Involvement of the dependence receptor TRKC and its ligand NT-3 in tumorigenesis : from basic research to targeted therapy

Le récepteur à neurotrophine TrkC a été identifié comme étant un récepteur à dépendance : en l'absence de son ligand NT-3, il déclenche l'apoptose. En effet, la survie des cellules qui expriment ces récepteurs dépend de la disponibilité en ligand, un mécanisme qui inhibe la prolifération incontrôlée et la migration des cellules tumorales. TrkC, en tant que récepteur à tyrosine kinase, est généralement considéré comme un proto-oncogène. Or nous montrons que l'expression TrkC est diminuée dans une grande fraction des cancers colorectaux humains, principalement par méthylation du promoteur de TrkC. En outre, ce mécanisme confère un avantage sélectif aux lignées cellulaires colorectales pour inhiber la mort des cellules tumorales. De plus, la réexpression de TrkC dans les lignées tumorales colorectales est associée à la mort des cellules tumorales et à l'inhibition in vitro des caractéristiques de transformation cellulaire, et in vivo de la croissance tumorale. Ensemble, ces données permettent de conclure que TrkC est un gène suppresseur de tumeur dans le cancer colorectal. Le mécanisme moléculaire par lequel TrkC déclenche l'apoptose implique le clivage de son domaine intracellulaire, ce qui libère un fragment pro-apoptotique (TrkC KF). Nous montrons que TrkC KF interagit avec Cobra1, un cofacteur de BRCA1, et que Cobra1 est nécessaire à l'apoptose induite par TrkC. Cobra1 conduit TrkC KF à la mitochondrie, où il favorise l'apoptose apoptosome-dépendante. Ainsi, nous proposons qu'en l'absence de NT-3, le clivage protéolytique de TrkC conduit à la libération d'un fragment tueur qui déclenche l'apoptose mitochondriale, via le recrutement de Cobra1The neurotrophin receptor TrkC was recently identified as a dependence receptor, and, as such, it triggers apoptosis in the absence of its ligand, NT-3. Indeed cells that express these receptors are thought to be dependent on ligand availability for their survival, a mechanism that inhibits uncontrolled tumor cell proliferation and migration. TrkC, as a classic tyrosine kinase receptor, is generally considered to be a proto-oncogene. We show that TrkC expression is down-regulated in a large fraction of human colorectal cancers, mainly through promoter methylation. Moreover, we show that TrkC silencing by promoter methylation is a selective advantage for colorectal cell lines to limit tumor cell death. Furthermore, reestablished TrkC expression in colorectal cancer cell lines is associated with tumor cell death and inhibition of in vitro characteristics of cell transformation, as well as in vivo tumor growth. Together, these data support the conclusion that TrkC is a colorectal cancer tumor suppressor. TrkC triggers apoptosis in the absence of its ligand NT-3 : the molecular mechanism for apoptotic engagement involves the double cleavage of the receptor's intracellular domain, leading to the formation of a proapoptotic fragment (TrkC KF). We show that TrkC KF interfacts with Cobra1, a putative cofactor of BRCA1, and that Cobra1 is required for TrkC-induced apoptosis. Cobra1 shuttles TrkC KF to the mitochondria, where it promotes apoptosome-dependent apoptosis. Thus, we propose that, in the absence of NT-3, the proteolytic cleavage of TrkC leads to the release of a killer fragment that triggers mitochondria-dependent apoptosis via the recruitment of Cobra

Implication du récepteur à dépendance TRKC et de son ligand NT-3 en cancérogénèse : de la recherche fondamentale à la thérapeutique

The neurotrophin receptor TrkC was recently identified as a dependence receptor, and, as such, it triggers apoptosis in the absence of its ligand, NT-3. Indeed cells that express these receptors are thought to be dependent on ligand availability for their survival, a mechanism that inhibits uncontrolled tumor cell proliferation and migration. TrkC, as a classic tyrosine kinase receptor, is generally considered to be a proto-oncogene. We show that TrkC expression is down-regulated in a large fraction of human colorectal cancers, mainly through promoter methylation. Moreover, we show that TrkC silencing by promoter methylation is a selective advantage for colorectal cell lines to limit tumor cell death. Furthermore, reestablished TrkC expression in colorectal cancer cell lines is associated with tumor cell death and inhibition of in vitro characteristics of cell transformation, as well as in vivo tumor growth. Together, these data support the conclusion that TrkC is a colorectal cancer tumor suppressor. TrkC triggers apoptosis in the absence of its ligand NT-3 : the molecular mechanism for apoptotic engagement involves the double cleavage of the receptor's intracellular domain, leading to the formation of a proapoptotic fragment (TrkC KF). We show that TrkC KF interfacts with Cobra1, a putative cofactor of BRCA1, and that Cobra1 is required for TrkC-induced apoptosis. Cobra1 shuttles TrkC KF to the mitochondria, where it promotes apoptosome-dependent apoptosis. Thus, we propose that, in the absence of NT-3, the proteolytic cleavage of TrkC leads to the release of a killer fragment that triggers mitochondria-dependent apoptosis via the recruitment of Cobra1Le récepteur à neurotrophine TrkC a été identifié comme étant un récepteur à dépendance : en l'absence de son ligand NT-3, il déclenche l'apoptose. En effet, la survie des cellules qui expriment ces récepteurs dépend de la disponibilité en ligand, un mécanisme qui inhibe la prolifération incontrôlée et la migration des cellules tumorales. TrkC, en tant que récepteur à tyrosine kinase, est généralement considéré comme un proto-oncogène. Or nous montrons que l'expression TrkC est diminuée dans une grande fraction des cancers colorectaux humains, principalement par méthylation du promoteur de TrkC. En outre, ce mécanisme confère un avantage sélectif aux lignées cellulaires colorectales pour inhiber la mort des cellules tumorales. De plus, la réexpression de TrkC dans les lignées tumorales colorectales est associée à la mort des cellules tumorales et à l'inhibition in vitro des caractéristiques de transformation cellulaire, et in vivo de la croissance tumorale. Ensemble, ces données permettent de conclure que TrkC est un gène suppresseur de tumeur dans le cancer colorectal. Le mécanisme moléculaire par lequel TrkC déclenche l'apoptose implique le clivage de son domaine intracellulaire, ce qui libère un fragment pro-apoptotique (TrkC KF). Nous montrons que TrkC KF interagit avec Cobra1, un cofacteur de BRCA1, et que Cobra1 est nécessaire à l'apoptose induite par TrkC. Cobra1 conduit TrkC KF à la mitochondrie, où il favorise l'apoptose apoptosome-dépendante. Ainsi, nous proposons qu'en l'absence de NT-3, le clivage protéolytique de TrkC conduit à la libération d'un fragment tueur qui déclenche l'apoptose mitochondriale, via le recrutement de Cobra

Analgesic Effects of Topical Amitriptyline in Patients With Chemotherapy-Induced Peripheral Neuropathy: Mechanistic Insights From Studies in Mice

International audienceOral amitriptyline hydrochloride (amitriptyline) is ineffective against some forms of chronic pain and is often associated with dose-limiting adverse events. We evaluated the potential effectiveness of high-dose topical amitriptyline in a preliminary case series of chemotherapy-induced peripheral neuropathy patients and investigated whether local or systemic adverse events associated with the use of amitriptyline were present in these patients. We also investigated the mechanism of action of topically administered amitriptyline in mice. Our case series suggested that topical 10% amitriptyline treatment was associated with pain relief in chemotherapy-induced peripheral neuropathy patients, without the side effects associated with systemic absorption. Topical amitriptyline significantly increased mechanical withdrawal thresholds when applied to the hind paw of mice, and inhibited the firing responses of C-, Aβ- and Aδ-type peripheral nerve fibers in ex vivo skin-saphenous nerve preparations. Whole-cell patch-clamp recordings on cultured sensory neurons revealed that amitriptyline was a potent inhibitor of the main voltage-gated sodium channels (Nav1.7, Nav1.8, and Nav1.9) found in nociceptors. Calcium imaging showed that amitriptyline activated the transient receptor potential cation channel, TRPA1. Our case series indicated that high-dose 10% topical amitriptyline could alleviate neuropathic pain without adverse local or systemic effects. This analgesic action appeared to be mediated through local inhibition of voltage-gated sodium channels. Perspective: Our preliminary case series suggested that topical amitriptyline could provide effective pain relief for chemotherapy-induced peripheral neuropathy patients without any systemic or local adverse events. Investigation of the mechanism of this analgesic action in mice revealed that this activity was mediated through local inhibition of nociceptor Nav channels

Dependence receptor TrkC is a putative colon cancer tumor suppressor

The TrkC neurotrophin receptor belongs to the functional dependence receptor family, members of which share the ability to induce apoptosis in the absence of their ligands. Such a trait has been hypothesized to confer tumor-suppressor activity. Indeed, cells that express these receptors are thought to be dependent on ligand availability for their survival, a mechanism that inhibits uncontrolled tumor cell proliferation and migration. TrkC is a classic tyrosine kinase receptor and therefore generally considered to be a proto-oncogene. We show here that TrkC expression is down-regulated in a large fraction of human colorectal cancers, mainly through promoter methylation. Moreover, we show that TrkC silencing by promoter methylation is a selective advantage for colorectal cell lines to limit tumor cell death. Furthermore, reestablished TrkC expression in colorectal cancer cell lines is associated with tumor cell death and inhibition of in vitro characteristics of cell transformation, as well as in vivo tumor growth. Finally, we provide evidence that a mutation of TrkC detected in a sporadic cancer is a loss-of-proapoptotic function mutation. Together, these data support the conclusion that TrkC is a colorectal cancer tumor suppressor

Dependence receptor TrkC is a putative colon cancer tumor suppressor

The TrkC neurotrophin receptor belongs to the functional dependence receptor family, members of which share the ability to induce apoptosis in the absence of their ligands. Such a trait has been hypothesized to confer tumor-suppressor activity. Indeed, cells that express these receptors are thought to be dependent on ligand availability for their survival, a mechanism that inhibits uncontrolled tumor cell proliferation and migration. TrkC is a classic tyrosine kinase receptor and therefore generally considered to be a proto-oncogene. We show here that TrkC expression is down-regulated in a large fraction of human colorectal cancers, mainly through promoter methylation. Moreover, we show that TrkC silencing by promoter methylation is a selective advantage for colorectal cell lines to limit tumor cell death. Furthermore, reestablished TrkC expression in colorectal cancer cell lines is associated with tumor cell death and inhibition of in vitro characteristics of cell transformation, as well as in vivo tumor growth. Finally, we provide evidence that a mutation of TrkC detected in a sporadic cancer is a loss-of-proapoptotic function mutation. Together, these data support the conclusion that TrkC is a colorectal cancer tumor suppressor

The dependence receptor Trkc triggers mitochondria-dependent apoptosis upon Cobra-1 recruitment

The neurotrophin receptor TrkC was recently identified as a dependence receptor, and, as such, it triggers apoptosis in the absence of its ligand, NT-3. The molecular mechanism for apoptotic engagement involves the double cleavage of the receptor’s intracellular domain, leading to the formation of a proapoptotic “killer” fragment (TrkC KF). Here, we show that TrkC KF interacts with Cobra1, a putative cofactor of BRCA1, and that Cobra1 is required for TrkC-induced apoptosis. We also show that, in the developing chick neural tube, NT-3 silencing is associated with neuroepithelial cell death that is rescued by Cobra1 silencing. Cobra1 shuttles TrkC KF to the mitochondria, where it promotes Bax activation, cytochrome c release, and apoptosome-dependent apoptosis. Thus, we propose that, in the absence of NT-3, the proteolytic cleavage of TrkC leads to the release of a killer fragment that triggers mitochondria-dependent apoptosis via the recruitment of Cobra1

Leiomyosarcoma and liposarcoma in young patients: The national netsarc+ network experience

Background: Leiomyosarcoma (LMS) and liposarcoma (LPS) are ultra-rare sarcomas in pediatric (0–18 years) and young adult (19−30) populations. We aimed to analyze their clinical characteristics at these young ages and to determine whether they should be considered with the same therapeutic strategy in both populations. Methods: National retrospective multicenter study of all young patients (0–30 years) included in the sarcoma database “ConticaBase”, treated for LMS or LPS between 2010 and 2019 via the national NETSARC+ network, with available pathology/biology review. Findings: A total of 218 patients were identified, 34 children (nine LMS, 25 LPS) and 184 young adults (58 LMS, 126 LPS). Myxoid/Round Cell LPS (M/RC-LPS) was the most frequent LPS subtype (72 %). All children had localized LMS and LPS, versus 52/58 and 116/126 respectively in adults. Clinical presentation of LMS and all LPS subtypes was comparable in both populations, except for a preferential limb location of LMS in children. The therapeutic strategy was mainly based on primary surgery in LMS (9/9 children, 52/58 adults) and for LPS (respectively 25/25 and 122/126), exclusively or with adjuvant radiotherapy and systemic treatment. With a median follow-up of 62.4 months (range, 2.5–146), 5-year overall survival was respectively 83 % [95 % CI, 58–100] in children and 73 % [61–88] in young adults for LMS, 100 % [100] vs 92 % [87–99] for M/RC-LPS and 25 % [5–100] vs 60 % [29–100] for pleomorphic LPS. Interpretation: LMS and all LPS subtypes appear to display comparable behavior in children and young adults. The authors propose that the same therapeutic strategy should be considered for both groups