title: AMP-activated protein kinase signaling is upregulated in papillary thyroid cancer.
abstract: AMP-activated protein kinase (AMPK) is activated by the depletion in cellular energy levels and allows adaptive changes in cell metabolism and cell survival. Recently, our group described that AMPK plays an important role in the regulation of iodide and glucose uptake in thyroid cells. However, AMPK signaling pathway in human thyroid carcinomas has not been investigated so far.
  
  
  OBJECTIVE
  To evaluate the expression and activity of AMPK in papillary thyroid carcinomas.
  
  
  METHODS
  We examined total and phosphorylated AMPK (tAMPK and pAMPK) and phosphorylated acetyl-CoA-carboxylase (pACC) expressions through imunohistochemistry, using a tissue microarray block composed of 73 papillary thyroid carcinomas (PAP CA) or microcarcinomas (PAP MCA) and six adenoma (AD) samples from patients followed at the Federal University Hospital. The expression levels were compared with the non-neoplastic tissues from the same patient. Two different pathologists analyzed the samples and attributed scores of staining intensity and the proportion of stained cells. A total index was obtained by multiplying the values of intensity and the proportion of stained cells (INTxPROP).
  
  
  RESULTS
  tAMPK, pAMPK, and pACC showed a predominant cytoplasmic staining in papillary carcinomas, adenomas, and non-neoplastic thyroid tissues. However, the intensity and the proportion of stained cells were higher in carcinomas, so that a significant increase was found in the INTxPROP score both in PAP CA and PAP MCA, when compared with their respective controls.
  
  
  CONCLUSIONS
  Our results show unequivocally that AMPK pathway is highly activated in papillary thyroid carcinomas; however, more studies are necessary to understand the pathophysiological significance of AMPK activation in thyroid carcinogenesis.
authors.affiliation: Serviço de Anatomia Patológica do Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Avenida Rodolpho Paulo Rocco 255, Ilha do Fundão, Rio de Janeiro, Brazil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Vidal
authors.forename: Bruno M
authors.initials: BM
authors.lastname: Andrade
authors.forename: Fernanda
authors.initials: F
authors.lastname: Vaisman
authors.forename: Juliana
authors.initials: J
authors.lastname: Cazarin
authors.forename: Luis Felipe Ribeiro
authors.initials: LF
authors.lastname: Pinto
authors.forename: Marisa Maria Dreyer
authors.initials: MM
authors.lastname: Breitenbach
authors.forename: Rossana
authors.initials: R
authors.lastname: Corbo
authors.forename: Adriana
authors.initials: A
authors.lastname: Caroli-Bottino
authors.forename: Fernando
authors.initials: F
authors.lastname: Soares
authors.forename: Mario
authors.initials: M
authors.lastname: Vaisman
authors.forename: Denise P
authors.initials: DP
authors.lastname: Carvalho
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000378:metabolism* / Q000473:pathology; D002291:Carcinoma, Papillary; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D008875:Middle Aged; D010766:Phosphorylation / Q000502:physiology; D012189:Retrospective Studies; D015398:Signal Transduction / Q000502:physiology*; D000077273:Thyroid Cancer, Papillary; D013961:Thyroid Gland / Q000378:metabolism* / Q000473:pathology; D013964:Thyroid Neoplasms / Q000378:metabolism* / Q000473:pathology; D015854:Up-Regulation / Q000502:physiology; D055815:Young Adult
chemical_list: D055372:AMP-Activated Protein Kinases; C526180:PRKAA1 protein, human