Aim: To screen lymph nodes metastasis associated long noncoding RNAs (lncRNAs) in colorectal cancer through microarray analysis.
Methods: Metastatic lymph node (MLN), normal lymph node (NLN) and tumor tissues of 3 colorectal cancer (CRC) patients were collected during the operation and validated by pathological examinations. RNAs were extracted from MLN, NLN, and cancer tissues separately. RNA quantity and quality were measured with a NanoDrop ND-1000 spectrophotometer and RNA integrity was assessed by standard denaturing agarose electrophoresis. Agilent Feature Extraction Software (Version 11.0.1.1) was used to analyze acquired array images. Four differently expressed lncRNAs were confirmed by quantitative real-time polymerase chain reaction (qRT-PCR) in 26 subsets of MLN, NLN, and tumor tissues.
Results: Of 33045 lncRNAs, 1133 were differentially expressed in MLN compared with NLN, of which 260 were up-regulated and 873 down-regulated (≥ 2 fold-change). Five hundred and forty-five lncRNAs were differentially expressed in MLN compared with tumor tissues, of which 460 were up-regulated and 85 down-regulated (≥ 2 fold-change). Compared with NLN and cancer tissues, 14 lncRNAs were specifically up-regulated and 5 specifically down-regulated in MLN. AK307796, ENST00000425785, and AK021444 were confirmed to be specifically up-regulated in MLN and ENST00000465846 specifically down-regulated in MLN by qRT-PCR in 26 CRC patients.
Conclusion: The specifically expressed lncRNAs in MLN may exert a partial or key role in the progress of lymph nodes metastasis of CRC.
Keywords: Colorectal cancer; Long noncoding RNAs; Lymph nodes metastasis; MicroRNA; Quantitative real-time polymerase chain reaction.