Biomedical subjects

Xiaoming Ju

Publications and source records attributed to Xiaoming Ju.

5 recordsLinked to original sources

PubMed2006

Cyclin D1 induction of cellular migration requires p27(KIP1).

The cyclin D1 gene is amplified and overexpressed in human breast cancer, functioning as a collaborative oncogene. As the regulatory subunit of a holoenzyme phosphorylating Rb, cyclin D1 promotes cell cycle progression and a noncatalytic function has been described to sequester the cyclin-dependent kinase inhibitor protein p27. Cyclin D1 overexpression correlates with tumor metastasis and cyclin D1-deficient fibroblasts are defective in migration. The genetic mechanism by which cyclin D1 promotes migration and movement is poorly understood. Herein, cyclin D1 promoted cellular migration and cytokinesis of mammary epithelial cells. Cyclin D1 enhanced cellular migratory velocity. The induction of migration by cyclin D1 was abolished by mutation of K112 or deletion of NH(2)-terminal residues 46 to 90. These mutations of cyclin D1 abrogated physical interaction with p27(KIP1). Cyclin D1(-/-) cells were p27(KIP1) deficient and the defect in migration was rescued by p27(KIP1) reintroduction. Conversely, the cyclin D1 rescue of cyclin D1(-/-) cellular migration was reversed by p27(KIP1) small interfering RNA. Cyclin D1 regulated p27(KIP1) abundance at the posttranslational level, inhibiting the Skp2 promoter, Skp2 abundance, and induced p27(KIP1) phosphorylation at Ser(10). Together, these studies show cyclin D1 promotes mammary epithelial cell migration. p27(KIP1) is required for cyclin D1-mediated cellular migration.

Actins↗

PubMed2006

Cyclin D1 determines mitochondrial function in vivo.

The cyclin D1 gene encodes a regulatory subunit of the holoenzyme that phosphorylates and inactivates the pRb tumor suppressor to promote nuclear DNA synthesis. cyclin D1 is overexpressed in human breast cancers and is sufficient for the development of murine mammary tumors. Herein, cyclin D1 is shown to perform a novel function, inhibiting mitochondrial function and size. Mitochondrial activity was enhanced by genetic deletion or antisense or small interfering RNA to cyclin D1. Global gene expression profiling and functional analysis of mammary epithelial cell-targeted cyclin D1 antisense transgenics demonstrated that cyclin D1 inhibits mitochondrial activity and aerobic glycolysis in vivo. Reciprocal regulation of these genes was observed in cyclin D1-induced mammary tumors. Cyclin D1 thus integrates nuclear DNA synthesis and mitochondrial function.

Animals↗

PubMed2006

Cyclin D1 regulates cellular migration through the inhibition of thrombospondin 1 and ROCK signaling.

Cyclin D1 is overexpressed in human tumors, correlating with cellular metastasis, and is induced by activating Rho GTPases. Herein, cyclin D1-deficient mouse embryo fibroblasts (MEFs) exhibited increased adhesion and decreased motility compared with wild-type MEFs. Retroviral transduction of cyclin D1 reversed these phenotypes. Mutational analysis of cyclin D1 demonstrated that its effects on cellular adhesion and migration were independent of the pRb and p160 coactivator binding domains. Genomewide expression arrays identified a subset of genes regulated by cyclin D1, including Rho-activated kinase II (ROCKII) and thrombospondin 1 (TSP-1). cyclin D1(-/-) cells showed increased Rho GTP and ROCKII activity and signaling, with increased phosphorylation of LIM kinase, cofilin (Ser3), and myosin light chain 2 (Thr18/Ser19). Cyclin D1 repressed ROCKII and TSP-1 expression, and the migratory defect of cyclin D1(-/-) cells was reversed by ROCK inhibition or TSP-1 immunoneutralizing antibodies. cyclin E knockin to the cyclin D1(-/-) MEFs rescued the DNA synthesis defect of cyclin D1(-/-) MEFs but did not rescue either the migration defect or the abundance of ROCKII. Cyclin D1 promotes cellular motility through inhibiting ROCK signaling and repressing the metastasis suppressor TSP-1.

Animals↗

PubMed2003

[Role of tissue factor in the invasive ability of cultured human colon carcinoma cells].

OBJECTIVE: To analyze the role of tissue factor (TF) in the in vitro invasive ability of human colon carcinoma cells (HT-29). METHODS: The eukaryotic expression vectors pcDNA3.1/Zeo bearing either sense or antisense TFcDNA were transfected into HT-29 cells by the way of lipofactamine 2000. TF proteins in transfected cells were detected by Western blot. In vitro Matrigel invasion assays were used to show the invasive ability of HT-29 cells with sense/antisense TFcDNA transfection. RESULTS: HT-29 cells with sense-TFcDNA transfection showed increased TF expression and invasive ability compared with the cells without transfection, but HT-29 cells with antisense-TFcDNA transfection got the contrary change. CONCLUSION: TF can increase the invasive ability of HT-29 cells in vitro.

Colonic Neoplasms↗

PubMed2002

Relationship between tissue factor expression and hepatic metastasis and prognosis in rectal cancer.

OBJECTIVE: To investigate the correlation between tissue factor (TF) expression and hepatic metastasis and prognosis in rectal cancer. METHODS: TF expression was retrospectively studied by immunohistochemical method in specimens of 40 rectal cancer, 3 hepatic metastasis and 6 benign adenoma with relation to their clinicopathologic data. RESULTS: 1. TF expression was detected in 20 (50%) of the 40 primary rectal cancer specimens and all the 3 hepatic metastatic specimens, but not in the 6 benign adenoma or normal mucosa of rectum, 2. Significant correlation was observed between TF expression and synchronic hepatic metastasis (P = 0.002) and heterochronic hepatic metastasis (P = 0.001) and 3. TF was a risk factor for the prognosis of primary rectal cancer (P = 0.024). CONCLUSION: Tissue factor expression may play a role in the process of developing hepatic metastasis. It may be considered as a new clinical indicator for monitor of hepatic metastasis and prognosis of primary rectal cancer.

Adenoma↗