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Updated: Apr 18, 2026
RhoC GTPase Activation Assay
Published on: August 22, 2010
Inhibition of prostate smooth muscle contraction and prostate stromal cell growth by the inhibitors of Rac, NSC23766
Y Wang1,2, T Kunit1,3, A Ciotkowska1
1Department of Urology, Ludwig Maximilian University, Munich, Germany.
Background And Purpose:
Medical therapy of lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH) targets smooth muscle contraction in the prostate, or prostate growth. However, current therapeutic options are insufficient. Here, we investigated the role of Rac in the control of smooth muscle tone in human prostates and growth of prostate stromal cells.
Experimental Approach:
Experiments were performed using human prostate tissues from radical prostatectomy and cultured stromal cells (WPMY-1). Expression of Rac was examined by Western blot and fluorescence staining. Effects of Rac inhibitors (NSC23766 and EHT1864) on contractility were assessed in the organ bath. The effects of Rac inhibitors were assessed by pull-down, cytotoxicity using a cell counting kit, cytoskeletal organization by phalloidin staining and cell growth using an 5-ethynyl-2'-deoxyuridine assay.
Key Results:
Expression of Rac1-3 was observed in prostate samples from each patient. Immunoreactivity for Rac1-3 was observed in the stroma, where it colocalized with the smooth muscle marker, calponin. NSC23766 and EHT1864 significantly reduced contractions of prostate strips induced by noradrenaline, phenylephrine or electrical field stimulation. NSC23766 and EHT1864 inhibited Rac activity in WPMY-1 cells. Survival of WPMY-1 cells ranged between 64 and 81% after incubation with NSC23766 (50 or 100 μM) or EHT1864 (25 μM) for 24 h. NSC23766 and EHT1864 induced cytoskeletal disorganization in WPMY-1 cells. Both inhibitors impaired the growth of WPMY-1 cells.
Conclusions And Implications:
Rac may be a link connecting the control of prostate smooth muscle tone with proliferation of smooth muscle cells. Improvements in LUTS suggestive of BPH by Rac inhibitors appears possible.
Insights
Rac inhibitors show potential for treating benign prostatic hyperplasia (BPH) by reducing prostate smooth muscle contraction and stromal cell growth. This study investigated Rac
Area of Science:
- Urology
- Cell Biology
- Pharmacology
Background:
- Current medical therapies for lower urinary tract symptoms (LUTS) in benign prostatic hyperplasia (BPH) are insufficient.
- Therapeutic strategies primarily target prostate smooth muscle contraction or growth.
Purpose of the Study:
- Investigate the role of Rac proteins in regulating human prostate smooth muscle tone.
- Examine the impact of Rac on prostate stromal cell growth.
Main Methods:
- Western blot and immunofluorescence staining to detect Rac expression in human prostate tissues and WPMY-1 cells.
- Organ bath studies to assess the effects of Rac inhibitors (NSC23766, EHT1864) on prostate tissue contractility.
- In vitro assays to evaluate Rac activity, cell viability, cytoskeletal organization, and proliferation in response to Rac inhibitors.
Main Results:
- Rac1-3 expression was confirmed in human prostate stroma, co-localizing with the smooth muscle marker calponin.
- Rac inhibitors significantly reduced prostate tissue contractions induced by various stimuli.
- Inhibition of Rac activity by NSC23766 and EHT1864 led to cytoskeletal disorganization and impaired proliferation of WPMY-1 cells, with moderate cytotoxicity.
Conclusions:
- Rac signaling plays a crucial role in both prostate smooth muscle contractility and smooth muscle cell proliferation.
- Rac inhibitors represent a promising therapeutic avenue for improving LUTS associated with BPH.
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