IMR Press / FBL / Volume 10 / Issue 3 / DOI: 10.2741/1720

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.

Open Access Article
Docetaxel induces p53-dependent apoptosis and synergizes with farnesyl transferase inhibitor r115777 in human epithelial cancer cells
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1 Department of Experimental Oncology, National Institute of Tumours Fondazione G. Pascale, Naples, Italy
2 Department of Biochemistry and Biophysics, Second University of Naples, Via Costantinopoli, 16 80138, Naples, Italy
3 Division of Medical Oncology B, National Institute of Tumours Fondazione “G. Pascale” Naples, Italy

Academic Editor: Antonio Giordano

Front. Biosci. (Landmark Ed) 2005, 10(3), 2566–2575; https://doi.org/10.2741/1720
Published: 1 September 2005
(This article belongs to the Special Issue Gene targets for modulating cell growth)
Abstract

Docetaxel (Taxotere, DTX) is a promoter of apoptosis in cancer cells. Since cytotoxic mechanisms of DTX are not yet fully understood, we have investigated the effects of DTX on apoptosis and ras->Erk-mediated signal transduction in human epidermoid KB, colon HT-29 and breast HCC1937 cancer cells. We have found that the exposure to 0.78 or 1.56 or 2.5 ng/ml DTX for 48 h induced apoptosis and growth inhibition in about 50 % of KB, HCC1937 and HT-29 cell population, respectively. In these experimental conditions, PARP and caspase 3 cleavage was also showed in all cell lines. KB and HCC1937 cells express a wild type p53 while HT-29 display a mutated form. Interestingly, we have found that DTX reduces the expression of mutated p53 in HT-29 and increases the expression of wild type in KB and HCC1937 cells. Moreover, DTX reduces ubiquitination of the wild type p53 in KB and HCC1937 cells and increases the ubiquitin-conjugated form of mutated p53 in HT-29 cells. Furthermore, exposure of cancer cells to DTX for 48 h increases the expression and activity of Ras and up-regulates Raf-1 and the phosphorylated isoforms of Erk-1/2. On the bases of these data, we have hypothesized that the increased activity of the ras->erk-dependent pathway induced by DTX could be a protective signalling from the apoptosis caused by the drug. Therefore, we have used R115777, a farnesyl transferase inhibitor that inactivates ras, in combination with DTX. The combined treatment with DTX and R115777 resulted in a strong synergism in growth inhibition in the three cell lines. These data suggest the use of the combination in these therapeutic settings even if further experiments are required for the clinical translation.

Keywords
Docetaxel
p53
Apoptosis
R115777
Erk
ras
Epithelial Tumour Cells
Growth Inhibition
Synergism
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