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Rachel H Giles

Publications and source records attributed to Rachel H Giles.

7 recordsLinked to original sources
PubMed2006

Progenitor marker CD133 mRNA is elevated in peripheral blood of cancer patients with bone metastases.

PURPOSE: We examined whether RNA expression of CD133, a surface molecule expressed on progenitors from hematopoietic and endothelial lineages, and CD146, a pan-endothelial marker, are increased in the blood of cancer patients and whether these factors correlate with patient characteristics and are predictive factors of survival. EXPERIMENTAL DESIGN: We developed a real-time quantification method (nuclear acid sequence-based amplification) to determine expression of CD146 and CD133 mRNA in the peripheral blood mononuclear cells of 131 progressive cancer patients, 37 healthy volunteers, and 5 patients who received granulocyte colony-stimulating factor. Overall survival and other clinicopathologic variables were obtained. Cox proportional hazards studies were done. RESULTS: We show that patients with metastatic disease have a significant increase in CD133 mRNA (P = 0.03), specifically patients with bone metastasis (P < 0.001). Cancer patients with high CD133 mRNA expression, using a defined cutoff value, show a decreased survival compared with patients with low or undetectable CD133 expression (21% versus 45% cumulative survival, respectively, after 20 months; P = 0.01). Among patients with metastasis to the bone, cumulative survival was 22%, compared with 61% for patients with high or low CD133 levels (P = 0.004). Multivariate analysis showed that CD133 expression is an independent predictor for overall survival in patients with bone metastases. CD146 mRNA was not increased in patients with cancer, nor did it correlate with clinical variables or survival. CONCLUSION: CD133, but not CD146, mRNA expression is increased in cancer patients with metastatic disease, specifically with bone metastasis. In addition, CD133 mRNA expression seems to be an independent prognostic factor for overall survival.

AC133 Antigen↗
PubMed2005

Tumor suppression by the von Hippel-Lindau protein requires phosphorylation of the acidic domain.

The tumor suppressor function of the von Hippel-Lindau protein (pVHL) has previously been linked to its role in regulating hypoxia-inducible factor levels. However, VHL gene mutations suggest a hypoxia-inducible factor-independent function for the N-terminal acidic domain in tumor suppression. Here, we report that phosphorylation of the N-terminal acidic domain of pVHL by casein kinase-2 is essential for its tumor suppressor function. This post-translational modification did not affect the levels of hypoxia-inducible factor; however, it did change the binding of pVHL to another known binding partner, fibronectin. Cells expressing phospho-defective mutants caused improper fibronectin matrix deposition and demonstrated retarded tumor formation in mice. We propose that phosphorylation of the acidic domain plays a role in the regulation of proper fibronectin matrix deposition and that this may be relevant for the development of VHL-associated malignancies.

Animals↗
PubMed2004

The von Hippel-Lindau tumor suppressor protein influences microtubule dynamics at the cell periphery.

The von Hippel-Lindau (VHL) protein protects microtubules (MTs) from destabilization by nocodazole treatment. Based on this fixed-cell assay with static end points, VHL has been reported to directly stabilize the MT cytoskeleton. To investigate the dynamic changes in MTs induced by VHL in living cells, we measured the influence of VHL on tubulin turnover using fluorescence recovery after photobleaching (FRAP). To this end, we engineered VHL-deficient renal cell carcinoma cells to constitutively incorporate fluorescently labeled tubulin and to inducibly express VHL. Induction of VHL in these cells resulted in a decrease of tubulin turnover as measured by FRAP at the cell periphery, while minimally influencing MT dynamics around the centrosome. Our data indicates that VHL changes the behavior of MTs dependent on their subcellular localization implying a role for VHL in cellular processes such as migration, polarization, and cell-cell interactions. Here we propose a complementary method to directly measure VHL-induced subcellular changes in microtubule dynamics, which may serve as a tool to study the effect of MT binding proteins such as VHL.

Carcinoma, Renal Cell↗
PubMed2004

Fibronectin is a hypoxia-independent target of the tumor suppressor VHL.

The von Hippel-Lindau (VHL) tumor suppressor gene regulates the extracellular matrix by controlling fibronectin deposition. To identify novel VHL target genes, we subjected mRNA from VHL-deficient RCC cells (786-0-pRC) and a transfectant re-expressing wildtype VHL (786-0-VHL) to differential expression profiling. Among the differentially expressed genes, we detected that fibronectin is upregulated in the presence of VHL, while it is not affected by hypoxia. Thus regulation of fibronectin deposition by VHL occurs at the transcriptional level, irrespective of oxygen levels.

Carcinoma, Renal Cell↗
PubMed2003

Caught up in a Wnt storm: Wnt signaling in cancer.

The Wnt signaling pathway, named for its most upstream ligands, the Wnts, is involved in various differentiation events during embryonic development and leads to tumor formation when aberrantly activated. Molecular studies have pinpointed activating mutations of the Wnt signaling pathway as the cause of approximately 90% of colorectal cancer (CRC), and somewhat less frequently in cancers at other sites, such as hepatocellular carcinoma (HCC). Ironically, Wnts themselves are only rarely involved in the activation of the pathway during carcinogenesis. Mutations mimicking Wnt stimulation-generally inactivating APC mutations or activating beta-catenin mutations-result in nuclear accumulation of beta-catenin which subsequently complexes with T-cell factor/lymphoid enhancing factor (TCF/LEF) transcription factors to activate gene transcription. Recent data identifying target genes has revealed a genetic program regulated by beta-catenin/TCF controlling the transcription of a suite of genes promoting cellular proliferation and repressing differentiation during embryogenesis, carcinogenesis, and in the post-embryonic regulation of cell positioning in the intestinal crypts. This review considers the spectra of tumors arising from active Wnt signaling and attempts to place perspective on recent data that begin to elucidate the mechanisms prompting uncontrolled cell growth following induction of Wnt signaling.

Animals↗