Growth support of small B16 melanoma implants with nitrosourea-sterilized fractions of the same tumor.

B16 melanoma cells sterilized in vitro with 1,3-bis(2-chloroethyl)-1-nitrosourea or in vivo with trans-1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea, have been used to enhance the percentage of tumor takes with small s.c. implants of viable cells and to reduce the latent period between tumor implantation and palpability. The admixture of trans-1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea-inactivated cells with viable cell implants reduced the number of cells required to produce tumors in 50% of the animals by approximately 3 log10 units and markedly reduced the time of tumor appearance from implants of up to 10(6) cells. Similar results were obtained with 1,3-bis(2-chloroethyl)-1-nitrosourea-sterilized cells. The growth-supporting effect obtained with the nitrosourea-inactivated cells appeared to be as pronounced as that previously reported, for this tumor system, with radiation-inactivated cells.

Metabolism and chemotherapeutic activity of 9-beta-D-arabinofuranosyl-2-fluoroadenine against murine leukemia L1210 and evidence for its phosphorylation by deoxycytidine kinase.

The 2-fluoro derivative of 9-beta-D-arabinofuranosyladenine (2-F-ara-A) and its soluble 5'-formate and 5'-phosphate derivatives were therapeutically effective against the parent leukemia L1210 (L1210/0). 2-F-ara-A and 9-beta-D-arabinofuranosyladenine 5'-formate were inactive aginst a 1-beta-D-arabinofuranosylcytosine-resistant subline (L1210/ara-C) that was deficient in deoxycytidine kinase. Deoxycytidine prevented 2-F-ara-A-induced inhibition of proliferation of L1210/0 cells in culture and alleviated 2-F-ara-a inhibition of DNA synthesis. After treatment of mice with 9-beta-D-arabinofuranosyladenine 5'-formate, intracellular levels of the 5'-triphosphate of 9-beta-D-arabinofuranosylfluoroadenine in leukemia cells were more than 10 times higher in L1210/0 cells than in L1210/ara-C cells. Similar results were obtained in this line of leukemia cells from mice treated with the 5'-monophosphate of 9-beta-D-arabinofuranosyl-2-fluoroadenine. Thus, L1210/ara-C cells deficient in deoxycytidine kinase activity were also deficient in capacity to phosphorylate 2-F-ara-A. Kinase activity from L1210/0 cells for deoxycytidine and for 2-F-ara-A coeluted from calcium phosphate cellulose and from diethylaminoethyl cellulose columns and had similar mobility on gel electrophoresis. Deoxyadenosine kinase was clearly separated from deoxycytidine kinase. Deoxycytidine competed with 2-F-ara-A for phosphorylation by the partially purified enzyme from L1210 cells. These results indicate that 2-F-ara-A is phosphorylated to the 5'-monophosphate by deoxycytidine kinase of leukemia L1210 cells.

Cyclophosphamide-adriamycin combination chemotherapy of transplantable murine tumors.

The two-drug combination of cyclophosphamide plus adriamycin was found to be therapeutically potentiating against four different C3H mammary tumor lines, the B16 melanoma, the Ridgway osteogenic sarcoma, and the P388 leukemia. The potentiation was not schedule dependent.

Tumor induction relationships in development of transplantable cancers of the colon in mice for chemotherapy assays, with a note on carcinogen structure.

In an effort to establish an animal colon tumor model suitable for biological and chemotherapy studies, 82 colon tumors were induced and transplanted in four different inbred strains of mice. Four colon tumors survived the first transplant and are now in serial passage. All are suitable for chemotherapy trials. Two tumors are highly metastatic, and at least one of these is known to be suitable for surgery-chemotherapy adjuvant studies. The effective colon carcinogens contained a (see article) molecular similarity.

Induction and chemotherapeutic response of two transplantable ductal adenocarcinomas of the pancreas in C57BL/6 mice.

Following implant of cotton thread-carrying 3-methyl-cholanthrene into the pancreas tissue of 90 C57BL/6 and 60 BALB/c mice, 13 developed ductal adenocarcinomas. Two of these tumors, both of C57BL/6 origin (Panc 02 and 03), were established in serial s.c. transplant. Panc 02 was treated with 37 different anticancer drugs representing all of the chemical and functional classes of clinically useful anticancer agents including alkylating agents, antimetabolites, agents that bind to or cause scission of DNA, and others that inhibit mitosis or inhibit protein synthesis. When drug treatment was started within 3 to 4 days after tumor implant, Panc 02 showed only limited response to treatment with two nitrosoureas, [N'-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-N-(2-chloroethyl)-N- nitrosourea, monohydrochloride and N-(2-chloroethyl)-N'-(2,6-dioxo-3-piperdinyl)-N-nitrosourea)], and N-phosphonacetyl-L-aspartate. Drug response of Panc 03 was determined only with Adriamycin, 5-fluorouracil, cyclophosphamide, cis-(SP-4-2)-diamminedichloroplatinum, or N,N'-bis(2-chloroethyl)-N-nitrosourea. When drug treatment was started 3 days after tumor implant, high cure rates were obtained with Adriamycin treatment, and limited therapeutic responses were seen to treatment with cis-diamminedichloroplatinum or cyclophosphamide. A comparison of the biological characteristics and drug responsiveness of Panc 02 and Panc 03 with those of a number of other transplantable tumors of mice is reported.

Toxicity and anticancer activity of a new triazine antifolate (NSC 127755).

A new triazine folate antagonist, 3-chloro-4-((4-(2-chloro-4-[4,6-diamino-2,2-dimethyl-s-triazin-1(2H)-yl]phenyl)butyl)) benzenesulfonyl fluoride compounded with ethanesulfonic acid (1:1) (NSC 127755), was highly active against four transplantable colon adenocarcinomas (36, 38, 10/A, 12/A) and the Dunning murine ovarian tumor M5076. Treatment schedule studies indicated that a prolonged time of exposure provided optimum antitumor activity for the compound. The combination of NSC 127755 plus 4-amino-1-[5-O-(1-oxohexadecyl)-beta-D-arabinofuranosyl]-2(1H)-pyrimidinone (palmO-ara-C, NSC 135962) was found to have therapeutic synergism against grossly evident colon adenocarcinoma 36.

The mechanism of action of 3-deazauridine in tumor cells sensitive and resistant to arabinosylcytosine.

Deazauridine inhibited growth of tumor cells in culture and in culture and in vivo; this agent was significantly more effective against L1210/AraC than against the parent sensitive line. Inhibition of growth of tumor cells in culture was prevented by uridine and cytidine and was partially alleviated by deoxycytidine, but not by deoxyuridine or thymidine. DeazaUR inhibited nucleic acid synthesis but not protein synthesis in tumor cells in culture; deoxycytidine alleviated inhibition of nucleic acid synthesis. The labeling of pyrimidine ribonucleotides by 6-14C-orotic acid was inhbited by deazaUR. DeazaUR treatment of tumor cells in culture resulted in increased uptake of cytidine-3H into RNA, whereas uridine-3H uptake into RNA was inhibited. Labelling of DNA by uridine-3H/ and cytidine-H was inhibited by deazaUR. Pools of CMP, CDP, and CTP decreased markedly during deazaUR treatment of L1210 cells in culture and in vivo. These observations in growing cells pointed to deazaUR inhibition of the synthesis of cytidylic acid. Deazauridine 5'-triphosphate was found to be an inhibitor of the synthesis of CTP from UTP catalyzed by enzyme preparations from L1210 cells. This observation is in agreement with those of McPartland et al.19 that deazaUTP inhibited CTP synthetase purified from calf liver. Deazauridine treatment of L1210 cells in culture stimulated the uptake of deoxycytidine-3H into DNA while inhibiting the uptake of 3H-labeled deoxyuridine, thymidine, deoxyadenosine, and deoxyguanosine. Intracellular pools of dCTP were decreased by deazauridine treatment in L1210 cells in culture and in vivo. Deazauridine 5'-diphosphate inhibited the enzymatic reduction of pyrimidine ribonucleoside 5'-diphosphates to the corresponding deoxyribonucleotides. These results are consistent with the view that deazauridine, after its uptake and intracellular phosphorylation, strongly inhibits the formation of CTP. This is considered to be the primary metabolic effect of the analog. A secondary effect appears to be an inhibition of dCTP formation.

Absence of delayed lethality in mice treated with aclacinomycin A.

Two compounds that bind to or intercalate with DNA (DNA binders), e.g., adriamycin and 'dihydroxyanthracenedione', 9,10-anthracenedione, 1,4-dihydroxy-5,8-bis[[2-[(2-hydroxyethyl)-amino]ethyl]amino]-, dihydrochloride salt, consistently caused delayed lethality (20-200 days after treatment) if administered intraperitoneally (IP). Both of these agents contain para-hydroxyl groups in the ring adjacent to the quinone ring. Certain analogs of these compounds (aclacinomycin A and 'anthracenedione acetate', 9,10-anthracenedione, 1,4-bis[[2-[(2-hydroxyethyl)amino]ethyl]amino]-, diacetate (salt), which do not contain para-hydroxyl groups, did not cause delayed deaths when injected IP. The only difference in the molecular structure (other than the nature of their amine salts) between dihydroxyanthracenedione and anthracenedione acetate lies in the para-hydroxyl groups in the ring adjacent to the quinone ring. Another compound that binds to DNA, m-AMSA, which has neither the quinone function nor the para-hydroxyl groups, did not cause delayed deaths after IP administration.