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IntroductionCirculating monocytes are precursors that can differentiate into a variety of tissue-resident macrophages (M⌽s) or dendritic cells (DCs), and even osteoclasts. 1 M⌽s exhibit a variety of activities, some of which are in opposition (ie, proinflammatory versus anti-inflammatory, immunostimulatory versus immunosuppressive, and tissue destructive versus reconstructive). 1 The functional heterogeneity of M⌽s depends, at least in part, on the local microenvironment. 2,3 In analogy with the Th1/Th2 dichotomy of T-cell responses, M⌽s exposed to IFN␥ or IL-4 have been referred to as M1s or M2s (also called alternatively activated M⌽s), respectively. 4 M1s produce IL-12 and TNF␣ and are potent killers of microorganisms (especially intracellular pathogens) and tumor cells. M2s produce IL-10 but not IL-12, scavenge debris, tune inflammatory responses, and promote humoral immunity and tissue repair. 5 The detection in cancer patients of tumor-specific T cells that kill ex vivo autologous tumor cells demonstrates that numerous tumor-cell types are potentially immunogenic. However, spontaneous clearance of established tumors by immune mechanisms is rare and active antitumor immunotherapy usually has poor clinical efficacy. 6 It is now largely documented that established tumors propagate conditions that favor their immune escape. 6 Tumor-associated macrophages (TAMs) and regulatory T cells (Tregs) accumulate at tumor sites and maintain immune tolerance that contributes to defeating tumor immunity. 6,7 TAMs are far more abundant than Tregs and, in various solid tumors, constitute the major components of the leukocyte infiltrate. In most cases, especially breast, prostate, cervical, and ovarian cancers, TAM density is correlated with poor prognosis. [8][9][10] Strong evidence suggests that TAMs also promote cancer progression and metastasis. 8,11,12 TAMs are polarized M2 cells with potent immunosuppressive functions. They have poor antigen-presenting capacity, prevent T-cell activation, and may contribute to suppressing DC functions. 4,13,14 They also promote the recruitment of Tregs and Th2 cells (through CC chemokine ligand 17 [CCL17] and CCL22 secretion) and naive T cells (through CCL18). Naive T-cell activation, in an environment dominated by immature DCs and TAMs, is likely to induce anergy. 10,15 In addition, TAM production of growth and angiogenic factors (ie, vascular endothelial growth factor [VEGF] and platelet-derived endothelial cell growth factor [PDGF]), proteases (ie, matrix metalloproteinase 9 [MMP9]), and chemokines (eg, CCL2) favors tumor-cell proliferation, angiogenesis, dissolution of connective tissues, and metastasis. 8,12,14,16 The origin of TAMs has mostly been studied in mice in terms of precursor recruitment, survival, and proliferation. TAMs derive from circulating monocytes that are recruited into tumors by chemotactic factors, such as monocyte-colony-stimulating factor Submitted February 19, 2007; accepted August 29, 2007. Prepublished online as Blood First Edition paper, September 11, 2...

Tumor-associated macrophages (TAM) are M2d-polarized cells (IL-10 high , IL-12 low , ILT3 high , CD86 low ) that accumulate in tumor microenvironment. TAM inhibit antitumor T lymphocyte generation and function, contribute to tumor tolerance and are trophic for tumors. In this study, we investigated whether some immunological factors may reverse TAM immunosuppressive properties. Among 32 cytokines, we have identified IFNc on its ability to switch immunosuppressive TAM into immunostimulatory cells. Upon IFNc exposure, TAM purified from ovarian cancer ascites recover a M1 phenotype (IL-10 low , IL-12 high ), express high levels of CD86 and low levels of ILT3, enhance the proliferation of CD4 1 T lymphocytes and potentiate the cytotoxic properties of a MelanA-specific CD8 1 T cell clone. IFNc-treated TAM also secreted reduced levels of mediators promoting suppressive T cell accumulation (CCL18) and trophic for tumors (VEGF and MMP9). As TAM derive from the local differentiation of peripheral blood monocytes, we investigated whether IFNc may also affect TAM generation. In the presence of ovarian ascites, IFNc skewed monocyte differentiation from TAM-like cells to M1-polarized immunostimulatory macrophages. Together, these data show that IFNc overcomes TAM-induced immunosuppression by preventing TAM generation and functions. These data highlight that IFNc used locally at the tumor site could potentiate the efficacy of antitumor immunotherapies based on the generation of effector T cells. ' 2009 UICC

Purpose Metastasis and drug resistance are the major limitations in the survival and management of cancer patients. This study aimed to identify the mechanisms underlying HT29 colon cancer cell chemoresistance acquired after sequential exposure to 5-fluorouracil (5FU), a classical anticancer drug for treatment of epithelial solid tumors. We examined its clinical relevance in a cohort of colon cancer patients with liver metastases after 5FU-based neoadjuvant chemotherapy and surgery. Results We show that a clonal 5F31 cell population, resistant to 1μM 5FU, express a typical cancer stem cell-like phenotype and enter into a reversible quiescent G0-state upon re-exposure to higher 5FU concentrations. These quiescent cells overexpressed the tyrosine kinase c-Yes that became activated and membrane-associated upon 5FU exposure. This enhanced signaling pathway induced the dissociation of the Yes/YAP (Yes-associated protein) molecular complex and depleted nuclear YAP levels. Consistently, c-Yes silencing decreased nuclear YAP accumulation and induced cellular quiescence in 5F31 cells cultured in 5FU-free medium. Importantly, c-Yes and YAP transcript levels were higher in liver metastases of colon cancer patients after 5FU-based neoadjuvant chemotherapy. Moreover, the c-Yes and YAP levels positively correlated with colon cancer relapse and shorter patient survival (p<0.05 and p<0.025, respectively). Conclusions We identified c-Yes and YAP as potential molecular targets to eradicate quiescent cancer cells and dormant micrometastases during 5FU chemotherapy and resistance and as predictive survival markers for colon cancer.

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The fluorinated analog of deoxycytidine, Gemcitabine (Gemzar), is the main chemotherapeutic drug in pancreatic cancer, but survival remains weak mainly because of the high resistance of tumors to the drug. Recent works have shown that the mucin MUC4 may confer an advantage to pancreatic tumor cells by modifying their susceptibility to drugs. However, the cellular mechanism(s) responsible for this MUC4-mediated resistance is unknown. The aim of this work was to identify the cellular mechanisms responsible for gemcitabine resistance linked to MUC4 expression. CAPAN-2 and CAPAN-1 adenocarcinomatous pancreatic cancer (PC) cell lines were used to establish stable MUC4-deficient clones (MUC4-KD) by shRNA interference. Measurement of the IC 50 index using tetrazolium salt test indicated that MUC4-deficient cells were more sensitive to gemcitabine. This was correlated with increased Bax/Bcl XL ratio and apoptotic cell number. Expression of Equilibrative/Concentrative Nucleoside Transporter (hENT1, hCNT1/3), deoxycytidine kinase (dCK), ribonucleotide reductase (RRM1/2) and Multidrug-Resistance Protein (MRP3/4/5) was evaluated by quantitative RT-PCR (qRT-PCR) and western blotting. Alteration of MRP3, MRP4, hCNT1 and hCNT3 expression was observed in MUC4-KD cells, but only hCNT1 alteration was correlated to MUC4 expression and sensitivity to gemcitabine. Decreased activation of MAPK, JNK and NF-kB pathways was observed in MUC4-deficient cells, in which the NF-kB pathway was found to have an important role in both sensitivity to gemcitabine and hCNT1 regulation. Finally, and in accordance with our in vitro data, we found that MUC4 expression was conversely correlated to that of hCNT1 in tissues from patients with pancreatic adenocarcinoma. This work describes a new mechanism of PC cell resistance to gemcitabine, in which the MUC4 mucin negatively regulates the hCNT1 transporter expression via the NF-kB pathway. Altogether, these data point out to MUC4 and hCNT1 as potential targets to ameliorate the response of pancreatic tumors to gemcitabine treatment.

A regimen consisting of 5-fluorouracil/leucovorin plus oxaliplatin (FOLFOX-6) is widely used in France in the first-line treatment of metastatic colorectal cancer (MCRC). The aim of our study was to demonstrate the non-inferiority of capecitabine plus oxaliplatin (XELOX) versus FOLFOX-6 for this indication. Patients were randomly assigned to receive XELOX or FOLFOX-6 for 6 months. The primary endpoint was overall response rate (ORR) in the per-protocol (PP) population; however, progression-free and overall survival (OS), time to response and response duration were also assessed. A total of 306 patients were enrolled (XELOX n 5 156; FOLFOX-6 n 5 150). ORR was 42 and 46% with XELOX and FOLFOX-6, respectively, in the PP population. The difference between groups was 4.7%; the upper limit of the unilateral 95% confidence interval (14.4%) was below the non-inferiority margin of 15%. In the intent-to-treat population, median progression-free survival was 8.8 months with XELOX and 9.3 months with FOLFOX-6, and median OS was 19.9 and 20.5 months, respectively. XELOX patients had significantly more grade 3/4 thrombocytopenia (12% vs. 5%) and diarrhoea (14% vs. 7%), but significantly less grade 3/4

SUMMARY BackgroundSorafenib increases median survival and time to radiological progression in patients with advanced hepatocellular carcinoma, but its benefit for ChildPugh B patients remains uncertain.