title: PP6C hotspot mutations in melanoma display sensitivity to Aurora kinase inhibition.
abstract: Recent whole genome melanoma sequencing studies have identified recurrent mutations in the gene encoding the catalytic subunit of serine/threonine phosphatase 6 (PPP6C/PP6C). However, the biochemical, functional, and clinical ramifications of these mutations are unknown. Sequencing PP6C from patients with melanoma (233 primary and 77 metastatic specimens) with extended prospective clinical outcome revealed a large number of hotspot mutations in patients with both primary and metastatic melanoma. Despite minimal association between stage and presence of PP6C mutations in patients with primary melanoma, a subpopulation of cells within each tumor did contain PP6C mutations, suggesting PP6C mutation is an early, but non-tumor-initiating event in melanoma. Among patients with primary melanoma with PP6C mutations, patients with stop mutations had significantly shorter recurrence-free survival compared with patients without stop mutations. In addition, PP6C mutations were independent of commonly observed BRAF and NRAS mutations. Biochemically, PP6C mutations could be classified as those that interact with PP6C regulatory subunits and those that do not. Mutations that did not bind to PP6C regulatory subunits were associated with increased phosphorylation of Aurora kinase, a PP6C substrate, and mitotic defects. However, both classes of PP6C mutations led to increased sensitivity to Aurora kinase inhibition. Together, these data support for the first time that PP6C mutations are molecularly, biochemically, and clinically heterogeneous.
  
  
  CONCLUSIONS
  PP6C mutations have distinct functional and clinical consequences in melanoma, and confer sensitivity to Aurora A kinase inhibitors.
authors: New York University School of Medicine, 550 1st Avenue, New York, NY 10016. lawrence.gardner@nyumc.org.
authors: Heidi L
authors: HL
authors: Gold
authors: Jordan
authors: J
authors: Wengrod
authors: Eleazar Vega-Saenz
authors: EV
authors: de Miera
authors: Ding
authors: D
authors: Wang
authors: Nathaniel
authors: N
authors: Fleming
authors: Lisa
authors: L
authors: Sikkema
authors: Tomas
authors: T
authors: Kirchhoff
authors: Tsivia
authors: T
authors: Hochman
authors: Judith D
authors: JD
authors: Goldberg
authors: Iman
authors: I
authors: Osman
authors: Lawrence B
authors: LB
authors: Gardner
mesh_terms: D064127:Aurora Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D008297:Male; D008545:Melanoma / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D009154:Mutation; D009367:Neoplasm Staging; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D011379:Prognosis; D047428:Protein Kinase Inhibitors; D021122:Protein Subunits; D012878:Skin Neoplasms / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology
chemical_list: D004791:Enzyme Inhibitors; D047428:Protein Kinase Inhibitors; D021122:Protein Subunits; D064127:Aurora Kinases; D010749:Phosphoprotein Phosphatases; C106079:protein phosphatase 6