Jun Wang

Department of Oncology, Jinan MilitaryGeneral Hospital.

Objective:HuR is a RNA-binding protein andcontributes to cancer development and progression, but mechanisms underlyingaltered HuR expression in cancer remain unclear. In this study, we showed thatmiR-133b regulated HuR expression at post transcriptional levels in non-smallcell lung carcinoma. Method: We analyzed cytoplasmic HuR expression byimmunohistochemistry and miR-133b expression by real-time RT-PCR in 33 lungcancer specimens and parried normal lung epithelium specimens, as well as 110paraffin-embedded lung cancer specimens. Human lung adenocarcinoma cancer 95Dand H1299 cells were cultured and used for series of experiments. The miR-133bmimics, miR-133b inhibitors and control miRNA were transiently transfected intolung cancer cells. MTT assay and Western blotting was used to analyze cellproliferation and protein expression. The mRNA and miR-133b levels in cellswere measured by real-time RT-PCR. Luciferase assays were conducted to analyzewhether miR-133b can directly bind to and regulate HuR expression. We allevaluated the relationship of miR-133b level with clinincopathological featuresor survival. Result: In lung cancer cells and clinical tissues, miR-133bexpression was expressed at low levels and cytoplasmic HuR was expressed athigh levels through qRT-PCR or Immunohistochemistry. Wound healing, transwellmigration and invasion experiments in vitro and experimental lung metastasesindicated that miR-133b over expression inhibited lung cancer cell migration, invasionand the formation of lung metastases in vivo. Furthermore, luciferase reportassays showed that HuR was confirmed a miR-133b target gene.Clinicopathological studies showed that miR-133b down regulation wassignificantly with cytoplasmic HuR expression, and act as an independentprognostic factor for patients with NSCLC. Conclusion: These resultssuggest the molecular mechanisms regulating HuR expression, invasion andmetastasis, and elucidate a new therapeutic and prognostic strategy in lungcancer.

KeyWords: miR-133b Lung cancer  Prognosis