In Vivo Renin Activity Imaging in the Kidney of Progeroid Ercc1 Mutant Mice.

Changes in the renin-angiotensin system, known for its critical role in the regulation of blood pressure and sodium homeostasis, may contribute to aging and age-related diseases. While the renin-angiotensin system is suppressed during aging, little is known about its regulation and activity within tissues. However, this knowledge is required to successively treat or prevent renal disease in the elderly. Ercc1 is involved in important DNA repair pathways, and when mutated causes accelerated aging phenotypes in humans and mice. In this study, we hypothesized that unrepaired DNA damage contributes to accelerated kidney failure. We tested the use of the renin-activatable near-infrared fluorescent probe ReninSense680™ in progeroid Ercc1d/- mice and compared renin activity levels in vivo to wild-type mice. First, we validated the specificity of the probe by detecting increased intrarenal activity after losartan treatment and the virtual absence of fluorescence in renin knock-out mice. Second, age-related kidney pathology, tubular anisokaryosis, glomerulosclerosis and increased apoptosis were confirmed in the kidneys of 24-week-old Ercc1d/- mice, while initial renal development was normal. Next, we examined the in vivo renin activity in these Ercc1d/- mice. Interestingly, increased intrarenal renin activity was detected by ReninSense in Ercc1d/- compared to WT mice, while their plasma renin concentrations were lower. Hence, this study demonstrates that intrarenal RAS activity does not necessarily run in parallel with circulating renin in the aging mouse. In addition, our study supports the use of this probe for longitudinal imaging of altered RAS signaling in aging.

Disruption of TTDA results in complete nucleotide excision repair deficiency and embryonic lethality.

The ten-subunit transcription factor IIH (TFIIH) plays a crucial role in transcription and nucleotide excision repair (NER). Inactivating mutations in the smallest 8-kDa TFB5/TTDA subunit cause the neurodevelopmental progeroid repair syndrome trichothiodystrophy A (TTD-A). Previous studies have shown that TTDA is the only TFIIH subunit that appears not to be essential for NER, transcription, or viability. We studied the consequences of TTDA inactivation by generating a Ttda knock-out (Ttda(-/-) ) mouse-model resembling TTD-A patients. Unexpectedly, Ttda(-/-) mice were embryonic lethal. However, in contrast to full disruption of all other TFIIH subunits, viability of Ttda(-/-) cells was not affected. Surprisingly, Ttda(-/-) cells were completely NER deficient, contrary to the incomplete NER deficiency of TTD-A patient-derived cells. We further showed that TTD-A patient mutations only partially inactivate TTDA function, explaining the relatively mild repair phenotype of TTD-A cells. Moreover, Ttda(-/-) cells were also highly sensitive to oxidizing agents. These findings reveal an essential role of TTDA for life, nucleotide excision repair, and oxidative DNA damage repair and identify Ttda(-/-) cells as a unique class of TFIIH mutants.

Stratification based on methylation of TBX2 and TBX3 into three molecular grades predicts progression in patients with pTa-bladder cancer.

The potential risk of recurrence and progression in patients with non-muscle-invasive bladder cancer necessitates followup by cystoscopy. The risk of progression to muscle-invasive bladder cancer is estimated based on the European Organisation of Research and Treatment of Cancer score, a combination of several clinicopathological variables. However, pathological assessment is not objective and reproducibility is insufficient. The use of molecular markers could contribute to the estimation of tumor aggressiveness. We recently demonstrated that methylation of GATA2, TBX2, TBX3, and ZIC4 genes could predict progression in Ta tumors. In this study, we aimed to validate the markers in a large patient set using DNA from formalin-fixed and paraffin-embedded tissue. PALGA: the Dutch Pathology Registry was used for patient selection. We included 192 patients with pTaG1/2 bladder cancer of whom 77 experienced progression. Methylation analysis was performed and log-rank analysis was used to calculate the predictive value of each methylation marker for developing progression over time. This analysis showed better progression-free survival in patients with low methylation rates compared with the patients with high methylation rates for all markers (P<0.001) during a followup of ten-years. The combined predictive effect of the methylation markers was analyzed with the Cox-regression method. In this analysis, TBX2, TBX3, and ZIC4 were independent predictors of progression. On the basis of methylation status of TBX2 and TBX3, patients were divided into three new molecular grade groups. Survival analysis showed that only 8% of patients in the low molecular grade group progressed within 5 years. This was 29 and 63% for the intermediate- and high-molecular grade groups. In conclusion, this new molecular-grade based on the combination of TBX2 and TBX3 methylation is an excellent marker for predicting progression to muscle-invasive bladder cancer in patients with primary pTaG1/2 bladder cancer.

SOCS2 mediates the cross talk between androgen and growth hormone signaling in prostate cancer.

UNLABELLED: Anabolic signals such as androgens and the growth hormone/insulin-like growth factor 1 (GH/IGF-1) axis play an essential role in the normal development of the prostate but also in its malignant transformation. In this study, we investigated the role of suppressor of cytokine signaling 2 (SOCS2) as mediator of the cross talk between androgens and GH signals in the prostate and its potential role as tumor suppressor in prostate cancer (PCa). We observed that SOCS2 protein levels assayed by immunohistochemistry are elevated in hormone therapy-naive localized prostatic adenocarcinoma in comparison with benign tissue. In contrast, however, castration-resistant bone metastases exhibit reduced levels of SOCS2 in comparison with localized or hormone naive, untreated metastatic tumors. In PCa cells, SOCS2 expression is induced by androgens through a mechanism that requires signal transducer and activator of transcription 5 protein (STAT5) and androgen receptor-dependent transcription. Consequentially, SOCS2 inhibits GH activation of Janus kinase 2, Src and STAT5 as well as both cell invasion and cell proliferation in vitro. In vivo, SOCS2 limits proliferation and production of IGF-1 in the prostate in response to GH. Our results suggest that the use of GH-signaling inhibitors could be of value as a complementary treatment for castration-resistant PCa. SUMMARY: Androgen induced SOCS2 ubiquitin ligase expression and inhibited GH signaling as well as cell proliferation and invasion in PCa, whereas reduced SOCS2 was present in castration-resistant cases. GH-signaling inhibitors might be a complementary therapeutic option for advanced PCa.

Age-related neuronal degeneration: complementary roles of nucleotide excision repair and transcription-coupled repair in preventing neuropathology.

Neuronal degeneration is a hallmark of many DNA repair syndromes. Yet, how DNA damage causes neuronal degeneration and whether defects in different repair systems affect the brain differently is largely unknown. Here, we performed a systematic detailed analysis of neurodegenerative changes in mouse models deficient in nucleotide excision repair (NER) and transcription-coupled repair (TCR), two partially overlapping DNA repair systems that remove helix-distorting and transcription-blocking lesions, respectively, and that are associated with the UV-sensitive syndromes xeroderma pigmentosum (XP) and Cockayne syndrome (CS). TCR-deficient Csa(-/-) and Csb(-/-) CS mice showed activated microglia cells surrounding oligodendrocytes in regions with myelinated axons throughout the nervous system. This white matter microglia activation was not observed in NER-deficient Xpa(-/-) and Xpc(-/-) XP mice, but also occurred in Xpd(XPCS) mice carrying a point mutation (G602D) in the Xpd gene that is associated with a combined XPCS disorder and causes a partial NER and TCR defect. The white matter abnormalities in TCR-deficient mice are compatible with focal dysmyelination in CS patients. Both TCR-deficient and NER-deficient mice showed no evidence for neuronal degeneration apart from p53 activation in sporadic (Csa(-/-), Csb(-/-)) or highly sporadic (Xpa(-/-), Xpc(-/-)) neurons and astrocytes. To examine to what extent overlap occurs between both repair systems, we generated TCR-deficient mice with selective inactivation of NER in postnatal neurons. These mice develop dramatic age-related cumulative neuronal loss indicating DNA damage substrate overlap and synergism between TCR and NER pathways in neurons, and they uncover the occurrence of spontaneous DNA injury that may trigger neuronal degeneration. We propose that, while Csa(-/-) and Csb(-/-) TCR-deficient mice represent powerful animal models to study the mechanisms underlying myelin abnormalities in CS, neuron-specific inactivation of NER in TCR-deficient mice represents a valuable model for the role of NER in neuronal maintenance and survival.

Hypermethylation of the polycomb group target gene PCDH7 in bladder tumors from patients of all ages.

PURPOSE: Bladder tumors in patients younger than 20 years show a low incidence of the genetic and epigenetic aberrations typically found in older patients. One of the most common epigenetic aberrations in human malignancies is DNA hypermethylation. Polycomb group complexes have an important role during lineage choices in embryogenesis and their target genes are 12 times more likely to be methylated than nonpolycomb group target genes. We hypothesized that methylation of polycomb group target genes is an early event in urothelial carcinogenesis and thus might be observed in young patients. MATERIALS AND METHODS: We stratified 167 patients by age into 4 groups, including age less than 20 years in 14, 20 to 40 in 48, 40 to 60 in 47 and greater than 60 in 58. Five previously identified polycomb group target genes (MEIS1, ONECUT2, OTX1, PCDH7 and SOX21) were selected for methylation analysis. Methylation ratios were calculated by using the unmethylated and methylated signal. The outcome represented the fraction of methylated cells within one tumor. Genes with similar methylation ratios in all age groups were considered as potential bladder cancer initiating candidates. RESULTS: Three genes showed higher methylation ratios in tumors from older patients, including ONECUT2, SOX21 and OTX1 (each p <0.001). MEIS1 showed a similar methylation ratio in all groups but the median methylation ratio was low. PCDH7 showed a similar median methylation percent in all age categories, ie 54% at less than 20, 59% at 20 to 40, 59% at 40 to 60 and 67% at greater than 60 years (p = 0.1). CONCLUSIONS: Tumors from young patients showed less methylation for most markers. PCDH7 showed high methylation ratios in all age categories. Therefore, it could have an important role in early urothelial carcinogenesis.

Targeting a single mismatched minor histocompatibility antigen with tumor-restricted expression eradicates human solid tumors.

Regressions of metastatic solid tumors after allogeneic human leukocyte antigen (HLA)-matched stem cell transplantation (SCT) are often associated with detrimental graft-versus-host disease (GVHD). The graft-versus-host reaction of the HLA-matched donor is directed mainly against the multiple mismatched minor histocompatibility antigens (mHags) of the patient. mHags are strong HLA-restricted alloantigens with differential tissue distribution. Ubiquitously expressed mHags are the prime in situ targets of GVHD. The mHag HA-1 is hematopoiesis restricted, but displays additionally an aberrant expression on solid tumors. Thus, HA-1 might be an excellent target to boost the anti-solid tumor effect of allogeneic SCT without inducing severe GVHD. Here, we show that cytotoxic T lymphocytes (CTLs) solely targeting the human mHag HA-1 are capable of eradicating 3-dimensional human solid tumors in a highly mHag-specific manner in vitro, accompanied by interferon-gamma release. In vivo, HA-1-specific CTLs distribute systemically and prevent human breast cancer metastases in immunodeficient mice. Moreover, HA-1-specific CTLs infiltrate and inhibit the progression of fully established metastases. Our study provides the first proof for the efficacy of a clinically applicable concept to exploit single mismatched mHags with hematopoiesis- and solid tumor-restricted expression for boosting the anti-solid tumor effect of allogeneic SCT.

The development of multiple bladder tumour recurrences in relation to the FGFR3 mutation status of the primary tumour.

Non-muscle invasive bladder cancers (NMI-BCs) represent 75% of bladder cancers upon presentation. After removal of the primary tumour by transurethral resection, multiple recurrences continue to develop in 70% of patients. Consequently, prolonged and costly surveillance by cystoscopy is required. Mutations in the FGFR3 oncogene are common in NMI-BCs and are associated with a lower chance of progression to muscle-invasive disease. Here we analysed the consistency of FGFR3 mutations in primary and recurrent tumours. This knowledge is of crucial importance if FGFR3 mutation analysis on urinary cells is to be used as an alternative for cystoscopical surveillance. To this end, we monitored the disease process and FGFR3 mutation status of primary and recurrent tumours in 118 patients with NMI-BC. During median follow-up of 8.8 years, these patients underwent 2133 cystoscopies and 80 patients developed 414 recurrences. FGFR3 mutations were equally prevalent in primary and recurrent tumours (63%). Patients can have different types of FGFR3 mutations in different tumours. Recurrence risk was not significantly different for patients with a mutant or wild-type primary tumour. Recurrence rates varied widely between patients but were constant for a patient and were unrelated to FGFR3 status. In the mutant patient group, in contrast to the wild-type group, recurrences continued to develop after 10 years. In 81% of the recurrences of patients with a mutant primary tumour, a mutation was found. Moreover, recurrences in this patient group were of lower stage and grade than those of patients with a wild-type primary tumour (p < 0.001). These results suggest that surveillance by FGFR3 mutation analysis on voided urine in combination with a reduced cystoscopy frequency of patients presenting with an FGFR3 mutant tumour is worth investigating.

In-depth investigation of the molecular pathogenesis of bladder cancer in a unique 26-year old patient with extensive multifocal disease: a case report.

BACKGROUND: The molecular characteristics and the clinical disease course of bladder cancer (BC) in young patients remain largely unresolved. All patients are monitored according to an intensive surveillance protocol and we aim to gain more insight into the molecular pathways of bladder tumors in young patients that could ultimately contribute to patient stratification, improve patient quality of life and reduce associated costs. We also determined whether a biomarker-based surveillance could be feasible. CASE PRESENTATION: We report a unique case of a 26-year-old Caucasian male with recurrent non-muscle invasive bladder tumors occurring at a high frequency and analyzed multiple tumors (maximal pTaG2) and urine samples of this patient. Analysis included FGFR3 mutation detection, FGFR3 and TP53 immunohistochemistry, mircosatellite analysis of markers on chromosomes 8, 9, 10, 11 and 17 and a genome wide single nucleotide polymorphism-array (SNP). All analyzed tumors contained a mutation in FGFR3 and were associated with FGFR3 overexpression. None of the tumors showed overexpression of TP53. We found a deletion on chromosome 9 in the primary tumor and this was confirmed by the SNP-array that showed regions of loss on chromosome 9. Detection of all recurrences was possible by urinary FGFR3 mutation analysis. CONCLUSIONS: Our findings would suggest that the BC disease course is determined by not only a patient's age, but also by the molecular characteristics of a tumor. This young patient contained typical genetic changes found in tumors of older patients and implies a clinical disease course comparable to older patients. We demonstrate that FGFR3 mutation analysis on voided urine is a simple non-invasive method and could serve as a feasible follow-up approach for this young patient presenting with an FGFR3 mutant tumor.

Sox2 is important for two crucial processes in lung development: branching morphogenesis and epithelial cell differentiation.

The primary lung bud originates from the foregut and develops into the bronchial tree by repetitive branching and outgrowing of the airway. The Sry related HMG box protein Sox2 is expressed in a cyclic manner during initiation and branching morphogenesis of the lung. It is highly expressed in non-branching regions and absent from branching regions, suggesting that downregulation of Sox2 is mandatory for airway epithelium to respond to branch inducing signals. Therefore, we developed transgenic mice that express a doxycycline inducible Sox2 in the airway epithelium. Continuous expression of Sox2 hampers the branching process resulting in a severe reduction of the number of airways. In addition, the bronchioli transiently go over into enlarged, alveolar-like airspaces, a pathology described as bronchiolization of alveoli. Furthermore, a substantial increase was observed of cGRP positive neuroendocrine cells and Delta Np63 isoform expressing (pre-) basal cells, which are both committed precursor-like cells. Thus, Sox2 prevents airways from branching and prematurely drives cells into committed progenitors, apparently rendering these committed progenitors unresponsive to branch inducing signals. However, Sox2 overexpression does not lead to a complete abrogation of the epithelial differentiation program.

Perturbations of vascular homeostasis and aortic valve abnormalities in fibulin-4 deficient mice.

The Fibulins are a 6-member protein family hypothesized to function as intermolecular bridges that stabilize the organization of extracellular matrix structures. Here, we show that reduced expression of Fibulin-4 leads to aneurysm formation, dissection of the aortic wall and cardiac abnormalities. Fibulin-4 knockdown mice with a hypomorphic expression allele arose from targeted disruption of the adjacent Mus81 endonuclease gene. Mice homozygous for the Fibulin-4 reduced expression allele (Fibulin-4(R/R)) show dilatation of the ascending aorta and a tortuous and stiffened aorta, resulting from disorganized elastic fiber networks. They display thickened aortic valvular leaflets that are associated with aortic valve stenosis and insufficiency. Strikingly, already a modest reduction in expression of Fibulin-4 in the heterozygous Fibulin-4(+/R) mice occasionally resulted in small aneurysm formation. To get insight into the underlying molecular pathways involved in aneurysm formation and response to aortic failure, we determined the aorta transcriptome of Fibulin-4(+/R) and Fibulin-4(R/R) animals and identified distinct and overlapping biological processes that were significantly overrepresented including cytoskeleton organization, cell adhesion, apoptosis and several novel gene targets. Transcriptome and protein expression analysis implicated perturbation of TGF-beta signaling in the pathogenesis of aneurysm in fibulin-4 deficient mice. Our results show that the dosage of a single gene can determine the severity of aneurysm formation and imply that disturbed TGF-beta signaling underlies multiple aneurysm phenotypes.

Changes in the penile arteries of the rat after fractionated irradiation of the prostate: a pilot study.

INTRODUCTION: External beam radiotherapy for prostate cancer leads to erectile dysfunction in 36%-43% of patients. The underlying mechanism is largely unknown, although some clinical studies suggest that the arterial supply to the corpora cavernosa is responsible. Two animal experimental studies reported on the effects of a single fraction of prostate irradiation on the penile structures. However, irradiation in multiple fractions is more representative of the actual clinical treatment. AIM: The present prospective, controlled study was initiated to investigate the effect of fractionated prostate irradiation on the arteries of the corpora cavernosa. MAIN OUTCOME MEASURES: Histological evaluation of the penile tissue in comparison with control rats at 2, 4, and 9 weeks after irradiation. METHODS: The prostate of twelve rats was treated with external beam radiation in 5 daily fractions of 7.4 gray. Three control rats were treated with sham irradiation. Prostatic and penile tissue was evaluated for general histology (hematoxylin-eosin). The penile tissue was further evaluated after combined staining for collagen (resorcin fuchsin) and alpha-smooth muscle actin (SMA) (Biogenex). RESULTS: The prostate showed adequate irradiation with fibrosis occurring at 9 weeks after irradiation. The corpora cavernosa showed arteries that had developed loss of smooth muscle cells expressing SMA, thickening of the intima, and occlusions. All the control rats maintained normal anatomy. CONCLUSION: This is the first animal experimental study that demonstrates changes in the arteries of the corpora cavernosa after fractionated irradiation to the prostatic area. The preliminary data suggests that erectile dysfunction after radiotherapy might be caused by radiation damage to the arterial supply of the corpora cavernosa.

Stimulated neovascularization, inflammation resolution and collagen maturation in healing rat cutaneous wounds by a heparan sulfate glycosaminoglycan mimetic, OTR4120.

Heparan sulfate glycosaminoglycans (HS-GAGs) are not only the structural elements of tissue architecture but also regulate the bioavailability and transduction pathways of heparan sulfate-bound polypeptides released by cells or the extracellular matrix. Heparan sulfate-bound polypeptides include inflammatory mediators, chemokines, angiogenic factors, morphogens, and growth-promoting factors that induce cell migration, proliferation, and differentiation in wound healing. OTR4120, a polymer engineered to mimic the properties of HS-GAGs, is used to replace the natural HS-GAGs that are degraded during wound repair, and enhance the tissue regeneration by preserving the cellular microenvironment and the endogenous signals needed for tissue regeneration. We previously demonstrated that OTR4120 treatment had a long-term effect on increasing breaking strength and vasodilation in healing rat full-thickness excisional wounds. The present study investigates the underlying mechanisms of the effects of OTR4120 treatment in improving the quality of cutaneous wound repair. We found that OTR4120 treatment stimulated inflammation resolution and increased neovascularization. OTR4120 treatment also promoted epidermal migration and proliferation during reepithelialization. Moreover, the granulation tissue formation and collagen maturation were improved in OTR4120-treated wounds. Three months after wounding, the effects of OTR4120 treatment on vascularization and inflammation resolution were normalized, except for an improved neodermis. We conclude that OTR4120 is a potential matrix therapeutic agent that ensures the quality of normal cutaneous wound repair and may restore impaired wound healing characterized by deficient angiogenesis and prolonged inflammation.

Targeted disruption of the Mn1 oncogene results in severe defects in development of membranous bones of the cranial skeleton.

Fusion of the MN1 gene to TEL (ETV6) results in myeloid leukemia. The fusion protein combines the transcription activating domain of MN1 and the DNA binding domain of TEL and is thought to act as a deranged transcription factor. In addition, disruption of the large first exon of the MN1 gene is thought to inactivate MN1 function in a meningioma. To further investigate the role of MN1 in cancer, we generated Mn1 knockout mice. Mn1(+/-) animals were followed for 30 months, but they had no higher incidence of tumor formation than wild-type littermates. Mn1 null mice, however, were found to die at birth or shortly thereafter as the result of a cleft palate. Investigation of newborn or embryonic day 15.5 (E15.5) to E17.5 null mice revealed that the development of several bones in the skull was abnormal. The affected bones are almost exclusively formed by intramembranous ossification. They are either completely agenic at birth (alisphenoid and squamosal bones and vomer), hypoplastic, deformed (basisphenoid, pterygoid, and presphenoid), or substantially thinner (frontal, parietal, and interparietal bones). In heterozygous mice hypoplastic membranous bones and incomplete penetrance of the cleft palate were observed. We conclude that Mn1 is an important factor in development of membranous bones.

RGTA OTR 4120, a heparan sulfate proteoglycan mimetic, increases wound breaking strength and vasodilatory capability in healing rat full-thickness excisional wounds.

ReGeneraTing Agents (RGTAs), a family of polymers engineered to protect and stabilize heparin-binding growth factors, have been shown to promote tissue repair and regeneration. In this study, the effects of one of these polymers, RGTA OTR4120, on healing of full-thickness excisional wounds in rats were investigated. Two 1.5 cm diameter circular full-thickness excisional wounds were created on the dorsum of a rat. After creation of the wounds, RGTA OTR4120 was applied. The progress of healing was assessed quantitatively by evaluating the wound closure rate, vasodilatory capability, and wound breaking strength. The results showed a triple increase of the local vascular response to heat provocation in the RGTA OTR4120-treated wounds as compared with vehicle-treated wounds. On days 14 and 79 after surgery, the wounds treated with RGTA OTR4120 gained skin strength 12% and 48% of the unwounded skin, respectively, and displayed a significantly increased gain in skin strength when compared with control animals. These results raise the possibility of efficacy of RGTA OTR4120 in accelerating surgically cutaneous wound healing by enhancing the wound breaking strength and improving the microcirculation.

Decreased mitochondrial respiration in aneurysmal aortas of Fibulin-4 mutant mice is linked to PGC1A regulation.

Aim: Thoracic aortic aneurysms are a life-threatening condition often diagnosed too late. To discover novel robust biomarkers, we aimed to better understand the molecular mechanisms underlying aneurysm formation. Methods and results: In Fibulin-4R/R mice, the extracellular matrix protein Fibulin-4 is 4-fold reduced, resulting in progressive ascending aneurysm formation and early death around 3 months of age. We performed proteomics and genomics studies on Fibulin-4R/R mouse aortas. Intriguingly, we observed alterations in mitochondrial protein composition in Fibulin-4R/R aortas. Consistently, functional studies in Fibulin-4R/R vascular smooth muscle cells (VSMCs) revealed lower oxygen consumption rates, but increased acidification rates. Yet, mitochondria in Fibulin-4R/R VSMCs showed no aberrant cytoplasmic localization. We found similar reduced mitochondrial respiration in Tgfbr-1M318R/+ VSMCs, a mouse model for Loeys-Dietz syndrome (LDS). Interestingly, also human fibroblasts from Marfan (FBN1) and LDS (TGFBR2 and SMAD3) patients showed lower oxygen consumption. While individual mitochondrial Complexes I-V activities were unaltered in Fibulin-4R/R heart and muscle, these tissues showed similar decreased oxygen consumption. Furthermore, aortas of aneurysmal Fibulin-4R/R mice displayed increased reactive oxygen species (ROS) levels. Consistent with these findings, gene expression analyses revealed dysregulation of metabolic pathways. Accordingly, blood ketone levels of Fibulin-4R/R mice were reduced and liver fatty acids were decreased, while liver glycogen was increased, indicating dysregulated metabolism at the organismal level. As predicted by gene expression analysis, the activity of PGC1α, a key regulator between mitochondrial function and organismal metabolism, was downregulated in Fibulin-4R/R VSMCs. Increased TGFß reduced PGC1α levels, indicating involvement of TGFß signalling in PGC1α regulation. Activation of PGC1α restored the decreased oxygen consumption in Fibulin-4R/R VSMCs and improved their reduced growth potential, emphasizing the importance of this key regulator. Conclusion: Our data indicate altered mitochondrial function and metabolic dysregulation, leading to increased ROS levels and altered energy production, as a novel mechanism, which may contribute to thoracic aortic aneurysm formation.

Targeted biallelic inactivation of Pten in the mouse prostate leads to prostate cancer accompanied by increased epithelial cell proliferation but not by reduced apoptosis.

The PTEN tumor suppressor gene is frequently inactivated in human tumors, including prostate cancer. Based on the Cre/loxP system, we generated a novel mouse prostate cancer model by targeted inactivation of the Pten gene. In this model, Cre recombinase was expressed under the control of the prostate-specific antigen (PSA) promoter. Conditional biallelic and monoallelic Pten knock-out mice were viable and Pten recombination was prostate-specific. Mouse cohorts were systematically characterized at 4 to 5, 7 to 9, and 10 to 14 months. A slightly increased proliferation rate of epithelial cells was observed in all prostate lobes of monoallelic Pten knock-out mice (PSA-Cre;Pten-loxP/+), but minimal pathologic changes were detected. All homozygous knock-out mice (PSA-Cre;Pten-loxP/loxP) showed an increased size of the luminal epithelial cells, large areas of hyperplasia, focal prostate intraepithelial neoplasia lesions and an increased prostate weight at 4 to 5 months. More extensive prostate intraepithelial neoplasia and focal microinvasion occurred at 7 to 9 months; invasive prostate carcinoma was detected in all male PSA-Cre;Pten-loxP/loxP mice at 10 to 14 months. At 15 to 16 months, a rare lymph node metastasis was found. In hyperplastic cells and in tumor cells, the expression of phospho-AKT was up-regulated. In hyperplastic and tumor cells, expression of luminal epithelial cell cytokeratins was up-regulated; tumor cells were negative for basal epithelial cell cytokeratins. Androgen receptor expression remained detectable at all stages of tumor development. The up-regulation of phospho-AKT correlated with an increased proliferation rate of the epithelial cells, but not with a reduced apoptosis.

Human Microtumors Generated in 3D: Novel Tools for Integrated In Situ Studies of Cancer Immunotherapies.

Cellular immunotherapy targeting human tumor antigens is a promising strategy to treat solid tumors. Yet clinical results of cellular immunotherapy are disappointing. Moreover, the currently available in vitro human tumor models are not designed to study the optimization of T-cell therapies of solid tumors. Here, we describe a novel assay for multiparametric in situ analysis of therapeutic effects on individual human three-dimensional (3D) tumors. In this assay, tumors of several millimeter diameter are generated from human cancer cell lines of different tumor entities in a collagen type I microenvironment. A newly developed approach for efficient morphological analysis reveals that these in vitro tumors resemble many characteristics of the corresponding clinical cancers such as histological features, immunohistochemical staining patterns, distinct tumor growth compartments and heterogeneous protein expression. To assess the response to therapy with tumor antigen specific T-cells, standardized protocols are described to determine T-cell infiltration and tumor destruction by monitoring soluble factors and tumor growth. Human tumors engineered in 3D collagen scaffolds are excellent in vitro surrogates for avascular tumor stages allowing integrated analyses of the antitumor efficacy of cancer specific immunotherapy in situ.

AT1-receptor blockade, but not renin inhibition, reduces aneurysm growth and cardiac failure in fibulin-4 mice.

AIMS: Increasing evidence supports a role for the angiotensin II-AT1-receptor axis in aneurysm development. Here, we studied whether counteracting this axis via stimulation of AT2 receptors is beneficial. Such stimulation occurs naturally during AT1-receptor blockade with losartan, but not during renin inhibition with aliskiren. METHODS AND RESULTS: Aneurysmal homozygous fibulin-4 mice, displaying a four-fold reduced fibulin-4 expression, were treated with placebo, losartan, aliskiren, or the ß-blocker propranolol from day 35 to 100. Their phenotype includes cystic media degeneration, aortic regurgitation, left ventricular dilation, reduced ejection fraction, and fractional shortening. Although losartan and aliskiren reduced hemodynamic stress and increased renin similarly, only losartan increased survival. Propranolol had no effect. No drug rescued elastic fiber fragmentation in established aneurysms, although losartan did reduce aneurysm size. Losartan also increased ejection fraction, decreased LV diameter, and reduced cardiac pSmad2 signaling. None of these effects were seen with aliskiren or propranolol. Longitudinal micro-CT measurements, a novel method in which each mouse serves as its own control, revealed that losartan reduced LV growth more than aneurysm growth, presumably because the heart profits both from the local (cardiac) effects of losartan and its effects on aortic root remodeling. CONCLUSION: Losartan, but not aliskiren or propranolol, improved survival in fibulin-4 mice. This most likely relates to its capacity to improve structure and function of both aorta and heart. The absence of this effect during aliskiren treatment, despite a similar degree of blood pressure reduction and renin-angiotensin system blockade, suggests that it might be because of AT2-receptor stimulation.

Cell type-specific hypersensitivity to oxidative damage in CSB and XPA mice.

Mutations in the CSB gene cause Cockayne syndrome (CS), a rare inherited disorder, characterized by UV-sensitivity, severe neurodevelopmental and progeroid symptoms. CSB functions in the transcription-coupled repair (TCR) sub-pathway of nucleotide excision repair (NER), responsible for the removal of UV-induced and other helix-distorting lesions from the transcribed strand of active genes. Several lines of evidence support the notion that the CSB TCR defect extends to other non-NER type transcription-blocking lesions, notably various kinds of oxidative damage, which may provide an explanation for part of the severe CS phenotype. We used genetically defined mouse models to examine the relationship between the CSB defect and sensitivity to oxidative damage in different cell types and at the level of the intact organism. The main conclusions are: (1) CSB(-/-) mouse embryo fibroblasts (MEFs) exhibit a clear hypersensitivity to ionizing radiation, extending the findings in genetically heterogeneous human CSB fibroblasts to another species. (2) CSB(-/-) MEFs are highly sensitive to paraquat, strongly indicating that the increased cytotoxicity is due to oxidative damage. (3) The hypersenstivity is independent of genetic background and directly related to the CSB defect and is not observed in totally NER-deficient XPA MEFs. (4) Wild type embryonic stem (ES) cells display an increased sensitivity to ionizing radiation compared to fibroblasts. Surprisingly, the CSB deficiency has only a very minor additional effect on ES cell sensitivity to oxidative damage and is comparable to that of an XPA defect, indicating cell type-specific differences in the contribution of TCR and NER to cellular survival. (5) Similar to ES cells, CSB and XPA mice both display a minor sensitivity to whole-body X-ray exposure. This suggests that the response of an intact organism to radiation is largely determined by the sensitivity of stem cells, rather than differentiated cells. These findings establish the role of transcription-coupled repair in resistance to oxidative damage and reveal a cell- and organ-specific impact of this repair pathway to the clinical phenotype of CS and XP.