Suppression of Rat Oral Carcinogenesis by Agonists of Peroxisome Proliferator Activated Receptor γ

Three-Dimensional Printing of an Apigenin-Loaded Mucoadhesive Film for Tailored Therapy to Oral Leukoplakia and the Chemopreventive Effect on a Rat Model of Oral Carcinogenesis

Oral leukoplakia, which presents as white lesions in the oral cavity, including on the tongue, is precancerous in nature. Conservative treatment is preferable, since surgical removal can markedly reduce the patient’s quality of life. In the present study, we focused on the flavonoid apigenin as a potential compound for preventing carcinogenesis, and an apigenin-loaded mucoadhesive oral film was prepared using a three-dimensional (3D) bioprinter (semi-solid extrusion-type 3D printer). Apigenin-loaded printer inks are composed of pharmaceutical excipients (HPMC, CARBOPOL, and Poloxamer), water, and ethanol to dissolve apigenin, and the appropriate viscosity of printer ink after adjusting the ratios allowed for the successful 3D printing of the film. After drying the 3D-printed object, the resulting film was characterized. The chemopreventive effect of the apigenin-loaded film was evaluated using an experimental rat model that had been exposed to 4-nitroquinoline 1-oxide (4NQO) to induce oral carcinogenesis. Treatment with the apigenin-loaded film showed a remarkable chemopreventive effect based on an analysis of the specimen by immunohistostaining. These results suggest that the apigenin-loaded mucoadhesive film may help prevent carcinogenesis. This successful preparation of apigenin-loaded films by a 3D printer provides useful information for automatically fabricating other tailored films (with individual doses and shapes) for patients with oral leukoplakia in a future clinical setting.

The p38/MKP-1 signaling axis in oral cancer: Impact of tumor-associated macrophages

Oral squamous cell carcinomas (OSCC) constitute over 95% of all head and neck malignancies. As a key component of the tumor microenvironment (TME), chronic inflammation contributes towards the development, progression, and regional metastasis of OSCC. Tumor associated macrophages (TAMs) associated with OSSC promote tumorigenesis through the production of cytokines and pro-inflammatory factors that are critical role in the various steps of malignant transformation, including tumor growth, survival, invasion, angiogenesis, and metastasis. The mitogen-activated protein kinases (MAPKs) can regulate inflammation along with a wide range of cellular processes including cell metabolism, proliferation, motility, apoptosis, survival, differentiation and play a crucial role in cell growth and survival in physiological and pathological processes including innate and adaptive immune responses. Dual specificity MAPK phosphatases (MKPs) deactivates MAPKs. MKPs are considered as an important feedback control mechanism that limits MAPK signaling and subsequent target gene expression. This review outlines the role of MKP-1, the founding member of the MKP family, in OSCC and the TME. Herein, we summarize recent progress in understanding the regulation of p38 MAPK/MKP-1 signaling pathways via TAM-related immune responses in OSCC development, progression and treatment outcomes.

Chemopreventive activity of Tualang honey against oral squamous cell carcinoma-in vivo

OBJECTIVE

The aim of this study was to evaluate the chemopreventive activity of Malaysian jungle Tualang honey (TH) after oral carcinogenesis induced with 4-nitroquinoline 1-oxide (4 NQO).

STUDY DESIGN

A total of 28 male Sprague-Dawley (SD) rats were distributed into 4 groups as follows: group 1 (nontreated group); group 2 (control), which received 4 NQO during 8 weeks in drinking water only; and groups 3 and 4, which received 4 NQO for 8 weeks in drinking water and treated with TH 1000 mg/kg and 2000 mg/kg by oral gavage for 10 weeks. All rats from all experiments were sacrificed after 22 weeks, and the incidence of oral neoplasms and histopathologic changes were microscopically evaluated. Moreover, immunohistochemical expression was analyzed in tongue specimens by using image analysis software. The expression of particular genes associated with oral cancer were assessed by using RT² Profiler PCR Array (Qiagen, Germantown, MD).

RESULTS

TH significantly reduced the incidence of oral squamous cell carcinoma (OSCC) and suppressed cancer cell proliferation via diminishing the expression of CCND1, EGFR, and COX-2. Furthermore, TH preserved cellular adhesion (epithelial polarity) through overexpression of β-catenin and e-cadherin and inhibited the OSCC aggressiveness by downregulating TWIST1 and RAC1.

CONCLUSIONS

Our data suggest that TH exerts chemopreventive activity in an animal model in which oral cancer was induced by using 4 NQO.

The in vitro and in vivo antitumor effects of Dracaena cinnabari resin extract on oral cancer

OBJECTIVE

To study the potential for apoptosis induction of Dracaena cinnabari Balf. f methanolic extract (DCBME) on tongue squamous cell carcinoma cell line, H103. We evaluated the chemopreventive activity of DCBME against 4-nitroquinolone-1-oxide (4NQO)-induced tongue carcinogenesis in rat.

DESIGN

Phase contrast microscope, acridine orange/propidium iodide (AO/PI) analysis of cells under fluorescence microscope, annexin-V flow-cytometry, DNA fragmentation, mitochondrial membrane potential, and caspase 3/7, 8 and 9 assays were performed. In vivo study, the rats were given 4NQO in their drinking water. The tongue was subjected to histopathological study to evaluate the incidence of squamous cell carcinoma (SCC).

RESULTS

DCBME showed cytotoxic effect on H103 cells in a dose- and time-dependent manner. Furthermore, DCBME showed low cytotoxic effect on a normal cell line. In H103 cells, it caused cell morphology changes, S and G2/M-phase cell cycle arrest, significant reduction of cell migration and induced apoptosis through the intrinsic (mitochondrial) pathway. The incidence of SCC was 85.7% in the induced cancer and vehicle groups while in rats treated with DCBME at 100, 500 and 1000 mg/kg was 57.1%, 28.6% and 14.3%, respectively.

CONCLUSIONS

(DCBME)-apoptosis induction reported in this work can be exploited as a potential antitumor agent with applications in medicinal treatments of tongue SCC.

Peroxisome proliferator-activated receptor gamma and BRCA1

Peroxisome proliferator-activated receptor gamma agonists have been proposed as breast cancer preventives. Individuals who carry a mutated copy of BRCA1, DNA repair-associated gene, are at increased risk for development of breast cancer. Published data in the field suggest there could be interactions between peroxisome proliferator-activated receptor gamma and BRCA1 that could influence the activity of peroxisome proliferator-activated receptor gamma agonists for prevention. This review explores these possible interactions between peroxisome proliferator-activated receptor gamma, peroxisome proliferator-activated receptor gamma agonists and BRCA1 and discusses feasible experimental directions to provide more definitive information on the potential connections.

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.

Porphyromonas gingivalis Promotes 4-Nitroquinoline-1-Oxide-Induced Oral Carcinogenesis With an Alteration of Fatty Acid Metabolism

Microbiota has been widely considered to play a critical role in human carcinogenesis. Human papilloma virus, hepatitis B and C virus, and Helicobacter pylori are implicated in the pathogenesis of cancer of uterine cervix, liver, and stomach, respectively. However, whether Porphyromonas gingivalis (P. gingivalis), a common Gram negative oral bacteria, is associated with oral carcinogenesis still remains unclear and its underlying mechanism needs to be addressed. Here, we established a combined experimental system of 4NQO-induced oral carcinoma model and chronic periodontitis model and investigated the effects of P. gingivalis infection on oral carcinogenesis and fatty acid metabolism during oral carcinogenesis. The data showed that in this animal model, P. gingivalis infection induced mice periodontitis, increased the tongue lesion size and multiplicity of each mouse and promoted oral cancer development. P. gingivalis treatment significantly increased the level of free fatty acids and altered the fatty acid profile in tongue tissues and the serum of mice. And P. gingivalis induced the formation of fatty liver of the mice. Besides, immunohistochemical analysis and qRT-PCR showed that the expression of fatty-acid synthase and acetyl-CoA carboxylase 1 were increased in the tongue and liver tissues of 4NQO-treated mice infected with P. gingivalis. These results showed that P. gingivalis promoted oral carcinogenesis and aggravated disturbance of fatty acid metabolism, indicating a close association among P. gingivalis, lipid metabolic and oral carcinogenesis.

Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas

This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing molecular features of squamous cell carcinomas (SCCs) from five sites associated with smoking and/or human papillomavirus (HPV). SCCs harbor 3q, 5p, and other recurrent chromosomal copy-number alterations (CNAs), DNA mutations, and/or aberrant methylation of genes and microRNAs, which are correlated with the expression of multi-gene programs linked to squamous cell stemness, epithelial-to-mesenchymal differentiation, growth, genomic integrity, oxidative damage, death, and inflammation. Low-CNA SCCs tended to be HPV(+) and display hypermethylation with repression of TET1 demethylase and FANCF, previously linked to predisposition to SCC, or harbor mutations affecting CASP8, RAS-MAPK pathways, chromatin modifiers, and immunoregulatory molecules. We uncovered hypomethylation of the alternative promoter that drives expression of the ΔNp63 oncogene and embedded miR944. Co-expression of immune checkpoint, T-regulatory, and Myeloid suppressor cells signatures may explain reduced efficacy of immune therapy. These findings support possibilities for molecular classification and therapeutic approaches.

Bronchial airway gene expression signatures in mouse lung squamous cell carcinoma and their modulation by cancer chemopreventive agents

Due to exposure to environmental toxicants, a “field cancerization” effect occurs in the lung resulting in the development of a field of initiated but morphologically normal appearing cells in the damaged epithelium of bronchial airways with dysregulated gene expression patterns. Using a mouse model of lung squamous cell carcinoma (SCC), we performed transcriptome sequencing (RNA-Seq) to profile bronchial airway gene expression and found activation of the PI3K and Myc signaling networks in cytologically normal bronchial airway epithelial cells of mice with preneopastic lung SCC lesions, which was reversed by treatment with the PI3K Inhibitor XL-147 and pioglitazone, respectively. Activated MYC signaling was also present in premalignant and tumor tissues from human lung SCC patients. In addition, we identified a key microRNA, mmu-miR-449c-5p, whose suppression significantly up-regulated Myc expression in the normal bronchial airway epithelial cells of mice with early stage SCC lesions. We developed a novel bronchial genomic classifier in mice and validated it in humans. In the classifier, Ppbp (pro-platelet basic protein) was overexpressed 115 fold in the bronchial airways of mice with preneoplastic lung SCC lesions. This is the first report that demonstrates Ppbp as a novel biomarker in the bronchial airway for lung cancer diagnosis.

Lack of chemopreventive efficacy of metformin in rodent models of urinary bladder, head and neck, and colon/intestine cancer

Metformin is a biguanide employed in treating type II diabetes. Its potential efficacy for treating cancer has been demonstrated epidemiologically (lower cancer incidence in metformin users compared with users of sulfonylureas or insulin) and mechanistically, primarily in cell culture. Metformin decreases the levels of insulin-like growth factor 1 and secondarily inhibits the mammalian target of rapamycin pathway to exhibit anticancer effects. The current study examined its cancer preventive efficacy in multiple standard in situ arising cancer models. Metformin was administered orally by gavage or in the diet, at human equivalent doses, in numerous cancer models. In the hydroxybutyl(butyl)nitrosamine-induced model of invasive urinary bladder cancer, metformin (50 or 150 mg/kg body weight/day, intragastric) was ineffective despite high urinary concentrations of metformin. Metformin (250 or 500 ppm in diet) failed to decrease the incidence or invasiveness of squamous cell cancer of the tongue in a 4-nitroquinoline-1-(4NQO)-induced model. Finally, in the Min mouse model of gastrointestinal cancer, metformin (400 or 1,200 ppm in diet) was ineffective. Notably, a slight increase in intestinal tumor multiplicity was observed at the higher dose. Therefore, metformin lacked efficacy in multiple standard cancer models in non-diabetic rodents. This lack of efficacy may discourage any large phase clinical cancer trials in non-diabetic individuals in the absence of clear phase-II studies.

Pioglitazone inhibits growth of human retinoblastoma cells via regulation of NF-κB inflammation signals

OBJECTIVES

We aimed to study the antitumor effects of the PPARγ agonist pioglitazone on human retinoblastoma.

METHODS

The effects of pioglitazone on cell proliferation and apoptosis of the human retinoblastoma Y79 cells were investigated by MTT assay and Hoechst 33258 staining assay. The apoptosis related protein levels were detected by western blot. Inflammationary factors analysis was evaluated by western blot and ELISA. The effect of pioglitazone on nuclear factor-kappa B (NF-κB)-dependent reporter gene transcription induced by LPS was analyzed by NF-κB-luciferase assay. Then human retinoblastoma Y79 cells were subcutaneously transplanted in BALB/c nude mice and the animals were treated with pioglitazone to verify its antitumor effect in vivo.

RESULTS

Our data revealed that pioglitazone suppressed the viability of Y79 cells dose- and time-dependently and induced apoptosis in Y79 cells in vitro. Molecular biology analysis found that pioglitazone could affect the apoptosis and inflammation related signal via modulating the activity of NF-κB signal. Also we found that pioglitazone could markedly reduce the growth of Y79 cells transplanted into the mice without causing significant side effects.

CONCLUSIONS

Our results suggested that pioglitazone demonstrated antitumor activity against the human retinoblastoma Y79 cells by inhibiting cell growth, inducing apoptosis and modulating NF-κB pathway, and thus delayed tumor growth in vivo.