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 investigate the changes of ID1 expression in tumor cells treated with etoposide, cisplatin and ultraviolet (UV) irradiation, and explore the effect of ID1 on chemotherapeutic drug- and UV-induced apoptosis.

METHODSIn the present study, upon onset of apoptosis induced by various kinds of inducers such as etoposide, cisplatin and UV irradiation, the expression level of ID1 was detected by Western blot and real-time PCR. We also analyzed the half-life of ID1 protein and stability of ID1 mRNA respectively by cycloheximide inhibition test and RT-PCR. Annexin-V assay was carried out to evaluate the contribution of ID1 protein to chemotherapeutic drug- and UV-induced apoptosis.

RESULTSID1 expression presented a profound down-regulation in the HCT116 cells treated with etoposide, cisplatin and UV irradiation(P<0.05 for all). The apoptosis in the UV irradiation group, cisplatin group, etoposide group was (58.70±1.55)%, (35.80±0.92)% and (21.00±0.72)%, respectively, significantly higher than that of the control group(1.10±0.07)%, (1.20±0.13)% and (3.50±0.23)% (P<0.05 for all). Upon etoposide treatment, ID1 expression level was decreased via induction of mRNA instability, but not the protein degradation changes. Additionally, ectopic expression of ID1 in the HCT116 cells alleviated etoposide-, cisplatin- and UV-induced apoptosis. The results of flow eytometry revealed that the percentage of apoptotic cells in the ID1 group under the treatment of etoposide, cisplatin and UV irradiation was (23.80±0.82)%, (17.80±1.34)% and (13.40±0.53)%, respectively, significantly lower than that in the empty vector group (41.10±1.61)%, (30.40±2.67)% and (22.50±3.47)% (P<0.05 for all).

CONCLUSIONSThese observations indicate that the treatment with etoposide reduces the amount of ID1 by induction of mRNA instability, and exogenously introduced ID1 protects cells against etoposide-, cisplatin- and UV irradiation-induced apoptosis. Inhibition of the ID1 bioactivity may become a new strategy in cancer treatment.

Antineoplastic Agents ; pharmacology ; Apoptosis ; Cisplatin ; pharmacology ; Down-Regulation ; Etoposide ; pharmacology ; HCT116 Cells ; drug effects ; metabolism ; radiation effects ; Half-Life ; Humans ; Inhibitor of Differentiation Protein 1 ; genetics ; metabolism ; RNA, Messenger ; metabolism ; Real-Time Polymerase Chain Reaction ; Ultraviolet Rays

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

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 verify whether abnormal expression of calcium/calmodulin dependent serine protein kinase (CASK) and inhibitors of differentiation 1 (ID1) exist in Fb of keloid, and to observe the effect of artesunate on two genes.

METHODSFifteen samples of keloid and 12 samples of normal skin tissue (discarded) excised from patients admitted to our hospital were collected. Tissue particle adherent method was used in the primary culture of Fb, and cells from the third to the eighth passage were used for test. Expressions of CASK and ID1 in Fb harvested from both sources were observed with immunofluorescence staining. Fb of keloid were stimulated with artesunate in various concentration for different time, and the median inhibitory concentration (IC50) was determined with the MTT colorimetric assay, which served as the intervention concentration of artesunate. Fb of normal skin were set as normal control group (NC, treated with medium solution). Fb of keloid were divided into scar control group (SC, treated with medium solution) and scar administration group (SA, treated with artesunate in IC50). The cycle and apoptosis of Fb were detected with flow cytometric assay, and the nucleic acid and protein expressions of CASK and ID1 of Fb in each group were determined with RT-PCR and Western blotting. Data were processed with one-way analysis of variance and LSD-t test.

RESULTSExpressions of CASK and ID1 were detected in two kinds of Fb. The concentration of 75 mg/L was selected as the intervention concentration of artesunate. (1) There were statistically significant differences among the three groups in the percentages of cells in G0/G1 phase and G2/M phase (with F values respectively 118.064 and 163.840, P values all below 0.01). The percentage of cells in G0/G1 phase of group SA was (91.4 ± 1.4)%, which was significantly higher than that of group SC and group NC [respectively (80.7 ± 0.3)% and (82.4 ± 0.6)%, with t values respectively 12.740 and 9.872, P values all below 0.05]. The percentage of cells in G2/M phase of group SA was (6.9 ± 0.3)%, which was significantly lower than that of group SC and group NC [respectively (13.7 ± 0.3)% and (12.7 ± 0.8)%, with t values respectively 43.702 and 12.276, P values all below 0.05]. (2) There were statistically significant differences among the three groups in the early and late apoptotic rates (with F values respectively 61.879 and 4710.862, P values all below 0.01). The early and late apoptotic rates of group SA were respectively (7.1 ± 1.0)% and (14.9 ± 0.3)%, which were significantly higher than those of group SC and group NC [with early apoptotic rate respectively (2.6 ± 0.4)% and (2.7 ± 0.3)%, t values respectively 7.974 and 7.767, P values all below 0.05; with late apoptotic rate respectively (2.3 ± 0.3)% and (2.5 ± 0.4)%, t values respectively 72.882 and 69.792, P values all below 0.05]. (3) The mRNA expression of CASK in group SC was 0.658 ± 0.024, and it was lower than that of group NC (1.076 ± 0.008, t = 28.997, P < 0.01) and group SA (0.855 ± 0.008, t = 13.549, P < 0.01). The protein expression of CASK in group SC was 0.067 ± 0.007, and it was lower than that of group NC (0.179 ± 0.015, t = 12.042, P < 0.01) and group SA (0.132 ± 0.010, t = 9.498, P < 0.01). (4) The mRNA expression of ID1 in group SC was 0.416 ± 0.006, which was higher than that of group NC (0.317 ± 0.020, t = 8.299, P < 0.01) and group SA (0.217 ± 0.009, t = 32.417, P < 0.01). The protein expression of ID1 in group SC was 0.789 ± 0.034, and it was higher than that of group NC (0.366 ± 0.029, t = 16.341, P < 0.01) and group SA (0.114 ± 0.006, t = 33.978, P < 0.01).

CONCLUSIONSIt is speculated that CASK and ID1 participate in the proliferation of Fb in keloid. The mechanism of artesunate in inhibiting the proliferation of Fb in keloid may be related to the up-regulation of CASK and down-regulation of ID1.

Adolescent ; Adult ; Apoptosis ; drug effects ; Artemisinins ; pharmacology ; Cell Proliferation ; drug effects ; Cells, Cultured ; Female ; Fibroblasts ; metabolism ; Gene Expression Regulation ; Guanylate Kinases ; genetics ; metabolism ; Humans ; Inhibitor of Differentiation Protein 1 ; genetics ; metabolism ; Keloid ; metabolism ; pathology ; Male ; Middle Aged ; Young Adult

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

The formation of osteolytic bone lesions is a key process for osteolytic cancer to metastasize to the bone and is under the control of a set of transcription factors. Recently, the inhibitor of differentiation 1 (Id1) has been linked with angiogenesis, tumorigenesis, metastasis and bone formation. However, the function of Id1 during the process of bone destruction caused by cancer in vivo has not yet been elucidated. We, therefore, examined whether and how Id1 affects the ability of cancer to form osteolytic lesion in vivo. The study used a lentiviral vector overexpressing short hairpin RNA (shRNA) targeting Id1 gene. PC3 cells, a prostate cancer cell line, were transduced with Id1 shRNA or negative control (NC) shRNA before implantation in BALB/c mice. Cells were implanted in a tibial injection model. Tumor formation in bone was monitored by X-ray. The relationship between parathyroid hormone-related protein (PTHrP), an osteolytic factor, and Id1 was analyzed by using immunohistochemistry in tissue sections from osteolytic lesion of the BALB/c mice. Our results showed that Id1 shRNA delivery to PC3 cells by lentivirus caused efficient and stable Id1 gene silencing. In the intratibial model, PC3 cells produced primarily osteolytic lesions in the bone. Eleven of 14 mice in Id1 shRNA group but only 4 of 14 mice in the NC shRNA group developed osteolytic lesions with cortical destruction at 4th week. Mice treated with Id1 shRNA had larger tumor volume in the bone and larger cortical destruction. The expression of PTHrP protein in PC3 cells was not affected by Id1 knockdown in vivo. These results indicate that Id1 may down-regulate the ability of PC3 cells to form osteolytic lesions in vivo and the signal pathway needs to be further investigated.
Animals ; Bone Neoplasms ; genetics ; metabolism ; secondary ; Cell Line, Tumor ; Gene Silencing ; Humans ; Inhibitor of Differentiation Protein 1 ; genetics ; metabolism ; Male ; Mice ; Mice, Inbred BALB C ; Osteolysis ; genetics ; metabolism ; pathology ; Prostatic Neoplasms ; genetics ; metabolism ; pathology

OBJECTIVETo explore the expression and clinical significance of ID1 gene in acute myeloid leukemia (AML) patients.

METHODReal-time quantitative PCR (RQ-PCR) was used to test the expression level of ID1 gene in 114 de novo adult AML patients, and the clinical features of these patients were analyzed.

RESULTSID1 gene transcript levels were detectable in BM mononuclear cells from 114 patients with AML, the median expression level of all samples was 8525 (range: 57 - 11 233 238). There was a statistically significant difference on expression level of ID1 gene among the three different cytogenetic prognosis groups, and the poor prognosis group (median: 36 840, range: 336 - 11 233 238) harbored the significantly higher level of ID1 gene than the intermediate prognosis group (Median: 6630, range: 66 - 1 840 798) (P = 0.006). The expression level of ID1 gene was positively associated with older age (age ≥ 60 years vs < 60 years, P = 0.002) and higher WBC count (WBC ≥ 10×10(9)/L vs < 10×10(9)/L, P = 0.005). Young patients (age < 60 years) who were not obtained the complete remission (non-CR) after the first cycle of chemotherapy harbored the high level of ID1 gene (Median: 9537 of non-CR vs 1268 of CR, P = 0.010).

CONCLUSIONSHigh expression level of ID1 gene was mostly seen in AML patients with adverse cytogenetics and older age (age ≥ 60 years), and may be associated with poor prognosis of AML. ID1 gene might be a prognostic molecular marker of AML.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Case-Control Studies ; Female ; Humans ; Inhibitor of Differentiation Protein 1 ; genetics ; metabolism ; Leukemia, Myeloid, Acute ; diagnosis ; genetics ; metabolism ; Male ; Middle Aged ; Prognosis ; Young Adult

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

The peroxisome proliferator activated receptor (PPAR)gamma agonist is used as antidiabetic agent with antihyperglycemic and antihyperinsulinemic actions. Beyond these actions, antifibrotic effects have been reported. We examined antifibrotic effects of PPARgamma agonist and interaction with angiotensin receptor antagonist in the unilateral ureteral obstruction (UUO) model. After UUO, mice were divided to four groups: no treatment (CONT), pioglitazone treatment, L158809 treatment, and L158809+ pioglitazone treatment. On day 14, CONT mice showed severe fibrosis and all treated mice showed decreased fibrosis. The immunohistochmistry of PAI-1, F4/80 and p-Smad2 demonstrated that their expressions were increased in CONT group and decreased in the all treated groups compared to CONT. PAI-1 and p-Smad2 determined from Western blotting, among treated groups, was decreased compared to CONT group. The expression of TGF-beta1 from real time RT PCR showed markedly increased in the CONT group and decreased in all treated groups compared to CONT. These data suggest the pioglitazone inhibited tubulointerstitial fibrosis, however, the synergism between pioglitazone and L158809 is not clear. Considering decreased expression of PAI-1 and TGF-beta/Smad2 in the treated groups, PAI-1 and TGF-beta are likely linked to the decreased renal tubulointerstitial fibrosis. According to these results, the PPARgamma agonist might be used in the treatment of renal fibrotic disease.
*Angiotensin Receptor Antagonists ; Animals ; Antigens, Differentiation/metabolism ; Disease Models, Animal ; Fibrosis ; Hypoglycemic Agents/pharmacology ; Kidney/metabolism/*pathology ; Male ; Mice ; Mice, Inbred C57BL ; PPAR gamma/*agonists ; Plasminogen Activator Inhibitor 1/metabolism ; Smad2 Protein/metabolism ; Thiazolidinediones/pharmacology ; Transforming Growth Factor beta1/genetics/metabolism ; Ureteral Obstruction/metabolism/pathology