RESUMO
Somatic mutations in a subset of growth hormone (GH)-secreting pituitary tumors convert the gene for the alpha polypeptide chain (alpha s) of Gs into a putative oncogene, termed gsp. These mutations, which activate alpha s by inhibiting its guanosine triphosphatase (GTPase) activity, are found in codons for either of two amino acids, each of which is completely conserved in all known G protein alpha chains. The likelihood that similar mutations would activate other G proteins prompted a survey of human tumors for mutations that replace either of these two amino acids in other G protein alpha chain genes. The first gene so far tested, which encodes the alpha chain of Gi2, showed mutations that replaced arginine-179 with either cysteine or histidine in 3 of 11 tumors of the adrenal cortex and 3 of 10 endocrine tumors of the ovary. The mutant alpha i2 gene is a putative oncogene, referred to as gip2. In addition, gsp mutations were found in 18 of 42 GH-secreting pituitary tumors and in an autonomously functioning thyroid adenoma. These findings suggest that human tumors may harbor oncogenic mutations in various G protein alpha chain genes.
Assuntos
Doenças do Sistema Endócrino/genética , Proteínas de Ligação ao GTP/genética , Mutação , Neoplasias/genética , Oncogenes , Neoplasias Hipofisárias/genética , Sequência de Aminoácidos , Sequência de Bases , DNA de Neoplasias/genética , Feminino , GTP Fosfo-Hidrolases/genética , GTP Fosfo-Hidrolases/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Humanos , Masculino , Dados de Sequência Molecular , Sondas de Oligonucleotídeos , Reação em Cadeia da PolimeraseRESUMO
BACKGROUND: Most patients requiring bilateral adrenalectomy have adrenocorticotropin hormone (ACTH)-dependent Cushing's syndrome. Some of these patients are severely debilitated from the chronic effects of cortisol overproduction. This study aimed to analyze the indications, safety, efficacy, and outcomes for laparoscopic bilateral adrenalectomy from the authors' experience. METHODS: A retrospective review was conducted at a university tertiary referral center. Between March 1996 and August 2006, 30 consecutive patients underwent simultaneous laparoscopic bilateral adrenalectomy. The patient records were analyzed to obtain patient demographics, disease etiology, surgical approach, operating room information, postoperative complications (30 days), hospital length of stay (LOS), and follow-up information. RESULTS: The 30 participants (22 women and 8 men) had a mean age of 44 years. The indications for bilateral adrenalectomy were refractory Cushing's disease (n = 16), occult ectopic ACTH syndrome (n = 9), and bilateral pheochromocytoma (n = 5). A mean of 53 months elapsed between onset of symptoms and adrenalectomy. Laparoscopic bilateral adrenalectomy was completed for all the patients with no intraoperative complications. Four patients (13%) experienced six complications. The mean postoperative LOS was 3.5 days (range, 1-12 days). Seven patients required a preoperative LOS, for a mean of 7.1 days (range, 1-20 days), and a postoperative LOS, for a mean of 5 days (range, 2-12 days). The 23 patients who did not require preoperative hospitalization had a mean postoperative LOS of 3 days (range, 1-7 days). All the patients received postoperative steroid replacement and appropriate follow-up assessment with an endocrinologist. At this writing, the patients with Cushing's syndrome available for follow-up evaluation continue to receive steroid replacement, and all the pheochromocytoma patients have experienced a documented postoperative biochemical cure. CONCLUSIONS: Laparoscopic bilateral adrenalectomy is safe and effective for this high-risk patient population. Although patients should be monitored closely in the postoperative period, most are discharged with glucocorticoid and mineralocorticoid replacement in a short time without complications.
Assuntos
Neoplasias das Glândulas Suprarrenais/cirurgia , Adrenalectomia/métodos , Laparoscopia/métodos , Adolescente , Neoplasias das Glândulas Suprarrenais/mortalidade , Neoplasias das Glândulas Suprarrenais/patologia , Adulto , Estudos de Coortes , Síndrome de Cushing/diagnóstico , Síndrome de Cushing/mortalidade , Síndrome de Cushing/cirurgia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Feocromocitoma/diagnóstico , Feocromocitoma/mortalidade , Feocromocitoma/cirurgia , Estudos Retrospectivos , Medição de Risco , Taxa de Sobrevida , Fatores de Tempo , Resultado do TratamentoRESUMO
Patients with mucinous colorectal cancers characteristically present with advanced disease, however, the relationship between mucin production by colon cancer cells and their metastatic potential remains unclear. We therefore sought to define the relationship between mucin production by human colon cancer cells and metastatic ability by employing animal models of colon cancer metastasis. LS LiM 6, a colon carcinoma cell line with high liver metastasizing ability during cecal growth in nude mice produced twofold more metabolically labeled intracellular mucin and secreted four- to fivefold more mucin into the culture medium compared to poorly metastatic parental line LS174T. This was accompanied by a similar elevation in poly(A)+ RNA detected by blot hybridization with a human intestinal mucin cDNA probe, and increases in mucin core carbohydrate antigens determined immunohistochemically. Variants of LS174T selected for high (HM 7) or low (LM 12) mucin synthesizing capacity also yielded metastases after cecal growth and colonized the liver after splenic-portal injection in proportion to their ability to produce mucin. Inhibition of mucin glycosylation by the arylglycoside benzyl-alpha-N-acetyl-galactosamine greatly reduced liver colonization after splenic-portal injection of the tumor cells. These data suggest that mucin production by human colon cancer cells correlates with their metastatic potential and affects their ability to colonize the liver in experimental model systems.
Assuntos
Carcinoma/metabolismo , Carcinoma/patologia , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Mucinas/biossíntese , Metástase Neoplásica , Animais , Northern Blotting , Glicosilação , Humanos , Técnicas Imunoenzimáticas , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/secundário , Camundongos , Camundongos Nus , Mucinas/genética , Transplante de Neoplasias , RNA Mensageiro/genética , Transplante HeterólogoRESUMO
Alterations in cell surface proteins and glycoproteins may play a key role in determining the metastatic behavior of tumor cells. The cell surface proteins of a series of related murine colon cancer cells selected in an animal model for colon cancer metastasis (R. S. Bresalier et al., Cancer Res., 47: 1398-1406, 1987) were therefore compared by a variety of biochemical methods. Lactoperoxidase-catalyzed iodination of cell surface proteins followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated quantitative and qualitative differences in the cell surface protein profiles of parental cell line 51B (low metastatic potential) and its metastatic derivatives 51B LiM 5 and 51B LiM 6. Labeling of sialic acid-containing proteins suggested that, in the case of at least four of these proteins (Mr 170,000, 120,000, 95,000, and 55,000), this represented an increase in radioactive labeling of sialoglycoproteins from the metastatic lines. Affinity chromatography of solubilized 125I-labeled cell membrane proteins revealed a 2- to 3-fold increase in wheat germ agglutinin and Sambucus nigra lectin binding associated with the metastatic lines, compared to the poorly metastatic parent. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of material eluted from these columns demonstrated enhancement of proteins from the metastatic cells corresponding in molecular weight to the previously identified major sialoglycoproteins. Neuraminidase-releasable membrane-associated sialic acid and sialyltransferase activities were 2- to 3-fold higher in the metastatic cell lines compared to the parental line. Liver colonization after intrasplenic injection of the various lines into syngeneic mice was dramatically reduced by prior removal of cell surface sialic acid. Immunohistochemical staining of primary and metastatic tumors formed after cecal injection of parental 51B suggested selective metastasis by wheat germ agglutinin-binding tumor cells. These results further support the concept that cell membrane sialylation is important in determining the metastatic potential of cancer cells.
Assuntos
Neoplasias do Colo/análise , Glicoproteínas de Membrana/análise , Proteínas de Neoplasias/análise , Sialoglicoproteínas/análise , Animais , Neoplasias do Colo/patologia , Eletroforese em Gel de Poliacrilamida , Neoplasias Hepáticas/secundário , Camundongos , Peso Molecular , Ácido N-Acetilneuramínico , Metástase Neoplásica , Ácidos Siálicos/farmacologia , Sialiltransferases/análise , Células Tumorais Cultivadas , Aglutininas do Germe de Trigo/metabolismo , beta-D-Galactosídeo alfa 2-6-SialiltransferaseRESUMO
Laminin, a major basement membrane-specific glycoprotein, promotes the attachment, migration, and invasion of a variety of tumor cells. Since laminin is present in the perisinusoidal matrix of the liver, we studied its effects on liver colonization by human colon cancer cells (HM7, LiM6) previously shown to have liver-metastasizing ability in athymic mice. These malignant cells expressed high levels of a 32-kDa laminin-binding protein on Western blot analysis when compared to the low metastatic parental cell line. Coinjection of laminin alpha chain-derived peptides which contain the amino acid sequence Ile-Lys-Val-Ala-Val (IKVAV) significantly stimulated liver colonization as determined by liver weight (P < 0.005) and number of tumor nodules (P < 0.02) 3 weeks after splenic-portal inoculation into nude mice. No stimulation was seen with a control peptide containing the same amino acids but in a scrambled sequence. In contrast, the Tyr-Ile-Gly-Ser-Arg peptide from the laminin beta 1 chain significantly inhibited HM7 liver colonization. These differences were not due to alterations in the number of cells initially reaching the liver as determined by injection of [125I]iododeoxyuridine-labeled tumor cells, but retention in the liver was stimulated by the IKVAV-containing peptides. Flow analysis indicated that the IKVAV peptide may act, in part, by stimulating homotypic adhesion of tumor cells. These data suggest that interactions of colon cancer cells with the IKVAV site on laminin may play a role in the formation of metastatic foci in the liver through cell-cell or cell-substratum interactions which promote metastasis.
Assuntos
Adenocarcinoma/patologia , Adenocarcinoma/secundário , Neoplasias do Colo/patologia , Laminina/farmacologia , Neoplasias Hepáticas/secundário , Fragmentos de Peptídeos/farmacologia , Sequência de Aminoácidos , Animais , Adesão Celular/efeitos dos fármacos , Humanos , Neoplasias Hepáticas/patologia , Camundongos , Camundongos Nus , Dados de Sequência Molecular , Invasividade Neoplásica , Receptores de Laminina/metabolismoRESUMO
Several recent articles question whether patients with asymptomatic hyperparathyroidism and minimal hypercalcemia should be treated by parathyroidectomy. We therefore reviewed our experience in 103 consecutive patients with primary hyperparathyroidism who were treated by parathyroidectomy to determine, first, how many of these patients had asymptomatic or symptomatic hyperparathyroidism, and second, did these patients benefit from parathyroidectomy? We also analyzed the safety of parathyroidectomy in 426 consecutive patients, including 79 who required reoperation for hyperparathyroidism, specifically looking for complications and the outcome of these procedures. Our study documents the following: (1) only 2 of 103 (2%) patients referred for parathyroidectomy had "true" asymptomatic hyperparathyroidism; (2) only symptoms of fatigue, bone pain, and weight loss correlated with the degree of hypercalcemia, whereas muscular weakness, psychiatric symptoms, nocturia, polyuria, recent memory loss, constipation, and nephrolithiasis did not; (3) only 1 of 15 patients who were referred as asymptomatic were truly asymptomatic after more thorough questioning, and all 14 improved following parathyroidectomy; (4) 81% of the patients who were referred with symptoms improved following parathyroidectomy; and (5) permanent complications occurred in only 4 patients. All but 1 had reoperations for persistent or recurrent hyperparathyroidism (3 vocal cord paralyses and 1 hypoparathyroidism requiring autotransplantation of cryopreserved parathyroid tissue). There was 1 death of an 84-year-old woman with hypercalcemic crisis. Thus, most patients with hyperparathyroidism are symptomatic and benefit symptomatically and metabolically from parathyroidectomy, which is a safe operation.
Assuntos
Hipercalcemia/etiologia , Hiperparatireoidismo/diagnóstico , Hiperparatireoidismo/cirurgia , Paratireoidectomia , Feminino , Humanos , Hiperparatireoidismo/epidemiologia , Hiperparatireoidismo/terapia , Complicações Pós-Operatórias , Fatores de Risco , Inquéritos e QuestionáriosRESUMO
The plasma concentration of immunoreactive PTH (iPTH) increases with postmaturational aging in both humans and animals. In the present study we determined the basal, maximally stimulated, and maximally suppressed levels of iPTH and the concentration of whole blood ionized calcium sufficient to produce half-maximal suppression of the plasma concentration of iPTH (set-point for PTH release) in male Fischer 344 rats aged 3, 6, 12, 18, 24, and 28 months. Basal iPTH increased 2.3-fold from 3 to 28 months of age, whereas basal blood ionized calcium remained unchanged. The set-point for PTH release increased steadily and significantly (P < 0.001) from 1.19 +/- 0.09 mM at 3 months to 1.37 +/- 0.13 mM at 24 months and then declined slightly to 1.32 +/- 0.11 mM at 28 months of age. Basal iPTH correlated significantly with set-point. Neither maximally stimulated nor maximally suppressed iPTH levels showed any significant change with advancing age. These results suggest that the age-related increase in basal plasma iPTH in the rat may be in part a consequence of an increase in the set-point for PTH release.
Assuntos
Envelhecimento/sangue , Hormônio Paratireóideo/sangue , Animais , Masculino , Ratos , Ratos Endogâmicos F344 , Análise de Regressão , Fatores de TempoRESUMO
Desensitization or decreased response to the same (homologous) or other stimuli (heterologous) is a well known process. Homologous desensitization to TSH has been demonstrated in normal thyroid tissue. Chinese hamster ovary cells (CHO) transfected with normal human TSH receptor (hTSHR) DNA, in contrast, have been reported not to desensitize. The purpose of our investigation was to determine whether CHO cells transfected with hTSHR desensitize in response to TSH and postreceptor stimulation. CHO cells were stably transfected with plasmid DNA containing hTSHR; nontransfected CHO cells served as the control. TSH (10 mU/ml), 5'-beta,gamma-imido-triphosphate [Gpp(NH)p; 0.1 mM], sodium fluoride (NaF; 10 mM), forskolin (10 microM), and (Bu)2cAMP (100 microM) were used to determine whether homologous or postreceptor heterologous desensitization of adenylate cyclase activity occurred in CHO-transfected cells. Intracellular cAMP accumulation was determined by RIA. Cells were incubated with TSH (to stimulate TSH receptor), Gpp(NH)p, NaF (to stimulate G-protein), forskolin (to stimulate adenylate cyclase activity), and (Bu)2cAMP (nonmetabolized cAMP analog). A second incubation was carried out with TSH (10 mU/ml). Maximal desensitization to either TSH or postreceptor stimulation was observed at 2 h. When transfected CHO cells were preexposed to TSH (10 mU/ml) for 4 h, even the smallest dose of TSH (0.001 mU/ml) caused desensitization. All substances that increased the intracellular cAMP concentration, such as TSH, Gpp(NH)p, NaF, forskolin, and (Bu)2cAMP, caused desensitization. The decrease in the cAMP response to TSH added in the second incubation was 63% less than the initial response to TSH or to postreceptor stimulation (P = 0.0001). In conclusion, desensitization of hTSHR-transfected CHO cells occurs in response to both receptor and postreceptor stimulation that increase cAMP levels. Because hTSHR transfected CHO cells desensitize, no specific thyroid factor(s) other than increased levels of cAMP is required.
Assuntos
Adenilil Ciclases/metabolismo , Receptores da Tireotropina/fisiologia , Animais , Células CHO , Cricetinae , Cricetulus , AMP Cíclico/fisiologia , Relação Dose-Resposta a Droga , Proteínas de Ligação ao GTP/fisiologia , Guanilil Imidodifosfato/farmacologia , Receptores da Tireotropina/genética , Tireotropina/farmacologia , TransfecçãoRESUMO
The prognosis of patients with follicular (FTC) and papillary (PTC) thyroid cancer depends on age and the size and extent of the tumor. Differentiated thyroid cancers bind more epidermal growth factor (EGF) than normal thyroid tissue, but the role of EGF in the proliferation and invasion of thyroid cancer is unknown. We investigated the effects of EGF on growth, migration, and invasion in a follicular thyroid cancer that metastasized to cervical lymph nodes and the lung (FTC 133, primary; FTC 236, lymph node; and FTC 238, lung metastasis) and in a papillary thyroid cancer (PTC-UC3). As measured by the formazan method (dimethylthiazol-diphenyltetrazolium bromide), EGF caused a dose- and time-dependent increase in the growth of FTC 133 and PTC-UC3 by 25%, but its stimulatory effect on growth of the metastatic FTC subclones was smaller (FTC 236, 14%; FTC 238, 8%; P < 0.001). EGF also enhanced the ability of all cell lines to migrate (through 8-microns pore membranes without Matrigel) or invade (membranes with Matrigel). Migration of FTC 133 was enhanced from 86% migrated tumor cells to 95% after 72 h (P < 0.02). Again, stimulation by EGF was lower in FTC 236 and FTC 238. EGF increased migration in PTC-UC3 from 49% to 58%. EGF stimulated invasion of FTC 133 from 17.5% to 24.9%. In the absence of EGF, FTC 238 was the most invasive tumor, but, again, the EGF stimulatory effect was less pronounced than in the primary tumor. EGF stimulated the invasion of PTC-UC3 from 10.9% to 14.3% (P < 0.03). EGF also stimulated the growth of thyroid cancer xenografts in nude mice. Although all FTC cell lines were 100% tumorigenic in nude mice, PTC-UC3 was less tumorigenic. However, after sc inoculation of EGF-pretreated tumor cells, 7 of 10 animals developed tumors (mean size, 2.3 cm3) compared to 2 of 10 animals (mean size, 1.4 cm3) in the control group (P < 0.02). In summary, EGF stimulates the growth and invasion of differentiated thyroid cancer cells in culture and in nude mice. Escape from growth factor control, such as in FTC 236 and FTC 238, may be an important step in the development of metastatic thyroid cancer.
Assuntos
Adenocarcinoma Folicular/patologia , Carcinoma Papilar/patologia , Divisão Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Fator de Crescimento Epidérmico/farmacologia , Neoplasias da Glândula Tireoide/patologia , Adenocarcinoma Folicular/secundário , Animais , Humanos , Neoplasias Pulmonares/secundário , Metástase Linfática , Camundongos , Camundongos Nus , Invasividade Neoplásica , Transplante de Neoplasias , Células Tumorais CultivadasRESUMO
Somatostatin and its analogs are antiproliferative in a wide range of normal and neoplastic tissues. In this study we investigated the effect of octreotide (SMS 201-995) on the invasion and growth of three follicular thyroid cancer (FTC) cell lines from one patient in vitro and in vivo. FTC133 was established from the primary tumor, FTC236 from a cervical lymph node metastasis, and FTC238 from a lung metastasis. Invasion was the ability of tumor cells to penetrate 8-microns pore polycarbonate membranes coated with Matrigel. Invasion and proliferation were analyzed using the MTT assay. For in vivo experiments, athymic nude mice were sc inoculated with 500,000 calls of FTC133. The animals were treated twice daily with octreotide sc (100-300 micrograms/kg). RIA studies yielded dose-dependent high plasma levels of octreotide (3.43-6.5 ng/mL). Octreotide had a biphasic effect, enhancing growth at low concentrations (1-10 nmol/mL) and inhibiting it at high concentrations (100 nmol to 1 mumol/mL). Octreotide had also a dose-dependent biphasic effect on the invasion of FTC, inhibiting the invasion of all follicular thyroid cancer lines at high concentrations. However, it affected invasion less than growth. Octreotide (10 nmol/mL) stimulated the invasion of FTC133 by 13%, whereas stimulation was lower in both FTC metastases (FTC236, 6%; FTC238, 7%; P < 0.01). At higher concentrations (100 nmol to 1 mumol/mL), octreotide inhibited invasion of FTC133 by 17% (FTC236, 15%; FTC238, 17%; P < 0.01). During a 3-week treatment period, octreotide had no antiproliferative effect on the growth of FTC133 cells in nude mice. In conclusion, octreotide at low concentrations stimulates and at high concentrations inhibits the growth and invasion of follicular thyroid cancer cells in culture. However, it has no effect on the growth of FTC cells in animal experiments. Thus, the value of octreotide as an antitumoral agent in follicular thyroid cancer must be critically questioned.
Assuntos
Antineoplásicos Hormonais/farmacologia , Divisão Celular/efeitos dos fármacos , Octreotida/farmacologia , Neoplasias da Glândula Tireoide/patologia , Animais , Antineoplásicos Hormonais/administração & dosagem , Antineoplásicos Hormonais/uso terapêutico , Humanos , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/secundário , Metástase Linfática/patologia , Camundongos , Camundongos Nus , Invasividade Neoplásica , Transplante de Neoplasias , Octreotida/administração & dosagem , Octreotida/uso terapêutico , Neoplasias da Glândula Tireoide/tratamento farmacológico , Células Tumorais CultivadasRESUMO
Prognosis of differentiated thyroid cancer is best in young women. It has been proposed that sex steroids protect premenopausal women from aggressive thyroid malignancies. Some thyroid tissues have estrogen receptors, and estrogen stimulates human thyroid cells. Tamoxifen is thought to exert its antiproliferative effects mainly by blocking estrogen stimulation. However, recently, mechanisms independent of estrogen interactions were found to be important for the favorable effect. We investigated the effect of tamoxifen on the growth, migration, and invasion in three follicular thyroid cancer cell lines (FTC133, primary; FTC236, lymph node; and FTC238, lung metastasis) from one patient and two papillary lines (PTC-UC1 and PTC-UC3). Growth was measured by dimethylthiazol-diphenyltetrazolium bromide assays, and migration was determined by the ability of cells to penetrate 8-microns pore membranes, which were covered by Matrigel for invasion assays. For in vivo experiments, we used xenografts of FTC133 in nude mice. Tamoxifen (1.5 mumol/L) inhibited the growth of all thyroid cancer cell lines (FTC133, 59%; FTC236, 42%; FTC238, 46%; P < 0.01). This effect was less pronounced in PTC-UC1 (25%) and PTC-UC3 (19%; P < 0.006) cell lines. Tamoxifen also inhibited migration and invasion of FTC more than PTC. Invasion of FTC133 was inhibited by 36% (P < 0.01), FTC236 by 30%, and FTC238 by 32%. Immunohistochemistry showed no estrogen receptors in any cell line. Also, estradiol had no significant effect on the growth, migration, or invasion of FTC or PTC. Tamoxifen treatment inhibited the growth of FTC133 xenografts in nude mice by 52% compared to that in placebo-treated controls (P < 0.002). In conclusion, tamoxifen inhibited the growth, migration, and invasion of differentiated thyroid cancer cells in vitro and in vivo. This was not reversed by estrogen. Tamoxifen acts independently of estrogen interactions and may be useful as an adjuvant treatment for some differentiated human thyroid malignancies.
Assuntos
Carcinoma Papilar, Variante Folicular/patologia , Tamoxifeno/farmacologia , Neoplasias da Glândula Tireoide/patologia , Animais , Divisão Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Feminino , Humanos , Camundongos , Camundongos Nus , Invasividade Neoplásica , Transplante de Neoplasias , Células Tumorais CultivadasRESUMO
Invasion and metastasis may be caused by the escape of tumor cells from the negative control of growth factors. We analyzed the effects of transforming growth factor-beta 1 (TGF beta 1) on growth, migration, invasion, and adhesion in three follicular thyroid cancer cell lines (FTC133, primary; FTC236, lymph node metastasis; FTC238, lung metastasis) from one patient and in a papillary line (PTC-UC3). Cell growth was measured by dimethylthiazol-diphenyltetrazolium bromide assays, and migration (basal or epidermal growth factor stimulated) was determined by the ability of cells to penetrate 8-microns pore membranes that were covered with Matrigel for invasion assays. Moreover, we studied tumor cell adhesion to collagen type IV, fibronectin, and laminin. TGF beta 1 inhibited growth in FTC (FTC133, by 31%; FTC236, 15%; FTC238, 17%; P < 0.008), but not in PTC. Migration was inhibited in all cell lines. TGF beta 1 inhibited epidermal growth factor-stimulated migration of FTC133 by 43% vs. 29% without epidermal growth factor (P < 0.03). TGF beta 1 also inhibited invasion (FTC133, 32%; FTC236, 18%; FTC238, 16%; PTC-UC3, 32%; P < 0.02). All cell lines adhered preferably to collagen type IV and fibronectin. TGF beta 1 enhanced adhesion. Again, these effects were less pronounced in the FTC metastases. In conclusion, TGF beta 1 inhibits the growth, migration, and invasion of thyroid cancer cells in vitro. It enhances adhesion to components of the extracellular matrix. Metastatic thyroid tumors may be less responsive to the negative regulation of TGF beta 1.
Assuntos
Adenocarcinoma Folicular/patologia , Carcinoma Papilar/patologia , Neoplasias da Glândula Tireoide/patologia , Fator de Crescimento Transformador beta/farmacologia , Adesão Celular , Divisão Celular , Movimento Celular , Fator de Crescimento Epidérmico/farmacologia , Humanos , Invasividade Neoplásica , Células Tumorais CultivadasRESUMO
There is increasing evidence that phenylacetate inhibits growth and modulates differentiation in a variety of tumors with effects on gene expression, and protein prenylation and glycosylation at concentrations that have been safely used in humans. We evaluated the antineoplastic effects of phenylacetate in five thyroid cancer cell lines of follicular cell origin in vitro. We found early growth inhibition occurred with phenylacetate treatment at a dose of 2.5-10 mmol/L. The growth inhibition was cytostatic with the thyroid carcinoma cells arrested in the G0-1 cell phase. When evaluating the effect of phenylacetate on the differentiated functions of thyroid carcinoma cells, phenylacetate exposure: 1) decreased the TSH (10 mU/mL) growth response; 2) increased radioactive iodine (125I) uptake in two out of five cell lines; and 3) inhibited thyroglobulin secretion. Phenylacetate also inhibited the secretion of vascular endothelial growth factor (a glycoprotein dependent on glycosylation for efficient cellular excretion) from the thyroid cancer cell lines. Our results support that phenylacetate has an antiproliferative effect in many cell types, but the differentiating effects were not uniform. Importantly, we have identified that phenylacetate inhibits the secretion of vascular endothelial growth factor, which possibly mediates the antiangiogenic effects observed in vivo. Because of the minimal toxicity associated with phenylacetate treatment in humans, at concentrations we show to have a significant antineoplastic effect in thyroid carcinoma cells, phenylacetate could be useful in patients with differentiated thyroid cancer who fail conventional therapy or as an adjuvant to radioactive iodine therapy in patients with aggressive tumors.
Assuntos
Antineoplásicos/farmacologia , Fatores de Crescimento Endotelial/metabolismo , Linfocinas/metabolismo , Fenilacetatos/farmacologia , Neoplasias da Glândula Tireoide/tratamento farmacológico , Diferenciação Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Humanos , Neoplasias da Glândula Tireoide/metabolismo , Neoplasias da Glândula Tireoide/patologia , Células Tumorais Cultivadas , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio VascularRESUMO
Vascular endothelial growth factor (VEGF) is an angiogenic factor, and its expression has been rarely demonstrated in thyroid tumors. We, therefore, investigated the expression of VEGF messenger RNA (mRNA) and production of VEGF protein in cell lines from human primary and metastatic follicular (FTC-133, FTC-236, and FTC-238), papillary (TPC-1), Hürthle cell (XTC-1), and medullary thyroid cancers (MTC-1.1 and MTC-2.2), and in human thyroid tissues (papillary, follicular, medullary, and Hürthle cell cancers, follicular adenomas, and Graves' thyroid tissue) by Northern blot, immunohistochemistry, and enzyme-linked immunosorbent assay (ELISA) studies. All thyroid cell lines expressed a 4.2-kilobase VEGF mRNA. The VEGF mRNA levels were higher in the thyroid cancer cell lines than in primary cultures of normal thyroid cells, and higher in thyroid cancers of follicular than those of parafollicular cell origin. The VEGF mRNA levels were similar in primary and metastatic thyroid tumors. Immunohistochemical staining and Northern blot analysis of the cell lines correlated positively, thus thyroid cancer cell lines stained more intensely than normal thyroid cells and follicular tumor cells more intensely than parafollicular tumor cells. Again, no difference was noted in VEGF staining between primary and metastatic thyroid tumors. Deparafinized sections of papillary, follicular, and Hürthle cell cancers also stained much stronger than those of medullary thyroid cancers, benign, or hyperplastic (Graves' disease) thyroid tissue. Thyroid cancer cell lines (XTC-1 > TPC-1 > FTC-133 > MTC-1.1) also secreted more VEGF protein as measured by ELISA than did normal thyroid cells. VEGF secretion of cell lines derived from primary and metastatic thyroid tumors were similar. VEGF mRNA is therefore expressed, and VEGF protein is secreted by normal, hyperplastic, and neoplastic thyroid tissues. The higher levels of VEGF expression in differentiated thyroid cancers of follicular cell origin suggests a role in oncogenesis.
Assuntos
Fatores de Crescimento Endotelial/genética , Expressão Gênica , Linfocinas/genética , Glândula Tireoide/metabolismo , Neoplasias da Glândula Tireoide/metabolismo , Adenocarcinoma/metabolismo , Adenocarcinoma Folicular/metabolismo , Northern Blotting , Carcinoma Medular/metabolismo , Carcinoma Papilar/metabolismo , Diferenciação Celular , Fatores de Crescimento Endotelial/metabolismo , Ensaio de Imunoadsorção Enzimática , Humanos , Imuno-Histoquímica , Linfocinas/metabolismo , Splicing de RNA , RNA Mensageiro/análise , RNA Mensageiro/metabolismo , Células Tumorais Cultivadas , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio VascularRESUMO
Mutations in the tumor suppressor gene p53 are the most-common mutations found in human cancers. In thyroid cancers, p53 mutations generally are found only in poorly differentiated and undifferentiated tumors and in cell lines. To determine the prevalence of p53 mutations in thyroid neoplasms and thyroid cell lines, we screened 58 thyroid tissues and 3 thyroid cell lines, p53 primers bracketing exons 4, 5/6, 7, and 8 were used to amplify genomic DNA using the PCR. Mutations were screened by denaturing gradient gel electrophoresis and confirmed by sequencing. The two papillary thyroid cancer cell lines and the follicular thyroid carcinoma cell line (positive control) had transitions (CGT->CAT) in exon 8, codon 273, resulting in the replacement of arginine with histidine. No normal thyroid tissues or primary tumors from which the cell lines were derived demonstrated exon 8 mutations, using this technique. p53 immunocytochemistry demonstrated a progression of p53 immunopositivity between synchronous and metachronous neoplasms, paralleling the neoplastic progression from a benign adenoma to primary carcinoma, regional, and distant metastasis and ultimately, the cell lines, where intense immunopositivity is noted. In addition, fluorescence in situ hybridization, using probes specific for the p53 locus, revealed the presence of 3 homologues of p53 in the follicular cell line and 2 homologues in the papillary and Hürthle cell lines. These results suggest that a point mutation present in a small number of original tumor cells and amplification of the mutant allele may be responsible for immortalizing well-differentiated thyroid cancer cells into cell lines.
Assuntos
DNA de Neoplasias/análise , Genes p53/genética , Imuno-Histoquímica , Mutação Puntual , Neoplasias da Glândula Tireoide/genética , Proteína Supressora de Tumor p53/análise , Adenocarcinoma Folicular/genética , Carcinoma Papilar/genética , Sondas de DNA , Humanos , Hibridização in Situ Fluorescente , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/genéticaRESUMO
The aggressiveness of follicular thyroid cancer (FTC) varies widely, and metastasis is the primary cause of death. Uncontrolled proliferation of cancer cells may be associated with loss of growth factor control. We investigated the effects of stimulating (epidermal growth factor [EGF]; thyreotropin [TSH] in low concentrations) and inhibiting growth factors (transforming growth factor beta 1 [TGF beta 1]; TSH in high concentrations) on invasion and growth of FTC cell lines from the thyroid tumor (FTC133) and from the lymph node (FTC236) and lung (FTC238) metastases of the same patient. Invasion-penetration through an 8 microns pore membrane, covered by Matrigel (basement membrane)-and growth were measured using the MTT-method. EGF (10 ng/ml) and TSH in low concentrations (1 mU/ml) stimulated invasion and growth of all FTC cell lines, but the amplitude of stimulation differed significantly. The parental cell line FTC133 was considerably more responsive to growth factor stimulation than the metastatic clones. Invasion of FTC133 was enhanced by 42% (EGF; p < 0.02) and 21% (TSH; p < 0.01), invasion of FTC236 by 8% (EGF; p < 0.02) and 8% (TSH; p < 0.01), and invasion of FTC238 by 9% (EGF; p < 0.02) and 8% (TSH; p < 0.01). Conversely, invasion and growth of FTC133 were significantly more inhibited by TGF beta 1 (10 ng/ml) and supraphysiologic concentrations of TSH (100 mU/ml) than the cell lines from the lymph node and lung metastases. At day 7, invasion of FTC133 was inhibited by 32% (TGF beta 1; p < 0.02) and 21% (TSH; p < 0.01), invasion of FTC236 by 18% (TGF beta 1; p < 0.02) and 11% (TSH; p < 0.01), and invasion of FTC238 by 16% (TGF beta 1; p < 0.02) and 12% (TSH; p < 0.01). Moreover, we analyzed growth factor independence in minimally supplemented or unsupplemented medium. Growth, but no invasion was evident when cells were cultured completely unsupplemented over 7 days. These results suggest that metastatic FTCs may have developed by escaping from the normal control of TSH and other growth factors.
Assuntos
Adenocarcinoma Folicular/patologia , Substâncias de Crescimento/metabolismo , Neoplasias da Glândula Tireoide/patologia , Divisão Celular/efeitos dos fármacos , Meios de Cultura , Fator de Crescimento Epidérmico/farmacologia , Humanos , Técnicas In Vitro , Invasividade Neoplásica , Metástase Neoplásica , Tireotropina/farmacologia , Fator de Crescimento Transformador beta/farmacologia , Células Tumorais CultivadasRESUMO
Local invasion and metastatic spread to distant sites are major causes of death in patients with malignant pheochromocytoma. Since appropriate in vivo models do not exist, little is known about the underlying mechanisms of tumor growth and invasion. We, therefore, developed an animal model of malignant pheochromocytoma and established organotropic metastatic variants of PC12 rat pheochromocytoma cells. PC12 cells were established as xenografts to BALB/c NCR-NU mice. Subsequent to development of tumors or metastases, primary cultures from local tumors, metastases to lymph nodes, lungs and liver were established. These were subcultured in vitro and reinjected for up to five successive in vivo/in vitro cycles. Xenografted PC12 cells grew tumors with a doubling time of 6.78 +/- 0.58 days during log phase of tumor growth, killing hosts within 5-12 weeks depending on the experimental conditions. Tumors reproducibly metastasized to lymph nodes and the lung. Spontaneous metastases to the liver were not observed, but were achieved by intrasplenic injection of parent PC12 cells. In vitro, the metastatic cell lines displayed striking differences in morphology, overall growth patterns and nutritional requirements as well as binding to purified extracellular matrix proteins compared to the parent cell line. In vivo, the metastatic variants showed marked enhancement of metastatic ability. This is the first report of PC12 rat pheochromocytoma cells to exhibit the malignant phenotype in vivo. We also established variant PC12 cell lines that preferentially metastasized to specific sites and that had acquired different in vitro behavior and ability to metastasize. This unique model system should be useful for further studies relating to the invasion and metastases of pheochromocytoma and may prove valuable for investigations of novel antineoplastic therapies in vitro and in vivo.
Assuntos
Feocromocitoma/patologia , Feocromocitoma/secundário , Transplante Heterólogo/métodos , Animais , Adesão Celular , Divisão Celular , Proteínas da Matriz Extracelular/fisiologia , Neoplasias Hepáticas Experimentais/patologia , Neoplasias Hepáticas Experimentais/secundário , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/secundário , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Transplante de Neoplasias , Células PC12 , Ratos , Neoplasias Retroperitoneais/patologia , Neoplasias Retroperitoneais/secundárioRESUMO
Primary hyperparathyroidism is a common disorder and one that can usually (approximately 95%) be successfully treated by parathyroidectomy. PTH assays have become quite accurate for confirming the diagnosis. In patients with malignancy-associated hypercalcemia, parathyroid-like protein levels are usually increased, and radioimmunoassays being developed to quantitate serum levels of this protein will make the diagnosis easier. Treatment for a parathyroid adenoma is removal of the tumor and identification of the normal parathyroid glands. Treatment for primary or secondary hyperplasia is usually subtotal parathyroidectomy. Recurrent hyperparathyroidism is uncommon, except in patients with familial hyperparathyroidism, MEN-1 parathyroid carcinoma, or renal failure and secondary hyperparathyroidism. Persistent hyperparathyroidism is more common and is usually due to surgeon inexperience, but it is also caused by ectopically situated parathyroid glands, multiple abnormal parathyroid glands, or supranumerary parathyroid glands. Preoperative localization studies using ultrasound, thallium-technetium scanning, MRI, or CT scanning are reliable in patients with solitary parathyroid adenomas, but often fail to detect all of the abnormal parathyroid tissue in patients with multiple abnormal parathyroid glands. Intraoperative use of urinary cyclic AMP assays and rapid PTH assays have recently been used experimentally during parathyroid explorations to determine whether all hyperfunctioning parathyroid tissue has been removed, but these methods are not yet reliable or fast enough to be generally accepted. Most patients with primary hyperparathyroidism who are successfully treated by parathyroidectomy experience psychological, clinical, and metabolic benefits.
Assuntos
Hiperparatireoidismo/cirurgia , Cálcio/sangue , Diagnóstico Diferencial , Diagnóstico por Imagem/métodos , Humanos , Hiperparatireoidismo/diagnóstico , Hiperparatireoidismo/etiologia , Masculino , Glândulas Paratireoides/cirurgia , Hormônio Paratireóideo/sangue , Neoplasias das Paratireoides/complicações , Neoplasias das Paratireoides/cirurgiaRESUMO
Signal transduction of a human follicular thyroid cancer cell line (FTC133) was investigated. The protein kinase C (PKC)-agonist TPA enhanced invasion by 15%, whereas its antagonists staurosporine, chelerythrine and calphostin C were inhibiting by up to 62%. TSH and EGF stimulated invasion of FTC133. Antagonism of PKC reversed TSH-mediated stimulation, whereas it had no effect on EGF-stimulation. Our data provide evidence for an essential role of PKC in signal transduction of invasive thyroid cancer.
Assuntos
Invasividade Neoplásica , Proteína Quinase C/metabolismo , Transdução de Sinais/fisiologia , Neoplasias da Glândula Tireoide/patologia , Benzofenantridinas/farmacologia , Linhagem Celular Tumoral , Inibidores Enzimáticos/farmacologia , Humanos , Naftalenos/farmacologia , Proteína Quinase C/efeitos dos fármacos , Estaurosporina/farmacologia , Acetato de Tetradecanoilforbol/farmacologia , Neoplasias da Glândula Tireoide/enzimologia , Tireotropina/farmacologiaRESUMO
Tamoxifen inhibits invasion and growth of estrogen-receptor negative follicular thyroid cancer (FTC) cells in vitro and in vivo. To study the mechanisms involved, we documented the effects of tamoxifen and staurosporine on three metastatic FTC-cell lines. TPA (10 ng/ml) enhanced invasion and growth of FTC by 15% (P < 0.02). Tamoxifen (1.5 micromol/l) inhibited invasion of FTC133 by 36% (FTC236 30%; FTC238 32%; P < 0.01). TPA reversed the tamoxifen-mediated inhibition of invasion by 35% in FTC133 and 30% in FTC238 (P < 0.02). Staurosporine (10 ng/ml) inhibited invasion and growth of all FTC. At 0.1-1 ng/ml it enhanced the inhibitory effects of tamoxifen, but did not further inhibit invasion or growth at higher concentrations. We conclude that the antiproliferative and antiinvasive effects of tamoxifen on follicular thyroid cancer cells are at least partly mediated by an inhibition of protein kinase C.