Effects of Tomato Sauce Consumption on Apoptotic Cell Death in Prostate Benign Hyperplasia and Carcinoma

Abstract

Population studies have suggested that lycopene, which is mostly found in tomato and tomato products, may reduce the risk of prostate cancer. We previously found that tomato sauce consumption prior to prostatectomy for prostate cancer decreased serum prostate specific antigen, decreased oxidative DNA damage, and increased lycopene concentrations in prostate tissue (Chen et al., 2001). Here, we extended those investigations to determine whether apoptotic cell death and associated Bcl-2 and Bax proteins were modulated by tomato sauce intervention. Thirty-two patients diagnosed by biopsy with prostate carcinoma were given tomato sauce pasta entrees (30 mg lycopene/day) for 3 wk before prostatectomy. Thirty-four patients with prostate cancer who did not consume tomato sauce and underwent prostatectomy served as controls. When tumor areas with the most apoptotic cells were compared in the biopsy (before) and resected prostate tissue (after), tomato sauce consumption increased apoptotic cells in benign prostate hyperplasia (BPH) from 0.66 ± 0.10% to 1.38 ± 0.31% (P = 0.013) and in carcinomas from 0.84 ± 0.13% to 2.76 ± 0.58% (P = 0.0003). When comparable morphological areas were counted, apoptotic cell death in carcinomas increased significantly with treatment, from 0.84 ± 0.13% to 1.17 ± 0.19% (P = 0.028), and apoptotic cell death in BPH showed a tendency toward an increase from 0.66 ± 0.10% to 1.20 ± 0.32% (P = 0.20). When the values of apoptotic cells in BPH and carcinomas of patients who consume tomato sauce were compared with corresponding control lesions of the patients who did not consume tomato sauce in resected prostate tissue, the differences of values were not significant [BPH 1.38 ± 0.31% vs. 1.14 ± 0.32% (P= 0.97); carcinomas 2.76 ± 0.58% vs. 1.91 ± 0.32% (P = 0.24)]. Tomato sauce consumption did not affect Bcl-2 expression but decreased Bax expression in carcinomas. These data provide the first in vivo evidence that tomato sauce consumption may suppress the progression of the disease in a subset of patients with prostate cancer by increasing apoptotic cell death. However, because of the relatively small number of control and tomato sauce-supplemented patients and the variability in the values of apoptotic cells in BPH and carcinomas, a much larger number of patients needs to be examined to support the data generated in this study.