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Background: Both caveolin-1 (CAV1) and insulin-like growth factor bindings protein 7 (IGFBP7) have been linked to angiogenesis, insulin-like growth factor (IGF) receptor 1 (IGF-1R) signaling, and the tumor microenvironment. However, CAV1 and IGFBP7 have not yet been adequately characterized and investigated as potential prognostic or treatment-predictive biomarkers at the genomic, transcriptomic, and proteomic level in breast cancer.Methods: CAV1 and IGFBP7 were investigated in two large prospective population-based cohorts: the Breast Cancer and Blood (BC-Blood) cohort and the Sweden Cancerome Analysis Network – Breast (SCAN-B) cohort, which both comprised early-stage breast cancer patients. Additionally, the roles of both CAV1 and IGFBP7 in breast cancer were explored in various public databases. IGFBP7 was further examined in the Investigation of Serial Studies to Predict Your Therapeutic Response with Imaging and Molecular Analysis 2 (I-SPY2), an adaptively randomized phase II clinical trial on neoadjuvant therapy for early-stage breast cancer.Results: In the BC-Blood cohort, the prognostic impact of CAV1 protein expression varied based on its localization, anthropometric factors, and tumor characteristics. Notably, CAV1 protein expression in malignant cells predicted a high incidence of breast cancer events among patients with tumors categorized as low-risk, while also indicating metachronous contralateral disease. Additionally, CAV1 polymorphisms were linked to an elevated risk of locoregional recurrence and contralateral breast cancer. On the other hand, low protein levels of tumor-specific IGFBP7 suggested a favorable prognosis. However, the prognostic significance of high levels of tumor-specific IGFBP7 depended on host factors and treatment. In the SCAN-B cohort, high CAV1 gene expression emerged as an independent prognostic factor in triple-negative breast cancer. Moreover, the molecular profile associated with high CAV1 gene expression implicated a poten

Combining information from the tumor microenvironment (TME) with PAM50 Risk of Recurrence (ROR) score could improve breast cancer prognostication. Caveolin-1 (CAV1) is a marker of an active TME. CAV1 is a membrane protein involved in cell signaling, extracellular matrix organization, and tumor-stroma interactions. We sought to investigate CAV1 gene expression in relation to PAM50 subtypes, ROR score, and their joint prognostic impact. CAV1 expression was compared between PAM50 subtypes and ROR categories in two cohorts (SCAN-B, n = 5326 and METABRIC, n = 1980). CAV1 expression was assessed in relation to clinical outcomes using Cox regression and adjusted for clinicopathological predictors. Effect modifications between CAV1 expression and ROR categories on clinical outcome were investigated using multiplicative and additive two-way interaction analyses. Differential gene expression and gene set enrichment analyses were applied to compare high and low expressing CAV1 tumors. All samples expressed CAV1 with the highest expression in the Normal-like subtype. Gene modules consistent with epithelial-mesenchymal transition (EMT), hypoxia, and stromal activation were associated with high CAV1 expression. CAV1 expression was inversely associated with ROR category. Interactions between CAV1 expression and ROR categories were observed in both cohorts. High expressing CAV1 tumors conferred worse prognosis only within the group classified as ROR high. ROR gave markedly different prognostic information depending on the underlying CAV1 expression. CAV1, a potential mediator between the malignant cells and TME, could be a useful biomarker that enhances and further refines PAM50 ROR risk stratification in patients with ROR high tumors and a potential therapeutic target.

Purpose Caveolin-1 (CAV1) has been implicated in breast cancer oncogenesis and metastasis and may be a potential prognosticator, especially for non-distant events. CAV1 functions as a master regulator of membrane transport and cell signaling. Several CAV1 SNPs have been linked to multiple cancers, but the prognostic impact of CAV1 SNPs in breast cancer remains unclear. Here, we investigated CAV1 polymorphisms in relation to clinical outcomes in breast cancer. Methods A cohort of 1017 breast cancer patients (inclusion 2002–2012, Sweden) were genotyped using Oncoarray by Ilumina. Patients were followed for up to 15 years. Five out of six CAV1 SNPs (rs10256914, rs959173, rs3807989, rs3815412, and rs8713) passed quality control and were used for haplotype construction. CAV1 genotypes and haplotypes in relation to clinical outcomes were assessed with Cox regression and adjusted for potential confounders (age, tumor characteristics, and adjuvant treatments). Results Only one SNP was associated with lymph node status, no other SNPs or haplotypes were associated with tumor characteristics. The CAV1 rs3815412 CC genotype (5.8% of patients) was associated with increased risk of contralateral breast cancer, adjusted hazard ratio (HRadj) 4.26 (95% CI 1.86–9.73). Moreover, the TTACA haplotype (13% of patients) conferred an increased risk for locoregional recurrence HRadj 2.24 (95% CI 1.24–4.04). No other genotypes or haplotypes were associated with clinical outcome. Conclusion CAV1 polymorphisms were associated with increased risk for locoregional recurrence and contralateral breast cancer. These findings may identify patients that could derive benefit from more tailored treatment to prevent non-distant events, if confirmed.

In the mid-1950s, a groundbreaking discovery revealed the fascinating presence of caveolae, referred to as flask-shaped invaginations of the plasma membrane, sparking renewed excitement in the field of cell biology. Caveolae are small, flask-shaped invaginations in the cell membrane that play crucial roles in diverse cellular processes, including endocytosis, lipid homeostasis, and signal transduction. The structural stability and functionality of these specialized membrane microdomains are attributed to the coordinated activity of scaffolding proteins, including caveolins and cavins. While caveolae and caveolins have been long appreciated for their integral roles in cellular physiology, the accumulating scientific evidence throughout the years reaffirms their association with a broad spectrum of human disorders. This review article aims to offer a thorough account of the historical advancements in caveolae research, spanning from their initial discovery to the recognition of caveolin family proteins and their intricate contributions to cellular functions. Furthermore, it will examine the consequences of a dysfunctional caveolar network in the development of human diseases.

Elevating neuroprotective proteins using adeno-associated virus (AAV)-mediated gene delivery shows great promise in combating devastating neurodegenerative diseases. Amyotrophic lateral sclerosis (ALS) is one such disease resulting from loss of upper and lower motor neurons (MNs) with 90-95% of cases sporadic (SALS) in nature. Due to the unknown etiology of SALS, interventions that afford neuronal protection and preservation are urgently needed. Caveolin-1 (Cav-1), a membrane/lipid rafts (MLRs) scaffolding and neuroprotective protein, and MLR-associated signaling components are decreased in degenerating neurons in postmortem human brains. We previously showed that, when crossing our SynCav1 transgenic mouse (TG) with the mutant human superoxide dismutase 1 (hSOD1G93A) mouse model of ALS, the double transgenic mouse (SynCav1 TG/hSOD1G93A) exhibited better motor function and longer survival. The objective of the current study was to test whether neuron-targeted Cav-1 upregulation in the spinal cord using AAV9-SynCav1 could improve motor function and extend longevity in mutant humanized mouse and rat (hSOD1G93A) models of familial (F)ALS. Methods: Motor function was assessed by voluntary running wheel (RW) in mice and forelimb grip strength (GS) and motor evoked potentials (MEP) in rats. Immunofluorescence (IF) microscopy for choline acetyltransferase (ChAT) was used to assess MN morphology. Neuromuscular junctions (NMJs) were measured by bungarotoxin-a (Btx-a) and synaptophysin IF. Body weight (BW) was measured weekly, and the survival curve was determined by Kaplan-Meier analysis. Results: Following subpial gene delivery to the lumbar spinal cord, male and female hSOD1G93A mice treated with SynCav1 exhibited delayed disease onset, greater running-wheel performance, preserved spinal alpha-motor neuron morphology and NMJ integrity, and 10% increased longevity, independent of affecting expression of the mutant hSOD1G93A protein. Cervical subpial SynCav1 delivery to hSOD

Background: Caveolin-1 (CAV1) is associated with cholesterol-rich membrane raft domains and is a master regulator of cell signaling and membrane transport. Here, we investigated CAV1's role in cellular compartments of breast cancer in relation to signaling pathways, clinicopathological features, and clinical outcomes. Methods: CAV1 levels were evaluated with immunohistochemistry in cytoplasm of invasive tumor cells and stromal cells in tumor tissue microarrays from a cohort of 1018 breast cancer patients (inclusion 2002-2012, Sweden). Cytoplasmic and stromal CAV1 were categorized as positive/negative and strong/not strong, respectively. CAV1 expression in relation to clinical outcomes was assessed with Cox regression. Investigations into CAV1 functional pathways was conducted in the STRING, GOBO, and TCGA databases. Results: CAV1 expression was associated with non-luminal subtypes, cell cycle control, inflammation, epithelialmesenchymal transition, and the IGF/Insulin system. Generally, CAV1 was not associated with recurrence risk. Stromal CAV1's impact on recurrence risk was modified by BMI > 25 kg/m(2) (P-interaction = 0.002), waist > 80 cm (P-interaction = 0.005), and invasive tumor size (pT2/3/4) (P-interaction = 0.028). In low-risk patients only, strong stromal CAV1 significantly increased recurrence risk (HRs(adj) > 1.61). In all patients, positive cytoplasmic CAV1 conferred > 2-fold risk for contralateral disease HRadj 2.63 (95% CI 1.36-5.10). Strong stromal CAV1 conferred nearly 2-fold risk for locoregional recurrence HRadj 1.88 (95% CI 1.09-3.24). Conclusions: CAV1's prognostic impact depended on its localization, anthropometric, and tumor factors. Stromal CAV1 predicted high recurrence risk in a group of supposedly "low-risk' patients. Cytoplasmic CAV1 predicted metachronous contralateral disease. If confirmed, CAV1 could be used as treatment target and for risk stratification.

Rationale: Obstructive sleep apnea (OSA) is a common disorder associated with increased risk for cardiovascular disease, diabetes, and premature mortality. There is strong clinical and epidemiologic evidence supporting the importance of genetic factors influencing OSA but limited data implicating specific genes. Objectives: To search for rare variants contributing to OSA severity. Methods: Leveraging high-depth genomic sequencing data from the NHLBI Trans-Omics for Precision Medicine (TOPMed) program and imputed genotype data from multiple population-based studies, we performed linkage analysis in the CFS (Cleveland Family Study), followed by multistage gene-based association analyses in independent cohorts for apnea-hypopnea index (AHI) in a total of 7,708 individuals of European ancestry. Measurements and Main Results: Linkage analysis in the CFS identified a suggestive linkage peak on chromosome 7q31 (LOD = 2.31). Gene-based analysis identified 21 noncoding rare variants in CAV1 (Caveolin-1) associated with lower AHI after accounting for multiple comparisons (P = 7.4 × 10-8). These noncoding variants together significantly contributed to the linkage evidence (P < 10-3). Follow-up analysis revealed significant associations between these variants and increased CAV1 expression, and increased CAV1 expression in peripheral monocytes was associated with lower AHI (P = 0.024) and higher minimum overnight oxygen saturation (P = 0.007). Conclusions: Rare variants in CAV1, a membrane-scaffolding protein essential in multiple cellular and metabolic functions, are associated with higher CAV1 gene expression and lower OSA severity, suggesting a novel target for modulating OSA severity.

Cardiovascular diseases represent the global leading cause of morbidity and mortality. Cardiovascular calcification is the most significant predictor of cardiovascular events, but no therapeutic options exist to prevent or treat mineral formation in the vasculature. The presence of bone-like mineral increases cardiac work required to move blood through systemic circulation and can lead to mechanical stress in atherosclerotic plaques, promoting plaque rupture events that cause heart attacks. Clinical trials correlated bisphosphonates (BiPs), common anti-osteoporosis pharmaceuticals, with contradicting cardiovascular outcomes. Here, we demonstrated the importance of treatment timing in BiP-induced mineral disruption or promotion. We showed that BiPs can alter morphological features of calcifications within the atherosclerotic plaque of hyperlipidemic mice, which may affect plaque rupture risk. Osteogenic differentiation of resident vascular smooth muscle cells (VSMCs) and release of calcifying extracellular vesicles (EVs) mediate cardiovascular calcification, which imitates bone mineralization by osteoblasts. Formation of calcifying EVs by VSMCs requires caveolin-1 (CAV1), a scaffolding membrane protein. Targeting cellular mechanisms that involve CAV1 may represent ideal strategies to develop therapeutics for cardiovascular calcification. We studied the effect of inhibiting several upstream and downstream molecules that are involved in CAV1 activation and trafficking. Interestingly, we showed that altering CAV1 trafficking does not negatively impact physiological mineralization of osteoblasts. We concluded that despite shared mineralization characteristics, the mechanism(s) of bone and vascular calcification is/are distinct. Furthermore, we demonstrated that epidermal growth factor receptor (EGFR) inhibition prevents vascular calcification by mitigating the biogenesis of calcifying EVs. We showed that EGFR inhibition reduces the release of pro-calcific CAV1-positive E

Caveolin-2 is a protein suitable for the study of interactions of caveolins with other proteins and lipids present in caveolar lipid rafts. Caveolin-2 has a lower tendency to associate with high molecular weight oligomers than caveolin-1, facilitating the study of its structural modulation upon association with other proteins or lipids. In this paper, we have successfully expressed and purified recombinant human caveolin-2 using E. coli. The structural changes of caveolin-2 upon interaction with a lipid bilayer of liposomes were characterized using bioinformatic prediction models, circular dichroism, differential scanning calorimetry, and fluorescence techniques. Our data support that caveolin-2 binds and alters cholesterol-rich domains in the membranes through a CARC domain, a type of cholesterol-interacting domain in its sequence. The far UV-CD spectra support that the purified protein keeps its folding properties but undergoes a change in its secondary structure in the presence of lipids that correlates with the acquisition of a more stable conformation, as shown by differential scanning calorimetry experiments. Fluorescence experiments using egg yolk lecithin large unilamellar vesicles loaded with 1,6-diphenylhexatriene confirmed that caveolin-2 adsorbs to the membrane but only penetrates the core of the phospholipid bilayer if vesicles are supplemented with 30% of cholesterol. Our study sheds light on the caveolin-2 interaction with lipids. In addition, we propose that purified recombinant caveolin-2 can provide a new tool to study protein–lipid interactions within caveolae.

Alzheimer's disease (AD) is the most common form of neurodegeneration and cognitive dysfunction in the elderly. Identifying molecular signals that mitigate and reverse neurodegeneration in AD may be exploited therapeutically. Transgenic AD mice (PSAPP) exhibit learning and memory deficits at 9 and 11 months, respectively, with associated decreased expression of caveolin-1 (Cav-1), a membrane/lipid raft (MLR) scaffolding protein necessary for synaptic and neuroplasticity. Neuronal-targeted gene therapy using synapsin-Cav-1 cDNA (SynCav1) was delivered to the hippocampus of PSAPP mice at 3 months using adeno-associated virus serotype 9 (AAV9). Bilateral SynCav1 gene therapy was able to preserve MLRs profile, learning and memory, hippocampal dendritic arbor, synaptic ultrastructure, and axonal myelin content in 9- and 11-month PSAPP mice, independent of reducing toxic amyloid deposits and astrogliosis. Our data indicate that SynCav1 gene therapy may be an option for AD and potentially in other forms of neurodegeneration of unknown etiology.

Macrophages are immune cells that play crucial roles in host defense against pathogens by triggering their exceptional phagocytic and inflammatory functions. Macrophages that reside in healthy tissues also accomplish important tasks to preserve organ homeostasis, including lipid uptake/efflux or apoptotic-cell clearance. Both homeostatic and inflammatory functions of macrophages require the precise stability of lipid-rich microdomains located at the cell membrane for the initiation of downstream signaling cascades. Caveolin-1 (Cav-1) is the main protein responsible for the biogenesis of caveolae and plays an important role in vascular inflammation and atherosclerosis. The Liver X receptors (LXRs) are key transcription factors for cholesterol efflux and inflammatory gene responses in macrophages. Although the role of Cav-1 in cellular cholesterol homeostasis and vascular inflammation has been reported, the connection between LXR transcriptional activity and Cav-1 expression and function in macrophages has not been investigated. Here, using gain and loss of function approaches, we demonstrate that LXR-dependent transcriptional pathways modulate Cav-1 expression and compartmentation within the membrane during macrophage activation. As a result, Cav-1 participates in LXR-dependent cholesterol efflux and the control of inflammatory responses. Together, our data show modulation of the LXR-Cav-1 axis could be exploited to control exacerbated inflammation and cholesterol overload in the macrophage during the pathogenesis of lipid and immune disorders, such as atherosclerosis.

This study sought to determine if reducing dopamine D1 receptor (D1R) expression in the dorsal striatum (DS) via RNA-interference alters methamphetamine self-administration. A lentiviral construct containing a short hairpin RNA (shRNA) was used to knock down D1R expression (D1RshRNA). D1RshRNA in male rats increased responding for methamphetamine (i.v.) under a fixed-ratio schedule in an extended access paradigm, compared to D1R-intact rats. D1RshRNA also produced a vertical shift in a dose-response paradigm and enhanced responding for methamphetamine in a progressive-ratio schedule, generating a drug-vulnerable phenotype. D1RshRNA did not alter responding for sucrose (oral) under a fixed-ratio schedule compared to D1R-intact rats. Western blotting confirmed reduced D1R expression in methamphetamine and sucrose D1RshRNA rats. D1RshRNA reduced the expression of PSD-95 and MAPK-1 and increased the expression of dopamine transporter (DAT) in the DS from methamphetamine, but not sucrose rats. Sucrose density gradient fractionation was performed in behavior-naïve controls, D1RshRNA- and D1R-intact rats to determine the subcellular localization of D1Rs, DAT and D1R signaling proteins. D1Rs, DAT, MAPK-1 and PSD-95 predominantly localized to heavy fractions, and the membrane/lipid raft protein caveolin-1 (Cav-1) and flotillin-1 were distributed equally between buoyant and heavy fractions in controls. Methamphetamine increased localization of PSD-95, Cav-1, and flotillin-1 in D1RshRNA and D1R-intact rats to buoyant fractions. Our studies indicate that reduced D1R expression in the DS increases vulnerability to methamphetamine addiction-like behavior, and this is accompanied by striatal alterations in the expression of DAT and D1R signaling proteins and is independent of the subcellular localization of these proteins.

The blood-brain barrier (BBB) permeability primarily increases in cerebral venules during acute hypertension. Methyl-beta-cyclodextrin (M beta CD), a cholesterol-depleting agent, decreases the expression of caveolins disrupting caveolar structures. We aimed to determine the effects of M beta CD on the BBB permeability of angiotensin (ANG) II-induced hypertensive rats. Three minutes after M beta CD administration (5 mg/kg), acute hypertension was induced by ANG II (60 mu g/kg). Evans blue (EB) and horseradish peroxidase (HRP) tracers were used to assess BBB permeability. Immunohistochemistry for caveolin (Cav)-1 and tight junction protein claudin-5 was performed. EB dye content significantly increased in both cerebral cortices and left hippocampus in M beta CD (P < 0.05), right cerebral cortex and both hippocampi in ANG II (P < 0.05; P < 0.01), and both cerebral cortices and hippocampi in M beta CD plus ANG II groups compared with controls (P < 0.05; P < 0.01). A significant decrease in claudin-5 immunostaining intensity was observed in animals treated with M beta CD compared with controls (P < 0.05). Cav-1 immunostaining intensity increased in ANG II group (P < 0.05). Ultrastructurally, HRP reaction products were observed in endothelial cells of the microvessels in the hippocampus region in M beta CD group while the tracer was mainly localized in astrocytes and neurons in ANG II, and M beta CD plus ANG II groups. The endothelial cells of the venules in the cerebral cortex of the animals in the latter experimental groups also showed an abundance of caveolar vesicles devoid of HRP reaction products. Our results revealed that M beta CD did not provide overall protective effects on BBB integrity in acute hypertension and even led to BBB disruption in normotensive animals.

Proper axonal growth and guidance is essential for neuron differentiation and development. Abnormal neuronal development due to genetic or epigenetic influences can contribute to neurological and mental disorders such as Down syndrome, Rett syndrome, and autism. Identification of the molecular targets that promote proper neuronal growth and differentiation may restore structural and functional neuroplasticity, thus improving functional performance in neurodevelopmental disorders. Using differentiated human neuronal progenitor cells (NPCs) derived from induced pluripotent stem cells (iPSCs), the present study demonstrates that during early stage differentiation of human NPCs, neuron-targeted overexpression constitutively active Rac1 (Rac1CA) and constitutively active Cdc42 (Cdc42CA) enhance expression of P-Cav-1, T-Cav-1, and P-cofilin and increases axonal growth. Similarly, neuron-targeted over-expression of Cav-1 (termed SynCav1) increases axonal development by increasing both axon length and volume. Moreover, inhibition of Cav-1(Y14A) phosphorylation blunts Rac1/Cdc42-mediated both axonal growth and differentiation of human NPCs and SynCav1(Y14A)-treated NPCs exhibited blunted axonal growth. These results suggest that: (1) SynCav1-mediated dendritic and axonal growth in human NPCs is dependent upon P-Cav-1, (2) P-Cav-1 is necessary for proper axonal growth during early stages of neuronal differentiation, and (3) Rac1/Cdc42CA-mediated neuronal growth is in part dependent upon P-Cav-1. In conclusion, Cav-1 phosphorylation is essential for human neuronal axonal growth during early stages of neuronal differentiation.

Rhabdomyosarcoma (RMS) is a pediatric soft tissue tumor classified in two major subtypes namely embryonal and alveolar, which have distinctive histopathological and genetic signatures and worse outcomes in the presence of metastases. Here, in order to evaluate the role of Caveolin-1 (Car-1) in embryonal RMS dissemination, we employed an experimental in vivo metastasis assay using immunodeficient NOD/SCID mice. We found that the intravenous injection of human RD cells engineered for Cav-1 overexpression promoted the formation of lung metastases compared to parental cells. The arisen metastases were isolated and cultured in vitro to establish two derivative lines that showed greater metastatic capacity, as detected by performing in vivo metastasis and tumor spheroid invasion assays. Compared to parental cells, all metastatic lines were characterized by an increase in cell proliferation, migration and invasiveness that were downregulated by synthetic inhibition of Erk pathway. The metastatic cells showed a marked cell apoptosis induced by nutrient deprivation and consistent loss of differentiation characterized by depletion of MyoD and Myogenin factors. Furthermore, they showed marked changes in cell size, a re-organization of the three-dimensional cytoskeleton characterized by an increased actin stress fiber content, and increased adhesion and angiogenic properties. Collectively, these data provide new insights into Cav-1-driven metastatic process of embryonal RMS through cooperation of the Erk signaling pathway. Furthermore, our derivative metastatic lines represent useful tools for identifying genes or molecular pathways that regulate the metastatic progression of embryonal RMS.

Caveolin-1 is a major component protein of the caveolae-a type of flask shaped, 50-100 nm, nonclathrin-coated, microdomain present in the plasma membrane of most mammalian cells. Caveolin-1 functions as a scaffolding protein to organize and concentrate signaling molecules within the caveolae, which may be associated with its unique physicochemical properties including oligomerization, acquisition of detergent insolubility, and association with cholesterol. Here we demonstrate that caveolin-1 is detected in all brain areas examined and recovered in both detergent-soluble and -insoluble fractions. Surprisingly, the recovered molecules from the two different fractions share a similar molecular size ranging from 200 to 2,000 kDa, indicated by gel filtration. Furthermore, both soluble and insoluble caveolin-1 molecules generate a proteinase K (PK)-resistant C-terminal core fragment upon the PK-treatment, by removing ˜36 amino acids from the N-terminus of the protein. Although it recognizes caveolin-1 from A431 cell lysate, an antibody against the C-terminus of caveolin-1 fails to detect the brain protein by Western blotting, suggesting that the epitope in the brain caveolin-1 is concealed. No significant differences in the physicochemical properties of caveolin-1 between uninfected and prion-infected brains are observed.

Karcinom štitne žlezde je najčešće maligno boljenje endokrinih organa. Incidenca tiroidnog kancera je u poslednih trideset godina porasla u gotovo svim regijama u svetu, i ovaj trend zabeležen je i u Srbiji. Citološka analiza uzoraka dobijenih biopsijom tankom iglom (FNAB) omogućava diferencijalnu dijagnostiku ovih lezija, međutim u oko 30% slučajeva daje neodređene rezultate. Pacijenti kojima se ne može postaviti jasna dijagnoza se šalju na dijagnostičku lobektomiju i kod više od trećine operisanih se dijagnostikuje indolentna benigna lezija koja nije zahtevala operativni tretman. Pacijenti sa malignitetom, sa druge strane, bivaju podvrgnuti i drugoj, terapeutskoj operaciji. Postoperativna dijagnostika, iako preciznija, takođe nije bez nedostataka. Kriterijumi koji razdvajaju benigne od malignih lezija folikularne arhitekture nisu jasno definisani. Ovi problemi ukazuju na potrebu za dodatnim testovima, odnosno pomoćnim dijagnostičkim markerima. Dosadašnje studije su analizirale različite proteinske i genetičke markere, kao i njihove kombinacije. Neki od njih su pokazali dobre dijagnostičke performanse. Ipak, različiti nedostaci prate upotrebu ovih markera u klinici - imunohistohemijsko određivanje proteinskih biomarkera podleže subjektivnosti u ocenjivanju, dok korišćenje mutacija kao genetičkih markera pokazuje visoku specifičnost, ali nisku osetljivost jer mnogi karcinomi ne nose mutacije. U ovoj disertaciji su analizirani biomarkeri mereni na nivou DNK, RNK i proteina. Na postoperativnim uzorcima je imunohistohemijski određena ekspresija i tkivna lokalizacija proteina kaveolina-1, kao i prisustvo BRAF V600E. U uzorcima biopsija je pored pomenutih markera, određeno i prisustvo RET/PTC1 i 3 hromozomskih rearanžmana i EGFRvIII mutacije. Ekspresija gena za EGFR je određena u uzorcima grupisanim prema ekspresiji kaveolina-1 i prisustva BRAF V600E mutacije, i analizirane su međusobne korelacije ovih markera, činilaca MAPK signalnog puta. Markeri koji su pokazali dobru, Thyroid cancer is the most common malignancy of the endocrine system. Over the last 30 years the incidence of thyroid cancer has been increasing in almost all regions of the world, and this trend has also been recorded in Serbia. Fine Needle Aspiration Biopsy (FNAB) has enabled preoperative differential diagnosis of these lesions, however, 30% of aspirations yield indeterminate results. Patients with nodules that are not clearly benign or malignant undergo diagnostic lobectomy, and more that a third of them prove to have benign, indolent lesions that did not require surgical treatment. Patients diagnosed with malignancy, on the other hand, are referred to a second, therapeutic surgery. Postoperative diagnosis is more precise, yet, it has drawbacks. The criteria for differentiating benign from malignant lesions with follicular architecture is not well defined. The aforementioned obstacles stress the need for additional tests, i.e. the use of adjunct diagnostic biomarkers. A large number of potential protein and genetic biomarkers, as well as their combinations, has been analysed and some of them proved to have good diagnostic performances. Still, there are obstacles in applying these biomarkers in the clinical setting – immunohistochemical scoring of protein markers is prone to subjective interpretation, while genetic mutation testing, although high in specificity, shows low sensitivity given that many malignant lesions do not bear any known mutations. The aim of this dissertation was the evaluation of potential thyroid cancer biomarkers measured on DNA, RNA and protein level. Postoperative tissue samples were used for immunohistochemical analysis of the expression and tissue localisation of the protein caveolin-1, and determination of the presence of BRAF V600E mutation. Biopsy samples were used for the analysis of the previously mentioned biomarkers, as well as to determine the frequency of RET/PTC1 and 3 chromosomal rearrangements and EGFRvIII mutation. After divi

Schizophrenia is a debilitating psychiatric disorder manifested in early adulthood. Disrupted-in-schizophrenia-1 (DISC1) is a susceptible gene for schizophrenia (Hodgkinson et al. 2004; Millar et al. 2000; St Clair et al. 1990) implicated in neuronal development, brain maturation, and neuroplasticity (Brandon and Sawa 2011; Chubb et al. 2008). Therefore, DISC1 is a promising candidate gene for schizophrenia, but the molecular mechanisms underlying its role in the pathogenesis of the disease are still poorly understood. Interestingly, caveolin-1 (Cav-1), a cholesterol binding and scaffolding protein, regulates neuronal signal transduction and promotes neuroplasticity. In this study we examined the role of Cav-1 in mediating DISC1 expression in neurons in vitro and the hippocampus in vivo. Overexpressing Cav-1 specifically in neurons using a neuron-specific synapsin promoter (SynCav1) increased expression of DISC1 and proteins involved in synaptic plasticity (PSD95, synaptobrevin, synaptophysin, neurexin, and syntaxin 1). Similarly, SynCav1-transfected differentiated human neurons derived from induced pluripotent stem cells (hiPSCs) exhibited increased expression of DISC1 and markers of synaptic plasticity. Conversely, hippocampi from Cav-1 knockout (KO) exhibited decreased expression of DISC1 and proteins involved in synaptic plasticity. Finally, SynCav1 delivery to the hippocampus of Cav-1 KO mice and Cav-1 KO neurons in culture restored expression of DISC1 and markers of synaptic plasticity. Furthermore, we found that Cav-1 coimmunoprecipitated with DISC1 in brain tissue. These findings suggest an important role by which neuron-targeted Cav-1 regulates DISC1 neurobiology with implications for synaptic plasticity. Therefore, SynCav1 might be a potential therapeutic target for restoring neuronal function in schizophrenia.New & noteworthyThe present study is the first to demonstrate that caveolin-1 can regulate DISC1 expression in neuronal models. Furthermore, the

Migration of cancer cells leads to the invasion of distant organs by primary tumors. Further, endogenous electric fields (EFs) in the tumor microenvironment direct the migration of lung cancer cells by a process referred to as electrotaxis - although the precise mechanism remains unclear. Caveolin-1 (Cav-1) is a multifunctional scaffolding protein that is associated with directional cell migration and lung cancer invasion; however, its precise role in lung cancer electrotaxis is unknown. In the present study, we first detected outward electric currents on the tumor body surface in lung cancer xenografts using a highly-sensitive vibrating probe. Next, we found that highly-metastatic H1650-M3 cells migrated directionally to the cathode. In addition, reversal of the EF polarity reversed the direction of migration. Mechanistically, EFs activated Cav-1 and the downstream signaling molecule STAT3. RNA interference of Cav-1 reduced directional cell migration, which was accompanied by dampened STAT3 activation. Furthermore, pharmacological inhibition of STAT3 significantly reduced the electrotactic response, while rescue of STAT3 activation in Cav-1 knock-down cells restored electrotaxis. Taken together, these results suggest that endogenous EFs in the tumor micro-environment might play an important role in lung cancer metastasis by guiding cell migration through a Cav-1/STAT3-mediated signaling pathway.

BackgroundThe pathophysiology of increased severity of erectile dysfunction in men with diabetes and their poor response to oral pharmacotherapy are unclear. Defective vascular endothelium and consequent impairment in the formation and action of nitric oxide (NO) are implicated as potential mechanisms. Endothelial NO synthase, critical for NO generation, is localized to caveolae, plasma membrane lipid rafts enriched in structural proteins, and caveolins. Type 2 diabetes mellitus (T2DM)-induced changes in caveolin expression are recognized to play a role in cardiovascular dysfunction.AimsTo evaluate DM-related changes to male erectile tissue in a mouse model that closely resembles human T2DM and study the specific role of caveolins in penile blood flow and microvascular perfusion using mice lacking caveolin (Cav)-1 or Cav-3.MethodsWe used wild-type C57BL6 (control) and Cav-1 and Cav-3 knockout (KO) male mice. T2DM was induced by streptozotocin followed by a high-fat diet for 4 months. Penile expressions of Cav-1, Cav-3, and endothelial NO synthase were determined by western blot, and phosphodiesterase type 5 activity was measured using [3H] cyclic guanosine monophosphate as a substrate. For hemodynamic studies, Cav-1 and Cav-3 KO mice were anesthetized, and penile blood flow (peak systolic velocity and end-diastolic velocity; millimeters per second) was determined using a high-frequency and high-resolution digital imaging color Doppler system. Penile tissue microcirculatory blood perfusion (arbitrary perfusion units) was measured using a novel PeriCam PSI system.OutcomesPenile erectile tissues were harvested for histologic studies to assess Cav-1, Cav-3, and endothelial NO synthase expression, phosphodiesterase type 5 activity, and blood flow, and perfusion measurements were assessed for hemodynamic studies before and after an intracavernosal injection of prostaglandin E1 (50 ng).ResultsIn T2DM mice, decreased Cav-1 and Cav-3 penile protein expression and increased p

Cancer cells reside in a complex microenvironment comprising stromal cells and immune cells embedded in an extracellular matrix (ECM). Early on in tumor progression, cells reach a critical volume beyond which blood supply is impaired, leading to a decrease in oxygen levels (hypoxia) and nutrient supply. This situation triggers a stress response characterized by a metabolic switch to glycolysis, which will in turn induce acidification of the extracellular environment. Under hypoxia and acidosis, cancer cells adapt their integration of nutrients, signaling molecules, and more generally their exchanges with the extracellular environment not only to survive but also enhance tumor aggressiveness, metastasis and treatment resistance. The overall aim of this thesis was to gain a better understanding of cancer cell adaptive mechanisms in the tumor microenvironment under hypoxic and acidic stress, that could be exploited therapeutically. We focused here on proteoglycan (PG)-dependent uptake mechanisms and cell surface proteins as targets of drug delivery. In paper I, we provided evidence for a role of heparan sulfate PGs in increased uptake of lipoproteins linked to enhanced pro-tumorigenic signaling and acquisition of a lipid droplet loaded phenotype under hypoxia and acidosis, associated with increased tumor-forming capacity. In the follow-up paper II we investigated the functional effects of this phenotype during post-hypoxic stress and found increased tumor aggressiveness, macrophage recruitment and angiogenesis in glioma mouse models, correlating with enhanced expression of pro-angiogenic and pro-tumorigenic factors (e.g. VEGF, HGF, CAIX, VIM) in vitro. In paper III, the global effects of hypoxia on tumor cell surface proteome internalization were studied. We showed downregulation of the surface and internalized proteome at hypoxia, involving caveolin-1 negative regulation of endocytosis. Importantly, we identified several surface proteins that were actively internalize

Cancer stem cells (CSCs) are considered to be responsible for treatment relapse and have therefore become a major target in cancer research. Salinomycin is the most established CSC inhibitor. However, its primary mechanistic target is still unclear, impeding the discovery of compounds with similar anti-CSC activity. Here, we show that salinomycin very specifically interferes with the activity of K-ras4B, but not H-ras, by disrupting its nanoscale membrane organization. We found that caveolae negatively regulate the sensitivity to this drug. On the basis of this novel mechanistic insight, we defined a K-ras-associated and stem cell-derived gene expression signature that predicts the drug response of cancer cells to salinomycin. Consistent with therapy resistance of CSC, 8% of tumor samples in the TCGA-database displayed our signature and were associated with a significantly higher mortality. Using our K-ras-specific screening platform, we identified several new candidate CSC drugs. Two of these, ophiobolin A and conglobatin A, possessed a similar or higher potency than salinomycin. Finally, we established that the most potent compound, ophiobolin A, exerts its K-ras4B-specific activity through inactivation of calmodulin. Our data suggest that specific interference with the K-ras4B/calmodulin interaction selectively inhibits CSC.

Obesity and metabolic syndrome are associated with several cancers, however, the molecular mechanisms remain to be fully elucidated. Recent studies suggest that hypercholesterolemia increases intratumoral androgen signaling in prostate cancer, but it is unclear whether androgenindependent mechanisms also exist. Since hypercholesterolemia is associated with advanced, castrate-resistant prostate cancer, in this study, we aimed to determine whether and how hypercholesterolemia affects prostate cancer progression in the absence of androgen signaling. We demonstrate that diet-induced hypercholesterolemia promotes orthotopic xenograft PC-3 cell metastasis, concomitant with elevated expression of caveolin-1 and IQGAP1 in xenograft tumor tissues. In vitro cholesterol treatment of PC-3 cells stimulated migration and increased IQGAP1 and caveolin-1 protein level and localization to a detergent-resistant fraction. Down-regulation of caveolin-1 or IQGAP1 in PC-3 cells reduced migration and invasion in vitro, and hypercholesterolemia-induced metastasis in vivo. Double knock-down of caveolin-1 and IQGAP1 showed no additive effect, suggesting that caveolin-1 and IQGAP1 act via the same pathway. Taken together, our data show that hypercholesterolemia promotes prostate cancer metastasis independent of the androgen pathway, in part by increasing IQGAP1 and caveolin-1. These results have broader implications for managing metastasis of cancers in general as IQGAP1 and hypercholesterolemia are implicated in the progression of several cancers.

Caveolin-1 has a complex role in prostate cancer and has been suggested to be a potential biomarker and therapeutic target. As mature caveolin-1 resides in caveolae, invaginated lipid raft domains at the plasma membrane, caveolae have been suggested as a tumor-promoting signaling platform in prostate cancer. However, caveola formation requires both caveolin-1 and cavin-1 (also known as PTRF; polymerase I and transcript release factor). Here, we examined the expression of cavin-1 in prostate epithelia and stroma using tissue microarray including normal, non-malignant and malignant prostate tissues. We found that caveolin-1 was induced without the presence of cavin-1 in advanced prostate carcinoma, an expression pattern mirrored in the PC-3 cell line. In contrast, normal prostate epithelia expressed neither caveolin-1 nor cavin-1, while prostate stroma highly expressed both caveolin-1 and cavin-1. Utilizing PC-3 cells as a suitable model for caveolin-1-positive advanced prostate cancer, we found that cavin-1 expression in PC-3 cells inhibits anchorage-independent growth, and reduces in vivo tumor growth and metastasis in an orthotopic prostate cancer xenograft mouse model. The expression of α-smooth muscle actin in stroma along with interleukin-6 (IL-6) in cancer cells was also decreased in tumors of mice bearing PC-3-cavin-1 tumor cells. To determine whether cavin-1 acts by neutralizing caveolin-1, we expressed cavin-1 in caveolin-1-negative prostate cancer LNCaP and 22Rv1 cells. Caveolin-1 but not cavin-1 expression increased anchorage-independent growth in LNCaP and 22Rv1 cells. Cavin-1 co-expression reversed caveolin-1 effects in caveolin-1-positive LNCaP cells. Taken together, these results suggest that caveolin-1 in advanced prostate cancer is present outside of caveolae, because of the lack of cavin-1 expression. Cavin-1 expression attenuates the effects of non-caveolar caveolin-1 microdomains partly via reduced IL-6 microenvironmental function. With circulatin

Much evidence highlights the importance of polyamines for VSMC (vascular smooth muscle cell) proliferation and migration. Cav-1 (caveolin-1) was recently reported to regulate polyamine uptake in intestinal epithelial cells. The aim of the present study was to assess the importance of Cav-1 for VSMC polyamine uptake and its impact on cell proliferation and migration. Cav-1 KO (knockout) mouse aortic cells showed increased polyamine uptake and elevated proliferation and migration compared with WT (wild-type) cells. Both Cav-1 KO and WT cells expressed the smooth muscle differentiation markers SM22 and calponin. Cell-cycle phase distribution analysis revealed a higher proportion of Cav-1 KO than WT cells in the S phase. Cav-1 KO cells were hyper-proliferative in the presence but not in the absence of extracellular polyamines, and, moreover, supplementation with exogenous polyamines promoted proliferation in Cav-1 KO but not in WT cells. Expression of the solute carrier transporters Slc7a1 and Slc43a1 was higher in Cav-1 KO than in WT cells. ODC (ornithine decarboxylase) protein and mRNA expression as well as ODC activity were similar in Cav-1 KO and WT cells showing unaltered synthesis of polyamines in Cav-1 KO cells. Cav-1 was reduced in migrating cells in vitro and in carotid lesions in vivo. Our data show that Cav-1 negatively regulates VSMC polyamine uptake and that the proliferative advantage of Cav-1 KO cells is critically dependent on polyamine uptake. We provide proof-of-principle for targeting Cav-1-regulated polyamine uptake as a strategy to fight unwanted VSMC proliferation as observed in restenosis.

Im Fokus der Dissertation stand die Evaluierung molekularer Möglichkeiten zur Findung geeigneter Biomarker für das Prostatakarzinom (PCa). Zunächst wurde die epigenetische Promotormethylierung der Gene GSTP1, RARbeta2, APC und PITX2 im Hinblick eines möglichen Methylierungsfeldeffektes untersucht. Die RARβ2-Promotormethylierung konnte als potentieller Marker zur Tumorvorhersage im histologisch normal erscheinenden Gewebe bestimmt werden. GSTP1 zeigte eine äußerst spezifische Tumormethylierung, was dessen diagnostisches Potenzial unterstreicht. Die Methylierung korrelierte zudem mit pathologischen Parametern. Ein Screening im Array-Format identifizierte weitere Gene, deren Promotormethylierung diagnostisch interessant sein könnten. Des Weiteren wurden Genexpressionsanalysen angiogenetischer und Endothel-assoziierter Faktoren durchgeführt, deren diagnostische und prognostische Aussagekraft für das PCa ermittelt wurden. Dabei konnte für Caveolin-1 (CAV1) eine signifikante Herunterregulierung der mRNA-Menge im Tumor gezeigt werden. Die Bisulfit-Sequenzierung von sieben CpG-Dinukleotiden im CAV1-Promotor ergab zwischen Tumor- und tumorangrenzendem Gewebe differenzielle Methylierungsmuster, die zu einer verminderten CAV1-Transkription führen könnten. Zudem führte eine 5-Aza-2-desoxycytidin-Behandlung der CAV1-defizienten LNCaP-Zelllinie zur Reexpression. Weiterhin assoziierte CAV1 invers mit pathologischen Parametern und zeigte prognostische und diagnostische Relevanz. Immunhistologisch wurde CAV1 z.T. deutlich verringert in Endothelzellen und Fibroblasten des Tumors nachgewiesen. Ko-Kultivierungsversuche von HUVEC mit konditionierten Zellmedien ergaben z.T. signifikant reduzierte CAV1-Mengen in HUVEC. Die Ergebnisse zeigen, dass epigenetische Veränderungen wertvolle Informationen zur Diagnostik, Prognostik und Progression des PCa liefern. Zudem konnte CAV1 als potentieller Marker des PCa identifiziert werden., The focus of the thesis was to evaluate molecular possibilities to find suitable biomarkers for prostate cancer (PCa). First, the epigenetic promoter methylation patterns of several genes (GSTP1, RARbeta2, APC and PITX2, respectively) were investigated for a possible methylation field effect. The RARbeta2 promoter methylation could be determined as a possible marker for tumor prediction in histologically normal-appearing tissue. GSTP1 showed a highly specific tumor methylation, underlining its diagnostic potential. The methylation also correlated with pathological parameters. Screening in an array format identified other genes whose promoter hypermethylation could be diagnostically interesting. Furthermore, gene expression analysis of angiogenic and endothelial-associated factors was performed to determine their diagnostic and prognostic potentials for PCa. For CAV1, a significant down-regulation of its mRNA level could be determined in the tumor. Bisulfite sequencing of seven CpG dinucleotides in the CAV1 promoter showed different methylation patterns between tumor and tumor adjacent tissue that could cause a reduced transcription. Furthermore, treatment of the CAV1-deficient LNCaP cell line with 5-aza-2-deoxycytidine led to CAV1 reexpression. Additionally, CAV1 inversely associated with pathological parameters and showed prognostic and diagnostic relevance. Immunohistochemical analysis clearly demonstrated decreases in CAV1 protein expression in endothelial cells and fibroblasts of the tumor. Conditioned media of cultivated tumor cells partly induced downregulation of the CAV1 protein level in HUVEC. The results show that epigenetic and angiogenic processes play crucial roles and provide valuable information for diagnosis, prognosis and progression of PCa. Moreover, CAV1 could be identified as a potential marker of prostate cancer.

Caveolae and caveolin-1 (CAV1) have been linked to several cellular functions. However, a model explaining their roles in mammalian tissues in vivo is lacking. Unbiased expression profiling in several tissues and cell types identified lipid metabolism as the main target affected by CAV1 deficiency. CAV1−/− mice exhibited impaired hepatic peroxisome proliferator-activated receptor α (PPARα)-dependent oxidative fatty acid metabolism and ketogenesis. Similar results were recapitulated in CAV1-deficient AML12 hepatocytes, suggesting at least a partial cell-autonomous role of hepatocyte CAV1 in metabolic adaptation to fasting. Finally, our experiments suggest that the hepatic phenotypes observed in CAV1−/− mice involve impaired PPARα ligand signaling and attenuated bile acid and FXRα signaling. These results demonstrate the significance of CAV1 in (1) hepatic lipid homeostasis and (2) nuclear hormone receptor (PPARα, FXRα, and SHP) and bile acid signaling.

Background: Caveolin-1 (Cav-1), the major component of caveolae, is a multifunctional scaffolding protein that serves as a platform for the cell’s signal-transduction and plays a role in inflammation. However, its role in inflammatory bowel disease (IBD), a chronic inflammatory condition in the gastrointestinal tract, is not clear. A recent study shows that Cav-1 mediates angiogenesis in dextran sodium sulphate (DSS)-induced colitis. These results contradict our data, in which Cav-1 levels decreased significantly in 2,4,6-trinitrobenzene sulphonic acid (TNBS)–induced colitis. Methods: To test whether Cav-1 is involved in IBD pathogenesis, various models representing different dominant Th subtype responses and mimicking the immune pathologic mechanisms of different clinical IBD setting were employed: acute colitis was induced by intra-rectal administration of a single dose of TNBS in BALB/c and C57BL/6J mice, or by drinking 3% DSS water for 6 days in C57BL/6J mice. Chronic colitis was induced by administration of TNBS once a week for 7 weeks in BALB/c mice. To assess the effects of complete loss of Cav-1, Cav-1 knock-out (Cav-1-/-) and control wild-type C57BL/6J mice received a single TNBS administration. To further test the possible role of Cav-1, one of two peptides (that either mimicked (Caveolin scaffolding domain; CSD) or antagonized (Caveolin-1 binding domain; CBD1) Cav-1)) was administered intraperitoneally to mice receiving TNBS. Body weight and clinical scores were monitored. Colon Cav-1 and pro-inflammatory cytokine levels were quantified by ELISA. Inflammation was evaluated through histological analysis. Results: Cav-1 levels in mouse colon tissue were significantly decreased in TNBS-induced colitis mice when compared to normal mice and also inversely correlated with colon inflammation and cytokine levels. Furthermore, a loss of Cav-1 (Cav-1-/-) showed increased clinical and inflammatory scores and increased body weight loss. Mice receiving peptides to alt

Inflammatory and metabolic disease, such as atherosclerosis and obesity, are the main causes of morbidity and mortality in western societies. In this thesis we show that loss of certain cell structures called caveolin-1, which are important in lipid transport, protects against the initiation and progression of atherosclerosis and that hematopoietic specific loss of caveolin-1 leads to an anti-inflammatory state. Furthermore, we establish an important function for the pro-inflammatory CD40L-CD40-TRAF signaling cascade in atherosclerosis as well as in obesity. We provide strong evidence that a precise intervention in Caveolin-1 biology and CD40L-CD40-TRAF signaling harbors the potential to develop new therapeutic agents to treat inflammatory disease.

Neisseria gonorrhoeae verursacht die sexuell übertragbare Krankheit Gonorrhoe und ist ein Typ-IV-Pili (Tfp) exprimierendes Bakterium, das den Urogenitaltrakt besiedelt. Frühe Infektionsstadien piliierter N. gonorrhoeae (P+GC) sind durch die Tfp-vermittelte Adhärenz an Wirtszellen gekennzeichnet, dann erfolgt die Bildung von Mikrokolonien auf Wirtszellepithelien. Hier wird gezeigt, dass die Wirtszellen an der effizienten Bildung der extrazellulären Mikrokolonien beteiligt sind. P+GC die fixierte Wirtszellen infizieren weisen eine verzögerte Mikrokoloniebildung gegenüber einer Infektion lebender Wirtszellen auf. Kortikales Aktin wird zusammen mit Signalproteinen innerhalb der Wirtszellen zu den adhärierten Bakterien rekrutiert, darunter das Hauptstrukturprotein von Caveolae-Membrandomänen, Caveolin-1 (Cav1). Eine Reduzierung der Expression von Cav1 führt zu einer verstärkten Aufnahme von P+GC in die Wirtszellen, wohingegen die Expression von Cav1 in Cav1-negativen Zellen eine Internalisierung verhindert. Internalisierte Bakterien weisen dabei geringere Überlebensraten auf je länger sie in den Wirtszellen verbleiben. Die Rekrutierung von Cav1 ist eine unmittelbare und kontinuierliche zelluläre Antwort auf eine Infektion mit P+GC, welche die Phosphorylierung von Cav1 an Tyrosin 14 bedingt. Zusätzlich erforderte die Cav1-vermittelte Blockierung der Internalisierung der Bakterien und die Verankerung von Cav1 mit dem Zytoskelett eine Tyrosinphosphorylierung von Cav1. Eine Analyse möglicher Interaktionspartner von phosphoryliertem Cav1 zeigte eine direkte Interaktion mit Vav2. Sowohl Vav2 als auch sein Substrat, die kleine GTPase RhoA, blockieren die Aufnahme von Bakterien in die in Wirtszellen. Die Aktivierung von RhoA nach P+GC Infektion erfordert die Expression von Cav1, was auf einen Cav1-Vav2-RhoA Signalweg hindeutet. Darüber hinaus wurden in dieser Arbeit sechs neue, eine SH2-Domäne-beinhaltende Interaktionspartner von phosphoryliertem Cav1 identifiziert., Neisseria gonorrhoeae causes the sexually transmitted disease gonorrhea and colonizes mucosal epithelia of the human urogenital tract. The early stages of infection with piliated N. gonorrhoeae (P+GC) are characterized by Tfp-mediated adherence to host cells, followed by formation of bacterial microcolonies on the surface of host cells. This study provides evidence that host cell participation is required for the efficient formation of extracellular microcolonies during Neisseria infection. P+GC infecting fixed host cells demonstrate altered motility and delayed microcolony formation compared to infecting living host cells. Cortical actin and various signal transducing proteins are recruited to the site of bacterial attachment within host cells, one of them being the major structural protein of plasma membrane caveolae, Caveolin-1 (Cav1). Down-regulation of Cav1 results in increased uptake of P+GC into host cells whereas expression of the protein in Cav1-negative cells blocks bacterial internalization. Host cell entry results in decreased viability of internalized bacteria over time. Cav1 recruitment is demonstrated to be an immediate and continuous cellular response to P+GC infection that involves Cav1 phosphorylation on its tyrosine 14 residue. Prevention of bacterial uptake mediated by Cav1 as well as tight association of Cav1 with the cytoskeleton also requires tyrosine phosphorylation. A broad analysis of interaction partners of phosphorylated Cav1 revealed a direct interaction with the Rho-family guanine nucleotide exchange factor Vav2. Both Vav2 and its substrate, the small GTPase RhoA, are involved in preventing bacterial uptake and RhoA activation after P+GC infection requires Cav1 expression, thus providing evidence for a Cav1-Vav2-RhoA signaling cascade. Moreover, six novel SH2-domain containing interaction partners of tyrosine phosphorylated Cav1 have been identified, all of which have been implicated in modulating the cytoskeleton.

Allergic asthma is a syndrome characterized by respiratory distress in response to environmental triggers. This atypical response to an allergen is an over reaction of the immune system causing an influx of inflammatory cells into the airway and concomitant airway smooth muscle constriction. Firstly, we demonstrate using whole house dust mite (HDM) extract as a sensitizing allergen produces an equivalent or more robust hyperresponsive and inflammatory reaction than can be achieved with the widely used ovalbumin (OVA) sensitization / challenge protocol. Secondly, we investigated the role of caveolin-1 in the pathophysiology of allergic asthma . Our data suggest an important role for cav-1 in down regulating allergic airway inflammation, leading to reduced airways hyperresponsiveness and mucus overproduction.

Caveolin-1 (Cav1)/caveolae biology is intimately linked to actin dynamics and adhesion receptors. Caveolar domains are organized in hierarchical levels of complexity from curved or flatten caveolae to large, higher-order caveolar rosettes. We report that stress fibers controlled by Abl kinases and mDia1 determine the level of caveolar domain organization, which conditions the subsequent inward trafficking of caveolar domains induced upon loss of cell adhesion from the extracellular matrix. Abl-deficient cells show decreased content of stress fibers, a smaller stress-fiber co-aligned Cav1 pool and increased clustering of Cav1/caveolae at the cell surface. Defective caveolar linkage to stress fibers prevents the formation of big caveolar rosettes upon loss of cell adhesion, correlating with a lack of inward trafficking. Live imaging of stress fibers and Cav1 showed that the actin-linked Cav1 pool loses its spatial organization in the absence of actin polymerization and is dragged and clustered by depolymerizing filaments. We identify mDia1 as the actin polymerization regulator downstream of Abl kinases that controls the stress fiber-linked Cav1 pool. mDia1 knockdown results in Cav1/caveolae clustering and defective inward trafficking upon loss of cell adhesion. In contrast, cell elongation imposed by the excess of stress fibers induced by active mDia1 flattens caveolae. Furthermore, active mDia1 rescues the actin co-aligned Cav1 pool and Cav1 inward trafficking upon loss of adhesion in Abl-deficient cells. Thus, caveolar domain organization and trafficking are tightly coupled to adhesive and stress fiber regulatory pathways

Activation of Stat3 has been demonstrated in breast and other cancers. However, the exact mechanisms of its activation as well as the role of Stat3 in these tumors, remain to be determined. This study focuses on the identification of the upstream activators of Stat3 in confluent cells as well as the role of Stat3 in this setting. To explore the nature of cell to cell adhesion molecules responsible for Stat3 activation in breast cancer, we examined the role of cadherin- 11 engagement using mouse Balb/c3T3 fibroblasts, which have high amounts of Cadherin -11. Cadherin-11 knockdown experiments demonstrated that this increase is required for Stat3 activation. Plating the cells on surfaces functionalised with cadherin-11 derived fragments caused a dramatic increase in Stat3-ptyr705 levels, indicating that cadherin-11 can directly activate Stat3, in the absence of cell to cell contact. Our results also demonstrated a reciprocal regulation between cav1 and Stat3. cav-1 downregulation through expression of shRNA activates Stat3, and conversely, cav1 overexpression downregulates Stat3 and induces growth retardation or apoptosis in mouse fibroblasts, as well as in breast cancer lines. In all cases, apoptosis was inhibited by co-expression of the constitutively active form of Stat3, Stat3C. Taken together, these findings point to cav1 as an inhibitor of Stat3 activity. In addition, it was previously demonstrated that cav1 upregulates p53, although the exact mechanism is unclear. Since Stat3 is known to inhibit p53 transcription through direct promotor binding, these data also point to the possibility that cav1 upregulation may, in fact, activate p53 through Stat3 inhibition. We also further demonstrate for the first time that, in a feedback loop, Stat3 inhibition results in a dramatic increase in cav1 levels, indicating that Stat3 also downregulates cav1 expression. Taken together, our findings reveal the presence of a potent, negative regulatory loop between cav1, p53 and

Vasoconstrictor responsiveness of the systemic circulation is attenuated following prolonged exposure to hypoxia. Previous work from our laboratory has demonstrated vasoconstrictor reactivity is diminished due to hyperpolarization of the vascular wall in systemic arterioles. The hyperpolarization of the vascular wall was found to be dependent upon the endothelium, heme oxygenase (HO), and calcium-activated large conductance potassium channel (BKCa) as removal of the endothelium or blockade of HO or BKCa restored vasoreactivity. Interestingly, recent evidence for HO and BKCa association has emerged in carotid body glomus cells where HO and BKCa form oxygen sensing complexes. In these novel oxygen sensing complexes, HO-derived CO activates BKCa channels in localized domains that regulate carotid body membrane potential. The presence and function of HO and BKCa association has not been previously acessed in the systemic endothelium. The following studies investigated a novel HO-BKCa functional unit in systemic vascular endothelial cells. In whole cell patch clamp experiments it was demonstrated that HO-dependent activation of BKCa significantly increased transmembrane currents in ECs following CH. Additionally, HO-dependent BKCa activity was unearthed following disruption of caveolin-1 function or potentially inhibited following incubation with the caveolin-1 scaffolding domain, demonstrating the inhibitory role of caveolin-1 on HO-BKCa complexes. Membrane potential recordings and isolated arteriole experiments further demonstrated EC BKCa regulates EC Em and vasoconstrictor reactivity following CH through a loss in caveolin-1 inhibition. This study is the first to characterize HO-dependent BKCa activation regulation by caveolin-1 and demonstrate a functional role for endothelial BKCa in vascular tone.

We have proposed that prostate cancer cells secrete cav-1 which induces specific changes in EC which potentiate angiogenesis and metastatic activities. We have reported that prostate cancer cell derived, secreted caveolin-1 is taken up by cancer cells and tumor associated endothelial cells (Tahir et al, Cancer Res 2008). This autocrine/paracrine activity of secreted caveolin-1 promotes malignant progression by stimulation of specific angiogenic activities. We have shown in cav-1 negative LP-LNCaP cells that adenoviral vector mediated expression of cav-1 stimulated VEGF mediated VEGFR2 autophosphorylation and activated downstream signaling, whereas cav-1 knockdown in PC-3 and HUVECs impaired the VEGF-stimulated angiogenesis signaling. This showed cav-1 is an important regulator of basal and VEGF-stimulated angiogenesis signaling in prostate cancer cells and HUVECs (Tahir et al, Cancer Biol Ther 2009). Furthermore, we sought to determine whether there was any potential correlation between cav-1 and the GFs such as VEGF, TGF-beta1, and FGF2. Our work revealed that cav-1 enhances cancer cell motility in an Akt-dependent manner and it up-regulates VEGF, TGF-beta1 and FGF2 through Aktmediated maintenance of mRNA stability (Li et al. Mol Cancer Res 2009). Using cav-1 knock out mice system, we have shown wet prostate tumor weight of RM-9 was significantly reduced in cav-1-/- mice compared with cav-1+/+ mice. Also, tumor wet weight was significantly reduced in cav-1 / mice which received cav-1 Ab compared to the mice treated with control IgG or HBSS only. Treatment with cav-1 Ab produced reduced lung metastasis in cav-1-/- model and increased survival time compared to the cav-1-/- littermate treated with control IgG or HBSS only( Watanabe et al. Mol cancer Res. 2009)., The original document contains color images.

Caveolin 1 (cav-1) is the basic component of the flask-shaped membrane microdomains known as caveolae that are involved in various cell functions. Caveolin 1 can be overexpressed in tumors,suggesting a proneoplastic role, or it can be downregulated. We previously reported that cav-1 expression increases with tumor grade in astrocytomas. Here, we studied cav-1 immunoreactivity in brain umors with an oligodendroglial component to determine the prognostic value of cav-1 expression and to correlate it with 1p/19q deletions. Fifty-four oligodendrogliomas, 26 mixed oligoastrocytomas,and 7 glioblastomas with an oligodendroglial component were assessed for cav-1 expression by immunohistochemistry and for 1p/19q status by fluorescence in situ hybridization. Caveolin-1 was detected in a minority of cases (22%) and was associated mostly with Grade III mixed oligoastrocytomas and glioblastomas with anoligodendroglial component; cav-1 expression was significantly correlated with the absence of a 1p/19q deletion (p = 0.0002). In the 63 cases in which survival data were available, cav-1 expression was also significantly associated with shorter survivals, whereas 1p/19q deletion was associated with longer survivals. Among high-grade tumors, cav-1 expression was the only factor that retained a statistical significance after multivariate analysis for the prediction ofa short survival (p G 0.015). These data are the first evidence that cav-1 immunohistochemistry is an independent prognostic marker in tumors with an oligodendroglial component regardless of the 1p/19q status., Journal Article, Research Support, Non-U.S. Gov't, info:eu-repo/semantics/published

In adipocytes, PDE3B (phosphodiesterase 3B) is an important regulatory effector in signalling pathways controlled by insulin and cAMP-increasing hormones. Stimulation of 3T3-L1 adipocytes with insulin or the beta(3)-adrenergic receptor agonist CL316243 (termed CL) indicated that insulin preferentially phosphorylated/activated PDE3B associated with internal membranes (endoplasmic reticulum/Golgi), whereas CL preferentially phosphorylated/activated PDE3B associated with caveolae. siRNA (small interfering RNA)-mediated KD (knockdown) of CAV-1 (caveolin-1) in 3T3-L1 adipocytes resulted in down-regulation of expression of membrane-associated PDE3B. Insulin-induced activation of PDE3B was reduced, whereas CL-mediated activation was almost totally abolished. Similar results were obtained in adipocytes from Cav-1-deficient mice. siRNA-mediated KID of CAV-1 in 3T3-L1 adipocytes also resulted in inhibition of CL-stimulated phosphorylation of HSL (hormone-sensitive lipase) and perilipin A, and of lipolysis. Superose 6 gel-filtration chromatography of solubilized membrane proteins from adipocytes stimulated with insulin or CL demonstrated the reversible assembly of distinct macromolecular complexes that contained P-32-phosphorylated PDE3B and signalling molecules thought to be involved in its activation. Insulin- and CL-induced macromolecular complexes were enriched in cholesterol, and contained certain common signalling proteins [14-3-3, PP2A (protein phosphatase 2A) and cav-1]. The complexes present in insulin-stimulated cells contained tyrosine-phosphorylated IRS-1 (insulin receptor substrate 1) and its downstream signalling proteins, whereas CL-activated complexes contained beta(3)-adrenergic receptor, PKA-RII [PKA (cAMP-dependent protein kinase)-regulatory subunit] and HSL. Insulin- and CL-mediated macromolecular complex formation was significantly inhibited by CAV-1 KID. These results suggest that cav-1 acts as a molecular chaperone or scaffolding molecule in cholesterol

We have made a significant progress toward our stated goals. Notable achievements for the past year of funding include comprehensive documentation that prostate cancer cell derived, secreted caveolin-1 is taken up by cancer cells and tumor associated endothelial cells (Tahir et al, Cancer Res 2008). This autocrine/paracrine activity of secreted caveolin-1 promotes malignant progression by stimulation of specific angiogenic activities. We have shown in cav-1 negative LP-LNCaP cells that adenoviral vector mediated expression of cav-1 stimulated VEGF mediated VEGFR2 autophosphorylation and activated downstream signaling. We are further exploring cav-1 mediated angiogenic signaling in endothelial cell models, including the possibility of direct interactions between cav-1 and VEGFR2. Our animal model studies have shown that systemic delivery of cav-1 antiserum suppresses primary tumor growth and lung metastasis in a pre-established metastasis prostate cancer model. Moreover, systemic treatment with cav-1 Ab increased survival in the mouse model of prostate cancer (see Fig 6-8). Our results indicate that cav-1 may be a clinically useful biomarker of prostate cancer progression and a potential therapeutic target., The original document contains color images.

AIMS: In endothelial cells, caveolin-1 (cav-1) is known to negatively modulate the activation of endothelial nitric oxide synthase, a key regulator of blood pressure (BP). However, the impact of genetic alteration of cav-1 on vascular nitric oxide (NO) production and BP homeostasis in vivo is unknown. METHODS AND RESULTS: We used spectral analysis of systolic blood pressure (SBP) variability in mice chronically equipped with telemetry implants to identify frequency ranges (0.05-0.4 Hz; very low frequency, VLF) specifically responding to NO, independently of changes in absolute BP or systemic neurohormone levels. VLF variability was inversely correlated to aortic vasodilator-stimulated Ser(239) phosphoprotein (VASP) phosphorylation, reflecting NO bioactivity. We show that mice deficient in cav-1 have decreased VLF variability paralleled with enhanced systemic and vascular production of NO at unchanged mean SBP levels. Conversely, VLF variability was increased upon acute injection of mice, with a peptide containing the caveolin-scaffolding domain (CSD; residues 82-101) fused to an internalization sequence of antennapedia that decreased vascular and circulating NO in vivo. CONCLUSION: These data highlight the functional importance of cav-1 for the production of bioactive NO in conduit arteries and its control of central BP variability. Given the impact of the latter on target organ damage, this raises the interest for genetic, pharmacological, or molecular interventions that modulate cav-1 expression in diseases with NO-dependent endothelial dysfunction.

Although several mechanisms have been proposed to explain the putative role of beta-carotene in cancer, no studies have investigated a possible influence of beta-carotene on caveolin-1 (cav-1) pathway, an important intracellular signaling deregulated in cancer. Here, different human colon and prostate cancer cell lines, expressing (HCT-116, PC-3 cells) or not (Caco-2, LNCaP cells) cav-1, were treated with varying concentrations of beta-carotene (0.5-30 muM) for different periods of time (3-72 h) and the effects on cell growth were investigated. The results of this study show that (i) beta-carotene acted as a growth-inhibitory agent in cav-1-positive cells, but not in cav-1-negative cells; (ii) in cav-1-positive cells, the carotenoid downregulated in a dose- and time-dependent manner the expression of cav-1 protein and messenger RNA levels and inhibited AKT phosphorylation which, in turn, stimulated apoptosis by increasing the expression of beta-catenin and c-myc and the activity of caspases-3, -7, -8 and -9; when the carotenoid was removed from culture medium, a progressive increase in cell growth was observed with respect to beta-carotene-treated cells and (iii) the transfection of cav-1 in cav-1-negative cells increased cell sensitivity to beta-carotene by inducing apoptosis. This effect was accompanied by a reduction of both cav-1 and AKT phosphorylation and by an increase of c-myc and beta-catenin expression. Silencing of c-Myc attenuated beta-carotene-induced apoptosis and beta-catenin expression. All together, these data suggest that the modulation of cav-1 pathway by beta-carotene could be a novel mechanism by which the carotenoid acts as a potent growth-inhibitory agent in cancer cells

The small GTP-ase Rac-1 can trigger p38 MAPK activation and, in turn, p38alpha can regulate signalling pathways that potentially impinge on Rac-1 activity. We have investigated the cross-talk between p38alpha and Rac-1 and found that p38alpha regulates the association between Rac-1 and caveolin-1 in serum-deprived cardiomyocytes. This interaction depends on cell attachment and correlates with higher levels of active Rac-1. Actin organization might regulate the formation of Rac-1-caveolin-1 complexes. In contrast, the Rac-1-caveolin-1 interaction is almost undetectable in the presence of serum, where Rac-1 activity is negatively regulated by p38alpha. Our results indicate that p38alpha can differentially contribute to Rac-1 activation depending on the presence of serum., Ministerio de Sanidad (España), Ministerio de Educación y Ciencia (España), Comunidad de Madrid, Depto. de Bioquímica y Biología Molecular, Fac. de Farmacia, TRUE, pub

My laboratory relocated to M. D. Anderson Cancer Center on October 1, 2008. The move and transition was handled in a very efficient manner and we did not compromise our progress toward the goals of this project in any way. With only slight modifications Tasks 1-3 are on schedule and we are progressing toward our stated goals. Notable achievements for the past year of funding include comprehensive documentation that prostate cancer cell derived, secreted caveolin-1 is taken up by cancer cells and tumor associated endothelial cells (Tahir et al., Cancer Res 68: 731-739, 2008). This autocrine/paracrine activity of secreted caveolin-1 promotes malignant progression and provides an accessible therapeutic target. In pursuit of a clinical therapy based on this mechanism we have also shown that systemic delivery of caveolin-1 antiserum suppresses primary tumor growth and increases survival in an immunocompetent mouse model of prostate cancer (see Fig 5-7). In our view these results represent a paradigm shift in prostate cancer translational research., The original document contains color images.

Caveolae, plasma membrane invaginations particularly abundant in adipocytes, have been suggested to be important in organizing insulin signalling. Insulin-induced activation of the membrane bound cAMP degrading enzyme, phosphodiesterase 3B (PDE3B) is a key step in insulin-mediated inhibition of lipolysis and is also involved in the regulation of insulin-mediated glucose uptake and lipogenesis in adipocytes. The aim of this work was to evaluate whether PDE3B is associated with caveolae. Subcellular fractionation of primary rat and mouse adipocytes demonstrated the presence of PDE3B in endoplasmic reticulum and plasma membrane fractions. The plasma membrane PDE3B was further analyzed by detergent treatment at 4 degrees C, which did not solubilize PDE3B, indicating an association of PDE3B with lipid rafts. Detergent-treated plasma membranes were studied using Superose-6 chromatography which demonstrated co-elution of PDE3B with caveolae and lipid raft markers (caveolin-1, flotillin-1 and cholesterol) at a Mw of > 4000 kDa. On sucrose density gradient centrifugation of sonicated plasma membranes, a method known to enrich caveolae, PDE3B co-migrated with the caveolae markers. Immunoprecipitation of caveolin-1 using anti caveolin-1 antibodies co-immunoprecipitated PDE3B and immunoprecipitation of flag-PDE3B from adipocytes infected with a flag-PDE3B adenovirus resulted in co-immunoprecipitation of caveolin-1. Studies on adipocytes with disrupted caveolae, using either caveolin-1 deficient mice or treatment of adipocytes with methyl-beta-cyclodextrin, reduced the membrane associated PDE3B activity. Furthermore, inhibition of PDE3 in primary rat adipocytes resulted in reduced insulin stimulated glucose transporter-4 translocation to caveolae, isolated by immunoprecipitation using caveolin-1 antibodies. Thus, PDE3B, a key enzyme in insulin signalling, appears to be associated with caveolae in adipocytes and this localization seems to be functionally important. (c) 2006 Elsev

In blood vessels, endothelia are submitted to constant shear effects and are, under normal conditions, capable of responding to any variation in hemodynamic forces. Caveolae — 50- to 100-nm plasma membrane invaginations present at the surface of terminally differentiated cells and particularly enriched in ECs — are composed of a high sphingolipid and cholesterol content and the protein caveolin-1 (Cav-1). Previous studies have suggested that caveolae and endothelial Cav-1 may regulate the vascular response to altered shear stress. In this issue of the JCI, Yu et al. have examined the role of Cav-1/caveolae in the regulation of flow-induced alterations (i.e., mechanotransduction) in vessels from wild-type mice, Cav-1–deficient mice, and Cav-1–deficient mice re-expressing Cav-1 only in ECs. Their data suggest that caveolae/Cav-1 may act as sensors of altered shear stress and that they also organize the signaling response in stimulated ECs.

In the past three years, we identified and preliminarily characterized a novel serine/threonine p21 activated protein kinase 6 (PAK 6) as the key signal mediator in regulating AR signal transduction within caveolae/raft domain. We also demonstrated a cross-talk between the caveolin-1/AR and PI3 kinase/Akt signal pathway in hormone dependent cell survival. Overall, our results established a biochemical basis on the notion that caveolin expression is associated with prostate cancer progression. The "neoexpression" caveolin in prostate cancer progression represents a gain of function event in cancer survival. These results illustrate the important role of AR non-genomic effect in response to androgen stimulation. Moreover, the identification of a novel serine/threonine PAK6 kinase underscores the relevance of this signal pathway in mediating AR nongenomic effects. Our results support the hypothesis from our original proposal that AR signals from rafts to regulate its transcriptional function. These findings pave the way to further define the underlying signal cross-talk in AR-mediated signaling.

Caveolins, the proteins which were found in "little caves" named caveolae more than 50 years ago, have been revealed to work to maintain the form and functions of many kinds of cells. Therefore malfunction of caveolins is related to diseases such as tumors, atherosclerosis, muscular dystrophy, pulmonary disfunction and other diseases. The introduction of caveolin-deficient mice brought new methods to approach the mechanisms of both normal cell function and the onset of these diseases. Although we examined caveolin distribution in human tissue, it has been difficult to establish a relationship between the caveolins and hormone secretion. However, as caveolin-1 has direct functional interactions with insulin receptors, Type II diabetes mellitus has become one subject for caveolin research. In terms of tumorigenesis, there are some reports of overexpression of caveolin-1 and -2 in tumors of the thyroid and parathyroid. Caveolins are proteins which have the potential for much further research, from many points of view., 4, KJ00004437028, P, Review

The apolipoprotein E receptor 2 (apoER2) is a member of the low-density lipoprotein receptor family which binds ligands such as reelin, apolipoprotein E and apolipoprotein J/clusterin and has been shown to play roles in neuronal migration during development and in male fertility. The function of apoER2 mainly depends on cellular signaling triggered by ligand binding. Although the receptor is internalized, the mechanism and functional significance of its endocytic trafficking remain unclear. Apolipoprotein E receptor 2 partitions into lipid rafts and interacts with caveolin-1, a feature that could modulate its endocytic behavior. Recent evidence also suggested that apoER2 might be endocytosed by a pathway independent of clathrin. Here, we show that despite a raft association, apoER2 internalization depends on its cytoplasmic FxNPXY motif that is similar to canonical motifs for clathrin-mediated endocytosis. This motif mediates receptor binding to the adaptor protein Dab2, which can interact directly with clathrin. Several inhibitory conditions of clathrin-mediated endocytosis, including expression of the dominant negative forms of eps15 and Dab2, decreased apoER2 internalization. In contrast, treatment with the drug nystatin, which blocks the caveolar/raft internalization pathway, has no effect on the receptor's endocytosis. Neither the transmembrane nor the proline-rich insert of the cytoplasmic domain, which has been previously reported to exclude the receptor from the clathrin-mediated pathway, altered apoER2 endocytic activity. These studies indicate that apoER2 internalizes through a clathrin-mediated pathway and that its association with caveolar and noncaveolar rafts does not determine its endocytosis. Copyright © Blackwell Munksgaard 2005.