A mouse B16 melanoma mutant deficient in glycolipids.

Mouse B16 melanoma cell line, GM-95 (formerly designated as MEC-4), deficient in sialyllactosylceramide was examined for its primary defect. Glycolipids from the mutant cells were analyzed by high-performance TLC. No glycolipid was detected in GM-95 cells, even when total lipid from 10(7) cells was analyzed. In contrast, the content of ceramide, a precursor lipid molecule of glycolipids, was normal. Thus, the deficiency of glycolipids was attributed to the first glucosylation step of ceramide. The ceramide glucosyltransferase (EC 2.4.1.80) activity was not detected in GM-95 cells. There was no significant difference of sialyllactosylceramide synthase activity, however, between GM-95 and the parental cells. The deficiency of glycolipids in GM-95 cells was associated with changes of the cellular morphology and growth rate. The parental cells showed irregular shapes and tended to overlap each other. On the other hand, GM-95 cells exhibited an elongated fibroblastic morphology and parallel arrangement. The population-doubling times of GM-95 and the parental cells in serum-free medium were 28 hr and 19 hr, respectively.     

Interactions among clonal subpopulations affect stability of the metastatic phenotype in polyclonal populations of B16 melanoma cells.

Analysis of the metastatic properties of clones isolated from mouse B16 melanoma cell lines (B16-F1 and F10) shows extensive cellular heterogeneity and the presence of subpopulations that have widely differing metastatic abilities. This pattern of metastatic heterogeneity is maintained during serial passage in vitro and in vivo. In contrast, even a short serial passage of individual clones isolated from these heterogeneous parent lines results in rapid emergence of variant subclones that have different metastatic properties. If several clones are mixed and cocultivated, this instability is not expressed. These data suggest that, in polyclonal populations, the various clonal subpopulations somehow interact with one another to "stabilize" their relative proportions within the population. Restriction of clonal diversity by selective killing of the majority of clones in a polyclonal population eliminates the stabilizing restraints and stimulates rapid emergence of new subpopulations to create heterogeneous populations containing a new panel of phenotypically diverse subpopulations that then reach stable proportions until the next selection pressure(s) is encountered.     

Monoclonal antibodies inhibit the adhesion of mouse B 16 melanoma cells in vitro and block lung metastasis in vivo.

Seven monoclonal antibodies against mouse B 16 melanoma cells (produced in syngeneic C57BL/6 mice) were selected that blocked the adhesion of melanoma cells to tissue culture dishes. These antibodies were found to be directed against antigens on the surface of mouse B 16 melanoma cells but not on normal mouse cells such as 3T3 fibroblasts. Similarly, the antigens could not be detected in normal mouse tissues (e.g., lung, kidney, liver) but were found in lungs colonized by B 16 melanoma cells. Significantly, three of these antibodies virtually abolished lung colonization of highly invasive B 16 sublines injected into the animals' bloodstream. They exerted their effect both when preabsorbed by the melanoma cell in vitro and when delivered to the animals prior to the tumor cells. It is suggested that monoclonal antibodies might be a promising tool for preventing metastasis.     

Influence of L-tyrosine phenol-lyase on the growth and metabolism of B16 melanoma.

Administration of L-tyrosine phenol-lyase inhibited growth of established B16 melanomas in BDF1 mice. Under the conditions used, the enzyme exerted a cytostatic effect on the tumors. The addition of L-tyrosine phenol-lyase to growing melanoma cultures blocked cell division and caused an accumulation of cells in the G1 (G0) pultures was suppressed, the most pronounced effect of L-tyrosine phenol-lyase was a rapid and near-complete cessation of uridine uptake and incorporation. This block in RNA synthesis was also observed in human fibroblasts treated with L-tyrosine phenol-lyase.     

Suppression of lung metastasis of B16 mouse melanoma by N-acetylglucosaminyltransferase III gene transfection.

The beta 1-6 structure of N-linked oligosaccharides, formed by beta-1,6-N-acetylglucosaminyltransferase (GnT-V), is associated with metastatic potential. We established a highly metastatic subclone, B16-hm, from low metastatic B16-F1 murine melanoma cells. The gene encoding beta-1,4-N-acetylglucosaminyltransferase (GnT-III) was introduced into the B16-hm cells, and three clones that stably expressed high GnT-III activity were obtained. In these transfectants, the affinity to leukoagglutinating phytohemagglutinin was reduced, whereas the binding to erythroagglutinating phytohemagglutinin was increased, indicating that the level of beta 1-6 structure was decreased due to competition for substrate between intrinsic GnT-V and ectopically expressed GnT-III. Lung metastasis after intravenous injection of the transfectants into syngeneic and nude mice was significantly suppressed, suggesting that the decrease in beta 1-6 structure suppressed metastasis via a mechanism independent of the murine system. These transfectants also displayed decreased invasiveness into Matrigel and inhibited cell attachment to collagen and laminin. Cell growth was not affected. Our results demonstrate a causative role for beta 1-6 branches in invasion and cell attachment in the extravasation stage of metastasis.     

Influence of collagen substrata on glycosaminoglycan production by B16 melanoma cells.

A cloned metastatic murine melanoma cell line exhibited similar growth characteristics when propagated on either type I collagen, type IV collagen, or plastic. However, cells grown on both types of collagen exhibited an altered cellular morphology and on type IV collagen only, an increased substrate adhesiveness, relative to those maintained on a plastic substratum. Incorporation of [3H]glucosamine and [35S]sulfate into glycosaminoglycans (GAGs) of cells grown on collagen substrates was 20% and 40% less, respectively, than cells grown on plastic, whereas degradation of cell-associated [35S]sulfate-labeled GAGs was similar in cells grown on collagen or plastic. Although the composition of GAGs was similar in all cultures, consisting of approximately 60% chondroitin and 40% heparin or heparan sulfate, the degree of sulfation of the heparin or heparan sulfate molecules was markedly decreased in cultures grown on collagen. The results indicate that the composition of the extracellular matrix influences the biological behavior of B16 melanoma cells, in part by altering the amount and nature of the GAG molecules produced.     

Intraarterial chemotherapy of malignant melanoma metastatic to the liver

BACKGROUND/AIMS: The prognosis of malignant melanoma metastatic to the liver is poor. The aim of the present report was to analyze retrospectively the effectiveness of regional chemotherapy and biologic therapy in patients with hepatic metastases of malignant melanoma. METHODOLOGY: Seven patients with hepatic metastases of malignant melanoma were treated by intraarterial administration of the combination of cisplatin, vinblastine and dacarbazine, or melphalan, with or without interleukin-2, interferon-alpha and interferon-gamma. RESULTS: The median survival of 4 patients with metastatic involvement initially limited to the liver is 19+ months in contrast to a median survival of 5 months in patients with concurrent extrahepatic disease. Intraarterial administration of cytokines led to an initial decrease in circulating lymphocyte numbers, with subsequent return to pretreatment levels, and to an increase in urinary neopterin, a marker of immune activation. CONCLUSIONS: Regional intraarterial administration of chemotherapy with or without cytokines may be effective for controlling hepatic metastases of malignant melanoma in patients with disease limited to the liver, but little benefit is evident in patients who present with concurrent extrahepatic disease.     

Novobiocin modulates colchicine sensitivity in parental and multidrug-resistant B16 melanoma cells

The effect of the antibiotic agent novobiocin on the sensitivity of melanoma cells to colchicine and vinblastine was examined in drug-sensitive and drug-resistant B16 melanoma cells. A cell line COL/R was selected for colchicine resistance. The COL/R cell line (resistant to 80 ng/ml colchicine) was found to possess the multidrug-resistant (MDR) phenotype. The cells were shown to be cross-resistant to vinblastine and Adriamycin and to overexpress P glycoprotein. P glycoprotein activity was assessed by using the rhodamine 123 accumulation test. Rhodamine accumulation was markedly decreased in COL/R cells as compared to the parental B16 cells. Verapamil reversed drug resistance and increased rhodamine accumulation in COL/R cells. Novobiocin in combination with colchicine or vinblastine synergistically inhibited the proliferation of parental B16 cells. In COL/R cells, novobiocin markedly decreased colchicine resistance and increased rhodamine accumulation. These data show that novobiocin incrases the sensitivity of both parental and MDR melanoma cells to microtubule-disrupting cytotoxic drugs.Abbreviation PGP P glycoprotein     

Influence of retinoids on growth and melanin content of Harding-Passey-melanoma cells in vitro and B16 transplantable melanoma in vivo

Growth cessation and cell death of exponentially proliferating Harding-Passey melanoma cells (HPM-73 line) in monolayer culture resulted in the presence of 3.3 X 10(-5) M retinal, while retinol and retinoic acid caused growth retardation at 3.3 X 10(-5) M. Also at 1 X 10(-5) M, the growth-inhibitory effect of retinal was more pronounced than that of retinol or retinoic acid. Following serum removal from the culture media, all 3 retinoids at 3.3 X 10(-6) M or 1 X 10(-5) M revealed cytotoxic effects within 3 days as demonstrated by cell loss from the substratum. Thus, the presence of serum has "protective" effects. Addition of retinal, retinoic acid or retinol at 1 X 10(-5) M to cultures in stationary growth phase did not result in cell loss during period of 6 days. C57Bl mice with B16 melanotic melanoma were i.p. injected during 10 days with retinoids (30 or 100 mcg per mouse daily). All retinoids inhibited B16 tumor growth in vivo. In this respect, retinoic acid was the most effective one. The cellular melanin content of cultured HPM-cells and of B16 melanotic melanoma in vivo was elevated after treatment with retinoids; retinal having the strongest effect.     

Role of Kupffer cells in arresting circulating tumor cells and controlling metastatic growth in the liver

Metastasis to the liver is a common event in clinical oncology. Blood-borne tumor cells (TCs) arriving to the liver sinusoids run into a special vascular bed. The lining of liver sinusoids is shared by Kupffer cells (KCs) and endothelial cells. KCs, liver-fixed macrophages, are responsible for detection and removal of "non-self" particles. To investigate their role in arresting blood-borne TCs and controlling tumor growth, we injected a syngeneic colon carcinoma cell line into a mesenteric vein of two groups of rats; one group was without Kupffer cells and the other normal controls. We removed the liver of these animals at different time intervals and performed immunohistochemical analysis with monoclonal antibodies (MoAbs) against our tumor cell line, three macrophage subpopulations, natural killer cells, and B and T lymphocytes. Additionally, we showed in vitro spontaneous cytotoxicity of KCs against our tumor cell line. Results suggest that KCs play a relevant role in arresting circulating TCs at the liver sinusoid, although it is limited to a small number of malignant cells. They also seem to play a major role in clearing neoplastic cells from the liver parenchyma, in controlling tumor growth in the very early stages of metastatic development, and in modulating the host immune response to cancer cells. (Hepatology 1996 May;23(5):1224-31)     

Adult-to-adult living donor liver transplantation for malignant metastatic melanoma to the liver

BACKGROUND:Metastases from malignant melanoma to the liver are rare in China,and surgical resection may be of potential benefit.Liver transplantation for this disease has never been reported.METHODS:We report a case of adult-to-adult living donor liver transplantation(A-A LDLT)for metastatic melanoma.With a surgical history of ocular melanoma,the recipient presented with emaciation from a large right hepatic mass which also probably had portal vein invasion.A-A LDLT was successfully performed and no postoperative complications were observed in either the donor or the recipient.Postoperative pathology confirmed the diagnosis of metastatic malignant melanoma;however no adjuvant chemotherapy was employed after transplantation.We also reviewed the literature on the surgical treatment of metastatic malignant melanoma to the liver and discussed the LDLT indications.RESULT:Recurrence occurred 6 months after surgery and the patient died from recurrence of the disease 8 months posttransplant.CONCLUSIONS:Review of the literature suggested that only a small subset of selected patients may benefit from liver resection.Large metastatic disease in the liver potentially involving a major vessel,as in this case,should be contraindicated for liver transplantation.     

Benzodiazepines have high-affinity binding sites and induce melanogenesis in B16/C3 melanoma cells.

We found that two markers of differentiation, tyrosinase (monophenol, dihydroxyphenylalanine:oxygen oxidoreductase, EC 1.14.18.1) activity and melanin synthesis, are induced by diazepam in B16/C3 mouse melanoma cells. We also demonstrated high-affinity binding sites for [3H]diazepam in these cells by radioreceptor assay, and we visualized binding to the cell surface by fluorescence microscopy with a benzodiazepine analog conjugated to a fluorescein-labeled protein. Our studies also showed that there are differences between the binding characteristics in intact cells and in membrane fractions prepared from these cells. Scatchard analysis of the binding data from membrane fractions gave a linear plot (Kd = 9.1 X 10(-8) M). With intact cells, a curvilinear Scatchard plot was obtained. This was resolved into two components defining binding sites with affinity constants of 1.7 X 10(-9) M and 4.6 X 10(-7) M. Thus, it appears that [3H]diazepam binding in intact cells is more complex than in isolated membranes. Several related benzodiazepines, including flunitrazepam, Ro-5-4864, nitrazepam, oxazepam, lorazepam, Ro-5-3072, chlordiazepoxide, and clonazepam also induced melanogenesis. When these compounds were tested for their ability to inhibit [3H]diazepam binding, flunitrazepam, diazepam, and Ro-5-4864 were found to be the most effective inhibitors. These three compounds were also the most potent in inducing melanogenesis. Our results suggest that the benzodiazepines modulate cell differentiation. The presence of high-affinity binding sites in this homogeneous, easily grown cell line may provide a useful model for studies on the mechanism of action of these compounds.     

Intrasinusoidal metastatic melanoma of the liver with reactive hepatitis. An immunologic phenomenon?

The macrophage migration inhibition factor (MIF) test toward extracts of choroidal melanoma was repeated four times in a patient with ocular malignant melanoma. In the initial stage, when there was only an ocular finding, the MIF test result was positive. It remained so for a period of two years, even when intrasinusoidal hepatic diffusion developed concomitantly with a nonspecific reactive hepatitis. These histologic findings can be interpreted as evidence of the presence of an immune reaction at a particular moment in the disease process. Several months later, when the patient's condition went into an abrupt decline and showed extensive nodular spread, the results of MIF test were found to have become negative.     

Hepatocyte growth factor overexpression ameliorates liver inflammation and fibrosis in a mouse model of nonalcoholic steatohepatitis

Background  

Hepatocyte growth factor (HGF) is a potent growth factor involved in liver regeneration that has various effects on epithelial and nonepithelial cells. Although it has been demonstrated that HGF can reduce liver inflammation or fibrosis caused by pharmaceutical or chemical insult, no examination of its effect on liver injury in nonalcoholic steatohepatitis (NASH) has been reported.     

弓形虫感染小鼠血清对小鼠B16黑色素瘤细胞增殖和凋亡的影响

目的观察RH株弓形虫感染小鼠血清在体外对小鼠B16黑色素瘤细胞增殖以及凋亡的影响。方法B16细胞在含5%、10%和20%RH株弓形虫感染小鼠血清RPM1640中培养24和48 h,四甲基氮噻唑蓝（MTT）法检测B16细胞增殖抑制率;在10%、20%感染小鼠血清中培养24 h,Annexin V/PI染色,流式细胞检测细胞凋亡,HE染色观察细胞形态改变。结果正常血清能促进B16细胞增殖。5%、10%和20%弓形虫感染小鼠血清与B16细胞共孵育24和48 h,细胞生长抑制率分别为（9.06±0.36）%（、14.77±0.94）%（、23.74±0.5）%和（14.82±0.77）%（、24.56±1.04）%、（39.77±2.82）%,与对照组比较差异有统计学意义（P〈0.05）;10%、20%弓形虫感染鼠血清组B16细胞24 h凋亡率分别为（26.01±3.27）%和（44.55±2.87）%,显著高于对照组凋亡率（5.01±2.62）（P〈0.05）。弓形虫感染鼠血清作用的B16细胞生长密度明显降低,细胞核固缩、浓染。结论RH株弓形虫感染血清能够抑制B16细胞增殖并促进其凋亡。     

Anorectal melanoma metastatic to the breast.

Anorectal melanoma is an extremely rare malignancy with poor prognosis. Patients generally present with a sensation of mass and rectal bleeding, which is usually attributed to hemorrhoids or polyps. It can not be diagnosed early because of these benign symptoms, so it is bulky at the time of presentation. Despite aggressive surgery, 5-year survival is less than 10%. We present a case of inoperable anorectal melanoma which metastasized to the left breast and abdominal lymph nodes. We also briefly reviewed the appropriate literature, emphasizing the diagnostic and therapeutic approaches.     

Ectopic Agouti protein overexpression increases stimulated corticosterone production without effect on adenylate cyclase activity in mouse adrenal cells

OBJECTIVE: The antagonism of Agouti protein (AP) and Agouti-related protein on melanocortin receptors suggests an inhibitory role in the regulation of steroidogenesis. However, we have previously demonstrated that ectopic AP overexpression increased restraint-induced corticosterone release and adrenal reactivity to ACTH in mice. A high steroidogenic response to ACTH may be a consequence of a stimulatory AP action on the adenylate cyclase (AC) and/or intracellular steroidogenic enzymes. The aim of the present study was to estimate the effect of ectopic AP overexpression on the activity of AC and steroidogenic intracellular enzymes. METHODS: ACTH and forskolin were used for AC stimulation, and dibutyryl cAMP and progesterone were used for stimulation of intracellular steroidogenic enzymes in isolated adrenal cells in male C57Bl/6J mice of two Agouti genotypes: A(y)/a (ectopic AP overexpression) and a/a (absence of AP in all tissues). RESULTS: ACTH and forskolin increased cAMP accumulation to the same extent in both A(y)/a and a/a mouse adrenal cells (P<0.001; ANOVA), but resulted in higher corticosterone production in A(y)/a mice (P<0.001 for ACTH and P<0.01 for forskolin; ANOVA). Dibutyryl cAMP- and progesterone-induced corticosterone production was higher in A(y)/a mice than in a/a mice (P<0.001 for dibutyryl cAMP and P<0.01 for progesterone; ANOVA). CONCLUSIONS: Ectopic AP overexpression increased stimulated corticosterone production and intracellular steroidogenic enzyme reactivity to cAMP without an effect on AC activity.