Early upregulation of cyclooxygenase-2 in human papillomavirus type 16 and telomerase-induced immortalization of human esophageal epithelial cells

Immune Cell Metabolism in Tumor Microenvironment

Tumor microenvironment (TME) is composed of tumor cells, immune cells, cytokines, extracellular matrix, etc. The immune system and the metabolisms of glucose, lipids, amino acids, and nucleotides are integrated in the tumorigenesis and development. Cancer cells and immune cells show metabolic reprogramming in the TME, which intimately links immune cell functions and edits tumor immunology. Recent findings in immune cell metabolism hold the promising possibilities toward clinical therapeutics for treating cancer. This chapter introduces the updated understandings of metabolic reprogramming of immune cells in the TME and suggests new directions in manipulation of immune responses for cancer diagnosis and therapy.

Methylation‑associated silencing of miR‑128 promotes the development of esophageal cancer by targeting COX‑2 in areas with a high incidence of esophageal cancer

Esophageal cancer is one of the most common cancer types in the world, with a widely varying incidence between different regions. Zinc deficiency (ZD) is very common in high‑risk areas for esophageal cancer. Dietary ZD is reported to be associated with esophageal squamous cell carcinoma (ESCC). In the current study, the effects of ZD on tumorigenesis and expression of inflammatory factors were investigated in mice. It was identified that a ZD diet advanced ESCC and increased the expression of cyclooxygenase‑2 (COX‑2) prior to the occurrence of ESCC in mice. ZD significantly enhanced DNA methyltransferase (DNMT) activity and increased the expression of DNMT1 and DNMT3B. Furthermore, the expression of miR‑128 was downregulated by methylation, and COX‑2, a direct target of miR‑128, was upregulated with the reduction in miR‑128. Upregulation of miR‑128 inhibited the cell cycle, proliferation and metastasis, and the expression of COX‑2, cyclin D1 and retinoblastoma protein (Rb). Furthermore, the relative expression level of miR‑128 was negatively associated with COX‑2 in ESCC tissues. Collectively, these findings indicate that methylation‑associated silencing of miR‑128 promotes the development of esophageal cancer through upregulation of the expression of cyclin D1 and Rb by targeting COX‑2 in ZD regions with a high incidence of esophageal cancer.

Cyclooxygenase-2 Expression Is a Predictive Marker for Late Recurrence in Colorectal Cancer

Introduction

Cyclooxygenase-2 (COX-2) expression is elevated in colorectal cancer (CRC). However, data about the relation between COX-2 expression and the impact on the biologic behavior of recurrent disease are inconclusive as yet. The aim of this study is to investigate the relationship between the status of COX-2 expression in the primary CRC and the characteristics of recurrence after curative resection of stage I to III CRC.

Materials and Methods

Ninety-eight patients with recurrence in 376 CRC patients, who underwent curative surgery between January 1991 and August 2001, were retrospectively assessed. Immunohistochemical staining, performed for the presence of COX-2 on tissue microarrays, was analyzed.

Results

Forty-six patients showed elevated COX-2 expression, and 52 patients did not. The mean time to recurrence was significantly longer in the positive group than in the negative group (34.1 months ± 30.0 versus 21.9 months ± 17.4; P = 0.019). Positive COX-2 expression was correlated with late recurrence (>3 years after surgery) [43.5% versus 13.5%; P = 0.001]. In multivariate analysis, COX-2 expression was an independent factor associated with late recurrence (OR 4.656; 95% CI, 1.696 to 12.779; P = 0.003). Recurrence pattern and postrecurrence survival were not different between the two groups.

Conclusions

Elevated COX-2 expression in itself is not a prognostic factor, but COX-2 expression in tumor tissue may be an independent predictive marker of late recurrence for patients with stage I to III CRC.

HPV16 E7 increases COX-2 expression and promotes the proliferation of breast cancer

Breast cancer remains the leading cause of mortality worldwide. Human papilloma virus 16 (HPV16) may serve a function in the pathogenesis and development of breast cancer. However, the detection rate of HPV16 in breast carcinoma may vary by region. In the present study, the expression of HPV16 E7 in paraffin-embedded tissues from patients with breast cancer from North China was detected. Additionally, the molecular mechanisms underlying the function of HPV16 E7 in the proliferation of breast cancer cells were examined. The results demonstrated that the DNA of HPV16 E7 was detected in 30.5% of the samples, and that HPV16 E7 promoted the proliferation of breast cancer cells in vitro and in vivo. Additionally, HPV16 E7-mediated proliferation of breast cancer cells was suppressed in response to treatment with cyclooxygenase-2 (COX-2)-specific small interfering RNA and celecoxib. The results of the present study revealed that HPV16 E7 may promote the proliferation of breast cancer cells by upregulating COX-2, suggesting that COX-2 may be a potential therapeutic target for HPV16 E7-mediated progression of breast cancer.

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.

Fascin phosphorylation sites combine to regulate esophageal squamous cancer cell behavior

Filopodia are dynamic membrane extensions generated by F-actin bundling and are involved in cancer cell migration, invasion and metastasis. Fascin is the crucial actin-bundling protein in filopodia, with phosphorylation at fascin serine 39 being well characterized to regulate fascin-mediated actin bundling in filopodia. However, increasing evidence indicates that fascin is phosphorylated at a number of sites. Whether phosphorylation at other sites also regulates fascin function is unknown. In this study, we show that four potential phosphorylation sites in fascin, specifically tyrosine 23, serine 38, serine 39 and serine 274, regulate cell behavior and filopodia formation in esophageal squamous cancer cells. Expression of non-phosphorylatable mutations at each of the four sites promoted anchorage-independent growth, cell motility and filopodia formation, whereas phosphomimetic mutations at each of these sites inhibited these cell behaviors, implying that fascin function in esophageal squamous cancer is regulated by fascin phosphorylation at multiple sites. Furthermore, phosphorylation at S38 and S39 cooperatively regulated cell behavior and filopodia formation, with dual dephosphorylation at both S38 and S39 residues maximally enhancing cell proliferation, migration and filopodia formation, and phosphorylation at any of the two phosphorylatable sites resulting in reduced enhancement. Taken together, our results reveal that phosphorylation at fascin amino acids Y23, S38, S39 and S274, in combination, downregulates the extent of anchorage-independent growth, cell migration and filopodia formation in esophageal squamous cancer cells.

Biological characterization of three immortalized esophageal epithelial cell lines

The key molecular events that contribute to tumorigenesis are incompletely understood. The aim of the present study was to characterize and compare the biological phenotypes of three human telomerase reverse transcriptase (hTERT) and/or human papillomavirus 16 E6 and E7‑immortalized esophageal epithelial cell lines, NE2‑hTERT (NE2), NE3‑E6E7‑hTERT (NE3) and NEcA6‑E6E7‑hTERT (NEcA6). The present study used soft‑agar colony formation assays, tumorigenicity assays in nude mice, and cell proliferation, adhesion and migration assays to identify the biological characteristics of NE2, NE3 and NEcA6 cells. NE2 and NE3 cells exhibited characteristics of benign cells, such as the inability to grow in soft agar or form tumors in nude mice. By contrast, NEcA6 cells had undergone transformation, as demonstrated by the ability to grow in soft agar and form tumors in nude mice. In addition, NEcA6 cells exhibited increased migration and adhesion capabilities when compared with NE2 and NE3 cells. In order to identify mechanism(s) that may contribute to the altered biological phenotypes exhibited by these cells, the expression of three proteins involved in modulating cell migration [fascin, ezrin/radixin/moesin family proteins and phosphorylated‑focal adhesion kinase (Tyr 397)], as well as the expression status and subcellular localization of three key focal adhesions components (paxillin, talin and kindlin‑2) were examined. Paxillin, talin and kindlin‑2 were localized to adhesive sites that connect F‑actin with the extracellular matrix in transformed NEcA6 cells, but were distributed in a diffuse manner in NE2 and NE3 cells. Knockdown of kindlin‑2 in NE3 and NEcA6 cells decreased cell adhesion, however, NEcA6 cells demonstrated a greater sensitivity to knockdown of kindlin‑2. No significant differences were observed in the protein expression levels of fascin, exrin/radixin/moesin and p‑FAK in the three cell lines. In conclusion, these results demonstrate that these three focal adhesion components, particularly kindlin‑2, may contribute to the carcinogenesis of esophageal squamous cells.

The challenges for cancer chemoprevention

The incidence of cancer is rising in parallel with an ageing populous thus increasing the strain on both treatment options and budgets for healthcare providers worldwide. New cancer therapies are being developed but at what cost? The new treatments are expensive and poor survival rates still exist for some cancers. What is needed now is to prevent or at least limit the disease occurring in the first place. This review evaluates the current situation and the progress in upcoming strategies as well as suggesting some areas for further research within the increasingly important field of cancer chemoprevention. The key principles of cancer chemoprevention are discussed and areas for improvement highlighted. Despite significant progress, chemoprevention has not been widely adopted. Cancer chemoprevention has many challenges to face but this only emphasises the size of the task. These hurdles include a lack of awareness of the benefits, a lack of interest and a lack of investment in taking prevention forward. Despite the huge potential importance of cancer prevention and clinical success stories such as the well-publicised HPV vaccine, the challenges remain significant. With cancer and its treatment being a global issue, the opportunities offered by chemoprevention must be re-evaluated and uptake of chemoprevention actively encouraged. If chemoprevention is to be adopted successfully, a holistic approach is required. This approach will involve multidisciplinary teams of healthcare providers and scientists with the big challenge particularly for medicinal chemists being to design and synthesise the ideal chemopreventative agent.

Expression of human papillomavirus is correlated with Ki-67 and COX-2 expressions in keratocystic odontogenic tumor

The aim of the current study was to investigate the presence of human papillomavirus (HPV) and evaluate its association with Ki-67 and cyclooxygenase-2 (COX-2) expressions in keratocystic odontogenic tumor (KCOT). Nineteen cases were included in the present study. Conventional PCR method and immunohistochemical analysis were performed for the detection of HPV-DNA and HPV-L1 capsid protein. Moreover, the expressions of Ki-67 and COX-2 proteins were analyzed immunohistochemically. HPV-DNA was detected in 36.8% (7/19) of tumor samples, whilst HPV-L1 protein was identified in 68.4% (13/19) of them. The Kappa coefficient statistical test showed a moderate agreement (κ 0.424) between PCR and IHC assays for HPV detection. Expression of HPV-DNA was positively correlated with Ki-67 and COX-2 expressions (p < 0.05), whereas HPV-L1 positive staining was positively correlated with COX-2 (p < 0.05) and highly associated with those of Ki-67 (p < 0.01). There was no significant correlation between the presence of HPV and the recurrence of the studied lesions. The results of the current study showed that active HPV infection was present in the odontogenic epithelium of KCOT, and it was associated with increased proliferation rate and COX-2 expression. These findings suggest that HPV may have a role in the pathogenesis and aggressiveness of KCOT. Based on these conclusions, we recommend further investigations of HPV vaccine or antiviral therapy and COX-2 inhibitors as nonsurgical options in the prevention and management of KCOT.

Reduction in cancer risk by selective and nonselective cyclooxygenase-2 (COX-2) inhibitors

We conducted a series of epidemiologic studies to evaluate the chemopreventive effects of aspirin, ibuprofen, and selective cyxlooxygenase-2 (COX-2) inhibitors (coxibs) against cancers of the breast, colon, prostate, and lung. Composite results across all four cancer sites revealed that regular intake of 325 mg aspirin, 200 mg ibuprofen, or standard dosages of coxibs (200 mg celecoxib or 25 mg rofecoxib) produced risk reductions of 49%, 59%, and 64%, respectively. Use of coxibs for at least 2 years was associated with risk reductions of 71%, 70%, 55%, and 60% for breast cancer, colon cancer, prostate cancer and lung cancer, respectively. Effects of ibuprofen were similar to selective coxibs, and slightly stronger than aspirin. These observed effects are consistent with the relative COX-2 selectivity of ibuprofen, coxibs, and aspirin. Acetaminophen, an analgesic without COX-2 activity, had no effect. Overexpression of COX-2 and increased prostaglandin biosynthesis correlates with carcinogenesis and metastasis at most anatomic sites. These results indicate that regular intake of nonselective or selective COX-2 inhibiting agents protects against the development of major forms of cancer.

Cyclooxygenase-2 in oncogenesis

Compelling experimental and clinical evidence supports the notion that cyclooxygenase-2, the inducible isoform of cyclooxygenase, plays a crucial role in oncogenesis. Clinical and epidemiological data indicate that aberrant regulation of cyclooxygenase-2 in certain solid tumors and hematological malignancies is associated with adverse clinical outcome. Moreover, findings extrapolated from experimental studies in cultured tumor cells and animal tumor models indicate that cyclooxygenase-2 critically influences all stages of tumor development from tumor initiation to tumor progression. Cyclooxygenase-2 elicits cell-autonomous effects on tumor cells resulting in stimulation of growth, increased cell survival, enhanced tumor cell invasiveness, stimulation of neovascularization, and tumor evasion from the host immune system. Additionally, the oncogenic effects of cyclooxygenase-2 stem from its unique ability to impact tumor cell surroundings and create a proinflammatory environment conducive for tumor development, growth and progression. The initial enthusiasm generated by the availability of cyclooxygenase-2 selective inhibitors for cancer prevention and therapy has been lessened by the severe cardiovascular adverse side effects associated with their long-term use, as well as by the mixed results of recent clinical trials evaluating the efficacy of cyclooxygenase-2 inhibitors in adjuvant chemotherapy. Therefore, our ability to efficiently target the oncogenic effects of cyclooxygenase-2 for therapeutic and preventive purposes strictly depends on a better understanding of the spatial and temporal aspects of its activation in tumor cells along with a clearer elucidation of the signaling networks whereby cyclooxygenase-2 affects tumor cells and their interactions with the tumor microenvironment. This knowledge has the potential of leading to the identification of novel cyclooxygenase-2-dependent molecular and signaling networks that can be exploited to improve cancer prevention and therapy.

The HPV-16 E5 protein represses expression of stress pathway genes XBP-1 and COX-2 in genital keratinocytes

The HPV-16 E5 protein resides in membranes of the endoplasmic reticulum (ER) and modulates cell growth and viral replication. In order to help define its biological activities, we analyzed E5-induced changes in human keratinocyte gene expression. Our studies identified the downregulation of spliced XBP-1 transcripts, a key player in the ER stress response, as a biochemical marker of E5 expression. IRE1alpha, the endoribonuclease responsible for XBP-1 RNA splicing, was also downregulated. Furthermore, cDNA microarray analysis revealed the repression of COX-2, another member of the ER stress pathway. In contrast, these genes were not altered either by the low-risk HPV-6b E5, or a C-terminal HPV-16 E5 mutant, in which the histidine and alanine residues (conserved in high-risk HPVs) were replaced with tyrosine and isoleucine (conserved in low-risk HPVs). HPV-16 E5 was also able to lower COX-2 mRNA levels in cells co-expressing E6/E7, suggesting that it might exert similar activity during viral replication. Interestingly, the E6/E7 genes were independently able to lower COX-2 transcripts compared to vector cells, indicating that multiple pathways of COX-2 repression exist. COX-2 downregulation by E5 could be overcome by thapsigargin or tunicamycin treatments, which initiate ER stress via calcium fluxes and abnormal protein glycosylation respectively, making it unlikely that E5 specifically tempers these pathways. Overall, our data indicate that E5 represses the cellular ER stress response and suggest a potential role for E5 during productive HPV infection.

The relationship between HPV16 and expression of cyclooxygenase-2, P53 and their prognostic roles in esophageal squamous cell carcinoma

OBJECTIVES

This study aimed to investigate the relationship between human papillomavirus type 16 (HPV16) and expression of cyclooxygenase-2 (COX-2), P53 in esophageal squamous cell carcinoma (ESCC), which has not yet been elucidated.

METHODS

HPV16 was detected by amplifying the HPV16 E6 gene by the PCR method, and the expression of COX-2, P53 protein in 69 ESCCs and 32 normal esophageal mucosa (NEM) from Shaanxi Province was examined by the streptavidin-peroxidase method. Estimation of overall survival by HPV16, COX-2, and P53 was calculated with the Kaplan-Meier method and analyzed with the log-rank test.

RESULTS

The infection rate of HPV16 in ESCCs (35 of 69, 50.7%) was significantly higher than that in NEMs (two of 32, 6.25%) (P<0.01). The expression rate of COX-2 in ESCCs (44 of 69, 63.8%) was higher than that in NEMs (two of 32, 6.25%) (P<0.01). The expression intensity of COX-2 expression had statistical difference in histological grade (R = 0.4453, P = 0.0019), tumor stage (R = 0.438, P = 0.000), and metastasis (R = 0.417, P = 0.002). P53 expression rate was 49.3% (34 of 69) in ESCC and 18.8% (six of 32) in NEMs. The expression rate of P53 proteins in ESCC was statistically higher than that in N67EMs (P = 0.0037). The infection of HPV16 had inverse correlation with the overexpression of COX-2 in ESCCs (R = -0.321, P = 0.008). The HPV16 DNA in ESCC had no statistical correlation with P53 protein (R = -0.014, P = 0.9055) and the elevated expression of COX-2 had positive correlation with P53 protein in ESCC (R = 0.441, P = 0.000). No statistical correlation was observed between the infection of HPV16 and clinicopathological features in ESCCs including sex, age, tumor stage, and lymph node metastasis, respectively (P>0.05). The COX-2 had no statistical correlation with sex and age (P>0.05), but had association with tumor stage and lymph node metastasis, respectively (P<0.05). The expression of P53 protein had significant association with lymph node metastasis (P = 0.0005), but not with sex, age, and tumor stage, respectively (P>0.05). The overexpression of COX-2, infection of HPV16, and P53 protein in ESCC were not correlated with survival during the 5-year follow-up period (P>0.05).

CONCLUSION

We first concluded that the increased expression of COX-2 had inverse correlation with HPV16 in ESCC. COX-2, HPV16, and P53 had no significant effect on the survival of patients with ESCC. These observations might help us to further understand the significant association between HPV16 and other molecules involved in the carcinogenesis and progression of ESCC.

Cyclooxygenase-2 Gly587Arg variant is associated with differential enzymatic activity and risk of esophageal squamous-cell carcinoma

Functional SNPs in the COX-2 promoter region have been associated with susceptibility to esophageal squamous-cell carcinoma (ESCC). In this study, we investigated SNPs in the COX-2 coding region and their impact on risk of ESCC. The coding region of COX-2 in DNAs from 30 Han Chinese individuals was sequenced to identify SNPs. Different coding region variants identified were cloned and expressed in MCE-7 cells for the measurement of COX-2 enzymatic activity. Genotypes were determined by PCR-RFLP in 1026 patients with ESCC and 1270 controls and odds ratios (ORs) and 95% confidence intervals (CI) were computed by logistic regression model. A SNP at exon 10 (1759G>A, rs3218625) was identified, which causes (587)Gly to (587)Arg amino acid substitution. Enzymatic assays using different recombinant COX-2 variants showed that COX-2-(587)Arg had significantly higher activity towards arachidonic acid than COX-2-(587)Gly (13.8 +/- 3.2 U/mg vs. 11.2 +/- 2.4 U/mg; P = 0.012). Case-control analysis showed that 10.2% of ESCC patients carried the 1759A allele whereas only 5.4% of controls had this allele (P < 0.0001). No homozygous 1759AA genotype was presented in controls albeit two patients carrying this genotype. Multivariate logistic regression analysis revealed that subjects with at least one 1759A allele had increased risk for the development of ESCC (OR, 1.91; 95% CI, 1.39-2.62) compared with those with the 1759GG genotype. These results extend our previous findings and indicate that inherited variant in arachidonic acid-metabolizing enzyme, which results in heightened enzymatic activity, may confer susceptibility to ESCC.