Weili Fu | GSK - Academia.edu (original) (raw)
Papers by Weili Fu
Cancer Research, 2004
1456 The S100A4/mts-1/metastasin gene is known to be associated with the metastatic phenotype of ... more 1456 The S100A4/mts-1/metastasin gene is known to be associated with the metastatic phenotype of several tumor types. Our previous findings showed downregulation of the S100A4 gene in HCT116 knock out cell lines expressing only wild type beta-catenin. In order to evaluate the causal role of beta-catenin in regulating S100A4, we created beta-catenin-transfectants of the naturally beta-catenin nullosomic tumor cell line NCI-H28. We generated stable transfectants containing wild type beta-catenin, mutated beta-catenin (position 45 in exon 3), and both variants (beta-catenin plasmids were kindly provided by B. Vogelstein, MD). Transfectants were characterized by real time PCR with probes designed to discriminate between wild type vs. mutated beta-catenin. In clones harboring the mutated beta-catenin, either exclusively or in combination with the wild type beta-catenin, S100A4 mRNA levels were increased (maximum-70-fold), as determined by quantitative real time RT-PCR. In contrast, in cl...
Clinical Cancer Research, 2006
Background: The current paradigm suggests that matrix metalloproteinase 9 (MMP-9) expressed by st... more Background: The current paradigm suggests that matrix metalloproteinase 9 (MMP-9) expressed by stromal cells is a therapeutic target in human colorectal tumors which presumably regulates metastatic disease progression. Conversely, whereas cancer cells within those tumors may induce stromal cells to produce MMP-9 and may be targets for MMP-9 activity, they are not the source of MMP-9 underlying metastasis. Methods: MMP-9 expression in matched colorectal tumors and normal adjacent mucosa from patients and human colon cancer cell lines was examined by real-time reverse transcription-PCR, laser capture microdissection, immunoelectron microscopy, and immunoblot analysis. The role of colon cancer cell MMP-9 in processes underlying metastasis was explored in vitro by examining degradation of extracellular matrix components by gelatin zymography and formation of locomotory organelles by cell spreading analysis and in vivo by quantifying hematogenous tumor cell seeding of mouse lungs. Result...
Cancer Research, 2004
Coagulation has long been known to facilitate metastasis. To pinpoint the steps where coagulation... more Coagulation has long been known to facilitate metastasis. To pinpoint the steps where coagulation might play a role in the metastasis, we used three-dimensional visualization of direct infusion of fluorescence labeled antibody to observe the interaction of tumor cells with platelets and fibrinogen in isolated lung preparations. Tumor cells arrested in the pulmonary vasculature were associated with a clot composed of both platelets and fibrin(ogen). Initially, the cells attached to the pulmonary vessels were rounded. Over the next 2 to 6 hours, they spread on the vessel surface. The associated clot was lysed coincident with tumor cell spreading. To assess the importance of clot formation, we inhibited coagulation with hirudin, a potent inhibitor of thrombin. The number of tumor cells initially arrested in the lung of hirudin-treated mice was essentially the same as in control mice. However, tumor cell spreading and subsequent retention of the tumor cells in the lung was markedly inhi...
Cancer Letters, 2004
The presence of metastases indicates an ominous prognosis in patients with malignancies, yet the ... more The presence of metastases indicates an ominous prognosis in patients with malignancies, yet the factors that distinguish metastatic from non-metastatic tumors remain poorly understood. Here we pursued the hypothesis that apoptosis in vivo would distinguish metastatic cells from non-metastatic cells and developed a novel method for observation of apoptosis induction in living cells. One hour after the infusion of metastatic or non-metastatic human melanoma or transformed rat embryo fibroblasts, arrest of tumor cells in the pulmonary vasculature was equivalent. In order to demonstrate the induction of apoptosis in living cells, we observed the translocation of cytoplasmic BAD-GFP fusion proteins to the mitochondria during apoptosis. Microscopic observation of the tumor cells transfected with BAD-GFP in isolated lung preparations after intravenous injection into nu/nu mice revealed translocation of BAD-GFP in many more of the arrested, non-metastatic melanoma or transformed rat embryo cells over 4-24 h than of the metastatic cells. TUNEL staining confirmed enhanced apoptosis by non-metastatic tumor cells after injection in vivo. Metastatic melanoma cells or metastatic embryo fibroblasts were better able to negotiate the barrier of survival in the circulation after pulmonary arrest than non-metastatic cells confirming the hypothesis that susceptibility to apoptosis after arrest in the pulmonary vasculature distinguishes metastatic from non-metastatic cells and introducing a new assay for in vivo induction of apoptosis.
The American Journal of Pathology, 2002
Supported by the Susan G. Komen Breast Cancer Foundation (grant no. 99-003201 to A. A.) and the N... more Supported by the Susan G. Komen Breast Cancer Foundation (grant no. 99-003201 to A. A.) and the National Cancer Institute (grants RO1 CA-46830 and RO1 CA 89188 to R. J. M.).
Journal of Cell Biology, 2004
Arrest of circulating tumor cells in distant organs is required for hematogenous metastasis, but ... more Arrest of circulating tumor cells in distant organs is required for hematogenous metastasis, but the tumor cell surface molecules responsible have not been identified. Here, we show that the tumor cell α3β1 integrin makes an important contribution to arrest in the lung and to early colony formation. These analyses indicated that pulmonary arrest does not occur merely due to size restriction, and raised the question of how the tumor cell α3β1 integrin contacts its best-defined ligand, laminin (LN)-5, a basement membrane (BM) component. Further analyses revealed that LN-5 is available to the tumor cell in preexisting patches of exposed BM in the pulmonary vasculature. The early arrest of tumor cells in the pulmonary vasculature through interaction of α3β1 integrin with LN-5 in exposed BM provides both a molecular and a structural basis for cell arrest during pulmonary metastasis.
Genome …, 1997
The Drosophila eyes absent (eya) gene plays an essential role in the events that lead to proper d... more The Drosophila eyes absent (eya) gene plays an essential role in the events that lead to proper development of the fly eye and embryo. Here we report the analysis of two human and two mouse homologs of the fly eya gene. Sequence comparison reveals a large domain of-270 amino acids in the carboxyl terminus of the predicted mammalian proteins that shows 53% identity between the fly sequence and all of the vertebrate homologs. This Eya-homology domain is of novel sequence, with no previously identified motifs. RNA hybridization studies indicate that the mouse genes are expressed during embryogenesis and in select tissues of the adult. Both mouse 128 @ GENOME RESEARCH
The EMBO Journal, 1999
A.Bashirullah, S.R.Halsell and R.L.Cooperstock contributed equally to this work Maternally synthe... more A.Bashirullah, S.R.Halsell and R.L.Cooperstock contributed equally to this work Maternally synthesized RNAs program early embryonic development in many animals. These RNAs are degraded rapidly by the midblastula transition (MBT), allowing genetic control of development to pass to zygotically synthesized transcripts. Here we show that in the early embryo of Drosophila melanogaster, there are two independent RNA degradation pathways, either of which is sufficient for transcript elimination. However, only the concerted action of both pathways leads to elimination of transcripts with the correct timing, at the MBT. The first pathway is maternally encoded, is targeted to specific classes of mRNAs through cis-acting elements in the 3Ј-untranslated region and is conserved in Xenopus laevis. The second pathway is activated 2 h after fertilization and functions together with the maternal pathway to ensure that transcripts are degraded by the MBT.
Journal of Neurobiology, 2001
Circadian rhythms in Drosophila depend upon expression of the timeless (tim) and period (per) gen... more Circadian rhythms in Drosophila depend upon expression of the timeless (tim) and period (per) genes, which encode interacting components of the endogenous clock. These two clock genes show a robust circadian oscillation in transcription rate as well as RNA and protein levels. Transcriptional activation of both genes requires the basic helix-loop-helix (bHLH) PAS transcription factors dCLOCK (dCLK) and CYCLE (CYC), which bind E-box elements. We investigated the role of E-box elements in regulating behavioral rhythmicity and tim gene expression. We show that mutation of the upstream E-box in the tim gene prevents the rescue by tim cDNA sequences of the arrhythmic tim 01 phenotype. RNA encoded by this mutated tim transgene fails to cycle and is expressed at low levels. While a tim transgene carrying a wild-type E-box restores behavioral rhythms, tim RNA levels are intermediate to those of the mutant E-box transgenic lines and wild type, and do not display high amplitude cycling. On the other hand, high-amplitude RNA cycling was consistently ob-tained with a tim transgene that contains genomic, rather than cDNA, sequences. To identify additional sequences that may be required for tim cycling, we investigated the role of an E-box in the first intron of the tim gene through cell culture experiments. In these experiments, the presence of this intron did not have any effect on the activation of tim transcription by dCLK/ CYC. As the upstream E-box was implicated in activation by dCLK/CYC in cell culture, we assayed sequences containing this E-box for association with proteins in fly head extracts. These studies provide the first biochemical evidence for an in vivo complex containing dCLK and CYC that binds the tim upstream sequence and is detected at all times of day. Together, these data highlight molecular mechanisms that are critical for behavioral rhythms.
Cancer Research, 2009
Matrix metalloproteinase 9 (MMP-9) produced by colorectal cancer cells is a critical determinant ... more Matrix metalloproteinase 9 (MMP-9) produced by colorectal cancer cells is a critical determinant of metastatic disease progression and an attractive target for antimetastatic strategies to reduce colon cancer mortality. Cellular signaling by cGMP regulates MMP-9 dynamics in various cell systems and the bacterial enterotoxin receptor guanylyl cyclase C (GCC), the principle source of cGMP in colonocytes which is overexpressed in colorectal cancers, inhibits tumor initiation and progression in the intestine. Here, we demonstrate that ligand-dependent GCC signaling through cGMP induces functional remodeling of cancer cell MMP-9 reflected by a compartmental redistribution of this gelatinase, in which intracellular retention resulted in reciprocal extracellular depletion. Functional remodeling of MMP-9 by GCC signaling reduced the ability of colon cancer cells to degrade matrix components, organize the actin cytoskeleton to form locomotory organelles and spread, and hematogenously seed distant organs. Of significance, GCC effects on cancer cell MMP-9 prevented establishment of metastatic colonies by colorectal cancer cells in the mouse peritoneum in vivo. Since endogenous hormones for GCC are uniformly deficient in intestinal tumors, reactivation of dormant GCC signaling with exogenous administration of GCC agonists may represent a specific intervention to target MMP-9 functions in colon cancer cells. The notion that GCC-mediated regulation of cancer cell MMP-9 disrupts metastasis, in turn, underscores the unexplored utility of GCC hormone replacement therapy in the chemoprevention of colorectal cancer progression.
Cancer Research, 2004
Coagulation has long been known to facilitate metastasis. To pinpoint the steps where coagulation... more Coagulation has long been known to facilitate metastasis. To pinpoint the steps where coagulation might play a role in the metastasis, we used three-dimensional visualization of direct infusion of fluorescence labeled antibody to observe the interaction of tumor cells with platelets and fibrinogen in isolated lung preparations. Tumor cells arrested in the pulmonary vasculature were associated with a clot composed of both platelets and fibrin(ogen). Initially, the cells attached to the pulmonary vessels were rounded. Over the next 2 to 6 hours, they spread on the vessel surface. The associated clot was lysed coincident with tumor cell spreading. To assess the importance of clot formation, we inhibited coagulation with hirudin, a potent inhibitor of thrombin. The number of tumor cells initially arrested in the lung of hirudin-treated mice was essentially the same as in control mice. However, tumor cell spreading and subsequent retention of the tumor cells in the lung was markedly inhibited in the anticoagulated mice. These associations of the tumor cells with platelets were independent of tumor cell expression of P-selectin ligands. This work identifies tumor cell spreading onto the vascular surface as an important component of the metastatic cascade and implicates coagulation in this process.
The American Journal of Pathology, 2002
Supported by the Susan G. Komen Breast Cancer Foundation (grant no. 99-003201 to A. A.) and the N... more Supported by the Susan G. Komen Breast Cancer Foundation (grant no. 99-003201 to A. A.) and the National Cancer Institute (grants RO1 CA-46830 and RO1 CA 89188 to R. J. M.).
Cancer Letters, 2004
The presence of metastases indicates an ominous prognosis in patients with malignancies, yet the ... more The presence of metastases indicates an ominous prognosis in patients with malignancies, yet the factors that distinguish metastatic from non-metastatic tumors remain poorly understood. Here we pursued the hypothesis that apoptosis in vivo would distinguish metastatic cells from non-metastatic cells and developed a novel method for observation of apoptosis induction in living cells. One hour after the infusion of metastatic or non-metastatic human melanoma or transformed rat embryo fibroblasts, arrest of tumor cells in the pulmonary vasculature was equivalent. In order to demonstrate the induction of apoptosis in living cells, we observed the translocation of cytoplasmic BAD-GFP fusion proteins to the mitochondria during apoptosis. Microscopic observation of the tumor cells transfected with BAD-GFP in isolated lung preparations after intravenous injection into nu/nu mice revealed translocation of BAD-GFP in many more of the arrested, non-metastatic melanoma or transformed rat embryo cells over 4-24 h than of the metastatic cells. TUNEL staining confirmed enhanced apoptosis by non-metastatic tumor cells after injection in vivo. Metastatic melanoma cells or metastatic embryo fibroblasts were better able to negotiate the barrier of survival in the circulation after pulmonary arrest than non-metastatic cells confirming the hypothesis that susceptibility to apoptosis after arrest in the pulmonary vasculature distinguishes metastatic from non-metastatic cells and introducing a new assay for in vivo induction of apoptosis.
Cancer Research, 2004
1456 The S100A4/mts-1/metastasin gene is known to be associated with the metastatic phenotype of ... more 1456 The S100A4/mts-1/metastasin gene is known to be associated with the metastatic phenotype of several tumor types. Our previous findings showed downregulation of the S100A4 gene in HCT116 knock out cell lines expressing only wild type beta-catenin. In order to evaluate the causal role of beta-catenin in regulating S100A4, we created beta-catenin-transfectants of the naturally beta-catenin nullosomic tumor cell line NCI-H28. We generated stable transfectants containing wild type beta-catenin, mutated beta-catenin (position 45 in exon 3), and both variants (beta-catenin plasmids were kindly provided by B. Vogelstein, MD). Transfectants were characterized by real time PCR with probes designed to discriminate between wild type vs. mutated beta-catenin. In clones harboring the mutated beta-catenin, either exclusively or in combination with the wild type beta-catenin, S100A4 mRNA levels were increased (maximum-70-fold), as determined by quantitative real time RT-PCR. In contrast, in cl...
Clinical Cancer Research, 2006
Background: The current paradigm suggests that matrix metalloproteinase 9 (MMP-9) expressed by st... more Background: The current paradigm suggests that matrix metalloproteinase 9 (MMP-9) expressed by stromal cells is a therapeutic target in human colorectal tumors which presumably regulates metastatic disease progression. Conversely, whereas cancer cells within those tumors may induce stromal cells to produce MMP-9 and may be targets for MMP-9 activity, they are not the source of MMP-9 underlying metastasis. Methods: MMP-9 expression in matched colorectal tumors and normal adjacent mucosa from patients and human colon cancer cell lines was examined by real-time reverse transcription-PCR, laser capture microdissection, immunoelectron microscopy, and immunoblot analysis. The role of colon cancer cell MMP-9 in processes underlying metastasis was explored in vitro by examining degradation of extracellular matrix components by gelatin zymography and formation of locomotory organelles by cell spreading analysis and in vivo by quantifying hematogenous tumor cell seeding of mouse lungs. Result...
Cancer Research, 2004
Coagulation has long been known to facilitate metastasis. To pinpoint the steps where coagulation... more Coagulation has long been known to facilitate metastasis. To pinpoint the steps where coagulation might play a role in the metastasis, we used three-dimensional visualization of direct infusion of fluorescence labeled antibody to observe the interaction of tumor cells with platelets and fibrinogen in isolated lung preparations. Tumor cells arrested in the pulmonary vasculature were associated with a clot composed of both platelets and fibrin(ogen). Initially, the cells attached to the pulmonary vessels were rounded. Over the next 2 to 6 hours, they spread on the vessel surface. The associated clot was lysed coincident with tumor cell spreading. To assess the importance of clot formation, we inhibited coagulation with hirudin, a potent inhibitor of thrombin. The number of tumor cells initially arrested in the lung of hirudin-treated mice was essentially the same as in control mice. However, tumor cell spreading and subsequent retention of the tumor cells in the lung was markedly inhi...
Cancer Letters, 2004
The presence of metastases indicates an ominous prognosis in patients with malignancies, yet the ... more The presence of metastases indicates an ominous prognosis in patients with malignancies, yet the factors that distinguish metastatic from non-metastatic tumors remain poorly understood. Here we pursued the hypothesis that apoptosis in vivo would distinguish metastatic cells from non-metastatic cells and developed a novel method for observation of apoptosis induction in living cells. One hour after the infusion of metastatic or non-metastatic human melanoma or transformed rat embryo fibroblasts, arrest of tumor cells in the pulmonary vasculature was equivalent. In order to demonstrate the induction of apoptosis in living cells, we observed the translocation of cytoplasmic BAD-GFP fusion proteins to the mitochondria during apoptosis. Microscopic observation of the tumor cells transfected with BAD-GFP in isolated lung preparations after intravenous injection into nu/nu mice revealed translocation of BAD-GFP in many more of the arrested, non-metastatic melanoma or transformed rat embryo cells over 4-24 h than of the metastatic cells. TUNEL staining confirmed enhanced apoptosis by non-metastatic tumor cells after injection in vivo. Metastatic melanoma cells or metastatic embryo fibroblasts were better able to negotiate the barrier of survival in the circulation after pulmonary arrest than non-metastatic cells confirming the hypothesis that susceptibility to apoptosis after arrest in the pulmonary vasculature distinguishes metastatic from non-metastatic cells and introducing a new assay for in vivo induction of apoptosis.
The American Journal of Pathology, 2002
Supported by the Susan G. Komen Breast Cancer Foundation (grant no. 99-003201 to A. A.) and the N... more Supported by the Susan G. Komen Breast Cancer Foundation (grant no. 99-003201 to A. A.) and the National Cancer Institute (grants RO1 CA-46830 and RO1 CA 89188 to R. J. M.).
Journal of Cell Biology, 2004
Arrest of circulating tumor cells in distant organs is required for hematogenous metastasis, but ... more Arrest of circulating tumor cells in distant organs is required for hematogenous metastasis, but the tumor cell surface molecules responsible have not been identified. Here, we show that the tumor cell α3β1 integrin makes an important contribution to arrest in the lung and to early colony formation. These analyses indicated that pulmonary arrest does not occur merely due to size restriction, and raised the question of how the tumor cell α3β1 integrin contacts its best-defined ligand, laminin (LN)-5, a basement membrane (BM) component. Further analyses revealed that LN-5 is available to the tumor cell in preexisting patches of exposed BM in the pulmonary vasculature. The early arrest of tumor cells in the pulmonary vasculature through interaction of α3β1 integrin with LN-5 in exposed BM provides both a molecular and a structural basis for cell arrest during pulmonary metastasis.
Genome …, 1997
The Drosophila eyes absent (eya) gene plays an essential role in the events that lead to proper d... more The Drosophila eyes absent (eya) gene plays an essential role in the events that lead to proper development of the fly eye and embryo. Here we report the analysis of two human and two mouse homologs of the fly eya gene. Sequence comparison reveals a large domain of-270 amino acids in the carboxyl terminus of the predicted mammalian proteins that shows 53% identity between the fly sequence and all of the vertebrate homologs. This Eya-homology domain is of novel sequence, with no previously identified motifs. RNA hybridization studies indicate that the mouse genes are expressed during embryogenesis and in select tissues of the adult. Both mouse 128 @ GENOME RESEARCH
The EMBO Journal, 1999
A.Bashirullah, S.R.Halsell and R.L.Cooperstock contributed equally to this work Maternally synthe... more A.Bashirullah, S.R.Halsell and R.L.Cooperstock contributed equally to this work Maternally synthesized RNAs program early embryonic development in many animals. These RNAs are degraded rapidly by the midblastula transition (MBT), allowing genetic control of development to pass to zygotically synthesized transcripts. Here we show that in the early embryo of Drosophila melanogaster, there are two independent RNA degradation pathways, either of which is sufficient for transcript elimination. However, only the concerted action of both pathways leads to elimination of transcripts with the correct timing, at the MBT. The first pathway is maternally encoded, is targeted to specific classes of mRNAs through cis-acting elements in the 3Ј-untranslated region and is conserved in Xenopus laevis. The second pathway is activated 2 h after fertilization and functions together with the maternal pathway to ensure that transcripts are degraded by the MBT.
Journal of Neurobiology, 2001
Circadian rhythms in Drosophila depend upon expression of the timeless (tim) and period (per) gen... more Circadian rhythms in Drosophila depend upon expression of the timeless (tim) and period (per) genes, which encode interacting components of the endogenous clock. These two clock genes show a robust circadian oscillation in transcription rate as well as RNA and protein levels. Transcriptional activation of both genes requires the basic helix-loop-helix (bHLH) PAS transcription factors dCLOCK (dCLK) and CYCLE (CYC), which bind E-box elements. We investigated the role of E-box elements in regulating behavioral rhythmicity and tim gene expression. We show that mutation of the upstream E-box in the tim gene prevents the rescue by tim cDNA sequences of the arrhythmic tim 01 phenotype. RNA encoded by this mutated tim transgene fails to cycle and is expressed at low levels. While a tim transgene carrying a wild-type E-box restores behavioral rhythms, tim RNA levels are intermediate to those of the mutant E-box transgenic lines and wild type, and do not display high amplitude cycling. On the other hand, high-amplitude RNA cycling was consistently ob-tained with a tim transgene that contains genomic, rather than cDNA, sequences. To identify additional sequences that may be required for tim cycling, we investigated the role of an E-box in the first intron of the tim gene through cell culture experiments. In these experiments, the presence of this intron did not have any effect on the activation of tim transcription by dCLK/ CYC. As the upstream E-box was implicated in activation by dCLK/CYC in cell culture, we assayed sequences containing this E-box for association with proteins in fly head extracts. These studies provide the first biochemical evidence for an in vivo complex containing dCLK and CYC that binds the tim upstream sequence and is detected at all times of day. Together, these data highlight molecular mechanisms that are critical for behavioral rhythms.
Cancer Research, 2009
Matrix metalloproteinase 9 (MMP-9) produced by colorectal cancer cells is a critical determinant ... more Matrix metalloproteinase 9 (MMP-9) produced by colorectal cancer cells is a critical determinant of metastatic disease progression and an attractive target for antimetastatic strategies to reduce colon cancer mortality. Cellular signaling by cGMP regulates MMP-9 dynamics in various cell systems and the bacterial enterotoxin receptor guanylyl cyclase C (GCC), the principle source of cGMP in colonocytes which is overexpressed in colorectal cancers, inhibits tumor initiation and progression in the intestine. Here, we demonstrate that ligand-dependent GCC signaling through cGMP induces functional remodeling of cancer cell MMP-9 reflected by a compartmental redistribution of this gelatinase, in which intracellular retention resulted in reciprocal extracellular depletion. Functional remodeling of MMP-9 by GCC signaling reduced the ability of colon cancer cells to degrade matrix components, organize the actin cytoskeleton to form locomotory organelles and spread, and hematogenously seed distant organs. Of significance, GCC effects on cancer cell MMP-9 prevented establishment of metastatic colonies by colorectal cancer cells in the mouse peritoneum in vivo. Since endogenous hormones for GCC are uniformly deficient in intestinal tumors, reactivation of dormant GCC signaling with exogenous administration of GCC agonists may represent a specific intervention to target MMP-9 functions in colon cancer cells. The notion that GCC-mediated regulation of cancer cell MMP-9 disrupts metastasis, in turn, underscores the unexplored utility of GCC hormone replacement therapy in the chemoprevention of colorectal cancer progression.
Cancer Research, 2004
Coagulation has long been known to facilitate metastasis. To pinpoint the steps where coagulation... more Coagulation has long been known to facilitate metastasis. To pinpoint the steps where coagulation might play a role in the metastasis, we used three-dimensional visualization of direct infusion of fluorescence labeled antibody to observe the interaction of tumor cells with platelets and fibrinogen in isolated lung preparations. Tumor cells arrested in the pulmonary vasculature were associated with a clot composed of both platelets and fibrin(ogen). Initially, the cells attached to the pulmonary vessels were rounded. Over the next 2 to 6 hours, they spread on the vessel surface. The associated clot was lysed coincident with tumor cell spreading. To assess the importance of clot formation, we inhibited coagulation with hirudin, a potent inhibitor of thrombin. The number of tumor cells initially arrested in the lung of hirudin-treated mice was essentially the same as in control mice. However, tumor cell spreading and subsequent retention of the tumor cells in the lung was markedly inhibited in the anticoagulated mice. These associations of the tumor cells with platelets were independent of tumor cell expression of P-selectin ligands. This work identifies tumor cell spreading onto the vascular surface as an important component of the metastatic cascade and implicates coagulation in this process.
The American Journal of Pathology, 2002
Supported by the Susan G. Komen Breast Cancer Foundation (grant no. 99-003201 to A. A.) and the N... more Supported by the Susan G. Komen Breast Cancer Foundation (grant no. 99-003201 to A. A.) and the National Cancer Institute (grants RO1 CA-46830 and RO1 CA 89188 to R. J. M.).
Cancer Letters, 2004
The presence of metastases indicates an ominous prognosis in patients with malignancies, yet the ... more The presence of metastases indicates an ominous prognosis in patients with malignancies, yet the factors that distinguish metastatic from non-metastatic tumors remain poorly understood. Here we pursued the hypothesis that apoptosis in vivo would distinguish metastatic cells from non-metastatic cells and developed a novel method for observation of apoptosis induction in living cells. One hour after the infusion of metastatic or non-metastatic human melanoma or transformed rat embryo fibroblasts, arrest of tumor cells in the pulmonary vasculature was equivalent. In order to demonstrate the induction of apoptosis in living cells, we observed the translocation of cytoplasmic BAD-GFP fusion proteins to the mitochondria during apoptosis. Microscopic observation of the tumor cells transfected with BAD-GFP in isolated lung preparations after intravenous injection into nu/nu mice revealed translocation of BAD-GFP in many more of the arrested, non-metastatic melanoma or transformed rat embryo cells over 4-24 h than of the metastatic cells. TUNEL staining confirmed enhanced apoptosis by non-metastatic tumor cells after injection in vivo. Metastatic melanoma cells or metastatic embryo fibroblasts were better able to negotiate the barrier of survival in the circulation after pulmonary arrest than non-metastatic cells confirming the hypothesis that susceptibility to apoptosis after arrest in the pulmonary vasculature distinguishes metastatic from non-metastatic cells and introducing a new assay for in vivo induction of apoptosis.