Attachment to extracellular matrix molecules by cells differing in the expression of osteoblastic traits

Abstract

Two sets of clonal cell populations differing in the expression of osteoblastic traits, the rat osteosarcoma cell lines ROS 17/2.8 and ROS 25/1 and the immortalized fetal rat calvarial cell lines RCT‐1 and RCT‐3, were compared for their ability to attach to a series of extracellular matrix (ECM) constituents in vitro. Both osteoblastic (ROS 17/2.8, RCT‐3) and nonosteoblastic (ROS 25/1, RCT‐1) cell lines attached in a time‐ and concentration‐dependent manner to plates coated with fibronectin (FN), osteopontin (OP), type I collagen (Col I), type IV collagen (Col IV), and laminin (LN) but only weakly to osteocalcin (OC) and thrombospondin (TSP). In both systems, the osteoblastic and nonosteoblastic clones attached identically to FN. Both ROS 17/2.8 and ROS 25/1 attached to similar molar amounts of substrate with the same preference order: FN > LN > Col I ≥ Col IV. Maximal ROS 17/2.8 attachment to OP was ≥ Col I but required approximately 2.5 times more substrate. ROS 25/1 attached less effectively than ROS 17/2.8 to most non‐FN substrates. RCT‐3 cells attached similarly to ROS 17/2.8 except that the preference order for Col I and LN was reversed and attachment to OP was lower than for ROS 17/2.8 RCT‐1 cells attached best to Col I rather than FN, and equaled or surpassed RCT‐3 in attachment to other non‐FN substrates. Thus in these experimental systems, cells expressing an osteoblast‐like phenotype exhibited generally similar ECM attachment properties. Their nonosteoblastic counterparts recognized the same spectrum of ECM constituents but differed from the osteoblastic cells and from each other in the effectiveness of their attachment to substrates other than FN.