Identification of pyruvate kinase type M2 as potential oncoprotein in squamous cell carcinoma of tongue through microRNA profiling

Interplay between miRNA expression and glucose metabolism in oral squamous cell carcinoma

OBJECTIVE

Given the urgent need for improved diagnostic and therapeutic strategies in oral squamous cell carcinoma (OSCC), this review aims to explore the intricate interplay between OSCC and alterations in glucose metabolism, with a particular focus on the pivotal role of microRNAs (miRNAs) in this context.

MATERIAL AND METHODS

Data were extracted from a vast literature survey by using PubMed, Embase, and Web of Science search engines with relevant keywords.

RESULTS

In OSCC, miRNAs exert regulatory control over the expression of genes involved in glucose metabolism pathways. Dysregulation of specific miRNAs has been implicated in the modulation of key glycolytic enzymes and glucose transporters, intracellular signaling cascades, and interaction with transcription factors, all of which collectively affect glucose uptake and glycolysis, contributing significantly to the observed metabolic alterations in OSCC cells.

CONCLUSION

A comprehensive understanding of these intricate molecular interactions holds significant promise for the development of targeted therapeutic interventions and refined diagnostic approaches to treat OSCC patients.

Unraveling the role of miRNAs in the diagnosis, progression, and drug resistance of oral cancer

Oral cancer (OC) is a widely observed neoplasm on a global scale. Over time, there has been an increase in both its fatality and incidence rates. Oral cancer metastasis is a complex process that involves a number of cellular mechanisms, including invasion, migration, proliferation, and escaping from malignant tissue through either lymphatic or vascular channels. MicroRNAs (miRNAs) are a crucial class of short non-coding RNAs recognized as significant modulators of diverse cellular processes and exert a pivotal influence on the carcinogenesis pathway, functioning either as tumor suppressors or as oncogenes. It has been shown that microRNAs (miRNAs) have a role in metastasis at several stages, including epithelial-mesenchymal transition, migration, invasion, and colonization. This regulation is achieved by targeting key genes involved in these pathways by miRNAs. This paper aims to give a contemporary analysis of OC, focusing on its molecular genetics. The current literature and emerging advancements in miRNA dysregulation in OC are thoroughly examined. This project would advance OC diagnosis, prognosis, therapy, and therapeutic implications.

miR-133b Promotes Esophageal Squamous Cell Carcinoma Metastasis

Background

Evaluation of biological changes at the molecular level has important clinical implications for improving the survival rate of esophageal squamous cell carcinoma (ESCC). Therefore, we plan to analyze and elucidate the expression of microRNA-133b (miR-133b), M2 pyruvate kinase (PKM2), and signal transducer and activator of transcription 3 (STAT3) in ESCC and their associated clinicopathological significance.

Methods

The 72 patients with ESCC were selected as the experimental study group. Normal adjacent tissues (NAT) were matched as the control group. In this study, in situ hybridization was used to detect the expression of miR-133b in ESCC, and tissue expressions of PKM2 and STAT3 were detected by immunohistochemistry, and literature review was conducted.

Results

Studies had shown that the positive expression of miR-133b in NAT was significantly higher than that in ESCC (χ2 = 9.007, P = .003). PKM2 and STAT3 in ESCC had a significantly higher positive expression levels than those of NAT (χ2 = 56.523, P = .000; χ2 = 72.939, P = .000). From correlation analysis, there was a negative correlation between miR-133b and PKM2(r = -0.515, P < .001), a negative correlation between miR-133b and STAT3(r = -0.314, P = .007), and a positive correlation between PKM2 and STAT3(r = 0.771, P < .001).

Conclusions

In ESCC, our study demonstrated that downregulation of miR-133b and upregulation of PKM2 and STAT3. We predict that miR-133b may inhibit the STAT3 pathway by downregulating PKM2.

Non-Coding RNAs in Oral Cancer: Emerging Roles and Clinical Applications

Oral cancer (OC) is among the most prevalent cancers in the world. Certain geographical areas are disproportionately affected by OC cases due to the regional differences in dietary habits, tobacco and alcohol consumption. However, conventional therapeutic methods do not yield satisfying treatment outcomes. Thus, there is an urgent need to understand the disease process and to develop diagnostic and therapeutic strategies for OC. In this review, we discuss the role of various types of ncRNAs in OC, and their promising clinical implications as prognostic or diagnostic markers and therapeutic targets. MicroRNA (miRNA), long ncRNA (lncRNA), circular RNA (circRNA), PIWI-interacting RNA (piRNA), and small nucleolar RNA (snoRNA) are the major ncRNA types whose involvement in OC are emerging. Dysregulated expression of ncRNAs, particularly miRNAs, lncRNAs, and circRNAs, are linked with the initiation, progression, as well as therapy resistance of OC via modulation in a series of cellular pathways through epigenetic, transcriptional, post-transcriptional, and translational modifications. Differential expressions of miRNAs and lncRNAs in blood, saliva or extracellular vesicles have indicated potential diagnostic and prognostic importance. In this review, we have summarized all the promising aspects of ncRNAs in the management of OC.

Functional importance of glucose transporters and chromatin epigenetic factors in Glioblastoma Multiforme (GBM): possible therapeutics

Glioblastoma Multiforme (GBM) is an aggressive brain cancer affecting glial cells and is chemo- and radio-resistant. Glucose is considered the most vital energy source for cancer cell proliferation. During metabolism, hexose molecules will be transported into the cells via transmembrane proteins known as glucose transporter (GLUT). Among them, GLUT-1 and GLUT-3 play pivotal roles in glucose transport in GBM. Knockdown studies have established the role of GLUT-1, and GLUT-3 mediated glucose transport in GBM cells, providing insight into GLUT-mediated cancer signaling and cancer aggressiveness. This review focussed on the vital role of GLUT-1 and GLUT-3 proteins, which regulate glucose transport. Recent studies have identified the role of GLUT inhibitors in effective cancer prevention. Several of them are in clinical trials. Understanding and functional approaches towards glucose-mediated cell metabolism and chromatin epigenetics will provide valuable insights into the mechanism of cancer aggressiveness, cancer stemness, and chemo-resistance in Glioblastoma Multiforme (GBM). This review summarizes the role of GLUT inhibitors, micro-RNAs, and long non-coding RNAs that aid in inhibiting glucose uptake by the GBM cells and other cancer cells leading to the identification of potential therapeutic, prognostic as well as diagnostic markers. Furthermore, the involvement of epigenetic factors, such as microRNAs, in regulating glycolytic genes was demonstrated.

The paradigm of miRNA and siRNA influence in Oral-biome

Short nucleotide sequences like miRNA and siRNA have attracted a lot of interest in Oral-biome investigations. miRNA is a small class of non-coding RNA that regulates gene expression to provide effective regulation of post-transcription. On contrary, siRNA is 21-25 nucleotide dsRNA impairing gene function post-transcriptionally through inhibition of mRNA for homologous dependent gene silencing. This review highlights the application of miRNA in oral biome including oral cancer, dental implants, periodontal diseases, gingival fibroblasts, oral submucous fibrosis, radiation-induced oral mucositis, dental Pulp, and oral lichenoid disease. Moreover, we have also discussed the application of siRNA against the aforementioned disease along with the impact of miRNA and siRNA to the various pathways and molecular effectors pertaining to the dental diseases. The influence of upregulation and downregulation of molecular effector post-treatment with miRNA and siRNA and their impact on the clinical setting has been elucidated. Thus, the mentioned details on application of miRNA and siRNA will provide a novel gateway to the scholars to not only mitigate the long-lasting issue in dentistry but also develop new theragnostic approaches.

MicroRNAs as Regulators of Cancer Cell Energy Metabolism

To adapt to the tumor environment or to escape chemotherapy, cancer cells rapidly reprogram their metabolism. The hallmark biochemical phenotype of cancer cells is the shift in metabolic reprogramming towards aerobic glycolysis. It was thought that this metabolic shift to glycolysis alone was sufficient for cancer cells to meet their heightened energy and metabolic demands for proliferation and survival. Recent studies, however, show that cancer cells rely on glutamine, lipid, and mitochondrial metabolism for energy. Oncogenes and scavenging pathways control many of these metabolic changes, and several metabolic and tumorigenic pathways are post-transcriptionally regulated by microRNA (miRNAs). Genes that are directly or indirectly responsible for energy production in cells are either negatively or positively regulated by miRNAs. Therefore, some miRNAs play an oncogenic role by regulating the metabolic shift that occurs in cancer cells. Additionally, miRNAs can regulate mitochondrial calcium stores and energy metabolism, thus promoting cancer cell survival, cell growth, and metastasis. In the electron transport chain (ETC), miRNAs enhance the activity of apoptosis-inducing factor (AIF) and cytochrome c, and these apoptosome proteins are directed towards the ETC rather than to the apoptotic pathway. This review will highlight how miRNAs regulate the enzymes, signaling pathways, and transcription factors of cancer cell metabolism and mitochondrial calcium import/export pathways. The review will also focus on the metabolic reprogramming of cancer cells to promote survival, proliferation, growth, and metastasis with an emphasis on the therapeutic potential of miRNAs for cancer treatment.

The Connection between MicroRNAs and Oral Cancer Pathogenesis: Emerging Biomarkers in Oral Cancer Management

Oral cancer is a common human malignancy that still maintains an elevated mortality rate despite scientific progress. Tumorigenesis is driven by altered gene expression patterns of proto-oncogenes and tumor-suppressor genes. MicroRNAs, a class of short non-coding RNAs involved in gene regulation, seem to play important roles in oral cancer development, progression, and tumor microenvironment modulation. As properties of microRNAs render them stable in diverse liquid biopsies, together with their differential expression signature in cancer cells, these features place microRNAs at the top of promising biomarkers for diagnostic and prognostic values. In this review, we highlight eight expression levels and functions of the most relevant microRNAs involved in oral cancer development, progression, and microenvironment sustainability. Furthermore, we emphasize the potential of using these small RNA species as non-invasive biomarkers for the early detection of oral cancerous lesions. Conclusively, we highlight the perspectives and limitations of microRNAs as novel diagnostic tools, as well as therapeutic models.

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.

Oxygen sensing, mitochondrial biology and experimental therapeutics for pulmonary hypertension and cancer

The homeostatic oxygen sensing system (HOSS) optimizes systemic oxygen delivery. Specialized tissues utilize a conserved mitochondrial sensor, often involving NDUFS2 in complex I of the mitochondrial electron transport chain, as a site of pO₂-responsive production of reactive oxygen species (ROS). These ROS are converted to a diffusible signaling molecule, hydrogen peroxide (H₂O₂), by superoxide dismutase (SOD2). H₂O₂ exits the mitochondria and regulates ion channels and enzymes, altering plasma membrane potential, intracellular Ca²⁺ and Ca²⁺-sensitization and controlling acute, adaptive, responses to hypoxia that involve changes in ventilation, vascular tone and neurotransmitter release. Subversion of this O₂-sensing pathway creates a pseudohypoxic state that promotes disease progression in pulmonary arterial hypertension (PAH) and cancer. Pseudohypoxia is a state in which biochemical changes, normally associated with hypoxia, occur despite normal pO₂. Epigenetic silencing of SOD2 by DNA methylation alters H₂O₂ production, activating hypoxia-inducible factor 1α, thereby disrupting mitochondrial metabolism and dynamics, accelerating cell proliferation and inhibiting apoptosis. Other epigenetic mechanisms, including dysregulation of microRNAs (miR), increase pyruvate dehydrogenase kinase and pyruvate kinase muscle isoform 2 expression in both diseases, favoring uncoupled aerobic glycolysis. This Warburg metabolic shift also accelerates cell proliferation and impairs apoptosis. Disordered mitochondrial dynamics, usually increased mitotic fission and impaired fusion, promotes disease progression in PAH and cancer. Epigenetic upregulation of dynamin-related protein 1 (Drp1) and its binding partners, MiD49 and MiD51, contributes to the pathogenesis of PAH and cancer. Finally, dysregulation of intramitochondrial Ca²⁺, resulting from impaired mitochondrial calcium uniporter complex (MCUC) function, links abnormal mitochondrial metabolism and dynamics. MiR-mediated decreases in MCUC function reduce intramitochondrial Ca²⁺, promoting Warburg metabolism, whilst increasing cytosolic Ca²⁺, promoting fission. Epigenetically disordered mitochondrial O₂-sensing, metabolism, dynamics, and Ca²⁺ homeostasis offer new therapeutic targets for PAH and cancer. Promoting glucose oxidation, restoring the fission/fusion balance, and restoring mitochondrial calcium regulation are promising experimental therapeutic strategies.

The link among microbiota, epigenetics, and disease development

The microbiome is a community of various microorganisms that inhabit or live on the skin of humans/animals, sharing the body space with their hosts. It is a sort of complex ecosystem of trillions of commensals, symbiotic, and pathogenic microorganisms, including trillions of bacteria, archaea, protozoa, fungi, and viruses. The microbiota plays a role in the health and disease status of the host. Their number, species dominance, and viability are dynamic. Their long-term disturbance is usually accompanied by serious diseases such as metabolic disorders, cardiovascular diseases, or even cancer. While epigenetics is a term that refers to different stimuli that induce modifications in gene expression patterns without structural changes in the inherited DNA sequence, these changes can be reversible or even persist for several generations. Epigenetics can be described as cell memory that stores experience against internal and external factors. Results from multiple institutions have contributed to the role and close interaction of both microbiota and epigenetics in disease induction. Understanding the mechanisms of both players enables a better understanding of disease induction and development and also opens the horizon to revolutionary therapeutic approaches. The present review illustrates the roles of diet, microbiome, and epigenetics in the induction of several chronic diseases. In addition, it discusses the application of epigenetic data to develop diagnostic biomarkers and therapeutics and evaluate their safety for patients. Understanding the interaction among all these elements enables the development of innovative preventive/therapeutic approaches for disease control.

The Role of PKM2 in Metabolic Reprogramming: Insights into the Regulatory Roles of Non-Coding RNAs

Pyruvate kinase is a key regulator in glycolysis through the conversion of phosphoenolpyruvate (PEP) into pyruvate. Pyruvate kinase exists in various isoforms that can exhibit diverse biological functions and outcomes. The pyruvate kinase isoenzyme type M2 (PKM2) controls cell progression and survival through the regulation of key signaling pathways. In cancer cells, the dimer form of PKM2 predominates and plays an integral role in cancer metabolism. This predominance of the inactive dimeric form promotes the accumulation of phosphometabolites, allowing cancer cells to engage in high levels of synthetic processing to enhance their proliferative capacity. PKM2 has been recognized for its role in regulating gene expression and transcription factors critical for health and disease. This role enables PKM2 to exert profound regulatory effects that promote cancer cell metabolism, proliferation, and migration. In addition to its role in cancer, PKM2 regulates aspects essential to cellular homeostasis in non-cancer tissues and, in some cases, promotes tissue-specific pathways in health and diseases. In pursuit of understanding the diverse tissue-specific roles of PKM2, investigations targeting tissues such as the kidney, liver, adipose, and pancreas have been conducted. Findings from these studies enhance our understanding of PKM2 functions in various diseases beyond cancer. Therefore, there is substantial interest in PKM2 modulation as a potential therapeutic target for the treatment of multiple conditions. Indeed, a vast plethora of research has focused on identifying therapeutic strategies for targeting PKM2. Recently, targeting PKM2 through its regulatory microRNAs, long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) has gathered increasing interest. Thus, the goal of this review is to highlight recent advancements in PKM2 research, with a focus on PKM2 regulatory microRNAs and lncRNAs and their subsequent physiological significance.

The pivotal role of MicroRNAs in glucose metabolism in cancer

Cancer cells are able to undergo aerobic glycolysis and metabolize glucose to lactate instead of oxidative phosphorylation, which is known as Warburg effect. Accumulating evidence has revealed that microRNAs regulate cancer cell metabolism, which manifest a higher rate of glucose metabolism. Various signaling pathways along with glycolytic enzymes are responsible for the emergence of glycolytic dependence. MicroRNAs are a class of non-coding RNAs that are not translated into proteins but regulate target gene expression or in other words function pre-translationally and post-transcriptionally. MicroRNAs have been shown to be involved in various biological processes, including glucose metabolism via targeting major transcription factors, enzymes, oncogenes or tumor suppressors alongside the oncogenic signaling pathways. In this review, we describe the regulatory role of microRNAs of cancer cell glucose metabolism, including in the glucose uptake, glycolysis, tricarboxylic acid cycle and several signaling pathways and further suggest that microRNA-based therapeutics can be used to inhibit the process of glucose metabolism reprogramming in cancer cells and thus suppressing cancer progression.

microRNAs deregulation in head and neck squamous cell carcinoma

Head and neck (HN) squamous cell carcinoma (SCC) is the eighth most common human cancer worldwide. Besides tobacco and alcohol consumption, genetic and epigenetic alterations play an important role in HNSCC occurrence and progression. microRNAs (miRNAs) are small noncoding RNAs that regulate cell cycle, proliferation, development, differentiation, and apoptosis by interfering in gene expression. Expression profiling of miRNAs showed that some miRNAs are upregulated or downregulated in tumor cells when compared with the normal cells. The present review focuses on the role of miRNAs deregulations in HNSCC, enrolled in risk, development, outcome, and therapy sensitivity. Moreover, the influence of single nucleotide variants in miRNAs target sites, miRNAs seed sites, and miRNAs-processing genes in HNSCC was also revised. Due to its potential for cancer diagnosis, progression, and as a therapeutic target, miRNAs may bring new perspectives in HNSCC understanding and therapy, especially for those patients with no or insufficient treatment options.

Sequenced Combinations of Cisplatin and Selected Phytochemicals towards Overcoming Drug Resistance in Ovarian Tumour Models

In the present study, cisplatin, artemisinin, and oleanolic acid were evaluated alone, and in combination, on human ovarian A2780, A2780^ZD0473R, and A2780^cisR cancer cell lines, with the aim of overcoming cisplatin resistance and side effects. Cytotoxicity was assessed by MTT reduction assay. Combination index (CI) values were used as a measure of combined drug effect. MALDI TOF/TOF MS/MS and 2-DE gel electrophoresis were used to identify protein biomarkers in ovarian cancer and to evaluate combination effects. Synergism from combinations was dependent on concentration and sequence of administration. Generally, bolus was most synergistic. Moreover, 49 proteins differently expressed by 2 ≥ fold were: CYPA, EIF5A1, Op18, p18, LDHB, P4HB, HSP7C, GRP94, ERp57, mortalin, IMMT, CLIC1, NM23, PSA3,1433Z, and HSP90B were down-regulated, whereas hnRNPA1, hnRNPA2/B1, EF2, GOT1, EF1A1, VIME, BIP, ATP5H, APG2, VINC, KPYM, RAN, PSA7, TPI, PGK1, ACTG and VDAC1 were up-regulated, while TCPA, TCPH, TCPB, PRDX6, EF1G, ATPA, ENOA, PRDX1, MCM7, GBLP, PSAT, Hop, EFTU, PGAM1, SERA and CAH2 were not-expressed in A2780^cisR cells. The proteins were found to play critical roles in cell cycle regulation, metabolism, and biosynthetic processes and drug resistance and detoxification. Results indicate that appropriately sequenced combinations of cisplatin with artemisinin (ART) and oleanolic acid (OA) may provide a means to reduce side effects and circumvent platinum resistance.

Regulation of Glycolysis by Non-coding RNAs in Cancer: Switching on the Warburg Effect

The “Warburg effect” describes the reprogramming of glucose metabolism away from oxidative phosphorylation toward aerobic glycolysis, and it is one of the hallmarks of cancer cells. Several factors can be involved in this process, but in this review, the roles of non-coding RNAs (ncRNAs) are highlighted in several types of human cancer. ncRNAs, including microRNAs, long non-coding RNAs, and circular RNAs, can all affect metabolic enzymes and transcription factors to promote glycolysis and modulate glucose metabolism to enhance the progression of tumors. In particular, the 5′-AMP-activated protein kinase (AMPK) and the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathways are associated with alterations in ncRNAs. A better understanding of the roles of ncRNAs in the Warburg effect could ultimately lead to new therapeutic approaches for suppressing cancer.

Noncoding RNAs: the shot callers in tumor immune escape

Immunotherapy, designed to exploit the functions of the host immune system against tumors, has shown considerable potential against several malignancies. However, the utility of immunotherapy is heavily limited due to the low response rate and various side effects in the clinical setting. Immune escape of tumor cells may be a critical reason for such low response rates. Noncoding RNAs (ncRNAs) have been identified as key regulatory factors in tumors and the immune system. Consequently, ncRNAs show promise as targets to improve the efficacy of immunotherapy in tumors. However, the relationship between ncRNAs and tumor immune escape (TIE) has not yet been comprehensively summarized. In this review, we provide a detailed account of the current knowledge on ncRNAs associated with TIE and their potential roles in tumor growth and survival mechanisms. This review bridges the gap between ncRNAs and TIE and broadens our understanding of their relationship, providing new insights and strategies to improve immunotherapy response rates by specifically targeting the ncRNAs involved in TIE.

TUG1/miR-133b/CXCR4 axis regulates cisplatin resistance in human tongue squamous cell carcinoma

Background

Long noncoding RNA taurine upregulated 1 (TUG1) has been reported to play an important role in human cancers. However, little is known about the role of TUG1 in drug resistance and its mechanism in tongue squamous cell carcinoma (TSCC).

Methods

Twenty-one cisplatin-sensitive or resistant TSCC patients were enrolled in this study. Cisplatin-resistant cells (SCC25/CDDP and CAL27/CDDP) were used for experiments in vitro. Transfection was performed using Lipofectamine 2000 transfection reagent. The levels of TUG1, microRNA-133b (miR-133b) and cysteine-X-cysteine chemokine receptor 4 (CXCR4) were measured by quantitative real-time polymerase chain reaction or western blot. The cisplatin resistance was investigated by cell viability, transwell invasion and apoptosis assays. The interactions among TUG1, miR-133b and CXCR4 were evaluated by luciferase reporter assay and RNA immunoprecipitation. Murine xenograft model was established using the stably transfected CAL27/CDDP cells.

Results

TUG1 expression was elevated in cisplatin-resistant TSCC tissues and cells compared with that in sensitive group and its knockdown inhibited cisplatin resistance to SCC25/CDDP and CAL27/CDDP cells. miR-133b was targeted via TUG1 and its overexpression suppressed cisplatin resistance. Moreover, CXCR4 was a target of miR-133b. CXCR4 silence repressed cisplatin resistance, which was reversed by miR-133b knockdown. The level of CXCR4 protein was decreased by inhibition of TUG1 and recuperated by miR-133b knockdown. Besides, interference of TUG1 attenuated tumor growth by regulating miR-133b and CXCR4 in vivo.

Conclusion

Downregulation of TUG1 impeded cisplatin resistance in TSCC-resistant cells by mediating miR-133b and CXCR4, indicating TUG1 as a promising target for TSCC chemotherapy.

miR-145 promotes miR-133b expression through c-myc and DNMT3A-mediated methylation in ovarian cancer cells

Ovarian cancer presents as malignant tumors in the female reproductive system with high mortality. MicroRNAs are involved in the progression of ovarian cancer; however, the regulatory relationship among miRs remains unclear. In our study, we verified that both miR-145 and miR-133b messenger RNA (mRNA) levels in ovarian cancer tissues were lower than in normal ovarian tissues, and their mRNA level in serum of patients with ovarian cancer was reduced. We demonstrated miR-145 targeted c-myc, and c-myc interacted physically with DNMT3A in ovarian cancer cells. We confirmed that c-myc recruited DNMT3A to the miR-133b promoter. miR-133b overexpression also inhibited target gene PKM2 expression along with the Warburg effect. Our results indicate that miR-145 inhibited the Warburg effect through miR-133b/PKM2 pathways, which may improve approaches to ovarian cancer diagnosis and treatment.

Oncogenic gene RGC-32 is a direct target of miR-26b and facilitates tongue squamous cell carcinoma aggressiveness through EMT and PI3K/AKT signalling

Growing data have recognized the significance of Response Gene to Complement (RGC)-32 in numerous tumour developments. Notwithstanding, the functional role and underlying mechanism of it in tongue squamous cell carcinoma (TSCC) remain enigmatic. Here, to identify the impact of RGC-32 in TSCC, its expression in multiple TSCC cells was measured and loss-of-function experiments in cell lines were performed to illuminate the function of it induced TSCC progression, via si-RNA knockdown, CCK-8, colony formation, wound-healing, transwell, flow cytometry and western blot assays. To clarify potential mechanism, expressions of hallmarks in epithelial-mesenchymal transition (EMT) process and PI3K/AKT signalling were assessed, and the upstream miR regulator of RGC-32 was predicted and verified by applying bioinformatic approaches and dual-luciferase reporter assay, respectively. Finally, the rescue experiments were applied to better elucidate the effect of miR-26b/RGC-32 axis in TSCC behaviours. As a result, RGC-32 was upregulated in TSCC cells and knocking down of it abrogated cell proliferation, trans-migration and invasion, whilst promoted apoptosis in TSCC, which was regulated through repressing EMT and inactivation of PI3K/AKT signalling. Subsequently, miR-26b was predicted and identified as an upstream regulator of RGC-32, and the pro-tumorigenic effect of RGC-32 was reversed by miR-26b overexpression. Collectively, our results demonstrated that RGC-32 facilitated TSCC progression, which was modulated by activations of PI3K/AKT pathway and EMT process, and reduction of its negative regulator of miR-26b. These findings highlight a novel role of miR-26b/RGC-32 axis in TSCC and underlying mechanism, encouraging a potent usage in TSCC treatment. SIGNIFICANCE OF THE STUDY: We first uncovered that Response Gene to Complement-32 played a significantly pro-tumorigenic role in tongue squamous cell carcinoma (TSCC), which was closely regulated by downregulation of miR-26b and activations of epithelial-mesenchymal transition process and PI3K/AKT signalling. These findings contribute to better understand the molecular mechanism in carcinogenesis of TSCC, and shed some light on promising strategy for TSCC therapeutics.

MicroRNAs in Tumor Cell Metabolism: Roles and Therapeutic Opportunities

Dysregulated metabolism is a common feature of cancer cells and is considered a hallmark of cancer. Altered tumor-metabolism confers an adaptive advantage to cancer cells to fulfill the high energetic requirements for the maintenance of high proliferation rates, similarly, reprogramming metabolism confers the ability to grow at low oxygen concentrations and to use alternative carbon sources. These phenomena result from the dysregulated expression of diverse genes, including those encoding microRNAs (miRNAs) which are involved in several metabolic and tumorigenic pathways through its post-transcriptional-regulatory activity. Further, the identification of key actionable altered miRNA has allowed to propose novel targeted therapies to modulated tumor-metabolism. In this review, we discussed the different roles of miRNAs in cancer cell metabolism and novel miRNA-based strategies designed to target the metabolic machinery in human cancer.

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.

Micromanaging aerobic respiration and glycolysis in cancer cells

BACKGROUND

Cancer cells possess a common metabolic phenotype, rewiring their metabolic pathways from mitochondrial oxidative phosphorylation to aerobic glycolysis and anabolic circuits, to support the energetic and biosynthetic requirements of continuous proliferation and migration. While, over the past decade, molecular and cellular studies have clearly highlighted the association of oncogenes and tumor suppressors with cancer-associated glycolysis, more recent attention has focused on the role of microRNAs (miRNAs) in mediating this metabolic shift. Accumulating studies have connected aberrant expression of miRNAs with direct and indirect regulation of aerobic glycolysis and associated pathways.

SCOPE OF REVIEW

This review discusses the underlying mechanisms of metabolic reprogramming in cancer cells and provides arguments that the earlier paradigm of cancer glycolysis needs to be updated to a broader concept, which involves interconnecting biological pathways that include miRNA-mediated regulation of metabolism. For these reasons and in light of recent knowledge, we illustrate the relationships between metabolic pathways in cancer cells. We further summarize our current understanding of the interplay between miRNAs and these metabolic pathways. This review aims to highlight important metabolism-associated molecular components in the hunt for selective preventive and therapeutic treatments.

MAJOR CONCLUSIONS

Metabolism in cancer cells is influenced by driver mutations but is also regulated by posttranscriptional gene silencing. Understanding the nuanced regulation of gene expression in these cells and distinguishing rapid cellular responses from chronic adaptive mechanisms provides a basis for rational drug design and novel therapeutic strategies.

MicroRNA Regulation of Energy Metabolism to Induce Chemoresistance in Cancers

Since “Warburg effect” has been firstly uncovered in cancer cells in 1956, mounting evidence has supported the molecular mechanism underlying the energy metabolism in induced chemoresistance in cancers. MicroRNAs can mediate fine-tuning of genes in physiological process. MicroRNAs’ energy metabolic role in chemoresistance has been probed recently. In this review, we summarize 5 microRNAs in regulating glucose and lipid metabolism and other energy metabolism. They partially modulate chemoresistance to cancer treatments. Furthermore, we discuss the great therapeutic potential of metabolism-related microRNAs in novel combinatorial means to treat human cancers.

LncRNA-FEZF1-AS1 Promotes Tumor Proliferation and Metastasis in Colorectal Cancer by Regulating PKM2 Signaling

Purpose: Long non-coding RNAs (lncRNAs) play key roles in human cancers. Here, FEZF1-AS1, a highly overexpressed lncRNA in colorectal cancer, was identified by lncRNA microarrays. We aimed to explore the roles and possible molecular mechanisms of FEZF1-AS1 in colorectal cancer.Experimental Design: LncRNA expression in colorectal cancer tissues was measured by lncRNA microarray and qRT-PCR. The functional roles of FEZF1-AS1 in colorectal cancer were demonstrated by a series of in vitro and in vivo experiments. RNA pull-down, RNA immunoprecipitation and luciferase analyses were used to demonstrate the potential mechanisms of FEZF1-AS1.Results: We identified a series of differentially expressed lncRNAs in colorectal cancer using lncRNA microarrays, and revealed that FEZF1-AS1 is one of the most overexpressed. Further validation in two expanded colorectal cancer cohorts confirmed the upregulation of FEZF1-AS1 in colorectal cancer, and revealed that increased FEZF1-AS1 expression is associated with poor survival. Functional assays revealed that FEZF1-AS1 promotes colorectal cancer cell proliferation and metastasis. Mechanistically, FEZF1-AS1 could bind and increase the stability of the pyruvate kinase 2 (PKM2) protein, resulting in increased cytoplasmic and nuclear PKM2 levels. Increased cytoplasmic PKM2 promoted pyruvate kinase activity and lactate production (aerobic glycolysis), whereas FEZF1-AS1-induced nuclear PKM2 upregulation further activated STAT3 signaling. In addition, PKM2 was upregulated in colorectal cancer tissues and correlated with FEZF1-AS1 expression and patient survival.Conclusions: Together, these data provide mechanistic insights into the regulation of FEZF1-AS1 on both STAT3 signaling and glycolysis by binding PKM2 and increasing its stability. Clin Cancer Res; 24(19); 4808-19. ©2018 AACR.

Long non-coding RNA CASC15 promotes tongue squamous carcinoma progression through targeting miR-33a-5p

Long non-coding RNAs (lncRNAs) have gained a lot of attention because they participate in several human disorders, including tumors. This study determined the role of LncRNA CASC15 (cancer susceptibility candidate 15) in the development of tongue squamous cell carcinoma (TSCC). Here, we identified that CASC15 expression was upregulated in TSCC samples and cell lines. We showed that overexpression of CASC15 promoted cell proliferation, cycle, and migration in TSCC. In addition, we revealed that miR-33a-5p expression was downregulated in TSCC tissues and cell lines. Moreover, we showed that the expression of CASC15 was negatively related with miR-33a-5p expression in TSCC tissues. Ectopic expression of miR-33a-5p suppressed cell proliferation, cycle, and migration in TSCC. Elevated expression of CASC15 suppressed miR-33a-5p expression and promoted ZEB1 expression in SCC4 cell. Ectopic expression of CASC15 promoted TSCC cell proliferation, cycle, and migration through targeting miR-33a-5p. These results suggested that lncRNA CASC15 and miR-33a-5p might be exploited as new markers of TSCC and were potential treatment targets for TSCC patients.

Pleiotropic functions of miR107 in cancer networks

MicroRNAs are short regulatory RNAs that posttranscriptionally modulate gene expression and thus play crucial roles in controlling cancer-onset, growth, and progression processes. miR107, a highly conserved microRNA that maps to intron 5 of the PANK1 gene, contributes to the regulation of normal and tumor biological processes. Studies have reported that miR107 has oncogenic or tumor-suppressor functions in different human tumors. The pleiotropic functions of miR107 in various cancers are achieved via its targeting different genes that are involved in tumor proliferation, invasiveness, metastasis, angiogenesis, and chemotherapy-response pathways. The carcinogenicity or cancer-suppressor effects of miR107 occur in a tissue- and cell-specific manner, and the expression level of miR107 can be affected by various factors, including epigenetic and genetic factors, treatment exposure, and daily diet. A comprehensive analysis of the current literature suggests that miR107 functions as a central element in the regulation of cancer networks and can be used as a potential diagnostic and prognostic biomarker and drug target for therapeutic intervention.

Vitamin C in Cancer: A Metabolomics Perspective

There is an ongoing interest in cellular antioxidants and oxidants as well as cellular mechanisms underlying their effects. Several reports suggest that vitamin C (L-ascorbic acid) functions as a pro-oxidant with selective toxicity against specific types of tumor cells. In addition, reduced glutathione plays an emerging role in reducing oxidative stress due to xenobiotic toxins such as metals and oxidants associated with diseases such as cancer, cardiovascular disease, and stroke. High-dose intravenous vitamin C and intravenous glutathione have been used as complementary, alternative, and adjuvant medicines. Here, we review the molecular mechanisms underlying the regulation of oxidation/reduction systems, focusing on the altered metabolomics profile in cancer cells following treatment with pharmacological vitamin C. This review focuses on the role of vitamin C in energy metabolism in terms of adenosine triphosphate, cysteine, and reduced glutathione levels, affecting cancer cell death.

Metabolic signature of squamous cell carcinoma of the head and neck: Consequences of TP53 mutation and therapeutic perspectives

There is a pressing need to identify ways of sensitising squamous cell carcinomas of the head and neck (SCCHN) to the effects of current treatments, both from oncological and functional perspectives. Alteration to cellular metabolism is now widely considered a hallmark of the cancer phenotype; presents a potentially attractive therapeutic target in this regard; and as such has received renewed research interest in recent years. However, whilst metabolic disruption may occur to some degree in all tumours, there is undoubtedly heterogeneity and detailed study of individual tumour types is paramount if effective therapeutic strategies targeting metabolism are to be developed and effectively deployed. In this review we outline current understanding of altered tumour metabolism and how these adaptations promote tumorigenesis generally. We relate this specifically to SCCHN by focusing on several recent key studies specific to SCCHN, and by discussing the role TP53 mutation may play in this metabolic switch, given the fundamental role of this oncogenic event in SCCHN tumorigenesis. Finally, we also offer insight into the potential therapeutic implications this may have in the clinical setting and make recommendations for future study.

miR-133b, a particular member of myomiRs, coming into playing its unique pathological role in human cancer

MicroRNAs, a family of single-stranded and non-coding RNAs, play a crucial role in regulating gene expression at posttranscriptional level, by which it can mediate various types of physiological and pathological process in normal developmental progress and human disease, including cancer. The microRNA-133b originally defined as canonical muscle-specific microRNAs considering their function to the development and health of mammalian skeletal and cardiac muscles, but new findings coming from our group and others revealed that miR-133b have frequently abnormal expression in various kinds of human cancer and its complex complicated regulatory networks affects the tumorigenicity and development of malignant tumors. Very few existing reviews on miR-133b, until now, are principally about its role in homologous cluster (miR-1, −133 and -206s), however, most of constantly emerging new researches now are focused mainly on one of them, so In this article, to highlight the unique pathological role of miR-133b playing in tumor, we conduct a review to summarize the current understanding about one of the muscle-specific microRNAs, namely miR-133b, acting in human cancer. The review focused on the following four aspects: the overview of miR-133b, the target genes of miR-133b involved in human cancer, the expression of miR-133b and regulatory mechanisms leading to abnormal expression of miR-133b.

Targeting metabolic pathways for head and neck cancers therapeutics

Cancer cells have distinctive energy metabolism pathways that support their rapid cell division. The preference for anaerobic glycolysis under the normal oxygen condition is known as the Warburg effect and has been observed in head and neck cancers. These metabolic changes are controlled by cancer-related transcription factors, such as tumor suppressor gene and hypoxia inducible factor 1α. In addition, various metabolic enzymes also actively regulate cancer-specific metabolism including the switch between aerobic and anaerobic glycolysis. For a long time, these metabolic changes in cancer cells have been considered a consequence of transformation required to maintain the high rate of tumor cell replication. However, recent studies indicate that alteration of metabolism is sufficient to initiate tumor transformation. Indeed, oncogenic mutations in the metabolic enzymes, isocitrate dehydrogenase and succinate dehydrogenase, have been increasingly found in various cancers, including head and neck cancers. In the present review, we introduce recent findings regarding the cancer metabolism, including the molecular mechanisms of how they affect cancer pathogenesis and maintenance. We also discuss the current and future perspectives on therapeutics that target metabolic pathways, with an emphasis on head and neck cancer.

Posttranslational Modifications of Pyruvate Kinase M2: Tweaks that Benefit Cancer

Cancer cells rewire metabolism to meet biosynthetic and energetic demands. The characteristic increase in glycolysis, i.e., Warburg effect, now considered as a hallmark, supports cancer in various ways. To attain such metabolic reshuffle, cancer cells preferentially re-express the M2 isoform of pyruvate kinase (PKM2, M2-PK) and alter its quaternary structure to generate less-active PKM2 dimers. The relatively inactive dimers cause the accumulation of glycolytic intermediates that are redirected into anabolic pathways. In addition, dimeric PKM2 also benefits cancer cells through various non-glycolytic moonlight functions, such as gene transcription, protein kinase activity, and redox balance. A large body of data have shown that several distinct posttranslation modifications (PTMs) regulate PKM2 in a way that benefits cancer growth, e.g., formation of PKM2 dimers. This review discusses the recent advancements in our understanding of various PTMs and the benefits they impart to the sustenance of cancer. Understanding the PTMs in PKM2 is crucial to assess their therapeutic potential and to design novel anticancer strategies.

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.

MicroRNA-196a-5p is a potential prognostic marker of delayed lymph node metastasis in early-stage tongue squamous cell carcinoma

MicroRNAs (miRs) are expected to serve as prognostic tools for cancer. However, many miRs have been reported as prognostic markers of recurrence or metastasis in oral squamous cell carcinoma patients. We aimed to determine the prognostic markers in early-stage tongue squamous cell carcinoma (TSCC). Based on previous studies, we hypothesized that miR-10a, 10b, 196a-5p, 196a-3p, and 196b were prognostic markers and we retrospectively performed miR expression analyses using formalin-fixed paraffin-embedded sections of surgical specimens. Total RNA was isolated from cancer tissues and adjacent normal tissue as control, and samples were collected by laser-capture microdissection. After cDNA synthesis, reverse transcription-quantitative polymerase chain reaction was performed. Statistical analyses for patient clinicopathological characteristics, recurrence/metastasis, and survival rates were performed to discern their relationships with miR expression levels, and the 2^−ΔΔCq method was used. miR-196a-5p levels were significantly upregulated in early-stage TSCC, particularly in the lymph node metastasis (LNM) group. The LNM-free survival rate in the low miR-196a-5p ΔΔCq value regulation group was found to be lower than that in the high ΔΔCq value regulation group (P=0.0079). Receiver operating characteristic analysis of ΔΔCq values revealed that miR-196a-5p had a P-value=0.0025, area under the curve=0.740, and a cut-off value=−0.875 for distinguishing LNM. To our knowledge, this is the first study to examine LNM-related miRs in early-stage TSCC as well as miRs and ‘delayed LNM’ in head and neck cancer. miR-196a-5p upregulation may predict delayed LNM. Our data serve as a foundation for future studies to evaluate miR levels and facilitate the prediction of delayed LNM during early-stage TSCC, which prevent metastasis when combined with close follow-up and aggressive adjuvant therapy or elective neck dissection. Moreover, our data will serve as a foundation for future studies to evaluate whether miR-196a-5p can serve as a therapeutic marker for preventing metastasis.

miR-9 induces cell arrest and apoptosis of oral squamous cell carcinoma via CDK 4/6 pathway

Oral cancer remains a major public concern with considerable socioeconomic impact in the world, especially in southeast Asia. Despite substantial advancements have been made in treating oral cancer, the five-year survival rate for OSCC remained undesirable, and 35-55% patients developed recurrence within two years even with multimodality therapeutic strategies. Hence, identification of novel biomarkers for diagnosis and evaluating clinical outcome is of vital importance. MicroRNAs are 22-24 nt non-coding RNAs that could bind to 3' UTR of target mRNAs, thereby inducing degradation of mRNA or inhibiting translation. Due to its implication in regulation of post-transcriptional processes, the role of miRNAs in malignancies has been extensively studied, among which the discovery of functional miR-9 in oral squamous cell carcinoma (OSCC) remained to be elucidated. We first demonstrated that miR-9 was down-regulated in 21 OSCC patients, and we further found that forced expression of miR-9 could result in deterred cell proliferation and decreased ability to migrate and form colonies. Flow cytometry displayed cell-cycle arrested at G0/G1 phase. We next used Targetscan to predict target genes of miR-9. CDK6, a protein highly implicated in cell cycle control, was chosen for verification. Down-regulation of CDK6 and Cyclin D1 in Tca8113 transfected with miR-9 mimics indicate that the complex formed by both proteins may be the effector of the antiproliferative function of miR-9 in OSCCs. Considering small molecules are developed to target CDK4/6, our finding may provide valuable scientific evidence for research and development of therapies and diagnostic methodology in OSCCs.

MicroRNA regulation and analytical methods in cancer cell metabolism

The reprogramming of glucose metabolism from oxidative to glycolytic metabolism, known as the Warburg effect, is an anomalous characteristic of cancer cell metabolism. Recent studies have revealed a subset of microRNAs (miRNAs) that play critical roles in regulating the reprogramming of glucose metabolism in cancer cells. These miRNAs regulate cellular glucose metabolism by directly targeting multiple metabolic genes, including those encoding key glycolytic enzymes. In the first part of this review, we summarized the recent knowledge of miRNA regulation in the reprogramming of glucose metabolism in cancer cells and discussed the potential utilization of the key miRNA regulators as metabolic targets for developing new antitumor agents. Then, we summarized recent advances in methods and techniques for studying miRNA regulation in cancer cell metabolism.

MicroRNA Regulation of Glycolytic Metabolism in Glioblastoma

Glioblastoma (GBM) is the most aggressive and common malignant brain tumour in adults. A well-known hallmark of GMB and many other tumours is aerobic glycolysis. MicroRNAs (miRNAs) are a class of short nonprotein coding sequences that exert posttranscriptional controls on gene expression and represent critical regulators of aerobic glycolysis in GBM. In GBM, miRNAs regulate the expression of glycolytic genes directly and via the regulation of metabolism-associated tumour suppressors and oncogenic signalling pathways. This review aims to establish links between miRNAs expression levels, the expression of GBM glycolytic regulatory genes, and the malignant progression and prognosis of GBM. In this review, the involvement of 25 miRNAs in the regulation of glycolytic metabolism of GBM is discussed. Seven of these miRNAs have been shown to regulate glycolytic metabolism in other tumour types. Further eight miRNAs, which are differentially expressed in GBM, have also been reported to regulate glycolytic metabolism in other cancer types. Thus, these miRNAs could serve as potential glycolytic regulators in GBM but will require functional validation. As such, the characterisation of these molecular and metabolic signatures in GBM can facilitate a better understanding of the molecular pathogenesis of this disease.

Pyruvate kinase M2 deregulation enhances the metastatic potential of tongue squamous cell carcinoma

Pyruvate kinase M2 (PKM2) has been verified to correlate with the prognosis of many types of cancer. However, its role in the development and metastasis of tongue squamous cell carcinoma (TSCC) remains unclear. The immunohistochemistry (IHC) results confirmed that PKM2 is overexpressed in patients with TSCC. PKM2 up-regulation was related to lymph node metastasis and associated with reduced overall survival. According to the microarray analysis and Western blots, PKM2 expression was up-regulated in TSCC cells with enhanced metastatic potential. PKM2 knockdown inhibited cell migration and invasion, reduced SOD2 (manganese superoxide dismutase) activity and the intracellular H₂O₂ level, and inhibited tumour growth and lung metastasis in vivo. PKM2 overexpression promoted cell migration and invasion, and increased SOD2 activity and the intracellular H₂O₂ level. Moreover, miR-138 directly targeted PKM2 and inhibited PKM2 expression. Thus, PKM2 deregulation plays an important role in TSCC and may serve as a biomarker of metastatic potential or as a therapeutic target in patients with TSCC. PKM2, a miR-138 target gene, enhances the metastatic potential of TSCC through the SOD2-H₂O₂ pathway.

[MiR-133b Affect the Proliferation and Drug Sensitivity in A549 Lung Cancer Stem Cells by Targeting PKM2]

BACKGROUND

It has been proven that miR-133b could inhibit cancer cell growth, the expression level of miR-133b was significant reduction in lung cancer tissue and serum of patients, and increase the radiation sensitivity of squamous cell carcinoma by targeting PKM2, but the exist mechanisms is not clear. The aim of this study is to explore the effect of miR-133b on proliferation in A549 lung cancer stem cells and drug sensitivity in DDP, and to explore the relationship between miR-133b and PKM2 gene, as well as the effect of cancer stem cells.

METHODS

Using miRBase and miRNAMap database to sequence comparison miR-133b and PKM2 gene. Using immune magnetic separation method to select the CD133+/CD34+ lung cancer stem cells from A549 cells, and using flow cytometry to detect the purity. The expression of miR-133b mRNA was detected by real-time fluorescence quantitative PCR (qRT-PCR). Cell proliferation was detected by CCK8 assay. 15 μg/mL DDP was treated to cells which was transfected with miR-133b, and apoptosis was detected by flow Cytometry at 0 h, 12 h, 24 h, 72 h. The expression of PKM2 protein was detected by Western blot.

RESULTS

Gene binding site report that PKM2 gene may be the target gene of miR-133b; the results of flow cytometry showed that the purity of CD133+/CD34+ stem cells was (92.15±4.27)%. qRT-PCR results showed that compared with the control group, after overexpression of miR-133b, miR-133b was up-regulated and miR-133b was down regulated after miR-133b inhibition (P<0.05). Compared with the control group, cell proliferation of miR-133b mimics group was significantly decreased (P<0.05), PKM2 protein levels were significantly lower (P<0.05); and cell proliferation of the miR-133b inhibitor group and PKM2 level was increased (P<0.05). The apoptosis of miR-133b mimics group was significantly higher than that of control group (P<0.05) after DDP treatment with 12 h. The expression of PKM2 protein in miR-133b mimics+DDP group was significantly lower than that in control group (P<0.05).

CONCLUSIONS

Overexpression of miR-133b can inhibit the growth and proliferation of lung cancer stem cells by down regulating PKM2, and can enhance the sensitivity of lung cancer stem cells to DDP.

Impact of microRNA dynamics on cancer hallmarks: An oral cancer scenario

MicroRNAs are endogenous small noncoding RNAs that negatively regulate gene expression at posttranscriptional level. The discovery of microRNAs has identified a new layer of gene regulation mechanisms, which play a pivotal role in development as well as in various cellular processes, such as proliferation, differentiation, cell growth, and cell death. Deregulated microRNA expression favors acquisition of cancer hallmark traits as well as transforms the tumor microenvironment, leading to tumor development and progression. Many recent studies have revealed altered expression of microRNAs in oral carcinoma with several microRNAs shown to have key biological role in tumorigenesis functioning either as tumor suppressors or as tumor promoters. MicroRNA expression levels correlate with clinicopathological variables and have a diagnostic and prognostic value in oral carcinoma. For these reasons, microRNA has been a hot topic in oral cancer research for the last few years. In this review, we attempt to summarize the present understanding of microRNA deregulation in oral carcinoma, their role in acquiring cancer hallmarks, and their potential diagnostic and prognostic value for oral cancer management.

miR-373-3p Targets DKK1 to Promote EMT-Induced Metastasis via the Wnt/-Catenin Pathway in Tongue Squamous Cell Carcinoma

MicroRNAs (miRNAs) regulate gene expression and at the same time mediate tumorigenesis. miR-373-3p has diverse effects in tumors, but its role in tongue squamous cell carcinoma (TSCC) remains unknown. The purpose of this study is to determine the function of miR-373-3p in the progression of TSCC. Our results brought to light that miR-373-3p is markedly upregulated in clinical TSCC tissues compared with paired adjacent normal tissues and has significant correlation with a more aggressive TSCC phenotype in patients. Gain-of-function and loss-of-function studies revealed that ectopic miR-373-3p overexpression promoted the metastasis of TSCC cells. Notably, Wnt/β-catenin signaling was hyperactivated in TSCC cells overexpressing miR-373-3p, and this pathway was responsible for the epithelial-mesenchymal transition (EMT) induced by miR-373-3p. Furthermore, miR-373-3p directly targeted and suppressed Dickkopf-1 (DKK1), a negative regulator of the Wnt/β-catenin signaling cascade. These results demonstrate that, by directly targeting DKK1, miR-373-3p constitutively activated Wnt/β-catenin signaling, thus promoting the EMT-induced metastasis of TSCC. Taken together, our findings reveal a new regulatory mechanism for miR-373-3p and suggest that miR-373-3p might be a potential target in TSCC therapy.

Interplay between epigenetics and metabolism in oncogenesis: mechanisms and therapeutic approaches

Epigenetic and metabolic alterations in cancer cells are highly intertwined. Oncogene-driven metabolic rewiring modifies the epigenetic landscape via modulating the activities of DNA and histone modification enzymes at the metabolite level. Conversely, epigenetic mechanisms regulate the expression of metabolic genes, thereby altering the metabolome. Epigenetic-metabolomic interplay has a critical role in tumourigenesis by coordinately sustaining cell proliferation, metastasis and pluripotency. Understanding the link between epigenetics and metabolism could unravel novel molecular targets, whose intervention may lead to improvements in cancer treatment. In this review, we summarized the recent discoveries linking epigenetics and metabolism and their underlying roles in tumorigenesis; and highlighted the promising molecular targets, with an update on the development of small molecule or biologic inhibitors against these abnormalities in cancer.

Epigenetics in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most common type of oral neoplasm, accounting for over 90% of all oral malignancies and 38% of head and neck tumors. Worldwide, OSCC is the eighth most common human cancer, with more than 500,000 new cases being diagnosed every year with a fairly onerous prognosis, encouraging further research on factors that might modify disease outcome. Genetic and/or environmental risk factors associated with the development of oral cancer have been sufficiently understood (smoking, alcohol, betel, diet, living habits, etc.). Knowledge of the genetic basis in oral carcinogenesis is still a challenging task. To improve the diagnosis and prevention, a previously unknown type of chromatin modification, known as epigenetic, which is defined as heritable DNA changes that are not encoded in the sequence itself and which are reversible and increasingly appear to serve fundamental roles in cell differentiation and development are studied. Tumors shed their DNA into the blood and epigenetic changes that occur early during tumorigenesis, sometimes even in premalignant lesions, can provide valuable biomarkers. Key components involved in epigenetic regulation are DNA methylation, histone modifications and modifications in micro ribonucleic acids (miRNAs). Epigenetic modifications may contribute to aberrant epigenetic mechanisms seen in oral precancers and cancers. In the near future, epigenetic variations found in oral dysplastic cells can act as a molecular fingerprint for malignancies.

Reprogramming of glucose metabolism in hepatocellular carcinoma: Progress and prospects

Hepatocellular carcinoma (HCC) is one of the most lethal cancers, and its rate of incidence is rising annually. Despite the progress in diagnosis and treatment, the overall prognoses of HCC patients remain dismal due to the difficulties in early diagnosis and the high level of tumor invasion, metastasis and recurrence. It is urgent to explore the underlying mechanism of HCC carcinogenesis and progression to find out the specific biomarkers for HCC early diagnosis and the promising target for HCC chemotherapy. Recently, the reprogramming of cancer metabolism has been identified as a hallmark of cancer. The shift from the oxidative phosphorylation metabolic pathway to the glycolysis pathway in HCC meets the demands of rapid cell proliferation and offers a favorable microenvironment for tumor progression. Such metabolic reprogramming could be considered as a critical link between the different HCC genotypes and phenotypes. The regulation of metabolic reprogramming in cancer is complex and may occur via genetic mutations and epigenetic modulations including oncogenes, tumor suppressor genes, signaling pathways, noncoding RNAs, and glycolytic enzymes etc. Understanding the regulatory mechanisms of glycolysis in HCC may enrich our knowledge of hepatocellular carcinogenesis and provide important foundations in the search for novel diagnostic biomarkers and promising therapeutic targets for HCC.