No abstract

A high degree of variability in the definition of biochemical recurrence exists following treatment for localized prostate cancer. Strict definitions for biochemical recurrence are necessary to identify men at risk for disease progression and to allow meaningful comparisons among patients treated similarly. The Panel acknowledges the American Society for Therapeutic Radiology and Oncology criteria and future modifications thereof for those receiving radiation therapy and recommends the newly developed American Urological Association criteria for those treated with radical prostatectomy. The purpose for the establishment of this standard is for data reporting purposes and for comparison of similarly treated patients. It is not intended to represent a threshold value for which to initiate treatment. The Panel acknowledges that the clinical decision to initiate treatment will be dependent on multiple factors including patient and physician interaction rather than a specific prostate specific antigen threshold value.

During fetal prostate development, Sonic hedgehog (Shh) expression by the urogenital sinus epithelium activates Gli-1 expression in the adjacent mesenchyme and promotes outgrowth of the nascent ducts. Shh signaling is down-regulated at the conclusion of prostate ductal development. However, a survey of adult human prostate tissues reveals substantial levels of Shh signaling in normal, hyperplasic, and malignant prostate tissue. In cancer specimens, the Shh expression is localized to the tumor epithelium, whereas Gli-1 expression is localized to the tumor stroma. Tight correlation between the levels of Shh and Gli-1 expression suggests active signaling between the tissue layers. To determine whether Shh-Gli-1 signaling could be functionally important for tumor growth and progression, we performed experiments with the LNCaP xenograft tumor model and demonstrated that: 1). Shh expressed by LNCaP tumor cells activates Gli-1 expression in the tumor stroma, 2). genetically engineered Shh overexpression in LNCaP cells leads to increased tumor stromal Gli-1 expression, and 3). Shh overexpression dramatically accelerates tumor growth. These data suggest that hedgehog signaling from prostate cancer cells to the stroma can elicit the expression of paracrine signals, which promote tumor growth.

No abstract

Prostate cancer is the second leading cause of cancer death in the United States and, thus far, there has been no effective therapy for the treatment of hormonerefractory disease. Recently, the androgen receptor (AR) has been shown to play a critical role in the development and progression of the disease. In this report, we showed that knocking down the AR protein level by a small interfering RNA (siRNA) approach resulted in a significant apoptotic cell death as evidenced by an increased annexin V binding, reduced mitochondrial potential, caspase-3/6 activation, and DFF45 and poly(ADP-ribose) polymerase cleavage.