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Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death
09:18

Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death

Published on: December 27, 2016

pp32/PHAPI determines the apoptosis response of non-small-cell lung cancer

S Hoffarth1, A Zitzer, R Wiewrodt

  • 1Department of Medicine (Cancer Research), West German Cancer Center, University Hospital Essen, Essen, Germany.

Cell Death and Differentiation
|October 27, 2007
PubMed

Insights

Cancer cells resist apoptosis, hindering therapy. The protein pp32/putative human HLA class II-associated protein (pp32/PHAPI) restores apoptosis in non-small cell lung cancer (NSCLC) and predicts better chemotherapy outcomes.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cancer Research

Background:

  • Malignant transformation involves evading apoptosis, leading to drug resistance in cancer cells.
  • Understanding apoptosis defects is crucial for identifying prognostic markers and developing new therapies.

Purpose of the Study:

  • To investigate drug-induced apoptosis in non-small cell lung cancer (NSCLC) cells.
  • To identify molecular mechanisms underlying primary drug resistance in NSCLC.
  • To evaluate the role of pp32/putative human HLA class II-associated protein (pp32/PHAPI) in apoptosis and its therapeutic potential.

Main Methods:

  • Functional analysis of drug-induced apoptosis in human NSCLC cells.
  • Assessing cytochrome c-induced apoptosome formation and caspase activation (caspase-9 and -3).
  • In vitro and in vivo studies using recombinant pp32/PHAPI and conditional expression systems.
  • Immunohistochemical analysis of pp32/PHAPI expression in NSCLC patient tumor samples.

Main Results:

  • Primary drug resistance in NSCLC correlated with defects in apoptosome-dependent caspase activation.
  • Cytochrome c-induced apoptosome formation was intact, but caspase-9 and -3 activation was abolished in resistant cells.
  • Recombinant pp32/PHAPI restored defective caspase activation in vitro.
  • Conditional pp32/PHAPI expression sensitized NSCLC cells to apoptosis in vitro and in vivo.
  • Higher pp32/PHAPI expression in NSCLC tumors correlated with improved patient outcomes after chemotherapy.

Conclusions:

  • pp32/PHAPI acts as a regulator of apoptosis in cancer cells, both in vitro and in vivo.
  • pp32/PHAPI is a potential predictor of survival in patients with advanced NSCLC undergoing chemotherapy.
  • Targeting pp32/PHAPI may offer a novel therapeutic strategy for overcoming drug resistance in NSCLC.

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