Prostate cancer stem cells: a target for new therapies

Area of Science:

• Oncology
• Cancer Biology
• Stem Cell Research

Background:

• Prostate cancer treatments, largely unchanged since the mid-20th century, are often not curative.
• Current therapies target androgen receptor-expressing, proliferative cells, which constitute most tumor cells.
• Treatment resistance in prostate cancer suggests the involvement of a distinct cell population.

Purpose of the Study:

• To investigate the existence and characteristics of prostate cancer stem cells.
• To explain the observed resistance to medical therapies in prostate cancer.
• To determine if prostate cancer stem cells can initiate tumor formation.

Main Methods:

• Phenotypic characterization of prostate cancer stem cells, identifying them as basal cell-like.
• Analysis of RNA expression in cancer stem cell cultures derived from tumors versus benign tissues.
• Purification of stem cells using alpha2beta1 high integrin and CD133 markers.
• Orthotopic grafting of purified stem cells into nude mice to assess tumor-forming capacity.

Main Results:

• Prostate cancer stem cells exhibit a basal cell phenotype and do not express androgen receptor.
• Cultures derived from prostate cancers, unlike benign tissues, express prostate cancer-associated RNAs.
• Purified stem cells formed intraprostatic tumors in mice, which reexpressed androgen receptor and showed Gleason 4 histology.

Conclusions:

• Prostate cancer stem cells, characterized by specific surface markers and a quiescent, androgen receptor-negative phenotype, are likely responsible for treatment resistance.
• These stem cells possess the ability to initiate tumor formation and recapitulate the heterogeneity of the original cancer.
• Targeting prostate cancer stem cells may offer a novel therapeutic strategy for improving treatment outcomes.