Acute Leukemia Cells Resistant to PI3K/mTOR Inhibition Display Upregulation of P2RY14 Expression

Clin Epigenetics. 2018 Jun 19;10:83. doi: 10.1186/s13148-018-0516-x. eCollection 2018.

Abstract

The PI3K/mTOR pathway is the second most frequently deregulated pathway in a majority of cancers such as breast cancer, lung cancer, and melanomas as well as leukemia. Mutations in the genes coding for receptor tyrosine kinases (RTKs) and G-protein-coupled receptors (GPCRs) are quite common in all forms of acute leukemia. This can be a major cause of deregulation of the PI3K-mTOR pathway. To understand how cells display resistance to the dual PI3K/mTOR inhibitor, we used a panel of 25 acute leukemia cell lines. We observed that while a number of cell lines displayed sensitivity to the dual PI3K/mTOR pathway inhibitor PKI-587, many cells displayed substantial resistance. Cells sensitive to PKI-587 also showed aberrant activation of PI3K/mTOR pathway components such as AKT and S6K and also displayed sensitivity to a panel of various other PI3K/mTOR inhibitors. Using RNA sequencing data, we observed that expression of a G protein-coupled receptor, P2RY14, was upregulated nine-fold in cells showing resistance to the PI3K/mTOR inhibitor. P2RY14 has not been much studied in hematologic malignancies. However, this receptor seems to have a role in the localization of hematopoietic stem cells (HSCs) and in promoting regenerative capabilities following injury. We observed that acute lymphoblastic leukemia (ALL) and FLT3-ITD-positive acute myeloid leukemia (AML) patients with higher expression of P2RY14 mRNA displayed relatively poor survival compared to patients carrying lower expression of P2RY14 suggesting a role of P2RY14 in patient survival. To understand the role of this receptor in cell signaling, we used phospho-protein arrays and observed activation of distinct signaling cascades. Furthermore, array data were verified using murine pro-B cell line Ba/F3 stably transfected with P2RY14. We observed that activation of P2RY14 by its ligand, UDP-glucose, resulted in selective induction of ERK1/2 phosphorylation. Taken together, our data suggest that acute leukemia cells resistant to PI3K/mTOR inhibition display upregulation of a GPCR, P2RY14, which has a role in patient survival and also couples to the activation of ERK signaling.

Keywords: ALL; AML; B-ALL; P2RY14.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Humans
  • MAP Kinase Signaling System / genetics
  • Mitogen-Activated Protein Kinase 1 / metabolism*
  • Mitogen-Activated Protein Kinase 3 / metabolism*
  • Morpholines / pharmacology
  • Phosphoinositide-3 Kinase Inhibitors
  • Phosphorylation
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / metabolism*
  • Receptors, Purinergic P2Y / genetics
  • Receptors, Purinergic P2Y / metabolism*
  • TOR Serine-Threonine Kinases / antagonists & inhibitors
  • Triazines / pharmacology
  • Up-Regulation

Substances

  • Morpholines
  • P2RY14 protein, human
  • Phosphoinositide-3 Kinase Inhibitors
  • Receptors, Purinergic P2Y
  • Triazines
  • gedatolisib
  • MTOR protein, human
  • TOR Serine-Threonine Kinases
  • MAPK1 protein, human
  • MAPK3 protein, human
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3