Unveiling the role of osteosarcoma-derived secretome in premetastatic lung remodelling.

BACKGROUND: Lung metastasis is the most adverse clinical factor and remains the leading cause of osteosarcoma-related death. Deciphering the mechanisms driving metastatic spread is crucial for finding open therapeutic windows for successful organ-specific interventions that may halt or prevent lung metastasis. METHODS: We employed a mouse premetastatic lung-based multi-omics integrative approach combined with clinical features to uncover the specific changes that precede lung metastasis formation and identify novel molecular targets and biomarker of clinical utility that enable the design of novel therapeutic strategies. RESULTS: We found that osteosarcoma-bearing mice or those preconditioned with the osteosarcoma cell secretome harbour profound lung structural alterations with airway damage, inflammation, neutrophil infiltration, and extracellular matrix remodelling with increased deposition of fibronectin and collagens by resident stromal activated fibroblasts, favouring the adhesion of disseminated tumour cells. Systemic-induced microenvironmental changes, supported by transcriptomic and histological data, promoted and accelerated lung metastasis formation. Comparative proteome profiling of the cell secretome and mouse plasma identified a large number of proteins involved in extracellular-matrix organization, cell-matrix adhesion, neutrophil degranulation, and cytokine-mediated signalling, consistent with the observed lung microenvironmental changes. Moreover, we identified EFEMP1, an extracellular matrix glycoprotein exclusively secreted by metastatic cells, in the plasma of mice bearing a primary tumour and in biopsy specimens from osteosarcoma patients with poorer overall survival. Depletion of EFEMP1 from the secretome prevents the formation of lung metastasis. CONCLUSIONS: Integration of our data uncovers neutrophil infiltration and the functional contribution of stromal-activated fibroblasts in ECM remodelling for tumour cell attachment as early pro-metastatic events, which may hold therapeutic potential in preventing or slowing the metastatic spread. Moreover, we identified EFEMP1, a secreted glycoprotein, as a metastatic driver and a potential candidate prognostic biomarker for lung metastasis in osteosarcoma patients. Osteosarcoma-derived secreted factors systemically reprogrammed the lung microenvironment and fostered a growth-permissive niche for incoming disseminated cells to survive and outgrow into overt metastasis. Daily administration of osteosarcoma cell secretome mimics the systemic release of tumour-secreted factors of a growing tumour in mice during PMN formation; Transcriptomic and histological analysis of premetastatic lungs revealed inflammatory-induced stromal fibroblast activation, neutrophil infiltration, and ECM remodelling as early onset pro-metastatic events; Proteome profiling identified EFEMP1, an extracellular secreted glycoprotein, as a potential predictive biomarker for lung metastasis and poor prognosis in osteosarcoma patients. Osteosarcoma patients with EFEMP1 expressing biopsies have a poorer overall survival.

Impact of Positive Surgical Margins After Partial Nephrectomy.

BACKGROUND: The impact of positive surgical margins (PSMs) after partial nephrectomy (PN) is controversial. OBJECTIVE: To evaluate the risk factors for a PSM and its impact on overall survival. DESIGN SETTING AND PARTICIPANTS: This is a retrospective study of 388 patients were submitted to PN between November 2005 and December 2016 in a single centre. Two groups were created: PSM and negative surgical margin (NSM) after PN. A p value of <0.05 was considered significant. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Relationships with outcome were assessed using univariable and multivariable tests and log-rank analysis. RESULTS AND LIMITATIONS: The PSM rate was 3.8% (N = 16). The mean age at the time of surgery (PSM group: 64.1 ± 11.3 vs NSM group: 61.8 ± 12.8 yr, p = 0.5) and the mean radiological tumour size (4.0 ± 1.5 vs 3.4 ± 1.8 cm, p = 0.2) were similar. Lesion location (p = 0.3), surgical approach (p = 0.4), warm ischaemia time (p = 0.9), and surgery time (p = 0.06) had no association with PSM. However, higher surgeon experience was associated with a lower PSM incidence (2.6% if ≥30 PNs vs 9.6% if <30 PNs; p = 0.02). Higher operative blood loss (p = 0.02), higher-risk tumours (p = 0.03), and larger pathological size (p = 0.05) were associated with an increase in PSM. In the PSM group, recurrence rate (18.7% vs 4.2%, p = 0.007) and secondary total nephrectomy rate (25% vs 4.4%, p < 0.001) were higher. However, overall survival was similar. Multivariate analysis revealed that high-risk tumour (p = 0.05) and low experience (p = 0.03) could predict a PSM. Limitations include retrospective design and reduced follow-up time. CONCLUSIONS: PSMs were mainly associated with high-risk pathological tumour (p = 0.05) and low-volume surgeon experience. Recurrence rate and need for total nephrectomy were higher in that group, but no impact on survival was noticed. PATIENT SUMMARY: The impact of positive surgical margins (PSMs) after partial nephrectomy is a matter of debate. In this study, we found that PSMs were mainly associated with aggressive disease and low surgeon experience.