Ovarian carcinoma spheroids disaggregate on type I collagen and invade live human mesothelial cell monolayers

Abstract

Ovarian carcinoma patients frequently develop malignant ascites containing single and aggregated tumor cells, or spheroids. Spheroids have been shown to be resistant to many therapies, but their contribution to ovarian cancer dissemination remains undetermined. We have previously shown that ascites spheroids adhere to extracellular matrix (ECM) proteins and live human mesothelial cells via beta1 integrin subunits. Here, we assessed the ability of spheroids that were generated from the human ovarian carcinoma cell line NIH:OVCAR5 to disseminate and invade in vitro. Spheroids were seeded on ECM proteins for 24 h. While laminin and type IV collagen stimulated some cell migration, spheroids completely disaggregated on type I collagen substrates. A monoclonal antibody against the beta1 integrin subunit significantly inhibited disaggregation on all proteins tested. To test their invasive ability, spheroids were added to monolayers of live human LP9 mesothelial cells. Within 24 h, the spheroids adhered and disaggregated on top of the monolayers, and within a week had established foci of invasion encompassing a 200-fold larger surface area. Addition of a monoclonal antibody against the beta1 integrin subunit drastically reduced spheroid invasion into the mesothelial cell monolayers. GM 6001, a broad-scale matrix metalloproteinase inhibitor, also significantly blocked spheroid invasion into the mesothelial cell monolayers. Epsilon-amino-N-caproic acid, a serine protease inhibitor, partially inhibited spheroid invasion. Based on their ability to attach to, disaggregate on, and invade into live human mesothelial cell monolayers, spheroids should thus be regarded as potential contributors to the dissemination of ovarian cancer.

MT1-MMP is the critical determinant of matrix degradation and invasion by ovarian cancer cells

“…Further, matrices composed of collagen I stimulated the most rapid/extensive dissemination of ovarian cancer cells from spheroids (Burleson et al, 2004). Although Matrigelt has been commonly used for invasion assays, its suitability for this purpose has recently been challenged (Hotary et al, 2006).…”

“…In contrast to most other solid tumours, which metastasise through a multi-step haematological route, ovarian cancer cells metastasise via exfoliation from the primary tumour into the peritoneal cavity. Ovarian cancer cells preferentially bind collagen I and this ligand is highly effective in stimulating motility in these cells (Moser et al, 1996;Burleson et al, 2004). Indeed, during peritoneal metastasis, tumour cells attach preferentially at locations where the mesothelium is disrupted and the underlying collagen I-rich stromal matrix is exposed (Ghosh et al, 2002;Mochizuki et al, 2004).…”

Mesenchymal gene program–expressing ovarian cancer spheroids exhibit enhanced mesothelial clearance

“…Ovarian cancer cells can attach and spread on multiple ECM proteins associated with the mesothelium and underlying basement membrane, including collagen I, collagen IV, laminin, vitronectin, and fibronectin; α and β integrins, as well as CD44, have been shown to serve as tumor cell receptors for these ligands (9,(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). While ovarian cancer cell adhesion and spreading on mesothelial monolayers has been well characterized, there has been much less focus on understanding the mechanisms associated with ovarian cancer cell invasion into and displacement of cells in the mesothelial monolayer.…”

A multiscale road map of cancer spheroids – incorporating experimental and mathematical modelling to understand cancer progression

“…These cells then adhere to the mesothelial cell layer that covers the peritoneal organs and invade into the underlying extracellular matrix (ECM), where they grow secondary tumours. These events are clearly the crucial steps that lead to poor patient outcomes (Burleson et al, 2005;Dong et al, 2010;Moss et al, 2009;Sawada et al, 2008;Symowicz et al, 2007). However, little is known with regards to the underlying mechanisms that facilitate metastasis and subsequently result in chemoresistance.…”