No abstract

No abstract

IntroductionRecent evidence suggests that tumour lymphangiogenesis promotes lymph node metastasis, a major prognostic factor for survival of breast cancer patients. However, signaling mechanisms involved in tumour-induced lymphangiogenesis remain poorly understood. The expression of ezrin, a membrane cytoskeletal crosslinker and Src substrate, correlates with poor outcome in a diversity of cancers including breast. Furthermore, ezrin is essential in experimental invasion and metastasis models of breast cancer. Ezrin acts cooperatively with Src in the regulation of the Src-induced malignant phenotype and metastasis. However, it remains unclear if ezrin plays a role in Src-induced tumour angio/lymphangiogenesis.MethodsThe effects of ezrin knockdown and mutation on angio/lymphangiogenic potential of human MDA-MB-231 and mouse AC2M2 mammary carcinoma cell lines were examined in the presence of constitutively active or wild-type (WT) Src. In vitro assays using primary human lymphatic endothelial cells (hLEC), an ex vivo aortic ring assay, and in vivo tumour engraftment were utilized to assess angio/lymphangiogenic activity of cancer cells.ResultsEzrin-deficient cells expressing activated Src displayed significant reduction in endothelial cell branching in the aortic ring assay in addition to reduced hLEC migration, tube formation, and permeability compared to the controls. Intravital imaging and microvessel density (MVD) analysis of tumour xenografts revealed significant reductions in tumour-induced angio/lymphangiogenesis in ezrin-deficient cells when compared to the WT or activated Src-expressing cells. Moreover, syngeneic tumours derived from ezrin-deficient or Y477F ezrin-expressing (non-phosphorylatable by Src) AC2M2 cells further confirmed the xenograft results. Immunoblotting analysis provided a link between ezrin expression and a key angio/lymphangiogenesis signaling pathway by revealing that ezrin regulates Stat3 activation, VEGF-A/-C and IL-6 expression in breast cancer cell lines. Furthermore, high expression of ezrin in human breast tumours significantly correlated with elevated Src expression and the presence of lymphovascular invasion.ConclusionsThe results describe a novel function for ezrin in the regulation of tumour-induced angio/lymphangiogenesis promoted by Src in breast cancer. The combination of Src/ezrin might prove to be a beneficial prognostic/predictive biomarker for early-stage metastatic breast cancer.Electronic supplementary materialThe online version of this article (doi:10.1186/s13058-014-0438-2) contains supplementary material, which is available to authorized users.

No abstract

TPS10129 Background: Innovative radiotherapy technology and modern imaging capabilities enable the use of Stereotactic Body Radiotherapy (SBRT) to treat patients with spinal metastases to optimize tumour control and palliation compared to standard conventional radiotherapy. No randomized clinical trial evidence exists directly comparing the two treatment strategies. Methods: SC.24 is a Canadian Cancer Trials Group randomized phase II/III study comparing standard conventional radiotherapy (20 Gy/5fr) to SBRT (24 Gy/2fr) in patients with solid tumours and MRI documented, painful spinal metastases suitable for RT. The primary accrual objective for the phase II portion of the study was met in January 2017 and the study continues as a randomized phase III study with a primary outcome measure of complete pain response at 3 months post radiotherapy. Secondary objectives include: measurement of complete pain response at 6 months; radiation site progression free survival at 3 and 6 months; adverse event profile, health related QOL and compliance with RT QA measures. Biobanking for future correlative studies is included in study design. Statistical design: The statistical assumptions for the phase III study include estimated complete pain response rates of 10% and 30% for the CRT and SBRT treatment arms respectively. Using a two sided alpha = 0.05 and power = 80% the sample size for the phase III study is 152, taking into account a 5% drop out rate. Conduct to Date: Study activation: July 2015. Accrual to date: 58. Supported by CCSRI grant 021039 Clinical trial information: NCT02512965.