Immunohistochemical assessment of Viadent-associated leukoplakia

Molecular targets and anticancer potential of sanguinarine-a benzophenanthridine alkaloid

BACKGROUND

Cancer is an enormous global health burden, and should be effectively addressed with better therapeutic strategies. Currently, over 60% of the clinically approved anticancer agents are either directly isolated from natural sources or are modified from natural lead molecules. Sanguinarine (SNG), a quaternary benzophenanthridine alkaloid has gained increasing attention in recent years as a potential anticancer agent.

PURPOSE

There is a large untapped source of phytochemical-based anticancer agents remaining to be explored. This review article aims to recapitulate different anticancer properties of SNG, and describes some of the molecular targets involved in exerting its effect. It also depicts the pharmacokinetic and toxicological properties of SNG, two parameters important in determining the druggability of a molecule.

METHODS

Numerous in vivo and in vitro published studies have signified the anticancer properties of SNG. In order to collate and decipher these properties, an extensive literature search was conducted in PubMed, ScienceDirect, and Scopus using keywords followed by the evaluation of the relevant articles where the relevant reports are integrated and analyzed.

RESULTS

Apart from inducing cell death, SNG inhibits pro-tumorigenic processes such as invasion, angiogenesis, and metastasis in different cancers. Moreover, SNG has been shown to synergistically enhance the sensitivity of several chemotherapeutic agents and is effective against a variety of multi-drug resistant cancers.

Carcinogenic potential of sanguinarine, a phytochemical used in 'therapeutic' black salve and mouthwash

Black salves are escharotic skin cancer therapies in clinical use since the mid 19th century. Sanguinaria canadensis, a major ingredient of black salve formulations, contains a number of bioactive phytochemicals including the alkaloid sanguinarine. Despite its prolonged history of clinical use, conflicting experimental results have prevented the carcinogenic potential of sanguinarine from being definitively determined. Sanguinarine has a molecular structure similar to known polyaromatic hydrocarbon carcinogens and is a DNA intercalator. Sanguinarine also generates oxidative and endoplasmic reticulum stress resulting in the unfolded protein response and the formation of 8-hydroxyguanine genetic lesions. Sanguinarine has been the subject of contradictory in vitro and in vivo genotoxicity and murine carcinogenesis test results that have delayed its carcinogenic classification. Despite this, epidemiological studies have linked mouthwash that contains sanguinarine with the development of oral leukoplakia. Sanguinarine is also proposed as an aetiological agent in gallbladder carcinoma. This literature review investigates the carcinogenic potential of sanguinarine. Reasons for contradictory genotoxicity and carcinogenesis results are explored, knowledge gaps identified and a strategy for determining the carcinogenic potential of sanguinarine especialy relating to black salve are discussed. As patients continue to apply black salve, especially to skin regions suffering from field cancerization and skin malignancies, an understanding of the genotoxic and carcinogenic potential of sanguinarine is of urgent clinical relevance.

Expression of Cell Cycle-associated Proteins p53, pRb, p16, p27, and Correlation With Survival: A Comparative Study on Oral Squamous Cell Carcinoma and Verrucous Carcinoma

Verrucous carcinoma (VC) is a well-differentiated form of squamous cell carcinoma (SCC) with better prognosis. Differences in molecular pathogenesis between the 2 have not been well-characterized. We conducted this study to evaluate immunohistochemical expression of cell-cycle regulatory proteins p53, pRb, p16, and p27 in SCC and VC, compare the expression in these 2 neoplasms, and assess if these markers have any diagnostic or prognostic value. Sixty cases of SCC with and without lymph node metastasis and 31 cases of VC were studied. Immunohistochemical analysis for p53, pRb, p16, and p27 was performed and the results were analyzed. SCC was most frequent in tongue (52%), whereas VC in buccal mucosa (81%). Mean age of SCC patients was significantly lower than in VC. Majority of SCCs were in stage III and IV (63%), whereas VCs were in stage I and II (84%). p53 immunopositivity was more frequent in SCC (65%) than in VC (23%) (P≤0.001). VC had lower p53 as compared with well-differentiated SCC and SCC without lymph node metastasis. No significant difference was seen in pRb, p16, and p27 expression. Disease-free survival (DFS) at 1 year for SCC was 57% whereas it was 80% for VC (P=0.02). DFS and overall survival of SCC correlated with nodal status and stage; cell-cycle-associated protein expression had no association with DFS. To conclude, p53 immunoexpression differs in SCC and VC, suggesting different pathogenesis, and it may have some utility as an adjunct to morphology to differentiate between the 2. Expression of cell-cycle-associated proteins does not influence survival in SCC.

Antitumor effects of the benzophenanthridine alkaloid sanguinarine: Evidence and perspectives

Historically, natural products have represented a significant source of anticancer agents, with plant-derived drugs becoming increasingly explored. In particular, sanguinarine is a benzophenanthridine alkaloid obtained from the root of Sanguinaria canadensis, and from other poppy Fumaria species, with recognized anti-microbial, anti-oxidant and anti-inflammatory properties. Recently, increasing evidence that sanguinarine exibits anticancer potential through its capability of inducing apoptosis and/or antiproliferative effects on tumor cells, has been proved. Moreover, its antitumor seems to be due not only to its pro-apoptotic and inhibitory effects on tumor growth, but also to its antiangiogenic and anti-invasive properties. Although the precise mechanisms underlying the antitumor activity of this compound remain not fully understood, in this review we will focus on the most recent findings about the cellular and molecular pathways affected by sanguinarine, together with the rationale of its potential application in clinic. The complex of data currently available suggest the potential application of sanguinarine as an adjuvant in the therapy of cancer, but further pre-clinical studies are needed before such an antitumor strategy can be effectively translated in the clinical practice.

Rise and fall of oral health products with Canadian bloodroot extract

The rhizome of Sanguinaria canadensis (SC, bloodroot) contains an active principle with antimicrobial, antiinflammatory, antioxidative and immunomodulatory effects. For this reason SC extract has been added to toothpastes and mouthwashes in various concentrations. When tested separately, neither the toothpastes nor the mouthwashes with SC extract had any demonstrable clinical effectiveness against dental plaque and gingivitis. Although using them together twice a day seemed more effective than using placebo, more recent studies have shown conflicting results. Preclinical safety studies up to 2000, which did not include studies longer than 6 months, were thought not to indicate any appreciable potential for harm - to the oral mucosa in particular. In 2003, the FDA Subcommittee on Oral Health Care Drug Products for Over-the-Counter Human Use concluded from a review that using SC-containing products is safe. However, for reasons unknown, the review failed to consider publications between 1999 and 2001 that suggested a possible link between the use of SC-containing products and the pre-neoplastic lesion, leukoplakia. As it happened, bloodroot had already been removed (in 2001) from the formula of one of the most widely used products in question and the brand has since then disappeared altogether from the worldwide market.

Bloodroot (Sanguinaria canadensis L., Papaveraceae) Enhances Proliferation and Cytokine Production by Human Peripheral Blood Mononuclear Cells in an In Vitro Model

Previous studies have suggested that phytomedicinal preparations from bloodroot (Sanguinaria canadensis L.) may harbor immunomodulatory properties. The purpose of this investigation was to determine the effects of alcohol tinctures and water infusions generated from bloodroot flowers, leaves, rhizomes, and roots on human peripheral blood mononuclear cell (PBMC) cytokine production and proliferation in vitro. PBMCs were collected from 16 healthy young adults and cultured with bloodroot extracts or respective controls for interleukins-1β, -2, -8, -10, interferon-γ, and tumor necrosis factor. Proliferative capabilities of both PBMCs and K562 cells (an immortalized human myelogenous leukemia cell line) following extract treatment were determined. High-pressure liquid chromatography was used to quantify berberine, chelerythrine, and sanguinarine in the extracts and to correlate extract composition with observed effects. Overall, infusions demonstrated greater immunomodulatory capabilities than tinctures, and flower- and root-based extracts showed greater immunomodulatory properties than leaf- or rhizome-based extracts (some effects seen with root-based extracts may be due to endotoxin). Several extracts were able to augment PBMC proliferation and diminish K562 proliferation, suggesting a selective anti-carcinogenic activity. The rhizome alcohol tincture had a markedly stronger effect against K562 cells than other extracts. Chelerythrine, sanguinarine, and endotoxin (but not berberine) sometimes correlated with observed effects. The in vitro activities demonstrated here suggest bloodroot extracts may have potential as therapeutic immunomodulators.

Sanguinarine cytotoxicity on mouse melanoma K1735-M2 cells--nuclear vs. mitochondrial effects

Sanguinarine (SANG) is an alkaloid recognized to have anti-proliferative activity against various human tumour cell lines. No data is available on the susceptibility of advanced malignant melanoma to SANG, although this disease has a very poor prognosis if not detected in time due to the resistance to conventional chemotherapy. The present work was designed to study the nuclear and mitochondrial involvement in the pro-apoptotic effect of SANG in an invasive mouse melanoma cell line. The results obtained show that SANG is primarily accumulated by the cell nuclei, causing inhibition of cell proliferation and inducing cell death, as confirmed by an increase in sub-G1 peaks. At low concentrations, SANG induces mitochondrial depolarization in a sub-population of melanoma cells, which also generally displayed strong nuclear labelling of phosphorylated histone H2AX. Western blotting revealed an increase in p53, but not Bax protein, in both whole-cell extracts and in mitochondrial fractions. Isolated hepatic mitochondrial fractions revealed that SANG affects the mitochondrial respiratory chain, and has dual effects on mitochondrial calcium loading capacity. We suggest that SANG is able to induce apoptosis in metastatic melanoma cells. The knowledge of mitochondrial vs. nuclear effects of SANG is important in the development of this promising compound for clinical use against aggressive melanoma.

Sanguinarine

Sanguinarine is an alkaloid found in many medicinal plants. It has diverse biological activities, including modulation of nuclear factor-kappaB and of several enzymes. It is also known to induce apoptosis, perturb microtubules, and to have antimicrobial effects. This article reviews its cardiovascular properties, including hypotensive, antiplatelet, and positive inotropic effects. Its pharmacokinetics, and toxicology, including its carcinogenic potential, are also discussed. Further pharmacological and toxicological studies with sanguinarine are needed before its therapeutic use can be considered.

Sanguinarine causes DNA damage and p53-independent cell death in human colon cancer cell lines

The benzophenanthridine alkaloid sanguinarine has antimicrobial and possibly anticancer properties but it is not clear to what extent these activities involve DNA damage. Thus, we studied its ability to cause DNA single and double strand breaks, as well as increased levels of 8-oxodeoxyguanosine, in human colon cancer cells and found DNA damage consistent with oxidation. Since the tumor suppressor p53 is frequently involved in inducing apoptosis following DNA damage we investigated the effect of sanguinarine in wild type, p53-mutant and p53-null colon cancer cell lines. We found them to be equally sensitive to this plant compound, indicating that cell death is not mediated by p53 in this case. In addition, our observation that apoptosis induced by sanguinarine is initiated very rapidly raised the question whether there is enough time for cellular signaling in response to DNA damage. Moreover, the abundance of double strand breaks is not consistent with only oxidative damage to DNA. We conclude that the majority of DNA double strand breaks in sanguinarine-treated cells are likely the result, rather than the cause, of apoptotic cell death and that apoptosis induced by sanguinarine is independent of p53 and most likely independent of DNA damage.