Curcumin, a polyphenolic compound derived from dietary spice turmeric, possesses diverse pharmacologic effects including anti-inflammatory, antioxidant, antiproliferative and antiangiogenic activities. Phase I clinical trials have shown that curcumin is safe even at high doses (12 g/day) in humans but exhibit poor bioavailability. Major reasons contributing to the low plasma and tissue levels of curcumin appear to be due to poor absorption, rapid metabolism, and rapid systemic elimination. To improve the bioavailability of curcumin, numerous approaches have been undertaken. These approaches involve, first, the use of adjuvant like piperine that interferes with glucuronidation; second, the use of liposomal curcumin; third, curcumin nanoparticles; fourth, the use of curcumin phospholipid complex; and fifth, the use of structural analogues of curcumin (e.g., EF-24). The latter has been reported to have a rapid absorption with a peak plasma half-life. Despite the lower bioavailability, therapeutic efficacy of...

Bioavailability of curcumin: problems and promises.

Curcumin as “Curecumin”: From kitchen to clinic

Curcumin is the active ingredient in the traditional herbal remedy and dietary spice turmeric (Curcuma longa). Curcumin has a surprisingly wide range of beneficial properties, including anti-inflammatory, antioxidant, chemopreventive and chemotherapeutic activity. The pleiotropic activities of curcumin derive from its complex chemistry as well as its ability to influence multiple signaling pathways, including survival pathways such as those regulated by NF-κB, Akt, and growth factors; cytoprotective pathways dependent on Nrf2; and metastatic and angiogenic pathways. Curcumin is a free radical scavenger and hydrogen donor, and exhibits both pro- and antioxidant activity. It also binds metals, particularly iron and copper, and can function as an iron chelator. Curcumin is remarkably non-toxic and exhibits limited bioavailability. Curcumin exhibits great promise as a therapeutic agent, and is currently in human clinical trials for a variety of conditions, including multiple myeloma, pancreatic cancer, myelodysplastic syndromes, colon cancer, psoriasis and Alzheimer’s disease.

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Curcumin: From ancient medicine to current clinical trials

Fourteen years have passed since nuclear factor-κB (NF-κB) was first shown to serve as a molecular lynchpin that links persistent infections and chronic inflammation to increased cancer risk. The young field of inflammation and cancer has now come of age, and inflammation has been recognized by the broad cancer research community as a hallmark and cause of cancer. Here, we discuss how the initial discovery of a role for NF-κB in linking inflammation and cancer led to an improved understanding of tumour-elicited inflammation and its effects on anticancer immunity.

NF-κB, inflammation, immunity and cancer: coming of age

Potential Therapeutic Effects of Curcumin, the Anti-inflammatory Agent, Against Neurodegenerative, Cardiovascular, Pulmonary, Metabolic, Autoimmune and Neoplastic Diseases

BACKGROUND
Because a role for nuclear factor-κB (NF-κB) has been implicated in the pathogenesis of pancreatic carcinoma, this transcription factor is a potential target for the treatment of this devastating disease. Curcumin (diferuloylmethane) is a phytochemical with potent NF-κB-inhibitory activity. It is pharmacologically safe, but its bioavailability is poor after oral administration.

METHODS
The authors encapsulated curcumin in a liposomal delivery system that would allow intravenous administration. They studied the in vitro and in vivo effects of this compound on proliferation, apoptosis, signaling, and angiogenesis using human pancreatic carcinoma cells. NF-κB was constitutively active in all human pancreatic carcinoma cell lines evaluated and liposomal curcumin consistently suppressed NF-κB binding (electrophoretic mobility gel shift assay) and decreased the expression of NF-κB-regulated gene products, including cyclooxygenase-2 (immunoblots) and interleukin-8 (enzyme-linked immunoassay), both of which have been implicated in tumor growth/invasiveness. These in vitro changes were associated with concentration and time-dependent antiproliferative activity (3-[4,5-dimethylthiazol-2-yl]2,5-diphenyltetrazolium bromide assay [MTT assay]) and proapoptotic effects (annexin V/propidium iodide staining [fluorescence-activated cell sorting] and polyadenosine-5′-diphosphate-ribose-polymerase cleavage).

RESULTS
The activity of liposomal curcumin was equal to or better than that of free curcumin at equimolar concentrations. In vivo, curcumin suppressed pancreatic carcinoma growth in murine xenograft models and inhibited tumor angiogenesis.

CONCLUSIONS
Liposomal curcumin down-regulated the NF-κB machinery, suppressed growth, and induced apoptosis of human pancreatic cells in vitro. Antitumor and antiangiogenesis effects were observed in vivo. The experiments in the current study provide a biologic rationale for treatment of patients suffering from pancreatic carcinoma with this nontoxic phytochemical encapsulated in liposomes for systemic delivery. Cancer 2005. © 2005 American Cancer Society.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/cncr.21300

Liposome-encapsulated curcumin: in vitro and in vivo effects on proliferation, apoptosis, signaling, and angiogenesis.

BACKGROUND

Pancreatic carcinoma is a lethal malignancy, with the best available therapeutic option—gemcitabine—yielding response rates of < 10%. Because nuclear factor-κB (NF-κB) has been determined to play a role in cell survival/proliferation in human pancreatic carcinoma, this transcription factor is a potential therapeutic target.



METHODS

The authors investigated the ability of curcumin (diferuloylmethane), an agent that is pharmacologically safe in humans, to modulate NF-κB activity.



RESULTS

NF-κB and IκB kinase (IKK) were constitutively active in all human pancreatic carcinoma cell lines examined, and curcumin consistently suppressed NF-κB binding (as assessed using an electrophoretic mobility gel-shift assay) and IKK activity. Curcumin decreased the expression of NF-κB–regulated gene products, including cyclooxygenase-2 (as assessed using immunoblot analysis), prostaglandin E2, and interleukin-8 (as assessed using an enzyme-linked immunoassay), all of which have been implicated in the growth and invasiveness of pancreatic carcinoma. These changes were associated with concentration- and time-dependent antiproliferative activity (as assessed using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide [MTT] assay) and proapoptotic effects (as assessed via annexin V/propidium iodide staining [fluorescence-activated cell sorting, as well as with the induction of polyadenosine-5′-diphosphate-ribose polymerase cleavage).



CONCLUSIONS

Curcumin down-regulated NF-κB and growth control molecules induced by NF-κB in human pancreatic cells. These effects were accompanied by marked growth inhibition and apoptosis. Through these findings, the authors provided a biologic rationale for the treatment of patients with pancreatic carcinoma using this nontoxic phytochemical. Cancer 2004. © 2004 American Cancer Society.

https://acsjournals.onlinelibrary.wiley.com/doi/pdf/10.1002/cncr.20605

Nuclear factor-kappaB and IkappaB kinase are constitutively active in human pancreatic cells, and their down-regulation by curcumin (diferuloylmethane) is associated with the suppression of proliferation and the induction of apoptosis.

BACKGROUND

Cytokines have been implicated in diverse processes that are relevant to pancreatic carcinoma, including cachexia, asthenia, and tumor growth. The objective of this study was to examine the association between serum levels of proinflammatory and antiinflammatory or angiogenic cytokines and the outcomes of patients with pancreatic carcinoma.



METHODS

Serum cytokine levels were measured by enzyme-linked immunosorbent assay from 51 patients with pancreatic carcinoma and from 48–62 healthy volunteers. Cytokine levels were compared with disease manifestations and overall survival.



RESULTS

Circulating levels of vascular endothelial growth factor, tumor necrosis factor alpha, interleukin-1α (IL-1α), and IL-1β were not elevated significantly in patients with pancreatic carcinoma, but levels of IL-6, IL-8, IL-10, and IL-1 receptor antagonist (IL-1RA) were elevated significantly (P 5.2 pg/mL or IL-10 levels > 9.8 pg/mL had significantly worse survival compared with patients who had lower IL-6 or IL-10 levels (P < 0.05). IL-8 levels were not associated with survival differences. Patients who had IL-1RA levels < 159 pg/mL had significantly worse survival compared with patients who had higher IL-1RA levels (P < 0.05). Higher IL-6, IL-10, and IL-8 levels were associated with poor performance status and/or weight loss. In multivariate analysis, only T4 tumors and high IL-6 levels were selected as independent prognostic factors for poor survival.



CONCLUSIONS

Circulating levels of several cytokines were high in patients with pancreatic carcinoma, and their association with weight loss and poor performance status suggested that they may be involved in these disease manifestations. Furthermore, serum cytokine levels, in particular IL-6, may be a useful prognostic marker. Cancer 2004. © 2004 American Cancer Society.

Cytokines in pancreatic carcinoma: correlation with phenotypic characteristics and prognosis.

Fatigue is prominent in cancer patients and probably multifactorial in origin. Factors contributing to fatigue include anemia, weight loss, fever, pain, medication, and infection. In cancer patients, many of these factors are influenced by a frequently disrupted balance between endogenous cytokine levels and their natural antagonists. Indeed, cancer cells and the immune system appear to overexpress a range of cytokines in patients with malignancies. Some of these cytokines act as autocrine or paracrine growth factors for the neoplastic tissue while simultaneously causing secondary symptoms related to fatigue. For instance, cancer-associated anemia may be due to a blunted erythropoietin response and/or cytokines (interleukin-1 [IL-1], IL-6, tumor necrosis factor-alpha [TNF-alpha]), which suppress erythropoiesis. Cancerous cachexia, a wasting syndrome and a hallmark of cancer, can be attributed to loss of appetite or enhanced energy expenditure. Several different interleukins, as well as TNF, interferon-gamma, and leukemia inhibitory factor, act as cachectins in animal models. Similarly, fever and night sweats are influenced by pyrogenic cytokines. Recently, molecules that function as cytokine antagonists have been identified. These molecules may be exploitable in combating the components of cancer-related fatigue, and may inhibit tumor growth as well.

The role of cytokines in cancer‐related fatigue

BACKGROUND
Nuclear factor-κB (NF-κB) plays a central role in cell survival and proliferation in human melanoma; therefore, the authors explored the possibility of exploiting NF-κB for melanoma treatment by using curcumin, an agent with known, potent, NF-κB-inhibitory activity and little toxicity in humans.

METHODS
Three melanoma cell lines (C32, G-361, and WM 266-4), all of which had B-raf mutations, were treated with curcumin, and the authors assessed its effects on viability ((3-[4,5-dimethylthiazol-2-yl]2,5-diphenyltetrazolium bromide assay) and apoptosis (flow-cytometric analysis of annexin V/propidium iodide-stained cells). Curcumin-treated cells also were examined for NF-κB binding activity (electrophoretic mobility shift assay) and for the activity of its upstream regulator, IκB kinase (IKK) (immune complex kinase assay). In addition, relevant signaling, as reflected by B-Raf kinase activity (kinase cascade assay), and steady-state levels of activated, downstream effectors, as reflected by mitogen-activated signal-regulated protein kinase (MEK), extracellular signal-regulated protein kinase (ERK), and Akt phosphorylation levels (immunoblots), were assessed.

RESULTS
Curcumin treatment decreased cell viability of all 3 cell lines in a dose-dependent manner (50% inhibitory concentration = 6.1–7.7 μM) and induced apoptosis. NF-κB and IKK were active constitutively in all melanoma cell lines examined, and curcumin, under apoptosis-inducing conditions, down-regulated NF-κB and IKK activities. However, curcumin did not inhibit the activities of B-Raf, MEK, or ERK, and Akt phosphorylation was enhanced. Furthermore, in the presence of curcumin, the Akt inhibitor 1L-6-hydroxymethyl-chiro-inositol 2-[(R)-2-O-methyl-3-O-octadecylcarbonate] no longer suppressed Akt phosphorylation.

CONCLUSIONS
Curcumin has potent antiproliferative and proapoptotic effects in melanoma cells. These effects were associated with the suppression of NF-κB and IKK activities but were independent of the B-Raf/MEK/ERK and Akt pathways. Cancer 2005. © 2005 American Cancer Society.

/pdf/curcumin-induced-antiproliferative-and-proapoptotic-effects-29k9ppm51y.pdf

Curcumin-induced antiproliferative and proapoptotic effects in melanoma cells are associated with suppression of IkappaB kinase and nuclear factor kappaB activity and are independent of the B-Raf/mitogen-activated/extracellular signal-regulated protein kinase pathway and the Akt pathway.

Razelle Kurzrock

Papers

Liposome-encapsulated curcumin: in vitro and in vivo effects on proliferation, apoptosis, signaling, and angiogenesis.

Nuclear factor-kappaB and IkappaB kinase are constitutively active in human pancreatic cells, and their down-regulation by curcumin (diferuloylmethane) is associated with the suppression of proliferation and the induction of apoptosis.

Cytokines in pancreatic carcinoma: correlation with phenotypic characteristics and prognosis.

The role of cytokines in cancer‐related fatigue

Curcumin-induced antiproliferative and proapoptotic effects in melanoma cells are associated with suppression of IkappaB kinase and nuclear factor kappaB activity and are independent of the B-Raf/mitogen-activated/extracellular signal-regulated protein kinase pathway and the Akt pathway.