P3-03-02: Higher Expression Levels of Circulating miR-21, miR-19a and miR-10b Are Associated with High Risk Features in Breast Cancer

Background: MicroRNAs (miRs) have oncogenic and tumor-suppressor functions. MiR-21, miR-19a and miR-10b are overexpressed in breast cancer and regulate tumor cell migration, invasion and angiogenesis. We assessed the levels of miR-21, -19a, and -10b in sera of breast cancer patients and their association with the stage, histological type, hormonal receptor (HR) status and HER2 amplification in the primary tumor. Since circulating tumor cells (CTC) detected by CellSearch® are an independent and strong predictor of overall survival in metastatic breast cancer (MBC), we assessed the relationship between circulating miRs and CTCs.

Methods: The study consisted of 30 healthy donors (HD) and 95 breast cancer (BC) patients. Patients’ sera were collected before starting a new line of treatment. Total RNA was isolated, reverse transcribed to cDNA and then subjected to qRT-PCR for the detection of miR-21, -19a, -10b and -192 using the TaqMan MicroRNA Assay (Applied Biosystems, Foster City, CA). Mir-192 was used to normalize the expression levels of the other miRs. Fold-changes in expression of miRs were calculated using the 2−DCt method, where DCt= mean CTtarget-miRNA -mean CTmiR-192. CTCs were enumerated using CellSearch™ (Veridex LLC, Warren, NJ). Mann-Whitney U test was used to determine differences in serum miR expression levels between patients and HD.

Results: Of the 95 BC patients, 39 were non-MBC and 56 MBC. Patients grouped according to the receptor expression by immunohistochemical staining consisted of 27 HR+HER2−, 30 HR+HER2+, 20 HRHER2+, and 18 HRHER2− triple negative BC (TNBC). MiR-21 and miR-19a were higher in non-MBC patients than in HD (p=.001, p<.001, respectively). MiR-21, miR-19a and miR-10b levels were higher in metastatic patients than in HD (p<.001, p<.001, p=.038, respectively). MBC patients had a higher median level of miR-21 than that of non-MBC patients (p=.02). Patients with (HR+HER2+, HR−HER2+, TNBC) had significantly higher median levels of both miR-21 (p=.018; p=.009; p=.045) and miR-10b (p=.011; p=.014; p=.03) compared with HR+HER2− BC. HER2+ patients had higher median levels of both miR-21 and miR-10b than those of HER2− BC (p=.033; p=.01) and HD (p<.001; p=.009). Further, median miR-19a expression was higher in IBC patients than in non-IBC patients (p=.025). Finally, patients with <5 CTCs had a higher median expression level of miR-10b than that of patients with ≥5 CTCs (p=.042).

Discussion: High expression levels of miR-21, miR-19a and miR-10b in sera are observed in breast cancer patients, especially with advanced disease. HER2+ BC patients had higher serum levels of miR-21 and miR-10b than HER2−. IBC patients had a higher serum level of miR-19a than non-IBC patients. Moreover, patients with <5 CTCs had high serum levels of miR-10b that can be induced by Twist1 during the epithelial-mesenchymal transition (EMT) and, in part, explain the inability of CellSearch® to detect CTCs undergoing EMT.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-03-02.

P4-20-03: T-Cell Cytokine Production Related to Progression of Breast Cancer Patients

Background: Impaired immunosurveillance and immune dysregulation contribute to the pathogenesis and progression of breast cancer (BC). Upon activation, T cells synthesize inflammatory cytokines such as TNF-α that can promote or inhibit tumor growth. We therefore investigated T-cell cytokine syntheses as a predictor of disease progression.

Methods: We recruited 115 BC patients [25 with locally advanced breast cancer (LABC), 21 with metastatic breast cancer (MBC), 25 with non-metastatic inflammatory breast cancer (IBC), and 44 with metastatic IBC (mIBC)] and 31 healthy donors (HD) for this ongoing study. The tumor phenotype consisted of 69 hormone receptor (HR) positive (including 26 patients with HER2 positive disease), 16 HR negative but HER2+, 30 triple negative BC (TNBC). To evaluate T cell function, peripheral blood mononuclear cells from patients and HD were stimulated overnight with immobilized anti-CD3 and soluble anti-CD28 antibodies and assessed for the percentage of T cells that synthesized cytokines by multi-parameter flow cytometry. The associations of T cell cytokine production profile with patient progression free survival (PFS) were analyzed by Kaplan Meier Test.

Results: The median follow-up (FU) of 113 evaluable patients was 14.1 months with a median time to relapse of 10.5 months; 54 patients had stable disease (SD) and 59 patients had progression of disease (PD). In the entire cohort, on univariate analysis, metastasis, IBC, stage, and previous treatment predicted for worse PFS (p< 0.05). In non-metastatic patients (LABC+IBC), absolute count of anti-CD3 activated CD8+ T cells producing IL-17 was significantly higher in the SD patients compared with patient with PD (p=0.038), but it did not predict PFS (p=0.073). Similarly in metastatic patients, anti-CD3 activated CD4+ T cells producing TNF-α were significantly higher in patients with SD (p=0.025) and was predictive of longer PFS (p=0.033). Considering all patients with IBC (IBC + mIBC), although patients with PD had significantly fewer (percent and absolute number) anti-CD3 activated T cells capable of producing cytokines, this immune impairment was mostly related to metastasis and previous treatment. However, the percentage of anti-CD3 activated CD8+ T cells producing TNF-α was an independent positive prognostic indicator of PFS (p=0.002).

Conclusion: Higher than average cytokine syntheses by anti-CD3 activated T cells are significantly associated with longer PFS. These data are consistent with the hypothesis that an adaptive immune response can control disease progression.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-20-03.

Heading date gene, dth3 controlled late flowering in O. Glaberrima Steud. by down-regulating Ehd1

Heading date in rice is an important agronomic trait controlled by several genes. In this study, flowering time of variety Dianjingyou 1 (DJY1) was earlier than a near-isogenic line (named NIL) carried chromosome segment from African rice on chromosome 3S, when grown in both long-day (LD) and short-day (SD) conditions. By analyzing a large F2 population from NIL × DJY1, the locus DTH3 (QTL for days to heading on chromosome 3) controlling early heading date in DJY1 was fine mapped to a 64-kb segment which contained only one annotated gene, a MIKC-type MADS-box protein. We detected a 6-bp deletion and a single base substitution in the C-domain by sequencing DTH3 in DJY1 compared with dth3 in NIL, and overexpression of DTH3 caused early flowering in callus. Quantitative real-time PCR revealed that the transcript level of dth3 in NIL was lower than that DTH3 in DJY1 in both LD and SD conditions. The Early heading date 1 (Ehd1) which promotes the RFT1, was up-regulated by DTH3 in both LD and SD conditions. Based on Indel and dCAPs marker analysis, the dth3 allele was only present in African rice accessions. A phylogenetic analysis based on microsatellite genotyping suggested that African rice had a close genetic relationship to O. rufipogon and O. latifolia, and was similar to japonica cultivars. DTH3 affected flowering time and had no significant effect on the main agronomic traits.

Correlation of brain natriuretic peptide and microalbuminuria in patients with heart failure

OBJECTIVE

To evaluate the changes of plasma levels of N-terminal pro-brain natriuretic pepide (NT-proBNP) and microalbuminuria (MAU) in patients with heart failure and the correlation between them.

METHODS

Ninety-one patients with heart failure were divided into different groups according to different stages of heart failure. Plasma levels of NT-proBNP were measured by microsome enzyme immunoassay (MEIA). Plasma levels of MAU were determined by immune scattering turbidimetry (ICTM). Simultaneously, left ventricular ejection fraction (LVEF) and left ventricular end diastolic diameter (LVEDD) were measured by Doppler echocardiography for all patients. The correlation of NT-proBNP and MAU was evaluated at different stages of heart failure.

RESULTS

The plasma levels of NT-proBNP and MAU increased with the severity of heart failure. There was a high correlation between NT-proBNP and MAU (r = 0.885, p < 0.001).

CONCLUSION

Both NT-proBNP and MAU levels were closely associated with the severity of heart failure.

Single spin asymmetries in charged pion production from semi-inclusive deep inelastic scattering on a transversely polarized 3He Target at Q2 = 1.4-2.7 GeV2

We report the first measurement of target single spin asymmetries in the semi-inclusive (3)He(e,e'π(±))X reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0.16 < x < 0.35 with 1.4 < Q(2) < 2.7 GeV(2). The Collins and Sivers moments were extracted from the azimuthal angular dependence of the measured asymmetries. The π(±) Collins moments for (3)He are consistent with zero, except for the π(+) moment at x = 0.35, which deviates from zero by 2.3σ. While the π(-) Sivers moments are consistent with zero, the π(+) Sivers moments favor negative values. The neutron results were extracted using the nucleon effective polarization and measured cross section ratios of proton to (3)He, and are largely consistent with the predictions of phenomenological fits and quark model calculations.

A photo-multiplier tube-based hybrid MRI and frequency domain fluorescence tomography system for small animal imaging

Fluorescence tomography (FT) is a promising molecular imaging technique that can spatially resolve both fluorophore concentration and lifetime parameters. However, recovered fluorophore parameters highly depend on the size and depth of the object due to the ill-posedness of the FT inverse problem. Structural a priori information from another high spatial resolution imaging modality has been demonstrated to significantly improve FT reconstruction accuracy. In this study, we have constructed a combined magnetic resonance imaging (MRI) and FT system for small animal imaging. A photo-multiplier tube is used as the detector to acquire frequency domain FT measurements. This is the first MR-compatible time-resolved FT system that can reconstruct both fluorescence concentration and lifetime maps simultaneously. The performance of the hybrid system is evaluated with phantom studies. Two different fluorophores, indocyanine green and 3-3' diethylthiatricarbocyanine iodide, which have similar excitation and emission spectra but different lifetimes, are utilized. The fluorescence concentration and lifetime maps are both reconstructed with and without the structural a priori information obtained from MRI for comparison. We show that the hybrid system can accurately recover both fluorescence intensity and lifetime within 10% error for two 4.2 mm-diameter cylindrical objects embedded in a 38 mm-diameter cylindrical phantom when MRI structural a priori information is utilized.

Relationship between pulse wave velocity and carotid atherosclerosis in geriatric people

OBJECTIVE

To investigate the relationship between the pulse wave velocity (PWV) and angiographic carotid atherosclerosis in elderly patients.

METHOD

103 consecutive elderly patients were divided into two groups according to the results of cerebral angiography: carotid atherosclerosis group and normal carotid angiogram group. Basic clinical information was required by a standardized questionnaire. Carotid-femoral PWV (cfPWV) as a marker of Stiffness of artery was measured, Carotid intima media thickness (IMT) and carotid stenosis degree in angiography was evaluated. Independent-sample t test was used to evaluate the difference in cfPWV between the two groups, Bivariate associations between cfPWV and an index of extracoronary atherosclerosis (IMT and severity of stenosis) was performed.

RESULT

Among 103 subjects, 55 with carotid atherosclerosis and 48 with a normal carotid angiogram, a significant difference between the two groups in IMT and PWV was found (P<0.05), and the cfPWV was significantly correlated with IMT (r = 0.3222, P = 0.0315), but not severity of carotid stenosis (r = 0.1573, P = 0.3137).

CONCLUSION

cfPWV showed a positive correlation to carotid IMT, and maybe is a potentially useful adjunctive atherosclerotic risk marker to Identify of early carotid atherosclerosis.

Interleukin-21 is upregulated in hepatitis B-related acute-on-chronic liver failure and associated with severity of liver disease

The immune mechanism(s) that lead to hepatitis B-related acute-on-chronic liver failure (HB-ACLF) are poorly understood. Interleukin-21 is a newly discovered cytokine that is involved in autoimmune and inflammatory diseases. Its potential role in HB-ACLF remains unknown. The serum levels of 12 immune cytokines measured by cytometric bead arrays and the frequency of IL-21-secreting CD4+ T cells in peripheral blood mononuclear cells (PBMC) measured by intracellular cytokine staining were compared in moderate chronic hepatitis B (M-CHB, n = 20), severe chronic hepatitis B (S-CHB, n = 20), HB-ACLF (n = 39) and healthy controls (n = 10). PBMC from M-CHB patients or healthy subjects were stimulated with rhIL-21 in vitro, and cytokines in supernatants were measured by FlowCytomix. The frequencies of IL-21-secreting CD4+ T cells were higher in HB-ACLF (both P < 0.001) and S-CHB (P = 0.002 and 0.001) as compared to M-CHB patients and controls. Serum IL-21 levels were highest (P < 0.001) in HB-ACLF and positively associated with high MELD score (P = 0.001) and mortality (P = 0.038). Recovery from HB-ACLF was associated with reduced serum IL-21 levels (P = 0.003) and lower CD4+ IL-21(+) T-cell frequency (P = 0.006). The secretions of IL-1β (P < 0.001), IL-6 (P < 0.001), IL-10 (P < 0.001), IFN-γ (P = 0.001) and TNF-α (P = 0.042) from PBMC were significantly increased with rhIL-21 stimulation. In summary, IL-21 has a causal role in the development of severe liver inflammation, which is upregulated in HB-ACLF and associated with severity of liver disease.

From two-dimensional colloidal self-assembly to three-dimensional nanolithography

A number of "top-down" lithographic and "bottom-up" self-assembly methods have been developed to fabricate three-dimensional (3D) nanostructures to support the recent advances in nanotechnology. But they are limited by a number of factors such as fabrication cost, pattern resolution, and/or flexibility of geometry. Here we present a 3D nanolithography process that utilizes self-assembled nanospheres to create a periodic array of focal spots, which are then replicated across multiple depth in a transparent medium according to the Talbot effect. The Talbot field then exposes a pattern onto the underlying photoresist, recording the 3D intensity distribution. We have demonstrated designable complex 3D periodic structures with 80 nm minimum feature size, roughly one-fourth of the operating wavelength. This approach combines 2D colloidal self-assembly and 3D phase lithography, is robust, cost-effective, and widely applicable to nanoscale research and manufacturing.

Subclinical hypothyroidism and its association with lupus nephritis: a case control study in a large cohort of Chinese systemic lupus erythematosus patients

The aim of this study was to evaluate the prevalence of thyroid diseases in Chinese systemic lupus erythematosus (SLE) patients and the relevance of subclinical hypothyroidism (SCH) with lupus nephritis (LN). A large cohort of 1006 SLE patients was retrospectively analyzed. The prevalence of autoimmune thyroid disease was 2.78%, clinical hypothyroidism 1.69%, subclinical hypothyroidism 10.04%, central hypothyroidism 1.29%, hyperthyroidism 1.19%, euthyroid sick syndrome (ESS) 9.54%, and nodules 1.09%, respectively. Compared with the prevalence of thyroid abnormalities in the general Chinese population (0.91–6.05%), SCH was much higher (10.04%) in this study. In addition, SCH was more frequent in patients with LN (13.4%) than those without LN (7.3%, p = 0.001). Case control study was performed to explore the relative risk factors of SCH. In multiple logistic regression models, 24 h urine protein and estimated glomerular filtration rate (eGFR) were retained as independent correlates of SCH after adjusting for demographic variables, risk factors, and other potential confounders. The results of the present study suggest that SCH is a common complication in SLE patients, and closely related with LN.

Polyphenols from Parabarium huaitingii and their positive inotropic and anti-myocardial infarction effects in rats

Eight phenolic compounds, including (-)-epicatechin (1) and seven proanthocyanidins (2-8), were obtained from the butanol extract of Parabarium huaitingii (PHB). Their chemical structures were identified based on analyses of mass spectra (MS), NMR, CD spectra, and partial acid catalyzed thiolytic degradation. The observation made by laser scanning confocal microscope found a significant increase of the concentration of intracellular Ca²+ ([Ca²+](i)) in single myocytes when the PHB was added, while compounds 1 and 3 had the same physiological effect. Further investigations showed PHB had a dose-dependent positive inotropic effect on isolated right atria and papillary muscle of left ventricle of the rat, while having no significant influence on the spontaneous beating rate of the isolated right atria. The inotropic effect of PHB could be greatly abolished by pretreating the myocardium in Ca²+-free solution. These findings indicated that PHB could significantly increase [Ca²+](i) in myocytes, which was greatly dependent on the influx of extracellular Ca²+. Compounds 1 and 3 might be the effective ingredients of the inotropic effect of PHB. In addition, PHB could also significantly decrease the infarct size of the heart on acute myocardial infarction (AMI) model rats, which suggested its myocardial protective effect on ischemic myocardium. The positive inotropic effect of PHB, together with its myocardial protective effect on AMI, suggested that PHB had a promising potential for the prevention and treatment of heart failure, especially the one that was caused by AMI.

Chronic continuous positive airway pressure (CPAP) reduces airway reactivity in vivo in an allergen-induced rabbit model of asthma

Previous studies have demonstrated that chronic mechanical strain produced by continuous positive airway pressure (CPAP) reduces in vivo airway reactivity in rabbits and ferrets. For CPAP to potentially have a therapeutic benefit for asthmatic subjects, the reduction in airway responsiveness would need to persist for 12-24 h after its discontinuation, require application for only part of the day, and be effective in the presence of atopic airway inflammation. In the present study, airway responsiveness to acetylcholine or methacholine was measured during mechanical ventilation following three different protocols in which active, nonanesthetized, tracheotomized rabbits were treated with High vs. Low CPAP (6 vs. 0 cmH(2)O). 1) High CPAP was applied continuously for 4 days followed by 1 day of Low CPAP; 2) High CPAP was applied at night and Low CPAP during the daytime for 4 days, and 3) High CPAP was applied for 4 days in animals following ovalbumin (Ova) sensitization and challenge. For all three protocols, treatment with High CPAP resulted in significantly reduced airway responsiveness compared with treatment with Low CPAP. Cumulatively, our in vivo results in rabbits suggest that high CPAP, even when applied only at night, produces a persistent reduction of airway responsiveness. In addition, CPAP reduces airway responsiveness even in the presence of atopic airway inflammation.

Abstract P3-02-08: Detection of Circulating Tumor Cells Prior to Autologous Stem Cell Transplantation Is Predictive of Shorter Progression Free Survival in Metastatic Breast Cancer

Background: High dose chemotherapy (HDCT) in patients with metastatic breast cancer (MBC) followed by autologous hematopoietic stem cell transplantation (ASCT) offers high complete response rates compared to standard therapy. However, the bone marrow (BM) is a reservoir for disseminated tumor cells (DTC) and the inadvertent recruitment from BM of DTC, cancer stem cells (CSC), and non-leukocytes undergoing epithelial mesenchymal transition (EMT) during the CD34+ hematopoietic progenitor cell (HPC) mobilization could adversely impact clinical outcome. As epithelial cells in EMT possess stem-like properties, we evaluated the apheresis product for CSC and expression of EMT to ascertain if they had an impact on clinical outcome in the transplant setting. Methods: Twenty-one MBC patients treated with HDCT underwent apheresis to harvest HPC and subsequent ASCT. A peripheral blood (PB) sample was collected before apheresis (baseline) and again after ASCT (post-treatment) for enumeration of CTC by CellSearch (Veridex, LLC, Raritan, NJ). Furthermore, mononuclear cells (MNC) were isolated from 19 HPC-depleted apheresis products. An aliquot of MNC was further depleted of CD45+ leukocytes and then interrogated for expression of the EMT-inducing transcription factor TWIST1 by quantitative RT-PCR. Another aliquot of each MNC sample was analyzed by 6-color flow cytometry for the presence of CSC (CD326+CD44hiCD24lo) and with ALDH-1 activity (Aldefluor+ CSC), measured by Aldefluor (StemCell Technologies, Vancouver, BC). The logrank test was used to determine if progression-free survival (PFS) was associated with the number of CTCs at baseline and post-ASCT; baseline percentages of CSC and Aldefluor+ CSC; and expression of TWIST1 by non-leukocytes. Results: The median follow-up was 17 months with a median time to disease progression of 9.4 months. The median overall survival was 12.9 months. At follow-up, 7 patients had non-progressive disease (NPD) and 12 had progressive disease (PD). CTCs were detected in 6 pts (range, 1-115) at baseline and in 9 patients post-ASCT (range, 1-131). PD patients had statistically significantly higher % of CD326+ epithelial cells but not CSC within the HPC-depleted apheresis products when compared with identical apheresis products of NPD patients (0.20% vs. 0.11%; P=0.033). Aldefluor test was performed in 12 of 19 samples. Four samples with TWIST1 transcripts contained a significantly higher % of CD326+ Aldefluor+ CSC than the samples without TWIST (9.58% vs. 1.58%; P =0.007). The presence of CTC at baseline was associated with shorter progression-free survival (PFS) (P =0.027). However, PFS was not associated with the TWIST1 expression or with % of Aldefluor+ CSC detected in apheresis products.

Conclusion: Baseline CTC number was predictive of PFS. HDCT followed by ASCT did not reduce the number of CTC in patients with MBC. Finally, leukocyte-depleted apheresis products that expressed EMT-inducing TWIST1 transcripts contained higher % CSCs suggesting a strong linkage between circulating epithelial cells undergoing EMT and the production of cancer stem cells.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-02-08.

Abstract P3-02-07: Serum Angiogenic Factors but Not TGF-≥1 Are Positively Correlated with CTC in Metastatic Breast Cancer Patients

Background

Transforming growth factor (TGF)-b1 has pleiotropic effects in cancer. In the early stages of breast cancer, TGF-b may be responsible for immune tolerance through the activation of T-Regulatory cells (TR). On the other hand, in the late stages of disease, it may induce angiogenic factors [vascular endothelial growth factor (VEGF), interleukin-8 (IL-8) (in Bonnomet J Mammary Gland Biol Neoplasia 2010); and IL-17 (Pickens J Immunol 2010)], and epithelial to mesenchymal transition (EMT) which may lead to an increase in the number of circulating tumor cells (CTC) (Kim, Cell 2009). Therefore, we investigated the possible correlation between TGF-b1, CTC count, angiogenic factors and T-cell function of patients with locally advanced or metastatic breast cancer.

Methods

As an interim analysis of an on-going prospective study, sera and peripheral blood mononuclear cells (PBMC) were collected from breast cancer patients starting a new line of therapy. At analysis, study enrollment included 78 patients with breast cancer [19 with locally advance disease (LABC), 23 with non-metastatic inflammatory breast cancer (IBC), and 32 with metastatic disease (MBC) including 19 with IBC features], and 28 healthy donors (HD). Serum TGF-b1, VEGF, and IL-8 levels were measured by Milliplex Luminex kits (Millipore, Billerica, MA). CD4+CD25+CD127dim TR cells were enumerated in whole blood by FACS (BD Biosciences, San Jose, CA). PBMC were used to study the ability of T cells to synthesize cytokines following activation of the T-cell receptor by immobilized anti-CD3 antibodies. CTC were enumerated by CellSearch (Veridex, Raritan,

NJ). The Spearman Rho was calculated for nonparametric correlations and the Mann-Whitney U test was used to determine significant differences between median values.

Results

LABC patients and HD had a median serum TGF-b1 that was significantly higher than that of MBC patients (P = 0.042). There were statistically significantly positive correlations between serum TGF-b1 and the number of CD4+ T cells (rho = .226, P = .029) and IL-10 produced by %CD4+ (rho = .388, P = .002) and %CD8+ (rho = .459, P &lt; .001) T cells. Furthermore, there was a positive correlation between serum TGF-b1 and the % of CD8+, but not CD4+, T cells that produced IL-17 (rho = .250, P = .022). Serum TGF-b1 levels did not correlate with either % or number of TR cells. Although serum TGF-b1 level of MBC patients was independent of CTCs (24.4 ng/mL vs. 24.0 ng/mL, P = .317), MBC patients with CTC had significantly higher serum levels of angiogenic factors such as VEGF (530 ng/mL vs. 240 ng/mL, P=0.037) and IL-8 (45.6 pg/ml vs. 20.0 pg/ml P= .006) than those of patients with no CTC. Even so, MBC patients with or without CTC have similar % of CD4 and CD8 T-cell subsets that could be activated to produce IFN-g, IL-2, TNF-a, IL-17, or IL-10. Conclusion:

The concomitant presence of elevated serum TGF-ß1 levels and IL-10 producing T cells suggest immune suppression could facilitate disease progression of breast cancer. T-cell function is independent of CTC in MBC patients; however, serum VEGF and IL-8 levels were significantly elevated in MBC patients with CTC suggesting that vascular changes can facilitate tumor dissemination.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-02-07.

Abstract P3-09-01: Higher Serum miR-21 Expression Correlates with Higher Levels of VEGF and bFGF in Patients with Metastatic Breast Cancer

Background

MicroRNAs (miRNAs) play an important role in the regulation of tumorigenesis and metastatic process. MiR-21 is an oncomiR that is overexpressed by breast cancer tumor tissue and is associated with high tumor grade and negative hormone receptor status. MiR-21 can control angiogenesis by regulating vascular endothelial growth factor (VEGF) as well as the expression and secretion of basic fibroblast growth factor (bFGF). MiR-19a is a member of the miR-17-92 family that was shown to suppress breast cancer cell proliferation. As angiogenesis factors act as attractants of circulating tumor cells (CTCs), a strong predictor of overall survival in metastatic breast cancer (MBC), we investigated the relationship between CTC count, levels of VEGF and bFGF, and the expression of miR-21 and miR-19a in sera of MBC patients. Methods

RNA was extracted from sera collected from 33 MBC patients and 10 healthy donors (HD) using Total RNA purification Kit (Norgene Biotek Corporation, ON, Canada). The expression levels of miR-21, miR-19a and miR-192 were evaluated in triplicate by qRT-PCR using the TaqMan MicroRNA Assay (Applied Biosystems, Foster City, CA). Mir-192 was used to normalize the expression levels of miR-21 and miR-19a. The fold-change values were calculated using 2-DCt, where DCt= mean CTtarget-miRNA - mean CTmiR-192. CTCs were detected by CellSearch System (Veridex LLC, Warren, NJ). Serum VEGF and bFGF were determined using a multiplex bead assay (Millipore, Billerica, MA). Mann-Whitney U test was used to compare the miRNAs expression level between MBC patients and HD. Spearman's correlation was used to determine the association between the expression of miRNAs and growth factors. Results

There was a significantly higher median level of miR-21 in MBC patients compared with HD (22.8 versus 7.2, P=0.003), while the expression level of miR-19a was similar for both groups. On average, the relative abundance of miR-21 in sera (ratio of MBC versus HD) is 3.1-fold overexpression. Furthermore, levels of miR-21 was positively correlated with the serum levels of VEGF (Spearman Rho= 0.364; P= 0.038) and bFGF (Spearman Rho= 0.367; P = 0.036). CTCs were detected in 23 patients, ranged from 1 to 134 per 7.5 mL of peripheral blood. Patients with no CTCs had a significantly higher median level of miR-19a than patients with no CTC (6.5 vs 2.8, P =0.047). Conclusion

Our results support the notion that miR-21 overexpression may play a role in angiogenesis and metastasis by upregulating VEGF and bFGF in MBC. Undetectable CTC count may be related to overexpression of miR-19a, an epigenetic suppressor of breast tumor proliferation. Whereas overexpression of miR-19a may limit the tumor cells from entering the peripheral circulation, increasing miR-21 in the serum could accelerate the disease progression by promoting angiogenesis in MBC patients.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-09-01.