Dataset Information

Cyclic AMP inhibits the proliferation of thyroid carcinoma cell lines through regulation of CDK4 phosphorylation.

ABSTRACT: How cyclic AMP (cAMP) could positively or negatively regulate G1 phase progression in different cell types or in cancer cells versus normal differentiated counterparts has remained an intriguing question for decades. At variance with the cAMP-dependent mitogenesis of normal thyroid epithelial cells, we show here that cAMP and cAMP-dependent protein kinase activation inhibit S-phase entry in four thyroid carcinoma cell lines that harbor a permanent activation of the Raf/ERK pathway by different oncogenes. Only in Ret/PTC1-positive TPC-1 cells did cAMP markedly inhibit the Raf/ERK cascade, leading to mTOR pathway inhibition, repression of cyclin D1 and p21 and p27 accumulation. p27 knockdown did not prevent the DNA synthesis inhibition. In the other cells, cAMP little affected these signaling cascades and levels of cyclins D or CDK inhibitors. However, cAMP differentially inhibited the pRb-kinase activity and T172-phosphorylation of CDK4 complexed to cyclin D1 or cyclin D3, whereas CDK-activating kinase activity remained unaffected. At variance with current conceptions, our studies in thyroid carcinoma cell lines and previously in normal thyrocytes identify the activating phosphorylation of CDK4 as a common target of opposite cell cycle regulations by cAMP, irrespective of its impact on classical mitogenic signaling cascades and expression of CDK4 regulatory partners.

SUBMITTER: Rocha AS

PROVIDER: S-EPMC2575166 | biostudies-literature | 2008 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Cyclic AMP inhibits the proliferation of thyroid carcinoma cell lines through regulation of CDK4 phosphorylation.

Rocha Ana Sofia AS Paternot Sabine S Coulonval Katia K Dumont Jacques E JE Soares Paula P Roger Pierre P PP

Molecular biology of the cell 20080917 11

How cyclic AMP (cAMP) could positively or negatively regulate G1 phase progression in different cell types or in cancer cells versus normal differentiated counterparts has remained an intriguing question for decades. At variance with the cAMP-dependent mitogenesis of normal thyroid epithelial cells, we show here that cAMP and cAMP-dependent protein kinase activation inhibit S-phase entry in four thyroid carcinoma cell lines that harbor a permanent activation of the Raf/ERK pathway by different o ...[more]

PMID: 18799615

Similar Datasets

Project description:Background Lung cancer is one of the most common human malignant tumors and the leading cause of cancer death worldwide. Biphenyl hydrolase-like (BPHL) is a gene encoding the human BPHL enzyme, a serine hydrolase that catalyzes the hydrolytic activation of amino acid ester prodrugs of nucleoside analogs such as valacyclovir and valganciclovir. However, the role of BPHL in lung cancer is still unknown. Methods In this study, we assessed the effect BPHL knockdown on the proliferation, apoptosis, colony formation, metastasis, and cell cycle of cancer cells. BPHL knockdown NCI-H1299 and A549 cells demonstrated decreased proliferation, as measured by Celigo cell counting. The MTT assay results were consistent with Celigo cell counting. Caspase 3/7 activity increased significantly in the NCI-H1299 and A549 cells after shBPHL knockdown. Decreased colony formation in the NCI-H1299 and A54 cells after shBPHL knockdown, as measured by crystal violet staining. Transmigration assay using a Transwell demonstrated that there were significantly fewer migrating cells in the lower chamber in the BPHL knockdown NCI-H1299 and A549 cells. Cell cycle analysis by Propidium Iodide (PI) staining and fluorescence activated cell sorter (FACS). We also explored the effect of BPHL knockdown on tumor growth in a mouse model of tumor implantation in nude mice. Results We found that the knockdown of BPHL gene expression by short hairpin RNA (shRNA) leads to a decrease in proliferation, colony formation, and metastasis and an increase in apoptosis in two lung adenocarcinoma (LUAD) cell lines in vitro. BPHL knockdown induces decreased tumor growth, colony formation, and metastasis; increased apoptosis; and altered cell cycle destruction. BPHL knockdown results in decreased tumor growth in vivo. Moreover, BPHL knockdown A549 cells demonstrated slower growth compared to control cells upon implantation in nude mice, confirming the in vitro findings. Conclusions In this study, the data indicate that BPHL potentially promotes proliferation, inhibits apoptosis, and increases colony formation and metastasis in lung cancer. Overall, our study suggests that BPHL may be a gene that promotes tumor growth in lung cancer.

Project description:BackgroundCDK4/6 inhibitors (CDK4/6i) have been established as standard treatment against advanced Estrogen Receptor-positive breast cancers. These drugs are being tested against several cancers, including in combinations with other therapies. We identified the T172-phosphorylation of CDK4 as the step determining its activity, retinoblastoma protein (RB) inactivation, cell cycle commitment and sensitivity to CDK4/6i. Poorly differentiated (PDTC) and anaplastic (ATC) thyroid carcinomas, the latter considered one of the most lethal human malignancies, represent major clinical challenges. Several molecular evidence suggest that CDK4/6i could be considered for treating these advanced thyroid cancers.MethodsWe analyzed by two-dimensional gel electrophoresis the CDK4 modification profile and the presence of T172-phosphorylated CDK4 in a collection of 98 fresh-frozen tissues and in 21 cell lines. A sub-cohort of samples was characterized by RNA sequencing and immunohistochemistry. Sensitivity to CDK4/6i (palbociclib and abemaciclib) was assessed by BrdU incorporation/viability assays. Treatment of cell lines with CDK4/6i and combination with BRAF/MEK inhibitors (dabrafenib/trametinib) was comprehensively evaluated by western blot, characterization of immunoprecipitated CDK4 and CDK2 complexes and clonogenic assays.ResultsCDK4 phosphorylation was detected in all well-differentiated thyroid carcinomas (n=29), 19/20 PDTC, 16/23 ATC and 18/21 thyroid cancer cell lines, including 11 ATC-derived ones. Tumors and cell lines without phosphorylated CDK4 presented very high p16CDKN2A levels, which were associated with proliferative activity. Absence of CDK4 phosphorylation in cell lines was associated with CDK4/6i insensitivity. RB1 defects (the primary cause of intrinsic CDK4/6i resistance) were not found in 5/7 tumors without detectable phosphorylated CDK4. A previously developed 11-gene expression signature identified the likely unresponsive tumors, lacking CDK4 phosphorylation. In cell lines, palbociclib synergized with dabrafenib/trametinib by completely and permanently arresting proliferation. These combinations prevented resistance mechanisms induced by palbociclib, most notably Cyclin E1-CDK2 activation and a paradoxical stabilization of phosphorylated CDK4 complexes.ConclusionOur study supports further clinical evaluation of CDK4/6i and their combination with anti-BRAF/MEK therapies as a novel effective treatment against advanced thyroid tumors. Moreover, the complementary use of our 11 genes predictor with p16/KI67 evaluation could represent a prompt tool for recognizing the intrinsically CDK4/6i insensitive patients, who are potentially better candidates to immediate chemotherapy.

Dataset Information

Cyclic AMP inhibits the proliferation of thyroid carcinoma cell lines through regulation of CDK4 phosphorylation.

Publications

Cyclic AMP inhibits the proliferation of thyroid carcinoma cell lines through regulation of CDK4 phosphorylation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets