Structure-Dependent Biodistribution of Liposomal Spherical Nucleic Acids

Spherical nucleic acids (SNAs) are a class of nanomaterials with a structure defined by a radial distribution of densely packed, short DNA or RNA sequences around a nanoparticle core. This structure allows SNAs to rapidly enter mammalian cells, protects the displayed oligonucleotides from nuclease degradation, and enables co-delivery of other drug cargoes. Here, we investigate the biodistribution of liposomal spherical nucleic acid (LSNA) conjugates, SNA architectures formed from liposome templates and DNA modified with hydrophobic end groups (tails). We compared linear DNA with two types of LSNAs that differ only by the affinity of the modified DNA sequence for the liposome template. We use single-stranded DNA (ssDNA) terminated with either a low-affinity cholesterol tail (CHOL-LSNA) or a high-affinity diacylglycerol lipid tail (DPPE-LSNA). Both LSNA formulations, independent of DNA conjugation, reduce the inflammatory cytokine response to intravenously administered DNA. The difference in the affinity for the liposome template significantly affects DNA biodistribution. DNA from CHOL-LSNAs accumulates in greater amounts in the lungs than DNA from DPPE-LSNAs. In contrast, DNA from DPPE-LSNAs exhibits greater accumulation in the kidneys. Flow cytometry and fluorescence microscopy of tissue sections indicate that different cell populations-immune and nonimmune-sequester the DNA depending upon the chemical makeup of the LSNA. Taken together, these data suggest that the chemical structure of the LSNAs represents an opportunity to direct the biodistribution of nucleic acids to major tissues outside of the liver.

Abstract P5-04-02: Progesterone receptor (PR) antagonism by telapristone acetate (TPA): A randomized, placebo-controlled phase IIB pre-surgical window trial in women with stage 0-II breast cancer

Background: In vitro and preclinical data indicate that TPA, a selective PR modulator, has activity against hormone-sensitive early breast cancer. We conducted a pre-surgical window trial of oral TPA in Stage 0-II breast cancer to assess the effect of TPA on suppression of cell proliferation (Ki67), and on differential gene expression in responsive and non-responsive tumors.

Methods: We enrolled 70 pre and postmenopausal women into a 1:1 randomized, double-blind, placebo-controlled trial of oral TPA 12mg (Repros Therapeutics Inc.) for 2-10 weeks. The primary endpoint was Ki67 labelling, comparing diagnostic core needle biopsy to post-therapy surgical specimens. Ki67 changes were quantitated by dual immunohistochemistry (Ki67/pan-cytokeratin) and image analysis (Aperio ImageScope and Definiens Tissue Studio®). RNA-sequencing (using RNA extracted from the paraffin blocks) was performed with Illumina TruSeq RNA Coding Access method. Differential gene expression pre-post therapy was assessed, followed by Gene Set Enrichment Analysis for pathway analysis. Ki67 changes from baseline were tested with Paired signed-rank test. For gene expression analysis, p values were calculated by Wald test and adjusted for multiple comparisons by Benjamini-Hochberg method (adjusted p <0.05 and 2-fold gene expression cut-off).

Results: Among 61 evaluable women, (29 placebo and 32 TPA) 97% of tumors were ER or PR positive and 91% were ER and PR positive (balanced across arms). A significant 6% decrease in mean %Ki67 was seen in the TPA arm (p= 0.003). When stratified by menopause, the significance held in premenopausal women (n= 22, p= 0.03) but not in postmenopausal women (n=10, p= 0.08). However, a Ki67 decrease (4%) was also observed in placebo group (p = 0.04); this was non-significant after pre- postmenopausal stratification. Overall, differential gene expression analysis showed no significant modulation of genes in either group. Using a pre-specified response parameter (50% relative reduction in Ki67), we identified 12/32 (38%) “responders” in the TPA, and 9/29 (31%) in the placebo arm. In sub-group analysis of these responders, we found 103 genes to be significantly modulated by treatment in the TPA “responders”, but saw no significant change in any gene expression in placebo “responders”. Gene set enrichment analysis for the 103 genes showed that TPA blocked the progression of cell cycle genes (PTTG1, PLK1, UBE2C, HIST1H3F, PSMD3, and etc.) and suppressed PGR and ERBB2 expression. In a pre-planned pooled analysis, these results will be combined with NCT02314156, reported in SABCS abstract 851790.

Conclusions: An anti-proliferative (Ki67) signal of TPA was observed in early stage breast cancer patients, but interpretation was limited by placebo group changes. The TPA group demonstrated differential suppression of proliferation-related genes among Ki67 responders, but the placebo group did not. Ongoing analysis will examine signatures related to stemness, metastasis, and immune suppression (potentially better endpoints in trials targeting P signaling). These analyses may help us select the right population and the right biomarkers for future trials.

Citation Format: Lee O, Sullivan ME, Xu Y, Shidfar A, Ivancic D, Zeng Z, Singhal H, Helenowski I, Jovanovic B, Hansen N, Bethke K, Gann P, Gradishar WJ, Clare SE, Khan SA. Progesterone receptor (PR) antagonism by telapristone acetate (TPA): A randomized, placebo-controlled phase IIB pre-surgical window trial in women with stage 0-II breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-04-02.

Breast Hormone Concentrations in Random Fine-Needle Aspirates of Healthy Women Associate with Cytological Atypia and Gene Methylation

Sex steroid hormones contribute to breast cancer development, but data on concentrations of these within breast tissue are limited. We performed simultaneous multiparameter measurement of breast sex steroids, breast epithelial cytology, and DNA methylation in 119 healthy women (54 pre- and 65 postmenopausal) without a history of breast cancer. Random fine-needle aspiration (rFNA) of the breast was performed simultaneously with blood collection. Breast samples were analyzed by LC/MS-MS for estrone, estradiol, progesterone, androstenedione, and testosterone. Blood samples were assayed for estradiol and progesterone by immunoassay. Cytomorphology was classified using the Masood Score, and DNA methylation of eight genes was analyzed using quantitative multiplexed methylation-specific PCR, and expressed as the cumulative methylation index (CMI). Serum and breast concentrations of estradiol and progesterone showed significant correlation (Spearman r = 0.34, P_adj = 0.001 and r = 0.69, P_adj < 0.0006, respectively). Progesterone concentration was significantly higher in the premenopausal breast (P_adj < 0.0008), and showed a luteal surge. Breast estrone and estradiol concentrations did not differ significantly by menopause, but androstenedione concentration was higher in the breasts of postmenopausal women (P = 0.026 and P_adj = 0.208). Breast androgens were significantly correlated with breast density (Spearman r = 0.27, P_adj = 0.02 for testosterone) and CMI (Spearman r = 0.3, P_adj = 0.038 for androstenedione). Our data indicate that future larger studies of breast steroid hormones along with other parameters are feasible. Significant associations of breast androgen concentrations with breast density and gene methylation warrant future study. Cancer Prev Res; 11(9); 557-68. ©2018 AACR.

Nanofibrous PLGA electrospun scaffolds modified with type I collagen influence hepatocyte function and support viability in vitro

A major challenge of maintaining primary hepatocytes in vitro is progressive loss of hepatocyte-specific functions, such as protein synthesis and cytochrome P450 (CYP450) catalytic activity. We developed a three-dimensional (3D) nanofibrous scaffold made from poly(l-lactide-co-glycolide) (PLGA) polymer using a newly optimized wet electrospinning technique that resulted in a highly porous structure that accommodated inclusion of primary human hepatocytes. Extracellular matrix (ECM) proteins (type I collagen or fibronectin) at varying concentrations were chemically linked to electrospun PLGA using amine coupling to develop an in vitro culture system containing the minimal essential ECM components of the liver micro-environment that preserve hepatocyte function in vitro. Cell-laden nanofiber scaffolds were tested in vitro to maintain hepatocyte function over a two-week period. Incorporation of type I collagen onto PLGA scaffolds (PLGA-Chigh: 100 µg/mL) led to 10-fold greater albumin secretion, 4-fold higher urea synthesis, and elevated transcription of hepatocyte-specific CYP450 genes (CYP3A4, 3.5-fold increase and CYP2C9, 3-fold increase) in primary human hepatocytes compared to the same cells grown within unmodified PLGA scaffolds over two weeks. These indices, measured using collagen-bonded scaffolds, were also higher than scaffolds coupled to fibronectin or an ECM control sandwich culture composed of type I collagen and Matrigel. Induction of CYP2C9 activity was also higher in these same type I collagen PLGA scaffolds compared to other ECM-modified or unmodified PLGA constructs and was equivalent to the ECM control at 7 days. Together, we demonstrate a minimalist ECM-based 3D synthetic scaffold that accommodates primary human hepatocyte inclusion into the matrix, maintains long-term in vitro survival and stimulates function, which can be attributed to coupling of type I collagen.

STATEMENT OF SIGNIFICANCE

Culturing primary hepatocytes within a three-dimensional (3D) structure that mimics the natural liver environment is a promising strategy for extending the function and viability of hepatocytes in vitro. In the present study we generate porous PLGA nanofibers, that are chemically modified with extracellular matrix proteins, to serve as 3D scaffolds for the in vitro culture of primary human hepatocytes. Our findings demonstrate that the use of ECM proteins, especially type I collagen, in a porous 3D environment helps to improve the synthetic function of primary hepatocytes over time. We believe the work presented within will provide insights to readers for drug toxicity and tissue engineering applications.

Overexpression of lipid metabolism genes and PBX1 in the contralateral breasts of women with estrogen receptor-negative breast cancer

Risk biomarkers for estrogen receptor (ER)-negative breast cancer have clear value for breast cancer prevention. We previously reported a set of lipid metabolism (LiMe) genes with high expression in the contralateral unaffected breasts (CUBs) of ER-negative cancer cases. We now further examine LiMe gene expression in both tumor and CUB, and investigate the role of Pre-B-cell leukemia homeobox-1 (PBX1) as a candidate common transcription factor for LiMe gene expression. mRNA was extracted from laser-capture microdissected epithelium from tumor and CUB of 84 subjects (28 ER-positive cases, 28 ER-negative cases, 28 healthy controls). Gene expression was quantitated by qRT-PCR. Logistic regression models were generated to predict ER status of the contralateral cancer. Protein expression of HMGCS2 and PBX1 was measured using immunohistochemistry. The effect of PBX1 on LiMe gene expression was examined by overexpressing PBX1 in MCF10A cells with or without ER, and by suppressing PBX1 in MDA-MB-453 cells. The expression of DHRS2, HMGCS2, UGT2B7, UGT2B11, ALOX15B, HPGD, UGT2B28 and GLYATL1 was significantly higher in ER-negative versus ER-positive CUBs, and predicted ER status of the tumor in test and validation sets. In contrast, LiMe gene expression was significantly lower in ER-negative than ER-positive tumors. PBX1 overexpression in MCF10A cells up-regulated most LiMe genes, but not in MCF10A cells overexpressing ER. Suppressing PBX1 in MDA-MB-453 cells resulted in decrease of LiMe gene expression. Four binding sites of PBX1 and cofactor were identified in three lipid metabolism genes using ChIP-qPCR. These data suggest a novel role for PBX1 in the regulation of lipid metabolism genes in benign breast, which may contribute to ER-negative tumorigenesis.

Abstract OT3-02-09: Phase II pre-surgical window trial of telapristone acetate (TPA) in early breast cancer and DCIS patients: Distribution of TPA in plasma, normal breast tissue and tumors

Background:In vitro and preclinical data support the notion that anti-progesterone therapy will have activity against both estrogen and progesterone receptors (ER/PR) positive and negative breast cancer, but biomarkers of efficacy may differ in different types of breast cancer. We have conducted a pre-surgical window trial of oral telapristone acetate (TPA, CDB-4124) treatment in early breast cancer patients. This first ever trial of oral TPA for breast cancer and DCIS patients will provide us pilot biologic data that will help select the right population and the right biomarkers for future trials. Here we report distribution of TPA in plasma and breast normal tissue and tumors collected at surgery.

Methods:our trial was a 1:1 randomized, double-blind, and placebo-controlled pre-surgical window trial of oral TPA 12mg (Proellex, CDB-4124, Repros Therapeutics Inc.) treatment for 2-10 weeks. 70 pre and postmenopausal women undergoing surgery for Stage 0-II breast cancer were recruited to the study. The surgical samples of 61 patients were used to determine the concentrations of TPA and its mono-demethylated metabolite (dTPA, CDB-4453) in plasma and matched normal tissue and tumor by Liquid chromatography–tandem mass spectrometry at the Illinois Institute of Technology, while maintaining the blind for the primary endpoint of cell proliferation. Statistical significance and analysis were calculated by Wilcoxon matched-pairs signed rank test and non-parametric Spearman correlation.

Results: We found that 32/61 women displayed detectable plasma concentrations of TPA and dTPA (median with IQR) 109ng/mL (71.3, 216) and 46.5 ng/mL (34.2, 73.7), respectively. TPA concentration was 2.3 times higher than dTPA in plasma (p&lt;0.0001). The normal and tumor tissue samples of these 32 women were further analyzed. In normal tissue samples, the concentrations of TPA and dTPA were 283 ng/g (70.7, 326) and 51.0 ng/g (24.4, 122), respectively. TPA concentration was 5.5 fold higher than dTPA in normal tissue (p&lt;0.0001). In tumors, the TPA and dTPA concentrations were 137 ng/g (31.1, 278) and 36.4 ng/g (17.3, 68.7), respectively. TPA concentration was 3.8 fold higher than dTPA in tumors (p&lt;0.0001).Interestingly, TPA and dTPA were more abundant in normal tissue than in tumors (p=0.0005 for TPA, and p=0.0013 for dTPA). We found that TPA and dTPA was highly correlated in plasma (r=0.492, p=0.0042). Plasma TPA concentration was highly correlated with normal tissue concentration (r=0.61, p=0.0003) but non-significantly correlated with tumor concentration (r=0.32, p=0.147). However, the normal and tumor tissue concentrations of TPA and dTPA were highly correlated (r=0.71, p=0.0002 for TPA and r=0.556, p=0.0072 for dTPA).

Conclusions: Plasma TPA concentrations reflect concentration in normal breast tissue better than in tumors. However, within the breast, TPA concentration in normal and tumor tissue is correlated. Our trial is to be unblended shortly, and we plan to relate these results to the proliferative rates in tumor and normal tissue. The variability observed in plasma and tissue concentrations also suggests that pharmacogenomics studies may be appropriate in the future.

Citation Format: Lee O, Muzzio M, Ivancic D, Rogers C, Allu S, Khan SA. Phase II pre-surgical window trial of telapristone acetate (TPA) in early breast cancer and DCIS patients: Distribution of TPA in plasma, normal breast tissue and tumors [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT3-02-09.

Gene Methylation and Cytological Atypia in Random Fine-Needle Aspirates for Assessment of Breast Cancer Risk

Methods to determine individualized breast cancer risk lack sufficient sensitivity to select women most likely to benefit from preventive strategies. Alterations in DNA methylation occur early in breast cancer. We hypothesized that cancer-specific methylation markers could enhance breast cancer risk assessment. We evaluated 380 women without a history of breast cancer. We determined their menopausal status or menstrual cycle phase, risk of developing breast cancer (Gail model), and breast density and obtained random fine-needle aspiration (rFNA) samples for assessment of cytopathology and cumulative methylation index (CMI). Eight methylated gene markers were identified through whole-genome methylation analysis and included novel and previously established breast cancer detection genes. We performed correlative and multivariate linear regression analyses to evaluate DNA methylation of a gene panel as a function of clinical factors associated with breast cancer risk. CMI and individual gene methylation were independent of age, menopausal status or menstrual phase, lifetime Gail risk score, and breast density. CMI and individual gene methylation for the eight genes increased significantly (P < 0.001) with increasing cytological atypia. The findings were verified with multivariate analyses correcting for age, log (Gail), log (percent density), rFNA cell number, and body mass index. Our results demonstrate a significant association between cytological atypia and high CMI, which does not vary with menstrual phase or menopause and is independent of Gail risk and mammographic density. Thus, CMI is an excellent candidate breast cancer risk biomarker, warranting larger prospective studies to establish its utility for cancer risk assessment. Cancer Prev Res; 9(8); 673-82. ©2016 AACR.

Progesterone receptor antagonism inhibits progestogen-related carcinogenesis and suppresses tumor cell proliferation

PURPOSE

Blockade of the progestogen-progesterone receptor (PR) axis is a novel but untested strategy for breast cancer prevention. We report preclinical data evaluating telapristone acetate (TPA), ulipristal acetate (UPA), and mifepristone.

METHODS

Tumors were induced with medroxyprogesterone acetate (MPA) plus 7,12-dimethylbenz[a]anthracene (DMBA) in mice, and MPA or progesterone plus N-methyl-N-nitrosourea (MNU) in rats. Mammary gland histology, tumor incidence, latency, multiplicity, burden and histology were evaluated, along with immunohistochemical labeling of pHH3 (proliferation), CD34 (angiogenesis), and estrogen and progesterone receptors (ER and PR). A concentration gradient of TPA, UPA, and mifepristone was tested for growth inhibition of T47D spheroids.

RESULTS

In mouse mammary glands, no tumors formed, but TPA opposed the pro-hyperplastic effects of MPA (p = 0.002). In rats, TPA decreased tumor incidence (p = 0.037 for MPA + TPA vs. MPA, and p = 0.032 for progesterone + TPA vs. progesterone) and tumor burden (p = 0.042 for progesterone + TPA vs. progesterone), with significant decreases in pHH3 and CD34 positive cells. TPA and UPA were superior to mifepristone in growth inhibition of T47D spheroids.

CONCLUSION

TPA has consistent anti-tumorigenic effects in several models, which are accompanied by decreases in cell proliferation, angiogenesis, and hormone receptor expression.

Nipple Aspirate Fluid Hormone Concentrations and Breast Cancer Risk

Prior reports identify higher serum concentrations of estrogens and androgens as risk factors for breast cancer, but steroids in nipple aspirate fluid (NAF) may be more related to risk. Incident breast cancer cases and mammography controls were recruited. Sex steroids were measured in NAF from the unaffected breasts of cases and one breast of controls. Menopausal status and menstrual cycle phase were determined. NAF steroids were purified by HPLC and quantified by immunoassays. Conditional logistic regression models were used to examine associations between NAF hormones and case-control status. NAF samples from 160 cases and 157 controls were evaluable for hormones. Except for progesterone and dehydroepiandrosterone (DHEA), the NAF and serum concentrations were not significantly correlated. NAF estradiol and estrone were not different between cases and controls. Higher NAF (but not serum) DHEA concentrations were associated with cases, particularly among estrogen receptor (ER)-positive cases (NAF odds ratio (OR) = 1.18, 95 % confidence interval (CI) 1.02, 1.36). NAF DHEA was highly correlated with NAF estradiol and estrone but not with androstenedione or testosterone. Higher progesterone concentrations in both NAF and serum were associated with a lower risk of ER-negative cancer (NAF OR = 0.69, 95 % CI 0.51, 0.92). However, this finding may be explained by case-control imbalance in the number of luteal phase subjects (2 cases and 19 controls). The significantly higher concentration of DHEA in NAF of cases and its correlation with NAF estradiol indicates a potentially important role of this steroid in breast cancer risk; however, the negative association of progesterone with risk is tentative.

A randomized phase II presurgical trial of transdermal 4-hydroxytamoxifen gel versus oral tamoxifen in women with ductal carcinoma in situ of the breast

PURPOSE

Local transdermal therapy to the breast may achieve effective target-organ drug delivery, while diminishing systemic effects. We conducted a randomized, double-blind, placebo-controlled phase II trial comparing transdermal 4-hydroxytamoxifen gel (4-OHT) to oral tamoxifen (oral-T) in women with ductal carcinoma in situ (DCIS).

METHODS

Twenty-seven pre- and postmenopausal women were randomized to 4-OHT (4 mg/day) or oral-T (20 mg/day) for 6 to 10 weeks before surgery. Plasma, nipple aspirate fluid, and breast adipose tissue concentrations of tamoxifen and its major metabolites were determined by liquid chromatography/tandem mass spectrometry. The primary endpoint was Ki67 labeling in DCIS lesions, measured by immunohistochemistry. In plasma, insulin-like growth factor-1 (IGFI), sex hormone-binding globulin (SHBG), and coagulation protein concentrations were determined.

RESULTS

Posttherapy Ki67 decreased by 3.4% in the 4-OHT and 5.1% in the oral-T group (P ≤ 0.03 in both, between-group P = 0. 99). Mean plasma 4-OHT was 0.2 and 1.1 ng/mL in 4-OHT and oral groups, respectively (P = 0.0003), whereas mean breast adipose tissue concentrations of 4-OHT were 5.8 ng/g in the 4-OHT group and 5.4 ng/g in the oral group (P = 0.88). There were significant increases in plasma SHBG, factor VIII, and von Willebrand factor and a significant decrease in plasma IGFI with oral-T, but not with 4-OHT. The incidence of hot flashes was similar in both groups.

CONCLUSIONS

The antiproliferative effect of 4-OHT gel applied to breast skin was similar to that of oral-T, but effects on endocrine and coagulation parameters were reduced. These findings support the further evaluation of local transdermal therapy for DCIS and breast cancer prevention.

Abstract 1985: PBX1 regulated lipid metabolism gene expression and epithelial-mesenchymal transition independent of estrogen receptor

Introduction: Pre-B-cell leukemia homeobox-1 (PBX1) is a member of the three amino acid loop extension (TALE) family of homeodomain proteins that bind to DNA and regulate gene transcription by forming heterodimeric transcription complexes with Meis and Prep1. PBX1 is involved in cell fate determination during organogenesis and contributes to oncogenic activity in breast cancer. As a pioneer factor, PBX1 was found to drive ER signaling in ER+ breast cancer by remodeling the chromatin and increasing DNA accessibility. But the role of PBX1 in benign breast and ER- cancer cells is not clear. In our previous studies, we identified and validated that the expression of a set of lipid metabolism genes was higher in the contralateral breast of ER- tumor. Bioinformatic analysis on lipid metabolism gene promoter regions and revealed that PBX1 may act as a potential transcription factor to co-regulate those genes. In this study, we further investigate the function of PBX1 in ER- cells.

Methods: Among the ER- cell lines, we infected cell lines expressing low endogenous PBX1 (MCF10A and MDA-MB-231) with PBX1 gene in lentiviral vector. We also infected cell lines expressing high endogenous PBX1 (MDA-MB-453 and SK-BR-3) with PBX1-shRNA to knockdown PBX1. The expression of lipid metabolism genes was detected by qRT-PCR. Markers for epithelial-to-mesenchymal transition (EMT) including E-cadherin, vimentin, β-catenin and α-SMA were detected using Western blot. The effects of overexpression or knock-down of PBX1 on proliferation, migration, and invasion were measured using IncuCyte live cell imaging system. The expression of PBX1 protein was measured in benign contralateral breast and in the matching tumor using mmnunohistochemistry.

Results: Over-expression of PBX1 in ER- cell lines (MCF10A and MDA-MB-231) up-regulated lipid metabolism genes and promoted cell migration and invasion by inducing EMT (increased vimentin and decreased E-cadherin and β-catenin). In contrast, knocking-down PBX1 using shRNA in ER- cell lines (MDA-MB-453 and SK-BR-3) suppressed lipid metabolism gene expression. PBX1 was more highly expressed in benign tissues associated with ER- tumors compared to ER+ tumors. In tumor tissue, on the contrary, ER+ tumors shower higher PBX1 expression levels than ER- tumors.

Conclusion: PBX1 is a master regulator of lipid metabolism genes. PBX1 promoted cell migration and invasion by inducing EMT. PBX1 may play different roles and interact with different co-factors in ER+ tumors and in benign tissues associated with ER- tumors.

Citation Format: Ali Shidfar, Liannian Liu, Vamsi Parini, MiRan Choi, David Ivancic, Megan E. Sullivan, Demirkan B. Gursel, Seema A. Khan, Jun Wang. PBX1 regulated lipid metabolism gene expression and epithelial-mesenchymal transition independent of estrogen receptor. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1985. doi:10.1158/1538-7445.AM2015-1985

Abstract P3-08-02: Expression of lipid metabolism genes in tumor and contralateral unaffected breast are conversely associated with tumor estrogen receptor status

Background: The identification of women at risk for ER- cancer would allow optimization of breast cancer prevention strategies by guiding their recruitment to studies of agents with efficacy against ER- cancer and sparing them the toxicity of prevention agents effective only against ER+ cancer. In our previous studies, we identified lipid metabolism (LiMe) gene set in rFNA samples from contralateral unaffected breast (CUB) that was associated with tumor ER status. In the current study, we further validate LiMe gene expression in tumor and CUB at the mRNA and protein levels.

Methods: Tissue samples from 56 bilateral mastectomy cases (28 ER+ and 28 ER-) and 28 healthy reduction mammoplasty (RM) controls were used. The ER+ cases, ER- cases and controls were matched by age, race and menopausal status. We performed laser capture microdissection of epithelial cells in fresh frozen tissues from tumor and unaffected breast. Total RNA was extracted and LiMe genes were detected using Taqman low density gene expression arrays. The difference among groups was analyzed using ANOVA with Sidak multiple comparison adjustment. Three proteins (HMGCS2, ACSL3 and HPGD) were detected in FFPE sections of tumor and CUB tissues using immunohistochemistry.

Results: Among the 13 LiMe genes, 6 genes (DHRS2, HMGCS2, UGT2B7, UGT2B11, UGT2B28 and GLYATL1) were significantly higher in CUB of ER- cases compared to CUB of ER+ cases (2.2-2.9 fold, P&lt;0.05). In contrast, the expression of 5 genes (DHRS2, HMGCS2, UGT2B11, UGT2B28 and GSTT2) was significantly lower in ER- tumor compared to ER+ tumor (0.11-0.37 fold, P&lt;0.05). Immunohistochemistry of HMGCS2, ACSL3 and HPGD confirmed this pattern: protein levels were higher in ER- CUB than ER+ CUB, but lower in ER- tumor than in ER+ tumor. When CUB samples were compared with healthy controls, 7 genes (DHRS2, HMGCS2, UGT2B11, UGT2B28, GLYATL1, ALOX15B and SERHL) showed significantly higher expression in CUB of ER- cases (2.5-9.6 fold, P&lt;0.05), but not in CUB of ER+ cases. Four genes (ACSL3, APOD, AKR1B15 and HPGD) did not show any significant difference among groups.

Conclusion: Differential expression of the LiMe genes in the CUB is associated with ER- index tumors and may characterize the environment leading to the development of ER- breast cancer. The converse patterns in tumor and CUB by ER status suggest that LiMe genes may be regulated by different mechanisms in benign and malignant tissues. These genes are potential risk biomarkers of ER- breast cancer and generate novel etiologic hypotheses regarding the development of ER- versus ER+ disease.

GeneER-C vs ER+CER-T vs ER+TER-C vs RMER+C vs RMDHRS22.4 (0.034)*0.16 (0.042)*6.0 (0.014)*1.3HMGCS22.9 (0.050)*0.15 (0.0095)*6.5 (0.006)*2.2UGT2B72.2 (0.004)*0.771.81.0UGT2B112.4 (0.019)*0.11 (0.0068)*9.6 (0.013)*2.0UGT2B282.3 (0.009)*0.15 (0.018)*2.8 (0.029)*1.5GLYATL12.9 (0.010)*0.374.3 (0.026)*1.4GSTT21.10.37 (0.040)*1.51.3ALOX15B1.60.562.5 (0.016)*1.5SERHL1.80.294.9 (0.0047)*1.4ER-C: ER- CUB; ER+C: ER+ CUB; ER-T: ER- tumor; ER+T: ER+ tumor; RM: reduction mammoplasty

Citation Format: Ali Shidfar, David Ivancic, Megan E Sullivan, Pranjal Patankar, Seema A Khan, Jun Wang. Expression of lipid metabolism genes in tumor and contralateral unaffected breast are conversely associated with tumor estrogen receptor status [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-08-02.

RANKL expression in normal and malignant breast tissue responds to progesterone and is up-regulated during the luteal phase

The receptor activator of nuclear factor-κB ligand (RANKL) acts as a paracrine factor in progesterone-induced mammary epithelial proliferation and tumorigenesis. This evidence comes mainly from mouse models. Our aim was to examine whether RANKL expression in human normal and malignant breast is under the control of progesterone throughout the menstrual cycle. Breast epithelial samples were obtained by random fine needle aspiration (rFNA) of the contralateral unaffected breasts (CUB) of 18 breast cancer patients, with simultaneous serum hormone measurements. Genes correlated with serum progesterone levels were identified through Illumina microarray analysis. Validation was performed using qRT-PCR in rFNA samples from CUB of an additional 53 women and using immunohistochemistry in tissue microarrays of 61 breast cancer samples. Expression of RANKL, DIO2, and MYBPC1 was correlated with serum progesterone in CUB, and was significantly higher in luteal phase. RANKL and MYBPC1 mRNA expression were highly correlated between CUB and matched tumor samples. RANKL protein expression was also significantly increased in the luteal phase and highly correlated with serum progesterone levels in cancer samples, especially in hormone receptor positive tumors. The regulatory effects of progesterone on the expression of RANKL, DIO2, and MYBPC1 were confirmed in three-dimensional cultures of normal breast organoids. In normal breast and in breast cancer, RANKL mRNA and protein expression fluctuate with serum progesterone with highest levels in the luteal phase, suggesting that RANKL is a modulator of progesterone signaling in normal and malignant breast tissue and a potential biomarker of progesterone action and blockade.

Abstract P4-11-02: Mammary tumor formation induced by N-methyl-N-nitrosourea (MNU) is accelerated by natural and synthetic progesterone but suppressed by an anti-progesterone CDB4124

Background: CDB4124, anti-progesterone suppresses the development of carcinogen-induced ER+/PR+ mammary tumors in rats, and may have implications for prevention and treatment of human breast cancer. We hypothesize that progesterone (P4) and medroxyprogesterone acetate (MPA) will accelerate mammary carcinogenesis induced by MNU, however CDB4124 will efficiently suppress tumor formation stimulated by progesterone.

Methods: ovary intact female Sprague Dawley rats received a single intraperitoneal injection of 50mg/kg MNU at 4-5 weeks of age. 30mg of CDB4124 and 25mg of P4 or MPA (90 release pellets, Innovative research of America, Inc) were implanted in dorsal area at 3 weeks and 4 weeks after MNU injection, respectively. 10-11 rats were used for each treatment group. Tumor incidence, latency, multiplicity, and burden were recorded weekly. 9 weeks after MNU injection all the mice were euthanized and mammary tumors and glands were fixed in 10% (v/v) neutral buffered formalin. Plasma concentrations of CDB4124 and its metabolite CDB4453 were determined by LC-MS/MS.

Results: The first tumor appeared in the control group at 5 weeks, and in the P4 and MPA treated groups at 6 weeks after MNU injection. 7 weeks after MNU injection, mammary tumor incidence of MPA and P4 treated groups were 80% and 50%, respectively compared to 30% in the control group. 9 weeks after MNU injection all MPA treated mice, 80% of P4 treated mice, and 60% of control mice developed tumors. Tumor incidence, latency, multiplicity, and tumor weight were summarized as mean ± SD in Table 1.

[Table 1] Tumor latency, incidence, multiplicity, and burden in mammary tumorsTreatmentsLatency (days)Incidence(%)MultiplicityBurden (g)Control53.7 ± 12.9602.34.25 ± 7.02P453.6 ± 9.6802.64.11 ± 5.32MPA50.8 ± 7.71002.56.02 ± 4.85P4 + CDB412459.3 ± 11.53621.38 ± 0.61MPA + CDB412454.3 ± 10.7732.84.19 ± 4.39

Tumor latency of CDB4124 treated groups was increased; tumor incidence and burden (g) of CDB4124 treated groups were decreased compared to P4 and MPA treated groups. In particular, tumor incidence and burden of CDB4124 + P4 treated group were significantly lower than those of the control group. Plasma CDB4124 and CDB4453 were 11.6 ±5.88 ng/mL and 3.4±1.68 ng/mL, respectively. Histopathology of tumors and mammary glands and immuno-histochemical evaluations of Ki67, activated caspase-3, CD34, ER, and PR are currently underway.

Conclusions: Our results indicated that natural progesterone promotes MNU- induced mammary tumor formation similar to synthetic progesterone, MPA in rats. Under this tumor permissive environment, CDB4124 provided excellent prevention efficacy, suggesting good potential as breast cancer prevention agent.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-11-02.

Abstract P2-09-10: Antiprogestin CDB4124 suppressed progesterone receptor-mediated DNA binding activity, proliferation and gene expression in T47D cancer cells and normal human breast microstructures

Introduction: The majority of breast cancers are estrogen and progesterone receptor positive (ER+PR+); hence targeting PRs with anti-progestins should be a useful strategy for breast cancer therapy. New generation anti-progestins lack the high anti-glucocorticoid activity of older agents; we evaluated one of these (CDB4124, telapristone) for specific inhibition of PR binding to the progesterone receptor element (PRE); effect on cell proliferation in T47D cells; and expression of PR target genes in normal human breast microstructures cultured in 3D conditions. Methods: To measure PRE activity in T47D cells dual luciferase reporter assay was performed, cells transfected with PRE-luc plasmid and treated for a 24h with vehicle, progesterone (P4), medroxyprogesterone (MPA), or a PR agonist (R5020), as well as three doses of CDB4124 (10nM, 100nM, 1μM) alone or in combination with P4 or MPA or R5020. Separately, T47D cells were simulated E2 plus P4 with and without CDB4124 for 72h and processed for cell cycle analysis by flow cytometer. For measurement of PR target genes, normal human breast microstructures were isolated after digestion of reduction mammoplasty samples. These microstructures were treated with E2 and P4 alone or in combination with CDB4124 for 24h. RNAs were collected after 24h and reverse-transcribed to cDNA for real time PCR. All experiments were performed in triplicate. Results: Increased in relative luciferase activity indicate an increase in PRE activity of T47D cells when treated with R5020 (2212.36±53.11 RLA) or P4 (1548.5 ± 158.84 RLA) or MPA (1422.63 ± 209.84 RLA) at 10nM alone compared to vehicle (33.08 ± 10.16 RLA). In contrast, 1μM CDB4124 alone have similar PRE activity (26.64 ± 3.94 RLA) in comparison to vehicle. The hormone-stimulated PRE activity was completely inhibited in T47D cells treated with 1μM CDB4124 combined with P4 (25.758 ± 2.32 RLA) or MPA (32.21 ± 2.46 RLA). In cells treated with R5020 plus CDB4124, 80% of PRE activity was inhibited (476.57± 5.72 RLA) in comparison to R5020 alone. Cell cycle data in T47D cells using flow cytometry showed significant arrest in G1 phase, with 12.6% decrease at 1nM E2+10nM P4+ 1μM CDB4124, and 14.9% decrease at 1nM E2+50nM P4+1μM CDB4124, relative to cells treated with hormone alone. The S-phase fraction also showed significant decrease when1μM CDB4124 was added to cells treated with 1nM E2+10nM P4 (12.4% decrease) and to 1nM E2+50nM P4 (10.5% decrease). CDB4124 treatment also led to decrease in expression of PR target genes i.e. RANKL, SKG1, FKB5 in normal breast microstructure in 3D culture in presence of P4 [50nM] alone or in combination with 1nM E2 plus P4 [50nM].Conclusion: CDB4124 is a potent antiprogestin; it abrogates PRE activity in the presence of R5020, or P4, or MPA. Furthermore, significant inhibition of hormone-induced cell proliferation is observed in T47D cells treated with CDB4124. In addition, PR target gene expressions were inhibited in normal breast microstructures, Based on these results, we expect that targeting PR by CDB4124 will inhibit PR regulated genes involved in cell proliferation and survival of breast cancer cells.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-09-10.

Abstract 5670: In vitro and in vivo transdermal delivery of CDB4124, a progesterone receptor modulator: a potential method for breast cancer prevention

Background: CDB4124 a progesterone receptor modulator suppressed the development of precancerous lesions and carcinogen-induced ER+ mammary tumors in rats, and may have implications for prevention and treatment of human breast cancer; however liver toxicity in human is the major problem of systemic delivery, and transdermal local delivery to the breast may be an excellent solution. We tested transdermal CDB4124 for in vitro human skin permeation and in vivo tissue distribution in rats compared to s.c delivery.

Methods: We tested CDB4124 (Repros Therapeutics, Inc.) alone and with ethanol and 0.5 v/v % oleic acid (OA) using split-thickness skin from mastectomy specimens, mounted in Franz diffusion cells (PermeGear, PA, USA), 0.5mg of CDB4124 in 60 % alcoholic solution +/- OA and applied to the donor chamber. Aliquots of the receiver solution were collected at pre-determined time points for 24 hr. Next, we tested the in vivo permeation of gel formulation of CDB4124 + 0.5% OA in nude rats comparing daily transdermal delivery (0.3mg/day) with a s.c pellet (30mg) for 6 weeks. Plasma and mammary fat pads(MFPs) were collected. CDB4124 and its major metabolite CDB4453 were quantified by LC-MS/MS.

Results: The permeation through human breast skin was 3.1± 0.9% for CDB4124 alone and enhanced 4-fold to 11.6±1.5% with the addition of 0.5% OA at 24 hr. The rate of CDB4124 permeation was 5-fold faster than the drug alone within 12 hr. Plasma levels of CDB4124 were 14±5 and 11±5 ng/mL for the pellet and gel groups, respectively (p= 0.16); plasma level of CDB4453 was higher in the pellet group than in the gel group, 4.6±2 vs. 1.5±0.6 ng/mL (p=0.000). CDB4124 levels in the upper MFP (the site of gel application) were 34-fold higher in the gel group than in the pellet group (1485ng/g for gel group; 44ng/g for pellet group, p=0.000); CDB4124 levels in the lower MFP were 194 ng/g for gel group; 66 ng/g for pellet group. CDB4124 and CDB4453 levels in upper MFP were significantly higher than in lower MFP (about 8-fold for CDB4124 and 7-fold for CDB4453; p=0.000, p=0.000, respectively). In contrast, the pellet group shows a similar concentration of CDB4124 and CDB4453 in the upper and lower MFPs.

Conclusions: This is an encouraging result because skin permeation of CDB4124 is similar to the level of estradiol, an efficacious transdermal agent, and indicating more extensive metabolism of CDB4124 when administered systemically. The high CDB4124 tissue level in the gel group indicate the possibility that drug smeared on the skin area other than the upper MFP, but the higher level of the metabolite CDB4453 supports the conclusion that a significant portion of the drug measured in the fat pad was in fact delivered to the tissue. Local transdermal delivery of CDB4124 seems plausible method for breast cancer prevention.

Citation Format: Oukseub Lee, David Ivancic, Ali Shidfar, Ronald Wiehle, Seema A. Khan. In vitro and in vivo transdermal delivery of CDB4124, a progesterone receptor modulator: a potential method for breast cancer prevention . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5670. doi:10.1158/1538-7445.AM2013-5670

Lipid metabolism genes in contralateral unaffected breast and estrogen receptor status of breast cancer

Risk biomarkers that are specific to estrogen receptor (ER) subtypes of breast cancer would aid the development and implementation of distinct prevention strategies. The contralateral unaffected breast of women with unilateral breast cancer (cases) is a good model for defining subtype-specific risk because women with ER-negative (ER-) index primaries are at high risk for subsequent ER-negative primary cancers. We conducted random fine needle aspiration of the unaffected breasts of cases. Samples from 30 subjects [15 ER-positive (ER+) and 15 ER- cases matched for age, race and menopausal status] were used for Illumina expression array analysis. Findings were confirmed using quantitative real-time PCR (qRT-PCR) in the same samples. A validation set consisting of 36 subjects (12 ER+, 12 ER- and 12 standard-risk healthy controls) was used to compare gene expression across groups. ER- case samples displayed significantly higher expression of 18 genes/transcripts, 8 of which were associated with lipid metabolism on gene ontology analysis (GO: 0006629). This pattern was confirmed by qRT-PCR in the same samples, and in the 24 cases of the validation set. When compared to the healthy controls in the validation set, significant overexpression of 4 genes (DHRS2, HMGCS2, HPGD and ACSL3) was observed in ER- cases, with significantly lower expression of UGT2B11 and APOD in ER+ cases, and decreased expression of UGT2B7 in both subtypes. These data suggest that differential expression of lipid metabolism genes may be involved in the risk for subtypes of breast cancer, and are potential biomarkers of ER-specific breast cancer risk.

Abstract P3-04-08: Expression of hormone-responsive genes in benign breast tissue varies with menstrual cycle phase and menopausal status

Background: The expression of many genes is known to be regulated by ambient hormone levels. In a preliminary study of random fine-needle aspirate (rFNA) samples from benign breast tissue, we found several genes that were highly correlated with the serum levels of progesterone (P4) and estradiol (E2). We now present data to further validate these genes as markers of menstrual cycle phase (MCP) and menopausal status (MPS) in benign breast tissue which may allow retrospective classification of archived breast samples with respect to MCP and MPS at the time of sampling.

Methods: 240 rFNA samples from healthy women with recorded hormonal data at the time of sampling were analyzed. We divided these subjects by menstrual cycle phase (MCP) and menopausal status (MPS): 41 early follicular: (low circulating E2 and P4); 48 mid-cycle (high E2 and low P4); 31 luteal (moderate E2 and high P4). 120 post-menopausal (low E2 and low P4). 100 ng of RNA from rFNA samples of the breast was reverse transcribed. Amplicons of interest were linearly amplified to 14 cycles for 35 genes related to hormone responsiveness. qPCR reactions were carried out using the TaqMan OpenArray (Applied Biosystems). For each gene of interest, expression levels were normalized to the average expression of GAPDH. Gene expression difference between groups were conducted using the Mann-Whitney Test. P-values from gene expression difference were adjusted via the Benjamini-Hochberg (1995) approach.

Results: The mean value of TNFSF11 expression level was 13.19 fold higher in luteal phase subjects than in post-menopausal subjects (p = 0.0003) where there was also the biggest difference of serum P4 level between groups. The expression of DIO2 and MYBPC1 was also significantly higher in luteal phase group than in the post-menopausal group (p = 0.005, p = 0.02, respectively). These 3 genes also demonstrated a higher expression pattern in luteal phase than mid-cycle and follicular phase but analysis is still ongoing. All comparisons between these groups will be presented at the meeting.

Conclusion: The expression levels of TNFSF11, DIO2 and MYBPC1 vary with MCP and MPS. These hormone-responsive genes are candidate MCP classifiers which could be applied to archived breast samples to assess whether biomarkers of breast cancer risk are stable across the menstrual cycle, since MCP and MPS variation is likely an important source of biological noise in studies of archived breast biopsy material.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-04-08.

Gene methylation in random FNA samples as biomarkers for breast cancer

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Background: Current methods to determine breast cancer risk are insufficiently sensitive to select women most likely to benefit from preventive strategies. We hypothesized that candidate gene promoter hypermethylation may provide an individualized risk profile. We performed a prospective study to determine whether DNA cumulative methylation index (CMI) varies by menstrual phase or menopausal status, and to correlate CMI with established risk factors. Methods: We obtained random fine needle aspiration (rFNA) samples from healthy women age 35-60 and determined their menopausal and menstrual status, lifetime Gail risk, mammographic breast density, and cytologic atypia assessed as the Masood score. We evaluated CMI of 11 candidate genes in rFNA cells using the Quantitative Multiplex Methylation-Specific PCR (QM-MSP) technique. We used Wilcoxon test and ANOVA model to compare CMI across menopausal and menstrual (follicular, mid-cycle, luteal) categories, respectively. We used linear regression model to adjust for age and BMI. Methylation scores were log-transformed in the analysis. Results: We enrolled 390 women at the Avon Breast Centers at Johns Hopkins and Northwestern, the majority through the Love/Avon Army of Women, and 380 completed study procedures. Median age 50 (36-60), mean BMI 28 (18.7-50.8), 52% were postmenopausal. Mean life-time Gail risk 14.6 (5.6-54.1), mean percent mammographic density 19.6 (2.5-72.8), and mean Masood score (N=354) 13.6 (7-18). QM-MSP analysis was completed on 229 samples. We did not observe differences in CMI among menopausal (P=0.4895) or menstrual categories (P=0.2333). There was no association between CMI and life-time Gail risk (P=0.706) or breast density (P=0.4116). We observed a significant correlation between CMI and Masood score (P=0.0167). Conclusions: CMI correlates with degree of cytologic atypia and is potentially a robust indicator of breast cancer risk since it does not vary with menstrual or menopausal status. Next, we will select genes that best reflect changes in the clinical parameters to create a gene methylation signature that will be validated in other studies and correlated with breast cancer risk.

Soy isoflavone supplementation for breast cancer risk reduction: a randomized phase II trial

Soy isoflavone consumption may protect against breast cancer development. We conducted a phase IIB trial of soy isoflavone supplementation to examine its effect on breast epithelial proliferation and other biomarkers in the healthy high-risk breast. One hundred and twenty-six consented women underwent a random fine-needle aspiration (rFNA); those with 4,000 or more epithelial cells were randomized to a double-blind 6-month intervention of mixed soy isoflavones (PTIG-2535) or placebo, followed by repeat rFNA. Cells were examined for Ki-67 labeling index and atypia. Expression of 28 genes related to proliferation, apoptosis, and estrogenic effect was measured using quantitative reverse transcriptase PCR. Hormone and protein levels were measured in nipple aspirate fluid (NAF). All statistical tests were two-sided. Ninety-eight women were evaluable for Ki-67 labeling index. In 49 treated women, the median Ki-67 labeling index was 1.18 at entry and 1.12 post intervention, whereas in 49 placebo subjects, it was 0.97 and 0.92 (P for between-group change: 0.32). Menopausal stratification yielded similar results between groups, but within premenopausal soy-treated women, Ki-67 labeling index increased from 1.71 to 2.18 (P = 0.04). We saw no treatment effect on cytologic atypia or NAF parameters. There were significant increases in the expression of 14 of 28 genes within the soy, but not the control group, without significant between-group differences. Plasma genistein values showed excellent compliance. A 6-month intervention of mixed soy isoflavones in healthy, high-risk adult Western women did not reduce breast epithelial proliferation, suggesting a lack of efficacy for breast cancer prevention and a possible adverse effect in premenopausal women.

P3-04-03: Identification of Hormone-Responsive Genes as Biomarkers for Menstrual Cycle Phases and Menopausal Status

Background

The definition and validation of biomarkers in archived breast tissue samples for prognostic research is limited by the fact that the exact menstrual cycle phases and menopausal status at the time of tissue sampling is often unknown or not accurate by patient survey. Biomarkers that vary with menstrual cycle phases in premenopausal women would be difficult to standardize. There are also significant differences in gene expression in pre- and post-menopausal women. Therefore, menstrual cycle fluctuation and menopausal status need to be considered for all candidate biomarkers as part of the validation process. The aim of this study is to identify genes responsive to different hormones to accurately define menstrual cycle phases and menopausal status.

Methods: We studied gene expression profiles of 18 random fine-needle aspirate (rFNA) samples from unaffected contralateral breast (8 pre-menopausal, mean age 44.5; 10 post-menopausal, mean age 58.8) and investigated the correlation between gene expression and serum hormone levels of estradiol (E2), progesterone (P4) and follicle stimulating hormone (FSH). Genes that were highly correlated with the serum levels of each hormone (Pearson correlation coefficient r &gt; 0.60) were considered as specific hormone-responsive genes (P &lt; 0.0085). The combined gene profiles of hormone-responsive genes were used to dissect samples in different menstrual cycle phases and menopausal status. Selected genes related to mammary gland development and hormone regulation based on gene function and gene network analysis were validated using qRT-PCR in 18 original rFNA samples and in 28 independent samples.

Results: From 35,964 genes and 12,838 undesignated transcripts, we identified genes/transcripts highly correlated with E2 (1091 genes), P4 (127 genes) or FSH (58 genes). The most significantly correlated genes in each group were selected to define four panels of genes: Panel A-21genes stimulated by E2 (r &gt; 0.78); Panel B-22 genes stimulated by P4 (r &gt; 0.75); Panel C-7 genes stimulated by FSH (r &gt; 0.65); and Panel D-10 genes suppressed by FSH (r &lt; −0.65). Hierarchical clustering analysis using the combination of gene panels dissected the samples into four clusters based on three phases of menstrual cycles and post-menopausal status. Specifically, high panel C and low panel D expression segregated post- from pre-menopausal samples. Low expression of panel A and B genes dissected early follicular phase from late follicular and luteal phases, while higher expression of panel B genes discriminated luteal phase from late follicular samples.

Conclusion: Our results indicate that the menstrual cycle phases and menopausal status determined by age, patient survey and serum hormone concentrations are reflected in the expression of specific gene sets in the normal breast. The combination of hormone-responsive gene panels would allow the classification of breast samples regarding to the menstrual phases and menopausal status at the time of sampling. It would also facilitate the selection and validation of breast cancer biomarkers that are independent of menstrual cycle fluctuation and menopausal variation for clinical use.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-04-03.

Relationship of recent pregnancy and cytologic atypia in the contralateral breast of patients with breast cancer

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Background: Although early parity protects against breast cancer later in life, it is a risk factor in the years following pregnancy, particularly when child-bearing is delayed. In a separate study, we have reported that these pregnancy-associated breast cancers (PABC) are more likely to be hormone receptor (HR) negative; we have previously found that random fine needle aspiration (rFNA) of the contralateral breast (CB) frequently have atypia in women with HR negative breast cancer. We now report an analysis of the cytological features of contralateral rFNA in relation to recent parity, with the goal of assessing cytological features which may be risk factors for PABC.

Methods: Women with breast cancer undergoing surgery between 2006 and 2008 were enrolled in a prospective study of rFNA of the CB. Cytological analysis was performed on all the samples, using two scoring systems, Masood and Zalles (M and Z). Linear regression analyses were performed relating each score to interval from last pregnancy, stratified for parity, and adjusted for age.

Results: Eighty-two patients had rFNA and cytologic analysis. The parous group’s (n=52) interval since last pregnancy was inversely correlated with the overall M score (p=0.034); pleomorphism and (p=0.047 and p=0.013 respectively). M score was also related to age at last pregnancy (p=0.026) as were pleomorphism and chromatin pattern (p=0.044 and 0.035 respectively). In the nulliparous group (n=30), there were no significant relationships between any of the cytological parameters or age.

Conclusions: The CB of women with recent parity display specific cytological abnormalities that are related to risk of breast cancer, particularly HR negative breast cancer. This observation affords the opportunity to further evaluate rFNA as a tool for breast cancer risk assessment following pregnancy, and to identify molecular correlates of nuclear cytological abnormalities that may serve as targets for prevention of ER negative breast cancer.

In vitro human skin permeation of endoxifen: potential for local transdermal therapy for primary prevention and carcinoma in situ of the breast

PURPOSE

Oral tamoxifen, a triphenylethylene (TPE), is useful for breast cancer prevention, but its adverse effects limit acceptance by women. Tamoxifen efficacy is related to its major metabolites 4-hydroxytamoxifen (4-OHT) and N-desmethyl-4-hydroxytamoxifen (endoxifen [ENX]). Transdermal delivery of these to the breast may avert the toxicity of oral tamoxifen while maintaining efficacy. We evaluated the relative effciency of skin permeation of 4-OHT and ENX in vitro, and tested oleic acid (OA) as a permeation-enhancer.

METHODS

4-OHT, ENX, and estradiol (E2) (0.2 mg/mL of 0.5 μCi (3)H/mg) were dissolved in 60% ethanol-phosphate buffer, ±OA (0.1%-5%). Permeation through EpiDerm™ (Matek Corp, Ashland, MA) and split-thickness human skin was calculated based on the amount of the agents recovered from the receiver fluid and skin using liquid scintillation counting over 24 hours.

RESULTS

In the EpiDerm model, the absorption of 4-OHT and ENX was 10%-11%; total penetration (TP) was 26%-29% at 24 hours and was decreased by OA. In normal human skin, the absorption of 4-OHT and ENX was 0.3%; TP was 2%-4% at 24 hours. The addition of 1% OA improved the permeation of ENX significantly more than that of 4-OHT (P < 0.004); further titration of OA at 0.25%-0.5% further improved the permeation of ENX to a level similar to that of estradiol.

CONCLUSION

The addition of OA to ENX results in a favorable rapid delivery equivalent to that of estradiol, a widely used transdermal hormone. The transdermal delivery of ENX to the breast should be further developed in preclinical and clinical studies.

Abstract 5566: In vitro human skin permeation enhancement of endoxifen by oleic acid

Background: Oral medication for breast cancer prevention is associated with systemic exposure and resulting adverse effects; there is a need for alternative drug delivery approaches. Transdermal drug delivery is such an option, and 4-Hydroxy-N-desmethytamoxifen (endoxifen, ENX) is an excellent candidate for development for this route. ENX is an active metabolite of tamoxifen with major therapeutic effect related to potent estrogen antagonism and ability to cause proteosomic degradation of ERα. We hypothesize that skin permeation of ENX with oleic acid (OA) will be equivalent or superior to that of estradiol (E2), which is a well-established transdermal agent.

Methods: Split-thickness human skin samples (354 ± 25 micron) were prepared from de-identified fresh mastectomy specimens under an IRB approved protocol using a surgical blade and placed in Franz diffusion cells (PermeGear, Inc.). ENX was prepared in 60 % (v/v) ethanol/phosphate buffer (PB) +/- OA (0.1to 1% v/v). E2 was used as a positive control drug, prepared in 60 % ethanol/PB. The receiver fluid was PBS, pH 7.4 with 4% (w/v) polyoxyethylene 20 oleyl ether (Sigma-Aldrich). 100 µL of the drug solution (30 µg + 0.1µCi of 3H-E2 or 3H-ENX) was loaded in the donor chamber. Receiver fluid was stirred at 37° C. A sample of receiver fluid was collected for 3H counting from 4 to 24 hr point with 2 hr interval. Each permeation experiment was performed in duplicate for each treatment condition using the breast skin of one individual. The permeation experiments were repeated three times with the skin from different individuals.

Results: Results were expressed as the mean and standard deviation (SD) of the % of the applied dose. Absorption is defined as the amount of drug passing into the receiver fluid. We found that the absorption of E2 was 0.2 ± 0.17% (at 12hr) and 3.16 ± 2.79 % (at 24hr) of the applied dose while the absorption of ENX was 0.07± 0.08 % (at 12hr) and 1.45 ± 1.07 % (at 24hr). In the presence of OA, the permeation of ENX was enhanced by 2 to 12- fold at 12 hr and by 1.2 to 3.8- fold at 24 hr. At the 12 hr point, the absorption of ENX alone is one third of that of E2 alone (p = 0.09) however in the presence of 0.25, 0.5, and 1% (v/v) of OA, the absorption of ENX was by 4.4-fold (p = 0.02), 6.4-fold (p = 0.01), and 3-fold (p = 0.02) higher than E2, respectively. At 24 hr, there was no further significant enhancement in the absorption of ENX by 0.25 and 0.5% of OA compared to that of E2. The addition of 0.1 and 1% OA made the absorption of ENX retarded than that of E2 at 24 hr.

Conclusion: The skin permeation of ENX was significantly enhanced in the presence of 0.25-1 % of oleic acid and was superior to that of E2 alone at 12 hr. Our results imply that the topical delivery of endoxifen is a potential option for breast cancer prevention with no or minimal systemic toxicity/side effects. Efficacy remains to be demonstrated, but is highly likely given the data on the parent compound (tamoxifen).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5566. doi:10.1158/1538-7445.AM2011-5566

Abstract P6-10-02: Differential qRT-PCR-Based Gene Expression Signatures by Menopausal Status and Menstrual Phase in Random Fine-Needle Aspiration Samples from Healthy High-Risk Women

Background: The utility of archived breast tissue samples for risk-related research is limited by the fact that menopausal and menstrual status at the time of tissue sampling is often unknown. We evaluated the expression of a panel of genes in degraded RNA samples from women undergoing random fine-needle aspirate (rFNA) in preparation for a soy-isoflavone intervention. Our goal was to identify breast epithelial gene expression patterns related to menopause and menstrual phase.

Methods: Among 86 at high risk women (a 5-year Gail risk estimate &gt;1.6%, or a prior history of contralateral breast cancer but no systemic therapy), 46 were premenopausal (mean age 43.8 years) and 40 were postmenopausal (mean age 55 years). Stratification by menopause and menstrual phase was accomplished using menstrual dates and plasma estradiol (E2) and progesterone(P4) concentrations, measured by radioimmunoassay. 100 ng of RNA from baseline rFNA samples of the breast was reverse transcribed(mean RNA integrity 3.2). Amplicons of interest were linearly amplified to 10 cycles for 28 genes related to breast cancer and estrogen responsiveness. Assays were designed with small amplicons (&lt;100 bp) and qPCR reactions were carried out using the TaqMan Low Density Arrays (Applied Biosystems). For each gene of interest, expression levels were normalized to the average expression of GAPDH and HPRT1. The means, standard deviations, and 95% confidence intervals were calculated for plasma E2, P4, and gene expression difference between pre-and postmenopausal groups, and between the follicular and luteal phase within the premenopausal group were conducted using the unpaired t-test. P-values from gene expression difference were adjusted via the Benjamini-Hochberg (1995) approach.

Results: Within the premenopausal women group, there was no significant change in plasma E2 level between follicular and luteal phase groups (p=0.1756) while P4 level was higher in luteal phase (p=0.0474). The expression of five genes was significantly higher in the premenopausal than in the postmenopausal group: relative expression was 5-fold higher for progesterone receptor (PGR), 6-fold for pS2 (TFF1), 7-fold for gene regulated in breast cancer 1 protein (GREB1), 2-fold for prolactin receptor (PRLR) and 2-fold for CyclinD1 (CCND1) (adjusted p&lt; 0.026 for all). Within the premenopausal women group, the expression of ERα (ESR1) was one-third lower, and the signal peptide, CUB domain, EGF-like 2 (SCUBE2) was one-fifth lower in the luteal phase group compared to the follicular phase group (adjusted p=0.0423 for ESR1, p=0.0076 for SCUBE2).

Conclusion: Our findings suggest that the expression of genes related to estrogenic response in the breast epithelium of premenopausal women declines following menopause, whereas the relative suppression of ESR1 and SCUBE2 relate to effects of progesterone during the luteal phase of the menstrual cycle. These changes may allow the development of a model to date archived breast samples by menopausal and menstrual status.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-10-02.

Abstract 2907: Endoxifen, a potential alternative to 4-OHT gel for chemoprevention

Background: Topical application of 4-hydroxytamoxifen (4-OHT) to the breast has been reported to inhibit breast tumor cell proliferation to the same degree as the standard dose of oral tamoxifen (TAM) and results in substantially lower systemic effects. Recently, 4-Hydroxy-N-desmethytamoxifen (endoxifen, ENX), another active anti-estrogenic metabolite of TAM has been reported to give a major therapeutic effect because of its abundance and ability to cause proteosomic degradation of ERα. We hypothesize that transdermal permeation of ENX will be significantly enhanced by chemical permeation enhancers (CPEs), making it superior to that of 4-OHT. For the first time, we are reporting the skin permeation of ENX compared to 4-OHT using split-thickness skin of human breast.

Methods: De-identified human skins were obtained from mastectomy specimens with IRB approval. The split-thickness skin were prepared using a surgical dermatome from fresh skin and placed in the MatTek Corp. permeation device (MPD). Procedures for permeation studies were followed as recommended by MatTek Corp. 4-OHT and ENX were prepared in 60 % ethanol/phosphate buffer +/− oleic acid (OA). The receiver solution was phosphate buffered saline (PBS), pH 7.4. 200 µL of the drug solution (40 µg + 0.1µCi of 3H-4-OHT or 3H-ENX) was loaded in the donor chamber. Receiver solutions were stirred at 37° C. The samples of receiver solutions at 24 hr were collected for 3H counting. The percent permeation of the 3H-4-OHT and 3H-ENX was calculated based on the ratio of the amount of 3H-drugs recovered from the receiver to total dose loaded on donor chamber. All permeation experiments were performed in triplicate with a minimum of 4 skin replicates.

Figure 1. Percent permeation of 4-OHT and ENX using split-thickness human skin at 24 h.

Results: Our permeation study using split-thickness skin samples showed relatively small and consistent intra/inter- batch variance in permeation experiments. (figure 1). We found that although the permeation of 4-OHT alone is two-fold higher than that of ENX alone (p=0.006), in the presence of 1 to 2.5% (v/v) of OA, the permeation of ENX was improved by 5 to 7-fold compared to that of ENX alone (p=0.000) and was 2-fold higher than that of 4-OHT+OA (p=0.000). Although the permeation of ENX with OA cotreatment is 1.4%, this is four-fold higher than that of the 4-OHT topical gel being used in a NIH-sponsored clinical trial.

Conclusion: We have found that transdermal permeation of ENX was significantly enhanced in the presence of oleic acid and was superior to that of the 4-OHT topical gel being tested in a current clinical trial. We have been actively screening other CPEs and nano-particles for improving ENX permeation. In addition, we will shortly initiate studies to validate anti-tumor efficacy of ENX in an appropriate animal model for transdermal delivery.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2907.

Epithelial NF-kappaB enhances transmucosal fluid movement by altering tight junction protein composition after T cell activation

In inflammatory bowel disease (IBD), aberrant activation of innate and adaptive immune responses enhances mucosal permeability through mechanisms not completely understood. To examine the role of epithelial nuclear factor (NF-kappaB) in IBD-induced enhanced permeability, epithelial-specific IkappaBalpha mutant (NF-kappaB super repressor) transgenic (TG) mice were generated. NF-kB activation was inhibited in TG mice, relative to wild-type mice, following T cell-mediated immune cell activation using an anti-CD3 monoclonal antibody. Furthermore, epithelial NF-kappaB super repressor protein inhibited diarrhea and blocked changes in transepithelial resistance and transmucosal flux of alexa350 (0.35 kDa) and dextran3000 (3 kDa). In vivo perfusion loop studies in TG mice revealed reversed net water secretion and reduced lumenal flux of different molecular probes (bovine serum albumin, alexa350, and dextran3000). Cell-imaging and immunoblotting of low-density, detergent-insoluble membrane fractions confirmed that tight junction proteins (occludin, claudin-1 and zona occludens-1) are internalized through an NF-kappaB-dependent pathway. Taken together, these data suggest that IBD-associated diarrhea results from NF-kappaB-mediated tight junction protein internalization and increased paracellular permeability. Thus, reduction of epithelial NF-kappaB activation in IBD may repair defects in epithelial barrier function, reduce diarrhea, and limit protein (eg, serum albumin) losses. Epithelial NF-kappaB activation induced by mucosal T cells, therefore, actively plays a role in opening paracellular spaces to promote transmucosal fluid effux into the intestinal lumen.

Ductal lavage is an inefficient method of biomarker measurement in high-risk women

Effective methods of serial epithelial sampling to measure breast-specific biomarkers will aid the rapid evaluation of new preventive interventions. We report here a proof-of-principle phase 2 study to assess the utility of ductal lavage (DL) to measure biomarkers of tamoxifen action. We enrolled women with a 5-year breast cancer risk estimate >1.6% or the unaffected breast of women with T1a or T1b breast cancer. After entry DL, participants chose tamoxifen or observation and underwent repeat DL 6 months later. Samples were processed for cytology and immunohistochemistry for estrogen receptor alpha, Ki-67, and cyclooxygenase-2. Of 182 women recruited, 115 (63%) underwent entry and repeat DL; 85 (47%) had sufficient cells for analysis from > or =1 duct at both time points; in 78 (43%), cells were sufficient from > or =1 matched ducts. Forty-six women chose observation and 39 chose tamoxifen. We observed greater reductions in the tamoxifen group than in the observation group for Ki-67 (adjusted P = 0.03) and estrogen receptor alpha (adjusted P = 0.07), but not in cyclooxygenase-2 (adjusted P = 0.4) labeling. Cytologic findings showed a trend toward improvement in the tamoxifen group compared with the observation group. Interobserver variability for cytologic diagnosis between two observers showed good agreement (kappa = 0.44). Using DL, we observed the expected changes in tamoxifen-related biomarkers; however, poor reproducibility of biomarkers in the observation group, the 53% attrition rate of subjects from recruitment to biomarker analyses, and the expense of DL are significant barriers to the use of this procedure for biomarker assessment over time.

Tissue-specific transcripts of human steroid sulfatase are under control of estrogen signaling pathways in breast carcinoma

Steroid sulfatase (STS) increases the pool of precursors of biologically active steroids, thereby playing an important role in breast cancer development. Mechanisms that control STS expression remain poorly understood. In present study we investigated alterations in the 5' region of STS gene to gain insight into the mechanism(s) that regulates its expression in mammary epithelial cells. We found that at least four alternatively spliced transcripts of STS gene can be produced from at least four different leader exons. Distinct expression patterns of the STS variants were observed in human tissues. Expression profiles of estrogen receptor alpha (ERalpha)-positive and ERalpha-negative breast carcinomas showed that these two categories of tumors and their adjacent benign tissues display remarkably different expression of STS isoforms. Coexpression of STS isoforms with ER isotypes suggests their cell-type specific coregulation. In addition, we identified ERalpha as essential regulator of STS transcription and provide evidence of direct estradiol-dependent binding of ERalpha to multiple STS cis-regulatory regions in vivo. Our results indicate that STS isoforms are under control of estrogen signaling pathways and their differential expression may play a significant role in breast cancer biology.

IP-10-induced recruitment of CXCR3 host T cells is required for small bowel allograft rejection

BACKGROUND & AIMS

Chemokines mediate cell trafficking in inflammatory states such as allograft rejection. However, their role in small-bowel allograft rejection has not been defined. The aim of this study was to examine the roles of type 1 helper T-cell chemokines in small-bowel allograft rejection.

METHODS

Mucosal histology, chemokine messenger RNA (real-time polymerase chain reaction), and cell isolates were examined in small-bowel allografts and isografts. Interferon-gamma-inducible protein-10/CXC chemokine receptor (CXCR) 3 interactions were specifically evaluated by using allografts from interferon-gamma-inducible protein-10(-/-) donors and adoptive transfer of CXCR3(-/-) T cells into recombination activating gene (RAG)-1(-/-) recipients of small-bowel allografts.

RESULTS

Type 1 helper T-cell cytokine (interferon-gamma) and chemokine (interferon-gamma-inducible protein-10, monokine induced by interferon-gamma, macrophage-inflammatory protein-1 alpha, and regulated on activation, normal T cells expressed and secreted) messenger RNA up-regulation was detected (real-time polymerase chain reaction) by postoperative day 3 in small-bowel allografts. Interferon-gamma-inducible protein-10(+/+) small-bowel allograft rejection was associated with a dramatic (>7-fold) increase in CXCR3(+) host T cells in the graft lamina propria. With interferon-gamma-inducible protein-10(-/-) small-bowel allografts, CXCR3(+) host T-cell infiltration of the graft lamina propria was markedly decreased and rejection was significantly delayed. Whereas adoptive transfer of wild-type B6 (CXCR3(+/+)) T cells into B6 (RAG-1(-/-)) recipients induced rapid rejection of CB6F1 small-bowel allografts, rejection was significantly delayed (29.2 +/- 8.7 days vs. 16.5 +/- 3.1 days; P < 0.01) in B6 (RAG-1(-/-)) mice reconstituted with T cells from B6 (CXCR3(-/-)) mice.

CONCLUSIONS

Recruitment of CXCR3(+) host T cells by donor derived interferon-gamma-inducible protein-10 may precipitate small-bowel allograft rejection. These data highlight the importance of type 1 helper T cell-related chemokines in promoting cell-mediated rejection responses in small-bowel allografts and suggest that interferon-gamma-inducible protein-10 is an attractive therapeutic target for humanized monoclonal antibody strategies.

Differential effects of T-cell activation on gastric and small bowel permeability in alcohol-consuming mice

BACKGROUND

A number of variables influence the effect(s) of alcohol on distinct segments of the intestine. In these studies, we examined the effect of T-cell activation on gastric and small bowel permeability in alcohol-fed mice.

METHODS

Gastric permeability was assessed using sucrose absorption, whereas small bowel permeability was followed using the ratio of lactulose to mannitol absorption and inulin absorption. T cells were activated by injecting antigen OVA(323-339) into DO11.10 T-cell receptor transgenic mice.

RESULTS

T-cell activation increased gastric and small bowel permeability through a pathway mediated by interferon-gamma and tumor necrosis factor. In mice that were fed a liquid diet that contained 30% ethanol-derived calories for 2 weeks, T-cell activation increased gastric permeability to levels greater than that observed in solid diet or pair-fed, liquid control diet. By comparison, changes in small bowel permeability induced by T-cell activation were abrogated in alcohol-fed mice. Analysis of intestinal cytokine mRNA levels (interferon-gamma and tumor necrosis factor) indicated that relevant mucosal T-cell function was preserved in alcohol-fed mice.

CONCLUSIONS

Overall, these data suggest that alcohol potentiates the effects of T-cell activation on gastric permeability, at the same time blunting effects on small bowel permeability

Donor T cell activation initiates small bowel allograft rejection through an IFN-gamma-inducible protein-10-dependent mechanism

The poor success in controlling small bowel (SB) allograft rejection is partially attributed to the unique immune environment in the donor intestine. We hypothesized that Ag-induced activation of donor-derived T cells contributes to the initiation of SB allograft rejection. To address the role of donor T cell activation in SB transplantation, SB grafts from DO11.10 TCR transgenic mice (BALB/c, H-2L(d+)) were transplanted into BALB/c (isografts), or single class I MHC-mismatched (L(d)-deficient) BALB/c H-2(dm2) (dm2, H-2L(d-)) mutant mice (allografts). Graft survival was followed after injection of control or antigenic OVA(323-339) peptide. Eighty percent of SB allografts developed severe rejection in mice treated with antigenic peptide, whereas <20% of allografts were rejected in mice treated with control peptide (p < 0.05). Isografts survived >30 days regardless of OVA(323-339) administration. Activation of donor T cells increased intragraft expression of proinflammatory cytokine (IFN-gamma) and CXC chemokine IFN-gamma-inducible protein-10 mRNA and enhanced activation and accumulation of host NK and T cells in SB allografts. Treatment of mice with neutralizing anti-IFN-gamma-inducible protein-10 mAb increased SB allograft survival in Ag-treated mice (67%; p < 0.05) and reduced accumulation of host T cells and NK cells in the lamina propria but not mesenteric lymph nodes. These results suggest that activation of donor T cells after SB allotransplantation induces production of a Th1-like profile of cytokines and CXC chemokines that enhance infiltration of host T cells and NK cells in SB allografts. Blocking this pathway may be of therapeutic value in controlling SB allograft rejection.

Single vs. dual vessel porcine extracorporeal liver perfusion

BACKGROUND

The use of porcine extracorporeal liver perfusion (PECLP) to provide temporary hepatic support for patients in fulminant hepatic failure has been limited by the fact that individual perfusions can be sustained for only a few hours. Inadequate liver function and/or hemodynamic instability are the major contributing factors for early interruption of PECLP. Recent reports suggest that the choice of single (portal vein only) vs dual (portal vein and hepatic artery) vessel perfusion may influence the duration of perfusion. We hypothesize that PECLP with single vessel perfusion (SVP) is associated with worse liver function and greater hemodynamic instability than PECLP with dual vessel perfusion (DVP).

MATERIALS AND METHODS

To eliminate the potentially confounding influences of liver failure and xenograft rejection, liver isografts procured from White-Landrace pig donors were perfused by either SVP or DVP via an extracorporeal circuit established with normal White-Landrace pig recipients. The function of perfused livers was evaluated by measuring production of bile and Factors V and VIII, clearance of ammonia and lactate, and extraction of O(2) at baseline and at 0, 1, 3, 6, 12, and 24 h after initiation of PECLP. The impact of PECLP on recipient hemodynamic status was assessed by monitoring BP, heart rate, urine output, O(2) saturation, etc. Among other parameters evaluated were serum albumin and total protein and hepatic release of IL-1beta and nitric oxide to assess their possible contributions to hemodynamic instability.

RESULTS

DVP and SVP livers cleared ammonia and lactate similarly. Both approaches were associated with progressive hypoalbuminemia and hypoproteinemia. DVP livers produced more bile and Factor V and were associated with less recipient hypotension and IL-1beta and NO release than SVP livers.

CONCLUSIONS

Livers with DVP function better than livers with SVP. The duration of PECLP can be limited by recipient hypotension, although this complication is less severe with DVP than with SVP.

Distribution of, and immune response to, chicken anti-alpha Gal immunoglobulin Y antibodies in wild-type and alpha Gal knockout mice

Chicken antibodies (immunoglobulin Y; IgY) to the alpha Gal epitope (galactose alpha-1,3-galactose) bind to alpha Gal antigens of mouse and porcine tissues and endothelial cells in vitro and block human anti-alpha Gal antibody binding, complement activation and antibody-dependent cell-mediated lysis mechanisms. The activities and toxicity of anti-alpha Gal IgY have not been tested in vivo. In this study, we tested the effects of multiple injections of affinity-purified anti-alpha Gal IgY (AP-IgY) in both wild-type (WT) and alpha-1,3-galactosyltransferase knockout (Gal KO) mice. WT and Gal KO mice were injected once, twice, three, or four times intravenously (i.v.) with AP-IgY and killed at 1 hr or 24 hr. Mice displayed no toxicity to four injections of AP-IgY. Heart, lung, liver, kidney, spleen and pancreatic tissue were evaluated using immunohistochemical techniques for the presence of the alpha Gal epitope using the GSI-B4 lectin, and for bound IgY, as well as mouse IgM and IgG. The binding of AP-IgY antibodies to the endothelium of WT mouse tissues was essentially identical to the pattern of binding of the GSI-B4 lectin after injection of WT mice and death at 1 hr. WT mice killed 24 hr after i.v. injection of AP-IgY showed little remaining bound IgY in their endothelia, indicating that IgY is cleared over that time period. We also evaluated the blood drawn at the time of death for the presence of anti-alpha Gal IgY, anti-IgY IgM and anti-IgY IgG by enzyme-linked immunosorbent assay. Anti-alpha Gal IgY was almost undetectable in WT mouse sera at all injection and killing times. In contrast, Gal KO mouse sera showed increasing anti-alpha Gal IgY levels until 24 hr after the fourth injection, when anti-alpha Gal IgY levels were almost undetectable. Anti-IgY IgM and IgG levels in WT and Gal KO mouse sera showed a typical increase in anti-IgY IgM 24 hr after the second injection (3 days after the first injection) and an increase in anti-IgY IgG 24 hr after the third injection (5 days after the first injection). These results show that IgY binds to alpha Gal epitopes in the WT mice and is cleared sometime over a 24-hr time period and that IgY is an expected immunogen in mice eliciting a rather typical anti-IgY IgM and IgG response.

Synthetic peptides which inhibit the interaction between C1q and immunoglobulin and prolong xenograft survival

BACKGROUND

Acute vascular xenograft rejection (AVXR), also termed delayed xenograft rejection (DXR), occurs when hyperacute rejection (HAR) is prevented by strategies directed at xenoreactive natural antibodies and/or complement activation. We have hypothesized that AVXR/DXR is initiated in part by early components of the complement cascade, notably C1q. We have developed synthetic peptides (termed CBP2 and WY) that interfere with the interaction between C1q and antibody.

METHODS

CBP2 and the WY-conjugates were used as inhibitors of immunoglobulin aggregate binding to solid phase C1q. Inhibition of complement activation by the peptides of the classical system was determined using lysis assays with sensitized sheep red blood cells or porcine aortic endothelial cells as targets and of the alternate complement pathway using guinea pig red blood cells as targets. Two transplant models were used to study the effects of administering peptides to recipients: rat heart transplant to presensitized mouse, and guinea heart transplant to PVG C6-deficient rats.

RESULTS

CBP2 and WY-conjugates inhibited immunoglobulin aggregate binding to C1q. The peptides also inhibited human complement-mediated lysis of sensitized sheep red blood cells and porcine aortic endothelial cells in a dose-dependent manner and the WY-conjugates prevented activation of the alternate complement pathway as shown by inhibition of guinea pig red blood cells lysis with human serum. In addition, the use of the peptides and conjugates resulted in significant prolongation of xenograft survival.

CONCLUSIONS

The CBP2 and WY peptides exhibit the functional activity of inhibition of complement activation. These peptides also prolong xenograft survival and thus provide reagents for the study of the importance of C1q and other complement components in transplant rejection mechanisms.

IgY antiporcine endothelial cell antibodies effectively block human antiporcine xenoantibody binding

Avian IgY antibodies are structurally different from mammalian IgGs and do not fix mammalian complement components or bind human Fc receptors. As these antibody-mediated interactions are believed to play significant roles in both hyperacute rejection (HAR) and acute vascular xenograft rejection (AVXR), IgY antibodies to xenoantigen target epitopes may inhibit these rejection processes. In this report, we show that chicken IgY antibodies to alpha-Gal antigen epitopes and to other porcine aortic endothelial cell (PAEC) antigens block human xenoreactive natural antibody binding to both porcine and rat cardiac tissues and porcine kidney tissues. Chicken IgY antibodies blocked complement-mediated lysis of PAECs by human serum, and inhibited antibody-dependent cell-mediated lysis of PAECs by heat-inactivated human serum plus peripheral blood leukocytes. Binding of IgY to porcine endothelial cells did not affect cell morphology nor expression of E-selectin. These results suggest that avian IgYs could be of potential use in inhibiting pig-to-human xenograft rejection.

Early histopathology of small intestinal discordant xenografts

A descriptive study of a new model enabling serial biopsies of ongoing hyperacute rejection of small intestinal discordant xenografts is presented. In a series of guinea-pig-to-Lewis rat small bowel xenotransplants (n=7), aboral free ends of Thierry-Vella loops constructed from the graft were sequentially biopsied at one-minute intervals up to ten minutes post-reperfusion and less frequently thereafter. In a guinea pig-to-guinea pig (n=6) isograft series, biopsy controls for preservation/ischemia-reperfusion injury were obtained. Xenoantibody sequestration in this model was evaluated in a separate series of transplants, utilizing an ELISA assay for rat anti-guinea pig natural antibodies. Pathologic evaluation revealed a unique series of events characterized with microcirculatory failure and thrombosis progressing from the submucosal vasculature to the lumen. Within the system's detection limits, complement deposition and P-selectin expression occurred as early as one minute post-reperfusion, preceding the staining for IgM and IgG. Using rat serum ELISAs, no significant difference in xenoantibody sequestration was detected between the xenograft and isograft groups. The guinea pig-to-rat discordant small bowel xenotransplantation is an efficient small animal model to dissect the very early pathophysiologic events during hyperacute rejection.