Elevated glucose-6-phosphate dehydrogenase expression in the cervical cancer cases is associated with the cancerigenic event of high-risk human papillomaviruses

G6PD is a prognostic biomarker correlated with immune infiltrates in lung adenocarcinoma and pulmonary arterial hypertension

BACKGROUND

Lung adenocarcinoma (LUAD) with Pulmonary arterial hypertension (PAH) shows a poor prognosis. Detecting related genes is imperative for prognosis prediction.

METHODS

The gene expression profiles of LUAD and PAH were acquired from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) database, respectively. The co-expression modules associated with LUAD and PAH were evaluated using the Weighted Gene Co-Expression Network Analysis (WGCNA). The relationship between key gene expression with immune-cell infiltration and the tumor immune microenvironment (TIME) was evaluated. We confirmed the mRNA and protein levels in vivo and vitro. G6PD knockdown was used to conduct the colony formation assay, transwell invasion assay, and scratch wound assay of A549 cells. EDU staining and CCK8 assay were performed on G6PD knockdown HPASMCs. We identified therapeutic drug molecules and performed molecular docking between the key gene and small drug molecules.

RESULTS

Three major modules and 52 overlapped genes were recognized in LUAD and PAH. We identified the key gene G6PD, which was significantly upregulated in LUAD and PAH. In addition, we discovered a significant difference in infiltration for most immune cells between high- and low-G6PD expression groups. The mRNA and protein expressions of G6PD were significantly upregulated in LUAD and PAH. G6PD knockdown decreased proliferation, cloning, and migration of A549 cells and cell proliferation in HPASMCs. We screened five potential drug molecules against G6PD and targeted glutaraldehyde by molecular docking.

CONCLUSIONS

This study reveals that G6PD is an immune-related biomarker and a possible therapeutic target for LUAD and PAH patients.

Smilax china root extract as a novel Glucose- 6-phosphate dehydrogenase inhibitor for the treatment of hepatocellular carcinoma

A novel therapeutic strategy for cancer treatment is to target altered tumor metabolism. Glucose- 6-phosphate dehydrogenase (G6PD) has been recently discovered to be implicated in apoptosis and angiogenesis, making it an excellent target in cancer treatment. The current study aimed to screen the plant extracts library to find potent hits against G6PD through enzymatic assay. Protein expression was induced by IPTG and purified using Ni-NTA columns after transformation of the pET-24a-HmG6PD plasmid into E. coli BL21-DE3 strain. An enzymatic assay was established by using purified rG6PD protein, for the screening of G6PD inhibitors. Out of 46 plant extracts screened, the sixteen plant extracts have shown inhibitory activity against the G6PD enzyme. At doses from 1 to 4 µg/ml, this extract demonstrated concentration-dependent inhibition of G6PD with an IC₅₀ value of I.397 µg/ml. Moreover, the anticancer activity evaluation against HepG2 cells determined Smilax china as a potent inhibitor of cancer cells (IC₅₀ value of 16.017 μg/ml). The acute and subacute toxicities were not observed in mice with various concentrations (50, 100, 200 and 2000 mg/kg). Furthermore, to identify the compounds from Smilax china as G6PD inhibitors, a literature-based phytochemical investigation of Smilax china was conducted, and sixty compounds were docked against the NADP+ and G6P binding sites of G6PD. The results of this study showed that three compounds were Scirpusin A, Smilachinin and Daucosterol with MolDock Score of −156.832, −148.215, and −145.733 respectively, against NADP+ binding site of G6PD. Conclusively, Smilax china root extract could be a safer drug candidate for the treatment of hepatocellular carcinoma.

The Possible Role of Glucose-6-Phosphate Dehydrogenase in the SARS-CoV-2 Infection

Glucose-6-phosphate dehydrogenase (G6PD) is the second rate-limiting enzyme of the pentose phosphate pathway. This enzyme is present in the cytoplasm of all mammalian cells, and its activity is essential for an adequate functioning of the antioxidant system and for the response of innate immunity. It is responsible for the production of nicotinamide adenine dinucleotide phosphate (NADPH), the first redox equivalent, in the pentose phosphate pathway. Viral infections such as SARS-CoV-2 may induce the Warburg effect with an increase in anaerobic glycolysis and production of lactate. This condition ensures the success of viral replication and production of the virion. Therefore, the activity of G6PD may be increased in COVID-19 patients raising the level of the NADPH, which is needed for the enzymatic and non-enzymatic antioxidant systems that counteract the oxidative stress caused by the cytokine storm. G6PD deficiency affects approximately 350–400 million people worldwide; therefore, it is one of the most prevalent diseases related to enzymatic deficiency worldwide. In G6PD-deficient patients exposed to SARS-CoV-2, the amount of NADPH is reduced, increasing the susceptibility for viral infection. There is loss of the redox homeostasis in them, resulting in severe pneumonia and fatal outcomes.

HPV16 E6 Promotes the Progression of HPV Infection-Associated Cervical Cancer by Upregulating Glucose-6-Phosphate Dehydrogenase Expression

Cervical cancer, which is significantly associated with high-risk human papillomavirus (HPV) infection, currently ranks the fourth most common cancer among women worldwide. Previous literature reported that the elevated expression of G6PD was significantly correlated with the occurrence and deterioration of human cervical cancer, especially with the cervical cancer with HPV16 and HPV18 infection. In this study, we verified that G6PD expression has a strong positive correlation with HPV16 E6 levels in cervical cancer tissues and cells. In addition, regulating the expression of HPV16 E6 significantly affected the proliferation, apoptosis, migration, and invasion in the cervical cancer HeLa cells, as well as the transcript and protein levels of G6PD. The luciferase reporter assay and ChIP assay proved that HPV16 E6 stimulated the transcription of G6PD mRNA and subsequently enhanced the expression of G6PD through directly binding to the specific sites in the promoter of G6PD. Our findings reveal that HPV16 E6 is a novel regulatory factor of G6PD. Furthermore, by regulating the expression of G6PD, HPV16 E6 might promote the proliferation and migration potential, and inhibit apoptosis of cervical cancer cells, which ultimately contributed to the progression and metastasis of cervical cancer.

The Microenvironment Is a Critical Regulator of Muscle Stem Cell Activation and Proliferation

Skeletal muscle has a remarkable capacity to regenerate following injury, a property conferred by a resident population of muscle stem cells (MuSCs). In response to injury, MuSCs must double their cellular content to divide, a process requiring significant new biomass in the form of nucleotides, phospholipids, and amino acids. This new biomass is derived from a series of intracellular metabolic cycles and alternative routing of carbon. In this review, we examine the link between metabolism and skeletal muscle regeneration with particular emphasis on the role of the cellular microenvironment in supporting the production of new biomass and MuSC proliferation.

The Redox Role of G6PD in Cell Growth, Cell Death, and Cancer

The generation of reducing equivalent NADPH via glucose-6-phosphate dehydrogenase (G6PD) is critical for the maintenance of redox homeostasis and reductive biosynthesis in cells. NADPH also plays key roles in cellular processes mediated by redox signaling. Insufficient G6PD activity predisposes cells to growth retardation and demise. Severely lacking G6PD impairs embryonic development and delays organismal growth. Altered G6PD activity is associated with pathophysiology, such as autophagy, insulin resistance, infection, inflammation, as well as diabetes and hypertension. Aberrant activation of G6PD leads to enhanced cell proliferation and adaptation in many types of cancers. The present review aims to update the existing knowledge concerning G6PD and emphasizes how G6PD modulates redox signaling and affects cell survival and demise, particularly in diseases such as cancer. Exploiting G6PD as a potential drug target against cancer is also discussed.

miR‑378a‑3p inhibits cellular proliferation and migration in glioblastoma multiforme by targeting tetraspanin 17

Glioblastoma multiforme (GBM) is the most common and aggressive brain tumor and patients with this disease tend to have poor clinical outcome. MicroRNAs (miRs) are important regulators of a number of key pathways implicated in tumor pathogenesis. Recently, the expression of miR‑378 was shown to be dysregulated in several different types of cancer, including gastric cancer, colorectal cancer and oral carcinoma. Additional studies have demonstrated that miR‑378 may serve as a potential therapeutic target against human breast cancer. However, the underlying mechanisms and potential targets of miR‑378a‑3p involved in GBM remain unknown. The aim of the present of was to determine the effects of miR‑378a‑3p and its potential targets. Tetraspanin 17 (TSPAN17) is involved in the neoplastic events in GBM and is a member of the tetraspanin family of proteins. The tetraspanins are involved in the regulation of cell growth, migration and invasion of several different types of cancer cell lines, and may potentially act as an oncogene associated with GBM pathology. The results of the present study showed that high miR‑378a‑3p and low TSPAN17 expression levels were associated with improved survival in patients with GBM. Additionally, high levels of TSPAN17 were linked to the poor prognosis of patients with GBM aged 50‑60, larger tumor sizes (≥5 cm) and an advanced World Health Organization stage. TSPAN17 was identified and confirmed as a direct target of miR‑378a‑3p using a luciferase reporter assay in human glioma cell lines. Overexpression of miR‑378a‑3p in either of U87MG or MT‑330 cells decreased the expression of TSPAN17, promoted apoptosis and decreased proliferation, migration and invasion. Overexpression of TSPAN17 attenuated the aforementioned effects induced by miR‑378a‑3p overexpression. The present study indicated that miR‑378a‑3p suppresses the progression of GBM by reducing TSPAN17 expression, and may thus serve as a potential therapeutic target for treating patients with GBM.

Neuroprotection induced by Navβ2‑knockdown in APP/PS1 transgenic neurons is associated with NEP regulation

Voltage‑gated sodium channel β2 (Navβ2), as an unconventional substrate of β‑site amyloid precursor protein cleaving enzyme 1, is involved in regulating the neuronal surface expression of sodium channels. A previous study demonstrated that knockdown of Navβ2 protected neurons and induced spatial cognition improvement by partially reducing pathological amyloidogenic processing of amyloid precursor protein (APP) in aged APP/presenilin 1 (PS1) transgenic mice. The present study aimed to investigate whether Navβ2 knockdown altered APP metabolism via regulation of the Aβ‑degrading enzyme neprilysin (NEP). APPswe/PS1ΔE9 mice (APP/PS1 transgenic mice with a C57BL/6J genetic background) carrying a Navβ2‑knockdown mutation (APP/PS1/Navβ2‑kd) or without Navβ2 knockdown (APP/PS1) were used for cell culture and further analysis. The present results demonstrated that in APP/PS1 mouse‑derived neurons, Navβ2 knockdown partially reversed the reduction in pathological APP cleavage, and the recovery of neurite extension and neuron area. Additionally, Navβ2 knockdown increased NEP activity and levels, and the levels of intracellular domain fragment binding to the NEP promoter. The present findings suggested that knockdown of Navβ2 reversed the APP/PS1 mutation‑induced deficiency in amyloid β degradation by regulating NEP.

Electro-acupuncture-induced neuroprotection is associated with activation of the IGF-1/PI3K/Akt pathway following adjacent dorsal root ganglionectomies in rats

The aim of the present study was to investigate the putative role and underlying mechanisms of insulin-like growth factor 1 (IGF-1) in mediating neuroplasticity in rats subjected to partial dorsal root ganglionectomies following electro-acupuncture (EA) treatment. The rats underwent bilateral removal of the L1-L4 and L6 dorsal root ganglia (DRG), sparing the L5 DRG, and were subsequently subjected to 28 days of EA treatment at two paired acupoints, zusanli (ST 36)-xuanzhong (GB 39) and futu (ST 32)-sanyinjiao (SP 6), as the EA Model group. Rats that received partial dorsal root ganglionectomies without EA treatment served as a control (Model group). Subsequently, herpes simplex virus (HSV)-IGF-1, HSV-small interfering (si) RNA-IGF-1 and the associated control vectors were injected into the L5 DRG of rats in the EA Model group. HSV-IGF-1 transfection enhanced EA-induced neuroplasticity, which manifested as partial recovery in locomotor function, remission hyperpathia, growth of DRG-derived spared fibers, increased expression of phosphorylated (p-) phosphatidylinositol 3-kinase (PI3K) and Akt, and increased pPI3K/PI3K and pAkt/Akt expression ratios. By contrast, HSV-siRNA-IGF-1 treatment attenuated these effects induced by HSV-IGF-1 transfection. The results additionally demonstrated that HSV-IGF-1 transfection augmented the outgrowth of neurites in cultured DRG neurons, and interference of the expression of IGF-1 retarded neurite outgrowth. Co-treatment with a PI3K inhibitor or Akt siRNA inhibited the aforementioned effects induced by the overexpression of IGF-1. In conclusion, the results of the present study demonstrated the crucial roles of IGF-1 in EA-induced neuroplasticity following adjacent dorsal root ganglionectomies in rats via the PI3K/Akt signaling pathway.

MicroRNA-206 suppresses proliferation and predicts poor prognosis of HR-HPV-positive cervical cancer cells by targeting G6PD

Cervical cancer (CC) is one of the most frequent gynecological malignancies in females worldwide. Aberrant expression of microRNA (miR)-206 was reported to play an important role in tumor progression. The aim of the present study was to evaluate the potential role of miR-206 and verify its influence on the function of glucose-6-phosphate dehydrogenase (G6PD) in CC. Western blot analysis and RT-PCR were employed to measure miR-206 and G6PD expression. Luciferase assays were performed to validate G6PD as miR-206 targets. CCK-8 assay was performed to examine the regulation of miR-206 and G6PD on CC proliferation. The result showed that miR-206 was downregulated, while G6PD was upregulated in high risk human papillomavirus (HR-HPV)(+) CC. miR-206 directly targeted the 3'-UTR of G6PD. miR-206 overexpressed or G6PD low-expressed suppressed cell proliferation. miR-206 low expressed or G6PD overexpressed predicted poor prognosis. In conclusion, miR-206 reduced cancer growth and suppresses the G6PD expression in CC. This newly identified miR-206 may provide further insight into tumor progression and offers a promising target for the CC therapy.

Proteomic Investigation to Identify Anticancer Targets of Nemopilema nomurai Jellyfish Venom in Human Hepatocarcinoma HepG2 Cells

Nemopilema nomurai is a giant jellyfish that blooms in East Asian seas. Recently, N. nomurai venom (NnV) was characterized from a toxicological and pharmacological point of view. A mild dose of NnV inhibits the growth of various kinds of cancer cells, mainly hepatic cancer cells. The present study aims to identify the potential therapeutic targets and mechanism of NnV in the growth inhibition of cancer cells. Human hepatocellular carcinoma (HepG2) cells were treated with NnV, and its proteome was analyzed using two-dimensional gel electrophoresis, followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI/TOF/MS). The quantity of twenty four proteins in NnV-treated HepG2 cells varied compared to non-treated control cells. Among them, the amounts of fourteen proteins decreased and ten proteins showed elevated levels. We also found that the amounts of several cancer biomarkers and oncoproteins, which usually increase in various types of cancer cells, decreased after NnV treatment. The representative proteins included proliferating cell nuclear antigen (PCNA), glucose-regulated protein 78 (GRP78), glucose-6-phosphate dehydrogenase (G6PD), elongation factor 1γ (EF1γ), nucleolar and spindle-associated protein (NuSAP), and activator of 90 kDa heat shock protein ATPase homolog 1 (AHSA1). Western blotting also confirmed altered levels of PCNA, GRP78, and G6PD in NnV-treated HepG2 cells. In summary, the proteomic approach explains the mode of action of NnV as an anticancer agent. Further characterization of NnV may help to unveil novel therapeutic agents in cancer treatment.

Glucose 6-phosphate dehydrogenase and the kidney

PURPOSE OF REVIEW

Glucose 6-phosphate dehydrogenase (G6PD) is the rate-limiting enzyme of the pentose phosphate pathway. G6PD is the main source of the essential cellular reductant, NADPH. The purpose of this review is to describe the biochemistry of G6PD and NADPH, cellular factors that regulate G6PD, normal physiologic roles of G6PD, and the pathogenic role altered G6PD/NADPH plays in kidney disease.

RECENT FINDINGS

NADPH is required for many essential cellular processes such as the antioxidant system, nitric oxide synthase, cytochrome p450 enzymes, and NADPH oxidase. Decreased G6PD activity and, as a result, decreased NADPH level have been associated with diabetic kidney disease, altered nitric oxide production, aldosterone-mediated endothelial dysfunction, and dialysis-associated anemia. Increased G6PD activity is associated with all cancers including kidney cancer. Inherited G6PD deficiency is the most common mutation in the world that is thought to be a relatively mild disorder primarily associated with anemia. Yet, intriguing studies have shown an increased prevalence of diabetes mellitus in G6PD-deficient people. It is not known if G6PD-deficient people are at more risk for other diseases.

SUMMARY

Much more research needs to be done to determine the role of altered G6PD activity (inherited or acquired) in the pathogenesis of kidney disease.

miR-1 inhibits progression of high-risk papillomavirus-associated human cervical cancer by targeting G6PD

Ectopic glucose-6-phosphate dehydrogenase (G6PD) expression may contribute to tumorigenesis in cervical cancer associated with high-risk human papillomavirus (HR-HPV 16 and 18) infections. Here, we demonstrate that microRNA-1 (miR-1) in association with AGO proteins targets G6PD in HR-HPV-infected human cervical cancer cells. miR-1 inhibited expression of a reporter construct containing a putative G6PD 3′-UTR seed region and suppressed endogenous G6PD expression. Down-regulation of miR-1 increased G6PD expression in cervical cancer cells. Regression analysis revealed that miR-1 levels correlate negatively with the clinicopathologic features in HR-HPV 16/18-infected cervical cancer patients. miR-1 overexpression inhibited proliferation and promoted apoptosis in cervical cancer cells and reduced xenograft tumor growth in nude mice. Conversely, sponge-mediated miR-1 knockdown markedly increased viability and reduced apoptosis in cervical cancer cells and supported neoplasm growth. Restoration of G6PD expression partially reversed the effects of miR-1 overexpression both in vitro and in vivo. In addition, co-transfection of G6PD siRNA and miR-1 sponge partially reversed miR-1 sponge-induced reductions in cell viability and neoplasm growth. These results suggest that miR-1 suppresses the development and progression of HR-HPV 16/18-infected cervical cancer by targeting G6PD and may be a promising novel therapeutic candidate.

Deciphering the Role of the Barr Body in Malignancy: An insight into head and neck cancer

X chromosome inactivation is the epitome of epigenetic regulation and long non-coding ribonucleic acid function. The differentiation status of cells has been ascribed to X chromosome activity, with two active X chromosomes generally only observed in undifferentiated or poorly differentiated cells. Recently, several studies have indicated that the reactivation of an inactive X chromosome or X chromosome multiplication correlates with the development of malignancy; however, this concept is still controversial. This review sought to shed light on the role of the X chromosome in cancer development. In particular, there is a need for further exploration of the expression patterns of X-linked genes in cancer cells, especially those in head and neck squamous cell carcinoma (HNSCC), in order to identify different prognostic subpopulations with distinct clinical implications. This article proposes a functional relationship between the loss of the Barr body and the disproportional expression of X-linked genes in HNSCC development.

Control of the NADPH supply for oxidative stress handling in cancer cells

It has not been systematically analyzed whether the NADPH supply is a limiting factor for oxidative stress management in cancer cells. In the present work, it was determined in non-cancer and cancer cells the protein contents and kinetomics of (i) the cytosolic enzymes responsible for the NADPH production (i.e., Glc6PDH, 6PGDH, ME, IDH-1); and (ii) the two main enzymes responsible for NADPH/NADP⁺ and GSH/GSSG recycling (GR, GPx-1) associated to oxidative stress management. With these data, kinetic models were built and further validated. Rat liver and hepatoma AS-30D cytosolic fractions exhibited greater Vmax for IDH-1 than for Glc6PDH and 6PGDH whereas human cancer cells and platelets showed greater Vmax for Glc6PDH than for 6PGDH and IDH-1. The ME activity was comparatively low in all cell types tested. The Km values for the respective specific substrates were all similar among the different cell types. Most activities were lower in AS-30D cells than in liver. In contrast, IDH-1, Glc6PDH and GR activities in human cancer cells were similar or greater to those of platelets, but GPx-1 activity was severely suppressed, despite showing similar GPx-1 protein content vs. platelets. Kinetic analysis and pathway modeling revealed a previously unveiled feedback IDH-1 regulation by GSH. The oxidative stress management in cancer cells (i) was mainly controlled by GPx-1 and the main NADPH provider was Glc6PDH; and (ii) modeling indicated that NADPH supply was not a controlling step. These data suggested that Glc6PDH and GPx-1 are adequate and promising targets for anti-cancer therapeutic intervention.

Navβ2 knockdown improves cognition in APP/PS1 mice by partially inhibiting seizures and APP amyloid processing

Voltage-gated sodium channels beta 2 (Navβ2, encoded by SCN2B) is a substrate of β-site amyloid precursor protein cleaving enzyme 1 (BACE1) and regulates cell surface expression of channels in neurons. Previous studies reported enhanced Navβ2 processing by BACE1 in Alzheimer’s disease (AD) model and patients. We investigated whether changes in Navβ2 expression affect neuronal seizure and amyloid precursor protein (APP) processing in an AD mouse model. Our study used eight-month-old APP/presenilin 1 (PS1) mice and transgenic Navβ2 knockdown [by 61% vs. wild type (WT)] APP/PS1 mice (APP/PS1/Navβ2-kd), with age-matched WT and Navβ2 knockdown (Navβ2-kd) mice as controls. We found that Navβ2 knockdown in APP/PS1 mice partially reversed the abnormal Navβ2 cleavage and the changes in intracellular and total Nav1.1α expression. It also restored sodium currents density in hippocampal neurons and neuronal activity, as indicated by EEG tracing; improved Morris water maze performance; and shifted APP amyloidogenic metabolism towards non-amyloidogenic processing. There were no differences in these indicators between WT and Navβ2-kd mice. These results suggest Navβ2 knockdown may be a promising strategy for treating AD.

Overexpression of G6PD Represents a Potential Prognostic Factor in Clear Cell Renal Cell Carcinoma

Glucose-6-phosphate dehydrogenase (G6PD) participates in glucose metabolism and it acts as the rate-limiting enzyme of the pentose phosphate pathway (PPP). Recently, G6PD dysregulation has been found in a variety of human cancers. Through analyzing published data in The Cancer Genome Atlas (TCGA), our pilot study indicated that G6PD mRNA expression was significantly higher in advanced Fuhrman grade in clear cell renal cell carcinoma (ccRCC). These clues promoted us to further evaluate the expression profile of G6PD and its prognostic impact in patients with ccRCC. In this study, G6PD expression levels were analyzed in 149 human ccRCC and normal tissues using immunohistochemistry. The results showed that compared with that in the normal renal samples, G6PD was found highly expressed in 51.0% of ccRCC (p<0.05). High expression of G6PD was significantly correlated to tumor extent, lymph node metastasis, Fuhrman grade, and TNM stage of ccRCC (all p<0.05). Moreover, positive G6PD expression was associated with poorer overall survival in ccRCC (p<0.001). In Cox regression analyses, high expression of G6PD also could be an independent prognostic factor for overall survival in ccRCC (p=0.007). This study suggests that overexpression of G6PD is associated with advanced disease status and therefore may become an important prognosticator for poor outcomes in ccRCC, as well as a potential therapeutic target for developing effective treatment modalities.

Glucose-6-phosphate dehydrogenase expression is correlated with poor clinical prognosis in esophageal squamous cell carcinoma

Increasing evidence has demonstrated that glucose-6-phosphate dehydrogenase (G6PD), a key metabolic enzyme, participating in pentose phosphate pathway (PPP), is tightly associated with development and progression of a variety of tumors. Here, we reported expression of G6PD and its association with the prognosis of the patients with esophageal squamous cell carcinoma (ESCC). The results revealed significantly elevated G6PD mRNA and protein expressions in ESCC tissues compared with normal tissues (P < 0.05). Furthermore, high G6PD expression was tightly associated with histological grade, TNM staging and lymph node metastasis (P < 0.05), but not related to the patients' age and gender (P > 0.05). Importantly, the survival time of G6PD-positive patients was markedly lower than that of G6PD-negative patients (P < 0.05). Most notably, Cox multivariate assay demonstrated that G6PD was an independent prognostic factor for the patients with ESCC. In conclusion, G6PD may be a novel predictor for the prognosis of the patients with ESCC.