Lung adenoma development and NK activity in mice treated with multiple carcinogens.

A wide-spectrum initiation model was investigated in mice. Sequential treatments with diethylnitrosamine, urethane and N-methylnitrosourea, with or without a promoter, phenobarbital, resulted in tumor formation in the lungs in 85-90% of animals, but did not produce any tumorous lesions in other organs. The lung tumors were adenomas and the mean number of adenomas was 2.2-2.6 per mouse. Phenobarbital combination had no additive effect on lung tumor incidence and multiplicity. Splenic NK cell activity showed inconsistent increment in the carcinogen plus phenobarbital-treated group during the experiment (P less than 0.05).     

The effectiveness of cis-platinum,cyclophosphamide and melphalan in treating disseminated tumor cells in mice

Both B16 melanoma and Lewis lung carcinoma growing in C57/B1 mice spontaneously metastasize to the lungs and other organs. When the tumors are grown in the mouse tail to a specific volume and amputated, the spontaneously disseminated tumor cells can then be independently treated. The effects of a single dose of cyclophosphamide (200 mg/kg), cis-platinum (6 mg/kg) and melphalan (10 mg/kg) on the appearance of pulmonary and other metastases were measured. The cis-platinum treatment was shown to reduce the number and incidence of metastases of both tumors at various times after treatment. The antimetastatic effectiveness of cis-platinum against these two tumors was increased when 2·4 mg/kg was administered each day for five consecutive days after amputation of the primary. Cyclophosphamide, when administered at two-thirds maximum tolerated dose, had a small promoting effect on the number and incidence of pulmonary metastases of Lewis lung carcinoma, whereas, applied in the same dose, it had efficacy in the treatment of disseminated B 16 melanoma and inhibited appearance of both pulmonary and lymph-node metastases. When melphalan was administered in single- and multiple-dose regimens, the number and incidence of metastases of both tumors increased at various times after primary tumor amputation. These data suggest that melphalan can promote the growth of disseminated tumor cells in both the lungs and other sites and that some systemic chemotherapies may result in promotion instead of suppresssion of metastatic disease     

Caloric restriction perturbs the pituitary-ovarian axis and inhibits mouse mammary tumor virus production in a high-spontaneous-mammary-tumor-incidence mouse strain (C3H/SHN)

Dietary restriction (DR) retards aging and extends maximum life span. It is also known to decrease the incidence of hormone-dependent tumors. In the present investigation, we focussed primarily on the influence of DR on the pituitary-ovarian axis, and subsequently on gene expression of the mouse mammary tumor virus. F1 females from the mating of SHN female and C3H male mice were used in this study, since these hybrids display a very high incidence of mouse mammary tumors. The mice weaned at 3 weeks were raised on either a calorically-restricted diet (DR: 50 kcal/week; N = 5) or on a control diet (C: 95 kcal/week N = 5) for 5 weeks. Three C57BL/6J Jcl ad libitum-fed female mice, 8 weeks of age, were used as reference animals since this strain has a very low incidence of mammary tumors. The mean cellular contents of prolactin (PRL) and growth hormone (GH) in the pituitary, as determined by immunohistochemistry, were found to be reduced in mice raised on the DR diet. The decrease in the mean cellular content of PRL (50% of the mean control value) was accompanied by a decrease in the number of lactotrophs (17% of the mean value of control diet mice). However, the decrease in cellular content of GH (53% of the mean control value) was not accompanied by a decrease in the number of somatotrophs (no. of somatotrophs in DR = 103% of mean control value). Histologically, ovaries from DR mice showed many growing and atretic follicles, with few corpora lutea. In contrast, both control-diet and reference (C57BL/6J Jcl) mice showed two or three corpora lutea per ovarian section. In accordance with this finding, DR mice had not established stable estrus cycles by 8 weeks of age, in contrast to both control-diet and reference mice. Since caloric restriction has been shown to decrease mammary tumor virus (MMTV) gene expression, MMTV production was investigated by electron microscopy to confirm the validity of our experimental conditions. In DR or reference C57BL/6J Jcl mice, MMTV particles were rarely found in the mammary gland samples, but were always found in samples from control mice. The development of mammary glands, as indicated by the number of villi or the development of the rough endoplasmic reticulum, was delayed in DR mice. Thus, it was concluded that caloric restriction decreases the number of lactrotrophs, inhibits ovulation and delays mammary gland development. This immature status is considered to be due to perturbations in the pituitary-ovarian axis by caloric restriction.     

Experimental postoperative adjuvant chemotherapy by UFT using primary tumor amputation model

We evaluated the postoperative adjuvant chemotherapy by UFT using the primary tumor amputation-pulmonary metastasis model. When Lewis lung carcinoma (LLC) primary tumors on the hind foot pad grew palpable, they were amputated on two different days. In experiment (A) (earlier amputation model), micrometastases were detected on the day of amputation only by the histopathological examination. In the experiment (B) (later amputation model), nodules could be determined even by necropsy. Long-term (60-day) consecutive administration of UFT (22 mg/kg/day), which produced no body weight loss, markedly prolonged the survival period in experiment (A) (ILS: over 118%), 1 of the 15 mice being cured. UFT had a relatively weak but significant effect (67% of ILS) in schedule (B). Using the same model, we examined the inhibitory effect of UFT (2-week administration) on the number of metastatic nodules. A significant decrease of metastatic nodules was observed by UFT with both amputation schedules, but its effect was superior with schedule (A). In the same model using Colon 26 PMF-15, UFT markedly prolonged the survival period of mice (150% of ILS) and significantly decreased the metastatic nodules (86% inhibition). The dose of UFT used was relatively low, and did not significantly inhibit the growth of large tumors. However, the sensitivity to the micrometastases was high. These findings suggest that the postoperative adjuvant chemotherapy by the long-term consecutive administration of UFT would be effective for clinical cancer especially in curatively resected cases.     

Keratin expression in chemically induced mouse lung adenomas.

Chemically induced mouse lung tumors exhibit distinctive growth patterns, characterized by an alveolar or solid appearance, a papillary appearance, or a combination of the two. Lung tumors induced in strain A/J mice by either benzo(a)pyrene (BP) or by N-nitrosoethylurea (ENU) were examined for expression of low- and high-molecular-weight cytokeratins. Simple cytokeratins (low molecular weight) were found in all epithelial cells of the normal mouse lung and in all tumor types, whereas higher-molecular-weight cytokeratins were found only in normal bronchiolar cells and in papillary tumor cells. These data lend support to the hypothesis that chemically induced papillary lung tumors in strain A/J mice are derived from bronchiolar Clara cells.     

Immunotoxicologic effects of cyclosporine on tumor progression in models of squamous cell carcinoma and B-cell lymphoma in C3H mice

Many immunosuppressive drugs are associated with an increased risk of neoplasia, principally non-melanoma skin cancers and B-cell lymphomas. However, only 6 of the 13 immunosuppressive drugs tested in 2 year bioassays increased the incidence of neoplasia. For example, the 2-year bioassays conducted with cyclosporine (CSA), an International Agency for Research on Cancer (IARC) Group 1 human carcinogen, were negative. The purpose of these investigations was to use transplanted tumor models in immunocompetent, syngeneic mice to gain insight into the failure of the 2-year bioassay to show an increased incidence of neoplasia with CSA. C3H HeN mice were used in a battery of assays with a transplanted squamous cell carcinoma (SCC VII cells) or a B-cell, lymphoma (38C13 cells) cells to study effects of CSA on local growth and metastases, experimental metastases, and progression of established metastases. Mice received CSA twice weekly by subcutaneous (SC) injection at doses of 0.5, 5, or 50 mg/kg; controls received the CSA vehicle. CSA had a modest inhibitory effect on SC tumors initiated by 38C13 cells and on intramuscular tumors initiated by SCC VII cells. CSA also decreased the number of lung colonies and decreased the size, growth fraction and vascularity of established lung metastases initiated by SCC VII cells. In contrast, CSA increased progressive growth of metastases to the sentinel lymph node from an intramuscular SCC VII tumor, but had no effect cellular traffic to the node. In conclusion, CSA at doses up to 50 mg/kg did not facilitate tumor progression and it partially inhibited tumor growth, suggesting that suppression of tumor progression may partially explain the failure of CSA to act as a carcinogen in 2 year bioassays.     

Immunotoxicologic effects of cyclosporine on tumor progression in models of squamous cell carcinoma and B-cell lymphoma in C3H mice

Many immunosuppressive drugs are associated with an increased risk of neoplasia, principally non-melanoma skin cancers and B-cell lymphomas. However, only 6 of the 13 immunosuppressive drugs tested in 2 year bioassays increased the incidence of neoplasia. For example, the 2-year bioassays conducted with cyclosporine (CSA), an International Agency for Research on Cancer (IARC) Group 1 human carcinogen, were negative. The purpose of these investigations was to use transplanted tumor models in immunocompetent, syngeneic mice to gain insight into the failure of the 2-year bioassay to show an increased incidence of neoplasia with CSA. C3H HeN mice were used in a battery of assays with a transplanted squamous cell carcinoma (SCC VII cells) or a B-cell, lymphoma (38C13 cells) cells to study effects of CSA on local growth and metastases, experimental metastases, and progression of established metastases. Mice received CSA twice weekly by subcutaneous (SC) injection at doses of 0.5, 5, or 50?mg/kg; controls received the CSA vehicle. CSA had a modest inhibitory effect on SC tumors initiated by 38C13 cells and on intramuscular tumors initiated by SCC VII cells. CSA also decreased the number of lung colonies and decreased the size, growth fraction and vascularity of established lung metastases initiated by SCC VII cells. In contrast, CSA increased progressive growth of metastases to the sentinel lymph node from an intramuscular SCC VII tumor, but had no effect cellular traffic to the node. In conclusion, CSA at doses up to 50?mg/kg did not facilitate tumor progression and it partially inhibited tumor growth, suggesting that suppression of tumor progression may partially explain the failure of CSA to act as a carcinogen in 2 year bioassays.     

Effect of all-trans retinoic acid (ATRA) on syndecan-1 expression and its chemoprotective effect in benzo(α)pyrene-induced lung cancer mice model

All-trans retinoic acid (ATRA), an active metabolite of retinal, has been shown to exert anti-cancer activities in a number of cancer cells and tissues. Syndecan-1 is a proteoglycan, mediate cell–cell adhesion and prevent invasion in epithelial cells. The aim of the present study was to examine the level of syndecan-1 expression and the chemopreventive effect of ATRA during lung cancer development in BALB/c mice. Syndecan-1 expression was examined by immunohistochemistry using mouse monoclonal anti-human syndecan-1 antibody. In this study, benzo(α)pyrene [B(α)P] was used to induce lung cancer. The results indicated that ATRA has anti-cancer effect against B(α)P-induced lung tumor development as induced by number of tumor nodules and histopathologic report. The loss of syndecan-1 expression in the epithelial cell membrane is associated with tumor cell growth and invasiveness. Our study for syndecan-1 indicated a chemoprotective effect of ATRA against changes in lung epithelial cell membrane syndecan-1 expression in B(α)P-induced lung cancer model. Therefore ATRA could serve as effective chemotherapeutic agent against cancer invasion/metastasis, at least in the lungs.     

Effects of sodium fusidate in animal models of insulin-dependent diabetes mellitus and septic shock.

We have evaluated the effects of the novel immunosuppressant sodium fusidate (fusidin) in the non-obese diabetic (NOD) mouse and in D-galactosamine (D-Gal)-presensitized BALB/c mice challenged with the bacterial superantigen, Staphylococcus aureus enterotoxin B (SEB) or with the endotoxin, Escherichia coli lipopolysaccharide (LPS). The NOD mouse model has clinical and histoimmunological features similar to those of human insulin-dependent diabetes mellitus (IDDM). The SEB- and LPS-treated BALB/c mouse models exhibit pathogenic similarities with human septic shock conditions. In the NOD mouse, fusidin suppressed the spontaneous development of insulitis (mean inhibition 73%) and hyperglycaemia (IDDM incidence 25% versus 0%) when administered at 40 mg/kg five times weekly for 8 consecutive weeks from the fourth week of age; concurrently treated animals exhibited reduced percentages of splenic T lymphocytes. This anti-diabetogenic effect was confirmed in the accelerated model of diabetes induced in the NOD mouse with cyclophosphamide (CY) (IDDM incidence 55% versus 21-6% using dosages of fusidin from 40 to 80 mg/kg five times weekly); protection from IDDM development was achieved even when the drug (80 mg/kg/day) was first administered 7 days after CY challenge. In contrast, fusidin did not reverse hyperglycaemia when administered to CY-treated animals within 3 days of IDDM development. In the two models of septic shock, prophylactic treatment with fusidin, 80 mg/kg given three times for 2 days prior to D-Gal/SEB or D-Gal/LPS challenge, drastically reduced the lethality compared with D-Gal/buffer-treated mice. This effect may depend on the inhibitory action of fusidin on the secretion of cytokines such as interferon-gamma and tumour necrosis factor-alpha, the serum levels of which were greatly diminished in the fusidin-treated mice (mean inhibition 50-90%). These results demonstrate that fusidin may have a role in the treatment of cell-mediated autoimmune diseases and cytokine-mediated infectious diseases in humans.     

Transplacental induction of mouse lung tumors: stage of fetal organogenesis in relation to frequency, morphology, size, and neoplastic progression of N-nitrosoethylurea-induced tumors

Pregnant C3H/HeNCr MTV- mice were given a single intraperitoneal injection of 0.5 mmol N-nitrosoethylurea/kg on days 14, 16, or 18 of gestation. Six of the male offspring were sacrificed for study at the ages of 2, 4, 8, 16, 32, and 52 weeks. Grossly visible lung tumors were counted and all lungs were sectioned completely, saving every tenth section for histologic evaluation. All N-nitrosoethylurea-induced mouse lung tumors have previously been shown to originate from alveolar type II cells. Lung tumors were diagnosed as solid, papillary, or mixed solid/papillary types, and at the largest area of each tumor, the perimeter was measured and compared with the number of sections per tumor. The fraction of tumors detected grossly depended on size and, on average, only 51% of neoplasms present were detected macroscopically. A significant correlation was seen between the mean number of histological sections and perimeter length per tumor, in particular for small and medium sized papillary neoplasms. The growth of solid tumors was limited to a maximum size, after which they progressed towards papillary types. The numbers of transplacentally induced mouse lung tumors were distributed in direct proportion to the weight of the individual lung lobes, unrelated to day of treatment of type or tumor. Tumor biology depended on the day of treatment reflecting numbers of degree of differentiation of fetal alveolar type II cells, i.e., the target cell: most tumors developed in offspring treated on day 16, tumor size was greater and progression from solid to papillary neoplasms faster at earlier treatments, increase in tumor multiplicity postnatally was only seen in mice treated late in gestation, and mice treated on day 14 or day 16 showed a consistent ratio of solid to papillary tumors.     

Strain A/J mouse lung adenoma growth patterns vary when induced by different carcinogens.

The histogenesis of mouse lung adenomas is currently being investigated in several laboratories. Based upon studies of a limited number of carcinogens in different mouse strains, some investigators suggest that all lung adenomas in mice are derived from alveolar type II cells, whereas others suggest a Clara cell origin for a majority of the tumors. This report differs from previous investigations in that 12 different carcinogens were evaluated for the types of lung tumor growth patterns they induced in a single mouse strain (strain A mice). The carcinogens aflatoxin B1 (AFB1), benzo(a)pyrene (BP), 1,2-dimethylhydrazine (DMH), 3-methylcholanthrene (MCA), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), and N-nitrosomethylurea (MNU) induced tumors with a predominantly solid/alveolar growth pattern, whereas N-nitrosodiethylamine (NDEA) induced predominantly papillary tumors. Most of the other carcinogens induced a higher proportion of lung tumors with the solid/alveolar growth pattern than with the papillary growth pattern; however, ratios between the 2 growth patterns varied. If, as suggested by others, solid tumors are derived from alveolar type II cells and papillary tumors from Clara cells, then carcinogens may differ with respect to their ability to transform one cell type or the other.     

黄芪多糖联合顺铂对小鼠Lewis肺癌细胞肺转移的影响

目的观察黄芪多糖(APS)联合顺铂(DDP)对小鼠Lewis肺癌细胞肺转移、核因子(NF)-κB、P38、P53及Caspase-9表达的影响。方法将90只Lewis小鼠随机分为模型组、顺铂组(6mg/kg DDP)、APS组(50、100、200)mg/kg,联合用药组[1/2 DDP+APS,即:(3+25、3+50、3+100)mg/kg]。各组均于造模第2天起用药,APS每日1次,DDP每周1次,连续20d。观察肿瘤肺转移情况,采用Real-time PCR法和Western blotting法检测肿瘤组织中NF-κB、P38、P65蛋白和基因,并用免疫组织化学检测Caspase-9的表达。结果与模型组相比,各治疗组均可降低肺转移灶数目(P0.05或P0.01);除P38外,APS中、高剂量组可使小鼠Lewis肺癌组织中NF-κB p65、P53表达降低,Caspase-9表达增高;联合用药高剂量组作用则接近DDP组。结论 APS可抑制小鼠Lewis肺癌细胞的转移,抑制NF-κB和丝裂原活化蛋白激酶(MAPK)信号通路的激活,这可能是其抑制肿瘤转移的机制之一;APS与减半剂量的DDP铂类化疗药物联合使用时,作用增强,APS对DDP有增效减毒作用。     

The Effect of Different Doses of Cigarette Smoke in a Mouse Lung Tumor Model

Few studies have used Balb/c mice as an animal model for lung carcinogenesis. In this study, we investigated the effect of different doses of cigarette smoking in the urethane-induced Balb/c mouse lung cancer model. After injection of 3mg/kg urethane intraperitoneally, the mice were then exposed to tobacco smoke once or twice a day, five times a week, in a closed chamber. The animals were randomly divided into four groups. The control group (G0) received urethane only. The experimental groups (G1, G2 and G3) received urethane and exposure to the smoke of 3 cigarettes for 10 minutes once a day, 3 cigarettes for 10 minutes twice a day, and 6 cigarettes for 10 minutes twice a day, respectively. The mice were sacrificed after 16 weeks of exposure, and the number of nodules and hyperplasia in the lungs was counted. The results showed no statistically significant difference in the mean number of nodules and hyperplasia among the different groups, suggesting that the Balb/c mice are not suitable to study the pathogenesis of tobacco smoking-induced tumor progression in the lungs.     

31P NMR spectroscopic study of bioenergetic changes in radiation-induced fibrosarcoma-1 after radiation therapy

The effects of localized gamma-irradiation on the in vivo 31P NMR spectra of RIF-1 tumors grown subcutaneously in C3H/HeN mice have been examined before and during the week after treatment. Increases in the ratio of phosphocreatine (PCr) to inorganic phosphate (Pi) and in tumor pH, and decreases in the ratio of Pi to the beta phosphorus resonance of the nucleotide triphosphates (beta NTP) were observed in irradiated tumors. The time course of changes in the 31P spectrum following treatment was the opposite of the pattern during untreated growth, and the magnitude and duration of the changes increased with increasing radiation dose, decreasing clonogenic cell survival and increasing growth delay. To examine the possibility that nontherapeutic systemic effects of the tumor irradiation were responsible for the changes observed, a number of animals bearing two tumors were examined. One tumor on each mouse was selectively irradiated. Changes in tumor volume, Pi/beta NTP, PCr/Pi, the ratio of phosphomonoesters to beta NTP, and tumor pH were all significantly different in the treated compared to the untreated tumor on each animal, indicating that these changes in 31P NMR spectra were a response to radiation therapy and not a systemic response to radiation toxicity.     

RETROVIRUS PARTICLES IN SPONTANEOUSLY OCCURRING AND RADIATION-INDUCED TUMORS IN ddY MICE

Among spontaneously occurring tumors, pulmonary tumor, malignant lymphoma, mammary tumor, and ovarian tumor were the major ones in 232 ddY female mice. The former three tumors appeared significantly earlier and the latter one increased in incidence in 229 mice given 600 R whole or 800 R partial body (tunk) x-irradiation at the age of 10 weeks. Five tumors were examined electronmicroscopically from each tumor type of both the spontaneously occurring and radiation-induced tumors. G type virus particles were present only in the malignant lymphoma and B particles in the mammary, ovarian and pulmonary tumors, which are all of epithelial character. Thus, as far as we were concerned in this mouse strain, B particles were produced preferentially in epithelial cells and C particles in non-epithelial cells. The retrovirus particles were found in the same frequency, namely, 10 of 20 tumors examined in both the tumor groups. From our results, the intervention of virus in radiation carcinogenesis still remains in question.     

重组人血管内皮抑制素抗肿瘤效应的应用研究

目的探讨基因工程人血管内皮抑制素(endostatin)抑制黑素瘤在小鼠体内生长和转移的作用及其作用机制。方法接种黑素瘤细胞悬液(2×10     

雌激素在煤焦沥青烟致小鼠肺癌模型建立 过程中的作用研究

目的 建立以煤焦沥青（CTP）烟提取物灌胃诱发雌性KM小鼠肺癌的动物模型,并以雌二醇（E2）为代表,研究雌激素在该CTP致小鼠肺癌模型过程中的作用。方法 将260只5周龄清洁级雌性KM小鼠按随机原则分为9组,分别为CTP组（27只）、CTP+E2组（28只）、CTP+TAM组（29只）、CTP+E2+TAM组（28只）、E2组（34只）、TAM组（30只）、E2+TAM组（29只）、溶剂对照组（27只）、空白对照组（28只）,每组分别给予不同的染毒处理,观察并记录小鼠的生长、活动、饮食和健康状况,并称量体重。染毒后10周处死,收集各组肺组织,HE染色后,显微镜观察组织病理变化情况;观察肿瘤发生数,计算肺癌发生率。结果 CTP+E2+TAM组小鼠肺癌发病率为32.14%,其肺癌发病率和肿瘤数均低于CTP+E2组,差异无统计学意义（P＞0.05）;CTP组小鼠肺癌发病率为26.92%,其肺癌发病率和肿瘤数均高于溶剂对照组和空白对照组（P＜0.05）;CTP+E2组的肺癌发病率最高,为57.14%,其肺癌发病率和肿瘤数均高于对照组和单纯E2组（P＜0.05）;肿瘤结节HE染色确诊的肿瘤均为腺瘤,与正常肺组织分界清楚。肿瘤组织呈腺样排列,主要位于核膜下。结论 建立了CTP烟提取物诱发雌性KM小鼠肺癌的动物模型,E2能够促进CTP烟提取物诱发的小鼠肺癌。     

Protective effects of salidroside from Rhodiola rosea on LPS-induced acute lung injury in mice

Salidroside is a major component extracted from Rhodiola rosea. In this study, we investigated protective effects of salidroside on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. In the mouse model, we found that pretreatment with a single 120?mg/kg dose of salidroside prior to the administration of intratracheal LPS induced a significant decrease in the W/D ratio and mouse myeloperoxidase activity of lung, reduction protein concentration, the number of total cells, neutrophils and macrophages in the bronchoalveolar lavage fluid. In addition, salidroside also inhibited the production of several inflammatory cytokines, including tumor necrosis factor-α, interleukin-6 (IL-6) and IL-1β, and the NF-κB DNA-binding activation after LPS challenge. These results indicated that salidroside possess a protective effect on LPS-induced ALI in mice.     

Effect of matrix metalloproteinase inhibitors on tumor growth and spontaneous metastasis

Four potent, synthetic inhibitors of matrix metalloproteinases (MMPs) were assessed as inhibitors of tumor growth and spontaneous metastasis to the lung. Mat Ly Lu rat prostate tumor, LOX human melanoma and M27 murine Lewis lung tumor were implanted subcutaneously (s.c.) in mice and allowed to grow for 3–12 days. The lungs of the tumor-bearing mice were then removed and implanted s.c. into untreated mice, and the outgrowth of secondary tumors from the implanted lungs measured. The incidence and rate of outgrowth of secondary tumors increased with the length of primary tumor growth, validating these measurements as indices of spontaneous metastasis to the lung. Compounds were tested by sc. implantation of minipumps which delivered compound throughout the period of primary tumor growth and spontaneous metastasis to the lung at steady-state drug concentrations orders of magnitude greater than the concentrations needed to either inhibit collagenase, gelatinase or stromelysin in vitro. Inhibitor treatment slowed the growth of primary s.c. Mat Ly Lu and LOX tumors by 40–60% but had no significant effect on the growth of primary M27 tumors. Surprisingly, inhibitor treatment had no significant effect on the ability of the lung to generate secondary tumors when reimplanted s.c. in untreated mice. Because of the possible importance of cathepsins B, H and L in tumor growth and metastasis, the irreversible inhibitor E-64 was also infused by s.c. minipump. E-64 had no effect on the growth or spontanous metastasis of Mat Ly Lu or M27 tumors.     

Src Tyrosine Kinase Inhibitor,M475271, Suppresses Subcutaneous Growth and Production of Lung Metastasis Via Inhibition of Proliferation,Invasion, and Vascularization of Human Lung Adenocarcinoma Cells

Src, a proto-oncogene, has been strongly implicated in the growth, progression and metastasis of a number of human cancers. Its role in lung cancer is, however, still unknown. In the present study, we assessed the expression of Src in three different human lung adenocarcinoma cell lines (PC-9, PC14PE6, A549), and explored the effect of a novel Src kinase inhibitor, M475271, on the behavior of the cell lines. The three cell lines expressed various levels of auto-phosphorylated Src. While M475271 reduced Src-phosphorylation and invasiveness of all three cell lines, it inhibited the proliferation of PC-9 and A549 cells with highly phosphorylated Src, but not PC14PE6 cells. We further examined the effect of M475271 on subcutaneous tumors and lung metastasis caused by PC-9 and/or A549 cells in NK-cell depleted SCID mice. Daily oral treatment with M475271 inhibited the growth of subcutaneous tumors with PC-9 and A549 cells via inhibition of tumor cells proliferation, VEGF production and/or vascularization in the mice in a dose-dependent manner. In the metastasis model with A549 cells, the lung weight in the M475271 (50 mg/kg)-treated group was less than that of the control group, despite no difference in the number of metastatic nodules. Our results suggest that inhibition of tyrosine kinase Src by M475271 could reduce the growth, invasion and VEGF-mediated neovascularization of lung adenocarcinoma cells, resulting in inhibition of growth of subcutaneous tumors and lung metastasis. Therefore, a novel Src tyrosine kinase inhibitor, M475271, might be helpful for controlling the progression of human lung adenocarcinoma.