Limits...
Endothelial-monocyte activating polypeptide II, a novel antitumor cytokine that suppresses primary and metastatic tumor growth and induces apoptosis in growing endothelial cells.

Schwarz MA, Kandel J, Brett J, Li J, Hayward J, Schwarz RE, Chappey O, Wautier JL, Chabot J, Lo Gerfo P, Stern D - J. Exp. Med. (1999)

Bottom Line: Mice implanted with Matrigel showed an intense local angiogenic response, which EMAP II blocked by 76% (P < 0.001).In growing capillary endothelial cultures, EMAP II induced apoptosis in a time- and dose-dependent manner, whereas other cell types were unaffected.These data suggest that EMAP II is a tumor-suppressive mediator with antiangiogenic properties allowing it to target growing endothelium and limit establishment of neovasculature.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, Columbia University, College of Physicians and Surgeons, New York 10032, USA. mschwarz@chla.usc.edu

ABSTRACT
Neovascularization is essential for growth and spread of primary and metastatic tumors. We have identified a novel cytokine, endothelial-monocyte activating polypeptide (EMAP) II, that potently inhibits tumor growth, and appears to have antiangiogenic activity. Mice implanted with Matrigel showed an intense local angiogenic response, which EMAP II blocked by 76% (P < 0.001). Neovascularization of the mouse cornea was similarly prevented by EMAP II (P < 0.003). Intraperitoneally administered EMAP II suppressed the growth of primary Lewis lung carcinomas, with a reduction in tumor volume of 65% versus controls (P < 0.003). Tumors from human breast carcinoma-derived MDA-MB 468 cells were suppressed by >80% in EMAP II-treated animals (P < 0.005). In a lung metastasis model, EMAP II blocked outgrowth of Lewis lung carcinoma macrometastases; total surface metastases were diminished by 65%, and of the 35% metastases present, approximately 80% were inhibited with maximum diameter <2 mm (P < 0.002 vs. controls). In growing capillary endothelial cultures, EMAP II induced apoptosis in a time- and dose-dependent manner, whereas other cell types were unaffected. These data suggest that EMAP II is a tumor-suppressive mediator with antiangiogenic properties allowing it to target growing endothelium and limit establishment of neovasculature.

Show MeSH

Related in: MedlinePlus

Effect of EMAP II on cultured ECs. (A) DNA fragmentation by ELISA of subconfluent cultured bovine capillary ECs in normoxia or hypoxia (pO2 ≈ 14 Torr), exposed to rEMAP II as indicated or heat-inactivated EMAP II (data not shown). (B) The same experiments were performed with subconfluent bovine aortic and venous ECs. (C) The ELISA for DNA fragmentation was performed on LLC, MDA-MB 468, meth A, or vascular SMCs after 24 h of exposure to EMAP II. Data shown represent mean and, in each case, SE was <10%. Experiments with bovine capillary ECs and bovine aortic/venous ECs were repeated three and two times, respectively. (D) ECs exposed to rEMAP II had activation of caspase-3 (lane 2) found in cells undergoing apoptosis compared with control (lane 1).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2195582&req=5

Figure 8: Effect of EMAP II on cultured ECs. (A) DNA fragmentation by ELISA of subconfluent cultured bovine capillary ECs in normoxia or hypoxia (pO2 ≈ 14 Torr), exposed to rEMAP II as indicated or heat-inactivated EMAP II (data not shown). (B) The same experiments were performed with subconfluent bovine aortic and venous ECs. (C) The ELISA for DNA fragmentation was performed on LLC, MDA-MB 468, meth A, or vascular SMCs after 24 h of exposure to EMAP II. Data shown represent mean and, in each case, SE was <10%. Experiments with bovine capillary ECs and bovine aortic/venous ECs were repeated three and two times, respectively. (D) ECs exposed to rEMAP II had activation of caspase-3 (lane 2) found in cells undergoing apoptosis compared with control (lane 1).

Mentions: Our data thus far demonstrated an association of EMAP II with induction of apoptosis in tumors, the latter at least in part in a perivascular distribution. These data suggested the possibility that tumor vasculature might be a target of EMAP II. ELISA for DNA fragmentation was performed to more precisely delineate apoptotic effects of rEMAP II on growing cultured endothelium. There was a dose-dependent increase in DNA fragmentation in cultured bovine capillary endothelium, reaching 250% over that observed in controls within 24 h (Fig. 8 A). As tumor tissue is also known for the presence of areas of local tissue hypoxia/hypoxemia 2627, we assessed whether rEMAP II might display enhanced activity under oxygen deprivation. When cultured subconfluent capillary ECs were exposed to hypoxia (pO2 ≈ 14 Torr), DNA fragmentation was accelerated, reaching a level of 250% above that observed with vehicle alone within 12 h (rather than the 24 h required for an effect of this magnitude in normoxia; Fig. 8 A). This was consistent with the accelerated appearance of apoptotic bodies by 6-diamidine-2-phenylindoledilactate (DAP-1) staining of hypoxic cultured capillary endothelial cultures exposed to rEMAP II. Controls in which bovine capillary ECs were treated with heat-inactivated rEMAP II, in place of active rEMAP II, showed no induction of apoptosis (data not shown). Induction of apoptosis after exposure to rEMAP II was not as striking in cultured bovine aortic or human umbilical venous ECs, where a maximum of ≈50% apoptosis over untreated controls was observed at the highest concentrations of rEMAP II tested (Fig. 8 B; analysis by Student's t test showed no statistical significance). In contrast, LLC or MDA-MB 468 cells, and nontransformed vascular SMCs demonstrated no increase in DNA fragmentation after exposure to rEMAP II under the conditions above by ELISA (Fig. 8 C) or DAP-1 staining (data not shown). Consistent with the observed induction of apoptosis in ECs, we noted that rEMAP II induced activation of the cytosolic protease caspase-3 to its active 17-kD form found in cells undergoing apoptosis (Fig. 8 D).


Endothelial-monocyte activating polypeptide II, a novel antitumor cytokine that suppresses primary and metastatic tumor growth and induces apoptosis in growing endothelial cells.

Schwarz MA, Kandel J, Brett J, Li J, Hayward J, Schwarz RE, Chappey O, Wautier JL, Chabot J, Lo Gerfo P, Stern D - J. Exp. Med. (1999)

Effect of EMAP II on cultured ECs. (A) DNA fragmentation by ELISA of subconfluent cultured bovine capillary ECs in normoxia or hypoxia (pO2 ≈ 14 Torr), exposed to rEMAP II as indicated or heat-inactivated EMAP II (data not shown). (B) The same experiments were performed with subconfluent bovine aortic and venous ECs. (C) The ELISA for DNA fragmentation was performed on LLC, MDA-MB 468, meth A, or vascular SMCs after 24 h of exposure to EMAP II. Data shown represent mean and, in each case, SE was <10%. Experiments with bovine capillary ECs and bovine aortic/venous ECs were repeated three and two times, respectively. (D) ECs exposed to rEMAP II had activation of caspase-3 (lane 2) found in cells undergoing apoptosis compared with control (lane 1).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2195582&req=5

Figure 8: Effect of EMAP II on cultured ECs. (A) DNA fragmentation by ELISA of subconfluent cultured bovine capillary ECs in normoxia or hypoxia (pO2 ≈ 14 Torr), exposed to rEMAP II as indicated or heat-inactivated EMAP II (data not shown). (B) The same experiments were performed with subconfluent bovine aortic and venous ECs. (C) The ELISA for DNA fragmentation was performed on LLC, MDA-MB 468, meth A, or vascular SMCs after 24 h of exposure to EMAP II. Data shown represent mean and, in each case, SE was <10%. Experiments with bovine capillary ECs and bovine aortic/venous ECs were repeated three and two times, respectively. (D) ECs exposed to rEMAP II had activation of caspase-3 (lane 2) found in cells undergoing apoptosis compared with control (lane 1).
Mentions: Our data thus far demonstrated an association of EMAP II with induction of apoptosis in tumors, the latter at least in part in a perivascular distribution. These data suggested the possibility that tumor vasculature might be a target of EMAP II. ELISA for DNA fragmentation was performed to more precisely delineate apoptotic effects of rEMAP II on growing cultured endothelium. There was a dose-dependent increase in DNA fragmentation in cultured bovine capillary endothelium, reaching 250% over that observed in controls within 24 h (Fig. 8 A). As tumor tissue is also known for the presence of areas of local tissue hypoxia/hypoxemia 2627, we assessed whether rEMAP II might display enhanced activity under oxygen deprivation. When cultured subconfluent capillary ECs were exposed to hypoxia (pO2 ≈ 14 Torr), DNA fragmentation was accelerated, reaching a level of 250% above that observed with vehicle alone within 12 h (rather than the 24 h required for an effect of this magnitude in normoxia; Fig. 8 A). This was consistent with the accelerated appearance of apoptotic bodies by 6-diamidine-2-phenylindoledilactate (DAP-1) staining of hypoxic cultured capillary endothelial cultures exposed to rEMAP II. Controls in which bovine capillary ECs were treated with heat-inactivated rEMAP II, in place of active rEMAP II, showed no induction of apoptosis (data not shown). Induction of apoptosis after exposure to rEMAP II was not as striking in cultured bovine aortic or human umbilical venous ECs, where a maximum of ≈50% apoptosis over untreated controls was observed at the highest concentrations of rEMAP II tested (Fig. 8 B; analysis by Student's t test showed no statistical significance). In contrast, LLC or MDA-MB 468 cells, and nontransformed vascular SMCs demonstrated no increase in DNA fragmentation after exposure to rEMAP II under the conditions above by ELISA (Fig. 8 C) or DAP-1 staining (data not shown). Consistent with the observed induction of apoptosis in ECs, we noted that rEMAP II induced activation of the cytosolic protease caspase-3 to its active 17-kD form found in cells undergoing apoptosis (Fig. 8 D).

Bottom Line: Mice implanted with Matrigel showed an intense local angiogenic response, which EMAP II blocked by 76% (P < 0.001).In growing capillary endothelial cultures, EMAP II induced apoptosis in a time- and dose-dependent manner, whereas other cell types were unaffected.These data suggest that EMAP II is a tumor-suppressive mediator with antiangiogenic properties allowing it to target growing endothelium and limit establishment of neovasculature.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, Columbia University, College of Physicians and Surgeons, New York 10032, USA. mschwarz@chla.usc.edu

ABSTRACT
Neovascularization is essential for growth and spread of primary and metastatic tumors. We have identified a novel cytokine, endothelial-monocyte activating polypeptide (EMAP) II, that potently inhibits tumor growth, and appears to have antiangiogenic activity. Mice implanted with Matrigel showed an intense local angiogenic response, which EMAP II blocked by 76% (P < 0.001). Neovascularization of the mouse cornea was similarly prevented by EMAP II (P < 0.003). Intraperitoneally administered EMAP II suppressed the growth of primary Lewis lung carcinomas, with a reduction in tumor volume of 65% versus controls (P < 0.003). Tumors from human breast carcinoma-derived MDA-MB 468 cells were suppressed by >80% in EMAP II-treated animals (P < 0.005). In a lung metastasis model, EMAP II blocked outgrowth of Lewis lung carcinoma macrometastases; total surface metastases were diminished by 65%, and of the 35% metastases present, approximately 80% were inhibited with maximum diameter <2 mm (P < 0.002 vs. controls). In growing capillary endothelial cultures, EMAP II induced apoptosis in a time- and dose-dependent manner, whereas other cell types were unaffected. These data suggest that EMAP II is a tumor-suppressive mediator with antiangiogenic properties allowing it to target growing endothelium and limit establishment of neovasculature.

Show MeSH
Related in: MedlinePlus