Today's treatments cannot cure GBM patients but only extend their overall survival. The use of chemoradiation, immunotherapy, and radio sensitizers as an adjuvant therapy cannot reduce the high rates of recurrence within a few months after treatment. Radiotherapy will remain the backbone of the treatment but new treatment modalities must be developed.
Curcumin, commonly called diferuloyl methane, is a hydrophobic polyphenol derived from rhizome (turmeric) of the herb Curcuma longa. Extensive research over the last half century has revealed important functions of curcumin. In vitro and in vivo research has shown various activities, such as anti-inflammatory, cytokines release, antioxidant, immunomodulatory, enhancing of the apoptotic process, and anti-angiogenic properties. Curcumin has also been shown to be a mediator of chemo-resistance and radio-resistance. The anti-cancer effect has been seen in a few clinical trials, mainly as a native chemoprevention agent in colon and pancreatic cancer, cervical neoplasia and Barrets metaplasia. Some clinical studies with healthy volunteers revealed a low bioavailability of curcumin, casting doubt on the use of curcumin only as food additive. Our clinical experience with curcumin, along with the anti-metabolite gemcitabine in the treatment of patients with advanced pancreatic carcinoma, produced an objective response in less than 10% of patients, with a minor effect on survival. However, the safety of this combination was proved. Curcumin's potent anti-proliferative activity interacting with several intracellular signal transduction pathways may potentiate the anti-tumor effect of gemcitabine. The preclinical data lead to various, but still scarce, clinical studies (some on-going) that demonstrated the possible efficacy of this treatment as a chemopreventive or chemotherapeutic agent. This review will focus on the clinical evidence, including our experience with curcumin as a chemopreventive and therapeutic agent and the in vitro background results.
Curcumin has a potent antiproliferative activity and can also potentiate the antitumor effect of gemcitabine. This study was undertaken to evaluate the activity and feasibility of gemcitabine in combination with curcumin in patients with advanced pancreatic cancer. Seventeen patients were enrolled in the study and received 8,000 mg of curcumin by mouth daily, concurrently with gemcitabine 1,000 mg/m(2) IV weekly × 3 of 4 wk; 5 patients (29%) discontinued curcumin after a few days to 2 wk due to intractable abdominal fullness or pain, and the dose of curcumin was reduced to 4,000 mg/day because of abdominal complaints in 2 other patients. One of 11 evaluable patients (9%) had partial response, 4 (36%) had stable disease, and 6 (55%) had tumor progression. Time to tumor progression was 1-12 mo (median 2½), and overall survival was 1-24 mo (median 5). Low compliance for curcumin at a dose of 8,000 mg/day, when taken together with systemic gemcitabine, may prevent the use of high doses of oral curcumin needed to achieve systemic effect. Further studies should be conducted to evaluate the ability of other formulations of curcumin to enhance the effect of chemotherapy in cancer patients.
One of the most exciting concepts being explored in cancer research today is the idea of cancer stem cells. Evidence for the existence of such cells was first proposed for haematological malignancies and, more recently, for solid tumors, including breast, brain, colon and pancreatic cancer. The cancer stem cell hypothesis states that a minority of transformed stem cells, or progenitors with acquired self-renewal properties, are the source of tumor cell renewal and thereby determine the behaviour of tumors, including proliferation, spreading and response to chemo- and radiotherapy. Indeed, just as somatic stem cells may be resistant to the induction of apoptosis by cytotoxic agents and radiation therapy, cancer stem cells may display increased resistance to these agents as compared with the more differentiated cells that comprise the mass of tumors. More specifically, the reactivation of varied developmental signalling cascades (epidermal growth factor (EGF)/EGFR, stem cell factor (SCF)/KIT, sonic hedgehog, Notch, and/or Wnt/beta-catenin) combined with the increased DNA repair mechanisms and ABC transporter-mediated drug efflux in cancer stem cells may be responsible for their resistance to conventional therapies. Furthermore, changes in the local microenvironment of cancer stem cells may also influence their behaviour. Thus, the molecular targeting of such highly tumorigenic cancer cells must be considered for improving the efficacy of the current anti-cancer strategies with the aim to sensitize tumors toward conventional therapies and effectively abrogate tumorigenesis. This review provides a summary of some developments in the field of cancer stem cell targeting and highlights aspects where it could be of help in the drug discovery process.
BackgroundThe purpose of this pilot study was to detect a correlation between serum cytokine levels and severity of mucositis, necessitating installation of a percutaneous endoscopic gastrostomy tube (PEG) in head and neck (H&N) cancer patients receiving combined chemo-radiation therapy.Patients and MethodsFifteen patients with H&N epithelial cancer were recruited to this study. All patients received radiotherapy to the H&N region, with doses ranging from 50-70 Gy. Chemotherapy with cisplatin, carboplatin, 5-fluorouracil and taxanes was given to high-risk patients, using standard chemotherapy protocols. Patients were evaluated for mucositis according to WHO common toxicity criteria, and blood samples were drawn for inflammatory (IL-1, IL-6, IL-8, TNF-α) and anti-inflammatory (IL-10) cytokine levels before and during treatment.ResultsA positive correlation was found between IL-6 serum levels and severity of mucositis and dysphagia; specifically, high IL-6 levels at week 2 were correlated with a need for PEG tube installation. A seemingly contradictory correlation was found between low IL-8 serum levels and a need for a PEG tube.ConclusionThese preliminary results, indicating a correlation between IL-6 and IL-8 serum levels and severity of mucositis and a need for a PEG tube installation, justify a large scale study.
Various in-vitro and in-vivo and scarce number of clinical studies on curcumin were identified. The various effects and properties of curcumin are summarized in this review, including preclinical and especially clinical studies. This review concentrates on recent knowledge and research with curcumin clinical applications, and clinical studies, focusing on studies published between 2008 and 2011 demonstrating the gap between preclinical and clinical research.
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