The upregulation of heat shock protein 70 expression in areca quid chewing-associated oral squamous cell carcinomas

High Expression of Tomm34 and Its Correlations With Clinicopathology in Oral Squamous Cell Carcinoma

Tomm34, as a member of the outer mitochondrial membrane proteins, is evenly distributed between the cytoplasm and the outer mitochondrial membrane. It is up-regulated in a variety of tumors and correlates with poor prognosis. This study aimed to investigate expression of Tomm34 and its correlations with clinicopathology in oral squamous cell carcinoma (OSCC). Oncomine database and UALCAN database were utilized to predict the expression and prognosis values of Tomm34 in head and neck squamous cell carcinoma (HNSCC). By immunohistochemistry, a retrospective study was performed to verify the bioinformatics results to evaluate the Tomm34 expression and clinicopathological variables in both HPV-positive OSCC and HPV-negative OSCC. Immunohistochemistry of our cohort revealed that 48 cases fulfilled the Tomm34 high expression judgment criteria, and the overall positive rate was 60% (48/80), and 27 cases fulfilled the p16 expression judgment criteria (33.75%, 27/80). The high expression of Tomm34 was closely related with the TNM classification of OSCC (p < 0.01) and tumor size (p < 0.01) both in HPV-negative OSCC and HPV-positive OSCC, while related with lymph node metastasis (p = 0.001) in HPV-negative OSCC and drinking history (p = 0.044) in HPV-positive OSCC. In addition, the Kaplan-Meier curves indicated that higher level of Tomm34 was correlated with poorer overall survival (OS) and disease-free survival (DFS) in HPV-negative OSCC (OS, p = 0.046; DFS, p = 0.020) but not in HPV-positive OSCC (OS, p = 0.824; DFS, p = 0.782). In conclusion, Tomm34 is highly expressed in OSCC and may be a useful factor to provide prognostic information, especially in HPV-negative OSCC group.

2-phenylethynesulfonamide inhibits growth of oral squamous cell carcinoma cells by blocking the function of heat shock protein 70

Oral squamous cell carcinoma (OSCC) is the most common malignancy in the oral cavity, which accounts for >90% of all diagnosed oral cancers. 2-phenylethynesulfonamide (PES) was known as a selective heat shock protein 70 (Hsp70) function inhibitor, which induced cytotoxic effects on various tumor cell types, but showed to be less toxic to normal cells. However, no associated evaluation of PES on OSCC was found. In the present study, the proliferation of OSCC cells treated with PES was analyzed using a CCK-8 assay. The effects of PES on the cell cycle and apoptosis of OSCC cells were determined by flow cytometric analyses. Expression of associated protein was determined by Western blot analysis. The results of the present study showed that PES inhibited the proliferation of OSCC cell lines in vivo and in vitro. PES induced apoptosis and arrested the cell cycle of OSCC cells. PES inhibited the expression of X-linked inhibitor of apoptosis protein (XIAP), baculoviral IAP repeat containing 2 (c-IAP1), phosphorylated AKT (p-AKT), and phosphorylated extracellular signal-regulated kinase (p-ERK). Additionally, knockdown of Hsp70 enhanced the effects of PES. By contrast, overexpression of Hsp70 attenuated the inhibitory effects of PES on cell viability. PES disrupted the interaction between Hsp70 and XIAP. In conclusion, the present study demonstrated that PES suppresses the growth of OSCC cells through Hsp70-dependent mechanism.

Potential Role of Curcumin and Its Nanoformulations to Treat Various Types of Cancers

Cancer is a major burden of disease globally. Each year, tens of millions of people are diagnosed with cancer worldwide, and more than half of the patients eventually die from it. Significant advances have been noticed in cancer treatment, but the mortality and incidence rates of cancers are still high. Thus, there is a growing research interest in developing more effective and less toxic cancer treatment approaches. Curcumin (CUR), the major active component of turmeric (Curcuma longa L.), has gained great research interest as an antioxidant, anticancer, and anti-inflammatory agent. This natural compound shows its anticancer effect through several pathways including interfering with multiple cellular mechanisms and inhibiting/inducing the generation of multiple cytokines, enzymes, or growth factors including IκB kinase β (IκKβ), tumor necrosis factor-alpha (TNF-α), signal transducer, and activator of transcription 3 (STAT3), cyclooxygenase II (COX-2), protein kinase D1 (PKD1), nuclear factor-kappa B (NF-κB), epidermal growth factor, and mitogen-activated protein kinase (MAPK). Interestingly, the anticancer activity of CUR has been limited primarily due to its poor water solubility, which can lead to low chemical stability, low oral bioavailability, and low cellular uptake. Delivering drugs at a controlled rate, slow delivery, and targeted delivery are other very attractive methods and have been pursued vigorously. Multiple CUR nanoformulations have also been developed so far to ameliorate solubility and bioavailability of CUR and to provide protection to CUR against hydrolysis inactivation. In this review, we have summarized the anticancer activity of CUR against several cancers, for example, gastrointestinal, head and neck, brain, pancreatic, colorectal, breast, and prostate cancers. In addition, we have also focused on the findings obtained from multiple experimental and clinical studies regarding the anticancer effect of CUR in animal models, human subjects, and cancer cell lines.

Prognosis and predictive value of heat-shock proteins expression in oral cancer: A PRISMA-compliant meta-analysis

BACKGROUND

Heat-shock proteins (HSP) is a key chaperone protein which maintains intracellular proteostasis and is expressed on the surface of solid and hematological malignancies. Several studies have reported paradoxical evidence of the association between HSP expression and prognosis of oral cancer. To address the discrepancy, we carried out the meta-analysis to assess the role of HSP such as: HSP70, HSP90, HSP27, HSP60, and HSP105 in susceptibility, progression, and prognosis of oral cancer.

MATERIALS AND METHODS

We retrieved the PubMed, Embase, Web of science, China National Knowledge Infrastructure (CNKI), and Wanfang databases to acquire the eligible studies which were associated with HSP70, HSP90, HSP27, HSP60, and HSP105 protein expression and oral cancer. We applied hazard ratio (HR) and its 95% confidence interval (95% CI) to assess the value of HSP protein expression in overall survival of oral cancer; odds ratio (OR) and its 95% CI were used to evaluate the association of risk and clinical features of oral cancer. Funnel plot, Begg test, and Egger line regression test were utilized to observe publication bias among studies. All statistical analysis was performed with Stata 14.0 software (Stata Corporation, College Station, TX).

RESULTS

A total of 26 studies were included in the present meta-analysis. On based of the results, HSP70 and HSP27 had no significant association with progression of oral cancer. However, the pooled HR and 95% CI revealed a significant well effects of HSP70 and HSP27 expression on survival of oral cancer. Moreover, the susceptibility of oral cancer was significantly associated with HSP70 and HSP60 overexpression.

CONCLUSION

HSP70 and HSP27 protein overexpression might be valuable biomarkers for the prognosis of oral cancer. And HSP70 and HSP60 might have potential predictive effects on the risk of oral cancer.

Demographic study of 366 cases of oral leukoplakia and immunohistochemical analysis – An institutional study

Background:

It has been reported that oral squamous cell carcinoma (OSCC) is associated with the presence of potentially malignant disorders (PMDs) in 15%–48% of cases. Among PMDs, oral leukoplakia (OL) is the most common, with 16%–62% of cases associated with OSCC. Hence, in the present study, we have analyzed demographic data and re-evaluated immunohistochemical (IHC) data of OL cases and aimed to correlate the clinical, histopathological and IHC aspects of OL.

Materials and Methods:

The data of histopathologically diagnosed cases of OL were retrieved from the archives. These data were further evaluated for age, gender, duration, site, size, side, habits, clinical staging and histopathological grading. IHC re-evaluation of OL tissues was done using epithelial cadherin (E-cadherin), n = 20; human MutL homolog 1 (hMLH1), n = 30; CD1a (n = 30); vimentin (n = 30); Ki-67 (n = 30); heat shock protein-70 (HSP-70), n = 30; p16^INK4, n = 20; and mucin-1 (MUC1), n = 30. All the results and observations were subjected to descriptive statistical analysis.

Results:

The male: female ratio was 7.5:1; right side and buccal mucosa were more commonly affected. The duration of the lesion ranged from 1 to 30 years. One hundred and twelve patients were habituated to tobacco chewing, while 171 patients came with a combined habit of smoke and smokeless tobacco usage. Clinically, most of the lesions were of stage 2 while histopathologically they were of mild dysplasia. There was a decrease in the immunoexpression of E-cadherin, hMLH1 and CD1a, while there was an increase in the immunoexpression of vimentin, Ki-67, HSP-70, MUC1 and p16^INK4.

Conclusion:

The study of different biomarkers such as cytoplasmic, membranous and nuclear in OL will help in better understanding and application of a reliable marker for diagnostic and prognostic purpose.

A Review on Role of Arecoline and Its Metabolites in the Molecular Pathogenesis of Oral Lesions with an Insight into Current Status of Its Metabolomics

Areca nut consumption is a popular habit in Southeast Asian countries. One of the important biologically active alkaloids of areca nut is arecoline, which plays a role in mediating the development of several pathologies of the primary exposure site, the oral cavity. Studies on the metabolism of arecoline revealed the formation of several metabolites which themselves might be toxic. Moreover, polymorphisms in genes encoding enzymes involved in the metabolism of arecoline might predispose an organism towards the development of oral cancer. The present review tries to accumulate all the relevant existing literature and then elucidate the molecular mechanism by which arecoline plays a role in the development of oral submucous fibrosis and oral cancer. Existing information regarding arecoline metabolism, enzymes involved in the metabolic process and biological effects of the metabolites of arecoline have also been compiled and compared to study the toxicity of metabolites with its parent compound arecoline and whether they play any role in the pathogenesis of oral cancer mediated by areca nut consumption. A repertoire of molecular targets has come up in the discussion whose expression profile is perturbed by arecoline. Construction of induction cascade from existing literature has given an idea about the process of molecular pathogenesis. The summarized and analysed data can help to determine the molecular mechanism and drug targets, which in turn could be helpful in the prevention or treatment of these pathological conditions. It also brings into light areas where further research needs to be directed.

A genetic programming approach to oral cancer prognosis

Background

The potential of genetic programming (GP) on various fields has been attained in recent years. In bio-medical field, many researches in GP are focused on the recognition of cancerous cells and also on gene expression profiling data. In this research, the aim is to study the performance of GP on the survival prediction of a small sample size of oral cancer prognosis dataset, which is the first study in the field of oral cancer prognosis.

Method

GP is applied on an oral cancer dataset that contains 31 cases collected from the Malaysia Oral Cancer Database and Tissue Bank System (MOCDTBS). The feature subsets that is automatically selected through GP were noted and the influences of this subset on the results of GP were recorded. In addition, a comparison between the GP performance and that of the Support Vector Machine (SVM) and logistic regression (LR) are also done in order to verify the predictive capabilities of the GP.

Result

The result shows that GP performed the best (average accuracy of 83.87% and average AUROC of 0.8341) when the features selected are smoking, drinking, chewing, histological differentiation of SCC, and oncogene p63. In addition, based on the comparison results, we found that the GP outperformed the SVM and LR in oral cancer prognosis.

Discussion

Some of the features in the dataset are found to be statistically co-related. This is because the accuracy of the GP prediction drops when one of the feature in the best feature subset is excluded. Thus, GP provides an automatic feature selection function, which chooses features that are highly correlated to the prognosis of oral cancer. This makes GP an ideal prediction model for cancer clinical and genomic data that can be used to aid physicians in their decision making stage of diagnosis or prognosis.

Knockdown of S100A4 impairs arecoline-induced invasiveness of oral squamous cell carcinomas

OBJECTIVES

Metastasis is the most common cause of oral squamous cell carcinoma (OSCC)-related death. The physiological function of S100A4 in the pathogenesis of areca quid chewing-associated OSCC has not been uncovered.

METHOD

OSCC tissues from areca quid chewers were analyzed by immunohistochemistry for S100A4 expression. The functions of S100A4 in invasiveness of arecoline-treated oral epithelial (OE) cells were determined by loss function approaches.

RESULTS

Expression of S100A4 was positively correlated with clinical grading and lymph node metastasis of OSCC. Upregulated S100A4 is correlated with poor survival outcome of OSCC patients. Arecoline led to dose-dependent elevation of S100A4 expression in oral epithelial (OE) cells. Down-regulation of S100A4 significantly reversed arecoline-induced oncogenecity in OE cells. The additions of pharmacological agents LY294002, SP600125, and CAY10585 were found to inhibit arecoline-induced S100A4 expression in OE cells.

CONCLUSION

Arecoline-induced S100A4 expression was down-regulated by LY294002, SP600125, or CAY10585 treatment. Targeting S100A4 might offer a new strategy for the treatment of OSCC patients with metastasis.

Sox2 expression involvement in the oncogenicity and radiochemoresistance of oral cancer stem cells

OBJECTIVES

Sox2, a high-mobility-group DNA binding protein, is part of the key set of transcription factors that are involved in the maintenance of pluripotency and self-renewal in undifferentiated stem cells. A recent study has further suggested cancer stem cells (CSCs) are key contributors to radiochemoresistance and are responsible for oral squamous cell carcinoma (OSCC) progression. The aim of this study was to determine the emerging role of Sox2 in radiochemosensitivity of oral CSCs.

METHODS

We determined the function of Sox2 on oncogenicity and radiochemosensitivity of OSCC by overexpression or silencing Sox2 in vitro and in vivo.

RESULTS

Initially, Sox2 expression was increased in OSCC cell lines and OSCC specimens. Upregulated Sox2 is correlated with poor survival outcome of OSCC patients. Overexpression of Sox2 was demonstrated to enhance invasiveness, anchorage-independent growth, xenotransplantation tumourigenicity in OSCC cells. Targeting Sox2 to spheroid cells (SC) and ALDH1+CD44+ cells from OSCC significantly inhibited their CSCs and tumorigenic abilities. Down regulation of SOX2 in OSCC-SC was found to repress invasiveness and diminish epithelail-mesenchymal transition (EMT) traits. Furthermore, silencing Sox2 effectively suppressed the expression of drug-resistance and anti-apoptotic genes and increased the sensitivity of the cells to radiation combined cisplatin treatment. Finally, the in vivo therapeutic efficacy of targeting Sox2 synergistically suppressed tumorigenesis and improved the survival rate when used in combination with radiotherapy and cisplatin in OSCC-SC-transplanted immunocompromised mice.

CONCLUSION

Sox2-mediated CSCs property is associated with the regulation of EMT and Sox2 s as therapeutic target in OSCC.

Expression of hypoxic signaling markers in head and neck squamous cell carcinoma and its clinical significance

Hypoxia is a consistent finding in fast-growing tumors; it contributes to tumor progression and therapeutic responses. We explored the expression of hypoxia-associated biomarkers in head and neck squamous cell carcinoma (HNSCC) to assess their relationship with clinical factors in HNSCC. In total, 90 patients with HNSCC were enrolled. Expression of HIF-1α, HSP70, HSP90, VEGF, IGF-1R, and P16 was investigated by immunohistochemistry. Their correlations with clinical factors, including location of primary sites, T stage, N stage, M stage, HPV status, primary treatment success/failure, recurrences, disease-free survival (DFS), and overall survival, were analyzed. HIF-1α, HPS70, HPS90, VEGF, and IGF-1R were positive in 33 of 89 (37.1 %), 62 of 87 (71.3 %), 83 of 89 (93.3 %), 41 of 87 (47.1 %), and 50 of 56 (89.3 %) cases, respectively. Expression levels of some of these markers were correlated. High HIF-1α or HSP 70 correlated with poor DFS, and expression of HSP70 correlated with LN metastasis. HPV-related carcinomas showed high HSP 70 and IGF-1R expression. Hypoxia-associated proteins were highly expressed and associated with aggressive clinical features in HNSCC. Expression of HIF-1α or HSP70 can be considered poor prognostic indicator in HNSCC. Our results suggest that hypoxic signaling is activated in HNSCC, especially in HPV-related tumors.

Oct4 mediates tumor initiating properties in oral squamous cell carcinomas through the regulation of epithelial-mesenchymal transition

BACKGROUND

Overexpression of Oct4, an important transcription factor of embryonic stem cells (ESC), has been reported in several cancers. The aim of this study was to determine the emerging role of Oct4 in oral squamous cell carcinoma (OSCC) both in vitro and in vivo.

METHODOLOGY/PRINCIPAL FINDING

Tumourigenic activity and molecular mechanisms of Oct4 overexpression or knockdown by lentiviral infection in OSCC was investigated in vitro and in vivo. Initially, we demonstrated that Oct4 expression was increased in OSCC cell lines as compared to a normal oral epithelial cell line SG. Overexpression of Oct4 was demonstrated to enhance cell proliferation, invasiveness, anchorage-independent growth and xenotransplantation tumourigenicity. These findings were coupled with epithelial-mesenchymal transition (EMT) transformation in OSCCs. In contrast, the silence of Oct4 significantly blocked the xenograft tumorigenesis of OSCC-derived cancer stem cells (OSCC-CSCs) and significantly improved the recipient survival. Clinically, the level of Oct4 expression was higher in recurrent and metastatic OSCC specimens but lower in primary OSCC specimens.

CONCLUSION/SIGNIFICANCE

Our results suggest that Oct4-mediated tumorigenecity is associated with the regulation of EMT. Oct4 might be a therapeutic target for OSCC.

Elevated snail expression mediates tumor progression in areca quid chewing-associated oral squamous cell carcinoma via reactive oxygen species

BACKGROUND

Snail is an important transcription factor implicated in several tumor progression and can be induced by reactive oxygen species (ROS). Areca quid chewing is a major risk factor of oral squamous cell carcinoma (OSCC). Therefore, we hypothesize that the major areca nut alkaloid arecoline may induce Snail via ROS and involve in the pathogenesis of areca quid chewing-associated OSCC.

METHODOLOGY/PRINCIPAL FINDING

Thirty-six OSCC and ten normal oral epithelium specimens were examined by immunohistochemistry and analyzed by the clinico-pathological profiles. Cytotoxicity, 2', 7'-dichlorofluorescein diacetate assay, and western blot were used to investigate the effects of arecoline in human oral keratinocytes (HOKs) and oral epithelial cell line OECM-1 cells. In addition, antioxidants N-acetyl-L-cysteine (NAC), curcumin, and epigallocatechin-3 gallate (EGCG) were added to find the possible regulatory mechanisms. Initially, Snail expression was significantly higher in OSCC specimens (p<0.05). Elevated Snail expression was associated with lymph node metastasis (p = 0.031) and poor differentiation (p = 0.017). Arecoline enhanced the generation of intracellular ROS at the concentration higher than 40 µg/ml (p<0.05). Arecoline was also found to induced Snail expression in a dose- and time-dependent manner (p<0.05). Treatment with NAC, curcumin, and EGCG markedly inhibited arecoline induced Snail expression (p<0.05).

CONCLUSION/SIGNIFICANCE

Our results suggest that Snail overexpression in areca quid chewing-associated OSCC is associated with tumors differentiation and lymph node metastasis. Arecoline-upregulated Snail expression may be mediated by ROS generation. In addition, arecoline induced Snail expression was downregulated by NAC, curcumin, and EGCG.

Quantum dot imaging for HSP70 and HSF‑1 kinetics in SCC‑25 cells with or without leucine deprivation following heat shock

The aim of this study was to develop a quantum dot-based approach for heat shock protein 70 (HSP70) and heat shock factor 1 (HSF-1) kinetics following heat shock, and to discover approaches to thermotherapy based on disrupting the effect of activation of HSF-1 and the accumulation of HSP70 by leucine deprivation. SCC-25 cells cultured with limiting leucine or normal leucine were stressed at 42˚C for 30 min, and were cultured for 2, 4, 6, 8 and 10 h, respectively. The expression of HSP70 and HSF-1 was observed using confocal laser microscopy and semi-quantitative analysis was performed by Image-Pro Plus. At 6 h after heating, HSF-1 in cells cultured with normal leucine was activated and translocated from the cytosol to the nucleus, and the synthesis of HSP70 reached the maximum value and had a tendency to gather in the nucleus. However, in cells cultured with limiting leucine, HSF-1 activity decreased and accumulation of HSP70 was not found. Leucine deprivation results in the inactivation of HSF-1 leading to slight accumulation of HSP70 and no tendency to gather in the nucleus. Thus, HSF-1 may serve as a novel therapeutic target in the treatment of oral cancer.

The expression of O(6) -methylguanine-DNA methyltransferase in human oral keratinocytes stimulated with arecoline

BACKGROUND

O(6) -methylguanine-DNA methyltransferase (MGMT) is a DNA repair enzyme that can protect cells from carcinogenic effects of alkylating agents by removing adducts from the O(6) position of guanine. Evidences indicated that areca quid chewing may increase the risk of oral squamous cell carcinoma (OSCC). This study was to investigate the role of MGMT expression in OSCCs and the normal oral tissues.

METHODS

Thirty-two OSCCs from areca quid chewers and ten normal oral tissue biopsy samples without areca quid chewing were analyzed by the immunohistochemistry for MGMT. Primary human oral keratinocytes (HOKs) were challenged with arecoline, the major alkaloid of areca nut, by Western blot. Nicotine, an important component of cigarette smoke, was added to find the possible regulatory mechanisms.

RESULTS

Significant association was observed between low MGMT expression and advanced clinical stage of OSCCs and lymph node metastasis (P = 0.03). MGMT expression was significantly higher in patients only chewing areca quid than patients both chewing areca quid and smoking (P = 0.028). Arecoline was found to elevate MGMT expression in a dose- and time-dependent manner. The addition of nicotine was found to enhance arecoline-induced MGMT expression.

CONCLUSION

Our results indicate that MGMT could be used clinically as a predictive marker for tumor processing, the potential for lymph node metastasis as well as advanced clinical stage. MGMT expression was significantly upregulated by arecoline in HOKs. Nicotine has a synergistic effect of arecoline-induced MGMT expression. The cigarette smoking may act synergistically in the pathogenesis of OSCC in areca quid chewers via the upregulation of MGMT.

HSP27 and HSP70 expression in squamous cell carcinoma: An immunohistochemical study

BACKGROUND

Heat shock proteins (HSPs) are a family of proteins that are known to play a significant role in the repair of denatured proteins in the cell. It seems that cytoprotective properties of HSPs may help in malignant progression by facilitating tumor cell growth and survival. The purpose of this study is to evaluate HSP27 and HSP70 expression in various histopathological grades of squamous cell carcinoma (SCC).

MATERIALS AND METHODS

In this retrospective-analytical study, the sections of 51 formalin-fixed paraffin-embedded biopsy specimens of SCC from various sites of oral and paraoral regions and 10 normal oral mucosa were immunostained by Novolink Polymer technique to determine the expression of HSP27 and HSP70. Then the data were analyzed according to the Kruskal-Walis, Mann-Whitney and the Spearman correlation tests (P<0.05).

RESULTS

The expression of HSP27 in well-differentiated SCC was significantly higher than normal epithelium (P=0.007) and in moderately differentiated SCC higher than poorly-differentiated SCC (P=0.023). Inverse correlation was observed between HSP27 expression and SCC's histopathological grade (P=0.001, r=-0.448). There was no significant difference between HSP70 staining of specimens (P=0.38).

CONCLUSIONS

The present study revealed that the expression level of HSP27 was inversely related to histopathological grade of SCC and it may provide prognostic value for patients with SCC, but there was no significant relationship between the expression of HSP70 and histopathological grades of SCC.

Regulation of protease-activated receptor-1 expression in human buccal fibroblasts stimulated with arecoline

BACKGROUND

The purpose of this study was to compare the major thrombin receptor protease-activated receptor-1 (PAR-1) expression in normal human buccal mucosa and oral submucous fibrosis (OSF) specimens and further explore the potential mechanisms that may lead to induce PAR-1 expression.

METHODS

Thirty OSF and 10 normal buccal mucosa specimens were examined by immunohistochemistry. Buccal mucosal fibroblasts (BMFs) were challenged with arecoline by using Western blot analysis. N-acetyl-L-cysteine (NAC), LY294002, herbimycin A, NS-398, and PD98059 were added to find the possible regulatory mechanisms.

RESULTS

PAR-1 expression was significantly higher in OSF specimens (p < .05). Arecoline was found to elevate PAR-1 expression in a dose-dependent and time-dependent manner (p < .05). The addition of NAC, LY294002, herbimycin A, NS398, and PD98059 markedly inhibited the arecoline-induced PAR-1 expression (p < .05).

CONCLUSION

PAR-1 expression is significantly upregulated in areca quid chewing-associated OSF. Arecoline-induced PAR-1 expression was downregulated by NAC, LY294002, herbimycin A, NS398, and PD98059.

Heat shock protein 27 expression in areca quid chewing-associated oral squamous cell carcinomas

OBJECTIVES

Heat shock protein (HSP) 27 is a low-molecular-weight protein that functions as a molecular chaperone and plays a cytoprotective role through its antioxidant activity during cell stress. Areca quid chewing is associated with the high incidence of oral squamous cell carcinomas (OSCCs) in Taiwan. The aim of this study was to compare heat shock protein 27 (HSP27) expression in OSCCs and the normal oral tissues.

METHODS

Forty-eight OSCCs from areca quid chewers and ten normal oral tissue biopsy samples without areca quid chewing were analyzed by immunohistochemistry for HSP27. The normal human oral keratinocytes (HOKs) were challenged with arecoline, the major alkaloid of areca nut, by Western blot for HSP27. Furthermore, epigallocatechin-3 gallate (EGCG), glutathione precursor N-acetyl-L-cysteine (NAC), cyclooxygenase-2 inhibitor NS-398, HSP inhibitor quercetin, extracellular signal-regulated protein kinase (ERK) inhibitor PD98059, and p38 inhibitor SB203580 were added to find the possible regulatory mechanisms.

RESULTS

Heat shock protein 27 exhibited higher expression in OSCCs than normal specimens (P < 0.05). Arecoline was found to elevate HSP27 expression in a dose- and time-dependent manner (P < 0.05). The additions of pharmacological agents were found to inhibit arecoline-induced HSP27 expression (P < 0.05).

CONCLUSIONS

Heat shock protein 27 expression is significantly elevated in areca quid chewing-associated OSCCs. Arecoline-induced HSP27 expression was downregulated by EGCG, NS398, NAC, quercetin, PD98059, and SB203580.

Therapeutic potential of curcumin in gastrointestinal diseases

Curcumin, also known as diferuloylmethane, is derived from the plant Curcuma longa and is the active ingredient of the spice turmeric. The therapeutic activities of curcumin for a wide variety of diseases such as diabetes, allergies, arthritis and other chronic and inflammatory diseases have been known for a long time. More recently, curcumin’s therapeutic potential for preventing and treating various cancers is being recognized. As curcumin’s therapeutic promise is being explored more systematically in various diseases, it has become clear that, due to its increased bioavailability in the gastrointestinal tract, curcumin may be particularly suited to be developed to treat gastrointestinal diseases. This review summarizes some of the current literature of curcumin’s anti-inflammatory, anti-oxidant and anti-cancer potential in inflammatory bowel diseases, hepatic fibrosis and gastrointestinal cancers.

Heat shock protein 47 expression in oral squamous cell carcinomas and upregulated by arecoline in human oral epithelial cells

BACKGROUND

Heat shock protein 47 (HSP47) is a product of CBP2 gene located at chromosome 11q13.5, a region frequently amplified in human cancers. Areca quid chewing is a major risk factor of oral squamous cell carcinoma (OSCC). The aim of this study was to compare HSP47 expression in normal human oral epithelium and OSCC and further to explore the potential mechanisms that may lead to induce HSP47 expression.

METHODS

Thirty-two OSCC specimens and ten normal oral tissue biopsy samples without areca quid chewing were analyzed by immunohistochemistry. The oral epithelial cell line OC2 cells were challenged with arecoline, a major areca nut alkaloid, by using Western blot analysis. Furthermore, glutathione precursor N-acetyl-l-cysteine (NAC), extracellular signal-regulated protein kinase (ERK) inhibitor PD98059, phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002, cyclooxygenase-2 inhibitor NS-398, and tyrosine kinase inhibitor herbimycin A were added to find the possible regulatory mechanisms.

RESULTS

HSP47 expression was significantly higher in OSCC specimens than normal epithelium (P<0.05). No significant difference in HSP47 expression was observed with respect to age, sex, T category, stage, and differentiation (P>0.05). The lower HSP47 expression was associated with lymph node metastasis (P=0.015). Arecoline was found to elevate HSP47 expression in a dose- and time-dependent manner (P<0.05). The addition of NAC, PD98059, LY294002, NS398, and herbimycin A markedly inhibited the arecoline-induced HSP47 expression (P<0.05).

CONCLUSION

  Our findings demonstrated that HSP47 expression is significantly upregulated in areca quid chewing-associated OSCCs. HSP47 could be used clinically as a marker for lymph node metastasis of oral carcinogenesis. In addition, arecoline-induced HSP47 expression was downregulated by NAC, PD98059, LY294002, NS398, and herbimycin A.

Hypoxia inducible factor-1α expression in areca quid chewing-associated oral squamous cell carcinomas

OBJECTIVES

Hypoxia inducible factor (HIF)-1α gene expression is mainly induced by tissue hypoxia. Overexpression of HIF-1α has been demonstrated in a variety of cancers. The aim of this study was to compare HIF-1α expression in normal human oral epithelium and areca quid chewing-associated oral squamous cell carcinoma (OSCC) and further to explore the potential mechanisms that may lead to induce HIF-1α expression.

METHODS

Twenty-five OSCC from areca quid chewing-associated OSCC and 10 normal oral tissue biopsy samples without areca quid chewing were analyzed by immunohistochemistry. The oral epithelial cell line GNM cells were challenged with arecoline, a major areca nut alkaloid, by using Western blot analysis. Furthermore, glutathione precursor N-acetyl-l-cysteine (NAC), AP-1 inhibitor curcumin, extracellular signal-regulated protein kinase inhibitor PD98059, and protein kinase C inhibitor staurosporine were added to find the possible regulatory mechanisms.

RESULTS

Hypoxia inducible factor-1α expression was significantly higher in OSCC specimens than normal specimen (P<0.05). Arecoline was found to elevate HIF-1α expression in a dose- and time-dependent manner (P<0.05). The addition of NAC, curcumin, PD98059, and staurosporine markedly inhibited the arecoline-induced HIF-1α expression (P<0.05).

CONCLUSIONS

Hypoxia inducible factor-1α expression is significantly upregulated in areca quid chewing-associated OSCC and HIF-1α expression induced by arecoline is downregulated by NAC, curcumin, PD98059, and staurosporine.

Analysis of differentially expressed proteins in oral squamous cell carcinoma by MALDI-TOF MS

PURPOSE

To explore the presence of differentially expressed proteins in OSCC for discrimination of tumour and normal mucosa to establish potential biomarkers and therapeutic targets.

EXPERIMENTAL DESIGN

Paired protein samples of 12 individuals (tongue cancer and non-cancerous mucosa) were separated by two-dimensional polyacrylamid gel electrophoresis. The protein patterns were compared pairwise and protein spots were quantified. We identified about 70 regulated proteins which we subsequently identified by MALDI-TOF mass spectrometry.

RESULTS

Cancerous and non-cancerous tissues could be most precisely distinguished by a panel of proteins. They include the heat shock proteins (hsp)70 and 90, keratins (ck) 5, 6, 13, 14, 16, 17 and 19, beta globin, alpha-2-actin, stratifin, tropomyosin, calreticulin precursor, beta-2-tubulin, galectin7, thioredoxin, involucrin, adenylyl-cyclase-associated protein, disulfide isomerase-associated protein, thyrosine 3-monooxygenase, MYL2 and the s100 calcium binding protein. MYL3, cardiac muscle alpha actin 1 proprotein and transferrin were under-represented in OSCC. Six biomarkers, ck6 und ck13, beta globin, alpha-2-actin, hsp70 and hsp90 discriminated best between cancerous and non-cancerous oral tissues. All over-expressed proteins were analysed by STRING-analysis to highlight experimentally determined and computationally predicted interactions between the proteins. Especially involucrin, hsp70, calreticulin precursor, stratifin, (ck) 5, 6, 14, 19, tyrosine 3-monooxygenase, beta-2-tubulin and disulfide isomerase associated protein showed multiple relations.

CONCLUSION

We identified six proteins which are differentially expressed in most OSCC compared to healthy tissues. Of those, by string analysis, multiple interaction partners are assumed for hsp70. This protein is supposed to be the most promising candidate as marker molecule and target for OSCC therapy.

Arecoline induced disruption of expression and localization of the tight junctional protein ZO-1 is dependent on the HER 2 expression in human endometrial Ishikawa cells

Background

Approximately 600 million people chew Betel nut, making this practice the fourth most popular oral habit in the world. Arecoline, the major alkaloid present in betel nut is one of the causative agents for precancerous lesions and several cancers of mouth among those who chew betel nut. Arecoline can be detected in the human embryonic tissue and is correlated to low birth weight of newborns whose mothers chew betel nut during pregnancy, suggesting that arecoline can induce many systemic effects. However, few reports exist as to the effects of arecoline in human tissues other than oral cancer cell lines. Furthermore, in any system, virtually nothing is known about the cellular effects of arecoline treatment on membrane associated signaling components of human cancer cells.

Results

Using the human Ishikawa endometrial cancer cell line, we investigated the effects of arecoline on expression, localization and functional connections between the ZO-1 tight junction protein and the HER2 EGF receptor family member. Treatment of Ishikawa cells with arecoline coordinately down-regulated expression of both ZO-1 and HER2 protein and transcripts in a dose dependent manner. Biochemical fractionation of cells as well as indirect immunofluorescence revealed that arecoline disrupted the localization of ZO-1 to the junctional complex at the cell periphery. Compared to control transfected cells, ectopic expression of exogenous HER2 prevented the arecoline mediated down-regulation of ZO-1 expression and restored the localization of ZO-1 to the cell periphery. Furthermore, treatment with dexamethasone, a synthetic glucocorticoid reported to up-regulate expression of HER2 in Ishikawa cells, precluded arecoline from down-regulating ZO-1 expression and disrupting ZO-1 localization.

Conclusion

Arecoline is known to induce precancerous lesions and cancer in the oral cavity of betel nut users. The arecoline down-regulation of ZO-1 expression and subcellular distribution suggests that arecoline potentially disrupts cell-cell interactions mediated by ZO-1, which may play a role in arecoline-mediated carcinogenesis. Furthermore, our study has uncovered the dependency of ZO-1 localization and expression on HER2 expression, which has therefore established a new cellular link between HER2 mediated signaling and apical junction formation involving ZO-1.

Impact of smoking and chewing tobacco on arsenic-induced skin lesions

BACKGROUND

We recently reported that the main reason for the documented higher prevalence of arsenic-related skin lesions among men than among women is the result of less efficient arsenic metabolism.

OBJECTIVE

Because smoking has been associated with less efficient arsenic methylation, we aimed to elucidate interactions between tobacco use and arsenic metabolism for the risk of developing skin lesions.

METHODS

We used a population-based case-referent study that showed increased risk for skin lesions in relation to chronic arsenic exposure via drinking water in Bangladesh and randomly selected 526 of the referents (random sample of inhabitants > 4 years old; 47% male) and all 504 cases (54% male) with arsenic-related skin lesions to measure arsenic metabolites [methylarsonic acid (MA) and dimethylarsinic acid (DMA)] in urine using high-performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICPMS).

RESULTS

The odds ratio for skin lesions was almost three times higher in the highest tertile of urinary %MA than in the lowest tertile. Men who smoked cigarettes and bidis (locally produced cigarettes; 33% of referents, 58% of cases) had a significantly higher risk for skin lesions than did nonsmoking men; this association decreased slightly after accounting for arsenic metabolism. Only two women smoked, but women who chewed tobacco (21% of referents, 43% of cases) had a considerably higher risk of skin lesions than did women who did not use tobacco. The odds ratio (OR) for women who chewed tobacco and who had < or = 7.9%MA was 3.8 [95% confidence interval (CI), 1.4-10] compared with women in the same MA tertile who did not use tobacco. In the highest tertile of %MA or %inorganic arsenic (iAs), women who chewed tobacco had ORs of 7.3 and 7.5, respectively, compared with women in the lowest tertiles who did not use tobacco.

CONCLUSION

The increased risk of arsenic-related skin lesions in male smokers compared with nonsmokers appears to be partly explained by impaired arsenic methylation, while there seemed to be an excess risk due to interaction between chewing tobacco and arsenic metabolism in women.