Luisa Valvassori

Caveolin-1 Reduces Osteosarcoma Metastases by Inhibiting c-Src Activity and Met Signaling

Caveolin-1 (Cav-1) is highly expressed in normal osteoblasts. This article reports that Cav-1 down-regulation is part of osteoblast transformation and osteosarcoma progression and validates its role as oncosuppressor in human osteosarcoma. A survey of 6-year follow-up indicates a better overall survival for osteosarcoma expressing a level of Cav-1 similar to osteoblasts. However, the majority of primary osteosarcoma shows significantly lower levels of Cav-1 than normal osteoblasts. Accordingly, Met-induced osteoblast transformation is associated with Cav-1 down-regulation. In vitro, osteosarcoma cell lines forced to overexpress Cav-1 show reduced malignancy with inhibited anchorage-independent growth, migration, and invasion. In vivo, Cav-1 overexpression abrogates the metastatic ability of osteosarcoma cells. c-Src and c-Met tyrosine kinases, which are activated in osteosarcoma, colocalize with Cav-1 and are inhibited on Cav-1 overexpression. Thus, Cav-1 behaves as an oncosuppressor in osteosarcoma. Altogether, data suggest that Cav-1 down-modulation might function as a permissive mechanism, which, by unleashing c-Src and Met signaling, enables osteosarcoma cells to invade neighboring tissues. These data strengthen the rationale to target c-Src family kinases and/or Met receptor to improve the extremely poor prognosis of metastatic osteosarcoma.

CD99 suppresses osteosarcoma cell migration through inhibition of ROCK2 activity

CD99, a transmembrane protein encoded by MIC2 gene is involved in multiple cellular events including cell adhesion and migration, apoptosis, cell differentiation and regulation of protein trafficking either in physiological or pathological conditions. In osteosarcoma, CD99 is expressed at low levels and functions as a tumour suppressor. The full-length protein (CD99wt) and the short-form harbouring a deletion in the intracytoplasmic domain (CD99sh) have been associated with distinct functional outcomes with respect to tumour malignancy. In this study, we especially evaluated modulation of cell–cell contacts, reorganisation of the actin cytoskeleton and modulation of signalling pathways by comparing osteosarcoma cells characterised by different metastasis capabilities and CD99 expression, to identify molecular mechanisms responsible for metastasis. Our data indicate that forced expression of CD99wt induces recruitment of N-cadherin and β-catenin to adherens junctions. In addition, transfection of CD99wt inhibits the expression of several molecules crucial to the remodelling of the actin cytoskeleton, such as ACTR2, ARPC1A, Rho-associated, coiled–coil containing protein kinase 2 (ROCK2) as well as ezrin, an ezrin/radixin/moesin family member that has been clearly associated with tumour progression and metastatic spread in osteosarcoma. Functional studies point to ROCK2 as a crucial intracellular mediator regulating osteosarcoma migration. By maintaining c-Src in an inactive conformation, CD99wt inhibits ROCK2 signalling and this leads to ezrin decrease at cell membrane while N-cadherin and β-catenin translocate to the plasma membrane and function as main molecular bridges for actin cytoskeleton. Taken together, we propose that the re-expression of CD99wt, which is generally present in osteoblasts but lost in osteosarcoma, through inhibition of c-Src and ROCK2 activity, manages to increase contact strength and reactivate stop-migration signals that counteract the otherwise dominant promigratory action of ezrin in osteosarcoma cells.

Performance of peripheral (serum and molecular) blood markers for diagnosis of endometriosis.

PurposeTo quantify the mRNA levels of MMP-3, MMP-9, VEGF and Survivin in peripheral blood and the serum levels of CA-125 and Ca19-9 in women with and without endometriosis and to investigate the performance of these markers to differentiate between deep and ovarian endometriosis.MethodsA case control study enrolled a series of 60 patients. Twenty controls have been matched with 20 cases of ovarian and 20 cases of deep endometriosis. Univariable and multivariable performance of serum CA125 and CA19-9, mRNA for Survivin, MMP9, MMP3 and VEGF genes have been evaluated by means of ROC curves and logistic regression, respectively.ResultsNo difference in markers’ concentration was detected between ovarian and deep endometriosis. In comparison with controls, serum CA125 and CA19 yielded the better sensitivity followed by mRNA for Survivin gene (81.5, 51.9 and 7.5% at 10% false positive rate, respectively). Multivariable estimated odds of endometriosis yielded a sensitivity of 87% at the same false positive rate.ConclusionsA combination of serum and molecular markers could allow a better diagnosis of endometriosis.

Matrix Metalloproteinase-3 mRNA: A Promising Peripheral Blood Marker for Diagnosis of Endometriosis

Background/Aims: Endometriosis is an invasive disease. Its diagnosis depends on laparoscopy, which is traumatic and associated with potential complications. The aim of this study was to develop a rapid, reliable, and less invasive diagnostic test for endometriosis. We hypothesized that genes related to cell invasion would be transcriptionally upregulated in endometriosis, and tested whether blood levels of their transcripts might be used as biomarkers of endometriosis.Methods:We used quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) to quantify the mRNA levels of vascular endothelial growth factor A (VEGFA), matrix metalloproteinase-3 (MMP-3), and MMP-9 in peripheral blood from 20 patients with mild/intermediate endometriosis, 20 patients with severe endometriosis and 20 endometriosis-free subjects. Results:Our results indicate that circulating mRNA for MMP-3 is significantly higher in patients with endometriosis than in control patients, regardless of the degree of severity. Conversely, the level of circulating mRNA for VEGFA and MMP-9 did not distinguish patients from controls. Conclusion: MMP-3 mRNA is a promising peripheral blood marker that discriminates between patients with endometriosis and healthy subjects. Our results support the possibility of finding genes suitable for diagnostic qRT-PCR for endometriosis in peripheral blood and should be explored further.