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Rapamycin effects on mTOR signaling in benign, premalignant and malignant human breast epithelial cells

So Hee Kim1, Kim Zukowski, Raymond F Novak

  • 1Wayne State University, Detroit, MI 48201, USA.

Anticancer Research
|May 6, 2009
PubMed

Insights

Rapamycin effectively inhibits cancer cell growth in early stages but shows resistance in tumor cells. Targeting mTOR and STAT3 signaling may prevent breast cancer progression and recurrence.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cell Biology

Background:

  • Rapamycin, an mTOR inhibitor, is under investigation for cancer treatment.
  • Rapamycin resistance is a known issue in human breast epithelial tumor cells.

Purpose of the Study:

  • To investigate the effects of rapamycin on mTOR signaling and resistance in benign, premalignant, and tumor human breast epithelial cells.
  • To evaluate rapamycin's efficacy in inhibiting cell proliferation, cell cycle, and specific signaling pathways.

Main Methods:

  • Utilized a lineage of human breast epithelial cells ranging from benign (MCF10A) to premalignant (MCF10AT; MCF10ATG3B) and tumor (MCF10CA1a) types.
  • Assessed rapamycin's impact on mTOR signaling, including p70S6K and S6RP phosphorylation, and STAT3 phosphorylation.

Main Results:

  • Rapamycin demonstrated significant inhibition of cell proliferation, cell cycle, and mTOR signaling in benign and premalignant cells.
  • Rapamycin resistance was observed in tumor cells, evidenced by reduced inhibition of p70S6K and S6RP phosphorylation, with RS6P showing minimal response.
  • Differential inhibition of STAT3 phosphorylation by rapamycin was noted across the cell lineage.

Conclusions:

  • mTOR signaling and STAT3 phosphorylation inhibition by rapamycin is most effective in benign and premalignant breast cells.
  • These findings suggest potential therapeutic applications for rapamycin in treating proliferative breast disease and preventing cancer development or recurrence.

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