MIB-1 Overexpression Research Articles

The E3 Ligase MIB1 Promotes Proteasomal Degradation of NRF2 and Sensitizes Lung Cancer Cells to Ferroptosis.

Dysregulation of Notch signaling has been implicated in cellular transformation and tumorigenesis in a variety of cancers while potential roles of MIB1, an E3 ubiquitin ligase required for efficient Notch activation, remains to be investigated. We analyzed MIB1 expression levels in tumor samples and performed gain-of-function and loss-of-function studies in cell lines to investigate potential roles of MIB1 in epithelial-to-mesenchymal transition (EMT), cell migration, and cell survival. We found that overexpression of MIB1 is detected in a subset of lung squamous carcinoma and adenocarcinoma samples and negative correlation is observed between MIB1 expression and overall patient survival. Ectopic expression of MIB1 in A549 cells induces EMT and stimulates cell migration via a Notch-dependent pathway. Meanwhile, MIB1 stimulates the degradation of nuclear factor erythroid 2-related factor 2 (NRF2) in a Notch-independent manner and disrupts the antioxidant capacity of cells, rendering them more sensitive to inducers of ferroptosis. On the other hand, MIB1 knockout induces accumulation of NRF2 and resistance to ferroptosis. Collectively, these results indicate that MIB1 may function as a positive regulator of ferroptosis through targeted degradation of the master antioxidant transcription factor NRF2. IMPLICATIONS: This study identifies a MIB1-induced proteasomal degradation pathway for NRF2 and reveals elevated ferroptosis sensitivity in MIB1-overexpressing cells which may provide novel insights into the treatment of MIB1-overexpressing cancers.

Study on the overexpression of succinate dehydrogenase B and MIB-1 in pheochromocytoma/paraganglioma tissue

Objective We aimed to investigate the overexpression of succinic dehydrogenase (SDH)B and MIB-1 in patients with pheochromocytoma/paraganglioma(PHEO/PGLs) and its significance for predicting the clinical malignant behavior. Methods From August 2008 to April 2016, the clinical characteristics of 93 patients with PHEO/PGLs were analyzed retrospectively. There were 57 males and 36 females. with an average of 34 years, ranging 8-73 years old. There were 68 cases of adrenal pheochromocytoma and 25 cases of paraganglioma. There were 79 cases with hypertension and 14 cases of adrenal accidental tumors. Sixty-six cases with typical hyper-catecholamine secretion symptoms and 27 cases with non-functional PHEO/PGL. Benign PHEO/PGLs were 77 cases and malignant 16 cases. The tumor was located on the left side in 39 cases, on the right side in 32 cases and multiple lesions in 22 cases. The diameter of the PHEO/PGL tumor was (6.8±2.7) cm. The 24 h urine catecholamine was measured before operation, which showed epinephrine was(42.6±5.1)μg/24 h, norepinephrine was(167.5±13.5)μg/24h and dopamine was (246.4±71.2)μg/24h. Six cases wihtout hereditary diseases of urinary system were selected as normal control group. SDHB, SDHAF2, SDHC, SDHD, VHL and RET gene mutations were detected in all patients. Immunohistochemical panel has been performed to detect the expression of SDHB, MIB-1, EPAS1, VEGF-1 receptor (VEGF-1R), and chromain A (CgA) in 93 specimens of PHEO/PGL tissue. The positive granular cytoplasm staining >50% was strongly positive (+ + + ), 11% to 50% was moderately positive (+ + ), 1% to 10% was weak positive (+ ) and the negative was compared with the known positive internal reference, that is, there was less than 1% or no stain completely. Results SDHB, SDHAF2, SDHC, SDHD, VHL and RET gene mutations in 27 cases (29.5%). Nine patients with SDHB gene mutation (9.7%). RET proto-oncogene mutations in 8 cases (8.6%). 3 cases had VHL mutation (3.2%). Immunohistochemical staining showed that MIB-1 positive expression was found in 7 of 9 patients with SDHB gene mutation. Six cases in the control group were negative for gene detection and MIB-1, EPAS1, CgA and VEGF-1R immunohistochemical results. EPAS1 showed moderately positive in patients with PHEO/PGL and strong positive in patients with malignant PHEO/PGL. In 9 cases with SDHM mutation, EPAS1 was noticed positive in seven cases, which showed the relationship with CgA, MIB-1 and VEGF-1R. Conclusions The SDHB gene mutation is usually shown as a paraganglioma focus outside the adrenal gland. And 9.8% of the paragangliomas were associated with a mutation of the SDHB gene with an increase in malignant risk. The SDHB mutation caused over-expression of MIB-1 and the positive expression of EPAS1 and VEGF-1R in PHEO/PGL tissues, which was associated with invasion and metastasis of malignant PHEO/PGL. Key words: Pheochromocytoma; Paraganglioma; Succinate dehydrogenase B

The Notch ligand E3 ligase, Mind Bomb1, regulates glutamate receptor localization in Drosophila.

The postsynaptic density (PSD) is a protein-rich network important for the localization of postsynaptic glutamate receptors (GluRs) and for signaling downstream of these receptors. Although hundreds of PSD proteins have been identified, many are functionally uncharacterized. We conducted a reverse genetic screen for mutations that affected GluR localization using Drosophila genes that encode homologs of mammalian PSD proteins. 42.8% of the mutants analyzed exhibited a significant change in GluR localization at the third instar larval neuromuscular junction (NMJ), a model synapse that expresses homologs of AMPA receptors. We identified the E3 ubiquitin ligase, Mib1, which promotes Notch signaling, as a regulator of synaptic GluR localization. Mib1 positively regulates the localization of the GluR subunits GluRIIA, GluRIIB, and GluRIIC. Mutations in mib1 and ubiquitous expression of Mib1 that lacks its ubiquitin ligase activity result in the loss of synaptic GluRIIA-containing receptors. In contrast, overexpression of Mib1 in all tissues increases postsynaptic levels of GluRIIA. Cellular levels of Mib1 are also important for the structure of the presynaptic motor neuron. While deficient Mib1 signaling leads to overgrowth of the NMJ, ubiquitous overexpression of Mib1 results in a reduction in the number of presynaptic motor neuron boutons and branches. These synaptic changes may be secondary to attenuated glutamate release from the presynaptic motor neuron in mib1 mutants as mib1 mutants exhibit significant reductions in the vesicle-associated protein cysteine string protein and in the frequency of spontaneous neurotransmission.

The Prognostic Role of Ki-67/MIB-1 in Upper Urinary-Tract Urothelial Carcinomas: A Systematic Review and Meta-Analysis.

Upper urinary-tract urothelial carcinomas (UTUC) constitute 5% of urothelial malignancies. Prognostic biomarkers would allow lower risk surgical approaches for less aggressive UTUCs. One biomarker-Ki-67/mindbomb E3 ubiquitin protein ligase 1 (Ki-67/MIB-1)-shows promise in UTUC, but there have been conflicting findings regarding its prognostic role. The systematic review and meta-analysis aim to determine the prognostic value of Ki-67/MIB-1 in UTUC in terms of UTUC-specific mortality rate, 5-year disease-free survival, and 5-year overall survival (including disease-specific survival). A systematic review of the current literature produced 654 records. A total of 13 studies consisting of 1030 patients were finally included in the meta-analysis. Hazard ratios (HRs) with 95% confidence intervals (CI) were extracted or estimated. The individual HR estimates were combined into a pooled HR using a fixed-effects model that summed homogeneity of the individual true HRs. Patients with Ki-67/MIB-1 overexpression displayed significantly higher UTUC-specific mortality rate (pooled HR: 2.14, 95% CI: 1.73-2.64; p<0.00001), significantly reduced 5-year disease-free survival (pooled HR: 2.27, 95% CI: 1.79-2.92; p<0.00001), and significantly reduced 5-year overall survival (pooled HR=1.77; 95% CI: 1.39-2.23 p<0.00001). There was significant heterogeneity detected in the UTUC-specific mortality rate meta-analysis (I(2)=63%) and the 5-year disease-free survival meta-analysis (I(2)=65%), but there was no significant heterogeneity detected in the 5-year overall survival meta-analysis (I(2)=0%). Egger's testing showed that none of the outcomes were influenced by publication bias (p>0.05). Ki-67/MIB-1 overexpression shows promise as a prognostic biomarker for UTUC patients and requires further investigation.

Cilia born out of shock and stress

Primary cilia are cell surface sensory organelles, whose dysfunction underlies various human genetic diseases collectively termed ciliopathies. A new study in The EMBO Journal by Villumsen et al now reveals how stress–response pathways converge to stimulate ciliogenesis by modulating protein composition of centriolar satellites. Better understanding of these mechanisms should bring us closer to identifying the cellular defects that underlie ciliopathies caused by mutations in centriolar satellite proteins. Centrioles are barrel‐shaped structures with two distinct identities. In proliferating cells centrioles provide structural support for the centrosome, a key microtubule‐organizing centre, whereas in quiescent cells centrioles are converted into basal bodies and promote the assembly of primary cilia. In centrosomes, centrioles are embedded in pericentriolar material (PCM), a dynamic structure responsible for microtubule nucleation. PCM proteins exhibit cell cycle‐dependent localisation, achieved at least in part by the regulation of their transport. Centriolar satellites, dense fibrous granules frequently clustered around the interphase centrosome, have been implicated in microtubule‐dependent protein transport to centrosomes (Kubo et al, 1999). In particular, PCM‐1, the core constituent of centriolar satellites, is required for centrosomal accumulation of several PCM components (Dammermann and Merdes, 2002). Although the proteomic composition of satellites is still elusive, the growing list of satellite proteins includes CEP131/AZI1 (Staples et al, 2012), CEP290 (Stowe et al, 2012), Bardet‐Biedl syndrome protein 4 (BBS4) and Oral facial digital syndrome protein (OFD1; Lopes et al, 2011). Mutations in OFD1, CEP290 and BBS4 cause ciliopathies (Kim et al, 2008), underscoring a functional link between satellites and ciliogenesis. So far, two roles have been proposed for satellites in cilia formation: …

Impact of the expression of Aurora-A, p53, and MIB-1 on the prognosis of urothelial carcinomas of the upper urinary tract

ObjectivesTo investigate whether overexpression of p53, MIB-1, and Aurora-A on protein level played a role in the relapse of urothelial carcinomas of the upper urinary tract (UC-UUT). Materials and methodsThe following data from the files of 42 patients treated for UC-UUT were collated: age, prior history of cancer, tumor stage and grade, and disease progression. Immunohistochemistry (IHC) for p53, MIB-1, and Aurora-A was performed on tissue microarray sections from tumor tissue. ResultsPatients aged 46 to 100 years (mean 70.6 years). Overall, 23 (54%) patients died from progression of UT-UCC. The surgical stage was significantly associated with MIB-1 and Aurora-A overexpression (P = 0.004 for each). Univariate analysis showed that relapse was significantly associated with ureteral localization (P = 0.02), the presence of vascular invasion (VI) (P = 0.003), high grade (P = 0.04), high stage UT-UCCs (P = 0.02), and p53 (P = 0.01), Aurora-A (P = 0.01), and MIB-1 overexpression (P = 0.02). In multivariate analysis, relapse was associated with high grade (P = 0.04), high stage (P = 0.04), VI (P < 0.0001, respectively), and p53 (P = 0.04) and Aurora-A (P = 0.02) overexpression but not with MIB-1 overexpression (P = 0.06). In addition, expressions of p53, MIB-1, and Aurora-A were significantly associated with presence of VI (P = 0.008, P = 0.001, and P = 0.003, respectively). ConclusionAurora-A and p53 are important factors in UC-UUT development and might be useful as independent factors for predicting clinical outcome and presence of VI. Aurora-A seems to influence the development of VI and tumor aggressiveness via a mechanism not clearly elucidated yet.

P16INK4A and MIB-1: An immunohistochemical expression in preneoplasia and neoplasia of the cervix

To evaluate the potential of p16INK4A and MIB-1 and to compare the expression and interrelationship of these markers in cervical preneoplasias and neoplasias. Immunohistochemical analysis of p16 and MIB-1 was performed in n = 63 tissue sections and by matching the corresponding Papanicolaou smears. Staining intensity for p16 was determined using the 0-3 grading system. For MIB-1, labelling indices (LI) were calculated and grading was performed using the I-III scoring system. No positive staining of p16 was observed in the normal cervical epithelium. With increasing severity of cervical intraepithelial neoplasias (CIN), the p16 expression increased progressively. Significant up-regulation of p16 was observed in carcinoma cervix. MIB-1 LI was observed to increase with increasing grades of CIN, and significant overexpression of MIB-1 was observed in carcinoma cervix. Correlation between grades of p16 and that of MIB-1 among cervical neoplasias showed an increasing p16 expression with consistently increasing MIB-1 LI in the groups of increasing severity. This pattern of overexpression of p16 and MIB-1 demonstrate their use as a diagnostic marker for cervical neoplastic lesion. Therefore, p16 and MIB-1 markers in tissue sections can be used as an adjunct to definitively diagnose preneoplastic and neoplastic lesions in the cervix.

Expression of cell cycle-regulatory proteins, MIB-1, p16, p53, and p63, in squamous cell carcinoma of conjunctiva: not associated with human papillomavirus infection

Squamous cell carcinoma (SCC), the most common primary malignant tumor of the conjunctiva, has a variable clinical presentation and immunohistochemical profile. Abundant cell cycles exist, including MIB-1 (Ki67 antigen), p16, p53, and p63, within the conjunctiva SCC. This investigation first reports the expressions of cell cycle markers in SCC. A retrospective study was conducted between December 1976 and June 2004, comprising 13 consecutive patients with conjunctiva SCC who were treated with surgical excision. Detailed clinical parameters were also reviewed. Overexpression of MIB-1, p16, p53, and p63 genes were studied by immunohistochemistry. Genechip containing 39 subtypes was used to elucidate human papillomavirus (HPV). The study group contained 13 (100%) men, with a mean age of 68+/-18 years and follow-up period of 20+/-17 months. The sample included four (33%) SCC located in the left eye and two (17%) recurrent SCC. Overexpression of the p53 and p63 was considerably higher than that of the p16 (P<0.01). HPV DNA was not detected in any of the 13 cases. This work first examined the immunohistochemical overexpression of cell cycle (MIB-1, p16, p53, and p63) in SCC. This investigation then showed that the expression of cell cycles in SCC was associated with key tumor clinicopathological features. This approach can help distinguish the potential roles of cell cycle in the development of SCC.

Correlation of Her-2/neu Gene Amplification with Other Prognostic and Predictive Factors in Female Breast Carcinoma

The purpose of this study was to determine if any relationship exists between Her-2/neu gene amplification and estrogen receptor (ER), progesterone receptor (PR), MIB-1, grade, size and age in female breast cancer. Five hundred and eighteen female patients with invasive breast carcinoma, 390 ductal and 128 lobular, in which assessment of Her-2/neu amplification by fluorescence in-situ hybridization (FISH) has been performed, were reviewed retrospectively. Each patient was further assessed for ER, PR, MIB-1, grade, size and age at diagnosis. Chi-square analysis was then used to correlate the above observations. Overall gene amplification was seen in 76 (15%) of the cases, 68 (17%) were ductal and 8 (6%) were lobular. Her-2/neu gene was amplified in 37 (10%) out of 379 ER positive cases and in 39 (28%) out of 139 ER negative cases. Her-2/neu was amplified in 22 (7%) out of 301 PR positive cases and in 54 (25%) out of 217 PR negative cases. Amplification occurred in 18 (8%) out of 222 negative MIB-1 cases and amplified in 58 (20%) out of 296 positive cases. Amplification was seen in 5 (10%) out of 49 grade I tumors, 17 (12%) out of 143 grade II tumors and 54 (27%) out of 198 grade III tumors. Lobular carcinomas were not graded. Amplification was present in 52 (15%) out of 346 T1 lesions, in 17 (13%) out of 130 T2 lesions, in 5 (17%) out of 30 T3 lesions and in 2 (17%) out of 12 T4 lesions. Her-2/neu was amplified in 67 (14%) out of 467 woman 41 years and older, and in 9 (18%) out of 51 women 40 years and younger. Comparison of these frequencies using chi-square test revealed statistically significant correlation between Her-2/neu amplification and ductal versus lobular carcinoma (p<0.0003), ER (p=0.0001) and PR (p<0.0001) negative tumors, over-expression of MIB-1 (p<0.0005) and high tumor grade (p=0.0009), while size of the tumor (p=0.08) and age of the patients (p=0.67) were not statistically significant. Correlation was found between Her-2/neu amplification and tumor type, high histological grade, ER and PR negative tumors, and high proliferative MIB-1 index. No correlation was found between size of the tumor and age of the patient with Her-2/neu amplification.

Prognostic value of EGF receptor and tumor cell proliferation in bladder cancer: therapeutic implications

Changes in growth factor receptor expression may confer a growth advantage on tumour cells. Epidermal growth factor-receptor (EGF-R) has been associated with the genesis of bladder tumours. We sought a link between EGF-R expression and MIB-1 cell proliferation and examined their prognostic value in the progression of bladder cancer. Fresh frozen samples from 113 transitional cell carcinomas (TCC) of the bladder and 10 healthy bladders were studied by immunohistochemistry, using monoclonal antibodies for EGF-R expression and MIB-1 for cell proliferation. Qualitative and quantitative immunostaining were analyzed in relation to time to progression and compared with clinical and pathologic parameters for prognostic significance in univariate and multivariate analysis (stepwise logistic regression). EGF-R stained more intensively in invasive tumours. Median nuclear over-expression of MIB-1 was 28%. Progression free survival rate estimates (log rank test) were significantly lower in patients EGF-R positive and with MIB-1 score above 28% ( P < 0.0001, P < 0.0001, respectively). Multivariate analysis indicated that MIB-1 immunostaining was the most significant independent variable and EGF-R expression had no additional prognostic value over clinical stage and grade and cell proliferation. The MIB-1 proliferation index is a stronger predictor of bladder tumour progression than is EGF-R over-expression. This marker yield significant prognostic information in addition to stage and grade and may be of value for the clinical management of superficial and invasive bladder carcinomas. The pattern of EGF-R immunostaining and its association with tumour progression makes it a candidate for antigrowth factor therapy.

Role of expression of cell cycle inhibitor p27 and MIB-1 in predicting lymph node metastasis in male breast carcinoma.

Tumor expression of the proliferation marker (MIB-1) and the cell cycle-related protein (p27) may predict the biologic behavior of various human tumors. The purpose of this study was to evaluate the role of p27 and MIB-1 expression in predicting lymph node metastasis in male breast carcinomas (MBCs). We studied 67 patients with invasive MBC who had undergone modified radical mastectomy. Pathologic lymph node status was correlated with the p27 protein and the MIB-1 proliferation index. These factors were studied immunohistologically by standard methods. Men in this study ranged from 36 to 92 years of age (mean, 63 years); 43 (64%) were T1 lesions, and 24 (36%) were T2 lesions. Twenty-nine patients (43%) had positive nodes. p27 was expressed in 43 tumors (64%) and MIB-1 in 13 tumors (19.4%). Tumors with positive p27 showed positive lymph nodes in 10 cases (23%). In contrast, p27-negative tumors had positive lymph nodes in 18 cases (75%). Tumors positive for MIB-1 show positive lymph nodes in 11 cases (85%). However, when MIB-1 was negative, only 16 patients (30%) had positive lymph nodes. Multivariate logistic regression analysis confirmed the utility of MIB-1 overexpression in predicting lymph node metastasis ( p < 0.0006). Also, decreased p27 protein expression strongly correlates with lymph node metastasis ( p < or = 0.0001). Furthermore, when p27 was negative and MIB-1 was positive, 100% of the patients had positive lymph nodes. In contrast, when p27 was positive and MIB-1 was negative, only 12% of patients had positive lymph nodes. The reduced expression of the p27 protein and the overexpression of the MIB-1 proliferation index in this study show a significant correlation in predicting lymph nodes metastasis in MBCs.

Topoisomerase IIα Expression in Breast Cancer: Correlation with Outcome Variables

Topoisomerase IIα (topo IIα) plays a key role in DNA replication and is a target for multiple chemotherapeutic agents. In breast cancer, topo II expression has been linked to cell proliferation and HER2/neu protein overexpression. However, its relationship with outcome variables is not well established.Formalin-fixed, paraffin-embedded primary breast cancers from 184 women (mean age, 60 years) were stained for topo II by automated immunohistochemistry. A topo II expression index (TI) was determined by counting the number of positive cells per high-power field and calculating an overall mean number of positive cells per high-power field. Tumors with a TI of more than 1 were considered positive, and those with a TI of 1 or less were considered negative. A cell proliferation index was determined by automated immunohistochemistry using the MIB-1 antibody in an identical technique. HER-2/neu gene amplification (HER-2 amp) was determined by automated fluorescence in situ hybridization using the Ventana unique sequence probe.Fifty-nine (32%) of the tumors had a TI greater than 1. On univariate analysis, increased topo II expression correlated with decreased patient survival (p =.001), advanced tumor stage (p =.034), lymph node metastasis (p =.018), and HER-2 amp (p =.016). Tumor stage (p <.0001), node-positive status (p <.0001), tumor grade (p =.025), HER-2 amp (p <.0001), and MIB-1 overexpression (p =.002) also correlated with survival on univariate analysis. Topo II expression did not correlate with tumor size, grade, estrogen receptor/progesterone receptor status, or disease recurrence. On multivariate analysis, stage (p <.0001), lymph node metastasis (p <.0001), and tumor grade (p =.002) all independently predicted disease-related death.Increased topo II expression is associated with an aggressive form of breast cancer featuring HER-2 amp and predicts disease-related death, lymph node metastasis, and advanced tumor stage.

Prognostic significance of p34cdc2 cyclin-dependent kinase and MIB1 overexpression, and HER-2/neu gene amplification detected by fluorescence in situ hybridization in breast cancer.

The HER-2/neu oncogene, localized to chromosome 17q, shares substantial homology with the epidermal growth factor receptor. HER-2/neu gene amplification and protein overexpression have been associated with poor prognosis in breast cancer. Formalin-fixed paraffin-embedded primary invasive breast cancer tissues from 135 women were tested for HER-2/neu gene amplification by automated fluorescence in situ hybridization (FISH) using a sequence probe. The tumors also were evaluated by immunohistochemistry for proliferation markers Ki 67 (MIB1) and p34cdc2 cyclin-dependent kinase. Patients were followed up for a mean of 61 months. There were 70 node-negative and 65 node-positive cases. Ki 67 and p34cdc2 proliferation marker overexpression, HER-2/neu oncogene amplification, large tumor size, high tumor grade, advanced tumor stage, positive lymph node status, and distant metastasis at the time of diagnosis predicted disease-related death in combined node-negative and node-positive breast cancer. HER-2/neu gene amplification, tumor stage, lymph node metastasis, tumor grade, and distant metastasis at the time of diagnosis independently predicted disease outcome. HER-2/neu amplification detected by FISH also predicted disease-related death independent of lymph node status, tumor grade, and distant metastasis in breast cancer patients who received adjuvant therapy.