RESUMO
The probiotic efficiencies of the mixed probiotics containing Lactobacillus pentosus BD6, Lac. fermentum LW2, Bacillus subtilis E20, and Saccharomyces cerevisiae P13 for shrimp growth and health status improvement were better than those when using single probiotics. The probiotic mixture at a level of 108â¯colony-forming units (cfu) (kg diet)-1 and the diets containing BD6 and E20 at 109â¯cfu (kg diet)-1 significantly improved the growth and health status of shrimp, whereas the diets containing P13 or LW2 did not significantly affect the growth of shrimp. No significant difference in the carcass composition was recorded among the control and treatments. After 56 days of feeding, shrimp fed the diet containing the probiotic mixture (107â¼109â¯cfu (kg diet)-1) had higher survival after injection with the V. alginolyticus, but 109â¯cfu (kg diet)-1 of single probiotics (except for S. cerevisiae P13) had to be administered to improve shrimp survival. The better disease resistance of shrimp in groups fed the probiotic mixture might have been due to increased phenoloxidase activity, respiratory bursts, and lysozyme activity of hemocytes. Therefore, we considered that the probiotic mixture could adequately provide probiotic efficiency for white shrimp, and a diet containing 108â¯cfu (kg diet)-1 probiotic mixture is recommended.
Assuntos
Bacillus subtilis/química , Lactobacillus/química , Penaeidae/efeitos dos fármacos , Probióticos/farmacologia , Saccharomyces cerevisiae/química , Ração Animal/análise , Animais , Dieta , Resistência à Doença , Nível de Saúde , Penaeidae/crescimento & desenvolvimento , Penaeidae/fisiologia , Probióticos/classificaçãoRESUMO
Hyaline vascular Castleman disease is traditionally regarded as a reactive hyperplastic process. Occasional cases, however, have been reported with cytogenetic anomalies bringing this concept into question. In this study, we used conventional and methylation-specific polymerase chain reaction methods to assess the human androgen receptor α (HUMARA) gene in 29 female patients with hyaline vascular Castleman disease and compared the results with three cases of plasma cell Castleman disease and 20 cases of age-matched lymphoid hyperplasia. We also assessed for immunoglobulin gene and T-cell receptor gene rearrangements, and conventional cytogenetic analysis was performed in three cases of hyaline vascular Castleman disease. In cases with informative results, conventional and methylation-specific human androgen receptor α gene analyses yielded a monoclonal pattern in 10 of 19 (53%) and 17 of 23 (74%) cases of hyaline vascular Castleman disease, respectively. A monoclonal pattern was also detected in three cases of plasma cell Castleman disease but not in cases of lymphoid hyperplasia. The frequency of monoclonality was higher for lesions >5 cm in size (100%) and for the stromal-rich variant (91%). Cytogenetic abnormalities in stromal cells were revealed in two cases of hyaline vascular Castleman disease and no cases showed monoclonal immunoglobulin or T-cell receptor gene rearrangements. Follow-up data showed persistent disease in 4 of 23 (17%) patients. We conclude that hyaline vascular Castleman disease is often a monoclonal proliferation, most likely of lymph node stromal cells.
Assuntos
Hiperplasia do Linfonodo Gigante/genética , Hiperplasia do Linfonodo Gigante/patologia , Receptores Androgênicos/genética , Cariótipo Anormal , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Aberrações Cromossômicas , Células Clonais , Feminino , Rearranjo Gênico , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Receptores de Antígenos de Linfócitos T/genética , Células Estromais/patologia , Adulto JovemRESUMO
ATM and BRCA1 are DNA repair genes that play a central role in homologous recombination repair. Alterations of ATM and BRCA1 gene expression are found in cancers, some of which are correlated with treatment response and patient outcome. However, the role of ATM and BRCA1 gene expression in head and neck cancer (HNC) is not well characterized. Here, we examined the prognostic role of ATM and BRCA1 expression in two HNC cohorts with and without betel quid (BQ) exposure. The results showed that the expression of ATM and BRCA1 was downregulated in BQ-associated HNC, as the BQ ingredient arecoline could suppress the expression of both genes. Low expression of either ATM or BRCA1 was correlated with poor overall survival (OS) and was an independent prognostic factor in multivariate analysis (ATM HR: 1.895, p = 0.041; BRCA1 HR: 2.163, p = 0.040). The combination of ATM and BRCA1 expression states further improved on the prediction of OS (HR: 4.195, p = 0.001, both low vs. both high expression). Transcriptomic analysis showed that inhibition of ATM kinase by KU55933 induced apoptosis signaling and potentiated cisplatin-induced cytotoxicity. These data unveil poor prognosis in the HNC patient subgroup with low expression of ATM and BRCA1 and support the notion of ATM-targeted therapy.
RESUMO
Diffuse large B-cell lymphoma (DLBCL) may present initially in bone marrow, liver and spleen without any lymphadenopathy (referred to as BLS-type DLBCL), which is aggressive and frequently associated with hemophagocytic syndrome. Its tumorigenesis and molecular mechanisms warrant clarification. By gene microarray profiling with bioinformatics analysis, we found higher expression of the stem cell markers HOXA9 and NANOG, as well as BMP8B, CCR6 and S100A8 in BLS-type than conventional DLBCL. We further validated expression of these markers in a large cohort of DLBCL including BLS-type cases and found that expression of HOXA9 and NANOG correlated with inferior outcome and poor prognostic parameters. Functional studies with gene-overexpressed and gene-silenced DLBCL cell lines showed that expression of NANOG and HOXA9 promoted cell viability and inhibited apoptosis through suppression of G2 arrest in vitro and enhanced tumor formation and hepatosplenic infiltration in a tail-vein-injected mouse model. Additionally, HOXA9-transfected tumor cells showed significantly increased soft-agar clonogenic ability and tumor sphere formation. Interestingly, B cells with higher CCR6 expression revealed a higher chemotactic migration for CCL20. Taken together, our findings support the concept that tumor or precursor cells of BLS-type DLBCL are attracted by chemotaxis and home to the bone marrow, where the microenvironment promotes the expression of stem cell characteristics and aggressiveness of tumor cells.
Assuntos
Linfoma Difuso de Grandes Células B/metabolismo , Linfoma Difuso de Grandes Células B/patologia , Células-Tronco/metabolismo , Animais , Ciclo Celular/genética , Ciclo Celular/fisiologia , Morte Celular/genética , Morte Celular/fisiologia , Linhagem Celular Tumoral , Biologia Computacional , Feminino , Citometria de Fluxo , Regulação Neoplásica da Expressão Gênica , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Immunoblotting , Imuno-Histoquímica , Hibridização In Situ , Camundongos , Camundongos SCID , Proteína Homeobox Nanog/genética , Proteína Homeobox Nanog/metabolismo , RNA Mensageiro/metabolismo , Células-Tronco/fisiologiaRESUMO
BACKGROUND: Effective prognostic biomarkers and powerful target-therapeutic drugs are needed for improving the treatment of Hepatocellular carcinoma (HCC). OBJECTIVE: This study aimed to evaluate the expression of FOXM1 and Aurora-A and their prognostic value in HCC. METHODS: We determined the differentially expressed genes signature in HCC using the Gene Set Enrichment Analysis (GSEA), and then evaluated the expression of FOXM1 and Aurora-A in TCGA and KMUH cohort. Associations between co-expression of FOXM1 and Aurora-A and clinical variables were calculated. Overall survival (OS) and recurrence-free survival (RFS) were estimated with different FOXM1 and Aurora-A expression status. RESULTS: FOXM1-related gene sets were mostly associated with cell cycle regulation in HCC tissues. We found a positive correlation between the expression of FOXM1 and Aurora-A. Overexpression of FOXM1 and Aurora-A was associated with larger tumor size, advanced stage, higher grade, and double-positive for HBV and HCV. The coordinated overexpression of FOXM1 and Aurora-A was the most significant independent prognostic factor for OS and RFS. Furthermore, the concomitant high expression of FOXM1 and Aurora-A predicted the worst OS of sorafenib-treated patients with HCC. CONCLUSIONS: The co-expression of FOXM1 and Aurora-A could be a reliable biomarker to predict the sorafenib response and prognosis of HCC patients.
Assuntos
Aurora Quinase A/metabolismo , Biomarcadores Tumorais/metabolismo , Carcinoma Hepatocelular/tratamento farmacológico , Proteína Forkhead Box M1/metabolismo , Neoplasias Hepáticas/tratamento farmacológico , Recidiva Local de Neoplasia/epidemiologia , Sorafenibe/farmacologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/mortalidade , Carcinoma Hepatocelular/patologia , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Conjuntos de Dados como Assunto , Intervalo Livre de Doença , Resistencia a Medicamentos Antineoplásicos , Feminino , Seguimentos , Regulação Neoplásica da Expressão Gênica , Humanos , Fígado/patologia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/genética , Prognóstico , Sorafenibe/uso terapêutico , Regulação para Cima , Adulto JovemRESUMO
Angioimmunoblastic T-cell lymphoma (AITL) carries genetic mutations of TET2, RHOA, and IDH2, but the prognostic impact of these mutations is not widely investigated. Although one study shows no difference in overall survival between patients with or without RHOA G17V mutation, a poor performance status is associated with RHOA G17V-mutated AITL, which is an independent adverse factor. We retrospectively investigated the prognostic impact of RHOA G17V mutation in AITL patients. A total of 31 cases were enrolled (male-to-female, 2.1; mean age: 62.8 years). RHOA G17V mutation was analyzed by deep sequencing. We found that in contrast to RHOA-wild type, patients with RHOA G17V-mutated AITL more frequently had B symptoms (p = .035), stronger PD1 expression (p = .045), ≥3 TFH markers (p = .011), higher blood vessel density (p<.001), and poorer progression-free survival (p = .046). These results support a role for RHOA genetic testing in AITL patients as ROHA G17V mutation carries a worse prognosis, probably associated with B symptoms and stage IV disease.
Assuntos
Linfadenopatia Imunoblástica , Linfoma de Células T , Feminino , Humanos , Linfadenopatia Imunoblástica/diagnóstico , Linfadenopatia Imunoblástica/genética , Linfoma de Células T/diagnóstico , Linfoma de Células T/genética , Masculino , Pessoa de Meia-Idade , Intervalo Livre de Progressão , Estudos Retrospectivos , Taiwan/epidemiologia , Proteína rhoA de Ligação ao GTP/genética , Proteína rhoA de Ligação ao GTP/metabolismoRESUMO
Arecoline is the principal alkaloid in the areca nut, a component of betel quids (BQs), which are carcinogenic to humans. Epidemiological studies indicate that BQ-chewing contributes to the occurrence of head and neck cancer (HNC). Previously, we have reported that arecoline (0.3 mM) is able to inhibit DNA repair in a p53-dependent pathway, but the underlying mechanism is unclear. Here we demonstrated that arecoline suppressed the expression of DDB2, which is transcriptionally regulated by p53 and is required for nucleotide excision repair (NER). Ectopic expression of DDB2 restored NER activity in arecoline-treated cells, suggesting that DDB2 downregulation was critical for arecoline-mediated NER inhibition. Mechanistically, arecoline inhibited p53-induced DDB2 promoter activity through the DNA-binding but not the transactivation domain of p53. Both NER and DDB2 promoter activities declined in the chronic arecoline-exposed cells, which were consistent with the downregulated DDB2 mRNA in BQ-associated HNC specimens, but not in those of The Cancer Genome Atlas (TCGA) cohort (no BQ exposure). Lower DDB2 mRNA expression was correlated with a poor outcome in HNC patients. These data uncover one of mechanisms underlying arecoline-mediated carcinogenicity through inhibiting p53-regulated DDB2 expression and DNA repair.
RESUMO
Fragile X syndrome (FXS) is the most frequent genetic cause of intellectual disability (ID). It was previously believed that the FXS prevalence was low in Chinese population, and the cost-efficiency of FXS carrier screening was questioned. This retrospective observational study was conducted between September 2014 and May 2017 to determine the prevalence of FXS carriers in a large Chinese cohort of pregnant women. The FMR1 CGG repeat status was determined in 20,188 pregnant Taiwanese women and we identified 26 women with premutation (PM). The PM allele was transmitted to the fetus in 17 pregnancies (56.6%), and six of 17 expanded to full mutation (FM). One asymptomatic woman had a FM allele with 280 CGG repeats. Prenatal genetic diagnosis of her first fetus revealed a male carrying a FMR1 gene deletion of 5' UTR and exon 1. Her second fetus was a female carrying a FM allele as well. This is so far the largest study of the FXS carrier screening in Chinese women. The prevalence of premutation allele for FXS in normal asymptomatic Taiwanese women was found to be as high as 0.13% (1 in 777) in this study. The empirical evidence suggests that reproductive FXS carrier screening in Taiwan might be cost-effective.
Assuntos
Etnicidade/genética , Síndrome do Cromossomo X Frágil/genética , Triagem de Portadores Genéticos/métodos , Adulto , Alelos , Análise Custo-Benefício , Feminino , Triagem de Portadores Genéticos/economia , Humanos , Gravidez , Estudos Retrospectivos , TaiwanRESUMO
Withanolides are generally defined as C(28) steroidal lactones built on an intact or rearranged ergostane skeleton and have been shown to exhibit antiproliferative activity on various types of cancer cells. In this study, we investigated the effect of a new withanolide Tubocapsanolide A isolated from Tubocapsicum anomalum and addressed its molecular action. Tubocapsanolide A inhibited proliferation of A549, H358, and H226 human lung cancer cells via induction of G(1) growth arrest. We found that Tubocapsanolide A treatment led to up-regulation of cyclin E, p21, and p27, whereas other cyclins and cyclin-dependent kinases were not affected in A549 cells. Conversely, Skp2, the F-box protein that is implicated in the mediation of degradation of p21 and p27, was significantly down-regulated. Chromatin immunoprecipitation assay suggested that Tubocapsanolide A suppressed Skp2 expression by inhibiting the binding of Rel A to the nuclear factor-kappaB site of Skp2 gene promoter. In addition, we showed that inhibition of Skp2 is a critical step for the suppression of cell proliferation by Tubocapsanolide A because ectoexpression of Skp2 effectively reversed Tubocapsanolide A-induced p27 up-regulation and growth inhibition in human lung cancer cells. Collectively, we have identified Skp2 as a molecular target for Tubocapsanolide A and suggest that this withanolide may be useful for the prevention or treatment of cancer cells with Skp2 overexpression.
Assuntos
Antineoplásicos/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Ergosterol/análogos & derivados , Regulação Neoplásica da Expressão Gênica , Neoplasias Pulmonares/tratamento farmacológico , Proteínas Quinases Associadas a Fase S/antagonistas & inibidores , Linhagem Celular Tumoral , Proliferação de Células , Relação Dose-Resposta a Droga , Humanos , Extratos Vegetais/farmacologia , Plantas Medicinais/metabolismo , Processamento de Proteína Pós-Traducional , Proteínas/química , Sais de Tetrazólio/farmacologia , Tiazóis/farmacologiaRESUMO
Heterogeneous nuclear ribonucleoprotein (hnRNP) Q1, an RNA-binding protein, has been implicated in many post-transcriptional processes, including RNA metabolism and mRNA splicing and translation. However, the role of hnRNP Q1 in tumorigenesis remains unclear. We previously performed RNA immunoprecipitation (RIP)-seq analysis to identify hnRNP Q1-interacting mRNAs and found that hnRNP Q1 targets a group of genes that are involved in mitotic regulation, including Aurora-A. Here, we demonstrate that altering the hnRNP Q1 level influences the expression of the Aurora-A protein, but not its mRNA. Stimulation with epidermal growth factor (EGF) enhances both binding between hnRNP Q1 and Aurora-A mRNA as well as the efficacy of the hnRNP Q1-induced translation of Aurora-A mRNA. The EGF/hnRNP Q1-induced translation of Aurora-A mRNA is mediated by the mTOR and ERK pathways. In addition, we show that hnRNP Q1 up-regulates the translation of a group of spindle assembly checkpoint (SAC) genes. hnRNP Q1 overexpression is positively correlated with the levels of Aurora-A and the SAC genes in human colorectal cancer tissues. In summary, our data suggest that hnRNP Q1 plays an important role in regulating the expression of a group of cell cycle-related genes. Therefore, it may contribute to tumorigenesis by up-regulating the translation of these genes in colorectal cancer.
Assuntos
Transformação Celular Neoplásica/metabolismo , Neoplasias Colorretais/metabolismo , Fator de Crescimento Epidérmico/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Sistema de Sinalização das MAP Quinases , Mitose , Proteínas de Neoplasias/metabolismo , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/patologia , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Fator de Crescimento Epidérmico/genética , Células HCT116 , Ribonucleoproteínas Nucleares Heterogêneas/genética , Humanos , Proteínas de Neoplasias/genéticaRESUMO
By using RNA-immunoprecipitation assay following next-generation sequencing, a group of cell cycle-related genes targeted by hnRNP Q1 were identified, including Aurora-A kinase. Overexpressed hnRNP Q1 can upregulate Aurora-A protein, but not alter the mRNA level, through enhancing the translational efficiency of Aurora-A mRNA, either in a cap-dependent or -independent manner, by interacting with the 5'-UTR of Aurora-A mRNA through its RNA-binding domains (RBDs) 2 and 3. By ribosomal profiling assay further confirmed the translational regulation of Aurora-A mRNA by hnRNP Q1. Overexpression of hnRNP Q1 promotes cell proliferation and tumor growth. HnRNP Q1/ΔRBD23-truncated mutant, which loses the binding ability and translational regulation of Aurora-A mRNA, has no effect on promoting tumor growth. The expression level of hnRNP Q1 is positively correlated with Aurora-A in colorectal cancer. Taken together, our data indicate that hnRNP Q1 is a novel trans-acting factor that binds to Aurora-A mRNA 5'-UTRs and regulates its translation, which increases cell proliferation and contributes to tumorigenesis in colorectal cancer.
Assuntos
Aurora Quinase A/genética , Carcinogênese/genética , Neoplasias Colorretais/genética , Ribonucleoproteínas Nucleares Heterogêneas/genética , Aurora Quinase A/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/genética , Neoplasias Colorretais/patologia , Feminino , Regulação Neoplásica da Expressão Gênica , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Humanos , Masculino , Proteínas com Motivo de Reconhecimento de RNA , RNA Mensageiro/genéticaRESUMO
Sclerosing angiomatoid nodular transformation (SANT) of the spleen is a morphologically distinctive lesion. Although the clinical course of SANT is benign, its reactive or neoplastic nature remains to be clarified. Furthermore, some investigators have suggested that SANT is related to IgG4 sclerosing lesion or inflammatory pseudotumor with stromal cells positive for Epstein-Barr virus (EBV). In this study, we assessed 22 cases of SANT derived from adult women. Clinical data and follow-up information were obtained by chart review. Immunohistochemical studies for IgG4, IgG, and CD21 stains and in situ hybridization to detect EBV-encoded small RNAs were performed. We also assessed genomic DNA extracted from paraffin-embedded tissue for human androgen-receptor α gene analysis using conventional and methylation-specific polymerase chain reaction methods. The median patient age was 41.5 years (range, 25 to 82 y). Most (77%) patients presented with a single mass that was detected incidentally (59%). The mean size of the lesions was 3.8 cm (range, 1.0 to 9.0 cm). Clinical symptoms correlated with multiple lesions (P=0.043) but not lesional size (P=0.637) or location in the spleen (hilum vs. periphery, P=0.696). None of the cases had evidence of IgG4-related disease or recurred after splenectomy. The mean number of IgG4 cells was 27.7 (range, 4 to 125), and the mean IgG4/IgG ratio was 16.4% (range, 1.6% to 55.7%) with only 2 cases being >40%. Cases with higher IgG4 cells did not correlate with inflammatory pseudotumor-like morphology. No lesions were positive for EBV-encoded small RNAs, and almost all cases with informative results (n=19) showed a polyclonal pattern. We conclude that SANT is a polyclonal, reactive lesion rather than a neoplasm.
Assuntos
Esplenopatias/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/metabolismo , Células Clonais , Metilação de DNA , Feminino , Seguimentos , Marcadores Genéticos , Humanos , Imunoglobulina G/metabolismo , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase/métodos , Receptores Androgênicos/genética , Baço/metabolismo , Baço/patologia , Esplenectomia , Esplenopatias/metabolismo , Esplenopatias/patologia , Esplenopatias/cirurgiaRESUMO
OBJECTIVES: Because Ataxia Telangiectasia Mutated (ATM)-deficient cells are hypersensitive to ionizing irradiation and DNA-damaging agents, ATM kinase inhibition is thought to enhance radiochemotherapy efficacy. In this study, we investigated the roles of autophagy and reactive oxygen species (ROS) in modulating cytotoxicity induced by suppression of ATM kinase in head and neck cancer cells. MATERIALS AND METHODS: We use KU55933 to inhibit ATM kinase activity. The cell viability was determined by MTT assays. Autophagy was examined by Western blot for LC3-II and microscopy for acidic vesicles and EGFP-LC3 punctate formation. DCF-DA staining and flow cytometry were used for analyzing ROS generation. RESULTS: we found that KU55933 reduced cell viability in several head and neck cancer cell lines. KU55933-treated cells showed increased cytoplasmic vesicles, LC3-II accumulation, and EGFP-LC3 punctate formation, indicating that autophagy was induced. KU55933 also increased ROS generation, which was required for autophagy induction because the ROS scavenger N-acetyl-L-cysteine could reduce LC3-II accumulation. KU55933-induced autophagy played a cytoprotective role against ROS-mediated cytotoxicity because autophagy inhibition by chloroquine augmented KU55933's cytotoxicity. In addition, KU55933 reduced cisplatin-resistant head and neck cancer cell viabilities, and induced LC3-II accumulation in these cells. CONCLUSION: Together, these results shed light on KU55933's therapeutic values as well as autophagy inhibitors in treating primary and cisplatin-resistant head and neck cancers.
Assuntos
Autofagia/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Neoplasias de Cabeça e Pescoço/metabolismo , Morfolinas/farmacologia , Pironas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia , Western Blotting , Proteínas de Ciclo Celular/antagonistas & inibidores , Vesículas Citoplasmáticas/efeitos dos fármacos , Vesículas Citoplasmáticas/metabolismo , Proteínas de Ligação a DNA/antagonistas & inibidores , Citometria de Fluxo , Proteínas de Fluorescência Verde/efeitos dos fármacos , Proteínas de Fluorescência Verde/metabolismo , Humanos , Microscopia , Proteínas Associadas aos Microtúbulos/efeitos dos fármacos , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Supressoras de Tumor/antagonistas & inibidoresRESUMO
One apparent feature of cancerous cells is genomic instability, which may include various types of chromosomal aberrations, such as translocation, aneuploidy, and the presence of micronuclei inside the cells. Mutagenic factors that promote the emergence of genomic instability are recognized as risk factors for the development of human malignancies. In Asia, betel quid (BQ) chewing is one of such risk factors for oral cancer. Areca nut is an essential constitute of BQ and is declared as a group I carcinogen by the International Agency for Research on Cancer. However, the molecular and cellular mechanisms regarding the carcinogenicity of areca nut are not fully explored. Here we reported that arecoline, a major alkaloid of areca nut, could arrest cells at prometaphase with large amounts of misaligned chromosomes. This prometaphase arrest was evidenced by condensed chromosome pattern, increased histone H3 phosphorylation, and accumulation of mitotic proteins, including aurora A and cyclin B(1). To investigate the molecular mechanisms accounting for arecoline-induced prometaphase arrest, we found that arecoline could stabilize mitotic spindle assembly, which led to distorted organization of mitotic spindles, misalignment of chromosomes, and up-regulation of spindle assembly checkpoint (SAC) genes. The SAC proteins BubR1 and Mps1 were differentially modified between the cells treated with arecoline and nocodazole. This together with aurora A overexpression suggested that SAC might be partly suppressed by arecoline. As a result, the arecoline-exposed cells might produce progeny that contained various chromosomal aberrations and exhibited genomic instability.