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dc.contributor.authorHowell, Sacha J
dc.contributor.authorAnderson, Elizabeth
dc.contributor.authorHunter, Tom
dc.contributor.authorFarnie, Gillian
dc.contributor.authorClarke, Robert B
dc.date.accessioned2009-05-22T13:17:54Z
dc.date.available2009-05-22T13:17:54Z
dc.date.issued2008
dc.identifier.citationProlactin receptor antagonism reduces the clonogenic capacity of breast cancer cells and potentiates doxorubicin and paclitaxel cytotoxicity. 2008, 10 (4):R68 Breast Cancer Res.en
dc.identifier.issn1465-542X
dc.identifier.pmid18681966
dc.identifier.doi10.1186/bcr2129
dc.identifier.urihttp://hdl.handle.net/10541/68767
dc.description.abstractINTRODUCTION: Exogenous prolactin is mitogenic and antiapoptotic in breast cancer cells, and overexpression of autocrine prolactin cDNA in breast cancer cell lines has been shown to stimulate their growth and to protect against chemotherapy-induced apoptosis. We examined the effects of the 'pure' prolactin receptor antagonist Delta1-9-G129R-hPrl (Delta1-9) on the breast cancer cell number and clonogenicity, alone and in combination with chemotherapy. METHODS: The effects of doxorubicin, paclitaxel and Delta1-9 on the growth of breast cancer cell lines (MCF-7, T47D, MDA-MB-453, MDA-MB-468 and SK-BR-3) in monolayer culture were assessed by the sulphorhodamine B assay. Effects on clonogenicity were assessed by soft agar assay for the cell lines and by the mammosphere assay for disaggregated primary ductal carcinoma in situ samples. Dual-fluorescence immunocytochemistry was used to identify subpopulations of cells expressing the prolactin receptor and autocrine prolactin. RESULTS: Delta1-9 as a single agent had no effect on the cell number in monolayer culture, but potentiated the cytotoxic effects of doxorubicin and paclitaxel. Doxorubicin accordingly induced expression of prolactin mRNA and protein in all five breast cancer cell lines tested. Delta1-9 alone inhibited the clonogenicity in soft agar of cell lines by ~90% and the mammosphere forming efficiency of six disaggregated primary ductal carcinoma in situ samples by a median of 56% (range 32% to 88%). Subpopulations of cells could be identified in the cell lines based on the prolactin receptor and prolactin expression. CONCLUSION: Autocrine prolactin appears to act as an inducible survival factor in a clonogenic subpopulation of breast cancer cells. The rational combination of cytotoxics and Delta1-9 may therefore improve outcomes in breast cancer therapy by targeting this cell population.
dc.language.isoenen
dc.subjectBreast Canceren
dc.subjectProlactinen
dc.subjectApoptosisen
dc.subject.meshAgar
dc.subject.meshAntineoplastic Agents
dc.subject.meshApoptosis
dc.subject.meshBreast Neoplasms
dc.subject.meshCell Line, Tumor
dc.subject.meshDNA, Complementary
dc.subject.meshDoxorubicin
dc.subject.meshHumans
dc.subject.meshImmunohistochemistry
dc.subject.meshPaclitaxel
dc.subject.meshProlactin
dc.subject.meshRNA, Messenger
dc.subject.meshReceptors, Prolactin
dc.subject.meshReverse Transcriptase Polymerase Chain Reaction
dc.subject.meshRhodamines
dc.titleProlactin receptor antagonism reduces the clonogenic capacity of breast cancer cells and potentiates doxorubicin and paclitaxel cytotoxicity.en
dc.typeArticleen
dc.contributor.departmentBreast Biology Group, Paterson Institute for Cancer Research, University of Manchester, Wilmslow Road, Manchester M20 4BX, UK. SHowell@picr.man.ac.uken
dc.identifier.journalBreast Cancer Researchen
html.description.abstractINTRODUCTION: Exogenous prolactin is mitogenic and antiapoptotic in breast cancer cells, and overexpression of autocrine prolactin cDNA in breast cancer cell lines has been shown to stimulate their growth and to protect against chemotherapy-induced apoptosis. We examined the effects of the 'pure' prolactin receptor antagonist Delta1-9-G129R-hPrl (Delta1-9) on the breast cancer cell number and clonogenicity, alone and in combination with chemotherapy. METHODS: The effects of doxorubicin, paclitaxel and Delta1-9 on the growth of breast cancer cell lines (MCF-7, T47D, MDA-MB-453, MDA-MB-468 and SK-BR-3) in monolayer culture were assessed by the sulphorhodamine B assay. Effects on clonogenicity were assessed by soft agar assay for the cell lines and by the mammosphere assay for disaggregated primary ductal carcinoma in situ samples. Dual-fluorescence immunocytochemistry was used to identify subpopulations of cells expressing the prolactin receptor and autocrine prolactin. RESULTS: Delta1-9 as a single agent had no effect on the cell number in monolayer culture, but potentiated the cytotoxic effects of doxorubicin and paclitaxel. Doxorubicin accordingly induced expression of prolactin mRNA and protein in all five breast cancer cell lines tested. Delta1-9 alone inhibited the clonogenicity in soft agar of cell lines by ~90% and the mammosphere forming efficiency of six disaggregated primary ductal carcinoma in situ samples by a median of 56% (range 32% to 88%). Subpopulations of cells could be identified in the cell lines based on the prolactin receptor and prolactin expression. CONCLUSION: Autocrine prolactin appears to act as an inducible survival factor in a clonogenic subpopulation of breast cancer cells. The rational combination of cytotoxics and Delta1-9 may therefore improve outcomes in breast cancer therapy by targeting this cell population.


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