Biomedical subjects

Vincent C Daniel

Publications and source records attributed to Vincent C Daniel.

2 recordsLinked to original sources

PubMed2007

A stem cell-like chromatin pattern may predispose tumor suppressor genes to DNA hypermethylation and heritable silencing.

Adult cancers may derive from stem or early progenitor cells. Epigenetic modulation of gene expression is essential for normal function of these early cells but is highly abnormal in cancers, which often show aberrant promoter CpG island hypermethylation and transcriptional silencing of tumor suppressor genes and pro-differentiation factors. We find that for such genes, both normal and malignant embryonic cells generally lack the hypermethylation of DNA found in adult cancers. In embryonic stem cells, these genes are held in a 'transcription-ready' state mediated by a 'bivalent' promoter chromatin pattern consisting of the repressive mark, histone H3 methylated at Lys27 (H3K27) by Polycomb group proteins, plus the active mark, methylated H3K4. However, embryonic carcinoma cells add two key repressive marks, dimethylated H3K9 and trimethylated H3K9, both associated with DNA hypermethylation in adult cancers. We hypothesize that cell chromatin patterns and transient silencing of these important regulatory genes in stem or progenitor cells may leave these genes vulnerable to aberrant DNA hypermethylation and heritable gene silencing during tumor initiation and progression.

Adult↗

PubMed2006

Developmental signalling pathways in lung cancer.

Hedgehog, Notch and Wnt signalling are all essential for axial patterning and progenitor cell fates in signalling pathways conserved from flies to humans. Aberrant activation of these pathways is observed in a wide variety of cancers, suggesting that these embryonic signalling pathways contribute in a fundamental way to the evolution and maintenance of a malignant phenotype. Because all three of these pathways participate in lung development, recent studies have begun to explore the connection between lung development, airway epithelial repair and lung cancer. Development, repair and malignant transformation of the neuroendocrine lineage are all accompanied by aberrant Hedgehog pathway activation, whereas Notch and Wnt signalling may be important in other airway cell types. Small molecule targeting of these pathways may provide therapeutic opportunities in lung cancer. The plant-derived alkaloid cyclopamine is a naturally occurring Hedgehog pathway inhibitor that shows therapeutic promise in small cell lung cancer, a highly aggressive neuroendocrine tumour. A more detailed understanding of how embryonic signalling pathways participate in airway epithelial repair and tumourigenesis may reveal more novel therapeutic vulnerabilities in lung cancer.

Animals↗