Bone sialoprotein in bone development, osteogenesis, and angiogenesis : regulatory interplay with osteopontin

Les "Small Integrin Binding Ligand N-Linked Glycoproteins" constituent un groupe de protéines matricellulaires fortement impliquées dans la formation et la minéralisation osseuse, et qui inclut la Sialoprotéine Osseuse (BSP) et l’Ostéopontine (OPN). Le phénotype des souris BSP-/- montre qu’elles sont dès la naissance plus petite, avec des os longs plus courts à l’âge adulte. L’analyse de leur développement s’est trouvée compliquée par un trouble comportemental des femelles BSP-/- qui ne forment pas de nid. Les croisements entre les souris-/-, +/+ et +/- ont établi que le phénotype osseux de ces souris est d’origine purement génétique. Le taux circulant d’OPN plus élevé chez ces souris suggère une compensation de l’absence de la BSP par l’OPN. Dans un modèle d’injection de PTH sur la moitié droite de l’os pariétal que nous avons développé, la PTH induit localement une augmentation des paramètres histologiques, microtomographiques et moléculaires de formation osseuse dans les deux génotypes. L’injection in vivo de siARN bloquant l’expression d’OPN ne change pas l’effet anabolique de la PTH chez les souris BSP+/+, mais bloque cet effet chez les souris BSP-/-. Ces résultats suggèrent que l’OPN pourrait remplacer la BSP dans certaines de ses fonctions. Le modèle d’ablation médullaire permet d’analyser sur un temps court la revascularisation du conduit osseux. Trois jours après l’ablation l’os des souris BSP-/- présentait une densité vasculaire plus élevée que les BSP+/+, associée à une expression élevée d’OPN et de VEGF, suggérant l’intervention de l’un ou de ces deux facteurs dans la stimulation de l’angiogenèse. En conclusion, l’absence de BSP affecte l’interaction entre l’ostéogenèse, l’angiogenèseThe Small Integrin Binding Ligand N-Linked Glycoproteins family is involved in bone formation and angiogenesis, and it includes bone sialoprotein (BSP) and osteopontin (OPN). Our laboratory has characterized the phenotype of BSP-/- mice, which have a hypomineralised skeleton and are smaller presenting shorter long bone in adulthood. The analysis of their development has been complicated by a behavioral disorder of female BSP-/-, which do not form a nest after parturition. We performed a series of crossfoster breedings, which established that the bone phenotype of BSP-/- is of purely genetic origin. After birth, BSP-/- pups showed higher circulating level of OPN, which suggests a compensation of the lack of BSP by OPN. We developed a model of intermittent injection of PTH over the periosteum of the right mouse hemicalvaria to test the latter hypothesis. PTH induced a local increase of histological microtomographic and molecular bone formation parameters in both genotypes. The Inhibition of this protein by injection of siRNA did not change the anabolic effect of PTH in wild mice, in contrast, this anabolic effect was blocked in BSP-/- mice. These results suggest that OPN could replace BSP in some of its functions. Knowing that OPN is overexpressed in the absence of BSP and is highly angiogenic, we used a model of bone marrow ablation to analyze the revascularization of bone shaft. Three days after ablation BSP-/- femurs showed higher vessel density with higher expression of OPN and VEGF suggesting the involvement of one or both of these factors in the stimulation of angiogenesis. In conclusion, the absence of BSP affects the interplay between osteogenesis, angiogenesi

La sialoprotéine osseuse dans le développement osseux, l'ostéogenèse et l'angiogenèse : régulations croisées avec l'ostéopontine

The Small Integrin Binding Ligand N-Linked Glycoproteins family is involved in bone formation and angiogenesis, and it includes bone sialoprotein (BSP) and osteopontin (OPN). Our laboratory has characterized the phenotype of BSP-/- mice, which have a hypomineralised skeleton and are smaller presenting shorter long bone in adulthood. The analysis of their development has been complicated by a behavioral disorder of female BSP-/-, which do not form a nest after parturition. We performed a series of crossfoster breedings, which established that the bone phenotype of BSP-/- is of purely genetic origin. After birth, BSP-/- pups showed higher circulating level of OPN, which suggests a compensation of the lack of BSP by OPN. We developed a model of intermittent injection of PTH over the periosteum of the right mouse hemicalvaria to test the latter hypothesis. PTH induced a local increase of histological microtomographic and molecular bone formation parameters in both genotypes. The Inhibition of this protein by injection of siRNA did not change the anabolic effect of PTH in wild mice, in contrast, this anabolic effect was blocked in BSP-/- mice. These results suggest that OPN could replace BSP in some of its functions. Knowing that OPN is overexpressed in the absence of BSP and is highly angiogenic, we used a model of bone marrow ablation to analyze the revascularization of bone shaft. Three days after ablation BSP-/- femurs showed higher vessel density with higher expression of OPN and VEGF suggesting the involvement of one or both of these factors in the stimulation of angiogenesis. In conclusion, the absence of BSP affects the interplay between osteogenesis, angiogenesisLes "Small Integrin Binding Ligand N-Linked Glycoproteins" constituent un groupe de protéines matricellulaires fortement impliquées dans la formation et la minéralisation osseuse, et qui inclut la Sialoprotéine Osseuse (BSP) et l’Ostéopontine (OPN). Le phénotype des souris BSP-/- montre qu’elles sont dès la naissance plus petite, avec des os longs plus courts à l’âge adulte. L’analyse de leur développement s’est trouvée compliquée par un trouble comportemental des femelles BSP-/- qui ne forment pas de nid. Les croisements entre les souris-/-, +/+ et +/- ont établi que le phénotype osseux de ces souris est d’origine purement génétique. Le taux circulant d’OPN plus élevé chez ces souris suggère une compensation de l’absence de la BSP par l’OPN. Dans un modèle d’injection de PTH sur la moitié droite de l’os pariétal que nous avons développé, la PTH induit localement une augmentation des paramètres histologiques, microtomographiques et moléculaires de formation osseuse dans les deux génotypes. L’injection in vivo de siARN bloquant l’expression d’OPN ne change pas l’effet anabolique de la PTH chez les souris BSP+/+, mais bloque cet effet chez les souris BSP-/-. Ces résultats suggèrent que l’OPN pourrait remplacer la BSP dans certaines de ses fonctions. Le modèle d’ablation médullaire permet d’analyser sur un temps court la revascularisation du conduit osseux. Trois jours après l’ablation l’os des souris BSP-/- présentait une densité vasculaire plus élevée que les BSP+/+, associée à une expression élevée d’OPN et de VEGF, suggérant l’intervention de l’un ou de ces deux facteurs dans la stimulation de l’angiogenèse. En conclusion, l’absence de BSP affecte l’interaction entre l’ostéogenèse, l’angiogenès

Cardio-Oncology Preclinical Models: A Comprehensive Review

International audienceCardiotoxicity is a common side effect induced by cancer therapies, which increases the risk of long-term morbidity and mortality in cancer survivors. To date, the mechanism leading to this toxicity is still unclear, thus complicating cardiac safety assessment and predictive factor identification. The advances in technology, particularly regarding radiation therapy and constant development of novel antineoplastic agents, require urgent development of efficient preclinical models to detect drug cardiotoxicity. A myriad of empirical preclinical models have been used to investigate cardiotoxicity, though with limited success. Recently, multicellular spheroid models have gained attention by mimicking the in vivo microenvironment. The aim of this review is to focus on the most relevant preclinical models used to assess antineoplastic drug- and radiotherapy-related cardiotoxicities, with an overview on their current use. It also aims to discuss the possible directions of translational research in the cardio-oncology field

Challenges in radiobiology – technology duality as a key for a risk-free α/β ratio

International audienceSince radiotherapy discovery, prediction of biological response to ionizing radiation remains a major challenge. Indeed, several radiobiological models appeared through radiotherapy history. Nominal single dose so popular in the 1970s, was tragically linked to the dark years in radiobiology by underestimating the late toxicity of the high-dose fractions. The actual prominent linear-quadratic model continues to prove to be an effective tool in radiobiology. Mainly with its pivotal α/β ratio, which gives a reliable estimate of tissues sensitivity to fractions. Despite these arguments, this model experiences limitations with substantial doubts of α/β ratio values. Interestingly, the story of radiobiology since X-ray discovery is truly instructive and teaches modern clinicians to refine fractionation schemes. Many fractionation schemes have been tested with successes or dramas. This review retraces radiobiological models’ history, and confronts these models to new fractionation schemes, drawing a preventive message

How to improve clinical research in a department of radiation oncology

International audienceIntroductionRadiation therapy is a core modality for cancer treatment. Around 40% of cancer cures include the use of radiotherapy, either as a single strategy or combined with other treatments. In the past decade, substantial technical advances and novel insights into radiobiological properties have considerably improved patients’ outcomes. This study overviewed the landscape of clinical research at our radiotherapy department.MethodsWe surveyed our institutional database of clinical trials to collect information for completed or ongoing radiation therapy clinical trials, from 2005 to December 2017 at the Lucien Neuwirth cancer institute.ResultsA total of 31 clinical trials were undertaken during the study period, of which 4 studies (12.9%) were industry-sponsored and 3 studies (9.7%) were launched by our radiotherapy unit. The vast majority of clinical trials (83.9%) were dedicated to unique organ localization, especially urological cancer (prostate or bladder) (42%). We also observed a shift towards more phase II trials during the study period as well as a special focus on elderly population. Over the last decade, the number of included patients increased by a 5.3 fold input, with 135 inclusions before 2011 and 720 inclusions after 2011.DiscussionThis study provided an observational and comprehensive analysis of radiotherapy research. From a monocentric point-of-view, these results reflected the on-going progress of worldwide radiotherapy research. Based on a 13-years’ experience, this study aimed at highlighting essential cues to ensure efficient and perennial researc

Mechanisms of PhotoBioModulation (PBM) focused on oral mucositis prevention and treatment: a scoping review

International audienceAbstract Background Oral mucositis (OM) is a severe complication cancer patients undergo when treated with chemoradiotherapy. Photobiomodulation (PBM) therapy also known as low-level laser therapy has been increasingly used for the treatment of such oral toxicity. The aim of this review is to discuss the mechanisms of photobiomodulation (PBM) regarding OM prevention and treatment, and more precisely to focus on the effect of PBM on tumor and healthy cells. Methods MEDLINE/PubMed, and google scholar were searched electronically. Selected studies were focusing on PBM effects on tumor and healthy cells. Results PBM interactions with the tissue and additional mechanism in OM therapy were detailed in this review. Moreover, this review highlighted a controversy about the carcinogenic effect of PBM. Indeed, Many studies reported that PBM could enhance malignant cell proliferation; suggesting that PBM would have no protective effect. In addition to acting on cancer cells, PBM may damage healthy cells. Conclusion More prospective studies are needed to assess the effect of PBM on cancer cells in order to improve its use for OM prevention and treatment

Breast cancer treatment-related cardiovascular disturbances: advocacy for a watchful attitude in this never-ending story

International audienc

The impairement of bone formation and mineralization in BSP−/− mouse calvaria cell cultures is partly rescued by increasing cell density

International audienceBone sialoprotein regulates osteoblast activity and bone formation. In knockout (BSP-/-) mouse bone marrow (BM) stromal cell cultures, the pool of osteoprogenitor (OP) cells (CFU-F number) is not different from wild type (+/+), nor is their early differentiation (same numbers of alkaline phosphatase positive colonies =CFU-ALP, although these are smaller), while the number of osteoblast, mineralized colonies (CFU-OB) is dramatically reduced. Because ossification of newborn BSP-/- mouse calvaria is delayed, we analysed the impact of the mutation on in vitro osteogenesis in cultures of mouse calvaria cells (MCC), isolated from 6 days old mice by collagenase digestion. In contrast to BM, CFU-F, CFU-ALP and CFU-OB numbers were lower in BSP-/- MCC cultures. Consistent with less OP, BSP-/- cultures displayed lower proliferation and delayed growth. In MCC cultures seeded at 5000cell/cm2 osteoblast marker expression did not differ between genotypes until D6. By D14 (=first CFU-OBs) ALP, Coll1, OSX, Runx2 as well as terminal differentiation markers, OCN, PHEX, DMP1 and MEPE increased strongly in BSP+/+ cultures but was low/absent in BSP-/-, with no mineralization. In contrast, osteopontin (OPN) was over-expressed in BSP-/- dishes. At high density (≥25000cell/cm2), marker levels were similar for both genotypes, and BSP-/- cultures mineralized. OPN is a potent inhibitor of mineralization, and was reported to be a substrate for PHEX. Very low PHEX expression in low density BSP-/- cultures suggests that OPN is less degraded and might inhibit mineralization. Increased PHEX expression at higher density would permit OPN degradation and mineralization. Lack of BSP thus reduces MCC culture clonogenicity, differentiation and activity, consistent with lower bone formation in vivo. A BSP-/- bone microenvironment may alter proliferation/cell fate in early OP, explaining the smaller size of CFU-PAL observed in BM cultures

Cardiovascular Diseases Following Breast Cancer

International audienceObjectives: To identify patients at high risk of developing cardiovascular disease through the identification of risk factors among a large population of breast cancer women and to assess the performance of Abdel-Qadir risk prediction model score. Materials and Methods: The medical records and baseline characteristics of all patients/tumors diagnosed with breast cancer from 2010 to 2011 in a French comprehensive cancer center were collected. Cardiovascular events were defined as arterial and cardiac events, atrial fibrillation and venous thromboembolism occurring during the 5-year follow-up. Abdel-Qadir multivariable prediction model for major adverse cardiovascular events were used with the concordance index (c-index) score to assess calibration by comparing predicted risks to observed probabilities. Results: Among the 943 breast cancer patients included, 83 patients (8.8%) presented with at least one cardiovascular event, leading to a cumulative incidence of 0.07 at 5 years (95% confidence interval [CI], 0.055-0.088). The cumulative incidence of atrial fibrillation at 5 years was 0.01 (95% CI, 0.005-0.018). Factors associated with the occurrence of cardiovascular events were pre-existing cardiovascular diseases including high blood pressure (hazard ratio [HR]=1.78, 95% CI=1.07-2.97, P =0.028), acute coronary syndrome (HR=5.28, 95% CI: 2.16-12.88, P <0.05) and grade 3 Scarff-Blool-Richardson (HR=1.95, 95% CI: 1.21-3.15, P =0.006). With a c-index inferior to 0.7, the Abdel-Qadir score was not fully validated in our population. Conclusion: These findings call for the assessment of the performance of risk prediction models such as Abdel-Qadir score coupled with other factors such as Scarff Bloom and Richardson grading in order to identify patients at high risk of experiencing cardiotoxicity

The impairement of bone formation and mineralization in BSP−/− mouse calvaria cell cultures is partly rescued by increasing cell density

International audienceBone sialoprotein regulates osteoblast activity and bone formation. In knockout (BSP-/-) mouse bone marrow (BM) stromal cell cultures, the pool of osteoprogenitor (OP) cells (CFU-F number) is not different from wild type (+/+), nor is their early differentiation (same numbers of alkaline phosphatase positive colonies =CFU-ALP, although these are smaller), while the number of osteoblast, mineralized colonies (CFU-OB) is dramatically reduced. Because ossification of newborn BSP-/- mouse calvaria is delayed, we analysed the impact of the mutation on in vitro osteogenesis in cultures of mouse calvaria cells (MCC), isolated from 6 days old mice by collagenase digestion. In contrast to BM, CFU-F, CFU-ALP and CFU-OB numbers were lower in BSP-/- MCC cultures. Consistent with less OP, BSP-/- cultures displayed lower proliferation and delayed growth. In MCC cultures seeded at 5000cell/cm2 osteoblast marker expression did not differ between genotypes until D6. By D14 (=first CFU-OBs) ALP, Coll1, OSX, Runx2 as well as terminal differentiation markers, OCN, PHEX, DMP1 and MEPE increased strongly in BSP+/+ cultures but was low/absent in BSP-/-, with no mineralization. In contrast, osteopontin (OPN) was over-expressed in BSP-/- dishes. At high density (≥25000cell/cm2), marker levels were similar for both genotypes, and BSP-/- cultures mineralized. OPN is a potent inhibitor of mineralization, and was reported to be a substrate for PHEX. Very low PHEX expression in low density BSP-/- cultures suggests that OPN is less degraded and might inhibit mineralization. Increased PHEX expression at higher density would permit OPN degradation and mineralization. Lack of BSP thus reduces MCC culture clonogenicity, differentiation and activity, consistent with lower bone formation in vivo. A BSP-/- bone microenvironment may alter proliferation/cell fate in early OP, explaining the smaller size of CFU-PAL observed in BM cultures