Biomedical subjects

Ping Jiang

Publications and source records attributed to Ping Jiang.

At least 73 records · Page 4Linked to original sources

PubMed2004

Development of a green fluorescent protein metastatic-cancer chick-embryo drug-screen model.

The chick-embryo model has been an important tool to study tumor growth, metastasis, and angiogenesis. However, an imageable model with a genetic fluorescent tag in the growing and spreading cancer cells that is stable over time has not been developed. We report here the development of such an imageable fluorescent chick-embryo metastatic cancer model with the use of green fluorescent protein (GFP). Lewis lung carcinoma cells, stably expressing GFP, were injected on the 12th day of incubation in the chick embryo. GFP-Lewis lung carcinoma metastases were visualized by fluorescence, after seven days additional incubation, in the brain, heart, and sternum of the developing chick embryo, with the most frequent site being the brain. The combination of streptokinase and gemcitabine was evaluated in this GFP metastatic model. Twelve-day-old chick embryos were injected intravenously with GFP-Lewis lung cancer cells, along with these two agents either alone or in combination. The streptokinase-gemcitabine combination inhibited metastases at all sites. The effective dose of gemcitabine was found to be 10 mg/kg and streptokinase 2000 IU per embryo. The data in this report suggest that this new stably fluorescent imageable metastatic-cancer chick-embryo model will enable rapid screening of new antimetastatic agents.

Animals↗

PubMed2004

[Comparison of TGF-beta1 expression of lung cancer in Gejiu miners with that in non-miners in other regions].

OBJECTIVE: To investigate the different expression of transforming growth factor beta(1) (TGF-beta(1)) in lung cancer specimens of Gejiu miners, and non-miners in other regions. METHODS: Thirty specimens of Gejiu miners' lung cancer and 30 specimens of non-miners' were observed in this experiment. The expression of TGF-beta(1) protein and TGF-beta(1) mRNA were detected by the methods of immunohistochemistry and in situ hybridization. The results were quantitatively analyzed using image analysis system. RESULTS: The positive rate of TGF-beta(1) protein expression in Gejiu miners and non-miners was 75.39%and 44.78% respectively, and the positive rate of TGF-beta(1) mRNA was 63.96% and 34.07% respectively. There were significant differences between the two groups (P < 0.01). CONCLUSION: The expression of TGF-beta(1) in lung cancer of Gejiu miners was significantly higher than that of non-miners. The pathogenesis of lung cancer may be different between Gejiu miner and non-miners. High expression of TGF-beta(1) may be one of the reasons of high incidence of lung cancer in Gejiu miners.

Humans↗

PubMed2004

[Peri-uvulopalatopharyng oplasty otoacoustic emissions in patients with obstructive sleep apnea-hypopnea syndrome].

OBJECTIVE: To study the cochlear function of patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). METHODS: Transiently evoked otoacoustic emissions (TEOAEs) and Distortion-product otoacoustic emissions(DPOAEs) of 28 patients with OSAHS were measured one week before uvulopalatopharyngoplasty (UPPP) and six months after UPPP. RESULTS: In these patients the prevalence of TEOAEs was 64.3%, its spectral energy was mainly distributed between 0.5-2 kHz, the amplitudes of DPOAEs between 0.5-8 kHz were reduced significantly, the prevalences of DPOAEs at 0.5-8 kHz were between 46.4%-89.3%. After UPPP, the prevalences of TEOAEs and DPOAEs were increased, the amplitudes of DPOAEs were in turn (22.50 +/- 16.70) dB SPL, (5.83 +/- 2.69) dB SPL, (0.69 +/- 3.83) dB SPL, (-2.50 +/- 2.45) dB SPL, (4.95 +/- 2.65) dB SPL, (4.48 +/- 3.07) dB SPL from 0.5 kHz to 8 kHz, the amplitudes of DPOAEs were significantly increased at 1 kHz, 2 kHz, 4 kHz, 6 kHz, 8 kHz. CONCLUSION: OSAHS can affect the cochlear function of the patients with OSAHS, UPPP can improve the cochlear function.

Adult↗

PubMed2004

Altered subcellular distribution of nucleolar protein fibrillarin by actinomycin D in HEp-2 cells.

AIM: To study the effects of actinomycin D on subcellular distribution of nucleolar protein fibrillarin in HEp-2 (human esophageal epithelial type 2) cells, and molecular mechanisms for maintenance of fibrillarin in nucleolus. METHODS: Indirect immunofluorescence assay was employed to investigate subcellular distribution of nucleolar protein fibrillarin and immunoblotting analysis was used to detect the total cellular amount of fibrillarin. RESULTS: Control cells with no drug treatment showed bright clumpy nucleolar staining, which indicated that fibrillarin decorated the nucleolus only. Treatment with actinomycin D caused dislocation of fibrillarin from nucleoli to nucleoplasm with numerous stained small nucleoplasmic entities. Immunoblotting showed that neither total cellular amount of fibrillarin nor the integrity of fibrillarin was changed upon the treatment. The dislocation of fibrillarin in cells treated at a lower concentration (0.05 mg/L) of actinomycin D, was totally reversible after removal of the drug from the medium. However, this reversion was not observed at a high drug concentration (1 mg/L). CONCLUSION: Actinomycin D induced dislocation of fibrillarin from nucleoli to nucleoplasm in HEp-2 cells. The retention of fibrillarin within the nucleolus was related to active RNA synthesis.

Cell Nucleolus↗

PubMed2004

[Landscape pattern variation of forest resources in typical forest zone of Changbai Mountains].

Based on GIS and RS data of 1985 and 1999 and the ground information from Lushuihe Forest Bureau, this paper studied the forest landscape pattern and its changes in typical forest zone of Changbai Mountains. According to the standard variance of patch areas in 1985 and 1999, the patch area distribution of mature conifer forest, mature broad-leaved forest, middle-aged conifer forest, and middle-aged broad-leaved forest was less symmetrical, showing that these land covers had landscape diversity and species diversity. According to landscape similarity index, the mature conifer forest, mature broad-leaved forest, middle-aged conifer forest and middle-aged broad-leaved forest, which were relatively stable than other land covers, made the majority of the landscape in the study area. According to patch density, the porosity of wetland was high in 1985 and 1999, indicating that wetland had little homogenization and formed more mosaics. The fragmentation extent of farming land, due to multiple cultivating types, azimuths and shapes, was high in both phases. Attributing greatly to anthropogenic factors, the fragmentation extent of wetland was high all along. In brief, the forest landscape pattern was changed greatly in the studied phases, and human activities affected heavily on it.

Biodiversity↗

PubMed2003

Inverse correlation between heparan sulfate composition and heparanase-1 gene expression in thyroid papillary carcinomas: a potential role in tumor metastasis.

PURPOSE: Heparanase-1 (HPR1) is an endoglycosidase that degrades the side chains of heparan sulfate proteoglycan (HSPG), a key component in cell surfaces, the extracellular matrix (ECM), and the basement membrane (BM). The purpose of this study was to evaluate HPR1 expression in thyroid neoplasms and its effect in degrading the HSPG substrates in the ECM and BM and to determine its role in thyroid tumor metastasis. EXPERIMENTAL DESIGN: HPR1 mRNA expression was analyzed by using in situ hybridization with a digoxigenin-labeled antisense RNA probe on paraffin-embedded tumor sections and reverse transcription-PCR (RT-PCR) in fresh tumor tissues. HPR1 protein expression was analyzed by using immunohistochemical staining with an anti-HPR1 rabbit antiserum and immunofluorescence (IF) with an anti-HPR1 monoclonal antibody. The effect of HPR1 expression in thyroid neoplasms was analyzed by examining the presence and integrity of the HSPG substrates in the ECM and BM using IF staining with a specific monoclonal antibody against heparan sulfate. The relationship of HPR1 expression in papillary thyroid carcinomas (PTCs) with various clinicopathological parameters was analyzed statistically. The role of HPR1 in thyroid tumor metastasis was further examined by comparing HPR1 levels in 10 thyroid tumor cell lines to their invasive and metastatic potential. RESULTS: In situ hybridization analysis of 81 tumor samples (62 papillary carcinomas and 19 follicular adenomas) revealed that HPR1 was expressed at a much higher frequency in PTCs than in follicular adenomas (P<0.05). RT-PCR analyses of fresh tumor tissues revealed that HPR1 mRNA could be detected in primary and metastatic thyroid papillary carcinomas. HPR1 expression was confirmed at the protein level by immunohistochemical staining and IF stainings. IF analysis of HSPG revealed that HS was deposited abundantly in the BM of normal thyroid follicles and benign follicular adenomas but was absent in most thyroid papillary carcinomas. A lack of heparan sulfate in PTCs inversely correlated with HPR1 expression. Clinicopathological data analyses revealed that PTCs with local and distant metastases scored HPR1 positive at a significantly higher frequency than nonmetastatic thyroid cancers (P=0.02). To further explore the role of HPR1 in tumor metastases, we characterized HPR1 expression in 10 thyroid tumor cell lines using RT-PCR and Western blot and measured HPR1 enzymatic activity using a novel ELISA. HPR1 was differentially expressed in different types of cell lines; overexpression of HPR1 in two tumor cell lines led to a dramatic increase of their invasive potential in vitro in an artificial BM. CONCLUSIONS: Our study suggests that HPR1 expressed in papillary carcinomas is functional and that HPR1 expression is associated with thyroid tumor malignancy and may significantly contribute to thyroid tumor metastases.

Adenoma↗

PubMed2003

Determination of clonality of metastasis by cell-specific color-coded fluorescent-protein imaging.

It has been thought that metastases are clonal and originate from rare cells in primary tumors that are heterogeneous in genotype and phenotype. Recent studies using DNA array analysis challenge this hypothesis and suggest the genetic background of the host is the important determinant of metastatic potential implying that metastases are not necessarily clonal. Previous methods to determine clonality of metastasis used karyotype or molecular analysis that were complicated, thereby limiting the number of metastatic colonies analyzed and the conclusions that could be drawn. We describe here the use of green fluorescent protein-labeled or red fluorescent protein-labeled HT-1080 human fibrosarcoma cells to determine clonality by simple fluorescence visualization of metastatic colonies after mixed implantation of the red and green fluorescent cells. Resulting pure red or pure green colonies were scored as clonal, whereas mixed yellow colonies were scored as nonclonal. In a spontaneous metastasis model originating from footpad injection in severe combined immunodeficient mice, 95% of the resulting lung colonies were either pure green or pure red, indicating monoclonal origin, whereas 5% were of mixed color, indicating polyclonal origin. In an experimental lung metastasis model established by tail vein injection in severe combined immunodeficient mice, clonality of lung metastasis was dependent on cell number. With a minimum cell number injected, almost all (96%) colonies were pure red or green and therefore monoclonal. When a large number of cells were injected, almost all (87%) colonies were mixed color and therefore heteroclonal. We conclude that spontaneous metastasis may be clonal because they are rare events, thereby supporting the rare-cell clonal origin of metastasis hypothesis. The clonality of the experimental metastasis model depended on the number of input cells. The simple fluorescence method of determining clonality of metastases described here can allow large-scale clonal analysis in numerous types of metastatic models.

Animals↗

PubMed2003

Dual-color fluorescence imaging distinguishes tumor cells from induced host angiogenic vessels and stromal cells.

We have developed a simple yet powerful technique for delineating the morphological events of tumor-induced angiogenesis and other tumor-induced host processes with dual-color fluorescence. The method clearly images implanted tumors and adjacent stroma, distinguishing unambiguously the host and tumor-specific components of the malignancy. The dual-color fluorescence imaging is effected by using red fluorescent protein (RFP)-expressing tumors growing in GFP-expressing transgenic mice. This model shows with great clarity the details of the tumor-stroma interaction, especially tumor-induced angiogenesis and tumor-infiltrating lymphocytes. The GFP-expressing tumor vasculature, both nascent and mature, could be readily distinguished interacting with the RFP-expressing tumor cells. GFP-expressing dendritic cells were observed contacting RFP-expressing tumor cells with their dendrites. GFP-expressing macrophages were observed engulfing RFP-expressing cancer cells. GFP lymphocytes were seen surrounding cells of the RFP tumor, which eventually regressed. Dual-color fluorescence imaging visualizes the tumor-host interaction by whole-body imaging and at the cellular level in fresh tissues, dramatically expanding previous studies in fixed and stained preparations.

Animals↗

PubMed2003

Prolonged dormancy and site-specific growth potential of cancer cells spontaneously disseminated from nonmetastatic breast tumors as revealed by labeling with green fluorescent protein.

This study used an isogenic pair of metastatic (M4A4) and nonmetastatic (NM2C5), green fluorescent protein-labeled human breast cancer cell lines derived from the same patient and inoculated into the mammary glands of nude mice to investigate the dissemination patterns and fate of cells that escaped spontaneously from the resulting tumors. After tumors appeared, fluorescing single tumor cells were regularly seen in the lungs, even in animals inoculated with NM2C5, which fails to form secondary tumors in other organs. The sensitivity of the technique confirmed the continuing presence of scattered NM2C5 cells after primary tumor resection, although they formed no metastases by 6 months. These self-disseminated human tumor cells were retrievable from the tissues and were still viable and malignant, manifested by indefinite proliferation in vitro and green fluorescence and local tumorigenicity in vivo. Therefore, these scattered tumor cells were still immortal but rendered indefinitely quiescent by the microenvironmental conditions in the lung tissue. This is the first unequivocal demonstration of spontaneous distant dissemination of human cancer cells by undisturbed nonmetastatic tumors and comprises a valuable system for the analysis of tumor dormancy. In contrast, although many of the cells disseminating from M4A4 tumors grew into fluorescing metastases in the lungs, others remained solitary and quiescent. Therefore, even in a clonally derived cell population with metastatic properties, many cells do not, or cannot, mobilize the organ-specific growth properties needed to generate metastases. This experimental approach, by using self-disseminating, green fluorescent protein-labeled, sister cell lines of opposing metastatic phenotypes, opens new avenues for investigating topics of clinical relevance, including tumor cell dormancy, anatomical distribution of metastases, and host factors influencing the metastatic process.

Animals↗

PubMed2003

Viable circulating metastatic cells produced in orthotopic but not ectopic prostate cancer models.

Elucidation of the mechanisms of hormone-independent metastatic prostate cancer remains a significant and highly relevant challenge. We report here that hormone-refractory human prostate carcinoma growing orthotopically efficiently deliver viable metastatic cells in the host circulation. This is in contrast to the ectopic tumors of the same lineage, which do not deliver live cells into the circulation. To investigate the malignant potential of viable circulating carcinoma cells, we developed a novel dual-color orthotopic coimplantation model of human prostate cancer metastasis in nude mice. This model is comprised of coinjection of an equivalent mixture of isolated and cultured circulating green fluorescent protein-expressing clones and parental red fluorescent protein-expressing human prostate carcinoma cells. In the dual-color model, the selected green fluorescent protein-labeled viable circulating cells have an increased metastatic propensity relative to the red fluorescent protein-labeled parental cells. The identification and isolation of highly malignant viable circulating human prostate carcinoma cells from orthotopic but not ectopic models will enable important new insights into the metastatic process including the role of the tumor microenvironment.

Animals↗

PubMed2003

Real-time GFP imaging of spontaneous HT-1080 fibrosarcoma lung metastases.

Metastasis to the lung is often a lethal event in sarcoma as well as other cancers. We report here a new animal model of sarcoma enabling the external real-time fluorescence imaging of spontaneous lung metastasis. The human fibrosarcoma cell line HT-1080 was transduced with the green fluorescent protein (GFP) gene. HT-1080-GFP cells were injected into the right hind footpad of severe combined immunodeficient (SCID) mice. The lung metastases were evaluated by whole-body fluorescence imaging as well as direct-view imaging in live animals through a skin-flap window over the chest wall. Spontaneous lung metastases were observed on the lungs of 11 of 12 mice. SCID mice well tolerated the skin-flap procedure enabling real-time imaging of spontaneous lung metastases with a resolution of approximately 50-100 microm. This procedure enabled external imaging at the micrometastasis level. Real-time evaluation of spontaneous lung metastasis in the same animals should allow drug evaluation and mechanistic studies not previously possible.

Animals↗

PubMed2003

Real-time imaging of individual fluorescent-protein color-coded metastatic colonies in vivo.

We have established stable, bright green fluorescent protein (GFP)- or red fluorescent protein (RFP)-expressing HT-1080 human fibrosarcoma clones. These cell lines showed similar cell proliferation rates and high-frequency experimental lung metastasis. The HT-1080-GFP and -RFP clones enable simultaneous real-time dual-color imaging in the live animal. HT-1080 cells were transduced with retroviral vectors containing GFP or RFP and the neomycin resistance gene. Stable transformants were selected stepwise with G418 up to 800 microl/ml. Subsequently, high GFP- or RFP-expressing clones, HT-1080-GFP or HT-1080-RFP, respectively, were selected. 3 x 10(6) cells from each clone were mixed and injected into the tail vein of SCID mice. The cells seeded the lung at high frequency with subsequent formation of pure green and pure red colonies as well as mixed yellow colonies with different patterns visualized directly on excised lungs. The lung metastases were also visualized by external fluorescence imaging in live animals through skin-flap windows over the chest wall. Lung metastases were observed on the lung surface of all mice. SCID mice well tolerated multiple surgical procedures for direct-view imaging via skin-flap windows. Real-time metastatic growth of the two different colored clones in the same lung was externally imaged with resolution and quantification of green, red, or yellow colonies in live animals. The color coding enabled determination of whether the colonies grew clonally or were seeded as a mixture with one cell type eventually dominating, or whether the colonies grew as a mixture. The simultaneous real-time dual-color imaging of metastatic colonies described in this report gives rise to the possibility of color-coded imaging of clones of cancer cells carrying various forms of gene of interest.

Animals↗

PubMed2003

AMPK-beta1 subunit is a p53-independent stress responsive protein that inhibits tumor cell growth upon forced expression.

In an effort to search for genes responsible for cell growth arrest and/or apoptosis associated with p53 signaling pathways, we profiled a human lung carcinoma line H1299, expressing a temperature-sensitive p53 (V138) against Affymetric human U95Av2 GeneChip A, consisting of 12 000 genes. 133 genes were identified that were either induced or repressed in response to p53-dependent cell growth arrest and apoptotic conditions. Among them, the beta1 subunit, but not other subunits of the AMP-activated protein kinase (AMPK) was strongly induced. The p53 consensus binding site search in the AMPK-beta1 promoter and the first intron identified four such putative sites. However, p53 failed to bind to any of these sites as assayed by in vitro gel retardation and in vivo chromatin immunoprecipitation. Furthermore, northern analysis showed that induction of this gene is independent of p53, as increased expression of the gene was observed in p53 null H1299/Neo control cells when the temperature was shifted to 32 degrees C. Moreover, a DNA damaging agent, etoposide, also induced beta1 subunit expression in multiple human tumor cells, regardless of p53 status. Thus, the beta1 subunit of AMPK is not a p53 downstream target gene, but can be induced by cold shock or the chemotherapeutic drug, etoposide in a p53-independent manner. To determine the biological significance of AMPK-beta1 induction, we over-expressed the gene in two tumor cell lines, H1299 and U2-OS. In both lines, forced AMPK-beta1 expression inhibits tumor cell growth, suggesting that AMPK-beta1 induction may facilitate stress-induced growth inhibition and cell killing.

AMP-Activated Protein Kinases↗

PubMed2003

[Changes of ECR1 genomic density polymorphism, quantitative expression and the activity of ECR1 natural adhesion in patients with chronic hepatitis].

OBJECTIVE: To study the changes of genomic density polymorphism, quantitative expression and the adhesion activity of complement receptor type 1 (ECR1) on erythrocytes in patients with chronic hepatitis. METHODS: Polymerase chain reaction (PCR) and Hind restriction enzyme digestion, the quantitative assay of ECR1 and the activity of erythrocytes immune adhesion test were applied. RESULTS: The spot mutation rate (25.0%-30.3%) of ECR1 density gene in patients with chronic hepatitis was not significantly different from that of healthy individuals (28.0%). The amount of ECR1 in patients with chronic hepatitis, except for the diseases with normal liver function, was significantly lower than that of healthy individuals (t=9.87,P<0.000 1). The quantitative expression of ECR1 in decompensated cirrhosis was obviously lower than that of compensated cirrhosis (t=2.21,P<0.05). CONCLUSIONS: Defective expression of ECR1 in chronic hepatitis B may be acquired through central and/or peripheral mechanisms. It is very important to study the quantitative expression in the patients with chronic hepatitis.

Erythrocytes↗

PubMed2003

[Effects of ultraviolet-C irradiation on membrane lipid peroxidation and activity of PS II electron transport in chloroplasts of Taxus cuspidata needles].

The isolated chloroplasts of Taxus cuspidata needles treated with 12 W.m-2 of ultraviolet-C (UV-C, 254 nm) irradiation were studied under laboratory conditions. The results showed that with the increase of UV-C irradiation, the carotenoids (Car) and glutathione (GSH) contents and superoxide dismutase (SOD) activity were decreased, while the malondialdehyde content (MDA) and the relative permeability of chloroplasts membrane were increased to various extents. The PS II electron transport activity was conspicuous decreased, which had a significant inverse ratio with photosynthetically active radiation (PAR). UV-C irradiation was insensitive on chlorophyll. The results indicated that membrane lipid peroxidation of chloroplasts caused by UV-C radiation was the reason of the decrease of PS II electron transport activity.

Chloroplasts↗

PubMed2002

[Safety of gene therapy within cochlea, experimental study with guinea pig].

OBJECTIVE: To observe the safety of inoculation of recombinant adenovirus with human neurotrophin-3 (Ad-NT3) into cochlea and its effect on hearing function. METHODS: Twenty healthy guinea pigs were randomly divided into two groups: ten animals were inoculated with Ad-NT3 into the perilymphatic space after a small hole was drilled in the bony wall near tympanic scala of the base turn, while the other ten were introduced with artificial perilymphatic fluid (APF) as controls. Auditory brainstem response (ABR) were recorded before, immediately after and seven days after the inoculation. Seven days after the surgery, the animals were killed. Frozen sections and colloidin sections of cochlea were made and observed under microscope. Immunohistochemistry was used to detect the expression of NT3 protein in cochlea. RESULTS: The mean ABR threshold values were (35 +/- 3.7) dB SPL and (35 +/- 3.2) dB SPL before the inoculation, (40 +/- 2.5) dB SPL and (40 +/- 3.0) dB SPL immediately after the inoculation, and (35 +/- 3.0) dB SPL and (35 +/- 3.0) dB SPL seven days after inoculation in the Ad-NT3 group and AFP group respectively (all P > 0.05). The ABR-III latency of 100dB SPL click was (2.812 +/- 0.087) ms and (2.824 +/- 0.121) ms before inoculation, (2.793 +/- 0.093) ms and (2.796 +/- 0.095) ms immediately after inoculation, and (2.822 +/- 0.102) ms and (2.834 +/- 0.135) ms seven days after inoculation in Ad-NT3 and AFP groups respectively (P > 0.05). No difference of ABR threshold and latency was observed at different time points in both groups. Ad-NT3 protein was expressed within each turn of the cochlea, including spiral limbus, spiral ligament and ganglion cells. The cochlear structure remained intact with no sign of infection or cell degeneration. CONCLUSION: Gene therapy by means of introduction of trace AdNT3 into the perilymphatic space through pore in tympanic scala is safe, causing no structure change or hearing loss.

Adenoviridae↗

PubMed2002

Targeted deletion of the MLC1f/3f downstream enhancer results in precocious MLC expression and mesoderm ablation.

The expression of skeletal muscle contractile proteins is tightly regulated during embryonic development. In the mouse, the myosin light chain (MLC) 1f/3f gene locus is not activated until E9.5, exclusively in skeletal muscle precursor cells. A potent enhancer downstream of the MLC1f/3f locus confers correct temporal and spatial activation of linked reporter gene in transgenic mouse embryos. To examine roles of the MLC downstream enhancer (MLCE) in its native context of the MLC1f/3f gene locus, we eliminated a 1.5-kb DNA segment containing the enhancer from the mouse genome by targeted deletion, leaving no exogenous sequences at the deletion site. Mouse embryos homozygous for the MLCE deletion were smaller and developmentally delayed, formed no mesoderm by E7.5, and were resorbed almost completely at E8.5. In situ hybridization and RT-PCR analyses of affected mutant embryos at E7.5 revealed ectopic MLC transcripts, whose products would be predicted to interfere with a variety of nonmuscle cell functions determining differentiation of mesoderm. These results suggest that the MLC downstream enhancer and its flanking sequences include negative regulatory elements which block precocious activation of MLC expression in mesodermal precursors during a critical window of development, as well as positive elements which subsequently permit tissue-restricted MLC transcription in differentiating skeletal muscles.

Animals↗

PubMed2002

Direct external imaging of nascent cancer, tumor progression, angiogenesis, and metastasis on internal organs in the fluorescent orthotopic model.

Mouse tumor models have undergone profound improvements in the fidelity of emulating human disease. Replacing ectopic s.c. implantation with organ-specific orthotopic implantation reproduces human tumor growth and metastasis. Strong fluorescent labeling with green fluorescent protein along with inexpensive video detectors, positioned externally to the mouse, allows the monitoring of details of tumor growth, angiogenesis, and metastatic spread. However, the sensitivity of external imaging is limited by light scattering in intervening tissue, most especially in skin. Opening a reversible skin-flap in the light path markedly reduces signal attenuation, increasing detection sensitivity many-fold. The observable depth of tissue is thereby greatly increased and many tumors that were previously hidden are now clearly observable. This report presents tumor images and related quantitative growth data previously impossible to obtain. Single tumor cells, expressing green fluorescent protein, were seeded on the brain image through a scalp skin-flap. Lung tumor microfoci representing a few cells are viewed through a skin-flap over the chest wall, while contralateral micrometastases were imaged through the corresponding skin-flap. Pancreatic tumors and their angiogenic microvessels were imaged by means of a peritoneal wall skin-flap. A skin-flap over the liver allowed imaging of physiologically relevant micrometastases originating in an orthotopically implanted tumor. Single tumor cells on the liver arising from intraportal injection also were detectable. Possible future technical developments are suggested by the image, through a lower-abdominal skin-flap, of an invasive prostate tumor expressing both red and green fluorescent proteins in separate colonies.

Animals↗