Experimental studies with liarozole (R 75,251): an antitumoral agent which inhibits retinoic acid breakdown
R De Coster1, W Wouters, R Van Ginckel
1Janssen Research Foundation, Beerse, Belgium.
Abstract:
Liarozole reduced tumor growth in the androgen-dependent Dunning-G and the androgen-independent Dunning MatLu rat prostate carcinoma models as well as in patients with metastatic prostate cancer who had relapsed after orchiectomy. In vitro, liarozole did not have cytostatic properties, as measured by cell proliferation in breast MCF-7 and prostate DU145 and LNCaP carcinoma cell lines. It did not alter the metabolism of labeled testosterone i.e. the 5 alpha-reductase in cultured rat prostatic cells. In mouse F9 teratocarcinoma cells liarozole did not show any retinoid-like properties but enhanced the plasminogen activator production induced by retinoic acid. Furthermore, liarozole and retinoic acid similarly reduced the growth of the androgen-dependent Dunning-G tumor in nude mice and inhibited tumor promotion elicited by phorbol ester in mouse skin. These data have raised the hypothesis that the antitumoral properties of liarozole may be related to inhibition of retinoic acid degradation, catalyzed by a P-450-dependent enzyme that is blocked by the drug.
Insights
Liarozole effectively reduced tumor growth in prostate cancer models and patients. Its anti-tumor effects may stem from inhibiting retinoic acid degradation by a P-450 enzyme.
Area of Science:
- Oncology
- Pharmacology
Background:
- Prostate cancer remains a significant health concern, with limited treatment options for advanced stages.
- Androgen-dependent and independent prostate cancer models are crucial for evaluating therapeutic strategies.
Purpose of the Study:
- To investigate the anti-tumor efficacy of liarozole in various prostate cancer models.
- To explore the in vitro mechanisms underlying liarozole's anti-cancer properties.
Main Methods:
- Tumor growth assessment in androgen-dependent (Dunning-G) and androgen-independent (Dunning MatLu) rat prostate carcinoma models.
- In vitro cell proliferation assays using breast (MCF-7) and prostate (DU145, LNCaP) carcinoma cell lines.
- Evaluation of testosterone metabolism (5 alpha-reductase activity) and retinoid-like properties in F9 teratocarcinoma cells.
Main Results:
- Liarozole significantly reduced tumor growth in both Dunning-G and Dunning MatLu rat models.
- No cytostatic effects were observed in vitro for liarozole across tested human cancer cell lines.
- Liarozole enhanced retinoic acid-induced plasminogen activator production in F9 teratocarcinoma cells and reduced tumor growth in vivo.
Conclusions:
- Liarozole demonstrates potent anti-tumor activity against prostate cancer in preclinical models and in patients with metastatic disease.
- The anti-cancer mechanism of liarozole is hypothesized to involve the inhibition of retinoic acid degradation by a P-450-dependent enzyme.
