NR2F2 controls malignant squamous cell carcinoma state by promoting stemness and invasion and repressing differentiation.

The nongenetic mechanisms required to sustain malignant tumor state are poorly understood. During the transition from benign tumors to malignant carcinoma, tumor cells need to repress differentiation and acquire invasive features. Using transcriptional profiling of cancer stem cells from benign tumors and malignant skin squamous cell carcinoma (SCC), we identified the nuclear receptor NR2F2 as uniquely expressed in malignant SCC. Using genetic gain of function and loss of function in vivo, we show that NR2F2 is essential for promoting the malignant tumor state by controlling tumor stemness and maintenance in mouse and human SCC. We demonstrate that NR2F2 promotes tumor cell proliferation, epithelial-mesenchymal transition and invasive features, while repressing tumor differentiation and immune cell infiltration by regulating a common transcriptional program in mouse and human SCCs. Altogether, we identify NR2F2 as a key regulator of malignant cancer stem cell functions that promotes tumor renewal and restricts differentiation to sustain a malignant tumor state.

Results of the Belgian expanded access program of eribulin in the treatment of metastatic breast cancer closely mirror those of the pivotal phase III trial.

BACKGROUND: Eribulin is a non-taxane microtubule dynamics inhibitor that showed a survival benefit versus treatment of physician's choice in a phase III trial enrolling patients with metastatic breast cancer (MBC). METHODS: The E7389-G000-398 trial was designed to provide eribulin to MBC patients pre-treated with anthracylines, taxanes and capecitabine. Patient characteristics, efficacy and safety data were collected prospectively. Efficacy and survival analyses were performed using retrospectively collected data of patients treated at a single institution. RESULTS: One hundred fifty-four patients were enrolled and the median number of previous lines of chemotherapy was 4. The most frequent adverse events were fatigue/asthenia (74%), alopecia (55%), peripheral neuropathy (46%) and neutropenia (43%). Objective response rate (ORR) was 24% in the evaluable population and 14% in patients pre-treated with both taxanes and vinorelbine. In patients with oestrogen receptor (ER)+/human epidermal growth factor receptor 2 (HER2)- MBC, response rate was 29% and 21% with triple-negative disease. Activity was minimal in HER2+ MBC treated with eribulin monotherapy (14% ORR). Median progression-free survival was 3.2 months. Median overall survival was 11.3 months; 77% of patients were alive at 6 months and 43% at 12 months. CONCLUSION: Eribulin was active in MBC patients with a high tumour burden and predominant visceral disease. Safety profile was similar to what was reported in the phase III trials. Prophylactic granulocyte colony-stimulating factor administration allowed optimal dose intensity and could have contributed to the recorded response rate. Activity is sustained after treatment with taxanes and vinorelbine. The recently investigated combination of eribulin and trastuzumab should lead to higher activity in HER2-positive MBC.

Significance of N-terminal proteolysis of CCL14a to activity on the chemokine receptors CCR1 and CCR5 and the human cytomegalovirus-encoded chemokine receptor US28.

The CC chemokine CCL14a is constitutively expressed in a large variety of tissues and its inactive proform CCL14a(1-74) circulates in high concentrations in plasma. CCL14a(1-74) is converted into CCL14a(9-74) by the proteases urokinase-type plasminogen activator and plasmin and is a highly active agonist for the chemokine receptors CCR1 and CCR5. In this study, a new CCL14a analog, CCL14a(12-74), was isolated from blood filtrate. To elucidate the functional role of the N terminus, a panel of N-terminally truncated CCL14a analogs were tested on the receptors CCR1 to CCR5 and on the human cytomegalovirus (HCMV)-encoded chemokine receptor US28. The rank order of binding affinity to these receptors and of the activation of CCR1 and CCR5-mediated intracellular Ca(2+) concentration mobilization is CCL14a(6-74)<(7-74)<(8-74)<<(9-74) = (10-74)>>(11-74)>>(12-74). The almost identical affinities of CCL14a(7-74), CCL14a(9-74), and CCL14a(10-74) for the US28 receptor and the inhibition of US28-mediated HIV infection of 293T cells by all of the N-terminally truncated CCL14a analogs support the promiscuous nature of the viral chemokine receptor US28. In high concentrations, CCL14a(12-74) did reveal antagonistic activity on intracellular Ca(2+) concentration mobilization in CCR1- and CCR5-transfected cells, which suggests that truncation of Tyr(11) might be of significance for an efficient inactivation of CCL14a. A putative inactivation pathway of CCL14a(9-74) to CCL14a(12-74) may involve the dipeptidase CD26/dipeptidyl peptidase IV (DPPIV), which generates CCL14a(11-74), and the metalloprotease aminopeptidase N (CD13), which displays the capacity to generate CCL14a(12-74) from CCL14a(11-74). Our results suggest that the activity of CCL14a might be regulated by stringent proteolytic activation and inactivation steps.

Quantum proteolytic activation of chemokine CCL15 by neutrophil granulocytes modulates mononuclear cell adhesiveness.

Monocyte infiltration into inflammatory sites is generally preceded by neutrophils. We show here that neutrophils may support this process by activation of CCL15, a human chemokine circulating in blood plasma. Neutrophils were found to release CCL15 proteolytic activity in the course of hemofiltration of blood from renal insufficiency patients. Processing of CCL15 immunoreactivity (IR) in the pericellular space is suggested by a lack of proteolytic activity in blood and blood filtrate, but a shift of the retention time (t(R)) of CCL15-IR, detected by chromatographic separation of CCL15-IR in blood and hemofiltrate. CCL15 molecules with N-terminal deletions of 23 (delta23) and 26 (delta26) aa were identified as main proteolytic products in hemofiltrate. Neutrophil cathepsin G was identified as the principal protease to produce delta23 and delta26 CCL15. Also, elastase displays CCL15 proteolytic activity and produces a delta21 isoform. Compared with full-length CCL15, delta23 and delta26 isoforms displayed a significantly increased potency to induce calcium fluxes and chemotactic activity on monocytes and to induce adhesiveness of mononuclear cells to fibronectin. Thus, our findings indicate that activation of monocytes by neutrophils is at least in part induced by quantum proteolytic processing of circulating or endothelium-bound CCL15 by neutrophil cathepsin G.