piperine and sulforaphane

Despite the significant advances in screening methods for early diagnosis, breast cancer remains a global threat and continues to be the leading cancer diagnosed in women, requiring effective therapy. Currently, combination therapy has become the hallmark of breast cancer treatment due to the high incidence of tumor recurrence and disease progression after monotherapeutic treatments, including surgery, radiotherapy, endocrine therapy, and chemotherapy. Over the past decades, there has been considerable interest in studying the anticancer effect of bioactive phytochemicals from medicinal plants combined with these conventional therapies. The rationale for this type of therapy is to use combinations of drugs that work by different mechanisms, thereby decreasing the likelihood that cancer cells will develop resistance, and also reduce the therapeutic dose and toxicity of single treatments. Three agents have received great attention with regard to their anticancer properties: 1) piperine, a dietary phytochemical isolated from black pepper (Piper nigrum L.) and long pepper (Piper longum L.); 2) sulforaphane, an isothiocyanate mainly derived from cruciferous vegetables; and 3) thymoquinone, the active compound from black seed (Nigella sativa L.). This review focused on the combined effect of these 3 compounds on conventional cancer therapy with the objective of observing enhanced efficacy compared with single treatments. This review also highlights the importance of the nanoformulation of such bioactive phytochemicals that could enhance their bioavailability by providing an efficient targeted delivery system with a reduced systemic dose while resulting in a more efficient dosing at the target site.

Topics: Alkaloids; Antineoplastic Agents; Benzodioxoles; Benzoquinones; Breast Neoplasms; Cell Line, Tumor; Chemotherapy, Adjuvant; Combined Modality Therapy; Female; Humans; In Vitro Techniques; Isothiocyanates; Patient Selection; Phytochemicals; Phytotherapy; Piperidines; Polyunsaturated Alkamides; Radiotherapy, Adjuvant; Sensitivity and Specificity; Sulfoxides

Cancer stem cells often have phenotypic and functional characteristics similar to normal stem cells including the properties of self-renewal and differentiation. Recent findings suggest that uncontrolled self-renewal may explain cancer relapses and may represent a critical target for cancer prevention. It is conceivable that the loss of regulatory molecules resulting from inappropriate consumption of specific foods and their constituents may foster the aberrant self-renewal of cancer stem cells. In fact, increasing evidence points to the network delivering signals for self-renewal from extracellular compartments to the nucleus including changes in stem cell environments, inducible expression of microRNAs, hyperplastic nuclear chromatin structures, and the on/off of differentiation process as possible sites of action for bioactive food components. Diverse dietary constituents such as vitamins A and D, genistein, (-)-epigallocatechin-3-gallate (EGCG), sulforaphane, curcumin, piperine, theanine and choline have been shown to modify self-renewal properties of cancer stem cells. The ability of these bioactive food components to influence the balance between proliferative and quiescent cells by regulating critical feedback molecules in the network including dickkopf 1 (DKK-1), secreted frizzled-related protein 2 (sFRP2), B cell-specific Moloney murine leukemia virus integration site 1 (Bmi-1) and cyclin-dependent kinase 6 (CDK6) may account for their biological response. Overall, the response to food components does not appear to be tissue or organ specific, suggesting there may be common cellular mechanisms. Unquestionably, additional studies are needed to clarify the physiological role of these dietary components in preventing the resistance of tumor cells to traditional drugs and cancer recurrence.

Topics: Alkaloids; Benzodioxoles; Catechin; Cell Differentiation; Cell Proliferation; Choline; Curcumin; Cyclin-Dependent Kinase 6; Diet; Epigenesis, Genetic; Gene Expression Regulation; Genistein; Glutamates; Humans; Intercellular Signaling Peptides and Proteins; Isothiocyanates; Membrane Proteins; Mesenchymal Stem Cells; Neoplastic Stem Cells; Nuclear Proteins; Piperidines; Plant Extracts; Polycomb Repressive Complex 1; Polyunsaturated Alkamides; Proto-Oncogene Proteins; Repressor Proteins; STAT1 Transcription Factor; Sulfoxides; Thiocyanates; Vitamin A; Vitamin D; Wnt Proteins

The emergence of cancer stem cell theory has profound implications for cancer chemoprevention and therapy. Cancer stem cells give rise to the tumor bulk through continuous self-renewal and differentiation. Understanding the mechanisms that regulate self-renewal is of greatest importance for discovery of anticancer drugs targeting cancer stem cells. Naturally occurring dietary compounds have received increasing attention in cancer chemoprevention. The anticancer effects of many dietary components have been reported for both in vitro and in vivo studies. Recently, a number of studies have found that several dietary compounds can directly or indirectly affect cancer stem cell self-renewal pathways. Herein we review the current knowledge of most common natural dietary compounds for their impact on self-renewal pathways and potential effect against cancer stem cells. Three pathways (Wnt/β-catenin, Hedgehog and Notch) are summarized for their functions in self-renewal of cancer stem cells. The dietary compounds, including curcumin, sulforaphane, soy isoflavone, epigallocatechin-3-gallate, resveratrol, lycopene, piperine and vitamin D(3), are discussed for their direct or indirect effect on these self-renewal pathways. Curcumin and piperine have been demonstrated to target breast cancer stem cells. Sulforaphane has been reported to inhibit pancreatic tumor-initiating cells and breast cancer stem cells. These studies provide a basis for preclinical and clinical evaluation of dietary compounds for chemoprevention of cancer stem cells. This may enable us to discover more preventive strategies for cancer management by reducing cancer resistance and recurrence and improving patient survival.

Topics: Alkaloids; Animals; Anticarcinogenic Agents; Benzodioxoles; beta Catenin; Carotenoids; Catechin; Cell Differentiation; Cell Proliferation; Cholecalciferol; Curcumin; Diet; Humans; Isoflavones; Isothiocyanates; Lycopene; Neoplasms; Neoplastic Stem Cells; Piperidines; Polyunsaturated Alkamides; Resveratrol; Signal Transduction; Stilbenes; Sulfoxides; Thiocyanates; Wnt Proteins