Structure-Activity Studies on Antiproliferative Factor (APF) Glycooctapeptide Derivatives.

Antiproliferative factor (APF), a sialylated glycopeptide secreted by explanted bladder epithelial cells from interstitial cystitis/painful bladder syndrome (IC/PBS) patients, and its unsialylated analogue (as-APF) significantly decrease proliferation of bladder epithelial cells and/or certain carcinoma cell lines in vitro. We recently reported a structure-activity relationship profile for the peptide portion of as-APF and revealed that truncation of the C-terminal alanine did not significantly affect antiproliferative activity. To better understand the structural basis for the maintenance of activity of this truncated eight amino acid as-APF (as-APF8), we synthesized several amino acid-substituted derivatives and studied their ability to inhibit bladder epithelial cell proliferation in vitro as well as their solution conformations by CD and NMR spectroscopy. While single amino acid changes to as-APF8 often strongly reduced activity, full potency was retained when the trivaline tail was replaced with three alanines. The Ala(6-8) derivative 9 is the simplest, fully potent APF analogue synthesized to date.

Structure-activity relationship studies for the peptide portion of the bladder epithelial cell antiproliferative factor from interstitial cystitis patients.

We performed comprehensive structure-activity relationship (SAR) studies on the peptide portion of antiproliferative factor (APF), a sialylated frizzled-8 related glycopeptide that inhibits normal bladder epithelial and urothelial carcinoma cell proliferation. Glycopeptide derivatives were synthesized by solid-phase methods using standard Fmoc chemistry and purified by RP-HPLC; all intermediate and final products were verified by HPLC-MS and NMR analyses. Antiproliferative activity of each derivative was determined by inhibition of (3)H-thymidine incorporation in primary normal human bladder epithelial cells. Structural components of the peptide segment of APF that proved to be important for biological activity included the presence of at least eight of the nine N-terminal amino acids, a negative charge in the C-terminal amino acid, a free amino group at the N-terminus, maintenance of a specific amino acid sequence in the C-terminal tail, and trans conformation for the peptide bonds. These data provide critical guidelines for optimization of structure in design of APF analogues as potential therapeutic agents.

Toxicokinetic study of recombinant human heparin-binding epidermal growth factor-like growth factor (rhHB-EGF) in female Sprague Dawley rats.

PURPOSE: To determine the toxicity and pharmacokinetics of recombinant heparin-binding epidermal growth factor-like growth factor in female Sprague Dawley rats following intra-bladder and intravenous administration. MATERIALS AND METHODS: rhHB-EGF was administered once daily for 6 or 27 days at doses of 3, 10, or 30 microg/kg. 125I-rhHB-EGF was administered on day 7 or 28 for pharmacokinetic analysis. Toxicity was assessed by general appearance and behavior, gross necropsy, blood chemistry and microscopic evaluation. RESULTS: Plasma AUCss of [125I] rhHB-EGF equivalents following IB administration for 7 days were 4.28+/-2.29, 7.75+/-2.70, and 7.11+/-1.42 ng ml(-1) h(-1) at doses of 3, 10, and 30 microg/kg, respectively. Following IV administration, the AUCss on day 7 increased from 27.0+/-2.66 to 124+/-5.09 and 385.11+/-7.57 ng ml(-1) h(-1) with increasing the dose from 3 to 10 and 30 microg/kg. Similar AUCss data was obtained after 28 day administration. No toxicity was evident upon gross examination. Histologic examination revealed subacute inflammation and lymphocytic infiltration of the urinary bladder in animals from all groups dosed by the IB route. CONCLUSIONS: Plasma and bladder concentrations of recombinant human [125I] rhHB-EGF equivalents were significantly lower following the IB route than following IV administration. Histologic tissue examination indicated no toxicity attributable to rhHB-EGF.

Antiproliferative factor, heparin-binding epidermal growth factor-like growth factor, and epidermal growth factor in men with interstitial cystitis versus chronic pelvic pain syndrome.

OBJECTIVES: To determine whether men with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) have urine markers previously described for patients with interstitial cystitis (IC; presence of antiproliferative factor [APF] activity, decreased levels of heparin-binding epidermal growth factor-like growth factor [HB-EGF], and increased levels of epidermal growth factor). METHODS: Clean catch urine specimens were collected from 41 symptomatic patients with CP/CPPS, 36 asymptomatic men without bladder disease who served as the control group, and 24 men with IC. APF activity was determined by (3)H-thymidine incorporation into primary normal adult human bladder epithelial cells. HB-EGF and epidermal growth factor levels were determined by enzyme-linked immunosorbent assay. RESULTS: Men with CP/CPPS did not differ significantly from asymptomatic controls for any of the three markers tested (P >0.49). In contrast, APF activity was present significantly more often and HB-EGF levels were significantly lower in the urine specimens from men with IC than in the specimens from controls or patients with CP/CPPS (P <0.00001 for all four comparisons). Although the epidermal growth factor levels also tended to be higher in the urine from patients with IC than in the urine from controls, the difference did not reach statistical significance (P = 0.06). CONCLUSIONS: These findings indicate that at least two of the urine biomarkers previously identified in women with IC (presence of APF activity and decreased levels of HB-EGF) are also found in men with IC, but not in men with CP/CPPS. This finding suggests that IC and CP/CPPS may be two different disorders with distinct pathophysiologies. It also confirms the utility of the presence of APF activity and HB-EGF levels as markers for IC in men, as well as in women, with this disorder.