# Monoallelic KRAS (G13C) mutation triggers dysregulated expansion in induced pluripotent stem cell-derived hematopoietic progenitor cells

## TL;DR

A single KRAS mutation causes abnormal expansion in blood cell precursors, suggesting a role in a rare blood disorder and offering new treatment approaches.

## Contribution

Demonstrates that monoallelic KRAS (G13C) mutation leads to dysregulated expansion in non-transformed hematopoietic progenitor cells using iPSC models.

## Key findings

- KRAS (G13C)-HPCs show dysregulated expansion with altered cell-cycle and apoptosis responses after cytokine stimulation.
- BCL-xL expression is increased in mutant HPCs, indicating a potential therapeutic target.
- MEK and BCL-2/BCL-xL inhibitors selectively inhibit KRAS (G13C)-HPC expansion in patient-derived samples.

## Abstract

Although oncogenic RAS mutants are thought to exert mutagenic effects upon blood cells, it remains uncertain how a single oncogenic RAS impacts non-transformed multipotent hematopoietic stem or progenitor cells (HPCs). Such potential pre-malignant status may characterize HPCs in patients with RAS-associated autoimmune lymphoproliferative syndrome-like disease (RALD). This study sought to elucidate the biological and molecular alterations in human HPCs carrying monoallelic mutant KRAS (G13C) with no other oncogene mutations.

We utilized induced pluripotent stem cells (iPSCs) derived from two unrelated RALD patients. Isogenic HPC pairs harboring either wild-type KRAS or monoallelic KRAS (G13C) alone obtained following differentiation enabled reliable comparative analyses. The compound screening was conducted with an established platform using KRAS (G13C) iPSCs and differentiated HPCs.

Cell culture assays revealed that monoallelic KRAS (G13C) impacted both myeloid differentiation and expansion characteristics of iPSC-derived HPCs. Comprehensive RNA-sequencing analysis depicted close clustering of HPC samples within the isogenic group, warranting that comparative studies should be performed within the same genetic background. When compared with no stimulation, iPSC-derived KRAS (G13C)-HPCs showed marked similarity with the wild-type isogenic control in transcriptomic profiles. After stimulation with cytokines, however, KRAS (G13C)-HPCs exhibited obvious aberrant cell-cycle and apoptosis responses, compatible with "dysregulated expansion," demonstrated by molecular and biological assessment. Increased BCL-xL expression was identified amongst other molecular changes unique to mutant HPCs. With screening platforms established for therapeutic intervention, we observed selective activity against KRAS (G13C)-HPC expansion in several candidate compounds, most notably in a MEK- and a BCL-2/BCL-xL-inhibitor. These two compounds demonstrated selective inhibitory effects on KRAS (G13C)-HPCs even with primary patient samples when combined.

Our findings indicate that a monoallelic oncogenic KRAS can confer dysregulated expansion characteristics to non-transformed HPCs, which may constitute a pathological condition in RALD hematopoiesis. The use of iPSC-based screening platforms will lead to discovering treatments that enable selective inhibition of RAS-mutated HPC clones.

The online version contains supplementary material available at 10.1186/s13287-024-03723-2.