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Hyperactive androgen receptor in prostate cancer: what does it mean for new therapy concepts?
Z Culig1, A Hobisch, A Hittmair
1Department of Urology, University of Innsbruck, Austria.
Abstract:
Investigations on androgen signaling alterations in the late stages of prostate cancer revealed new molecular mechanisms that may be in part responsible for failure of endocrine therapy. Both primary and metastatic lesions from prostate cancer express androgen receptor protein. Amplification of androgen receptor gene occurs in a subset of prostate cancer patients. Several point mutations of androgen receptor gene have been described; they generate receptors which are functionally activated by androgens, other steroids, and even by antihormones. The frequency of androgen receptor mutations may be high in tumor metastases. Functional activity of androgen receptor is influenced by nonsteroidal factors, such as peptide growth factors and second messengers. Thus, prostate cancer cells adapt to low androgen environment by various mechanisms utilizing androgen receptor. Therefore, new strategies for switching off the androgen receptor are needed.
Insights
Prostate cancer cells adapt to low androgen conditions by altering androgen receptor (AR) signaling through mutations and gene amplification. New strategies are needed to inhibit AR activity, overcoming endocrine therapy resistance.
Area of Science:
- Oncology
- Molecular Biology
- Endocrinology
Background:
- Prostate cancer progression involves alterations in androgen signaling.
- Androgen receptor (AR) protein is expressed in primary and metastatic prostate cancer lesions.
- Endocrine therapy for prostate cancer can fail due to molecular adaptations.
Purpose of the Study:
- To investigate molecular mechanisms of androgen signaling alterations in late-stage prostate cancer.
- To understand how prostate cancer cells adapt to low androgen environments.
- To identify the need for novel therapeutic strategies targeting AR.
Main Methods:
- Analysis of androgen receptor protein expression in primary and metastatic lesions.
- Detection of androgen receptor gene amplification in patient subsets.
- Characterization of androgen receptor gene point mutations and their functional consequences.
- Investigation of nonsteroidal factors influencing AR activity.
Main Results:
- Androgen receptor gene amplification occurs in a subset of prostate cancer patients.
- Androgen receptor gene mutations can lead to functional activation by various ligands, including antihormones.
- The frequency of AR mutations may be high in tumor metastases.
- Prostate cancer cells utilize AR through various mechanisms to adapt to low androgen levels.
Conclusions:
- Alterations in androgen signaling, including AR gene amplification and mutations, are key mechanisms for endocrine therapy failure in prostate cancer.
- Prostate cancer cells exhibit adaptive strategies to maintain AR function in androgen-deprived conditions.
- Novel therapeutic approaches are required to effectively switch off androgen receptor signaling.