Linked Life Data

2696842

Source:http://linkedlifedata.com/resource/pubmed/id/2696842

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-6
pubmed:dateCreated
1990-3-30
pubmed:abstractText
Progression from steroid sensitive to autonomous proliferation can be modelled in several cultured mammary tumour cell lines by long-term withdrawal of steroids. A feature of all the four systems studied thus far is that the basal growth in the absence of steroid increases with duration of steroid withdrawal until it reaches that obtained in the presence of steroid. It cannot be assumed that the increased proliferation in the absence of steroid is modulated by the same pathways as those stimulated by steroids in sensitive cells. Therefore, we feel that mechanisms of progression can best be studied via cell behaviour in the absence of steroid. With both the mouse S115 and human T-47-D systems, changes in sensitivity to several growth factors accompany progression; responses to TGF beta 1 are of particular interest in the T-47-D cells where this growth factor becomes stimulatory in the steroid insensitive state. This is accompanied by upregulation of TGF beta 1 mRNA. This upregulation of TGF beta agrees with the finding that ER - PR - primary human breast tumours contain more TGF beta 1 than do ER + PR + tumours; TGF alpha has the opposite pattern. Furthermore, only 40 and 30 kDa TGF beta species have been detected within cultured cells and primary tumours; TGF alpha exists in a 30 kDa form. The functions of these large forms of TGF alpha and TGF beta are unclear. Our conclusions from these experiments is that the increased proliferation in the absence of steroid accompanying progression may not be mediated by the same pathways as those perturbed by steroids in sensitive cells. Furthermore, TGF beta 1 may have different effects in steroid responsive and unresponsive cells.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0022-4731
pubmed:author
pubmed:issnType
Print
pubmed:volume
34
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
133-8
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Approaches to studying the role of growth factors in the progression of breast tumours from the steroid sensitive to insensitive state.
pubmed:affiliation
Hormone Biochemistry, Laboratory Imperial Cancer Rssearch Fund, London, U.K.
pubmed:publicationType
Journal Article, Review