Citations

AbstractBackgroundTransforming growth factor (TGF)‐β1 produced in airway epithelia has been suggested as a contributor to the airway remodeling observed in asthma patients. The protein tyrosine phosphatase SHP2 is a demonstrable modulator of TGF‐β1 production and thus a potential regulator of airway remodeling.ObjectivesTo define the signal event by which SHP2 regulates asthmatic responses in airway epithelial cells by using a mouse model of experimental OVA‐induced airway remodeling.MethodsThe airways of Shp2flox/flox mice were infected with recombinant adenovirus vectors expressing a Cre recombinase–green fluorescence protein (GFP) fusion protein as part of allergen provocation studies using mice sensitized with ovalbumin (OVA) and repeatedly challenged with OVA. Several endpoint pathologies were assessed, including airway hyper‐responsiveness (AHR), lung inflammatory score, peribronchial collagen deposition, and α‐smooth muscle actin (SMA) hyperplasia. In vitro studies using airway epithelial cells (BEAS‐2B) were used to investigate the role of SHP2 in the regulation of pulmonary remodeling events, including the expression of collagen, α‐SMA, and TGF‐β1.ResultsChronic OVA challenges in wild‐type mice resulted in airway remodeling and lung dysfunction (e.g., increased inflammatory scores, collagen deposition (fibrosis), smooth muscle hyperplasia, and a significant increase in AHR). These endpoint pathology metrics were each significantly attenuated by conditional shp2 gene knockdown in airway epithelia. In vitro studies using BEAS‐2B cells also demonstrated that the level of TGF‐β1 production by these cells correlated with the extent of shp2 gene expression.ConclusionsSHP2 activities in airway epithelial cells appear to modulate TGF‐β1 production and, in turn, regulate allergic airway remodeling following allergen provocation.Clinical ImplicationsOur findings identify SHP2 as a previously underappreciated contributor to the airway remodeling and lung dysfunction associated with allergen challenge. As such, SHP2 represents a potentially novel therapeutic target for the treatment of asthmatics.Capsule summaryAirway epithelial protein tyrosine phosphatase SHP2 appears to modulate TGF‐β1 activities as part of one or more cellular pathways leading to regulating the airway remodeling and lung dysfunction occurring in mouse models of allergic respiratory inflammation.

AbstractMany common genetic variants have been associated with non-Hodgkin lymphoma (NHL), but individual study results are often conflicting. To confirm the role of putative risk alleles in B-cell NHL etiology, we performed a validation genotyping study of 67 candidate single nucleotide polymorphisms within InterLymph, a large international consortium of NHL case-control studies. A meta-analysis was performed on data from 5633 B-cell NHL cases and 7034 controls from 8 InterLymph studies. rs3789068 in the proapoptotic BCL2L11 gene was associated with an increased risk for B-cell NHL (odds ratio = 1.21, P random = 2.21 × 10−11), with similar risk estimates for common B-cell subtypes. PRRC2A rs3132453 in the HLA complex class III region conferred a reduced risk of B-cell NHL (odds ratio = 0.68, P random = 1.07 × 10−9) and was likewise evident for common B-cell subtypes. These results are consistent with the known biology of NHL and provide insights into shared pathogenic components, including apoptosis and immune regulation, for the major B-cell lymphoma subtypes.

Background— The selection of patients with renal artery stenosis (RAS) likely to improve glomerular filtration rate (GFR) after percutaneous transluminal renal angioplasty is difficult. We examined basal hemodynamic and inflammatory factors linked to improved stenotic kidney (STK) function after percutaneous transluminal renal angioplasty in swine RAS. Methods and Results— Fifteen pigs after 6 weeks of hemodynamically significant RAS were studied before and 4 weeks after technically successful percutaneous transluminal renal angioplasty+stenting. STK and contralateral kidney hemodynamics and function were evaluated by multidetector computed-tomography before and after acetylcholine challenge. Single-kidney deoxyhemoglobin (R2*, reciprocal to blood relaxation) and energy-dependent tubular function were assessed using blood-oxygen-level–dependent magnetic resonance imaging before and after furosemide. Baseline renal vein and inferior vena cava levels of inflammatory markers were measured and their gradient and net release calculated. Baseline parameters were compared with normal (n=7) and sham-RAS (n=7) pigs and correlated with the change in STK-GFR after revascularization (ΔGFR). Four weeks after percutaneous transluminal, renal angioplasty blood pressure was normalized in all animals, but STK-GFR improved in 10 of 15 (ΔGFR =+22.0±8.5 mL/min). ΔGFR correlated inversely with basal STK-GFR, renal release of inflammatory markers, and medullary R2* response to furosemide, but directly with GFR response to acetylcholine. Basal contralateral kidney GFR correlated directly with ΔGFR. Conclusions— Low basal STK-GFR with preserved response to acetylcholine may predict benefit from revascularization in RAS, whereas renal inflammation and robust STK-R2* responses to furosemide (possibly reflecting avid tubular oxygen consumption) are associated with less favorable outcomes. These tools may be useful for identification of patients likely to improve renal function after revascularization.

Revascularization improves blood pressure but not renal function in most patients with atherosclerotic renal artery stenosis (ARAS), possibly related to injury incurred during renal reperfusion. Bendavia, a novel tetrapeptide that inhibits mitochondrial permeability transition pore opening, reduces apoptosis, oxidative stress, and ischemia-reperfusion injury in experimental models. However, its potential for improving renal response to revascularization of chronic ARAS is unknown. We hypothesized that adjunct Bendavia would improve renal structure and function after percutaneous transluminal renal angioplasty (PTRA). Pigs were treated after 6 weeks of ARAS or control with PTRA+stenting (or sham), adjunct continuous 4-hour infusion of Bendavia (0.05 mg/kg IV) or vehicle (n=7 each) during PTRA. Single-kidney renal blood flow and glomerular filtration rate were studied 4 weeks later and renal mitochondrial biogenesis, microvascular architecture, and injurious pathways evaluated ex vivo. Monocyte chemoattractant protein-1 levels rose after PTRA, suggesting inflammatory injury. Bendavia did not immediately affect inflammatory cytokine levels, yet 4 weeks later, stenotic kidney renal blood flow and glomerular filtration rate both improved (44.00 ± 0.21% and 36.40 ± 10.21%, respectively) in ARAS+PTRA+Bendavia compared with ARAS+PTRA+vehicle. Renal mitochondrial biogenesis was restored after PTRA+Bendavia, and microvascular rarefaction, apoptosis, oxidative stress, tubular injury, and fibrosis decreased. Infusion of Bendavia during PTRA preserved mitochondrial biogenesis, renal hemodynamics, and function, and attenuated tissue injury in swine ARAS. Thus, functional mitochondrial injury during renal reperfusion may sustain renal inflammatory injury and limit kidney recovery after PTRA. Potent antiapoptotic and antioxidant effects provide Bendavia a novel therapeutic potential for improving kidney outcomes after PTRA in experimental ARAS.

Objective— Endothelial cell (EC) inflammatory status is critical to many vascular diseases. Emerging data demonstrate that mutations of Krüppel-like factor-11 (KLF11), a gene coding maturity-onset diabetes mellitus of the young type 7 ( MODY7 ), contribute to the development of neonatal diabetes mellitus. However, the function of KLF11 in the cardiovascular system still remains to be uncovered. In this study, we aimed to investigate the role of KLF11 in vascular endothelial inflammation. Methods and Results— KLF11 is highly expressed in vascular ECs and induced by proinflammatory stimuli. Adenovirus-mediated KLF11 overexpression inhibits expression of tumor necrosis factors-α–induced adhesion molecules. Moreover, small interfering RNA–mediated KLF11 knockdown augments the proinflammatory status in ECs. KLF11 inhibits promoter activity of adhesion molecules induced by tumor necrosis factor-α and nuclear factor-κB p65 overexpression. Mechanistically, KLF11 potently inhibits nuclear factor-κB signaling pathway via physical interaction with p65. Furthermore, KLF11 knockdown results in increased binding of p65 to vascular cell adhesion molecule-1 and E-selectin promoters. At the whole organism level, KLF11 −/− mice exhibit a significant increase in leukocyte recruitment to ECs after lipopolysaccharide administration. Conclusion— Taken together, our data demonstrate for the first time that KLF11 is a suppressor of EC inflammatory activation, suggesting that KLF11 constitutes a novel potential molecular target for inhibition of vascular inflammatory diseases.

Abstract Purpose: Glioblastoma (GBM), the most common primary brain tumor in adults, presents a high frequency of alteration in the PI3K pathway. Our objectives were to identify a dual PI3K/mTOR inhibitor optimized to cross the blood–brain barrier (BBB) and characterize its brain penetration, pathway modulation in the brain and efficacy in orthotopic xenograft models of GBM. Experimental Design: Physicochemical properties of PI3K inhibitors were optimized using in silico tools, leading to the identification of GNE-317. This compound was tested in cells overexpressing P-glycoprotein (P-gp) or breast cancer resistance protein (BCRP). Following administration to mice, GNE-317 plasma and brain concentrations were determined, and phosphorylated biomarkers (pAkt, p4EBP1, and pS6) were measured to assess PI3K pathway suppression in the brain. GNE-317 efficacy was evaluated in the U87, GS2, and GBM10 orthotopic models of GBM. Results: GNE-317 was identified as having physicochemical properties predictive of low efflux by P-gp and BCRP. Studies in transfected MDCK cells showed that GNE-317 was not a substrate of either transporter. GNE-317 markedly inhibited the PI3K pathway in mouse brain, causing 40% to 90% suppression of the pAkt and pS6 signals up to 6-hour postdose. GNE-317 was efficacious in the U87, GS2, and GBM10 orthotopic models, achieving tumor growth inhibition of 90% and 50%, and survival benefit, respectively. Conclusions: These results indicated that specific optimization of PI3K inhibitors to cross the BBB led to potent suppression of the PI3K pathway in healthy brain. The efficacy of GNE-317 in 3 intracranial models of GBM suggested that this compound could be effective in the treatment of GBM. Clin Cancer Res; 18(22); 6239–48. ©2012 AACR.

Abstract Cytokines within the tumor microenvironment play an important role in supporting the growth and survival of B-cell malignancies. One such cytokine, IL-21, promotes the growth of myeloma and Hodgkin lymphoma cells while inducing apoptosis in chronic lymphocytic leukemia. However, the biologic significance of IL-21 has not been examined in Waldenstrom macroglobulinemia (WM), a B-cell lymphoma characterized by elevated serum IgM and a lymphoplasmacytic bone marrow infiltrate. We report here on the presence of IL-21 in the bone marrow of patients with WM and have identified activated T cells as the source of this cytokine. We readily detected the IL-21 receptor on malignant WM B cells and show that IL-21 significantly increases both IgM secretion and cellular proliferation of these cells with no effect on viability. IL-21 rapidly induces phosphorylation of STAT3 in WM cells, and treatment of the WM cell line MWCL-1 with a STAT3 inhibitor abolished the IL-21–mediated increases in cellular proliferation and IgM secretion. IL-21 also increased the expression of known STAT3 targets involved in B-cell differentiation, including BLIMP-1, XBP-1, IL-6, and IL-10. Overall, our data indicate that IL-21 in the bone marrow microenvironment significantly affects the biology of WM tumor cells through a STAT3-dependent mechanism.

Abstract Recent molecular and pathologic evidence indicate that high-grade serous carcinomas of the ovary, which are the most common type of epithelial carcinomas, may arise from the distal part of fallopian tubes or tubal carcinoma implants. Oviductal glycoprotein 1 (Ovgp1), a glycosylated protein found in the epithelial cells in the oviduct, is the only specific tubal marker so far. Ovgp1 promoter-driven SV40 large T-antigen transgenic mice develop tumors in the female reproductive organs. To characterize these tumors, we performed immunohistochemical analysis in paraffin-embedded sections. Mice were sacrificed at 8 or 13 weeks old. Macroscopically we observed large tumors in the uterus and cervix and markedly enlarged region in the oviduct. Due to the large tumor in the uterus and cervix, we could not keep the mice longer than 13 weeks. Histologically, there were no major differences in these affected regions between 8 weeks old and 13 weeks old mice. We observed, (i) relatively small ovaries and ovarian follicular hyperplasia, (ii) intact ovarian surface epithelium showing no atypical histology, (iii) atypical epithelial hyperplasia within the oviduct (with endometrioid architectural and cytologic features), (iv) leiomyosarcomatous proliferation in the myometrium, and (v) squamous carcinoma in situ in the cervix or early invasive cervical cancer with extensive papillary architecture. We did not detect metastasis from the tumor to other organs. The atypical abnormalities of the oviduct were more significant in the proximal site to the uterus than the distal site. The proximal oviduct demonstrated weak and spotty p53 expression, beneath the epithelium, similar to p53 signature in the human oviduct. We hypothesized that stem cell components may contribute to the tumor development and that putative cancer stem cells could be identified by stem cell markers. In the oviduct epithelium, Bmi1 expression was not detectable. Cytoplasmic expression of Sox2 was observed in all epithelial cells of the oviduct. There was little correlation between Sox2/Bmi1 staining and p53 staining in the oviduct. Interestingly, Sox2 and Bmi1 staining in the wild-type control mice showed immunoreactive cells interspersed between glandular structures, a pattern similar to previously described label-retaining cells in the endometrium. The expression pattern in Ovgp1-SV40 mice, Bmi1 and Sox2 expression were more obvious in the endometrial stromal area but not in the leiomyosarcoma region, which implies that stem cell components in the endometrial region may support the leiomyosarcoma progression in this mouse model. In conclusion, Ovgp1-SV40 transgenic mouse is a useful model for studies involving fallopian and lower genital tract carcinogenesis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3272. doi:1538-7445.AM2012-3272

Abstract Recent RNA-sequencing studies have identified variant transcripts, fusion transcripts and novel transcripts in cancer. However, little is known about the role of these variant transcripts in tumor development. To identify a specific role of these variant transcripts in tumor development toward chemotherapy resistance, we generated a custom retroviral cDNA expression library from 10 ovarian tumors with resistance to chemotherapy. Retrovirues were generated from the custom library, and they were used to transduced exogenous genes into ovarian cancer cell line A1847, a cell line chosen for its sensitivity to paclitaxel. A1847 cells transduced with retroviruses carrying alkaline phosphatase was used as a control. Transuced cells were selected with 25 nM paclitaxel. 87 clones survived the selection in library-tranduced cells whereas none survived the selection in alkaline phosphatase-tranduced control cells. Forty seven clones survive the secondary screens. Sequence analysis of transduced genes in these surviving clones indicate that 4 paclitaxel-resistant clones contain RABL3 splice variant. Although 195 accessions corresponding to wildtype transcripts are reported in AceView, there is a single accession corresponding to RABL splice variant that we identified in this screen. RNAi-mediated downregulation of RABL3 resulted in enhance sensitivity toward paclitaxel in these resistant clones. Ectopic expression of RABL3 splice variant resulted in increased resistant to paclitaxel. Collectively, these results demonstrate the feasibility of performing functional genetic screens to identify novel splice variants involved in tumor development. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5120. doi:1538-7445.AM2012-5120

Abstract Cholangiocarcinomas are rare but aggressive cancers, with an increasing incidence and a dismal 5-year survival rate of less than 5%. Mutations in the genes encoding isocitrate dehydrogenase, IDH1 and IDH2, have been reported in ∼70% of gliomas, ∼20% of myeloid leukemias, ∼56% of chondrosarcomas, and ∼10% of melanomas. We discovered IDH1 and IDH2 mutations in 29 of 305 (9%) intrahepatic cholangiocarcinomas. Tumors with mutations in IDH1 or IDH2 had lower 5-hydroxymethylcytosine and higher 5-methylcytosine levels, as well as increased dimethylation of histone H3K79. Mutations in IDH1 or IDH2 were independently associated with longer time to recurrence of cholangiocarcinoma in multivariate analysis (p = 0.046). We identified 2,267 genes that were significantly hypermethylated in tumors with mutations in IDH1 or IDH2. Hypermethylated CpG sites were significantly enriched in CpG shores and in the 1500 bp upstream of annotated transcription start sites, suggesting a global regulation of transcriptional potential. Gene expression profiling of 7 IDH1/2-mutant and 20 IDH1/2-wildtype tumors revealed increased expression of citric acid cycle and oxidative phosphorylation enzymes, as well as decreased expression of cytoskeleton organization genes. Integrated analyses of DNA methylation and gene expression identified interleukin-6 and several of its downstream targets as candidates for silencing by DNA methylation. Conclusions: Cholangiocarcinomas with mutations in IDH1 or IDH2 represent a molecular subclass with distinct signaling pathway alterations. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1058. doi:1538-7445.AM2012-1058