Betulinic acid augments the inhibitory effects of vincristine on growth and lung metastasis of B16F10 melanoma cells in mice

We examined the antitumour effect of a combination of betulinic acid (BA) and vincristine (VCR) on murine melanoma B16F10 cells in vitro and in vivo. Betulinic acid, a pentacyclic triterpene, showed a synergistic cytotoxic effect on melanoma cells by combinational use of VCR. Betulinic acid and VCR induced cell cycle arrest at different points (BA at G1 phase and VCR at G2/M phase) and caused apoptosis in B16F10 melanoma cells. In the in vivo study, VCR inhibited metastasis of tumour cells to the lung. The addition of BA to VCR augmented suppression of the experimental lung metastasis of melanoma cells in C57BL/6 mice. The number of lung nodules of more than 1 mm in diameter in mice treated with BA and VCR was less than that in mice treated with VCR alone. These results suggest that BA is an effective supplement for enhancing the chemotherapeutic effect on malignant melanoma.     

Immunochemical localization of heparanase in mouse and human melanomas

Heparanase, an endo-beta-D-glucuronidase, has been associated with melanoma metastasis. Polyclonal antibodies directed against the murine N-terminal heparanase peptide detected a Mr approximately 97,000 protein on SDS-PAGE of mouse melanoma and human melanoma cell lysates. In an indirect immunocytochemical study, human A375-SM and mouse B 16-BL6 melanoma cells were stained with the anti-heparanase antibodies. Heparanase antigen was localized in the cytoplasm of permeabilized melanoma cells as well as at the cell surface of unpermeabilized cells. Immunohistochemical staining of frozen sections from syngeneic mouse lungs containing micrometastases of B16-BL6 melanoma demonstrated heparanase localized in metastatic melanoma cells. Similar studies using frozen sections of malignant melanomas resected from patients indicated that heparanase is localized in invading melanoma cells. Our studies suggest that (a) the N-terminus of the heparanase molecule in mouse and human is antigenically related; (b) heparanase antigens are localized at the cell surface and in the cytoplasm of metastatic human and mouse melanoma cells; and (c) heparanase antigens are enriched in invasive and metastatic murine and human melanomas in vivo.     

Influence of nitric oxide synthase II gene disruption on tumor growth and metastasis

The relationship between nitric oxide (NO) synthase II (NOS II) expression and the metastatic ability of tumor cells is inconclusive. We determined the role of host NOS II expression in the growth and metastasis of the B16-BL6 murine melanoma and M5076 murine ovarian sarcoma cell lines. The cells were either s.c. or i.v. injected into syngeneic wild-type (NOS H+/+) and NOS II-null (NOS H-/-) C57BL/6 mice. Both cell lines produced slightly larger s.c. tumors in NOS H-/- mice than in NOS II+/+ mice. However, B16- BL6 cells produced more and larger experimental lung metastases in NOS II+/+ mice than in NOS II-/- mice, whereas M5076 cells produced fewer and smaller experimental lung metastases in NOS II+/+ mice than in NOS II-/- mice. After activation with IFN-gamma and lipopolysaccharide, macrophages isolated from NOS II+/+ C57BL/6 mice produced NO-dependent cytotoxicity in sarcoma cells, whereas macrophages from NOS II-/- C57BL/6 mice did not. In contrast, activated macrophages produced little to no NO-mediated cytotoxicity in melanoma cells. Immunostaining analyses indicated that NOS II expression was apparent in the metastases growing in NOS H+/+ mice and correlated with increased cell proliferation in B16-BL6 lung metastases but with decreased cell proliferation in M5076 liver metastases. Our data suggest that disruption of host NOS II expression enhanced the growth and metastasis of NO-sensitive tumor cells but suppressed the metastasis of NO-resistant tumor cells, proposing that host-derived NO may differentially modulate tumor progression.     

Effect of thrombin treatment of tumor cells on adhesion of tumor cells to platelets in vitro and tumor metastasis in vivo.

Seven different tumor cell lines (human melanoma SK MEL 28; hamster melanoma HM29; murine melanomas B16F10 and amelanotic melanoma B16a; human colon carcinoma HCT8; murine colon carcinoma CT26; and murine Lewis lung carcinoma) were treated with thrombin at 0.5-1 unit/ml and examined for their ability to bind to adherent platelets; HM29 was studied for its ability to bind to fibronectin and von Willebrand factor; CT26, B16F1, B16F10, and B16a were studied for their ability to form pulmonary metastasis after i.v. injection of thrombin-treated tumor cells; CT26 was studied for its ability to grow s.c. Five of 7 thrombin-treated tumor cell lines increased their adhesion to adherent platelets 2-to 3-fold. HM29 increased its adherence to fibronectin and von Willebrand factor 2- to 3-fold. CT26, B16F1, B16F10, and B16a increased experimental pulmonary metastasis 10- to 156-fold. Thrombin-treated CT26 cells demonstrated 2-fold greater growth in vivo after s.c. injection. The mechanism of enhanced adhesion of thrombin-treated tumor cells to platelets required the platelet integrin GPIIb-GPIIIa since it could be inhibited by agents known to block adhesion of ligands to GPIIb-GPIIIa (monoclonal antibody 10E5, tetrapeptide RGDS, disintegrin Albolabrin); as well as a "GPIIb-GPIIIa-like" structure on tumor cells since it could be inhibited by treatment of thrombin-treated tumor cells with 10E5 and RGDS. The thrombin effect on tumor cells was optimum at 1 h of incubation with thrombin, did not require active thrombin on the tumor cell surface, and did not require protein synthesis (not inhibited by cycloheximide). Thus, thrombin-treated tumor cells markedly enhance pulmonary metastasis. It is suggested that this may be secondary to thrombin-induced enhanced adhesion as well as growth of tumor cells.     

Monoclonal antibody 4C5 immunostains human melanomas and inhibits melanoma cell invasion and metastasis.

PURPOSE: Tumor cell metastasis constitutes a major problem in the treatment of cancer. Because the cure rate of metastatic tumors is very low, new therapeutic approaches are needed. Heat shock protein 90 (HSP90) is a molecular chaperone that is recognized as a new target for the treatment of cancer. Here, we examine the value of a monoclonal antibody (mAb) against HSP90, mAb 4C5, as a potential marker in malignant melanomas. Moreover, we investigate the possibility to use mAb 4C5 as an inhibitor of melanoma cell invasion and metastasis. EXPERIMENTAL DESIGN: Paraffin blocks of formalin-fixed human melanoma tumor tissues were used to prepare tissue microarrays. The B16 F10 melanoma cell line was used in all the in vitro experiments. To assess melanoma cell invasion, the wound-healing assay and the Matrigel invasion assay were applied. To evaluate the effect of mAb 4C5 on tumor metastasis, we used an experimental model of metastatic melanoma. RESULTS: Immunohistochemical studies done on a panel of malignant melanomas showed positive immunostaining with mAb 4C5 in all cases. mAb 4C5 inhibits B16 F10 cell invasion by binding to surface HSP90 because it is not internalized. mAb 4C5 significantly inhibits melanoma metastasis in C57BL/6 mice inoculated with B16 F10 cells. CONCLUSIONS: mAb 4C5 could be potentially used as a novel specific marker for malignant melanomas. mAb 4C5 inhibits melanoma cell invasion in vitro by binding to cell surface HSP90 expressed on B16 F10 melanoma cells. Finally, this antibody significantly inhibits melanoma metastasis, thus rendering it a potential therapeutic agent for the treatment of cancer metastasis.     

Effect of interleukin-1-beta on metastasis formation in different tumor systems

Experiments were done to determine the effect of interleukin-1-beta (IL-1 beta) on metastasis formation in different tumor systems. Intravenous administration of 1 microgram of human recombinant IL-1 beta given 1 hour before tumor cell injection augmented lung colony formation (experimental metastases) by the human A375 melanoma variants, the human HT-29M colon carcinoma, the SN12-K1 renal carcinoma in nude mice, the murine B16 melanoma variants, and the murine UV-2237M fibrosarcoma in syngeneic recipients. The same treatment did not induce lung colony formation by a human rectal carcinoma (HCC-P2988) or by a murine reticulum cell sarcoma (M5076), both of which are not metastatic to the lung. Spontaneous metastases were studied in C57BL/6 mice bearing the B16-BL6 melanoma (metastatic to the lung) in their footpad and the M5076 reticulum cell sarcoma (metastatic to the liver) subcutaneously. Daily intraperitoneal treatment with 1 microgram of IL-1 beta increased lung and liver metastases. These findings indicate that treatment of mice with IL-1 beta can increase the number of artificial or spontaneous metastases and that this effect is not limited to a single tumor type or to a specific organ.     

Inhibition of invasion,gelatinase activity,tumor take and metastasis of malignant cells by N-acetylcysteine

The thiol N-acetylcysteine (NAC) is currently considered one of the most promising cancer chemopreventive agents by virtue of its multiple and coordinated mechanisms affecting the process of chemical carcinogenesis. Recent studies have shown that an unpaired cysteine residue in the propeptide plays a key role in inactivation of latent metastasis-associated metalloproteinases: the present study was designed to assess whether NAC could also affect tumor take, invasion and metastasis of malignant cells. As assessed by zymographic analysis, NAC completely inhibited the gelatinolytic activity of type-IV collagenases in the cells tested (gelatinases A and B). Moreover, NAC was efficient in inhibiting the chemotactic and invasive activities of tumor cells of human (A2058 melanoma) and murine origin (K1735 and B16-F10 melanoma cells as well as C87 Lewis lung carcinoma cells) in Boyden-chamber assays, which are predictive of the invasive and metastatic properties. Reduced glutathione (GSH) had a similar, although less effective activity. The number of lung metastases decreased sharply when B16-F10 murine melanoma cells, injected i.v. into nude mice, were pre-treated with NAC and resuspended in medium supplemented with 10 mM NAC. In other experiments NAC was given in drinking water, starting 48-72 hr before subcutaneous inoculation of either B16-F10 cells or of their highly metastatic variant B16-BL6, or intramuscular injection of LLC cells. In all experiments NAC treatment decreased the weight of the locally formed primary tumor and produced a dose-related delay in tumor formation. Spontaneous metastasis formation by B16-F10 and B16-BL6 tumors was slightly yet significantly reduced by oral administration of NAC. However, this was not observed for Lewis lung tumors. These data indicate that NAC affects the process of tumor-cell invasion and metastasis, probably due to inhibition of gelatinases by its sulfhydryl group, with the possible contribution of other mechanisms, including the potent antioxidant activity of this thiol. © 1995 Wiley-Liss, Inc.     

JAM-C promotes lymphangiogenesis and nodal metastasis in non-small cell lung cancer

This study aims to investigate lymphatic metastasis-related genes in non-small cell lung carcinomas (NSCLC). NSCLC tissue was analyzed for expression of junctional adhesion molecule-C (JAM-C) protein. Our data revealed novel associations between JAM-C overexpression in primary tumors and lymphatic microvessel density (LMVD), lymph node metastasis, and poorer overall survival and recurrence-free survival. We used the highly metastatic human lung adenocarcinoma cell line Anip973 and its parental line AGZY83-a, which has a low metastatic capacity, in vivo and vitro. We found that JAM-C played an important role in different metastasis capacity of lymph node. JAM-C affected tumor growth, LNM, JAM-C, VEGF-C, vasculature, and ERK1/2 phosphorylation (p-ERK1/2). β1 integrin was involved in lymph node metastasis. Moreover, JAM-C knockdown in highly metastatic Anip973 decreased cell migration in scratch-wound assays. The JAM-C knockdown in Anip973 cells and JAM-C cDNA in AGZY83-a cells regulated the vascular endothelial growth factor C (VEGF-C) expression. Immunofluorescence showed that blocked VEGF-C expression in JAM-C shRNA Anip973 cells were restored after JAM-C treatment. JAM-C-induced VEGF-C in JAM-C cDNA AGZY83-a cells was also effectively inhibited by treatment with an antibody specifically against JAM-C. Use of media from Anip973 cells, AGZY83-a, and A549cells lung cancer cells that overexpressed or downregulated JAM-C was demonstrated to affect activity of VEGF-C-induced β1 integrin subunit or ERK activity in human dermal lymphatic endothelial cells (HDLEC) treated with VEGF-C or inhibitory antibody to JAM-C. Overall, these results indicate that JAM-C could mediate metastasis as it contributes to VEGF-C expression in cancer cells. JAM-C affects β1and ERK activation in HDLEC, thus promoting lymphangiogenesis and nodal metastasis. Our findings indicate that JAM-C may be a therapeutic target for preventing and treating lymphatic metastases.     

Preclinical evaluation of the antineoplastic efficacy of 7-(2-hydroxyethyl)theophylline on melanoma cancer cells

Differentiation-based therapeutics are an underutilized but potentially a significant option for cancer treatment. The effect of methylxanthines on melanoma cell differentiation has been well documented. We report the in-vitro and in-vivo anticancer potential of a theophylline analogue, 7-(2-hydroxyethyl)theophylline (HET), on murine B16-F10 and human Sk-Mel 110 metastatic melanoma cell lines. The effects on cell proliferation were related to the induction of differentiation, demonstrated as increased intracellular transglutaminase activity. The involvement of this methylxanthine in the control of the in-vitro adhesion and in the in-vivo metastastic spread of melanoma cells was further investigated. HET oral administration of C57BL6/N mice intravenously injected with B16-F10 cells markedly reduced lung metastases frequency. The overall results demonstrated that HET possesses a remarkable in-vivo antimetastatic capability.     

Suppression of growth and hepatic metastasis of murine B16FO melanoma cells by a novel nutrient mixture

Highly metastatic melanoma is resistant to existing therapies. Our main objective was to investigate the effect of a nutrient mixture (NM) on B16FO tumor growth and hepatic metastasis. Tumor growth was studied in athymic nude male mice, 5-6 weeks old, inoculated with 10(6) B16FO melanoma cells subcutaneously and fed either a regular diet or one supplemented with 0.5% NM. Four weeks later, the mice were sacrificed and their tumors excised, weighed and processed for histology. Metastasis was studied in C57BL/6 mice, which received 10(6) B16FO melanoma cells by intrasplenic injection, as well as a regular or 0.5% NM-supplemented diet for 2 weeks. Survival was studied in C57BL/6 mice receiving 10(6) B16FO melanoma cells intraperitoneally (i.p.) followed by the regular, NM-supplemented, or regular diet in addition to being administered with 2 mg NM injection 3 times per week. NM inhibited the growth of B16FO melanoma cells by 50%. Lesions in the two groups were consistent with malignant melanoma. Mice were injected with B16FO cells in the spleen. Those fed the regular diet developed large black spleens and livers indicating growth in the spleen and metastasis to the liver. In contrast, mice supplemented with NM showed less growth in spleen, but also reduced metastasis to the liver. The survival time of mice receiving NM supplementation and B16FO cells i.p. was greater than in mice which were fed the regular diet. To confirm effects in vivo, we investigated the effect of NM on murine B16FO melanoma cells in vitro, including cell proliferation by MTT assay, morphology by hematoxylin and eosin (H&E) staining and apoptosis using live green caspase detection kit. In vitro, NM was not toxic at 100 microg/ml concentration, but exhibited 44% toxicity over the control at 500 and 1000 microg/ml. H&E did not indicate any changes up to 100 microg/ml. NM induced slight apoptosis at 100 microg/ml, moderate at 500 and extensive at 1000 microg/ml concentration.     

Severe pulmonary metastasis in obese and diabetic mice

Although obesity is known as a risk factor for several human cancers, the association of obesity with cancer recurrence and metastasis remains to be characterized. Here, B16-BL6 melanoma and Lewis lung carcinoma cells were intravenously injected into diabetic (db/db) and obese (ob/ob) mice. The number of experimental lung colonies was markedly promoted in these mice when compared with C57BL/6 mice. In contrast, tumor growth at the implanted site was comparable when cells were inoculated orthotopically. The use of B16-BL6 cells stably transfected with the luciferase gene revealed that the increased metastasis reflected a difference mainly within 6 hr after the intravenous inoculation of tumor cells. Administration of recombinant leptin in ob/ob mice abolished the increase in metastasis early on as well as the decrease in the splenic NK cell number. In addition, depletion of NK cells by an anti-asialo-GM1 antibody abrogated the enhanced metastasis in db/db mice. These results demonstrate that metastasis is markedly promoted in diabetic and obese mice mainly because of decreased NK cell function during the early phase of metastasis.     

Effective treatment of preexisting melanoma with whole cell vaccines expressing alpha(1,3)-galactosyl epitopes

The hyperacute immune response in humans is a potent mechanism of xenograft rejection mediated by complement-fixing natural antibodies recognizing alpha(1,3)-galactosyl epitopes (alphaGal) not present on human cells. We exploited this immune mechanism to create a whole cell cancer vaccine to treat melanoma tumors. B16 melanoma vaccines genetically engineered to express alphaGal epitopes (B16alphaGal) effectively treated preexisting s.c. and pulmonary alphaGal-negative melanoma (B16Null) tumors in the alpha(1,3)-galactosyltransferase knockout mouse model. T cells from mice vaccinated with B16alphaGal recognized B16Null melanoma cells measured by detection of intracellular tumor necrosis factor-alpha. We showed successful adoptive transfer of immunity to recipient mice bearing lung melanoma metastasis. Mice receiving lymphocytes from donors previously immunized with B16alphaGal had reduced pulmonary metastases. The transfer of lymphocytes from mice vaccinated with control vaccine had no effect in the pulmonary metastasis burden. This study unequivocally establishes for the first time efficacy in the treatment of preexisting melanoma tumors using whole cell vaccines expressing alphaGal epitopes. Vaccination with B16alphagal induced strong long-lasting cell-mediated antitumor immunity extended to B16Null. These data formed the basis for the testing of this therapeutic strategy in human clinical trials currently under way.     

Suramin augments the antitumor and antimetastatic activity of pentoxifylline in B16F10 melanoma

Rapid tumor growth and metastasis are 2 major problems associated with treatment of malignant melanoma. Therefore, drugs that can intervene these processes are of clinical importance. Pentoxifylline (PTX), a methyl xanthine derivative, has been shown to inhibit B16F10 melanoma tumor growth and metastasis. We hypothesized that suramin when combined with PTX enhances its antineoplastic effects, which we have examined using the B16F10 mouse melanoma model. Suramin in simultaneous or sequential combination potentiated the cytotoxic effects of PTX on B16F10 cells. PTX arrested cells in the G0-G1 phase and suramin augmented the effects. Both the drugs inhibited F10 adhesion to laminin, matrigel and collagen type IV and showed enhanced inhibition in combination The combination also demonstrated significantly higher inhibition in cell motility (p = 0.002) and invasion through matrigel (p = 0.005) as compared to the single agents. Suramin synergized with PTX in its effects on secretion of MMP-9 gelatinase. DBA2/J mice implanted with intradermal B16F10 tumor were used as a model to study tumor growth. Animals were intratumorally treated with 50 mg/kg of PTX, 10 mg/kg of suramin and their combinations. Simultaneous administration of the drugs inhibited tumor growth by 5- to 6-folds. Tumor growth was completely blocked in sequential regimen with regression in some cases. The number and size of metastatic nodules on lung was also reduced significantly by the combination treatment. In conclusion, the novel combination of PTX and suramin has synergistic antitumor and antimetastatic activity in B16F10 melanoma and may be a promising approach in treatment of patients suffering from malignant melanoma.     

Simultaneous blockade of VEGFR-1 and VEGFR-2 activation is necessary to efficiently inhibit experimental melanoma growth and metastasis formation

Metastasis continues to be the major cause of morbidity and mortality in malignant melanoma. In our study, we explored whether inhibition of VEGFR-1 or VEGFR-2 signaling conveys distinct suppressive effects on B16 melanoma subcutaneous growth and metastasis formation. The inhibition of VEGFR-1 or -2 alone had no significant influence on both melanoma growth and metastasis formation. In contrast, simultaneous blockade of VEGFR-1 and -2 signaling strongly suppressed progression in both B16 tumor models. There was no expression of VEGFR-1 or -2 detectable on the B16 cells used, excluding the melanoma cells as direct therapeutic targets. Analyzing the contribution of progenitor-like cells during melanoma metastasis formation, we observed an enhanced proliferation and mobilization of VEGFR-1+ myeloid and VEGFR-2+ endothelial cells with progenitor potential by the induction of melanoma lung metastasis, which was not influenced by interference with VEGFR signaling. These results indicate that the antimetastatic effects exerted by combined inhibition of VEGFR-1 and -2 signaling were mediated via targeting cell populations other than progenitors only. Sole inhibition of VEGFR-1 signaling led to a strong reduction of the CD45-positive inflammatory infiltrate in the tumor tissue. However, the formation of lung metastasis was not affected, indicating that inhibition of the inflammatory response was not sufficient to efficiently block B16 melanoma metastasis development. Taken together, our data suggest that in the utilized B16 tumor models the blockade of both the inflammatory and the VEGFR-2-dependent angiogenic response are necessary to effectively inhibit solid tumor growth and formation of lung metastasis by B16 melanoma cells.     

The effect of poly (aspartic acid-co-lactic acid) nanospheres on the lung metastasis of B16BL6 melanoma cells by intravenous administration

Poly (aspartic acid-co-lactic acid) (PAL) has been investigated as a new biodegradable material for Drug Delivery Systems (DDS). Similar to the poly (lactic acid-co-glycolic acid) (PLGA) nanospheres, the PAL nanospheres can control-release encapsulated drugs by hydrolysis and adhere to the mucous membranes to improve the drug absorption. In this study, the vitamin encapsulated PAL nanospheres were applied on mice to examine their effect on tumor metastasis and safety as an injectable DDS material for anti-cancer and other drugs. In the experiment, 6 C57BL/6 mice per group were intravenously administered with B16BL6 melanoma cells (1 x 10(5) per mouse) and non-encapsulated PAL nanospheres or pro-vitamin encapsulated nanospheres respectively, while the control group was administered with B16BL6 cells alone. Two weeks later, the lungs of the mice were excised and metastatic foci on the lung surface were counted. The melanoma cell metastasis to lungs was prevented by intravenous co-injection of B16BL6 melanoma cells with 1.7 microg of pro-vitamin E encapsulated PAL nanospheres. Its metastatic foci count (mean +/- SD) was 127+/-80, which was better than the control (246+/-95, p<0.02). Also, applying the pro-vitamin C and pro-vitamin A encapsulated PAL nanospheres as well as the non-encapsulated PAL nanospheres slightly decreased the number of metastasis colonies in the lungs as compared to that of the control. These results suggested that PAL nanospheres did not promote the lung metastasis of B16BL6 melanoma cells. Thus, the PAL nanospheres are safe material for injection applications.     

Relationship between secreted urokinase plasminogen activator activity and metastatic potential in murine B16 cells transfected with human urokinase sense and antisense genes.

Murine melanoma B16-F1 cells of low metastatic potential were transfected with the human gene for the prepro form of urokinase in an SV40 expression vector (plasmid pSV2-uPA), and cells expressing high amounts of the human urokinase gene product were selected for by an enzyme-linked immunosorbent assay specific for human high molecular weight urokinase. Southern analysis showed one of the cell lines (clone 7) had incorporated 150 copies of the pSV2-uPA plasmid into its genomic DNA. The human urokinase synthesized by the pSV2-uPA-transfected murine B16 cells was found to be glycosylated and did not bind to the murine cell surface urokinase receptor sites. In an in vivo assay that measures metastasis from a primary tumor (spontaneous metastatic assay), clone 7 cells showed an increased ability to metastasize (12 of 12 mice showed metastatic tumors), while control cells showed a lower ability to metastasize (only 2 of 11 mice showed metastatic tumors). In a second in vivo assay, which measures only the steps of the metastatic migration process during which tumor cells extravasate from the blood and then grow into pulmonary tumors (lung colonization assay), a significant multifold increase in the ability to form lung tumors was shown by the high human urokinase-secreting B16-F1 cells. In B16-F10 cells incorporating an antisense sequence to preprourokinase (plasmid pSV1-ASuPA-265) and secreting significantly decreased amounts of murine urokinase, a corresponding significant decrease in lung colonization was observed. These results provide direct experimental support for a role of secreted (non-surface-bound) urokinase in the colonization steps of the metastatic process. Furthermore, the data indicate that the higher lung colonization ability of the B16-F10 line than of the B16-F1 line is primarily based on the quantitative differences in their abilities to produce urokinase.     

苦参碱衍生物M19对于肿瘤细胞转移的抑制作用

目的:探讨苦参碱衍生物M19对于肝细胞癌和黑色素瘤细胞转移的抑制作用。方法:肝癌细胞Hep3B、MHCC-LM3和黑色素瘤细胞B16F10经M19处理后,检测肿瘤细胞体外迁移能力。建立C57BL/6小鼠黑色素瘤B16F10和裸鼠肝细胞癌MHCC-LM3转移模型,经M19体内给药后,观察肿瘤细胞肝、肺转移情况。结果:M19能浓度依赖性地抑制肝癌细胞和黑色素瘤细胞迁移。M19体内给药使B16F10细胞在小鼠肺的转移减少,且还能抑制MHCC-LM3细胞在裸鼠肺和肝的转移。结论:M19能在体内外抑制肝细胞癌和黑色素瘤细胞的转移。     

Genetically fluorescent melanoma bone and organ metastasis models.

We report here the establishment and metastatic properties of bright, highly stable, green fluorescent protein (GFP) expression transductants of the B16 mouse malignant melanoma cell line and the LOX human melanoma line. The highly fluorescent malignant melanoma cell lines allowed the visualization of skeletal and multiorgan metastases after i.v. injection of B16 cells in C57BL/6 mice and intradermal injection of LOX cells in nude mice. The melanoma cell lines were transduced with the pLEIN expression retroviral vector containing the GFP and neomycin resistance genes. Stable B16F0 and LOX clones expressing high levels of GFP were selected stepwise in vitro in levels of G418 of up to 800 microg/ml. Extensive bone and bone marrow metastases of B16F0 were visualized by GFP expression when the animals were sacrificed 3 weeks after cell implantation. Metastases for both cell lines were visualized in many organs, including the brain, lung, pleural membrane, liver, kidney, adrenal gland, lymph nodes, skeleton, muscle, and skin by GFP fluorescence. This is the first observation of experimental skeletal metastases of melanoma, which was made possible by GFP expression. These models should facilitate future studies of the mechanism and therapy of bone and multiorgan metastasis of melanoma.     

Augmentation of metastasis formation by thioglycollate-elicited macrophages

Inoculation of thioglycollate-elicited peritoneal exudate cells (PEC) into C57BL/6 mice reduced the rate of lung clearance of several intravenously (i.v.) injected murine tumor cells, and increased by up to 100-fold the number of artificially-induced metastatic lung nodules produced by the i.v. injection of B16 melanoma or Lewis lung carcinoma (3LL) tumor cells. Maximum effects were observed when PEC were injected either before, or shortly after, tumor cells. Modulation of lung clearance or metastasis formation was observed only with PEC and not with a variety of other cells, such as splenocytes, thymocytes, P815 mastocytoma cells, or several macrophage-like cell lines (PU5-1.8 and IC-21). Lysates of PEC were as efficient in reducing lung clearance and augmenting metastasis formation as were intact viable PEC. Lysates of other cell types, including P815 and the macrophage-like cell lines, were unable to produce these effects. PEC populations, enriched for macrophages by adherence to plastic or by percoll density gradient sedimentation, also increased the number of B16-induced artificial metastasis, implicating the macrophage as the cell responsible for these observations.