Complementary and alternative therapies in skin cancer a literature review of biologically active compounds

Complementary and alternative medicine or therapies (CAM) are frequently used by skin cancers patients. Patient's self-administration of CAM in melanoma can reach up to 40%-50%. CAMs such as botanical agents, phytochemicals, herbal formulas ("black salve") and cannabinoids, among others, have been described in skin cancer patients. The objective of this review article was to acknowledge the different CAM for skin cancers through the current evidence, focusing on biologically active CAM rather than mind-body approaches. We searched MEDLINE database for articles published through July 2022, regardless of study design. Of all CAMs, phytochemicals have the best in vitro evidence-supporting efficacy against skin cancer including melanoma; however, to date, none have proved efficacy on human patients. Of the phytochemicals, Curcumin is the most widely studied. Several findings support Curcumin efficacy in vitro through various molecular pathways, although most studies are in the preliminary phase. In addition, the use of alternative therapies is not exempt of risks physicians should be aware of their adverse effects, interactions with standard treatments, and possible complications arising from CAM usage. There is emerging evidence for CAM use in skin cancer, but no human clinical trials support the effectiveness of any CAM in the treatment of skin cancer to date. Nevertheless, patients worldwide frequently use CAM, and physicians should educate themselves on currently available CAMs.

Drug Delivery Systems and Flavonoids: Current Knowledge in Melanoma Treatment and Future Perspectives

Melanoma is an aggressive form of skin cancer with a high prevalence in the population. An early diagnosis is crucial to cure this disease. Still, when this is not possible, combining potent pharmacological agents and effective drug delivery systems is essential to achieve optimal treatment and improve patients' quality of life. Nanotechnology application in biomedical sciences to encapsulate anticancer drugs, including flavonoids, in order to enhance therapeutic efficacy has attracted particular interest. Flavonoids have shown effectiveness against various types of cancers including in melanoma, but they show low aqueous solubility, low stability and very poor oral bioavailability. The utilization of novel drug delivery systems could increase flavonoid bioavailability, thereby potentiating its antitumor effects in melanoma. This review summarizes the potential of different flavonoids in melanoma treatment and the several nanosystems used to improve their biological activity, considering published information that reported improved biological and pharmacological properties of encapsulated flavonoids.

Genistein, a Potential Phytochemical against Breast Cancer Treatment-Insight into the Molecular Mechanisms

Breast cancer (BC) is one of the most common malignancies in women. Although widespread successful synthetic drugs are available, natural compounds can also be considered as significant anticancer agents for treating BC. Some natural compounds have similar effects as synthetic drugs with fewer side effects on normal cells. Therefore, we aimed to unravel and analyze several molecular mechanisms of genistein (GNT) against BC. GNT is a type of dietary phytoestrogen included in the flavonoid group with a similar structure to estrogen that might provide a strong alternative and complementary medicine to existing chemotherapeutic drugs. Previous research reported that GNT could target the estrogen receptor (ER) human epidermal growth factor receptor-2 (HER2) and several signaling molecules against multiple BC cell lines and sensitize cancer cell lines to this compound when used at an optimal inhibitory concentration. More specifically, GNT mediates the anticancer mechanism through apoptosis induction, arresting the cell cycle, inhibiting angiogenesis and metastasis, mammosphere formation, and targeting and suppressing tumor growth factors. Furthermore, it acts via upregulating tumor suppressor genes and downregulating oncogenes in vitro and animal model studies. In addition, this phytochemical synergistically reverses the resistance mechanism of standard chemotherapeutic drugs, increasing their efficacy against BC. Overall, in this review, we discuss several molecular interactions of GNT with numerous cellular targets in the BC model and show its anticancer activities alone and synergistically. We conclude that GNT can have favorable therapeutic advantages when standard drugs are not available in the pharma markets.

Genistein: An Integrative Overview of Its Mode of Action, Pharmacological Properties, and Health Benefits

Genistein is an isoflavone first isolated from the brooming plant Dyer's Genista tinctoria L. and is widely distributed in the Fabaceae family. As an isoflavone, mammalian genistein exerts estrogen-like functions. Several biological effects of genistein have been reported in preclinical studies, such as the antioxidant, anti-inflammatory, antibacterial, and antiviral activities, the effects of angiogenesis and estrogen, and the pharmacological activities on diabetes and lipid metabolism. The purpose of this review is to provide up-to-date evidence of preclinical pharmacological activities with mechanisms of action, bioavailability, and clinical evidence of genistein. The literature was researched using the most important keyword "genistein" from the PubMed, Science, and Google Scholar databases, and the taxonomy was validated using The Plant List. Data were also collected from specialized books and other online resources. The main positive effects of genistein refer to the protection against cardiovascular diseases and to the decrease of the incidence of some types of cancer, especially breast cancer. Although the mechanism of protection against cancer involves several aspects of genistein metabolism, the researchers attribute this effect to the similarity between the structure of soy genistein and that of estrogen. This structural similarity allows genistein to displace estrogen from cellular receptors, thus blocking their hormonal activity. The pharmacological activities resulting from the experimental studies of this review support the traditional uses of genistein, but in the future, further investigations are needed on the efficacy, safety, and use of nanotechnologies to increase bioavailability and therapeutic efficacy.

Natural isoflavonoids in invasive cancer therapy: From bench to bedside

Cancer is a public health problem worldwide, and one of the crucial steps within tumor progression is the invasion and metastasis of cancer cells, which are directly related to cancer-associated deaths in patients. Recognizing the molecular markers involved in invasion and metastasis is essential to find targeted therapies in cancer. Interestingly, about 50% of the discovered drugs used in chemotherapy have been obtained from natural sources such as plants, including isoflavonoids. Until now, most drugs are used in chemotherapy targeting proliferation and apoptosis-related molecules. Here, we review recent studies about the effect of isoflavonoids on molecular targets and signaling pathways related to invasion and metastasis in cancer cell cultures, in vivo assays, and clinical trials. This review also reports that glycitein, daidzein, and genistein are the isoflavonoids most studied in preclinical and clinical trials and displayed the most anticancer activity targeting invasion-related proteins such as MMP-2 and MMP-9 and also EMT-associated proteins. Therefore, the diversity of isoflavonoids is promising molecules to be used as chemotherapeutic in invasive cancer. In the future, more clinical trials are needed to validate the effectiveness of the various natural isoflavonoids in the treatment of invasive cancer.

Medicinal Plants Towards Modeling Skin Cancer

Skin cancer remains a major cause of mortality worldwide. It can be divided into melanoma and non-melanoma cancer, which comprise mainly squamous cell carcinoma and basal cell carcinoma. Although conventional therapies have ameliorated the management of skin cancer, the search for chemopreventive compounds is still the most effective and safer strategy to treat cancer. Nowadays, chemoprevention is recognized as a novel approach to prevent or inhibit carcinogenesis steps with the use of natural products. Crude extracts of plants and isolated phytocompounds are considered chemopreventive agents since they harbor anti-inflammatory, antioxidant and anti-oncogenic properties against many types of diseases and cancers. In this review, we will discuss the therapeutic effect and preventive potential of selected medicinal plants used as crude extracts or as phytocompounds against melanoma and non-melanoma cutaneous cancers.

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

Human skin is continuously subjected to environmental stresses, as well as extrinsic and intrinsic noxious agents. Although skin adopts various molecular mechanisms to maintain homeostasis, excessive and repeated stresses can overwhelm these systems, leading to serious cutaneous damage, including both melanoma and non-melanoma skin cancers. Phytochemicals present in the diet possess the desirable effects of protecting the skin from damaging free radicals as well as other benefits. Dietary phytochemicals appear to be effective in preventing skin cancer and are inexpensive, widely available, and well tolerated. Multiple in vitro and in vivo studies have demonstrated the significant anti-inflammatory, antioxidant, and anti-angiogenic characteristics of dietary phytochemicals against skin malignancy. Moreover, dietary phytochemicals affect multiple important cellular processes including cell cycle, angiogenesis, and metastasis to control skin cancer progression. Herein, we discuss the advantages of key dietary phytochemicals in whole fruits and vegetables, their bioavailability, and underlying molecular mechanisms for preventing skin cancer. Current challenges and future prospects for research are also reviewed. To date, most of the chemoprevention investigations have been conducted preclinically, and additional clinical trials are required to conform and validate the preclinical results in humans.