Clinical, pathological and molecular determinants in squamous cell carcinoma of the oral cavity

Diagnostic potential of salivary IL-1β, IL-8, SAT, S100P, and OAZ1 in oral squamous cell carcinoma, oral submucous fibrosis, and oral lichen planus based on findings from a Sri Lankan cohort

The research examined the salivary concentrations of various biomarkers, such as OAZ1, SAT, S100P, IL-1β, and IL-8 aiming to detect early-stage oral squamous cell carcinoma (OSCC). These biomarkers show potential as indicators for detecting both pre-cancerous and cancerous states within the oral cavity. Analyzing these specific molecules in saliva could help clinicians enhance diagnostic accuracy and refine early detection methods for OSCC. The research encompassed a cohort of nine OSCC patients, ten with oral submucous fibrosis (OSF), eleven individuals with oral lichen planus (OLP), and ten healthy controls. The study focused on assessing the expression levels of key biomarkers-IL-1β, IL-8, SAT, S100P, and OAZ1 mRNA-in extracellular RNA extracted from saliva samples. This evaluation was conducted using real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) with sequence-specific primers. Additionally, receiver operating characteristic curve (ROC) curve analysis was employed to gauge the efficacy of these biomarkers in detecting OSCC. Based on the results we observe, when these five biomarkers are used together, they give a 90% predictive probability for patients with OLP, an 80% predictive probability for OSF, and an impressive 100% predictive probability for patients with OSCC (AUC = 1.000, p = 0.000). This study demonstrates the efficacy of salivary transcriptome diagnostics in detecting OSCC. This novel clinical technique has the potential to be a powerful, efficient, and reliable tool for early detection of cancer. Salivary transcriptomes can be further analyzed to evaluate their effectiveness in other important illness contexts and for regular health monitoring.

Effects of Tetrandrine on the Apoptosis of Cisplatin-resistant Oral Cancer Cells

Background

Cisplatin, the first-line drug for chemotherapy, often has limited treatment efficacy because of resistance and cancer recurrence mechanisms. Tetrandrine is a unique secondary metabolite of Stephania tetrandra. As a traditional Chinese medicine agent, tetrandrine has been reported to have antioxidant, anti-inflammatory, antitumor, and antiangiogenesis activities and has been shown to inhibit the proliferation and angiogenesis of colorectal, lung, and breast cancer cells; potential mechanisms underlying its activities include the promotion of tumor cell apoptosis, promotion of cell cycle arrest, and intensification of reactive oxygen species (ROS) production.

Objectives

The main treatments for oral cancer are chemotherapy, surgery, and radiotherapy; these treatments are often used in combination. Cancer cells easily develop cisplatin resistance; therefore, we investigated tetrandrine’s potential as a therapy for overcoming resistance to oral cancer drugs.

Materials and Methods

We used the cisplatin-resistant oral cancer CAR cell line (CAL27) as a research objected and applied inhibitor treatment to clarify the role of tetrandrine in cell death and mitochondrial dysfunction.

Results

Tetrandrine could effectively inhibit CAR cell proliferation and induce apoptosis, with a corresponding increase in ROS production in mitochondria. Moreover, tetrandrine increased caspase-9 and caspase-3 activity in CAR cells and induced apoptotic mRNA, caspase-3/-9, AIF, and Endo G overexpression. Our results indicate that tetrandrine induces apoptosis in CAR cells through a mitochondrial-dependent signaling pathway.

Chronic Alcohol Exposure Promotes Cancer Stemness and Glycolysis in Oral/Oropharyngeal Squamous Cell Carcinoma Cell Lines by Activating NFAT Signaling

Alcohol consumption is associated with an increased risk of several cancers, including oral/oropharyngeal squamous cell carcinoma (OSCC). Alcohol also enhances the progression and aggressiveness of existing cancers; however, its underlying molecular mechanism remains elusive. Especially, the local carcinogenic effects of alcohol on OSCC in closest contact with ingestion of alcohol are poorly understood. We demonstrated that chronic ethanol exposure to OSCC increased cancer stem cell (CSC) populations and their stemness features, including self-renewal capacity, expression of stem cell markers, ALDH activity, and migration ability. The ethanol exposure also led to a significant increase in aerobic glycolysis. Moreover, increased aerobic glycolytic activity was required to support the stemness phenotype of ethanol-exposed OSCC, suggesting a molecular coupling between cancer stemness and metabolic reprogramming. We further demonstrated that chronic ethanol exposure activated NFAT (nuclear factor of activated T cells) signaling in OSCC. Functional studies revealed that pharmacological and genetic inhibition of NFAT suppressed CSC phenotype and aerobic glycolysis in ethanol-exposed OSCC. Collectively, chronic ethanol exposure promotes cancer stemness and aerobic glycolysis via activation of NFAT signaling. Our study provides a novel insight into the roles of cancer stemness and metabolic reprogramming in the molecular mechanism of alcohol-mediated carcinogenesis.

TRF2 Overexpression at the Surgical Resection Margin: A Potential Predictive Biomarker in Oral Squamous Cell Carcinoma for Recurrence

Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers in India with high incidence rate in eastern region due to habits of tobacco, pan and gutkha chewing habits. In majority of OSCC, the cases were presented to clinicians at later stages of the disease which leads to increased mortality. In addition presence of minimal residual disease also significantly contributed towards disease progression. Therefore, identification of potential biomarker for prognostic stratification of patients with high risk of disease recurrence and appropriate management is utmost necessary. In this study, 80 OSCC patients were included and their tumour specimen along with cut margin (CM) was collected after surgical excision. Immunohistochemistry (IHC) was performed to check expression of TRF2 in tumour and CM of OSCC patients. Statistical analysis was carried out using SPSS based on clinical and pathological records. It was observed that 27 OSCC patients developed recurrence during the period of the study (2012-2016). It was observed that, in 34 cases (42.25%) TRF2 expression was positive in tumour, while in 46 cases (57.75%), it was negative, while it was just reverse at CM, respectively. The odds of recurrence among patients having high levels of TRF2 in CM were 2.6 times higher than the odds of recurrence among patients having lower levels of TRF2 in CM. In conclusion, this study showed that TRF2 at surgical cut margin has a prognostic significance and can be used as a molecular marker for predicting survival in OSCC patients.

Promoter Hypermethylation of LATS1 Gene in Oral Squamous Cell Carcinoma (OSCC) among North Indian Population

BACKGROUND

LATS1 (Large Tumor Suppressor, isoform 1) is a gene that forms a complex with the cyclin-dependent kinase, CDK1, and regulates cell cycle progression. Genetic modifications lead to a loss in the activity of LATS1 gene. OSCC is the most commonly emerging cancer caused by genetic as well as epigenetic changes. Epigenetics changes vary from one population to another because these are influenced by dietary factors and environmental factors.  Tobacco chewing and smoking has been reported as major risk factors in OSCC. No report was found in the previous literature showing promoter hypermethylation of LATS1 gene.

METHODS

A total of 50 OSCC patients and 20 normal individuals were recruited in this study. Blood samples (50) from OSCC patients and blood samples (20) from healthy individuals as controls were used in the present study. Isolation of genomic DNA was carried out from blood using the standard phenol-chloroform extraction. Further Isolated DNA was modified with sodium bisulfite using the agarose bead method and finally, the methylation studies of LATS1 gene were carried out using Methylation-Specific PCR (MSP-PCR).

RESULTS

19 out of 50 patients (38.0%) were found to be methylated for LATS1 gene.; a statistically significant result was obtained (p -value= < 0.05) with an odds ratio of 0.37 in cases compared to controls. The status of methylation of LATS1 genes was also found to be statistically significantly associated with smokers and tobacco chewers (p-value = < 0.05). The methylation of LATS1 gene showed a significant risk of developing OSCC in patients.

CONCLUSION

These results suggest that the LATS1 gene may provide a better alternative as a diagnostic biomarker. This is the first report on the promoter hypermethylation of LATS1 gene in OSCC patients among the North Indian population.<br />.

Overproduced CPSF4 Promotes Cell Proliferation and Invasion via PI3K-AKT Signaling Pathway in Oral Squamous Cell Carcinoma

PURPOSE

Invasion and metastasis are major challenges in the treatment of oral cancer. We hypothesize that cleavage and polyadenylation specific factor 4 (CPSF4), a key mediator of cell growth and metastasis in several types of cancers, contributes to oral squamous cell carcinoma (OSCC) pathogenesis.

MATERIALS AND METHODS

The expression and production of CPSF4 in OSCC cell lines and tumor tissues were assessed by RT-PCR and western blot, respectively. The relationships between CPSF4 production and OSCC clinicopathological features were analyzed using immunohistochemistry. The effects of CPSF4 on viability, proliferation, migration, invasion, cell cycle distribution, and apoptosis of OSCC cells were measured by MTS assay, colony formation assay, wound-healing, transwell invasion assay, flow cytometry, and cell apoptosis assay, respectively. Western blot analysis was used to assess alteration of PI3K-AKT pathway member levels in cell lines transfected with CPSF4 siRNA. Mice xenograft models were used to determine the effect of CPSF4 on OSCC tumor growth in vivo.

RESULTS

CPSF4 was highly expressed in OSCC cell lines and tumor tissues compared with adjacent normal oral tissues. High CPSF4 expression was strongly correlated with vascular invasion (P = .004), distant metastasis (P = .001), and TNM stages (P = .001). Moreover, reduction of CPSF4 levels contributed to the inhibition of cell viability, proliferation, invasion and migration, and the induction of apoptosis in OSCC cell lines. Reduction of CPSF4 levels results in OSCC cell cycle arrest in G1 phase by targeting c-Myc. CPSF4 contributed to proliferation inhibition via PI3K-AKT signaling pathway. Reduction of CPSF4 levels inhibits OSCC tumor growth in vivo.

CONCLUSIONS

Our results suggest that CPSF4 supports OSCC invasion and metastasis and may be a promising therapeutic target for OSCC.

Prognostic factors analysis for oral cavity cancer survival in the Netherlands and Taiwan using a privacy-preserving federated infrastructure

The difference in incidence of oral cavity cancer (OCC) between Taiwan and the Netherlands is striking. Different risk factors and treatment expertise may result in survival differences between the two countries. However due to regulatory restrictions, patient-level analyses of combined data from the Netherlands and Taiwan are infeasible. We implemented a software infrastructure for federated analyses on data from multiple organisations. We included 41,633‬ patients with single-tumour OCC between 2004 and 2016, undergoing surgery, from the Taiwan Cancer Registry and Netherlands Cancer Registry. Federated Cox Proportional Hazard was used to analyse associations between patient and tumour characteristics, country, treatment and hospital volume with survival. Five factors showed differential effects on survival of OCC patients in the Netherlands and Taiwan: age at diagnosis, stage, grade, treatment and hospital volume. The risk of death for OCC patients younger than 60 years, with advanced stage, higher grade or receiving adjuvant therapy after surgery was lower in the Netherlands than in Taiwan; but patients older than 70 years, with early stage, lower grade and receiving surgery alone in the Netherlands were at higher risk of death than those in Taiwan. The mortality risk of OCC in Taiwanese patients treated in hospitals with higher hospital volume (≥ 50 surgeries per year) was lower than in Dutch patients. We conducted analyses without exchanging patient-level information, overcoming barriers for sharing privacy sensitive information. The outcomes of patients treated in the Netherlands and Taiwan were slightly different after controlling for other prognostic factors.

An Updated Review of Oral Cancer Stem Cells and Their Stemness Regulation

Cancer stem cells (CSCs; also known as tumor-initiating cells) are a small population of cancer cells that retain characteristics similar to those of normal stem cells. CSCs are known to be responsible for metastasis, drug resistance, and cancer recurrence. Thus, controlling CSCs may provide an effective therapeutic intervention that inhibits tumor growth and aggressiveness. Despite the importance of targeting CSCs in cancer therapy, the detailed nature of oral CSCs remains underexplored. This article reviews the current understanding of oral CSCs, with emphasis on recent advances in novel signaling pathways involved in their stemness regulation.

NFATc3 plays an oncogenic role in oral/oropharyngeal squamous cell carcinomas by promoting cancer stemness via expression of OCT4

Nuclear factor of activated T cells (NFATc1-c4), a family of transcription factors, is involved in many biological processes by regulating various downstream target genes. However, their role in cancer progression remains controversial. We here report that NFATc3 is the dominant isoform of NFAT in human oral epithelial cells, and its expression was increased in a stepwise manner during the progression of oral/oropharyngeal squamous cell carcinoma (OSCC). More importantly, NFATc3 was highly enriched in self-renewing cancer stem-like cells (CSCs) of OSCC. Increased expression of NFATc3 was required for the maintenance of CSC self-renewal, as NFATc3 inhibition suppressed tumor sphere formation in OSCC cells. Conversely, ectopic NFATc3 expression in non-tumorigenic immortalized oral epithelial cells resulted in the acquisition of self-renewal and increase in CSC phenotype, such as enhanced ALDH1^HIGH cell population, mobility and drug resistance, indicating the functional role of NFATc3 in the maintenance of CSC phenotype. NFATc3 expression also converted the non-tumorigenic oral epithelial cells to malignant phenotypes. Mechanistic investigations further reveal that NFATc3 binds to the promoter of OCT4, a stemness transcription factor, for its activation, thereby promoting CSC phenotype. Moreover, suppression of OCT4 abrogated CSC phenotype in the cell with ectopic NFATc3 overexpression and OSCC, and ectopic OCT4 expression sufficiently induced CSC phenotype. Our study indicates that NFATc3 plays an important role in the maintenance of cancer stemness and OSCC progression via novel NFATc3-OCT4 axis, suggesting that this axis may be a potential therapeutic target for OSCC CSCs.

LATS1/2 kinases trigger self-renewal of cancer stem cells in aggressive oral cancer

Cancer stem cells (CSCs), which play important roles in tumor initiation and progression, are resistant to many types of therapies. However, the regulatory mechanisms underlying CSC-specific properties, including self-renewal, are poorly understood. Here, we found that LATS1/2, the core Hippo pathway-kinases, were highly expressed in the oral squamous cell carcinoma line SAS, which exhibits high capacity of CSCs, and that depletion of these kinases prevented SAS cells from forming spheres under serum-free conditions. Detailed examination of the expression and activation of LATS kinases and related proteins over a time course of sphere formation revealed that LATS1/2 were more highly expressed and markedly activated before initiation of self-renewal. Moreover, TAZ, SNAIL, CHK1/2, and Aurora-A were expressed in hierarchical, oscillating patterns during sphere formation, suggesting that the process consists of four sequential steps. Our results indicate that LATS1/2 trigger self-renewal of CSCs by regulating the Hippo pathway, the EMT, and cell division.

The role of NF-κB and miRNA in oral cancer and cancer stem cells with or without HPV16 infection

A small subpopulation of cancer stem-like cells (CSCs) present in almost all tumors is responsible for drug resistance and tumor recurrence. The role of NF-kB and miRNA in close association with essential risk factors, tobacco, alcohol and high risk HPV infection during oral carcinogenesis and its prognosis is not well understood. We have isolated cancer stem like SP cells from both HPV+/-ve oral squamous cell carcinoma (OSCC) cell lines and primary tumors, which formed orospheres, expressed stemness markers Oct4, Sox-2, CD133 and CD117. These cells showed differentially upregulated expression of NF-kB proteins and selective overexpression of viral oncogenes E6/E7 only in HPV16+ve cells which formed higher number of orospheres, overexpressed c-Rel and selectively activated p65 that heterodimerized with p50 to show higher DNA binding activity. Further, selective over expression of miR-21 and miR-155 and downregulation of miR-34a were demonstrated by HPV+ve CSCs which overexpress HPV16 oncogene E6 that is responsible for the maintenance of stemness. While, HPV-ve CSCs show exclusively p50 homodimeriztion, poor differentiation and worst prognosis, HPV infection induced participation of p65 along with deregulated expression of specific miRNAs led to well differentiation of tumors and better prognosis.

Orai1 promotes tumor progression by enhancing cancer stemness via NFAT signaling in oral/oropharyngeal squamous cell carcinoma

Emerging evidence indicates that Orai1, a key calcium channel for store-operated Ca²⁺ entry, is associated with human cancer. However, the underlying mechanism by which Orai1 regulates cancer progression remains unknown. Here we report that intracellular level of Orai1 is increased in a stepwise manner during oral/oropharyngeal carcinogenesis and highly expressed in cancer stem-like cell (CSC)-enriched populations of human oral/oropharyngeal squamous cell carcinoma (OSCC). Ectopic Orai1 expression converted non-tumorigenic immortalized oral epithelial cells to malignant cells that showed CSC properties, e.g., self-renewal capacity, increased ALDH1^HIGH cell population, increased key stemness transcription factors, and enhanced mobility. Conversely, inhibition of Orai1 suppressed tumorigenicity and CSC phenotype of OSCC, indicating that Orai1 could be an important element for tumorigenicity and stemness of OSCC. Mechanistically, Orai1 activates its major downstream effector molecule, NFATc3. Knockdown of NFATc3 in the Orai1-overexpressing oral epithelial cells abrogates the effect of Orai1 on CSC phenotype. Moreover, antagonist of NFAT signaling also decreases CSC phenotype, implying the functional importance of Orai1/NFAT axis in OSCC CSC regulation. Our study identifies Orai1 as a novel molecular determinant for OSCC progression by enhancing cancer stemness, suggesting that inhibition of Orai1 signaling may offer an effective therapeutic modality against OSCC.

Prognosis of neutrophil-to-lymphocyte ratio in clinical early-stage tongue (cT1/T2N0) cancer

BACKGROUND

Inflammation plays a role in the development of cancer. This study aims to analyze the prognostic value of the neutrophil-to-lymphocyte ratio (NLR) and other clinicopathological determinants in early-stage (cT1/T2N0) tongue cancer.

MATERIALS AND METHODS

A total of 262 patients were selected from our institute's cancer database between 2004 and 2011. Optimal cutoff value of NLR and lymph node density (LND) were determined statistically using receiver operating characteristic curve analysis for survival prediction. The 5-year overall survival (OS), disease-specific survival (DSS), and disease-free survival (DFS) rates were estimated using the Kaplan-Meier method.

RESULTS

The results showed that, in this cohort, the optimal cutoff value of NLR was 2.95 and for LND, it was 0.031. Patients with NLR ≥2.95 correlated significantly with positive N classification (P=0.011), T2 classification (P=0.007), positive perineural invasion (P<0.001), and a tumor thickness of >5 mm (P=0.005). The 5-year OS among patients with NLR <2.95 was much higher than that in patients with NLR ≥2.95 (P<0.001). Similarly, the 5-year DSS among patients with NLR <2.95 was much higher than that in patients with NLR ≥2.95 (P=0.002). The 5-year DFS among patients with NLR <2.95 was much higher than that in patients with NLR ≥2.95 (P=0.004). The 5-year OS, DSS, and DFS were significantly reduced among patients with LND >0.031 compared to those with LND <0.031, respectively. In multivariate analysis, NLR, LND, and tumor thickness were independent prognostic factors for OS.

CONCLUSION

Pretreatment NLR ≥2.95 is significantly correlated with a larger tumor, positive neck lymph node metastasis, and positive perineural invasion. Importantly, it indicates reduced survival rate. Therefore, if the NLR ≥2.95 in early-stage (cT1/T2N0) tongue cancer is noted preoperatively, it reveals more invasive tumor behavior clinically. Then, aggressive treatments, including elective neck dissection, become necessary.

Expression of MAGE-A1-A12 subgroups in the invasive tumor front and tumor center in oral squamous cell carcinoma

MAGE-A proteins are highly expressed in oral squamous cell carcinoma (OSCC) and are promising targets for cancer immunotherapy. This study examined the presence of MAGE-A expression within the tumor center (TC) and tumor invasive front (TIF) and evaluated its relationship to poor prognosis. The expression rate of each MAGE-A subtype, A1-A12, was examined in 68 OSCCs at the TIF and TC. Slides (1-µm) of tissue microarrays (diameter =0.6 mm) were immunohistochemically stained, and the findings were correlated to clinical data. Approximately 95% of the tumors had MAGE-A expression. Higher expression in the TC was shown significantly for MAGE-A1, -A5, -A6, -A9 and -A12 (P<0.05). MAGE-A2 and -A3 exhibited the opposite behavior (not significant, P>0.05). Age, tumor size, grade and survival time were not associated with the expression of certain MAGE-A subgroups. When expression in the whole tumor tissue was considered, only MAGE-A1 was expressed at a significantly higher rate in male patients (P=0.034). At the TIF, MAGE-A9 and the UICC disease stage were significantly correlated (P=0.0263), and MAGE-A6 and the UICC disease stage exhibited a strong trend (P=0.0596). The expression of MAGE-A3, -A4, -A5, -A9 and -A11 was significantly associated with lymph node metastasis, while MAGE-A4 was expressed in all regions of the tumors (TIF and TC). This study showed that higher expression of most MAGE-A antigens occurred at the TC rather than at the TIF. MAGE‑A1, -A3, -A4, -A5, -A9 and -A11 were significantly associated with clinically advanced stages of disease and seem to be of particular interest.

Human papillomavirus 16 (HPV16) enhances tumor growth and cancer stemness of HPV-negative oral/oropharyngeal squamous cell carcinoma cells via miR-181 regulation

High-risk human papillomaviruses (e.g., HPV16, HPV18) are closely associated with the development of head and neck cancers including oral/oropharyngeal squamous cell carcinoma (OSCC). We previously demonstrated immortalization of normal human oral keratinocytes by introducing high-risk HPV whole genome, suggesting that HPV infection plays an important role in the early stage of oral carcinogenesis. Although HPV infection may occur in different stages of cancer development, roles of HPV in exacerbating malignant phenotypes in already-transformed cells in the context of cancer stemness are not clearly defined. In this study, we investigated the role of HPV16 in promoting the virulence of HPV-negative OSCC. Introducing HPV16 whole genome in HPV-negative OSCC increased malignant growth and self-renewal capacity, a key characteristic of cancer stem cells (CSCs). HPV16 also enhanced other CSC properties, including aldehyde dehydrogenase 1 (ALDH1) activity, migration/invasion, and CSC-related factor expression. Mechanistically, we found that HPV16 inhibited the expression of miR-181a and miR-181d (miR-181a/d) at the transcriptional level. Ectopic expression of miR-181a/d decreased anchorage independent growth and CSC phenotype of HPV16-transfected OSCC. Furthermore, silencing of miR-181a/d target genes, i.e., K-ras and ALDH1, abrogated the effects of HPV16 in HPV16-transfected OSCC, supporting the functional importance of HPV16/miR-181a/d axis in HPV-mediated oral carcinogenesis. Our study suggests that high-risk HPV infection further promotes malignancy in HPV-negative OSCC by enhancing cancer stemness via miR-181a/d regulation. Consequently, miR-181a/d may represent a novel therapeutic agent for the treatment of HPV-positive OSCC.

Triple-positive pathologic findings in oral cavity cancer are related to a dismal prognosis

OBJECTIVES/HYPOTHESIS

Perineural invasion (PNI), lymphovascular invasion (LVI), and extracapsular spread (ECS) of lymph nodes are adverse histopathologic factors among patients with oral cancer. We analyzed the clinical impact of the combination of PNI, LVI, and ECS among patients with oral cancer.

STUDY DESIGN

Retrospective analysis of patients with oral cancer that was treated primarily with surgery with at least 5 years of follow-up data in a tertiary referral center.

METHODS

In total, 554 patients diagnosed with oral cavity squamous cell carcinoma who underwent operations consecutively between 2006 and 2008 in our hospital were enrolled. Clinical characteristics, 5-year survival rates, and local/regional control rates were analyzed.

RESULTS

There were 41 females and 513 males. Patients with PNI, LVI, or ECS presented pathologically had 5-year overall survival rates of 58.4%, 50.4%, and 31.4%, respectively. Patients with both ECS and PNI or both ECS and LVI presented had 5-year overall survival rates of 31.5% and 22.2%, respectively. Patients presenting with triple-positive status (PNI, LVI, and ECS) had only a 20.0% 5-year overall survival rate. The 5-year local/regional control rate for patients with both ECS and PNI or both ECS and LVI was 26% and 44.4%, respectively; for all three factors, it was 26.7%.

CONCLUSION

Patients with triple-positive status (PNI, LVI, ECS), ECS and PNI, or ECS and LVI experienced very low 5-year local/regional control rates, 5-year overall, and disease-specific survival rates. Novel interventions are necessary to improve these clinical outcomes.

LEVEL OF EVIDENCE

4.

Evidence that the genetic polymorphism rs1412115 on chromosome 10 is associated with risk for oral squamous cell carcinoma

A genome-wide association study on schizophrenia in Jewish population discovered a novel single nucleotide polymorphism (SNP), rs1412115, on chromosome 10. It has been proved that neuropilin-1 (NRP-1) gene located on chromosome 10, tightly close to rs1412115, is associated with increased risk for oral squamous cell carcinoma (OSCC). In the present study, we hypothesized that SNP rs1412115:A>G is associated with increased risk for OSCC. We therefore genotyped this polymorphism in 295 patients with OSCC and 594 cancer-free controls in the Chinese Han population, using matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectroscopy. The pooled odds ratio was 1.42 (95% confidence interval [CI]=1.01-1.99, p=0.042) for carriers with the A version of the allele (AA and AG) compared with GG, and 1.46 (95% CI=1.02-2.09, p=0.036) for AG compared with GG. Our data provide evidence that the rs1412115: A>G polymorphism increases the risk of OSCC in Chinese Han populations. Larger population-based studies are needed to confirm these results.

Endothelial interleukin-6 defines the tumorigenic potential of primary human cancer stem cells

Head and neck squamous cell carcinomas (HNSCC) contain a small subpopulation of stem cells endowed with unique capacity to generate tumors. These cancer stem cells (CSC) are localized in perivascular niches and rely on crosstalk with endothelial cells for survival and self-renewal, but the mechanisms involved are unknown. Here, we report that stromal interleukin (IL)-6 defines the tumorigenic capacity of CSC sorted from primary human HNSCC and transplanted into mice. In search for the cellular source of Interleukin-6 (IL-6), we observed a direct correlation between IL-6 levels in tumor-associated endothelial cells and the tumorigenicity of CSC. In vitro, endothelial cell-IL-6 enhanced orosphere formation, p-STAT3 activation, survival, and self-renewal of human CSC. Notably, a humanized anti-IL-6R antibody (tocilizumab) inhibited primary human CSC-mediated tumor initiation. Collectively, these data demonstrate that endothelial cell-secreted IL-6 defines the tumorigenic potential of CSC, and suggest that HNSCC patients might benefit from therapeutic inhibition of IL-6/IL-6R signaling.

Serum CCL2 and CCL3 as potential biomarkers for the diagnosis of oral squamous cell carcinoma

Monocyte chemotactic protein-1 (MCP-1/CCL2) and macrophage inflammatory protein-1α (MIP-1α/CCL3) are small chemotactic proteins that have been found in several kinds of tumor tissue samples and function as key regulators of cancer progression. However, the expression of CCL2 and CCL3 in serum samples of oral squamous cell carcinoma (OSCC) patients remains unknown. This study aimed to investigate the prognostic meaning of serum CCL2 and CCL3 in OSCC. The concentration of CCL2 and CCL3 was assessed by ELISA in serum of OSCC patients (n = 98), leukoplakia patients (n = 14), and healthy donors (n = 27). The results showed that the concentration of CCL2 in the OSCC group was significantly lower compared to that in the healthy controls (67.81 vs. 108.1 pg/ml, P < 0.0001). The CCL3 concentration was higher in leukoplakia patients than in OSCC patients and healthy donors (201.9 vs. 153.9 or 118.3 pg/ml, P < 0.05). No significant difference in CCL3 concentration was observed between OSCC patients and healthy donors. However, the OSCC group clearly presented two subclusters, i.e., CCL3 (LOW) and CCL3 (HIGH) OSCC subclusters, in which the serum level of CCL3 was positively related to the tumor size. Interestingly, the ratio of CCL2/CCL3 in OSCC patients was correlated to TNM (tumor, node, metastasis), smoking habits, and differentiation. The receiver operating characteristic (ROC) curve suggests that serum CCL2 is a good diagnostic marker to discriminate OSCC patients from healthy people (cutoff value, 101.1 pg/ml) and the ratio of CCL2/CCL3 also is a good diagnostic marker to discriminate leukoplakia patients and CCL3 (HIGH) OSCC patients from healthy people (cutoff values, 1.080 and 0.424, respectively). These results indicate that CCL2 and CCL3 are associated with progression of OSCC and may be potential biomarkers.

The expression of activin receptor-like kinase 1 among patients with head and neck cancer

OBJECTIVES

We investigated the expression and clinical significance of activin receptor-like kinase 1 (ACVRL1) in patients with head and neck squamous cell carcinoma (HNSCC).

STUDY DESIGN

Case series with chart review.

SETTING

Academic Institute of Otolaryngology, Kaohsiung, Taiwan.

SUBJECTS AND METHODS

Patients diagnosed with HNSCC (n = 169) underwent surgical resection followed by radiotherapy and/or chemotherapy for aggressive tumors between November 2000 and March 2004. ACVRL1 expression was assessed using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry approaches.

RESULTS

High levels of ACVRL1 expression were significantly correlated with advanced T classification (P < .001), positive N classification (P = .002), advanced TNM stage (P < .001), lymphovascular invasion (P < .001), and extracapsular spread of lymph node metastasis (P = .021). A poor 5-year overall survival rate was correlated with high ACVRL1 expression (P = .0048), advanced T classification (P = .0075), positive N classification (P = .0024), advanced TNM stage (P = .0077), and extracapsular spread of lymph node (P = .0002), but a multivariate analysis using the Cox regression model revealed that the only independent prognostic factors for survival were ACVRL1 expression (P = .043; odds ratio [OR], 1.635; 95% confidence interval [CI], 1.017-2.629) and extracapsular spread of lymph node metastasis (P = .003; OR, 2.052; 95% CI, 1.270-3.315).

CONCLUSION

A high level of ACVRL1 expression in tumor tissue is significantly correlated with advanced T classification, positive N classification, advanced TNM stage, and poorer prognosis.

Quercetin suppresses drug-resistant spheres via the p38 MAPK-Hsp27 apoptotic pathway in oral cancer cells

Background

Treatment failure in oral squamous cell carcinoma (OSCC) leading to local recurrence(s) and metastases is mainly due to drug resistance. Cancer stem cells (CSCs) are thought be responsible for the development of drug resistance. However, the correlations between CSCs, drug resistance, and new strategy against drug resistance in OSCC remain elusive.

Methods

A drug-resistant sphere (DRSP) model was generated by using a nonadhesive culture system to induce drug-resistant cells from SCC25 oral cancer cells. A comparative analysis was performed between the parent control cells and DRSPs with a related treatment strategy focusing on the expression of epithelial–mesenchymal transition (EMT)-associated markers, drug-resistance-related genes, and CSC properties in vitro, as well as tumorigenicity and the regimen for tumor regression in vivo.

Results

Our data show the presence of a phenomenon of EMT with gradual cellular transition from an epithelioid to mesenchymal-like spheroid morphology during induction of drug resistance. The characterization of DRSPs revealed the upregulation of the drug-resistance-related genes ABCG2 and MDR-1 and of CSC-representative markers, suggesting that DRSPs have greater resistance to cisplatin (Cis) and stronger CSC properties compared with the control. Moreover, overexpression of phosphorylated heat-shock protein 27 (p-Hsp27) via the activation of p38 MAPK signaling was observed in DRSPs. Knockdown of Hsp27 decreased Cis resistance and induced apoptosis in DRSPs. Furthermore, an inhibitor of Hsp27, quercetin (Qu), suppressed p-Hsp27 expression, with alterations of the EMT signature, leading to the promotion of apoptosis in DRSPs. A xenographic study also confirmed the increase of tumorigenicity in DRSPs. The combination of Qu and Cis can reduce tumor growth and decrease drug resistance in OSCC.

Conclusions

The p38 MAPK–Hsp27 axis plays an important role in CSCs-mediated drug resistance in OSCC. Targeting this axis using Qu combined with Cis may be a treatment strategy to improve prognosis in patients with OSCC.

The expression and prognostic significance of hepatoma-derived growth factor in oral cancer

Hepatoma-derived growth factor (HDGF) participates in oncogenic progression and represents a prognostic factor in several types of cancer. This study aimed to elucidate the role of HDGF during oral carcinogenesis. HDGF expression and the tumorigenic behaviors in human oral cell lines were investigated by immunoblotting, invasion and colony formation assays. Recombinant adenovirus vectors were employed to modulate the HDGF level in oral cancer cells. Immunohistochemical analysis using tissue microarray (TMA) consisting of surgically resected samples from 95 oral cancer patients was performed to delineate the correlation between HDGF expression and clinic-pathological parameters. HDGF expression was higher in malignant oral cancer cells than benign ones. Adenovirus-mediated HDGF overexpression and knockdown demonstrated the cellular HDGF level regulated the tumorigenic behaviors of oral cancer cells. Immunohistochemical analysis revealed increased HDGF expression in the nucleus and cytoplasm in oral cancer tissues. The nuclear HDGF expression was significantly correlated with tumor stage (P=0.004) and grade (P=0.013) while the cytoplasmic HDGF expression was associated with tumor necrosis (P=0.002). Kaplan-Meier analysis revealed that patients with high nuclear HDGF expression had significantly worse 5-year disease-specific survival (P=0.0069), metastasis-free survival (P=0.0168), and local recurrence-free survival (P=0.0047). Multivariate analysis indicated that the nuclear HDGF labeling index was an independent prognostic factor for disease-specific and local recurrence-free survival. HDGF overexpression contributes to the oncogenic processes in oral cancer cells and constitutes a novel prognostic factor for survival outcome of oral cancer patients.

Identification of antiplatelet and acetylcholinesterase inhibitory constituents in betel nut

OBJECTIVE

To investigate the possible mechanism and the compound(s) responsible for the antiplatelet and acetylcholinesterase (AChE) inhibitory effects of Areca catechu crude extract (Ac.Cr).

METHODS

Aqueous-methanol (70%) was used for extraction of plant material (betel nut). Antiplatelet activity was measured in human platelet-rich plasma by using a Lumi-aggregometer while anti-AChE activity was measured spectrophotometrically in vitro. In an attempt to find the responsible compound(s) in betel nut for antiplatelet and anti-AChE activities, different commercially available betel nut compounds were tested.

RESULTS

Ac.Cr inhibited platelet aggregation induced by arachidonic acid (AA), adenosine diphosphate (ADP), platelet-activating factor (PAF), epinephrine and Ca(2+)-ionophore. Ac.Cr was the most potent in inhibiting ADP- and Ca(2+)-ionophore-induced aggregation. In the AChE assay, Ac.Cr showed significant AChE inhibitory activity with almost complete inhibition of the enzyme. Out of the tested compounds, none of the compounds in betel nut showed any antiplatelet effect except for catechin that was the most potent against epinephrine-induced aggregation. Catechin was significantly less potent than Ac.Cr, indicating a presence of additional compound(s) with antiplatelet activity. For the AChE inhibitory effect, only tannic acid, gallic acid, diosgenin and isoguvacine were found to be active, whereby tannic acid was more potent than Ac.Cr.

CONCLUSION

This study shows the possible antiplatelet and AChE inhibitory potential of betel nut while further studies are needed to confirm and identify more compounds in betel nut for these actions.

Nonadhesive culture system as a model of rapid sphere formation with cancer stem cell properties

Background

Cancer stem cells (CSCs) play an important role in tumor initiation, progression, and metastasis and are responsible for high therapeutic failure rates. Identification and characterization of CSC are crucial for facilitating the monitoring, therapy, or prevention of cancer. Great efforts have been paid to develop a more effective methodology. Nevertheless, the ideal model for CSC research is still evolving. In this study, we created a nonadhesive culture system to enrich CSCs from human oral squamous cell carcinoma cell lines with sphere formation and to characterize their CSC properties further.

Methods

A nonadhesive culture system was designed to generate spheres from the SAS and OECM-1 cell lines. A subsequent investigation of their CSC properties, including stemness, self-renewal, and chemo- and radioresistance in vitro, as well as tumor initiation capacity in vivo, was also performed.

Results

Spheres were formed cost-effectively and time-efficiently within 5 to 7 days. Moreover, we proved that these spheres expressed putative stem cell markers and exhibited chemoradiotherapeutic resistance, in addition to tumor-initiating and self-renewal capabilities.

Conclusions

Using this nonadhesive culture system, we successfully established a rapid and cost-effective model that exhibits the characteristics of CSCs and can be used in cancer research.

The effect of CCND1 +870A>G and VEGF +936C>T polymorphisms on oral cancer development and disease-free survival in a Taiwan population

The association between polymorphisms in vascular endothelial growth factor (VEGF) +936C>T and cyclin D1 (CCND1) +870A>G genes, oral cancer risk, and disease-free survival remains controversial. We found no association between polymorphisms in the CCND1 and VEGF genes and oral cancer development using multivariate logistic regression analysis. Clinical data indicated that the VEGF +936C>T polymorphisms were associated with larger tumor size and advanced cancer stage, but the χ(2) test did not show that CCND1 polymorphisms were associated with larger tumor size and advanced cancer stage. However, Cox proportional hazards model analysis showed no correlation between the VEGF +936C>T polymorphisms and poor disease-free survival. The CCND1 +870A>G polymorphisms (hazard ratio (HR)=1.62, 95% CI=1.10-2.46; adjusted HR=1.63, 95% CI=1.08-2.54) and larger tumor size were associated with poor 5-year disease-free survival by the log rank test and multivariate Cox proportional hazards model analysis. We hypothesized that polymorphisms in CCND1 +870A>G and VEGF +936C>T genes are not correlated with the development of oral cancer. We found the CCND1 +870G allele to be an independent risk factor for poor 5-year disease-free survival in oral cancer patients. VEGF +936C>T polymorphisms were not directly correlated with poor survival, but they might be associated with increased tumor size, which affected our disease-free survival results.

The role of CXCR2 chemokine receptors in the oral squamous cell carcinoma

This study evaluated the relevance of CXCR2 chemokine receptors in oral squamous cell carcinoma, by means of in vitro and in vivo approaches. The in vitro incubation of the selective and non-peptide CXCR2 receptor antagonist N-(2-hydroxy-4-nitrophenyl)-N9-(2-bromophenyl) Urea (SB225002; 25 to 800 nM) produced a time- and concentration-dependent inhibition of SCC158 (rat) and HN30 (human) cell lines viability. Conversely, this antagonist did not significantly affect the viability of the immortalized keratinocyte lineage, HaCaT. Additionally, the incubation of human IL-8 and rat CINC-1 CXCR2 agonists produced a concentration-related increase on HN30 and SCC158 proliferation. The submucosal injection of SCC158 cells (5 × 10(6) cells) into the tongue of Fischer 344 rats induced tumor development, which displayed typical clinical features. Immunohistochemical analysis of rat tongue biopsies revealed a marked increase of CXCR2 receptor immunoreactivity, which was accompanied by augumented expression of VEGF and caspase-3. Our data suggests an important role for CXCR2 receptors in oral squamous cell carcinoma.

Markedly increased Oct4 and Nanog expression correlates with cisplatin resistance in oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) is the sixth most prevalent cancer worldwide. Cancer stem cells (CSC) model theoretically contribute to tumor growth, metastasis, and chemo-radioresistance. Cisplatin is a widely used chemotherapeutic agent for OSCC treatment. The aim of this study was to compare stemness genes expression in chemo-sensitive and chemo-resistant specimens and further explore the potential markers that may lead to induce chemo-resistance in OSCC.

METHODS

The study method is the treatment of OC2 cells with cisplatin select cisplatin-resistant OC2 cells. Self-renewal ability was evaluated by cultivating parental and cisplatin-resistant OC2 cells within sphere-forming assay after serial passages. Differential expression profile of stemness markers between parental and cisplatin-resistant OC2 cells was elucidated. The parental and cisplatin-resistant OC2 cells were assessed for migration/invasion/clonogenicity tumorigenic properties in vitro. Expression of stemness markers in chemo-sensitive and chemo-resistant patients with OSCC was performed by immunohistochemistry staining in vivo.

RESULTS

Sphere-forming/self-renewal capability was increased in cisplatin-resistant OC2 cells. Cisplatin-resistant OC2 cells highly expressed the stemness markers (Nanog, Oct4, Bmi1, CD117, CD133, and ABCG2). Furthermore, cisplatin-resistant OC2 cells increased migration/invasion/clonogenicity ability. Notably, up-regulation of Oct4 and Nanog expression was significantly observed in cisplatin-resistant patients with OSCC (**P < 0.01).

CONCLUSIONS

These data indicate that cancer stem-like properties were expanded during the acquisition of cisplatin resistance in OSCC. Clinically, oral cancer stemness markers (Oct4 and Nanog) overexpression may promote the OSCC's recurrence to resist cisplatin.

Cucurbitacin I suppressed stem-like property and enhanced radiation-induced apoptosis in head and neck squamous carcinoma--derived CD44(+)ALDH1(+) cells

Head and neck squamous cell carcinoma (HNSCC) is a prevalent cancer worldwide. Signal transducers and activators of transcription 3 (STAT3) signaling is reported to promote tumor malignancy and recurrence in HNSCC. Cucurbitacins, triterpenoid derivatives, are strong STAT3 inhibitors with anticancer properties. Recent studies have shown aldehyde dehydrogenase 1 (ALDH1) to be a marker of cancer stem cells (CSC) in HNSCC. The aim of this study was to investigate the therapeutic effect of cucurbitacin I in HNSCC-derived CSCs. Using immunohistochemical analysis, we firstly showed that CD44, ALDH1, and phosphorylated STAT3 (p-STAT3) were higher in high-grade HNSCCs, and that triple positivity for CD44/ALDH1/p-STAT3 indicated a worse prognosis for HNSCC patients. Secondly, CD44(+)ALDH1(+) cells isolated from seven HNSCC patients showed greater tumorigenicity, radioresistance, and high expression of stemness (Bmi-1/Oct-4/Nanog) and epithelial-mesenchymal-transitional (Snail/Twist) genes as p-STAT3 level increased. Furthermore, we found that cucurbitacin I (JSI-124) can effectively inhibit the expression of p-STAT3 and capacities for tumorigenicity, sphere formation, and radioresistance in HNSCC-CD44(+)ALDH1(+). Notably, 150 nmol/L cucurbitacin I effectively blocked STAT3 signaling and downstream survivin and Bcl-2 expression, and it induced apoptosis in HNSCC-CD44(+)ALDH1(+). Moreover, microarray data indicated that 100 nmol/L cucurbitacin I facilitated CD44(+)ALDH1(+) cells to differentiate into CD44⁻ALDH1⁻ and enhanced the radiosensitivity of HNSCC-CD44(+)ALDH1(+). Xenotransplant experiments revealed that cucurbitacin I combined with radiotherapy significantly suppressed tumorigenesis and lung metastasis and further improved the survival rate in HNSCC-CD44(+)ALDH1(+)-transplanted immunocompromised mice. Taken together, our data show that cucurbitacin I, STAT3 inhibitor, reduces radioresistant, distant-metastatic, and CSC-like properties of HNSCC-CD44(+)ALDH1(+) cells. The potential of cucurbitacin I as a radiosensitizer should be verified in future anti-CSC therapy.

Pro-inflammatory genes as biomarkers and therapeutic targets in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a major health problem worldwide, and patients have a particularly poor 5-year survival rate. Thus, identification of the molecular targets in OSCC and subsequent innovative therapies are greatly needed. Prolonged exposure to alcohol, tobacco, and pathogenic agents are known risk factors and have suggested that chronic inflammation may represent a potential common denominator in the development of OSCC. Microarray analysis of gene expression in OSCC cell lines with high basal NF-κB activity and OSCC patient samples identified dysregulation of many genes involved in inflammation, wound healing, angiogenesis, and growth regulation. In particular IL-8, CCL5, STAT1, and VEGF gene expression was up-regulated in OSCC. Moreover, IL-8 protein levels were significantly higher in OSCC cell lines as compared with normal human oral keratinocytes. Targeting IL-8 expression by siRNA significantly reduced the survival of OSCC cells, indicating that it plays an important role in OSCC development and/or progression. Inhibiting the inflammatory pathway by aspirin and the proteasome/NF-κB pathway by bortezomib resulted in marked reduction in cell viability in OSCC lines. Taken together our studies indicate a strong link between inflammation and OSCC development and reveal IL-8 as a potential mediator. Treatment based on prevention of general inflammation and/or the NF-κB pathway shows promise in OSCCs.