FTY720 PP2A Activation for TKI-Resistant Leukemic Stem Cells

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Solution Overview

Problem

Chronic myeloid leukemia (CML) quiescent hematopoietic stem cells are resistant to tyrosine kinase inhibitors (TKIs) due to their reliance on BCR-ABL1 expression for survival and self-renewal, making it challenging to achieve long-term remission or cure with current therapies.

Innovation Solution

The use of FTY720 and its derivatives, which selectively activate protein phosphatase 2A (PP2A) by disrupting the SET-PP2A interaction, thereby inhibiting JAK2 and β-catenin-dependent survival pathways in leukemic stem cells without affecting normal cells, leading to apoptosis of TKI-resistant CML cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If tyrosine kinase inhibitors (TKIs) are used to treat CML, then TKI-sensitive proliferating leukemic cells are suppressed, but quiescent leukemic stem cells persist and cause relapse

Engineering Contradiction:

Improvelong-term remissionVSAvoidTKI resistance of quiescent cells

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent uses FTY720 as an intermediary compound that activates PP2A phosphatase activity. This intermediary mechanism allows selective targeting of quiescent leukemic stem cells through a different pathway (PP2A activation) rather than direct BCR-ABL1 kinase inhibition, thereby overcoming TKI resistance while preserving the benefits of TKI therapy

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the therapeutic parameter from BCR-ABL1 kinase inhibition (TKIs) to PP2A phosphatase activation (FTY720). This parameter change enables the treatment to affect quiescent stem cells that are insensitive to kinase inhibition, as PP2A activation targets different survival pathways including JAK2 and STAT3 that are active in quiescent cells

Inventive Principle:

Principle #35Parameter changes

2Productivity

If FTY720 is used to activate PP2A in leukemic stem cells, then selective apoptosis of leukemic cells is induced, but normal hematopoietic stem cells are spared due to their high baseline PP2A activity

Engineering Contradiction:

Improveselective killing of leukemic cellsVSAvoidtoxicity to normal cells

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent exploits the local quality difference in PP2A activity between leukemic and normal cells. Leukemic stem cells have suppressed PP2A activity due to SET inhibition, while normal cells maintain high baseline PP2A activity. FTY720 selectively activates PP2A in leukemic cells where it is suppressed, creating a localized therapeutic effect without affecting normal cells that already have sufficient PP2A activity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent converts the harmful suppression of PP2A activity in leukemic cells (caused by SET overexpression) into a therapeutic opportunity. By using FTY720 to reactivate PP2A specifically in these cells, the previously harmful molecular alteration becomes the target for selective elimination of leukemic stem cells

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

FTY720 and its derivatives effectively suppress the survival and self-renewal of leukemic stem cells by restoring PP2A activity, potentially leading to long-term remission or cure of CML by selectively targeting and eliminating quiescent CML stem cells while sparing normal hematopoietic stem cells.

Implementation Method 1

FTY720 and its derivatives, which selectively activate protein phosphatase 2A (PP2A) by disrupting the SET-PP2A interaction

Methodology Applied

Scientific EffectProtein phosphatase 2A (PP2A) activation: Enzyme

Implementation Method 2

FTY720-induced PP2A activity promotes BCR-ABL1 inactivation/degradation and inhibition of survival factors (e.g. JAK2, Akt and ERK1/2)

Methodology Applied

Scientific EffectProtein dephosphorylation: Enzyme

Implementation Method 3

This results in apoptosis of CD34+ progenitors from TKI-sensitive and -resistant Ph+ patients but not from healthy individuals

Methodology Applied

Scientific EffectApoptosis:

Implementation Method 4

inhibition of survival factors (e.g. JAK2, Akt and ERK1/2)

Methodology Applied

Scientific EffectSignal transduction inhibition: Enzyme

Implementation Method 5

BCR-ABL1 is a tyrosine kinase whose constitutive activity in hematopoietic progenitors is essential for CML emergence, maintenance and progression

Methodology Applied

Scientific EffectTyrosine kinase activity: Enzyme

Data Source

PatentUS9220706B2Inhibition of leukemic stem cells by PP2A activating agents

Publication Date: 2015.12.29 OHIO STATE INNOVATION FOUND

AI summary

A method of inhibiting the growth of leukemic hematopoietic stem cells in a subject with leukemia is described. The method includes administering a therapeutically effective amount of a composition including a compound of formula I: I wherein R1 is independently selected from hydrogen and methyl; R2 is selected from the group consisting of 4,8-dimethyl-non-1-enyl, 4,8-dimethyl-nonyl, non-1-enyl, and nonanyl groups; X is a carboxyl, phosphonic, or sulfonic moiety, and n is an integer from 1 to 6, or a compound of Formula II: II wherein R1 is a C6-C12 alkyl or C6-C12 alkoxy group; R2 is independently selected from the group consisting of hydrogen, methoxy, and hydroxyl; and R3 is an alkyl or cycloalkyl group; or a pharmaceutically acceptable salt thereof.