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In the field of molecular biology, the peroxisome proliferator-activated receptors (PPARs) are a group of nuclear receptor proteins that function as transcription factors regulating the expression of genes.[1] PPARs play essential roles in the regulation of cellular differentiation, development, and metabolism (carbohydrate, lipid, protein), and tumorigenesis[2] of higher organism.

Berberine, a natural product, induces G1-phase cell cycle arrest and caspase-3-dependent apoptosis in human prostate carcinoma cells. Mantena SK, Sharma SD, Katiyar SK. Mol Cancer Ther. 2006 Feb;5(2):296-308. PMID: 16505103 doi: 10.1158/1535-7163.MCT-05-0448 The effectiveness of berberine in checking the growth of androgen-insensitive, as well as androgen-sensitive, prostate cancer cells without affecting the growth of normal prostate epithelial cells indicates that it may be a promising candidate for prostate cancer therapy. The evaluation of ancient herbal medicines may indicate novel strategies for the treatment of prostate cancer, which remains the leading cause of cancer-related deaths in American men (1). In our present investigation, we show that a naturally occurring isoquinoline alkaloid, berberine, significantly inhibits the proliferation and reduces the viability of DU145 and PC-3 as well as LNCaP cells (Fig. 1), which suggests that berberine may be an effective chemotherapeutic agent against both androgen-sensitive and androgen-insensitive prostate cancer cells. Importantly, we found that berberine did not exhibit toxicity to nonneoplastic human prostate epithelial cells under the conditions used, except for a moderate reduction in cell viability at higher concentrations when cells were treated in vitro for an extended period of time. In conclusion, the results of the present study indicate that berberine inhibits proliferation and induces G1-phase arrest and apoptosis in human prostate cancer cells but not in normal human prostate epithelial cells. In addition, we provide mechanistic evidence that berberine-induced apoptosis in prostate carcinoma cells, particularly hormone-refractory prostate carcinoma cells, is mediated through enhanced expression of Bax, disruption of the mitochondrial membrane potential, and activation of caspase-3.

Conjugated linoleic acid promotes human adipocyte insulin resistance through NFkappaB-dependent cytokine production. Chung S, Brown JM, Provo JN, Hopkins R, McIntosh MK. J Biol Chem. 2005 Nov 18;280(46):38445-56. Epub 2005 Sep 9. PMID: 16155293 doi: 10.1074/jbc.M508159200 Collectively, these data demonstrate for the first time that trans-10, cis-12 CLA promotes NFkappaB activation and subsequent induction of IL-6, which are at least in part responsible for trans-10, cis-12 CLA-mediated suppression of peroxisome proliferator-activated receptor gamma target gene expression and insulin sensitivity in mature human adipocytes. In summary, our in vitro data demonstrate that a physiological level of trans-10, cis-12 CLA activates NFκB- and ERK1/2-dependent cytokine production, which together suppress PPARγ and Glut4 levels and lead to impaired glucose uptake. Studies are currently under way examining 1) how CLA regulates PPARγ and the expression of its target genes, 2) the specific signaling role of SV cells and adipocytes in mediating the TG-lowering actions of CLA, and 3) the CLA-induced, upstream signal that activates NFκB and ERK1/2.

White button mushroom phytochemicals inhibit aromatase activity and breast cancer cell proliferation. Grube BJ, Eng ET, Kao YC, Kwon A, Chen S. J Nutr. 2001 Dec;131(12):3288-93. PMID: 11739882

Docosahexaenoic acid inhibits superoxide dismutase 1 gene transcription in human cancer cells: the involvement of peroxisome proliferator-activated receptor alpha and hypoxia-inducible factor-2alpha signaling. Tuller ER, Beavers CT, Lou JR, Ihnat MA, Benbrook DM, Ding WQ. Mol Pharmacol. 2009 Sep;76(3):588-95. Epub 2009 Jun 15. PMID: 19528198

"PPAR modulators are drugs which act upon the peroxisome proliferator-activated receptor."

Th1/Th2 balance: the hypothesis, its limitations, and implications for health and disease. Kidd P. Altern Med Rev. 2003 Aug;8(3):223-46. Review. PMID: 12946237 Th1 pathways typically produce activation of cytotoxic T lymphocytes (Tc), NK cells, macrophages, and monocytes, all of which can attack cancer cells and generally defend against tumors. 55 IFN-gamma and other Th1 cytokines are typically lower in advanced cancer patients, while the Th2 marker IL-4 can be higher or unchanged.56 Nodules of non-small cell lung cancer freshly removed from patients expressed a marked imbalance toward Th2, as did biopsy samples from basal cell carcinoma.57 In prostate cancer patients IL-2 was low (Th1) and IL-10 high.58 IL-10 is a confirmed Th1-suppressive cytokine, and heightened IL-10 is a common factor in cancer.55 IL-10 has a variety of suppressive effects that include inhibiting Th1 cytokine production, down-regulating APC and NK cell function, and lowering overall T-cell proliferation.57 Especially under the influence of IL-4 (Th2), tumor cells apparently up-regulate IL-10 that suppresses nearby killer cells. Tumor-derived IL-10 has been documented in lymphoma, ovarian carcinoma, melanoma, neuroblastoma, and renal cell and colon carcinoma.57 IL-12 is another cytokine that can be up-regulated by Th1 activity and inhibited by Th2.59 A low IL-12/IL-10 ratio was found in cervical cancer patients.55 Recent clinical studies suggest elevated IL-10 is predictive of a poor prognosis. 57 With both IL-4 and IL-10 being proven inhibitors of Th1 and promoters of Th2 activity, the recognized capability of cancerous tissue to suppress immunity is readily rationalized.

Anticancer properties of Ganoderma lucidum methanol extracts in vitro and in vivo. Harhaji Trajković LM, Mijatović SA, Maksimović-Ivanić DD, Stojanović ID, Momcilović MB, Tufegdzić SJ, Maksimović VM, Marjanović ZS, Stosić-Grujicić SD. Nutr Cancer. 2009;61(5):696-707. PMID: 19838944 DOI: 10.1080/01635580902898743 Anticancer activities of various extracts of the medicinal mushroom, Ganoderma lucidum, have been widely demonstrated and are mainly associated with the presence of different bioactive polysaccharides and triterpenoids. We have evaluated and compared in vitro and in vivo the antitumor effects of two preparations from Ganoderma lucidum: a methanol extract containing total terpenoids (GLme) and a purified methanol extract containing mainly acidic terpenoids (GLpme). Both extracts inhibited tumor growth of B16 mouse melanoma cells inoculated subcutaneously into syngeneic C57BL/6 mice and reduced viability of B16 cells in vitro, whereby GLme exhibited stronger effect. Furthermore, anticancer activity of GLme was demonstrated for the first time against two other rodent tumor cell lines, L929-mouse fibrosarcoma and C6-rat astrocytoma. The mechanism of antitumor activity of GLme comprised inhibition of cell proliferation and induction of caspase-dependent apoptotic cell death mediated by upregulated p53 and inhibited Bcl-2 expression. Moreover, the antitumor effect of the GLme was associated with intensified production of reactive oxygen species, whereas their neutralization by the antioxidant, N-acetyl cysteine, resulted in partial recovery of cell viability. Thus, our results suggest that GLme might be a good candidate for treatment of diverse forms of cancers.

Vitamin D and calcium insufficiency-related chronic diseases: molecular and cellular pathophysiology. Peterlik M, Cross HS. Eur J Clin Nutr. 2009 Dec;63(12):1377-86. Epub 2009 Sep 2. PMID: 19724293 doi:10.1038/ejcn.2009.105 A compromised vitamin D status, characterized by low 25-hydroxyvitamin D (25-(OH)D) serum levels, and a nutritional calcium deficit are widely encountered in European and North American countries, independent of age or gender. Both conditions are linked to the pathogenesis of many degenerative, malignant, inflammatory and metabolic diseases. Studies on tissue-specific expression and activity of vitamin D metabolizing enzymes, 25-(OH)D-1alpha-hydroxylase and 25-(OH)D-24-hydroxylase, and of the extracellular calcium-sensing receptor (CaR) have led to the understanding of how, in non-renal tissues and cellular systems, locally produced 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) and extracellular Ca2+ act jointly as key regulators of cellular proliferation, differentiation and function. Impairment of cooperative signalling from the 1,25-(OH)2D3-activated vitamin D receptor (VDR) and from the CaR in vitamin D and calcium insufficiency causes cellular dysfunction in many organs and biological systems, and, therefore, increases the risk of diseases, particularly of osteoporosis, colorectal and breast cancer, inflammatory bowel disease, insulin-dependent diabetes mellitus type I, metabolic syndrome, diabetes mellitus type II, hypertension and cardiovascular disease. Understanding the underlying molecular and cellular processes provides a rationale for advocating adequate intake of vitamin D and calcium in all populations, thereby preventing many chronic diseases worldwide.

Vitamin D: the alternative hypothesis. Albert PJ, Proal AD, Marshall TG. Autoimmun Rev. 2009 Jul;8(8):639-44. Epub 2009 Feb 12. Review. PMID: 19393200 Emerging molecular evidence suggests that symptomatic improvements among those administered vitamin D is the result of 25-D's ability to temper bacterial-induced inflammation by slowing VDR activity. While this results in short-term palliation, persistent pathogens that may influence disease progression, proliferate over the long-term.

Scientists have known that cruciferous vegetables contain a host of chemopreventive agents that act in many different ways to block cancer development.2 Key among these products are indole-3-carbinol (I3C) and sulforaphane.1,3 Cancer cells need a brisk blood supply to support their rampant growth and reproduction. Preliminary studies in vitro and in vivo have found that apigenin inhibits blood vessel growth (angiogenesis) in human ovarian cancer cells, blocking production of two main signaling molecules required to stimulate vessel growth.20,21 Scientists confirmed this effect in ovarian cancer cells, also finding that apigenin strongly inhibits cell proliferation.22 Apigenin and BITC: Complementary Cancer Protection Cancer cells also need energy to support their frenetic reproductive activity. Researchers applied apigenin to human pancreatic cancer cells in culture and studied the cells' uptake of glucose.14 Astonishingly, they found that apigenin deprived energy-hungry cancer cells of glucose to support their voracious appetites and aggressive growth. It did this by down-regulating vital glucose-transporting proteins in cancer cells. This approach could effectively starve deadly cancer cells and stop them in their tracks. Another cruciferous vegetable component receiving rave reviews is the sulfur-containing molecule benzyl isothiocyanate, or BITC (pronounced "bitsy"). As with apigenin, population studies have shown that higher intakes of BITC correlate with reduced risk of cancers of the lung, breast, and colon30 while blocking cancer development in a host of different ways. BITC induces breast cancer cell death by apoptosis (programmed cell death), interfering with cancer cells' energy utilization and causing them to die off before they can contribute to tumor growth.31,32 In human ovarian cancer cells, BITC induces apoptosis by a different mechanism. It stimulates "signaling" molecules that tell cancer cells it's time to close up shop.

n-3 fatty acids and gene expression. Deckelbaum RJ, Worgall TS, Seo T. Am J Clin Nutr. 2006 Jun;83(6 Suppl):1520S-1525S. Review. Erratum in: Am J Clin Nutr. 2006 Oct;84(4):949. PMID: 16841862 Accumulating evidence in both humans and animal models clearly indicates that a group of very-long-chain polyunsaturated fatty acids, the n-3 fatty acids (or omega-3), have distinct and important bioactive properties compared with other groups of fatty acids. n-3 Fatty acids are known to reduce many risk factors associated with several diseases, such as cardiovascular diseases, diabetes, and cancer. The mechanisms whereby n-3 fatty acids affect gene expression are complex and involve multiple processes. As examples, n-3 fatty acids regulate 2 groups of transcription factors, such as sterol-regulatory-element binding proteins and peroxisome proliferator-activated receptors, that are critical for modulating the expression of genes controlling both systemic and tissue-specific lipid homeostasis. Modulation of specific genes by n-3 fatty acids and cross-talk between these genes are responsible for many effects of n-3 fatty acids.

Apigenin inhibits growth and motility but increases gap junctional coupling intensity in rat prostate carcinoma (MAT-LyLu) cell populations. Czernik M, Sroka J, Madeja Z, Czyz J. Cell Mol Biol Lett. 2008;13(3):327-38. Epub 2008 Feb 21. PMID: 18292973 DOI: 10.2478/s11658-008-0003-z This in vitro data indicates that apigenin may affect cancer development in general, and prostate carcinogenesis in particular, via its influence on cellular activities decisive for both cancer promotion and progression, including cell proliferation, gap junctional coupling and cell motility and invasiveness.

Berberine inhibits growth, induces G1 arrest and apoptosis in human epidermoid carcinoma A431 cells by regulating Cdki-Cdk-cyclin cascade, disruption of mitochondrial membrane potential and cleavage of caspase 3 and PARP. Mantena SK, Sharma SD, Katiyar SK. Carcinogenesis. 2006 Oct;27(10):2018-27. Epub 2006 Apr 18. PMID: 16621886 doi:10.1093/carcin/bgl043 In the present investigation, we show that berberine, which is present abundantly in Berberis plant species, significantly inhibits the viability, proliferation and induces cell death in human epidermoid carcinoma A431 cells (Figure 1), but this effect was not found in normal human epidermal keratinocytes under the identical conditions, except for a non-significant reduction in cell viability at higher concentrations of berberine (50 and 75 µM) and treatment of cells for a longer period of time (72 h). These data suggested that berberine may be examined as an effective chemotherapeutic agent against non-melanoma skin cancers. In conclusion, our study indicates that berberine inhibits growth, induces G1 arrest and apoptotic cell death of human epidermoid carcinoma A431 cells. We also provide mechanistic evidences that berberine-induced apoptosis in human epidermoid carcinoma cells is mediated through disruption of mitochondrial membrane potential and activation of caspase 3 pathway, although other pathways may have a role and that require further investigation. Moreover, further in vivo studies are required to determine whether berberine could be an effective chemotherapeutic agent for the prevention of non-melanoma skin cancers.