Chiara Colombi

Epigenetic regulation of nuclear PI-PLCbeta1 signaling pathway in low-risk MDS patients during azacitidine treatment

Phosphoinositide-phospholipase C (PI-PLC) beta1 can be considered a specific target for demethylating therapy in high-risk myelodysplastic syndrome (MDS) patients, as azacitidine treatment has been associated with a PI-PLCbeta1-specific promoter demethylation, and induction of PI-PLCbeta1 gene and protein expression. However, little is known about the molecular effect of azacitidine in low-risk MDS or the functional mechanisms linked with azacitidine effect on PI-PLCbeta1 promoter. In the present study, we further investigated the role of epigenetic regulation of PI-PLCbeta1, mainly focusing on the structure of the PI-PLCbeta1 promoter. We first examined the effect of azacitidine on PI-PLCbeta1 promoter methylation and gene expression in low-risk MDS. Moreover, we studied the expression of key molecules associated with the nuclear inositide signaling pathways, such as cyclin D3. By applying a chromatin immunoprecipitation method, we also studied the correlation between the demethylating effect of azacitidine and the degree of recruitment to PI-PLCbeta1 promoter of some transcription factors implicated in hematopoietic stem cell proliferation and differentiation, as well as of the methyl-CpG-binding domain proteins, which specifically interact with methylated DNA. Taken together, our results hint at a specific involvement of PI-PLCbeta1 in epigenetic mechanisms, and are particularly consistent with the hypothesis of a role for PI-PLCbeta1 in azacitidine-induced myeloid differentiation.

A simple prognostic scoring system for newly diagnosed cytogenetically normal acute myeloid leukemia: retrospective analysis of 530 patients

Abstract We retrospectively analyzed the data of 337 patients with cytogenetically normal (CN) acute myeloid leukemia (AML), aged ≤ 65 years (training set). A prognostic index score (PIS) was calculated by totaling the score derived from the regression coefficients of each clinical variable, significantly associated with prognosis by multivariate analysis. The variables that were independent prognostic factors for event-free survival (EFS) and overall survival (OS) in the training set were: age ≥ 50 years, secondary AML and white blood cell count (WBC) ≥ 20 × 109/L. The patients of the training set were stratified into three groups: low-, intermediate- and high-risk. The median EFS was 25, 12 and 7 months in the low-, intermediate- and high-risk groups (p < 0.0001), respectively. The median OS was not reached in the low-risk group and was 19 and 10 months in the intermediate- and high-risk groups (p < 0.0001). This PIS was validated in a series of 193 patients with CN-AML. The median EFS was 66, 16, and 3 months (p < 0.0001) and the median OS was 66, 16, and 5 months in the three risk groups, respectively (p < 0.0001). This PIS may be useful for clinical decision-making in CN-AML and may be prospectively integrated with the newest biological markers which at present are not routinely assessed and need prognostic validation.