Leukemia Stem Cell Identification via ALDH Activity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current therapies for acute myeloid leukemia (AML) fail to adequately target leukemia stem cells (LSCs), leading to relapse, as existing methods to identify and quantify LSCs are cumbersome, non-quantitative, and lack clear clinical implications, making it difficult to predict relapse and deliver appropriate treatment.
Innovation Solution
A method involving the isolation and measurement of CD34+CD38− mononuclear cells with intermediate ALDH activity (CD34+CD38−ALDHint) to identify leukemic stem cells, which involves obtaining biological samples, isolating these cells, measuring ALDH activity, and determining their presence to predict relapse and treatment efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the CD34+CD38- phenotype is used to identify LSCs, then LSC enrichment is achieved, but the population includes both normal and leukemic cells making identification unreliable
Solution Approach 1:
The patent segments the heterogeneous CD34+CD38- population by introducing functional assays (mouse engraftment, colony-forming unit assays) and molecular markers (cytogenetic abnormalities, gene expression profiles) to divide the population into distinct leukemic and normal subpopulations, thereby resolving the identification reliability issue
Solution Approach 2:
The patent changes the identification parameters from simple surface markers (CD34, CD38) to multiple parameters including functional capacity (engraftment efficiency, colony formation), molecular characteristics (cytogenetic abnormalities, gene expression), and phenotypic markers, enabling reliable distinction between leukemic and normal stem cells
2Reliability
If the mouse engraftment assay is used as the gold standard for LSC identification, then functional LSC definition is achieved, but the assay is cumbersome and often non-quantitative
Solution Approach 1:
The patent introduces intermediary markers and assays (molecular cytogenetic markers, gene expression profiles, alternative in vitro functional assays) that correlate with mouse engraftment capacity, serving as proxies that simplify the complex engraftment assay while maintaining reliability
Solution Approach 2:
The patent substitutes the complex in vivo mouse engraftment system with in vitro molecular and functional assays (qPCR for gene expression, FISH for cytogenetic abnormalities, colony-forming unit assays) that provide comparable reliability without the logistical complexity of animal work
3Productivity
If standard induction chemotherapy is used to treat AML, then complete remission is achieved in most patients, but LSCs are spared leading to relapse
Solution Approach 1:
The patent applies local quality by directing therapy specifically at the LSC compartment identified through molecular and functional markers, rather than uniform treatment of all leukemic cells, using approaches like targeted delivery to cells with specific gene expression profiles or cytogenetic abnormalities
Solution Approach 2:
The patent employs preliminary action by using molecular markers and functional assays to identify and characterize LSCs before treatment, enabling selection of therapies specifically tailored to target the identified LSC population and prevent relapse
Data Source
AI summary
Using the methods of the present invention, intermediate (int) levels of aldehyde dehydrogenase (ALDH) activity reliably distinguished leukemic CD34+CD38− cells capable of engrafting immunodeficient mice, from residual normal hematopoietic stem cells that exhibited relatively higher ALDH activity. Minimal residual disease (MRD) detected during complete remission was enriched for the CD34+CD38−ALDHint leukemic cells, and the presence of these cells after therapy highly correlated with subsequent clinical relapse. The methods of the present invention can distinguish normal from leukemic CD34+CD38− cells, and identifies those AML cells associated with relapse. Methods of prediction of relapse of AML patients and methods of treatment are also provided.