HER2 Support Group Forums - View Single Post - ER+, HER2+

Jackie07 · 10-16-2008, 07:24 PM

I am not quite sure I understand this, but I thought I would post it for everyone to see. It seems to me that pathway could change, cell nature could change, everything could change...

J Mol Endocrinol. 2008 Sep 3. [Epub ahead of print</SPAN>
Improvement of Sensitivity to Tamoxifen in ER-Positive and Herceptin-Resistant Breast Cancer Cells.
B Chen, Department of Surgical Research, Beckman Research Institute of City of Hope, Duarte, United States.

Her2 overexpression in ER-positive breast cancer cells such as BT474 (BT) cells has been found to confer resistance to tamoxifen, and suppression of Her2 improves the antiproliferative effects of tamoxifen. In this study, the responsiveness to tamoxifen in BT/HerR, Herceptin-resistant BT cell lines established through constant Herceptin exposure, was evaluated. Compared with BT cells, improvement of sensitivity to tamoxifen in BT/HerR was demonstrated by ER functional analysis and cell proliferation assay. Tamoxifen in the resistant cell line was found to inhibit E2-stimulating estrogen-responsive gene pS2 expression more effectively than in BT cells in real time PCR assay. Western analysis showed cross-phosphorylation between ER and downstream components of Her2 was attenuated in BT/HerR cells. ER redistribution from cytoplasm to nucleus could be found in these cells through immunofluorescence and confocal studies and importantly, chromatin immunoprecipitation (ChIP) studies demonstrated that tamoxifen induced occupancy of the pS2 promoter by ER and nuclear receptor corepressor NCoR instead of coactivator AIB1 in these cells. Finally, combination of tamoxifen and Herceptin was found to improve the sensitivity of BT/HerR cells to Herceptin. Our results suggest that the ER genomic pathway in the ER-positive and Herceptin-resistant breast cancer cells may be reactivated, allowing tamoxifen therapy to be effective again, and a combination of tamoxifen and Herceptin can be a potential therapeutic strategy for ER-positive and Herceptin-resistant human breast cancer.
PMID: 18768663 [PubMed - as supplied by publisher]

10-16-2008, 07:24 PM	#23
Jackie07 Senior Member Join Date: Jan 2008 Location: "Love never fails." Posts: 5,808	I am not quite sure I understand this, but I thought I would post it for everyone to see. It seems to me that pathway could change, cell nature could change, everything could change... J Mol Endocrinol. 2008 Sep 3. [Epub ahead of print</SPAN> Improvement of Sensitivity to Tamoxifen in ER-Positive and Herceptin-Resistant Breast Cancer Cells. B Chen, Department of Surgical Research, Beckman Research Institute of City of Hope, Duarte, United States. Her2 overexpression in ER-positive breast cancer cells such as BT474 (BT) cells has been found to confer resistance to tamoxifen, and suppression of Her2 improves the antiproliferative effects of tamoxifen. In this study, the responsiveness to tamoxifen in BT/HerR, Herceptin-resistant BT cell lines established through constant Herceptin exposure, was evaluated. Compared with BT cells, improvement of sensitivity to tamoxifen in BT/HerR was demonstrated by ER functional analysis and cell proliferation assay. Tamoxifen in the resistant cell line was found to inhibit E2-stimulating estrogen-responsive gene pS2 expression more effectively than in BT cells in real time PCR assay. Western analysis showed cross-phosphorylation between ER and downstream components of Her2 was attenuated in BT/HerR cells. ER redistribution from cytoplasm to nucleus could be found in these cells through immunofluorescence and confocal studies and importantly, chromatin immunoprecipitation (ChIP) studies demonstrated that tamoxifen induced occupancy of the pS2 promoter by ER and nuclear receptor corepressor NCoR instead of coactivator AIB1 in these cells. Finally, combination of tamoxifen and Herceptin was found to improve the sensitivity of BT/HerR cells to Herceptin. Our results suggest that the ER genomic pathway in the ER-positive and Herceptin-resistant breast cancer cells may be reactivated, allowing tamoxifen therapy to be effective again, and a combination of tamoxifen and Herceptin can be a potential therapeutic strategy for ER-positive and Herceptin-resistant human breast cancer. PMID: 18768663 [PubMed - as supplied by publisher] __________________ Jackie07 http://www.kevinmd.com/blog/2011/06/doctors-letter-patient-newly-diagnosed-cancer.html http://www.asco.org/ASCOv2/MultiMedi...=114&trackID=2 NICU 4.4 LB Erythema Nodosum 85 Life-long Central Neurocytoma 4x5x6.5 cm 23 hrs 62090 semi-coma 10 d PT OT ST 30 d 3 Infertility tmts 99 > 3 u. fibroids > Pills CN 3 GKRS 52301 IDC 1.2 cm Her2 +++ ER 5% R. Lmptmy SLNB+1 71703 6 FEC 33 R Tamoxifen Recc IIB 2.5 cm Bi-L Mast 61407 2/9 nds PET 6 TCH Cellulitis - Lymphedema - compression sleeve & glove H w x 4 MUGA 51 D, J 49 M Diastasis recti Tamoxifen B. scan Irrtbl bowel 1'09 Colonoscopy 313 BRCA1 V1247I hptc hemangioma Vertigo GI - > yogurt hysterectomy/oophorectomy 011410 Exemestane 25 mg tab 102912 ~ 101016 stopped due to r. hip/l.thigh pain after long walk DEXA 1/13 1-2016 lesions in liver largest 9mm & 1.3 cm onco. says not cancer. 3-11 Appendectomy - visually O.K., a lot of puss. Final path result - not cancer. Start Vitamin D3 and Calcium supplement （600mg x2) 10-10 Stopped Exemestane due to r. hip/l.thigh pain OKed by Onco 11-08-2016 7-23-2018 9 mm groundglass nodule within the right lower lobe with indolent behavior. Due to possible adenocarcinoma, Recommend annual surveilence. 7-10-2019 CT to check lung nodule. 1-10-2020 8mm stable nodule on R Lung, two 6mm new ones on L Lung, a possible lymph node involvement in inter fissule. "I WANT TO BE AN OUTRAGEOUS OLD WOMAN WHO NEVER GETS CALLED AN OLD LADY. I WANT TO GET SHARP EDGED & EARTH COLORED, TILL I FADE AWAY FROM PURE JOY." Irene from Tampa Advocacy is a passion .. not a pastime - Joe Last edited by Jackie07; 10-16-2008 at 07:54 PM..