Ursolic acid-loaded chitosan nanoparticles suppress 7,12-dimethylbenz(a)anthracene-induced oral tumor formation through their antilipid peroxidative potential in golden Syrian hamsters.

Oral cancer, a disfiguring and life threatening cancer, significantly affects the day-to-day life of not only the patients but also their family members in terms of life quality and financial burden. India records higher incidence of oral cancer every year and is mainly due to the habituation of tobacco products and alcohol abuse. Delay in diagnosis and treatment influences India's higher incidence of oral cancer, where annually 50,000-60,000 oral carcinoma cases are reported. 7,12-dimethylbenz(a)anthracene (DMBA)-induced cancer in the oral cavity mimics human oral cancer in histopathological, molecular, and morphological aspects, and thus, by using this paradigm, the tumor inhibiting efficacy of medicinal plants or herbs and their components is scientifically validated. Ursolic acid, due to its multiple pharmacological effects, has been attracted, in recent years, for chemoprevention research program. Though, ursolic acid has been shown to have beneficial effects, its poor water solubility and bioavailability hinder to exert its 100% efficacy. Therefore, ursolic acid is encapsulated in either natural or synthetic polymers to enhance its therapeutic efficacy. Chitosan is one of the natural polymers that have been employed in the synthesis of nanoparticles to improve the drug efficacy. The present study has thus chosen ursolic acid-loaded chitosan nanoparticles (UACNP) to assess its anticancer efficacy in the DMBA-induced oral carcinoma. The anticancer efficacy of UACNP in experimental oral carcinogenesis was assessed by employing the status of oxidative markers and detoxification cascade as an end point. DMBA-induced abnormalities in the status of oxidative markers and detoxification cascade were reversed by ursolic acid-loaded chitosan nanoparticles. The tumor inhibiting or suppressing effect of UACNP is thus explored in experimental oral carcinogenesis.

Effect of ethanol extract from Chrysanthemum cinerariifolium leaves on Ki-67 proliferation and dysplasia severity in a rat model of oral squamous cell carcinoma.

Background: Oral squamous cell carcinoma (OSCC) is a malignant tumor that can rapidly infiltrate the oral epithelial tissue and cause high mortality worldwide because the available therapies are less effective. Chrysanthemum cinerariifolium leaf contains secondary metabolites as anti-inflammatory, antioxidant, anticancer, and antimutagenic. Aims: The study aimed to analyze the ethanolic extract of C. cinerariifolium leaf in reducing proliferation (Ki-67) and the degree of dysplasia in OSCC rats. Methods: This study used male Sprague Dawley induced by 7,12-dimethylbenz(a)anthracene (DMBA) 0.5% and divided into five treatment groups, namely positive control/C+ (sick), negative control/C- (healthy), and treatment group induced with DMBA and given extract C. cinerariifolium leaf with successive doses of T1, T2, and T3 (50, 100, and 200 mg/kg bw). The oral epithelium was stained with hematoxylin and eosin and immunohistochemically stained with a Ki-67 monoclonal antibody. The statistical analysis utilizes the one-way analysis of variance test. Results: The results showed that T1 at a dose of 200 mg/kg bw could significantly reduce Ki-67 expression and the degree of oral epithelial dysplasia (OED; p < 0.05) close to healthy controls. Conclusion: The conclusion shows that C. cinerariifolium leaf extract can be a therapy against OSCC by decreasing cell proliferation and the degree of OED.

Current Novel Drug Deliveries for Oral Cancer: A Chronotherapeutic Approach.

Oral squamous cell carcinoma is a malignant disease that is causing considerable mortality worldwide. Conventional treatment approaches, like surgery, cause destructive alterations in facial appearance and oral function impairments associated with psychological and social functioning. Chemotherapy exhibits low bioaccessibility of the anticancer drugs, multiple drug resistance, higher dose necessities, which elevate toxicities to the normal cells, low therapeutic index, and non-specific targeting. Radiation therapies significantly affect the well-being of the patient and impair the quality of life. Therefore, chemotherapeutics are developed that can either actively or passively target the carcinomas, reduce the adverse side effect, and improve therapeutic efficacy. Innovations in novel drug delivery systems deliver the drugs to the desired site of action with better treatment approaches with reduced toxicities to the normal cells and improve the health and survival rate of the patient. Cancer chronotherapy enhances the treatment proficiency by administration of the drugs at the best time, considering biological timings to improve the treatment profiles. Chronotherapy provides benefits to the current anticancer therapies, with minimum adverse effects to the healthy cells. This review discusses the risk factors for oral carcinomas, targeted therapy by nanocarriers, nanotechnology approaches, the role of circadian rhythm in the management of oral cancer, and advances in controlled drug delivery.

Oroxylum indicum Stem Bark Extract Reduces Tumor Progression by Inhibiting the EGFR-PI3K-AKT Pathway in an In Vivo 4NQO-Induced Oral Cancer Model.

OBJECTIVES: Oral squamous cell carcinoma (OSCC) is the predominant type of oral cancer. Its incidence is high in certain geographic regions, and it is correlated with chewing tobacco. Epidermal growth factor receptor (EGFR), induced by tobacco carcinogens, is overexpressed in OSCC, leading to poor prognosis. Thus, EGFR inhibitors are promising agents against OSCC. High cost and toxicity of existing EGFR inhibitors necessitate alternative EGFR-targeted therapy. Here, we tested the antitumor potential of ethyl acetate fraction of an ethnomedicinal tree, Oroxylum indicum stem bark extract (OIEA) in a 4-nitroquinoline-1-oxide (4NQO)-induced oral carcinogenesis model. METHODS: OIEA was prepared by solvent extraction method, and subsequently its in vitro radical scavenging activities were measured. High-performance liquid chromatography (HPLC) analysis of OIEA was done to identify the constituent active compounds. Hemolytic, trypan blue exclusion, and MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] assays were performed in normal and cancer cells to select an optimum dose of OIEA for antitumor activity study in 4NQO-induced oral cancer in F344 rats. Measurement of tumor volume, weight, and cell count was followed by tumor cell cycle analysis and comet and annexin V/Propidium Iodide (PI) assay. Pro-apoptotic markers were detected by western blot testing. Molecular docking was done to predict the interaction between OIEA active component and EGFR or phosphatidylinositol-3-kinase (PI3K), which was further validated biologically. Finally, hepatic and renal function testing and histopathology were performed. RESULTS: OIEA reduced tumor burden and increased survivability of the tumor-bearing rats significantly as compared to untreated tumor bearers. HPLC revealed oroxylin A as the predominant bioactive component in OIEA. Molecular docking predicted significant binding between oroxylin A and EGFR as well as PI3K, which was confirmed by western blot analysis of in vivo samples. OIEA also ameliorated hepato-, renal- and myelotoxicity induced by 4NQO. CONCLUSION: OIEA reduces 4NQO-induced OSCC by modulating the EGFR/PI3K/AKT signaling cascade and also ameliorated toxicity in tumor bearers.

Black Raspberry Extract Enhances Glutathione Conjugation of the Fjord-Region Diol Epoxide Derived from the Tobacco Carcinogen Dibenzo[def,p]chrysene in Human Oral Cells.

In a series of previous studies we reported that black raspberry (BRB) powder inhibits dibenzo[a,l]pyrene (DBP)-induced DNA damage, mutagenesis, and oral squamous cell carcinoma (OSCC) development in mice. In the present study, using human oral leukoplakia (MSK-Leuk1) and squamous cell carcinoma (SCC1483) cells, we tested the hypothesis that BRB extract (BRBE) will enhance the synthesis of glutathione (GSH) and in turn increase GSH conjugation of the fjord-region DBP diol epoxide (DBPDE) derived from DBP leading to inhibition of DBP-induced DNA damage. The syntheses of DBPDE-GSH conjugate, DBPDE-dA adduct, and the corresponding isotope-labeled internal standards were performed; LC-MS/MS methods were used for their quantification. BRBE significantly (p < 0.05) increased cellular GSH by 31% and 13% at 6 and 24 h, respectively, in OSCC cells; in MSK-LeuK1 cells, the levels of GSH significantly (p < 0.05) increased by 55% and 22%, at 1 and 6 h. Since BRBE significantly enhanced the synthesis of GSH in both cell types, subsequent experiments were performed in MSK-Leuk1 cells. Western blot analysis was performed to determine the types of proteins involved in the synthesis of GSH. BRBE significantly (p < 0.05) increased the protein expression (2.5-fold) of the glutamate-cysteine ligase catalytic subunit (GCLC) but had no effect on the glutamate-cysteine ligase modifier subunit (GCLM) and glutathione synthetase (GSS). LC-MS/MS analysis showed that pretreatment of cells with BRBE followed by DBPDE significantly (p < 0.05) increased the levels of DBPDE-GSH conjugate (2.5-fold) and decreased DNA damage by 74% measured by assessing levels of DBPDE-dA adduct formation. Collectively, the results of this in vitro study clearly support our hypothesis, and the LC-MS/MS methods developed in the present study will be highly useful in testing the same hypothesis initially in our mouse model and ultimately in smokers.

Prevention of carcinogen-induced oral cancers by polymeric black tea polyphenols via modulation of EGFR-Akt-mTOR pathway.

The overexpression of Epidermal Growth Factor Receptor (EGFR) and dysregulation of its downstream effector pathways are important molecular hallmarks of oral cancers. Present study investigates the chemopreventive potential of polymeric black tea polyphenols (PBPs)/thearubigins (TRs) in the hamster model of oral carcinogenesis as well as determine the effect of PBPs on EGFR and the molecular players in the EGFR pathway. In dose-dependent manner, pre and concurrent treatment with PBPs (1.5%, 5%, 10%) decreased the number and volume of macroscopic tumors as well as the number and area of microscopic lesions. Interestingly, at 10% dose of PBPs, no macroscopic or microscopic tumors were observed. We observed PBPs mediated dose-dependent decrease in oxidative DNA damage (8OHdG); inflammation (COX-2); proliferation (PCNA, Cyclin D1); expression of EGFR, and its downstream signaling kinases (pAkt, Akt, and mTOR); hypoxia (HIF1α) and angiogenesis (VEGF). There was also a PBPs mediated dose-dependent increase in apoptosis (Bax). Thus, our data clearly indicate that the observed chemopreventive potential of PBPs was due to modulation in the EGFR pathway associated with cell proliferation, hypoxia, and angiogenesis. Taken together, our results demonstrate preclinical chemopreventive efficacy of PBPs and give an insight into its mechanistic role in the chemoprevention of experimental oral cancer.

The Prevention and Treatment of Nausea and Vomiting During Tumor Therapy.

BACKGROUND: Nausea and vomiting are common and distressing side effects of tumor therapy. Despite prophylaxis, 40-50% of patients suffer from nausea, and 20-30% from vomiting. Antiemetic prophylaxis and treatment are therefore of great importance for improving patients' quality of life and preventing sequelae such as tumor cachexia. METHODS: The recommendations presented here are based on international and national guidelines, updated with publications retrieved by a selective search in the PubMed and Cochrane Library databases, with special attention to randomized controlled trials and meta-analyses that have appeared in the past 5 years since the German clinical practice guideline on supportive therapy was published. RESULTS: Risk-adjusted prevention and treatment is based on the identification of treatment-related and patient-specific risk factors, including female sex and younger age. Parenteral tumor therapy is divided into four risk classes (minimal, low, moderate, high), and oral tumor therapy into two (minimal/low, moderate/high). In radiotherapy, the radiation field is of decisive importance. The antiemetic drugs most commonly used are 5-HT3-RA, NK1-RA, and dexamethasone; olanzapine has proven beneficial as an add-on or rescue drug. The use of steroids in patients being treated with drug combinations including checkpoint inhibitors is discussed controversially because of the potentially reduced therapeutic response. Benzodiazepines, dimenhydrinate, and cannabinoids can be used as backup antiemetics. Acupuncture/acupressure, ginger, and progressive muscle relaxation are pos - sible alternative methods. CONCLUSION: Detailed, effective, risk profile-adapted algorithms for the prevention and treatment of nausea and vomiting are now available for patients undergoing classic chemotherapy regimens or combined radiotherapy and chemotherapy. Optimal symptom control for patients undergoing oral tumor therapy over multiple days in the outpatient setting remains a challenge.

Molecular Mechanisms of Malignant Transformation of Oral Submucous Fibrosis by Different Betel Quid Constituents-Does Fibroblast Senescence Play a Role?

Betel quid (BQ) is a package of mixed constituents that is chewed by more than 600 million people worldwide, particularly in Asia. The formulation of BQ depends on a variety of factors but typically includes areca nut, betel leaf, and slaked lime and may or may not contain tobacco. BQ chewing is strongly associated with the development of potentially malignant and malignant diseases of the mouth such as oral submucous fibrosis (OSMF) and oral squamous cell carcinoma (OSCC), respectively. We have shown recently that the constituents of BQ vary geographically and that the capacity to induce disease reflects the distinct chemical composition of the BQ. In this review, we examined the diverse chemical constituents of BQ and their putative role in oral carcinogenesis. Four major areca alkaloids-arecoline, arecaidine, guvacoline and guvacine-together with the polyphenols, were identified as being potentially involved in oral carcinogenesis. Further, we propose that fibroblast senescence, which is induced by certain BQ components, may be a key driver of tumour progression in OSMF and OSCC. Our study emphasizes that the characterization of the detrimental or protective effects of specific BQ ingredients may facilitate the development of targeted BQ formulations to prevent and/or treat potentially malignant oral disorders and oral cancer in BQ users.

Evaluation of the chemopreventive effects of Hypericum perforatum L on DMBA-applied rat oral mucosa.

OBJECTIVE: Hypericum perforatum L also known as St. John's wort is known to have many beneficial properties for the organism including its antioxidant and anticancer activities. It is also known to have shown antiproliferative and cytotoxic effects against various cancer cell lines. The purpose of this study was to investigate the effects of Hypericum perforatum L on 7,12-dimethylbenz(a)anthracene-induced rat oral squamous cell carcinoma model. DESIGN: The in vitro antioxidant properties of Hypericum perforatum L was determined and an extract was prepared. Thirty Wistar male rats were divided randomly into 4 groups (Control group, DMBA group, HP + DMBA group, HP group). The antioxidant defense mechanisms in tissue and blood samples were evaluated biochemically and immunohistochemically, the carcinomatous changes in connective tissue were investigated immunohistochemically and epithelial changes in the tissue samples were evaluated histopathologically. RESULTS: The extract revealed inhibitory effects on some antioxidant enzymes (catalase, glutathione peroxidase). Immunohistochemical evaluations revealed no invasive changes in the connective tissue. Hypericum perforatum L demonstrated chemopreventive effects although it did not prevent carcinomatous changes altogether. CONCLUSIONS: Hypericum perforatum L is a promising chemopreventive agent and further studies are needed in order to evaluate the full potential of this plant.

Chemopreventive effect of modified zengshengping on oral cancer in a hamster model and assessment of its effect on liver.

Ethnopharmacological relevance Oral squamous cell carcinoma (OSCC) is one of the most common malignant tumors, seriously compromising patients' quality of life. Previous studies showed that Zengshengping (ZSP), a popular traditional Chinese medicine, has certain inhibiting effects on both oral precancerous lesions and OSCC. However, few reports underlined ZSP side effects such as liver toxicity, which limit its long-term application. Aim of the study was to evaluate the chemopreventive effect of a modified ZSPs formula on oral cancer in a hamster model. Its effect on hamster liver was also assessed. Materials and Methods The original medicine (ZSP-1) and other two formulas slightly different and called ZSP-2 and ZSP-3 were prepared ahead of time. DMBA (0.5%) was topically applied for 6 weeks to induce a premalignant lesion on hamsters' cheek pouch, then ZSP-1/2/3 were intragastrically administered for 8 weeks. Hamster treated with DMBA + each of the ZSPs represented the ZSP-1/2/3 groups, while those without ZSP-1/2/3 treatment represented the DMBA group. To assess the effect of ZSPs in the liver, intragastric administration of ZSP-1/2/3 was carried out to other groups of hamsters for 12 weeks and the blood was collected every two weeks to detect the hepatic function. Some of the hamsters were sacrificed at the end of 12 weeks, while the remaining animals were sacrificed after other 4 weeks to estimate the effect of ZSP-1/2/3 withdrawal on the liver. Results showed that tumor development in the ZSP-1/2/3 groups was less than that in DMBA group. BrdU, CD31 and COX-2 expression in the hyperplastic tissues was significantly lower in the ZSP-1/2/3 groups than that in the DMBA group. In addition, VEGF and COX-2 expression in ZSP-1/2/3 groups was lower while caspase-9 and p53 expression was higher than those in the DMBA group. Finally, PTEN expression in ZSP-1/2/3 groups was higher than that in the DMBA group. As regard the effect in the liver, ALP in the ZSP-1/2/3 groups was higher than that in the control group treated with an intragastric administration of ddH2O. After 4 weeks of withdrawal, the hamsters of the ZSP-3 group did not recover from the increase in ALP. Histopathology showed the presence of inflammatory lesions in each group after 12 weeks, especially in the ZSP-1/3 groups, and the number of apoptotic cells in the ZSP-3 group was higher than that in the other groups, without any recovery after withdrawal of the drug. At 12 weeks, the MDA in the ZSP-1 group was higher than that in the control group and the ZSP-2 group, but the difference disappeared after drug withdrawal because the MDA in the ZSP-1/3 groups decreased. Conclusions ZSP-2 possessed a chemopreventive effect against oral cancer by inhibiting inflammation, proliferation of tumor cells, generation of microvessels and by promoting tumor cell apoptosis. In addition, hepatotoxicity of ZSP-2, which might be related to oxidative stress injury, was reduced to some extent.

Black Raspberry Inhibits Oral Tumors in Mice Treated with the Tobacco Smoke Constituent Dibenzo(def,p)chrysene Via Genetic and Epigenetic Alterations.

We previously reported that the environmental pollutant and tobacco smoke constituent dibenzo[def,p]chrysene (DBP) induced DNA damage, altered DNA methylation and induced oral squamous cell carcinoma (OSCC) in mice. In the present study, we showed that 5% dietary black raspberry (BRB) significantly reduced (P < 0.05) the levels of DBP-DNA adducts in the mouse oral cavity with comparable effect to those of its constitutes. Thus, only BRB was selected to examine if aberrant DNA methylation induced by DBP can be altered by BRB. Using comparative genome-wide DNA methylation analysis, we identified 479 hypermethylated and 481 hypomethylated sites (q < 0.01, methylation difference >25%) between the oral tissues of mice treated with DBP and fed control diet or diet containing BRB. Among the 30 differential methylated sites (DMS) induced by DBP, we found DMS mapped to Fgf3, Qrich2, Rmdn2, and Cbarp were hypermethylated by BRB whereas hypomethylated by DBP at either the exact position or proximal sites; DMS mapped to Vamp3, Ppp1rB1, Pkm, and Zfp316 were hypomethylated by BRB but hypermethylated by DBP at proximal sites. In addition to Fgf3, 2 DMS mapped to Fgf4 and Fgf13 were hypermethylated by BRB; these fibroblast growth factors are involved in regulation of the epithelial-mesenchymal transition (EMT) pathway as identified by IPA. Moreover, BRB significantly reduced (P < 0.05) the tumor incidence from 70% to 46.7%. Taken together, the inhibitory effects of BRB on DNA damage combined with its effects on epigenetic alterations may account for BRB inhibition of oral tumorigenesis induced by DBP. SIGNIFICANCE: We provided mechanistic insights that can account for the inhibition of oral tumors by BRB, which could serve as the framework for future chemopreventive trials for addicted smokers as well as non- or former smokers who are exposed to environmental carcinogens.

Impact of dietary vitamin D on initiation and progression of oral cancer.

Calcitriol, the active metabolite of vitamin D, has been widely studied for its preventive and therapeutic activity against several cancers including oral squamous cell carcinoma (OSCC). However, the impact of dietary vitamin D supplementation on initiation and progression of OSCC is unclear. To address this gap in knowledge, we conducted preclinical trials using the 4-nitroquinoline-1-oxide 4NQO carcinogen model of oral carcinogenesis. Female C57BL/6 mice were maintained on one of three vitamin D diets [25 IU, 100 IU, 10,000 IU] and exposed to 4NQO in drinking water for 16 weeks followed by regular water for 10 weeks. Body weight measurements obtained through the study duration did not reveal any differences between the three diets. Animals on 100 IU diet showed lower incidence of high-grade dysplasia/OSCC and higher CD3 + T cells compared to animals on 25 IU and 10,000 IU diets. Serum 25OHD3 levels were highest in animals on 10,000 IU diet at week 0 prior to carcinogen exposure but showed ∼50 % reduction at week 26. Histologic evaluation revealed highest incidence of OSCC in animals maintained on 10,000 IU diet. Animals on 100 IU and 10,000 IU diets showed higher vitamin D receptor VDR and CYP24A1 immunostaining in high-grade dysplastic lesions and OSCC compared to normal tongue. Validation studies performed in a 4NQO-derived OSCC model showed that short-term treatment of animals on a 25 IU diet with calcitriol significantly inhibited tumor growth compared to controls but did not affect tumor growth in animals on reference diet 1000 IU. Collectively, our results highlight the complex dynamics between vitamin D status and oral carcinogenesis. Our observations also suggest that therapeutic benefits of short-term calcitriol treatment may be more pronounced in vitamin D deficient hosts.

Methanolic extract of Potentilla fulgens root and its ethyl-acetate fraction delays the process of carcinogenesis in mice.

People of north-eastern states of India consume raw areca-nut (RAN) and lime which could lead to oral, esophageal and gastric cancers. However, the incidence of these cancers are significantly lesser in those who consume pieces of Potentilla fulgens root along with RAN. Since evaluation of anticancer role, if any, of P. fulgens on RAN-mediated genetic alterations in human is difficult because of other compounding factors, this study was undertaken in mice to focus on gastric carcinogenesis since ad libitum administration of RAN extract with lime in drinking water induced stomach cancer due to greater exposure of its lining. A total of 160 mice were used at different time points and either methanol extract of P. fulgens roots (PRE) or mixture of four compounds of ethyl-acetate fraction (EA-mixture) was mixed with mice feed. Histological studies revealed that RAN + lime induced cancer in all the mice and interestingly only 20% developed cancer when PRE/EA-mixture was provided along with RAN + lime. Higher frequency of precocious anaphase and over expression of p53 and Securin genes were significantly reduced by PRE/EA-mixture. Thus PRE/EA-mixture mitigates the RAN-induced tumor-initiating process in stomach by maintaining expression of tumor suppressor and check-point genes under control.

Red propolis and L-lysine on angiogenesis and tumor growth in a new model of hamster cheek pouch inoculated with Walker 256 tumor cells.

OBJECTIVE: To evaluate the effect of red propolis and L-lysine on angiogenesis and tumor growth in a new model of hamster cheek pouch inoculated with Walker 256 tumor cells. METHODS: The study consisted of two experiments with four groups each (total: 57 hamsters). In the experiment 1, the animals were inoculated with Walker tumor cells, followed by administration of test substances (red propolis 200mg/5mL/kg or L-lysine 150mg/kg) or control substances (gum arabic 5mL/kg or water 5mL/kg) for 10 days. The animals in the experiment 2 received red propolis, L-lysine, gum arabic or water at the same doses, for 33 days prior to inoculation of Walker tumor cells, followed by 10 days of treatment with the same substances. Based on single-plane images, angiogenesis was quantified (mean vascular area), in percentage, and tumor area (mm2) and perimeter (mm). RESULTS: In the experiment 1, compared to animals receiving water, the mean vascular area expressed in percentage was significantly smaller in animal treated with propolis (p<0.05) and L-lysine (p<0.001). CONCLUSION: Both red propolis and L-lysine inhibited tumor angiogenesis in the new hamster cheek pouch model when administered after tumor inoculation.

Secretome analysis of oral keratinocytes chronically exposed to shisha.

BACKGROUND: Shisha smoking has been associated with multiple diseases including oral cancer. However, a mechanistic study to investigate alteration of secreted proteins in oral cells due to shisha smoking is lacking. OBJECTIVES: Elucidation of differentially secreted proteins by immortalized human normal oral keratinocytes (OKF6/TERT1) upon chronic exposure to shisha. METHODS: OKF6/TERT1 was chronically treated with 0.5% shisha extract for 8 months. Conditioned media from shisha treated (OKF6/TERT1-Shisha) and untreated (OKF6/TERT1-Parental) cells were subjected to TMT-based quantitative proteomic analysis. Bioinformatics analysis of differentially secreted proteins was carried out using SignalP, SecretomeP and TMHMM. Immunoblot validation of selected proteins was carried out to confirm the proteomics results. RESULTS: Proteomic analysis of OKF6/TERT1-Parental and OKF6/TERT1-Shisha secretome resulted in the identification of 1,598 proteins, of which 218 proteins were found to be differentially secreted (⩾ 1.5-fold; p-value ⩽ 0.05) in shisha treated cells. Bioinformatics analysis using prediction tools showed secretory potential of differentially secreted proteins identified in OKF6/TERT1-Shisha. Western blotting validated the expression of AKR1C2, HSPH1 and MMP9 in OKF6/TERT1-Shisha secretome in agreement with proteomic data. CONCLUSION: This study serves as a useful resource to understand the effect of chronic shisha smoking on the milieu of secreted proteins of oral cells. In vivo studies are warranted to supplement our in vitro data to elucidate the role of these proteins as early diagnostic biomarkers for oral carcinogenesis among shisha smokers.

Occupational exposure to petroleum-based and oxygenated solvents and oral and oropharyngeal cancer risk in men: A population-based case-control study in France.

OBJECTIVE: To examine the association between occupational exposure to petroleum-based and oxygenated solvents and the risk of oral and oropharyngeal cancer. METHODS: The ICARE study is a large population-based case-control study conducted in France between 2001 and 2007. This present analysis was restricted to men and included 350 and 543 cases of squamous cell-carcinoma of the oral cavity and oropharynx, respectively, and 2780 controls. Lifetime tobacco, alcohol consumption and complete occupational history were assessed through detailed questionnaires. Job-exposure matrices allowed us to assess occupational exposure to five petroleum-based solvents (white spirits; diesel/fuel oils/kerosene; gasoline; benzene; special petroleum products) and five oxygenated solvents (diethyl ether; tetrahydrofuran; ketones and esters; alcohols; ethylene glycol). Odds-ratios (ORs), adjusted for age, smoking, alcohol consumption and socioeconomic status, and 95% confidence intervals (CI) were estimated using unconditional logistic models. RESULTS: Associations between oral cancer risk and exposure to white spirits and diesel/fuel oils/kerosene were suggested, but there was no exposure-response trend. Concerning exposure to oxygenated solvents, participants with the highest levels of cumulative exposure to diethyl ether had a significant excess risk of oropharyngeal cancer (OR = 7.78, 95%CI 1.42 to 42.59; p for trend = 0.04). Ever exposure to tetrahydrofuran was associated with a borderline significant increased risk of oral cancer (OR = 1.87, 95%CI 0.97 to 3.61), but no exposure-response trend was observed. Additional adjustments for exposure to other solvents did not substantially change the results. CONCLUSION: Our results do not provide evidence for a major role of petroleum-based and oxygenated solvents in the occurrence of oral and oropharyngeal cancers in men.

Prevention of oral carcinogenesis in rats by Dracaena cinnabari resin extracts.

OBJECTIVES: In vivo study was performed to determine the chemopreventive efficacy of the DC resin methanol extract on a 4-nitroquinoline-1-oxide (4NQO) oral cancer animal model. MATERIALS AND METHODS: This study involves administration of 4NQO solution for 8 weeks alone (cancer induction) or with Dracaena cinnabari (DC) extract at 100, 500, and 1000 mg/kg. DC extract administration started 1 week before exposure until 1 week after the carcinogen exposure was stopped. All rats were sacrificed after 22 weeks, and histological analysis was performed to assess any incidence of pathological changes. Immunohistochemical expressions of selected tumor marker antibodies were analyzed using an image analyzer computer system, and the expression of selected genes involved in apoptosis and proliferative mechanism related to oral cancer were evaluated using RT2-PCR. RESULTS: The incidence of OSCC decreased with the administration of DC extract at 100, 500, and 1000 mg/kg compared to the induced cancer group. The developed tumor was also observed to be smaller when compared to the induced cancer group. The DC 1000 mg/kg group inhibits the expression of Cyclin D1, Ki-67, Bcl-2, and p53 proteins. It was observed that DC 1000 mg/kg induced apoptosis by upregulation of Bax and Casp3 genes and downregulation of Tp53, Bcl-2, Cox-2, Cyclin D1, and EGFR genes when compared to the induced cancer group. CONCLUSIONS: The data indicated that systemic administration of the DC resin methanol extract has anticarcinogenic potency on oral carcinogenesis. CLINICAL RELEVANCE: Chemoprevention with DC resin methanol extract may significantly reduce morbidity and possibly mortality from OSCC.

Evaluation of the Chemopreventive Activity of Grape Skin Extract Using Medium-term Oral Carcinogenesis Assay Induced by 4-Nitroquinoline 1-Oxide.

BACKGROUND/AIM: The aim of this study was to evaluate the chemoprotective potential of grape skin extract following rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide (4NQO). MATERIALS AND METHODS: Male Wistar rats were distributed into four groups (n=5, per group): Control Group: free access to commercial diet and drinking water for 12 weeks; 4NQO Group: received 4NQO diluted in drinking water daily, for 12 weeks; Grape Skin Extract Group: free access to water and received grape skin extract incorporated with diet for 12 weeks; 4NQO + Grape Skin Extract Group: received 4NQO in drinking water daily and grape extract incorporated with diet for 12 weeks. RESULTS: Animals treated with grape skin extract revealed a significant reduction in epithelial dysplasia. Also, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and ki-67 immunoexpression was reduced in animals treated with grape skin extract. Western blot analysis showed a significant decrease of p-NFκB p50 and MyD88 protein expression in the groups treated with grape skin extract. Copper-zinc superoxide dismutase, manganese superoxide dismutase, and catalase gene expression did not present any statistically significant differences (p>0.05). CONCLUSION: Grape skin extract displayed chemopreventive activity in oral carcinogenesis assays as depicted by its antioxidant, anti-proliferative and anti-inflammatory properties.

Red propolis and L-lysine on angiogenesis and tumor growth in a new model of hamster cheek pouch inoculated with Walker 256 tumor cells / Própolis vermelha e L-lisina na angiogênese e no crescimento tumoral em novo modelo de bolsa jugal de hamster inoculada com células de tumor de Walker 256

ABSTRACT Objective: To evaluate the effect of red propolis and L-lysine on angiogenesis and tumor growth in a new model of hamster cheek pouch inoculated with Walker 256 tumor cells. Methods: The study consisted of two experiments with four groups each (total: 57 hamsters). In the experiment 1, the animals were inoculated with Walker tumor cells, followed by administration of test substances (red propolis 200mg/5mL/kg or L-lysine 150mg/kg) or control substances (gum arabic 5mL/kg or water 5mL/kg) for 10 days. The animals in the experiment 2 received red propolis, L-lysine, gum arabic or water at the same doses, for 33 days prior to inoculation of Walker tumor cells, followed by 10 days of treatment with the same substances. Based on single-plane images, angiogenesis was quantified (mean vascular area), in percentage, and tumor area (mm2) and perimeter (mm). Results: In the experiment 1, compared to animals receiving water, the mean vascular area expressed in percentage was significantly smaller in animal treated with propolis (p<0.05) and L-lysine (p<0.001). Conclusion: Both red propolis and L-lysine inhibited tumor angiogenesis in the new hamster cheek pouch model when administered after tumor inoculation.

RESUMO Objetivo: Avaliar o efeito da própolis vermelha e da L-lisina na angiogênese e no crescimento tumoral em novo modelo de bolsa jugal de hamster inoculada com células de tumor de Walker 256. Métodos: O estudo consistiu em dois experimentos com quatro grupos cada (total: 57 hamsters). No experimento 1, os animais foram inoculados com células de tumor de Walker, tendo em seguida administradas as substâncias teste (própolis vermelha 200mg/5mL/kg ou L-lisina 150mg/kg) ou controle (goma arábica 5mL/kg ou água 5mL/kg) por 10 dias. Os animais do experimento 2 receberam própolis vermelha, L-lisina, goma arábica ou água nas mesmas doses, por 33 dias antes do inóculo das células de tumor de Walker, seguido por 10 dias de tratamento com as mesmas substâncias. Baseado em imagens em plano único, foram quantificados a angiogênese (área vascular média), em termos percentuais, e a área (mm2) e o perímetro (mm) do tumor. Resultados: Comparada aos animais que receberam água, a área vascular média, expressa em percentagem, foi significativamente menor nos animais tratados com própolis (p<0,05) e com L-lisina (p<0,001). Conclusão: Tanto a própolis vermelha quanto a L-lisina inibiram a angiogênese no novo modelo de bolsa jugal de hamsters, quando administradas após a inoculação do tumor.

Nimbolide, a neem limonoid inhibits cytoprotective autophagy to activate apoptosis via modulation of the PI3K/Akt/GSK-3ß signalling pathway in oral cancer.

Of late, nimbolide, a limonoid from the neem tree (Azadirachta indica) has gained increasing research attention owing to its potent antiproliferative and apoptosis-inducing effects. The present study was designed to investigate the effect of nimbolide on autophagy and the time point at which the phosphorylation status of GSK-3ß and PI3K dictate the choice between autophagy and apoptosis in SCC131 and SCC4 oral cancer cells. Additionally, we analysed changes in the expression of proteins involved in autophagy and apoptosis after therapeutic intervention with nimbolide in a hamster model of oral oncogenesis. Furthermore, we also demonstrate changes in the expression of key genes involved in apoptosis and autophagy during the stepwise evolution of hamster and human OSCCs. Nimbolide-induced stereotypical changes in oral cancer cells characteristic of both apoptosis and autophagy. Time-course experiments revealed that nimbolide induces autophagy as an early event and then switches over to apoptosis. Nimbolide negatively regulates PI3K/Akt signalling with consequent increase in p-GSK-3ßTyr216, the active form of GSK-3ß that inhibits autophagy. Downregulation of HOTAIR, a competing endogenous RNA that sponges miR-126 may be a major contributor to the inactivation of PI3K/Akt/GSK3 signalling by nimbolide. Analysis of key markers of apoptosis and autophagy as well as p-AktSer473 during sequential progression of hamster and human OSCC revealed a gradual evolution to a pro-autophagic and antiapoptotic phenotype that could confer a survival advantage to tumors. In summary, the results of the present study provide insights into the molecular mechanisms by which nimbolide augments apoptosis by overcoming the shielding effects of cytoprotective autophagy through modulation of the phosphorylation status of Akt and GSK-3ß as well as the ncRNAs miR-126 and HOTAIR. Development of phytochemicals such as nimbolide that target the complex interaction between proteins and ncRNAs that regulate the autophagy/apoptosis flux is of paramount importance in cancer prevention and therapeutics.