Direct interaction of TrkA/CD44v3 is essential for NGF-promoted aggressiveness of breast cancer cells

Background CD44 is a multifunctional membrane glycoprotein. Through its heparan sulfate chain, CD44 presents growth factors to their receptors. We have shown that CD44 and Tropomyosin kinase A (TrkA) form a complex following nerve growth factor (NGF) induction. Our study aimed to understand how CD44 and TrkA interact and the consequences of inhibiting this interaction regarding the pro-tumoral effect of NGF in breast cancer. Methods After determining which CD44 isoforms (variants) are involved in forming the TrkA/CD44 complex using proximity ligation assays, we investigated the molecular determinants of this interaction. By molecular modeling, we isolated the amino acids involved and confirmed their involvement using mutations. A CD44v3 mimetic peptide was then synthesized to block the TrkA/CD44v3 interaction. The effects of this peptide on the growth, migration and invasion of xenografted triple-negative breast cancer cells were assessed. Finally, we investigated the correlations between the expression of the TrkA/CD44v3 complex in tumors and histo-pronostic parameters. Results We demonstrated that isoform v3 (CD44v3), but not v6, binds to TrkA in response to NGF stimulation. The final 10 amino acids of exon v3 and the TrkA H112 residue are necessary for the association of CD44v3 with TrkA. Functionally, the CD44v3 mimetic peptide impairs not only NGF-induced RhoA activation, clonogenicity, and migration/invasion of breast cancer cells in vitro but also tumor growth and metastasis in a xenograft mouse model. We also detected TrkA/CD44v3 only in cancerous cells, not in normal adjacent tissues. Conclusion Collectively, our results suggest that blocking the CD44v3/TrkA interaction can be a new therapeutic option for triple-negative breast cancers

Etude de la signalisation du proNGF dans les cellules de cancer du sein

Le NGF (Nerve Growth Factor) induit la croissance des cellules cancéreuses de sein, alors qu il est sans effet sur les cellules normales. Il participe également au développement tumoral in vivo et est une cible thérapeutique potentielle dans le cancer du sein. Le NGF agit via les récepteurs TrkA et p75NTR. De même, le précurseur du NGF, le proNGF, peut être sécrété et induire la mort neuronale en se liant à p75NTR et à la sortiline. Néanmoins, aucune donnée n a été rapportée sur l expression et les effets potentiels du proNGF dans le cancer du sein. Au cours de ma thèse, nous avons démontré que le proNGF est produit et sécrété par les cellules cancéreuses de sein. Nous avons observé une surproduction du proNGF dans les biopsies cancéreuses malignes par rapport aux biopsies normales et aux pathologies bénignes. Cette surexpression est associée à l envahissement des nœuds lymphatiques.J ai confirmé, in vitro, que le proNGF, comme le NGF, favorise l invasion des cellules cancéreuses de sein. Néanmoins, ces effets sont induits via des voies de signalisation distinctes. Ainsi, j ai montré le rôle essentiel de la sortiline dans l effet pro-invasif du proNGF. De même, le proNGF, comme le NGF, est capable d activer la phosphorylation de TrkA mais ceci conduit à des voies de transduction différentes. Une analyse de l interactome de TrkA a permis d identifier des protéines différentiellement recrutées en fonction du ligand. Ainsi, l ensemble des résultats obtenus a permis de mettre en évidence l intervention du proNGF dans le cancer du sein. La discrimination des voies induites par le proNGF et par le NGF offre la possibilité de nouvelles modulations thérapeutiques dans ce cancer.Nerve Growth Factor (NGF) induces the growth of breast cancer cells, whereas it has no effect on normal breast epithelial cells. NGF acts also on the tumor development in vivo and is considered as a potential therapeutic target in breast cancer. To exert its effects, NGF binds the receptors TrkA and p75NTR. More recently, proNGF, the NGF precursor, has been found to be secreted and to induce neuronal cell death by binding to a sortilin/p75NTR complex. Nevertheless, so far no data has been reported on the expression and the putative effects of proNGF in breast cancer cells. During my thesis, we have demonstrated that proNGF is produced and secreted by breast cancer cells. Moreover, we revealed an overproduction of proNGF in malignant breast tumors, in comparison to benign tumors and normal biopsies. Interestingly, a statistically significant association was obtained between the presence of proNGF and lymph node invasion by breast cancer cells. I confirmed that proNGF, but also NGF, induces in vitro breast cancer cell invasion. However, both proNGF and NGF induce their effects through distinct signaling pathways. I found that sortilin is essential for the proNGF pro-invasive effect while p75NTR is not necessary. Interestingly, proNGF, like NGF, is able to activate TrkA phosphorylation but this leads to different transduction cascades. TrkA interactome analysis allowed the identification of proteins differentially recruited on the receptor, depending on the ligand. Thus, our results demonstrate the first implication of proNGF in breast cancer. Deciphering of the pathways induced by proNGF and NGF would give the opportunity for new therapeutic modulations in breast cancer.LILLE1-Bib. Electronique (590099901) / SudocSudocFranceF

Ciblage du récepteur aux facteurs de croissance épithé liaux (REGF) par les inhibiteurs de tyrosine kinase et applications dans les cancers colorectaux

EGF receptor is moderately overexpressed in colorectal cancer and it is globally associated to poor prognosis outcome. Thus determination of EGFR level represents a major interest in order to orientate a targeted therapy and to redefine a new prognostic biological marker to treat colorectal cancer patients. In vitro studies conduced with tyrosine kinase inhibitors in colorectal cancer cell lines have demonstrated additive effects with conventional treatment and molecular biology could explained these positive interactions. Basis on these preclinical studies, future large clinical trials could create a real hope for all patients presenting a colorectal cancer.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

TrkA Co-Receptors: The Janus Face of TrkA?

Larotrectinib and Entrectinib are specific pan-Trk tyrosine kinase inhibitors (TKIs) approved by the Food and Drug Administration (FDA) in 2018 for cancers with an NTRK fusion. Despite initial enthusiasm for these compounds, the French agency (HAS) recently reported their lack of efficacy. In addition, primary and secondary resistance to these TKIs has been observed in the absence of other mutations in cancers with an NTRK fusion. Furthermore, when TrkA is overexpressed, it promotes ligand-independent activation, bypassing the TKI. All of these clinical and experimental observations show that genetics does not explain all therapeutic failures. It is therefore necessary to explore new hypotheses to explain these failures. This review summarizes the current status of therapeutic strategies with TrkA inhibitors, focusing on the mechanisms potentially involved in these failures and more specifically on the role of TrkA

Stable 'portrait' of breast tumors during progression: Data from biology, pathology and genetics

SCOPUS: re.jinfo:eu-repo/semantics/publishe

p53 and breast cancer, an update

SCOPUS: re.jinfo:eu-repo/semantics/publishe

Concurrent hormone and radiation therapy in patients with breast cancer: what is the rationale?

Endocrine therapy is often given together with postoperative radiotherapy in patients with breast cancer and positive hormone-receptor status. However, few experimental or clinical studies address the combined effects of hormone and radiation therapy. Preclinical models have shown changes in tumour cell kinetics with the addition of tamoxifen, and some show reduced tumour cell death with concurrent anti-oestrogen treatment and radiotherapy. Although data from in-vitro studies support the notion of antagonistic effects of concurrent tamoxifen and radiotherapy on tumour cells, in-vivo research suggests a synergistic effect that could be attributable to micro-environmental changes in tumour responsiveness to ionising radiation and hormone therapy. Retrospective studies suggest that in practical application, concurrent administration of tamoxifen with radiotherapy does not compromise local control but might increase toxicity. Preliminary results from simultaneous treatment with aromatase inhibitors and radiation indicate that this combination of endocrine and radiation therapy could enhance cytotoxicity and improve tumour response. Further studies are needed to clarify the physiological mechanisms activated by oestrogens, which will allow a more thorough understanding of the complex interactions between 17beta-oestradiol and P53/P21WAF1/CIP1/Rb pathways and of the interaction between endocrine therapy and radiotherapy. © 2009 Elsevier Ltd. All rights reserved.SCOPUS: re.jinfo:eu-repo/semantics/publishe

Antiproliferative and apoptotic effects of the oxidative dimerization product of methyl caffeate on human breast cancer cells

Caffeic acid derivatives are increasingly regarded as potential oncoprotective that could inhibit both the initiation and progression of cancer. Here we have synthesized seven 1-arylnaphthalene lignans and related compounds and tested their impact on breast cancer cell growth in tissue culture. The product of the oxidative dimerization of methyl caffeate, 1-phenylnaphthalene lignan, was found to induce a strong decrease in breast cancer cell number (IC₅₀ ∼1 μM) and was selected for further investigation. Flow cytometry analysis revealed a decrease in cell proliferation and an increase in apoptosis in both MCF-7 and MDA-MB-231 breast cancer cell lines that are representative of the two main categories of breast tumors. The 3,4-dihydroxyphenyl group probably induced the biological activity, as the control compounds lacking it had no effect on breast cancer cells. Together, our data indicate that the oxidative dimerization product of methyl caffeate can inhibit breast cancer cell growth at a concentration adequate for pharmacological use

Biomodulation du facteur de transcription NF-κB par les radiations ionisantes

NF-κB (Nuclear Factor -κB) was described for the first time in 1986 as a nuclear protein binding to the kappa immunoglobulin-light chain enhancer. Since then, NF-κB has emerged as an ubiquitous factor involved in the regulation of numerous important processes as diverse as immune and inflammatory responses, apoptosis and cell proliferation. These last two properties explain the implication of NF-κB in the tumorigenic process as well as the promise of a targeted therapeutic intervention. This review focuses on the current knowledge on NF-κB regulation and discusses the therapeutic potential of targeting NF-κB in cancer in particular during radiotherapy. © 2004 Elsevier SAS. Tous droits réservés.SCOPUS: re.jinfo:eu-repo/semantics/publishe