The anti-leukemic drug nilotinib inhibits invasive and metastatic properties of colorectal cancer cells by targeting the collagen receptor DDR1.

Le cancer colorectal (CCR) demeure l'une des principales causes de décès par cancer dans le monde. Récemment, une nouvelle immunothérapie basée sur le ciblage du récepteur à activité tyrosine kinase (RTK) EGFR via l'anticorps cetuximab a montré une amélioration significative de la survie des patients atteints de CCR métastatique (CCRm). Cependant, une grande partie de ces patients présente une résistance qui est associée à la présence de mutations gains de fonction dans la voie de signalisation Ras. Dans ce contexte, l'identification de cibles thérapeutiques Ras-indépendantes pourrait avoir un intérêt particulier. Une analyse pharmacologique effectuée au laboratoire démontre que le nilotinib, un inhibiteur de la TK oncogénique BCR-ABL utilisée en clinique pour le traitement des leucémies myéloïdes chroniques, affecte également les propriétés invasives et métastatiques de cellules de CCR. Nous avons identifié la cible majoritaire de cet inhibiteur dans cette réponse tumorale : il s'agit de DDR1, un récepteur au collagène ayant une activité TK intrinsèque. Mon travail de thèse a mis en évidence que DDR1 est fréquemment et fortement activé dans les métastases de patients atteints de CCR. J'ai ensuite analysé la signalisation DDR1-dépendante dans ces cellules tumorales par phosphoprotéomique quantitative. Cette analyse montre la nature Ras-indépendante de cette signalisation et révèle la protéine de signalisation BCR comme un nouveau substrat essentiel de DDR1 pour induire l'invasion cellulaire. Enfin, je montre que l'inhibition de DDR1 par le nilotinib améliore la réponse au cetuximab y compris pour les cellules tumorales ayant une mutation oncogénique de K-Ras ou B-Raf. En conclusion, ces résultats suggèrent que le ciblage de DDR1 par le nilotinib pourrait avoir un intérêt thérapeutique dans le traitement des CCRm.Colorectal cancer (CRC) is one of the leading causes of cancer-related death in the Western world. Cancer that metastasizes to distant sites is usually not curable, although chemotherapy can extend survival. Recently, a novel immunotherapy approach based on targeting the EGFR tyrosine kinase (TK) via the antibody cetuximab was shown to significantly improve the survival of patients with metastatic CRC (mCRC). However, only patients with wild-type KRAS may hope to gain from EGFR inhibition. The majority of patients expresses oncogenic K-Ras alleles and thus have hyperactive Ras cascade operating independently from EGFR. Therefore, there is an urgent need for discovery of a new Ras-independent target that regulates tumor cell invasion and metastasis in mCRC. A pharmacological approach in the lab revealed that the small inhibitor of the leukemic TK BCR-Abl also inhibits invasive and metastatic abilities of CRC cells. This effect was also observed in cells expressing deregulated KRAS signalling. We next identified the receptor for collagen and atypical TK DDR1 as that the main target of nilotinib in these cells. Accordingly, DDR1 was found frequently and strongly activated in metastatic nodules of CRC patients. I also characterized DDR1 signalling by quantitative phosphoproteomic. This analysis revealed the Ras-independent nature of DDR1 signalling but also the Rho GTPase regulator BCR as an essential DDR1 substrate that leads to cell invasion. Finally, I demonstrate that nilotinib potentiates cetuximab response in CRC cells expressing oncogenic K-Ras signaling. Overall, these results suggest that the targeting of DDR1 by nilotinib may be of therapeutic value in mCRC

Validation of a high performance functional assay for individual radiosensitivity in pediatric oncology: a prospective cohort study (ARPEGE)

Abstract Background Approximately 900 children/adolescents are treated with radiotherapy (RT) every year in France. However, among the 80% of survivors, the cumulative incidence of long-term morbidity – including second malignancies - reach 73.4% thirty years after the cancer diagnosis. Identifying a priori the subjects at risk for RT sequelae is a major challenge of paediatric oncology. Individual radiosensitivity (IRS) of children/adolescents is unknown at this time, probably with large variability depending on the age when considering the changes in metabolic functions throughout growth. We previously retrospectively showed that unrepaired DNA double strand breaks (DSB) as well a delay in the nucleoshuttling of the pATM protein were common features to patients with RT toxicity. We aim to validate a high performance functional assay for IRS prospectively. Methods/design ARPEGE is a prospective open-label, non-randomized multicentre cohort study. We will prospectively recruit 222 children/adolescents who require RT as part of their routine care and follow them during 15 years. Prior RT we will collect blood and skin samples to raise a primary dermal fibroblast line to carry out in blind the IRS assay. As a primary objective, we will determine its discriminating ability to predict the occurrence of unusual early skin, mucous or hematological toxicity. The primary endpoint is the measurement of residual double-strand breaks 24 h after ex vivo radiation assessed with indirect immunofluorescence (γH2AX marker). Secondary endpoints include the determination of pATM foci at 10 min and 1 h (pATM marker) and micronuclei at 24 h. In parallel toxicity including second malignancies will be reported according to NCI-CTCAE v4.0 reference scale three months of the completion of RT then periodically during 15 years. Confusion factors such as irradiated volume, skin phototype, previous chemotherapy regimen, smoking, comorbities (diabetes, immunodeficiency, chronic inflammatory disease...) will be reported. Discussion ARPEGE would be the first study to document the distribution of IRS in the pediatric subpopulation. Screening hypersensitive patients would be a major step forward in the management of cancers, opening a way to personalized pediatric oncology. Trial registration ID-RCB number: 2015-A00975–44, ClinicalTrials.gov Identifier: NCT02827552 Registered 7/6/2016

Inhibition of DDR1‐BCR signalling by nilotinib as a new therapeutic strategy for metastatic colorectal cancer

Abstract The clinical management of metastatic colorectal cancer (mCRC) faces major challenges. Here, we show that nilotinib, a clinically approved drug for chronic myeloid leukaemia, strongly inhibits human CRC cell invasion in vitro and reduces their metastatic potential in intrasplenic tumour mouse models. Nilotinib acts by inhibiting the kinase activity of DDR1, a receptor tyrosine kinase for collagens, which we identified as a RAS‐independent inducer of CRC metastasis. Using quantitative phosphoproteomics, we identified BCR as a new DDR1 substrate and demonstrated that nilotinib prevents DDR1‐mediated BCR phosphorylation on Tyr177, which is important for maintaining β‐catenin transcriptional activity necessary for tumour cell invasion. DDR1 kinase inhibition also reduced the invasion of patient‐derived metastatic and circulating CRC cell lines. Collectively, our results indicate that the targeting DDR1 kinase activity with nilotinib may be beneficial for patients with mCRC