Transcription factor AP-1 in esophageal squamous cell carcinoma: alterations in activity and expression during human Papillomavirus infection

Histone 3 lysine 9 acetylation-specific reprogramming regulates esophageal squamous cell carcinoma progression and metastasis

Dysregulation of histone acetylation is widely implicated in tumorigenesis, yet its specific roles in the progression and metastasis of esophageal squamous cell carcinoma (ESCC) remain unclear. Here, we profiled the genome-wide landscapes of H3K9ac for paired adjacent normal (Nor), primary ESCC (EC) and metastatic lymph node (LNC) esophageal tissues from three ESCC patients. Compared to H3K27ac, we identified a distinct epigenetic reprogramming specific to H3K9ac in EC and LNC samples relative to Nor samples. This H3K9ac-related reprogramming contributed to the transcriptomic aberration of targeting genes, which were functionally associated with tumorigenesis and metastasis. Notably, genes with gained H3K9ac signals in both primary and metastatic lymph node samples (common-gained gene) were significantly enriched in oncogenes. Single-cell RNA-seq analysis further revealed that the corresponding top 15 common-gained genes preferred to be enriched in mesenchymal cells with high metastatic potential. Additionally, in vitro experiment demonstrated that the removal of H3K9ac from the common-gained gene MSI1 significantly downregulated its transcription, resulting in deficiencies in ESCC cell proliferation and migration. Together, our findings revealed the distinct characteristics of H3K9ac in esophageal squamous cell carcinogenesis and metastasis, and highlighted the potential therapeutic avenue for intervening ESCC through epigenetic modulation via H3K9ac.

JUND facilitates proliferation and angiogenesis of esophageal squamous cell carcinoma cell via MAPRE2 up-regulation

OBJECTIVE

Esophageal squamous cell carcinoma (ESCC) is a globally aggressive malignant tumor. This study aimed to investigate the mechanism of JUND in ESCC development via MAPRE2.

METHODS

ESCC cells (KYSE-450 and ECA109) were transfected with small interfering RNA (si)-JUND, si-MAPRE2, si-JUND, or pcDNA3.1-MAPRE2. JUND and MAPRE2 expression in ESCC cells was detected with quantitative real-time polymerase chain reaction and western blot. Cell counting kit-8 and 5-ethynyl-2'-deoxyuridine assays were used to determine ESCC cell proliferation. Dual-luciferase reporter gene and chromatin immunoprecipitation assays were performed to assess binding between JUND and MAPRE2. Human umbilical vein endothelial cells (HUVECs) were co-cultured with ESCC cell supernatants. Angiogenesis was assessed with an in vitro angiogenesis assay. Western blot was conducted to evaluate the expression of angiogenic proteins [vascular endothelial growth factor A (VEGFA), matrix metallopeptidase 9 (MMP-9), and angiopoietin-2 (ang2)].

RESULTS

The levels of expression of JUND and MAPRE2 were high in ESCC cells. Mechanistically, JUND bound to MAPRE2 promoter and increased MAPRE2 transcription. Downregulation of JUND or MAPRE2 inhibited KYSE-450 and ECA109 cell proliferation and reduced the levels of expression of VEGFA, MMP-9, and ang2 and tube formation in HUVECs co-cultured with ESCC cell supernatants. MAPRE2 upregulation counteracted the inhibitory effects of JUND silencing on cell proliferative and angiogenic capabilities in ESCC.

CONCLUSIONS

JUND promoted MAPRE2 transcription, thereby facilitating cell proliferative and angiogenic abilities in ESCC.

Insights into the role of complement regulatory proteins in HPV mediated cervical carcinogenesis

The persistent infection of high-risk Human papillomavirus (HR-HPV) induced cervical cancer remains a challenge in women worldwide including India. Recent advances in cancer research have paved the way for advanced cancer treatment modalities including immunotherapy by manipulating the function or number of cytotoxic T cells. It is well established that anaphylatoxins like C3a and C5a of complement system influence tumor growth by evading apoptosis leading to progression of cancer. The role of the complement system, particularly the complement regulatory proteins (CRPs) which are important determinants of immune response play a crucial role in carcinogenesis. In a tumor microenvironment (TME) assisted suppression of immune effector cells may be achieved through CRPs. However, recent advances in pharmacogenomics including drug designing and combination of these approaches have provided a holistic understanding of signaling pathways and their crosstalk, to regulate cellular communications.This review describes the role of complement system; particularly CRPs in HPV induced cervical carcinogenesis which may be used for designing anti- HPV or cervical cancer therapeutics.

Using network pharmacology approaches to identify treatment mechanisms for codonopsis in esophageal cancer

OBJECTIVE

We explored codonopsis mechanisms for the treatment of esophageal cancer using a network pharmacology approach.

MATERIALS AND METHODS

Using the Laboratory of Systems Pharmacology website, codonopsis compounds and targets were gathered. After identifying esophageal cancer target intersections from the GeneCards website, possible codonopsis targets for esophageal cancer were screened. A protein-protein interaction (PPI) network diagram of protein targets was then constructed using the STRING database. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG) pathway enrichment analyses were performed in R 3.6.0 software. A network diagram of "disease-drug-component-target-pathways" was also constructed using Cytoscape 3.7.1.

RESULTS

We screened 21 codonopsis compounds as possible esophageal cancer treatments and 31 drug-disease intersecting targets. GO enrichment analysis identified 778 biological process (BP) components, 15 cellular component (CC) components, and 50 molecular function (MF) components, and KEGG analyses identified 90 signaling pathways. Our analyses showed that p53 and PI3K-Akt signaling pathways (among others) were significant pathways in these processes.

CONCLUSIONS

Codonopsis may be used to treat esophageal cancer by multiple components, targets, and pathways.

Identification of a Putative Enhancer RNA for EGFR in Hyper-Accessible Regions in Esophageal Squamous Cell Carcinoma Cells by Analysis of Chromatin Accessibility Landscapes

Abnormal genetic and epigenetic modifications play a key role in esophageal cancer. By Assay for Transposase-Accessible Chromatin by sequencing (ATAC-seq), this study compared chromatin accessibility landscapes among two esophageal squamous cell carcinoma (ESCC) cell lines, KYSE-30 and KYSE-150, and a non-cancerous esophageal epithelial cell line, HET-1A. Data showed that hyper-accessible regions in ESCC cells contained genes related with cancer hallmarks, such as epidermal growth factor receptor (EGFR). Multi-omics analysis and digital-droplet PCR results demonstrated that several non-coding RNAs in EGFR upstream were upregulated in ESCC cells. Among them, one appeared to act as an enhancer RNA responsible for EGFR overexpression. Further motif analysis and pharmacological data suggested that AP-1 family transcription factors were able to bind the hyper-accessible regions and thus to regulate cancer cell proliferation and migration. This study discovered a putative enhancer RNA for EGFR gene and the reliance of ESCC on AP-1 transcription factor.

Human Papillomavirus Infection in Head and Neck Squamous Cell Carcinomas: Transcriptional Triggers and Changed Disease Patterns

Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous group of cancers. Collectively, HNSCC ranks sixth in incidence rate worldwide. Apart from classical risk factors like tobacco and alcohol, infection of human papillomavirus (HPV) is emerging as a discrete risk factor for HNSCC. HPV-positive HNSCC represent a distinct group of diseases that differ in their clinical presentation. These lesions are well-differentiated, occur at an early age, and have better prognosis. Epidemiological studies have demonstrated a specific increase in the proportions of the HPV-positive HNSCC. HPV-positive and HPV-negative HNSCC lesions display different disease progression and clinical response. For tumorigenic-transformation, HPV essentially requires a permissive cellular environment and host cell factors for induction of viral transcription. As the spectrum of host factors is independent of HPV infection at the time of viral entry, presumably entry of HPV only selects host cells that are permissive to establishment of HPV infection. Growing evidence suggest that HPV plays a more active role in a subset of HNSCC, where they are transcriptionally-active. A variety of factors provide a favorable environment for HPV to become transcriptionally-active. The most notable are the set of transcription factors that have direct binding sites on the viral genome. As HPV does not have its own transcription machinery, it is fully dependent on host transcription factors to complete the life cycle. Here, we review and evaluate the current evidence on level of a subset of host transcription factors that influence viral genome, directly or indirectly, in HNSCC. Since many of these transcription factors can independently promote carcinogenesis, the composition of HPV permissive transcription factors in a tumor can serve as a surrogate marker of a separate molecularly-distinct class of HNSCC lesions including those cases, where HPV could not get a chance to infect but may manifest better prognosis.

Human Papillomavirus Infection in Head and Neck Squamous Cell Carcinomas: Transcriptional Triggers and Changed Disease Patterns

Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous group of cancers. Collectively, HNSCC ranks sixth in incidence rate worldwide. Apart from classical risk factors like tobacco and alcohol, infection of human papillomavirus (HPV) is emerging as a discrete risk factor for HNSCC. HPV-positive HNSCC represent a distinct group of diseases that differ in their clinical presentation. These lesions are well-differentiated, occur at an early age, and have better prognosis. Epidemiological studies have demonstrated a specific increase in the proportions of the HPV-positive HNSCC. HPV-positive and HPV-negative HNSCC lesions display different disease progression and clinical response. For tumorigenic-transformation, HPV essentially requires a permissive cellular environment and host cell factors for induction of viral transcription. As the spectrum of host factors is independent of HPV infection at the time of viral entry, presumably entry of HPV only selects host cells that are permissive to establishment of HPV infection. Growing evidence suggest that HPV plays a more active role in a subset of HNSCC, where they are transcriptionally-active. A variety of factors provide a favorable environment for HPV to become transcriptionally-active. The most notable are the set of transcription factors that have direct binding sites on the viral genome. As HPV does not have its own transcription machinery, it is fully dependent on host transcription factors to complete the life cycle. Here, we review and evaluate the current evidence on level of a subset of host transcription factors that influence viral genome, directly or indirectly, in HNSCC. Since many of these transcription factors can independently promote carcinogenesis, the composition of HPV permissive transcription factors in a tumor can serve as a surrogate marker of a separate molecularly-distinct class of HNSCC lesions including those cases, where HPV could not get a chance to infect but may manifest better prognosis.

Expression and function of FRA1 protein in tumors

AP-1 is a dimeric complex that is composed of JUN, FOS, ATF and MAF protein families. FOS-related antigen 1 (FRA1) which encoded by FOSL1 gene, belongs to the FOS protein family, and mainly forms an AP-1 complex with the protein of the JUN family to exert an effect. Regulation of FRA1 occurs at levels of transcription and post-translational modification, and phosphorylation is the major post-translational modification. FRA1 is mainly regulated by the mitogen-activated protein kinases signaling pathway and is degraded by ubiquitin-independent proteasomes. FRA1 can affect biological functions, such as tumor proliferation, differentiation, invasion and apoptosis. Studies have demonstrated that FRA1 is abnormally expressed in many tumors and plays a relevant role, but the specific condition varies from the target organs. FRA1 is overexpressed in breast cancer, lung cancer, colorectal cancer, prostate cancer, nasopharyngeal cancer, thyroid cancer and other tumors. However, the expression of FRA1 is decreased in cervical cancer, and the expression of FRA1 in ovarian cancer and oral squamous cell carcinoma is still controversial. In this review, we present a detailed description of the regulatory factors and functions of FRA1, also, the expression of FRA1 in various tumors and its function in relative tumor.

Differential expression of Ets-1 in breast cancer among North Indian population

Breast cancer is a highly aggressive disease contributing to high mortality rate among females across the globe owing to wide geographical variations, change in lifestyle along with rapid tumor growth, drug resistance, and high metastasis rate. To understand the molecular and genetic basis of breast cancer progression; we studied the role of E26 transformation-specific-1 (Ets-1) transcription factor which is implicated to have a role in carcinogenesis like invasion, metastasis, angiogenesis, etc. Our findings revealed an overexpression of Ets-1 gene in 75 breast cancer tumors as compared with their normal adjacent tissues. The findings significantly established a co-relation between Ets-1 expression in breast cancer tissue with hormonal receptor profiles and ductal-lobular histological subtypes in Indian population. In addition, a differential expression pattern of Ets-1 was observed between high, moderate, and low grades of breast cancer patients. The present study demonstrates a crucial role of Ets-1 transcription factor which may serve as a potential biomarker for breast carcinogenesis.

Constitutive activation and overexpression of NF-κB/c-Rel in conjunction with p50 contribute to aggressive tongue tumorigenesis

Tongue squamous cell carcinoma (TSCC) is a most aggressive head and neck cancer often associated with a poor survival rate. Yet, it always shows better prognosis in presence of HPV16 infection. NF-κB plays a pivotal role in carcinogenesis and chemo-radio resistance of cancer but its role in tongue cancer is not yet explored. In this study, a total of hundred tongue tissue biopsies comprising precancer, cancer and adjacent normal controls including two tongue cancer cell lines (HPV^+/−ve) were employed to examine expression and transactivation of NF-κB proteins, their silencing by siRNA and invasion assays to understand their contributions in tongue carcinogenesis. An exclusive prevalence (28%) of HR-HPV type 16 was observed mainly in well differentiated tumors (78.5%). Increased DNA binding activity and differential expression of NF-κB proteins was observed with p50 and c-Rel being the two major DNA binding partners forming the functional NF-κB complex that increased as a function of severity of lesions in both HPV^+/−ve tumors but selective participation of p65 in HPV16^+ve TSCCs induced well differentiation of tumors resulting in better prognosis. siRNA treatment against c-Rel or Fra-2 led to upregulation of p27 but strong inhibition of c-Rel, c-Jun, c-myc, HPVE6/E7 and Fra-2 which is exclusively overexpressed in HPV^−ve aggressive tumors. In conclusion, selective participation of c-Rel with p50 that in cross-talk with AP-1/Fra-2 induced poor differentiation and aggressive tumorigenesis mainly in HPV^−ve smokers while HPV infection induced expression of p65 and p27 leading to well differentiation and better prognosis preferably in non-smoking TSCC patients.

Jagged-1 induced molecular alterations in HPV associated invasive squamous cell and adenocarcinoma of the human uterine cervix

The majority of cervical cancer (CC) cases are attributable to HPV infection. Altered Notch pathway signals and HPV are believed to modify clinicopathogenesis of CC, however, the involvement of each molecular player and its mechanism is still not known. Jagged-1 (JAG1) is one of the ligands that induce Notch pathway. The involvement of JAG1 in the modulation of a disease condition is not very clear. Hence, this study aims to study the role of JAG1 in HPV-16/18 associated different histological sub-types of CC, especially ADC. 40 non-neoplastic cervical tissues, 30 precancer and 118 tumor specimens (total 188 tissue biopsies) were studied for the expression of the JAG1 protein through immunohistochemistry, immunoblotting and for HPV infection. Two folds increase of cytoplasmic (Mean ± S.E, 3.67 ± 0.33; p = 0.0001) and nuclear (3.70 ± 0.38, p = 0.0001) JAG1 expression was identified in normal (N) vs precancer and three folds cytoplasmic (4.44 ± 0.17, p = 0.0001) and nuclear (4.64 ± 0.17; p = 0.0001) in N vs. ISCC. Total 85% of ADC patients were found to be infected with HPV, which were 100% infected with HPV-16. These findings suggest the complex synergistic interplay between JAG1 and HPV in regulating clinicopathological progression of CC through its deregulation.

A viral map of gastrointestinal cancers

Cancers of the gastrointestinal tract (GIT) are expected to account for approximately 20% of all cancers in 2017. Apart from their high incidence, GIT cancers show high mortality rates, placing these malignancies among the most prominent public health issues of our time. Cancers of the GIT are the result of a complex interplay between host genetic factors and environmental factors and frequently arise in the context of a continued active inflammatory response. Several tumor viruses are able to elicit such chronic inflammatory responses. In fact, several viruses have an impact on GIT tumor initiation and progression, as well as on patients' response to therapy and prognosis, through direct and indirect mechanisms. In this review, we have gathered information on different viruses' rates of infection, viral-driven specific carcinogenesis mechanisms and viral-related impact on the prognosis of cancers of the GIT (specifically in organs that have an interface with the environment - esophagus, stomach, intestines and anus). Overall, while some viral infections show a strong causal relation with specific gastrointestinal cancers, these represent a relatively small fraction of GIT malignancies. Other types of cancer, like Esophageal Squamous Cell Carcinoma, require further studies to confirm the carcinogenic role of some viral agents.

Overexpression of SRC-3 promotes esophageal squamous cell carcinoma aggressiveness by enhancing cell growth and invasiveness

Steroid receptor coactivator‐3 (SRC‐3), a transcriptional coactivator for nuclear receptors and other transcription factors, plays an important role in the genesis and progression of several cancers. However, studies investigated the role of SRC‐3 in esophageal squamous cell carcinomas (ESCCs) are limited, and the role of SRC‐3 in tumor progression remains unclear. We examined the expression of SRC‐3 in 8 ESCC cell lines and 302 human ESCC tissues by qPCR, Western blot, and immunohistochemistry. In addition, ESCC cell lines were subjected to proliferation and invasion assays, tumorigenicity assay, flow cytometry assay, qPCR, Western blot, and Chromatin Immunoprecipitation assay to investigate the role of SRC‐3 in cancer progression. SRC‐3 was overexpressed in 48% of cases and correlated with poor overall (P = 0.0076) and progression‐free (P = 0.0069) survival of surgically resected ESCC patient. Cox regression analysis revealed that SRC‐3 is an independent prognostic marker. Furthermore, we found that activation of insulin‐like growth factor (IGF)/AKT) was involved in the SRC‐3 on the cell growth and invasiveness in two ESCC cell lines, Eca109 and EC18 cells. SRC‐3 overexpression is clinically and functionally relevant to the progression of human ESCC, and might be a useful molecular target for ESCC prognosis and treatment.

Epigenetic silencing of HIC1 promotes epithelial-mesenchymal transition and drives progression in esophageal squamous cell carcinoma

Downregulation of the novel tumor suppressor gene HIC1 (hypermethylated in cancer 1) occurs frequently in various tumors where it causes tumor progression and metastasis. In this study, we investigated a role of HIC1 in esophageal squamous cell carcinoma (ESCC) and the underlying mechanisms. Downregulation of HIC1 occurred in approximately 70% of primary ESCCs at both mRNA and protein level where it was associated significantly with vascular invasion, advanced clinical stage, lymph node metastasis, and poor disease free survival (DFS). The promoter methylation analyses suggested that loss of HIC1 expression was mediated by epigenetic mechanisms. Functional studies established that ectopic re-expression of HIC1 in ESCC cells inhibited cell proliferation, clonogenicity, cell motility, tumor formation and epithelial-mesenchymal transition (EMT). Our results decipher the mechanism through which HIC1 deficiency induce ESCC cells to undergo EMT and promote tumor progression and metastasis through activation of EphA2 signaling pathway. Together, loss of the regulation of EphA2 pathway through HIC1 epigenetic silencing could be an important mechanism in the ESCC progression. We identify a novel pathway that linking HIC1 downregulation to EphA2-inducing EMT in ESCC cells and may shed light on the development of novel anti-tumor therapeutics.

Papillomavirus-Associated Tumor Formation Critically Depends on c-Fos Expression Induced by Viral Protein E2 and Bromodomain Protein Brd4

We investigated the mechanism of how the papillomavirus E2 transcription factor can activate promoters through activator protein (AP)1 binding sites. Using an unbiased approach with an inducible cell line expressing the viral transcription factor E2 and transcriptome analysis, we found that E2 induces the expression of the two AP1 components c-Fos and FosB in a Brd4-dependent manner. In vitro RNA interference confirmed that c-Fos is one of the AP1 members driving the expression of viral oncogenes E6/E7. Mutation analysis and in vivo RNA interference identified an essential role for c-Fos/AP1 and also for the bromodomain protein Brd4 for papillomavirus-induced tumorigenesis. Lastly, chromatin immunoprecipitation analysis demonstrated that E2 binds together with Brd4 to a canonical E2 binding site (E2BS) in the promoter of c-Fos, thus activating c-Fos expression. Thus, we identified a novel way how E2 activates the viral oncogene promoter and show that E2 may act as a viral oncogene by direct activation of c-Fos involved in skin tumorigenesis.

Human Papillomaviruses (HPV) are the etiological agents of cervical cancer and of skin cancer in individuals with the inherited disease epidermodysplasia verruciformis (EV). While the role of the viral oncogenes E6/E7 as drivers of tumorigenesis in cervical cancer has been firmly established, the contribution of the early viral genes in skin cancer is less clear. For EV-associated HPV8 and for the skin cancer model system using cottontail rabbit PV, an important role of the viral E2 protein in tumorigenesis was suggested earlier and regulation of cellular genes by E2 through different mechanisms was demonstrated. We show now that the viral E2 and cellular Brd4 act together to induce the cellular gene c-Fos, which as a member of the AP-1 complex, is involved in the regulation of cellular genes and the viral promoter driving the expression of viral oncogenes. As c-Fos has also been shown to be essential for skin cancer, E2 contributes to tumorigenesis via expression of E6/E7 as well as by increasing c-Fos.

Selective participation of c-Jun with Fra-2/c-Fos promotes aggressive tumor phenotypes and poor prognosis in tongue cancer

Tongue squamous cell carcinoma (TSCC) is most aggressive head and neck cancer often associated with HR-HPV infection. The role of AP-1 which is an essential regulator of HPV oncogene expression and tumorigenesis is not reported in tongue cancer. One hundred tongue tissue biopsies comprising precancer, cancer and adjacent controls including two tongue cancer cell lines were employed to study the role of HPV infection and AP-1 family proteins. An exclusive prevalence (28%) of HR-HPV type 16 was observed mainly in well differentiated tongue carcinomas (78.5%). A higher expression and DNA binding activity of AP-1 was observed in tongue tumors and cancer cell lines with c-Fos and Fra-2 as the major binding partners forming the functional AP-1 complex but c-Jun participated only in HPV negative and poorly differentiated carcinoma. Knocking down of Fra-2 responsible for aggressive tongue tumorigenesis led to significant reduction in c-Fos, c-Jun, MMP-9 and HPVE6/E7 expression but Fra-1 and p53 were upregulated. The binding and expression of c-Fos/Fra-2 increased as a function of severity of tongue lesions, yet selective participation of c-Jun appears to promote poor differentiation and aggressive tumorigenesis only in HPV negative cases while HPV infection leads to well differentiation and better prognosis preferably in nonsmokers.

The protective role of the -1306C>T functional polymorphism in matrix metalloproteinase-2 gene is associated with cervical cancer: implication of human papillomavirus infection

Cervical cancer is the major reproductive health problem among women caused by persistent infection of high-risk human papillomavirus (HR-HPV). Metalloproteinase-2 (MMP-2) is an endopeptidase highly expressed in cervical cancer; however, the genetic link between aberrant expression of MMP-2 and cervical carcinogenesis is not known. The genotypic distribution, expression pattern of MMP-2 and HPV infection, was analyzed in a total of 300 fresh surgically resected cervical tissue biopsies. The MMP-2 C1306T (rs243865) promoter polymorphism dominant model (CC v/s CT + CT + TT) revealed that the CC genotype had a 4.33-fold significant increased risk for development of cervical cancer (OR = 4.33; 95 % CI = 2.36-4.02, p = 0.0001) compared to those with variant genotypes (-1306 CT + TT). The C allele was associated with 3-fold significant increased risk (OR = 2.95; 95 % CI = 1.90-4.60, p = 0.0002) compared to T allele. Interestingly, a significant correlation was found between high expression of MMP-2 protein and CC genotype in cancer patients (p = 0.001) compared to normal controls (p = 0.012). Further analysis showed that the risk of cancer was extremely pronounced in HPV positive patients (OR = 9.33; 95 % CI = 2.88-30.20, p = 0.0001) compared to HPV negative ones, implicating the possible interaction between -1306CC genotype and HPV infection in increasing the cancer risk (p = 0.0001). The leads from the present study suggest the protective role of gene variant -1306C>T at the promoter region of the MMP-2 against HPV-mediated cervical cancer. These findings substantiate the functional role of MMP-2 C1306T polymorphism in a significant downregulation of MMP-2 protein in women with variant genotype (CT/TT) compared to the normal wild CC genotype.

Implication of high risk human papillomavirus HR-HPV infection in prostate cancer in Indian population--a pioneering case-control analysis

Prostate cancer is the second most common cancer with sexual history as a consistent risk factor. This is the pioneering study that evaluates the frequency of HPV infection in prostate cancer in India. Ninety five (95) histopathologically confirmed cancer and fifty five (55) BPH from Indian population were analyzed for HPV infection using a pair of consensus sequence primer followed by type specific PCRs for both high-risk and low-risk HPV types. The data demonstrate HPV infection in 41% of prostate tumor biopsies and 20% in BPH. Subsequent PCR- based HPV typing using type - specific primers revealed 32% were infected with HPV type 16 whereas 6% were found to be positive for HPV type 18, while in BPH controls only 5% of the BPH controls were infected with HPV 16 and this difference was highly significant (p = 0.0004). Significant proportion of HPV infected (74%) cases belonged to stage III and IV (p < 0.001) with a high Gleason score ≥8 (p = 0.003). The study represents for the first time the incidence of HPV infection in prostate cancer in Indian population and strengthens the hypothesis that HPV infection could be one of the co factor associated with progression of prostate cancer.

Clinical impact of de-regulated Notch-1 and Notch-3 in the development and progression of HPV-associated different histological subtypes of precancerous and cancerous lesions of human uterine cervix

BACKGROUND

Cervical cancer is the leading cause of cancer related deaths among women in India. Limited reports are available for Notch-1 and Notch-3 protein in cervical carcinoma, which play crucial role in cell proliferation, differentiation, and apoptosis.

METHODS

This study was designed to evaluate the role of Notch-1 and Notch-3 with context to HPV infection in cervical carcinoma. A total of 168 tissue biopsy samples comprising of tumor specimens (n = 98), precancer (n = 30) and non-neoplastic cervical tissues (n = 40) were screened for HPV infection by PCR and expression of Notch-1 and Notch-3 protein by Immunohistochemistry and Immunoblotting.

RESULTS

80% (24/30) were found to be positive for HPV in precancer and 86.7% (85/98) in cancer patients. Notch-1 expression of precancer and cancer cases was found to be significantly down-regulated with severity of disease in nuclear (3.43±0.29; 2.04±0.19, p = 0.0001, p = 0.0001) and cytoplasm (3.07±0.29; 2.29±0.17, p = 0.0001, p = 0.0001) obtained from different stages as compared to normal cervix tissue (5.40±0.19, 4.97±0.15; p<0.001; p<0.001). However, Notch-3 expression of above cases was significantly up-regulated with severity of disease and showed intense nuclear (4.17±0.39; 4.74±0.18, p = 0.0001, p = 0.0001) and cytoplasm (3.67±0.36; 4.48±0.18, p = 0.0001, p = 0.0001) of different stages as compared to normal cervix tissue (0.95±0.20, 0.70±0.20; p<0.001; p<0.001) respectively.

CONCLUSIONS

These findings suggest that Notch-1 and Notch-3 may play an important role with synergistic effect of HPV in regulating development and proliferation of cervical cancer through the deregulation of Notch signalling. This study also shows the clinical utility of both proteins which may be used as predictable biomarkers in diagnosing different histological sub-types of HPV associated cervical cancer. Nevertheless, abnormal activation of this pathway may provide legitimate targets for cervical cancer therapy.

Role of human papillomaviruses in esophageal carcinoma: an updated systematic review from 1982 to 2013

ABSTRACT: 

Tobacco, alcohol and betel quid are known etiological agents of esophageal squamous cell carcinoma (ESCC). A meta-analysis in 2012 and a literature update (1982–August 2013) identified 159 studies with a total of 11,310 ESCCs tested for the presence of human papillomaviruses (HPVs). HPV DNA was present in 30.3% of fESCCs, with substantial geographic differences. A recent meta-analysis of 21 case–control studies investigating the HPV–ESCC association showed that HPVs increase the risk of ESCC at least threefold. Vaccine-preventable HPV-16 and HPV-18 are the most commonly identified HPV types in ESCC in both low- and high-incidence settings. HPVs should now be seriously considered as etiological agents for at least a subset of ESCC, and more studies are needed to provide conclusive evidence that HPVs cause ESCC.

The role of glycogen synthase kinase 3-β in immunity and cell cycle: implications in esophageal cancer

Esophageal cancer (EC) is one of the most aggressive gastrointestinal malignancies, possessing an insidious onset and a poor prognosis. Numerous transcription factors and inflammatory mediators have been reported to play a pivotal role in the initiation and progression of this cancer. However, the specifics of the signaling network responsible for said factors, especially which elements are the critical regulators, are still being elucidated. Glycogen synthesis kinases 3 (GSK3)β was originally regarded as a kinase regulating glucose metabolism. Accumulating evidence demonstrated that it also played an essential role in a variety of cellular processes including proliferation, differentiation, inflammation, motility, and survival by regulating various transcription factors such as c-Jun, AP-1, β-catenin, CREB, and NF-κB. Aberrant regulation of GSK3β has been shown to promote cell growth in some cancers, while suppressing it in others, and thus may play an important role in the development of EC. This review will discuss our current understanding of GSK3β signaling, and its control of the expression and activation of various transcription factors that mediate the inflammatory response. We will also explore some of the known mediators of EC progression, and based on current literature, elucidate the potential roles and implications of GSK3 in this disease.

Downregulation of tumor suppressor gene PML in uterine cervical carcinogenesis: impact of human papillomavirus infection (HPV)

OBJECTIVES

Cervical cancer is a leading gynecological cancer in Indian women and is caused due to infection with high risk human pappilloma virus (HR-HPV) 16 and 18. It has been well documented that PML (promyelocytic leukemia) enhances viral infectivity and plays a crucial role in antiviral response mechanisms. The aim of the present study was to evaluate the role of PML gene with context to HPV infection in cervical carcinogenesis.

METHODS

The expression pattern of PML was analyzed by western blotting and immunohistochemistry in a total of 170 fresh surgically resected cervical tissue specimens comprising precancer (n=12), cancer (n=118) and normal controls (n=40) recruited from PGIMER, Chandigarh, India. HPV status was analyzed by L1 consensus PCR followed by type specific PCR for HR-HPV types 16 and 18 and low risk types 6 and 11.

RESULTS

A significant downregulation of PML protein was observed in the majority of cervical cancer and precancer cases 68% (89/130) compared to normal controls. The loss of expression pattern of PML gene was significantly increased with severity of disease both clinically and pathologically (p<0.001). HPV infection was detected in the majority of cancer cases 96% (113/118) and in 83% (10/12) of precancer lesions whereas no infection could be detected in normal controls. Interestingly, all the 68% (89/130) cervical cancer cases that showed downregulation of PML were HPV infected (p=0.0001).

CONCLUSION

Taken together, these observations suggest that the downregulation of PML gene and its synergism with HPV infection may play an important role and may serve as a new marker for early diagnosis and therapeutic intervention for cervical carcinogenesis.

Role of human papillomaviruses in esophageal squamous cell carcinoma

Esophageal cancer (EC) is responsible for almost half a million deaths worldwide annually and has a multifactorial etiology, which may account for its geographical variation in incidence. In the last 30 years the potential of human papillomaviruses (HPV) as oncogenes or co-factors in the tumorigenic process of esophageal squamous cell carcinoma (ESCC) has been widely studied. While the etiology of HPV in cervical and certain other anogenital and aerodigestive cancers has been established, results regarding its role in EC have been largely inconclusive. A causal association can be evaluated only with a case-control study, where normal controls are compared to ESCC cases for the presence of HPV. We reviewed all studies investigating ESCC tissue for HPV DNA and identified 139 that met our inclusion criteria, of which only 22 were case-control studies. Our results support previous findings of higher levels of HPV detection in high-risk ESCC regions than in areas of low risk. In addition, we confirm that the role of HPV in ESCC remains unclear, despite an accumulation of studies on the subject. The variations in investigative technique, study design and sample types tested may account for the lack of consistency in results. There is a need for a meta-analysis of all case-control studies to date, and for large, well-designed case-control studies with adequate power to investigate the association. The potential benefits of prophylactic HPV vaccines could be evaluated if HPV is identified as an etiological factor in EC, highlighting the need for further research in this area.

Geographic origin is a significant determinant of human papillomavirus prevalence in oesophageal squamous cell carcinoma: systematic review and meta-analysis

BACKGROUND

Since the first reports in 1982 suggesting an aetiological role for human papillomavirus (HPV) in a subset of oesophageal squamous cell carcinomas (ESCC), the literature reporting HPV detection in ESCC has expanded rapidly. However no formal meta-analysis of this literature has been published yet. The objective of this study was to perform a systematic review and formal meta-analysis of the literature reporting HPV detection in ESCC.

METHODS

MEDLINE and Current Contents were searched through March 2012. The effect size was calculated as event rates and their 95% confidence interval (95% CI), with homogeneity testing using Cochran's Q and I² statistics. Meta-regression was used to test the impact of study-level covariates (HPV detection method, geographic origin of study) on effect size, and potential publication bias was estimated using funnel plot symmetry (Begg and Mazumdar rank correlation, Egger's regression, and Duval and Tweedie's trim and fill method).

RESULTS

Of the 1177 abstracts found, 152 studies were determined to be eligible for this meta-analysis. These 152 studies covered a total of 10,234 ESCC cases, analysed by different HPV detection methods in different geographic regions. Of these 10,234 cases, 3135 (30.6%) tested HPV-positive, translating to an effect size of 0.372 (95% CI 0.360-0.384; fixed effects model) and 0.290 (95% CI 0.251-0.31; random effects model). When stratified by HPV detection technique, there was a significant heterogeneity between the studies, but importantly, the between-strata summary comparison was not significant (random effects model; p = 0.440). In contrast, there was significant heterogeneity between the studies from the different geographic regions. In the maximum likelihood meta-regression, HPV detection method was not a significant study-level covariate, in contrast to the geographic origin of the study, which had a significant impact (p = 0.00005) on the summary effect size estimates. No evidence for significant publication bias was found in funnel plot symmetry testing. In the sensitivity analysis, all meta-analytic results appeared robust to all (n = 151) one-by-one study removals.

CONCLUSIONS

These meta-analysis results indicate that the reported wide variability in HPV detection rates in ESCC is not due to the HPV detection techniques, but is explained by the geographic origin of the study. These data substantiate the recently elaborated concept that ESCC might have a different aetiology in low-incidence and high-incidence geographic regions, HPV playing an important role only in the latter.

HPV16E6-dependent c-fos expression contributes to AP-1 complex formation in SiHa cells

To date, the major role of HPV16E6 in cancer has been considered to be its ability to inhibit the p53 tumor-suppressor protein, thereby thwarting p53-mediated cytotoxic responses to cellular stress signals. Here, we show that HPV16E6-dependent c-fos oncogenic protein expression contributes to AP-1 complex formation under oxidative stress in SiHa cells (HPV16-positive squamous cell carcinoma of the cervix). In addition, we examined the role of HPV16E6 in TGF-α-induced c-fos expression and found that the c-fos protein expression induced by TGF-α is HPV16E6 dependent. Thus, our results provide the first evidence that HPV16E6 contributes to AP-1 complex formation after both ligand-dependent and independent EGFR activation, suggesting a new therapeutic approach to the treatment of HPV-associated tumors.

Association of cyclin D1 gene polymorphisms with risk of esophageal squamous cell carcinoma in Kashmir Valley: a high risk area

Investigation of potential association of SNPs (G870A, rs9344; G1722C, rs678653) of cyclin D1 gene (CCND1) with susceptibility to esophageal squamous cell carcinoma (ESCC) in Kashmir valley (India). The study included 302 subjects comprising 151 ESCC cases and 151 controls. PCR-RFLP and direct sequencing were employed for genotyping. The G870A polymorphism, the individuals carrying GA + AA genotype was having 2.80-fold increased risk for development of ESCC (OR 2.8, 95% CI = 1.77-4.4; P = 0.0001) compared to GG genotype. Further a significantly higher risk was observed in individuals who consume >3 cups per day of salted tea (OR = 5.1; 95% CI = 1.6-16.7; P = 0.0016) and had smoking habits (OR = 6.3; 95% CI = 2.9-13.9; P = 0.0005). We also demonstrate for the first time in CCND1 1722 locus, the CC genotype was strongly associated with increased risk of developing ESCC (OR = 2.58; 95% CI = 1.61-4.15; P = 0.0001). In addition, the frequency of polymorphic C allele was also found to be higher in cases (OR = 1.92; 95% CI = 1.37-2.69; P = 0.0002). There appears to be an influence of CCND1 G870A/G1772C genotypes on genetic susceptibility to ESCC.