title: A targeted knockdown screen of genes coding for phosphoinositide modulators identifies PIP4K2A as required for acute myeloid leukemia cell proliferation and survival.
abstract: Given the importance of deregulated phosphoinositide (PI) signaling in leukemic hematopoiesis, genes coding for proteins that regulate PI metabolism may have significant and as yet unappreciated roles in leukemia. We performed a targeted knockdown (KD) screen of PI modulator genes in human acute myeloid leukemia (AML) cells and identified candidates required to sustain proliferation or prevent apoptosis. One of these, the lipid kinase phosphatidylinositol-5-phosphate 4-kinase, type II, alpha (PIP4K2A) regulates cellular levels of phosphatidylinositol-5-phosphate (PtsIns5P) and phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P₂). We found PIP4K2A to be essential for the clonogenic and leukemia-initiating potential of human AML cells, and for the clonogenic potential of murine MLL-AF9 AML cells. Importantly, PIP4K2A is also required for the clonogenic potential of primary human AML cells. Its KD results in accumulation of the cyclin-dependent kinase inhibitors CDKN1A and CDKN1B, G₁ cell cycle arrest and apoptosis. Both CDKN1A accumulation and apoptosis were partially dependent on activation of the mTOR pathway. Critically, however, PIP4K2A KD in normal hematopoietic stem and progenitor cells, both murine and human, did not adversely impact either clonogenic or multilineage differentiation potential, indicating a selective dependency that we suggest may be the consequence of the regulation of different transcriptional programs in normal versus malignant cells. Thus, PIP4K2A is a novel candidate therapeutic target in myeloid malignancy.
authors.affiliation: Inositide Laboratory, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, M20 4BX, United Kingdom.|Leukaemia Biology Laboratory, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, M20 4BX, United Kingdom.
authors.forename: Julian G
authors.initials: JG
authors.lastname: Jude
authors.affiliation: Leukaemia Biology Laboratory, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, M20 4BX, United Kingdom.
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Spencer
authors.affiliation: Leukaemia Biology Laboratory, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, M20 4BX, United Kingdom.
authors.forename: Xu
authors.initials: X
authors.lastname: Huang
authors.affiliation: Leukaemia Biology Laboratory, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, M20 4BX, United Kingdom.
authors.forename: Tim D D
authors.initials: TDD
authors.lastname: Somerville
authors.affiliation: Inositide Laboratory, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, M20 4BX, United Kingdom.
authors.forename: David R
authors.initials: DR
authors.lastname: Jones
authors.affiliation: Inositide Laboratory, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, M20 4BX, United Kingdom.
authors.forename: Nullin
authors.initials: N
authors.lastname: Divecha
authors.affiliation: Leukaemia Biology Laboratory, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, M20 4BX, United Kingdom.
authors.forename: Tim C P
authors.initials: TCP
authors.lastname: Somervaille
mesh_terms: D000818:Animals; D017209:Apoptosis; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival / Q000235:genetics; D016000:Cluster Analysis; D004789:Enzyme Activation; D020869:Gene Expression Profiling; D055785:Gene Knockdown Techniques; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D015470:Leukemia, Myeloid, Acute / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008822:Mice, Transgenic; D014411:Neoplastic Stem Cells / Q000378:metabolism; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics* / Q000378:metabolism; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D014410:Tumor Stem Cell Assay
chemical_list: D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; C113567:phosphatidylinositol 5-phosphate; C514871:PIP4K2A protein, human; D017853:Phosphotransferases (Alcohol Group Acceptor); D058570:TOR Serine-Threonine Kinases