Combinatorial synthesis and screening of a chemical library of 1,4-dihydropyridine calcium channel blockers.

Solid-phase synthesis of a 300-member pharmacophore library of 1,4-dihydropyridines from keto ester, diketone and aldehyde building blocks on a cleavable amine polymeric support is described. Screening and serial deconvolution of the combinatorial library has resulted in identification of known and new potent calcium channel blockers.

Gene therapy of metastatic pancreas cancer with intraperitoneal injections of concentrated retroviral herpes simplex thymidine kinase vector supernatant and ganciclovir.

OBJECTIVE: The objective of this study was to determine the efficacy of intraperitoneal (IP) injections of a new concentrated herpes simplex thymidine kinase (HS-tk) retroviral vector and ganciclovir (GCV) for peritoneal metastases from pancreas cancer. SUMMARY BACKGROUND DATA: Metastatic pancreas cancer is fatal. Gene therapy may provide a novel approach for this disease. Gene therapy with adeno- or retroviral-mediated transfer of the HS-tk gene into tumor cells renders the cells susceptible to GCV. Intratumoral or intracavity injections of retroviral vectors have been ineffective in previous studies. METHODS: Pancreatic cancer B x PC3 cells (3 x 10(7)) were injected into the tail of pancreas in nude mice. Mice received IP injections of a concentrated HS-tk vector (5 x 10(7)) cfu/mliters) or a control vector (G1Na) without the tk gene for 10 days and GCV (100 mg/kg) for 14 days. To determine whether the vector would survive in the milieu of the peritoneal cavity, the authors examined the effects of ascitic fluid on the vector. Pancreas cancer cells were transduced in vitro with HS-tk vector in presence of media or ascitic fluid and treated with GCV. RESULTS: Highly significant reductions in the mass of metastatic peritoneal tumor deposits were found in HS-tk-treated group (124 +/- 27 mg; n = 11) compared with G1Na vector controls (910 +/- 168 mg; n = 8; p < 0.0001). Results of polymerase chain reaction analysis demonstrated integration of the vector in the tumors, and on immunohistochemistry, expression of the TK protein was seen in the number of surviving colonies (representing nontransduced cells) were similar in both groups, suggesting that the vector effectively transduced tumor cells bathed in the ascitic fluid. CONCLUSIONS: Results demonstrate that IP administration of concentrated retroviral HS-tk vectors is effective treatment for pancreas cancer metastatic to the peritoneal cavity; furthermore, the vector is active in the presence of ascitic fluid. Intraperitoneal retroviral HS-tk may provide a novel approach to treatment of metastatic pancreas cancer.

Enhanced expression of factor XII (Hageman factor) in isolated livers of estrogen- and prolactin-treated rats.

Estrogens and prolactin may raise the plasma titer of factor XII (Hageman factor) by enhancing gene expression at the level of transcription and RNA processing, protein synthesis, or secretion (or a combination of these). Alternatively, these hormones may protect factor XII or its transcripts from degradation. Because the liver is a major site of factor XII synthesis, we studied the expression and metabolism of factor XII in isolated livers of estrogen- and prolactin-treated rats. All rats were ovariectomized to reduce the effect of endogenous estrogen and prolactin on the expression of factor XII. When a phosphorus 32-labeled factor XII complementary DNA probe for Northern blot analysis was used, increased factor XII messenger RNA was found in poly (A) RNA prepared from livers of estrogen- and prolactin-treated rats relative to those of untreated rats. Simultaneously, enhanced release of immunoreactive factor XII was noted when isolated liver perfusion techniques were used. Cycloheximide, an inhibitor of protein synthesis, blocked the hepatic release of immunoreactive factor XII in both hormone-treated and untreated rats, suggesting that factor XII translation was directly affected. The biologic half-life of injected rat iodine 125-labeled factor XII in estradiol- and prolactin-treated rats was not significantly different from that in untreated rats. By inference from these data, the high plasma titer of factor XII observed in estrogen- and prolactin-treated rats is caused by enhanced hepatic expression at both transcriptional and translational levels, as well as by increased secretion of factor XII.