Abstract
BackgroundPodoplanin (PDPN) is a mucin-type transmembrane glycoprotein specific to the lymphatic system. PDPN expression has been found in various human tumors and is considered to be a marker of cancer. We had previously shown that PDPN expression contributes to carcinogenesis in the TPC1 papillary thyroid cancer-derived cell line by enhancing cell migration and invasiveness. The aim of this study was to determine the effect of PDPN down-regulation in another thyroid cancer-derived cell line: BcPAP.MethodsIn order to determine the effects of PDPN on malignant features of BcPAP cells (harboring the BRAFV600E mutated allele) and TPC1 cells (carrying the RET/PTC1 rearrangement), we silenced PDPN in these cells using small interfering RNA (siRNA). The efficacy of PDPN silencing was confirmed by qRT-PCR and Western blotting. Then, we tested the motility and invasiveness of these cells (using scratch test and Transwell assay), their growth capacities F(cell cycle analysis, viability, clonogenic activity) and apoptosis assays), adhesion-independent colony-formation capacities, as well as the effect of PDPN silencing on MMPs expression and activity (zymography).ResultsWe found that PDPN-induced cell phenotype depended on the genetic background of thyroid tumor cells. PDPN down-regulation in BcPAP cells was negatively correlated with the migration and invasion, in contrast to TPC1 cells in which PDPN depletion resulted in enhanced migration and invasiveness. Moreover, our results suggest that in BcPAP cells, PDPN may be involved in the epithelial-mesenchymal transition (EMT) through regulating the expression of the ezrin, radixin and moesin (E/R/M) proteins, MMPs 9 and MMP2, remodeling of actin cytoskeleton and cellular protrusions. We also demonstrated that PDPN expression is associated with the MAPK signaling pathway. The inhibition of the MAPK pathway resulted in a decreased PDPN expression, increased E/R/M phosphorylation and reduced cell migration. Additionally, PDPN depleted BcPAP cells treated with inhibitors of MEK1/2 kinases (U0126) or of the BRAF V600E protein (PLX4720) had reduced motility, similar to that previously observed in TPC1 cells after PDPN knock-down.ConclusionsAltogether, our data suggest that PDPN may play an important role in the control of invasion and migration of papillary thyroid carcinoma cells in association with the E/R/M, MMPs and MAPK kinases.
Highlights
Podoplanin (PDPN) is a mucin-type transmembrane glycoprotein specific to the lymphatic system
Podoplanin silencing in papillary thyroid cancer cell lines In order to assess the role of PDPN in the biology of papillary thyroid cancer, we silenced the expression of PDPN in two papillary thyroid cancer cell lines: TPC1 and Papillary thyroid carcinoma (BcPAP) by transfection with targeted small interfering RNA (siRNA)
The effect of podoplanin silencing on the motility, invasiveness, adhesion and proliferation of papillary thyroid cancer cells Since the migration and invasion of cancer cells are crucial factors responsible for cancer progression, we first examined whether PDPN may impact the ability of cells to migrate
Summary
Podoplanin (PDPN) is a mucin-type transmembrane glycoprotein specific to the lymphatic system. We had previously shown that PDPN expression contributes to carcinogenesis in the TPC1 papillary thyroid cancer-derived cell line by enhancing cell migration and invasiveness. Podoplanin (PDPN) is a 38–40 kDa type I mucin-like transmembrane sialoglycoprotein which belongs to the podoplanin family [1,2,3] It was initially identified in the kidney as a marker of podocytes [4] but it is expressed in numerous other human tissues, such as skeletal muscles, heart, placenta, and lung [4,5,6,7]. High ectopic expression of PDPN has been shown to result in enhanced cancer cell migration, lymphangiogenesis and metastasis in the human MCF7 breast carcinoma xenograft model [26]. Martín-Villar and collaborators showed that PDPN contributes to both directional migration of normal epithelial cells and cells derived from squamous cell carcinomas (SCC) [27]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
