ABSTRACT
Cytochrome P450 2E1 (CYP2E1) is a key target protein in the development of alcoholic and nonalcoholic fatty liver disease (FLD). The pathophysiological correlate is the massive production of reactive oxygen species. The role of CYP2E1 in the development of hepatocellular carcinoma (HCC), the final complication of FLD, remains controversial. Specifically, CYP2E1 has not yet been defined as a molecular target for HCC therapy. In addition, a CYP2E1-specific drug has not been developed. We have already shown that our newly developed CYP2E1 inhibitor 12-imidazolyl-1-dodecanol (I-ol) was therapeutically effective against alcoholic and nonalcoholic steatohepatitis. In this study, we investigated the effect of I-ol on HCC tumorigenesis and whether I-ol could serve as a possible treatment option for terminal-stage FLD. I-ol exerted a very highly significant antitumour effect against hepatocellular HepG2 cells. Cell viability was reduced in a dose-dependent manner, with only the highest doses causing a cytotoxic effect associated with caspase 3/7 activation. Comparable results were obtained for the model colorectal adenocarcinoma cell line, DLD-1, whose tumorigenesis is also associated with CYP2E1. Transcriptome analyses showed a clear effect of I-ol on apoptosis and cell-cycle regulation, with the increased expression of p27Kip1 being particularly noticeable. These observations were confirmed at the protein level for HepG2 and DLD-1 cells grafted on a chorioallantoic membrane. Cell-cycle analysis showed a complete loss of proliferating cells with a simultaneous increase in S-phase arrest beginning at a threshold dose of 30 µM. I-ol also reduced xenograft tumour growth in nude mice. This antitumour effect was not associated with tumour cachexia. I-ol was not toxic to healthy tissues or organs. This study demonstrates for the first time the therapeutic effect of the specific CYP2E1 inhibitor I-ol on the tumorigenesis of HCC. Our findings imply that I-ol can potentially be applied therapeutically on patients at the final stage of FLD.
Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Animals , Carcinoma, Hepatocellular/drug therapy , Cytochrome P-450 CYP2E1/metabolism , Dodecanol , Humans , Liver Neoplasms/drug therapy , Mice , Mice, Nude , Oxidative StressABSTRACT
Heterogeneous nuclear ribonucleoprotein K (hnRNP K) is overexpressed in malignant tumors and involved in DNA damage response upon ionizing radiation (IR). Here, we investigate its role in radioresistance of colorectal carcinoma (CRC) and evaluate a pharmacological approach to enhance CRC radiosensitivity via downregulation of hnRNP K. We show that hnRNP K is overexpressed in CRC tissue specimens and upregulated in response to IR in vitro, which occurs faster in KRAS-mutant CRC cells. HnRNP K knockdown impairs cell survival, cell cycle progression and KRAS-dependent radioresistance and increases apoptosis. Using the chicken chorioallantoic membrane assay, a decrease in xenograft tumor growth and radioresistance upon hnRNP K depletion could be verified in vivo, and comparable effects were achieved by suppression of hnRNP K expression using the MEK inhibitor MEK162 (Binimetinib). In summary, KRAS-mutant CRC shows intrinsic radioresistance along with rapid upregulation of hnRNP K in response to IR that can effectively be targeted by MEK inhibition. Our results point towards a possible use of MAPK pathway inhibitors to decrease radioresistance of KRAS-mutant CRC via downregulation of hnRNP K.
Subject(s)
Biomarkers, Tumor/genetics , Colorectal Neoplasms/radiotherapy , MAP Kinase Kinase Kinases/metabolism , Mutation , Proto-Oncogene Proteins p21(ras)/genetics , Radiation Tolerance/genetics , Ribonucleoproteins/metabolism , Signal Transduction/radiation effects , Aged , Aged, 80 and over , Animals , Apoptosis/radiation effects , Cell Cycle/radiation effects , Cell Line, Tumor , Chick Embryo , Chorioallantoic Membrane/blood supply , Colorectal Neoplasms/enzymology , Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Dose-Response Relationship, Radiation , Female , Gene Expression Regulation, Neoplastic , Genetic Predisposition to Disease , Heterogeneous-Nuclear Ribonucleoprotein K , Humans , MAP Kinase Kinase Kinases/antagonists & inhibitors , Male , Middle Aged , Phenotype , Protein Kinase Inhibitors/pharmacology , RNA Interference , Radiation Tolerance/drug effects , Ribonucleoproteins/genetics , Signal Transduction/drug effects , Time Factors , Transfection , Up-RegulationABSTRACT
Cell fate decisions and pluripotency, but also malignancy depend on networks of key transcriptional regulators. The T-box transcription factor TBX3 has been implicated in the regulation of embryonic stem cell self-renewal and cardiogenesis. We have recently discovered that forced TBX3 expression in embryonic stem cells promotes mesendoderm specification directly by activating key lineage specification factors and indirectly by enhancing paracrine NODAL signalling. Interestingly, aberrant TBX3 expression is associated with breast cancer and melanoma formation. In other cancers, loss of TBX3 expression is associated with a more aggressive phenotype e.g. in gastric and cervical cancer. The precise function of TBX3 in pancreatic ductal adenocarcinoma remains to be determined. In the current study we provide conclusive evidence for TBX3 overexpression in pancreatic cancer samples as compared to healthy tissue. While proliferation remains unaltered, forced TBX3 expression strongly increases migration and invasion, but also angiogenesis in vitro and in vivo. Finally, we describe the TBX3-dependency of cancer stem cells that perpetuate themselves through an autocrine TBX3-ACTIVIN/NODAL signalling loop to sustain stemness. Thus, TBX3 is a new key player among pluripotency-related genes driving cancer formation.
Subject(s)
Activins/metabolism , Neoplastic Stem Cells/cytology , Nodal Protein/metabolism , Pancreatic Neoplasms/pathology , T-Box Domain Proteins/metabolism , AC133 Antigen/metabolism , Adult , Aged , Aged, 80 and over , Apoptosis , Cell Movement , Cell Proliferation , Female , Humans , Male , Microscopy, Fluorescence , Middle Aged , Neoplastic Stem Cells/metabolism , Neovascularization, Pathologic , Pancreatic Neoplasms/metabolism , Phenotype , Spheroids, Cellular/cytology , Spheroids, Cellular/metabolism , T-Box Domain Proteins/geneticsABSTRACT
BACKGROUND: Initially identified as a molecule that regulates the final step of glycolysis, the M2 isoform of pyruvate kinase (PKM2) was recently reported to have a central role in the metabolic reprogramming of cancer cells as well as participating in cell cycle progression and gene transcription. Despite intensive efforts, the intricate molecular mechanisms through which PKM2 regulates tumor progression remain elusive. METHODS: The proliferation and apoptosis of various pancreatic cancer cells using lentiviral-mediated PKM2 abrogation were assessed in vitro via Western blot and flow cytometric assay while the in vivo experiments involved tumor xenograft on chicken chorionallantoic membranes and immunohistochemistry on human tissue specimens. In order to decipher the molecular mechanism of HIF-1α and p65/RelA regulation by PKM2 in cancer cells cultivated in hypoxic atmosphere or normoxia we involved various biochemical assays such as Western blotting, immunoprecipitation, reporter gene assay and ELISA. RESULTS: Strong expression of PKM2 was observed in 68 % of human pancreatic adenocarcinoma specimens and almost all analyzed pancreatic cancer cell lines. Abrogation of PKM2 resulted in impaired proliferation and augmented apoptosis in vitro as well as impaired tumor growth and decreased blood vessel formation in vivo. Furthermore, deletion of PKM2 negatively impacted hypoxia-induced HIF-1α accumulation and promoter activity ultimately resulting in impaired secretion of VEGF. CONCLUSIONS: Our study suggests that in hypoxic pancreatic tumors PKM2 interferes both with NF-κB/p65 and HIF-1α activation that ultimately triggers VEGF-A secretion and subsequent blood vessel formation.
Subject(s)
Carrier Proteins/metabolism , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Membrane Proteins/metabolism , NF-kappa B/metabolism , Neovascularization, Pathologic/pathology , Pancreatic Neoplasms/blood supply , Pancreatic Neoplasms/metabolism , Thyroid Hormones/metabolism , Adult , Aged , Aged, 80 and over , Animals , Apoptosis , Cell Hypoxia , Cell Line, Tumor , Cell Nucleus/metabolism , Cell Proliferation , Cell Survival , Chickens , Female , Gene Knockdown Techniques , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Male , Middle Aged , Models, Biological , Neovascularization, Pathologic/genetics , Pancreatic Neoplasms/genetics , Protein Binding , Protein Transport , Signal Transduction/genetics , Transcription Factor RelA/metabolism , Transcription, Genetic , Vascular Endothelial Growth Factor A/metabolism , Thyroid Hormone-Binding ProteinsABSTRACT
Metastasis is the survival-determining factor in urothelial carcinoma (UC) of the urinary bladder. The small conductance calcium-activated potassium channel 3 (SK3) enhances tumor cell invasion in breast cancer and malignant melanoma. Since Edelfosine, a glycerophospholipid with antitumoral properties, effectively inhibits SK3 channel activity, our goal was to evaluate SK3 as a potential molecular target to inhibit the gain of an invasive phenotype in UC. SK3 protein expression was analyzed in 208 tissue samples and UC cell lines. Effects of Edelfosine on SK3 expression and intracellular calcium levels as well as on cell morphology, cell survival and proliferation were assessed using immunoblotting, potentiometric fluorescence microscopy, and clonogenic/cell survival assay; furthermore, we analyzed the effect of Edelfosine and SK3 RNAi knockdown on tumor cell migration and invasion in vitro and in vivo. We found that SK3 is strongly expressed in muscle-invasive UC and in the RT112 cellular tumor model. Higher concentrations of Edelfosine have a strong antitumoral effect on UC cells, while 1 µM effectively inhibits migration/invasion of UC cells in vitro and in vivo comparable to the SK3 knockdown phenotype. Taken together, our results show strong expression of SK3 in muscle-invasive UC, consistent with the postulated role of the protein in tumor cell invasion. Edelfosine is able to effectively inhibit migration and invasion of UC cells in vitro and in vivo in an SK3-dependent way, pointing towards a possible role for Edelfosine as an antiinvasive drug to effectively inhibit UC cell invasion and metastasis.
Subject(s)
Carcinoma/drug therapy , Phospholipid Ethers/administration & dosage , Small-Conductance Calcium-Activated Potassium Channels/biosynthesis , Urinary Bladder Neoplasms/drug therapy , Adult , Aged , Calcium/metabolism , Carcinoma/genetics , Carcinoma/pathology , Cell Movement/drug effects , Female , Gene Expression Regulation, Neoplastic/drug effects , Humans , Male , Middle Aged , Neoplasm Invasiveness/genetics , Small-Conductance Calcium-Activated Potassium Channels/genetics , Urinary Bladder Neoplasms/genetics , Urinary Bladder Neoplasms/pathology , Urothelium/drug effects , Urothelium/pathologyABSTRACT
The protein kinase D isoenzymes PKD1/2/3 are prominent downstream targets of PKCs (Protein Kinase Cs) and phospholipase D in various biological systems. Recently, we identified PKD isoforms as novel mediators of tumour cell-endothelial cell communication, tumour cell motility and metastasis. Although PKD isoforms have been implicated in physiological/tumour angiogenesis, a role of PKDs during embryonic development, vasculogenesis and angiogenesis still remains elusive. We investigated the role of PKDs in germ layer segregation and subsequent vasculogenesis and angiogenesis using mouse embryonic stem cells (ESCs). We show that mouse ESCs predominantly express PKD2 followed by PKD3 while PKD1 displays negligible levels. Furthermore, we demonstrate that PKD2 is specifically phosphorylated/activated at the time of germ layer segregation. Time-restricted PKD2-activation limits mesendoderm formation and subsequent cardiovasculogenesis during early differentiation while leading to branching angiogenesis during late differentiation. In line, PKD2 loss-of-function analyses showed induction of mesendodermal differentiation in expense of the neuroectodermal germ layer. Our in vivo findings demonstrate that embryoid bodies transplanted on chicken chorioallantoic membrane induced an angiogenic response indicating that timed overexpression of PKD2 from day 4 onwards leads to augmented angiogenesis in differentiating ESCs. Taken together, our results describe novel and time-dependent facets of PKD2 during early cell fate determination.
Subject(s)
Mouse Embryonic Stem Cells/metabolism , Protein Kinases/metabolism , Animals , Cell Differentiation/drug effects , Cell Line , Chickens , Chorioallantoic Membrane/blood supply , Doxycycline/pharmacology , Embryoid Bodies/cytology , Embryoid Bodies/transplantation , Gene Knock-In Techniques , Immunohistochemistry , Induced Pluripotent Stem Cells/cytology , Induced Pluripotent Stem Cells/metabolism , Mice , Mice, Inbred C57BL , Mouse Embryonic Stem Cells/cytology , Neovascularization, Pathologic , Protein Kinase C/genetics , Protein Kinase C/metabolism , Protein Kinase D2 , Protein Kinases/genetics , Real-Time Polymerase Chain ReactionABSTRACT
The chick chorioallantoic membrane (CAM) model has been successfully used to study angiogenesis, cancer progression and its pharmacological treatment, tumor pharmacokinetics, and properties of novel nanomaterials. MRI is an attractive technique for non-invasive and longitudinal monitoring of physiological processes and tumor growth. This study proposes an age-adapted cooling regime for immobilization of the chick embryo, enabling high-resolution MRI of the embryo and the CAM tumor xenograft. 64 chick embryos were enrolled in this study. The novel immobilization and imaging protocol was optimized in 29 embryos. From d7 to d18 immobilization of the embryo up to 90 min was achieved by cooling at 4 °C pre-imaging, with cooling times adapted to age. Its application to tumor growth monitoring was evaluated in 15 embryos after xenotransplantation of human MDA-MB-231 breast cancer cells on CAM. Tumor volumes were monitored from d4 to d9 after grafting (d11 to d16 after incubation) applying a T2 -weighted multislice RARE sequence. At d9 after grafting, the tumors were collected and compared with the MRI-derived data by histology and weight measurements. Additional imaging methods comprising DWI, T2 mapping, and the bio-distribution of contrast agents were tested at d9 after grafting in 20 further embryos. With the adaptive cooling regime, motion artifacts could be completely avoided for up to 90 min scan time, enabling high-resolution in ovo imaging. Excellent anatomical details could be obtained in the embryo and tumors. Tumor volumes could be quantified over time. The results prove the feasibility of high-resolution MRI for longitudinal tumor and organ growth monitoring. The suggested method is promising for future applications such as testing tailored and/or targeted treatment strategies, longitudinal monitoring of tumor development, analysis of therapeutic efficacies of drugs, or assessment of tumor pharmacokinetics. The method provides an alternative to animal experimentation.
Subject(s)
Breast Neoplasms/pathology , Magnetic Resonance Imaging/methods , Animals , Cell Line, Tumor , Chick Embryo , Chorioallantoic Membrane , Contrast Media , Diffusion Magnetic Resonance Imaging/methods , Egg White , Egg Yolk , Feasibility Studies , Female , Gadolinium , Heterografts , Humans , Image Processing, Computer-Assisted/methods , Organometallic Compounds , Reproducibility of Results , Temperature , Tumor BurdenABSTRACT
The kinase PRKD2 (protein kinase D) is a crucial regulator of tumor cell-endothelial cell communication in gastrointestinal tumors and glioblastomas, but its mechanistic contributions to malignant development are not understood. Here, we report that the oncogenic chaperone HSP90 binds to and stabilizes PRKD2 in human cancer cells. Pharmacologic inhibition of HSP90 with structurally divergent small molecules currently in clinical development triggered proteasome-dependent degradation of PRKD2, augmenting apoptosis in human cancer cells of various tissue origins. Conversely, ectopic expression of PRKD2 protected cancer cells from the apoptotic effects of HSP90 abrogation, restoring blood vessel formation in two preclinical models of solid tumors. Mechanistic studies revealed that PRKD2 is essential for hypoxia-induced accumulation of hypoxia-inducible factor-1α (HIF1α) and activation of NF-κB in tumor cells. Notably, ectopic expression of PRKD2 was able to partially restore HIF1α and secreted VEGF-A levels in hypoxic cancer cells treated with HSP90 inhibitors. Taken together, our findings indicate that signals from hypoxia and HSP90 pathways are interconnected and funneled by PRKD2 into the NF-κB/VEGF-A signaling axis to promote tumor angiogenesis and tumor growth.
Subject(s)
HSP90 Heat-Shock Proteins/metabolism , Neovascularization, Pathologic/metabolism , Protein Kinase C/metabolism , Animals , Apoptosis/physiology , Cell Hypoxia/physiology , Cell Line, Tumor , Female , HCT116 Cells , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Mice , Mice, Nude , NF-kappa B/metabolism , Proteasome Endopeptidase Complex/metabolism , Signal Transduction/physiology , Vascular Endothelial Growth Factor A/metabolismABSTRACT
BACKGROUND: Advanced castration resistant prostate cancer (CRPC) is often characterized by an increase of C-terminally truncated, constitutively active androgen receptor (AR) variants. Due to the absence of a ligand binding domain located in the AR-C-terminus, these receptor variants (also termed ARΔLBD) are unable to respond to all classical forms of endocrine treatments like surgical/chemical castration and/or application of anti-androgens. METHODOLOGY: In this study we tested the effects of the naturally occurring stilbene resveratrol (RSV) and (E)-4-(2, 6-Difluorostyryl)-N, N-dimethylaniline, a fluorinated dialkylaminostilbene (FIDAS) on AR- and ARΔLBD in prostate cancer cells. The ability of the compounds to modulate transcriptional activity of AR and the ARΔLBD-variant Q640X was shown by reporter gene assays. Expression of endogenous AR and ARΔLBD mRNA and protein levels were determined by qRT-PCR and Western Blot. Nuclear translocation of AR-molecules was analyzed by fluorescence microscopy. AR and ARΔLBD/Q640X homo-/heterodimer formation was assessed by mammalian two hybrid assays. Biological activity of both compounds in vivo was demonstrated using a chick chorioallantoic membrane xenograft assay. RESULTS: The stilbenes RSV and FIDAS were able to significantly diminish AR and Q640X-signalling. Successful inhibition of the Q640X suggests that RSV and FIDAS are not interfering with the AR-ligand binding domain like all currently available anti-hormonal drugs. Repression of AR and Q640X-signalling by RSV and FIDAS in prostate cancer cells was caused by an inhibition of the AR and/or Q640X-dimerization. Although systemic bioavailability of both stilbenes is very low, both compounds were also able to downregulate tumor growth and AR-signalling in vivo. CONCLUSION: RSV and FIDAS are able to inhibit the dimerization of AR and ARΔLBD molecules suggesting that stilbenes might serve as lead compounds for a novel generation of AR-inhibitors.
Subject(s)
Prostatic Neoplasms/metabolism , Receptors, Androgen/drug effects , Stilbenes/pharmacology , Cell Line, Tumor , Dimerization , Humans , Male , Prostatic Neoplasms/pathology , Receptors, Androgen/chemistry , Receptors, Androgen/metabolism , Signal TransductionABSTRACT
AIM: In this article, we use an alternative cancer model for the evaluation of nanotherapy, and assess the impact of surface functionalization and active targeting of mesoporous silica nanoparticles (MSNPs) on therapeutic efficacy in vivo. MATERIALS & METHODS: We used the chorioallantoic membrane xenograft assay to investigate the biodistribution and therapeutic efficacy of folate versus polyethyleneimine-functionalized γ-secretase inhibitor-loaded MSNPs in breast and prostate tumor models. RESULTS: γ-secretase inhibitor-loaded MSNPs inhibited tumor growth in breast and prostate cancer xenografts. Folate conjugation improved the therapeutic outcome in folic acid receptor-positive breast cancer, but not in prostate cancer lacking the receptor. CONCLUSION: The results demonstrate that therapeutic efficacy is linked to cellular uptake of MSNPs as opposed to tumor accumulation, and show that MSNP-based delivery of γ-secretase inhibitors is therapeutically effective in both breast and prostate cancer. In this article, we present a model system for a medium-to-high throughput, cost-effective, quantitative evaluation of nanoparticulate drug carriers.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Breast Neoplasms/drug therapy , Drug Carriers/chemistry , Enzyme Inhibitors/therapeutic use , Nanoparticles/chemistry , Silicon Dioxide/chemistry , Triazines/therapeutic use , Animals , Enzyme Inhibitors/chemistry , Female , Humans , Mice , Mice, Nude , Porosity , Triazines/chemistryABSTRACT
OBJECTIVE: Oxidative stress is believed to play a key role in cardiovascular disorders. Thioredoxin (Trx) is an oxidative stress-limiting protein with anti-inflammatory and antiapoptotic properties. Here, we analyzed whether Trx-1 might exert atheroprotective effects by promoting macrophage differentiation into the M2 anti-inflammatory phenotype. METHODS AND RESULTS: Trx-1 at 1 µg/mL induced downregulation of p16(INK4a) and significantly promoted the polarization of anti-inflammatory M2 macrophages in macrophages exposed to interleukin (IL)-4 at 15 ng/mL or IL-4/IL-13 (10 ng/mL each) in vitro, as evidenced by the expression of the CD206 and IL-10 markers. In addition, Trx-1 induced downregulation of nuclear translocation of activator protein-1 and Ref-1, and significantly reduced the lipopolysaccharide-induced differentiation of inflammatory M1 macrophages, as indicated by the decreased expression of the M1 cytokines, tumor necrosis factor-α and monocyte chemoattractant protein-1. Consistently, Trx-1 administered to hyperlipoproteinemic ApoE2.Ki mice at 30 µg/30 g body weight challenged either with lipopolysaccharide at 30 µg/30 g body weight or with IL-4 at 500 ng/30 g body weight significantly induced the M2 phenotype while inhibiting differentiation of macrophages into the M1 phenotype in liver and thymus. ApoE2.Ki mice challenged once weekly with lipopolysaccharide for 5 weeks developed severe atherosclerotic lesions enriched with macrophages expressing predominantly M1 over M2 markers. In contrast, however, daily injections of Trx-1 shifted the phenotype pattern of lesional macrophages in these animals to predominantly M2 over M1, and the aortic lesion area was significantly reduced (from 100%±18% to 62.8%±9.8%; n=8; P<0.01). Consistently, Trx-1 colocalized with M2 but not with M1 macrophage markers in human atherosclerotic vessel specimens. CONCLUSIONS: The ability of Trx-1 to promote differentiation of macrophages into an alternative, anti-inflammatory phenotype may explain its protective effects in cardiovascular diseases. These data provide novel insight into the link between oxidative stress and cardiovascular diseases.
Subject(s)
Anti-Inflammatory Agents/pharmacology , Aortic Diseases/prevention & control , Atherosclerosis/prevention & control , Cell Differentiation/drug effects , Macrophages, Peritoneal/drug effects , Thioredoxins/pharmacology , Animals , Aortic Diseases/chemically induced , Aortic Diseases/genetics , Aortic Diseases/immunology , Aortic Diseases/metabolism , Aortic Diseases/pathology , Apolipoprotein E2/genetics , Apolipoprotein E2/metabolism , Atherosclerosis/chemically induced , Atherosclerosis/genetics , Atherosclerosis/immunology , Atherosclerosis/metabolism , Atherosclerosis/pathology , Biomarkers/metabolism , Cyclin-Dependent Kinase Inhibitor p16/metabolism , Cytokines/metabolism , DNA-(Apurinic or Apyrimidinic Site) Lyase/metabolism , Disease Models, Animal , Humans , Inflammation Mediators/metabolism , Lectins, C-Type/metabolism , Lipopolysaccharides , Macrophages, Peritoneal/immunology , Macrophages, Peritoneal/metabolism , Macrophages, Peritoneal/pathology , Mannose Receptor , Mannose-Binding Lectins/metabolism , Mice , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , Phenotype , Receptors, Cell Surface/metabolism , Recombinant Proteins/pharmacology , Time Factors , Transcription Factor AP-1/metabolismABSTRACT
At present, there are three ways to determine effectively the quality of the cryopreservation procedure using ovarian tissue before the re-implantation treatment: evaluation of follicles after post-thawing xenotransplantation to SCID mouse, in-vitro culture in a large volume of culture medium under constant agitation and culture on embryonic chorio-allantoic membrane within a hen's eggs. The aim of this study was to compare the two methods, culture in vitro and culture on embryonic chorioallantoic membrane (CAM) of cryopreserved human ovarian medulla-contained and medulla-free cortex. Ovarian fragments were divided into small pieces (1.5-2.0×1.0-1.2×0.8-1.5) of two types, cortex with medulla and medulla-free cortex, frozen, thawed and randomly divided into the following four groups. Group 1: medulla-free cortex cultured in vitro for 8 days in large volume of medium with mechanical agitation, Group 2: medulla-containing cortex cultured in vitro, Group 3: medulla-free cortex cultured in CAM-system for 5 days, Group 4: medulla-containing cortex cultured in CAM-system. The efficacy of the tissue culture was evaluated by the development of follicles and by intensiveness of angiogenesis in the tissue (von Willebrand factor and Desmin). For Group 1, 2, 3 and 4, respectively 85%, 85%, 87% and 84% of the follicles were morphologically normal (P>0.1). The immunohistochemical analysis showed that angiogenesis detected by von Willebrand factor was lower in groups 1 and 3 (medulla-free cortex). Neo-vascularisation (by Desmin) was observed only in ovarian tissue of Group 4 (medulla-contained cortex after CAM-culture). It appears that the presence of medulla in ovarian pieces is beneficial for post-thaw development of cryopreserved human ovarian tissue. For medical practice it is recommended for evaluation of post-warming ovarian tissue to use the CAM-system as a valuable alternative to xenotransplantation and for cryopreservation of these tissues to prepare ovarian medulla-contained strips.
Subject(s)
Chorioallantoic Membrane/physiology , Cryopreservation/methods , Ovary/physiology , Tissue Culture Techniques/methods , Adolescent , Adult , Animals , Chick Embryo , Desmin/analysis , Female , Humans , Immunohistochemistry , Mice , Mice, SCID , Neovascularization, Physiologic , Ovarian Follicle/growth & development , Ovarian Follicle/metabolism , Ovarian Follicle/transplantation , Ovary/blood supply , Ovary/transplantation , Reproducibility of Results , Time Factors , Transplantation, Heterologous , Young Adult , von Willebrand Factor/analysisABSTRACT
Previous efforts to develop drugs that directly inhibit the activity of mutant KRAS, the most commonly mutated human oncogene, have not been successful. Cancer cells driven by mutant KRAS require expression of the serine/threonine kinase STK33 for their viability and proliferation, identifying STK33 as a context-dependent therapeutic target. However, specific strategies for interfering with the critical functions of STK33 are not yet available. Here, using a mass spectrometry-based screen for STK33 protein interaction partners, we report that the HSP90/CDC37 chaperone complex binds to and stabilizes STK33 in human cancer cells. Pharmacologic inhibition of HSP90, using structurally divergent small molecules currently in clinical development, induced proteasome-mediated degradation of STK33 in human cancer cells of various tissue origin in vitro and in vivo, and triggered apoptosis preferentially in KRAS mutant cells in an STK33-dependent manner. Furthermore, HSP90 inhibitor treatment impaired sphere formation and viability of primary human colon tumor-initiating cells harboring mutant KRAS. These findings provide mechanistic insight into the activity of HSP90 inhibitors in KRAS mutant cancer cells, indicate that the enhanced requirement for STK33 can be exploited to target mutant KRAS-driven tumors, and identify STK33 depletion through HSP90 inhibition as a biomarker-guided therapeutic strategy with immediate translational potential.
Subject(s)
HSP90 Heat-Shock Proteins/antagonists & inhibitors , Mutation , Protein Serine-Threonine Kinases/metabolism , Proto-Oncogene Proteins/genetics , ras Proteins/genetics , Apoptosis , Cell Line, Tumor , Colonic Neoplasms/drug therapy , Colonic Neoplasms/pathology , Humans , Proteasome Endopeptidase Complex/physiology , Proto-Oncogene Proteins/physiology , Proto-Oncogene Proteins p21(ras) , Ubiquitination , ras Proteins/physiologyABSTRACT
In order to generate genomic signals, the androgen receptor (AR) has to be transported into the nucleus upon androgenic stimuli. However, there is evidence from in vitro experiments that in castration-resistant prostate cancer (CRPC) cells the AR is able to translocate into the nucleus in a ligand-independent manner. The recent finding that inhibition of the glycogen-synthase-kinase 3ß (GSK-3ß) induces a rapid nuclear export of the AR in androgen-stimulated prostate cancer cells prompted us to analyze the effects of a GSK-3ß inhibition in the castration-resistant LNCaP sublines C4-2 and LNCaP-SSR. Both cell lines exhibit high levels of nuclear AR in the absence of androgenic stimuli. Exposure of these cells to the maleimide SB216763, a potent GSK-3ß inhibitor, resulted in a rapid nuclear export of the AR even under androgen-deprived conditions. Moreover, the ability of C4-2 and LNCaP-SSR cells to grow in the absence of androgens was diminished after pharmacological inhibition of GSK-3ß in vitro. The ability of SB216763 to modulate AR signalling and function in CRPC in vivo was additionally demonstrated in a modified chick chorioallantoic membrane xenograft assay after systemic delivery of SB216763. Our data suggest that inhibition of GSK-3ß helps target the AR for export from the nucleus thereby diminishing the effects of mislocated AR in CRPC cells. Therefore, inhibition of GSK-3ß could be an interesting new strategy for the treatment of CRPC.
Subject(s)
Glycogen Synthase Kinase 3/antagonists & inhibitors , Orchiectomy , Prostatic Neoplasms/pathology , Prostatic Neoplasms/surgery , Protein Kinase Inhibitors/pharmacology , Receptors, Androgen/metabolism , Active Transport, Cell Nucleus/drug effects , Cell Line, Tumor , Cell Nucleus/drug effects , Cell Nucleus/metabolism , Cell Proliferation/drug effects , Enzyme Activation/drug effects , Gene Silencing , Glycogen Synthase Kinase 3/chemistry , Glycogen Synthase Kinase 3/genetics , Glycogen Synthase Kinase 3/metabolism , Glycogen Synthase Kinase 3 beta , Humans , Indoles/pharmacology , Karyopherins/metabolism , Ligands , Male , Maleimides/pharmacology , Phosphorylation/drug effects , Prostatic Neoplasms/genetics , Prostatic Neoplasms/metabolism , Receptors, Cytoplasmic and Nuclear/metabolism , Signal Transduction/drug effects , Tyrosine/metabolism , Up-Regulation/drug effects , Exportin 1 ProteinABSTRACT
Glioblastoma multiforme, a highly aggressive tumor of the central nervous system, has a dismal prognosis that is due in part to its resistance to radio- and chemotherapy. The protein kinase C (PKC) family of serine threonine kinases has been implicated in the formation and proliferation of glioblastoma multiforme. Members of the protein kinase D (PKD) family, which consists of PKD1, -2 and, -3, are prominent downstream targets of PKCs and could play a major role in glioblastoma growth. PKD2 was highly expressed in both low-grade and high-grade human gliomas. The number of PKD2-positive tumor cells increased with glioma grading (P < .001). PKD2 was also expressed in CD133-positive glioblastoma stem cells and various glioblastoma cell lines in which the kinase was found to be constitutively active. Inhibition of PKDs by pharmacological inhibitors resulted in substantial inhibition of glioblastoma proliferation. Furthermore, specific depletion of PKD2 by siRNA resulted in a marked inhibition of anchorage-dependent and -independent proliferation and an accumulation of glioblastoma cells in G0/G1, accompanied by a down-regulation of cyclin D1 expression. In addition, PKD2-depleted glioblastoma cells exhibited substantially reduced tumor formation in vivo on chicken chorioallantoic membranes. These findings identify PKD2 as a novel mediator of glioblastoma cell growth in vitro and in vivo and thereby as a potential therapeutic target for this devastating disease.
Subject(s)
Brain Neoplasms/pathology , Brain/enzymology , Glioblastoma/pathology , TRPP Cation Channels/metabolism , Animals , Apoptosis , Blotting, Western , Brain Neoplasms/enzymology , Cell Cycle , Cell Proliferation , Chickens , Chorioallantoic Membrane/metabolism , Cyclin D1/metabolism , Glioblastoma/enzymology , Humans , Immunoenzyme Techniques , RNA, Small Interfering/genetics , TRPP Cation Channels/antagonists & inhibitors , TRPP Cation Channels/geneticsABSTRACT
BACKGROUND: Tumour angiogenesis is crucially dependent on the communication between the tumour and the associated endothelium. Protein kinase D (PKD) isoenzymes mediate vascular endothelial growth factor-A (VEGF-A) induced endothelial cell proliferation and migration and are also highly expressed in various tumours. AIM: To examine the role of PKDs for tumour proliferation and angiogenesis selectively in pancreatic and gastric tumours and in tumour-associated endothelium in vitro and in vivo. METHODS: PKD2 expression in human tumours was determined by immunohistochemistry. The effect of PKD2 depletion in endothelial cells by siRNAs was examined in sprouting assays, the chorioallantois model (CAM) and tumour xenografts. In murine endothelium in vivo PKD2 was knocked-down by splice switching oligonucleotides. Human PKD2 was depleted in xenografts by siRNAs and PKD2-miRs. PKD2 activation by hypoxia and its role for hypoxia-induced NR4/TR3- and VEGF-A promoter activity, expression and secretion was investigated in cell lines. RESULTS: PKD2 is expressed in gastrointestinal tumours and in the tumour-associated endothelium. Tumour growth and angiogenesis in the CAM and in tumour xenografts require PKD expression in endothelial cells. Conversely, hypoxia activates PKD2 in pancreatic cancer cells and PKD2 was identified as the major mediator of hypoxia-stimulated VEGF-A promoter activity, expression and secretion in tumour cells. PKD2 depletion in pancreatic tumours inhibited tumour-driven blood vessel formation and tumour growth in the CAM and in orthotopic pancreatic cancer xenografts. CONCLUSION: PKD2 regulates hypoxia-induced VEGF-A expression/secretion by tumour cells and VEGF-A stimulated blood vessel formation. PKD2 is a novel, essential mediator of tumour cell-endothelial cell communication and a promising therapeutic target to inhibit angiogenesis in gastrointestinal cancers.
Subject(s)
Gastrointestinal Neoplasms/pathology , Protein Kinases/physiology , Animals , Cell Communication/physiology , Chick Embryo , Chorioallantoic Membrane/blood supply , Chorioallantoic Membrane/enzymology , Coculture Techniques , Endothelial Cells/pathology , Endothelium, Vascular/enzymology , Gastrointestinal Neoplasms/blood supply , Gastrointestinal Neoplasms/enzymology , Gene Knockdown Techniques , Humans , Mice , Mice, Nude , Neoplasm Transplantation , Neovascularization, Pathologic/enzymology , Neovascularization, Pathologic/pathology , Pancreatic Neoplasms/blood supply , Pancreatic Neoplasms/enzymology , Pancreatic Neoplasms/pathology , Protein Kinase D2 , Protein Kinases/genetics , Protein Kinases/metabolism , Transplantation, Heterologous , Tumor Cells, Cultured , Vascular Endothelial Growth Factor A/physiologyABSTRACT
OBJECTIVE: Dendritic cells (DC) accumulate in atherosclerotic arteries where they can modulate atherogenesis. We investigated whether plasmin might alter the function of human DC. METHODS AND RESULTS: Stimulation of monocyte-derived DC with plasmin elicited a time-dependent actin polymerization and chemotaxis comparable to that triggered by the standard chemoattractant formyl-methionyl-leucyl-phenylalanine. Plasmin triggered rapid activation of Akt and mitogen-activated protein kinases, followed by phosphorylation of the regulatory myosin light chain and chemotaxis. For the chemotactic DC migration, the activation of Akt and p38 and extracellular signal-regulated kinase 1/2 mitogen-activated protein kinases were indispensable, as shown by pharmacological inhibitors. DC express Akt1 and Akt2, but not Akt3. However, in DC, plasmin activates exclusively Akt2 via a p38 mitogen-activated protein kinase-dependent pathway. Accordingly, knockdown of Akt2 with short-hairpin RNA, but not of Akt1, blocked the plasmin-induced extracellular signal-regulated kinase 1/2 activation and the chemotactic response. Moreover, plasmin-stimulated DC induced polarization of CD4(+) T cells toward the interferon-gamma-producing, proinflammatory Th1 phenotype. Consistent with a role for DC and adaptive immune response in atherogenesis, we demonstrate DC in human atherosclerotic vessels and show that plasmin is abundant in human atherosclerotic lesions, where it colocalizes with DC. CONCLUSIONS: Plasmin generation in the atherosclerotic vessel wall might contribute to accumulation of DC, activation of the adaptive immune response, and aggravation of atherosclerosis.
Subject(s)
Chemotaxis/physiology , Dendritic Cells/metabolism , Fibrinolysin/metabolism , Monocytes/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction/physiology , Annexin A2/metabolism , Aorta/metabolism , Aorta/pathology , Atherosclerosis/metabolism , Atherosclerosis/pathology , Cell Movement/drug effects , Chemotaxis/drug effects , Dendritic Cells/pathology , Fibrinolysin/pharmacology , Humans , Mitogen-Activated Protein Kinase Kinases/metabolism , Monocytes/pathology , T-Lymphocytes, Helper-Inducer/metabolism , T-Lymphocytes, Helper-Inducer/pathologyABSTRACT
RhoA and RhoC are highly related Rho GTPases, but differentially control cellular behaviour. We combined molecular, cellular, and biochemical experiments to characterise differences between these highly similar GTPases. Our findings demonstrate that enhanced expression of RhoC results in a striking increase in the migration and invasion of pancreatic carcinoma cells, whereas forced expression of RhoA decreases these actions. These isoform-specific functions correlate with differences in the cellular activity of RhoA and RhoC in human cells, with RhoC being more active than RhoA in activity assays and serum-response factor-dependent gene transcription. Subcellular localisation studies revealed that RhoC is predominantly localised in the membrane-containing fraction, whereas RhoA is mainly localised in the cytoplasmic fraction. These differences are not mediated by a different interaction with RhoGDIs. In vitro GTP/GDP binding analyses demonstrate different affinity of RhoC for GTP[S] and faster intrinsic and guanine nucleotide exchange factor (GEF)-stimulated GDP/GTP exchange rates compared to RhoA. Moreover, the catalytic domains of SopE and Dbs are efficacious GEFs for RhoC. mRNA expression of RhoC is markedly enhanced in advanced pancreatic cancer stages, and thus the differences discovered between RhoA and RhoC might provide explanations for their different influences on cell migration and tumour invasion.
Subject(s)
Cell Movement , Neoplasm Invasiveness , Pancreatic Neoplasms/pathology , rho GTP-Binding Proteins/metabolism , rhoA GTP-Binding Protein/metabolism , Cell Line, Tumor , Deep Brain Stimulation , Humans , Pancreatic Neoplasms/metabolism , Protein Isoforms/chemistry , Protein Isoforms/genetics , Protein Isoforms/metabolism , RNA, Messenger/metabolism , Reverse Transcriptase Polymerase Chain Reaction , rap GTP-Binding Proteins/chemistry , rap GTP-Binding Proteins/genetics , rap GTP-Binding Proteins/metabolism , rho GTP-Binding Proteins/chemistry , rho GTP-Binding Proteins/genetics , rhoA GTP-Binding Protein/chemistry , rhoA GTP-Binding Protein/genetics , rhoC GTP-Binding ProteinABSTRACT
Evasion of apoptosis is a characteristic feature of pancreatic cancer, a prototypic cancer that is refractory to current treatment approaches. Hence, there is an urgent need to design rational strategies that counter apoptosis resistance. To explore X-linked inhibitor of apoptosis (XIAP) as a therapeutic target in pancreatic cancer, we analyzed the expression of XIAP in pancreatic tumor samples and evaluated the effect of small molecule XIAP inhibitors alone and in combination with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) against pancreatic carcinoma in vitro and in vivo. Here, we report that XIAP is highly expressed in pancreatic adenocarcinoma samples compared with normal pancreatic ducts. Small molecule XIAP inhibitors synergize with TRAIL to induce apoptosis and to inhibit long-term clonogenic survival of pancreatic carcinoma cells. In contrast, they do not reverse the lack of toxicity of TRAIL on nonmalignant cells in vitro or normal tissues in vivo, pointing to a therapeutic index. Most importantly, XIAP inhibitors cooperate with TRAIL to trigger apoptosis and suppress pancreatic carcinoma growth in vivo in two preclinical models, i.e., the chorioallantoic membrane model and a mouse xenograft model. Parallel immunohistochemical analysis of tumor tissue under therapy reveals that the XIAP inhibitor acts in concert with TRAIL to cause caspase-3 activation and apoptosis. In conclusion, our findings provide, for the first time, evidence in vivo that XIAP inhibitors prime pancreatic carcinoma cells for TRAIL-induced apoptosis and potentiate the antitumor activity of TRAIL against established pancreatic carcinoma. These findings build the rationale for further (pre)clinical development of XIAP inhibitors and TRAIL against pancreatic cancer.