TRIM21 and PHLDA3 negatively regulate the crosstalk between the PI3K/AKT pathway and PPP metabolism

Characterizing the role of Phlda3 in the development of acute toxicity and malignant transformation of hematopoietic cells induced by total-body irradiation in mice

The tumor suppressor p53 is a transcriptional factor that plays a crucial role in controlling acute toxicity and long-term malignant transformation of hematopoietic cells induced by genotoxic stress such as ionizing radiation. Among all transcriptional targets of p53, one gene that is robustly induced by radiation is the pleckstrin homology domain-only protein Phlda3. However, the role that Phlda3 plays in regulating the response of hematopoietic cells to radiation is unknown. Here, using isogenic cell lines and genetically engineered mouse models, we showed that radiation induces Phlda3 in human leukemia cells and mouse normal hematopoietic cells in a p53-dependent manner. However, deletion of the Phlda3 gene did not ameliorate radiation-induced acute hematologic toxicity. In addition, distinct from mice that lose p53, loss of Phlda3 did not alter the latency and incidence of radiation-induced thymic lymphoma in mice. Remarkably, whole-exome sequencing data showed that lymphomas in irradiated Phlda3+/+ mice harbor a significantly higher number of single nucleotide variants (SNVs) and indels compared to lymphomas in irradiated Phlda3+/- and Phlda3-/- littermates. Together, our results indicate that although deletion of Phlda3 does not accelerate the development of radiation-induced thymic lymphoma, fewer SNVs and indels are necessary to initiate lymphomagenesis after radiation exposure when Phlda3 is silenced.

Hypoxia-induced reprogramming of glucose-dependent metabolic pathways maintains the stemness of human bone marrow-derived endothelial progenitor cells

The benefits of hypoxia for maintaining the stemness of cultured human bone marrow-derived endothelial progenitor cells (BM EPCs) have previously been demonstrated but the mechanisms responsible remain unclear. Growing evidences suggest that cellular metabolism plays an important role in regulating stem cell fate and self-renewal. Here we aimed to detect the changes of glucose metabolism and to explore its role on maintaining the stemness of BM EPCs under hypoxia. We identified the metabolic status of BM EPCs by using extracellular flux analysis, LC-MS/MS, and ¹³C tracing HPLC-QE-MS, and found that hypoxia induced glucose metabolic reprogramming, which manifested as increased glycolysis and pentose phosphate pathway (PPP), decreased tricarboxylic acid (TCA) and mitochondrial respiration. We further pharmacologically altered the metabolic status of cells by employing various of inhibitors of key enzymes of glycolysis, PPP, TCA cycle and mitochondria electron transport chain (ETC). We found that inhibiting glycolysis or PPP impaired cell proliferation either under normoxia or hypoxia. On the contrary, inhibiting pyruvate oxidation, TCA or ETC promoted cell proliferation under normoxia mimicking hypoxic conditions. Moreover, promoting pyruvate oxidation reverses the maintenance effect of hypoxia on cell stemness. Taken together, our data suggest that hypoxia induced glucose metabolic reprogramming maintains the stemness of BM EPCs, and artificial manipulation of cell metabolism can be an effective way for regulating the stemness of BM EPCs, thereby improving the efficiency of cell expansion in vitro.

The p52-ZER6/G6PD axis alters aerobic glycolysis and promotes tumor progression by activating the pentose phosphate pathway

Abnormal glucose metabolism is a highlight of tumor metabolic reprogramming and is closely related to the development of malignancies. p52-ZER6, a C₂H₂-type zinc finger protein, promotes cell proliferation and tumorigenesis. However, its role in the regulation of biological and pathological functions remains poorly understood. Here, we examined the role of p52-ZER6 in tumor cell metabolic reprogramming. Specifically, we demonstrated that p52-ZER6 promotes tumor glucose metabolic reprogramming by positively regulating the transcription of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme in the pentose phosphate pathway (PPP). By activating the PPP, p52-ZER6 was found to enhance the production of nucleotides and nicotinamide adenine dinucleotide phosphate, thereby providing tumor cells with the building blocks of ribonucleic acids and cellular reductants for reactive oxygen species scavenging, which subsequently promotes tumor cell proliferation and viability. Importantly, p52-ZER6 promoted PPP-mediated tumorigenesis in a p53-independent manner. Taken together, these findings reveal a novel role for p52-ZER6 in regulating G6PD transcription via a p53-independent process, ultimately resulting in tumor cell metabolic reprogramming and tumorigenesis. Our results suggest that p52-ZER6 is a potential target for the diagnosis and treatment of tumors and metabolic disorders.

PHLDA3 activated by BARX2 transcription, suppresses the malignant development of esophageal squamous cell carcinoma by downregulating PI3K/AKT levels

BACKGROUND

Low pleckstrin homology-like domain family A, member 3 (PHLDA3) expression has been reported to be associated with cancer specificity and disease-free survival in esophageal squamous cell carcinoma (ESCC), and was an independent predictor of postoperative recurrence. However, the specific mechanisms involved are still unclear. This paper aimed to explore the role and its mechanisms of PHLDA3 in ESCC.

MATERIALS AND METHODS

PHLDA3 and BarH-like homeobox 2 (BARX2) expressions in ESCC were predicted by Gene Expression Profiling Interactive Analysis (GEPIA) analysis and determined by quantitative real-time polymerase chain reaction (qRT-PCR) and western Blot. Western blot detected the expression of proteins associated with migration, angiogenesis and phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB/AKT) signaling pathway. The University of California Santa Cruz Genomics Institute (UCSC) database predicted that the relationship of BARX2 and PHLDA3 promoter and JASPAR identified the possible binding sites. Dual luciferase gene reporter verified PHLDA3 promoter activity, and the relationship of both was determined by chromatin immunoprecipitation (CHIP). Cell counting kit (CCK)-8, 5-ethynyl-2'-deoxyuridine (EDU) and colony formation were used to assess cell proliferation. Wound healing and transwell were used to detect cell migration and invasion ability. Tube formation assay was applied to assess angiogenesis. Mice were injected with transfected KYSE30 cells under the right axilla. Body weight and tumor volume and mass were recorded for each group of mice. Immunohistochemistry was performed to detect KI67 level in tumor tissues.

RESULTS

Both PHLDA3 and BARX2 were downregulated in ESCC. The upregulated PHLDA3 suppressed PI3K/AKT expression. In addition, BARX2 bound to the PHLDA3 promoter and transcriptionally activated PHLDA3. PHLDA3 overexpression inhibited ESCC cell proliferation, migration, invasion and angiogenesis, but this effect was reversed by BARX2 knockdown. In addition, BARX2 overexpression inhibited ESCC cell proliferation, migration, invasion and angiogenesis, but this effect was reversed by PHLDA3 knockdown.

CONCLUSION

PHLDA3 was transcriptionally activated by BARX2 and inhibited malignant progression of ESCC by downregulating PI3K/AKT levels.

LncRNA XR_595552 inhibition alleviates intermittent hypoxia-induced cardiomyocyte damage via activating the PI3K/AKT pathway

BACKGROUND

Although the long noncoding RNAs (lncRNAs) expression profiles have been observed in previous study, the biological functions and underlying mechanisms of lncRNAs in OSA-related cardiac injury have not been elucidated. In the present study, we investigated a novel lncRNA, lncRNA XR_595552, and evaluated its role in intermittent hypoxia (IH)-induced damage in H9c2 cardiomyocytes.

METHODS

H9c2 cells were exposed to IH condition. Real-time quantitative polymerase chain reaction (RT-qPCR) was conducted to measure the expression changes of lncRNA XR_595552 in H9c2 cells stimulated by IH. H9c2 cells were subjected to IH after transfection. CCK-8 was used to evaluate cell viability, and apoptosis was analyzed by Western blotting. Additionally, the regulatory relationship between lncRNA XR_595552 and PI3K/AKT was tested by RT-qPCR and Western blot.

RESULTS

IH significantly induced injury in H9c2 cells (inhibited cell viability and promoted cell apoptosis). lncRNA XR_595552 was upregulated in a cell model of IH. Inhibition of lncRNA XR_595552 protected H9c2 cells against IH-induced damage, as the viability was increased, Bax, Caspase-9, and Caspase-3 were downregulated, and Bcl-2 was upregulated. More interestingly, lncRNA XR_595552 downregulation activated the PI3K/AKT pathway. Blocking the PI3K/AKT signal pathway by the use of LY294002 eliminated the myocardioprotective effects of lncRNA XR_595552 in H9c2 cells under IH condition.

CONCLUSIONS

The results show that lncRNA XR_595552, a novel lncRNA, may play a protective role in attenuating IH-induced injury in cardiomyocytes via a regulating PI3K/AKT pathway. The findings suggest that this lncRNA could serve as a therapeutic target to treat OSA-related cardiovascular disorders.

The Role of PI3K/AKT/mTOR Signaling in Hepatocellular Carcinoma Metabolism

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths in the world. Metabolic reprogramming is considered a new hallmark of cancer, but it remains unclearly described in HCC. The dysregulation of the PI3K/AKT/mTOR signaling pathway is common in HCC and is, therefore, a topic of further research and the concern of developing a novel target for liver cancer therapy. In this review, we illustrate mechanisms by which this signaling network is accountable for regulating HCC cellular metabolism, including glucose metabolism, lipid metabolism, amino acid metabolism, pyrimidine metabolism, and oxidative metabolism, and summarize the ongoing clinical trials based on the inhibition of the PI3K/AKT/mTOR pathway in HCC.

Metabolic reprogramming of immune cells in pancreatic cancer progression

Abnormal intracellular metabolism not only provides nutrition for tumor occurrence and development, but also sensitizes the function of various immune cells in the immune microenvironment to promote tumor immune escape. This review discusses the emerging role of immune cells in the progress of pancreatic cancer, acrossing metabolic reprogramming and key metabolic pathways present in different immune cell types. At present, the hotspots of metabolic reprogramming of immune cells in pancreatic cancer progression mainly focuses on glucose metabolism, lipid metabolism, tricarboxylic acid cycle and amino acid metabolism, which affect the function of anti-tumor immune cells and immunosuppressive cells in the microenvironment, such as macrophages, dendritic cells, T cells, myeloid-derived suppressor cells, neutrophils and B cells by a series of key metabolic signaling pathways, such as PI3K/AKT, mTOR, AMPK, HIF-1α, c-Myc and p53. Drugs that target the tumor metabolism pathways for clinical treatment of pancreatic cancer are also systematically elaborated, which may constitute food for others' projects involved in clinical anti-cancer research.

PI3K/AKT/mTOR pathway, hypoxia, and glucose metabolism: Potential targets to overcome radioresistance in small cell lung cancer

Small cell lung cancer (SCLC) is a highly aggressive tumor type for which limited therapeutic progress has been made. Platinum-based chemotherapy with or without thoracic radiotherapy remains the backbone of treatment, but most patients with SCLC acquire therapeutic resistance. Given the need for more effective therapies, better elucidation of the molecular pathogenesis of SCLC is imperative. The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is frequently activated in SCLC and strongly associated with resistance to ionizing radiation in many solid tumors. This pathway is an important regulator of cancer cell glucose metabolism, and its activation probably effects radioresistance by influencing bioenergetic processes in SCLC. Glucose metabolism has three main branches-aerobic glycolysis, oxidative phosphorylation, and the pentose phosphate pathway-involved in radioresistance. The interaction between the PI3K/AKT/mTOR pathway and glucose metabolism is largely mediated by hypoxia-inducible factor 1 (HIF-1) signaling. The PI3K/AKT/mTOR pathway also influences glucose metabolism through other mechanisms to participate in radioresistance, including inhibiting the ubiquitination of rate-limiting enzymes of the pentose phosphate pathway. This review summarizes our understanding of links among the PI3K/AKT/mTOR pathway, hypoxia, and glucose metabolism in SCLC radioresistance and highlights promising research directions to promote cancer cell death and improve the clinical outcome of patients with this devastating disease.

TRIM21 aggravates cardiac injury after myocardial infarction by promoting M1 macrophage polarization

Macrophage polarization followed by myocardial infarction (MI) is essential for wound healing. Tripartite motif-containing protein 21 (TRIM21), a member of E3 ubiquitin ligases, is emerging as a mediator in cardiac injury and heart failure. However, its function in modulating post-MI macrophage polarization remains elusive. Here, we detected that the levels of TRIM21 significantly increased in macrophages of wild-type (WT) mice after MI. In contrast, MI was ameliorated in TRIM21 knockout (TRIM21-/-) mice with improved cardiac remodeling, characterized by a marked decrease in mortality, decreased infarct size, and improved cardiac function compared with WT-MI mice. Notably, TRIM21 deficiency impeded the post-MI apoptosis and DNA damage in the hearts of mice. Consistently, the accumulation of M1 phenotype macrophages in the infarcted tissues was significantly reduced with TRIM21 deletion. Mechanistically, the deletion of TRIM21 orchestrated the process of M1 macrophage polarization at least partly via a PI3K/Akt signaling pathway. Overall, we identify TRIM21 drives the inflammatory response and cardiac remodeling by stimulating M1 macrophage polarization through a PI3K/Akt signaling pathway post-MI.

TRIM family contribute to tumorigenesis, cancer development, and drug resistance

The tripartite-motif (TRIM) family represents one of the largest classes of putative single protein RING-finger E3 ubiquitin ligases. TRIM family is involved in a variety of cellular signaling transductions and biological processes. TRIM family also contributes to cancer initiation, progress, and therapy resistance, exhibiting oncogenic and tumor-suppressive functions in different human cancer types. Moreover, TRIM family members have great potential to serve as biomarkers for cancer diagnosis and prognosis. In this review, we focus on the specific mechanisms of the participation of TRIM family members in tumorigenesis, and cancer development including interacting with dysregulated signaling pathways such as JAK/STAT, PI3K/AKT, TGF-β, NF-κB, Wnt/β-catenin, and p53 hub. In addition, many studies have demonstrated that the TRIM family are related to tumor resistance; modulate the epithelial–mesenchymal transition (EMT) process, and guarantee the acquisition of cancer stem cells (CSCs) phenotype. In the end, we havediscussed the potential of TRIM family members for cancer therapeutic targets.

The complexity of p53-mediated metabolic regulation in tumor suppression

Although the classic activities of p53 including induction of cell-cycle arrest, senescence, and apoptosis are well accepted as critical barriers to cancer development, accumulating evidence suggests that loss of these classic activities is not sufficient to abrogate the tumor suppression activity of p53. Numerous studies suggest that metabolic regulation contributes to tumor suppression, but the mechanisms by which it does so are not completely understood. Cancer cells rewire cellular metabolism to meet the energetic and substrate demands of tumor development. It is well established that p53 suppresses glycolysis and promotes mitochondrial oxidative phosphorylation through a number of downstream targets against the Warburg effect. The role of p53-mediated metabolic regulation in tumor suppression is complexed by its function to promote both cell survival and cell death under different physiological settings. Indeed, p53 can regulate both pro-oxidant and antioxidant target genes for complete opposite effects. In this review, we will summarize the roles of p53 in the regulation of glucose, lipid, amino acid, nucleotide, iron metabolism, and ROS production. We will highlight the mechanisms underlying p53-mediated ferroptosis, AKT/mTOR signaling as well as autophagy and discuss the complexity of p53-metabolic regulation in tumor development.

N6-methyladenosine modification of circ_0003215 suppresses the pentose phosphate pathway and malignancy of colorectal cancer through the miR-663b/DLG4/G6PD axis

Circular RNAs (circRNAs) are a recently discovered kind of regulatory RNAs that have emerged as critical biomarkers of various types of cancers. Metabolic reprogramming has gradually been identified as a distinct hallmark of cancer cells. The pentose phosphate pathway (PPP) plays an indispensable role in satisfying the bioenergetic and biosynthetic demands of cancer cells. However, little is known about the role of circRNAs and PPP in colorectal cancer (CRC). The novel circ_0003215 was identified at low levels in CRC and was negatively correlated with larger tumor size, higher TNM stage, and lymph node metastasis. The decreased level of circ_0003215 was resulted from the RNA degradation by m6A writer protein YTHDF2. A series of functional assays demonstrated that circ_0003215 inhibited cell proliferation, migration, invasion, and CRC tumor metastasis in vivo and in vitro. Moreover, circ_0003215 regulated the expression of DLG4 via sponging miR-663b, thereby inducing the metabolic reprogramming in CRC. Mechanismly, DLG4 inhibited the PPP through the K48-linked ubiquitination of glucose-6-phosphate dehydrogenase (G6PD). Taken together, we have identified m6A-modified circ_0003215 as a novel regulator of metabolic glucose reprogramming that inhibited the PPP and the malignant phenotype of CRC via the miR-663b/DLG4/G6PD axis.

The emerging roles of TRIM21 in coordinating cancer metabolism, immunity and cancer treatment

Tripartite motif containing-21 (TRIM21), an E3 ubiquitin ligase, was initially found to be involved in antiviral responses and autoimmune diseases. Recently studies have reported that TRIM21 plays a dual role in cancer promoting and suppressing in the occurrence and development of various cancers. Despite the fact that TRIM21 has effects on multiple metabolic processes, inflammatory responses and the efficacy of tumor therapy, there has been no systematic review of these topics. Herein, we discuss the emerging role and function of TRIM21 in cancer metabolism, immunity, especially the immune response to inflammation associated with tumorigenesis, and also the cancer treatment, hoping to shine a light on the great potential of targeting TRIM21 as a therapeutic target.

Fumarate suppresses B-cell activation and function through direct inactivation of LYN

Activated B cells increase central carbon metabolism to fulfill their bioenergetic demands, yet the mechanistic basis for this, as well as metabolic regulation in B cells, remains largely unknown. Here, we demonstrate that B-cell activation reprograms the tricarboxylic acid cycle and boosts the expression of fumarate hydratase (FH), leading to decreased cellular fumarate abundance. Fumarate accumulation by FH inhibition or dimethyl-fumarate treatment suppresses B-cell activation, proliferation and antibody production. Mechanistically, fumarate is a covalent inhibitor of tyrosine kinase LYN, a key component of the BCR signaling pathway. Fumarate can directly succinate LYN at C381 and abrogate LYN activity, resulting in a block to B-cell activation and function in vitro and in vivo. Therefore, our findings uncover a previously unappreciated metabolic regulation of B cells, and reveal LYN is a natural sensor of fumarate, connecting cellular metabolism to B-cell antigen receptor signaling.

Curcumin Inhibits Hyperandrogen-Induced IRE1α-XBP1 Pathway Activation by Activating the PI3K/AKT Signaling in Ovarian Granulosa Cells of PCOS Model Rats

Background

Hyperandrogenism is a common characteristic of polycystic ovary syndrome (PCOS). Long-term, continuous exposure to hyperandrogenic environments may cause excessive endoplasmic reticulum (ER) stress in ovarian granulosa cells (GCs). Curcumin is a polyphenol extracted from turmeric rhizomes which has several pharmacological effects that may benefit patients with PCOS. To explore whether curcumin can inhibit hyperandrogen-induced ER stress in ovarian GCs of PCOS rats and to elucidate the possible underlying mechanisms.

Methods

We developed PCOS model rats by exposure to hyperandrogenic conditions and divided the rats into control, PCOS, and PCOS+curcumin (200 mg/kg, for 8 weeks) groups. The levels of ER stress-related proteins and PI3K/AKT phosphorylation were measured in the ovarian tissue of all experimental groups by real-time quantitative PCR, western blotting, immunohistochemistry, and immunofluorescence. Subsequent in vitro analysis on primary cultured GCs was performed to confirm the influence of curcumin on ER stress inhibition by immunofluorescence and western blotting.

Results

Curcumin protects GCs from hyperandrogen-induced apoptosis in PCOS model rats by inhibiting the ER stress-related IRE1α-XBP1 pathway and activating the PI3K/AKT signaling pathway.

Conclusions

These observations indicate that curcumin might be a safe and useful supplement for PCOS patients.

Identification and Validation of TRIM25 as a Glucose Metabolism Regulator in Prostate Cancer

Prostate cancer (PCa) malignant progression is accompanied with the reprogramming of glucose metabolism. However, the genes involved in the regulation of glucose metabolism in PCa are not fully understood. Here, we propose a new method, DMRG, which constructs a weighted differential network (W-K-DN) to define the important metabolism-related genes. Based on biological knowledge and prostate cancer transcriptome data, a tripartite motif-containing 25 (TRIM25) was defined using DMRG; TRIM25 was involved in the regulation of glucose metabolism, which was verified by overexpressing or knocking down TRIM25 in PCa cell lines. Differential expression analysis of TCA cycle enzymes revealed that TRIM25 regulated isocitrate dehydrogenase 1 (IDH1) and fumarate hydratase (FH) expression. Moreover, a protein–RNA interaction network of TRIM25 revealed that TRIM25 interacted with RNA-binding proteins, including DExH-box helicase 9 and DEAD-box helicase 5, to play a role in regulating the RNA processing of metabolic enzymes, including IDH1 and FH. Furthermore, TRIM25 expression level was found to be positively correlated with Gleason scores in PCa patient tissues. In conclusion, this study provides a new method to define genes influencing tumor progression, and sheds light on the role of the defined TRIM25 in regulating glucose metabolism and promoting PCa malignancy.

FAT10 Combined with Miltefosine Inhibits Mitochondrial Apoptosis and Energy Metabolism in Hypoxia-Induced H9C2 Cells by Regulating the PI3K/AKT Signaling Pathway

Hypoxia-induced cardiomyocyte apoptosis is the main contributor to heart diseases. Human leukocyte antigen F-associated transcript 10 (FAT10), the small ubiquitin-like protein family subtype involved in apoptosis, is expressed in the heart and exhibits cardioprotective functions. This study explored the impact of FAT10 on hypoxia-induced cardiomyocyte apoptosis and the involved mechanisms. The cardiomyocyte cell line H9C2 was cultivated in hypoxia-inducing conditions (94% N₂, 5% CO_2, and 1% O₂) and the expression of FAT10 in hypoxia-stimulated H9C2 cells was identified. For this, FAT10 overexpression/interference vectors were exposed to transfection into H9C2 cells with/without the PI3K/AKT inhibitor, miltefosine. The results indicated that hypoxia exposure decreased the FAT10 expression, suppressed H9C2 cell growth, disrupted mitochondrial metabolism, and promoted H9C2 cell apoptosis and oxidative stress. However, these impacts were reversed by the FAT10 overexpression. In addition, the inhibition of PI3K/AKT in FAT10-overexpressing cells suppressed cell proliferation, impaired mitochondrial metabolism, and promoted apoptosis and oxidative stress response. The findings demonstrated that FAT10 inhibited mitochondrial apoptosis and energy metabolism in hypoxia-stimulated H9C2 cells through the PI3K/AKT pathway. This finding can be utilized for developing therapeutic targets for treating heart disorders associated with hypoxia-induced apoptosis.

Molecular Regulation of Yak Preadipocyte Differentiation and Proliferation by LncFAM200B and ceRNA Regulatory Network Analysis

The positive regulatory role of lncFAM200B in differentiation and lipid deposition in yak intramuscular preadipocytes has been demonstrated in our previous study. However, the regulatory mechanisms remain unclear. In this study, we aimed to produce complete mRNA and microRNA (miRNA) profiles after adenovirus-mediated lncFAM200B overexpression in yak preadipocytes using high-throughput sequencing. We constructed a competing endogenous RNA (ceRNA) network with lncFAM200B as the core and identified the functions of the selected target miRNA during cell proliferation and differentiation. We obtained 118 differentially expressed genes (DEGs) after lncFAM200B overexpression, 76 of which were up-regulated, including Notch signaling members NOTCH3, DTX3L, and HES4, and 42 DEGs were down-regulated, including genes related to the cell cycle (CCNA2, BUB1, CDC20, TOP2A, and KIF20A). Additionally, many ubiquitin-mediated proteolysis pathway members were also significantly up-regulated (BUA7, PML, TRIM21, and TRIM25). MiRNA sequencing showed that 13 miRNAs were significantly up-regulated, and 12 miRNAs were down-regulated. Among them, 29 targets of 10 differentially expressed miRNAs (DEMs) were differentially expressed, including miR-152-FBXO33, miR-6529a-TRIM21, miR-148c-NOTCH3, and the miR-6529b-HES4 axis. We further verified that overexpression and inhibition of miR-6529a can inhibit and promote, respectively, the proliferation and differentiation of preadipocytes. Taken together, our study not only revealed the regulatory network of lncFAM200B during yak preadipocytes differentiation but also laid a foundation for elucidating the cause for lower intramuscular fat content in yaks at the molecular level.

Aspirin sensitivity of PIK3CA-mutated Colorectal Cancer: potential mechanisms revisited

PIK3CA mutations are amongst the most prevalent somatic mutations in cancer and are associated with resistance to first-line treatment along with low survival rates in a variety of malignancies. There is evidence that patients carrying PIK3CA mutations may benefit from treatment with acetylsalicylic acid, commonly known as aspirin, particularly in the setting of colorectal cancer. In this regard, it has been clarified that Class IA Phosphatidylinositol 3-kinases (PI3K), whose catalytic subunit p110α is encoded by the PIK3CA gene, are involved in signal transduction that regulates cell cycle, cell growth, and metabolism and, if disturbed, induces carcinogenic effects. Although PI3K is associated with pro-inflammatory cyclooxygenase-2 (COX-2) expression and signaling, and COX-2 is among the best-studied targets of aspirin, the mechanisms behind this clinically relevant phenomenon are still unclear. Indeed, there is further evidence that the protective, anti-carcinogenic effect of aspirin in this setting may be mediated in a COX-independent manner. However, until now the understanding of aspirin's prostaglandin-independent mode of action is poor. This review will provide an overview of the current literature on this topic and aims to analyze possible mechanisms and targets behind the aspirin sensitivity of PIK3CA-mutated cancers.

P3H4 Promotes Malignant Progression of Lung Adenocarcinoma via Interaction with EGFR

Simple Summary

Lung adenocarcinoma (LUAD) is the most common histologic subtype of lung cancer. Studies have shown that P3H4 is a key gene underlying the malignant progression of LUAD. A potential biomarker and therapeutic target, P3H4 is involved in various cancers, but its molecular mechanism in LUAD remains unclear. Based on a series of experiments, we found that it significantly promoted the metastasis and proliferation of LUAD in vivo and in vitro.

Abstract

Lung cancer is associated with the greatest number of cancer-related deaths worldwide. Lung adenocarcinoma (LUAD) accounts for 85% of all cases of lung cancer. Despite recent advances in treatment, the 5-year survival rate remains less than 15%. Thus, the diagnostic and therapeutic role of LUAD remain to be further studied. The prolyl 3-hydroxylase family member 4 (P3H4) is involved in various cancers, but little is known about its role in LUAD. Our study demonstrated that the P3H4 gene was upregulated in LUAD. Clinically, the expression of P3H4 was positively correlated with an advanced TNM stage and shorter survival. Functionally, P3H4 plays a significant role in the metastasis and proliferation of LUAD both in vitro and in vivo. Mechanistically, P3H4 might interact with EGFR to regulate the metabolic substances. Our study indicated that P3H4 is a critical gene in the malignant progression of LUAD and represents a potential biomarker and therapeutic target.

Construction of a competing endogenous RNA network to analyse glucose-6-phosphate dehydrogenase dysregulation in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common malignant tumour with high rates of morbidity and mortality worldwide. Therefore, it is of great significance to find new molecular markers for HCC diagnosis and treatment. G6PD is known to be dysregulated in a variety of tumours. In addition, the ceRNA network plays a crucial role in the occurrence and development of HCC. However, the mechanism by which the ceRNA network regulates G6PD in HCC remains unclear. We used TCGA-LIHC data to analyse the possibility of using G6PD as an independent prognostic marker. Univariate Cox proportional hazards regression, multivariate Cox proportional hazards regression, and receiver operating characteristic curve analysis were used to analyse the influence of G6PD overexpression on the prognosis of HCC patients. We also analysed the biological function of G6PD, its effect on the immune microenvironment, and drug sensitivity. Finally, we constructed a ceRNA network of lncRNAs/miR-122-5p/G6PD to explore the regulatory mechanism of G6PD. G6PD was highly expressed in HCC, was related to pathological stage and poor prognosis, and could be used as an independent prognostic indicator of HCC. The expression of G6PD was closely related to the immune microenvironment of HCC. In addition, the expression of G6PD in HCC could be regulated by the ceRNA network. Therefore, G6PD can be used as an immunotherapy target to improve the survival and prognosis of HCC patients, and the ceRNA regulatory network of G6PD has potential diagnostic and therapeutic value for HCC.

Preparation of a miR-155-activating nucleic acid nanoflower to study the molecular mechanism of miR-155 in inflammation

At present, the molecular mechanisms underlying inflammation remain unclear. In recent years, research on inflammation has focused on stimulating cell inflammation by using exogenous pro-inflammatory substances such as lipopolysaccharide (LPS) or inflammatory factors. To investigate the molecular mechanism of inflammation from a new perspective, we designed a nucleic acid nanoflowers (NFs) complex to directly activate inflammatory genes to study the inflammatory response without the need for external microbial factors to trigger an inflammatory response. An RNAa-type target gene-activated NFs was designed. Human umbilical vein endothelial cells (HUVECs) were transfected with NFs carrying small activating RNA (saRNAs) to directly co-activate microRNA (miR)-155 and SHIP1 genes. After RNA activation (RNAa)-type NFs were transferred into HUVECs, the expression of miR-155 and pro-inflammatory and cancer-related factors increased, anti-inflammatory factors were reduced, cell proliferation increased, and cell migration was promoted. IL-1β protein levels were decreased and SHIP1 expression was downregulated. When miR-155 and its target SHIP1 were both activated, the expression of both was unaltered, maintaining cell homeostasis. This points towards miR-155 overexpression can trigger inflammation, and that miR-155 and its target genes act as a molecular switch role in the development of inflammation.

Impacts of Oxidative Stress and PI3K/AKT/mTOR on Metabolism and the Future Direction of Investigating Fucoidan-Modulated Metabolism

The critical factors for regulating cancer metabolism are oxidative stress and phosphoinositide-3-kinase/AKT serine-threonine kinase/mechanistic target of the rapamycin kinase (PI3K/AKT/mTOR). However, the metabolic impacts of oxidative stress and PI3K/AKT/mTOR on individual mechanisms such as glycolysis (Warburg effect), pentose phosphate pathway (PPP), fatty acid synthesis, tricarboxylic acid cycle (TCA) cycle, glutaminolysis, and oxidative phosphorylation (OXPHOS) are complicated. Therefore, this review summarizes the individual and interacting functions of oxidative stress and PI3K/AKT/mTOR on metabolism. Moreover, natural products providing oxidative stress and PI3K/AKT/mTOR modulating effects have anticancer potential. Using the example of brown algae-derived fucoidan, the roles of oxidative stress and PI3K/AKT/mTOR were summarized, although their potential functions within diverse metabolisms were rarely investigated. We propose a potential application that fucoidan may regulate oxidative stress and PI3K/AKT/mTOR signaling to modulate their associated metabolic regulations. This review sheds light on understanding the impacts of oxidative stress and PI3K/AKT/mTOR on metabolism and the future direction of metabolism-based cancer therapy of fucoidan.

Pleckstrin homology-like domain family A, member 3, a miR-19a-3p-regulated gene, suppresses tumor growth in osteosarcoma by downregulating the Akt pathway

Pleckstrin homology-like domain family A, member 3 (PHLDA3), is emerging as a critical regulator for multiple cancers. Nevertheless, the expression and role of PHLDA3 in osteosarcoma remain unknown. Herein, we purposed to elucidate the role of PHLDA3 in the progression and chemoresistance of osteosarcoma. According to the bioinformatics analysis, PHLDA3 expression was low in osteosarcoma patients, and low content was linked to poor prognosis. Additionally, activation of PHLDA3 suppressed osteosarcoma cell proliferation, migration, and chemoresistance, whereas PHLDA3 inhibition caused the opposite effects. Mechanistically, our data revealed that PHLDA3 negatively regulates the Akt/GSK3β signaling cascade in osteosarcoma. Furthermore, we found that miR-19a-3p might exert its oncogenic function by inhibiting PHLDA3 expression in osteosarcoma. These results demonstrated miR-19a-3p/ PHLDA3/ Akt/GSK3β axis has a pivotal role in osteosarcoma, and PHLDA3 is a prospective therapeutic target for treating osteosarcoma.

Estrogen receptor-α36 is involved in diallyl sulfide-induced inhibition of malignant growth of HepG2 and Huh7 hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is a highly malignant disease that currently lacks effective treatment. Epidemiological studies have suggested the preventive role of raw garlic intake in different tumors, such as HCC. Although diallyl sulfide (DAS), the main component of garlic extracts, has been reported to inhibit the growth of HCC cells, the underlying mechanism remains elusive. This study aimed to investigate the inhibitory effect of DAS on the growth of HepG2 and Huh7 hepatocellular carcinoma cells and its underlying mechanism. HepG2 and Huh7 cells were treated with DAS and nude mice were intrahepatically injected with human HCC HepG2 cells and maintained with or without DAS administration for 28 days. MTS and clonogenic assays revealed that DAS inhibited the growth and clonogenicity of HepG2 and Huh7 hepatocellular carcinoma cells. Furthermore, DAS inhibited the growth of xenograft tumors accompanied by a decreased rate of pathological karyomitosis as observed by H&E staining. The expression levels of estrogen receptor-α36 (ER-α36) and epidermal growth factor receptor (EGFR) in HepG2 and Huh7 cells and in xenograft tumors derived from HepG2 cells after DAS treatment were detected by immunohistochemistry and western blotting. We found that DAS disrupted the positive regulatory loop between ER-α36 and EGFR, and decreased the phosphorylation of AKT at Ser 473 both in vivo and in vitro. DAS also induced cell apoptosis, as evidenced by Hoechst and TUNEL staining. Western blotting revealed activation of caspase3, increased BAX and decreased Bcl-2 expression. However, the ER-α36 expression knockdown attenuated DAS-induced ERK and AKT phosphorylation in HCC cells. DAS was also able to inhibit ER-α36-mediated activation of the MAPK/ERK signaling induced by estrogen. Thus, our results indicate that ER-α36 signaling is involved in DAS-induced inhibition of HCC cell growth both in vitro and in vivo.

Overcoming resistance to immune checkpoint therapy in PTEN-null prostate cancer by intermittent anti-PI3Kα/β/δ treatment

Combining immune checkpoint therapy (ICT) and targeted therapy holds great promises for broad and long-lasting anti-cancer therapies. However, combining ICT with anti-PI3K inhibitors have been challenging because the multifaceted effects of PI3K on both cancer cells and immune cells within the tumor microenvironment. Here we find that intermittent but not daily dosing of a PI3Kα/β/δ inhibitor, BAY1082439, on Pten-null prostate cancer models could overcome ICT resistance and unleash CD8⁺ T cell-dependent anti-tumor immunity in vivo. Mechanistically, BAY1082439 converts cancer cell-intrinsic immune-suppression to immune-stimulation by promoting IFNα/IFNγ pathway activation, β2-microglubin expression and CXCL10/CCL5 secretion. With its preferential regulatory T cell inhibition activity, BAY1082439 promotes clonal expansion of tumor-associated CD8⁺ T cells, most likely via tertiary lymphoid structures. Once primed, tumors remain T cell-inflamed, become responsive to anti-PD-1 therapy and have durable therapeutic effect. Our data suggest that intermittent PI3K inhibition can alleviate Pten-null cancer cell-intrinsic immunosuppressive activity and turn "cold" tumors into T cell-inflamed ones, paving the way for successful ICT.

Chromatin remodeling induced by ARID1A loss in lung cancer promotes glycolysis and confers JQ1 vulnerability

ARID1A is a key mammalian SWI/SNF complex subunit that is mutated in 5%-11% of lung cancers. Although recent studies have elucidated the mechanism underlying dysregulation of SWI/SNF complexes in cancers, the significance of ARID1A loss and its implications in lung cancers remain poorly defined. This study investigates how ARID1A loss affects initiation and progression of lung cancer. In genetically engineered mouse models bearing mutant Kras and a deficient Trp53 allele (KP), ARID1A loss (KPA) promoted lung tumorigenesis. Analysis of the transcriptome profiles of KP and KPA tumors suggested enhanced glycolysis following ARID1A loss, and expression of the glycolytic regulators Pgam1, Pkm, and Pgk1 was significantly increased in ARID1A-deficient lung tumors. Furthermore, ARID1A loss increased chromatin accessibility and enhanced HIF1α binding to the promoter regions of Pgam1, Pkm, and Pgk1. Loss of ARID1A in lung adenocarcinoma also resulted in loss of histone deacetylase 1 (HDAC1) recruitment, increasing acetylation of histone 4 lysine at the promoters of Pgam1, Pkm, and Pgk1 and subsequently enhancing BRD4-driven transcription of these genes. Metabolic analyses confirmed that glycolysis is enhanced in ARID1A-deficient tumors, and genetic or pharmacologic inhibition of glycolysis inhibited lung tumorigenesis in KPA mice. Treatment with the small molecule bromodomain and extra terminal protein (BET) inhibitor JQ1 compromised both initiation and progression of ARID1A-deficient lung adenocarcinoma. ARID1A negatively correlated with glycolysis-related genes in human lung adenocarcinoma. Overall, ARID1A loss leads to metabolic reprogramming that supports tumorigenesis but also confers a therapeutic vulnerability that could be harnessed to improve the treatment of ARID1A-deficient lung cancer.

Identification of the alpha linolenic acid metabolism-related signature associated with prognosis and the immune microenvironment in nasopharyngeal carcinoma

BACKGROUND

Tumor metabolism is important for cancer progression. Nevertheless, the role of the metabolism pathway and related molecules in nasopharyngeal carcinoma (NPC) is limited.

METHODS

Open-accessed data was downloaded from The Cancer Genome Atlas database. All the analysis was performed using the R software and the package in R environments.

RESULTS

In our study, we firstly explored the role of 21 metabolism-related pathways in NPC patients. We found that the steroid biosynthesis and biosynthesis of unsaturated fatty acids were risk factors, while the alpha linolenic acid metabolism was a protective factor. Then, the alpha linolenic acid metabolism aroused our interest. A total of 128 differentially expressed genes (DEGs) were identified, including 71 downregulated and 57 upregulated genes identified between high and low alpha linolenic acid metabolism level. Based on these DEGs, we constructed a prognosis model including DEFB4B, FOXL2NB, MDGA2, RTL1, SLURP2, TMEM151B and TSPAN19, which showed great prediction efficiency in both training and validation cohorts. Clinical correlation analysis showed that high-risk patients might have worse clinical pathology parameters. Pathway enrichment analysis showed that riskscore was positively correlated with angiogenesis, DNA repair, G2/M checkpoints, IL6/JAK/STAT3 signaling, KRAS signaling up, WNT beta-catenin signaling, PI3K/AKT/mTOR signaling, yet positively correlated with inflammatory response, xenobiotic metabolism, TNF-α signaling via NFKB and interferon-gamma response. Immune infiltration analysis showed that the riskscore was positively correlated with the M2 and M0 macrophages, but negatively correlated with neutrophils, plasma cells, follicular helper T cells and resting dendritic cells Moreover, we found that the low-risk patients might be more sensitive to immunotherapy and lapatinib.

CONCLUSIONS

In all, our study identified the genes associated with alpha linolenic acid metabolism and constructed an effective prognosis model which could robustly predict NPC patients prognosis.

The RNA-Binding Protein Musashi1 Regulates a Network of Cell Cycle Genes in Group 4 Medulloblastoma

Medulloblastoma is the most common malignant brain tumor in children. Treatment with surgery, irradiation, and chemotherapy has improved survival in recent years, but patients are frequently left with devastating neurocognitive and other sequelae. Patients in molecular subgroups 3 and 4 still experience a high mortality rate. To identify new pathways contributing to medulloblastoma development and create new routes for therapy, we have been studying oncogenic RNA-binding proteins. We defined Musashi1 (Msi1) as one of the main drivers of medulloblastoma development. The high expression of Msi1 is prevalent in Group 4 and correlates with poor prognosis while its knockdown disrupted cancer-relevant phenotypes. Genomic analyses (RNA-seq and RIP-seq) indicated that cell cycle and division are the main biological categories regulated by Msi1 in Group 4 medulloblastoma. The most prominent Msi1 targets include CDK2, CDK6, CCND1, CDKN2A, and CCNA1. The inhibition of Msi1 with luteolin affected the growth of CHLA-01 and CHLA-01R Group 4 medulloblastoma cells and a synergistic effect was observed when luteolin and the mitosis inhibitor, vincristine, were combined. These findings indicate that a combined therapeutic strategy (Msi1 + cell cycle/division inhibitors) could work as an alternative to treat Group 4 medulloblastoma.

Identification and validation of PGLS as a metabolic target for early screening and prognostic monitoring of gastric cancer

BACKGROUND

Gastric cancer is the third leading cause of cancer-related death in the world. The purpose of the present study is to investigate the expression and prognostic significance of 6-phosphogluconolactonase (PGLS) in gastric cancer.

METHODS

The protein extracted from a panel of four pairs of gastric cancer tissues and adjacent tissues, labeled with iTRAQ (8-plex) reagents, and followed by LC-ESI-MS/MS. The expressions of proteins were further validated by immunohistochemistry analysis. The expression levels of mRNA were analyzed and validated in the Oncomine database. The correlations of PGLS with prognostic outcomes were evaluated with Kaplan-Meier plotter database.

RESULTS

The present study found that PGLS was significantly up-regulated in gastric cancer by using iTRAQ-based proteomics and immunohistochemistry analysis. The sensitivity of PGLS in gastric cancer was 72.9%. The high expression of PGLS was significantly correlated with TNM staging in gastric cancer (p = 0.02). The overexpression of PGLS predicts worse overall survival (OS) and post-progression survival (PPS) for gastric cancer (OS, HR = 1.48, p = 2.1e-05; PPS, HR = 1.35, p = 0.015). Specifically, the high PGLS expression predicts poor OS, PPS in male gastric cancer patients, in patients with lymph node metastasis and in patients with Her-2 (-).

CONCLUSIONS

These findings suggested that PGLS was aberrantly expressed in gastric cancer and predicts poor overall survival, post-progression survival for gastric cancer patients. The present study collectively supported that PGLS is an important target for early determining and follow-up monitoring for gastric cancer.

NeuroD1 promotes tumor cell proliferation and tumorigenesis by directly activating the pentose phosphate pathway in colorectal carcinoma

Tumor metabolic reprogramming ensures that cancerous cells obtain sufficient building blocks, energy, and antioxidants to sustain rapid growth and for coping with oxidative stress. Neurogenic differentiation factor 1 (NeuroD1) is upregulated in various types of tumors; however, its involvement in tumor cell metabolic reprogramming remains unclear. In this study, we report that NeuroD1 is positively correlated with glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme in the pentose phosphate pathway (PPP), in colorectal cancer cells. In addition, the regulation of G6PD by NeuroD1 alters tumor cell metabolism by stimulating the PPP, leading to enhanced production of nucleotides and NADPH. These, in turn, promote DNA and lipid biosynthesis in tumor cells, while decreasing intracellular levels of reactive oxygen species. Mechanistically, we showed that NeuroD1 binds directly to the G6PD promoter to activate G6PD transcription. Consequently, tumor cell proliferation and colony formation are enhanced, leading to increased tumorigenic potential in vitro and in vivo. These findings reveal a novel function of NeuroD1 as a regulator of G6PD, whereby its oncogenic activity is linked to tumor cell metabolic reprogramming and regulation of the PPP. Furthermore, NeuroD1 represents a potential target for metabolism-based anti-tumor therapeutic strategies.

Involvement of the circular RNA/microRNA/glucose-6-phosphate dehydrogenase axis in the pathological mechanism of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related death worldwide with high mortality. The incidence of HCC is increasing in China. Abnormal activation of glucose-6-phosphate dehydrogenase (G6PD) exists in all malignant tumors, including HCC, and is closely related to the development of HCC. In addition, the differential expression of non-coding RNAs is closely related to the development of HCC. This systematic review focuses on the relationship between G6PD, HCC, and non-coding RNA, which form the basis for the circRNA/miRNA/G6PD axis in HCC. The circular RNA (circRNA)/microRNA (miRNA)/G6PD axis is involved in development of HCC. We proposed that non-coding RNA molecules of the circRNA/miRNA/G6PD axis may be novel biomarkers for the pathological diagnosis, prognosis, and targeted therapy of HCC.

6-Phosphogluconolactonase Promotes Hepatocellular Carcinogenesis by Activating Pentose Phosphate Pathway

Hepatocellular carcinoma (HCC) has a poor prognosis due to the rapid disease progression and early metastasis. The metabolism program determines the proliferation and metastasis of HCC; however, the metabolic approach to treat HCC remains uncovered. Here, by analyzing the liver cell single-cell sequencing data from HCC patients and healthy individuals, we found that 6-phosphogluconolactonase (PGLS), a cytosolic enzyme in the oxidative phase of the pentose phosphate pathway (PPP), expressing cells are associated with undifferentiated HCC subtypes. The Cancer Genome Atlas database showed that high PGLS expression was correlated with the poor prognosis in HCC patients. Knockdown or pharmaceutical inhibition of PGLS impaired the proliferation, migration, and invasion capacities of HCC cell lines, Hep3b and Huh7. Mechanistically, PGLS inhibition repressed the PPP, resulting in increased reactive oxygen species level that decreased proliferation and metastasis and increased apoptosis in HCC cells. Overall, our study showed that PGLS is a potential therapeutic target for HCC treatment through impacting the metabolic program in HCC cells.

PHLDA3 inhibition protects against myocardial ischemia/reperfusion injury by alleviating oxidative stress and inflammatory response via the Akt/Nrf2 axis

Pleckstrin homology-like domain family A, member 3 (PHLDA3) has a particularly critical role in regulating cell survival under stress conditions. However, whether PHLDA3 plays a role in myocardial ischemia/reperfusion injury has not been studied. We aimed to assess the possible role of PHLDA3 in myocardial ischemia/reperfusion (I/R) injury. PHLDA3 expression was increased in myocardial tissue from rats with myocardial I/R injury and rat cardiomyocytes with hypoxia/reoxygenation (H/R) injury. PHLDA3 knockdown protected against myocardial I/R injury in vivo and H/R injury in vitro. Inhibition of PHLDA3 increased the activation of nuclear factor erythroid-derived 2-related factor 2 (Nrf2) associated with regulation of the Akt/glycogen synthase kinase-3β (GSK-3β) axis. Repression of Nrf2 reversed PHLDA3-inhibition-mediated cardioprotective effects. Taken together, our work demonstrates that PHLDA3 inhibition exerts a protective role in myocardial I/R injury via regulation of the Akt/GSK-3β/Nrf2 axis. We suggest PHLDA3 as an attractive target for developing treatments against myocardial I/R injury.

Cancer cell metabolic plasticity in migration and metastasis

Metabolic reprogramming is a hallmark of cancer metastasis in which cancer cells manipulate their metabolic profile to meet the dynamic energetic requirements of the tumor microenvironment. Though cancer cell proliferation and migration through the extracellular matrix are key steps of cancer progression, they are not necessarily fueled by the same metabolites and energy production pathways. The two main metabolic pathways cancer cells use to derive energy from glucose, glycolysis and oxidative phosphorylation, are preferentially and plastically utilized by cancer cells depending on both their intrinsic metabolic properties and their surrounding environment. Mechanical factors in the microenvironment, such as collagen density, pore size, and alignment, and biochemical factors, such as oxygen and glucose availability, have been shown to influence both cell migration and glucose metabolism. As cancer cells have been identified as preferentially utilizing glycolysis or oxidative phosphorylation based on heterogeneous intrinsic or extrinsic factors, the relationship between cancer cell metabolism and metastatic potential is of recent interest. Here, we review current in vitro and in vivo findings in the context of cancer cell metabolism during migration and metastasis and extrapolate potential clinical applications of this work that could aid in diagnosing and tracking cancer progression in vivo by monitoring metabolism. We also review current progress in the development of a variety of metabolically targeted anti-metastatic drugs, both in clinical trials and approved for distribution, and highlight potential routes for incorporating our recent understanding of metabolic plasticity into therapeutic directions. By further understanding cancer cell energy production pathways and metabolic plasticity, more effective and successful clinical imaging and therapeutics can be developed to diagnose, target, and inhibit metastasis.

Biochanin A Inhibits Glioblastoma Growth via Restricting Glycolysis and Mitochondrial Oxidative Phosphorylation

Abnormal metabolism serves a critical role in glioblastoma (GBM). Biochanin A (BCA), a flavonoid phenolic compound found in edible and herbal plants, has antioxidative and antitumor activities. However, it remains unclear whether BCA has an effect on energy metabolism. The aim of the present study was to evaluate the anticancer effects and molecular mechanism of the effect of BCA on energy metabolism. We observed that BCA inhibited the growth of U251 cells by the mitochondria-mediated intrinsic apoptotic pathway. BCA treatment reduced metabolic function, repressed mitochondrial membrane potential, and increased the production of reactive oxygen species (ROS) in GBM. In addition, we found that BCA decreased aerobic glycolysis by inactivation of the AKT/mTOR pathway. Taken together, the results demonstrate that treatment with BCA inhibited the proliferation of GBM by regulating metabolic reprogramming.

MTOR Signaling and Metabolism in Early T Cell Development

The mechanistic target of rapamycin (mTOR) controls cell fate and responses via its functions in regulating metabolism. Its role in controlling immunity was unraveled by early studies on the immunosuppressive properties of rapamycin. Recent studies have provided insights on how metabolic reprogramming and mTOR signaling impact peripheral T cell activation and fate. The contribution of mTOR and metabolism during early T-cell development in the thymus is also emerging and is the subject of this review. Two major T lineages with distinct immune functions and peripheral homing organs diverge during early thymic development; the αβ- and γδ-T cells, which are defined by their respective TCR subunits. Thymic T-regulatory cells, which have immunosuppressive functions, also develop in the thymus from positively selected αβ-T cells. Here, we review recent findings on how the two mTOR protein complexes, mTORC1 and mTORC2, and the signaling molecules involved in the mTOR pathway are involved in thymocyte differentiation. We discuss emerging views on how metabolic remodeling impacts early T cell development and how this can be mediated via mTOR signaling.

Curcumin Regulates Cancer Progression: Focus on ncRNAs and Molecular Signaling Pathways

Curcumin [(1E,6E) ‑1,7‑bis(4‑hydroxy‑3‑methoxyphenyl) hepta‑1,6‑diene‑3,5‑ dione] is a natural polyphenol derived from the rhizome of the turmeric plant Curcuma longa. Accumulated evidences have presented curcumin’s function in terms of anti-inflammatory, antioxidant properties, and especially anti-tumor activities. Studies demonstrated that curcumin could exert anti-tumor activity via multiple biological signaling pathways, such as PI3K/Akt, JAK/STAT, MAPK, Wnt/β-catenin, p53, NF-ĸB and apoptosis related signaling pathways. Moreover, Curcumin can inhibit tumor proliferation, angiogenesis, epithelial-mesenchymal transition (EMT), invasion and metastasis by regulating tumor related non-coding RNA (ncRNA) expression. In this review, we summarized the roles of curcumin in regulating signaling pathways and ncRNAs in different kinds of cancers. We also discussed the regulatory effect of curcumin through inhibiting carcinogenic miRNA and up regulating tumor suppressive miRNA. Furthermore, we aim to illustrate the cross regulatory relationship between ncRNA and signaling pathways, further to get a better understanding of the anti-tumor mechanism of curcumin, thus lay a theoretical foundation for the clinical application of curcumin in the future.

Regulation and metabolic functions of mTORC1 and mTORC2

Cells metabolize nutrients for biosynthetic and bioenergetic needs to fuel growth and proliferation. The uptake of nutrients from the environment and their intracellular metabolism is a highly controlled process that involves cross talk between growth signaling and metabolic pathways. Despite constant fluctuations in nutrient availability and environmental signals, normal cells restore metabolic homeostasis to maintain cellular functions and prevent disease. A central signaling molecule that integrates growth with metabolism is the mechanistic target of rapamycin (mTOR). mTOR is a protein kinase that responds to levels of nutrients and growth signals. mTOR forms two protein complexes, mTORC1, which is sensitive to rapamycin, and mTORC2, which is not directly inhibited by this drug. Rapamycin has facilitated the discovery of the various functions of mTORC1 in metabolism. Genetic models that disrupt either mTORC1 or mTORC2 have expanded our knowledge of their cellular, tissue, as well as systemic functions in metabolism. Nevertheless, our knowledge of the regulation and functions of mTORC2, particularly in metabolism, has lagged behind. Since mTOR is an important target for cancer, aging, and other metabolism-related pathologies, understanding the distinct and overlapping regulation and functions of the two mTOR complexes is vital for the development of more effective therapeutic strategies. This review discusses the key discoveries and recent findings on the regulation and metabolic functions of the mTOR complexes. We highlight findings from cancer models but also discuss other examples of the mTOR-mediated metabolic reprogramming occurring in stem and immune cells, type 2 diabetes/obesity, neurodegenerative disorders, and aging.

The Role of the Pentose Phosphate Pathway in Diabetes and Cancer

The pentose phosphate pathway (PPP) branches from glucose 6-phosphate (G6P), produces NADPH and ribose 5-phosphate (R5P), and shunts carbons back to the glycolytic or gluconeogenic pathway. The PPP has been demonstrated to be a major regulator for cellular reduction-oxidation (redox) homeostasis and biosynthesis. Enzymes in the PPP are reported to play important roles in many human diseases. In this review, we will discuss the role of the PPP in type 2 diabetes and cancer.