Hepatocellular carcinoma (HCC) is a common type of primary liver cancer and is considered the third leading cause of cancer-related deaths worldwide. The high aggressiveness and resistance to therapies exhibited by HCC present significant challenges to global public health. As the primary metabolic organ in the human body, the liver undergoes substantial metabolic reprogramming during carcinogenesis, affecting various metabolic pathways including those involved in carbohydrates, lipids, and amino acids. Notably, disruptions in amino acid metabolism play a critical role in the initiation and progression of HCC, helping to sustain its malignant characteristics. This review aims to provide an in-depth analysis of the alterations observed in aromatic amino acids metabolism, branched chain amino acids (BCAAs) metabolism, glutamine metabolism, and other amino acid metabolism processes, including serine, arginine, and methionine, along with the expression patterns of associated metabolic enzymes. Furthermore, it discusses potential therapeutic approaches and their clinical relevance, offering insights and strategies for improving HCC diagnosis and treatment in the future.
Background: Interferons (IFNs) are key cytokines that drive immune responses against infections and cancer, yet few therapies have successfully leveraged IFN signaling for cancer treatment. Long noncoding RNAs (lncRNAs) are emerging as promising therapeutic candidates, but their roles in immune modulation remain largely unexplored. Here, we functionally characterize a breast cancer-associated lncRNA, BRRIAR, which primes the IFN signaling pathway in specific cancer contexts and represents a potential therapeutic strategy for estrogen receptor-positive (ER+) breast cancer.
Methods: BRRIAR expression and subcellular localization were examined using qPCR, in situ hybridization, single-cell RNA sequencing and spatial transcriptomics. BRRIAR target genes were identified through CRISPR interference, chromatin interaction assays and ChIP sequencing. Mechanistic studies in ER + breast cancer cells included CRISPR-Cas9 genome-wide screens, RNA sequencing, RNA pull-down followed by mass spectrometry, proliferation assays and Western blotting. The therapeutic potential of BRRIAR was evaluated via intratumoral delivery of lipid nanoparticle-encapsulated BRRIAR in ER + breast cancer xenograft models. Immune activation was assessed using flow cytometry and cytokine profiling of human peripheral blood mononuclear cells (PBMCs).
Results: We demonstrate that BRRIAR is a key target gene at the 3p26 breast cancer risk region. Primarily expressed in ER + breast tumors, BRRIAR acts both in cis and in trans. Nuclear BRRIAR regulates BHLHE40 expression in cis through chromatin interactions, while cytoplasmic BRRIAR binds in trans to the pattern recognition receptor RIG-I, priming IFN signaling. Overexpression of BRRIAR RNA triggers RIG-I signaling, inducing IFN responses, drives rapid, dose-dependent apoptosis of ER + breast cancer cells in vitro and in vivo, and promotes immune activation in human PBMCs.
Conclusions: These findings establish lncRNAs as key regulators of tumor immunity and uncover a critical link between genetic risk, lncRNAs, cancer immunosurveillance and breast cancer development, positioning BRRIAR as a promising lncRNA-based RIG-I activator for ER + breast cancer therapy.

