Citations

Abstract Some studies suggest that estrogen acts on bone by decreasing the production of interleukin-6 (IL-6), a cytokine that increases bone resorption, by osteoblasts or bone marrow cells. However, other studies have not confirmed this, possibly because of a low and variable number of estrogen receptors (ER) in the model systems used. Thus, we employed a recently developed human fetal osteoblast cell line with high levels of ER. Treatment (n = 4 experiments) with 0.01 to 10 nM of 17β-estradiol had no effect on the constitutive production of IL-6. However, stimulated production, induced by treatment with IL-1β plus tumor necrosis factor-α (TNF-α), was reduced in a dose-dependent manner to 74 + 3% (mean + SEM) of control (p < 0.01). This response was blocked by cotreatment with the type II antiestrogen ICI 182,780. Treatment with hydrocortisone (1 μM), a known inhibitor of IL-6 production in many cell types, reduced IL-6 production to 17 + 1% of control (p < 0.001). As assessed by Northern analysis, treatment (n = 3 experiments) with 0.01-10 nM of 17β-estradiol decreased steady-state levels of IL-6 mRNA in a dose-dependent manner. These data support the hypothesis that at least part of the antiresorptive action of estrogen in humans is mediated by decreased production of IL-6 by osteoblastic cells.

Ectopic Myc expression plays a key role in human tumorigenesis, and Myc dose-dependent tumorigenesis has been well established in transgenic mice, but the Myc target genes that are dependent on Myc levels have not been well characterized. In this regard, we used the human P493-6 B cells, which have a preneoplastic state dependent on the Epstein–Barr viral EBNA2 protein and a neoplastic state with ectopic inducible Myc, to identify putative ectopic Myc target genes. Among the ectopic targets, JAG2 that encodes a Notch receptor ligand Jagged2, was directly induced by Myc. Inhibition of Notch signaling through RNAi targeting JAG2 or the γ-secretase Notch inhibitor N-[N-(3,5-difluorophenacetyl)-L-alanyl]-(S)-phenylglycine t-butyl ester (DAPT) preferentially inhibited the neoplastic state in vitro. Furthermore, P493-6 tumorigenesis was inhibited by DAPT in vivo. Ectopic expression of JAG2 did not enhance aerobic cell proliferation, but increased proliferation of hypoxic cells in vitro and significantly increased in vivo tumorigenesis. Furthermore, the expression of Jagged2 in P493-6 tumors often overlapped with regions of hypoxia. These observations suggest that Notch signaling downstream of Myc enables cells to adapt in the tumor hypoxic microenvironment.

Acute ischemic insults to the kidney are recognized complications of human sickle cell disease (SCD). The present study analyzed in a transgenic SCD murine model the early renal response to acute ischemia. Renal hemodynamics were profoundly impaired following ischemia in sickle mice compared with wild-type mice: glomerular filtration rate, along with renal plasma flow and blood flow rates, were markedly reduced, while renal vascular resistances were increased more than threefold in sickle mice following ischemia. In addition to these changes in renal hemodynamics, there were profound disturbances in renal signaling processes: phosphorylation of members of the MAPK and Akt signaling proteins occurred in the kidney in wild-type mice after ischemia, whereas such phosphorylation did not occur in the kidney in sickle mice after ischemia. ATP content in the postischemic kidney in sickle mice was less than half that observed in wild-type mice. Examination of the expression of candidate genes uncovered changes that may predispose to increased sensitivity of the kidney in sickle mice to ischemia: increased expression of inducible nitric oxide synthase and decreased expression of endothelial nitric oxide synthase, and increased expression of TNF-α. Inducibility of anti-inflammatory, cytoprotective genes, such as heme oxygenase-1 and IL-10, was not impaired in sickle mice after ischemia. We conclude that the kidney in SCD is remarkably vulnerable to acute ischemic insults. We speculate that such sensitivity of the kidney to ischemia in SCD may underlie the occurrence of acute kidney injury in patients with SCD and may set the stage for the emergence of chronic kidney disease in SCD.

AbstractPurpose: Over the past two decades, there has been significant interest in targeting HER-2/neu in immune-based approaches for the treatment of HER-2/neu+ cancers. For example, peptide vaccination using a CD8 T cell–activating HER-2/neu epitope (amino acids 369-377) is an approach that is being considered in advanced phase clinical trials. Studies have suggested that the persistence of HER-2/neu–specific CD8 T cells could be improved by incorporating human leukocyte antigen (HLA) class II epitopes in the vaccine. Our goal in this study was to identify broad coverage HLA-DR epitopes of HER-2/neu, an antigen that is highly expressed in a variety of carcinomas.Experimental Design: A combination of algorithms and HLA-DR–binding assays was used to identify HLA-DR epitopes of HER-2/neu antigen. Evidence of preexistent immunity in cancer patients against the identified epitopes was determined using IFN-γ enzyme-linked immunosorbent spot (ELIspot) assay.Results: Eighty-four HLA-DR epitopes of HER-2/neu were predicted, 15 of which had high binding affinity for ≥11 common HLA-DR molecules. A degenerate pool of four HLA-DR–restricted 15-amino acid epitopes (p59, p88, p422, and p885) was identified, against which >58% of breast and ovarian cancer patients had preexistent T-cell immunity. All four epitopes are naturally processed by antigen-presenting cells. Hardy-Weinberg analysis showed that the pool is useful in ∼84% of population. Lastly, in this degenerate pool, we identified a novel in vivo immunodominant HLA-DR epitope, HER-2/neu88-102 (p88).Conclusion: The broad coverage and natural immunity to this epitope pool suggests potential usefulness in HER-2/neu–targeting, immune-based therapies such as vaccines. Clin Cancer Res; 16(3); 825–34

Objective. We investigated the correlation between immunohistochemical expression of the pituitary tumor transforming gene (PTTG) and pituitary adenoma subtype. Methods. Pituitary adenomas (n = 89) were stained for PTTG using the streptavidin—biotin—peroxidase complex method and a monoclonal PTTG antibody. Results. PTTG staining was found to be cytoplasmic with a pronounced paranuclear expression pattern. Reactivity was highest in growth hormone (GH) adenomas as compared with other tumors, including prolactin (PRL), follicle-stimulating hormone/luteinizing hormone/α subunit, as well as adrenocorticotrophic hormone—secreting adenomas. PRL adenomas exhibited the lowest expression levels. Among GH adenomas, untreated tumors demonstrated significantly higher PTTG levels than octreotide-treated examples. Although dopamine agonist—treated PRL adenomas tended to show lower expression levels, statistical significance was not reached. Conclusions. Our finding that PTTG was differentially expressed in pituitary adenoma subtypes suggests a cell-specific function for PTTG. Moreover, treatment of GH adenomas with somatostatin analogues lowered PTTG expression. Further investigation into mechanisms mediating cell-specific expression of PTTG is warranted.

Abstract Purpose: Some 85% of lung cancers are smoking related. Here, we investigate the role of serine protease HtrA3 in smoking-related lung cancer. Experimental Design: We assess HtrA3 methylation and its corresponding expression in the human bronchial cell line BEAS-2B following cigarette smoke carcinogen treatment, in lung cancer cell lines and in primary lung tumors from light, moderate, and heavy smokers. We also show the effects of HtrA3 downregulation on MTT reduction and clonogenic survival with etoposide and cisplatin treatment and the corresponding effects of HtrA3 re-expression during treatment. Results: We show for the first time that HtrA3 expression is reduced or completely lost in over 50% of lung cancer cell lines and primary lung tumors from heavy smokers. Treatment of HtrA3-deficient cell lines with 5-aza-2′-deoxycytidine resulted in a dose-dependent increase in HtrA3 transcription. Further, sequence analysis of bisulfite-modified DNA from lung cancer cell lines and from primary lung tumors showed an increased frequency of methylation within the first exon of HtrA3 with a corresponding loss of HtrA3 expression, particularly in tumors from smokers. In BEAS-2B, treatment with the cigarette smoke carcinogen 4-(methylnitrosamino)-I-(3-pyridyl)-1-butanone resulted in HtrA3 downregulation with a corresponding increase in methylation. Additional studies indicate resistance to etoposide and cisplatin cytotoxicity as a functional consequence of HtrA3 loss. Finally, immunohistochemical analysis of primary lung tumors revealed a strong correlation between low HtrA3 expression and heavy smoking history. Conclusions: Collectively, these results suggest that cigarette smoke–induced methylation of HtrA3 could contribute to the etiology of chemoresistant disease in smoking-related lung cancer. Clin Cancer Res; 16(2); 398–409

Abstract Aromatase (CYP19) is a critical enzyme in estrogen biosynthesis and aromatase inhibitors (AI) are employed widely for endocrine therapy in postmenopausal women with breast cancer. We hypothesized that single nucleotide polymorphisms (SNPs) in the CYP19 gene may alter the effectiveness of AI therapy in the neoadjuvant setting. Genomic DNA was obtained for sequencing from 52 women pre-AI and post-AI treatment in this setting. Additionally, genomic DNA obtained from 82 samples of breast cancer and 19 samples of normal breast tissue was subjected to resequencing. No differences in CYP19 sequence were observed between tumor and germ-line DNA in the same patient. A total of 48 SNPs were identified including 4 novel SNPs when compared with previous resequencing data. For genotype-phenotype association studies, we determined the levels of aromatase activity, estrone, estradiol, and tumor size in patients pre-AI and post-AI treatment. We defined two tightly linked SNPs (rs6493497 and rs7176005 in the 5'-flanking region of CYP19 exon 1.1) that were significantly associated with a greater change in aromatase activity after AI treatment. In a follow-up study of 200 women with early-stage breast cancer who were treated with adjuvant anastrozole, these same two SNPs were also associated with higher plasma estradiol levels in patients pre-AI and post-AI treatment. Electrophoretic mobility shift and reporter gene assays confirmed likely functional effects of these two SNPs on transcription of CYP19. Our findings indicate that two common genetic polymorphisms in the aromatase gene CYP19 vary the response of breast cancer patients to aromatase inhibitors. Cancer Res; 70(1); 319–28

Abstract Prostate cancer, a complex disease, can be relatively harmless or extremely aggressive. To identify candidate genes involved in causal pathways of aggressive prostate cancer, we implemented a systems biology approach by combining differential expression analysis and coexpression network analysis to evaluate transcriptional profiles using lymphoblastoid cell lines from 62 prostate cancer patients with aggressive phenotype (Gleason grade ≥ 8) and 63 prostate cancer patients with nonaggressive phenotype (Gleason grade ≤ 5). From 13,935 mRNA genes and 273 microRNAs (miRNA) tested, we identified significant differences in 1,100 mRNAs and 7 miRNAs with a false discovery rate (FDR) of <0.01. We also identified a coexpression module demonstrating significant association with the aggressive phenotype of prostate cancer (P = 3.67 × 10−11). The module of interest was characterized by overrepresentation of cell cycle–related genes (FDR = 3.50 × 10−50). From this module, we further defined 20 hub genes that were highly connected to other genes. Interestingly, 5 of the 7 differentially expressed miRNAs have been implicated in cell cycle regulation and 2 (miR-145 and miR-331-3p) are predicted to target 3 of the 20 hub genes. Ectopic expression of these two miRNAs reduced expression of target hub genes and subsequently resulted in cell growth inhibition and apoptosis. These results suggest that cell cycle is likely to be a molecular pathway causing aggressive phenotype of prostate cancer. Further characterization of cell cycle–related genes (particularly, the hub genes) and miRNAs that regulate these hub genes could facilitate identification of candidate genes responsible for the aggressive phenotype and lead to a better understanding of prostate cancer etiology and progression. [Cancer Res 2009;69(24):9490–7]