Prior human polyomavirus and papillomavirus infection and incident lung cancer: a nested case-control study

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.

High-Risk Human Papillomavirus Infection in Lung Cancer: Mechanisms and Perspectives

Lung cancer is a very prevalent and heterogeneous group of malignancies, and most of them are etiologically associated with tobacco smoking. However, viral infections have been detected in lung carcinomas, with high-risk human papillomaviruses (HR-HPVs) being among them. The role of HR-HPVs in lung cancer has been considered to be controversial. This issue is due to the highly variable presence of this virus in lung carcinomas worldwide, and the low viral load frequently that is detected. In this review, we address the epidemiological and mechanistic findings regarding the role of HR-HPVs in lung cancer. Some mechanisms of HR-HPV-mediated lung carcinogenesis have been proposed, including (i) HPV works as an independent carcinogen in non-smoker subjects; (ii) HPV cooperates with carcinogenic compounds present in tobacco smoke; (iii) HPV promotes initial alterations being after cleared by the immune system through a "hit and run" mechanism. Additional research is warranted to clarify the role of HPV in lung cancer.

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.

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 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.

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.

Difference of lower airway microbiome in bilateral protected specimen brush between lung cancer patients with unilateral lobar masses and control subjects

The functional role of respiratory microbiota has attracted an accumulating attention recently. However, the role of respiratory microbiome in lung carcinogenesis is mostly unknown. Our study aimed to characterize and compare bilateral lower airway microbiome of lung cancer patients with unilateral lobar masses and control subjects. Protected bronchial specimen brushing samples were collected from 24 lung cancer patients with unilateral lobar masses (paired samples from cancerous site and the contralateral noncancerous site) and 18 healthy controls undergoing bronchoscopies and further analyzed by 16S rRNA amplicon sequencing. As results, significant decreases in microbial diversity were observed in patients with lung cancer in comparison to the controls, alpha diversity steadily declined from healthy site to noncancerous to cancerous site. Genus Streptococcus was significantly more abundant in cancer cases than the controls, while Staphylococcus was more abundant in the controls. The area under the curve of genus Streptococcus used to predict lung cancer was 0.693 (sensitivity = 87.5%, specificity = 55.6%). The abundance of genus Streptococcus and Neisseria displayed an increasing trend whereas Staphylococcus and Dialister gradually declined from healthy to noncancerous to cancerous site. Collectively, lung cancer-associated microbiota profile is distinct from that found in healthy controls, and the altered cancer-associated microbiota is not restricted to tumor tissue. The genus Streptococcus was abundant in lung cancer patients and exhibited moderate classification potential. The gradual microbiota profile shift from healthy site to noncancerous to paired cancerous site suggested a change of the microenvironment associated with the development of lung cancer.

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.

Survey of KI, WU, MW, and STL Polyomavirus in Cancerous and Non-Cancerous Lung Tissues

BACKGROUND/AIMS

The pathogenesis of the human polyomavirus (PyV) KI, WU, MW, and STL has not been elucidated yet. Respiratory transmission is suggested, but the site of the replication, tissue, and cell tropism is not clarified. KIPyV and WUPyV DNA and/or antigen were detected in normal lung tissues previously by others. In fact, a KIPyV DNA sequence was found in lung cancer samples. Up to date, there is no publication about the DNA prevalence of MWPyV and STLPyV neither in normal nor in cancerous lung tissues. The aim of the present study was to examine the DNA prevalence of these polyomaviruses in cancerous and non-cancerous lung tissue samples, in order to study the possible site for viral replication and/or persistence, and the potential association of these viruses with lung carcinogenesis as well.

METHODS

100 cancerous and 47 non-cancerous, formalin-fixed paraffin-embedded lung tissue samples were studied for KIPyV, WUPyV, MWPyV, and STLPyV by real-time PCR.

RESULTS AND CONCLUSION

Neither of the viruses was found in samples from small-cell, non-small-cell (adenocarcinoma, squamous-cell carcinoma and large-cell neuroendocrine lung cancer), mixed-type and non-differentiated lung carcinoma, and non-cancerous lung tissues (from patients with pneumonia, emphysema and fibrosis).

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.

Risk factors for lung cancer worldwide

Lung cancer is the most frequent malignant neoplasm in most countries, and the main cancer-related cause of mortality worldwide in both sexes combined.The geographic and temporal patterns of lung cancer incidence, as well as lung cancer mortality, on a population level are chiefly determined by tobacco consumption, the main aetiological factor in lung carcinogenesis.Other factors such as genetic susceptibility, poor diet, occupational exposures and air pollution may act independently or in concert with tobacco smoking in shaping the descriptive epidemiology of lung cancer. Moreover, novel approaches in the classification of lung cancer based on molecular techniques have started to bring new insights to its aetiology, in particular among nonsmokers. Despite the success in delineation of tobacco smoking as the major risk factor for lung cancer, this highly preventable disease remains among the most common and most lethal cancers globally.Future preventive efforts and research need to focus on non-cigarette tobacco smoking products, as well as better understanding of risk factors underlying lung carcinogenesis in never-smokers.

Absence of an association of human polyomavirus and papillomavirus infection with lung cancer in China: a nested case-control study

Background

Studies of human polyomavirus (HPyV) infection and lung cancer are limited and those regarding the association of human papillomavirus (HPV) infection and lung cancer have produced inconsistent results.

Methods

We conducted a nested case–control study to assess the association between incident lung cancer of various histologies and evidence of prior infection with HPyVs and HPVs. We selected serum from 183 cases and 217 frequency matched controls from the Yunnan Tin Miner’s Cohort study, which was designed to identify biomarkers for early detection of lung cancer. Using multiplex liquid bead microarray (LBMA) antibody assays, we tested for antibodies to the VP1 structural protein and small T antigen (ST-Ag) of Merkel cell, KI, and WU HPyVs. We also tested for antibodies against HPV L1 structural proteins (high-risk types 16, 18, 31, 33, 52, and 58 and low-risk types 6 and 11) and E6 and E7 oncoproteins (high risk types 16 and 18). Measures of antibody reactivity were log transformed and analyzed using logistic regression.

Results

We found no association between KIV, WUV, and MCV antibody levels and incident lung cancer (P-corrected for multiple comparisons >0.10 for all trend tests). We also found no association with HPV-16, 18, 31, 33, 52, and 58 seropositivity (P-corrected for multiple comparisons >0.05 for all).

Conclusions

Future studies of infectious etiologies of lung cancer should look beyond HPyVs and HPVs as candidate infectious agents.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2381-3) contains supplementary material, which is available to authorized users.