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1.
Sci Rep ; 8(1): 7794, 2018 05 17.
Article in English | MEDLINE | ID: mdl-29773831

ABSTRACT

DNAJC17 is a heat shock protein (HSP40) family member, identified in mouse as susceptibility gene for congenital hypothyroidism. DNAJC17 knockout mouse embryos die prior to implantation. In humans, germline homozygous mutations in DNAJC17 have been found in syndromic retinal dystrophy patients, while heterozygous mutations represent candidate pathogenic events for myeloproliferative disorders. Despite widespread expression and involvement in human diseases, DNAJC17 function is still poorly understood. Herein, we have investigated its function through high-throughput transcriptomic and proteomic approaches. DNAJC17-depleted cells transcriptome highlighted genes involved in general functional categories, mainly related to gene expression. Conversely, DNAJC17 interactome can be classified in very specific functional networks, with the most enriched one including proteins involved in splicing. Furthermore, several splicing-related interactors, were independently validated by co-immunoprecipitation and in vivo co-localization. Accordingly, co-localization of DNAJC17 with SC35, a marker of nuclear speckles, further supported its interaction with spliceosomal components. Lastly, DNAJC17 up-regulation enhanced splicing efficiency of minigene reporter in live cells, while its knockdown induced perturbations of splicing efficiency at whole genome level, as demonstrated by specific analysis of RNAseq data. In conclusion, our study strongly suggests a role of DNAJC17 in splicing-related processes and provides support to its recognized essential function in early development.


Subject(s)
HSP40 Heat-Shock Proteins/metabolism , Alternative Splicing , Cell Nucleus/metabolism , HSP40 Heat-Shock Proteins/analysis , HSP40 Heat-Shock Proteins/genetics , HeLa Cells , Humans , Protein Interaction Mapping , Proteomics , Spliceosomes/metabolism
2.
J Dermatolog Treat ; 29(2): 149-151, 2018 Mar.
Article in English | MEDLINE | ID: mdl-28604133

ABSTRACT

BACKGROUND: Androgenetic alopecia (AGA) is a common form of scalp hair loss that affects up to 50% of males between 18 and 40 years old. Several molecules are commonly used for the treatment of AGA, acting on different steps of its pathogenesis (Minoxidil, Finasteride, Serenoa repens) and show some side effects. In literature, on the basis of hypertrichosis observed in patients treated with analogues of prostaglandin PGF2a, it was supposed that prostaglandins would have an important role in the hair growth: PGE and PGF2a play a positive role, while PGD2 a negative one. OBJECTIVE: We carried out a pilot study to evaluate the efficacy of topical cetirizine versus placebo in patients with AGA. PATIENTS AND METHODS: A sample of 85 patients was recruited, of which 67 were used to assess the effectiveness of the treatment with topical cetirizine, while 18 were control patients. RESULTS: We found that the main effect of cetirizine was an increase in total hair density, terminal hair density and diameter variation from T0 to T1, while the vellus hair density shows an evident decrease. The use of a molecule as cetirizine, with no notable side effects, makes possible a good compliance by patients. CONCLUSION: Our results have shown that topical cetirizine 1% is responsible for a significant improvement of the initial framework of AGA.


Subject(s)
Alopecia/drug therapy , Cetirizine/therapeutic use , Histamine H1 Antagonists, Non-Sedating/therapeutic use , Administration, Topical , Adult , Aged , Female , Humans , Male , Middle Aged , Pilot Projects , Placebo Effect , Treatment Outcome , Young Adult
4.
J Photochem Photobiol B ; 162: 72-76, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27344021

ABSTRACT

Actinic keratosis (AK) is a keratinocyte intraepidermal neoplasia UV light-induced that frequently appears in sun-exposed areas of the skin. Although historically AK was defined as "precancerous", actually it is considered as the earliest stage of squamous cell carcinoma (SCC) in situ. Since AKs can progress into invasive SCC, their treatment is recommended. AKs rarely develop as a single lesion; usually multiple lesions commonly affect an entire area of chronically actinic damaged skin. This has led to the concept of "field cancerization", an area chronically sun-exposed that surrounds peripherally visible lesions, in which are individualized subclinical alterations. One of the main principles endpoint in the management of AKs is the evaluation and the treatment of field cancerization. In this view, in order to detect and quantify field cancerization, we employed a method based on the topical application of methyl aminolevulinate (MAL) and the detection of the fluorescence emitted by its metabolite Protoporphyrin IX (PpIX); then, considering the extension and the intensity of measured fluorescence, we create a score of field cancerization. The results show that patients underwent to daylight PDT had a reduction of total score, from T0 to T2. Whereas in the group untreated we observed a stability of total score or a slightly worse. So, the method and the score used allows to evaluate with a good approximation the dimension of field cancerization and show the modification of it after treatment.


Subject(s)
Aminolevulinic Acid/analogs & derivatives , Carcinoma, Squamous Cell/pathology , Dermoscopy , Keratosis, Actinic/diagnosis , Photosensitizing Agents/therapeutic use , Skin Neoplasms/pathology , Aged , Aminolevulinic Acid/therapeutic use , Humans , Keratosis, Actinic/drug therapy , Keratosis, Actinic/pathology , Middle Aged
5.
G Chir ; 35(3-4): 61-4, 2014.
Article in English | MEDLINE | ID: mdl-24841679

ABSTRACT

INTRODUCTION: Currently the most widely used methods for endoscopic control of esophageal varices bleeding are sclerotherapy and rubber band ligation. Although the superiority of band ligation (BL) over endoscopic sclerotherapy (SCL) for the secondary prophylaxis of variceal hemorrhage has been proven, the best approach for acute bleeding remains controversial. PATIENTS AND METHODS: We performed a retrospective study between January 2005 and May 2013. We selected 104 patients with gastrointestinal hemorrhage from rupture of esophageal varices treated with endoscopic sclerotherapy. The sclerosing agent used was 1% polidocanol in 89 cases, butyl-cyanoacrylate in 8 cases and sodium tetradecylsulfate in 4 cases. In 3 cases had not been carried sclerosis because it was not possible to identify the bleeding site. RESULTS: Among the 101 patients who underwent endoscopic sclerotherapy 4 presented re-bleeding within 12 hours from first treatment. Other 10 patients (9.9%) presented re-bleeding within a 5-days period. The most frequent complication was ulceration, observed in 4 cases (3.8%). There was only one case of perforation treated conservatively. CONCLUSIONS: The general improvement in the results of the treatment of variceal acute bleeding might be attributed to better clinical management of these patients. In literature no consensus exists regarding the preferred endoscopic treatment. To date, there is no single method applicable to all patients with bleeding esophageal varices, but sclerotherapy is considered effective, safe and repeatable in experienced hands.


Subject(s)
Enbucrilate/administration & dosage , Esophageal and Gastric Varices/therapy , Esophagoscopy , Gastrointestinal Hemorrhage/therapy , Polyethylene Glycols/administration & dosage , Sclerosing Solutions/administration & dosage , Sclerotherapy , Sodium Tetradecyl Sulfate/administration & dosage , Adult , Aged , Esophageal and Gastric Varices/complications , Female , Gastrointestinal Hemorrhage/etiology , Humans , Ligation/methods , Male , Middle Aged , Polidocanol , Recurrence , Reproducibility of Results , Retrospective Studies , Sclerotherapy/methods , Treatment Outcome
6.
G Chir ; 34(5-6): 180-2, 2013.
Article in English | MEDLINE | ID: mdl-23837960

ABSTRACT

AIM: To evaluate the safety and efficacy of the minimally invasive surgical approach (laparoscopic drainage) of liver abscesses in selected cases. CASE REPORT: Male, 58 years old, from a rural area, presented with epigastric abdominal pain, fever, weight loss, loss of appetite, a palpable mass in the epigastrium and neutrophilic leukocytosis. CT revealed a complex multiloculated liver abscess in segments 2-3. Systemic antibiotic therapy alone was ineffective; percutaneous drainage was excluded due to the characteristics of the lesion. RESULT: Given the complexity of the lesion, a laparoscopic approach was chosen involving complete drainage of the abscess, debridement and irrigation; the cavity was unroofed using electrocautery and samples were obtained for bacterial culture and drug testing. Two drains were left in the cavity for seven days. No complications were observed. DISCUSSION: In accordance with the scientific literature, after thorough imaging we performed laparoscopic drainage of a large, complex liver abscess as a safe, effective alternative to open surgery when antibiotic therapy alone failed and percutaneous drainage was uncertain. CONCLUSION: Not all liver abscesses can be treated with antibiotic therapy or percutaneous drainage. Laparoscopic drainage in association with systemic antibiotic therapy is a safe and effective minimally invasive approach that should be considered in selected patients.


Subject(s)
Drainage/methods , Laparoscopy , Liver Abscess/surgery , Anti-Bacterial Agents , Humans , Male , Middle Aged
7.
Oncogene ; 32(35): 4110-9, 2013 Aug 29.
Article in English | MEDLINE | ID: mdl-23027131

ABSTRACT

Aberrant motility and invasive ability are relevant hallmarks of malignant tumor cells. Pathways regulating the movement of cancer cells from the site of primary tumor toward adjacent and/or distant tissues are not entirely defined. By using a model of malignant transformation induced by Ras, we identified Wnt4 as an early target of Ras oncogenic signaling. Here we show that Wnt4 is repressed by Ras and that forced Wnt4 expression inhibits Ras-induced cell motility. Accordingly, we found that Wnt4 is downregulated in human anaplastic thyroid carcinomas, the most malignant and metastatic thyroid cancer histotype. Wnt4 interferes with Ras-induced actin cytoskeleton reorganization through non-canonical pathways, by altering the balance between the activation of different Rho-family small guanosine triphosphatases (GTPases). Finally, we demonstrate that Wnt4 is post-transcriptionally repressed by miR-24, a Ras-induced micro RNA (miRNA) targeting the 3'-untranslated region (UTR) of Wnt4. Taken together our data highlight a novel Ras-regulated miRNA-dependent circuitry regulating the motile phenotype of cancer cells.


Subject(s)
Cell Movement , Cell Transformation, Neoplastic , Genes, ras , Thyroid Gland/pathology , Wnt4 Protein/physiology , Animals , Cytoskeleton/chemistry , Humans , Phosphatidylinositol 3-Kinases/physiology , Rats , Thyroid Neoplasms/pathology
8.
Article in English | MEDLINE | ID: mdl-24483577

ABSTRACT

We present a signed measure analysis of compressible Hall magnetohydrodynamic turbulence with an external guide field. Signed measure analysis allows us to characterize the scaling behavior of the sign-oscillating flow structures and their geometrical properties (fractal dimensions of structures). A reduced numerical model, valid when a strong guide magnetic field is present, is used here. In order to discuss the effect of the Hall term, different values for the ion skin depth are considered in the simulations. Results show that as the Hall term is increased, the fractal dimension of the current and vorticity sheets decreases. This observation, together with previous analysis of the same fields, provides a comprehensive description of the effect of the Hall force on the formation of structures. Two main processes are identified, namely, the widening and unraveling of the sheets.

9.
G Chir ; 34(9-10): 249-53, 2013.
Article in English | MEDLINE | ID: mdl-24629808

ABSTRACT

INTRODUCTION: The aim of this study was to compare the results of classic laparoscopic, three-port and SILS cholecystectomy. MATERIALS AND METHODS: We conducted a retrospective study of data collected between January 2010 and December 2012 pertaining to 159 selected patients with symptomatic gallstones. 57 underwent laparoscopic cholecystectomy, 51 three-port cholecystectomy and 48 SILS cholecystectomy. We then compared the groups with respect to mean operating time, intraoperative complications, postoperative pain, duration of hospitalization and final aesthetic result. RESULTS: The mean operating time was significantly higher in the SILS cholecystectomy group (93 minutes) than in the other two groups. There were no intraoperative complications. There were no significant differences in the duration of hospitalization among the three groups. Patients in the SILS cholecystectomy group reported significantly less pain 3, 6 and 12 hours after surgery. The aesthetic results at 1 and 6 months' follow-up were also decidedly better. CONCLUSIONS: On the basis of this study, SILS cholecystectomy is a feasible, safe procedure. In any case, it should be used in selected patients only and carried out by a dedicated team with strong experience in laparoscopy. The main advantages of this technique are a reduction in post-operative pain and improved aesthetic result, at the price, however, of its greater technical difficulty and longer operating times. Future studies are in any case necessary to evaluate any other benefits of this method.


Subject(s)
Cholecystectomy, Laparoscopic/methods , Cholelithiasis/surgery , Adolescent , Adult , Aged , Aged, 80 and over , Cholecystectomy , Feasibility Studies , Female , Follow-Up Studies , Humans , Length of Stay , Male , Middle Aged , Retrospective Studies , Treatment Outcome
10.
Oncogene ; 30(3): 275-86, 2011 Jan 20.
Article in English | MEDLINE | ID: mdl-20956945

ABSTRACT

miR-21 is a microRNA (miRNA) frequently overexpressed in human cancers. Here we show that miR-21 is upregulated both in vitro and in vivo by oncogenic Ras, thus linking this miRNA to one of the most frequently activated oncogenes in human cancers. Ras regulation of miR-21 occurs with a delayed kinetic and requires at least two Ras downstream pathways. A screen of human thyroid cancers and non-small-cell lung cancers for the expression of miR-21 reveals that it is overexpressed mainly in anaplastic thyroid carcinomas, the most aggressive form of thyroid cancer, whereas in lung its overexpression appears to be inversely correlated with tumor progression. We also show that a LNA directed against miR-21 slows down tumor growth in mice. Consistently, a search for mRNAs downregulated by miR-21 shows an enrichment for mRNAs encoding cell cycle checkpoints regulators, suggesting an important role for miR-21 in oncogenic Ras-induced cell proliferation.


Subject(s)
Cell Division/physiology , MicroRNAs/physiology , Neoplasms/pathology , Proto-Oncogene Proteins p21(ras)/physiology , Up-Regulation/physiology , Animals , Cell Line, Tumor , Cell Transformation, Neoplastic , DNA Damage , Gene Knockdown Techniques , Humans , Mice , MicroRNAs/genetics
11.
Int J Androl ; 34(1): 41-8, 2011 Feb.
Article in English | MEDLINE | ID: mdl-20345874

ABSTRACT

Although it is well established that all the aspects of male reproduction are hormonally regulated, the endocrine control of the ejaculatory reflex is still not completely clarified. Sex steroids, thyroid and pituitary hormones (oxytocin and prolactin) have been proposed to control the ejaculatory process at various levels; however, only a few reports are currently available. The aim of this study was to evaluate the contribution of testosterone, thyrotropin (TSH) and prolactin (PRL) in the pathogenesis of ejaculatory dysfunction in a large series of subjects consulting for sexual dysfunction. Among the 2652 patients studied, 674 (25.2%) and 194 (7.3%) reported premature and delayed ejaculation (PE and DE), respectively. Categorizing ejaculatory difficulties on an eight-point scale starting from severe PE and ending with anejaculation (0 = severe PE, 1 = moderate PE, 2 = mild PE, 3 = no difficulties, 4 = mild DE, 5 = moderate DE, 6 = severe DE and 7 = anejaculation), PRL as well as TSH levels progressively increased from patients with severe PE towards those with anejaculation. Conversely, the opposite was observed for testosterone levels. All of these associations were confirmed after adjustment for age (adjusted r = 0.050, 0.053 and -0.038 for PRL, TSH and testosterone, respectively; all p < 0.05). When all hormonal parameters were introduced in the same regression model, adjusting for age, ΣMHQ (an index of general psychopathology) and use of selective serotonin reuptake inhibitor antidepressants, they were independently associated with ejaculatory problems (adjusted r = 0.056, 0.047 and -0.059 for PRL, TSH and testosterone, respectively; all p < 0.05). This study indicates endocrine system is involved in the control of ejaculatory function and that PRL, TSH and testosterone play an independent role.


Subject(s)
Ejaculation/physiology , Prolactin/blood , Sexual Dysfunction, Physiological/physiopathology , Testosterone/blood , Thyrotropin/blood , Adult , Aging , Humans , Male , Middle Aged , Orgasm , Sexual Dysfunction, Physiological/etiology , Thyroid Gland/physiology
12.
Vet Pathol ; 46(4): 589-97, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19276057

ABSTRACT

The equine sarcoid is the most common dermatologic neoplasm reported in horses. Bovine papillomavirus (BPV) types 1 and 2 are associated with sarcoids, in which the expression of the major transforming oncoprotein (E5) is often recorded. The transformation activity of the virus is due to the binding of the E5 to the platelet-derived growth factor beta receptor (PDGFbeta-r). In the present study, we show by Western blot in 4 sarcoid samples and 3 normal equine skin samples that the PDGFbeta-r is more phosphorylated in sarcoid tissue than in normal skin (P < .001). Furthermore, the physical interaction between the activated receptor and the 85-kDa regulatory subunit (p85) of phosphatidylinositol-3-kinase (PI3K) is shown by coimmunoprecipitation. The PI3K-AKT-cyclin D3 molecular pathway downstream to the activation of the PDGFbeta-r is shown to be expressed, and the amount of the investigated molecules is higher than normal (P < .001), suggesting an activation of these effectors in sarcoids. Further, we demonstrate that phospho-JNK and phospho-JUN are more expressed in sarcoids than in normal skin. Our results provide new insights into the pathogenesis of equine sarcoids and support the validity of this in-vivo model to further characterize the molecular pathways underlying BPV E5-induced carcinogenesis.


Subject(s)
Horse Diseases/metabolism , Oncogene Proteins, Viral/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Receptor, Platelet-Derived Growth Factor beta/metabolism , Skin Neoplasms/veterinary , Animals , Blotting, Western/veterinary , Electrophoresis, Polyacrylamide Gel/veterinary , Horse Diseases/virology , Horses , Immunoprecipitation/veterinary , Phosphorylation , Skin Neoplasms/metabolism , Skin Neoplasms/virology
13.
Oncogene ; 28(1): 73-84, 2009 Jan 08.
Article in English | MEDLINE | ID: mdl-18850008

ABSTRACT

The transcription factor AP-1 plays key roles in tumorigenesis, by regulating a variety of protein-coding genes, implicated in multiple hallmarks of cancer. Among non-coding genes, no AP-1 target has been described yet in tumorigenesis. MicroRNAs (miRNAs) are negative post-transcriptional regulators of protein-coding genes. miRNA expression signatures are highly relevant in cancer and several tumor-associated miRNAs (oncomirs) play critical roles in oncogenesis. Here, we show that the miRNA miR-21, which represents the most frequently upregulated oncomir in solid tumors, is induced by AP-1 in response to RAS. By analyzing validated miR-21 targets, we have found that the tumor suppressors PTEN and PDCD4 are downregulated by RAS in an AP-1- and miR-21-dependent fashion. We further show that, given the role of PDCD4 as negative regulator of AP-1, the miR-21-mediated downregulation of PDCD4 is essential for the maximal induction of AP-1 activity in response to RAS. Our data reveal a novel mechanism of positive autoregulation of the AP-1 complex in RAS transformation and disclose the function of oncomirs as critical targets and regulators of AP-1 in tumorigenesis.


Subject(s)
Apoptosis Regulatory Proteins/metabolism , Cell Transformation, Neoplastic/metabolism , MicroRNAs/metabolism , Transcription Factor AP-1/metabolism , ras Proteins/metabolism , Animals , Apoptosis Regulatory Proteins/genetics , Cell Line, Tumor , Cell Survival , Cell Transformation, Neoplastic/genetics , Homeostasis , Humans , MicroRNAs/genetics , PTEN Phosphohydrolase/genetics , PTEN Phosphohydrolase/metabolism , Proto-Oncogene Proteins c-fos/metabolism , Proto-Oncogene Proteins c-jun/metabolism , Rats , Thyroid Gland/metabolism , Thyroid Gland/pathology , Transcription Factor AP-1/genetics , ras Proteins/genetics
14.
Oncogene ; 20(2): 209-18, 2001 Jan 11.
Article in English | MEDLINE | ID: mdl-11313948

ABSTRACT

Tyrosine 1062 of Ret, which represents an intracytoplasmic docking site for multiple signaling molecules, is essential for Ret-mediated activation of phosphatidylinositol 3-Kinase (PI3-K). PI3-K, in turn, has been implicated in inducing cell survival and neoplastic transformation mediated by Ret. We have examined the mechanisms by which Ret stimulates PI3-K. Here we show that the Insulin Receptor Substrate-1 (IRS-1) is tyrosine phosphorylated and associated with the p85 regulatory subunit of PI3-K in response to Ret activation. IRS-1 coimmunoprecipitates with Ret and co-expression of IRS-1 results in the potentiation of Ret-mediated activation of Akt(PKB), a bona fide effector of PI3-K. The association with the PTB domain of IRS-1 depends on the phosphorylation of tyrosine 1062 of Ret. The deletion of asparagine 1059 (delN1059) and the substitution of leucine 1061 (L1061P), two Ret mutations identified in families affected by congenital megacolon (Hirschsprung's disease), impair the binding of IRS-1 to Ret as well as Ret-mediated Akt(PKB) stimulation. Finally, we show that Shc, which was previously identified as another ligand of Y1062 of Ret, competes with IRS-1 for the binding to Ret pY1062. All together, these findings suggest that IRS-1 is a component of the signaling pathway which leads to Ret-mediated PI3-K activation, a pathway which can be targeted by Hirschsprung-associated Ret mutations. The alternative binding of Shc and IRS-1 to Ret pY1062 can be a system to modulate the activation of different intracellular signaling pathways and to elicit different biological responses following Ret activation.


Subject(s)
Drosophila Proteins , Phosphatidylinositol 3-Kinases/metabolism , Phosphoproteins/metabolism , Protein Serine-Threonine Kinases , Proto-Oncogene Proteins/metabolism , Receptor Protein-Tyrosine Kinases/metabolism , 3T3 Cells , Amino Acid Motifs , Amino Acid Substitution , Animals , Binding Sites , Binding, Competitive , Insulin Receptor Substrate Proteins , Mice , Mutation , Phosphoproteins/genetics , Phosphorylation , Polypyrimidine Tract-Binding Protein , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins c-akt , Proto-Oncogene Proteins c-ret , RNA-Binding Proteins/metabolism , Receptor Protein-Tyrosine Kinases/genetics , Ribonucleoproteins/metabolism
15.
Cancer Res ; 60(14): 3727-31, 2000 Jul 15.
Article in English | MEDLINE | ID: mdl-10919641

ABSTRACT

The RET tyrosine kinase is a functional receptor for neurotrophic ligands of the glial cell line-derived neurotrophic factor (GDNF) family. Loss of function of RET is associated with congenital megacolon or Hirschsprung's disease, whereas germ-line point mutations causing RET activation are responsible for multiple endocrine neoplasia type 2 (MEN2A, MEN2B, and familial medullary thyroid carcinoma) syndromes. Here we show that the expression of a constitutively active RET-MEN2A oncogene promotes survival of rat pheochromocytoma PC12 cells upon growth factor withdrawal. Moreover, we show that the RET-MEN2A-mediated survival depends on signals transduced by the phosphoinositide 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) cascades. Thus, in PC12 cells, RET-MEN2A associates with the PI3K regulatory subunit p85 and promotes activation of Akt (also referred to as protein kinase B) in a PI3K-dependent fashion; in addition, RET-MEN2A promotes MAPK activation. PI3K recruitment and Akt activation as well as MAPK activation depend on RET-MEN2A tyrosine residue 1062. As a result, tyrosine 1062 of RET-MEN2A is essential for RET-MEN2A-mediated survival of PC12 cells cultured in growth factor-depleted media.


Subject(s)
Drosophila Proteins , MAP Kinase Signaling System , Protein Serine-Threonine Kinases , Proto-Oncogene Proteins/metabolism , Receptor Protein-Tyrosine Kinases/metabolism , Tyrosine/metabolism , Animals , Blotting, Western , Cell Survival , Chromones/pharmacology , Culture Media, Serum-Free , DNA Fragmentation , Enzyme Activation , Enzyme Inhibitors/pharmacology , Flavonoids/pharmacology , Glial Cell Line-Derived Neurotrophic Factor Receptors , In Situ Nick-End Labeling , Ligands , Morpholines/pharmacology , Multiple Endocrine Neoplasia Type 2a/genetics , Multiple Endocrine Neoplasia Type 2a/metabolism , PC12 Cells , Phosphatidylinositol 3-Kinases/metabolism , Precipitin Tests , Protein Isoforms , Proto-Oncogene Proteins/chemistry , Proto-Oncogene Proteins c-akt , Proto-Oncogene Proteins c-ret , Rats , Receptor Protein-Tyrosine Kinases/chemistry , Signal Transduction , Transfection
16.
Cancer Res ; 60(14): 3916-20, 2000 Jul 15.
Article in English | MEDLINE | ID: mdl-10919669

ABSTRACT

The Akt/protein kinase B serine/threonine kinase is a downstream effector of phosphoinositide 3-kinase (PI3K). Akt is an important component of mitogenic and antiapoptotic signaling pathways and is implicated in neoplastic transformation. Thyroid cells in culture retain a differentiated phenotype consisting of epithelial cell morphology and the expression of several tissue-specific genes. The survival and proliferation of these cells depend on thyrotropin and a mixture of five additional hormones that includes insulin. The regulation of proliferation and the expression of the thyroid differentiation program are intimately connected processes. As a result, oncogenes that induce hormone-independent proliferation invariably impair the expression of the thyroid-specific differentiation markers. Given that thyrotropin and insulin stimulate Akt activation in thyroid cells, we set out to determine the effects of Akt on thyroid cell proliferation, survival, and differentiation. To this end, we expressed constitutively active myristylated Akt (myrAkt) in PC Cl 3 thyroid cells. The myrAkt-expressing cells continued to proliferate, even in the absence of hormones, and they were resistant to programmed cell death induced by starvation. These effects were paralleled by the induction of the G1 cyclins D3 and E and by the inhibition of induction of the proapoptotic Fas, Fas ligand, and BAD genes in starved cells. However, in marked contrast with several other oncogenes, myrAkt did not interfere with the expression of thyroid differentiation functions. These results unveil the existence of an Akt-triggered thyroid cell pathway that modulates proliferation and survival without affecting the expression of the thyroid cell differentiated phenotype.


Subject(s)
Protein Serine-Threonine Kinases , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins/physiology , Thyroid Gland/cytology , Animals , Apoptosis/genetics , Carrier Proteins/metabolism , Cell Division/genetics , Cell Line , Cell Survival/genetics , Cell Transformation, Neoplastic , Cyclin D3 , Cyclins/metabolism , DNA Fragmentation , DNA, Complementary/metabolism , Fas Ligand Protein , In Situ Nick-End Labeling , Membrane Glycoproteins/metabolism , Phenotype , Plasmids , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins c-akt , Rats , Rats, Inbred F344 , Signal Transduction , Transfection , bcl-Associated Death Protein , fas Receptor/metabolism
17.
Eur J Endocrinol ; 142(3): 286-93, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10700724

ABSTRACT

OBJECTIVE: The aim of this study was to investigate: (i) whether a persistent increase of cAMP interferes with the proliferation of transformed thyroid cells, and (ii) whether the degree of malignancy is correlated with the sensitivity to a transient and/or sustained increase in intracellular cAMP levels. DESIGN AND METHODS: To address these questions we used thyroid cell lines transformed with E1A oncogene from adenoviruses 5 (PC E1A cell line) or 2 (PC HE4 cell line), or infected with the polyoma murine leukemia virus (PC PyMLV cell line) carrying the middle T gene of the polyoma virus, or, finally, expressing both E1A and PyMLV. These cell lines present various degrees of malignancy: PC EIA and PC HE4 cells are not tumorigenic; PC PyMLV cells induce non-invasive tumors after a long latency period; and PC EIA+PyMLV cells are highly tumorigenic. RESULTS AND CONCLUSIONS: Thyroid cell proliferation required the transient increase of intracellular cAMP levels, while persistent elevation of cAMP blocked the proliferation of normal thyroid PC Cl 3 cells and of PC Cl 3 cells transformed by a variety of different oncogenes. In addition, sustained levels of cAMP induced apoptosis in cells carrying the adenovirus EIA oncogene, but not in cells transformed with other oncogenes or in the wild-type PC Cl 3 cells. Furthermore, middle T gene of the polyoma virus seemed to afford protection only from apoptosis induced by cAMP when middle T is present in thyroid cells along with the E1A gene.


Subject(s)
Adenovirus E1A Proteins/genetics , Cell Transformation, Neoplastic , Cyclic AMP/physiology , Thyroid Gland/metabolism , Animals , Apoptosis , Cell Division , Cell Line , Cell Transformation, Neoplastic/genetics , Cell Transformation, Viral , Cyclic AMP/metabolism , Cyclic AMP-Dependent Protein Kinases/metabolism , DNA Fragmentation , Leukemia Virus, Murine/genetics , Oncogenes , Polyomavirus/genetics , Rats , Thyroid Gland/cytology , Thyrotropin/physiology
18.
Hum Mol Genet ; 8(11): 1989-99, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10484767

ABSTRACT

The RET gene codes for a transmembrane tyrosine kinase which is a subunit of a multimeric complex that acts as a receptor for four structurally related molecules: the glial cell line-derived neurotrophic factor (GDNF), neurturin, artemin and persephin. Germline mutations of RET cause a dominantly inherited dysgenesis of the enteric nervous system known as Hirschsprung's disease (HSCR; aganglionosis megacolon). The majority of HSCR mutations results either in a reduction of dosage of the RET protein or in the loss of RET function. Two novel distinct mutations of RET that led either to the deletion of codon 1059 (denoted Delta1059) or to the substitution of a Pro for Leu1061 have been identified in five HSCR families. In one large pedigree, two children born from asymptomatic consanguineous parents presented a severe form of HSCR and were found to carry the mutation at codon 1061 in the homozygous state. A tyrosine residue at position 1062 is an intracytoplasmic docking site that enables RET to recruit several signalling molecules, including the Shc adaptor protein. We now report that both HSCR mutations impair the fixation of Shc to RET and consequently prevent its phosphorylation. In addition, quantitative analysis in PC12 cells reveals that mutation Delta1059 inactivates the ability of RET to transduce a downstream signal whereas mutation L1061P only partially inhibits the signalling of RET. Finally, we provide evidence that these effects are partly mediated via the disruption of the RET/Shc interaction. Collectively, these results demonstrate that HSCR can be ascribed to mutations of RET which interfere with the binding of transduction effectors, such as Shc, and further provide a biochemical explanation for the phenotype of patients carrying a homozygous mutation at codon 1061. Finally, these data indicate that Y1062 is a multifunctional docking site that confers to RET the capacity to engage downstream signalling pathways which exert a crucial role during enteric neurogenesis.


Subject(s)
Adaptor Proteins, Signal Transducing , Adaptor Proteins, Vesicular Transport , Codon/genetics , Drosophila Proteins , Hirschsprung Disease/genetics , Point Mutation , Proto-Oncogene Proteins/genetics , Receptor Protein-Tyrosine Kinases/genetics , Sequence Deletion , Signal Transduction/genetics , 3T3 Cells , Amino Acid Substitution , Animals , Binding Sites/genetics , Consanguinity , DNA Mutational Analysis , Female , Glial Cell Line-Derived Neurotrophic Factor Receptors , Humans , Infant, Newborn , Macromolecular Substances , Male , Mice , PC12 Cells , Pedigree , Phosphorylation , Proteins/metabolism , Proto-Oncogene Proteins c-ret , Rats , Recombinant Fusion Proteins/metabolism , Shc Signaling Adaptor Proteins , Src Homology 2 Domain-Containing, Transforming Protein 1 , Transfection
19.
Biochimie ; 81(4): 397-402, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10401675

ABSTRACT

The RET gene encodes a tyrosine kinase receptor for neurotrophic molecules. RET is a conceptually valuable example of how different mutations of a single gene may cause different diseases. Gene rearrangements activate the oncogenic potential of RET in human thyroid papillary carcinomas. On the other side, different point mutations activate RET in familial multiple endocrine neoplasia syndromes. Finally, inactivating mutations of RET can be present in Hirschsprung's disease patients. The detailed knowledge of the specific RET mutations responsible for human tumors provides relevant tools for the clinical management of these diseases. Moreover, the recent discovery of the growth factors which in vivo stimulate its signaling may shed new light on the role played by RET in the development and differentiation of the central and peripheral nervous system.


Subject(s)
Carcinoma, Papillary/genetics , Drosophila Proteins , Multiple Endocrine Neoplasia Type 2a/genetics , Multiple Endocrine Neoplasia Type 2b/genetics , Mutation , Proto-Oncogene Proteins/genetics , Receptor Protein-Tyrosine Kinases/genetics , Thyroid Neoplasms/genetics , Humans , Proto-Oncogene Proteins c-ret
20.
J Intern Med ; 243(6): 505-8, 1998 Jun.
Article in English | MEDLINE | ID: mdl-9681850

ABSTRACT

Cancer is a genetic disease caused by 'gain of function' mutations of oncogenes and 'loss of function' mutations of tumour suppressors and of genes involved in DNA repair mechanisms. The RET gene encodes a tyrosine kinase receptor for molecules belonging to the glial cell line-derived neurotrophic factor (GDNF) family. RET is a paradigmatic example of how different mutations of a single gene can lead to different neoplastic phenotypes. Indeed, gene rearrangements, often caused by chromosomal inversions, activate the oncogenic potential of RET in a fraction of human thyroid papillary carcinomas. On the other hand, different point mutations activate RET in familial multiple endocrine neoplasia syndromes familial medullary thyroid carcinoma (FMTC), MEN-2A and MEN-2B. Little information is so far available on the biochemical mechanisms by which the potent transforming and mitogenic signals of RET are delivered to the nucleus. However, recent data indicate coupling to the Shc-Ras-MAPK pathway as a necessary step in RET signal transduction.


Subject(s)
Drosophila Proteins , Multiple Endocrine Neoplasia Type 2a/genetics , Mutation , Proto-Oncogene Proteins/genetics , Receptor Protein-Tyrosine Kinases/genetics , Carcinoma, Papillary/genetics , Glial Cell Line-Derived Neurotrophic Factor Receptors , Humans , Multiple Endocrine Neoplasia Type 2a/enzymology , Protein-Tyrosine Kinases/genetics , Proto-Oncogene Proteins c-ret , Signal Transduction , Thyroid Neoplasms/genetics
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