In vitro transformation of human congenital naevus to malignant melanoma.

The incidence of melanoma is estimated to be growing at the second fastest rate among all cancers in the United States. The progression of the melanocyte to a malignant melanoma involves various sequential steps: development of benign naevocellular naevus, preneoplastic dysplastic naevus, primary melanoma, and metastatic melanoma. Despite these clearly defined stages, very little is known about the molecular events leading to melanoma progression. We established a human congenital naevus cell line (UISO-CMN-1). UISO-CMN-1 cells were confirmed to have melanocytic origin by S100 immunoreactivity and the presence of melanin granules and melanosomes. UISO-CMN-1 cells, even though they showed structural and numerical abnormalities in karyotype, were non-tumorigenic when transplanted into athymic mice. However, following frequent exposure to ultraviolet C radiation, UISO-CMN-1 cells acquired tumorigenic potential. Transformation of UISO-CMN-1 cells into tumorigenic cells was accompanied by induction of ganglioside-2 expression without any significant changes in cellular ganglioside-3. These transformed and non-transformed UISO-CMN-1 cell lines can serve as excellent research tools for studying the molecular changes associated with melanoma development and progression, and for identifying agents that might prevent development of malignant melanoma.

Differentiation of human breast carcinoma cells by a novel vitamin D analog: 1alpha-hydroxyvitamin D5.

The active metabolite of vitamin D, 1alpha,25-dihydroxyvitamin D3, can induce differentiation in breast cancer cells; however, it is hypercalcemic in vivo. Therefore, development of non-calcemic analogs of vitamin D has received considerable attention. Recently, we synthesized an analog of vitamin D [1alpha(OH)D5] that exhibits much less calcemic activity than 1alpha,25-dihydroxyvitamin D3. In this study, we evaluated the cell-differentiating action of 1alpha(OH)D5 in breast cancer cells. Following 10 days treatment with 1alpha(OH)D5 [(10-7 M) in UISO-BCA-4], we observed induction of intracytoplasmic casein, intracytoplasmic lipid droplets, ICAM-1, nm23, and specific biomarkers associated with breast cell differentiation. 1alpha(OH)D5 treatment also showed induction of vitamin D receptor and TGFbeta1 proteins. UISO-BCA-4 cells pretreated for 10 days in vitro with 1 microM 1alpha(OH)D5 failed to form tumors when transplanted into athymic mice. Similarly, 4 and 8 ng 1alpha(OH)D5 treatment three times weekly inhibited the growth of UISO-BCA-4 cells injected into athymic mice. These results suggest that this new vitamin D analog may be of significant therapeutic value for breast cancer.

Metabolism of N-[4-hydroxyphenyl]retinamide (4-HPR) to N-[4-methoxyphenyl]retinamide (4-MPR) may serve as a biomarker for its efficacy against human breast cancer and melanoma cells.

A clinical trial of N-[4-hydroxyphenyl]retinamide (4-HPR) has been in progress for the past 4 years to evaluate its role in chemoprevention of breast cancer. However, it is currently not known whether the effect of 4-HPR in breast cells is mediated by 4-HPR directly or through one of its metabolites. In this report, we investigated in vivo and in vitro effects of 4-HPR on three different breast carcinoma cells and two different melanoma cell lines. In vitro, the growth of all three breast carcinoma cell lines was inhibited by 4-HPR. Only one of two melanoma cell lines (UISO-Mel-1) showed growth inhibition to 4-HPR. The cell lines sensitive to 4-HPR in vitro also showed inhibition to 4-HPR in a xenograft model. Dietary 4-HPR (0.5 mmol/kg diet) reduced the growth of UISO-BCA-1 xenografts in female athymic mice, but had no effect on UISO-Mel-6 xenografts. Metabolism investigations of the 4-HPR-sensitive and insensitive cell lines indicated that N-[4-methoxyphenyl]retinamide (4-MPR), the major metabolite of 4-HPR, was detected only in cells sensitive to 4-HPR. Further in vitro studies with 4-MPR suggested that it is not an active metabolite of 4-HPR as it failed to inhibit growth of 4-HPR-resistant UISO-Mel-6 cells, and showed no dose-dependent inhibition of 4-HPR-sensitive breast carcinoma and melanoma cell lines. Our results in the present study indicate that, although 4-MPR is not an active metabolite of 4-HPR, detection of this metabolite in the malignant cells may serve as an indirect biomarker to predict response of cells to 4-HPR.

Development of a new metastatic human breast carcinoma xenograft line.

Xenografts originated from human tumours offer the most appropriate research material for in vivo experimental research. However, primary human breast carcinomas are difficult to grow when transplanted in athymic mice: tumour take is less than 15%. Recently, we have achieved 60% tumour take by injecting tumour cell suspensions mixed with Matrigel. Human breast xenografts originated from primary breast carcinoma also frequently show the potential to metastasize spontaneously. In the present study, we generated a human breast carcinoma xenograft line (UISO-BCA-NMT-18) that shows 100% tumorigenicity and 80-100% lung metastasis when transplanted s.c. in athymic mice. We have studied in detail the characteristics of the xenograft and the patient's tumour from which the xenograft line originated. Both the xenograft and the patient's tumour showed intense staining for mutant p53 nuclear protein, and high expression of U-PA, PAI and u-PAR. In vivo growth of the xenograft is stimulated by exogenous supplementation of oestrogen. This xenograft is continuously growing in mice and has shown 80-100% metastasis for the last three successive in vivo passages. This well-characterized, oestrogen-responsive, metastatic breast carcinoma xenograft line will provide excellent research material for metastasis-related research.

Conservation genetics of the koala (Phascolarctos cinereus): low mitochondrial DNA variation amongst southern Australian populations.

Koala (Phascolarctos cinereus) populations in southern Australia have a history of bottlenecks-earlier this century the species became extinct in South Australia, and almost so in Victoria. Subsequently large numbers of animals from island populations (founded from very few animals) have been translocated back to mainland sites and to other islands in the region. As part of a larger study of the genetic structure of koala populations in southern Australia, we have undertaken a survey of mitochondrial DNA restriction fragment length polymorphism (mtDNA-RFLP) variability. Genomic DNA from 91 koalas from five populations was examined using 23 restriction enzymes, and mtDNA fragments were detected using a domestic cat full-length mtDNA clone. Only one of the enzymes, TaqI, revealed polymorphism-a relatively low amount of variation compared with other mammals, although low mtDNA-RFLP variation has also been reported in Queensland koalas. French Island and populations established predominantly from French Island immigrant koalas, either directly or via other island populations, were indistinguishable by haplotype frequencies. The mtDNA data are thus consistent with the interpretation that the koala translocation programme has homogenized gene frequencies amongst those populations involved. South Gippsland is not recorded as having received translocated koalas directly, and has significantly different mtDNA-RFLP haplotype frequencies from all other populations examined. The fact that this distinction was not previously observed in nuclear gene frequencies may reflect predominantly male-mediated dispersal in koalas.

Evaluation of the mutagenic, cytotoxic, and antitumor potential of triptolide, a highly oxygenated diterpene isolated from Tripterygium wilfordii.

Triptolide, a highly oxygenated diterpene isolated from Tripterygium wilfordii Hook f. (Celastraceae), has been shown to demonstrate potent antileukemic activity in rodent models at remarkably low treatment doses. A variety of other physiological responses are known to be mediated by this compound, including immunosuppressive and antifertility effects. We currently report that triptolide was not mutagenic toward Salmonella typhimurium strain TM677, either in the presence or absence of a metabolic activating system. Relatively potent but non-specific cytotoxicity was observed with a panel of cultured mammalian cell lines, and modest antitumor activity was observed when an i.p. dose of 25 microg was administered three times weekly to athymic mice carrying human breast tumors. Treatment regimens involving higher doses of triptolide (e.g. 50 microg/mouse three times weekly) were lethal.

Overexpression of mutant p53 and c-erbB-2 proteins and breast tumour take in mice.

We established a panel of 17 xenografts from primary human breast carcinomas. We examined which characteristics of the original tumours and the xenografts facilitate growth in animals. Tumours expressing medium or strong immunoreactivity for p53 protein had significantly (P < 0.05) higher incidence (92%) of in vivo tumour take than those showing weak or negative immunoreactivity (9.1%). No such association was observed between either c-erbB-2 or epidermal growth factor receptor (EGFR) expression in the original tumours and their in vivo tumour take. Following subcutaneous (s.c.) transplantation of original breast tumours or established xenografts, 7/17 tumours showed metastatic disease spread to distant sites (mainly lungs). This study suggests that selective growth of highly aggressive tumours occurs during in vivo propagation of malignant tumours, and these tumours will be of particular interest in evaluating various chemotherapeutic agents for breast cancer management.

A cell line derived from a clinically benign phyllodes tumor: characterization and implications.

Phyllodes are uncommon tumors of the breast. Improved understanding of their behavior is hampered by the paucity of good laboratory models. We have developed two cell lines, by both xenograft and direct cell culture, derived from a histologically benign phyllodes tumor. Both cell lines have the same characteristics and growth kinetics. They grow as monolayers of spindle-shaped cells, with surface markers consistent with a mesenchymal origin. They do not express either estrogen or progesterone receptors. The cells have a relatively short doubling time of just over 1.5 days, and show a stimulatory effect with the addition of insulin. Karyotype analysis reveals the absence of one X chromosome.

Growth and metastasis of human breast carcinomas with Matrigel in athymic mice.

Immunodeficient athymic mice with human tumor xenografts provide an important in vivo experimental model for cancer research. However, only a limited number of tumor types grow in these animals. For human breast carcinomas, the incidence of tumor-take is 6-15%. Recently, increased incidence of xenograft development in mice has been reported for various human tumors when the tumors were coinjected with Matrigel. We studied the development of human breast carcinoma xenografts in athymic mice with and without coinjection of Matrigel. Tumors developed in only 7.3% of enzyme-dispersed tumors injected subcutaneously in saline solution alone. None of these tumors metastasized to distant sites. On the other hand, 50% of enzyme-dispersed tumors coinjected with Matrigel developed xenografts; four out of five of these tumors metastasized to distant sites. Our data from the recent study suggest that, in athymic mice, Matrigel not only enhanced breast tumor growth but also facilitated tumor metastasis.

Human breast carcinoma cell lines: ultrastructural, genotypic, and immunocytochemical characterization.

Two new breast carcinoma cell lines, designated as UISO-BCA-1 and UISO-BCA-2, have been established from pleural effusions of postmenopausal women. Both cell lines show properties of mammary epithelial cells, such as positive immunoreactivity to cytokeratins and human milk fat globulin, presence of desmosomal junctions, numerous microvilli, intracytoplasmic duct-like vacuoles and tonofilaments. UISO-BCA-1 and UISO-BCA-2 cells differ from each other with respect to cellular morphology, ultramicroscopic details, immunoreactivity to Her-neu oncogene protein, chromosomal mode and in vivo and in vitro growth rates. UISO-BCA-1 cells are well-differentiated (as evident from their morphology and ultrastructural details) and hyperploid (42-114 chromosomes). In vitro, UISO-BCA-1 cells are fast growing, with a population doubling time of 31.2 +/- 9.6 hrs (n = 4), and are tumorigenic (100%) in athymic nude mice. In contrast, UISO-BCA-2 cells are poorly differentiated, but are also hyperploid, with 54-64 chromosomes. UISO-BCA-2 cells are slow growing in vitro (population doubling time: 56.0 +/- 5.0 hrs [n = 4]) and have limited tumorigenic potency (20-40%). Both these cell lines are estrogen and progesterone receptor (less than 10 fmol/mg protein) negative.

Breast tumor-derived factors stimulate reduction of estrone to estradiol in nonmalignant breast tissue.

This study examines the paracrine influence by human breast carcinoma cells (UISO-BCA-1) on nonmalignant breast tissue in vitro. The 17 beta-OH-SDH-mediated reductive pathway (estrone-->estradiol) was significantly increased in nonmalignant breast tissue coincubated with human breast carcinoma cells, compared to control tissues incubated in the media alone. No influence on the enzyme activity was noticed in coincubated breast cancer cells. Preincubation of breast cancer cells with estradiol (10(-8) M) significantly decreased the enzyme activity in coincubated nonmalignant breast tissue, which was restored to control levels by addition of R5020 (10(-8) M), tamoxifen (10(-6) M), or a combination of both. In nonmalignant tissues incubated in the presence of growth factor TGF alpha, enzyme activity was reduced to between 46% and 76%. No other growth factors (IGF I, IGF II, PDGF) influenced enzyme activity. In nonmalignant tissues incubated with malignant tumor cytosol, enzyme activity was increased in 16% cases, inhibited in 21%, and not significantly changed in 63%. The data from the present study suggest that factors produced by breast carcinoma cells may influence interconversion of estradiol in nonmalignant tissue. In patients, factors produced by malignant tumor mass may have paracrine influence on surrounding nonmalignant breast tissue and, thereby, may influence the estrogen availability to tumor mass.

The interaction of the potential-sensitive molecular probe merocyanine 540 with phosphorylating beef heart submitochondrial particles under equilibrium and time-resolved conditions.

The interaction of the potential-sensitive extrinsic molecular probe merocyanine 540 ( M540 ) with phosphorylating submitochondrial particles has been investigated under equilibrium and time-resolved conditions. The addition of ATP to a M540 -membrane suspension produces oligomycin and CCCP-sensitive spectral changes with absolute maxima near 490, 530, and 565 nm; a 1- to 2-nm red shift of the dye absorption spectrum is also evident in the longer-wavelength region of the spectrum. In fixed-wavelength work, the energy-dependent optical signals were increased by the addition of nigericin and NH4Cl, and could be subsequently restored to the control level by valinomycin or KSCN, respectively. These observations suggest that M540 is specifically sensitive to the membrane-potential portion of the electrochemical gradient presumably present in the submitochondrial particle system in the presence of substrate. Binding analyses based on the Langmuir adsorption isotherm and the direct linear method indicate that the M540 dissociation constant is decreased by the presence of ATP with little or no change in the maximum number of binding sites. The M540 dissociation constant was markedly decreased when 0.1 M NaCl was present in the medium, suggesting that the association of this probe with the membrane may be subject to considerable surface charge repulsion. Results from the binding analyses indicate that the origin of the energy-dependent spectral changes may be an enhanced association of M540 with the submitochondrial particle membrane resulting from the transfer of dye from the aqueous phase to membrane-binding sites. The time course of the NADH-, ATP-, or succinate-induced signal developed slowly, on a time scale of tens of seconds, and follows a second-order rate law, suggesting that the rate-limiting step in the development of the ATP-induced M540 signal may be the transfer of dye from the aqueous phase to membrane-binding sites. The enhanced passive binding of M540 to the submitochondrial particle membrane in the presence of NaCl reduces the concentration of free dye apparently available to redistribute to the membrane when substrate is present, with a concomitant reduction in the observed pseudo-first-order and the second-order rate constants. If the effective free dye concentration is estimated from binding data and used in the plot from which the latter rate constant is obtained, the value of this constant compares favorably with the obtained in the absence of the electrolyte.(ABSTRACT TRUNCATED AT 400 WORDS)

Evidence for a defective mitochondrial membrane in 1,2-dimethylhydrazine-induced colon adenocarcinoma in rat: enhanced lipid peroxidation potential in vitro.

Enhanced lipid peroxidation potential was measured in Holtzman rat colon tumors induced by chronic subcutaneous injection of 1,2-dimethyl-hydrazine as compared with normal colonic tissue. The peroxidation potentials were determined in the mitochondrial cellular components by measuring the ferrous-ascorbate induced formation of malondialdehyde. The tumor mitochondria were found to peroxidize at a rate 8-10-fold higher than the comparable normal tissue components. In addition, we found that the mitochondria from the cancer cells exhibited reduced NADH-cytochrome c reductase activity. These observations suggest an involvement of non-enzymatic free radical flux in DMH-induced carcinogenesis, which may be the result of structurally altered mitochondrial membranes.

Cyclic nucleotide concentrations in 7.12-dimethylbenz[a]anthracene-induced pancreatic cancer in rats.

Pancreas cancer was induced in noninbred male Holtzman rats by the implantation of beeswax containing 7.12-dimethylbenz[a]anthracene (DMBA) into the "head" of the pancreas. The tumors that developed 4--6 months later were examined for their cyclic AMP and cyclic GMP levels. The lesions could be considered in one of two categories according to their cyclic nucleotide contents: lesions with significantly smaller amounts and those with greater amounts, compared with levels measured in the pancreas tissues of the control rats. The existence of two biochemically distinct groups may indicate different growth patterns of the DMBA-induced pancreatic neoplasia.

The effect of oral glucose on von Willebrand factor activity in normal and diabetic subjects.

We have previously noted increased platelet aggregation and high von Willebrand factor activity in patients with chemical diabetes. In this paper we have studied platelet aggregation, plasma glucose, insulin, free fatty acids, growth hormone, and von Willebrand factor activity during the glucose tolerance test in six normal and six chemical diabetic subjects. The results suggest that von Willebrand factor activity is suppressed coincident with the rise of glucose and insulin and provide further evidence of hormonal and metabolic control of levels of von Willebrand factor activity.