SAM68 promotes tumorigenesis in lung adenocarcinoma by regulating metabolic conversion via PKM alternative splicing

• Published in: Theranostics 2021-01, Vol.11 (7), p.3359-3375
• Main Authors: Zhu, Song, Chen, Weiping, Wang, Jizhong, Qi, Ling, Pan, Huilin, Feng, Zhengfu, Tian, Dongbo
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Signal Transducing - antagonists & inhibitors; Adaptor Proteins, Signal Transducing - genetics; Adaptor Proteins, Signal Transducing - metabolism; Adenocarcinoma of Lung - genetics; Adenocarcinoma of Lung - metabolism; Adenocarcinoma of Lung - mortality; Adenocarcinoma of Lung - pathology; Alternative Splicing; Animals; Breast cancer; Carcinogenesis - genetics; Carcinogenesis - metabolism; Carcinogenesis - pathology; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cell growth; Cell Line, Tumor; Cell Movement; Cell Proliferation; CRISPR; DNA-Binding Proteins - antagonists & inhibitors; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Exons; Gene expression; Gene Expression Regulation, Neoplastic; Glycolysis - genetics; Heterogeneous Nuclear Ribonucleoprotein A1 - genetics; Heterogeneous Nuclear Ribonucleoprotein A1 - metabolism; Humans; Isoenzymes - genetics; Isoenzymes - metabolism; Kinases; Lung cancer; Lung Neoplasms - genetics; Lung Neoplasms - metabolism; Lung Neoplasms - mortality; Lung Neoplasms - pathology; Medical prognosis; Membrane Proteins - genetics; Membrane Proteins - metabolism; Metabolism; Metastasis; Mice; Mice, Inbred NOD; Neoplasm Recurrence, Local - genetics; Neoplasm Recurrence, Local - metabolism; Neoplasm Recurrence, Local - mortality; Neoplasm Recurrence, Local - pathology; Oxidative Phosphorylation; Phosphorylation; Proteins; Research Paper; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism; RNA-Binding Proteins - antagonists & inhibitors; RNA-Binding Proteins - genetics; RNA-Binding Proteins - metabolism; Signal Transduction; Survival Analysis; Thyroid Hormone-Binding Proteins; Thyroid Hormones - genetics; Thyroid Hormones - metabolism; Tumor Burden; Tumorigenesis; Xenograft Model Antitumor Assays
• ISSN: 1838-7640; 1838-7640
• DOI: 10.7150/THNO.51360

A metabolic "switch" from oxidative phosphorylation to glycolysis provides tumor cells with energy and biosynthetic substrates, thereby promoting tumorigenesis and malignant progression. However, the mechanisms controlling this metabolic switch in tumors is not entirely clear. Clinical specimens were used to determine the effect of SAM68 on lung adenocarcinoma (LUAD) tumorigenesis and metastasis, and mouse models and molecular biology assays were performed to elucidate the function and underlying mechanisms and . mRNA levels were higher in LUAD tissue than in normal lung tissue, indicating that expression is upregulated in LUAD. Patients with LUAD with (n = 257) had a higher frequency of tumor recurrence ( 0.025) and recurrence-free survival ( 0.013) than did those with (n = 257). Patients with mRNA levels (n = 257) were at a higher risk for cancer-related death ( 0.006), and had shorter overall survival ( 0.044) than did those with . SAM68 promotes tumorigenesis and metastasis of LUAD cells and by regulating the cancer metabolic switch. SAM68 drives cancer metabolism by mediating alternative splicing of pyruvate kinase (PKM) pre-mRNAs, and promoting the formation of PKM2. Mechanistically, SAM68 increased the binding of the splicing repressor hnRNP A1 to exon 9 of , thereby enhancing PKM2 isoform formation and PKM2-dependent aerobic glycolysis and tumorigenesis. SAM68 promotes LUAD cell tumorigenesis and cancer metabolic programming via binding of the 351-443 aa region of SAM68 to the RGG motif of hnRNP A1, driving hnRNP A1-dependent splicing, contributing to increased oncogene PKM2 isoform formation and inhibition of PKM1 isoform formation. SAM68 is therefore a promising therapeutic target for the treatment of LUAD.