22 research outputs found

    Molecular mechanisms underpinning sarcomas and implications for current and future therapy

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    Sarcomas are complex mesenchymal neoplasms with a poor prognosis. Their clinical management is highly challenging due to their heterogeneity and insensitivity to current treatments. Although there have been advances in understanding specific genomic alterations and genetic mutations driving sarcomagenesis, the underlying molecular mechanisms, which are likely to be unique for each sarcoma subtype, are not fully understood. This is in part due to a lack of consensus on the cells of origin, but there is now mounting evidence that they originate from mesenchymal stromal/stem cells (MSCs). To identify novel treatment strategies for sarcomas, research in recent years has adopted a mechanism-based search for molecular markers for targeted therapy which has included recapitulating sarcomagenesis using in vitro and in vivo MSC models. This review provides a comprehensive up to date overview of the molecular mechanisms that underpin sarcomagenesis, the contribution of MSCs to modelling sarcomagenesis in vivo, as well as novel topics such as the role of epithelial-to-mesenchymal-transition (EMT)/mesenchymal-to-epithelial-transition (MET) plasticity, exosomes, and microRNAs in sarcomagenesis. It also reviews current therapeutic options including ongoing preclinical and clinical studies for targeted sarcoma therapy and discusses new therapeutic avenues such as targeting recently identified molecular pathways and key transcription factors.The authors were supported by grants from the South Africa Medical Research Council (SAMRC), the National Research Foundation (NRF), Cancer Association of South Africa (CANSA) and the Universities of Cape Town and Pretoria.The South Africa Medical Research Council (SAMRC), the National Research Foundation (NRF), Cancer Association of South Africa (CANSA) and the Universities of Cape Town and Pretoria.http://www.nature.com/sigtrans/Immunolog

    Estimating oceanic primary production using vertical irradiance and chlorophyll profiles from ocean gliders in the North Atlantic

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    An autonomous underwater vehicle (Seaglider) has been used to estimate marine primary production (PP) using a combination of irradiance and fluorescence vertical profiles. This method provides estimates for depth-resolved and temporally evolving PP on fine spatial scales in the absence of ship-based calibrations. We describe techniques to correct for known issues associated with long autonomous deployments such as sensor calibration drift and fluorescence quenching. Comparisons were made between the Seaglider, stable isotope (13C), and satellite estimates of PP. The Seaglider-based PP estimates were comparable to both satellite estimates and stable isotope measurements

    The c-Myc/TBX3 axis promotes cellular transformation of sarcoma-initiating cells

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    Sarcomas are highly aggressive cancers of mesenchymal origin whose clinical management is highly complex. This is partly due to a lack of understanding of the molecular mechanisms underpinning the transformation of mesenchymal stromal/stem cells (MSCs) which are presumed to be the sarcoma-initiating cells. c-Myc is amplified/ overexpressed in a range of sarcomas where it has an established oncogenic role and there is evidence that it contributes to the malignant transformation of MSCs. T-box transcription factor 3 (TBX3) is upregulated by c-Myc in a host of sarcoma subtypes where it promotes proliferation, tumor formation, migration, and invasion. This study investigated whether TBX3 is a c-Myc target in human MSCs (hMSCs) and whether overexpressing TBX3 in hMSCs can phenocopy c-Myc overexpression to promote malignant transformation. Using siRNA, qRT-PCR, luciferase reporter and chromatinimmunoprecipitation assays, we show that c-Myc binds and directly activates TBX3 transcription in hMSCs at a conserved E-box motif. When hMSCs were engineered to stably overexpress TBX3 using lentiviral gene transfer and the resulting cells characterised in 2D and 3D, the overexpression of TBX3 was shown to promote self-renewal, bypass senescence, and enhance proliferation which corresponded with increased levels of cell cycle progression markers (cyclin A, cyclin B1, CDK2) and downregulation of the p14ARF/ MDM2/p53 tumor suppressor pathway. Furthermore, TBX3 promoted the migratory and invasive ability of hMSCs which associated with increased levels of markers of migration (Vimentin, SLUG, SNAIL, TWIST1) and invasion (MMP2, MMP9). Transcriptomic analysis revealed that genes upregulated upon TBX3 overexpression overlapped with c-myc targets, were involved in cell cycle progression, and were associated with sarcomagenesis. Together, the data described indicate that the c-Myc/TBX3 oncogenic molecular pathway may be a key mechanism that transforms hMSCs into sarcomas.South Africa Medical Research Council (SAMRC); National Research Foundation (NRF); Cancer Association of South Africa (CANSA); Universities of Cape Town and Pretoria.https://www.frontiersin.org/journals/oncologydm2022ImmunologyOral Pathology and Oral Biolog

    The c-Myc/AKT1/TBX3 Axis Is Important to Target in the Treatment of Embryonal Rhabdomyosarcoma

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    Rhabdomyosarcoma is a highly aggressive malignant cancer that arises from skeletal muscle progenitor cells and is the third most common solid tumour in children. Despite significant advances, rhabdomyosarcoma still presents a therapeutic challenge, and while targeted therapy has shown promise, there are limited options because the molecular drivers of rhabdomyosarcoma are poorly understood. We previously reported that the T-box transcription factor 3 (TBX3), which has been identified as a druggable target in many cancers, is overexpressed in rhabdomyosarcoma patient samples and cell lines. To identify new molecular therapeutic targets to treat rhabdomyosarcoma, this study investigates the potential oncogenic role(s) for TBX3 and the factors responsible for upregulating it in this cancer. To this end, rhabdomyosarcoma cell culture models in which TBX3 was either stably knocked down or overexpressed were established and the impact on key hallmarks of cancer were examined using growth curves, soft agar and scratch motility assays, as well as tumour-forming ability in nude mice. Our data show that TBX3 promotes substrate-dependent and -independent proliferation, migration and tumour formation. We further reveal that TBX3 is upregulated by c-Myc transcriptionally and AKT1 post-translationally. This study identifies c-Myc/AKT1/TBX3 as an important axis that could be targeted for the treatment of rhabdomyosarcoma

    TBX3 Promotes Melanoma Migration by Transcriptional Activation of ID1, which Prevents Activation of E-Cadherin by MITF

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    International audienceIn melanoma, a phenotype switch from proliferation to invasion underpins metastasis, the major cause of melanoma-associated death. The transition from radial to vertical growth phase (invasive) melanoma is characterized by downregulation of both E-cadherin (CDH1) and MITF and upregulation of the key cancer-associated gene TBX3 and the phosphatidylinositol 3 kinase signaling pathway. Yet, whether and how these diverse events are linked remains poorly understood. Here, we show that TBX3 directly promotes expression of ID1, a dominant-negative regulator of basic helix-loop-helix transcription factors, and that ID1 decreases MITF binding and upregulation of CDH1. Significantly, we show that TBX3 activation of ID1 is necessary for TBX3 to enhance melanoma cell migration, and the mechanistic links between TBX3, ID1, MITF, and invasion revealed here are reflected in their expression in human melanomas. Our results reveal that melanoma migration is promoted through a TBX3-ID1-MITF-E-cadherin axis and that ID1-mediated repression of MITF activity may reinforce maintenance of an MITF(Low) phenotype associated with disease progression and therapy resistance

    Cohort profile : Biomarkers related to folate-dependent one-carbon metabolism in colorectal cancer recurrence and survival - The FOCUS Consortium

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    Purpose The overarching goal of the FOCUS (biomarkers related to folate-dependent one-carbon metabolism in colorectal cancer (CRC) recurrence and survival) Consortium is to unravel the effect of folate and folate-mediated one-carbon metabolism (FOCM) biomarkers on CRC prognosis to provide clinically relevant advice on folate intake to cancer patients and define future tertiary prevention strategies. Participants The FOCUS Consortium is an international, prospective cohort of 2401 women and men above 18 years of age who were diagnosed with a primary invasive non-metastatic (stages I-III) CRC. The consortium comprises patients from Austria, two sites from the Netherlands, Germany and two sites from the USA. Patients are recruited after CRC diagnosis and followed at 6 and 12 months after enrolment. At each time point, sociodemographic data, data on health behaviour and clinical data are collected, blood samples are drawn. Findings to date An increased risk of cancer recurrences was observed among patients with higher compared with lower circulating folic acid concentrations. Furthermore, specific folate species within the FOCM pathway were associated with both inflammation and angiogenesis pathways among patients with CRC. In addition, higher vitamin B 6 status was associated with better quality of life at 6 months post-treatment. Future plans Better insights into the research on associations between folate and FOCM biomarkers and clinical outcomes in patients with CRC will facilitate the development of guidelines regarding folate intake in order to provide clinically relevant advice to patients with cancer, health professionals involved in patient care, and ultimately further tertiary prevention strategies in the future. The FOCUS Consortium offers an excellent infrastructure for short-term and long-term research projects and for combining additional biomarkers and data resulting from the individual cohorts within the next years, for example, microbiome data, omics and multiomics data or CT-quantified body composition data

    Associations of combined physical activity and body mass index groups with colorectal cancer survival outcomes

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    Abstract Background Physical activity and BMI have been individually associated with cancer survivorship but have not yet been studied in combinations in colorectal cancer patients. Here, we investigate individual and combined associations of physical activity and BMI groups with colorectal cancer survival outcomes. Methods Self-reported physical activity levels (MET hrs/wk) were assessed using an adapted version of the International Physical Activity Questionnaire (IPAQ) at baseline in 931 patients with stage I-III colorectal cancer and classified into ‘highly active’ and’not-highly active’(≥ / < 18 MET hrs/wk). BMI (kg/m2) was categorized into ‘normal weight’, ‘overweight’, and ‘obese’. Patients were further classified into combined physical activity and BMI groups. Cox-proportional hazard models with Firth correction were computed to assess associations [hazard ratio (HR), 95% profile HR likelihood confidence interval (95% CI) between individual and combined physical activity and BMI groups with overall and disease-free survival in colorectal cancer patients. Results ‘Not-highly active’ compared to ‘highly active’ and ‘overweight’/ ‘obese’ compared to ‘normal weight’ patients had a 40–50% increased risk of death or recurrence (HR: 1.41 (95% CI: 0.99–2.06), p = 0.03; HR: 1.49 (95% CI: 1.02–2.21) and HR: 1.51 (95% CI: 1.02–2.26), p = 0.04, respectively). ‘Not-highly active’ patients had worse disease-free survival outcomes, regardless of their BMI, compared to ‘highly active/normal weight’ patients. ‘Not-highly active/obese’ patients had a 3.66 times increased risk of death or recurrence compared to ‘highly active/normal weight’ patients (HR: 4.66 (95% CI: 1.75–9.10), p = 0.002). Lower activity thresholds yielded smaller effect sizes. Conclusion Physical activity and BMI were individually associated with disease-free survival among colorectal cancer patients. Physical activity seems to improve survival outcomes in patients regardless of their BMI

    The roles and regulation of TBX3 in development and disease

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