Overexpression of HPV16 E6/E7 mediated HIF-1α upregulation of GLUT1 expression in lung cancer cells

The emerging role of human papillomavirus in lung cancer

Lung cancer stands as one of the most lethal diseases and is the foremost cause of cancer-related mortalities worldwide. The pathophysiology of lung cancer is multifaceted, and it includes multiple cell signaling pathways and other complex factors such as oxidative stress and genetics. The association of HPV with lung carcinogenesis was first proposed in 1979, and since then, scientists worldwide have been putting forward several hypotheses to establish a relationship between this virus and lung cancer. Although studies have reported the presence of HPV in lung cancer, the exact mechanism of entry and the route of transmission have not been elucidated clearly till date. Numerous studies across the globe have detected differentially expressed HPV oncoproteins in lung cancer patients and found their association with the critical cell signaling pathways that leads to the development and progression of lung cancer. Many reports have also provided evidence stating the involvement of HPV in determining the survival status of lung cancer patients. The present review recapitulates the studies evincing the association of HPV and lung cancer, its route of transmission and mechanism of action; the detection of the virus and treatment opportunities for HPV-positive lung cancer; and the severity associated with this disease. Therefore, this will provide an explicit idea and would help to develop preventive measures and specific as well as effective treatment for HPV-associated lung carcinogenesis.

Bioinformatics Analysis Reveals E6 and E7 of HPV 16 Regulate Metabolic Reprogramming in Cervical Cancer, Head and Neck Cancer, and Colorectal Cancer through the PHD2-VHL-CUL2-ELOC-HIF-1α Axis

Human papillomavirus 16 (HPV 16) infection is associated with several types of cancer, such as head and neck, cervical, anal, and penile cancer. Its oncogenic potential is due to the ability of the E6 and E7 oncoproteins to promote alterations associated with cell transformation. HPV 16 E6 and E7 oncoproteins increase metabolic reprogramming, one of the hallmarks of cancer, by increasing the stability of hypoxia-induced factor 1 α (HIF-1α) and consequently increasing the expression levels of their target genes. In this report, by bioinformatic analysis, we show the possible effect of HPV 16 oncoproteins E6 and E7 on metabolic reprogramming in cancer through the E6-E7-PHD2-VHL-CUL2-ELOC-HIF-1α axis. We proposed that E6 and E7 interact with VHL, CUL2, and ELOC in forming the E3 ubiquitin ligase complex that ubiquitinates HIF-1α for degradation via the proteasome. Based on the information found in the databases, it is proposed that E6 interacts with VHL by blocking its interaction with HIF-1α. On the other hand, E7 interacts with CUL2 and ELOC, preventing their binding to VHL and RBX1, respectively. Consequently, HIF-1α is stabilized and binds with HIF-1β to form the active HIF1 complex that binds to hypoxia response elements (HREs), allowing the expression of genes related to energy metabolism. In addition, we suggest an effect of E6 and E7 at the level of PHD2, VHL, CUL2, and ELOC gene expression. Here, we propose some miRNAs targeting PHD2, VHL, CUL2, and ELOC mRNAs. The effect of E6 and E7 may be the non-hydroxylation and non-ubiquitination of HIF-1α, which may regulate metabolic processes involved in metabolic reprogramming in cancer upon stabilization, non-degradation, and translocation to the nucleus.

Aspartate-β-hydroxylase and hypoxia marker expression in head and neck carcinomas: implications for HPV-associated tumors

BACKGROUND

A proportion of head and neck carcinomas (HNSCCs) are induced by high-risk human papillomaviruses (HPVs) and are associated with better patient outcomes compared to patients with HNSCCs related to tobacco and alcohol abuse. In the microenvironment of solid tumors, including HNSCCs, oxygen levels are often reduced, and a hypoxic state is induced. This can lead to a poor treatment response and a worse patient prognosis. One of the hypoxia-responsive genes is aspartate-β-hydroxylase (ASPH), whose activity promotes the growth, invasiveness, and metastasis of many types of solid tumors.

METHODS

In our study, HNSCC samples were analyzed for the expression of ASPH and selected endogenous hypoxia markers by real-time PCR and/or multiplex fluorescence immunohistochemistry.

RESULTS

Except for the EPAS1 gene, which had higher mRNA expression in the HPV-negative group of HNSCC (p < 0.05), we found no other differences in the expression of the tested genes that were related to HPV status. On the contrary, a statistically significantly higher number of cells producing ASPH (p < 0.0001), HIF1A (p < 0.0001), GLUT1 (p < 0.0001), and MMP13 (p < 0.05) proteins were detected in the HPV-positive tumor group than in the HPV-negative sample group. All the evaluated markers, except for MMP9/13, were more abundant in the tumor parenchyma than in the tumor stroma. The Cox proportional hazard models showed that increased numbers of cells with GLUT1 and HIF1A protein expression were positive prognostic markers for overall and disease-specific survival in patients independent of HPV tumor status.

CONCLUSION

The study examined HNSCC samples and found that elevated ASPH and hypoxia marker proteins, typically associated with poor prognosis, may actually indicate active HPV infection, the strongest prognostic factor in HNSCC patients. In cases where HPV status is uncertain, increased expression of HIF1A and GLUT1 can serve as positive prognostic factors.

HPV16 E6 Oncogene Contributes to Cancer Immune Evasion by Regulating PD-L1 Expression through a miR-143/HIF-1a Pathway

Human Papillomaviruses have been associated with the occurrence of cervical cancer, the fourth most common cancer that affects women globally, while 70% of cases are caused by infection with the high-risk types HPV16 and HPV18. The integration of these viruses' oncogenes E6 and E7 into the host's genome affects a multitude of cellular functions and alters the expression of molecules. The aim of this study was to investigate how these oncogenes contribute to the expression of immune system control molecules, using cell lines with integrated HPV16 genome, before and after knocking out E6 viral gene using the CRISPR/Cas9 system, delivered with a lentiviral vector. The molecules studied are the T-cell inactivating protein PD-L1, its transcription factor HIF-1a and the latter's negative regulator, miR-143. According to our results, in the E6 knock out (E6KO) cell lines an increased expression of miR-143 was recorded, while a decrease in the expression of HIF-1a and PD-L1 was exhibited. These findings indicate that E6 protein probably plays a significant role in enabling cervical cancer cells to evade the immune system, while we propose a molecular pathway in cervical cancer, where PD-L1's expression is regulated by E6 protein through a miR-143/HIF-1a axis.

Reprogramming of glucose metabolism in virus infected cells

Viral infection is a kind of cellular stress that leads to the changes in cellular metabolism. Many metabolic pathways in a host cell such as glycolysis, amino acid and nucleotide synthesis are altered following virus infection. Both oncogenic and non-oncogenic viruses depend on host cell glycolysis for their survival and pathogenesis. Recent studies have shown that the rate of glycolysis plays an important role in oncolysis as well by oncolytic therapeutic viruses. During infection, viral proteins interact with various cellular glycolytic enzymes, and this interaction enhances the catalytic framework of the enzymes subsequently the glycolytic rate of the cell. Increased activity of glycolytic enzymes following their interaction with viral proteins is vital for replication and to counteract the inhibition of glycolysis caused by immune response. In this review, the importance of host cell glycolysis and the modulation of glycolysis by various viruses such as oncogenic, non-oncogenic and oncolytic viruses are presented.

The HPV16 E6, E7/miR-23b-3p/ICAT signaling axis promotes proliferation, migration, invasion and EMT of cervical cancer cells

Cervical cancer (CC) remains one of the most common female malignancies, with higher incidence and mortality rates. more than 99% of CCs are associated with persistent infection with high-risk human papillomavirus. In view of the growing evidence that HPV 16 E6 and E7, two key oncoproteins encoded by HPV 16, regulate the expression of many other multifunctional genes and downstream effectors that contribute to the development of CC. Herein, we undertook a comprehensive effort into how HPV16 E6, E7 oncogenes affect the progression of CC cells. Previous studies have shown that ICAT expression was significantly increased in CC and had a pro-cancer effect. We observed that knockdown of HPV16 E6, E7 expression in SiHa and CasKi cells resulted in significant inhibition of ICAT expression and upregulation of miR-23b-3p expression. Besides, dual luciferase assays confirmed that ICAT was a target gene of miR-23b-3p, and negatively modulated by miR-23b-3p. Functional experiments showed that the overexpression of miR-23b-3p suppressed malignant behaviors of CC cells, such as migration, invasion and EMT. The overexpression of ICAT counteracted the suppressive effect of miR-23b-3p on HPV16-positive CC cells. Furthermore, after the knockdown of HPV16 E6 and E7, the inhibition of miR-23b-3p could increase the ICAT expression and rescue the siRNA HPV16 E6, E7-mediated suppressive impact on the aggressiveness of SiHa and CaSki cells. Collectively, our findings uncover that HPV16 E6, E7/miR-23b-3p/ ICAT axis plays an important role in HPV16-positive CC pathogenesis, which may serve as a promising therapeutic target for HPV16-associated CC.

Targeting Mitochondrial Therapy in the Regulation of HPV Infection and HPV-Related Cancers

It has been previously proposed that some types of cancer cells reprogram their metabolic pathways, favoring the metabolism of glucose by aerobic glycolysis (Warburg effect) instead of oxidative phosphorylation, mainly because the mitochondria of these cells are damaged, thus displaying mitochondrial dysfunction. However, in several cancers, the mitochondria do not exhibit any dysfunction and are also necessary for the tumor’s growth and maintenance. Remarkably, if the mitochondria are dysfunctional, specific processes associated with the release of cytochrome c (cyt c), such as apoptosis, are significantly impaired. In these cases, cellular biotherapies such as mitochondrial transplantation could restore the intrinsic apoptotic processes necessary for the elimination of cancers. On the other hand, if the mitochondria are in good shape, drugs that target the mitochondria are a valid option for treating the related cancers. Famously, the mitochondria are targeted by the human papillomavirus (HPV), and HPV-related cancers depend on the host’s mitochondria for their development and progression. On the other hand, the mitochondria are also important during treatment, such as chemotherapy, since they are key organelles for the increase in reactive oxygen species (ROS), which significantly increases cell death due to the presence of oxidative stress (OS). In this way, the mitochondria in HPV infection and in the development of HPV-related cancer could be targeted to reduce or eliminate HPV infections or HPV-related cancers. To our knowledge, there was no previous review specifically focusing on this topic, so this work aimed to summarize for the first time the potential use of mitochondria-targeting drugs, providing molecular insights on the main therapeutics developed so far in HPV infection and HPV-related cancer. Thus, we reviewed the mechanisms associated with HPV-related cancers, with their early proteins and mitochondrial apoptosis specifically induced by different compounds or drugs, in which these molecules induce the production of ROS, the activation of proapoptotic proteins, the deactivation of antiapoptotic proteins, the loss of mitochondrial membrane potential (Δψm), cyt c release, and the activation of caspases, which are all events which lead to the activation of mitochondrial apoptosis pathways. This makes these compounds and drugs potential anticancer therapeutics that target the mitochondria and could be exploited in future biomedical strategies.

Association of human papillomavirus with breast cancer: a new perspective on an old debate

Breast cancer is a common cancer in the female population. Despite remarkable progress in the treatment of this cancer, its exact etiology is still unknown. Since the first evidence of an association between breast cancer and human papillomavirus (HPV) was provided in 1992, numerous studies have explored this subject but have reached contradictory results. In this review, the authors examine the existing evidence and hypotheses regarding the pathways whereby HPV infection can reach breast cells and the mediators linking HPV oncoproteins to breast cancer pathogenesis. Furthermore, the authors discuss contradictory findings regarding the association of HPV with breast cancer. Showing the link between HPV infection and increased genomic instability, reduced apoptosis, immune system dysfunction and progression of metastasis, the reviewed findings highlight the importance of active presence or history of HPV infection as a prognostic factor for breast tumor development.

Like Brothers in Arms: How Hormonal Stimuli and Changes in the Metabolism Signaling Cooperate, Leading HPV Infection to Drive the Onset of Cervical Cancer

Despite all precautionary actions and the possibility of using vaccinations to counteract infections caused by human papillomaviruses (HPVs), HPV-related cancers still account for approximately 5% of all carcinomas. Worldwide, many women are still excluded from adequate health care due to their social position and origin. Therefore, immense efforts in research and therapy are still required to counteract the challenges that this disease entails. The special thing about an HPV infection is that it is not only able to trick the immune system in a sophisticated way, but also, through genetic integration into the host genome, to use all the resources available to the host cells to complete the replication cycle of the virus without activating the alarm mechanisms of immune recognition and elimination. The mechanisms utilized by the virus are the metabolic, immune, and hormonal signaling pathways that it manipulates. Since the virus is dependent on replication enzymes of the host cells, it also intervenes in the cell cycle of the differentiating keratinocytes and shifts their terminal differentiation to the uppermost layers of the squamocolumnar transformation zone (TZ) of the cervix. The individual signaling pathways are closely related and equally important not only for the successful replication of the virus but also for the onset of cervical cancer. We will therefore analyze the effects of HPV infection on metabolic signaling, as well as changes in hormonal and immune signaling in the tumor and its microenvironment to understand how each level of signaling interacts to promote tumorigenesis of cervical cancer.

HPV16 E6 promotes cell proliferation, migration, and invasion of human cervical cancer cells by elevating both EMT and stemness characteristics

In most cases of cervical cancer, the high-risk of the disease is caused by the human papilloma virus (HPV). Surgery or radiation usually benefits patients with early cervical cancer, while the metastatic one is uncurable and new therapeutic strategies and approaches are required. In this study, HPV16 E6 silence or overexpression were carried out to evaluate the possible mechanisms of HPV16 E6 function in cervical cancer cells with different HPV16 E6 expression background. HPV16 E6-positive cervical cancer cell Siha exerts significantly stronger cell invasion and migration potentials than the HPV16 E6-negative C33A cells. HPV16 E6 silence significantly weakened the potentials of cell invasion and migration, cell proliferation and stemness characteristic in Siha cells. Meanwhile, the overexpression of HPV16 E6 effectively promoted the cell proliferation and stemness characteristic in C33A cells. Our data also indicated a positive association between HPV16 E6 and the levels of epithelial to mesenchymal transition (EMT), and cell stemness. The ectopic expression of OCT4 could effectively reverse the inhibitory roles of HPV16 E6 silence on cell migration, invasion, and stemness in Siha cells. More interestingly, we found that HPV16 E6 might promote the OCT4 expression by impairing the direct binding of p53 on the promoter and activate its transcription. Taken together, our results indicated that HPV16 E6 could promoted the potential cell proliferation, migration, and invasion of human cervical cancer cells by modulating EMT and cell stemness. Our data provide a novel mechanism for how HPV16 E6 acts as a key risk factor for cervical cancer development and progression. This article is protected by copyright. All rights reserved.

Human papillomavirus16 E6 but not E7 upregulates GLUT1 expression in lung cancer cells by upregulating thioredoxin expression

Background and objective: E6 and E7 proteins in human papillomavirus (HPV) 16 are major oncogenes in several types of tumors, including lung cancer. Previous studies have demonstrated that both E6 and E7 oncoproteins can upregulate GLUT1 protein and mRNA expression levels in lung cancer cells. Thus, the present study aimed to investigate the main differences in the molecular mechanisms of GLUT1 expression regulated by E6 and E7. Methods: The double directional genetic manipulation and immunofluorescence were performed to explore the molecular mechanism of E6 or E7 upregulating the expression of GLUT1 in H1299 and A549 cell lines. Results: The overexpression of E6 in well-established lung cancer cell lines upregulated thioredoxin (Trx) protein expression. Notably, plasmid transfection or small interfering RNA transfection with E7 had no regulatory effect on Trx expression. As an important disulfide reductase of the intracellular antioxidant system, Trx plays important role in maintaining oxidative stress balance and protecting cells from oxidative damage. The overexpression of Trx increased the activation of NF-κB by upregulating p65 expression and promoting p65 nuclear translocation, and further upregulated GLUT1 protein and mRNA expression levels. The results of the present study demonstrated that E6, but not E7, upregulated GLUT1 expression in lung cancer cells by activating NF-κB due to the participation of Trx. Conclusion: These results suggest that Trx plays an important role in the pathogenesis of HPV-associated lung cancer, and propose a novel therapeutic target for HPV-associated lung cancer.

Infection by High-Risk Human Papillomaviruses, Epithelial-to-Mesenchymal Transition and Squamous Pre-Malignant or Malignant Lesions of the Uterine Cervix: A Series of Chained Events?

Wound healing requires static epithelial cells to gradually assume a mobile phenotype through a multi-step process termed epithelial-to-mesenchymal transition (EMT). Although it is inherently transient and reversible, EMT perdures and is abnormally activated when the epithelium is chronically exposed to pathogens: this event deeply alters the tissue and eventually contributes to the development of diseases. Among the many of them is uterine cervical squamous cell carcinoma (SCC), the most frequent malignancy of the female genital system. SCC, whose onset is associated with the persistent infection of the uterine cervix by high-risk human papillomaviruses (HR-HPVs), often relapses and/or metastasizes, being resistant to conventional chemo- or radiotherapy. Given that these fearsome clinical features may stem, at least in part, from the exacerbated and long-lasting EMT occurring in the HPV-infected cervix; here we have reviewed published studies concerning the impact that HPV oncoproteins, cellular tumor suppressors, regulators of gene expression, inflammatory cytokines or growth factors, and the interactions among these effectors have on EMT induction and cervical carcinogenesis. It is predictable and desirable that a broader comprehension of the role that EMT inducers play in SCC pathogenesis will provide indications to flourish new strategies directed against this aggressive tumor.

Oncogenic Viruses as Entropic Drivers of Cancer Evolution

Viral infection is an indisputable causal factor for nearly 17% of all human cancers. However, the diversity and complexity of oncogenic mechanisms raises new questions as to the mechanistic role of viruses in cancer. Classical viral oncogenes have been identified for all tumor-associated viruses. These oncogenes can have multiple oncogenic activities that may or may not be utilized in a particular tumor cell. In addition, stochastic events, like viral mutation and integration, as well as heritable host susceptibilities and immune deficiencies are also implicated in tumorigenesis. A more contemporary view of tumor biology highlights the importance of evolutionary forces that select for phenotypes better adapted to a complex and changing environment. Given the challenges of prioritizing singular mechanistic causes, it may be necessary to integrate concepts from evolutionary theory and systems biology to better understand viral cancer-driving forces. Here, we propose that viral infection provides a biological “entropy” that increases genetic variation and phenotypic plasticity, accelerating the main driving forces of cancer cell evolution. Viruses can also influence the evolutionary selection criteria by altering the tumor microenvironment and immune signaling. Utilizing concepts from cancer cell evolution, population genetics, thermodynamics, and systems biology may provide new perspectives on viral oncogenesis and identify novel therapeutic strategies for treating viruses and cancer.

The Effect of GLUT1 on Survival Rate and the Immune Cell Infiltration of Lung Adenocarcinoma and Squamous Cell Carcinoma: A Meta and Bioinformatics Analysis

BACKGROUND

Lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC) are two major subtypes of non-small cell lung cancer (NSCLC). Studies have shown that abnormal expression of glucose transport type 1 (GLUT1) in NSCLC patients has been associated with progression, aggressiveness, and poor clinical outcome. However, the clinical effect of GLUT1 expression on LUAD and LUSC is unclear.

OBJECTIVE

This study aims to learn more about the character of GLUT1 in LUAD and LUSC.

METHODS

A meta-analysis was performed to evaluate the GLUT1 protein level, and bioinformatics analysis was used to detect the GLUT1 mRNA expression level, survival differences, and the infiltration abundance of immune cells in samples from TCGA. Meanwhile, functional and network analysis was conducted to detect important signaling pathways and key genes with the Gene Expression Omnibus (GEO) dataset.

RESULTS

Our results showed that GLUT1 was over-expressed both in LUAD and LUSC. LUAD patients with high GLUT1 expression had a poor prognosis. Additionally, GLUT1 was related to B cell and neutrophil infiltration of LUAD. In LUSC, GLUT1 was correlated with tumor purity, B cell, CD8⁺ T cell, CD4⁺ T cell, macrophage, neutrophil, and dendritic cell infiltration. The GEO dataset analysis results suggested GLUT1 potentially participated in the p53 signaling pathway and metabolism of xenobiotics by cytochrome P450 and was associated with KDR, TOX3, AGR2, FOXA1, ERBB3, ANGPT1, and COL4A3 gene in LUAD and LUSC.

CONCLUSION

GLUT1 might be a potential biomarker for aggressive progression and poor prognosis in LUAD, and a therapeutic biomarker in LUSC.

Expression and Clinical Significance of HKII and HIF-1α in Grade Groups of Prostate Cancer

Prostate cancer (PCA) is the second leading cause of cancer-related mortality in men. The glycolytic enzymes hexokinase II (HKII) and the major regulator hypoxia-inducible factor-1α (HIF-1α) are PCA-specific biomarkers. Some studies have shown that HKII and HIF-1α are highly expressive in PCA and are associated with the growth and metastasis of treatment. Whether HKII and HIF-1α regulate the different differentiation of PCA remains largely unknown. Therefore, the study aims to explore the value of HKII and HIF-1α in different grade groups of PCA. Our data indicated that compared with normal prostate tissues, the level of mRNA and protein of HKII and HIF-1α in PCA increased significantly, besides the results showed the high expression of HKII and HIF-1α had a tendency to promote the progression and differentiation of PCA. The study also found that HKII expression was positively correlated with the expression of HIF-1α. HKII and HIF-1α were related to the degree of differentiation PCA, especially in high-grade PCA. Furthermore, the high expression of HKII was significantly associated with Gleason score and histological differentiation in clinicopathological characteristics of patients with PCA. These results were further used to confirm that the expression of HKII and HIF-1α was associated with the progression and differentiation of PCA. These experiments indicated that HKII and HIF-1α might be novel biomarkers of PCA with potential clinical application value, provide a new potential target for PCA treatment, and are expected to be used for individualized treatment in patients with PCA.

Proteomic Alterations in Salivary Exosomes Derived from Human Papillomavirus-Driven Oropharyngeal Cancer

BACKGROUND

Increasing evidence supports the notion that human papillomavirus (HPV) DNA integration onto the human genome can influence and alter the molecular cargo in the exosomes derived from head and neck cancer cells. However, the molecular cargo of salivary exosomes derived from HPV-driven oropharyngeal cancer (HPV-driven OPC) remains unelucidated.

METHODS AND MATERIALS

Salivary exosomes morphology and molecular characterizations were examined using the nanoparticle tracking (NTA), western blot analysis, transmission electron microscopy (TEM) and mass spectrometry analysis.

RESULTS

We report that HPV16 DNA was detected (80%) in isolated salivary exosomes of HPV-driven OPC patients. Importantly, we demonstrate elevated protein levels of six main glycolytic enzymes [i.e., aldolase (ALDOA), glyceraldehye-3-phosphate dehydrogenase (GAPDH), lactate dehydrogenase A/B (LDHA and LDHB), phosphoglycerate kinase 1 (PGK1) and pyruvate kinase M1/2 (PKM)] in isolated salivary exosomes of HPV-driven OPC patients, suggesting a novel mechanism underlying the potential role of salivary exosomes in mediating the reciprocal interplay between glucose metabolism and HPV-driven OPC.

CONCLUSION

Our data demonstrate the potential diagnostic value of HPV16 DNA and glycolytic enzymes in salivary exosomes in discriminating healthy controls from HPV-driven OPC patients, thereby opening new avenues in the future for clinical translation studies.

Expression and Significance of HPV16 E6/E7 mRNAs in the Bronchial Brush and TBNA Cells of Patients With Small Cell Lung Cancer

BACKGROUND AND OBJECTIVE

Small cell lung cancer (SCLC) is characterized by rapid growth, strong invasion, and early metastasis. However, the cause of its occurrence remains unclear. High-risk HPV infection is closely related to the occurrence of non-small cell lung cancer and cervical small cell neuroendocrine carcinoma.

METHODS

The expression levels of E6 mRNA and E7 mRNA in HPV16 were detected by qRT-PCR in the bronchial brushing and transbronchial needle aspiration (TBNA) of 310 patients with lung cancer and with benign lung diseases. To make the design of this experiment scientific and reasonable, the expression levels in lung squamous cell carcinoma were taken as positive controls, while those in benign cells were taken as negative controls.

RESULTS

The expression levels of E6 mRNA and E7 mRNA in SCLC group were significantly higher than those in benign cell group and slight higher than those in squamous cell carcinoma group. The expression levels of E6 mRNA and E7 mRNA in the central type of SCLC were significantly higher than those in the peripheral type of SCLC.

CONCLUSIONS

We speculate that the occurrence of some small cell carcinoma is the same as that of some squamous cell carcinoma, which is closely related to HPV16 infection. The overexpression of E6 mRNA and E7 mRNA is in some benign lesion cells, which may be related to HPV transient infection.

HPV and Other Microbiota; Who's Good and Who's Bad: Effects of the Microbial Environment on the Development of Cervical Cancer-A Non-Systematic Review

Cervical cancer is responsible for around 5% of all human cancers worldwide. It develops almost exclusively from an unsolved, persistent infection of the squamocolumnar transformation zone between the endo- and ecto-cervix with various high-risk (HR) human papillomaviruses (HPVs). The decisive turning point on the way to persistent HPV infection and malignant transformation is an immune system weakened by pathobionts and oxidative stress and an injury to the cervical mucosa, often caused by sexual activities. Through these injury and healing processes, HPV viruses, hijacking activated keratinocytes, move into the basal layers of the cervical epithelium and then continue their development towards the distal prickle cell layer (Stratum spinosum). The microbial microenvironment of the cervical tissue determines the tissue homeostasis and the integrity of the protective mucous layer through the maintenance of a healthy immune and metabolic signalling. Pathological microorganisms and the resulting dysbiosis disturb this signalling. Thus, pathological inflammatory reactions occur, which manifest the HPV infection. About 90% of all women contract an HPV infection in the course of their lives. In about 10% of cases, the virus persists and cervical intra-epithelial neoplasia (CIN) develops. Approximately 1% of women with a high-risk HPV infection incur a cervical carcinoma after 10 to 20 years. In this non-systematic review article, we summarise how the sexually and microbial mediated pathogenesis of the cervix proceeds through aberrant immune and metabolism signalling via CIN to cervical carcinoma. We show how both the virus and the cancer benefit from the same changes in the immune and metabolic environment.

CPNE1 Enhances Colorectal Cancer Cell Growth, Glycolysis, and Drug Resistance Through Regulating the AKT-GLUT1/HK2 Pathway

Introduction

Colorectal cancer (CRC) is a major cause of cancer-related mortality worldwide. Copines-1 (CPNE1) has been shown to be overexpressed in various cancers; however, the role of CPNE1 in CRC remains unknown. Therefore, it is of great importance to elucidate the role of CPNE1 in CRC and its underlying mechanism of action.

Methods

CPNE1 expression in CRC tissues was measured by quantitative real-time PCR and immunohistochemical (IHC) staining. CPNE1 was knocked down (KD) or overexpressed using small inferring RNAs or lentiviral transduction in CRC cells. The proliferation, apoptosis, glycolysis, and mitochondrial respiration of CRC cells were assessed by cell counting kit-8, flow cytometry, and Xfe24 extracellular flux analyzer assays, respectively. The role of CPNE1 in tumor growth and chemoresistance was further confirmed in xenograft and patient-derived tumor xenograft models, respectively.

Results

CPNE1 mRNA and protein were upregulated in CRC tissues. CPNE1 promoted proliferation, inhibited apoptosis, increased mitochondrial respiration, enhanced aerobic glycolysis by activating AKT signaling, upregulated glucose transporter 1 (GLUT1) and hexokinase 2 (HK2), and downregulated the production of cleaved Caspase-3 (c-Caspase 3). CPNE1 also contributed to chemoresistance in CRC cells. CPNE1 KD inhibited tumor growth and increased the sensitivity of tumors to oxaliplatin in vivo.

Conclusion

CPNE1 promotes CRC progression by activating the AKT-GLUT1/HK2 cascade and enhances chemoresistance.

HPV 16 E6/E7 Promote the Glucose Uptake of GLUT1 in Lung Cancer Through Downregulation of TXNIP Due to Inhibition of PTEN Phosphorylation

High-risk human papillomavirus (HPV) infection play an important role in the development of lung cancer. Our previously study showed that E6 and E7 in HPV16 upregulated the expression of GLUT1 in lung cancer cells. However, whether they can promote the glucose uptake by GLUT1 and the underlying molecular mechanism has not been identified. It has been reported that thioredoxin interacting protein (TXNIP) regulates both the expression of GLUT1 and its glucose uptake. We speculate that high risk HPV16 infection may be closely related to TXNIP expression. Therefore, we associate HPV16 with TXNIP to explore the potential molecular mechanism of their regulation of GLUT1 expression and glucose uptake. Using double directional genetic manipulation in lung cancer cells, we showed that HPV16 E6/E7 proteins downregulated the expression of p-PTEN in lung cancer cells, the knockdown of PTEN further inhibited the expression of TXNIP, the inhibition of TXNIP further promoted the accumulation of HIF-1α by inhibiting the translocation of nuclear HIF-1α to the cytoplasm, and subsequently upregulated the expression of GLUT1 at the protein and mRNA levels. More interestingly, we found that the knockdown of TXNIP played a decisive role to promote the glucose uptake by GLUT1. Together, these findings suggested that the PTEN-TXNIP-HIF-1α axis might be related to the E6/E7-mediated expression of GLUT1 and its glucose uptake.

Oxygen Sensing and Viral Replication: Implications for Tropism and Pathogenesis

The ability to detect and respond to varying oxygen tension is an essential prerequisite to life. Several mechanisms regulate the cellular response to oxygen including the prolyl hydroxylase domain (PHD)/factor inhibiting HIF (FIH)-hypoxia inducible factor (HIF) pathway, cysteamine (2-aminoethanethiol) dioxygenase (ADO) system, and the lysine-specific demethylases (KDM) 5A and KDM6A. Using a systems-based approach we discuss the literature on oxygen sensing pathways in the context of virus replication in different tissues that experience variable oxygen tension. Current information supports a model where the PHD-HIF pathway enhances the replication of viruses infecting tissues under low oxygen, however, the reverse is true for viruses with a selective tropism for higher oxygen environments. Differences in oxygen tension and associated HIF signaling may play an important role in viral tropism and pathogenesis. Thus, pharmaceutical agents that modulate HIF activity could provide novel treatment options for viral infections and associated pathological conditions.

Possible Oncogenic Viruses Associated with Lung Cancer

Lung cancer is the most common cause of cancer death worldwide. Tobacco smoking is the most predominant etiology for lung cancer. However, only a small percentage of heavy smokers develop lung cancer, which suggests that other cofactors are required for lung carcinogenesis. Viruses have been central to modern cancer research and provide profound insights into cancer causes. Nevertheless, the role of virus in lung cancer is still unclear. In this article, we reviewed the possible oncogenic viruses associated with lung cancer.

HPV16 E6/E7 promote the translocation and glucose uptake of GLUT1 by PI3K/AKT pathway via relieving miR-451 inhibitory effect on CAB39 in lung cancer cells

Background

HPV16 E6/E7 proteins are the main oncogenes and only long-term persistent infection causes lung cancer. Our previous studies have shown that HPV16 E6/E7 protein up-regulates the expression of GLUT1 in lung cancer cells. However, whether E6 and E7 protein can promote the glucose uptake of GLUT1 and its molecular mechanism are unclear.

Methods

The regulatory relationships of E6 or E7, miR-451, CAB39, PI3K/AKT, and GLUT1 were detected by double directional genetic manipulations in lung cancer cell lines. Immunofluorescence and flow cytometry were used to detect the effect of CAB39 on promoting the translocation to the plasma membrane of GLUT1. Flow cytometry and confocal microscopy were performed to detect the glucose uptake levels of GLUT1.

Results

The overexpression both E6 and E7 proteins significantly down-regulated the expression level of miR-451, and the loss of miR-451 further up-regulated the expression of its target gene CAB39 at both protein and mRNA levels. Subsequently, CAB39 up-regulated the expression of GLUT1 at both protein and mRNA levels. Our results demonstrated that HPV16 E6/E7 up-regulated the expression and activation of GLUT1 through the HPV-miR-451-CAB39-GLUT1 axis. More interestingly, we found that CAB39 prompted GLUT1 translocation to the plasma membrane and glucose uptake, and this promotion depended on the PI3K/AKT pathway.

Conclusion

Our findings provide new evidence to support the critical roles of miR-451 and CAB39 in the pathogenesis of HPV-related lung cancer.

Human papillomavirus 16 (HPV 16) E6 but not E7 inhibits the antitumor activity of LKB1 in lung cancer cells by downregulating the expression of KIF7

BACKGROUND

The E6 and E7 proteins in human papillomavirus 16 (HPV 16) are the main oncogenes in the occurrence of lung cancer. In recent studies, we found that E6 and E7 downregulated the expression of LKB1 in lung cancer cells. However, it is still unclear how E6 and E7 regulate LKB1 in lung cancer cells.

METHODS

Double directional genetic manipulation and nuclear plasma separation technology were performed to explore the molecular mechanism of E6 and E7 inhibiting the antitumor activity of LKB1 in well-established lung cancer cell lines.

RESULTS

E6 but not E7 significantly downregulated the expression of tumor suppressor KIF7 at protein level, and the inhibition of KIF7 further reduced the expression of LKB1 both in the nuclei and in the cytoplasm, whereas reduced the expression of p-LKB1 in the cytoplasm only. This suggested that HPV 16 E6 but not E7 downregulates the antitumor activity of LKB1 by downregulating the expression of p-LKB1 in the cytoplasm only.

CONCLUSIONS

Here, we demonstrated for the first time that E6 but not E7 inhibits the antitumor activity of LKB1 in lung cancer cells by downregulating the expression of KIF7. Our findings provide new evidence to support the important role of KIF7 in the pathogenesis of lung cancer and suggests new therapeutic targets.

Metabolic regulation in HPV associated head and neck squamous cell carcinoma

Cancer cells exhibit distinct energy metabolic pathways due to multiple oncogenic events. In normoxia condition, the anaerobic glycolysis (Warburg effect) is highly observed in head and neck squamous cell carcinoma (HNSCC). HNSCC is associated with smoking, chewing tobacco, consumption of alcohol or Human Papillomavirus (HPV) infection primarily HPV16. In recent years, the correlation of HPV with HNSCC has significantly expanded. Despite the recent advancement in therapeutic approaches, the rate of HPV infected HNSCC has significantly increased in the last few years, specifically, in lower middle-income countries. The oncoproteins of High-risk Human Papillomavirus (HR-HPV), E6 and E7, alter the metabolic phenotype in HNSCC, which is distinct from non-HPV associated HNSCC. These oncoproteins, modulate the cell cycle and metabolic signalling through interacting with tumor suppressor proteins, p53 and pRb. Since, metabolic alteration represents a major hallmark for tumorigenesis, HPV acts as a source of biomarker linked to cancer progression in HNSCC. The dependency of cancer cells to specific nutrients and alteration of various metabolic associated genes may provide a unique opportunity for pharmacological intervention in HPV infected HNSCC. In this review, we have discussed the molecular mechanism (s) and metabolic regulation in HNSCC depending on the HPV status. We have also discussed the possible potential therapeutic approaches for HPV associated HNSCC through targeting metabolic pathways.

The role of monoamine oxidase A in HPV-16 E7-induced epithelial-mesenchymal transition and HIF-1α protein accumulation in non-small cell lung cancer cells

Our previous studies have found that human papillomavirus (HPV)-16 E7 oncoprotein promotes epithelial-mesenchymal transition (EMT) and hypoxia-inducible factor-1α (HIF-1α) protein accumulation in non-small cell lung cancer (NSCLC) cells and monoamine oxidase A (MAOA) is highly expressed in NSCLC tissues. Here, we further explored the role of MAOA in HPV-16 E7-induced EMT and HIF-1α protein accumulation in A549 and NCI-H460 NSCLC cells. Our results showed that HPV-16 E7 enhanced MAOA expression in NSCLC cells. Additionally, MAOA knockout inhibited HPV-16 E7-induced migration, invasion, and EMT, and significantly reduced HPV-16 E7-induced ROS generation and HIF-1α protein accumulation via promoting its degradation. Furthermore, MAOA knockout suppressed HPV-16 E7-induced ERK1/2 activation. In vivo, MAOA knockout inhibited tumor growth, metastasis, and the expression of EMT-related markers and HIF-1α proteins induced by HPV-16 E7 in NCI-H460 NSCLC subcutaneous xenograft and in situ intrapulmonary models of nude mice. Taken together, our findings provide evidence that MAOA plays a key role in EMT and HIF-1α protein accumulation induced by HPV-16 E7 in NSCLC cells, suggesting that MAOA may be a potential therapeutic target for HPV-related NSCLC.

USP53 promotes apoptosis and inhibits glycolysis in lung adenocarcinoma through FKBP51-AKT1 signaling

Despite an overall decline in the incidence of new cases, lung adenocarcinoma continues to be a leading cause of cancer death worldwide. Due to lack of gene expression signatures for risk and prognosis stratification of lung adenocarcinoma, identifying novel molecular biomarkers and therapeutic targets may potentially improve lung adenocarcinoma prognosis and treatment. In the current study, we investigate the role of USP53 in lung adenocarcinoma. Bioinformatics analysis, quantitative reverse transcription polymerase chain reaction, and Western blot were employed to examine patterns of gene expression in human lung adenocarcinoma database, patient samples, and cancer cell lines. Stable cell lines were produced by transducing with USP53 overexpression vector or short hairpin RNA targeting USP53 in the presence and absence of AKT pathway inhibitor LY294002. Functional assays were carried out to examine the impact of USP53 and AKT pathway on lung adenocarcinoma cell viability, apoptosis, and glycolysis in vitro, as well as tumor growth in vivo. The correlation between USP53 and FKBP51 was measured by coimmunoprecipitation and ubiquitination assay. Decreased USP53 levels are a reliable marker of lung adenocarcinoma across published datasets, clinical samples, and cell culture lines. Low USP53 expression is linked to decreased apoptosis and increased metabolic activity, suggesting it acts as a tumor suppressor. USP53 regulates cell apoptosis and glycolysis through the AKT1 pathway. Mechanistically, USP53 deubiquitinates FKBP51, which in turn dephosphorylates AKT1, and ultimately inhibits tumor growth in lung adenocarcinoma. Taken together, our study establishes USP53 as a novel regulator of AKT1 pathway with an important role in tumorigenesis in lung adenocarcinoma.

HPV16 E6/E7 upregulate hTERC mRNA and gene amplification levels by relieving the effect of LKB1 on Sp1 phosphorylation in lung cancer cells

Background:

There is an immediate need for research on the mechanism underlying telomerase activation and overexpression.

Materials & Methods:

A total of 174 patients with lung cancer (n = 106) and benign lung disease (n = 68) were recruited for the current study. The mRNA expression levels of E6, E7, LKB1, Sp1, and hTERC in brushing cells were detected by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), and hTERC amplification was also detected by fluorescence in situ hybridization (FISH). To investigate the potential mechanism, bidirectional genetic manipulation was performed in well-established lung cancer cell lines.

Results:

Our results indicated that the mRNA expression levels of E6, E7, Sp1, and hTERC and the amplification level of hTERC were significantly increased in the malignant group compared with those of the benign group (p < 0.01). Conversely, the mRNA expression level of LKB1 was significantly decreased in the malignant group (p < 0.01). The correlation between E6, E7, Sp1, and hTERC expression was positive but was negative with LKB1 (p < 0.01). Our results also showed that HPV16 E6/E7 downregulated the expression of LKB1 at both the protein and mRNA levels. The loss of LKB1 upregulated Sp1 expression, and also promoted Sp1 activity. Sp1 further upregulated hTERC at the mRNA and gene amplification levels. Thus, we proposed a HPV–LKB1–Sp1–hTERC axis of E6/E7 upregulation of hTERC expression.

Conclusion:

We demonstrated for the first time that E6 and E7 promoted hTERC mRNA expression and the amplification of hTERC by relieving the effect of LKB1 on the phosphorylation of Sp1. Sp1 further activated hTERC by directly binding to the promoter regions of hTERC.

A close relationship between HIF-1α expression and bone metastases in advanced NSCLC, a retrospective analysis

Background: Hypoxia-inducible factor (HIF-1) is a transcription factor produced in hypoxia condition, it is closely associated with tumor angiogenesis and metastasis. Aim: To investigate the expression of HIF-1α in relation with the presence or absence of bone metastasis. Methods A retrospective analysis was carried out on samples deriving from bronchial biopsy and CT-guided trans-thoracic needle biopsy. Detection of HIF-1 expression was performed on tissue sample by a monoclonal murine antibody, comparing patients with or without bone metastases (BM+). Findings: In the total population the main histotype was adenocarcinoma (71.5%), COPD the prevalent comorbidity (73.6%), the mean pack-year was 36.4. Ninety-five histology samples were considered for analysis and comparison. Subdividing the population according to the presence or not of bone metastases, significant differences were found in pack-years (p = 0.02), time to progression (TTP) (p = 0.001) and COPD comorbidity (p = 0.04). The survival comparison between the two subgroups obtained by Kaplan-Meier method showed a longer TTP in patients with visceral metastases with a HR of 1.3 though the comparison by this method was not significant (p = 0.1). A higher intensity and percentage of expression of HIF-1α was recorded in the group with bone metastases (p = 0.02). The main variable affecting HIF expression in a multivariate analysis was the presence of bone metastases (p = 0.01). Interpretation: Patients affected by NSCLC IV stage with bone metastasis have lower survival. There is a very close link between bone metastasis and HIF-1α expression level. The latter could be considered a predictive factor of bone spread and poor prognosis.

Leptin receptor mediates the proliferation and glucose metabolism of pancreatic cancer cells via AKT pathway activation

Pancreatic cancer (PC) is the fourth leading cause of cancer‑related mortality worldwide. Leptin is an adipokine that is significantly increased in obese patients and that functions in various biological processes of cancer, such as tumor growth and metastasis. However, its role in PC cell proliferation and glucose metabolism and the underlying mechanisms remain unclear. In the present study, in vitro leptin treatment significantly promoted cell proliferation and increased glucose uptake and lactate production of human PC and healthy pancreas cells in a dose‑dependent manner, accompanied by increased expression of the glycolytic enzymes hexokinase II and glucose transporter 1. Furthermore, leptin receptor‑specific short hairpin RNAs were used to silence leptin receptor expression in PC cells, which had the opposite effect to leptin stimulation and decreased AKT phosphorylation. In addition, the effects of leptin stimulation were significantly counteracted by the AKT inhibitor LY294002, whereas the effects of leptin silencing were counteracted by AKT activator insulin‑like growth factor 1. The results of the present study suggested that leptin may contribute to cell proliferation and glucose metabolism of human PC cells, which may be through activation of the AKT pathway.

Reprogramming of cellular metabolic pathways by human oncogenic viruses

Oncogenic viruses, like all viruses, relies on host metabolism to provide the metabolites and energy needed for virus replication. Many DNA tumor viruses and retroviruses will reprogram metabolism during infection. Additionally, some viral oncogenes may alter metabolism independent of virus replication. Virus infection and cancer development share many similarities regarding metabolic reprogramming as both processes demand increased metabolic activity to produce biomass: cell proliferation in the case of cancer and virion production in the case of infection. This review discusses the parallels in metabolic reprogramming between human oncogenic viruses and oncogenesis.

HPV 16 E6/E7 up-regulate the expression of both HIF-1α and GLUT1 by inhibition of RRAD and activation of NF-κB in lung cancer cells

Chronic infection of HPV16 E6/E7 is frequently associated with lung cancers, especially in non-smokers and in Asians. In our previous studies, we found that HPV16 E6/E7 up-regulated HIF-1α at protein level and further up-regulated GLUT1 at both protein and mRNA levels in well-established lung cancer cell lines. In one of our further mechanism study, the results demonstrated that HPV16 E6/E7 up-regulated the expression of GLUT1 through HPV-LKB1-HIF-1α-GLUT1 axis. However, there are multiple pathways involved in HPV16 E6/E7 regulation of HIF-1α expression. In current study, using double directional genetic manipulation in well-established lung cancer cell lines, we showed that both E6 and E7 down-regulated the expression of RRAD at both protein and mRNA levels. Like LKB1, RRAD is one of the cancer suppressor genes. The loss of RRAD further activated NF-κB by promoted cytoplasmic p65 translocated to nucleus, and up-regulated the expression level of the p-p65 in nucleus. Furthermore, p-p65 up regulated HIF-1α and GLUT1 at both protein and mRNA levels. Thus, we proposed HPV16 E6/E7 up-regulated the expression of GLUT1 through HPV-RRAD-p65- HIF-1α- GLUT1 axis. In conclusion, we demonstrated for the first time that E6 and E7 promoted the expression of HIF-1α and GLUT1 by relieving the inhibitory effect of RRAD which resulted in the activation of NF-κB by promoting cytoplasmic p65 translocated to nucleus, and up-regulated the expression of the p-p65 in nucleus in lung cancer cells. Our findings provided new evidence to support the critical role of RRAD in the pathogenesis of HPV-related lung cancer, and suggested novel therapeutic targets.

Differential effect of GLUT1 overexpression on survival and tumor immune microenvironment of human papilloma virus type 16-positive and -negative cervical cancer

Glucose transporter-1 (GLUT1) has been proposed as a prognosticator in various cancers associated with therapeutic resistance and immune evasion; however little data is available on the role of GLUT1 in cervical cancer. Most cervical cancers are caused by human papilloma virus (HPV), but studies on the treatment response and prognosis depending on the HPV subtype, are conflicting. This hypothesis-generating study aims to investigate the prognostic impact of GLUT1 in cervical cancer, in conjunction with HPV subtype. Clinicopathologic factors, along with mRNA expression data were obtained using The Cancer Genome Atlas database. Tumor HPV status and immune cell scores were extracted from previous publications. In total, 298 patients were analyzed. High GLUT1 expression was associated with old age, squamous cell carcinoma, high tumor stage, pelvic lymph node metastases, and low hysterectomy rate. Multivariate survival analysis revealed that high GLUT1 expression (Hazard ratio (HR) 2.57, p = 0.002) and HPV16 subtype (HR 0.56, p = 0.033) were independent prognostic factors for overall survival. In the subgroup analysis, poor prognostic impact of high GLUT1 expression was maintained in HPV16-positive group (p < 0.001), but not in HPV16-negative group (p = 0.495). Decreased immune cell scores of CD8⁺ T cells, B cells, and Th1 cells by high GLUT1 expression were observed only in HPV16-positive group. In conclusion, these results suggested that GLUT1 expression and HPV16 subtype might have an independent prognostic value in cervical cancer. GLUT1-mediated immunomodulation might be an important cause of treatment failure, especially in HPV16-positive group.

Glucose Transporter 1 Promotes the Malignant Phenotype of Non-Small Cell Lung Cancer through Integrin β1/Src/FAK Signaling

Background: Glucose transporter 1 (GLUT1) is the main factor of Warburg effect, which is associated with poor prognosis in many tumors. However, the underlying molecular mechanism of GLUT1 in the progression of non-small cell lung cancer (NSCLC) is unclear.

Methods: We used quantitative real-time PCR to detect GLUT1 mRNA expression in bronchial brushing samples and performed Western Blot and biological behavior testing to check the effect of GLUT1 on NSCLC cell proliferation, migration, invasion and apoptosis.

Results: We found that the C(t) normalized value of GLUT1 in malignant bronchial brushing samples was significantly higher than that in benign samples (P<0.05). GLUT1 significantly increased the expressions of cyclin A, cyclin D1, cyclin E, cyclin dependent kinase 2 (CDK2), CDK4, CDK6 and matrix metalloproteinase 2 (MMP2), but decreased the expressions of p53 and p130 in NSCLC cells. The biological behavior testing indicated that GLUT1 enhanced NSCLC cell proliferation, invasion and migration but inhibited cell apoptosis. In addition, GLUT1 upregulated the expression of integrin β1 and promoted the phosphorylation of focal adhesion kinase (FAK, phosphorylation at Tyr576/577) and Src (Src phosphorylation at Tyr530). siRNA knock down of integrin β1 expression suppressed GLUT1 induced NSCLC cell biological behavior, as well as the phosphorylation of FAK and Src.

Conclusion: Taken together, our data confirms that GLUT1 promotes the malignant phenotype of NSCLC through integrin β1/Src/FAK signaling, which provides a new therapeutic target for the treatment and research of lung cancer.

Human papillomavirus and lung cancer: an overview and a meta-analysis

PURPOSE

This review is devoted to assessing the prevalence of human papillomavirus (HPV) in lung cancer (LC) in the world. HPV is recognized as the etiological factor of cervical cancer, however, there is widespread evidence that this virus is detected not only in gynecological carcinomas, but also in tumors of other organs, in particular the upper respiratory tract and digestive tract.

MATERIALS AND METHODS

 A search was conducted to a depth of 29 years in the PubMed, Web of Science, Scopus, databases. The review includes 95 articles.

RESULTS

Of all the analyzed studies (9195 patients), 12 works showed a complete absence of HPV in the biological material in patients with LC. The absence of a virus among lung cancer patients has been established for Canada, the Netherlands and Singapore. The highest average percent of occurrence of this virus is shown for such countries as: Brazil, Korea, Greece and Taiwan (more than 40%). But the highest percentage of HPV occurrence by region is observed in Latin America (33.5%), followed by the Asian countries (31%), in European countries the frequency is 18%. Interestingly, the highest occurrence of high oncogenic types (16 and 18) is observed in Asia (40.3%), then in Latin America (33.6%), Europe (25.6%) and North America (15.4%). Low-oncogenic types (6 and 11) are also predominantly observed in Asia (39.9%), while in Europe and North America 30% and 12.8%, respectively. A meta-analysis of the prevalence of HPV was conducted using Comprehensive Meta-Analysis 3.0. Program, which included 26 studies, the results of which revealed: the prevalence of HPV infection in tumor lung tissue was compared with normal lung tissue OR (95% CI) = 5.38 (3.21-9.00) p < 0.0001, significance was also found for Chinese studies OR = 6.3, 95% CI 3.42-11.53, p < 0.0001, I2 = 71.8% and for nine studies in Europe OR = 6.3, 95% CI 1.8-22.18, p = 0.004, I2 = 51.0%. However, given the fact that the frequency of occurrence of HPV in lung tumor tissue varies greatly, a question may arise about the real role of HPV in LC carcinogenesis, which makes further research relevant and promising.

Correlation and expression analysis of hypoxia-inducible factor 1α, glucose transporter 1 and lactate dehydrogenase 5 in human gastric cancer

The development and identification of novel potential targeting sites for intervention therapy are essential in the search for improved treatment methods for gastric cancer (GC). Previously, it has been reported that hypoxia inducible factor-1α (HIF-1α) is a potential target gene involved in the endogenous hypoxic response and bioenergetic metabolism of GC cells. In the present study, with the assumption of a close interplay among HIF-1α, glucose transporter 1 (GLUT1) and lactate dehydrogenase-5 (LDH-5), 85 patients with GC were recruited and the protein and gene expression levels of HIF-1α, GLUT1 and LDH-5 in tumor tissues were evaluated in order to assess clinical correlations and co-expression patterns, using Immunohistochemical staining and reverse transcription-quantitative polymerase chain reaction. The results demonstrated that the protein and gene expression levels of HIF-1α were significantly associated with the depth of invasion, nodal metastasis, clinical stage, differentiation and distant metastasis. Consistent with the protein expression results, the mRNA expression levels of the genes coding for GLUT1 and LDH-5 were clearly associated with tumor size, depth of invasion, distant metastasis, clinical stage and differentiation. Correlation analysis of HIF-1α with GLUT1 and LDH-5 at the protein and mRNA expression levels in gastric carcinoma indicated that HIF-1α expression was positively correlated with the expression of GLUT1 (P<0.01, r=0.765 for mRNA expression; P<0.01, r=0.697 for protein expression) and LDH-5 (P<0.01, r=0.892 for mRNA expression; P<0.01, r=0.783 for protein expression) at the mRNA and protein levels. Therefore, it may be concluded that HIF-1α, GLUT1 and LDH-5 are potential target genes involved in the endogenous tumor response to hypoxia and the inhibition of tumor energy metabolism, highlighting a novel therapeutic target for GC.

Proliferating tumor cells mimick glucose metabolism of mature human erythrocytes

Mature human erythrocytes are dependent on anerobic glycolysis, i.e. catabolism (oxidation) of one glucose molecule to produce two ATP and two lactate molecules. Proliferating tumor cells mimick mature human erythrocytes to glycolytically generate two ATP molecules. They deliberately avoid or switch off their respiration, i.e. tricarboxylic acid (TCA) cycle and oxidative phosphorylation (OXPHOS) machinery and consequently dispense with the production of additional 36 ATP molecules from one glucose molecule. This phenomenon is named aerobic glycolysis or Warburg effect. The present review deals with the fate of a glucose molecule after entering a mature human erythrocyte or a proliferating tumor cell and describes why it is useful for a proliferating tumor cell to imitate a mature erythrocyte. Blood consisting of plasma and cellular components (99% of the cells are erythrocytes) may be regarded as a mobile organ, constantly exercising a direct interaction with other organs. Therefore, the use of drugs, which influences the biological activity of erythrocytes, has an immediate effect on the entire organism.

Abbreviations: TCA: tricarboxylic acid cycle; OXPHOS: oxidative phosphorylation; GSH: reduced state of glutathione; NFκB: Nuclear factor of kappa B; PKB (Akt): protein kinase B; NOS: nitric oxide synthase; IgG: immune globulin G; H₂S: hydrogen sulfide; slanDCs: Human 6-sulfo LacNAc-expressing dendritic cells; IL-8: interleukin-8; LPS: lipopolysaccharide; ROS: reactive oxygen species; PPP: pentose phosphate pathway; NADPH: nicotinamide adenine dinucleotide phosphate hydrogen; R5P: ribose-5-phophate; NAD: nicotinamide adenine dinucleotide; FAD: flavin adenine dinucleotide; O₂^●−: superoxide anion; G6P: glucose 6-phosphate; HbO₂: Oxyhemoglobin; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GAP: glyceraldehyde-3-phosphate; 1,3-BPG: 1,3-bis-phosphoglycerate; 2,3-BPG: 2,3-bisphosphoglycerte; PGAM1: phosphoglycerate mutase 1; 3-PG: 3-phosphoglycerate; 2-PG: 2-phosphoglycerate; MIPP1: Multiple inositol polyphosphate phosphatase; mTORC1: mammalian target of rapamycin complex 1; Ru5P: ribulose 5-phosphate; ox-PPP: oxidative branch of pentose phosphate pathway; PGK: phosphoglycerate kinase; IFN-γ: interferon-γ; LDH: lactate dehydrogenase; STAT3: signal transducer and activator of transcription 3; Rheb: Ras homolog enriched in Brain; H₂O₂: hydrogen peroxide; ROOH: lipid peroxide; SOD: superoxide dismutase; MRC: mitochondrial respiratory chain; MbFe²⁺-O₂: methmyoglobin; RNR: ribonucleotide reductase; PRPP: phosphoribosylpyrophosphate; PP_i: pyrophosphate; GSSG: oxidized state of glutathione; non-ox-PPP: non-oxidative branch of pentose phosphate pathway; RPI: ribose-5-phosphate isomerase; RPE: ribulose 5-phosphate 3-epimerase; X5P: xylulose 5-phosphate; TK: transketolase; TA: transaldolase; F6P: fructose-6-phosphate; AR2: aldose reductase 2; SD: sorbitol dehydrogenase; HK: hexokinase; MG: mehtylglyoxal; DHAP: dihydroxyacetone phosphate; TILs: tumor-infiltrating lymphocytes; MCTs: monocarboxylate transporters; pHi: intracellular pH; Hif-1α: hypoxia-induced factor 1; NHE1: sodium/H⁺ (Na⁺/H⁺) antiporter 1; V-ATPase: vacuolar-type proton ATPase; CAIX: carbonic anhydrase; CO₂: carbon dioxide; HCO₃⁻: bicarbonate; NBC: sodium/bicarbonate (Na⁺/HCO₃⁻) symporter; pHe: extracellular pH; GLUT-1: glucose transporter 1; PGK-1: phosphoglycerate kinase 1

Anti-tumor effect of aloe-emodin on cervical cancer cells was associated with human papillomavirus E6/E7 and glucose metabolism

Background：Aloe-emodin, an anthraquinone present in aloe latex, has been shown to have anti-proliferative properties in cervical cancer disease, all cases of which are almost caused by human papillomavirus (HPV), with the products of E6/E7. It is suggested that aloe-emodin may play an important role in HPV-induced cervical cancer cells.

Methods：Hela and SiHa cells were treated with various concentrations of aloe-emodin. MTT assay and flow cytometry were used to identify the cell growth and apoptosis. The expressions of HPV E6, E7 and GLUT1 (glucose transporter-1) were detected by real-time quantitative polymerase chain reaction (qRT-PCR) and Western blot (WB). The glucose uptake, lactate production and ATP production in HeLa and SiHa cells were also investigated.

Result：The results indicate that aloe-emodin promoted the apoptosis of HeLa and SiHa cells and decreased the expressions of HPV-related protein E6 and E7. Furthermore, aloe-emodin inhibited glucose metabolism by reducing GLUT1 expression. Overexpression of GLUT1 significantly weakened the apoptosis induced by aloe-emodin in HeLa cells.

Conclusion：In this study, we found that aloe-emodin induce apoptosis of cervical cancer cells, which was associated with HPV E6 and E7 and glucose metabolism.

Involvement of HPV Infection in the Release of Macrophage Migration Inhibitory Factor in Head and Neck Squamous Cell Carcinoma

Human papilloma virus (HPV) infection has been well-established as a risk factor in head and neck squamous cell carcinoma (HNSCC). The carcinogenic effect of HPV is mainly due to the E6 and E7 oncoproteins, which inhibit the functions of p53 and pRB, respectively. These oncoproteins could also play a role in the Warburg effect, thus favoring tumor immune escape. Here, we demonstrated that the pro-inflammatory cytokine macrophage migration inhibitory factor (MIF) is expressed at higher levels in HPV-negative patients than in HPV-positive patients. However, the secretion of MIF is higher in HPV-positive human HNSCC cell lines, than in HPV-negative cell lines. In-HPV positive cells, the half inhibitory concentration (IC50) of MIF inhibitor (4-iodo-6-phenylpyrimidine (4-IPP)) is higher than that in HPV-negative cells. This result was confirmed in vitro and in vivo by the use of murine SCCVII cell lines expressing either E6 or E7, or both E6 and E7. Finally, to examine the mechanism of MIF secretion, we conducted proton nuclear magnetic resonance (¹H-NMR) experiments, and observed that lactate production is increased in both the intracellular and conditioned media of HPV-positive cells. In conclusion, our data suggest that the stimulation of enzymes participating in the Warburg effect by E6 and E7 oncoproteins increases lactate production and hypoxia inducible factor 1α (HIF-1α) expression, and finally induces MIF secretion.

Oncogenic virus-induced aerobic glycolysis and tumorigenesis

Enhanced glycolysis under normoxic conditions is known as aerobic glycolysis or the Warburg effect and is a hallmark of many tumors. Viral infection may also induce aerobic glycolysis as it is required for replication and survival. Tumor viruses inducing aerobic glycolysis and lactate production during latent infection suggest a potential role of virus-induced glycolysis in tumorigenesis. Virus or virus-encoded proteins regulate glucose uptake and lactate export, increase the activity of glycolytic enzymes, and modulate glucose metabolic signals. Accumulating evidence suggests that virus-induced glycolysis may facilitate cell growth, transformation, migration, and invasion, but its significance in tumorigenesis remains unclear. We summarize the effects of oncogenic viruses on the metabolic shift to aerobic glycolysis and discuss the possible association of this metabolic reprogramming with tumor development and progression.

PI3K/Akt/HIF-1α signaling pathway mediates HPV-16 oncoprotein-induced expression of EMT-related transcription factors in non-small cell lung cancer cells

Background: Our previous studies have demonstrated that human papillomaviruse (HPV)-16 oncoproteins promoted epithelial-mesenchymal transition (EMT), leading to non-small cell lung cancer (NSCLC) progression, but the underlying molecular mechanisms still remain unclear. PI3K/Akt/HIF-1α signaling pathway has been reported to mediate hypoxia-induced EMT. In this study, we further explored the role of PI3K/Akt/HIF-1α signaling pathway in HPV-16 oncoprotein-induced EMT in NSCLC cells.

Methods: A549 and NCI-H460 NSCLC cells were transiently transfected with pEGFP-HPV-16 E6 or E7 constructs. Western blotting and RT-qPCR were respectively performed to determine the protein and mRNA expression of EMT-related transcription factors. HPV-16 E6 or E7-transfected NSCLC cells were co-transfected with specific HIF-1α-siRNA or pretreated with different concentrations of LY294002, a specific PI3K inhibitor, followed by the analysis of expression of EMT-related transcription factors. The correlation between HIF-1α and EMT-related transcription factors in NSCLC tissues was analyzed by immunohistochemical staining and Spearman rank correlation coefficient.

Results: HPV-16 E6 and E7 oncoproteins upregulated the expression of Slug and Twist1, the EMT-related transcription factors, at both protein and mRNA levels in A549 and NCI-H460 cells. The co-transfection with specific HIF-1α-siRNA, but not the non-specific (NS)-siRNA, significantly abrogated HPV-16 oncoprotein-induced upregulation of ZEB1, Snail1, Slug, and Twist1 at both protein and mRNA levels. Additionally, pretreatment with LY294002 obviously blocked HPV-16 E6- and E7-induced Snail1, Slug, and Twist1 protein expression in A549 and NCI-H460 cells. Further analysis of clinical specimens showed that HIF-1α protein was strongly expressed in NSCLC tissues, which was positively correlated with ZEB1, Snail1, Slug, and Twist1 protein expression.

Conclusions: PI3K/Akt/HIF-1α may contribute to the progression of HPV-associated NSCLC via mediating the expression of EMT-related transcription factors in NSCLC cells.

Regulation of Cellular Metabolism by High-Risk Human Papillomaviruses

The alteration of glucose metabolism is one of the first biochemical characteristics associated with cancer cells since most of these cells increase glucose consumption and glycolytic rates even in the presence of oxygen, which has been called &ldquo;aerobic glycolysis” or the Warburg effect. Human papillomavirus (HPV) is associated with approximately 5% of all human cancers worldwide, principally to cervical cancer. E6 and E7 are the main viral oncoproteins which are required to preserve the malignant phenotype. These viral proteins regulate the cell cycle through their interaction with tumor suppressor proteins p53 and pRB, respectively. Together with the viral proteins E5 and E2, E6 and E7 can favor the Warburg effect and contribute to radio- and chemoresistance through the increase in the activity of glycolytic enzymes, as well as the inhibition of the Krebs cycle and the respiratory chain. These processes lead to a fast production of ATP obtained by Warburg, which could help satisfy the high energy demands of cancer cells during proliferation. In this way HPV proteins could promote cancer hallmarks. However, it is also possible that during an early HPV infection, the Warburg effect could help in the achievement of an efficient viral replication.

Combined Inhibitions of Glycolysis and AKT/autophagy Can Overcome Resistance to EGFR-targeted Therapy of Lung Cancer

Efficacy of EGFR-targeted tyrosine kinase inhibitors (TKIs), such as erlotinib, to treat human non-small cell lung cancers (NSCLCs) with activating mutations in EGFR is not persistent due to drug resistance. Reprogramming in energy (especially glucose) metabolism plays an important role in development and progression of acquired resistance in cancer cells. We hypothesize that glucose metabolism in EGFR-TKI sensitive HCC827 cells and erlotinib-resistant sub-line of HCC827 (which we name it as erlotinib-resistant 6, ER6 cells in this study) is different and targeting glucose metabolism might be a treatment strategy for erlotinib-resistant NSCLCs. In this study, we found increased glucose uptakes, significant increase in glycolysis rate and overexpression of glucose transporter 1 in ER6 cells compared to its parental cells HCC827. We also found AKT and autophagy of ER6 cells were more activated than HCC827 cells after glucose starvation. Combining glucose deprivation and AKT or autophagy inhibitor could synergize and overcome the acquired resistance against EGFR-targeted therapy for NSCLCs. Our data suggest that the combinations of inhibitors of AKT or autophagy together with glucose deprivation could be novel treatment strategies for NSCLC with acquired resistance to targeted therapy.

The association between human papillomavirus infection and lung cancer: a system review and meta-analysis

To estimate the global attributable fraction of human papillomavirus (HPV) in lung cancer, we provided updated information through a system review and meta-analysis. We did a literature search on PubMed, Ovid and Web of Science to identify case-control studies and cohort studies that detected HPV in lung carcinomas. We included studies that tested 30 or more cases and were published before Feb 28, 2017. We collected information about gender, smoking status, HPV detection methods, HPV types, materials and clinical features. If it was not possible to abstract the required information directly from the papers, we contacted the authors. A meta-analysis was performed to calculate the pooled effect sizes (OR/RR) with 95% confidence intervals (CI) including subgroup analysis and meta-regression to explore sources of heterogeneity, by Stata 13.0 software. 36 case-control studies, contributing data for 6,980 cases of lung cancer and 7,474 controls from 17 countries and one cohort study with 24,162 exposed and 1,026,986 unexposed from China were included. HPV infection was associated with cancer of lung, pooled OR was 3.64 (95% CI: 2.60–5.08), calculated with the random-effects model. Pooled OR for allogeneic case-control studies, self-matched case-control studies and nested case-control studies were 6.71 (95% CI: 4.07–11.07), 2.59 (95% CI: 1.43–4.69) and 0.92 (95% CI: 0.63–1.36), respectively. Pooled OR for HPV 16 and HPV 18 infection, were 3.14 (95% CI: 2.07–4.76) and 2.25 (95% CI: 1.49–3.40), respectively. We also found that HPV infection may be associated with squamous cell carcinoma, adenocarcinoma and small cell carcinoma. There is evidence that HPV infection, especially HPV 16 and HPV 18 infection, significantly increase the risk of lung cancer. Future research needs to focus attention toward whether an HPV vaccine can effectively reduce the incidence of lung cancer.

Long-term persistent infection of HPV 16 E6 up-regulate SP1 and hTERT by inhibiting LKB1 in lung cancer cells

HPV 16 E6 upregulates hTERT expression in lung cancer cells. However, the underlying molecular mechanism is unclear. In this paper, E6, LKB1, SP1, and hTERT mRNA expression levels were detected in brushing cells of patients with lung cancer (n = 106) and with benign lung disease (n = 68) by qRT-PCR. The mRNA expression levels of E6, SP1, and hTERT were significantly increased in the malignant group compared with the benign group (P < 0.01). Conversely, the mRNA expression level of LKB1 was significantly decreased in the malignant group (P < 0.01). Furthermore, the correlation between E6, Sp1, hTERT, and LKB1 was performed, our results indicated that E6, Sp1, and hTERT with positive, but LKB1 with negative correlation (P < 0.01). To investigate the potential relationship between these genes, using double directional genetic manipulation, we showed that overexpression of E6 in H1299 cells down-regulated LKB1 mRNA and protein expression but up-regulated SP1 and hTERT as well as the transcriptional activity of Sp1. In contrast, knockdown of E6 in A549 cells by short-interference RNAs (siRNAs) up-regulated LKB1 expression, but down-regulated SP1 and hTERT expression as well as Sp1 activity. LKB1 loss upregulated both SP1 and hTERT at the protein and mRNA level as well as SP1 activity. To verify that the role of E6 on hTERT was mediated by SP1, siRNA knockdown of SP1 was performed on both H1299 and A549 cell lines. Inhibition of SP1 downregulated hTERT expression. Our results indicate that HPV16 E6 indirectly upregulated the expression of hTERT by inhibition of LBK1 expression and upregulation of Sp1 expression, thus suggesting a HPV-LKB1-SP1-hTERT axis for the tumorigenesis of lung cancer. Our study also provides new evidence to support the critical role of SP1 and LKB1 in the pathogenesis of HPV-related lung cancer, and suggests novel therapeutic targets.

KRAS/BRAF基因与结肠癌糖代谢研究现状

正电子发射断层成像术(positron emission tomography, PET)/计算机断层扫描(computed tomography, CT)显像可用于结肠癌的诊断、监测疗效和预后评估. ¹⁸F标记葡萄糖(2-fluorine-18-fluoro-2-deeoxy-D-glucose, ¹⁸F-FDG)是PET/CT常用显像剂, 可以反映结肠癌活体组织葡萄糖代谢. KRAS/BRAF基因检测常用于结肠癌靶向治疗方案的选择及评估其治疗效果. 文献报道¹⁸F-FDG-PET/CT显像可预测结肠癌KRAS/BRAF基因状态, 能以无创的方式预测结肠癌抗表皮生长因子受体靶向治疗效果. 目前国内有关KRAS/BRAF基因与结肠癌糖代谢的研究相对较少, 本文结合近期的相关文献进行概述.

HPV16 E6/E7 upregulates HIF-2α and VEGF by inhibiting LKB1 in lung cancer cells

Long-term persistent infection of HPV16 E6/E7 is frequently associated with lung cancers, especially in non-smokers and in Asians. However, molecular mechanisms of HPV16 E6/E7 induction of lung cancer are not fully understood. Using bi-directional genetic manipulation and four well-established lung cancer cell lines, we showed HPV16 E6/E7 downregulated expression of liver kinase B1 at both protein and messenger RNA levels; liver kinase B1 downregulated hypoxia-inducible factor 2α at protein level but not at messenger RNA level, and hypoxia-inducible factor 2α upregulated vascular endothelial growth factor at both protein and messenger RNA levels. This is the first study to show hypoxia-inducible factor 2α as a downstream effector of liver kinase B1 in lung cancer cells. Our results indicate that HPV16 E6/E7 indirectly upregulated the expression of vascular endothelial growth factor by inhibition of liver kinase B1 expression and upregulation of hypoxia-inducible factor 2α expression, thus propose a human papillomavirus-liver kinase B1-hypoxia-inducible factor 2α-vascular endothelial growth factor axis for the tumorigenesis of lung cancer. Our study also provides new evidence to support the critical role of liver kinase B1 in the pathogenesis of human papillomavirus-related lung cancer and suggests novel therapeutic targets.

CREB1 regulates glucose transport of glioma cell line U87 by targeting GLUT1

Glioma is stemmed from the glial cells in the brain, which is accounted for about 45% of all intracranial tumors. The characteristic of glioma is invasive growth, as well as there is no obvious boundary between normal brain tissue and glioma tissue, so it is difficult to resect completely with worst prognosis. The metabolism of glioma is following the Warburg effect. Previous researches have shown that GLUT1, as a glucose transporter carrier, affected the Warburg effect, but the molecular mechanism is not very clear. CREB1 (cAMP responsive element-binding protein1) is involved in various biological processes, and relevant studies confirmed that CREB1 protein regulated the expression of GLUT1, thus mediating glucose transport in cells. Our experiments mainly reveal that the CREB1 could affect glucose transport in glioma cells by regulating the expression of GLUT1, which controlled the metabolism of glioma and affected the progression of glioma.

Response to Intravenous Glucose-Tolerance Test and Risk of Cancer: A Long-Term Prospective Cohort Study

Background

Impaired glucose regulation, measured with an oral glucose-tolerance test, has been associated with the risk of cancer. Here, we explored whether the response to an intravenous glucose-tolerance test (IVGTT) is associated with the risk of cancer.

Methods

A cohort of 945 healthy men, aged 40–59 years in 1972–75, was followed for 40 years. An IVGTT was performed at baseline. Blood samples for glucose determinations were drawn immediately before glucose injection and thereafter every 10 min for 1 h. Associations were assessed with incidence rate ratios (IRR) and Cox models.

Findings

Cancer incidence was higher among men with 10-min glucose levels below the median than in men with levels above the median (IRR: 1.5, 95% CI: 1.2–1.9). This association remained significant after adjusting for relevant confounders (HR: 1.6, 95% CI: 1.3–2.1) and when excluding the first 10 years of follow-up to minimize the possibility of reverse causality (HR: 1.5, 95% CI: 1.2–2.0).

Interpretation

Healthy middle-aged males that responded to an intravenous glucose injection with rapid glucose elimination during the first phase had an elevated risk of cancer during 40 years of follow-up. First phase response to a glucose load might be related to cancer development.

•

Rapid elimination of plasma glucose during the first phase response was associated with a 60% elevated risk of cancer

•

Plasma glucose uptake during the first-phase may depend on the effectiveness of the molecular glucose-sensing apparatus

•

Polymorphisms critical for glucose transport into normal cells may also be crucial for transporting glucose into cancer cells

In this study low levels of plasma glucose in the early phase of an intravenous glucose-tolerance test were associated with a 60% elevated risk of cancer. The glucose level in the early phase may depend on the effectiveness of the molecular glucose-sensing apparatus. The transport of glucose into cancer cells, that normally requires a constant supply of high glucose, may be rate limited by polymorphisms that are critical for plasma glucose-sensing in general. Previous research has shown that some key proteins, e.g. GLUT 1 and GLUT 2, are involved as glucose transporters into cancer cells.