# SPINK2 silencing suppresses leukemic proliferation and restores myeloid commitment via MECOM downregulation in acute myeloid leukaemia

## TL;DR

Silencing SPINK2 in acute myeloid leukemia reduces cancer cell growth and promotes normal cell development, especially in patients with complex karyotypes.

## Contribution

SPINK2 is identified as a novel therapeutic target in complex karyotype AML through its link to MECOM and cell cycle regulation.

## Key findings

- SPINK2 silencing impairs proliferation and induces myeloid commitment in complex karyotype AML cells.
- SPINK2 is strongly associated with S-phase cell cycle genes in AML.
- SPINK2 and MECOM expression are significantly linked in complex karyotype leukemias but not in other AML subsets.

## Abstract

Myeloid leukaemias harboring complex karyotypes present several unrelated cytogenetic abnormalities and form a distinct subset of AML linked to a dismal prognosis. Currently, no effective options are available for the treatment of those patients, and the discovery of novel therapeutic strategies represent an urgent clinical priority. We previously developed a bioinformatic framework for the identification of novel molecular vulnerabilities for disease stratification and treatment and observed SPINK2, a serine protease inhibitor Kazal-type 2, as a novel and promising candidate target in AML, with particularly pronounced effects in complex karyotype patients. Using publicly available bulk and single cell RNA-seq datasets, we discovered a robust association between SPINK2 and cell cycle regulators, most notably S-phase genes. By performing shRNA-mediated genetic manipulation of SPINK2 expression in a complex karyotype AML cell lines, we observed a profound impairment of proliferation coupled with an induction of terminal myeloid commitment. Moreover, SPINK2-deficient FUJIOKA cells revealed a significant association between SPINK2 and MECOM expression, consistent with findings in patients harbouring complex karyotypes, yet absent in other AML subsets from the TARGET-AML cohort. Our findings suggest a novel potential correlation between SPINK2 and MECOM expression in complex karyotype leukemias and warrant further investigation into the underlying molecular mechanisms through which the SPINK2-MECOM axis enforces aberrant self-renewal and the development of novel targeted approaches aimed at modulating its expression in complex karyotypic AML.