Overexpression of NNT-AS1 Activates TGF-β Signaling to Decrease Tumor CD4 Lymphocyte Infiltration in Hepatocellular...

Area of Science:

• Oncology
• Molecular Biology
• Immunology

Background:

• Hepatocellular carcinoma (HCC) is a major global health concern.
• Tumor immune evasion, often mediated by signaling pathways like TGF-β, is a key challenge in HCC treatment.
• Long noncoding RNAs (lncRNAs) are increasingly recognized for their roles in cancer development and progression.

Purpose of the Study:

• To investigate the molecular mechanism of Nicotinamide nucleotide transhydrogenase-antisense RNA1 (NNT-AS1) in HCC.
• To explore how NNT-AS1 contributes to tumor immune evasion by activating the TGF-β signaling pathway and affecting tumor-infiltrating lymphocytes (TILs).

Main Methods:

• Quantification of NNT-AS1 expression in HCC tissues using RNAscope and RT-qPCR.
• Assessment of TGF-β signaling proteins and CD4 T lymphocytes via immunohistochemistry (IHC).
• In vitro studies in HCC cell lines (HepG2, Huh7) to determine NNT-AS1's effect on TGF-β pathway activation.

Main Results:

• NNT-AS1 was significantly overexpressed in HCC tissues (P = 0.0001, P = 0.0003).
• Higher NNT-AS1 levels correlated with shorter overall survival in HCC patients (P = 0.0402).
• NNT-AS1 inhibition decreased TGF-β signaling components (TGF-β, TGFBR1, SMAD5) and reduced CD4 T cell infiltration in HCC.

Conclusions:

• NNT-AS1 is a significant oncogenic lncRNA in HCC, associated with poor prognosis.
• NNT-AS1 promotes HCC immune evasion by activating the TGF-β signaling pathway.
• This activation leads to impaired CD4 T cell infiltration, highlighting NNT-AS1 as a potential therapeutic target.