Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C1519670 (tumor angiogenesis)
 6,052 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the present study, the type-1 repeats of thrombospondin-1 (TSP-1) were transfected into A431 cells. Expression of all three type-1 repeats (3TSR) and expression of just the second type-1 repeat containing the transforming growth factor (TGF)-beta activating sequence KRFK (TSR2 + KRFK) significantly inhibited in vivo tumor angiogenesis and growth in nude mice. These tumors expressed increased levels of both active and total TGF-beta. A431 cells expressing the second type-1 repeat without the KRFK sequence (TSR2 - KRFK) produced tumors that were slightly larger than the 3TSR and TSR2 + KRFK tumors. These tumors expressed elevated levels of active TGF-beta but levels of total TGF-beta were not different from control tumors. Injection of the peptide, LSKL, which blocks TSP-1 activation of TGF-beta, reversed the growth inhibition observed with cells expressing TSR2 + KRFK to a level comparable to controls. Various residues in the WSHWSPW region and the VTCG sequence of both TSR2+/- KRFK were mutated. Although mutation of the VTCG sequence had no significant effect on tumor growth, mutation of the WSHWSPW sequence reduced inhibition of tumor growth. These findings suggest that the inhibition of tumor angiogenesis and growth by endogenous TSP-1 involves regulation of both active and total TGF-beta and the sequences KRFK and WSHWSPW in the second type-1 repeat.
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PMID:Expression of the type-1 repeats of thrombospondin-1 inhibits tumor growth through activation of transforming growth factor-beta. 1527 28

ADAMTS5 is a member of the A Disintegrin-like And Metalloproteinase with ThromboSpondin motifs (ADAMTS) family of secreted metalloproteinases with multiple proteoglycan substrates. Although well characterized for its role in cartilage degradation and arthritis, how it influences cancer remains unclear. We have previously shown that the first thrombospondin type 1 repeat (TSR1, the central TSR) but not TSR2 (the C-terminal TSR) of ADAMTS5 is anti-angiogenic in vitro. Coupled with previous reports that ADAMTS5 expression is altered in several human cancers, we hypothesized that this proteoglycanase may play an important role in cancer and angiogenesis. Here, we demonstrated that overexpression of full-length ADAMTS5 suppressed B16 melanoma growth in mice. The reduced tumor growth is correlated with diminished tumor angiogenesis, together with reduced tumor cell proliferation and increased tumor cell apoptosis. Catalytically active ADAMTS5 proteolytic fragment also suppressed angiogenesis in vitro. The catalytic activity of ADAMTS5 is dispensable for its anti-tumorigenic function, as the full-length active site mutant E411A presented similar tumor suppression activity. Domain mapping and mechanistic studies revealed that ADAMTS5 inhibits B16 tumorigenesis through its TSR1 by suppressing tumor angiogenesis, likely by down-regulating pro-angiogenic factors such as vascular endothelial growth factor (VEGF), placenta growth factor (PlGF), and platelet-derived endothelial growth factor (PD-ECGF) in the tumor milieu. This is the first report that ADAMTS5 is an anti-angiogenic and anti-tumorigenic protein independent of its proteoglycanase activity.
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PMID:ADAMTS5 functions as an anti-angiogenic and anti-tumorigenic protein independent of its proteoglycanase activity. 2282 41