[Show abstract][Hide abstract] ABSTRACT: Aggressive tumor cells can obtain the ability to transdifferentiate into cells with endothelial features and thus form vasculogenic networks. This phenomenon, called vasculogenic mimicry (VM), is associated with increased tumor malignancy and poor clinical outcome. To identify novel key molecules implicated in the process of vasculogenic mimicry, microarray analysis was performed to compare gene expression profiles of aggressive (VM+) and non-aggressive (VM-) cells derived from Ewing sarcoma and breast carcinoma. We identified the CD44/c-Met signaling cascade as heavily relevant for vasculogenic mimicry. CD44 was at the center of this cascade, and highly overexpressed in aggressive tumors. Both CD44 standard isoform and its splice variant CD44v6 were linked to increased aggressiveness in VM. Since VM is most abundant in Ewing sarcoma tumors functional analyses were performed in EW7 cells. Overexpression of CD44 allowed enhanced adhesion to its extracellular matrix ligand hyaluronic acid. CD44 expression also facilitated the formation of vasculogenic structures in vitro, as CD44 knockdown experiments repressed migration and vascular network formation. From these results and the observation that CD44 expression is associated with vasculogenic structures and blood lakes in human Ewing sarcoma tissues, we conclude that CD44 increases aggressiveness in tumors through the process of vasculogenic mimicry.
[Show abstract][Hide abstract] ABSTRACT: Two bifunctional ruthenium(II)-p-cymene complexes with perfluorinated side chains, attached via pyridine ligands, have been evaluated in a series of in vitro and in vivo assays. Their effects on human endothelial (ECRF24 and HUVEC) cells, non-cancerous human embryonic kidney (HEK-293) cells and various human tumor cells were investigated. The complex with the shorter chain, 1, inhibits the proliferation of the tumor cell lines and ECRF24, whereas 2, selectively inhibits ECRF24 and HUVEC proliferation. Neither of them inhibits the migration of ECRF24 cells whereas both compounds inhibit sprout formation in HUVEC cells. Using three preclinical models, i.e. vasculature formation in the chorioallantoic membrane (CAM) of the chicken embryo, human A2780 ovarian carcinoma tumors xenografted on the CAM and human LS174T colorectal adenocarcinoma tumors grown in athymic mice, the angiostatic and anticancer activities of these two complexes were studied. Overall, 1 inhibited tumor growth predominantly through an anticancer effect whereas 2 inhibited tumor growth predominately via an anti-angiogenic mechanism.
[Show abstract][Hide abstract] ABSTRACT: The tumour microenvironment comprises a network of immune response and vascularization factors. From this network, we identified immunological and vascularization gene expression clusters and the correlations between the clusters. We subsequently determined which factors were correlated with patient survival in cervical carcinoma.
The expression of 42 genes was investigated in 52 fresh frozen squamous cervical cancer samples by qRT-PCR. Weighted gene co-expression network analysis and mixed-model analyses were performed to identify gene expression clusters. Correlations and survival analyses were further studied at expression cluster and single gene level.
We identified four immune response clusters: ‘T cells’ (CD3E/CD8A/TBX21/IFNG/FOXP3/IDO1), ‘Macrophages’ (CD4/CD14/CD163), ‘Th2’ (IL4/IL5/IL13/IL12) and ‘Inflammation’ (IL6/IL1B/IL8/IL23/IL10/ARG1) and two vascularization clusters: ‘Angiogenesis’ (VEGFA/FLT1/ANGPT2/ PGF/ICAM1) and ‘Vessel maturation’ (PECAM1/VCAM1/ANGPT1/SELE/KDR/LGALS9). The ‘T cells’ module was correlated with all modules except for ‘Inflammation’, while ‘Inflammation’ was most significantly correlated with ‘Angiogenesis’ (p < 0.001). High expression of the ‘T cells’ cluster was correlated with earlier TNM stage (p = 0.007). High CD3E expression was correlated with improved disease-specific survival (p = 0.022), while high VEGFA expression was correlated with poor disease-specific survival (p = 0.032). Independent predictors of poor disease-specific survival were IL6 (hazard ratio = 2.3, p = 0.011) and a high IL6/IL17 ratio combined with low IL5 expression (hazard ratio = 4.2, p = 0.010).
‘Inflammation’ marker IL6, especially in combination with low levels of IL5 and IL17, was correlated with poor survival. This suggests that IL6 promotes tumour growth, which may be suppressed by a Th17 and Th2 response. Measuring IL6, IL5 and IL17 expression may improve the accuracy of predicting prognosis in cervical cancer.
Molecular Cancer 03/2015; 14(1). DOI:10.1186/s12943-015-0350-0 · 4.26 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Drug combinations can improve angiostatic cancer treatment efficacy and enable the reduction of side effects and drug resistance. Combining drugs is non-trivial due to the high number of possibilities. We applied a feedback system control (FSC) technique with a population-based stochastic search algorithm to navigate through the large parametric space of nine angiostatic drugs at four concentrations to identify optimal low-dose drug combinations. This implied an iterative approach of in vitro testing of endothelial cell viability and algorithm-based analysis. The optimal synergistic drug combination, containing erlotinib, BEZ-235 and RAPTA-C, was reached in a small number of iterations. Final drug combinations showed enhanced endothelial cell specificity and synergistically inhibited proliferation (p < 0.001), but not migration of endothelial cells, and forced enhanced numbers of endothelial cells to undergo apoptosis (p < 0.01). Successful translation of this drug combination was achieved in two preclinical in vivo tumor models. Tumor growth was inhibited synergistically and significantly (p < 0.05 and p < 0.01, respectively) using reduced drug doses as compared to optimal single-drug concentrations. At the applied conditions, single-drug monotherapies had no or negligible activity in these models. We suggest that FSC can be used for rapid identification of effective, reduced dose, multi-drug combinations for the treatment of cancer and other diseases.
[Show abstract][Hide abstract] ABSTRACT: Following the identification of [Ru(η6-p-cymene)Cl2(1H,1H,2H,2H-perfluorodecyl-3-(pyridin-3-yl)propanoate)], a ruthenium(II)-arene complex with a perfluoroalkyl-modified ligand, that displays remarkable in vitro cancer cell selectivity, a series of structurally related compounds were designed. In the new derivatives, the p-cymene ring and/or the chloride ligands are substituted by other ligands to modulate the steric bulk or aquation kinetics. The new compounds were evaluated in both in vitro (cytotoxicity and migration assays) and in vivo (chicken chorioallantoic membrane) models and were found to exhibit potent antivascular effects.
[Show abstract][Hide abstract] ABSTRACT: Hyperthermia used as an adjuvant with chemotherapy is highly promising in the treatment of certain
cancers. Currently, the small molecule drugs used in combination with hyperthermia were not designed
for this application. Herein, we report the evaluation of a chlorambucil and a ruthenium compound
modified with a long fluorous chain, which exhibit thermoresponsive activity in colorectal
adenocarcinoma xenografts in athymic mice in combination with mild hyperthermia (42°C).
Intraperitoneal injection of the derivatives followed by local hyperthermia showed a synergistic tumor
growth reduction by 79% and 90% for the chlorambucil and ruthenium-based derivatives, respectively,
with the latter exhibiting a higher synergy in combination with hyperthermia compared to the
monotherapies. Histological analysis shows that both derivatives in combination with hyperthermia
significantly decrease the number of proliferating tumor cells.
[Show abstract][Hide abstract] ABSTRACT: The concept of antiangiogenic therapy in cancer treatment has led to the approval of different agents, most of them targeting the well known vascular endothelial growth factor pathway. Despite promising results in preclinical studies, the efficacy of antiangiogenic therapy in the clinical setting remains limited. Recently, awareness has emerged on resistance to antiangiogenic therapies. It has become apparent that the intricate complex interplay between tumors and stromal cells, including endothelial cells and associated mural cells, allows for escape mechanisms to arise that counteract the effects of these targeted therapeutics. Here, we review and discuss known and novel mechanisms that contribute to resistance against antiangiogenic therapy and provide an outlook to possible improvements in therapeutic approaches.
[Show abstract][Hide abstract] ABSTRACT: Tumor vasculature is known to be poorly organized leading to increased leakage of molecules to the
extravascular space. This process can potentially increase interstitial fluid pressure impairing intra-tumoral
blood flow and oxygen supply, and can affect drug uptake. Anti-angiogenic therapies are believed to reduce
vascular permeability, potentially reducing interstitial fluid pressure and improving the extravasation of
small molecule-based chemotherapeutics. Here we show that pretreatment of human ovarian carcinoma
tumors with sub-optimal doses of the VEGFR targeting tyrosine kinase inhibitor axitinib, but not the EGFR
targeting kinase inhibitor erlotinib, induces a transient period of increased tumor oxygenation.
Doxorubicin administered within this window was found to enter the extravascular tumor space more
rapidly compared to doxorubicin when applied alone or outside this time window. Treatment with the
chemotherapeutics, doxorubicin and RAPTA-C, as well as applying photodynamic therapy during this
period of elevated oxygenation led to enhanced tumor growth inhibition. Improvement of therapy was not
observed when applied outside the window of increased oxygenation. Taken together, these findings further
confirm the hypothesis of angiostasis-induced vascular normalization and also help to understand the
interactions between anti-angiogenesis and other anti-cancer strategies.