Human papillomavirus (HPV) DNA methylation changes in HPV-associated head and neck cancer.

Despite the rising incidence, currently, there are no early detection methods for HPV-driven HNC (HPV-HNC). Cervical cancer studies suggest that HPV DNA methylation changes can be used as a biomarker to discriminate cancer patients from HPV-infected individuals. As such, this study was designed to establish a protocol to evaluate DNA methylation changes in HPV late genes and long control region (LCR) in saliva samples of HPV-HNC patients and HPV-positive controls. Higher methylation levels were detected in HPV late genes (L1 and L2) in both tumour and saliva samples of HPV-HNC patients compared with HPV-positive controls. Moreover, methylation patterns between tumours and corresponding saliva samples were observed to have a strong correlation (Passing-Bablok regression analysis; τ = 0.7483, P < 0.0001). Considering the differences between HNC and controls in methylation levels in late genes, and considering primer amplification efficiencies, 13 CpG sites located at L1 and L2 genes were selected for further evaluation. A total of 18 HNC saliva samples and 10 control saliva samples were assessed for the methylation levels in the selected sites. From the CpG sites evaluated statistically significant differences were identified for CpG sites at L2-CpG 6 (P = 0.0004), L1-CpG 3 (P = 0.0144), L1-CpG 2 (P = 0.0395) and L2-CpG 19 (P = 0.0455). Our pilot data indicate that higher levels of DNA methylation in HPV late genes are indicative of HPV-HNC risk, and it is a potential supplementary biomarker for salivary HPV detection-based HPV-HNC screening.

Profiling salivary miRNA expression levels in Fanconi anemia patients - a pilot study.

The overarching goal of this study is to predict the risk of developing oral squamous cell carcinoma (OSCC) in Fanconi anemia (FA) patients. We have compared the microRNA (miRNA, miR) expression levels in saliva samples from FA patients (n = 50) who are at a low-moderate and/or high risk of developing OSCC to saliva samples from healthy controls (n = 16). The miRNA expression levels in saliva samples were quantified using qPCR. We observed that miR-744, miR-150-5P, and miR-146B-5P had the best discriminatory capacity between FA patients and controls, with an area under the curve (AUC) of 94.0%, 92.9% and 85.3%, respectively. Our data suggest that miR-1, miR-146B-5P, miR-150-5P, miR-155-5P, and miR-744 could be used as panel to predict the risk of developing OSCC in FA patients, with a 89.3% sensitivity and a 68.2% specificity (AUC = 81.5%). Our preliminary data support the notion that the expression levels of salivary miRNAs have the potential to predict the risk of developing OSCC in FA patients and in the future may reduce deaths associated with OSCC.

Salivary micro RNAs as biomarkers for oropharyngeal cancer.

BACKGROUND: Despite the rising incidence, particularly of the human papillomavirus (HPV)-associated fraction of oropharyngeal cancer (OPC), there are no early detection methods for OPC. Considering the close association between saliva and head and neck cancers, this study was designed to investigate salivary micro RNA (miRNAs) associated with OPC, especially focusing on HPV-positive OPC. METHODS: Saliva was collected from OPC patients at diagnosis and patients were clinically followed up ≤5 years. Salivary small RNA isolated from HPV-positive OPC patients (N = 6), and HPV-positive (N = 4) and negative controls (N = 6) were analysed by next-generation sequencing to identify dysregulated miRNAs. Discovered miRNAs were validated by quantitative PCR using two different assays in a separate cohort of patients (OPC = 91, controls = 92). The relative expression was calculated considering SNORD-96A as the normalizer. Candidate miRNAs with diagnostic and prognostic potential were evaluated by generalized logistic regression. RESULTS: A panel consisting of nine miRNAs was identified to have the best diagnostic performance to discriminate HPV-positive OPC from HPV-positive controls (AUC- validation-1 = 94.8%, validation-2 = 98%). Further, a panel consisting of six miRNAs were identified to discriminate OPC from controls regardless of the HPV status (AUC- validation-1 = 77.2%, validation-2 = 86.7%). In addition, the downregulation of hsa-miR-7-5p was significantly associated with poor overall survival of OPC patients (HR = 0.638). A panel consisting of nine miRNAs were identified for the prediction of the overall survival of the OPC patients (log-rank test-p = 0.0008). CONCLUSION: This study highlights that salivary miRNAs can play an essential role in the detection and prognostication of OPC.

Analysis of human leukocyte antigen associations in human papillomavirus-positive and -negative head and neck cancer: Comparison with cervical cancer.

BACKGROUND: Although the majority of human papillomavirus (HPV) infections are cleared by the immune system, a small percentage of them progress to develop HPV-driven cancers. Cervical cancer studies highlight that HPV persistence and cancer risk are associated with genetic factors, especially at the human leukocyte antigen (HLA) genes. This study was conducted to investigate such associations in head and neck cancer (HNC). METHODS: In all, 192 patients with HNC and 384 controls were genotyped with the Infinium Global Screening Array (Illumina, Inc). HLA variants were imputed with SNP2HLA, and an association analysis was performed by logistic regression. RESULTS: HPV-positive HNCs were significantly associated with single-nucleotide polymorphisms (SNPs) at DRB1_32660090 (P = 1.728 × 10-6 ) and DRB1_32660116 (P = 1.728 × 10-6 ) and with the amino acid variant DRB1_11_32660115 (P = 1.728 × 10-6 ). None of these associations were observed in the HPV-negative cohort, and this suggested their specificity to convey risk for HPV-associated HNCs. In general, associations observed for HPV-negative HNC were relatively weak, and variants in the HLA-DPA1 region were the strongest among them (P = 4.531 × 10-4 ). Several lead signals reported by previous HNC genome-wide association studies, including SNPs rs3135001 (P = .012), rs1049055 (P = .012), and rs34518860 (P = .029) and allele HLA-DQB1*06 (P = .009), were replicated in the current study. However, these associations were limited to the HPV-positive HNC group. Several cervical cancer-associated HLA variants, including SNPs rs9272143 (P = .002) and rs9271858 (P = .002) and alleles HLA-B-1501 (P = .009) and HLA-B-15 (P = .015), were also exclusively associated with HPV-positive HNC. CONCLUSIONS: HPV-positive HNC risk is associated with distinct HLA variants, and some of them are shared by both cervical cancer and HPV-positive HNC. Human papillomavirus (HPV)-positive head and neck cancer (HNC) risk is associated with distinct human leukocyte antigen variants, and some of them are shared by both cervical cancer and HPV-positive HNC. LAY SUMMARY: Cervical cancer studies highlight that human papillomavirus (HPV)-driven cancer risk is linked with human leukocyte antigen (HLA) polymorphism. Hence, the current study was designed to investigate the HLA associations in HPV-positive and HPV-negative head and neck cancer (HNC) and compare these associations with cervical cancer. Several lead signals reported by previous HNC and cervical genome-wide association studies were replicated in the current study. However, these associations were limited to the HPV-positive HNC group, and this suggests that HPV-positive HNC risk is associated with distinct HLA variants, and some of them are shared by both cervical cancer and HPV-positive HNC.

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.

Overexpression of miRNA-9 enhances galectin-3 levels in oral cavity cancers.

Oral cavity cancer (OCC) is the predominant subtype of head and neck cancer (HNC) and has up to 50% mortality. Genome-wide microRNA (miR) sequencing data indicates overexpression of miR-9-5p in HNC tumours, however, the biological role of miR-9-5p in OCC is complex; it can either act as a tumour suppressor or an oncomir, regulating many target genes at the post-transcriptional level. We have investigated the overexpression of miR-9-5p in three OCC cell lines. We have evaluated its expression levels and Galectin-3 as potential biomarkers in saliva samples collected from controls and OCC patients. We found that over expression of miR-9-5p in OCC cell lines resulted in a significant reduction in cell proliferation and migration, and an increase in apoptosis, which was paralleled by an increase in Galectin-3 secretion and export of Galectin-3 protein. Our data are consistent with miR-9-5p being a modulator of Galectin-3 via the AKT/γ-catenin pathway. In addition, the positive correlation between the levels of miR-9-5p expression and secreted Galectin-3 in saliva reflects a similar relationship in vivo, and supports the utility of their integrative evaluation in OCC. Our findings indicate that both miR-9-5p and Galectin-3 are critical biomolecules in the progression of OCC.

Chemoradiation therapy changes oral microbiome and metabolomic profiles in patients with oral cavity cancer and oropharyngeal cancer.

BACKGROUND: Patients with oral cavity cancer (OCC) and oropharyngeal cancer (OPC) are often seen with locoregionally advanced disease requiring complex multimodality treatments. These treatments may have detrimental effects on the oral microbiome, which is critical to maintaining physiological balance and health. METHODS: The effects of different OCC and OPC treatment types on the oral microbiome and metabolomic profiles for 24-month post-treatment in patients with OCC and OPC were investigated using 16S rRNA gene amplicon next-generation sequencing and gas chromatography-mass spectrometry (GC-MS), respectively. RESULTS: Chemoradiation resulted in oral dysbiosis with specific depletion of genera which regulate the enterosalivary nitrate-nitrite-nitric oxide pathway. These data also correlate with the oral metabolomic profiles with nitric oxide-related precursor, modulator, or catalyst significantly downregulated in saliva samples from patients' postchemoradiation. CONCLUSIONS: Together, we have shown that oral dysbiosis due to the effects of chemoradiation could potentially have an impact on OCC and OPC patient's quality of life post-treatment.

DNA Methylation Changes in Human Papillomavirus-Driven Head and Neck Cancers.

Disruption of DNA methylation patterns is one of the hallmarks of cancer. Similar to other cancer types, human papillomavirus (HPV)-driven head and neck cancer (HNC) also reveals alterations in its methylation profile. The intrinsic ability of HPV oncoproteins E6 and E7 to interfere with DNA methyltransferase activity contributes to these methylation changes. There are many genes that have been reported to be differentially methylated in HPV-driven HNC. Some of these genes are involved in major cellular pathways, indicating that DNA methylation, at least in certain instances, may contribute to the development and progression of HPV-driven HNC. Furthermore, the HPV genome itself becomes a target of the cellular DNA methylation machinery. Some of these methylation changes appearing in the viral long control region (LCR) may contribute to uncontrolled oncoprotein expression, leading to carcinogenesis. Consistent with these observations, demethylation therapy appears to have significant effects on HPV-driven HNC. This review article comprehensively summarizes DNA methylation changes and their diagnostic and therapeutic indications in HPV-driven HNC.

An Occult HPV-Driven Oropharyngeal Squamous Cell Carcinoma Discovered Through a Saliva Test.

Oropharyngeal cancer (OPC) caused by human papillomavirus (HPV) is a rising global concern. Early lesions are small and are often located in difficult to access areas (such as the crypts of the tonsils or base of tongue). Unlike cervical cancer, there is no standard or routine screening program for HPV-driven OPC. HPV DNA from OPC tumors may shed directly into saliva, and this can be used as a biomarker for early diagnosis. In this study, we report the first-ever clinically occult OPC in an asymptomatic patient discovered through a saliva test. This case relied upon serial measurements of HPV-16 DNA in saliva, which fell to undetectable levels following low morbidity, curative treatment.

Oral HPV16 Prevalence in Oral Potentially Malignant Disorders and Oral Cavity Cancers.

The role of human papillomavirus type 16 (HPV16) in oral potentially malignant disorders (OPMD) and oral cavity carcinoma (OC) is still under debate. We investigated HPV16 prevalence in unstimulated saliva, oral rinse samples, oral swabs and tumour biopsies collected from OPMD (n = 83) and OC (n = 106) patients. HPV16 genotype, viral load, physical status (episomal vs. integrated) and tumour p16INK4a expression were determined. Oral HPV16 prevalence was higher in OC than in OPMD, but this difference was not statistically significant (7.5% (8/106) versus 3.6% (3/83), odds ratio (OR): 2.18, 95% confidence interval (CI): 0.56, 8.48, p = 0.26). There was a significant association (p < 0.05) between oral HPV16 infection and heavy tobacco consumption. Real-time PCR results indicated that no integration events occurred in either OPMD or OC cases based on the HPV16 E2/E6 ratio. HPV16 positive OPMD and OC patients had similar HPV16 E2 and E6 viral loads. The inter-rater agreement between tumour p16INK4a expression and oral HPV16 infection was considered as fair (k = 0.361) for OC. Our data suggest that the involvement of HPV16 in oral carcinogenesis is limited.

Isolation and Quantification of MicroRNAs from Human Saliva.

Oral premalignant disorders (OPMD) have relatively high malignant transformation rates to Oral Cancers (OC). Oral carcinogenesis is a multistep process that originates as epithelial hyperplasia followed by epithelial dysplasia, leading to fully malignant phenotypes. Early detection can be lifesaving but is currently not possible due to the lack of early diagnostic tools. The current diagnostic methods such as biopsy sampling, tumor tissue staining, and imaging techniques require skilled personnel and are invasive, painful, time-consuming, and expensive. Saliva has gained momentum as the diagnostic fluid of the future due to its noninvasive nature, ease of sampling, multiple samples can be collected with ease and more importantly does not require skilled personnel. The use of saliva in cancer diagnostics is an emerging and an expanding field. MicroRNA (miRNA) play a role in cancer initiation and progression and the expression changes of miRNA have been investigated as a potential biomarker in cancer studies. In this chapter, we describe a robust and cost-effective protocol to isolate and enrich miRNA from saliva samples. Profiling miRNAs in saliva samples can form part of the clinical management of OPMD and OC patients in the future.

Unlocking the Potential of Saliva-Based Test to Detect HPV-16-Driven Oropharyngeal Cancer.

The incidence of human papillomavirus (HPV)-positive oropharyngeal cancer (OPC) is rising in high-income countries, including Australia. Increasing evidence suggests that accurate HPV testing is pivotal for clinical decision making and treatment planning in these patients. Recently, the eighth edition of the American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) tumor-node-metastasis (TNM) staging system for OPC (based on the p16INK4a (p16) status) was proposed and has been implemented. However, the applicability of this new staging system is still far from clear. In our study, n = 127 OPC patients from Queensland, Australia were recruited, and the tumor p16 expression in these patients was examined using immunohistochemical (IHC) analysis. HPV-16 genotyping, viral load, and physical status (episomal versus integrated) in the saliva samples of OPC patients were determined using the qPCR method. A good inter-rater agreement (k = 0.612) was found between tumor p16 expression and oral HPV-16 infection in OPC. Importantly, according to the eighth edition staging system, HPV-16 DNA viral load (>10 copies/50 ng) was significantly associated with the advanced stages of OPC. In concordance with previous studies, a mixed HPV-16 form (partially or fully integrated) was predominately found in OPC patients. Taken together, our data support HPV-16 detection in saliva as a screening biomarker to identify people within the community who are at risk of developing OPC.

Gamma-Tocotrienol Induces Apoptosis in Prostate Cancer Cells by Targeting the Ang-1/Tie-2 Signalling Pathway.

Emerging evidence suggests that gamma-tocotrienol (γ-T3), a vitamin E isomer, has potent anti-cancer properties against a wide-range of cancers. γ-T3 not only inhibited the growth and survival of cancer cells in vitro, but also suppressed angiogenesis and tumour metastasis under in vivo conditions. Recently, γ-T3 was found to target cancer stem cells (CSCs), leading to suppression of tumour formation and chemosensitisation. Despite its promising anti-cancer potential, the exact mechanisms responsible for the effects of γ-T3 are still largely unknown. Here, we report the identification of Ang-1 (Angiopoietin-1)/Tie-2 as a novel γ-T3 downstream target. In prostate cancer cells, γ-T3 treatment leads to the suppression of Ang-1 at both the mRNA transcript and protein levels. Supplementing the cells with Ang-1 was found to protect them against the anti-CSC effect of γ-T3. Intriguingly, inactivation of Tie-2, a member receptor that mediates the effect of Ang-1, was found to significantly enhance the cytotoxic effect of γ-T3 through activation of AMP-activated protein kinase (AMPK) and subsequent interruption of autophagy. Our results highlighted the therapeutic potential of using γ-T3 in combination with a Tie-2 inhibitor to treat advanced prostate cancer.

High-risk human papillomavirus detection in oropharyngeal cancers: Comparison of saliva sampling methods.

BACKGROUND: Accumulating evidence has suggested the utility of salivary oral rinse as a diagnostic fluid to detect oral human papillomavirus (HPV) DNA, but there are many methods for collecting saliva. METHODS: Salivary oral rinse and unstimulated whole mouth saliva samples were collected from 45 oropharyngeal cancer (OPC) patients. RESULTS: We show a positive correlation of HPV-16 E2 (r = 0.95, P < 0.0001) and E6/7 (r = 0.93, P < 0.0001) relative copy number as well as HPV genotypes in both sample methods. There was a significant correlation between the two sample methods in the ratio of HPV16 E2 to E6/7 DNA (r = 0.46, P < 0.01). Consistent with previous studies, a mixed HPV-16 form (episomal and integrated) was commonly found in both saliva and tumor samples. CONCLUSION: Detection of HPV in saliva samples collected by either method yielded comparable results, and showed good sensitivity for detection of HPV derived from OPC.

Salivary exosomes as potential biomarkers in cancer.

Over the past decade, there has been emerging research in the field of extracellular vesicles, especially those originating from endosomes, referred to as 'exosomes. Exosomes are membrane-bound nanovesicles secreted by most cell types upon fusion of multivesicular bodies (MVBs) to the cell plasma membrane. These vesicles are present in almost all body fluids such as blood, urine, saliva, breast milk, cerebrospinal and peritoneal fluids. Exosomes participate in intercellular communication by transferring the biologically active molecules like proteins, nucleic acids, and lipids to neighboring cells. Exosomes are enriched in the tumour microenvironment and growing evidence demonstrates that exosomes mediate cancer progression and metastasis. Given the important biological role played by these nanovesicles in cancer pathogenesis, these can be used as ideal non-invasive biomarkers in detecting and monitoring tumours as well as therapeutic targets. The scope of the current review is to provide an overview of exosomes with a special focus on salivary exosomes as potential biomarkers in head and neck cancers.

The overexpression of salivary cytokeratins as potential diagnostic biomarkers in head and neck squamous cell carcinomas.

BACKGROUND: Cytokeratin (CK) intermediate filaments are demonstrated to have enormous potential in regulating cellular motility and cancer progression. There are more than 20 divergent CKs that have been identified, of which CK 8, 17, 18 and 19 are reported to be elevated in the tumour biopsies of head and neck cancer squamous cell carcinoma (HNSCC) patients. However, CK expression profiles in the saliva of HNSCC patients have not been investigated. We aim to investigate the mRNA expression profiles of CKs in saliva collected from healthy controls, HPV-negative and -positive HNSCC patients. METHODS: Oral rinse samples were collected from 42 cancer-free healthy controls (age-matched) and patients who have been diagnosed with HPV-negative (n = 20) and -positive (n = 48) HNSCC. RESULTS: Here, we report that the mRNA expression profiles of CKs differed in saliva collected from healthy controls and HNSCC patients. The mRNA expression levels of CK 8 and 18 were significantly elevated in saliva collected from HPV-negative HNSCC patients; whilst, CK 17 and 19 were expressed at a higher mRNA level in saliva collected from HPV-positive HNSCC patients compared to healthy controls. Importantly, receiver operating characteristic (ROC) analysis showed salivary CK 8 and 18 to have superior sensitivity and specificity in discriminating the HPV-negative HNSCC patients from healthy controls (80% and 86%) as well as between HPV-negative and -positive HNSCC patients (75% and 81%). CONCLUSION: In summary, we have demonstrated that an aberrant expression of salivary CKs may serve as a potential non-invasive diagnostic biomarker in HNSCC.

A Pilot Study into the Association between Oral Health Status and Human Papillomavirus-16 Infection.

BACKGROUND: Over the next 20 years, oropharyngeal cancers (OPC) will represent the majority of head and neck cancers (HNCs) in the United States. It is estimated that human papillomavirus (HPV) may account for as much as 70% to 80% of OPCs in North America and in certain parts of Europe. It is hence crucial to understand the disease risk factors and natural history of oral HPV infections. We hypothesized that poor oral health (by measures such as poor oral hygiene and periodontal disease) leads to a higher degree of oral HPV-16 infections within a patient cohort from a dental school clinic. This study aims to test this hypothesis and gauge possible disease associations before larger scale studies. SUBJECTS AND METHODS: 223 participants were recruited in this study from the University of Queensland Dental School clinic. Clinical oral health parameters (such as oral hygiene measures and periodontal disease measurements) have been examined and determined by dental professionals. We have collected oral rinse samples from these volunteers. RESULTS: 10 (4.5%) out of 223 participants were found to have HPV-16 DNA in their oral rinse samples using NB2 endpoint PCR and Sanger sequencing. Within the HPV-16 DNA positive subjects, 7 (70%) and 3 (30%) were associated with poor oral hygiene and periodontal disease, respectively. CONCLUSION: Our results show a trend towards a positive correlation between oral HPV-16 infection and poor clinical oral health status.

Adipocytes promote prostate cancer stem cell self-renewal through amplification of the cholecystokinin autocrine loop.

Obesity has long been linked with prostate cancer progression, although the underlying mechanism is still largely unknown. Here, we report that adipocytes promote the enrichment of prostate cancer stem cells (CSCs) through a vicious cycle of autocrine amplification. In the presence of adipocytes, prostate cancer cells actively secrete the peptide hormone cholecystokinin (CCK), which not only stimulates prostate CSC self-renewal, but also induces cathepsin B (CTSB) production of the adipocytes. In return, CTSB facilitates further CCK secretion by the cancer cells. More importantly, inactivation of CCK receptor not only suppresses CTSB secretion by the adipocytes, but also synergizes the inhibitory effect of CTSB inhibitor on adipocyte-promoted prostate CSC self-renewal. In summary, we have uncovered a novel mechanism underlying the mutual interplay between adipocytes and prostate CSCs, which may help explaining the role of adipocytes in prostate cancer progression and provide opportunities for effective intervention.

Tie-2 regulates the stemness and metastatic properties of prostate cancer cells.

Ample evidence supports that prostate tumor metastasis originates from a rare population of cancer cells, known as cancer stem cells (CSCs). Unfortunately, little is known about the identity of these cells, making it difficult to target the metastatic prostate tumor. Here, for the first time, we report the identification of a rare population of prostate cancer cells that express the Tie-2 protein. We found that this Tie-2High population exists mainly in prostate cancer cell lines that are capable of metastasizing to the bone. These cells not only express a higher level of CSC markers but also demonstrate enhanced resistance to the chemotherapeutic drug Cabazitaxel. In addition, knockdown of the expression of the Tie-2 ligand angiopoietin (Ang-1) led to suppression of CSC markers, suggesting that the Ang-1/Tie-2 signaling pathway functions as an autocrine loop for the maintenance of prostate CSCs. More importantly, we found that Tie-2High prostate cancer cells are more adhesive than the Tie-2Low population to both osteoblasts and endothelial cells. Moreover, only the Tie-2High, but not the Tie-2Low cells developed tumor metastasis in vivo when injected at a low number. Taken together, our data suggest that Tie-2 may play an important role during the development of prostate tumor metastasis.