Project description:Intraclonal subpopulations of circulating chronic lymphocytic leukemia (CLL) cells with different proliferative histories and reciprocal surface expression of CXCR4 and CD5 have been observed in the peripheral blood of CLL patients and named proliferative (PF), intermediate (IF) and resting (RF) cellular fractions. Transcriptional differences between paired intraclonal fractions confirmed their proliferative experience and further supported a linear advancement from PF to RF in the peripheral blood. Marked expression differences in intraclonal fractions suggest potential pathological and therapeutic relevance of studying intraclonal CLL fractions as compared to bulk cells.
Project description:Little is known about the extent of intraclonal heterogeneity of CLL tumor cells. We performed longitudinal whole genome analysis in 22 CLL cases with evidence of clinical progression and/or clinical relapse post therapy. We demonstrate the striking and unanticipated presence of genetic clonal heterogeneity, with at least 27% of patients exhibiting clonal evolution and 18% showing evidence of multiple subclones. We show that CLL progression can occur with multiple genetic subclones evolving either in a linear or branching manner. The analysis reveals a shift in the relative dominance of subclones with the emergence of initially minor clones after therapy all of which were very resistant to secondary therapies. This study uncovers the clinical importance of tracking subclone diversity in CLL.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Intraclonal subpopulations of circulating chronic lymphocytic leukemia (CLL) cells with different proliferative histories and reciprocal surface expression of CXCR4 and CD5 have been observed in the peripheral blood of CLL patients and named proliferative (PF), intermediate (IF) and resting (RF) cellular fractions. Here we found that these intraclonal circulating fractions share persistent DNA methylation signatures largely associated with the mutation status of the immunoglobulin heavy chain locus (IGHV) and their origins from distinct stages of differentiation of antigen-experienced B-cells. Increased leukemic birth rate (BR), however, showed a very limited impact on DNA methylation of circulating CLL fractions independent of IGHV mutation status. Additionally, DNA methylation heterogeneity increased as leukemic cells advanced from PF to RF in the peripheral blood. This frequently co-occurred with heterochromatin hypomethylation and hypermethylation of Polycomb-repressed regions in the PF, suggesting accumulation of longevity-associated epigenetic features in recently born cells.
