Atherosclerosis and related cardiovascular diseases pose severe threats to human 
health worldwide. There is evidence to suggest that at least 50% of foam cells 
in atheromas are derived from vascular smooth muscle cells (VSMCs); the first 
step in this process involves migration to human atherosclerotic lesions. Long 
non‑coding RNAs (lncRNAs) have been found to play significant roles in diverse 
biological processes. The present study aimed to investigate the role of lncRNAs 
in VSMCs. The expression of lncRNAs or mRNAs was detected using reverse 
transcription‑quantitative polymerase chain reaction. The Gene Expression 
Omnibus datasets in the NCBI portal were searched using the key words 
'Atherosclerosis AND tissue AND Homo sapiens' and the GSE12288 dataset. Gene 
expression in circulating leukocytes was measured to identify patients with 
coronary artery disease (CAD) or controls, and used to analyze the correlation 
coefficient and expression profiles. The protein level of ATP‑binding cassette 
sub‑family G member 1 (ABCG1) and matrix metalloproteinase (MMP)3 was determined 
using immunohistochemistry and western blot analysis. The analysis of mouse 
aortic roots was performed using Masson's and Oil Red O staining. The expression 
of lncRNA AL355711, ABCG1 and MMP3 was found to be higher in human 
atherosclerotic plaques or in patients with atherosclerotic CAD. The correlation 
analysis revealed that ABCG1 may be involved in the regulation between lncRNA 
AL355711 and MMP3 in atherosclerotic CAD. The knockdown of lncRNA AL355711 
inhibited ABCG1 transcription and smooth muscle cell migration. In addition, 
lncRNA AL355711 was found to regulate MMP3 expression through the ABCG1 pathway. 
The expression of ABCG1 and MMP3 was found to be high in an animal model of 
atherosclerosis. The results indicated that lncRNA AL355711 promoted VSMC 
migration and atherosclerosis partly via the ABCG1/MMP3 pathway. On the whole, 
the present study demonstrates that the inhibition of lncRNA AL355711 may serve 
as a novel therapeutic target for atherosclerosis. lncRNA AL355711 in 
circulating leukocytes may be a novel biomarker for atherosclerotic CAD.