Abstract:IntroductionTriple-negative breast cancer (TNBC) is aggressive and lacks targeted therapies. Phosphatidylinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathways are frequently activated in TNBC patient tumors at the genome, gene expression and protein levels, and mTOR inhibitors have been shown to inhibit growth in TNBC cell lines. We describe a panel of patient-derived xenografts representing multiple TNBC subtypes and use them to test preclinical drug efficacy of two mTOR inhibitors, sirolimu… Show more
“…PDX are today, with genetically engineered cancer mouse models, a more relevant model because they are based on the graft of fresh primary tumor fragments directly from the patient to immunodeficient mice. PDX maintain the genetic and histologic features of the original tumor (18,26,27). For instance, a good prediction of patient treatment efficacy using PDXs has been reported (28).…”
Purpose: AXL receptor tyrosine kinase has been described as a relevant molecular marker and a key player in invasiveness, especially in triple-negative breast cancer (TNBC).Experimental Design: We evaluate the antitumor efficacy of the anti-AXL monoclonal antibody 20G7-D9 in several TNBC cell xenografts or patient-derived xenograft (PDX) models and decipher the underlying mechanisms. In a dataset of 254 basal-like breast cancer samples, genes correlated with AXL expression are enriched in EMT, migration, and invasion signaling pathways.Results: Treatment with 20G7-D9 inhibited tumor growth and bone metastasis formation in AXL-positive TNBC cell xenografts or PDX, but not in AXL-negative PDX, highlighting AXL role in cancer growth and invasion. In vitro stimulation of AXL-positive cancer cells by its ligand GAS6 induced the expression of several EMT-associated genes (SNAIL, SLUG, and VIM) through an intracellular signaling implicating the transcription factor FRA-1, important in cell invasion and plasticity, and increased their migration/invasion capacity. 20G7-D9 induced AXL degradation and inhibited all AXL/GAS6-dependent cell signaling implicated in EMT and in cell migration/invasion.Conclusions: The anti-AXL antibody 20G7-D9 represents a promising therapeutic strategy in TNBC with mesenchymal features by inhibiting AXL-dependent EMT, tumor growth, and metastasis formation.
“…PDX are today, with genetically engineered cancer mouse models, a more relevant model because they are based on the graft of fresh primary tumor fragments directly from the patient to immunodeficient mice. PDX maintain the genetic and histologic features of the original tumor (18,26,27). For instance, a good prediction of patient treatment efficacy using PDXs has been reported (28).…”
Purpose: AXL receptor tyrosine kinase has been described as a relevant molecular marker and a key player in invasiveness, especially in triple-negative breast cancer (TNBC).Experimental Design: We evaluate the antitumor efficacy of the anti-AXL monoclonal antibody 20G7-D9 in several TNBC cell xenografts or patient-derived xenograft (PDX) models and decipher the underlying mechanisms. In a dataset of 254 basal-like breast cancer samples, genes correlated with AXL expression are enriched in EMT, migration, and invasion signaling pathways.Results: Treatment with 20G7-D9 inhibited tumor growth and bone metastasis formation in AXL-positive TNBC cell xenografts or PDX, but not in AXL-negative PDX, highlighting AXL role in cancer growth and invasion. In vitro stimulation of AXL-positive cancer cells by its ligand GAS6 induced the expression of several EMT-associated genes (SNAIL, SLUG, and VIM) through an intracellular signaling implicating the transcription factor FRA-1, important in cell invasion and plasticity, and increased their migration/invasion capacity. 20G7-D9 induced AXL degradation and inhibited all AXL/GAS6-dependent cell signaling implicated in EMT and in cell migration/invasion.Conclusions: The anti-AXL antibody 20G7-D9 represents a promising therapeutic strategy in TNBC with mesenchymal features by inhibiting AXL-dependent EMT, tumor growth, and metastasis formation.
“…Given the up-regulation of the mTOR pathway in many chemoresistant cancer [2] , mTOR inhibitors provide a logical solution to re-sensitize tumor cells to chemotherapy or to delay the development of resistance to treatment. Recent studies have demonstrated the effectiveness of sirolimus (rapamycin) in solid tumors, such as metastatic breast [3] , pancreatic [4] , and renal carcinomas [5] . Sirolimus is a first generation mTOR inhibitor [6][7][8] .…”
Aim: Multi-drug resistance poses a critical bottleneck in chemotherapy. given the up-regulation of mToR pathway in many chemoresistant cancers, we examined whether sirolimus (rapamycin), a first generation mTOR inhibitor, might induce human osteosarcoma (os) cell apoptosis and increase the sensitivity of os cells to anticancer drugs in vitro. Methods: human os cell line Mg63/aDM was treated with sirolimus alone or in combination with doxorubicin (aDM), gemcitabine (GEM) or methotrexate (MTX). Cell proliferation and apoptosis were detected using CCK-8 assay and flow cytometry, respectively. MiRnas in the cells were analyzed with miRna microarray. The targets of miR-34b were determined based on Targetscan analysis and luciferase reporter assays. The expression of relevant mRna and proteins was measured using qRT-PCR and Western blotting. MiR-34, PaK1 and aBCB1 levels in 40 tissue samples of os patients were analyzed using qRT-PCR and in situ hybridization assays. Results: Sirolimus (1−100 nmol/L) dose-dependently suppressed the cell proliferation (IC 50 =23.97 nmol/L) and induced apoptosis. Sirolimus (10 nmol/L) significantly sensitized the cells to anticancer drugs, leading to decreased IC 50 values of aDM, geM and MTX (from 25.48, 621.41 and 21.72 μmol/L to 4.93, 73.92 and 6.77 μmol/L, respectively). Treatment of with sirolimus increased miR-34b levels by a factor of 7.5 in the cells. upregulation of miR-34b also induced apoptosis and increased the sensitivity of the cells to the anticancer drugs, whereas transfection with miR-34b-aMo, an inhibitor of miR-34b, reversed the anti-proliferation effect of sirolimus. Two key regulators of cell cycle, apoptosis and multiple drug resistance, PaK1 and aBCB1, were demonstrated to be the direct targets of miR-34b. In 40 tissue samples of OS patients, significantly higher miR-34 ISH score and lower PAK5 and ABCB1 scores were detected in the chemo-sensitive group. Conclusion: sirolimus increases the sensitivity of human os cells to anticancer drugs in vitro by up-regulating miR-34b interacting with PaK1 and aBCB1. a low miR-34 level is an indicator of poor prognosis in os patients.
“…5,17,18 Due to dependence on EGFR signaling, many TNBCs also require the mammalian target of rapamycin (mTOR) to mediate proliferation. 17,19 This observation has maintained interest in cytostatic molecules called rapalogues. Like other drugs, rapalogues accumulate in normal tissue, which cause dose-limiting side effects.…”
Recombinant protein–polymer scaffolds such as elastin-like polypeptides (ELPs) offer drug-delivery opportunities including biocompatibility, monodispersity, and multifunctionality. We recently reported that the fusion of FK-506 binding protein 12 (FKBP) to an ELP nanoparticle (FSI) increases rapamycin (Rapa) solubility, suppresses tumor growth in breast cancer xenografts, and reduces side effects observed with free-drug controls. This new report significantly advances this carrier strategy by demonstrating the coassembly of two different ELP diblock copolymers containing drug-loading and tumor-targeting domains. A new ELP nanoparticle (ISR) was synthesized that includes the canonical integrin-targeting ligand (Arg-Gly-Asp, RGD). FSI and ISR mixed in a 1:1 molar ratio coassemble into bifunctional nanoparticles containing both the FKBP domain for Rapa loading and the RGD ligand for integrin binding. Coassembled nanoparticles were evaluated for bifunctionality by performing in vitro cell-binding and drug-retention assays and in vivo MDA-MB-468 breast tumor regression and tumor-accumulation studies. The bifunctional nanoparticle demonstrated superior cell target binding and similar drug retention to FSI; however, it enhanced the formulation potency, such that tumor growth was suppressed at a 3-fold lower dose compared to an untargeted FSI–Rapa control. This data suggests that ELP-mediated scaffolds are useful tools for generating multifunctional nanomedicines with potential activity in cancer.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.