Expressions of STMN1, BubR1, bcl-2 and Bad in patients with esophageal squamous cell carcinoma and their relationship with chemotherapy effect of paclitaxel-containing regimen / 肿瘤研究与临床

Objective:To investigate the correlation between the expression levels of STMN1, BubR1, bcl-2 and Bad and the chemotherapy effect of paclitaxel-containing regimen in patients with esophageal squamous cell carcinoma (ESCC).Methods:The clinical data of ESCC patients who received paclitaxel-containing chemotherapy at Fenyang Hospital Affiliated to Shanxi Medical University from September 2016 to June 2021 were retrospectively analyzed. Among them, 59 cases received maintenance chemotherapy and 27 cases received surgery after 3 courses of neoadjuvant chemotherapy. The expression levels of STMN1, BubR1, bcl-2 and Bad in tumor tissues before chemotherapy were detected by immunohistochemistry. The imaging efficacy after 3 courses of chemotherapy and pathological efficacy after neoadjuvant chemotherapy were evaluated. The imaging efficacy, pathological efficacy and progression-free survival (PFS) were compared between the high expression group and the low expression group of each protein.Results:The proportion of patients with stage Ⅳ (46.3%, 19/41), the proportion of patients with low differentiation (22%, 9/41) and the incidence of lymph node metastasis (95.1%, 39/41) in STMN1 high expression group were higher than those in STMN1 low expression group (17.8%, 8/45; 4.4%, 2/45; 64.4%, 29/45), and the differences were statistically significant (all P < 0.05). The proportion of patients with stage Ⅳ in Bad high expression group was lower than that in Bad low expression group, and the difference was statistically significant ( P < 0.05). In the evaluation of imaging efficacy, the chemotherapy sensitivity rates in STMN1 and BubR1 high expression groups (29.3%, 12/41; 37.9%, 22/58) were lower than those in STMN1 and BubR1 low expression groups (75.6%, 34/45; 85.7%, 24/28), and the chemotherapy sensitivity rate of patients in Bad high expression group (65.9%, 27/41) was higher than that in Bad low expression group (42.2%, 19/45), and the difference was statistically significant (all P < 0.05). There was no statistical correlation between bcl-2 expression and chemotherapy sensitivity rate ( P > 0.05). In the evaluation of pathological efficacy, the proportion of patients with tumor regression grade (TRG) score 0-1 after neoadjuvant therapy in STMN1 high expression group (27.3%, 3/11) was lower than that in STMN1 low expression group (75.0%, 12/16), and the difference was statistically significant ( P = 0.022). There were no statistical differences in the proportions of patients with TRG score 0-1 after neoadjuvant therapy between high and low expression groups of BubR1, bcl-2 and Bad (all P > 0.05). The PFS rate was 15.2% (9/59) for patients received maintenance chemotherapy, and the median PFS time was 6 months. Kaplan-Meier analysis showed that PFS in STMN1 low expression group was better than that in STMN1 low expression group ( χ2 = 12.90, P < 0.001). PFS in BubR1 low expression group was better than that in BubR1 high expression ( χ2 =12.04, P < 0.001). PFS in Bad high expression group was better than that in Bad low expression group ( χ2 =9.69, P = 0.004). There was no statistical difference in PFS between high and low bcl-2 expression groups ( χ2 =1.43, P = 0.320). Conclusions:ESCC patients with low expression of STMN1, low expression of BubR1 and high expression of Bad have better chemotherapy effect after receiving paclitaxel-containing regimen, but there is no correlation between bcl-2 expression and chemotherapy efficacy.

MCC1019, a selective inhibitor of the Polo-box domain of Polo-like kinase 1 as novel, potent anticancer candidate

Polo-like kinase (PLK1) has been identified as a potential target for cancer treatment. Although a number of small molecules have been investigated as PLK1 inhibitors, many of which showed limited selectivity. PLK1 harbors a regulatory domain, the Polo box domain (PBD), which has a key regulatory function for kinase activity and substrate recognition. We report on 3-bromomethyl-benzofuran-2-carboxylic acid ethyl ester (designated: MCC1019) as selective PLK1 inhibitor targeting PLK1 PBD. Cytotoxicity and fluorescence polarization-based screening were applied to a library of 1162 drug-like compounds to identify potential inhibitors of PLK1 PBD. The activity of compound MC1019 against the PLK1 PBD was confirmed using fluorescence polarization and microscale thermophoresis. This compound exerted specificity towards PLK1 over PLK2 and PLK3. MCC1019 showed cytotoxic activity in a panel of different cancer cell lines. Mechanistic investigations in A549 lung adenocarcinoma cells revealed that MCC1019 induced cell growth inhibition through inactivation of AKT signaling pathway, it also induced prolonged mitotic arrest-a phenomenon known as mitotic catastrophe, which is followed by immediate cell death apoptosis and necroptosis. MCC1019 significantly inhibited tumor growth in a murine lung cancer model without affecting body weight or vital organ size, and reduced the growth of metastatic lesions in the lung. We propose MCC1019 as promising anti-cancer drug candidate.

BubR1 Insufficiency Impairs Affective Behavior and Memory Function in Mice / 대한배뇨장애요실금학회지

PURPOSE: Although aging causes functional declines in cognition, the molecular mechanism underlying these declines remains largely unknown. Recently, the spindle checkpoint kinase budding uninhibited by benzimidazole-related 1 (BubR1) has emerged as a key determinant for age-related pathology in various tissues including brain. However, the neurobehavioral impact of BubR1 has not been explored. In this study, we investigated the role of BubR1 in behavioral function. METHODS: To investigate the neurobiological functions of BubR1 in vivo, we utilized transgenic mice harboring BubR1 hypomorphic alleles (BubR1 H/H mice), which produce low amounts of BubR1 protein, as well as mice that have specific knockdown of BubR1 in the adult dentate gyrus. To assess anxiety-like behavior, the above groups were subjected to the elevated plus maze and the light-dark test, in addition to utilizing the tail-suspension and forced-swim test to determine depression-like behavior. We used novel object recognition to test for memory-related function. RESULTS: We found that BubR1 H/H mice display several behavioral deficits when compared to wild-type littermates, including increased anxiety in the elevated-plus maze test, depression-like behavior in the tail suspension test, as well as impaired memory function in the novel object recognition test. Similar to BubR1 H/H mice, knockdown of BubR1 within the adult dentate gyrus led to increased anxiety-like behavior as well as depression-like behavior, and impaired memory function. CONCLUSIONS: Our study demonstrates a requirement of BubR1 in maintaining proper affective and memory-related behavioral function. These results suggest that a decline in BubR1 levels with advanced age may be a crucial contributor to age-related hippocampal dysfunction.

Crystal structure of a PP2A B56-BubR1 complex and its implications for PP2A substrate recruitment and localization

Protein phosphatase 2A (PP2A) accounts for the majority of total Ser/Thr phosphatase activities in most cell types and regulates many biological processes. PP2A holoenzymes contain a scaffold A subunit, a catalytic C subunit, and one of the regulatory/targeting B subunits. How the B subunit controls PP2A localization and substrate specificity, which is a crucial aspect of PP2A regulation, remains poorly understood. The kinetochore is a critical site for PP2A functioning, where PP2A orchestrates chromosome segregation through its interactions with BubR1. The PP2A-BubR1 interaction plays important roles in both spindle checkpoint silencing and stable microtubule-kinetochore attachment. Here we present the crystal structure of a PP2A B56-BubR1 complex, which demonstrates that a conserved BubR1 LxxIxE motif binds to the concave side of the B56 pseudo-HEAT repeats. The BubR1 motif binds to a groove formed between B56 HEAT repeats 3 and 4, which is quite distant from the B56 binding surface for PP2A catalytic C subunit and thus is unlikely to affect PP2A activity. In addition, the BubR1 binding site on B56 is far from the B56 binding site of shugoshin, another kinetochore PP2A-binding protein, and thus BubR1 and shugoshin can potentially interact with PP2A-B56 simultaneously. Our structural and biochemical analysis indicates that other proteins with the LxxIxE motif may also bind to the same PP2A B56 surface. Thus, our structure of the PP2A B56-BubR1 complex provides important insights into how the B56 subunit directs the recruitment of PP2A to specific targets.

Effect of 5-Aminosalicylic Acid on Cell Proliferation,Apoptosis and Cell Cycle in Human Colon Cancer Cell Line HT-29 / 胃肠病学

Background:Ulcerative colitis-associated colorectal cancer(UcCRC)is the most serious complication of ulcerative colitis(UC). 5-Aminosalicylic acid(5-ASA)could reduce the risk of UC progressing to UcCRC. Aims:To investigate the effect of 5-ASA on cell proliferation,apoptosis and cell cycle in human colon cancer cell line HT-29 for verifying the inhibitory effect of 5-ASA on UcCRC. Methods:HT-29 cells were treated with different concentrations(0,10,20,30, 40 mmol/ L)of 5-ASA. Cell proliferation was measured by CCK-8 assay. Cell apoptosis was determined by TUNEL method. Cell cycle was analyzed by flow cytometry. Expressions of cell mitotic regulators AuroraB and BubR1 were determined by immunohistochemistry. Results:Proliferation inhibition rates and apoptosis rates of HT-29 cells in 5-ASA 10,20,30,40 mmol/ L groups were increased with increase in concentration of 5-ASA(P ﹤ 0. 05). Proportions of cells in phase G0 / G1 in 5-ASA 30,40 mmol/ L groups were significantly lower than those in 5-ASA 0,10,20 mmol/ L groups (P ﹤ 0. 05);proportions of cells in phase S in 5-ASA 0,10,20,30 mmol/ L groups were significantly lower than that in 5-ASA 40 mmol/ L group(P ﹤ 0. 05);while proportions of cells in phase G2 / M in 5-ASA 30,40 mmol/ L groups were significantly higher than those in 5-ASA 0,10,20 mmol/ L groups(P ﹤ 0. 05). Mean optical density(MOD)values of AuroraB and BubR1 were decreased with increase in concentration of 5-ASA(P ﹤ 0. 05). Concentration of 5-ASA was positively correlated with proliferation inhibition rate and apoptosis rate of HT-29 cells(P ﹤ 0. 05),but was negatively correlated with MOD values of AuroraB and BubR1( P ﹤ 0. 05). MOD values of AuroraB and BubR1 were negatively correlated with proliferation inhibition rate and apoptosis rate of HT-29 cells as well as proportion of cells in phase G2/ M (P ﹤0. 05),but were positively correlated with proportion of cells in phase G0/ G1(P ﹤0. 05). MOD value of AuroraB was positively correlated with MOD value of BubR1(P ﹤ 0. 05). Conclusions:5-ASA can inhibit proliferation and induce apoptosis in HT-29 cells,the mechanism may be related to inhibiting expressions of AuroraB and BubR1 and the resulted effect on cell cycle.

Cross-talk between BubR1 expression and the commitment to differentiate in adipose-derived mesenchymal stem cells

BubR1 mitotic checkpoint kinase monitors attachment of microtubules to kinetochores and links regulation of the chromosome-spindle attachment to mitotic checkpoint signaling. Defects in BubR1-mediated signaling severely perturb checkpoint control and are linked to diseases such as cancer. Studies using BubR1 mouse models suggest that BubR1 activities prevent premature aging and infertility. In this study, we show that BubR1 depletion in human adipose-derived mesenchymal stem cells (ASCs) precedes loss of the differentiation potential and induction of replicative senescence. These effects occur independently of p16(INK4A) expression and may involve DNA methylation. Our results reveal a new and unsuspected feature of BubR1 expression in regulation of adult stem cell differentiation.

Correlation between over expression of BUBR1 and chromosomal instability in colorectal carcinoma / 现代生物医学进展

Objective:Over expression of BUBR1 protein was reported in several human malignancies,however whether BUBR1 plays a role in chromosomal instability phenotype remains in controversy.This study was to explore the roll of BUBR1 protein in CIN phenotype in CRC.Methods:BUBR1 expression was studied immunohistochemieally in a panel of 93 advanced sporadic eolorectal cancers.Microsatellite status was evaluated by high resolution microsatellite analysis assay,TP53 gene mutation by direct sequencing and DNA ploidy by laser scanning cytometery.The relationship between BUBR1 overexpression and TP53 gene mutation,mierosatellite status,and DNA ploidy were studied.Results:BUBR1 overexpression was confirmed in 69% of cases.The overexpression was more frequent in tumor without high frequency microsatellite instability (P＜0.01) and TP53 mutation (P＜0.05).There was no statistic correlation between DNA aneuploidy and BUBR1 overexpression; however,a tendency that aneuploidy tumors had higher percentage of BUBR1 overexpression was shown.BUBR1 overexpression was not statistically related with clinieopathological factors.Conclusion:The linkage between BUBR1 overexpression and molecular factors indicating a CIN background implied that BUBR1 overexpression was indeed related with chromosomal instability in colorectal cancer.

Correlation between over expression of BUBR1 and chromosomal instability in colorectal carcinoma / 现代生物医学进展

Objective:Over expression of BUBR1 protein was reported in several human malignancies,however whether BUBR1 plays a role in chromosomal instability phenotype remains in controversy.This study was to explore the roll of BUBR1 protein in CIN phenotype in CRC.Methods:BUBR1 expression was studied immunohistochemieally in a panel of 93 advanced sporadic eolorectal cancers.Microsatellite status was evaluated by high resolution microsatellite analysis assay,TP53 gene mutation by direct sequencing and DNA ploidy by laser scanning cytometery.The relationship between BUBR1 overexpression and TP53 gene mutation,mierosatellite status,and DNA ploidy were studied.Results:BUBR1 overexpression was confirmed in 69% of cases.The overexpression was more frequent in tumor without high frequency microsatellite instability (P＜0.01) and TP53 mutation (P＜0.05).There was no statistic correlation between DNA aneuploidy and BUBR1 overexpression; however,a tendency that aneuploidy tumors had higher percentage of BUBR1 overexpression was shown.BUBR1 overexpression was not statistically related with clinieopathological factors.Conclusion:The linkage between BUBR1 overexpression and molecular factors indicating a CIN background implied that BUBR1 overexpression was indeed related with chromosomal instability in colorectal cancer.

Correlation between over expression of BUBR1 and chromosomal instability in colorectal carcinoma / 现代生物医学进展

Objective:Over expression of BUBR1 protein was reported in several human malignancies,however whether BUBR1 plays a role in chromosomal instability phenotype remains in controversy.This study was to explore the roll of BUBR1 protein in CIN phenotype in CRC.Methods:BUBR1 expression was studied immunohistochemieally in a panel of 93 advanced sporadic eolorectal cancers.Microsatellite status was evaluated by high resolution microsatellite analysis assay,TP53 gene mutation by direct sequencing and DNA ploidy by laser scanning cytometery.The relationship between BUBR1 overexpression and TP53 gene mutation,mierosatellite status,and DNA ploidy were studied.Results:BUBR1 overexpression was confirmed in 69% of cases.The overexpression was more frequent in tumor without high frequency microsatellite instability (P＜0.01) and TP53 mutation (P＜0.05).There was no statistic correlation between DNA aneuploidy and BUBR1 overexpression; however,a tendency that aneuploidy tumors had higher percentage of BUBR1 overexpression was shown.BUBR1 overexpression was not statistically related with clinieopathological factors.Conclusion:The linkage between BUBR1 overexpression and molecular factors indicating a CIN background implied that BUBR1 overexpression was indeed related with chromosomal instability in colorectal cancer.