Novel actions of next-generation taxanes benefit advanced stages of prostate cancer.

Abstract

PURPOSE:

To improve the outcomes of patients with castration-resistant prostate cancer (CRPC), there is an urgent need for more effective therapies and approaches that individualize specific treatments for patients with CRPC. These studies compared the novel taxane cabazitaxel with the previous generation docetaxel, and aimed to determine which tumors are most likely to respond.

EXPERIMENTAL DESIGN:

Cabazitaxel and docetaxel were compared via in vitro modeling to determine the molecular mechanism, biochemical and cell biologic impact, and cell proliferation, which was further assessed ex vivo in human tumor explants. Isogenic pairs of RB knockdown and control cells were interrogated in vitro and in xenograft tumors for cabazitaxel response.

RESULTS:

The data herein show that (i) cabazitaxel exerts stronger cytostatic and cytotoxic response compared with docetaxel, especially in CRPC; (ii) cabazitaxel induces aberrant mitosis, leading to pyknotic and multinucleated cells; (iii) taxanes do not act through the androgen receptor (AR); (iv) gene-expression profiling reveals distinct molecular actions for cabazitaxel; and (v) tumors that have progressed to castration resistance via loss of RB show enhanced sensitivity to cabazitaxel.

CONCLUSIONS:

Cabazitaxel not only induces improved cytostatic and cytotoxic effects, but also affects distinct molecular pathways, compared with docetaxel, which could underlie its efficacy after docetaxel treatment has failed in patients with CRPC. Finally, RB is identified as the first potential biomarker that could define the therapeutic response to taxanes in metastatic CRPC. This would suggest that loss of RB function induces sensitization to taxanes, which could benefit up to 50% of CRPC cases.

• Authors: Renée de Leeuw, Lisa D Berman-Booty, Matthew J Schiewer, Stephen J Ciment, Robert B Den, Adam P Dicker, William K Kelly, Edouard J Trabulsi, Costas D Lallas, Leonard G Gomella, Karen E Knudsen
• Journal: Clinical cancer research : an official journal of the American Association for Cancer Research (Clin Cancer Res) Vol. 21 Issue 4 Pg. 795-807 (Feb 15 2015) ISSN: 1557-3265 [Electronic] United States
• PMID: 25691773 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)
• Copyright: ©2015 American Association for Cancer Research.

Chemical References

• Antineoplastic Agents
• Taxoids
• Docetaxel
• cabazitaxel

Topics

• Adenocarcinoma (drug therapy)
• Animals
• Antineoplastic Agents (pharmacology)
• Cell Line, Tumor
• Docetaxel
• Flow Cytometry
• Humans
• Immunoblotting
• Male
• Mice
• Microscopy, Fluorescence
• Models, Molecular
• Oligonucleotide Array Sequence Analysis
• Prostatic Neoplasms, Castration-Resistant (drug therapy)
• Taxoids (pharmacology)
• Transcriptome
• Xenograft Model Antitumor Assays