Growth inhibition by 8-chloro cyclic AMP of human HT29 colorectal and ZR-75-1 breast carcinoma xenografts is associated with selective modulation of protein kinase A isoenzymes

Significant dose-related inhibition of growth of HT29 human colorectal cancer xenografts and ZR-75-1 breast cancer xenografts in immune-suppressed mice was induced by the cyclic AMP analogue, 8-chloroadenosine 3',5'-cyclic monophosphate (8-Cl-cyclic AMP) when given by alzet mini-pumps over a 7-day period at doses of either 50 or 100 mg/kg/day. Levels and types of cyclic AMP binding proteins were measured by ligand binding and photoaffinity labelling, respectively, in tumours harvested at the end of the treatment period. Compared with levels in tumours from control animals, values of tumour cyclic AMP binding proteins from treated animals were significantly reduced. These effects were associated with an apparent modulation of the types of cyclic AMP binding proteins, 8-Cl-cyclic AMP-treated xenografts displaying a reduced ratio of RI/RII isoforms compared with untreated control tumours.

Biological relationships among the Iroquois

The intrusive cultural and linguistic position of Iroquoian-speaking peoples among Algonquian speakers of the lower Great Lakes region has sparked much debate concerning their cultural and biological origins. Previous physical anthropological studies, largely limited to typological or univariate osteometric analyses, have produced equivocal and contradictory results, offering little insight into the question of origins. This study addresses the question of Iroquois origins by examining biological relationships in the lower Great Lakes region using a multivariate analysis of anthropometric data. The study uses 12 body and head measurements taken on 843 individuals from 7 Iroquoian and 4 Algonquian groups. The data were examined using biodistances, canonical variate analysis, and a model of differential gene flow. The results indicate a possible biological distinction between Iroquoians and Algonquians, suggesting different biological origins. Gene flow in prehistoric and historical times may have mitigated much of this differentiation. The Onondaga most closely approximate the ancestral Iroquoian phenotype and are phenotypic outliers, probably because of reproductive isolation from the Algonquians. The Onondaga have unexpectedly high mean phenotypic variance with respect to distance from the phenotypic centroid, suggesting a greater than average degree of external gene flow. Because no viable source for external genes can be determined, however, the Onondaga's high mean variance may be better explained through patterns of nonrandom mating and reproductive isolation.

Processing of the neuropeptide growth factor antagonist [Arg6, D-Trp7.9, NmePhe8]-substance P (6-11) by a small cell lung cancer cell line (H69)

[Arg6, D-Trp7.9, NmePhe8]-substance P (6-11) (antagonist G) is a broad spectrum neuropeptide growth factor antagonist about to enter clinical trials as an anticancer drug. Its fate has been studied after incubation with two densities (5 x 10(4) cells/mL and 1 x 10(6) cells/mL) of the H69 small cell lung cancer cell line for up to 7 days at a concentration of 20 microM, corresponding to the IC50 for growth inhibition. HPLC analyses were conducted on cell pellets and media and in controls consisting of cell free media and water. Over 7 days in media containing cells a 70.4% reduction in parent peptide concentration occurred at the high density and a 44.1% reduction at low density. Despite this, there was a steady elevation in peptide associated with cells reaching a 189% increase by day 7. Oxidation of G at the C-terminal methionine residue occurred in all media studied indicative of a chemical process. The two major active metabolites of antagonist G (deamidated G and G minus Met11) were detected only in media in the presence of cells. These accumulated with time in media and cells together with oxidized products. These results reveal complex cellular pharmacology for antagonist G where H69 cells are increasingly exposed to 4 different peptide products rather than 1.

c-erbB-3 protein expression in ovarian tumours

In this study the expression of c-erbB-3 protein was investigated in a range of human ovarian tumours using a monoclonal antibody (RTJ1) raised to a synthetic peptide from the cytoplasmic domain of the human c-erbB-3 protein. A total of 73 samples from 71 patients were graded as negative, weak, moderate or strong according to the intensity of immunohistochemical staining observed, and this was related to tumour characteristics and other clinical parameters. In terms of positivity vs negativity, of the 73 samples examined, 62 (85%) showed positive immunohistochemical staining for c-erbB-3. The majority of all ovarian tumours studied were positive for c-erbB-3 regardless of whether they were malignant (89%), borderline (100%) or benign (61%), however the incidence of positivity was significantly less in the benign group than in overtly malignant tumours (P = 0.03). c-erbB-3 positivity was not significantly associated with either age at diagnosis, tumour stage, differentiation, ploidy, percentage in S-phase or post-operative tumour bulk in malignant tumours. In terms of intensity of staining no significant difference was observed either within the common epithelial group or between this group and tumours of a benign nature. A significantly more intense pattern of c-erbB-3 staining was observed in tumours of borderline malignancy when compared with their overtly malignant counterparts (P = 0.002). Patients presenting with early-stage malignant tumours (I/II) were more likely to display intense tumour staining than those with late-stage disease (III/IV) (P = 0.04). These investigations suggest that c-erbB-3 protein is frequently expressed in both benign and malignant ovarian tumours, and that overexpression is more common in borderline and early invasive lesions.

Metabolism of the anticancer peptide H-Arg-D-Trp-NmePhe-D-Trp-Leu-Met-NH2

H-Arg-D-Trp-NmePhe-D-Trp-Leu-Met-NH2 (Antagonist G) will be the first broad-spectrum neuropeptide antagonist to enter a phase I clinical trial. Its in vitro and in vivo metabolism has been extensively characterized. The major metabolites were identified and their structures elucidated by mass spectroscopy and amino acid analysis. Metabolism occurred almost exclusively at the C-terminus and was arrested by phenylmethylsulfonylfluoride, a known serine-protease inhibitor. Biological characterization of the metabolites demonstrated that the degradation of Antagonist G produces metabolites that retain neuropeptide antagonist properties.

The regulation of growth and protein expression by estrogen in vitro: a study of 8 human ovarian carcinoma cell lines

The effects of 17 beta-estradiol (E2) on the growth and the levels of estrogen receptor (ER), progesterone receptor (PR) and pS2 protein were examined in a range of 8 ovarian carcinoma cell lines. E2 stimulated growth of the 3 cell lines with an ER content of 80-220 fmol/mg protein but not the 5 cell lines with ER concentrations less than 20 fmol/mg protein. After exposure to E2, ER concentration in 2 of the 3 responsive cell lines was decreased relative to untreated cells and in 2 lines, progesterone receptors were increased. No change in steroid receptor levels was observed in cell lines with low or negligible levels of receptors. The pS2 protein was not induced by E2 in the 5 ovarian carcinoma cell lines examined. These results indicate that E2 can stimulate the growth of some ER-positive ovarian carcinoma cells and that these effects may be associated with changes in the cellular levels of steroid hormone receptors.

Stability and in vitro metabolism of the mitogenic neuropeptide antagonists [D-Arg1,D-Phe5, D-Trp7,9, Leu11]-substance P and [Arg6, D-Trp7,9, MePhe8]-substance P (6-11) characterized by high-performance liquid chromatography

The substance P (SP) analogues [D-Arg1, D-Phe5, D-Trp7,9, Leu11]-SP and [Arg6, D-Trp7,9, MePhe8]-SP (6-11) (antagonists D and G, respectively) are under consideration as new anticancer drugs. In this report, the stability and in vitro metabolism of both antagonists in up to seven different media (water, 1 M acetic acid, human plasma, nude mouse liver and WX 322 human SCLC xenograft homogenized in either 1 M acetic acid or phosphate buffered saline (PBS), pH 7.4) have been characterized by both isocratic and gradient elution reversed-phase HPLC. Antagonist D was stable (never > 13% degradation over 24 h, at 37 degrees C) in water, 1 M acetic acid and plasma but was metabolized by PBS liver homogenates (10%, w/v) sequentially to two stable metabolites with a half life of 0.98 h at a concentration of 500 micrograms ml-1. The major pathway of degradation of antagonist G appeared to be C-terminal methionine oxidation (particularly in plasma) as well as hydrolysis, with even aqueous solutions being significantly affected at low concentrations of peptide (0.1 micrograms ml-1, half life 20.9 h at 37 degrees C). Stable metabolites of antagonist G were also detected in incubations with PBS liver homogenates (half life 1.53 h at 500 micrograms ml-1, 37 degrees C). Overall, the data presented indicate that the modifications made to SP have been relatively successful in preserving chemical and biological stability.

Preclinical phase II studies in human tumor xenografts: a European multicenter follow-up study

BACKGROUND

The EORTC New Drug Development Office has initiated a multicenter collaborative program to evaluate the use of human tumor xenografts to predict phase II clinical activity. A first study confirmed the efficacy of doxorubicin and inactivity of amsacrine against human tumor xenografts (Boven et al., Cancer Res: 52, 5940, 1992). In the follow-up study reported here, the activities of cisplatin, AZQ (diaziquone), pazelliptine and retelliptine have been evaluated against a panel of 40 established tumor lines grown subcutaneously in nude mice.

DESIGN

The xenografts used represent carcinomas of the breast, colon, head+neck, ovary, small cell lung cancer (SCLC), non-small cell lung cancer (NSCLC) and melanoma. Drugs were administered intravenously on days 0 and 7. Doses were for cisplatin 5 mg/kg, AZQ 3-7 mg/kg, pazelliptine 20-80 mg/kg and retelliptine 6-12.5 mg/kg and were selected to give a median loss of about 10%-15% body weight.

RESULTS

When activity was defined as a specific growth delay > 1 and a tumor growth inhibition > 50%, then cisplatin demonstrated activity in 15 of 40 xenografts tested (3 of 5 breast, 1 of 6 colon, 0 of 5 head+neck, 2 of 6 NSCLC, 4 of 7 SCLC, 1 of 5 melanoma and 4 of 6 ovarian cancers); AZQ was active in 23 of 38 xenografts (2 of 3 breast, 2 of 7 colon, 4 of 5 head+neck, 3 of 6 NSCLC, 6 of 6 SCLC, 2 of 5 melanoma, 4 of 6 ovarian cancers); pazelliptine was active in 2 of 38 xenografts (1 of 5 breast cancers, 1 of 5 melanoma) while retelliptine was active in 1 of 39 xenografts (a breast cancer xenograft) tested.

CONCLUSIONS

These results are reasonably consistent with the clinical activity of cisplatin, but overpredict the clinical efficacy of AZQ. Since pazelliptine and retelliptine are investigational compounds, the clinical phase II studies will provide a prospective test for this model. The results of the present study and the previous one indicate that the human tumor xenograft model could be suitable for predicting the activity of novel compounds to be developed for treatment of cancer patients.

Determination of two neuropeptide growth factor antagonists, [D-Arg1,D-Phe5,D-Trp7,9,Leu11]-substance P and [Arg6,D-Trp7,9,N-MePhe8]- substance P(6-11), by high-performance liquid chromatography with electrochemical detection

The neuropeptide growth factor antagonists [D-Arg1,D-Phe5,D-Trp7,9,Leu11]-substance P (D) and [Arg6,D-Trp7,9, [corrected] N-MePhe8]-substance P(6-11) (G) are currently undergoing preclinical evaluation as potential anticancer agents and clinical trials are planned for G in the near future. A reversed-phase high-performance liquid chromatographic separation has been developed which is both sensitive (limit of detection 250 pg/263 fmol for G; 500 pg/330 fmol for D) and selective, based on electrochemical detection of the two tryptophan residues present in each peptide. Two ion-pairing agents were included in the isocratic mobile phase to eliminate adsorption of the peptides onto the analytical column. Extensive sample clean-up procedures have been developed for plasma, tissue and tumour based on solid-phase extraction. Precision and accuracy of each assay was 91.3 +/- 16.9% (between-day) for G and 99.3 +/- 16.9% (between-day) for D. The assays were able to detect the intact peptides and a number of their metabolites in plasma, liver and the WX 322 SCLC human xenograft in nude mice for at least 6 hr after administration of therapeutic and pharmacological doses.

Growth inhibition of oestrogen receptor-positive human ovarian carcinoma by anti-oestrogens in vitro and in a xenograft model

This paper presents results of the in vitro and in vivo effects of anti-oestrogens on the growth of human ovarian cancer cells. Tamoxifen and the "pure" anti-oestrogens, ICI 164,384 and ICI 182,780, inhibited the oestrogen-stimulated growth of the oestrogen receptor (ER)-positive PE04 and PE01 cell lines grown in culture, the latter two compounds being more potent than tamoxifen. In the absence of 17 beta-oestradiol (E2), tamoxifen, but not the pure anti-oestrogens, produced a small degree of growth stimulation in the PE01 and PE04 lines at concentrations between 10((7) and 10(-9) M. In contrast, growth of the ER-negative PE014 line was unaffected by E2 and all three anti-oestrogens. The effects of tamoxifen and ICI 182,780 on PE04 cells grown as xenografts in nude mice were also studied. Both anti-oestrogens produce significant growth inhibitory effects. These results indicate that ovarian carcinoma cells may be sensitive to anti-oestrogens in vitro and in vivo, and support the view that anti-oestrogens merit further clinical studies in patients with ER-positive tumours.

Contrasting effects of 17 beta-estradiol on the growth of human ovarian carcinoma cells in vitro and in vivo

A human ovarian adenocarcinoma cell line (PE04) has been established as a xenograft in nude mice. In vitro, this cell line is estrogen receptor (ER)-positive and its growth is stimulated by 17 beta-estradiol at concentrations between 10(-12) and 10(-6) M. When xenografted, PE04 cells remain ER-positive and also possess progesterone receptors (PR); treatment with 17 beta-estradiol reduces the concentration of ER and increases levels of PR. Growth of the xenograft is reduced in ovariectomized animals while implantation of estrogen pellets also results in growth inhibition. Similar treatment with estrogen does not inhibit the ER-negative HOX 60 ovarian xenograft, and stimulates growth of the ER-positive ZR-75-I breast carcinoma xenograft. Serum measurements of 17 beta-estradiol confirm that ovariectomy reduces the level of 17 beta-estradiol while implantation of estrogen pellets results in raised levels of the hormone. Tamoxifen inhibits growth of the PE04 xenograft but not that of the HOX 60 xenograft, consistent with ER status. These results indicate that ER-positive PE04 ovarian cancer cells are sensitive to 17 beta-estradiol in vivo but that the response may be of a different type from the in vitro response. This lends further support to the concept that ovarian cancer may be hormone-sensitive and potentially responsive to endocrine therapy.

12-O-tetradecanoylphorbol 13-acetate induced differentiation in human lung squamous carcinoma cells

Three human lung squamous carcinoma cell lines (NX002, CX140 and CX143) demonstrate features of squamous differentiation including involucrin synthesis and competence to form cornified envelopes. 12-O-Tetradecanoylphorbol 13-acetate inhibits growth of these cell lines and this growth inhibition is associated with enhanced differentiation.

The influence of type I collagen on the growth and differentiation of the human colonic adenocarcinoma cell line HT-29 in vitro

HT-29 Human colonic adenocarcinoma cells when grown on a plastic substratum were anaplastic in appearance and failed to express any morphological or biochemical features that were characteristic of intestinal differentiation. Growth of HT-29 cells subcutaneously in the flank of immune deprived mice gave rise to morphologically heterogeneous tumors which were poorly differentiated but contained approximately 11% of cells with an intestinal phenotype: these showed features typical of cell polarization with well-developed microvilli, tight junctional complexes and desmosomes between adjacent cells. The transfer of cells from plastic onto either a fixed (designated 'non-released') or floating (designated 'released') type I collagen gel induced some morphological features typical of intestinal differentiation; for example goblet-like cells were observed after 9 days, but biochemical markers of differentiation were expressed only modestly. The continued subculture of HT-29 cells on collagen type I gels, which were either attached to the plastic or floating in the medium, induced some morphological features of intestinal differentiation and changes in the activity of brush border-associated enzymes. Alkaline phosphatase activity was enhanced from 1.3 x 10(-3) mumoles/mg/min for cells cultured on plastic substrata to 2.1 x 10(-3) mumoles/mg/min when gels were non-released, and 2.9 x 10(-3) mumoles/mg/min when gels were released after 12 days of culture. This was confirmed by electron microscopical visualization of alkaline phosphatase activity. Elevated levels of aminopeptidase activity were also observed on day 12 (plastic = 26 milliunits/mg; non-released gel = 41 milliunits/mg; released gel = 36 milliunits/mg). Similarly, changes occurred in the secretion of carcinoembryonic antigen from 0.96 x 10(-2) micrograms/mg/48 hours by cells cultured on plastic to 2.3 x 10(-2) micrograms/mg/48 hours by cells cultured on floating collagen gels. The effects of permitting HT-29 cells to undergo polarization were tested by culture on inert filter inserts: morphological features of intestinal differentiation were observed although this did not occur until after 21 days. These studies show that optimization of the growth conditions of anaplastic cells in vitro may provide cultures more representative of the tumor in vivo. This model system may be useful for cell biological and pharmacological studies of colon carcinoma.

Growth control by epidermal growth factor and transforming growth factor-alpha in human lung squamous carcinoma cells

Although EGF receptor expression is generally elevated in human lung squamous carcinoma, the biological significance of this phenomenon and the role of EGF and TGF-alpha in this disease are poorly understood. We have investigated three human lung squamous carcinoma cell lines (NX002, CX140 and CX143) and have shown, using an antibody (EGFR1) directed against the EGF receptor, that the majority of cells in all three lines express the EGF receptor. Using a ligand binding assay, Scatchard analysis indicated high concentrations (1,300-2,700 fmol mg-1 protein) of a single low affinity binding site (Kd = 3-5 nM) within these lines. Addition of EGF or TGF-alpha at concentrations greater than 0.1 nM resulted in growth inhibition of all three lines and this was associated with an accumulation of cells in the G2/M phase of the cell cycle. Growth inhibitory effects were not explained by an enhancement of cellular differentiation as monitored by involucrin expression and the ability to form cornified envelopes. While the presence of EGF could not be detected in medium conditioned by the NX002 cell line, mRNA for TGF-alpha was detected in all three lines suggesting the possibility of an autocrine loop. These results together with reports of growth inhibition by EGF and TGF-alpha in other systems suggest that EGF and similar molecules might have a growth regulatory role in lung cancer cells and modulation of such may have therapeutic potential.

Transforming growth factor-beta mRNA expression and growth control of human ovarian carcinoma cells

The pattern of TGF beta expression and in vitro response to TGF beta has been defined in three ovarian carcinoma cell lines (PEO1, PEO4 and PEO14). Marked differences in both mRNA expression and growth responses were detected between the cell lines. All expressed mRNA for TGF beta 3, PEO1 and PEO4 but not PEO14 expressed mRNA for TGF beta 1, whereas PEO14 but not PEO1 and PEO4 expressed TGF beta 2. Growth of PEO14 cells in culture was markedly inhibited by both TGF beta 1 and beta 2. PEO1 cells were inhibited by TGF beta 1, but not TGF beta 2 whilst growth of PEO4 cells were not affected by exposure to either of these peptides. These data indicate that several elements of potential autocrine loops involving TGF beta's are present within ovarian cancer cells.

Mitogenic effects of epidermal growth factor and transforming growth factor-alpha on EGF-receptor positive human ovarian carcinoma cell lines

The role of epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) in the growth modulation of three human ovarian adenocarcinoma cell lines, PEO1, PEO4 and PEO14, has been examined by measuring responses of the cells growing in monolayer culture to exogenous addition of the growth factors. The presence of EGF receptors in the cell lines has been confirmed by ligand binding and immunocytochemical staining using a monoclonal antibody directed against the EGF receptor. The growth of all three cell lines was stimulated by both EGF and TGF-alpha. Dose-response effects were noted with the greatest growth stimulation occurring at concentrations between 0.1 and 10 nmol/l. The stimulatory effects of EGF and TGF-alpha were accompanied by changes in the cell cycle distribution as detected by flow cytometric analysis. It is concluded that EGF and TGF-alpha are important growth regulators in these EGF-receptor positive ovarian cancer cells.

Characterisation and properties of a small cell lung cancer cell line and xenograft WX322 with marked sensitivity to alpha-interferon

Controversy exists as to whether interferons usefully influence the growth of epithelial carcinomas. A small cell lung carcinoma (SCLC) cell line, WX322, has been derived which is greater than 1000-fold more sensitive to alpha-interferon (IFN) when grown in agar than other reported SCLC cell lines. The WX322 line has been characterised to prove its epithelial origin and its chemosensitivity compared with that of the NCI-H69 small cell line. The WX322 cell line expresses neuroendocrine and epithelial markers and possesses a morphology consistent with SCLC origin. A concentration of 5 IU ml-1 of IFN produced 50% inhibition of colony formation in agar in the WX322 line, whereas a concentration of greater than 10(5) IU ml-1 was required to produce a comparable effect with the NCI-H69 cell line. In contrast, WX322, possessed similar sensitivity to NCI-H69 cells when exposed to a range of cytotoxic agents. Analysis of the cell cycle indicated that IFN increased the percentage of cells in the G0/G1 phase for the WX322 cell line but increased the percentage in S phase for the NCI-H69 line. Growth of the xenograft, from which the cell line was derived, was also inhibited by IFN at doses greater than 10(5) IU/mouse/day. The WX322 cell line whether grown in agar or as a xenograft shows an unusually high sensitivity to IFN and provides an interesting model for studying mechanisms of IFN cytotoxicity to epithelial cells.

Modulation of the cluster 1 and mucin antigens in human small cell lung cancer and other epithelial tumour cell lines after treatment with the differentiation inducing agent, sodium butyrate

The expression of the human small cell lung cancer (SCLC) cluster 1 antigen and the human milk fat globule membrane (HMFG) antigen were studied in three SCLC, three lung adenocarcinoma, six ovarian adenocarcinoma and three colorectal adenocarcinoma cell lines before and after culture in the presence of the differentiation inducing agent, sodium butyrate. Before treatment, only SCLC and well differentiated ovarian cell lines expressed the cluster 1 antigen. After 4 days culture with sodium butyrate, expression of cluster 1 antigen was induced in poorly differentiated ovarian, colorectal and lung adenocarcinoma cell lines whereas existing antigen expression was enhanced in SCLC and well differentiated ovarian cell lines. The expression of the HMFG antigen was also modified. Induction of cluster 1 antigen correlated with increased levels of alkaline phosphatase in the treated cell lines, this enzyme being associated with a more differentiated state in colon and ovarian carcinoma cell lines. The pattern of induction of cluster 1 antigen expression suggests that several different epitopes of this antigen are recognised by the ten SCLC cluster 1 antibodies studied.

Oestrogen receptor expression and the effects of oestrogen and tamoxifen on the growth of human ovarian carcinoma cell lines

To assess the role of oestrogen regulation in the growth of ovarian cancer, we examined the effects of an oestrogen, 17 beta-oestradiol, and an anti-oestrogen, tamoxifen, on oestrogen receptor (ER) -positive and -negative human ovarian carcinoma cell lines. As measured by a dextran-coated charcoal adsorption assay, cell lines PEO1, PEO4 and PEO6 possessed moderate concentrations of ER (96-132 fmol mg-1 protein), PEA1 and PEA2 had low values (12-23 fmol mg-1 protein) and PEO14, TO14, PEO23 and PEO16 were ER-negative. Addition of 17 beta-oestradiol (10 nM or 0.1 nM) to the ER +ve cell line, PEO4, increased the growth rate. This oestrogen stimulation could be blocked by 1 microM tamoxifen. In contrast, the growth rate of the ER -ve cell line PEO14 was unaffected by the addition of 17 beta-oestradiol or tamoxifen. Concentrations of tamoxifen in excess of 8 microM were required to produce complete cytostasis in all lines. This concentration of tamoxifen over 72 hours also inhibited 50% colony formation when cells were plated on plastic. These data indicate that some ovarian carcinoma cell lines contain ER and their growth can be sensitive to oestrogen and anti-oestrogen modulation.

Characterization and properties of nine human ovarian adenocarcinoma cell lines

Four series of cell lines have been derived from patients with ovarian adenocarcinoma. Nine cell lines have been established at one from a solid metastasis. Six lines were derived from the ascites or pleural effusion of patients with poorly differentiated adenocarcinoma: PEO1, PEO4, and PEO6 from one patient, PEA1 and PEA2 from a second, and PEO16 from a third. Three lines (PEO14 and PEO23 from ascites and TO14 from a solid metastasis) were derived from a patient with a well-differentiated serous adenocarcinoma. Each set of cell lines was morphologically distinct. The five cell lines PEO1, PEO4, PEO6, PEA1, and PEA2 had cloning efficiencies on plastic of 1-2% and only a few cells in these lines expressed alkaline phosphatase or vimentin. Only a low percentage of these cells reacted with the monoclonal antibodies 123C3 and 123A8 but most reacted with OC125. Conversely the cell lines PEO14, TO14, PEO23, and PEO16 were characterized by low cloning efficiency values (less than 0.05%), marked expression of alkaline phosphatase and vimentin, and good reaction with 123C3 and 123A8 but not OC125. These four cell lines also exhibited dome formation. Four of the cell lines, PEO1, PEO4, PEO6, and PEO16, have been xenografted into immune-deprived mice and found to be tumorigenic.

Effect of sodium butyrate and other differentiation inducers on poorly differentiated human ovarian adenocarcinoma cell lines

We have studied the effects of sodium butyrate, retinoic acid, and dimethyl sulfoxide on two human ovarian carcinoma cell lines PE04 and PE01. PE04 cells, after treatment with sodium butyrate at cytostatic doses (2-3 mM for 4 days), exhibited phenotypic changes including induction of alkaline phosphatase and determinants recognized by the monoclonal antibodies 123C3 and 123A8. These effects are not simply the result of cytostasis as they were not produced by dimethyl sulfoxide or retinoic acid. Other markers are also modified by sodium butyrate including lipid, acid mucin, and glycogen. Retinoic acid modulated expression of lipid and CA125, while dimethyl sulfoxide reduced expression of CA125. Other short chain fatty acids such as propionic acid and valeric acid (in addition to butyric acid) also induced alkaline phosphatase and the determinants recognized by 123C3 and 123A8 in PE04 cells. Other differentiation inducers and cytotoxic agents studied did not induce these markers at cytostatic concentrations. The effects of sodium butyrate (and related short chain fatty acids) thus appear to be relatively specific for this cell line.

Investigations of the relationship between cell proliferation and differentiation of HL-60 cells induced to differentiate by N-methylformamide

The relationship between the N-methylformamide (NMF)-induced differentiation of HL-60 human promyelocytic leukemia cells, to myeloid cells, and their proliferative potential was determined in suspension culture. Continuous incubation with 170 mM NMF induced 70% of cells to differentiate after 2-2.5 cell divisions, whether or not cells were replenished with fresh medium and serum. 100 mM NMF induced significant levels of differentiation only when cells were allowed to reach a plateau of growth, and this was prevented by replenishment of the medium and serum. Under these conditions of "re-feeding", the cells could be made to undergo greater than 10 cell divisions, and differentiated only when they were allowed to reach a plateau in their growth. The data suggests that NMF may induce differentiation only when the proliferative potential of the cells is limited, either by the drug itself or by the conditions of growth.

Antitumor activity and pharmacokinetics in mice of 8-carbamoyl-3-methyl-imidazo[5,1-d]-1,2,3,5-tetrazin-4(3H)-one (CCRG 81045; M & B 39831), a novel drug with potential as an alternative to dacarbazine

A number of 3-alkyl analogues of the experimental antitumor drug mitozolomide [8-carbamoyl-3-(2-chloroethyl)imidazo[5,1-d]-1,2,3,5-tetrazin-4(3H )-one] have been screened against murine tumors in vivo. Only the compounds with a 3-methyl- or 3-bromoethyl group possessed significant antitumor activity against the TLX5 lymphoma. The 3-methyl analogue, 8-carbamoyl-3-methylimidazo[5,1-d]-1,2,3,5-tetrazin-4(3H)-one (CCRG 81045), was investigated further and found to possess good activity, when administered i.p., against the L1210 and P388 leukemias, the M5076 reticulum cell sarcoma, B16 melanoma, and ADJ/PC6A plasmacytoma. The drug was also active when administered p.o. to mice bearing the L1210 leukemia. A daily for 5 days schedule of 100 mg/kg CCRG 81045 produced increases of survival time of treated animals compared to controls of 176 and greater than 235% against the P388 and L1210 leukemias, respectively. In the female C57BL x DBA/2 F1 mouse the 10% lethal dose was 125 mg/kg daily for 5 days. CCRG 81045 was found to undergo mild alkaline hydrolysis and ring fission to form the linear triazene 5-(3-methyltriazen-1-yl)imidazole-4-carboxamide, which is the putative metabolite formed upon metabolic activation of the antitumor drug dacarbazine [5-(3,3-dimethyltriazen-1-yl)imidazole-4-carboxamide]. The half-life of CCRG 81045 at 37 degrees C in 0.2 M phosphate buffer (pH 7.4) was 1.24 h, whereas that of 5-(3-methyltriazen-1-yl)imidazole-4-carboxamide at 25 degrees C was reported to be 8 min (F. H. Shealy and C. A. Krauth, J. Med. Chem., 9:34-37, 1966). The half-life of CCRG 81045 in human plasma in vitro at 37 degrees C was 0.42 h. Pharmacokinetic experiments conducted in BALB/c mice produced plasma profiles of CCRG 81045, administered i.p. or p.o., which showed a rapid absorption phase, elimination half-lives of 1.13 h (i.p.) and 1.29 h (p.o.), and a bioavailability of 0.98.