Antiproliferative Effects of Fluoxetine on Colon Cancer Cells and in a Colonic Carcinogen Mouse Model

The antidepressant fluoxetine has been under discussion because of its potential influence on cancer risk. It was found to inhibit the development of carcinogen-induced preneoplastic lesions in colon tissue, but the mechanisms of action are not well understood. Therefore, we investigated anti-proliferative effects, and used HT29 colon tumor cells in vitro, as well as C57BL/6 mice exposed to intra-rectal treatment with the carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) as models. Fluoxetine increased the percentage of HT29 cells in the G(0)/G(1) phase of cell-cycle, and the expression of p27 protein. This was not related to an induction of apoptosis, reactive oxygen species or DNA damage. In vivo, fluoxetine reduced the development of MNNG-induced dysplasia and vascularization-related dysplasia in colon tissue, which was analyzed by histopathological techniques. An anti-proliferative potential of fluoxetine was observed in epithelial and stromal areas. It was accompanied by a reduction of VEGF expression and of the number of cells with angiogenic potential, such as CD133, CD34, and CD31-positive cell clusters. Taken together, our findings suggest that fluoxetine treatment targets steps of early colon carcinogenesis. This confirms its protective potential, explaining at least partially the lower colon cancer risk under antidepressant therapy.

Bevacizumab plus oxaliplatin-based chemotherapy as adjuvant treatment for colon cancer (AVANT): a phase 3 randomised controlled trial

Background: Bevacizumab improves the efficacy of oxaliplatin-based chemotherapy in metastatic colorectal cancer. Our aim was to assess the use of bevacizumab in combination with oxaliplatin-based chemotherapy in the adjuvant treatment of patients with resected stage III or high-risk stage II colon carcinoma. Methods: Patients from 330 centres in 34 countries were enrolled into this phase 3, open-label randomised trial. Patients with curatively resected stage III or high-risk stage II colon carcinoma were randomly assigned (1: 1: 1) to receive FOLFOX4 (oxaliplatin 85 mg/m(2), leucovorin 200 mg/m(2), and fluorouracil 400 mg/m(2) bolus plus 600 mg/m(2) 22-h continuous infusion on day 1; leucovorin 200 mg/m(2) plus fluorouracil 400 mg/m(2) bolus plus 600 mg/m(2) 22-h continuous infusion on day 2) every 2 weeks for 12 cycles; bevacizumab 5 mg/kg plus FOLFOX4 (every 2 weeks for 12 cycles) followed by bevacizumab monotherapy 7.5 mg/kg every 3 weeks (eight cycles over 24 weeks); or bevacizumab 7.5 mg/kg plus XELOX (oxaliplatin 130 mg/m(2) on day 1 every 2 weeks plus oral capecitabine 1000 mg/m(2) twice daily on days 1-15) every 3 weeks for eight cycles followed by bevacizumab monotherapy 7.5 mg/kg every 3 weeks (eight cycles over 24 weeks). Block randomisation was done with a central interactive computerised system, stratified by geographic region and disease stage. Surgery with curative intent occurred 4-8 weeks before randomisation. The primary endpoint was disease-free survival, analysed for all randomised patients with stage III disease. This study is registered with ClinicalTrials.gov, number NCT00112918. Findings: Of the total intention-to-treat population (n=3451), 2867 patients had stage III disease, of whom 955 were randomly assigned to receive FOLFOX4, 960 to receive bevacizumab-FOLFOX4, and 952 to receive bevacizumab-XELOX. After a median follow-up of 48 months (range 0-66 months), 237 patients (25%) in the FOLFOX4 group, 280 (29%) in the bevacizumab-FOLFOX4 group, and 253 (27%) in the bevacizumab-XELOX group had relapsed, developed a new colon cancer, or died. The disease-free survival hazard ratio for bevacizumab-FOLFOX4 versus FOLFOX4 was 1.17 (95% CI 0.98-1.39; p=0.07), and for bevacizumab-XELOX versus FOLFOX4 was 1.07 (0.90-1.28; p=0.44). After a minimum follow-up of 60 months, the overall survival hazard ratio for bevacizumab-FOLFOX4 versus FOLFOX4 was 1.27 (1.03-1.57; p=0.02), and for bevacizumab-XELOX versus FOLFOX4 was 1.15 (0.93-1.42; p=0.21). The 573 patients with high-risk stage II cancer were included in the safety analysis. The most common grade 3-5 adverse events were neutropenia (FOLFOX4: 477 [42%] of 1126 patients, bevacizumab-FOLFOX4: 416 [36%] of 1145 patients, and bevacizumab-XELOX: 74 [7%] of 1135 patients), diarrhoea (110 [10%], 135 [12%], and 181 [16%], respectively), and hypertension (12 [1%], 122 [11%], and 116 [10%], respectively). Serious adverse events were more common in the bevacizumab groups (bevacizumab-FOLFOX4: 297 [26%]; bevacizumab-XELOX: 284 [25%]) than in the FOLFOX4 group (226 [20%]). Treatment-related deaths were reported in one patient receiving FOLFOX4, two receiving bevacizumab-FOLFOX4, and five receiving bevacizumab-XELOX. Interpretation: Bevacizumab does not prolong disease-free survival when added to adjuvant chemotherapy in resected stage III colon cancer. Overall survival data suggest a potential detrimental effect with bevacizumab plus oxaliplatin-based adjuvant therapy in these patients. On the basis of these and other data, we do not recommend the use of bevacizumab in the adjuvant treatment of patients with curatively resected stage III colon cancer.

ESMO Consensus Guidelines for management of patients with colon and rectal cancer. A personalized approach to clinical decision making

Colorectal cancer (CRC) is the most common tumour type in both sexes combined in Western countries. Although screening programmes including the implementation of faecal occult blood test and colonoscopy might be able to reduce mortality by removing precursor lesions and by making diagnosis at an earlier stage, the burden of disease and mortality is still high. Improvement of diagnostic and treatment options increased staging accuracy, functional outcome for early stages as well as survival. Although high quality surgery is still the mainstay of curative treatment, the management of CRC must be a multi-modal approach performed by an experienced multi-disciplinary expert team. Optimal choice of the individual treatment modality according to disease localization and extent, tumour biology and patient factors is able to maintain quality of life, enables long-term survival and even cure in selected patients by a combination of chemotherapy and surgery. Treatment decisions must be based on the available evidence, which has been the basis for this consensus conference-based guideline delivering a clear proposal for diagnostic and treatment measures in each stage of rectal and colon cancer and the individual clinical situations. This ESMO guideline is recommended to be used as the basis for treatment and management decisions.

Trends in socioeconomic inequalities in cancer mortality in Barcelona: 1992–2003

Abstract Background The objective of this study was to assess trends in cancer mortality by educational level in Barcelona from 1992 to 2003. Methods The study population comprised Barcelona inhabitants aged 20 years or older. Data on cancer deaths were supplied by the system of information on mortality. Educational level was obtained from the municipal census. Age-standardized rates by educational level were calculated. We also fitted Poisson regression models to estimate the relative index of inequality (RII) and the Slope Index of Inequalities (SII). All were calculated for each sex and period (1992–1994, 1995–1997, 1998–2000, and 2001–2003). Results Cancer mortality was higher in men and women with lower educational level throughout the study period. Less-schooled men had higher mortality by stomach, mouth and pharynx, oesophagus, larynx and lung cancer. In women, there were educational inequalities for cervix uteri, liver and colon cancer. Inequalities of overall and specific types of cancer mortality remained stable in Barcelona; although a slight reduction was observed for some cancers. Conclusion This study has identified those cancer types presenting the greatest inequalities between men and women in recent years and shown that in Barcelona there is a stable trend in inequalities in the burden of cancer.

DNA repair mechanisms protect our genome from carcinogenesis

Human cells are constantly exposed to DNA damage. Without repair, damage can result in genetic instability and eventually cancer. The strong association between the lack of DNA damage repair, mutations and cancer is dramatically demonstrated by a number of cancer-prone human syndromes, such as xeroderma pigmentosum (XP), ataxia-telangiectasia (AT) and Fanconi anemia (FA). This review focuses on the historical discoveries related with these three diseases and describes their impact on the understanding of DNA repair mechanisms and the causes of human cancer. As deficiencies in DNA repair are also often related with progeria symptoms, unrepaired damage and aging are somehow related. Several other pathologies associated with DNA repair defects, genetic instability and increased cancer risk are also discussed. In fact, studies with cells from these many syndromes have helped in understanding important levels of protection against cancer and aging, although little help has actually been conferred to the patients in terms of therapy. Finally, the recent advances in combined basic and translational research on DNA repair and chemotherapy are presented.

The Carmaphycins: New Proteasome Inhibitors Exhibiting an alpha,beta-Epoxyketone Warhead from a Marine Cyanobacterium

Two new peptidic proteasome inhibitors were isolated as trace components from a Curacao collection of the marine cyanobacterium Symploca sp. Carmaphycin A (1) and carmaphycin B (2) feature a leucine-derived a,beta-epoxyketone warhead directly connected to either methionine sulfoxide or methionine sulfone. Their structures were elucidated on the basis of extensive NMR and MS analyses and confirmed by total synthesis, which in turn provided more material for further biological evaluations. Pure carmaphycins A and B were found to inhibit the beta 5 subunit (chymotrypsin-like activity) of the S. cerevisiae 20S proteasome in the low nanomolar range. Additionally, they exhibited strong cytotoxicity to lung and colon cancer cell lines, as well as exquisite antiproliferative effects in the NCI60 cell-line panel. These assay results as well as initial structural biology studies suggest a distinctive binding mode for these new inhibitors.

Chemopreventive effect of Copaifera langsdorffii leaves hydroalcoholic extract on 1,2-dimethylhydrazine-induced DNA damage and preneoplastic lesions in rat colon

Background Natural antioxidants present in common foods and beverages have drawn great attention to cancer prevention due to its health benefits, remarkable lack of toxicity and side effects. Copaifera langsdorffii, known as “copaiba”, “capaiva”, or “pau-de-óleo“, belongs to the Leguminosae family and occurs in fields and grasslands in the northern and northeastern parts of Brazil. Biological studies of Copaifera corroborate its widespread use by the population. This paper describes the effects of C. langsdorffii leaves hydroalcoholic extract on the 1,2-dimethylhydrazine (DMH)-induced DNA damage and aberrant crypt foci (ACF) in the colon of male Wistar rats. Methods The hydroalcoholic extract of C. langsdorffii was administered to rats by gavage at daily doses of 20, 40 and 80 mg/kg body weight. To evaluate DNA damage by the comet assay, animals received the C. langsdorffii extract for seven days and a single subcutaneous injection (sc) of 1,2-dimethylhydrazine (DMH) at a dose of 40 mg/kg on day 7. Animals were sacrificed 4 h after injection of DMH, to assess DNA damage. For the ACF assay, animals were acclimatized for one week (week 1) and then treated with the C. langsdorffii extract five times a week for four weeks (weeks 2 to 5). The rats received sc injections of DMH (40 mg/kg) on days 2 and 5 of weeks 2 and 3, to induce ACF. Animals were euthanized at week 5; i.e., four weeks after the first DMH treatment. Results Animals treated with different doses of the C. langsdorffii extract combined with DMH had significantly lower frequency of DNA damage as compared with the positive control (animals treated with DMH only). The percentage of reduction in the frequency of DNA damage ranged from 14.30% to 38.8%. The groups treated with 40 and 80 mg/kg C. langsdorffii extract during and after DMH treatment presented significantly lower numbers of ACF and aberrant crypts compared with the control. Conclusion The C. langsdorffii extract significantly reduced the extent of DNA damage and ACF induced by DMH, suggesting that the extract has a protective effect against colon carcinogenesis.