Antitumor gene therapy using herpes simplex type 1 thymidine kinase (TKh) and ganciclovir (GCV) treatment has revealed an important intratumoral bystander effect. A whole tumor can be eliminated when only a fraction of its tumor cells express TKh. We now report that the bystander effect not only acts within a tumor, but also between distant tumors. One TKh+ tumor was generated simultaneously with one or multiple TKh- tumors in different rat liver lobes such that there was no contact between the resulting tumors. Both the TKh+ and the TKh- tumors regressed after GCV treatment and showed infiltration with macrophages and T lymphocytes. This distant bystander effect, which is likely immune mediated, should be of major importance for gene therapy of disseminated tumors.

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3-n-Alkylpyrroles are prepared in good yield by a combined Wolff-Kishner reduction and hydrolysis and decarboxylation of 4-acyl-2-pyrrolethiolcarboxylates. Methyl 4-isopropyl-2-pyrrolecarboxylate and 4-t-butyl-2-pyrrolecarbonitrile are prepared by alkylation of methyl 2-pyrrolecarboxylate and 2-pyrrolecarbonitrile respectively. Hydrolysis and decarboxylation of these disubstituted compounds afford the corresponding 3-alkylpyrroles. Mass spectral data for some I-, 2-, and 3-alkylpyrroles are reported.Les alkyl-3-n pyrroles sont prdpares avec un bon rendernent par rdduction de Wolff-Kishner, hydrolyse et dkarboxylation des acyl-4 pyrrolethiolcarboxylates-2. L'isopropyl-4 pyrrolecarboxylate-2 de rnkthyle et le t-butyl-4 pyrrolecarbonitrile-2 sont prepares par alkylation respectivernent du pyrrolecarboxylate-2 de rndthyle et du pyrrolecarbonitrile-2. L'hydrolyse et la dkarboxylation de ces cornposCs disubstituks conduit aux alkyl-3 pyrroles correspondants. On rapporte les donndes de spectrornktrie de rnasse pour des alkyl-1, -2, et -3 pyrroles.Canadian Journal of Chemistry, 49, 2427Chemistry, 49, (1971 Although numerous monoalkylpyrroles are known good synthetic routes to the 3-alkylpyrroles, with the possible exception of 3-methylpyrrole (1-6), are notably absent. Skell and Bean (7) have prepared numerous 3-alkylpyrroles by the alkylation of pyrrylmagnesium bromide. The low yields of 3-isomer so obtained (5-18%) together with the necessity of effecting separation from relatively large amounts (10-32%) of 2-alkylpyrrole have prompted us to devise new synthetic routes to the former compounds.We have previously shown (8) that a 2-tution to the 4-position thus methyl 2-pyrrolecarboxylate readily afforded 4-benzoyl-2-pyrrolecarboxylate which was subsequently converted to, 3-benzylpyrrole by reduction and decarboxylation.The aluminum chloride -catalyzed isopropylation (9) and t-butylation (10) of methyl 2-pyrrolecarboxylate afford the corresponding 4-alkyl-2-esters as the major kinetically controlled alkylation product. However these compounds exhibit a pronounced tendency to isomerize to the 5-alkyl-2-esters under these ethylthiolcarboxylate substituent at the pyrrole conditions preventing the use of these reactions nucleus directs Friedel-Crafts acylation and as a convenient route to the corresponding formylation almost exclusively to the 4-position. 3-alkylpyrroles. Such rearrangement is largely We now report that the resulting 2,4-substituted avoided in the gallium trichloride -catalyzed pyrroles are readily converted to-the correspond-isopropylation of the 2-ester (1 1) and by this ing 3-alkylpyrroles by a combined Wolff-method an 80% yield of methyl 4-isopropyl-2-Kishner reduction of the acyl substituent and pyrrolecarboxylate is obtained. This is readily hydrolysis and decarboxylation of the thiolester separated from the small amount (ca. 8%) of group (Scheme 1). Yields for the reaction were 5-isopropyl-2-ester and hydrolysis and decarboxylation of the former affords 3-isopropyl-pyrrole in high yield (78%).Rearr...

Suicide gene therapy based on ganciclovir (GCV) metabolism by transgene herpes simplex thymidine kinase (HSV-1 TK) has been used to selectively kill proliferating cells in clinical settings such as cancer, vascular restenosis, and immunological disorders. We investigated whether encapsulation of ganciclovir (GCV) into liposomes would improve its efficacy, especially against hepatic tumors. Large unilamellar liposomes containing GCV were prepared by reversed-phase evaporation. Pharmacokinetic studies in rats showed that, compared with free GCV, the intravenous injection of liposome-encapsulated GCV (lip-GCV) led to a faster decrease in GCV plasma concentrations, but higher liver-blood ratios. After treatment of syngeneic HSV-1 TK+ liver metastases in rats, histologically active tumors were found in 95% of the transplanted lesions when physiological saline had been given and in 50% when free GCV had been given at 90.2 microM/kg twice daily. This dose is known to be insufficient for the eradication of HSV-1 TK+ tumors. In contrast, only 5% viable tumors were found in rats receiving lip-GCV at this same concentration. Average tumor volumes were 19 +/- 15, 7 +/- 9, and <1 mm3 for the control, free GCV, and lip-GCV groups, respectively. GCV-related toxicity was no longer observed. The results demonstrate that liposomal encapsulation of GCV is feasible and significantly enhances its efficacy against HSV-1 TK+ hepatic tumors.

Syntheses of derivatives of the isomeric 4-amino-? ,3,4,5-tetrahydrobenz[cd]indol-5-ols (1) and (6) and the structurally similar 4-amino-2a,3,4,5-tetrahydroacenaphthen-5-ols ( 2 2 ) and (28), and of certain N-alkyl and NN-dimethyl derivatives are described. Preparation of the tetrahydrobenz[cd] indole series was made possible by the use of the tosyl group for protection of the indole imino-group.