BACKGROUND: Id proteins are a family of helix-loop-helix proteins and are regarded to be negative regulators of cell differentiation. In general, Id-1 and Id-2 expressions are upregulated during tumor development and progression in a variety of neoplasms, and these expressions may be associated with aggressive tumor behavior. However, little is known about the roles of Id-1 and Id-2 in thyroid neoplasms. METHODS: The expressions of Id-1 and Id-2 were assessed immunohistochemically in 310 normal, hyperplastic, and neoplastic thyroid tissues using tissue microarrays. RESULTS: Normal thyroid tissues rarely expressed Id-1 or Id-2. Moreover, whilst Id-1 expression was more elevated in malignant thyroid tissue than in hyperplastic thyroid tissue, Id-2 expression was more variable. No significant differences were observed between histologic subtypes of thyroid carcinomas with respect to Id-1 or Id-2 expression. Follicular adenomas showed higher expressions of Id-1 and Id-2 than thyroid carcinomas. No significant association was found between clinicopathological parameters and Id-1 expression, though Id-2 expression was significantly reduced in metastatic, stage IV tumors. CONCLUSION: The expressions of Id-1 and Id-2 were elevated in hyperplastic and neoplastic thyroid tissues. However, neither appears suitable as a marker of malignancy or an aggressive phenotype, although Id-2 expression in advanced thyroid carcinomas may reflect a favorable prognosis.
Adenocarcinoma, Follicular ; Adenoma ; Carcinoma, Papillary ; Cell Differentiation ; Humans ; Inhibitor of Differentiation Protein 1 ; Inhibitor of Differentiation Protein 2 ; Phenotype ; Prognosis ; Thyroid Gland* ; Thyroid Neoplasms*

A family of transcription factors known as Id proteins, or inhibitor of DNA binding and differentiation, is capable of regulating cell proliferation, survival and differentiation, and is often upregulated in multiple types of tumors. Due to their ability to promote self-renewal, Id proteins have been considered as oncogenes, and potential therapeutic targets in cancer models. On the contrary, certain Id proteins are reported to act as tumor suppressors in the development of Burkitt's lymphoma in humans, and hepatosplenic and innate-like T cell lymphomas in mice. The contexts and mechanisms by which Id proteins can serve in such contradictory roles to determine tumor outcomes are still not well understood. In this review, we explore the roles of Id proteins in lymphocyte development and tumorigenesis, particularly with respect to inhibition of their canonical DNA binding partners known as E proteins. Transcriptional regulation by E proteins, and their antagonism by Id proteins, act as gatekeepers to ensure appropriate lymphocyte development at key checkpoints. We re-examine the derailment of these regulatory mechanisms in lymphocytes that facilitate tumor development. These mechanistic insights can allow better appreciation of the context-dependent roles of Id proteins in cancers and improve considerations for therapy.
Carcinogenesis ; metabolism ; Cell Physiological Phenomena ; Inhibitor of Differentiation Protein 1 ; metabolism ; Lymphocytes ; physiology ; Transcription Factors ; Tumor Suppressor Proteins ; metabolism

OBJECTIVETo verify the existence and significance of calcium/calmodulin dependent serine protein kinase/inhibitors of differentiation 1 (CASK/Id1) pathway in fibroblasts of human keloid.

METHODSImmunofluorescence laser was used to confirm CASK and Id1 protein expression and localization in fibroblasts of the keloid and normal skin. RT-PCR and Western-blot were adopted to analysis the CASK and Id1 expression and differences between keloid and normal skin fibroblasts. The natural combination of CASK and Id1 protein of keloid fibroblasts was tested by immunoprecipitation.

RESULTSCASK and Id1 protein expression were both found in fibroblast cells of keloid and normal skin under normal circumstances. Most of CASK and Id1 were distributed in the cytoplasm and nucleus of fibroblasts. The results of RT-PCR showed that the expression of CASK mRNA in the keloid group was 0.658 +/- 0.024, which was lower than that in the normal control group (1.076 +/- 0.008, t = 11.159, P < 0.05). The expression of Id1 mRNA was 0.497 +/- 0.014, which was higher than that in the normal control group (0.307 +/- 0.017, t = 15.148, P < 0.05). The results of Western-blot showed that the expression level for CASK protein in the keloid group was 0.057 +/- 0.006, which was lower than that in the normal control group (0.168 +/- 0.012, t = 13.524, P < 0.05); the expression of Id1 protein was 0.812 +/- 0.035, which was higher than that in the normal control group (0.368 +/- 0.031, t = 16.356, P < 0.05). The results of immunoprecipitation showed that Id1 could be detected in the CASK precipitate, while CASK also could be detected in the Id1 precipitate. There was a natural binding of CASK and Id1 in keloid fibroblasts.

CONCLUSIONCASK/Id1 signal pathway may be existed and involved in the proliferation of keloid fibroblasts, which is related with the occurrence of keloid.

Cell Proliferation ; genetics ; Cyclin-Dependent Kinase Inhibitor Proteins ; genetics ; metabolism ; Fibroblasts ; metabolism ; Humans ; Inhibitor of Differentiation Protein 1 ; genetics ; metabolism ; Keloid ; metabolism ; pathology ; RNA, Messenger ; metabolism ; Signal Transduction

OBJECTIVETo study the role of inhibitor of differentiation 1 (ID1) in ATRA-induced acute promyelocytic leukemia (APL) cells differentiation.

METHODSThe expression of ID1 was detected by cDNA microarray, cycloheximide inhibition test, real-time RT-PCR and western blot.

RESULTSThe expression of ID1 gene was up-regulated in ATRA-induced NB4 cells and APL cells from two patients and was independent on other proteins synthesis. ID1 expression level reached the peak at 2 h in NB4 cells induced by ATRA, its relative expression level was (359.4 +/- 48.7)-fold greater than control. ID1 expression level reached the peak at 2 h in bone marrow cells from APL patents treated with ATRA, and its level detected 3 times in one of the patient was (311.1 +/- 48.7) fold of control. The expression of ID1 protein was not up-regulated in ATRA resistant NB4-R2 cells after ATRA treatment.

CONCLUSIONID1 may be involved in ATRA-induced granulocytic differentiation as an ATRA-targeted gene.

Antineoplastic Agents ; therapeutic use ; Cell Differentiation ; Humans ; Inhibitor of Differentiation Protein 1 ; genetics ; metabolism ; Leukemia, Promyelocytic, Acute ; drug therapy ; metabolism ; pathology ; Oligonucleotide Array Sequence Analysis ; Tretinoin ; therapeutic use

OBJECTIVETo isolate the inhibitor of DNA binding 1 (Id1) interaction protein and to determine the role and action mechanism of Id1 in human prostate cancer.

METHODSThe expression vector pET-28a/Id1 was established and used as a bait to prey the interaction protein by pull-down assay.

RESULTSA clear interaction protein band was observed by SDS-PAGE, which was found to be activating transcription factor 3 (ATF3) by Western blotting.

CONCLUSIONId1 may play a role in human prostate cancer by interacting with ATF3.

Activating Transcription Factor 3 ; analysis ; metabolism ; Humans ; Inhibitor of Differentiation Protein 1 ; genetics ; isolation & purification ; metabolism ; Male ; Prostatic Neoplasms ; genetics ; metabolism ; RNA ; Reverse Transcriptase Polymerase Chain Reaction

BACKGROUNDNeural stem cells (NSCs) are a self-renewing and multipotent population of the central nervous system (CNS), which are active during development and maintain homeostasis and tissue integrity throughout life. Microglias are an immune cell population resident in the CNS, which have crucial physiological functions in the developing and adult CNS. This study aimed to investigate that whether microglia co-cultured with NSCs could promote astrogliogenesis from NSCs.

METHODSMicroglia and NSCs were co-cultured in 24-well insert plates. NSCs were plated in the bottom of the well and microglia in the insert. Fluorescent staining, Western blotting and RT-PCR were used to determine the effect of microglia on NSCs differentiation.

RESULTSCo-culture of microglia and NSCs promoted astrogliogenesis from NSCs. Several key genes, such as Notch 1, Notch 2, Notch 3, Hes 5, and NRSF were downregulated, while the critical genes Id1 and Id2 were upregulated. BMP2 and FGF2 were upregulated.

CONCLUSIONMicroglias act as a regulator of NSCs astrogliogenesis.

Animals ; Astrocytes ; cytology ; metabolism ; Basic Helix-Loop-Helix Transcription Factors ; genetics ; Blotting, Western ; Bone Morphogenetic Protein 2 ; genetics ; Cell Differentiation ; genetics ; physiology ; Cells, Cultured ; Coculture Techniques ; methods ; Fibroblast Growth Factor 2 ; genetics ; Inhibitor of Differentiation Protein 1 ; genetics ; Inhibitor of Differentiation Protein 2 ; genetics ; Microglia ; cytology ; metabolism ; Microscopy, Fluorescence ; Neural Stem Cells ; cytology ; metabolism ; Rats ; Repressor Proteins ; genetics ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo observe the effects of thermal stress on proliferation of human vascular endothelial cells (VECs) and explore its significance.

METHODSChanges of VECs proliferation were investigated with (3)H-TdR incorporation method after ECV304 was treated at 43 degrees for 2 hours, while expressions of intercellular adhesion molecule-1 (ICAM-1), inhibitor of differentiation-1 (ID1), and P16 and P21 proteins were determined by Western Blotting.

RESULTSThe effect of inhibition of VECs growth after thermal stress was detected by (3)H-TdR incorporation experiment. Western blotting showed ICAM-1, a marker of activated endothelial cells, was increased markedly after thermal stress. Expression of ID1 protein declined gradually with increasing expressions of its downstream genes, P16 and P21 following the thermal stress.

CONCLUSIONSThermal stress could strongly activate VECs and inhibit proliferation of VECs through ID1, thus down regulating cyclin-dependent kinase inhibitors, P16 and P21, which might be an essential pathway for recovery of VECs after thermal stress.

Blotting, Western ; Cells, Cultured ; Endothelium, Vascular ; cytology ; Helix-Loop-Helix Motifs ; physiology ; Humans ; Inhibitor of Differentiation Protein 1 ; Intercellular Adhesion Molecule-1 ; metabolism ; Repressor Proteins ; Temperature ; Transcription Factors ; metabolism ; Umbilical Veins ; cytology

OBJECTIVETo screen the proteins interacting with inhibitor of differentiation 1(Id1) using yeast two-hybrid analysis in adult human lung cDNA libraries.

METHODSThe coding sequence of Id1 was amplified by PCR and cloned into the bait plasmid. The recombinant bait vector pHybLex/Zeo-Id1 was verified by restriction endonuclease digestion before transformation into the yeast strain EGY48/pSH18-34, which was tested subsequently for reporter genes Leu2 and LacZ activation. The pHybLex/Zeo-Id1 plasmid and the cDNA library plasmid were sequentially transformed into the yeast strains and screened to obtain Leu2(+) and Leu2(+)LacZ(+) clones, with the false positive clones excluded using positive and negative controls, and the plasmid of the true positive clone was sequenced and blasted for homological analysis.

RESULTSSuccessful construction of pHybLex/Zeo-Id1 was confirmed by enzyme digestion. After transformation of pHybLex/Zeo-Id1 into EGY48/pSH18-34, no specific reporter genes Leu2 and LacZ activation was found. The pHybLex/Zeo-Id1 plasmid and the cDNA library plasmid were sequentially transformed into yeast strain, and 198 Leu(+) clones and 19 Leu(+)LacZ(+) double positive clones were obtained. After elimination of the false positive clones, one true positive clone was obtained, whose plasmid analysis by sequencing and blasting indicated high homology (99.5%, 556/559) to AGGF1 (an angiogenic factor with G-patch and FHA domains 1). AGGF1 expression was confirmed in the true positive yeast cells by Western blotting.

CONCLUSIONAGGF1 is confirmed to interact with Id1 by yeast two-hybrid analysis for screening adult human lung cDNA libraries.

Adult ; Angiogenic Proteins ; genetics ; metabolism ; Cell Proliferation ; Endothelial Cells ; cytology ; metabolism ; Gene Library ; Humans ; Inhibitor of Differentiation Protein 1 ; metabolism ; Lung ; cytology ; Plasmids ; genetics ; Protein Binding ; Two-Hybrid System Techniques

OBJECTIVETo investigate the expression of inhibitor of DNA differentiation/DNA binding 1 (Id1) and Id3 in endometrial carcinoma and explore their roles in regulating the proliferation, invasion, migration and adhesion of endometrial carcinoma cells in vitro.

METHODSId1 and Id3 expression in 4 fresh endometrial cancer tissue specimens and matched adjacent tissues were detected using Western blotting. Two endometrial cancer cell lines, HEC-1-B and RL-952, were both divided into 4 groups, namely the untreated group, blank virus group, promoter group and Id1/Id3 double-knockdown group, and their expressions of MMP2, CXCR4 and P21 were detected by qRT-PCR and Western blotting. The proliferation, invasion, migration and adhesion of the cells were evaluated with MTT, Transwell, wound-healing, and adhesion assays.

RESULTSEndometrial carcinoma tissues showed significantly higher Id1 and Id3 expression than the adjacent tissues (P<0.05). In the two endometrial carcinoma cell lines, Id1/Id3 double-knockdown significantly decreased MMP2 and CXCR4 expression and increased P21 expression at both mRNA and protein levels (P<0.05), and resulted in suppressed cell proliferation, invasion, migration and adhesion.

CONCLUSIONId1 and Id3 expressions are up-regulated in endometrial carcinoma to promote the proliferation, invasion, migration and adhesion of the tumor cells by increasing MMP2 and CXCR4 expression and reducing P21 expression. Therapies targeting Id1/Id3 can be a novel strategy for treatment of endometrial carcinoma.

Cell Adhesion ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Endometrial Neoplasms ; metabolism ; pathology ; Female ; Humans ; Inhibitor of Differentiation Protein 1 ; metabolism ; Inhibitor of Differentiation Proteins ; metabolism ; Matrix Metalloproteinase 2 ; metabolism ; Neoplasm Proteins ; metabolism ; Proto-Oncogene Proteins p21(ras) ; metabolism ; RNA Interference ; Receptors, CXCR4 ; metabolism

Objective To explore the expressions of inhibitors of DNA binding-1 (Id-1) and matrix metalloproteinase-9 (MMP-9) in colorectal carcinoma tissues and its correlation with microvessel density (MVD). Methods The expressions of Id-1 and MMP-9 as well as CD34-labelled MVD in colorectal adenocarcinoma tissues (n=50) and normal adjacent tissues (n=50) were examined by immunohistochemistry. Results The positive expressions of Id-1 and MMP-9 were seen in 72.00% (36/50) and 78.00%(39/50) of colorectal adenocarcinoma tissues,which were significantly higher than those [24.00%(12/50) and 28.00% (14/50)] in normal adjacent tissues (P=0.000). The MVD value (17.22±2.08) in colorectal adenocarcinoma tissues was significantly higher than that (5.36±2.17) in normal adjacent tissues (P=0.000). The expressions of Id-1 and MMP-9 and MVD were significantly correlated with serosa invasion,TNM stage,carcinoembryonic antigen(+),lymph node metastasis,vascular invasion,and liver metastasis (all P<0.05) but not with the patient's age,gender,tumor size,and differentiation degree (all P>0.05). The MVD value with Id-1 and MMP-9 positive expression were significantly higher than those with Id-1 and MMP-9 negative expression (all P=0.000). The expression of Id-1 in colorectal adenocarcinoma tissues showed significantly positive correlation with that of MMP-9 (r=0.429,P=0.000). Cox multivariate analysis showed that Id-1 and MMP-9 expressions were independent prognostic factors for colorectal carcinoma. Conclusions The high expressions of Id-1 and MMP-9 have high correlations with the development and progression of colorectal adenocarcinoma and have positive correlation with MVD. Both of them may be involved in the microvascular generation and the invasion and hematogenous metastasis of colorectal carcinoma.
Adenocarcinoma ; blood supply ; metabolism ; Colorectal Neoplasms ; blood supply ; metabolism ; Disease Progression ; Humans ; Immunohistochemistry ; Inhibitor of Differentiation Protein 1 ; metabolism ; Liver Neoplasms ; Lymphatic Metastasis ; Matrix Metalloproteinase 9 ; metabolism ; Microcirculation ; Microvessels ; Neovascularization, Pathologic