An Update on the Role of Dietary Phytochemicals in Human Skin Cancer: New Insights into Molecular Mechanisms

Spice-Derived Phenolic Compounds: Potential for Skin Cancer Prevention and Therapy

Skin cancer is a condition characterized by the abnormal growth of skin cells, primarily caused by exposure to ultraviolet (UV) radiation from the sun or artificial sources like tanning beds. Different types of skin cancer include melanoma, basal cell carcinoma, and squamous cell carcinoma. Despite the advancements in targeted therapies, there is still a need for a safer, highly efficient approach to preventing and treating cutaneous malignancies. Spices have a rich history dating back thousands of years and are renowned for their ability to enhance the flavor, taste, and color of food. Derived from various plant parts like seeds, fruits, bark, roots, or flowers, spices are important culinary ingredients. However, their value extends beyond the culinary realm. Some spices contain bioactive compounds, including phenolic compounds, which are known for their significant biological effects. These compounds have attracted attention in scientific research due to their potential health benefits, including their possible role in disease prevention and treatment, such as cancer. This review focuses on examining the potential of spice-derived phenolic compounds as preventive or therapeutic agents for managing skin cancers. By compiling and analyzing the available knowledge, this review aims to provide insights that can guide future research in identifying new anticancer phytochemicals and uncovering additional mechanisms for combating skin cancer.

Pathways Affected by Falcarinol-Type Polyacetylenes and Implications for Their Anti-Inflammatory Function and Potential in Cancer Chemoprevention

Polyacetylene phytochemicals are emerging as potentially responsible for the chemoprotective effects of consuming apiaceous vegetables. There is some evidence suggesting that polyacetylenes (PAs) impact carcinogenesis by influencing a wide variety of signalling pathways, which are important in regulating inflammation, apoptosis, cell cycle regulation, etc. Studies have shown a correlation between human dietary intake of PA-rich vegetables with a reduced risk of inflammation and cancer. PA supplementation can influence cell growth, gene expression and immunological responses, and has been shown to reduce the tumour number in rat and mouse models. Cancer chemoprevention by dietary PAs involves several mechanisms, including effects on inflammatory cytokines, the NF-κB pathway, antioxidant response elements, unfolded protein response (UPR) pathway, growth factor signalling, cell cycle progression and apoptosis. This review summarises the published research on falcarinol-type PA compounds and their mechanisms of action regarding cancer chemoprevention and also identifies some gaps in our current understanding of the health benefits of these PAs.

An update on clinical trials for chemoprevention of human skin cancer

The pathophysiology of skin cancer is complex, with multiple factors contributing to its development. The proactive treatment of skin cancer has been investigated in the form of chemoprevention of cutaneous malignancies in clinical trials. Chemoprevention is the use of natural or pharmacologic agents that prevent or reverse skin cancer development. Multiple trials have arisen over the past decades to explore the efficacy of specific agents to halt the progression of UV radiation damage. This comprehensive review article aims to assess clinical trials performed with chemopreventive agents for melanoma and nonmelanoma skin cancers. The following compounds were most often used in these trials: nicotinamide, retinoids, polyphenolic antioxidants, COX-2 selective inhibitors, non-steroidal anti-inflammatory drugs, difluoromethylornithine, and 5-fluorouracil. Many agents show promise in their ability to prevent nonmelanoma skin cancer formation, with few melanoma trials demonstrating efficacy. The chemoprevention efforts aimed at skin cancer are complex; current and future trials will be instrumental in identifying therapeutic agents that pose efficacy in halting cancer development and assessing whether long-term administration is tolerable.

Natural phytochemicals prevent side effects in BRCA-mutated ovarian cancer and PARP inhibitor treatment

Ovarian cancer is among the most common malignant tumors in gynecology and is characterized by insidious onset, poor differentiation, high malignancy, and a high recurrence rate. Numerous studies have shown that poly ADP-ribose polymerase (PARP) inhibitors can improve progression-free survival (PFS) in patients with BRCA-mutated ovarian cancer. With the widespread use of BRCA mutation and PARP inhibitor (PARPi) combination therapy, the side effects associated with BRCA mutation and PARPi have garnered attention worldwide. Mutations in the BRCA gene increase KEAP1-NRF2 ubiquitination and reduce Nrf2 content and cellular antioxidant capacity, which subsequently produces side effects such as cardiovascular endothelial damage and atherosclerosis. PARPi has hematologic toxicity, producing thrombocytopenia, fatigue, nausea, and vomiting. These side effects not only reduce patients' quality of life, but also affect their survival. Studies have shown that natural phytochemicals, a class of compounds with antitumor potential, can effectively prevent and treat the side effects of chemotherapy. Herein, we reviewed the role of natural phytochemicals in disease prevention and treatment in recent years, including sulforaphane, lycopene, catechin, and curcumin, and found that these phytochemicals have significant alleviating effects on atherosclerosis, nausea, and vomiting. Moreover, these mechanisms of action significantly correlated with the side-effect-producing mechanisms of BRCA mutations and PARPi. In conclusion, natural phytochemicals may be effective in alleviating the side effects of BRCA mutant ovarian cancer cells and PARP inhibitors.

Cornelian Cherry (Cornus mas L.) Extracts Exert Cytotoxicity in Two Selected Melanoma Cell Lines—A Factorial Analysis of Time-Dependent Alterations in Values Obtained with SRB and MTT Assays

Despite the fact that phytochemicals of Cornaceae species have long been discussed as possible auxiliary agents in contemporary treatment, the insights on their properties remain relatively scarce. This study focuses on Cornus mas L. (Cornelian cherry), the extracts of which are reported to exert a pleiotropic effect shown in both in vivo and in vitro studies. This study aimed to explore the cytotoxic effect of extracts from fruits of red (Cornus mas L. ‘Podolski’) and yellow (Cornus mas L. ‘Yantarnyi’ and ‘Flava’) Cornelian cherries on two melanoma cell lines (A375 and MeWo). The extracts were characterized in the context of the concentration of bioactive compounds of antioxidative properties. Cytotoxicity was investigated with the use of the following two assays: SRB and MTT. An additional, alternative protocol for the SRB assay was used in this study so as to account for possible bias. Cytotoxicity was assessed as a difference in the whole time series of cell viability, instead of analyzing differences in raw values (often found in the literature). Both extracts from Cornus mas L. induced cytotoxicity in both A375 and MeWo cell lines, although the response of these cells was different. Moreover, based on this study, there is no evidence for claiming a different magnitude of cytotoxicity between these two extracts.

Skin cancer, including related pathways and therapy and the role of luteolin derivatives as potential therapeutics

Cutaneous malignant melanoma is the fastest growing and the most aggressive form of skin cancer that is diagnosed. However, its incidence is relatively scarce compared to the highest mortality rate of all skin cancers. The much more common skin cancers include nonmelanoma malignant skin cancers. Moreover, over the past several decades, the frequency of all skin cancers has increased much more dynamically than that of almost any other type of cancer. Among the available therapeutic options for skin cancers, chemotherapy used immediately after the surgical intervention has been an essential element. Unfortunately, the main problem with conventional chemopreventive regimens involves the lack of response to treatment and the associated side effects. Hence, there is a need for much more effective anticancer drugs. Correspondingly, the targeted alternatives have involved phytochemicals, which are safer chemotherapeutic agents and exhibit competitive anticancer activity with high therapeutic efficacy. Among polyphenolic compounds, some flavonoids and their derivatives, which are mostly found in medicinal plants, have been demonstrated to influence the modulation of signaling pathways at each stage of the carcinogenesis process, which is also important in the context of skin cancers. Hence, this review focuses on an exhaustive overview of the therapeutic effects of luteolin and its derivatives in the treatment and prevention of skin cancers. The bioavailability and structure–activity relationships of luteolin derivatives are also discussed. This review is the first such complete account of all of the scientific reports concerning this particular group of natural compounds that target a specific area of neoplastic diseases.

Chemical Composition and Protective Effect of Young Barley (Hordeum vulgare L.) Dietary Supplements Extracts on UV-Treated Human Skin Fibroblasts in In Vitro Studies

Young barley seems to be a promising material for use as nutricosmetic due to the presence of many biologically active compounds. The aim of this study was to evaluate the effect of Hordeum vulgare L. extracts on human skin fibroblasts exposed to ultraviolet radiation B (UVB) radiation. Analysis of the chemical composition showed a predominance of 9,12,15-octadecatrienoic acid. The quality assessment showed that young barley preparations have high total polyphenolic content (TPC) and favourable total antioxidant status (TAS). They also contain antioxidant elements such as zinc, copper, and selenium. Furthermore, the analyzed products were found to be safe in terms of toxic elements (lead, cadmium and mercury) and lack of cytotoxic effect of young barley extracts on cells. In vitro bioactivity assays showed that young barley extract increased the survival rate and accelerated the migration of fibroblasts in research models with UVB radiation. The application of both extracts caused an increase in DNA biosynthesis, and in the number of cells arrested in S phase. Moreover, an inhibitory effect of the tested extracts on the expression of matrix metalloproteinase 2 (MMP-2) and matrix metalloproteinase 9 (MMP-9) was observed. The results indicate that young barley extracts, due to protective as well as restorative effect, could potentially be used in the production of nutricosmetics and skin care products.

DNA methylation: from model plants to vegetable crops

As a subgroup of horticultural crops, vegetable food is a kind of indispensable energy source for human beings, providing necessary nutritional components including vitamins, carbohydrates, dietary fiber, and active substances such as carotenoids and flavonoids. The developmental process of vegetable crops is not only regulated by environmental stimulations, but also manipulated by both genetic and epigenetic modifications. Epigenetic modifications are composed by several regulatory mechanisms, including DNA methylation, histone modification, chromatin remodeling, and non-coding RNAs. Among these modifications, DNA methylation functions in multiple biological pathways ranging from fundamental development to environmental stimulations by mediating transcriptomic alterations, resulting in the activation or silencing of target genes. In recent years, intensive studies have revealed that DNA methylation is essential to fruit development and ripening, indicating that the epigenome of fruit crops could be dynamically modified according to the specific requirements in the commercial production. Firstly, this review will present the mechanisms of DNA methylation, and update the understanding on active DNA demethylation in Arabidopsis thaliana. Secondly, this review will summarize the recent progress on the function of DNA methylation in regulating fruit ripening. Moreover, the possible functions of DNA methylation on controlling the expansion of edible organs, senescence of leafy vegetables, and anthocyanin pigmentation in several important vegetable crops will be discussed. Finally, this review will highlight the intractable issues that need to be resolved in the application of epigenome in vegetable crops, and provide perspectives for the potential challenges in the further studies.

Recent Molecular Mechanisms and Beneficial Effects of Phytochemicals and Plant-Based Whole Foods in Reducing LDL-C and Preventing Cardiovascular Disease

Abnormal lipid metabolism leads to the development of hyperlipidemia, a common cause of multiple chronic disorders, including cardiovascular disease (CVD), obesity, diabetes, and cerebrovascular disease. Low-density lipoprotein cholesterol (LDL-C) currently remains the primary target for treatment of hyperlipidemia. Despite the advancement of treatment and prevention of hyperlipidemia, medications used to manage hyperlipidemia are limited to allopathic drugs, which present certain limitations and adverse effects. Increasing evidence indicates that utilization of phytochemicals and plant-based whole foods is an alternative and promising strategy to prevent hyperlipidemia and CVD. The current review focuses on phytochemicals and their pharmacological mode of actions for the regulation of LDL-C and prevention of CVD. The important molecular mechanisms illustrated in detail in this review include elevation of reverse cholesterol transport, inhibition of intestinal cholesterol absorption, acceleration of cholesterol excretion in the liver, and reduction of cholesterol synthesis. Moreover, the beneficial effects of plant-based whole foods, such as fresh fruits, vegetables, dried nuts, flax seeds, whole grains, peas, beans, vegan diets, and dietary fibers in LDL-C reduction and cardiovascular health are summarized. This review concludes that phytochemicals and plant-based whole foods can reduce LDL-C levels and lower the risk for CVD.

An Evaluation of the Anti-Carcinogenic Response of Major Isothiocyanates in Non-Metastatic and Metastatic Melanoma Cells

Malignant melanoma is one of the most deadly types of solid cancers, a property mainly attributed to its highly aggressive metastatic form. On the other hand, different classes of isothiocyanates, a class of phytochemicals, present in cruciferous vegetables have been characterized by considerable anti-cancer activity in both in vitro and in vivo experimental models. In the current study, we investigated the anti-cancer response of five isothiocyanates in an in vitro model of melanoma consisting of non-metastatic (A375, B16F-10) and metastatic (VMM1, Hs294T) malignant melanoma as well as non-melanoma epidermoid carcinoma (A431) and non-tumorigenic melanocyte-neighboring keratinocyte (HaCaT) cells. Our aim was to compare different endpoints of cytotoxicity (e.g., reactive oxygen species, intracellular glutathione content, cell cycle growth arrest, apoptosis and necrosis) descriptive of an anti-cancer response between non-metastatic and metastatic melanoma as well as non-melanoma epidermoid carcinoma and non-tumorigenic cells. Our results showed that exposure to isothiocyanates induced an increase in intracellular reactive oxygen species and glutathione contents between non-metastatic and metastatic melanoma cells. The distribution of cell cycle phases followed a similar pattern in a manner where non-metastatic and metastatic melanoma cells appeared to be growth arrested at the G2/M phase while elevated levels of metastatic melanoma cells were shown to be at sub G1 phase, an indicator of necrotic cell death. Finally, metastatic melanoma cells were more sensitive apoptosis and/or necrosis as higher levels were observed compared to non-melanoma epidermoid carcinoma and non-tumorigenic cells. In general, non-melanoma epidermoid carcinoma and non-tumorigenic cells were more resistant under any experimental exposure condition. Overall, our study provides further evidence for the potential development of isothiocyanates as promising anti-cancer agents against non-metastatic and metastatic melanoma cells, a property specific for these cells and not shared by non-melanoma epidermoid carcinoma or non-tumorigenic melanocyte cells.