Citation

  • Authors: Bissey, P. A., Law, J. H., Bruce, J. P., Shi, W., Renoult, A., Chua, M. L. K., Yip, K. W., Liu, F. F.
  • Year: 2018
  • Journal: Oncogenesis 7 40
  • Applications: in vitro / DNA, pre-miRNA / jetPRIME
  • Cell types:
    1. Name: C666-1
      Description: Nasopharyngeal carcinoma cells also known as c666-1; C6661
    2. Name: HEK-293T
      Description: Human embryonic kidney Fibroblast
      Known as: HEK293T, 293T
    3. Name: NP460hTert
      Description: Telomerase immortalized cell line also known as NP460 hTert; NP460
    4. Name: NP69SV40T
      Description: Human transformed cell line also known as NP69.  

Abstract

Despite the improvement in locoregional control of nasopharyngeal carcinoma (NPC), distant metastasis (DM), and chemoresistance persist as major causes of mortality. This study identified a novel role for miR-449b, an overexpressed gene in a validated four-miRNA signature for NPC DM, leading to chemoresistance via the direct targeting of transforming growth factor beta-induced (TGFBI). In vitro shRNA-mediated downregulation of TGFBI induced phosphorylation of PTEN and AKT, increasing cisplatin resistance. Conversely, the overexpression of TGFBI sensitized the NPC cells to cisplatin. In NPC patients treated with concurrent chemoradiotherapy (CRT), the overall survival (OS) was significantly inversely correlated with miR-449b, and directly correlated with both TGFBI mRNA and protein expression, as assessed by RNA sequencing and immunohistochemistry (IHC). Mechanistically, co-immunoprecipitation demonstrated that TGFBI competes with pro-TGFbeta1 for integrin receptor binding. Decreased TGFBI led to increased pro-TGFbeta1 activation and TGFbeta1 canonical/noncanonical pathway-induced cisplatin resistance. Thus, overexpression of miR-449b decreases TGFBI, thereby altering the balance between TGFBI and pro-TGFbeta1, revealing a novel mechanism of chemoresistance in NPC.

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