RESUMO
Circular RNAs (circRNAs) are a novel class of endogenous non-coding RNA molecules that are extensively expressed in a variety of species. Recently, increasing evidence suggests that circRNAs have vital functions indifferent types of human cancer, such as gastric cancer, papillary thyroid cancer and lung cancer. However, the roles of circRNAs in the development of colorectal cancer (CRC) remain unclear. The present study aimed to determine the molecular mechanism underlying hsa_circ_0001696 on the proliferation and migration of CRC cells. Reverse transcription-quantitative PCR analysis was performed to detect hsa_circ_0001696 expression in 18 paired CRC tissues and matched adjacent normal tissues. RNA interference was also performed to decrease hsa_circ_0001696 expression, and its biological effects were further assessed via flow cytometry, wound healing, colony formation and western blot assays. The results demonstrated that hsa_circ_0001696 expression was significantly lower in CRC tissues compared with adjacent normal tissues. Furthermore, hsa_circ_0001696 knockdown promoted cell proliferation and migration, and the number of cell colonies significantly increased. In addition, western blot analysis demonstrated that the protein expression levels of cyclin-dependent kinase 4 (CDK4), cyclin D, cyclin E and matrix metalloproteinase 9 (MMP9) increased. Taken together, the results of the present study demonstrated that hsa_circ_0001696 expression was downregulated in CRC tissues, and inhibition of hsa_circ_0001696 promoted cell proliferation and migration by regulating the levels of CDK4, cyclin D, cyclin E and MMP9.
RESUMO
Non-coding RNAs (ncRNAs) play key roles in development, proliferation, differentiation and apoptosis. Altered ncRNA expression is associated with gastric cancer occurrence, invasion, and metastasis. Moreover, aberrant expression of microRNAs (miRNAs) is significantly related to gastric cancer tumor stage, size, differentiation and metastasis. MiRNAs interrupt cellular signaling pathways, inhibit the activity of tumor suppressor genes, and affect the cell cycle in gastric cancer cells. Some miRNAs, including miR-21, miR-106a and miR-421, could be potential markers for the diagnosis of gastric cancer. Long non-coding RNAs (lncRNAs), a new research hotspot among cancer-associated ncRNAs, play important roles in epigenetic, transcriptional and post-transcriptional regulation. Several gastric cancer-associated lncRNAs, such as CCAT1, GACAT1, H19, and SUMO1P3, have been explored. In addition, Piwi-interacting RNAs, another type of small ncRNA that is recognized by gastroenterologists, are involved in gastric carcinogenesis, and piR-651/823 represents an efficient diagnostic biomarker of gastric cancer that can be detected in the blood and gastric juice. Small interfering RNAs also function in post-transcriptional regulation in gastric cancer and might be useful in gastric cancer treatment.