HCK is a survival determinant transactivated by mutated MYD88, and a direct target of ibrutinib

Blood. 2016 Jun 23;127(25):3237-52. doi: 10.1182/blood-2016-01-695098. Epub 2016 May 3.


Activating mutations in MYD88 are present in ∼95% of patients with Waldenström macroglobulinemia (WM), as well as other B-cell malignancies including activated B-cell (ABC) diffuse large B-cell lymphoma (DLBCL). In WM, mutated MYD88 triggers activation of Bruton tyrosine kinase (BTK). Ibrutinib, a pleiotropic kinase inhibitor that targets BTK, is highly active in patients with mutated MYD88. We observed that mutated MYD88 WM and ABC DLBCL cell lines, as well as primary WM cells show enhanced hematopoietic cell kinase (HCK) transcription and activation, and that HCK is activated by interleukin 6 (IL-6). Over-expression of mutated MYD88 triggers HCK and IL-6 transcription, whereas knockdown of HCK reduced survival and attenuated BTK, phosphoinositide 3-kinase/AKT, and mitogen-activated protein kinase/extracellular signal-regulated kinase signaling in mutated MYD88 WM and/or ABC DLBCL cells. Ibrutinib and the more potent HCK inhibitor A419259, blocked HCK activation and induced apoptosis in mutated MYD88 WM and ABC DLBCL cells. Docking and pull-down studies confirmed that HCK was a target of ibrutinib. Ibrutinib and A419259 also blocked adenosine triphosphate binding to HCK, whereas transduction of mutated MYD88 expressing WM cells with a mutated HCK gatekeeper greatly increased the half maximal effective concentration for ibrutinib and A419259. The findings support that HCK expression and activation is triggered by mutated MYD88, supports the growth and survival of mutated MYD88 WM and ABC DLBCL cells, and is a direct target of ibrutinib. HCK represents a novel target for therapeutic development in MYD88-mutated WM and ABC DLBCL, and possibly other diseases driven by mutated MYD88.

MeSH terms

  • Adenine / analogs & derivatives
  • Antineoplastic Agents / pharmacology*
  • Antineoplastic Agents / therapeutic use
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Cell Survival / genetics
  • Gene Expression Regulation, Leukemic / drug effects
  • Humans
  • Interleukin-6 / pharmacology
  • Lymphoma, Large B-Cell, Diffuse / drug therapy
  • Lymphoma, Large B-Cell, Diffuse / genetics
  • Lymphoma, Large B-Cell, Diffuse / pathology
  • Molecular Targeted Therapy
  • Mutant Proteins / physiology
  • Myeloid Differentiation Factor 88 / genetics
  • Myeloid Differentiation Factor 88 / physiology*
  • Piperidines
  • Proto-Oncogene Proteins c-hck / antagonists & inhibitors*
  • Proto-Oncogene Proteins c-hck / genetics*
  • Pyrazoles / pharmacology*
  • Pyrazoles / therapeutic use
  • Pyrimidines / pharmacology*
  • Pyrimidines / therapeutic use
  • Transcriptional Activation
  • Waldenstrom Macroglobulinemia / genetics
  • Waldenstrom Macroglobulinemia / pathology


  • Antineoplastic Agents
  • Interleukin-6
  • MYD88 protein, human
  • Mutant Proteins
  • Myeloid Differentiation Factor 88
  • Piperidines
  • Pyrazoles
  • Pyrimidines
  • ibrutinib
  • HCK protein, human
  • Proto-Oncogene Proteins c-hck
  • Adenine