BACKGROUNDTo observe and explore the effects and mechanisms of fibronectin (FN) on invasion of different types of lung cancers.

METHODSUsing tumor invasion models in vitro of plates coated with FN and Boyden chambers with FN filter, differences of adhesion and migration between small cell lung cancer cell line (054A) and adenocarcinoma cell line (A549) were investigated, and proliferative effects of FN on cells were examined. In the meantime the invasive capability changes were observed after cell suspensions were preincubated with anti-α5, anti-α3 and anti-β1 integrin antibodies, respectively.

RESULTSFN could improve the adhesion, migration and proliferation of A549 more markedly than that of 054A. The number of adhesive cells in A549 cell line changed from 34.7± 5.1 to 189.4±12.3 with time from 2h to 12h compared with that from 19.8±7.9 to 159.2±11.9 in 054A cell line (P < 0.05 or P < 0.01). A549 cell line had 142.7±5.9 migration cells while 054A cell line had 89.4±4.7 (P < 0.01). FN could improved the proliferation in A549 cell line from 0.250±0.019 to 0.754±0.025 (P < 0.01) in concentration-dependent way, but in 054A from 0.205±0.026 to 0.286±0.029. And these effects were mediated mainly by α3β1 and α5β1 receptors in A549, but α3β1 in 054A.

CONCLUSIONSLung cancers with different origins express so different types and extents of integrin receptors that effects of FN on tumors are various, which is one of important reasons of different invasive capability of lung cancers.