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This article is from Molecular Cancer , volume 13 . Abstract It is well known that the activation of Aurora A/B (Aur A/B) or inactivation of BRCA1/2 induces tumor formation. Others and we have reported that the mutual suppression between Aur A/B and BRCA1/2 may manipulate cancer cell growth and tumorigenesis, however, the interactive regulation and mechanism between these molecules are still elusive. In this study, by consecutive silencing of Aur A/B or/and BRCA1/2 with specific shRNAs, we showed that, in BRCA2-deficient pancreatic cancer cell line Capan-1 and in ovarian cancer cell line OVCA433, Aur A/B and BRCA1/2 inversely regulated the expression of each other likely through proteasome-mediated proteolysis but not through gene transcription. Aur A/B and BRCA1/2 conversely regulated cell cycle progression mainly through control of p53 and cyclin A. Moreover, the disruption of Aur A/B blocked abnormal cytokinesis and decreased cell multinuclearity and chromosome tetraploidy, whereas the deprivation of BRCA1/2 promoted the abnormal cytokinesis and enhanced the cell multinuclearity and tetraploidy. Furthermore, we showed by animal assays that the depletion of Aur A/B inhibited tumor growth of both cell lines, while the knockdown of BRCA1/2 promoted the tumor growth. However, the concurrent silencing of Aur A/B and BRCA1/2 diminished the effects of these molecules on the regulation of cell cycle, cytokinesis, and tetraploidy, leading to the burdened tumor sizes similar to those induced by scrambled shRNA-treated control cells. In summary, our study revealed that the negative interplay between Aur A/B and BRCA1/2 inversely controls the cell proliferation, cell cycle progression, cell multinuclearity, and tetraploidization to modulate tumorigenesis.

This article is from International Journal of Molecular Sciences , volume 14 . Abstract (−)-Epigallocatechin gallate (EGCG) and curcumin are two naturally derived agents that have been widely investigated worldwide. They exhibit their anti-tumor effects in many types of cancers. In the current study, the effect of the combination of the two agents on non-small cell lung cancer (NSCLC) cells was investigated. The results revealed that at low concentrations, the combination of the EGCG and curcumin strongly enhanced cell cycle arrest. Flow cytometry analysis showed that the cells were arrested at G1 and S/G2 phases. Two main cell cycle related proteins cyclin D1 and cyclin B1 were significantly inhibited at the present of EGCG and curcumin. EdU (5-ethynyl-2′-deoxyuridine) fluorescence staining showed that the DNA replication was significantly blocked. A clonal growth assay also confirmed a marked repression of cell growth. In a lung cancer xenograft node mice model, combination of EGCG and curcumin exhibited protective effect against weight loss due to tumor burden. Tumor growth was strongly repressed by the combination of the two agents, without causing any serious side-effect. Overall, these results strongly suggest that EGCG in combination with curcumin could be a candidate for chemoprevention agent of NSCLC.

This article is from Journal of Experimental & Clinical Cancer Research : CR , volume 31 . Abstract Background: Iodine 125 (125I) seed irradiation can be used as an important supplementary treatment for unresectable advanced gastric cancer. Here, we aim to comprehensively elucidate the biological effects induced by 125I seed irradiation in human gastric cancer xenograft model by using global expression and DNA methylation analyses. Methods: The 48 mice bearing NCI-N87 gastric cancer xenografts were randomly separated into 2 groups: sham seeds (O mCi) were implanted into the control group (n = 24); 125 l seeds (0.9 mCi) were implanted into the treatment group (n = 24). The mitotic index and apoptotic index were evaluated by quantitative morphometric analysis of the expression of proliferating cell nuclear antigen (PCNA) and in situ terminal transferase-mediated fluorescein deoxy- UTP nick end labeling (TUNEL), respectively. Global gene expression changes induced by 125I seed irradiation were analyzed by using Nimblegen Human gene expression array. DNA methylation profile in the tumors from control group was investigated with methylated DNA immunoprecipitation (MeDIP) and Nimblegen CpG promoter microarrays. The changes in the methylation status of selected genes were further investigated by using MeDIP-PCR. Results: 125I seed irradiation suppresses the growth of gastric cancer xenografts in nude mice. PCNA staining and tissue TUNEL assays showed that both inhibition of cell proliferation and induction of apoptosis contribute to the 125I-induced tumor suppression in nude mouse model. Gene expression profiles revealed that the expression levels of several hundred genes, many of which are associated with apoptosis or cell cycle arrest, including BMF, MAPK8, BNIP3, RFWD3, CDKN2B and WNT9A, were upregulated following 125I seed irradiation. Furthermore, the up-regulation of some of these genes, such as BNIP3 and WNT9A, was found to be associated with irradiation-induced DNA demethylation. Conclusions: This study revealed that 125I seed irradiation could significantly induce the up-regulation of apoptosis- and cell cycle-related genes in human gastric cancer xenografts. And some of the up-regulation might be attributed to 125I-irradiation induced demethylation in gene promoter regions. Collectively, these findings provided evidence for the efficacy of this modality for the treatment of gastric cancer.