Id-1 expression in colorectal adenocarcinoma tissues and its clinical significance.

BACKGROUND: This study aims to investigate the expression of Id-1 in human colorectal adenocarcinoma tissues and explore its correlation with the clinical pathological parameters of colorectal cancer. METHODS: The Id-1 mRNA and protein expression levels of 50 specimens of normal colorectal tissues and 50 specimens of colorectal adenocarcinoma tissues were detected using reverse-transcription polymerase chain reaction and western blot. Furthermore, Id-1 protein was detected using immunohistochemistry. The correlation between the expression of Id-1 and clinicopathologic features was analyzed. RESULTS: The mRNA expression level of Id-1 in colorectal adenocarcinoma tissues and normal colorectal tissues was 0.96 ± 0.03 vs. 0.20 ± 0.04, respectively; and the difference was statistically significant (P=0.011). Furthermore, Id-1 protein expression was higher in colorectal adenocarcinoma tissues than in normal colorectal tissues (0.82 ± 0.04 vs. 0.31 ± 0.02, P=0.020). In addition, the positive protein expression rate of Id-1 was higher in colorectal adenocarcinoma tissues than in normal colorectal tissues (72.00% vs. 24.00%, X2=23.431, P=0.000). The expression of Id-1 was correlated with the depth of tumor invasion, TNM stage, lymph node metastasis, vessel invasion, and liver metastasis (P<0.01). However, this expression was not correlated with tumor size and differentiation degrees (P>0.05). CONCLUSIONS: The high Id-1 expression in colorectal adenocarcinoma tissues play an important role in the process of cancer, and is expected to become a new tumor monitoring indicator for clinical diagnosis, treatment, and prognosis judgment.

Sleep disorders in polycystic ovary syndrome: influence of obesity and hyperandrogenism

SUMMARY OBJECTIVE: This study aims to evaluate the sleep of subjects with polycystic ovary syndrome (PCOS), with and without hyperandrogenism, in comparison with a healthy control group and examine the effects of hyperandrogenism and obesity on sleep parameters. METHODS: A total of 44 volunteers were recruited to participate in the study. Clinical, biochemical and polysomnographic parameters were used to diagnose PCOS and hyperandrogenism. The evaluation of sleep quality was made using validated questionnaires and polysomnography test. The frequency of obstructive sleep apnea was also compared between the groups. RESULTS: The study revealed that women with PCOS presented poorer subjective sleep quality, increased incidence of snoring and a higher risk of obstructive sleep apnea, based on the Berlin questionnaire. Also, after adjusting for body mass index, PCOS subjects had rapid eye movement (REM) time lower than those in the control group. PCOS women versus those without hyperandrogenism did not differ on any sleep measurement. Women with obstructive sleep apnea were only diagnosed in the PCOS group. CONCLUSIONS: Our results indicate that PCOS impairs subjective sleep quality, as well as objective sleep quality, due to a reduction in REM sleep stage time in women diagnosed with the syndrome. Obesity affected sleep-related parameters but hyperandrogenism had no effect. Only the PCOS group had obstructive sleep apnea diagnosis.

RESUMO OBJETIVO: Este estudo objetivou avaliar o sono de mulheres com síndrome do ovário policístico, com e sem hiperandrogenismo, em comparação com um grupo controle saudável, e estudar os efeitos do hiperandrogenismo e da obesidade nos parâmetros do sono. MÉTODOS: Um total de 44 voluntárias foram recrutadas para participar do estudo. Os parâmetros clínicos, bioquímicos e polissonográficos e foram usados para diagnosticar SOP e hiperandrogenismo. A avaliação da qualidade de sono foi feita usando questionários validados e o exame polissonográfico. A frequência de síndrome da apneia obstrutiva também foi comparada entre os grupos. RESULTADOS: O estudo revelou que mulheres com SOP apresentaram menor qualidade de sono subjetiva, incidência aumentada de ronco e maior risco para síndrome da apneia obstrutiva, baseada no questionário de Berlin. Ademais, após o ajuste para índice de massa corpórea, mulheres com SOP tiveram menor tempo de sono REM do que aquelas do grupo controle. Dentre as mulheres com SOP, aquelas com hiperandrogenismo não tiveram diferenças em nenhuma variável do sono. Mulheres com síndrome da apneia obstrutiva foram diagnosticadas no grupo SOP. CONCLUSÕES: Nossos resultados indicam que a SOP afeta a qualidade subjetiva de sono, bem como a qualidade objetiva e do sono, em razão da redução do tempo de sono REM em mulheres diagnosticadas com a síndrome. A obesidade afetou parâmetros relacionados ao sono, mas o hiperandrogenismo não teve efeito. A síndrome da apneia obstrutiva somente foi diagnosticada em mulheres com SOP.

Id-1 expression in colorectal adenocarcinoma tissues and its clinical significance

SUMMARY BACKGROUND: This study aims to investigate the expression of Id-1 in human colorectal adenocarcinoma tissues and explore its correlation with the clinical pathological parameters of colorectal cancer. METHODS: The Id-1 mRNA and protein expression levels of 50 specimens of normal colorectal tissues and 50 specimens of colorectal adenocarcinoma tissues were detected using reverse-transcription polymerase chain reaction and western blot. Furthermore, Id-1 protein was detected using immunohistochemistry. The correlation between the expression of Id-1 and clinicopathologic features was analyzed. RESULTS: The mRNA expression level of Id-1 in colorectal adenocarcinoma tissues and normal colorectal tissues was 0.96 ± 0.03 vs. 0.20 ± 0.04, respectively; and the difference was statistically significant (P=0.011). Furthermore, Id-1 protein expression was higher in colorectal adenocarcinoma tissues than in normal colorectal tissues (0.82 ± 0.04 vs. 0.31 ± 0.02, P=0.020). In addition, the positive protein expression rate of Id-1 was higher in colorectal adenocarcinoma tissues than in normal colorectal tissues (72.00% vs. 24.00%, X2=23.431, P=0.000). The expression of Id-1 was correlated with the depth of tumor invasion, TNM stage, lymph node metastasis, vessel invasion, and liver metastasis (P<0.01). However, this expression was not correlated with tumor size and differentiation degrees (P>0.05). CONCLUSIONS: The high Id-1 expression in colorectal adenocarcinoma tissues play an important role in the process of cancer, and is expected to become a new tumor monitoring indicator for clinical diagnosis, treatment, and prognosis judgment.

RESUMO OBJETIVO: O objetivo deste estudo é investigar a expressão de Id-1 em tecidos de adenocarcinoma colorretal em humanos e investigar sua correlação com os parâmetros patológicos clínicos de câncer colorretal. MÉTODOS: Os níveis de expressão de proteína e mRNA Id-1 em 50 amostras de tecido colorretal normal e 50 amostras de tecido de adenocarcinoma colorretal foram detectados através de reação em cadeia de polimerase precedida de transcrição reversa e western blot. Além disso, a proteína Id-1 foi detectada através de imuno-histoquímica. A correlação entre a expressão de Id-1 e características clínico-patológicas foi analisada. RESULTADOS: O nível de expressão de mRNA Id-1 em tecidos de adenocarcinoma colorretal e tecidos colorretais normais foi de 0,96 ± 0,03 versus 0,20 ± 0,04, respectivamente; a diferença foi estatisticamente significativa (P= 0,011). Além disso, a expressão da proteína Id-1 foi maior em tecidos de adenocarcinoma colorretal do que em tecidos colorretais normais (0,82 ± 0,04 versus 0,31 ± 0,02, P= 0,020). Além disso, a taxa de expressão positiva de proteínas Id-1 foi maior em tecidos de adenocarcinoma colorretal do que em tecidos colorretais normais (72,00% vs. 24,00%, X2=23,431, p=0,000). A expressão de Id-1 foi correlacionada com a profundidade da invasão tumoral, estágio TNM, metástases linfonodais, invasão vascular e metástase hepática (P<0,01). Todavia, essa expressão não se correlacionou com o tamanho do tumor e graus de diferenciação (P>0,05). CONCLUSÃO: A alta expressão de Id-1 em tecidos de adenocarcinoma colorretal desempenham um importante papel no processo do câncer, e é esperado que se torne um novo indicador de monitoramento de tumores para o diagnóstico clínico, tratamento e estimativa de prognóstico.

A 3-Protein Expression Signature of Neuroblastoma for Outcome Prediction.

Neuroblastoma (NB) is the most common extracranial solid tumor in children with contrasting outcomes. Precise risk assessment contributes to prognosis prediction, which is critical for treatment strategy decisions. In this study, we developed a 3-protein predictor model, including the neural stem cell marker Msi1, neural differentiation marker ID1, and proliferation marker proliferating cell nuclear antigen (PCNA), to improve clinical risk assessment of patients with NB. Kaplan-Meier analysis in the microarray data (GSE16476) revealed that low expression of ID1 and high expression of Msi1 and PCNA were associated with poor prognosis in NB patients. Combined application of these 3 markers to constitute a signature further stratified NB patients into different risk subgroups can help obtain more accurate prediction performance. Survival prognostic power of age and Msi1_ID1_PCNA signature by receiver operating characteristics analysis showed that this signature predicted more effectively and sensitively compared with classic risk stratification system, compensating for the deficiency of the prediction function of the age. Furthermore, we validated the expressions of these 3 proteins in neuroblastic tumor spectrum tissues by immunohistochemistry revealed that Msi1 and PCNA exhibited increased expression in NB compared with intermedial ganglioneuroblastoma and benign ganglioneuroma, whereas ID1 levels were reduced in NB. In conclusion, we established a robust risk assessment predictor model based on simple immunohistochemistry for therapeutic decisions of NB patients.

Id-1, Id-2, and Id-3 co-expression correlates with prognosis in stage I and II lung adenocarcinoma patients treated with surgery and adjuvant chemotherapy.

Inhibitors of DNA binding/inhibitors of differentiation (Id) protein family have been shown to be involved in carcinogenesis. However, the roles of Id during lung adenocarcinoma (ADC) progression remain unclear. Eighty-eight ADC samples were evaluated for Id-1,2,3 level and angiogenesis (CD 34 and VEGF microvessel density) by immunohistochemistry and morphometry. The impact of these markers was tested on follow-up until death or recurrence. A significant difference between tumor and normal tissue was found for Id-1,2,3 expression (P < 0.01). In addition, high levels of nuclear Id-1 were associated with higher angiogenesis in the tumor stroma (P < 0.01). Equally significant was the association between patients in T1-stage and low cytoplasmic Id-2, as well as patients in stage-IIb and low Id-3. High cytoplasm Id-3 expression was also directly associated to lymph nodes metastasis (P = 0.05). Patients at stages I to III, with low Id-1 and Id-3 cytoplasm histoscores showed significant long metastasis-free survival time than those with high Id-1 or Id-3 expression (P = 0.04). Furthermore, high MVD-CD34 and MVD-VEGF expression were associated with short recurrence-free survival compared to low MVD-CD34 and MVD-VEGF expressions (P = 0.04). Cox model analyses controlled for age, lymph node metastasis, and adjuvant treatments showed that nuclear Id-1, cytoplasmic Id-3, and MVD-CD34 were significantly associated with survival time. Median score for nuclear Id-1 and cytoplasmic Id-3 divided patients in two groups, being that those with increased Id-1 and Id-3 presented higher risk of death. Ids showed an independent prognostic value in patients with lung ADC, regardless of disease stage. Id-1 and Id-3 should be considered new target candidates in the development of personalized therapy in lung ADC.

Inhibitory effects of PLAP-1/asporin on periodontal ligament cells.

PLAP-1/asporin is an extracellular matrix protein that is predominantly expressed in the human periodontal ligament (PDL) and has an aspartic acid (D) repeat polymorphism in its N-terminal region. In this study, we hypothesized that the D repeat polymorphism of PLAP-1/asporin may affect the physiological functions of periodontal ligaments. We established periodontal ligament cell lines transfected with the D13- or D14-PLAP-1 gene. Alkaline phosphatase staining and alizarin red staining revealed that the cytodifferentiation of the D14-PLAP-1-expressing PDL cells was more repressed compared with that of the D13-PLAP-1-expressing cells. Furthermore, the D14-PLAP-1-expressing cells inhibited BMP-2-induced cytodifferentiation more strongly than did the D13-PLAP-1-expressing cells. Western blotting analysis and luciferase assay revealed that D14-PLAP-1 suppressed BMP-2 signal transduction more efficiently than did D13-PLAP-1, and co-immunoprecipitation demonstrated the stronger affinity of the D14-PLAP-1 protein to BMP-2 compared with the D13-PLAP-1 protein. Analysis of these data suggests that the D repeat polymorphism of PLAP-1/asporin has a significant influence on the functions of PDL cells.

Inhibitor of differentiation proteins do not influence prognosis of biliary tract cancer.

AIM: To investigate the expression and clinical relevance of inhibitor of differentiation (ID) proteins in biliary tract cancer. METHODS: ID protein expression was analyzed in 129 samples from patients with advanced biliary tract cancer (BTC) (45 extrahepatic, 50 intrahepatic, and 34 gallbladder cancers), compared to normal controls and correlated with clinical an pathological parameters. RESULTS: ID1-3 proteins are frequently overexpressed in all BTC subtypes analyzed. No correlation between increased ID protein expression and tumor grading, tumor subtype or treatment response was detected. Survival was influenced primary tumor localization (extrahepatic vs intrahepatic and gall bladder cancer, OS 1.5 years vs 0.9 years vs 0.7 years, P = 0.002), by stage at diagnosis (OS 2.7 years in stage I vs 0.6 years in stage IV, P < 0.001), resection status and response to systemic chemotherapy. In a multivariate model, ID protein expression did not correlate with clinical prognosis. Nevertheless, there was a trend of shorter OS in patients with loss of cytoplasmic ID4 protein expression (P = 0.076). CONCLUSION: ID protein expression is frequently deregulated in BTC but does not influence clinical prognosis. Their usefulness as prognostic biomarkers in BTC is very limited.

Smurf2 regulates the senescence response and suppresses tumorigenesis in mice.

The E3 ubiquitin ligase Smurf2 mediates ubiquitination and degradation of several protein targets involved in tumorigenesis and induces senescence in human cells. However, the functional role of Smurf2 in tumorigenesis has not been fully evaluated. In this study, we generated a mouse model of Smurf2 deficiency to characterize the function of this E3 ligase in tumorigenesis. Smurf2 deficiency attenuated p16 expression and impaired the senescence response of primary mouse embryonic fibroblasts. In support of a functional role in controlling cancer, Smurf2 deficiency increased the susceptibility of mice to spontaneous tumorigenesis, most notably B-cell lymphoma. At a premalignant stage of tumorigenesis, we documented a defective senescence response in the spleens of Smurf2-deficient mice, consistent with a mechanistic link between impaired senescence regulation and increased tumorigenesis. Taken together, our findings offer the genetic evidence of an important tumor suppressor function for Smurf2.

TGF-ß Receptor Inhibitors Target the CD44(high)/Id1(high) Glioma-Initiating Cell Population in Human Glioblastoma.

Glioma-initiating cells (GICs), also called glioma stem cells, are responsible for tumor initiation, relapse, and therapeutic resistance. Here, we show that TGF-ß inhibitors, currently under clinical development, target the GIC compartment in human glioblastoma (GBM) patients. Using patient-derived specimens, we have determined the gene responses to TGF-ß inhibition, which include inhibitors of DNA-binding protein (Id)-1 and -3 transcription factors. We have identified a cell population enriched for GICs that expresses high levels of CD44 and Id1 and tend to be located in a perivascular niche. The inhibition of the TGF-ß pathway decreases the CD44(high)/Id1(high) GIC population through the repression of Id1 and Id3 levels, therefore inhibiting the capacity of cells to initiate tumors. High CD44 and Id1 levels confer poor prognosis in GBM patients.

Expression and importance of inhibitor of DNA binding helix-loop-helix protein in salivary adenoid cystic carcinoma.

Studies have reported that Id-1 (inhibitor of DNA binding, or differentiation 1) protein, helix-loop-helix (HLH) transcription factor, has important roles in the development of several carcinomas. However, the role of Id-1 protein in salivary adenoid cystic carcinoma (ACC) is not clear. The expression of Id-1 protein was assessed in formalin-fixed, paraffin-embedded surgical specimens of ACCs by immunohistochemical staining. Thirty-nine of the 54 specimens of ACC stained for Id-1expression, which was significantly more than was found in pleomorphic adenomas (4/12) and normal salivary gland tissues (1/10, p<0.05). There were also significant differences between stages I and II (7/14) and III-IV (32/40) (p<0.05). Of tumours with metastases, 31/38 stained for Id-1, which was significantly higher than among those without metastases (8/16) (p<0.05). Our results showed that Id-1 may have important roles in the development of salivary ACC. It might also be a useful therapeutic tool to help prevent salivary ACC or to inhibit its malignant progression.

The alteration of Id-1 and TSP-1 expression in mucoepidermoid carcinoma associated with its clinical features and prognosis.

Expression of Id-1 (inhibitors of DNA binding/differentiation protein 1) and TSP-1 (thrombospondin-1) in mucoepidermoid carcinoma and their relationship to pathological features and prognosis was studied. Moderately and poorly differentiated groups had significantly higher Id-1 positive expression rate (p<0.05) than well differentiated carcinoma. Stages III-IV showed significant increase of Id-1 positive expression rate (p<0.05) compared with stages I and II. Id-1 positive expression was significantly higher in patients with cervical lymph node metastasis or relapse at 5 years (p<0.05). After that, patients with negative Id-1 expression had significantly higher tumor-free survival than patients with positive expression (p<0.05). Correlation between the expression of Id-1 and TSP-1 in mucoepidermoid carcinoma was negative (p<0.05). Poorly differentiated groups show significantly lower TSP-1 positive expression rate than well differentiated groups (p<0.05). No significant differences of TSP-1 positive expression were detected with clinical stage. TSP-1 positive expression was significantly lower in patients with cervical lymph node metastasis or relapse at 5 years (p<0.05). After 5 years, patients with positive TSP-1 expression had significantly higher tumor-free survival than patients with negative TSP-1. Positive Id-1 expression is associated with high malignancy/poor prognosis; positive TSP-1 expression is associated with low malignancy/good prognosis. Protein expression status may help assess tumor malignancy and patient prognosis.

The role of Id-1 in chemosensitivity and epirubicin-induced apoptosis in bladder cancer cells.

Recurrence and progression are the major problems in the treatment of bladder cancer. Increased expression of Id-1, a basic helix-loop-helix transcription factor, has recently been shown in several types of advanced cancer. Some studies have provided evidence to suggest that Id-1 can be considered a potential therapeutic target. The objective of this study was to investigate the role of Id-1 in the chemosensitivity of bladder cancer cells, and the effect of Id-1 on chemotherapeutic drug-induced apoptosis in bladder cancer cells. We compared the different sensitivity to epirubicin in RT112 and MGH-U1 cell lines with different Id-1 expression. Then, we transfected different vectors into RT112 and MGH-U1 respectively, and generated the stable Id-1 up-regulation and down-regulation transfectants. The results of cell viability assay showed up-regulation of Id-1 in RT112 leading to increased sensitivity in response to epirubicin, and down-regulation of Id-1 increased cellular sensitivity to epirubicin. Furthermore, the analysis of apoptosis related protein revealed that up-regulation of Id-1 suppressed epirubicin-induced apoptosis and down-regulation of Id-1 leading to increased epirubicin-induced apoptosis. Wound closure assay showed up-regulation of Id-1 leading to improved migration abilities of bladder cancer cells under chemotherapy. Our results suggest that up-regulation of Id-1 in bladder cancer cells lead to increased cell viability in response to epirubicin by its improved anti-apoptotic role, and down-regulation of Id-1 increases cellular sensitivity to epirubicin by increased anticancer drug-induced apoptosis.

Id-1 expression in androgen-dependent prostate cancer is negatively regulated by androgen through androgen receptor.

This study discovered that Id-1 expression in androgen-dependent prostate cancer decreased immediately after androgen deprivation but increased after longer androgen deprivation both in vivo and in vitro. Id-1 expression in androgen-independent LNCaP cells was about 6 fold as that in their parental cells. As was the case with LNCaP cells, when androgen receptor (AR) was introduced into AR-negative PC-3 cells, dihydrotestosterone inhibited while flutamide increased Id-1 expression. Thus, Id-1 expression in androgen-dependent prostate cancer was negatively regulated by androgen in a receptor-dependent way. The re-increased Id-1 might partially contribute to the emergence of androgen-independent prostate cancer after longer androgen deprivation therapy.

The novel Akt inhibitor Palomid 529 (P529) enhances the effect of radiotherapy in prostate cancer.

Radiotherapy (RT) is a common treatment for localised prostate cancer, but can cause important side effects. The therapeutic efficacy of RT can be enhanced by pharmacological compounds that target specific pathways involved in cell survival. This would elicit a similar therapeutic response using lower doses of RT and, in turn, reducing side effects. This study describes the antitumour activity of the novel Akt inhibitor 8-(1-Hydroxy-ethyl)-2-methoxy-3-(4-methoxy-benzyloxy)-benzo[c]chromen-6-one (Palomid 529 or P529) as well as its ability to decrease radiation-activated phospho-Akt (p-Akt) signalling in a prostate cancer model. P529 showed a potent antiproliferative activity in the NCI-60 cell lines panel, with growth inhibitory 50 (GI50) <35 microM. In addition, P529 significantly enhanced the antiproliferative effect of radiation in prostate cancer cells (PC-3). Analysis of signalling pathways targeted by P529 exhibited a decrease in p-Akt, VEGF, MMP-2, MMP-9, and Id-1 levels after radiation treatment. Moreover, the Bcl-2/Bax ratio was also reduced. Treatment of PC-3 tumour-bearing mice with 20 mg kg(-1) P529 or 6 Gy radiation dose decreased tumour size by 42.9 and 53%, respectively. Combination of both treatments resulted in 77.4% tumour shrinkage. Decreased tumour growth was due to reduced proliferation and increased apoptosis (as assessed by PCNA and caspase-3 immunostaining). Our results show the antitumour efficacy of P529 alone, and as a radiosensitiser, and suggest that this compound could be used in the future to treat human prostate cancer.

Humoral factors released from human periodontal ligament cells influence calcification and proliferation in human bone marrow mesenchymal stem cells.

BACKGROUND: Transplantation of bone marrow mesenchymal stem cells (MSCs) is believed to be a new modality for periodontal tissue regeneration. However, little is known about the factors that influence the functions of the transplanted MSCs. Periodontal ligament cells may be implicated in regulating MSC functions. METHODS: To examine the effect of humoral factors (HFs) produced by human periodontal ligament (HPL) cells on human MSC (hMSC) gene expression, hMSCs were cocultured separately with HPL cells. The gene expression of the hMSCs was analyzed by microarray. Moreover, the effect of conditioned medium (CM) from cultures of HPL cells (CM-HPL cells) on the proliferation and mineralizing capacity of hMSCs was examined. RESULTS: Thirty-five genes whose expressions were upregulated more than two-fold and 32 genes whose expressions were downregulated more than two-fold were identified in hMSCs cocultured separately with HPL cells. CM-HPL cells prevented calcification in hMSCs cultured with bone morphogenetic protein-2 but not dexamethasone. CM-HPL cells stimulated cell proliferation in hMSCs, whereas CM from culture of human osteoblasts did not influence the proliferation. CONCLUSIONS: To the best of our knowledge, this is the first study on the global gene expression of MSCs cocultured with periodontal ligament cells. A particular humoral factor released from periodontal ligament cells is suggested to affect differentiation and proliferation in MSCs.

Increased expression of Id family proteins in small cell lung cancer and its prognostic significance.

PURPOSE: To study the molecular pathology of human small cell lung cancer (SCLC), molecular biology approaches were used to identify genes involved in malignant progression of the cancer cells. EXPERIMENTAL DESIGN: Microquantity differential display was used initially to identify genes expressed differentially between normal and malignant cell lines. The differences were verified by Western blot. Immunohistochemical analysis was done on paired normal and malignant lung tissues and on tissues taken by biopsy to assess the expression status of candidate genes and their prognostic significance. RESULTS: Inhibitor of DNA/differentiation (Id)1 gene was up-regulated in SCLC cells. Levels of Id1 in 8 of 10 cell lines were increased by 1.7- to 21.4-fold when compared with the benign cells. A similar increase was also found in levels of Id2 and Id3. On 26 pairs of lung tissues, all four Id proteins were significantly (Wilcoxon Signed Rank Test, P < 0.001-0.005) overexpressed in cytoplasm of the malignant cells. In nuclei of SCLC cells, Id1 expression was significantly reduced, whereas the levels of Id2, Id3, and Id4 were significantly (Wilcoxon Signed Rank Test, P < 0.001) increased. Immunohistochemical staining on biopsy specimens showed that the increased expression of Id2 in cytoplasm of cancer cells, not the other three proteins, was significantly associated with the increased survival of SCLC patients. CONCLUSION: Changed expression profiles of Id proteins may play important roles in malignant progression of SCLC, and the increased Id2 in cytoplasm is a novel prognostic factor to predict the patient outcomes.

Overexpression of Id-1 protein is a marker in colorectal cancer progression.

The inhibitor of differentiation/DNA binding 1 (Id-1), a negative regulator of basic helix-loop-helix transcription factors, plays an important role in the regulation of cell proliferation and differentiation. We examined the Id-1 expression by immunohistochemistry in 9 adenomas, 79 primary colorectal adenocarcinomas matched with 40 adjacent normal mucosa specimens and its relationship with clinicopathological factors. The Id-1 expression was increased in the carcinoma compared to the adjacent normal mucosa either in the unmatched and matched samples or to the adenoma. There was no significant difference in the Id-1 expression between normal mucosa and adenoma. The Id-1 expression of carcinoma was increased from Dukes' stages A to B, to C and to D. The cases with lymph node metastasis had a higher rate of a stronger Id-1 expression than those without lymph node metastasis. In conclusion, Id-1 overexpression plays an important role in colorectal cancer progression.

BMP-6 over-expression in prostate cancer is associated with increased Id-1 protein and a more invasive phenotype.

Bone morphogenetic protein-6 (BMP-6) has been strongly implicated in prostate cancer development and bone metastasis. Our previous data showed that BMP-6 mRNA was absent in patients with benign prostatic hyperplasia, but evident in primary tumours with established secondary skeletal metastases. To examine the role of BMP-6 in prostate cancer progression, we have developed a BMP-6-regulatable, doxycycline-inducible gene expression system. BMP-6 induction by doxycycline addition led to increased levels of BMP-6 RNA and protein, associated with nuclear translocation of SMADs and activation of the downstream target gene Id-1. BMP-6 protein did not enhance the proliferation rate of PC3M cells but did significantly increase the rate of migration and invasion in both PC3M and DU145 cells. Increased metalloproteinase (MMP-1 and MMP-9) mRNA levels were also observed following BMP-6 induction. Luciferase reporter assays confirmed BMP-6-mediated activation of MMP-1 and MMP-9 promoters, indicating direct transcriptional activation of MMPs by BMP-6. BMP-6 stimulation also led to an increase in phosphorylation levels of MAPK proteins. We next examined the effects of BMP-6 on the downstream gene Id-1 in a cohort of prostate cancer patients. A tissue microarray (TMA) was constructed and samples stained for BMP-6 and Id-1 expression. We observed a significant increase in the intensity of staining of epithelial BMP-6 in the cancer cases compared to the benign cases (Mann-Whitney U test, p < 0.0005) and in the intensity of staining of epithelial Id-1 in the cancer cases compared to the benign cases (Mann-Whitney U test, p = 0.015). We further observed a significant positive correlation between epithelial staining for Id-1 and BMP-6 (p = 0.001) across all samples for both benign and cancer cases. These data demonstrate that BMP-6 promotes migration and invasion of prostate cancer cells, potentially through activation of Id-1 and MMP activation.

ID genes mediate tumor reinitiation during breast cancer lung metastasis.

The establishment of distant metastases depends on the capacity of small numbers of cancer cells to regenerate a tumor after entering a target tissue. The mechanisms that confer this capacity remain to be defined. Here we identify a role for the transcriptional inhibitors of differentiation Id1 and Id3 as selective mediators of lung metastatic colonization in the triple negative [TN, i.e., lacking expression of estrogen receptor and progesterone receptor, and lacking Her2 (human epidermal growth factor receptor 2) amplification] subgroup of human breast cancer. Although broad expression of Id1 has recently been documented in tumors of the rare metaplastic subtype, here we report that rare Id1-expressing cells are also present in the more common TN subset of human breast tumors but not in other subtypes. We also provide evidence that Id1 expression is enriched in clinically obtained hormone receptor negative lung metastases. Functional studies demonstrate that Id1 and its closely related family member Id3 are required for tumor initiating functions, both in the context of primary tumor formation and during metastatic colonization of the lung microenvironment. In vivo characterization of lung metastatic progression reveals that Id1 and Id3 facilitate sustained proliferation during the early stages of metastatic colonization, subsequent to extravasation into the lung parenchyma. These results shed light on the proliferative mechanisms that initiate metastatic colonization, and they implicate Id1 and Id3 as mediators of this malignant function in the TN subgroup of breast cancers.

Inhibitor of differentiation 1 promotes endothelial survival in a bleomycin model of lung injury in mice.

The Id family of genes encodes negative regulators of basic helix-loop-helix transcription factors and has been implicated in diverse cellular processes such as proliferation, apoptosis, differentiation, and migration. However, the specific role of Id1 in lung injury has not been investigated. Bleomycin has been widely used to generate animal models of acute lung injury and fibrogenesis. In this study we found that, on bleomycin challenge, Id1 expression was significantly up-regulated in the lungs, predominantly in endothelial cells, as revealed by double immunolabeling and quantitative flow cytometric analysis. Mice with Id1 loss-of-function (Id1(-/-)) displayed increased vascular permeability and endothelial apoptosis in the lungs after bleomycin-induced injury. Cultured Id1(-/-) lung microvascular endothelial cells also showed decreased survival when exposed to bleomycin. We detected a decrease in the level of Bcl-2, a primary anti-apoptotic protein, in Id1(-/-) endothelial cells, suggesting that down-regulated Bcl-2 may promote endothelial apoptosis in the lung. Therefore, we propose that Id1 plays a crucial role in promoting endothelial survival in the adult lung on injury. In addition, bleomycin-exposed Id1(-/-) mice showed increased lung collagen accumulation and fibrogenesis, suggesting that Id1 up-regulation in the lung may play a critical role in lung homeostasis.