The complexity of neutrophils in health and disease: Focus on cancer.

Neutrophils are essential soldiers of the immune response and their role have long been restricted to their activities in defence against microbial infections and during the acute phase of the inflammatory response. However, increasing number of investigations showed that neutrophils are endowed with plasticity and can participate in the orchestration of both innate and adaptive immune responses. Neutrophils have an impact on a broad range of disorders, including infections, chronic inflammations, and cancer. Neutrophils are present in the tumour microenvironment and have been reported to mediate both pro-tumour and anti-tumour responses. Neutrophils can contribute to genetic instability, tumour cell proliferation, angiogenesis and suppression of the anti-tumour immune response. In contrast, neutrophils are reported to mediate anti-tumour resistance by direct killing of tumour cells or by engaging cooperative interactions with other immune cells. Here we discuss the current understandings of neutrophils biology and functions in health and diseases, with a specific focus on their role in cancer biology and their prognostic significance in human cancer.

Blockade of α4 integrins reduces leukocyte-endothelial interactions in cerebral vessels and improves memory in a mouse model of Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline associated with the deposition of amyloid-ß (Aß) plaques, hyperphosphorylation of tau protein, and neuronal loss. Vascular inflammation and leukocyte trafficking may contribute to AD pathogenesis, and a better understanding of these inflammation mechanisms could therefore facilitate the development of new AD therapies. Here we show that T cells extravasate in the proximity of cerebral VCAM-1+ vessels in 3xTg-AD transgenic mice, which develop both Aß and tau pathologies. The counter-ligand of VCAM-1 - α4ß1 integrin, also known as very late antigen-4 (VLA-4) - was more abundant on circulating CD4+ T cells and was also expressed by a significant proportion of blood CD8+ T cells and neutrophils in AD mice. Intravital microscopy of the brain microcirculation revealed that α4 integrins control leukocyte-endothelial interactions in AD mice. Therapeutic targeting of VLA-4 using antibodies that specifically block α4 integrins improved the memory of 3xTg-AD mice compared to an isotype control. These antibodies also reduced neuropathological hallmarks of AD, including microgliosis, Aß load and tau hyperphosphorylation. Our results demonstrate that α4 integrin-dependent leukocyte trafficking promotes cognitive impairment and AD neuropathology, suggesting that the blockade of α4 integrins may offer a new therapeutic strategy in AD.

Cancer-related CD15/FUT4 overexpression decreases benefit to agents targeting EGFR or VEGF acting as a novel RAF-MEK-ERK kinase downstream regulator in metastatic colorectal cancer.

BACKGROUND: Cancer-related immune antigens in the tumor microenvironment could represent an obstacle to agents targeting EGFR "cetuximab" or VEGF "bevacizumab" in metastatic colorectal cancer (mCRC) patients. METHODS: Infiltrating immune cells into tumor tissues, cancer-related expression of immune antigens (CD3, CD8, CD68, CD73, MPO, CD15/FUT4) from 102 mCRC patients receiving first-line Cetuximab or Bevacizumab plus chemotherapy were assessed by immunohistochemistry and validated in an independent tissue microarrays of 140 patients. Genome-wide expression profiles from 436 patients and 60 colon cancer cell lines were investigated using bioinformatics analysis. In vitro kinase assays of target genes activated by chemokines or growth factors were performed. RESULTS: Here, we report that cancer-related CD15/FUT4 is overexpressed in most of mCRCs patients (43 %) and associates with lower intratumoral CD3+ and CD8+ T cells, higher systemic inflammation (NLR at diagnosis >5) and poorer outcomes, in terms of response and progression-free survival than those CD15/FUT4-low or negative ones (adjusted hazard ratio (HR) = 2.92; 95 % CI = 1.86-4.41; P < 0.001). Overexpression of CD15/FUT4 is induced through RAF-MEK-ERK kinase cascade, suppressed by MEK inhibitors and exhibits a close connection with constitutive oncogenic signalling pathways that respond to ERBB3 or FGFR4 activation (P < 0.001). CD15/FUT4-high expressing colon cancer cells with primary resistance to cetuximab or bevacizumab are significantly more sensitive to MEK inhibitors than CD15/FUT4-low counterparts. CONCLUSION: Cancer-related CD15/FUT4 overexpression participates in cetuximab or bevacizumab mechanisms of resistance in mCRC patients. CD15/FUT4 as a potential target of the antitumor immune response requires further evaluation in clinical studies.

Risk of prostate cancer and thrombosis-related factor polymorphisms.

Venous thromboembolism (VTE) is a complication commonly encountered in cancer patients and is considered to be a major cause of morbidity and mortality. The genetic polymorphisms of thrombophilic factors in cancer patients have been focused on during the last few years. However, the number of available studies on the association between prostate cancer and thromboembolic diseases is limited. Prostate cancer is one of the four major types of cancer and its development is affected by a variety of environmental and genetic factors. In the present study we aimed to focus on the effects of thromboembolic factor gene variations on the risk of prostate cancer. In order to conduct our prospective study, we used amplification-refractory mutation system-polymerase chain reaction to investigate three polymorphisms [factor V Leiden (FVL) G1691A, factor II (prothrombin, PTH) G20210A and methylenetetrahydrofolate reductase (MTHFR) C677T] in prostate cancer patients, via comparison with normal individuals. The results demonstrated no significant differences in FVL and PTH gene variations between cases and controls (P>0.05). Although some cases with the T allele of MTHFR 677 were identified, no significant solidarity was established by statistical analysis (P>0.05). Therefore, non-genetic factors that may disturb homeostatic balance should also be considered in future studies, in order to determine the exact association between VTE and prostate cancer.