Impact of histologic subtype on cancer-specific survival in patients with renal cell carcinoma and tumor thrombus

BACKGROUND Although different prognostic factors for patients with renal cell carcinoma (RCC) and vena cava tumor thrombus (TT) have been studied, the prognostic value of histologic subtype in these patients remains unclear. OBJECTIVE We analyzed the impact of histologic subtype on cancer-specific survival (CSS). DESIGN, SETTINGS, AND PARTICIPANTS We retrospectively analyzed the records of 1774 patients with RCC and TT who underwent radical nephrectomy and tumor thrombectomy from 1971 to 2012 at 22 US and European centers. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Multivariable ordered logistic and Cox regression models were used to quantify the impact of tumor histology on CSS. RESULTS AND LIMITATIONS Overall 5-yr CSS was 53.4% (confidence interval [CI], 50.5-56.2) in the entire group. TT level (according to the Mayo classification of macroscopic venous invasion in RCC) was I in 38.5% of patients, II in 30.6%, III in 17.3%, and IV in 13.5%. Histologic subtypes were clear cell renal cell carcinoma (cRCC) in 89.9% of patients, papillary renal cell carcinoma (pRCC) in 8.5%, and chromophobe RCC in 1.6%. In univariable analysis, pRCC was associated with a significantly worse CSS (p<0.001) compared with cRCC. In multivariable analysis, the presence of pRCC was independently associated with CSS (hazard ratio: 1.62; CI, 1.01-2.61; p<0.05). Higher TT level, positive lymph node status, distant metastasis, and fat invasion were also independently associated with CSS. CONCLUSIONS In our multi-institutional series, we found that patients with pRCC and vena cava TT who underwent radical nephrectomy and tumor thrombectomy had significantly worse cancer-specific outcomes when compared with patients with other histologic subtypes of RCC. We confirmed that higher TT level and fat invasion were independently associated with reduced CSS.

T Cell Motility as Modulator of Interactions with Dendritic Cells

It is well established that the balance of costimulatory and inhibitory signals during interactions with dendritic cells (DCs) determines T cell transition from a naïve to an activated or tolerant/anergic status. Although many of these molecular interactions are well reproduced in reductionist in vitro assays, the highly dynamic motility of naïve T cells in lymphoid tissue acts as an additional lever to fine-tune their activation threshold. T cell detachment from DCs providing suboptimal stimulation allows them to search for DCs with higher levels of stimulatory signals, while storing a transient memory of short encounters. In turn, adhesion of weakly reactive T cells to DCs presenting peptides presented on major histocompatibility complex with low affinity is prevented by lipid mediators. Finally, controlled recruitment of CD8(+) T cells to cognate DC-CD4(+) T cell clusters shapes memory T cell formation and the quality of the immune response. Dynamic physiological lymphocyte motility therefore constitutes a mechanism to mitigate low avidity T cell activation and to improve the search for "optimal" DCs, while contributing to peripheral tolerance induction in the absence of inflammation.

Spatial proteomic and phospho-proteomic organization in three prototypical cell migration modes

BACKGROUND Tight spatio-temporal signaling of cytoskeletal and adhesion dynamics is required for localized membrane protrusion that drives directed cell migration. Different ensembles of proteins are therefore likely to get recruited and phosphorylated in membrane protrusions in response to specific cues. RESULTS HERE, WE USE AN ASSAY THAT ALLOWS TO BIOCHEMICALLY PURIFY EXTENDING PROTRUSIONS OF CELLS MIGRATING IN RESPONSE TO THREE PROTOTYPICAL RECEPTORS: integrins, recepor tyrosine kinases and G-coupled protein receptors. Using quantitative proteomics and phospho-proteomics approaches, we provide evidence for the existence of cue-specific, spatially distinct protein networks in the different cell migration modes. CONCLUSIONS The integrated analysis of the large-scale experimental data with protein information from databases allows us to understand some emergent properties of spatial regulation of signaling during cell migration. This provides the cell migration community with a large-scale view of the distribution of proteins and phospho-proteins regulating directed cell migration.

Cell mixing induced by myc is required for competitive tissue invasion and destruction

Cell-cell intercalation is used in several developmental processes to shape the normal body plan. There is no clear evidence that intercalation is involved in pathologies. Here we use the proto-oncogene myc to study a process analogous to early phase of tumour expansion: myc-induced cell competition. Cell competition is a conserved mechanism driving the elimination of slow-proliferating cells (so-called 'losers') by faster-proliferating neighbours (so-called 'winners') through apoptosis and is important in preventing developmental malformations and maintain tissue fitness. Here we show, using long-term live imaging of myc-driven competition in the Drosophila pupal notum and in the wing imaginal disc, that the probability of elimination of loser cells correlates with the surface of contact shared with winners. As such, modifying loser-winner interface morphology can modulate the strength of competition. We further show that elimination of loser clones requires winner-loser cell mixing through cell-cell intercalation. Cell mixing is driven by differential growth and the high tension at winner-winner interfaces relative to winner-loser and loser-loser interfaces, which leads to a preferential stabilization of winner-loser contacts and reduction of clone compactness over time. Differences in tension are generated by a relative difference in F-actin levels between loser and winner junctions, induced by differential levels of the membrane lipid phosphatidylinositol (3,4,5)-trisphosphate. Our results establish the first link between cell-cell intercalation induced by a proto-oncogene and how it promotes invasiveness and destruction of healthy tissues.

The stem cell gene "inhibitor of differentiation 1" (ID1) is frequently expressed in non-small cell lung cancer

Inhibitor of differentiation 1 (ID1) plays a role in cellular differentiation, proliferation, angiogenesis and tumor invasion. As shown recently, ID1 is positively regulated by the tyrosine kinase SRC in lung carcinoma cell lines and with that appears as a potential new therapeutic target in non-small cell carcinoma (NSCLC). To substantiate this hypothesis we examined ID1, SRC and matrix metalloproteinase-9 (MMP-9) immunohistochemically in human NSCLC specimens.

Do new biologics meet the unmet medical need in rheumatoid arthritis? Safety and efficacy of abatacept following B-cell depletion

Sir, anti TNF-α agents (aTNFs) are the most commonly prescribed biological agents in RA. More recently abatacept (ABA), a T-cell costimulation modulator, and rituximab (RTX), a monoclonal antibody directed against CD20, have become available. Observational studies suggest that switching to a new drug class may be more effective in uncontrolled RA than switching to a class of biologics to which the patient had unsuccessfully been exposed [1]. Information about the efficacy and safety of cycling strategies through third-line biologics is lacking. This study aimed to analyse the effectiveness and safety of switching patients to ABA as the third biological class after failure of aTNF plus RTX. The Swiss Clinical Quality Management (SCQM) programme for RA is a longitudinal population-based cohort, which has been approved by the local ethics committees of all participating centres [2]. For this analysis, we collected all the …

Critical roles for Rac GTPases in T-cell migration to and within lymph nodes

Naive T cells continuously recirculate between secondary lymphoid tissue via the blood and lymphatic systems, a process that maximizes the chances of an encounter between a T cell and its cognate antigen. This recirculation depends on signals from chemokine receptors, integrins, and the sphingosine-1-phosphate receptor. The authors of previous studies in other cell types have shown that Rac GTPases transduce signals leading to cell migration and adhesion; however, their roles in T cells are unknown. By using both 3-dimensional intravital and in vitro approaches, we show that Rac1- and Rac2-deficient T cells have multiple defects in this recirculation process. Rac-deficient T cells home very inefficiently to lymph nodes and the white pulp of the spleen, show reduced interstitial migration within lymph node parenchyma, and are defective in egress from lymph nodes. These mutant T cells show defective chemokine-induced chemotaxis, chemokinesis, and adhesion to integrin ligands. They have reduced lateral motility on endothelial cells and transmigrate in-efficiently. These multiple defects stem from critical roles for Rac1 and Rac2 in transducing chemokine and sphingosine-1-phosphate receptor 1 signals leading to motility and adhesion.

Tumor lymphangiogenesis and metastasis to lymph nodes induced by cancer cell expression of podoplanin

The membrane glycoprotein podoplanin is expressed by several types of human cancers and might be associated with their malignant progression. Its exact biological function and molecular targets are unclear, however. Here, we assessed the relevance of tumor cell expression of podoplanin in cancer metastasis to lymph nodes, using a human MCF7 breast carcinoma xenograft model. We found that podoplanin expression promoted tumor cell motility in vitro and, unexpectedly, increased tumor lymphangiogenesis and metastasis to regional lymph nodes in vivo, without promoting primary tumor growth. Importantly, high cancer cell expression levels of podoplanin correlated with lymph node metastasis and reduced survival times in a large cohort of 252 oral squamous cell carcinoma patients. Based on comparative transcriptional profiling of tumor xenografts, we identified endothelin-1, villin-1, and tenascin-C as potential mediators of podoplanin-induced tumor lymphangiogenesis and metastasis. These unexpected findings identify a novel mechanism of tumor lymphangiogenesis and metastasis induced by cancer cell expression of podoplanin, suggesting that reagents designed to interfere with podoplanin function might be developed as therapeutics for patients with advanced cancer.

Lymph node dissection in renal cell carcinoma

Although lymphadenectomy (lymph node dissection [LND]) is currently accepted as the most accurate and reliable staging procedure for the detection of lymph node invasion (LNI), its therapeutic benefit in renal cell carcinoma (RCC) still remains controversial.

In vivo analysis of uropod function during physiological T cell trafficking

Migrating lymphocytes acquire a polarized phenotype with a leading and a trailing edge, or uropod. Although in vitro experiments in cell lines or activated primary cell cultures have established that Rho-p160 coiled-coil kinase (ROCK)-myosin II-mediated uropod contractility is required for integrin de-adhesion on two-dimensional surfaces and nuclear propulsion through narrow pores in three-dimensional matrices, less is known about the role of these two events during the recirculation of primary, nonactivated lymphocytes. Using pharmacological antagonists of ROCK and myosin II, we report that inhibition of uropod contractility blocked integrin-independent mouse T cell migration through narrow, but not large, pores in vitro. T cell crawling on chemokine-coated endothelial cells under shear was severely impaired by ROCK inhibition, whereas transendothelial migration was only reduced through endothelial cells with high, but not low, barrier properties. Using three-dimensional thick-tissue imaging and dynamic two-photon microscopy of T cell motility in lymphoid tissue, we demonstrated a significant role for uropod contractility in intraluminal crawling and transendothelial migration through lymph node, but not bone marrow, endothelial cells. Finally, we demonstrated that ICAM-1, but not anatomical constraints or integrin-independent interactions, reduced parenchymal motility of inhibitor-treated T cells within the dense lymphoid microenvironment, thus assigning context-dependent roles for uropod contraction during lymphocyte recirculation.

Hostile takeover by Plasmodium: reorganization of parasite and host cell membranes during liver stage egress

The protozoan parasite Plasmodium is transmitted by female Anopheles mosquitoes and undergoes obligatory development within a parasitophorous vacuole in hepatocytes before it is released into the bloodstream. The transition to the blood stage was previously shown to involve the packaging of exoerythrocytic merozoites into membrane-surrounded vesicles, called merosomes, which are delivered directly into liver sinusoids. However, it was unclear whether the membrane of these merosomes was derived from the parasite membrane, the parasitophorous vacuole membrane or the host cell membrane. This knowledge is required to determine how phagocytes will be directed against merosomes. Here, we fluorescently label the candidate membranes and use live cell imaging to show that the merosome membrane derives from the host cell membrane. We also demonstrate that proteins in the host cell membrane are lost during merozoite liberation from the parasitophorous vacuole. Immediately after the breakdown of the parasitophorous vacuole membrane, the host cell mitochondria begin to degenerate and protein biosynthesis arrests. The intact host cell plasma membrane surrounding merosomes allows Plasmodium to mask itself from the host immune system and bypass the numerous Kupffer cells on its way into the bloodstream. This represents an effective strategy for evading host defenses before establishing a blood stage infection.

Theileria annulata promotes Src kinase-dependent host cell polarization by manipulating actin dynamics in podosomes and lamellipodia

Theileria annulata is an intracellular protozoan parasite that infects B cells and macrophages of ruminants. Macrophages infected with T. annulata are de-differentiated and display tumour cell properties and a metastatic behaviour. How parasitized cells adapt their morphology, motility and invasive behaviour has not yet been addressed in detail. In this study, I investigated the regulation of host cell actin dynamics in T. annulata-transformed macrophages and how this affects host cell morphology and motility. T. annulata was found to promote the formation of filamentous-actin-rich podosome-type adhesions (PTAs) and lamellipodia, and to establish a polarized morphology of the infected cell. Characteristic for parasite-dependent host cell polarization is that infected cells display a single, persistent lamellipodium. Src kinases--in particular Hck--are required for the polar extension of this lamellipodium. Hck does so by promoting the clustered assembly of PTAs and accumulation of proteins of the Ezrin, Radixin, Moesin (ERM) family in lamellipodia. Polar accumulation of PTAs and ERM proteins correlates with focal matrix degradation underneath lamellipodia. These findings suggest that T. annulata equips its host cell with properties to adhere and invade. These properties are likely to promote the motile behaviour required for dissemination of infected cells in vivo.

Echinococcus multilocularis phosphoglucose isomerase (EmPGI): a glycolytic enzyme involved in metacestode growth and parasite-host cell interactions

In Echinococcus multilocularis metacestodes, the surface-associated and highly glycosylated laminated layer, and molecules associated with this structure, is believed to be involved in modulating the host-parasite interface. We report on the molecular and functional characterisation of E. multilocularis phosphoglucose isomerase (EmPGI), which is a component of this laminated layer. The EmPGI amino acid sequence is virtually identical to that of its homologue in Echinococcus granulosus, and shares 64% identity and 86% similarity with human PGI. Mammalian PGI is a multi-functional protein which, besides its glycolytic function, can also act as a cytokine, growth factor and inducer of angiogenesis, and plays a role in tumour growth, development and metastasis formation. Recombinant EmPGI (recEmPGI) is also functionally active as a glycolytic enzyme and was found to be present, besides the laminated layer, in vesicle fluid and in germinal layer cell extracts. EmPGI is released from metacestodes and induces a humoral immune response in experimentally infected mice, and vaccination of mice with recEmPGI renders these mice more resistant towards secondary challenge infection, indicating that EmPGI plays an important role in parasite development and/or in modulating the host-parasite relationship. We show that recEmPGI stimulates the growth of isolated E. multilocularis germinal layer cells in vitro and selectively stimulates the proliferation of bovine adrenal cortex endothelial cells but not of human fibroblasts and rat hepatocytes. Thus, besides its role in glycolysis, EmPGI could also act as a factor that stimulates parasite growth and potentially induces the formation of novel blood vessels around the developing metacestode in vivo.

Meprinα transactivates the epidermal growth factor receptor (EGFR) via ligand shedding, thereby enhancing colorectal cancer cell proliferation and migration

Meprinα, an astacin-type metalloprotease is overexpressed in colorectal cancer cells and is secreted in a non-polarized fashion, leading to the accumulation of meprinα in the tumor stroma. The transition from normal colonocytes to colorectal cancer correlates with increased meprinα activity at primary tumor sites. A role for meprinα in invasion and metastatic dissemination is supported by its pro-angiogenic and pro-migratory activity. In the present study, we provide evidence for a meprinα-mediated transactivation of the EGFR signaling pathway and suggest that this mechanism is involved in colorectal cancer progression. Using alkaline phosphatase-tagged EGFR ligands and an ELISA assay, we demonstrate that meprinα is capable of shedding epidermal growth factor (EGF) and transforming growth factor-α (TGFα) from the plasma membrane. Shedding was abrogated using actinonin, an inhibitor for meprinα. The physiological effects of meprinα-mediated shedding of EGF and TGFα were investigated with human colorectal adenocarcinoma cells (Caco-2). Proteolytically active meprinα leads to an increase in EGFR and ERK1/2 phosphorylation and subsequently enhances cell proliferation and migration. In conclusion, the implication of meprinα in the EGFR/MAPK signaling pathway indicates a role of meprinα in colorectal cancer progression.