The requirement for matrix proteins along with ERK activation suggests that integrins may be involved in MT1-MMP regulation , a conclusion that is further supported by colocalization of integrins with MT1-MMP in vesicles [46,60] and the existence of common recycling pathways . to collagen I was quantified by an MTS assay. Results Versican Lagociclovir expression was down-regulated in CD26-depleted Karpas 299 cells compared to the parental T-ALCL Karpas 299 cells. Knock down of versican in the parental Karpas 299 cells led to decreased MT1-MMP Lagociclovir surface expression as well as decreased CD44 expression and secretion of the cleaved form of Lagociclovir CD44. Parental Karpas 299 cells also exhibited higher collagenase I activity and greater adhesion to collagenase I than CD26-knockdown or versican-knockdown cells. ERK activation was also highest in parental Karpas 299 cells compared to CD26-knockdown or versican-knockdown clones. Conclusions Our data indicate that CD26 has a key role in cell adhesion and invasion, and potentially in tumorigenesis of T-cell lines, through its association with molecules and signal transduction pathways integral to these processes. Microarray analysis revealed that mRNA level for versican was considerably lower in CD26-depleted Karpas 299 cells than parental Karpas 299 cells (1:88). Although mRNA levels for several other genes, including IGFBP3, tenascin C, and SPOCK1, were also lower in CD26-depleted cells than parental Karpas 299, Western blots confirmed a difference in protein expression for versican only, but not for the other three proteins. Versican is a large chondroitin sulfate proteoglycan involved in the regulation of adhesion, migration, invasion, and angiogenesis . Versican binds to ECM constituents including type I collagen, fibronectin, and hyaluronan (HA)  and a number of cell-surface proteins, including CD44, integrin 1, and toll receptor 2 [25,26]. Versican levels are elevated in most malignancies, and Lagociclovir correlated with poor patient outcome. Versican is secreted by peritumoral stromal cells and also by the individual cancer cells [27,28]. Four major isoforms exist that differ with respect to the number and position of GAG molecules attached, which are important for association with other proteins. Of note is that the V0 and V1 isoforms are reported to be the isoforms most closely associated with cancers. In the present paper, we examined in detail CD26 involvement with cell migration and adhesion in T-cell lines. Expression array analyses of genes involved in extracellular matrix and adhesion pathways indicated that versican expression was significantly higher in parental T-ALCL Karpas 299 cells compared to CD26-depleted FGF3 Karpas 299 cells. To further investigate the relationship between CD26 and versican, we conducted knock down studies of versican in Karpas 299 cells and evaluated for a potential effect on expression of signaling proteins and adhesion. We found that the use of shRNA to knock down versican expression in the parental Karpas 299 cells resulted in both lower MT1-MMP transcription and surface expression. To confirm that cell behavior was consistent with the observed change in MT1-MMP activity, several assays were performed; secretion and cleavage of CD44, collagenase I activity, and adhesion. In all three assays, parental Karpas 299 cells exhibited higher activity compared to cells in which CD26 or versican was knocked down. Finally, ERK activation, which is required for migration and invasion, was also highest in the parental Karpas 299 cell line. Methods Reagents Bovine serum albumin (BSA), polybrene (hexadimethrine bromide), sodium dodecyl sulfate, glycine, sodium deoxycholate, trypsin, phosphate buffered saline, and dimethyl sulfoxide were from Sigma Life Science, St. Louis, MO. TX-100, NP-40, and Tween-20 were from Fisher Scientific, USA. Puromycin was from Life Technologies, USA. Rat tail collagen and bovine skin collagen were purchased from BD and Advanced Matrix, respectively. GM6001, a general MMP inhibitor was purchased from Calbiochem. Cell culture Karpas 299 cells were originally obtained from the American Type Culture Collection Lagociclovir (ATCC, Manassas, VA) and maintained in RPMI-1640 (Hyclone, Logan, UT). Karpas 299 cells depleted of CD26 have been described previously . All cell media contained 10% fetal bovine serum (Hyclone), penicillin (100 u/ml) and streptomycin (100?g/ml). Expression arrays GEArray express human extracellular matrix and adhesion molecule microarrays were carried out by SuperArray Bioscience Corporation on 10?g total RNA isolated from parental Karpas 299 cells and Dep1, a cell line deficient in CD26.