Curcumin inhibits epithelial-mesenchymal transition in oral cancer cells via c-Met blockade

Microenvironment-based immunotherapy in oral cancer: a comprehensive review

Oral cancer, a prevalent form of head and neck malignancy, accounts for 4% of global cancer cases. The most common type, oral squamous cell carcinoma (OSCC), has a survival rate of about 50%. Even though emerging molecular therapies show promise for managing oral cancer, current treatments like surgery, radiotherapy, and chemotherapy have significant side effects. In addition, the complex tumor microenvironment (TME), involving the extracellular matrix (ECM) and cells like fibroblasts and stromal cells like immune cells, promotes tumor growth and inhibits immune responses, complicating treatment. Nonetheless, immunotherapy is crucial in cancer treatment, especially in oral cancers. Indeed, its effectiveness lies in targeting immune checkpoints such as PD-1 and CTLA-4 inhibitors, as well as monoclonal antibodies like pembrolizumab and cetuximab, adoptive cell transfer methods (including CAR-T cell therapy), cytokine therapy such as IL-2, and tumor vaccines. Thus, these interventions collectively regulate tumor proliferation and metastasis by targeting the TME through autocrine-paracrine signaling pathways. Immunotherapy indeed aims to stimulate the immune system, leveraging both innate and adaptive immunity to counteract cancer cell signals and promote tumor destruction. This review will explore how the TME controls tumor proliferation and metastasis via autocrine-paracrine signaling pathways. It will then detail the effectiveness of immunotherapy in oral cancers, focusing on immune checkpoints, targeted monoclonal antibodies, adoptive cell transfer, cytokine therapy, and tumor vaccines.

From cell lines to animal models: "plant- derived chemotherapeutics unlocking new frontiers against oral squamous cell carcinoma"-a comprehensive systematic review

BACKGROUND AND AIM

Despite progress in traditional treatment methods, the overall survival rate for oral squamous cell carcinoma (OSCC) remains limited. Consequently, it is essential to investigate alternative therapeutic strategies to enhance patient outcomes. This review highlights the potential role of plant extracts as chemo preventive agents in oral cancer treatment.

METHODS

A systematic review was conducted following PRISMA guidelines, involving an extensive literature search from databases such as PubMed, Scopus, Embase, Web of science, Cochrane and CINAHL which included studies from 2010 to 2024 that explored the anticancer potential of medicinal plants for OSCC treatment. Data extraction focused on plant species, parts used, extract type, active components, dosage, and cancer cell lines or animal models used. Risk of bias was assessed using the OHAT tool for animal studies and the ROBINS-I tool for in vitro studies.

RESULTS

A total of 12 in vitro and animal studies were included, examining plants such as Allium sativum (garlic), Crocus sativus (saffron), Curcuma longa (turmeric), Scutellariabaicalensis (Baikal skullcap), etc., These studies demonstrated that bioactive components like allicin, curcumin, and baicalin significantly inhibited OSCC cell proliferation and induced apoptosis. However, there was substantial variability in the dose concentrations required, ranging from 1 µg/mL for garlic extract to 50 mg/mL for saffron nanoparticles. The risk of bias assessment indicated that four studies had a moderate risk, while one had a low risk of bias, indicating methodological rigor.

CONCLUSION

Plant extracts such as Curcuma longa and Vitis vinifera present a promising, less toxic alternative for OSCC treatment, with the potential to be integrated into conventional chemotherapeutic regimens. While in-vitro and animal studies are encouraging, further clinical trials among humans are necessary to confirm their efficacy and safety in clinical settings.

Targeting epithelial-mesenchymal transition signaling pathways with Dietary Phytocompounds and repurposed drug combinations for overcoming drug resistance in various cancers

The epithelial-to-mesenchymal transition (EMT) is a crucial step in metastasis formation. It enhances the ability of cancer cells' to self-renew and initiate tumors, while also increasing resistance to apoptosis and chemotherapy. Among the signaling pathways a few signaling pathways such as Notch, TGF-beta, and Wnt-beta catenin are critically involved in the epithelial-to-mesenchymal transition (EMT) acquisition. Therefore, regulating EMT is a key strategy for controlling malignant cell behavior. This is done by interconnecting other signaling pathways in many cancer types. Although there is extensive preclinical evidence regarding EMT's function in the development of cancer, there is still a deficiency in clinical translation at the therapeutic level. Thus, there is a need for medications that are both highly effective and with low cytotoxic for modulating EMT transitions at ground level. Thus, this led to the study of the evaluation and efficiency of phytochemicals found in dietary sources of fruits and vegetables and also the combination of small molecular repurposed drugs that can enhance the effectiveness of traditional cancer treatments. This review summarises major EMT-associated pathways and their cross talks with their mechanistic insights and the role of different dietary phytochemicals (curcumin, ginger, fennel, black pepper, and clove) and their natural analogs and also repurposed drugs (metformin, statin, chloroquine, and vitamin D) which are commonly used in regulating EMT in various preclinical studies. This review also investigates the concept of low-toxicity and broad spectrum ("The Halifax Project") approach which can help for site targeting of several key pathways and their mechanism. We also discuss the mechanisms of action, models for our dietary phytochemicals, and repurposed drugs and their combinations used to identify potential anti-EMT activities. Additionally, we also analyzed existing literature and proposed new directions for accelerating the discovery of novel drug candidates that are safe to administer.

Targeting the Hippo and Rap1 signaling pathways: the anti-proliferative effects of curcumin in colorectal cancer cell lines

CRC has the third-highest cancer incidence and death. Many human cancers, including colorectal cancer, are connected to abnormal signaling pathway gene expression. Many human malignancies include Hippo and Rap1 signaling. This research examined curcumin's therapeutic effects on colorectal cancer cell lines' Hippo and Rap1 signaling pathway genes. The role of the above signaling pathways is considered in colorectal cancer development. No research has examined curcumin's influence on key genes in these pathways; thus, this work is meant to uncover its more precise mechanism. First, the gene expression omnibus database is queried to discover GSE8671, a dataset that contains differentially expressed genes associated in CRC formation. DAVID was used to discover the corporation of these genes and signaling pathways (Hippo and Rap1), and the cancer genome atlas (TCGA) database was utilized to select genes and assess their expression and biomarker potential. MTT, apoptosis, and quantitative PCR were used to assess whether curcumin is therapeutic for colorectal cancer cell lines. An in-silico analysis identified the dysregulation of several critical genes AXIN2, MYC, TEAD4, MET, LPAR1, and ADCY9 in colorectal cancer, highlighting their involvement in the Hippo and Rap1 signaling pathways. Experimental assessments, including MTT assays, apoptosis assays, and quantitative PCR (qPCR) analysis, demonstrated that the targeted modulation of these genes effectively inhibits cancer cell proliferation. Specifically, treatment with curcumin resulted in a significant reduction in cell viability in HT-29 and HCT-116 colorectal cancer cell lines, thereby facilitating apoptotic cell death. Furthermore, curcumin administration was associated with the upregulation of LPAR1 and ADCY9 gene expression, while concurrently downregulating AXIN2, MYC, TEAD4, and MET in both cell lines. This study reveals compelling evidence of curcumin's potent anticancer properties, highlighting its transformative influence on the Hippo and Rap1 signaling pathways within colorectal cancer cells. These findings not only underscore curcumin's potential as a therapeutic agent but also pave the way for innovative strategies in the fight against colorectal cancer.

Curcumin and its Analogues in Oral Squamous Cell Carcinoma: State-of-the-art and Therapeutic Potential

Oral Squamous Cell Carcinoma (OSCC) is the most common cancer arising from squamous epithelium in the oral cavity and is characterized by high aggressiveness and metastatic potential, which together with a late diagnosis results in a 5-year survival rate of only 50% of patients. The therapeutic options for OSCC management are limited and largely influenced by the cancer stage. While radical surgery can be curative in early stage of disease, most cases require adjuvant therapies, including chemotherapy and radiotherapy which, however, often achieve poor curative rates and are associated with important negative effects. Therefore, there is an urgent need to discover new alternative treatment strategies to improve patients' outcomes. Several medicinal herbs are being studied for their preventive or therapeutic effect in several diseases, including cancer. In particular, the Indian spice curcumin, largely used in oriental countries, has been studied as a chemopreventive or adjuvant agent for different malignancies. Indeed, curcumin is characterized by important biological properties, including antioxidant, anti-inflammatory, and anticancer effects, which could also be exploited in OSCC. However, due to its limited bioavailability and poor aqueous solubility, this review is focused on studies designing new synthetic analogues and developing novel types of curcumin delivery systems to improve its pharmacokinetic and biological properties. Thus, this review analyses the potential therapeutic role of curcumin in OSCC by providing an overview of current in vitro and in vivo studies demonstrating the beneficial effects of curcumin and its analogues in OSCC.

Application of Natural Medicinal Plants Active Ingredients in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is the most common malignant cancer of the head and neck, with high morbidity and mortality, ranking as the sixth most common cancer in the world. The treatment of OSCC is mainly radiotherapy, chemotherapy and surgery, however, the prognosis of patients is still poor and the recurrence rate is high. This paper reviews the range of effects of natural medicinal plant active ingredients (NMPAIs) on OSCC cancer, including the types of NMPAIs, anti-cancer mechanisms, involved signaling pathways, and clinical trials. The NMPAIs include terpenoids, phenols, flavonoids, glycosides, alkaloids, coumarins, and volatile oils. These active ingredients inhibit proliferation, induce apoptosis and autophagy, inhibit migration and invasion of OSCC cells, and regulate cancer immunity to exert anti-cancer effects. The mechanism involves signaling pathways such as mitogen-activated protein kinase, phosphatidylinositol 3 kinase/protein kinase B, nuclear factor kappa B, miR-22/WNT1/β-catenin and Nrf2/Keap1. Clinically, NMPAIs can inhibit the growth of OSCC, and the combined drug is more effective. Natural medicinal plants are promising candidates for the treatment of OSCC.

Phytochemicals in Cancer Chemoprevention: Preclinical and Clinical Studies

Phytochemicals, chemicals from plants, have garnered huge attention for their potential ability to prevent cancer. In vivo and preclinical models show that they do so often by affecting the hallmarks of cancer. Phytochemicals affect key pathways involved in the survival, genome maintenance, proliferation, senescence, and transendothelial migration of cancer cells. Some phytochemicals, namely antioxidants, can scavenge and quench reactive oxygen species (ROS) to prevent lipid peroxidation and DNA damage. They also trigger apoptosis by stopping the cell cycle at checkpoints to initiate the DNA damage response. Numerous in vitro and in vivo studies suggest that phytochemicals hinder cancer onset and progression by modifying major cell signaling pathways such as JAK/STAT, PI3K/Akt, Wnt, NF-kB, TGF-β, and MAPK. It is a well-known fact that the occurrence of cancer is in itself a very intricate process involving multiple mechanisms concurrently. Cancer prevention using phytochemicals is also an equally complex process that requires investigation and understanding of a myriad of processes going on in the cells and tissues. While many in vitro and preclinical studies have established that phytochemicals may be potential chemopreventive agents of cancer, their role in clinical randomized control trials needs to be established. This paper aims to shed light on the dynamics of chemoprevention using phytochemicals.

Hsa_circ_0136666 mediates the antitumor effect of curcumin in colorectal carcinoma by regulating CXCL1 via miR-1301-3p

BACKGROUND

This study investigate the anti-tumor effect of curcumin and whether its mediated by hsa_circ_0136666 through miR-1301-3p/CXCL1 in colorectal carcinoma (CRC). Through multiple experiments, we have drawn the conclusion that curcumin inhibited CRC development through the hsa_circ_0136666/miR-1301-3p/CXCL1 axis, hinting at a novel treatment option for curcumin to prevent CRC development.

AIM

To determine whether hsa_circ_0136666 involvement in curcumin-triggered CRC progression was mediated by sponging miR-1301-3p.

METHODS

Cell counting kit-8, colony-forming cell, 5-ethynyl-2'-deoxyuridine, and flow cytometry assays were carried out to determine cell proliferation, apoptosis, and cell cycle progression. Real-time quantitative polymerase chain reaction quantified hsa_circ_0136666, miR-1301-3p, and chemokine (C-X-C motif) ligand 1 (CXCL1), and western blot analysis determined CXCL1, B-cell lymphoma-2 (Bcl-2), and Bcl-2 related X protein (Bax) protein levels. CircBank or starbase software was first used for the prediction of miR-1301-3p binding with hsa_circ_0136666 and CXCL1, followed by RNA pull-down, RNA immunoprecipitation, and dual-luciferase reporter assay validation. In vivo experiments were implemented in a murine xenograft model.

RESULTS

Curcumin blocked CRC cell proliferation but boosted apoptosis. Moreover, elevated hsa_circ_0136666 Levels were observed in CRC cells, which were reduced by curcumin. In vitro, hsa_circ_0136666 overexpression abolished the antitumor activity of CRC cells. Mechanical analysis revealed the ability of hsa_circ_0136666 to sponge miR-1301-3p to modulate CXCL1 levels.

CONCLUSION

Curcumin inhibited CRC development through the hsa_circ_0136666/miR-1301-3p/CXCL1 axis, hinting at a novel treatment option for curcumin to prevent CRC development.

Radiation modulates expression and related activities of c-Met protein in oral tongue squamous cell carcinoma cell lines

OBJECTIVES

c-Met, a receptor tyrosine kinase, is involved in the growth, invasion and metastasis of a variety of cancers. In a set of cell lines from several solid tumors, a five-fold increase in c-Met expression after irradiation has been reported. This study aimed to assess if c-Met is likewise abundantly expressed in oral tongue squamous cell carcinoma (OTSCC) upon exposure to irradiation, followed by a Met-induced biological response.

MATERIALS AND METHODS

Six OTSCC cell lines were exposed to gamma radiation doses of 2, 4, and 6 Gray. The changes in c-Met protein levels were assessed by western blot and flow cytometry. c-Met gene expression, cell migration, proliferation and cell cycle assays were performed as phenotypic readouts.

RESULTS

Irradiation resulted in upregulation of c.Met in all cell lines with different time kinetics. On average the cells displayed minimal c-Met expression on their surface ranging from 5 to 30% of total protein. Abrupt downregulation of c-Met surface expression occurred one hour after radiation but recovered 48 h post-radiation. Intracellularly, the highest level of expression was found on day 5 after radiation exposure. Irradiation induced aggressive invasive potential of the cells as determined in cell migration assays, particularly in cell lines with the highest c-Met expression.

CONCLUSIONS

These results provide novel insights into both intracellular and extracellular dynamics of c-Met expression profiles upon irradiation of OTSCC cells in vitro. It might also suggest that radiation enhances cell migration, indicative of invasiveness, through c-Met up-regulation, at least for certain types of OTSCC cells.

Therapeutic potential of curcumin and its nanoformulations for treating oral cancer

The global incidence of oral cancer has steadily increased in recent years and is associated with high morbidity and mortality. Oral cancer is the most common cancer in the head and neck region, and is predominantly of epithelial origin (i.e. squamous cell carcinoma). Oral cancer treatment modalities mainly include surgery with or without radiotherapy and chemotherapy. Though proven effective, chemotherapy has significant adverse effects with possibilities of tumor resistance to anticancer drugs and recurrence. Thus, there is an imperative need to identify suitable anticancer therapies that are highly precise with minimal side effects and to make oral cancer treatment effective and safer. Among the available adjuvant therapies is curcumin, a plant polyphenol isolated from the rhizome of the turmeric plant Curcuma longa. Curcumin has been demonstrated to have anti-infectious, antioxidant, anti-inflammatory, and anticarcinogenic properties. Curcumin has poor bioavailability, which has been overcome by its various analogues and nanoformulations, such as nanoparticles, liposome complexes, micelles, and phospholipid complexes. Studies have shown that the anticancer effects of curcumin are mediated by its action on multiple molecular targets, including activator protein 1, protein kinase B (Akt), nuclear factor κ-light-chain-enhancer of activated B cells, mitogen-activated protein kinase, epidermal growth factor receptor (EGFR) expression, and EGFR downstream signaling pathways. These targets play important roles in oral cancer pathogenesis, thereby making curcumin a promising adjuvant treatment modality. This review aims to summarize the different novel formulations of curcumin and their role in the treatment of oral cancer.

Effects of curcumin on oral cancer at molecular level: A systematic review

This systematic review mainly focuses on the effects of curcumin on oral cancer cells at the molecular level and summarizes the results of the studies. We searched and analyzed various databases such as Pub Med, ProQuest, Google Scholar, Science Direct, and Scopus. Searches were conducted from 2006 to 2021. This systematic review evaluated various effects of curcumin on oral cancer at the molecular level. All the studies related to the effects of curcumin on oral cancer, both in-vivo and in-vitro, were included. After abstract and text screening a total of 13 articles were finally selected for the study based on the inclusion and exclusion criteria. All most all the included studies reported that after treating the cell lines with curcumin there is a reduction in cell proliferation and cell growth, analyzed using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. Curcumin also induces S phase cell cycle arrest and also prevents Tregs migration. The curcumin reverses the process of epithelial mesenchymal transition (EMT) back to mesenchymal epithelial transition (MET). From this review, it is concluded that curcumin inhibited proliferation, migration, invasion, and metastasis, and induced apoptosis via modulating multiple signaling pathways in oral cancer cell lines. But further clinical trials are needed for a detailed evaluation of the effects of curcumin on patients with oral cancer.

Curcumin Reprograms TAMs from a Protumor Phenotype towards an Antitumor Phenotype via Inhibiting MAO-A/STAT6 Pathway

M1 phenotype macrophages have anticancer characteristics, whereas M2 phenotype macrophages promote tumor growth and metastasis. A higher M1/M2 ratio, therefore, has a beneficial effect on the tumor immune microenvironment, thereby inhibiting tumor growth. The natural alkaloid curcumin is found to have anticancer properties. However, the mechanism remains unclear. In this study, a cell co-culture system and M2 macrophage model were used to evaluate the effects of curcumin on tumor-associated macrophage (TAM) phenotypes. Our results demonstrate that curcumin reprogrammed the M2 macrophages by reducing the level of anti-inflammatory cytokines (TGF-β, Arg-1, and IL-10) and an M2 surface marker (CD206) induced by Cal27 cells or IL-4, as well as upregulating proinflammatory cytokines (TNF-α, iNOS, and IL-6) and an M1 surface marker (CD86). The in vitro assays suggested that curcumin treatment suppressed the migration and invasion of the Cal27 cells induced by the M2-like macrophages. Mechanistically, the repolarization of TAMs may be attributed to the inhibition of monoamine oxidase A (MAO-A)/STAT6 signaling after curcumin treatment. Collectively, our results show that the anticancer effects of curcumin could be explained by reprogramming TAMs from a protumor phenotype towards an antitumor phenotype.

Procaine Abrogates the Epithelial-Mesenchymal Transition Process through Modulating c-Met Phosphorylation in Hepatocellular Carcinoma

Simple Summary

Epithelial-mesenchymal transition (EMT) is a vital process that leads to the dissemination of tumor cells to distant organs and promotes cancer progression. Aberrant activation of c-Met has been positively correlated with tumor metastasis in hepatocellular carcinoma (HCC). In this report, we have demonstrated the suppressive effect of procaine on the EMT process through the blockade of the c-Met signaling pathway. Procaine downregulated mesenchymal markers and upregulated epithelial markers. Functionally, procaine abrogated cellular migration and invasion. Moreover, procaine suppressed c-Met and its downstream signaling events in HCC models. We report that procaine can function as a novel inhibitor of the EMT process and c-Met-dependent signaling cascades. These results support the consideration of procaine being tested as a potential anti-metastatic agent.

Abstract

EMT is a critical cellular phenomenon that promotes tumor invasion and metastasis. Procaine is a local anesthetic agent used in oral surgeries and as an inhibitor of DNA methylation in some types of cancers. In this study, we have investigated whether procaine can inhibit the EMT process in HCC cells and the preclinical model. Procaine suppressed the expression of diverse mesenchymal markers but induced the levels of epithelial markers such as E-cadherin and occludin in HGF-stimulated cells. Procaine also significantly reduced the invasion and migration of HCC cells. Moreover, procaine inhibited HGF-induced c-Met and its downstream oncogenic pathways, such as PI3K/Akt/mTOR and MEK/ERK. Additionally, procaine decreased the tumor burden in the HCC mouse model and abrogated lung metastasis. Overall, our study suggests that procaine may inhibit the EMT process through the modulation of a c-Met signaling pathway.

Tumor microenvironment and immunotherapy of oral cancer

Oral cancer is one of the most common malignant tumors of the head and neck, not only affects the appearance, but also affects eating and even endangers life. The clinical treatments of oral cancer mainly include surgery, radiotherapy, and chemotherapy. However, unsatisfactory therapeutic effect and toxic side effects are still the main problems in clinical treatment. Tumor microenvironment (TME) is not only closely related to the occurrence, growth, and metastasis of tumor but also works in the diagnosis, prevention, and treatment of tumor and prognosis. Future studies should continue to investigate the relationship of TME and oral cancer therapy. This purpose of this review was to analyze the characteristics of oral cancer microenvironment, summarize the traditional oral cancer therapy and immunotherapy strategies, and finally prospect the development prospects of oral cancer immunotherapy. Immunotherapy targeting tumor microenvironment is expected to provide a new strategy for clinical treatment of oral cancer.

Effects and Mechanisms of Curcumin for the Prevention and Management of Cancers: An Updated Review

Cancer is the leading cause of death in the world. Curcumin is the main ingredient in turmeric (Curcuma longa L.), and is widely used in the food industry. It shows anticancer properties on different types of cancers, and the underlying mechanisms of action include inhibiting cell proliferation, suppressing invasion and migration, promoting cell apoptosis, inducing autophagy, decreasing cancer stemness, increasing reactive oxygen species production, reducing inflammation, triggering ferroptosis, regulating gut microbiota, and adjuvant therapy. In addition, the anticancer action of curcumin is demonstrated in clinical trials. Moreover, the poor water solubility and low bioavailability of curcumin can be improved by a variety of nanotechnologies, which will promote its clinical effects. Furthermore, although curcumin shows some adverse effects, such as diarrhea and nausea, it is generally safe and tolerable. This paper is an updated review of the prevention and management of cancers by curcumin with a special attention to its mechanisms of action.

Curcuminoids as Modulators of EMT in Invasive Cancers: A Review of Molecular Targets With the Contribution of Malignant Mesothelioma Studies

Curcuminoids, which include natural acyclic diarylheptanoids and the synthetic analogs of curcumin, have considerable potential for fighting against all the characteristics of invasive cancers. The epithelial-to-mesenchymal transition (EMT) is a fundamental process for embryonic morphogenesis, however, the last decade has confirmed it orchestrates many features of cancer invasiveness, such as tumor cell stemness, metabolic rewiring, and drug resistance. A wealth of studies has revealed EMT in cancer is in fact driven by an increasing number of parameters, and thus understanding its complexity has now become a cornerstone for defining future therapeutic strategies dealing with cancer progression and metastasis. A specificity of curcuminoids is their ability to target multiple molecular targets, modulate several signaling pathways, modify tumor microenvironments and enhance the host’s immune response. Although the effects of curcumin on these various parameters have been the subject of many reviews, the role of curcuminoids against EMT in the context of cancer have never been reviewed so far. This review first provides an updated overview of all EMT drivers, including signaling pathways, transcription factors, non-coding RNAs (ncRNAs) and tumor microenvironment components, with a special focus on the most recent findings. Secondly, for each of these drivers the effects of curcumin/curcuminoids on specific molecular targets are analyzed. Finally, we address some common findings observed between data reported in the literature and the results of investigations we conducted on experimental malignant mesothelioma, a model of invasive cancer representing a useful tool for studies on EMT and cancer.

Receptor Tyrosine Kinases and Their Signaling Pathways as Therapeutic Targets of Curcumin in Cancer

Receptor tyrosine kinases (RTKs) are transmembrane cell-surface proteins that act as signal transducers. They regulate essential cellular processes like proliferation, apoptosis, differentiation and metabolism. RTK alteration occurs in a broad spectrum of cancers, emphasising its crucial role in cancer progression and as a suitable therapeutic target. The use of small molecule RTK inhibitors however, has been crippled by the emergence of resistance, highlighting the need for a pleiotropic anti-cancer agent that can replace or be used in combination with existing pharmacological agents to enhance treatment efficacy. Curcumin is an attractive therapeutic agent mainly due to its potent anti-cancer effects, extensive range of targets and minimal toxicity. Out of the numerous documented targets of curcumin, RTKs appear to be one of the main nodes of curcumin-mediated inhibition. Many studies have found that curcumin influences RTK activation and their downstream signaling pathways resulting in increased apoptosis, decreased proliferation and decreased migration in cancer both in vitro and in vivo. This review focused on how curcumin exhibits anti-cancer effects through inhibition of RTKs and downstream signaling pathways like the MAPK, PI3K/Akt, JAK/STAT, and NF-κB pathways. Combination studies of curcumin and RTK inhibitors were also analysed with emphasis on their common molecular targets.

Plant-Based Antioxidant Extracts and Compounds in the Management of Oral Cancer

Oral cancer continues to be a leading cause of death worldwide, and its prevalence is particularly high in developing countries, where people chew tobacco and betel nut on a regular basis. Radiation-, chemo-, targeted-, immuno-, and hormone-based therapies along with surgery are commonly used as part of a treatment plan. However, these treatments frequently result in various unwanted short- to long-term side effects. As a result, there is an urgent need to develop treatment options for oral cancer that have little or no adverse effects. Numerous bioactive compounds derived from various plants have recently attracted attention as therapeutic options for cancer treatment. Antioxidants found in medicinal plants, such as vitamins E, C, and A, reduce damage to the mucosa by neutralizing free radicals found in various oral mucosal lesions. Phytochemicals found in medicinal plants have the potential to modulate cellular signalling pathways that alter the cellular defence mechanisms to protect normal cells from reactive oxygen species (ROS) and induce apoptosis in cancer cells. This review aims to provide a comprehensive overview of various medicinal plants and phytoconstituents that have shown the potential to be used as oral cancer therapeutics.

Antimetastatic Effects of Curcumin in Oral and Gastrointestinal Cancers

Gastrointestinal (GI) cancers are known as frequently occurred solid malignant tumors that can cause the high rate mortality in the world. Metastasis is a significant destructive feature of tumoral cells, which directly correlates with decreased prognosis and survival. Curcumin, which is found in turmeric, has been identified as a potent therapeutic natural bioactive compound (Curcuma longa). It has been traditionally applied for centuries to treat different diseases, and it has shown efficacy for its anticancer properties. Numerous studies have revealed that curcumin inhibits migration and metastasis of GI cancer cells by modulating various genes and proteins, i.e., growth factors, inflammatory cytokines and their receptors, different types of enzymes, caspases, cell adhesion molecules, and cell cycle proteins. Herein, we summarized the antimetastatic effects of curcumin in GI cancers, including pancreatic cancer, gastric cancer, colorectal cancer, oral cancer, and esophageal cancer.

Tumor Microenvironment: Involved Factors and Signaling Pathways in Epithelial-Mesenchymal Transition

Context: Metastasis is a main cause of death in patients with cancer, whereby tumor cells withdraw from the primary site of the tumor mass and produce secondary tumor mass in new sites. Primary tumor cells depart collectively and individually to invade closed and distant sites. Evidence Acquisition: This review considers TME-derived factors that actuate signaling pathways to induce epithelial-mesenchymal transition (EMT). National Center for Biotechnology Information (NCBI) was the main resource. Google Scholar and Scopus were other databases for finding articles. Keywords that were inserted into the search box of databases to identify related articles were ‘metastasis’, ‘invasion’, ‘epithelial-mesenchymal transition’, ‘EMT’, ‘tumor microenvironment’, ‘TME’, ‘TME cells’, and ‘signaling pathway in EMT’. Titles and abstracts of the articles were studied to choose the right articles. Finally, 107 articles were selected to study in detail and use as references. Results: EMT is a type of metastasis that deprives epithelial single-cells of their characteristic features and acquires mesenchymal features facilitating the departure from the primary tumor mass. During EMT, cell-adhesion and apical-basal polarity rapture and cells obtain movement capability. The tumor microenvironment (TME) leads EMT through secretion factors and signaling pathways. As a result of activating these pathways, transcription factors that abolish epithelial gene expressions and augment mesenchymal gene expression are induced. Conclusions: In this review, recent research published in TME and EMT fields were highlighted and critically appraised. Effect of factors-derived TME cells on EMT were manifested that propose favorite targets for a therapeutic goal to inhibit metastasis. However, data about the effect of the combination of TME cells on metastasis have a small part in the literature.

Drug Delivery (Nano)Platforms for Oral and Dental Applications: Tissue Regeneration, Infection Control, and Cancer Management

The oral cavity and oropharynx are complex environments that are susceptible to physical, chemical, and microbiological insults. They are also common sites for pathological and cancerous changes. The effectiveness of conventional locally-administered medications against diseases affecting these oral milieus may be compromised by constant salivary flow. For systemically-administered medications, drug resistance and adverse side-effects are issues that need to be resolved. New strategies for drug delivery have been investigated over the last decade to overcome these obstacles. Synthesis of nanoparticle-containing agents that promote healing represents a quantum leap in ensuring safe, efficient drug delivery to the affected tissues. Micro/nanoencapsulants with unique structures and properties function as more favorable drug-release platforms than conventional treatment approaches. The present review provides an overview of newly-developed nanocarriers and discusses their potential applications and limitations in various fields of dentistry and oral medicine.