Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0278488 (metastatic breast cancer)
 7,812 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bone is the primary anatomical site of breast cancer metastasis, and bone metastasis is associated with increased morbidity and mortality. Mesenchymal stem cells (MSC) are a predominant fibroblast cell population within the bone marrow, and metastatic breast cancer cells that seed within bone would predictably encounter MSC or their soluble factors. Therefore, we examined the impact of primary human MSC on a panel of estrogen receptor-alpha (ERalpha)-positive (MCF-7, T47D, BT474, and ZR-75-1) and ERalpha-negative (MDA-MB-231 and MDA-MB-468) human breast tumor cell lines. All ERalpha-positive breast tumor cell lines displayed low basal activation of signal transducer and activator of transcription 3 (STAT3) until exposed to MSC, which induced chronic phosphorylation of STAT3 on tyrosine-705. Paracrine IL-6 was found to be the principal mediator of STAT3 phosphorylation in coculture studies, and MSC induction of STAT3 phosphorylation was lost when IL-6 was depleted from MSC conditioned media or the IL-6 receptor was blocked on tumor cells. Enhanced tumor cell growth rates were observed in the ERalpha-positive mammary tumor cell line MCF-7 after paracrine and autocrine IL-6 exposure, where MCF-7 growth rates were enhanced by >2-fold when cocultured with MSC in vitro and even more pronounced in vivo with autocrine IL-6 production.
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PMID:Interleukin-6 is a potent growth factor for ER-alpha-positive human breast cancer. 1758 27

Metastatic breast cancer is an incurable disease, often characterized by poor response to standard chemotherapy, which is mainly based on anthracyclines and taxanes. Thus, increasing tumor cell sensitivity to these agents is an attractive goal towards improving the clinical management of this disease. The present study investigates the effects of signal transducer and activator of transcription 3 (Stat3) inhibition on the response of the highly metastatic MDA-MB-231 human breast adenocarcinoma cell line to doxorubicin (DOX). Stat3 is a transcription factor often constitutively activated in breast tumors and cancer cell lines, and is thought to contribute to malignant transformation and progression by transactivation of a host of target genes involved in cell proliferation and survival, angiogenesis and invasiveness. Our results indicate that (a) untreated MDA-MB-231 cells express higher baseline levels of (activated) pTyr(705)Stat3, that are further upregulated following exposure to DOX, than the non-metastatic MCF-7 cell line; (b) inhibiting the Stat3 signaling pathway, by exposure to the tyrphostin AG490 (an inhibitor of the upstream activating Janus kinases), by transfection with a dominant-negative form of Stat3 or by treatment with satraplatin (a tetravalent platinum derivative that inhibits Stat3 activation), increases breast cancer cell response to the proapoptotic effect of DOX (to different extents). In addition, the latter two approaches have been shown to interfere with expression of one or more antiapoptotic proteins. Overall, these observations suggest that suppression of Stat3 signaling may provide a potential therapeutic approach to overcoming DOX resistance in metastatic breast cancer cells.
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PMID:Inhibition of Stat3 increases doxorubicin sensitivity in a human metastatic breast cancer cell line. 1792 Jul 63

Metastatic breast cancer is a major cause of cancer-related female mortality worldwide. The signal transducer and activator of transcription 3 (STAT3) and the chemokine receptor CXCR4 are involved in the metastatic spread of breast cancer. The goal of this study was to develop nanomedicine treatment based on combined inhibition of STAT3 and CXCR4. We synthesized a library of CXCR4-inhibiting polymers with a combination of beneficial features that included PEGylation, fluorination, and bioreducibility to achieve systemic delivery of siRNA to silence STAT3 expression in the tumors. An in vivo structure-activity relationship study in an experimental lung metastasis model revealed superior antimetastatic activity of bioreducible fluorinated polyplexes when compared with nonreducible controls despite similar CXCR4 antagonism and the ability to inhibit in vitro cancer cell invasion. When compared with nonreducible and nonfluorinated polyplexes, improved siRNA delivery was observed with the bioreducible fluorinated polyplexes. The improvement was ascribed to a combination of enhanced physical stability, decreased serum destabilization, and improved intracellular trafficking. Pharmacokinetic analysis showed that fluorination decreased the rate of renal clearance of the polyplexes and contributed to enhanced accumulation in the tumors. Therapeutic efficacy of the polyplexes with STAT3 siRNA was assessed in early stage breast cancer and late-stage metastatic breast cancer with primary tumor resection. Strong inhibition of the primary tumor growth and pronounced antimetastatic effects were observed in both models of metastatic breast cancer. Mechanistic studies revealed multifaceted mechanism of action of the combined STAT3 and CXCR4 inhibition by the developed polyplexes relying both on local and systemic effects.
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PMID:Reversibly Stabilized Polycation Nanoparticles for Combination Treatment of Early- and Late-Stage Metastatic Breast Cancer. 2998 77

Trastuzumab-emtansine (T-DM1) is an antibody-drug conjugate that has been approved for the treatment of human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer. Despite the remarkable efficacy of T-DM1 in many patients, resistance to this therapeutic has emerged as a significant clinical problem. In the current study, we used BT-474/KR cells, a T-DM1-resistant cell line established from HER2-positive BT-474 breast cancer cells, as a model to investigate mechanisms of T-DM1 resistance and explore effective therapeutic regimens. We show here for the first time that activation of signal transducer and activator of transcription 3 (STAT3) mediated by leukemia inhibitory factor receptor (LIFR) overexpression confers resistance to T-DM1. Moreover, secreted factors induced by activated STAT3 in resistant cells limit the responsiveness of cells that were originally sensitive to T-DM1. Importantly, STAT3 inhibition sensitizes resistant cells to T-DM1, both in vitro and in vivo, suggesting that the combination T-DM1 with STAT3-targeted therapy is a potential treatment for T-DM1-refractory patients.
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PMID:STAT3 activation confers trastuzumab-emtansine (T-DM1) resistance in HER2-positive breast cancer. 3007 57