Chemoprevention of Prostate Cancer, HDAC Inhibition and DNA Methylation

Not Applicable

Completed

Conditions: Prostate Cancer Prevention

Interventions: Drug: SFN-rich broccoli sprout extract capsules
Dietary Supplement: Gelatin capsule containing microcrystalline cellulose.

Registration Number: NCT01265953

Lead Sponsor: Portland VA Medical Center

Brief Summary: The objective of the study is to identify mechanisms by which compounds found in cruciferous vegetables alter gene expression via epigenetic modifications (changes in gene expression) and may prevent prostate cancer development.

The investigators have found that sulforaphane (SFN), an isothiocyanate found in cruciferous vegetables, inhibits histone deacetylase (HDAC) activity in human colorectal and prostate cancer cells.

Detailed Description: Prostate cancer is the most frequently diagnosed non-cutaneous cancer and is the second leading cause of cancer death in American men. The precise etiologic factors that initiate and enhance the progression of prostate cancer remain unknown, but epigenetic alterations and diet/lifestyle factors have come forth as significant contributing factors. Epidemiologic studies suggest that cruciferous vegetable intake decreases the risk for prostate cancer. The long-term goal of this proposal is to identify mechanisms by which dietary compounds, such as those found in cruciferous vegetables decrease prostate cancer risk. The objective of the study is to identify mechanisms by which compounds found in cruciferous vegetables alter gene expression via epigenetic modifications and may prevent prostate cancer development.

The investigators have found that SFN, an isothiocyanate found in cruciferous vegetables, inhibits HDAC activity in human colorectal and prostate cancer cells.

Targeting the epigenome, including the use of HDAC and DNA methyltransferase (DNMT) inhibitors, is an evolving strategy for cancer chemoprevention and both have shown promise in cancer clinical trials.

This Randomized, Double Blind, Clinical Trial will address the following objectives:

1. Identify distribution of SFN and its metabolites and HDAC inhibition following supplementation with an SFN-rich broccoli sprout extract in subjects at risk for prostate cancer (Primary Endpoints)

2. Investigate the effects of supplementation with an SFN-rich broccoli sprout extract on DNA methylation status and proliferation markers in a pre-biopsy setting (secondary analysis)

The effects of short-term supplementation with an SFN-rich broccoli sprout extract on benign epithelial tissue will be studied in men characterized as being at risk for prostate cancer in a randomized, placebo-controlled trial. Men scheduled for prostate biopsy will be recruited into the trial.

Following successful completion of the consent, two 10 mL blood specimens for study analyses, a 4 mL specimen for total bilirubin assessment will be drawn and the subject will provide a urine sample. The study coordinator will explain the Diet History questionnaires (DHQ) and administer the risk factor and adverse event (AE) questionnaires in order to obtain data on potential confounding dietary variables and gain subjects' baseline symptoms.

The study coordinator will provide the subject with a month' supply of either an SFN-rich broccoli sprout extract (BSE) capsule which consist of 200µmol of sulforaphane (SFN) or matching placebo, as dispensed by the Research Pharmacy. The matching placebo for the BSE consists of a gelatin capsule containing microcrystalline cellulose.

Around every 2 weeks, study coordinator will call to complete AE reporting and any changes in medications or supplements and complete brief cruciferous vegetable intake checklist. Subjects will return any unused study "drug" to the study coordinator at the time of biopsy (or at the 4 week visit if subject's prostate biopsy is delayed).

Recruitment & Eligibility

Status: COMPLETED

Sex: Male

Target Recruitment: 98

Inclusion Criteria

Men scheduled for a prostate biopsy
Age 21 years or older
Signed informed subject consent

Exclusion Criteria

Definitive diagnosis with prostate cancer
Significant active medical illness which in the opinion of the investigator or clinician would preclude protocol treatment
Diagnosis of liver disease as noted on the patient problem list or baseline total bilirubin greater than institutional upper limit of normal
Subject reported allergy or sensitivity to cruciferous vegetables
Use of oral antibiotics, with the exception of doxycycline, within three months prior to randomization
Use of warfarin or need for therapeutic anticoagulation at time of biopsy or at anytime during the course of the trial.
Current oral steroid therapy
Current therapy with valproate or other pharmacological drugs associated with HDAC inhibition
Diagnosed dementia as noted on the patient problem list or other significant mental illness that may impact the subjects' ability to follow instructions or comply with the study protocol
Patient may not be a part of another flagged study
Patients already taking SFN dietary supplements

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
SFN-rich broccoli sprout extract capsules	SFN-rich broccoli sprout extract capsules	Four weeks SFN-rich broccoli sprout extract (BSE) capsules: 200µmol of sulforaphane (SFN) daily, 2 capsules (1 capsule B.I.D.) daily
Placebo capsules	Gelatin capsule containing microcrystalline cellulose.	Four weeks placebo capsules: 2 capsules (1 capsule B.I.D.) daily

Primary Outcome Measures

Name	Time	Method
Change of Total Urine SFN (Sulforaphane) Metabolites	Baseline and 4-8 weeks following intervention	Collection of blood and urine specimens occurred at pre-intervention and post-intervention. Change = post-intervention level minus pre-intervention level
Change of Total Plasma SFN (Sulforaphane) Metabolites Level	Baseline and 4-8 weeks following intervention	In subjects at risk for prostate cancer, presence of SFN was analyzed in plasma. Collection of blood specimens occurred at pre-intervention and post-intervention. The Change = post-intervention level minus pre-intervention level
Percentage of Ki67 Positive Cells up to 8 Weeks Post-randomization	Baseline and 4-8 weeks following intervention; prostate biopsy were collected post-intervention when clinically-indicated	Ki67 is a biomarker of disease progression. Immunohistochemical (IHC) analysis of Ki67 was performed using research only prostate biopsy specimens collected post-intervention at the time of the clinically-indicated prostate biopsy.
Expression of Histone Deacetylase 6 (HDAC6)	Baseline and 4-8 weeks following intervention; prostate biopsy were collected post-intervention when clinically-indicated	Immunohistochemical (IHC) analysis of HDAC6 expression using research-only prostate biopsy tissue collected post-intervention at the time of the clinically-indicated prostate biopsy. A modified Histo-score (H-score) was calculated, which involved semiquantitative assessment of both staining intensity (graded as 1-3 with 1 representing weak staining, 2 moderate, and 3 strong) and percentage of positive cells. H-score ranged from 0 to 300 with 300 the strongest expression.