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Immunohistochemistry of apoptosis-related proteins in retinoblastoma

Renato José Mendonça Natalino1, Célia Beatriz Gianotti Antoneli2, Karina de Cássia Braga Ribeiro3

  • 1Department of Pathology, A.C. Camargo Cancer Center, Sao Paulo, Brazil.

Pathology, Research and Practice
|October 5, 2016
PubMed

Insights

Retinoblastoma, a childhood eye cancer, involves inactive retinoblastoma protein (pRb). This study reveals pro-apoptotic proteins are more common than anti-apoptotic ones, with Bcl-xL potentially blocking cell death.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cellular Biology

Background:

  • Retinoblastoma is the most frequent childhood intraocular malignancy.
  • It arises from the inactivation of the retinoblastoma protein (pRb).
  • pRb inactivation leads to increased cell cycle and apoptotic protein activity.

Purpose of the Study:

  • To investigate the immunohistochemistry profile of apoptotic-related proteins in retinoblastoma.
  • To assess the correlation between apoptotic protein expression and tumor stage or patient survival.

Main Methods:

  • Immunohistochemistry was performed on tissue microarrays from 93 retinoblastoma patients.
  • Evaluated proteins included Apaf-1, Bak, Bax, Bcl-2, Bcl-xL, Bim-long, MDM2, p53, pro-caspase-3, PUMA, Smac/DIABLO, and cleaved caspase-3.
  • Reactions were analyzed via optical microscopy and the ACIS III® platform.

Main Results:

  • Pro-apoptotic proteins (Apaf-1, Bax, p53, PUMA, Smac/DIABLO) were more frequently expressed than anti-apoptotic proteins (Bcl-2, Bcl-xL, MDM2).
  • The anti-apoptotic protein Bcl-xL showed a negative correlation with cleaved caspase-3, a marker of apoptosis.
  • Elevated Bcl-xL expression may be associated with a block in apoptosis.

Conclusions:

  • The expression patterns of apoptotic proteins differ in retinoblastoma.
  • Bcl-xL's negative correlation with cleaved caspase-3 suggests its role in inhibiting apoptosis in retinoblastoma.
  • Further research into Bcl-xL's function could offer therapeutic targets for retinoblastoma.
Keywords:
ApoptosisRetinoblastomabcl-X protein

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