cyclin-d1 and Neuroendocrine-Tumors

Human neuroendocrine tumors exhibit unique biological properties, and defining the molecular genetic alterations that underlie these distinctive features remains an important challenge. In addition to the MEN1 tumor suppressor gene, the cyclin D1 oncogene has demonstrated a role in the pathogenesis of parathyroid and gastroenteropancreatic neuroendocrine tumors. Up-regulation of cyclin D1 is observed early in tumor formation, implying a possible role in tumor initiation. Overexpression of cyclin D1 in the parathyroid glands of mice resulted in the tandem regulation of cellular proliferation and hormonal secretion, a feature intrinsic to neuroendocrine tumors.

Topics: Cyclin D1; Gastrointestinal Neoplasms; Humans; Neuroendocrine Tumors; Pancreatic Neoplasms; Parathyroid Neoplasms

About 8384 cases of solid pseudopapillary neoplasms (SPN) of pancreas have been published in English literature, from 1933 to 2018. This is a low-grade tumor that usually occurs in children but is rare in adults and, in exceptional cases, can show extrapancreatic localization. In this paper we present 2 unusual cases of SPNs, 1 with retroperitoneal location (case 1) and 1 that was firstly diagnosed as a G1 neuroendocrine tumor (NET) and showed hepatic metastases after 13 years (case 2).. No symptoms in first case. The tumor was incidentally diagnosed, during ultrasound examination. In the second case, the metastasis was observed during regular follow-up.. The diagnosis was established based on the histological features and immunohistochemical profile that showed positivity for vimentin, nuclear β-catenin, cyclin D1, CD10, and SRY-related high-mobility group box 11 and negativity for maspin.. Surgical excision, in both cases.. No recurrences in first case, at 5 months after diagnosis. Hepatic metastases in the second case, at 13 years after diagnosis, with portal invasion after another 15 months.. Without a complex immunoprofile, SPN can be misdiagnosed as NET. SPN can be a low-grade tumor but long-time follow-up is mandatory to detect delayed metastases. A correct diagnosis is necessary for a proper therapeutic management.

Topics: Adenocarcinoma, Papillary; Adult; beta Catenin; Biomarkers, Tumor; Cyclin D1; Diagnosis, Differential; Female; Humans; Immunohistochemistry; Middle Aged; Neoplasms, Cystic, Mucinous, and Serous; Neprilysin; Neuroendocrine Tumors; Pancreas; Pancreatectomy; Pancreatic Neoplasms; Prognosis; Treatment Outcome; Vimentin

Conventional classifications of gastroenteropancreatic neuroendocrine tumours (GEP- NETs) are rather unsatisfactory because of the variation in survival within each subgroup. Molecular markers are being found able to predict patient outcome in more and more tumours. The aim of this study was to characterize the expression of the proteins cyclin D1, cyclin E and P53 in GEP- NETs and assess any prognostic impact. Tumor specimens from 68 patients with a complete follow-up were studied immunohistochemically for cyclin D1, cyclin E and P53 expression. High cyclin D1 and cyclin E immunostaining (≥ 5% positive nuclei) was found in 48 (71%) and 24 (35%) cases, and high P53 staining (≥ 10% positive nuclei) in 33 (49%) . High expression of P53 was more common in gastric neuroendocrine tumors and related to malignant behavior, being associate with a worse prognosis on univariate analysis (RR=1.9, 95%CI=1.1-3.2). High expression of cyclin E was significantly associated with shorter survival in the univariate analysis (RR=2.0, 95%CI=1.2-3.6) and multivariate analysis (RR=2.1, 95%CI=1.1-4.0). We found no significant correlation between the expression of cyclin D1 and any clinicopathological variables. Our study indicated a prognostic relevance for cyclin E and P53 immunoreactivity. Cyclin E may be an independent prognostic factor from the 2010 WHO Classification which should be evaluated in further studies.

Topics: Aged; Colorectal Neoplasms; Cyclin D1; Cyclin E; Female; Humans; Kaplan-Meier Estimate; Male; Middle Aged; Multivariate Analysis; Neuroendocrine Tumors; Pancreatic Neoplasms; Proportional Hazards Models; Retrospective Studies; Stomach Neoplasms; Tumor Suppressor Protein p53

Up-regulation of phosphatidylinositol-3-kinase (PI3K)-AKT signaling facilitates tumor cell growth and inhibits cell demise. The AKT-pathway also plays an important role in cytostatic therapy resistance and response to hypoxia and angiogenesis. Using real-time cell proliferation assay we examined the potency of triciribine in three distinct neuroendocrine gastrointestinal tumor cell lines. Also we investigated triciribine's induction of apoptosis and effects on a broad range of cancer-associated gene products. Furthermore, we characterized the role of PTEN as a possible predictor of sensitivity to triciribine in GEP-NETs. We also looked for additive anti-neoplastic effects of triciribine when combined with conventional cytostatic drugs or other targeted drugs, affecting different molecules of the PI3K-AKT-pathway and we assessed the potency of triciribine to inhibit tumor growth in vivo, by using the chick chorioallantoic membrane assay. Treatment of insulinoma (CM) or gut neuroendocrine tumor cells (STC-1) with triciribine significantly reduced tumor cell growth by 59% and 65%, respectively. By contrast, the highly expressing PTEN carcinoid cell line BON did not respond, even at higher doses. Combinations of triciribine with classic cytostatic drugs as well as drugs targeting other molecules of the PI3K-AKT-pathway led to synergistic anti-proliferative effects. Additional in vivo-evaluations confirmed the anti-neoplastic potency of triciribine. Thus, our data show that inhibition the AKT-pathway potently reduces the growth of GEP-NET cells alone or in combination therapies. AKT inhibition may provide a rationale for future evaluations.

Topics: Aging; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cyclin D1; Gastrointestinal Neoplasms; Gene Expression Regulation, Neoplastic; Humans; Insulinoma; Neuroendocrine Tumors; Pancreatic Neoplasms; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Ribonucleosides; Signal Transduction

In mice, genetic changes that inactivate the retinoblastoma tumor suppressor pathway often result in pancreatic neuroendocrine tumors (Pan-NETs). Conversely, in humans with this disease, mutations in genes of the retinoblastoma pathway have rarely been detected, even in genome-wide sequencing studies. In this study, we took a closer look at the role of the retinoblastoma pathway in human Pan-NETs.. Pan-NET tumors from 92 patients were subjected to immunohistochemical staining for markers of the retinoblastoma pathway. To search for amplifications of retinoblastoma pathway genes, genomic DNAs from 26 tumors were subjected to copy number analysis. Finally, a small-molecule activator of the retinoblastoma pathway was tested for effects on the growth of two Pan-NET cell lines.. A majority of tumors expressed high amounts of Cdk4 or its partner protein cyclin D1. High amounts of phosphorylated Rb1 were present in tumors that expressed high levels of Cdk4 or cyclin D1. The copy numbers of Cdk4 or the analogous kinase gene Cdk6 were increased in 19% of the tumors. Growth of the human Pan-NET cell line QGP1 was inhibited in a xenograft mouse model by the Cdk4/6 inhibitor, PD 0332991, which reactivates the retinoblastoma pathway.. Inactivation of the retinoblastoma pathway was indicated for most Pan-NETs. Gene amplification and overexpression of Cdk4 and Cdk6 suggests that patients with Pan-NETs may respond strongly to Cdk4/6 inhibitors that are entering clinical trials.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Animals; Cell Proliferation; Cyclin D1; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinase 6; Cyclin-Dependent Kinases; DNA Copy Number Variations; Female; Gene Expression Regulation, Neoplastic; Genes, Tumor Suppressor; Humans; Kaplan-Meier Estimate; Male; Metabolic Networks and Pathways; Mice; Middle Aged; Mutation; Neoplasm Staging; Neuroendocrine Tumors; Pancreatic Neoplasms; Piperazines; Pyridines; Retinoblastoma Protein; Transplantation, Heterologous

A series of 76 cases of gastrointestinal tract endocrine tumors, including 21 poorly differentiated endocrine carcinomas (PDECs, small cell carcinomas) and 55 well-differentiated endocrine neoplasms (WDENs, carcinoids), 18 metastatic and 37 nonmetastatic rectal carcinoids, were examined by immunohistochemical analysis for p16INK4a, cyclin D1, and retinoblastoma protein (pRB) expression. Overexpression of p16INK4a was noted in 16 (76%) of the PDECs and none of the WDENs (P < .0001). Loss of pRB expression was demonstrated in 14 (67%) of the PDECs and 17 (31%) of the WDENs (P = .004). Overexpression of cyclin D1 was noted in 49 (89%) of the WDENs and 3 (14%) of the PDECs (P < .0001). Loss of pRB expression was noted in 11 (61%) of 18 metastatic WDENs and only 6 (16%) of 37 nonmetastatic WDENs (P = .001). The p16INK4a/cyclin D1/pRB pathway was altered in gastrointestinal tract endocrine tumors, and the loss of expression of pRB may be helpful in identifying patients at high risk of metastasis in rectal WDENs.

Topics: Adult; Aged; Aged, 80 and over; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p16; Female; Gastrointestinal Neoplasms; Gene Expression; Humans; Immunohistochemistry; Male; Middle Aged; Neuroendocrine Tumors; Retinoblastoma Protein

Treatment options of advanced neuroendocrine tumors (NETs) are unsatisfactory. Hence, innovative therapeutic approaches are urgently needed. Inhibition of histone deacetylases (HDACs) is a promising new approach in cancer therapy. While several HDAC inhibitors have already entered clinical trials, the effect of HDAC inhibition on NET has not been investigated. Therefore, we evaluated the antineoplastic effects of three different HDAC inhibitors, trichostatin A (TSA), sodium butyrate (NaB), and MS-275, on growth and apoptosis of the gastrointestinal NET cell lines CM and BON. We could demonstrate that HDAC inhibition dose-dependently inhibited proliferation of both cell lines with IC50 values varying from the millimolar (NaB) to the micromolar (MS-275) and the nanomolar range (TSA). Moreover, HDAC inhibition potently induced apoptosis, which was accompanied by DNA-fragmentation, an up to 12-fold caspase-3 activation and downregulated Bcl-2 expression. Furthermore, HDAC inhibition resulted in cell cycle arrest at the G1-S-transition, which was associated with the suppression of cyclin D1 expression and induction of p21 and p27 expression. For BON cells, we observed an additional block in the G2/M phase, which was aligned with a downregulation of cyclin B1. In addition, combined treatment with MS-275 and somatostatin or the synthetic somatostatin analog octreotide was evaluated. Neither somatostatin nor its stable analog octreotide augmented the antiproliferative effect of MS-275 in NET cells. To conclude, our data show that HDAC inhibition is a promising new approach in the treatment of NET disease, which should be evaluated in clinical studies.

Topics: Antineoplastic Agents, Hormonal; Apoptosis; Benzamides; Butyrates; Carcinoid Tumor; Caspases; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cyclin B; Cyclin B1; Cyclin D1; Enzyme Inhibitors; Gastrointestinal Neoplasms; Histone Deacetylase Inhibitors; Histones; Hormones; Humans; Hydroxamic Acids; Neuroendocrine Tumors; Octreotide; Pyridines; Somatostatin

Constitutive expression of cyclin D1 is a frequent abnormality in human cancer and sustains the transformed phenotype. We have previously demonstrated that cyclin D1 is constitutively expressed in human BON neuroendocrine tumour cells due to an autocrine insulin-like growth factor-I (IGF-I) loop. Here we examine the regulation of cyclin D1 expression by endogenously released IGF-I in BON cells. Cyclin D1 expression in these cells was found to be dependent on phosphatidylinositol 3-kinase (PI3-K), but independent of the extracellular signal-regulated kinase cascade. Ras- and Rac-GTPases were found to be upstream activators of cyclin D1 expression, whereas protein kinase B/AKT and nuclear factor kappa B (NFkappaB) could be established as downstream mediators of cyclin D1 transcription in response to endogenously released IGF-I in these cells. In addition, the Ras/PI3-K/AKT/Rac/NFkappaB/cyclin D1 signaling cascade triggered by endogenously released IGF-I is sufficient to sustain Rb phosphorylation and cdk4 kinase activity in BON cells. In conclusion, our data provide the first comprehensive map of the signaling events elicited by endogenously released IGF-I leading to constitutive cyclin D1 expression in human neuroendocrine tumour cells.

Topics: Autocrine Communication; Cell Line, Tumor; Chromones; Cyclin D1; Gene Expression Regulation, Neoplastic; Humans; Insulin-Like Growth Factor I; Morpholines; Neuroendocrine Tumors; NF-kappa B; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; rac GTP-Binding Proteins; ras GTPase-Activating Proteins; Retinoblastoma Protein; RNA, Messenger

A total of 111 pulmonary neuroendocrine tumors comprising 13 typical carcinoids, five atypical carcinoids, 44 large-cell neuroendocrine carcinomas and 49 small-cell carcinomas were immunohistochemically studied for dysregulated cyclin B1 expression and disruption of the Rb/p16/cyclin D1 pathway (Rb pathway), and the results were correlated with tumor proliferation activity and clinical outcome. Overexpression of cyclins B1 and D1, respectively, was detected in no and 15% typical carcinoids, 20 and 20% atypical carcinoids, 84 and 32% large-cell neuroendocrine carcinomas, 84 and 10% small-cell carcinomas. Loss of Rb and p16 expression, respectively, was observed in no and 14% typical carcinoids, no and 40% atypical carcinoids, 49 and 18% large-cell neuroendocrine carcinomas, 84 and 8% small-cell carcinomas. In summary, 29% typical carcinoids, 20% atypical carcinoids, 78% large-cell neuroendocrine carcinomas and 93% small-cell carcinomas had Rb pathway aberrations. Rb pathway aberration was mostly attributed to Rb loss in small-cell carcinomas, while p16 loss and/or cyclin D1 overexpression besides Rb loss also played an important role in large-cell neuroendocrine carcinomas, while cyclin D1 overexpression was the only cause of Rb pathway aberration in carcinoid tumors. Thus, both cyclin B1-associated G2/M arrest and Rb-mediated G1 arrest are consistently compromised in high-grade large-cell neuroendocrine carcinoma and small-cell carcinoma, but are generally intact or occasionally altered in carcinoid tumor; the mechanisms involved in Rb pathway aberration among the tumor categories are different, reflecting a genetic divergence among the individual tumor categories. Cyclin B1 expression closely correlated with the Ki-67 labeling index either in the individual tumor categories or overall tumors (P < 0.0001, r = 0.742), suggesting that cyclin B1 is one of the key factors regulating cell proliferation in pulmonary neuroendocrine tumors. Neither cyclins B1 and D1, Rb, p16, nor Ki-67 correlated with patient survival in individual tumor categories, suggesting that the prognostic significance of these factors is tumor-type specific.

Topics: Biomarkers, Tumor; Carcinoid Tumor; Carcinoma, Large Cell; Carcinoma, Small Cell; Cyclin B; Cyclin B1; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p16; Humans; Immunohistochemistry; Ki-67 Antigen; Lung Neoplasms; Neuroendocrine Tumors; Retinoblastoma Protein; Signal Transduction; Survival Analysis

Rb protein in its hypophosphorylated form acts as a cell cycle regulator for G1 arrest. Both cyclin D1 overexpression and P16(INK4) loss of protein produce persistent hyperphosphorylation of Rb with resultant evasion of cell cycle arrest. To better establish the mechanisms of loss of Rb function in neuroendocrine lung tumors, we performed an immunohistochemical analysis of the P16(INK4)/cyclin D1/Rb pathway in the spectrum of neuroendocrine tumors, including 34 typical carcinoids (TCs), 25 atypical carcinoids (ACs), 42 large cell neuroendocrine carcinomas (LCNECs), and 79 small cell lung carcinomas (SCLCs). Absence of Rb expression was not observed in TCs but was seen in 21% of ACs, 68% of LCNECs, and 87% of SCLCs. P16 was expressed in 91% of TCs, 77% of ACs, 78% of LCNECs, and 93% of SCLCs. Cyclin D1 was overexpressed in 6% of TCs, 20% of ACs, 9.5% of LCNECs, and 1.3% of SCLCs. There was an inverse relationship between Rb and P16 in high-grade tumors (P < 0.001) and a direct relationship between cyclin D1 and Rb (P < 0.001) in all tumors, demonstrating that P16 and cyclin D1 act exclusively on the Rb pathway for cell cycle regulation. Overall, the Rb pathway (Rb/P16(INK4)/cyclin D1) was altered more frequently in ACs than in TCs (P = 0.001) and more frequently in LCNECs than in ACs (P = 0.001). Although Rb-negative tumors had shorter survival in the overall group (P < 0.001) as a result of lack of Rb in most SCLCs, cyclin D1 overexpression and P16 loss did not influence survival in any individual category. We conclude that Rb pathway of G1 arrest is consistently compromised in high-grade neuroendocrine lung tumors (92%), primarily through loss of Rb protein, and is intact in low-grade TCs. In ACs an intermediate level of alterations (59%) is seen, consistent with their less-aggressive behavior compared with high-grade tumors. The specific profile of the Rb pathway parameters might provide specific therapeutic targets in neuroendocrine lung tumors.

Topics: Adult; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p16; Female; G1 Phase; Humans; Immunohistochemistry; Lung Neoplasms; Male; Middle Aged; Neuroendocrine Tumors; Prognosis; Retinoblastoma Protein; Survival Rate

Carcinoid tumors are predominantly found in the gastrointestinal tract and are characterized by hypersecretion of various substances, including bioamines and neuropeptides, leading to functional tumor disease. Here, we demonstrate that human BON carcinoid tumor cells express functionally active insulin-like growth factor-I (IGF-I) receptors and secrete IGF-I, suggesting an autocrine action of this growth factor. The IGF-I receptor was functionally active. IGF-I stimulated phosphatidylinositol 3-kinase (PI3-kinase), p70 S6 kinase (p70s6k), and extracellular signal-regulated kinase 2 activity in BON cells. Furthermore, immunoneutralization of endogenously released IGF-I markedly reduced the high basal activity of p70s6k and extracellular signal-regulated kinase 2 in serum-starved BON cells. Exogenously added IGF-I induced a marked increase in chromogranin A secretion, a marker protein for neuroendocrine secretion, by a process that was largely dependent on PI3-kinase activity. In addition, immunoneutralization of endogenously released IGF-I markedly reduced basal chromogranin A release by BON cells. Thus, the autocrine IGF-I loop regulates basal neuroendocrine secretion in BON cells. Next, we investigated the role of IGF-I as a growth promoting agent for BON cells. Our data demonstrate that IGF-I stimulates anchorage-dependent and anchorage-independent growth of BON cells by a pathway that involves PI3-kinase, mammalian target of rapamycin/p70s6k, and mitogen-activated protein kinase kinase 1 activity. Interestingly, mitogen-activated protein kinase kinase 1 activity was less important for anchorage-independent growth of BON cells. Endogenously released IGF-I was found to be largely responsible for autonomous growth of BON cells in serum-free medium and for the constitutive expression of cyclin D1 in these cells. In conclusion, IGF-I is a major autocrine regulator of neuroendocrine secretion and growth of human BON neuroendocrine tumor cells. Because our data also demonstrate that a significant proportion of neuroendocrine tumors express the IGF-I receptor and its ligand, interference with this pathway could be useful in the treatment of hypersecretion syndromes and growth of human neuroendocrine tumors.

Topics: Carcinoid Tumor; Cell Adhesion; Cell Division; Chromogranin A; Chromogranins; Cyclin D1; Enzyme Activation; Humans; Insulin-Like Growth Factor Binding Protein 2; Insulin-Like Growth Factor I; MAP Kinase Kinase 1; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase Kinases; Neuroendocrine Tumors; Phosphatidylinositol 3-Kinases; Protein Serine-Threonine Kinases; Receptor, IGF Type 1; Ribosomal Protein S6 Kinases; Tumor Cells, Cultured