骨骼肌源性抑瘤物的体外初步研究

目的 观察骨骼肌细胞条件培养液（MCM）体外对肿瘤细胞增殖的影响,并初步分析骨骼肌源性抑瘤物的理化特性及抑瘤机理。方法 用噻唑蓝分析法（MTT法）分析新生大鼠MCM对不同肿瘤细胞系的体外抑瘤作用。用超滤分离、热灭活处理、胰酶消化、凋亡分析及形态学观察分析骨骼肌源性抑瘤物的理化特性及抑瘤机理。结果 MCM与哺乳动物源性肿瘤细胞（小鼠骨髓瘤SP2／0及Wistar大鼠癌内瘤Salker256)、人源性白血病细胞（人慢性粒细胞白血病K562及人急性淋巴细胞白血病HL60）、实体瘤细胞（人结肠腺癌细胞LS－174－T及人前列腺癌细胞PC3－M）,以及不同转移潜能肺癌细胞（人肺癌低转移株PLA801－C及人肺癌高转移株PLA801－D）共同培养后,肿瘤细胞的增殖显著下降（P＜0．01－0．05）,且肿瘤细胞增殖呈不同程度MCM浓度依赖性。MCM与正常细胞（兔关节骺板细胞RGP－2）共同培养后,细胞增殖无下降。同一来源肺癌细胞,在MCM稀释至原液的6．25％时,仍见高转移株增殖显著受抑（P＜0．01－0．05）,而在MCM稀释至原液的25％时,低转移株增殖即无显著受抑。MCM的抑瘤活性存在于分子量10000以下超滤组分,热灭活后活性消失,胰蛋白酶消化后活性人存在。MCM不引起K562细胞凋亡,而导致肿瘤细胞膜变粗糙,出现空泡,甚至胞膜消失。结论 新生大鼠骨骼肌细胞可产生特异性抑制人及哺乳动物肿瘤细胞增殖的抑瘤物,其分子量≤10000,对热不稳定而对胰蛋白酶稳定,其抑瘤活性系通过直接损伤瘤细胞膜而非导致瘤细胞凋亡实现的。这种骨骼肌源性抑瘤物可能是临床上骨骼肌转移瘤罕见性现象的关键因素。     

Inhibitory effects of alprazolam on the enhancement of lung metastases induced by operative stress in rats

Experiments were performed in order to evaluate the effects of alprazolam (I mg/kg s.c.), a central benzodiazepine agonist anxiolytic, on the development of lung metastases in rats subjected to laparotomy and injected (i.v.) with 10(4) Walker 256 (W-256) carcinosarcoma cells. The number of metastatic nodules on the surface of the lungs, as well as the percentage-area of metastases in the frontal section through pulmonary hilus were increased in rats subjected to sham-surgery or laparotomy. Treatment with alprazolam partially reversed those adverse effects of surgery, but the difference was clearer when it was administered before surgery was performed. Survival periods were also assessed and alprazolam was found to decrease the lethality of rats exposed to surgery. Pretreatment with Ro 15-1788, a central benzodiazepine antagonist, suppressed the inhibitory effects of alprazolam on tumor growth.     

Effects of antiplatelet agents alone or in combinations on platelet aggregation and on liver metastases from a human pancreatic adenocarcinoma in the nude mouse

There is ample evidence to suggest that hematogenous metastasis may be related to the ability of tumor cells to promote aggregation of host platelets. Arachidonic acid metabolism in platelets and vessel walls may also contribute to the metastatic process. Several preliminary trials of platelet inhibitory agents have been performed. Ketoconazole (inhibitor of lipoxygenase and thromboxane synthetase), verapamil (calcium antagonist), forskolin (stimulator of platelet adenylate cyclase), and indomethacin (inhibitor of cyclooxygenase) were examined, alone and in combination, to investigate their effects on platelet aggregation and on hepatic metastases from human pancreatic tumor cells (RWP-2) in nude mice. The tumor cells were injected intrasplenically, and the animals were divided into control, single-drug and combination treatment groups. The agents were administered intraperitoneally 1 hr before and every 24 hr after the tumor cell injections for 6 days. Statistically significant differences were observed between the control and single-treatment groups on the reduction of liver tumor nodules (range P less than 0.001-0.032) and in the liver surface areas occupied by tumor (range P less than 0.001-0.013). Furthermore, when these agents were combined, similar reductions in liver tumor nodules were noted (range P less than 0.001-0.008), while even greater inhibitory effects were seen in the liver surface areas occupied by tumor (P less than 0.001) compared with the single-treatment groups. Also, the combination studies strongly inhibited RWP-2-induced platelet aggregation in human platelet-rich plasma.     

Inhibition of pulmonary metastasis by Nocardia rubra cell wall skeleton, with special reference to macrophage activation

The antimetastatic activity of Nocardia rubra cell wall skeleton (N-CWS) with or without cyclophosphamide was examined in an experimental model of pulmonary metastasis induced by Lewis lung carcinoma in C57BL/6 mice. Lewis lung carcinoma cells were implanted into the footpads of mice, and the implanted tumors were removed 9 to 10 days later. Pulmonary metastatic nodules began to develop a few days after the implanted tumor was removed. The inhibitory effect of N-CWS was evaluated from the number of pulmonary surface nodules about 3 weeks after tumor implantation. The antimetastatic activity of N-CWS depended upon the dose, time, and route of its injection. Injection of N-CWS i.v. after removal of the implanted tumor caused the greatest inhibition of development of pulmonary metastases. Therapy with N-CWS plus cyclophosphamide prolonged significantly the survival of mice with metastases. The cytotoxic activities of peritoneal macrophages and macrophages in the lung against Lewis lung carcinoma cells were enhanced in mice treated with N-CWS. Injection i.v. of peritoneal macrophages activated with N-CWS inhibited pulmonary metastases. The role of macrophages in inhibition of micrometastasis in the lung is discussed.     

The influence of Fluosol-DA on the occurrence of lung metastases in Lewis lung carcinoma and B16 melanoma

The development of lung metastases from subcutaneously implanted tumors or the development of lung nodules from intravenously injected tumor cells are model systems for metastases formation. Animals bearing subcutaneous Lewis lung tumors (50-100 mm3) were treated with a single dose of Fluosol-DA followed by 1 h of breathing carbogen or maintenance in air. Their lungs were examined for metastases 25 or 40 days after tumor cell implantation. Treatment with Fluosol-DA and carbogen or air breathing reduced by almost 4-fold the number of lung metastases seen. The addition of Fluosol-DA with air or carbogen breathing to treatment of the tumor-bearing limb with 20 Gy reduced the number of lung metastases by 2-fold compared to radiation treatment alone. If Fluosol-DA was administered immediately before or up to 3 days prior to an intravenous challenge with Lewis lung tumor cells, there was a 2- to 3-fold reduction in the number of lung nodules formed. Fluosol-DA administered immediately before or up to 4 days prior to B16 melanoma cells caused a 2- to 3-fold reduction in the number of lung nodules observed. The vascular endothelial cell monolayer adhesion assay was used to test the effects of prior exposure to Fluosol-DA on the attachment of radiolabelled B16 melanoma cells in vitro. There was a trend toward increasing attachment of B16 cells to the endothelial monolayer with prior exposure to increasing concentrations of Fluosol-DA; however, this difference did not reach statistical significance.     

Inhibition of pulmonary metastasis of Lewis lung carcinoma by a glucan, Schizophyllan

The effect of a glucan, Schizophyllan (SPG), on pulmonary metastases in syngeneic mice bearing Lewis lung carcinoma (3LL) was examined. As a model of pulmonary metastases, 3LL cells were implanted into the footpads of C57BL/6 mice, the resulting primary tumor was removed 9-10 days later. The inhibitory effect of SPG was evaluated from the number of pulmonary surface nodules on the lungs about 3 weeks after tumor implantation. SPG was found to have antimetastatic activity, which depended on its dose and time of injection. A single injection of 100 or 200 mg/kg or daily injections of 20 or 50 mg/kg of SPG after removal of the primary tumor markedly inhibited pulmonary metastases. Combined therapy with cyclophosphamide and SPG significantly prolonged the survival of mice with pulmonary metastases. Enhancement of the in vitro cytotoxic activity of peritoneal macrophages and bronchoalveolar or whole lung cells against 3LL cells was noted in SPG-treated mice on day 7 after a single intraperitoneal injection of 100 mg/kg SPG. Intravenous transfer of peritoneal macrophages activated with SPG inhibited the development of pulmonary micrometastases.     

Effects of prostacyclin on tumor cell-induced platelet aggregation

Prostacyclin has been evaluated for its ability to inhibit tumor cell-induced platelet aggregation (TCIPA) induced by several rodent tumor lines: B16a (melanoma); 3LL (carcinoma); 15091A (adenocarcinoma); and W256 (carcinosarcoma). Aggregation of human platelets by all four lines was inhibited by prostaglandin I2 (PGI2) in a dose-dependent manner, with complete inhibition observed at 10 ng/ml. However, higher PGI2 concentrations were required to inhibit aggregation of homologous rat platelets induced by W256 cells. Prostacyclin was compared to other icosanoids known to inhibit platelet aggregation and was found to be 100-fold more potent than either prostaglandin E1 or prostaglandin D2 and 1000-fold more potent than its stable nonenzymatic metabolite (6-ketoprostaglandin F1 alpha). Prostaglandin E2 in contrast to prostaglandin E1 and prostaglandin D2, did not inhibit TCIPA; however, both prostaglandin E2 and its enzymatic metabolite (13,14-dihydro-15-ketoprostaglandin E2) prevented PGI2 inhibition of TCIPA. The addition of prostaglandin I2 (100 ng/ml) after initiation of TCIPA (50% of maximum response) resulted in immediate arrest of TCIPA followed by reversal of platelet aggregation. Prostacyclin partially reversed platelet aggregation when added at 100% of maximum response. Platelets enhanced the adhesion of [125I]uridine-labeled W256 cells to plastic culture dishes under both aggregatory and nonaggregatory conditions. Prostacyclin in vitro inhibited platelet-facilitated tumor cell adhesion. These in vitro results demonstrated that PGI2 is a potent inhibitor of TCIPA and of tumor cell adhesion; we suggest that these are possible mechanisms to explain the antimetastatic effects of PGI2 in vivo [Honn, K. V., Cicone, B., and Skoff, A. Science (Wash. D.C.), 212: 1270-1272, 1981].     

Stimulatory effects of amphetamine on the development of Walker-256 carcinoma lung metastases in rats

Experiments were performed in order to evaluate the effects of amphetamine (0.4 mg/kg/day) on the development of lung metastases in rats injected i.v. with 10(4) Walker 256 (W-256) carcinosarcoma cells, The number of metastatic nodules on the surface of the lungs, as well as the percentage-area of metastases in the frontal section through pulmonary hilus were increased in rats injected with amphetamine in comparison with those injected with placebo. Survival periods were also assessed and amphetamine was found to increase the lethality of rats.     

Lack of effect of in vivo prostacyclin on the development of pulmonary metastases in mice following intravenous injection of CT26 colon carcinoma, Lewis lung carcinoma, or B16 amelanotic melanoma cells

Honn et al. [Science (Wash. DC), 212: 1270, 1981] have recently reported a 93% reduction in the development of metastases of B16 amelanotic tumor cells given i.v. following a single dose of prostacyclin (PGI2) (100 micrograms) and theophylline (100 micrograms) 30 min prior to the injection of tumor cells. We have been unable to reduce pulmonary metastases induced by the i.v. injection of CT26 colon adenocarcinoma, Lewis lung carcinoma, or B16 amelanotic melanoma cells with a similar regimen. Thus, PGI2 and theophylline given prior to injection of tumor cells and 2 hr postinjection had no effect on the number or volume of pulmonary tumor nodules for CT26 cells, using 15 experimental and 14 control animals; Lewis lung cells, using 14 experimental and 13 control animals; or B16 amelanotic cells, using 26 experimental and 12 control animals. The PGI2 used was shown to be active in vitro, inhibiting tumor-induced platelet aggregation by all three tumors at 10(-9)M; and in vivo by inhibition of Lewis lung-induced thrombocytopenia at 1 hr, using 100 micrograms PGI2 prior to the injection of tumor cells.     

GROWTH OF A LOCAL TUMOR EXERTS A SPECIFIC INHIBITORY EFFECT ON PROGRESSION OF LUNG METASTASES

The effects of local tumor growth on the progression of lung metastasis of two mouse tumors of C57BL origin—the 3LL Lewis lung carcinoma and the B-16 melanoma—were studied. Excision of primary footpad grafts of 3LL or B-16 resulted in a significant increase in incidence and size of lung metastases. The incidence, but not the size, of lung metastases was found to be a function of size of the local tumor at time of excision. Reinoculation of tumor cells in the left footpad following excision of tumor from the right footpad suppressed the acceleration of growth of lung metastases and their increased incidence. Thus, the progression of the local tumor exerts an inhibitory effect on lung metastasis. The extent of inhibition of accelerated metastatic development by reinoculated tumor cells is a function of size of the cell inoculum or, in fact, of mass of the local tumor. The inhibitory effect of the local tumor on lung metastasis seems to be tumor-specific. 3LL metastases were not inhibited by local B-16 or EL4, neither was B-16 metastasis inhibited by 3LL. The specificity of interactions between the local tumor growth and its metastases may suggest the participation of immunological mechanisms in the control of lung metastasis. The involvement of the lymphoid system in the control of metastatic progression is also supported by the observation that total-body X-irradiation was associated with an increase in lung metastasis and that splenomegaly was observed in mice bearing the footpad tumor. Its excision resulted in the prevention of splenomegaly but reinoculation of the tumor, leading to metastatic suppression, was again associated with splenomegaly.     

Suppression of experimental lung colonization of a metastatic variant of murine colon adenocarcinoma 26 by a monoclonal antibody 8F11 inhibiting tumor cell-induced platelet aggregation

We have previously established and characterized two monoclonal antibodies, 8F11 and 20A11, that recognize an Mr 44,000 membrane glycoprotein of metastatic murine colon 26 cells. Both monoclonal antibodies inhibit platelet aggregation induced by the tumor cells in vitro. In this report, the inhibitory effect of 8F11 on lung colonization of i.v.-inoculated tumor cells was examined. The i.v. administration of 8F11 suppressed lung colonization of NL-17, a highly metastatic variant of colon 26. Inhibition of NL-17 lung colonization by 8F11 was dose dependent with a maximum of 80% inhibition at a dose of 800 micrograms 8F11/mouse. 8F11 did not inhibit metastases at doses lower than 100 micrograms/mouse. Inhibition of pulmonary metastases by 8F11 was greatest when the antibody was administered 2 h before tumor inoculation. The effect was diminished when the antibody was given 2 h after tumor inoculation. The pulmonary retention of i.v.-inoculated radiolabeled NL-17 cells was decreased by 8F11. F(ab')2 fragments of 8F11 also effectively inhibited lung colonization by NL-17 cells, suggesting that mechanisms unrelated to immune-mediated destruction are involved. These results indicate that the monoclonal antibody 8F11 suppresses the lung colonization of NL-17 cells by interfering with the initial arrest of tumor cells in the lung vasculature through the inhibition of tumor cell-platelet interaction.     

Role of plasma,platelets, and endothelial cells in tumor metastasis

Summary This review studies interactions of tumor cells with a particular host system which is normally responsible for hemostasis and the physiological integrity of the blood vessel luminal surface. With malignancy components of this system are frequently activated, producing abnormalities of blood coagulation, increased platelet responses, and conditions favoring tumor growth and metastasis. Activation of the clotting cascade is mediated by tumor and macrophage procoagulants, acting via Factor X or VII. Thrombin and fibrin are formed. Thrombin also interacts with platelets and the endothelium, potentiating or decreasing coagulation. Generation of thrombin or other tumor mechanisms activate platelets, leading to direct aggregation or secretion of ADP, serotonin, and/or intermediates of the arachidonate metabolism. Vascular lesions caused by tumor attack, platelet secretion, or exogenous agents promoting metastasis may also activate the hemostatic system. It is not yet fully understood how activation of the clotting system, including platelets, contributes to metastasis. Secretion of platelet products appears, however, to be heavily involved. Based on putative mechanisms of action, anticoagulants, platelet inhibitors, thrombocytopenic or vascular repairing agents have been used to control tumor spread. Results depended on the agent and experimental model of metastasis used. Except for coumarin, which was beneficial even against spontaneous metastases, other anticoagulants and platelet inhibitors, excluding perhaps Nafazatrom, gave equivocal results. Thrombocytopenic agents, However, were effective in every tumor system and with any experimental model of metastasis, indicating that platelets play a role in this process. Also consistent were the inhibitory effects of leech salivary gland extract (probably a vascular repairing agent) against lung tumor colonization promoted by ionizing radiation, cyclophosphamide, and cortisone.     

Metastases detected at the time of diagnosis of primary pediatric extremity osteosarcoma at diagnosis: imaging features.

BACKGROUND: The authors performed a retrospective study to estimate the incidence rate of metastatic disease at the time of diagnosis of extremity osteosarcoma (OS), to characterize its pattern of presentation, and to identify factors predictive of survival within a cohort of patients with pulmonary metastatic disease at diagnosis. METHODS: From the institutional solid tumor database, the authors identified all patients diagnosed with extremity OS since CT became available at the study institution (1977). The authors recorded patient demographics, the site of primary disease, the histologic subtype of OS, and the presence of metastases at diagnosis. In those patients with pulmonary metastases at diagnosis, the presence of calcifications, the primary tumor volume, the number of pulmonary lobes with disease, and the number of pulmonary nodules were recorded. RESULTS: Of an evaluable population of 215 patients, 32 (15%) had bone or pulmonary metastases at diagnosis, of whom original imaging from 28 patients was available for review. Osteoblastic histology correlated with lung metastases at diagnosis (P = 0.049). One of the 32 patients had a solitary bone metastasis without lung metastases. Four of 28 patients (14%) with original imaging available had calcifications within the pulmonary nodules. Both the number of nodules and the number of lobes involved were found to be significant predictors of survival (P = 0.0009 and P = 0. 04, respectively); multiple nodules were bilateral in 61% of patients. CONCLUSIONS: The rate of incidence of computed tomography detected pulmonary metastases was found to be 14% (31 of 215 patients) at diagnosis and 0.5% (1 of 215 patients) for bone metastases in patients with primary extremity OS. Pulmonary metastases usually are multiple and bilateral and infrequently calcify. The number of nodules and lobes involved are predictors of patient survival.     

Inhibition of Tumor Cell Arrest in Lungs by Antimetastatic Chitin Heparinoid

We have investigated the effect of sulfated chitin derivatives on the intravascular events in the metastatic cascade. 6-O-Sulfated carboxymethyl chitin (SCM-chitin III), as well as heparin, significantly inhibited the arrest of B16-BL6 cells in lungs after co-injection with radiolabeled tumor cells, but carboxymethylated chitin (CM-chitin) had no effect. Heparin showed a potent inhibitory effect on tumor cell-elicited platelet aggregation and on blood coagulation, which can subsequently enhance the survival, arrest and invasiveness of tumor cells, whereas SCM-chitin III showed much weaker properties. In contrast, SCM-chitin III was found to inhibit the adhesion of tumor cells to subendothelial matrix, while heparin did not. SCM-chitin III was still active in inhibiting experimental lung metastasis even in mice which had been pretreated with anti-asialo GM1 serum or carrageenan to eliminate NK cells or macrophages. Thus, these results suggest that SCM-chitin-mediated inhibition of tumor metastases is distinct from that by heparin and may be due to interference with tumor cell arrest in the capillaries and consequently to the inhibition of tumor cell adhesion to subendothelial matrix.     

Protective effects of WR-2721 against radiation-induced injury of murine gut, testis, lung, and lung tumor nodules

WR-2721 (S-2-(3 aminopropylamino) ethylphosphorothioic acid) has been investigated for its ability to protect gut, lung, and testis, as well as fibrosarcoma (FSa) tumor nodules, in the lungs of mice from gamma-radiation injury. This compound greatly protected jejunum and testis epithelial cells. FSa micrometastases in the lung were protected to a lesser extent than jejunum and testis. Conversely, WR-2721 was not able to protect the lung against radiation-induced enhancement of tumor metastases formation generated by intravenously injected FSa cells.     

Inhibition of tumor cell arrest in lungs by antimetastatic chitin heparinoid

We have investigated the effect of sulfated chitin derivatives on the intravascular events in the metastatic cascade. 6-O-Sulfated carboxymethyl chitin (SCM-chitin III), as well as heparin, significantly inhibited the arrest of B16-BL6 cells in lungs after co-injection with radiolabeled tumor cells, but carboxymethylated chitin (CM-chitin) had no effect. Heparin showed a potent inhibitory effect on tumor cell-elicited platelet aggregation and on blood coagulation, which can subsequently enhance the survival, arrest and invasiveness of tumor cells, whereas SCM-chitin III showed much weaker properties. In contrast, SCM-chitin III was found to inhibit the adhesion of tumor cells to subendothelial matrix, while heparin did not. SCM-chitin III was still active in inhibiting experimental lung metastasis even in mice which had been pretreated with anti-asialo GM1 serum or carrageenan to eliminate NK cells or macrophages. Thus, these results suggest that SCM-chitin-mediated inhibition of tumor metastases is distinct from that by heparin and may be due to interference with tumor cell arrest in the capillaries and consequently to the inhibition of tumor cell adhesion to subendothelial matrix.     

9-Nitrocamptothecin liposome aerosol treatment of melanoma and osteosarcoma lung metastases in mice.

The response rates of relapsed osteosarcoma and melanoma pulmonary metastases to traditional i.v. chemotherapeutic regimens have been disappointing. Direct drug delivery of chemotherapy to the lungs could increase the drug concentration in the tumor area and may offer a new therapeutic approach for these patients. Previous studies demonstrated that drugs delivered to the respiratory tract in liposomal formulation resulted in high pulmonary drug concentration, reduced systemic toxicity, and reduced dosage requirements compared with parenteral and oral administration. To determine whether this approach has utility against pulmonary metastases, the efficacy of aerosol therapy with liposome-encapsulated 9-nitrocamptothecin (L-9NC) was determined using two different experimental lung metastasis models. C57BL/6 mice were treated the day after the i.v. injection of B16 melanoma cells with aerosol L-9NC for 1 h (153 microg 9-nitrocamptothecin/kg) for 5 days per week for up to 3 weeks. Aerosol L-9NC treatment resulted in a reduction in lung weights (P = 0.005) and number of tumor foci (P < 0.001). Visible tumor nodules were fewer and smaller in the 9-nitrocamptothecin-treated group than in untreated control mice (P < 0.001). Using a newly developed human osteosarcoma experimental metastasis model in nude mice, we demonstrated that aerosol L-9NC was also effective against established lung metastases. Aerosol therapy initiated on the ninth week after i.v. tumor injection and continued for 8 or 10 weeks produced highly significant reductions in the number of animals with both visible and microscopic disease (P < 0.02), the total number of tumor foci in the lungs (P < 0.005), and the size of the individual tumor nodules (P < 0.02). These data suggest that L-9NC aerosol therapy may offer significant advantage over existing methods in the treatment of melanoma and osteosarcoma pulmonary metastases.     

Platelet-tumor-cell interactions in mice. The role of platelets in the spread of malignant disease

Thrombocytopenia reduces the number of metastases produced by a wide variety of murine tumors. Studies aimed at investigating interactions between tumors and platelets reveal that many tumors aggregated platelets in vitro and/or produced thrombocytopenia in vivo. In some instances, tumor-cell-induced thrombocytopenia in vivo was accompanied by accumulation of platelets in the lung. Thrombocytopenia was most active against metastases produced by tumors with the capacity to aggregate platelets in vitro and/or in vivo but it was also effective against metastases produced by tumors lacking such a capacity. Further studies, aimed at increasing platelet aggregation in vivo, as when fibroblasts were added to the tumor inoculum, or decreasing the platelet response to aggregating agents, as when aspirin was administered to mice, strongly support the role of platelet aggregation and the platelet release reaction in metastasis. As expected, fibroblasts enhanced while aspirin decreased tumor spread, the latter being equally effective against both artificially induced and spontaneously-occurring metastases. Formation of platelet aggregates not only enhances but also seems to change the distribution of metastases. Tumors with platelet aggregating capacities usually give lung metastases while those devoid of such a capacity may show metastases of widespread distribution. Research with ¹²⁵IUDR-labelled B16 melanoma cells indicates that thrombocytopenia does not affect the initial vascular arrest of tumor cells but seems to influence their subsequent retention by the lung.     

p53C末端356～393氨基酸对人肺癌细胞恶性表型的影响

目的　研究去除C末端 3 56～ 3 93氨基酸p53对人肺癌细胞恶性增殖抑制的影响。方法利用DNA重组技术 ,构建去掉C末端 3 56～ 3 93区 3 7个氨基酸残基p53和全长p53真核细胞表达质粒[pEGFP p53 (del) ,pEGFP p53 ]。p53缺失和突变的人肺癌细胞系 80 1D为受体细胞 ,lipofectin介导质粒转染细胞。G418筛选 ,建立转染克隆细胞系。以PCR、荧光显微镜检查外源基因的表达 ;以集落形成和裸鼠移植瘤试验检测细胞体内外恶性增殖能力 ;以移植瘤或接种部位细胞团印片检查荧光蛋白表达。结果　建立了转染克隆细胞系pEGFP p53 80 1D、pEGFP p53 (del) 80 1D和pEGFP 80 1D ,证明有外源p53基因存在和外源绿色荧光蛋白基因表达。pEGFP p53 (del) 80 1D体外集落形成抑制率为 99.6% ,pEGFP p53 80 1D为 81.1% ,pEGFP p53 (del) 80 1D细胞恶性增殖能力明显低于pEGFP p53 80 1D (P <0 .0 1)。pEGFP p53 (del) 80 1D形成的少数集落也有外源p53基因和绿色荧光蛋白表达。裸鼠移植瘤试验显示 ,对照组 80 1D和pEGFP 80 1D移植瘤为阳性 (4/ 4,4/ 4) ,pEGFP p53 (del) 80 1D和pEGFP p53 80 1D移植瘤为阴性 ,接种细胞部位仍有残留细胞团存在 ,有少数表达荧光蛋白的活细胞。结论去除C末端 3 56～ 3 93氨基酸的p53 ,在体外可明显     

Modulation of lung tumor colony formation by a subcutaneously growing tumor

When monodisperse tumor cell suspensions of the mouse sarcoma L1 were injected iv into inbred BALB/c mice bearing subcutaneous grafts of the same tumor, the number of tumor nodules developing in the lungs was highest in animals bearing the oldest primary tumor (28 days) and lowest in animals bearing the oldest primary tumor (28 days) and lowest in animals bearing 16-day-old primary tumors. The number of metastases developing in mice bearing 9-day-old subcutaneous tumors was the same as that in control animals without a subcutaneous tumor. This state of low and high susceptibility to lung metastases can be transferred from tumor-bearing mice to whole-body irradiated mice by means of spleen cells, and this transfer of susceptibility is stable for at least 3 weeks. The results indicate a) that a growing subcutaneous tumor can modulate the number of artificial metastases occurring in the lungs as a result of the iv injection of tumor cells, and b) that this modulation occurs by immune mechanisms. In the model presented here, the host is first protected and then made more susceptible to artificial lung metastases by the presence of a progressively growing subcutaneous tumor.