The molecular mechanisms of LncRNA-correlated PKM2 in cancer metabolism

Biological roles of SLC16A1-AS1 lncRNA and its clinical impacts in tumors

Recent studies have increasingly highlighted the aberrant expression of SLC16A1-AS1 in a variety of tumor types, where it functions as either an oncogene or a tumor suppressor in the pathogenesis of different cancers. The expression levels of SLC16A1-AS1 have been found to significantly correlate with clinical features and the prognosis of cancer patients. Furthermore, SLC16A1-AS1 modulates a range of cellular functions, including proliferation, migration, and invasion, through its interactions with diverse molecules and signaling pathways. This review examines the latest evidence regarding the role of SLC16A1-AS1 in the progression of various tumors and explores its potential clinical applications as a novel prognostic and diagnostic biomarker. Our comprehensive review aims to deepen the understanding of SLC16A1-AS1's multifaceted role in oncology, underscoring its potential as a significant biomarker and therapeutic target.

Apatinib weakens proliferation, migration, invasion, and angiogenesis of thyroid cancer cells through downregulating pyruvate kinase M2

Thyroid cancer (TC) is the most frequent malignancy of the endocrine system. Apatinib, as an anti-angiogenic agent, has been applied in the therapy of several cancers. However, the function and mechanism of Apatinib in TC have not been clearly elucidated. After processing with Apatinib alone or combined PKM2 overexpression plasmids, cell proliferation, migration, and invasion were analyzed by EdU staining, CCK-8, wound healing, and Transwell. Meanwhile. HUVECs were incubated with the conditioned medium prepared from cell culture medium, and tube formation and VEGFR2 expression in HUVECs were examined using tube formation and immunofluorescence (IF) assays. Besides, we established a nude mouse xenograft model by lentivirus-mediated PKM2 shRNAs, and tested the growth of tumors; the pathological structure was analyzed with H&E staining. And the expressions of N-cadherin, Vimentin, E-cadherin, PKM2, VEGFA, VEGFR2, and Ki67 were determined by immunohistochemistry or Western blot. Apatinib could prominently suppress proliferation, migration, invasion, and HUVEC tube formation in SW579 and TPC-1 cells. Besides, we discovered that Apatinib had a significant inhibitory role on the expression of pyruvate kinase M2 (PKM2) in TC cells. And PKM2 overexpression also could notably reverse Apatinib-mediated inhibition of TC progression. Moreover, PKM2 shRNAs were applied to TC xenografts, resulting in significant reduction in tumor volume and suppression of angiogenesis-related protein expression. In summary, Apatinib has a regulatory role in TC progression, and Apatinib can block cancer cell angiogenesis by downregulating PKM2. This will provide a theoretical basis for therapy of TC.

Positioning determines function: Wandering PKM2 performs different roles in tumor cells

Short for pyruvate kinase M2 subtype, PKM2 can be said of all-round player that is notoriously known for its metabolic involvement in glycolysis. Holding a dural role as a metabolic or non-metabolic (kinase) enzyme, PKM2 has drawn extensive attention over its biological roles implicated in tumor cells, including proliferation, migration, invasion, metabolism, and so on. wandering PKM2 can be transboundary both intracellularly and extracellularly. Specifically, PKM2 can be nuclear, cytoplasmic, mitochondrial, exosomal, or even circulate within the body. Importantly, PKM2 can function as an RNA-binding protein (RBP) to self-support its metabolic function. Despite extensive investigations or reviews available surrounding the biological roles of PKM2 from different angles in tumor cells, little has been described regarding some novel role of PKM2 that has been recently found, including, for example, acting as RNA-binding protein, protection of Golgi apparatus, and remodeling of microenvironment, and so forth. Given these findings, in this review, we summarize the recent advancements made in PKM2 research, mainly from non-metabolic respects. By the way, PKM1, another paralog of PKM2, seems to have been overlooked or under-investigated since its discovery. Some recent discoveries made about PKM1 are also preliminarily mentioned and discussed.

Non-metabolic enzyme function of PKM2 in hepatocellular carcinoma: A review

Hepatocellular carcinoma (HCC) is one of the most malignant tumors with the highest incidence and mortality in the world, causing a serious burden on society. Pyruvate kinase M2 (PKM2) is one of the principal metabolic enzymes involved in glycolysis. Studies have shown that PKM2 is highly expressed in HCC and can be translocated to the nucleus, where it interacts with various transcription factors and proteins such as hypoxia-inducible factor-1α, sterol regulatory element-binding protein 1a, signal transducer and activator of transcription 3, nuclear factor erythroid 2-like 2 and histone H3, exerting non-metabolic enzyme functions to regulate the cell cycle, proliferation, apoptosis, immune escape, migration, and invasion, as well as HCC angiogenesis and tumor microenvironment. This review is focused on the recent progress of PKM2 interacting with various transcription factors and proteins affecting the onset and development of HCC, as well as natural drugs and noncoding RNA impacting diverse biological functions of liver cancer cells by regulating PKM2 non-metabolic enzyme functions, thereby providing valuable directions for the prognosis improvement and molecular targeted therapy of HCC in the future.

LncRNA LINC01833 is a Prognostic Biomarker and Correlates with Immune Infiltrates in Patients with Lung Adenocarcinoma by Integrated Bioinformatics Analysis

Due to the absence of accurate tools for early detection and successful treatment, lung adenocarcinoma (LUAD) is one of the most aggressive tumors with high morbidity and mortality globally. It is absolutely necessary to investigate the process behind its development and search for new biomarkers that could aid in the early detection of LUAD. There is a correlation between the immune microenvironment of the tumor and the prognosis of lung cancer as well as the efficacy of immunotherapy. Long noncoding RNAs (lncRNAs) have been identified as potential prognostic biomarkers linked to immunological activities. In this study, we identified 1 downregulated lncRNA and 76 upregulated lncRNAs in LUAD samples from TCGA datasets. Among the 77 dysregulated lncRNAs, our attention focused on lncRNA LINC01833 (LINC01833). When compared with nontumor specimens, the level of expression of LINC01833 was shown to be significantly elevated in LUAD samples. In addition, the data of the ROC study revealed that LUAD patients with high LINC01833 expression had an AUC value of 0.840 (95% confidence interval: 0.804 to 0.876). There was a correlation between high LINC01833 expression and an advanced clinical stage. Patients who had a high expression of LINC01833 were shown to have a lower overall survival rate (p < 0.001) and a lower disease-specific survival rate (p = 0.004) in comparison to patients who were in the low LINC01833 group, according to the data on survival. In addition, the results of the multivariate analysis revealed that high LINC01833 expression was an independent predictor of poor survival in LUAD. Moreover, the immune analysis revealed that we found that the expression of LINC01833 was positively associated with Th2 cells, aDC, and Tgd, while negatively associated with Mast cells, Tcm, Eosinophils, iDC, DC, Tem, Th17 cells, and pDC. Overall, our data point to the possibility that the unique lncRNA LINC01833 might be employed as a diagnostic and prognostic marker, and as a result, it has a significant impact on clinical practice.

LncCCAT1 interaction protein PKM2 upregulates SREBP2 phosphorylation to promote osteosarcoma tumorigenesis by enhancing the Warburg effect and lipogenesis

Pyruvate kinase M2 (PKM2) plays an important role in the consumption of glucose and the production of lactic acid, the striking feature of cancer metabolism. The association of PKM2 with osteosarcoma (OS) has been reported but its role in OS has yet to be elucidated. To study this, PKM2‑bound RNAs in HeLa cells, a type of cancer cells widely used in the study of molecular function and mechanism, were obtained. Peak calling analysis revealed that PKM2 binds to long noncoding RNAs (lncRNAs), which are associated with cancer pathogenesis and development. Validation of the PKM2‑lncRNA interaction in the human OS cell line revealed that lncRNA colon cancer associated transcript‑1 (lncCCAT1) interacted with PKM2, which upregulated the phosphorylation of sterol regulatory element‑binding protein 2 (SREBP2). These factors promoted the Warburg effect, lipogenesis, and OS cell growth. PKM2 appears to be a key regulator in OS by binding to lncCCAT1. This further extends the biological functions of PKM2 in tumorigenesis and makes it a novel potential therapeutic for OS.

Multiple functions of pyruvate kinase M2 in various cell types

Glucose metabolism is a mechanism by which energy is produced in form of adenosine triphosphate (ATP) by mitochondria and precursor metabolites are supplied to enable the ultimate enrichment of mature metabolites in the cell. Recently, glycolytic enzymes have been shown to have unconventional but important functions. Among these enzymes, pyruvate kinase M2 (PKM2) plays several roles including having conventional metabolic enzyme activity, and also being a transcriptional regulator and a protein kinase. Compared with the closely related PKM1, PKM2 is highly expressed in cancer cells and embryos, whereas PKM1 is dominant in mature, differentiated cells. Posttranslational modifications such as phosphorylation and acetylation of PKM2 change its cellular functions. In particular, PKM2 can translocate to the nucleus, where it regulates the transcription of many target genes. It is notable that PKM2 also acts as a protein kinase to phosphorylate several substrate proteins. Besides cancer cells and embryonic cells, astrocytes also highly express PKM2, which is crucial for lactate production via expression of lactate dehydrogenase A (LDHA), while mature neurons predominantly express PKM1. The lactate produced in cancer cells promotes tumor progress and that in astrocytes can be supplied to neurons and may act as a major source for neuronal ATP energy production. Thereby, we propose that PKM2 along with its different posttranslational modifications has specific purposes for a variety of cell types, performing unique functions.