CRISPR Helps Decode the Epigenetic Mysteries of Cancer

- Physiological roles of aberrant DNA methylation in vitro and in vivo

Aging is associated with an abnormal increase of DNA methylation in human gene promoters, including in bone marrow stem cells. DNA methylation patterns are further perturbed in haematological malignancies such as acute myeloid leukaemia (AML), but the physiological significance of such epigenetic changes is unknown. Previously, Dr. Gabriella Ficz and colleagues have demonstrated that aberrant DNA methylation on the CDKN2A locus in human primary epithelial cells, which they obtained from healthy women undergoing mammoplasty, resulted in a physiological change, and that cells proliferated well beyond the Hayflick limit, exhibiting other cancer-like hallmarks.

Using epigenetic editing of human stem/progenitor cells (HSPCs), that team have now shown that p15 methylation affects haematopoiesis in vivo. Upon editing the CDKN2B (p15) promoter and ARF (p14) using dCas9-3A3L, they observed DNA methylation spreading beyond the gRNA location. They find that despite a transient delivery system, DNA methylation is maintained during myeloid differentiation in vitro, and that hypermethylation of the p15 promoter reduces gene expression. In vivo, edited human HSPCs can engraft the bone marrow of mice and targeted DNA methylation is maintained in HSPCs long term. Moreover, epigenetic changes are conserved and inherited in both myeloid and lymphoid lineages. Although the proportion of myeloid (CD33+) and lymphoid (CD19+) cells is unaffected, monocyte (CD14+) populations decreased and granulocytes (CD66b+) increased in mice engrafted with p15 hypermethylated HSPCs. Monocytes derived from p15 hypermethylated HSPCs appear to be activated and show increased inflammatory transcriptional programs. The team believes that these findings have clinical relevance, since they found p15 promoter methylation in the peripheral blood of patients with clonal haematopoiesis. The recent study shows that DNA methylation can be targeted and maintained in human HSPCs and demonstrated functional relevance of aberrant DNA methylation on the p15 locus. As such, other ageing associated aberrant DNA methylation may impact haematopoiesis in vivo.

What you will learn about in this webinar:

• Epigenetic editing in primary human cells
• Understanding aberrant DNA methylation in healthy cells
• In vivo versus in vitro consequences of epigenetic editing

Webinar Programme (CEST time zone):

• 15.00 Welcome and introduction by Karen O'Hanlon Cohrt PhD., Editor-in-chief, CRISPR Medicine News
• 15.05 Dr. Gabriella Ficz / Barts Cancer Institute, London | CRISPR Helps Decode the Epigenetic Mysteries of Cancer | Physiological roles of aberrant DNA methylation in vitro and in vivo
• 15.45 Q & A with Dr. Gabriella Ficz
• 16.00 Close by CRISPR Medicine News

Speaker | Title:

Dr. Gabriella Ficz / Barts Cancer Institute, London | CRISPR Helps Decode the Epigenetic Mysteries of Cancer | Physiological roles of aberrant DNA methylation in vitro and in vivo