Double mutant P53 (N340Q/L344R) promotes hepatocarcinogenesis through upregulation of Pim1 mediated by PKM2 and LncRNA CUDR

Reprogramming of Glucose Metabolism for Revisiting Hepatocellular Carcinoma Resistance to Transcatheter Hepatic Arterial Chemoembolization

Hepatocellular carcinoma (HCC) is recognized globally as one of the most lethal tumors, presenting a significant menace to patients' lives owing to its exceptional aggressiveness and tendency to recur. Transcatheter hepatic arterial chemoembolization (TACE) therapy, as a first-line treatment option for patients with advanced HCC, has been proven effective. However, it is disheartening that nearly 40 % of patients exhibit resistance to this therapy. Consequently, this review delves into the metabolic aspects of glucose metabolism to explore the underlying mechanisms behind TACE treatment resistance and to propose potentially fruitful therapeutic strategies. The ultimate objective is to present novel insights for the development of personalized treatment methods targeting HCC.

Epigenetic modifications involving ncRNAs in digestive system cancers: focus on histone modification

In recent years, epigenetic modifications have been strongly linked to tumor development, with histone modifications representing a key epigenetic mechanism. In addition, non-coding RNAs (ncRNAs) play a critical role in regulating cancer-related pathways. The abnormal interaction between histone modifications and ncRNAs, both pivotal epigenetic regulators, has been widely observed across various cancer types. Here, we systematically explore the molecular mechanisms through which histone modifications and ncRNAs contribute in the pathogenesis of digestive system cancers, and aberrant ncRNA-mediated histone modifications manipulate various biological behaviors of tumor cells including proliferation, migration, angiogenesis, etc. In addition, we provide new insights into diagnostic, prognostic markers, therapeutic targets and chemoradiation resistance for digestive system cancers from the epigenetic perspective.

Involvement of lncRNAs in the regulation of aerobic glycolysis in hepatocellular carcinoma: Main functions, regulatory mechanisms and potential therapeutic implications (Review)

Even under aerobic conditions, tumor cells can reprogram their metabolism to preferentially metabolize glucose into lactic acid. This abnormal metabolic pattern, known as the 'Warburg' effect or aerobic glycolysis, promotes cancer progression. Long non‑coding RNAs (lncRNAs) are RNAs that are >200 nucleotides in length and do not have protein‑coding capabilities. However, these RNAs play a key role in tumor development. There is increasing evidence to indicate that lncRNAs regulate glucose metabolism in tumor cells by affecting metabolic enzymes and some signaling pathways, thereby regulating the occurrence and progression of hepatocellular carcinoma (HCC). Therefore, it is crucial to understand which lncRNAs play a regulatory role in HCC glycolysis and to determine the related molecular mechanisms. The present review summarized and discussed the functions of lncRNAs, focusing on the regulatory mechanisms of lncRNAs in the process of glycolysis in HCC. In addition, the present review suggests the importance of lncRNAs as future therapeutic targets for antitumor cell metabolism.

Telomerase-related advances in hepatocellular carcinoma: A bibliometric and visual analysis

BACKGROUND

As a critical early event in hepatocellular carcinogenesis, telomerase activation might be a promising and critical biomarker for hepatocellular carcinoma (HCC) patients, and its function in the genesis and treatment of HCC has gained much attention over the past two decades.

AIM

To perform a bibliometric analysis to systematically assess the current state of research on HCC-related telomerase.

METHODS

The Web of Science Core Collection and PubMed were systematically searched to retrieve publications pertaining to HCC/telomerase limited to "articles" and "reviews" published in English. A total of 873 relevant publications related to HCC and telomerase were identified. We employed the Bibliometrix package in R to extract and analyze the fundamental information of the publications, such as the trends in the publications, citation counts, most prolific or influential writers, and most popular journals; to screen for keywords occurring at high frequency; and to draw collaboration and cluster analysis charts on the basis of coauthorship and co-occurrences. VOSviewer was utilized to compile and visualize the bibliometric data.

RESULTS

A surge of 51 publications on HCC/telomerase research occurred in 2016, the most productive year from 1996 to 2023, accompanied by the peak citation count recorded in 2016. Up to December 2023, 35226 citations were made to all publications, an average of 46.6 citations to each paper. The United States received the most citations (n = 13531), followed by China (n = 7427) and Japan (n = 5754). In terms of national cooperation, China presented the highest centrality, its strongest bonds being to the United States and Japan. Among the 20 academic institutions with the most publications, ten came from China and the rest of Asia, though the University of Paris Cité, Public Assistance-Hospitals of Paris, and the National Institute of Health and Medical Research (INSERM) were the most prolific. As for individual contributions, Hisatomi H, Kaneko S, and Ide T were the three most prolific authors. Kaneko S ranked first by H-index, G-index, and overall publication count, while Zucman-Rossi J ranked first in citation count. The five most popular journals were the World Journal of Gastroenterology, Hepatology, Journal of Hepatology, Oncotarget, and Oncogene, while Nature Genetics, Hepatology, and Nature Reviews Disease Primers had the most citations. We extracted 2293 keywords from the publications, 120 of which appeared more than ten times. The most frequent were HCC, telomerase and human telomerase reverse transcriptase (hTERT). Keywords such as mutational landscape, TERT promoter mutations, landscape, risk, and prognosis were among the most common issues in this field in the last three years and may be topics for research in the coming years.

CONCLUSION

Our bibliometric analysis provides a comprehensive overview of HCC/telomerase research and insights into promising upcoming research.

Role of long non-coding RNAs in metabolic reprogramming of gastrointestinal cancer cells

Metabolic reprogramming, which is recognized as a hallmark of cancer, refers to the phenomenon by which cancer cells change their metabolism to support their increased biosynthetic demands. Tumor cells undergo substantial alterations in metabolic pathways, such as glycolysis, oxidative phosphorylation, pentose phosphate pathway, tricarboxylic acid cycle, fatty acid metabolism, and amino acid metabolism. Latest studies have revealed that long non-coding RNAs (lncRNAs), a group of non-coding RNAs over 200 nucleotides long, mediate metabolic reprogramming in tumor cells by regulating the transcription, translation and post-translational modification of metabolic-related signaling pathways and metabolism-related enzymes through transcriptional, translational, and post-translational modifications of genes. In addition, lncRNAs are closely related to the tumor microenvironment, and they directly or indirectly affect the proliferation and migration of tumor cells, drug resistance and other processes. Here, we review the mechanisms of lncRNA-mediated regulation of glucose, lipid, amino acid metabolism and tumor immunity in gastrointestinal tumors, aiming to provide more information on effective therapeutic targets and drug molecules for gastrointestinal tumors.

Long Non-coding RNA UCA1a Promotes Proliferation via PKM2 in Cervical Cancer

Cervical cancer is a common malignancy that affects women worldwide. The long non-coding RNA (lncRNA) urothelial cancer-associated 1a (UCA1a) is reported to be significantly upregulated in cervical cancer. However, the exact role of UCA1a in cervical cancer remains unknown. This study aimed to identify two core promoter regions in UCA1a, which are essential for CEBPA-dependent transcription and FOXL1-, FOXL4-, and FOXL6-dependent activation, respectively. RNA sequencing results showed that overexpression of UCA1a resulted in extensive changes in the gene expression profile of HeLa cells, especially in the signaling pathway that regulates tumorgenesis. Mass spectrometry assay was conducted to show that pyruvate kinase M2 (PKM2) was a UCA1a-interacting protein. The 400 ~ 800 nt long region of UCA1a at the 5' end and the A1B domain of PKM2 were critical for the UCA1a-PKM2 interaction. Functional assays were performed to show that PKM2 was sufficient and necessary for UCA1a-induced proliferation of HeLa cells, which was partly due to the regulating of nuclear translocation and stabilization of PKM2. These findings provide a novel mechanism for UCA1a to regulate Hela cells by ubiquitination degradation of PKM2 and suggest that UCA1a may play a key role in the progression of cervical cancer.

Influence of Long Non-Coding RNA in the Regulation of Cancer Stem Cell Signaling Pathways

Over the past two decades, cancer stem cells (CSCs) have emerged as an immensely studied and experimental topic, however a wide range of questions concerning the topic still remain unanswered; in particular, the mechanisms underlying the regulation of tumor stem cells and their characteristics. Understanding the cancer stem-cell signaling pathways may pave the way towards a better comprehension of these mechanisms. Signaling pathways such as WNT, STAT, Hedgehog, NOTCH, PI3K/AKT/mTOR, TGF-β, and NF-κB are responsible not only for modulating various features of CSCs but also their microenvironments. Recently, the prominent roles of various non-coding RNAs such as small non-coding RNAs (sncRNAs) and long non-coding RNAs (lncRNAs) in developing and enhancing the tumor phenotypes have been unfolded. This review attempts to shed light on understanding the influence of long non- coding RNAs in the modulation of various CSC-signaling pathways and its impact on the CSCs and tumor properties; highlighting the protagonistic and antagonistic roles of lncRNAs.

Long non‑coding RNAs interact with RNA‑binding proteins to regulate genomic instability in cancer cells (Review)

Genomic instability, a feature of most cancers, contributes to malignant cell transformation and cancer progression due to the accumulation of genetic alterations. Genomic instability is reflected at numerous levels, from single nucleotide to the chromosome levels. However, the exact molecular mechanisms and regulators of genomic instability in cancer remain unclear. Growing evidence indicates that the binding of long non-coding RNAs (lncRNAs) to protein chaperones confers a variety of regulatory functions, including managing of genomic instability. The aim of the present review was to examine the roles of mitosis, telomeres, DNA repair, and epigenetics in genomic instability, and the mechanisms by which lncRNAs regulate them by binding proteins in cancer cells. This review contributes to our understanding of the role of lncRNAs and genomic instability in cancer and can potentially provide entry points and molecular targets for cancer therapies.

Heterochromatin Protein 1: A Multiplayer in Cancer Progression

Dysregulation of epigenetic mechanisms as well as genomic mutations contribute to the initiation and progression of cancer. In addition to histone code writers, including histone lysine methyltransferase (KMT), and histone code erasers, including histone lysine demethylase (KDM), histone code reader proteins such as HP1 are associated with abnormal chromatin regulation in human diseases. Heterochromatin protein 1 (HP1) recognizes histone H3 lysine 9 methylation and broadly affects chromatin biology, such as heterochromatin formation and maintenance, transcriptional regulation, DNA repair, chromatin remodeling, and chromosomal segregation. Molecular functions of HP1 proteins have been extensively studied, although their exact roles in diseases require further study. Here, we comprehensively review the studies that have revealed the altered expression of HP1 and its functions in tumorigenesis. In particular, the distinctive effects of each HP1 subtype, namely HP1α, HP1β, and HP1γ, have been thoroughly explored in various cancer types. We also highlight how HP1 can serve as a potential biomarker for cancer prognosis and therapeutic target for cancer patients.

Insulin promotes hepatocarcinoma tumorigenesis by up-regulating PKM2 expression

Insulin, as a growth factor, can increase the risk of certain types of cancer. The present study showed that insulin promoted the proliferation of hepatocellular carcinoma cells in vitro and in vivo through pyruvate kinase M2 (PKM2), which is a rate-limiting enzyme in the process of glycolysis. Moreover, the expression of PKM2 was up-regulated by insulin at the posttranslational level in a nuclear orphan receptor TR3-dependent manner. In addition, insulin could enhance the interaction between PKM2 and TR3 and protect PKM2 from degradation. Our results identified a specific mechanism of insulin affecting cancer metabolism and thus promoting cancer progression, and they contribute to a better understanding of the observation that insulin is linked to an increased cancer risk under hyperinsulinemic conditions.

Non-coding RNAs rewire cancer metabolism networks

Non-coding RNAs (ncRNAs) are functional RNAs with limited or no protein-coding ability. These interact with their target molecules and participate in the precise regulation of disease development. Metabolic reprogramming is a hallmark in cancer, and is considered essential in meeting increased macromolecular biosynthesis and energy generation of tumors. Recent studies have revealed the involvement of ncRNAs in several metabolic regulations of cancer through direct modulation of metabolic enzyme activities or participation of metabolism-related signaling pathways. Elucidation of how ncRNAs regulate metabolic reprogramming of cancers has opened up a novel intention to understand the mechanism of metabolic rewiring and also the opportunities of utilizing ncRNA-based therapeutics for targeting the metabolism in cancer treatment.

Crosstalk of lncRNA and Cellular Metabolism and Their Regulatory Mechanism in Cancer

The imbalanced regulation of metabolic homeostasis and energy production is highly associated with inflammation, tumor growth, metastasis and cancer progression. Both glycolysis and oxidative phosphorylation maintain metabolic homeostasis and energy production in cells. Long noncoding RNAs (lncRNAs) are a class of non-protein-coding transcripts longer than 200 nucleotides. Furthermore, lncRNAs can function as either tumor suppressors or oncogenes in cancer. Dysregulated lncRNAs reportedly regulate cancer hallmarks such as tumor growth, metabolism and metastasis. Accordingly, uncovering the interaction between lncRNAs and cellular metabolism has become a necessity when attempting to identify effective therapeutic and preventive strategies in cancer progression. This review summarizes important knowledge of the actions of known lncRNAs-mediated cancer metabolism.

The molecular mechanisms of LncRNA-correlated PKM2 in cancer metabolism

Reprogrammed metabolism is an important hallmark of cancer cells. Pyruvate kinase (PK) is one of the major rate-limiting enzymes in glucose metabolism. The M2 isoform of PK (PKM2), is considered to be an important marker of metabolic reprogramming and one of the key enzymes. Recently, through the continuous development of genome-wide analysis and functional studies, accumulating evidence has demonstrated that long non-coding RNAs (LncRNAs) play vital regulatory roles in cancer progression by acting as either potential oncogenes or tumor suppressors. Furthermore, several studies have shown that up-regulation of PKM2 in cancer tissues is associated with LncRNAs expression and patient survival. Thus, scientists have begun to unveil the mechanism of LncRNA-associated PKM2 in cancer metabolic progression. Based on these novel findings, in this mini-review, we summarize the detailed molecular mechanisms of LncRNA related to PKM2 in cancer metabolism. We expect that this work will promote a better understanding of the molecular mechanisms of PKM2, and provide a profound potential for targeting PKM2 to treat tumors.

PKM2, function and expression and regulation

Pyruvate kinase (PK), as one of the key enzymes for glycolysis, can encode four different subtypes from two groups of genes, although the M2 subtype PKM2 is expressed mainly during embryonic development in normal humans, and is closely related to tissue repair and regeneration, with the deepening of research, the role of PKM2 in tumor tissue has received increasing attention. PKM2 can be aggregated into tetrameric and dimeric forms, PKM2 in the dimer state can enter the nuclear to regulate gene expression, the transformation between them can play an important role in tumor cell energy supply, epithelial-mesenchymal transition (EMT), invasion and metastasis and cell proliferation. We will use the switching effect of PKM2 in glucose metabolism as the entry point to expand and enrich the Warburg effect. In addition, PKM2 can also regulate each other with various proteins by phosphorylation, acetylation and other modifications, mediate the different intracellular localization of PKM2 and then exert specific biological functions. In this paper, we will illustrate each of these points.

Elevated telomere dysfunction in cells containing the African-centric Pro47Ser cancer-risk variant of TP53

Subtelomeric transcription and chromatin can have a significant impact on telomere repeat maintenance and chromosome stability. We have previously found that tumor suppressor protein p53 (TP53) can bind to retrotransposon-like elements in a majority of human subtelomeres to regulate TERRA transcription and telomeric histone acetylation in response to DNA damage. TP53 also prevents the accumulation of γH2AX DNA-damage signaling at telomeres. We now show that the inherited TP53 polymorphism Pro47Ser (hereafter S47), which is enriched in populations of African descent, is associated with elevated marks of telomere dysfunction. We found that human and mouse cells carrying the S47 variant show increased γH2AX DNA-damage signals at telomeres, as well as reduced TERRA transcription and subtelomeric histone acetylation in response to DNA damage stress. Cell-lines containing inducible genes for P47 or S47 versions of p53, as well mouse embryo fibroblasts (MEFs) reconstituted with human p53, showed elevated telomere-induced DNA damage foci and metaphase telomere signal loss in cells with S47. Human lymphoblastoid cell lines (LCLs) derived from individuals homozygous for S47, show increased accumulation of subtelomeric γH2AX and unstable telomere repeats in response to DNA damage relative to age matched LCLs homozygous for P47. Furthermore, LCLs with S47 had reduced replicative lifespan. These studies indicate that the naturally occurring S47 variant of p53 can affect telomeric chromatin, telomere repeat stability, and replicative capacity. We discuss the potential evolutionary significance of the S47 variant to African populations with respect to telomere regulation and the implications for inherited health disparities.

miR675 Accelerates Malignant Transformation of Mesenchymal Stem Cells by Blocking DNA Mismatch Repair

miR675 is highly expressed in several human tumor tissues and positively regulates cell progression. Herein, we demonstrate that miR675 promotes malignant transformation of human mesenchymal stem cells. Mechanistically, we reveal that miR675 enhances the expression of the polyubiquitin-binding protein p62. Intriguingly, P62 competes with SETD2 to bind histone H3 and then significantly reduces SETD2-binding capacity to substrate histone H3, triggering drastically the reduction of three methylation on histone H3 36th lysine (H3K36me3). Thereby, the H3K36me3-hMSH6-SKP2 triplex complex is significantly decreased. Notably, the ternary complex’s occupancy capacity on chromosome is absolutely reduced, preventing it from DNA damage repair. By virtue of the reductive degradation ability of SKP2 for aging histone H3.3 bound to mismatch DNA, the aging histone H3.3 repair is delayed. Therefore, the mismatch DNA escapes from repair, triggering the abnormal expression of several cell cycle-related genes and causing the malignant transformation of mesenchymal stem cells. These observations strongly suggest understanding the novel functions of miR675 will help in the development of novel therapeutic approaches in a broad range of cancer types.

MicroRNA 675 cooperates PKM2 to aggravate progression of human liver cancer stem cells induced from embryonic stem cells

Both miR675 and pyruvate kinase M2 (PKM2) contribute to malignant progression of tumor, but its functions in liver cancer stem cells remain unclear. Herein, our findings indicate that miR675 plus PKM2 strongly promotes the growth of liver cancer stem cells. Mechanistically, miR675 plus PKM2 enhances the transcriptional activity of SUV39h2. On the other hand, the excessive SUV39h2 binds to more substrate histone H3, triggering an increase of tri-methylation of histone H3 on the ninth lysine. Furthermore, the tri-methylation of histone 3 on the ninth lysine (H3K9me3)-heterochromatin protein 1 alpha (HP1α) complex is increased when the complex occupancy ability on the C-myc promoter region is raised, recruiting CREB, P300, and RNApolII to the special position that results in C-myc high abundance. Therefore, miR675 plus PKM2 triggered the upregulation of C-myc by increasing the interaction between H3K9me3 and HP1α. Understanding the signaling pathways that miR675 plus PKM2 epigenetically possesses during the malignant transformation of liver cancer stem cells will contribute to more effective liver cancer therapies.

Emerging roles of long non-coding RNAs in tumor metabolism

Compared with normal cells, tumor cells display distinct metabolic characteristics. Long non-coding RNAs (lncRNAs), a large class of regulatory RNA molecules with limited or no protein-coding capacity, play key roles in tumorigenesis and progression. Recent advances have revealed that lncRNAs play a vital role in cell metabolism by regulating the reprogramming of the metabolic pathways in cancer cells. LncRNAs could regulate various metabolic enzymes that integrate cell malignant transformation and metabolic reprogramming. In addition to the known functions of lncRNAs in regulating glycolysis and glucose homeostasis, recent studies also implicate lncRNAs in amino acid and lipid metabolism. These observations reveal the high complexity of the malignant metabolism. Elucidating the metabolic-related functions of lncRNAs will provide a better understanding of the regulatory mechanisms of metabolism and thus may provide insights for the clinical development of cancer diagnostics, prognostics and therapeutics.

PKM2, a potential target for regulating cancer

Aberrated glucose metabolism is a key future of cancer cells. Unlike normal cells, tumor cells favor glycolysis even in the presence of sufficient oxygen. Pyruvate kinase (PK), a key glucose metabolic enzyme, converts phosphoenolpyruvate (PEP) to pyruvate by transferring the high-energy phosphate group to adenosine diphosphate (ADP) to produce adenosine triphosphate (ATP). Pyruvate kinase M2 (PKM2), one of the four isozyme of PK, which universally expressed in rapidly proliferating cells such as embryonic cells and cancer cells. Recent years, more and more research suggested PKM2 plays a crucial role in cancer progression through both metabolic and non-metabolic pathways. On the one hand, the middle product of glycolysis, such as amino acids, nucleotides, lipids is necessary to rapid growth of cancer cells. On the other hand, PKM2 supports tumor growth through regulating the expression of gene that involved in cell proliferation, migration and apoptosis. In this article, we review the recent advances to further understand the regulation and function of PKM2 in tumorigenesis. Given its multiple effects on cancer, PKM2 may be a potential target for cancer diagnosis and treatment.

p53 and metabolism: from mechanism to therapeutics

The tumor cell changes itself and its microenvironment to adapt to different situations, including action of drugs and other agents targeting tumor control. Therefore, metabolism plays an important role in the activation of survival mechanisms to keep the cell proliferative potential. The Warburg effect directs the cellular metabolism towards an aerobic glycolytic pathway, despite the fact that it generates less adenosine triphosphate than oxidative phosphorylation; because it creates the building blocks necessary for cell proliferation. The transcription factor p53 is the master tumor suppressor; it binds to more than 4,000 sites in the genome and regulates the expression of more than 500 genes. Among these genes are important regulators of metabolism, affecting glucose, lipids and amino acids metabolism, oxidative phosphorylation, reactive oxygen species (ROS) generation and growth factors signaling. Wild-type and mutant p53 may have opposing effects in the expression of these metabolic genes. Therefore, depending on the p53 status of the cell, drugs that target metabolism may have different outcomes and metabolism may modulate drug resistance. Conversely, induction of p53 expression may regulate differently the tumor cell metabolism, inducing senescence, autophagy and apoptosis, which are dependent on the regulation of the PI3K/AKT/mTOR pathway and/or ROS induction. The interplay between p53 and metabolism is essential in the decision of cell fate and for cancer therapeutics.

HistoneH3 demethylase JMJD2A promotes growth of liver cancer cells through up-regulating miR372

Changes in histone lysine methylation status have been observed during cancer formation. JMJD2A protein is a demethylase that is overexpressed in several tumors. Herein, our results demonstrate that JMJD2A accelerates malignant progression of liver cancer cells in vitro and in vivo. Mechanistically, JMJD2A promoted the expression and mature of pre-miR372 epigenetically. Notably, miR372 blocks the editing of 13th exon-introns-14th exon and forms a novel transcript(JMJD2AΔ) of JMJD2A. In particular, JMJD2A inhibited P21(WAF1/Cip1) expression by decreasing H3K9me3 dependent on JMJD2AΔ. Thereby, JMJD2A could enhance Pim1 transcription by suppressing P21(WAF1/Cip1). Furthermore, through increasing the expression of Pim1, JMJD2A could facilitate the interaction among pRB, CDK2 and CyclinE which prompts the transcription and translation of oncogenic C-myc. Strikingly, JMJD2A may trigger the demethylation of Pim1. On the other hand, Pim1 knockdown and P21(WAF1/Cip1) overexpression fully abrogated the oncogenic function of JMJD2A. Our observations suggest that JMJD2A promotes liver cancer cell cycle progress through JMJD2A-miR372-JMJD2AΔ-P21WAF1/Cip1-Pim1-pRB-CDK2-CyclinE-C-myc axis. This study elucidates a novel mechanism for JMJD2A in liver cancer cells and suggests that JMJD2A can be used as a novel therapeutic targets of liver cancer.

Long noncoding RNA MEG3 suppresses liver cancer cells growth through inhibiting β-catenin by activating PKM2 and inactivating PTEN

Maternally expressed gene 3 (MEG3) encodes an lncRNA which is suggested to function as a tumor suppressor and has been showed to involve in a variety of cancers. Herein, our findings demonstrate that MEG3 inhibits the malignant progression of liver cancer cells in vitro and in vivo. Mechanistically, MEG3 promotes the expression and maturition of miR122 which targets PKM2. Therefore, MEG3 decreases the expression and nuclear location of PKM2 dependent on miR122. Furthermore, MEG3 also inhibits CyclinD1 and C-Myc via PKM2 in liver cancer cells. On the other hand, MEG3 promotes β-catenin degradation through ubiquitin-proteasome system dependent on PTEN. Strikingly, MEG3 inhibits β-catenin activity through PKM2 reduction and PTEN increase. Significantly, we also found that excessive β-catenin abrogated the effect of MEG3 in liver cancer. In conclusion, our study for the first time demonstrates that MEG3 acts as a tumor suppressor by negatively regulating the activity of the PKM2 and β-catenin signaling pathway in hepatocarcinogenesis and could provide potential therapeutic targets for the treatment of liver cancer.

Non-coding RNAs in the reprogramming of glucose metabolism in cancer

Proliferating cancer cells reprogram their metabolic circuitry to thrive in an environment deficient in nutrients and oxygen. Cancer cells exhibit a higher rate of glucose metabolism than normal somatic cells, which is achieved by switching from oxidative phosphorylation to aerobic glycolysis to meet the energy and metabolites demands of tumour progression. This phenomenon, which is known as the Warburg effect, has generated renewed interest in the process of glucose metabolism reprogramming in cancer cells. Several regulatory pathways along with glycolytic enzymes are responsible for the emergence of glycolytic dependence. Non-coding (nc)RNAs are a class of functional RNA molecules that are not translated into proteins but regulate target gene expression. NcRNAs have been shown to be involved in various biological processes, including glucose metabolism. In this review, we describe the regulatory role of ncRNAs-specifically, microRNAs and long ncRNAs-in the glycolytic switch and propose that ncRNA-based therapeutics can be used to inhibit the process of glucose metabolism reprogramming in cancer cells.

Role of long non-coding RNAs in glucose metabolism in cancer

Long-noncoding RNAs (lncRNAs) are a group of transcripts that are longer than 200 nucleotides and do not code for proteins. However, this class of RNAs plays pivotal regulatory roles. The mechanism of their action is highly complex. Mounting evidence shows that lncRNAs can regulate cancer onset and progression in a variety of ways. They can not only regulate cancer cell proliferation, differentiation, invasion and metastasis, but can also regulate glucose metabolism in cancer cells through different ways, such as by directly regulating the glycolytic enzymes and glucose transporters (GLUTs), or indirectly modulating the signaling pathways. In this review, we summarized the role of lncRNAs in regulating glucose metabolism in cancer, which will help understand better the pathogenesis of malignant tumors. The understanding of the role of lncRNAs in glucose metabolism may help provide new therapeutic targets and novel diagnostic and prognosis markers for human cancer.

Long noncoding RNA SchLAH suppresses metastasis of hepatocellular carcinoma through interacting with fused in sarcoma

Emerging evidence has indicated that deregulation of long non‐coding RNAs (lncRNAs) can contribute to the progression and metastasis of human cancer, including hepatocellular carcinoma (HCC). However, the roles of most lncRNAs in HCC remain largely unknown. Here we found a long noncoding RNA termed SchLAH (seven chromosome locus associated with HCC; also called BC035072) was generally downregulated in HCC. Low expression of SchLAH was significantly correlated with shorter overall survival of HCC patients. In vitro and in vivo assays indicated that overexpression of SchLAH inhibited the migration and lung metastasis of HCC cells. Knockdown of SchLAH by siRNA pool promoted the migration of HCC cells. RNA pull‐down and RNA immunoprecipitation assays demonstrated SchLAH physically interacted with fused in sarcoma (FUS). PCR array analysis showed that RhoA and Rac1 were the downstream effector molecules of SchLAH during HCC metastasis. Knockdown of FUS rescued the mRNA levels of RhoA and Rac1 that were repressed by SchLAH. These results suggest that SchLAH may suppress the metastasis of HCC cells by interacting with FUS, which indicates potential of SchLAH for the prognosis and treatment of HCC.

Clinical, cellular, and bioinformatic analyses reveal involvement of WRAP53 overexpression in carcinogenesis of lung adenocarcinoma

Lung cancer, of which non-small cell lung cancer accounts for 80%, remains a leading cause of cancer-related mortality and morbidity worldwide. Our study revealed that the expression of WD repeat containing antisense to P53 (WRAP53) is higher in lung-adenocarcinoma specimens than in specimens from adjacent non-tumor tissues. The prevalence of WRAP53 overexpression was significantly higher in patients with tumor larger than 3.0 cm than in patients with tumor smaller than 3.0 cm. The depletion of WRAP53 inhibits the proliferation of lung-adenocarcinoma A549 and SPC-A-1 cells via G1/S cell-cycle arrest. Several proteins interacting with WRAP53 were identified through co-immunoprecipitation and liquid chromatography/mass spectrometry. These key proteins indicated previously undiscovered functions of WRAP53. These observations strongly suggested that WRAP53 should be considered a promising target in the prevention or treatment of lung adenocarcinoma.

Mutant p53 and mTOR/PKM2 regulation in cancer cells

Mutations of TP53 gene are the most common feature in aggressive malignant cells. In addition to the loss of the tumor suppressive role of wild-type p53, hotspot mutant p53 isoforms display oncogenic proprieties notoriously referred as gain of functions (GOFs) which result in chemoresistance to therapies, genomic instability, aberrant deregulation of cell cycle progression, invasiveness and enhanced metastatic potential, and finally, in patient poor survival rate. The identification of novel functional oncogenic pathways regulated by mutant p53 represent and intriguing topic for emerging therapies against a broad spectrum of cancer types bearing mutant TP53 gene. Mammalian target of rapamycin (mTOR), as well as pyruvate kinase isoform M2 (PKM2) are master regulators of cancer growth, metabolism, and cell proliferation. Herein, we report that GOF mutant R175H and R273H p53 proteins trigger PKM2 phosphorylation on Tyr 105 through the involvement of mTOR signaling. Our data, together with the newly discovered connection between mutant p53 and mTOR stimulation, raise important implications for the potential therapeutic use of synthetic drugs inhibiting mTOR/PKM2 axis in cancer cells bearing mutant TP53 gene. We further hypothesize that mTOR/PKM2 pathway stimulation serves to sustain the oncogenic activity of mutant p53 through both the enhancement of chemoresistance and of aerobic glycolysis of cancer cells. © 2016 IUBMB Life, 68(9):722-726, 2016.