Endocrine Abstracts

IntroductionIncreased cross talk between the IGF-I and oestrogen signalling pathways has been implicated in the development of tamoxifen resistance in breast cancers. We have previously demonstrated IGF-I mRNA to be down-regulated in primary breast cancers. However, the expression of IGF-I and IGFBP-3 in recurrent, tamoxifen-resistant tumours is unknown.MethodsTotal RNA was extracted from 38 paired samples of...

IntroductionIncreased cross talk between the IGF-I and oestrogen signalling pathways has been implicated in the development of tamoxifen resistance in breast cancers. We have previously demonstrated IGF-I mRNA to be down-regulated in primary breast cancers. However, the expression of IGF-I and IGFBP-3 in recurrent, tamoxifen-resistant tumours is unknown.MethodsTotal RNA was extracted from 38 paired samples of primary breast cancers (T) and adjacent normal (N) tissue and from 1...

Background: Tamoxifen is a partial estrogen agonist used to treat estrogen receptor positive breast cancer. It has been discovered however that resistance to tamoxifen develops in some cancers. In order to investigate the mechanisms underlying the development of resistance we have created a tamoxifen resistant breast cancer cell line.Aims: To develop a breast cancer cell line that is resistant to the anti-growth effects of tamoxifen.<p class="abstext...

Introduction: The GH/IGF-I axis has been implicated in the pathogenesis of breast cancer and development of tamoxifen resistance. We have previously used siRNA to successfully silence the IGF-I receptor (IGF-IR) in MCF-7 breast cancer cells. To further characterize the growth changes that occur when elements of the GH/IGF-I axis are disrupted we investigated the use of siRNA to cause long term silencing of IGF-IR.Methods: MCF-7 cells were cultured in phe...

Background: Previous studies have implicated the GH/IGF-I axis in the pathogenesis of breast cancer and the development of tamoxifen resistance. IGF-I is a known proliferative and anti-apoptotic agent. In order to characterize the growth changes that occur when elements of the GH/IGF-I axis are disrupted we have used siRNA to transcriptionally silence the IGF-IR in the MCF-7 human breast cancer cell line.Methods: MCF-7 cells were cultured in phenol red-f...

Background: Serum IGF-I and IGFBP-3 levels respectively have a positive and negative association with subsequent risk of breast cancer. The anti-oestrogen tamoxifen is widely used as adjunctive therapy after resection of primary breast tumours. Tamoxifen has been reported to influence serum IGF-I, although its effects on BP-3 are unknown. The effects of tumour resection itself on IGF-I and BP-3 levels are unclear.Aims: To determine the effects of surgery...