Chemoprevention of premalignant and malignant lesions of oral cavity: Recent trends

Chemopreventive and Biological Strategies in the Management of Oral Potentially Malignant and Malignant Disorders

Oral potentially malignant disorders (OPMD) and oral squamous cell carcinoma (OSCC) represent a significant global health burden due to their potential for malignant transformation and the challenges associated with their diagnosis and treatment. Chemoprevention, an innovative approach aimed at halting or reversing the neoplastic process before full malignancy, has emerged as a promising avenue for mitigating the impact of OPMD and OSCC. The pivotal role of chemopreventive strategies is underscored by the need for effective interventions that go beyond traditional therapies. In this regard, chemopreventive agents offer a unique opportunity to intercept disease progression by targeting the molecular pathways implicated in carcinogenesis. Natural compounds, such as curcumin, green tea polyphenols, and resveratrol, exhibit anti-inflammatory, antioxidant, and anti-cancer properties that could make them potential candidates for curtailing the transformation of OPMD to OSCC. Moreover, targeted therapies directed at specific molecular alterations hold promise in disrupting the signaling cascades driving OSCC growth. Immunomodulatory agents, like immune checkpoint inhibitors, are gaining attention for their potential to harness the body's immune response against early malignancies, thus impeding OSCC advancement. Additionally, nutritional interventions and topical formulations of chemopreventive agents offer localized strategies for preventing carcinogenesis in the oral cavity. The challenge lies in optimizing these strategies for efficacy, safety, and patient compliance. This review presents an up to date on the dynamic interplay between molecular insights, clinical interventions, and the broader goal of reducing the burden of oral malignancies. As research progresses, the synergy between early diagnosis, non-invasive biomarker identification, and chemopreventive therapy is poised to reshape the landscape of OPMD and OSCC management, offering a glimpse of a future where these diseases are no longer insurmountable challenges but rather preventable and manageable conditions.

Molecular docking analysis of capsaicin with apoptotic proteins

Oral cancer is linked with apoptotic proteins such as Bcl-xl, Bcl-2 and Mcl-1. Therefore it is of interest to document the molecular docking analysis of capsaicin (principle present in the Capsicum annum) with apoptotic proteins in this context. We report the molecular binding features of capsaicin with apoptotic proteins such as Bcl-xl, Bcl-2 and Mcl-1 for further consideration.

Wnt/β-Catenin Signaling in Oral Carcinogenesis

Oral carcinogenesis is a complex and multifactorial process that involves cumulative genetic and molecular alterations, leading to uncontrolled cell proliferation, impaired DNA repair and defective cell death. At the early stages, the onset of potentially malignant lesions in the oral mucosa, or oral dysplasia, is associated with higher rates of malignant progression towards carcinoma in situ and invasive carcinoma. Efforts have been made to get insights about signaling pathways that are deregulated in oral dysplasia, as these could be translated into novel markers and might represent promising therapeutic targets. In this context, recent evidence underscored the relevance of the Wnt/β-catenin signaling pathway in oral dysplasia, as this pathway is progressively "switched on" through the different grades of dysplasia (mild, moderate and severe dysplasia), with the consequent nuclear translocation of β-catenin and expression of target genes associated with the maintenance of representative traits of oral dysplasia, namely cell proliferation and viability. Intriguingly, recent studies provide an unanticipated connection between active β-catenin signaling and deregulated endosome trafficking in oral dysplasia, highlighting the relevance of endocytic components in oral carcinogenesis. This review summarizes evidence about the role of the Wnt/β-catenin signaling pathway and the underlying mechanisms that account for its aberrant activation in oral carcinogenesis.

Progress in Drug and Formulation Development for the Chemoprevention of Oral Squamous Cell Carcinoma: A Review

BACKGROUND

Cancer is a life-threatening global problem with high incidence rates. Prioritizing the prevention of cancer, chemopreventive agents have drawn much attention from the researchers.

OBJECTIVE

This review focuses on the discussion of the progress in the development of chemopreventive agents and formulations related to the prevention of oral cancer.

METHODS

In this perspective, an extensive literature survey was carried out to understand the mechanism, control and chemoprevention of oral cancer. Different patented agents and formulations have also exhibited cancer preventive efficacy in experimental studies. This review summarizes the etiology of oral cancer and developments in prevention strategies.

RESULTS

The growth of oral cancer is a multistep activity necessitating the accumulation of genetic as well as epigenetic alterations in key regulatory genes. Many risk factors are associated with oral cancer. Genomic technique for sequencing all tumor specimens has been made available to help detect mutations. The recent development of molecular pathway and genetic tools has made the process of diagnosis easier, better forecast and efficient therapeutic management. Different chemical agents have been studied for their efficacy to prevent oral cancer and some of them have shown promising results.

CONCLUSION

Use of chemopreventive agents, either synthetic or natural origin, to prevent carcinogenesis is a worthy concept in the management of cancers. Preventive measures are helpful in controlling the occurrence or severity of the disease. The demonstrated results of preventive agents have opened an arena for the development of promising chemopreventive agents in the management of oral squamous cell carcinoma.

Polymeric drug delivery systems for intraoral site-specific chemoprevention of oral cancer

Oral cancer is among the most prevalent cancers in the world. Moreover, it is one of the major health problems and causes of death in many regions of the world. The traditional treatment modalities include surgical removal, radiation therapy, systemic chemotherapy, or a combination of these methods. In recent decades, there has been significant interest in intraoral site-specific chemoprevention via local drug delivery using polymeric systems. Because of its easy accessibility and clear visibility, the oral mucosa is amenable for local drug delivery. A variety of polymeric systems-such as gels, tablets, films, patches, injectable systems (e.g., millicylindrical implants, microparticles, and in situ-forming depots), and nanosized carriers (e.g., polymeric nanoparticles, nanofibers, polymer-drug conjugates, polymeric micelles, nanoliposomes, nanoemulsions, and polymersomes)-have been developed and evaluated for the local delivery of natural and synthetic chemopreventive agents. The findings of in vitro, ex vivo, and in vivo studies and the positive outcome of clinical trials demonstrate that intraoral site-specific drug delivery is an attractive, highly effective and patient-friendly strategy for the management of oral cancer. Intraoral site-specific drug delivery provides unique therapeutic advantages when compared to systemic chemotherapy. Moreover, intraoral drug delivery systems are self-administrable and can be removed when needed, increasing patient compliance. This article covers important aspects and advances related to the design, development, and efficacy of polymeric systems for intraoral site-specific drug delivery. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1383-1413, 2018.

Estimation of serum, salivary immunoglobulin G, immunoglobulin A levels and total protein, hemoglobin in smokeless tobacco chewers and oral submucous fibrosis patients

BACKGROUND

Oral submucous fibrosis (OSMF) is a debilitating, potentially cancerous oral condition. Although areca nut is the most important causative agent, it is also considered that the disease is immunologically mediated.

AIM OF THE STUDY

To establish that autoimmunity and nutritional deficiency play a role in the etiopathogenesis of OSMF.

OBJECTIVES OF THE STUDY

To show that serum immunoglobulin markers (immunoglobulin-G [IgG], immunoglobulin-A [IgA]) and nutritional parameters such as total serum protein (TSP), Hemoglobin (Hb) play a role in causing OSMF and also to correlate serum, salivary IgG, IgA levels in OSMF patients.

SETTINGS AND DESIGN

A case-control study was done with 50 patients (25 patients who were provisionally diagnosed as OSMF - Group I, and 25 patients who were chronic smokeless tobacco chewers and who did not have any intraoral lesion - Group II).

MATERIALS AND METHODS

Five milliliters of blood and saliva were collected from both the groups. Quantitative analysis of serum, and salivary IgG, IgA was done by turbidometric immunoassay. TSP and Hemoglobin (Hb) were estimated by spectrophotometry.

STATISTICAL ANALYSIS

Results were analyzed by independent samples t-test and one-way analysis of variance (ANOVA).

RESULTS

All patients of OSMF showed significant (P < 0.01) increase in serum IgG, IgA, and salivary IgG levels as compared to smokeless tobacco chewers. The salivary IgA levels showed a significant decrease in OSMF patients (P < 0.05). TSP and Hb levels showed significant (P < 0.01) decrease in OSMF patients as compared to smokeless tobacco chewers.

CONCLUSION

The elevation of immunoglobulin levels supports the concept of autoimmunity. The decrease in TSP and Hb suggests that nutritional deficiency plays a defined role in the occurrence as well as a further progression of OSMF.

Comparison of Immunohistochemical Expression of Antiapoptotic Protein Survivin in Normal Oral Mucosa, Oral Leukoplakia, and Oral Squamous Cell Carcinoma

Background. Oral squamous cell carcinoma is the sixth most frequent malignant tumor worldwide and the third most common cancers in developing countries. Oral leukoplakia is the best-known precursor lesion of oral squamous cell carcinoma. The aim of the present study was to compare immunohistochemical expression of antiapoptotic protein survivin in normal oral mucosa, oral leukoplakia, and oral squamous cell carcinoma. Method. Total 45 specimens of formalin fixed paraffin embedded tissue blocks, 15 in each of the following: normal oral mucosa, leukoplakia, and oral squamous cell carcinoma were used for the study. Immunohistochemical reaction for survivin protein was performed for the 4 µm thick histological sections taken on positively charged slides. Results. 20% normal mucosa cases, 53.33% cases of leukoplakia, and 80% of oral squamous cell carcinoma were found out to be survivin positive. One way ANOVA test indicated statistically significant difference of survivin expression between the three different groups (p < 0.001). Conclusion. A high incidence of survivin protein expression in oral epithelial dysplasia and squamous cell carcinoma samples indicate that survivin protein expression may be an early event in initiation and progression of oral squamous cell carcinoma.

Epigallocatechin-3-gallate suppresses cell proliferation and promotes apoptosis and autophagy in oral cancer SSC-4 cells

Epigallocatechin-3-gallate (EGCG) is the major bioactive component of green tea. Our experimental data indicated that EGCG treatment suppresses cell proliferation of SSC-4 human oral squamous cell carcinoma (OSCC), the effect being dose- and time-dependent. In parallel was observed the activation of apoptosis and autophagy, in response to EGCG exposure in SSC-4 cells. Treatment with EGCG activates the expression of the BAD, BAK, FAS, IGF1R, WNT11, and ZEB1 genes and inhibits CASP8, MYC, and TP53. All of these results suggest that EGCG has an excellent potential to become a therapeutic compound for patients with OSCC, by inducing tumor cell death via apoptosis and autophagy.

A Cytogenetic Study on the Efficacy of Chyawanprash Awaleha as an Antioxidant in Oral Premalignant Cancer

Background. Chyawanprash awaleha (Cp) is an Ayurvedic rasayana formulation and is used as a genoprotective agent. Objective. The present cytogenetic study has been done to investigate the efficacy of Cp against betel quid chewers suffering from oral precancerous lesions through satellite association (SA) assay. Materials and Methods. The frequency of SA was analyzed in 21 betel quid chewing oral precancerous lesions patients and then they were divided into 2 groups. Group 1 consisted of 15 patients, advised to quit betel quid chewing and fed with 20 gms of Cp, twice a day for three months. Group 2 consisted of 6 patients, who refused Cp feed but accepted to quit betel quid chewing. At the end of three months, both groups were assessed cytogenetically. Results. The frequency of SA was statistically significant in both groups, but an elevated mean difference was observed more in Group 1 than in Group 2. Conclusion. The study indicates that betel quid cessation reduces the effect of DNA damage in oral precancerous lesions. But the increased mean difference in SA in Group 1 compared to Group 2 clearly indicates that Cp can further minimize the genotoxic effect caused by mutagenic agents present in betel quid.

Caffeic acid reduces the viability and migration rate of oral carcinoma cells (SCC-25) exposed to low concentrations of ethanol

Alcohol increases the risk of carcinoma originated from oral epithelium, but the biological effects of ultra-low doses of ethanol on existing carcinoma cells in combination with natural substances are still unclear. A role for ethanol (EtOH), taken in small amounts as an ingredient of some beverages or mouthwashes to change the growth behavior of established squamous cell carcinoma, has still not been examined sufficiently. We designed an in vitro study to determine the effect of caffeic acid (CFA) on viability and migration ability of malignant oral epithelial keratinocytes, exposed to ultra-low concentrations (maximum 100 mmol/L) EtOH. MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-dimethyltetrazolium bromide) and LDH (lactate dehydrogenase) assays were used to assess the cytotoxic effect of EtOH/CFA and the viability of squamous carcinoma SCC-25 cells (ATCC CRL-1628, mobile part of the tongue). Tested EtOH concentrations were: 2.5, 5, 10, 25, 50, and 100 mmol/L, along with an equal CFA concentration of 50 μmol/L. Carcinoma cells’ migration was investigated by monolayer “wound” healing assay. We demonstrated that very low concentrations of EtOH ranging between 2.5 and 10 mmol/L may induce the viability of oral squamous cell carcinoma cells, while the results following addition of CFA reveal an antagonistic effect, attenuating pro-proliferative EtOH activity. The migration rate of oral squamous carcinoma cells can be significantly inhibited by the biological activity of caffeic acid.

Oral oncoprevention by phytochemicals - a systematic review disclosing the therapeutic dilemma

The aim of this article is to emphasize and focus on the preclinical and clinical update on phytochemicals and their role in prevention of oral carcinogenesis. Accordingly, the literature search was made following database: Embase, Medline, Science Citation index, NIH public access, pubmed and Cochrane Database of systematic reviews. Several internet websites were also searched to access publications from major phytochemical research sites and relevant information was obtained with regards to each plant chemical. The authors also spotted different list servers through wignet.com, Stanford cancer research etc: The data base search was made from the inception to 1988 and updated till 2013. A systematic method was obtained for literature search and data collection was critiqued. 60 articles were searched, among which there were only 6 systematic reviews on phytochemicals regarding oral carcinogenesis. Additional articles were obtained on phytochemicals and their mechanism of action in other cancers, which were regarded as background material. The studies done by various authors on each phytochemical has been briefly emphasized.

Biomarkers and chemopreventives in oral carcinogenesis and its prevention

Squamous cell carcinoma is the predominant type of oral malignancy and is a result of oral carcinogenesis. Oral carcinogenesis is a mutifactorial and complex process related to the sequential occurrence of alterations in genetic structures, promoting inhibitory or excitatory effects of the tumor oncogenes and gene suppressors, compromising the histophysiology of the division, differentiation and cell death; and therefore, methods to prevent, detect, or treat it in the best way is constantly being searched for. Biomarkers reveal the genetic and molecular changes related to early, intermediate and late endpoints in the process of oral carcinogenesis. Thereby, they are likely to not only refine our ability to predict the biologic course of oral cancer and distinguish individuals at high and/or low risk of oral cancer development; but, also they will also reveal the genetic and molecular changes related to various endpoints of oral carcinogenesis. Chemopreventives are chemicals of natural or synthetic origin, which reduce the incidence of fatal diseases such as cancer before clinical symptoms occur. Chemopreventives are agents whose curative capacity is defined with help of biomarkers, as the later determine the effectiveness and safety of chemopreventives.