title: Higher expression of the heterogeneous nuclear ribonucleoprotein k in melanoma.
abstract: BACKGROUND
  The heterogeneous nuclear ribonucleoprotein (hnRNP) K is an essential RNA and DNA binding protein involved in gene expression and signal transduction. The role of hnRNP K in cancer is relatively understudied. However, several cellular functions strongly indicate that hnRNP K is involved in tumorigenesis. Oncogenes c-Src, c-myc, and eIF4E are regulated by hnRNP K. We have shown an increased cytoplasmic hnRNP K in pancreatic cancer. In the present study, we investigated the altered expression of hnRNP K protein and its correlation with p-ERK in melanoma using human melanoma cell lines and tissue microarray.
  
  
  METHODS
  The protein levels of hnRNP K and p-ERK in 8 human melanoma cell lines and a melanoma progression tissue microarray containing 80 melanoma, 23 dysplastic nevi, and 14 benign nevi specimens were analyzed using Western blot and immunohistochemistry analysis. hnRNP K was knocked down by siRNA, and its effect on melanoma cells was assessed.
  
  
  RESULTS
  We showed a higher hnRNP K protein level in both melanoma cell lines and melanoma tissue specimens, which correlated with a higher c-myc expression. An increase in the cytoplasmic hnRNP K and eIF4E protein levels in melanoma cells is also seen. p-ERK level was also higher in dysplastic nevi and melanoma tissues, but did not correlate with hnRNP K protein level. We then demonstrated that knocking down of hnRNP K by siRNA inhibited melanoma cell growth and colony formation, as well as c-myc expression.
  
  
  CONCLUSIONS
  hnRNP K expression correlated with melanoma and may play a role in melanoma tumorigenesis.
authors.affiliation: Department of Surgery, Arizona Cancer Center, University of Arizona, Tucson, AZ, USA.
authors.forename: Fushi
authors.initials: F
authors.lastname: Wen
authors.forename: Alex
authors.initials: A
authors.lastname: Shen
authors.forename: Reneé
authors.initials: R
authors.lastname: Shanas
authors.forename: Achyut
authors.initials: A
authors.lastname: Bhattacharyya
authors.forename: Fangru
authors.initials: F
authors.lastname: Lian
authors.forename: Galen
authors.initials: G
authors.lastname: Hostetter
authors.forename: Jiaqi
authors.initials: J
authors.lastname: Shi
mesh_terms: D015153:Blotting, Western; D003593:Cytoplasm / Q000378:metabolism; D004416:Dysplastic Nevus Syndrome / Q000378:metabolism / Q000473:pathology; D039561:Eukaryotic Initiation Factor-4E / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D034641:Heterogeneous-Nuclear Ribonucleoprotein K / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D008544:Melanocytes / Q000378:metabolism / Q000473:pathology; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation; D011379:Prognosis; D034741:RNA, Small Interfering / Q000494:pharmacology; D046888:Tissue Array Analysis; D014407:Tumor Cells, Cultured
chemical_list: D039561:Eukaryotic Initiation Factor-4E; D034641:Heterogeneous-Nuclear Ribonucleoprotein K; D034741:RNA, Small Interfering; D048049:Extracellular Signal-Regulated MAP Kinases