Minimal liver resection strongly stimulates the growth of human colon cancer in the liver of nude mice

Partial hepatectomy has been widely employed in clinical practice as the therapy of choice for primary and metastatic liver tumors. However, the recurrence rate after the treatment remains high, which is most likely due to the growth of residual microscopic lesions. Previous studies in murine models demonstrated that a 70% hepatectomy significantly accelerated the growth of ectopically implanted tumors. In this study, we reported the effect of partial hepatectomy on the growth of two human colon cancers (Co-3 and AC3603) implanted in the liver of nude mice using the technique of surgical implantation of histologically intact tumor tissue. Our results showed a dramatic acceleration of tumor growth following 30% partial hepatectomy, which resembles clinical procedures. Tumor volumes were assessed with calipers on day-15 by abdominal palpation and on day-30 at autopsy by direct measurement. For both Co-3 and AC3603, tumor volumes in the hepatectomized animals were significantly larger than the control at the above two time points (P<0.001). The results demonstrate the stimulating effect of partial hepatectomy directly on the tumor growth in the liver, in contrast to previous studies on ectopic tumors. Furthermore, since conservative partial hepatectomy (30%) is normally used in clinical practice for surgical treatment of liver metastasis, the animal models presented here should be useful for the clinical investigation of the high recurrence rate of liver metastasis following partial hepatectomy. This revised version was published online in July 2006 with corrections to the Cover Date.     

Reproduction of occult metastasis of head and neck cancer in nude mice

The presence of occult metastasis is the most important factor that influences the prognosis in patients with head and neck cancer. To reproduce occult metastasis of oral cancer cells, we serially resected the primary focus in an orthotopic implantation model to examine when metastasis of cancer cells occurs. Human squamous cell carcinoma was implanted into the tongue of nude mice divided into two groups, non-surgery and surgery groups. Mice in the non-surgery group were sacrificed, and the tongue cancer and cervical lymph nodes were resected simultaneously. In the surgery-group, resection of the tongue cancer was performed, and the cervical lymph nodes were resected on day 28. For the non-surgery-group, the incidences of metastasis were 0%, 9%, 36%, 91% and 100% on days 3, 7, 14, 21 and 28, respectively. For the surgery-group, resection of the tongue cancer was performed on days 3, 7 and 14, and the incidence of metastasis on day 28 was 0%, 82% and 91%, respectively. The occult metastasis was reproduced using resected primary cancer on day 7. This time-based model may be useful to clarify the mechanism of metastasis and to develop new treatments.     

Metastatic patterns of lung cancer visualized live and in process by green fluorescence protein expression

We demonstrate here the visualization of human lung cancer metastasis live and in process in nude mice by green fluorescent protein (GFP) expression. The human lung adenocarcinoma cell line Anip 973 stably transfected with the humanized GFP-S65T cDNA was selected for very bright green fluorescence. GFP-transfected lung cancer cells were initially inoculated subcutaneously in nude mice. Five weeks after transplantation, the resulting tumor had reached over 1 cm in diameter and had very bright GFP fluorescence. Fragments of subcutaneous tumor were implanted onto the visceral pleura of the left lung of nude mice by surgical orthotopic implantation (SOI) of histologically-intact tissue via transverse thoracotomy. The ipsilateral resulting tumor was highly fluorescent due to GFP expression. GFP expression allowed the visualization of the advancing margin of the ipsilateral tumor into the fresh normal lung tissue. Lymphogenous and direct-seeding metastases in the pulmonary hilum, cervical lymph nodes, the mediastinum and contralateral pleural cavity and contralateral lung in the SOI-treated mice were brightly visualized by GFP expression in fresh tissue. GFP-transfected and untransfected tumor had similar metastatic characteristics suggesting that GFP expression had no effect on metastasis itself. The results with the GFP-transfected tumor cells, combined with the use of SOI, demonstrate a fundamental advance in the visualization and study of lung cancer metastasis in process.     

A patient-like orthotopic implantation nude mouse model of highly metastatic human ovarian cancer

Clinically relevant animal models of human cancer are important for studies of cancer biology, invasion and metastasis, and for investigating new forms of prognostic diagnosis and therapy. An ovarian tumor line (RMG-1: human clear cell carcinoma of the ovary) previously grown subcutaneously was implanted ortho-topically as intact tissue into the ovarian capsule of 22 nude mice. The tumors showed progressive growth at the orthotopic site in all animals. Tumor-associated serum galactosyltransferase (GAT) tended to be posi-tive in all nude -mice. The tumors invaded or metastasized to the contralateral ovary, retroperitoneum, mesentery and peritoneum, and omentum, and metastasized to the subcutaneous tissue, lymph nodes and distant organs including the liver, kidney, pancreas, and diaphragm. In striking contrast, subcutaneous trans-plantation of this tumor resulted in growth in only 2 of 5 animals with local lymph node and kidney involve-ment but no retroperitoneal or peritoneal involvement. These findings suggest that orthotopic implantation provides a suitable micro-environment in which ovarian cancer can express its intrinsic clinically-relevant properties. This approach is relevant to the clinical features of ovarian cancer and is thought to be a useful model for studies of therapy for this cancer.© Kluwer Academic Publishers 1998     

Peritoneal metastatic model for human scirrhous gastric carcinoma in nude mice

We established a peritoneal-metastatic model for scirrhous gastric carcinoma. Peritoneal metastasis had developed after intraperitoneal inoculation of OCUM-2MD3 cells in nude mice. This cell line was derived from a peritoneal-metastatic nodule at the mesenterium after orthotopic implantation of OCUM-2M cells which developed no peritoneal metastasis after intraperitoneal inoculation. The histologic findings of orthotopic-implanted tumor in the stomach show scirrhous type while those of subcutaneous-implanted tumor show medullary type. There might be factors, in OCUM-2MD3 cells, which are responsible for peritoneal metastasis. We next investigated the differences in the biological behavior of the original OCUM-2M and the derived variant OCUM-2MD3. Morphology and growth activity of the two cell lines were similar to each other. The specific chromosomes, add(6)(g13), del(7)(q21.2) and inv(11)(pl3q21), were found in OCUM-2MD3 cells but not in OCUM-2M cells. While the oncogenes amplification by OCUM-2M cells was found in K-sam and c-myc, that by OCUM-2MD3 cells was found only in c-myc. The expression of E-cadherin by OCUM-2MD3 cells was decreased compared with that of OCUM-2M cells. Expression level of β1-integrin of OCUM-2MD3 cells was higher than that of OCUM-2M cells. The binding and invasion activity of OCUM-2MD3 cells were higher than those of OCUM-2M cells, and were decreased by anti-β1-integrin antibody. The invasion activity of OCUM-2MD3 cells was increased in the presence of peritoneal fibroblast. In this study, it was suggested that orthotopic implantation of cancer cells might have an effect on the acquisition of metastatic ability. β1-integrin and peritoneal fibroblasts might be correlated with peritoneal metastasis. This peritoneal-metastatic model should be useful for analysing the mechanism of peritoneal metastasis of human scirrhous gastric cancer.     

裸鼠皮下人肝癌移植瘤模型的建立

目的建立裸鼠皮下肝癌移植瘤模型。方法BLBA/c裸鼠颈背部皮下注射人肝癌SMMC-7721细胞悬液5×106个.0.2m l-1.只-1,观察肿瘤生长情况,45d处死。瘤组织作病理及电镜检查;取裸鼠周围血作甲胎蛋白(AFP)的检测;用免疫组化法检测肿瘤微血管密度(MVD)。结果该模型具有类似人原发性肝癌的形态学特征。结论成功建立了人肝癌裸鼠皮下移植瘤模型。     

Antimetastatic efficacy of adjuvant gemcitabine in a pancreatic cancer orthotopic model

Gemcitabine is a promising new agent that has been recently studied for palliation of advanced (stage IV) unresectable pancreatic cancer. We hypothesized that adjuvant gemcitabine would reduce recurrence and metastases following surgical resection of pancreatic cancer. To test this hypothesis, we evaluated gemcitabine on a green fluorescent protein (GFP) transductant of the human pancreatic cancer cell line BxPC-3 (BxPC-3-GFP) using surgical orthotopic implantation (SOI) in nude mice. GFP enabled high resolution fluorescent visualization of primary and metastatic growth. Five weeks after SOI, the mice were randomized into three groups: Group I received exploratory laparotomy only. Group II underwent surgical resection of the pancreatic tumor without further treatment. Group III underwent tumor resection followed by adjuvant treatment with gemcitabine, 100 mg/kg every three days for a total of four doses, starting two days after resection. The mice were sacrificed at thirteen weeks following implantation and the presence and location of recurrent tumor was recorded. Gemcitabine reduced the recurrence rate to 28.6% compared to 70.6% with resection only (P=0.02) and reduced metastatic events 58% in the adjuvant group compared to resection only. This study, demonstrating that gemcitabine is effective as adjuvant chemotherapy post-pancreatectomy, suggests this new indication of the drug clinically. This revised version was published online in July 2006 with corrections to the Cover Date.     

Establishment of lymph node metastatic model for human gastric cancer in nude mice and analysis of factors associated with metastasis

The actual mechanisms responsible for lymph node metastasis in gastric cancer are still unclear. To investigate the mechanisms of lymph node metastasis in gastric cancer, we established a lymph node metastatic model for human scirrhous gastric carcinoma. Lymph node metastasis had frequently developed after orthotopic implantation of OCUM-2M LN derived from a scirrhous gastric cancer cell line, OCUM-2M, which had low capacity for lymph node metastasis. We elucidated the different characteristics including binding ability, migratory capacity and immunoresponses induced by the cell surface molecules of these two cell lines. The binding ability to Matrigel and migratory capacity of OCUM-2M LN cells were significantly greater than those of OCUM-2M cells. On flow cytometric analysis, both OCUM-2M and OCUM-2M LN cells strongly expressed HLA-I (99.5 and 97.1%) and LFA-3 (76.6 and 99.2%) in level of expression between the two cell lines, but neither cell line expressed HLA-II (0.0 and 0 .0%), B7-1 (0.0 and 0.0%) or B7-2 (0.4 and 0.3%). ICAM-1 expression in OCUM-2M LN cells was weaker (0.7%) than that in OCUM-2M cells (36.8%). Strong adhesiveness and cytotoxicity of mononuclear lymphocytes for OCUM-2M cells were observed in adhesion and cytotoxic assays, both of which were significantly decreased by the addition of anti-ICAM-1 antibodies. On the other hand, the adhesiveness and cytotoxicity of OCUM-2M LN cells were significantly less than those of OCUM-2M cells, and were not affected by the addition of anti-ICAM-1 antibodies. These findings suggest that decreased ICAM-1 expression in a new gastric cancer cell line with a high rate of lymph node metasta-sis may in turn decrease immune responses mediated through LFA-1-dependent effector cell adhesion, and that this escape from the immunosurveillance system may be one of the factors inducing lymph node metas-tasis. In conclusion, we established a gastric cancer cell line, OCUM-2M LN, with a high rate of lymph node metasta sis. An in vivo lymph node-metastatic model with this cell line should be useful for analysing the mech-anism and therapeutic approach of lymph node metastasis. © Rapid Science Ltd.     

采用HepG2细胞株建立裸鼠肝癌模型的方法

目的 :探讨采用HepG2 细胞株建立裸鼠肝癌模型的方法。方法 :采用皮下注射HepG2 细胞 (1 2× 1 0 6)建立裸鼠肝癌模型 ,观察种植细胞后 1 4天内裸鼠的死亡率 ,并在 1 4天时活杀动物测定瘤体重量、直径及血清AFP浓度。结果 :该法造模成功率达 1 0 0 %。结论 :该方法操作简便 ,周期短 ,成功率高等可作为肝癌模型应用     

Magnetic resonance imaging for the evaluation of a novel metastatic orthotopic model of human neuroblastoma in immunodeficient mice

Neuroblastoma is the second most common solid tumor in children. So far few tumor models for this cancer have been reported in mice. We have created a murine tumor model for studying human neuroblastoma based on surgical orthotopic implantation in scid mice. Small fragments of subcutaneous tumors of SK-N-BE(2) human neuroblastoma cells expressing enhanced green fluorescent protein were surgically implanted near the left adrenal gland of scid mice. One hundred percent of the animals (n=21) successfully implanted developed a large retroperitoneal tumor and became moribund between 22 and 57 days after implantation (mean survival time = 41 days). At the time of sacrifice the presence of bone marrow metastasis was detected by RT-PCR for green fluorescent protein in 95% of the cases. The growth of small tumor implants could be easily visualized and quantified by surveillance MR imaging, with a resolution of 117×117×750 μm in two orthogonal planes allowing accurate volume measurements, as well as assessment of necrosis and tissue invasion. This novel model should be a valuable tool to study the biology and therapeutic approaches to neuroblastoma. This revised version was published online in July 2006 with corrections to the Cover Date.     

裸鼠人肝癌模型模拟临床化疗实验研究

目的 探讨人肝癌组织裸鼠原位种植模型体内筛选供瘤病人敏感的化疗药物可行性。方法 荷瘤鼠随机分为对照组和表阿霉素（E—ADM）、5氟脲嘧啶（5-FU）、丝裂霉素（MMC）四组。腹腔化疗每周1次，共4次。B超观测移植瘤大小，化疗结束1wk后处死荷瘤鼠．分别用免疫组化（SP）、RT—PCR、Western blot方法检测移植瘤MDR1和LRP蛋白及其mRNA表达情况。选择敏感和低致多药耐药的化疗药物用于供瘤病人。结果 3个化疗组肿瘤体积均逐渐缩小，与对照组相比差异均有显著性（P〈0．05）。各检测方法均示E—ADM组MDR1和LRP蛋白及其mRNA表达升高，差异有显著性（P〈0．05）。5-Fu组LRP表达升高，差异有显著性（P〈0．05）。MMC和5-Fu对供瘤病人化疗一个疗程，病人骨痛症状消失或明显减轻，SPECT示个别骨转移灶消失，多个骨转移灶缩小。结论 E—ADM化疗可以诱导肿瘤组织MDR1和LRP表达升高；5-Fu化疗则可诱导LRP表达升高。裸鼠原位种植瘤敏感的化疗药物同样供瘤病人也敏感。     

Characterization of a highly metastatic, orthotopic lung cancer model in the nude rat

The prevailing subcutaneous nude rodent tumor xenograft models used for biological and preclinical studies do not optimally reflect some important biological properties of cancer, especially invasion and metastasis. Orthotopic models have been developed to address this need. However, for lung cancer none of the available models are optimal, in that none originate from an orthotopic (bronchial) primary site and exhibit extensive extrathoracic metastasis. Our goal was to develop a consistent rodent model of non-small cell lung cancer with both of these properties. Groups of male Rowett nude rats were given 500 rads of gamma radiation and then endobronchially implanted in the right caudal lobe airway with 50 mg of small NCI-H460 tumor fragments taken from an orthotopic donor tumor. They were then sacrificed at selected post-implantation times and evaluated grossly and histologically for animal weight, primary tumor take and size, and metastatic tumor incidence at multiple sites. At a late time point (32–35 days), consistency of primary tumor size and metastasis was estimated by comparing results from four groups of rats implanted on different occasions. The results showed that the primary tumors grew steadily, reaching four grams by days 32–35. Rats gained weight until days 14 to 21, but then began to show cachexia. High metastatic rates (>60%) were seen for mediastinal lymph nodes (by 21 days), and kidney, bone and brain (by 28 days). Mean primary tumor size and the incidences of both regional and systemic metastasis were consistent at 32–35 days in four different groups of six animals. In conclusion, this orthotopic lung cancer model is highly metastatic and consistent in terms of both primary tumor growth and metastatic behavior. It is the only available rodent model of human lung cancer emanating from an endobronchial site and metastasizing to multiple extrapulmonary sites, and should be very useful for both biological and preclinical studies of lung cancer, particularly where studies of antimetastatic activity are of interest, and/or where survival studies are desired.     

Influence of regional location of the inoculation site and dietary fat on the pathology of MDA-MB-435 human breast cancer cell-derived tumors grown in nude mice

The effects of inoculation site and dietary fat intake on the growth and metastasis of the MDA-MB-435 human breast cancer cell line were studied in athymic nude mice. The tumor cells, 1 × 10⁶, were injected into either a right-sided thoracic or inguinal mammary fat pad (mfp), and 1 week later mice were randomly assigned to a high-fat (HF), 23% corn oil, or a low-fat (LF), 5% corn oil, diet. There were 30 mice in the HF, and 30 in the LF subgroups from each of the two inoculation site groups. The experiment was terminated 15 weeks after the tumor cell inoculations. Within the thoracic mfp-injected group, a HF diet reduced latency, increased growth rate at the primary site, and enhanced metastasis to regional lymph nodes, lungs, and intra-abdominal sites. For mice inoculated into an inguinal mfp, fat intake affected neither primary nor metastatic tumor development and growth; in both subgroups lung metastasis was significantly less than in the HF-fed, thoracic mfp-injected subgroup. The histological features of the lung metastases were consistent with a vascular mode of spread, whereas the extensive intra-abdominal lymph node involvement observed in mice with inguinal mfp tumors was in keeping with lymphatic-borne metastases.     

A novel spontaneous metastasis model of human osteosarcoma developed using orthotopic transplantation of intact tumor tissue into tibia of nude mice

Evaluation of potential new treatment strategies requires adequate experimental tumor models which resemble the clinical situation as closely as possible. The purpose of the present study was to establish a new human osteosarcoma spontaneous metastasis model using orthotopic transplantation of histologically intact tumor tissue into the tibia of nude mice. Intact tumor pieces, obtained from the 32nd serial passage of subcutaneously growing human osteosarcoma xenografts, were implanted into the proximal tibia in 31 nude mice. Animals were sacrificed and autopsied 2, 4, 6, and 8 weeks after transplantation and examined macroscopically and microscopically for local tumor growth and metastases. All mice developed local intratibial bone tumors that were radiographically and histologically similar to primary human osteosarcoma. Lung metastases were observed in all mice, local and distant lymph node metastases in 15 (48%), and liver metastases in 6 (19%) mice. The microscopic appearance of the metastases was similar to that observed in the donor patientÕs tumor, corresponding subcutaneous xenografts and orthotopically transplanted intratibial tumors. This spontaneous metastasis model of human osteosarcoma in nude mice may resemble a clinical situation and could thus be useful for studies on local tumor growth, metastasis formation and therapy.     

内皮抑素对结肠癌增殖和转移抑制效应的实验观察

目的研究内皮抑素对结肠癌增殖和转移的抑制作用,并探讨基质金属蛋白酶13(MMP13)对结肠癌血管生成的作用。方法采用人结肠癌细胞株SW1116完整组织块于裸小鼠原位种植,建立结肠癌转移裸小鼠模型。种植后第1周开始皮下注射内皮抑素,每天1次,剂量为0mg/kg(对照组)、5mg/kg(实验Ⅰ组)、10mg/kg(实验Ⅱ组)、20mg/kg(实验Ⅲ组),共用6周。种植后第7周处死动物,测量原位肿瘤体积、抑瘤率,检测MMP13、微血管密度(MVD),观察腹膜、肝脏及其它脏器转移情况。结果内皮抑素剂量为0、5、10和20mg/kg时,原位肿瘤体积分别为(1.42±0.45)、(0.54±0.38)、(0.31±0.28)、(0.22±0.16)cm3;抑瘤率分别为0、62.0%、78.2%、84.5%;MMP13分别为81.8%、58.3%、42.9%、21.4%;MVD分别为(11.20±3.9)、(6.10±2.6)、(2.40±1.6)、(1.22±0.4);腹膜转移率分别为81.8%、50.0%、28.5%、7.1%;肝脏转移率分别为63.6%、33.3%、14.3%、0。实验Ⅰ～Ⅲ组与对照组相比,组间结肠癌增殖与转移的抑制作用差异有显著性(P<0.05)。结论MMP13可能是结肠癌重要的促血管生成因素之一;内皮抑素通过抑制肿瘤血管生成,对裸小鼠结肠癌增殖和转移均有抑制作用。     

Comparative studies between nude and scid mice on the growth and metastatic behavior of xenografted human tumors

The growth and metastatic behavior of three human tumor cell lines and a human colon carcinoma previously passagedin vivo were compared between nude mice and scid mice after xenotransplantation. The three human tumor lines included a bladder carcinoma (T24B), a melanoma (RPMI 7931) and alacZ gene-transduced breast cancer (MDA-MB-435 BAG). ThelacZ gene codes for -galactosidase, which can be stained blue with chromogenic substrate X-gal, thus allowing the highly sensitive detection and quantitative examination of human cancer metastasis in host mice. Adult (7–14 weeks) NMRI nude and C.B-17 SCID mice were inoculated with 0.5–5 × 10⁶ tumor cells s.c. Comparable take rate, latent period and growth rate of implanted tumors were observed in nude and scid mice for each of the cell lines tested. At the time of autopsy, which varied from 6 to 11 weeks after inoculation, a significantly higher incidence of spontaneous lung metastasis was discovered in scid mice (96%) than in age-matched nude mice (27%, totalP < 0.001).In vitro assays for NK cell-mediated cytotoxicity revealed no significant differences between the two strains of mice. Our results suggest that nude and scid mice are equally suitable for propagating human tumors. However, the metastatic capacity of human tumor cells appears to be better expressed in scid mice. Scid mice may therefore provide an advantageous model for the study of human tumor metastasis.