTOR inhibition in combination with liposomal doxorubicin and bevacizumab. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-14-02.

Cytokine profile and prognostic significance of high neutrophil-lymphocyte ratio in colorectal cancer

Background:

High circulating neutrophil-lymphocyte ratio (NLR) appears to be prognostic in metastatic colorectal cancer (mCRC). We investigated the relationship of NLR with circulating cytokines and molecular alterations.

Methods:

We performed retrospective analyses on multiple cohorts of CRC patients (metastatic untreated (n=166), refractory metastatic (n=161), hepatectomy (n=198), stage 2/3 (n=274), and molecularly screened (n=342)). High NLR (ratio of absolute neutrophil-to-lymphocyte counts in peripheral blood) was defined as NLR>5. Plasma cytokines were evaluated using multiplex-bead assays. Kaplan–Meier estimates, non-parametric correlation analysis, and hierarchical cluster analyses were used.

Results:

High NLR was associated with poor prognosis in mCRC (hazard ratio (HR) 1.73; 95% confidence interval (CI):1.03–2.89; P=0.039) independent of known prognostic factors and molecular alterations (KRAS/NRAS/BRAF/PIK3CA/CIMP). High NLR correlated with increased expression of interleukin 6 (IL-6), IL-8, IL-2Rα, hepatocyte growth factor, macrophage-colony stimulating factor, and vascular epidermal growth factor in exploratory (n=39) and validation (n=166) cohorts. Fourteen additional cytokines correlated with high NLR in the validation cohort. All 20 cytokines fell into three major clusters: inflammatory cytokines, angiogenic cytokines, and epidermal growth factor ligands. In mCRC, composite stratification based on NLR-cytokine score provided enhanced prognostic information (HR 2.09; 95% CI: 1.59–2.76; P<0.001) over and above NLR.

Conclusions:

High NLR is an independent poor prognostic marker in CRC and correlates with a distinct cytokine profile related to key biological processes involved in carcinogenesis. A composite NLR-cytokine stratification has enhanced prognostic value in mCRC.

Phase I study of pazopanib and vorinostat: a therapeutic approach for inhibiting mutant p53-mediated angiogenesis and facilitating mutant p53 degradation

BACKGROUND

We carried out a phase I trial of the vascular endothelial growth factor inhibitor pazopanib and the histone deacetylase inhibitor vorinostat to determine the safety and efficacy. Because these agents are known to target factors activated by TP53 mutation and facilitate mutant p53 degradation, a subgroup analysis may be interesting in patients with TP53 mutant malignancies.

PATIENTS AND METHODS

Patients with advanced solid tumors (n = 78) were enrolled following a 3 + 3 design, with dose expansion for those with responsive tumors. Hotspot TP53 mutations were tested when tumor specimens were available.

RESULTS

Adverse events of ≥grade 3 included thrombocytopenia, neutropenia, fatigue, hypertension, diarrhea and vomiting. Overall, the treatment produced stable disease for at least 6 months or partial response (SD ≥6 months/PR) in 19% of the patients, median progression-free survival (PFS) of 2.2 months, and median overall survival (OS) of 8.9 months. In patients with detected hotspot TP53 mutant advanced solid tumors (n = 11), the treatment led to a 45% rate of SD ≥6 months/PR (1 PR and 3 SD ≥6 months), median PFS of 3.5 months, and median OS of 12.7 months, compared favorably with the results for patients with undetected hotspot TP53 mutations (n = 25): 16% (1 PR and 3 SD ≥6 months, P = 0.096), 2.0 months (P = 0.042), and 7.4 months (P = 0.1), respectively.

CONCLUSION

The recommended phase II dosage was oral pazopanib at 600 mg daily plus oral vorinostat at 300 mg daily. The preliminary evidence supports further evaluation of the combination in cancer patients with mutated TP53, especially in those with metastatic sarcoma or metastatic colorectal cancer.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov, NCT01339871.

The prognostic significance of left ventricular ejection fraction in patients with advanced cancer treated in phase I clinical trials

BACKGROUND

New targeted agents may cause acute cardiac events. The purpose of our study was to investigate the incidence and the prognostic significance of left ventricular ejection fraction (LVEF) in phase I trials.

PATIENTS AND METHODS

Between October 2008 and September 2011, the records of 1166 consecutive patients with advanced cancer treated in the Phase I Clinic who underwent echocardiography were retrospectively reviewed.

RESULTS

Most of the patients were White (78%), and the most common tumor types were colorectal cancer and melanoma. Of 1166 patients, 177 (15.2%) patients had an LVEF of <50%. No difference in overall survival (OS) between patients with LVEF ≥ 50% and patients with LVEF < 50% was seen (median OS 7.4 versus 7.0 months, P = 0.84). Patients with LVEF ≤ 35% had shorter survival compared with those with LVEF between 35% and 50% (median 4.2 versus 8.0 months; P = 0.005). In multivariate analysis of patients with LVEF < 50%, independent factors predicting longer survival were LVEF > 35%, ≤2 prior systemic therapies, ≤2 metastatic sites, and normal lactate dehydrogenase and albumin levels.

CONCLUSION

Echocardiography would improve patient selection for enrollment in phase I clinical trials. These data suggest that it is safe to treat patients with LVEF between 35% and 50%.

PATHOME: an algorithm for accurately detecting differentially expressed subpathways

The translation of high-throughput gene expression data into biologically meaningful information remains a bottleneck. We developed a novel computational algorithm, PATHOME, for detecting differentially expressed biological pathways. This algorithm employs straightforward statistical tests to evaluate the significance of differential expression patterns along subpathways. Applying it to gene expression data sets of gastric cancer (GC), we compared its performance with those of other leading programs. Based on a literature-driven reference set, PATHOME showed greater consistency in identifying known cancer-related pathways. For the WNT pathway uniquely identified by PATHOME, we validated its involvement in gastric carcinogenesis through experimental perturbation of both cell lines and animal models. We identified HNF4α-WNT5A regulation in the cross-talk between the AMPK metabolic pathway and the WNT signaling pathway, and further identified WNT5A as a potential therapeutic target for GC. We have demonstrated PATHOME to be a powerful tool, with improved sensitivity for identifying disease-related dysregulated pathways.

A simple novel endoscopic successive suture device: a validation study for closure strength and reproducibility

BACKGROUND AND STUDY AIMS

Endoscopic surgical technology has been developing rapidly. Although several successful endoscopic closure devices have already been introduced, only a few of them have demonstrated improvements in closure strength and reproducibility over conventional endoscopic clip closures or hand sutures. The objective of this study was to test the feasibility of a novel successive suturing device (SSD) by measuring closure strength and reproducibility.

MATERIAL AND METHODS

Porcine stomach models were used in this study. Endoclips, full-thickness hand sutures, and the novel SSD sutures were used to close a perforation in the stomach wall, with 10 stomachs being tested for each closure method. Endoclips and SSD sutures were performed using a two-channel endoscope, and the hand sutures were performed from outside of the stomach wall. Air leakage pressure was measured to determine the closure strength and reproducibility of each method.

RESULTS

The mean air leakage pressure of the SSD closure was 62.7 ± 8.2 mmHg. SSD-treated stomachs exhibited significantly greater air leakage pressure than Endoclip-treated stomachs. The standard deviation of bursting pressure in SSD stomachs was found to be significantly smaller than that of hand-sewn stomachs but was not different from that of Endoclip stomachs.

CONCLUSIONS

The consistent closure strength of SSD stomachs demonstrated the reliability and reproducibility of this new closure method. These promising results in closure strength and reproducibility suggest the feasibility of the proposed device for clinical applications.

Tumor marker and measurement fluctuations may not reflect treatment efficacy in patients with medullary thyroid carcinoma on long-term RET inhibitor therapy

BACKGROUND

RET kinase inhibitors have significant activity in patients with medullary thyroid carcinoma (MTC).

PATIENTS AND METHODS

We retrospectively reviewed the electronic medical record for patterns of calcitonin, carcinoembryonic antigen (CEA) and tumor measurement responses in consecutive patients with MTC who received treatment with a RET inhibitor for at least 6 months.

RESULTS

Twenty-six patients who received RET kinase inhibitors for at least 6 months were included. All patients experienced an initial decline in calcitonin; 20 (77%) demonstrated later fluctuations in calcitonin, which spiked above baseline levels in 9 individuals (35%). Twenty of the 22 patients (91%) with elevated CEA experienced a decline with treatment, with 11 individuals (50%) later demonstrating transient fluctuations in CEA, including spikes above baseline in 7 patients (32%). Ten of the 26 patients (38%) also demonstrated short-lived fluctuations in RECIST measurements, including changes of over 20% from nadir values. Vacillations in calcitonin, CEA and measurements often occurred repeatedly in individual patients and did not regularly correlate with each other.

CONCLUSIONS

Repeated transient fluctuations in tumor markers and measurements are a characteristic of patients with MTC receiving treatment with RET inhibitors, and such short-term vacillations may not reflect responsiveness over the long term.

CLINICAL TRIALS INCLUDED

NCT00215605; NCT00244972; NCT00121680; NCT00495872.

Abstract P5-20-09: Tumor mutational analysis and therapy outcomes for patients (pts) with metastatic/unresectable locally advanced myoepithelial/metaplastic breast cancer treated with PI3K targeted therapy

Background: Metaplastic breast cancers are considered a chemorefractory subset of triple negative breast cancers. Molecular profiling has demonstrated that metaplastic tumors are enriched for epithelial-to-mesenchymal transition (EMT), frequently express myoepithelial differentiation, make up a component of the ‘claudin-low’ subtype, and harbor relatively high rates of mutations/activation of the PI3kinase pathway (Hennessy, Cancer Research, 2009; Prat, Breast Cancer Res, 2010).

Methods: Data from pts with myoepithelial/metaplastic breast cancer treated within the Center for Targeted Therapy using regimens with known inhibitors of the PI3K pathway were evaluated to determine response to therapy. Mutational analyses were performed in archived tumor samples when available.

Results: 23 pts have been treated using 6 different therapy regimens and one pt was treated on two separate clinical trials for a total of 24 analyzable outcomes. Patients were treated with liposomal doxorubicin, bevacizumab and the mTOR inhibitor, temsirolimus (DAT, n=17); liposomal doxorubicin and temsirolimus (DT, n=1); paclitaxel, bevacizumab and temsirolimus (TAT, n=3); paclitaxel and temsirolimus (TT, n=1), paclitaxel in combination with an experimental PI3K inhibitor (TEx, n=1), or temsirolimus alone (tem, n=1). Response was measured every two cycles using RECIST criteria. Most pts had received prior chemotherapy, median of 2 prior regimens (range 0–7). Three patients were not evaluated for response, one who died of pneumonia during cycle 2 (DAT) and two who have not yet completed 2 cycles of therapy (DAT, TEx). Response rate (CR+PR) was 35% (CR = 2, PR=4, SD≥6 months=2, SD&lt;6 months=2, PD/death=7) with the anthracycline based regimens, DAT and DT; whereas, stable disease was the best response seen thus far with the paclitaxel based regimens or temsirolimus alone: TAT (SD&lt;6months=2, PD=1), TT (SD&lt;6months=1), tem (SD&lt;6months=1). 8 of 9 tumors tested (89%) were found to have mutations that would lead to activation of the PI3K pathway: PIK3CA=5 (62%), PTEN=2 (25%) and NF2=1(13%). The two patients with CR from DAT had mutations in NF2 and PIK3CA, respectively. Both patients remain in CR (2+ years and 1+ year respectively) after discontinuing protocol therapy, and both continue maintenance everolimus.

Conclusion: Activating mutations in the PI3K pathway are common in metaplastic breast cancers, a tumor subtype that shares molecular features with claudin-low and mesenchymal/mesenchymal-stem cell like triple negative breast cancers. DAT has demonstrated activity in myoepithelial/metaplastic breast cancer including two durable CRs to therapy. This regimen should be explored in larger, randomized trials to test superiority to chemotherapy alone.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-20-09.

Parallel, self-organizing, hierarchical neural networks

A new neural-network architecture called the parallel, self-organizing, hierarchical neural network (PSHNN) is presented. The new architecture involves a number of stages in which each stage can be a particular neural network (SNN). At the end of each stage, error detection is carried out, and a number of input vectors are rejected. Between two stages there is a nonlinear transformation of input vectors rejected by the previous stage. The new architecture has many desirable properties, such as optimized system complexity (in the sense of minimized self-organizing number of stages), high classification accuracy, minimized learning and recall times, and truly parallel architectures in which all stages operate simultaneously without waiting for data from other stages during testing. The experiments performed indicated the superiority of the new architecture over multilayered networks with back-propagation training.

Heterogeneous cytoplasmic calcium response in microvascular endothelial cells

We investigated changes in calcium concentration in response to the administration of ATP and the onset of shear stress with cultured rat adrenomedulary endothelial cells (RAMECs, microvascular). A substantial heterogeneity in time and space in the calcium response was observed. The onset of shear stress induced calcium waves that originated from one or several cells and propagated to neighboring cells The application of uniform exogenous ATP produced similar heterogeneous calcium transients. The size of the responding groups was dependent on ATP concentration. The propagation of calcium waves induced by either ATP or shear stress challenge was significantly suppressed by suramin, a non-specific purinergic receptor blocker. We investigated some of the mechanisms leading to the heterogeneity, and the results indicated that the main source of variation is the heterogeneous distribution of purinergic receptor. The application of ATP or shear stress stimulates cells to release ATP causing an increase of [Ca²⁺]<inf>i</inf>via purinergic receptor in the cells that have high sensitivity. Subsequently, additional ATP is released and the elevation of ATP concentration in the vicinity of the initially responding cells mediates the calcium propagation. These data suggest a mechanism by which ATP acts as an autocrine and paracrine mediator to integrate individual cell responses that result in coordination of vascular functions in situ.

Isolation and characterization of five rice telomere-associated sequences

Acoording to the telomere-repeated sequences of rice, two primers: (TTTAGGG11)(3) and (CCC-TAA.A)(3)CCC were used to amplify rice telomere-assciated sequences (TASs). Fox PCR template preparation. total DNA was digested with restrictive endonuclease and then ligated. Using the ligates or total DNA sa template, eight fragments were obtained with the single primer by the PCR reaction. To confirm that the sequences are derived from telomeric DNA, we conducted Bal31 digestion analysis. Of the eight fragments, seven were susceptible to Bal31 treatment, suggesting that they were TASs. These DNA fragments were further demonstrated u, be rice sub-telomeric sequences by RFLP mapping Five sequences have been mapped to the distal ends on rice chromme 5,6,7 and 9, and two other sequences have been mapped at interstitial sites, suggesting that (TTTAGGG)(n). also exist in the middle of rice chromosomes-All eight fragments were sequenced and characterized.

Quantitative proteomic analysis of dexamethasone-induced effects on osteoblast differentiation, proliferation, and apoptosis in MC3T3-E1 cells using SILAC

SUMMARY

The impairment of osteoblast differentiation is one cause of the glucocorticoid-induced osteoporosis (GCOP). The quantitative proteomic analysis of the dexamethasone (DEX)-induced effects of osteoblast differentiation, proliferation, and apoptosis using stable-isotope labeling by amino acids in cell culture (SILAC) demonstrated drastic changes of some key proteins in MC3T3-E1 cells.

INTRODUCTION

The impairment of osteoblast differentiation is one of the main explanations of GCOP. SILAC enables accurate quantitative proteomic analysis of protein changes in cells to explore the underlying mechanism of GCOP.

METHODS

Osteoprogenitor MC3T3-E1 cells were treated with or without 10(−6) M DEX for 7 days, and the differentiation ability, proliferation, and apoptosis of the cells were measured. The protein level changes were analyzed using SILAC and liquid chromatography-coupled tandem mass spectrometry.

RESULTS

In this study, 10(−6) M DEX inhibited both osteoblast differentiation and proliferation but induced apoptosis in osteoprogenitor MC3T3-E1 cells on day 7. We found that 10(−6) M DEX increased the levels of tubulins (TUBA1A, TUBB2B, and TUBB5), IQGAP1, S100 proteins (S100A11, S100A6, S100A4, and S100A10), myosin proteins (MYH9 and MYH11), and apoptosis and stress proteins, while inhibited the protein levels of ATP synthases (ATP5O, ATP5H, ATP5A1, and ATP5F1), G3BP-1, and Ras-related proteins (Rab-1A, Rab-2A, and Rab-7) in MC3T3-E1 cells.

CONCLUSIONS

Several members of the ATP synthases, myosin proteins, small GTPase superfamily, and S100 proteins may participate in functional inhibition of osteoblast progenitor cells by GCs. Such protein expression changes may be of pathological significance in coping with GCOP.