With the emergence of the tumor microenvironment as an essential ingredient of cancer malignancy, therapies targeting the host compartment of tumors have begun to be designed and applied in the ...clinic.
The malignant features of cancer cells cannot be manifested without an important interplay between cancer cells and their local environment. The tumor infiltrate composed of immune cells, angiogenic vascular cells, lymphatic endothelial cells, and cancer-associated fibroblastic cells contributes actively to cancer progression. The ability to change these surroundings is an important property by which tumor cells are able to acquire some of the hallmark functions necessary for tumor growth and metastatic dissemination. Thus in the clinical setting the targeting of the tumor microenvironment to encapsulate or destroy cancer cells in their local environment has become mandatory. The variety of stromal cells, the complexity of the molecular components of the tumor stroma, and the similarity with normal tissue present huge challenges for therapies targeting the tumor microenvironment. These issues and their interplay are addressed in this review. After a decade of intensive clinical trials targeting cellular components of the tumor microenvironment, more recent investigations have shed light on the important role in cancer progression played by the noncellular stromal compartment composed of the extracellular matrix.
A better understanding of how the tumor environment affects cancer progression should provide new targets for the isolation and destruction of cancer cells via interference with the complex crosstalk established between cancer cells, host cells, and their surrounding extracellular matrix.
Blood and lymphatic systems work in close collaboration to ensure their respective physiological functions. The lymphatic vessel network is being extensively studied, but has been overlooked as ...compared to the blood vasculature mainly due to the problematic discrimination of lymphatic vessels from the blood ones. This issue has been fortunately resolved in the past decade leading to the emergence of a huge amount of data in lymphatic biology revealing many shared features with the blood vasculature. However, this likeliness between the two vascular systems may lead to a simplistic view of lymphatics and a direct transcription of what is known for the blood system to the lymphatic one, thereby neglecting the lymphatic specificities. In this context, this review aims to clarify the main differences between the two vascular systems focusing on recently discovered lymphatic features.
Tumor recurrence is a major clinical issue that represents the principal cause of cancer-related deaths, with few targetable common pathways. Mechanisms by which residual tumors persist and progress ...under a continuous shift between hypoxia-reoxygenation after neoadjuvent-therapy are unknown. In this study, we investigated the role of lipid metabolism and tumor redox balance in tumor recurrence.
Lipidomics, proteomics and mass spectrometry imaging approaches where applied to mouse tumor models of recurrence. Genetic and pharmacological inhibitions of lipid mediators in tumors were used in vivo and in functional assays in vitro.
We found that stearoyl-CoA desaturase-1 (SCD1) expressed by cancer cells and fatty acid binding protein-4 (FABP4) produced by tumor endothelial cells (TECs) and adipocytes in the tumor microenvironment (TME) are essential for tumor relapse in response to tyrosine kinase inhibitors (TKI) and chemotherapy. SCD1 and FABP4 were also found upregulated in recurrent human breast cancer samples and correlated with worse prognosis of cancer patients with different types of tumors. Mechanistically, SCD1 leads to fatty acid (FA) desaturation and FABP4 derived from TEM enhances lipid droplet (LD) in cancer cells, which cooperatively protect from oxidative stress-induced ferroptosis. We revealed that lipid mobilization and desaturation elicit tumor intrinsic antioxidant and anti-ferroptotic resources for survival and regrowth in a harsh TME. Inhibition of lipid transport from TME by FABP4 inhibitor reduced tumor regrowth and by genetic — or by pharmacological — targeting SCD1 in vivo, tumor regrowth was abolished completely.
This finding unveils that it is worth taking advantage of tumor lipid addiction, as a tumor vulnerability to design novel treatment strategy to prevent cancer recurrence.
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•Increased oxidative stress markers and lipid metabolism in residual tumors.•Expression of SCD1 in cancer cells and FABP4 in the tumor microenvironment drive tumor recurrence.•Fatty acid desaturation by SCD1 and lipid transport by FABP4 confer resistance to ROS and ferroptosis.•Blocking SCD1 and FABP4 sensitized cancer cells to ROS-induced ferroptosis and reduced tumor recurrence.
Objective
To compare the gene expression patterns of synovial cells from inflamed or normal/reactive areas of synovial membrane obtained from the same patient with osteoarthritis (OA).
Methods
At the ...time of total knee replacement, synovial tissues were obtained from 12 patients with knee OA. The inflammation status of the synovial membrane was characterized according to macroscopic criteria and classified as normal/reactive or inflamed. Biopsy samples were cultured separately for 7 days. Microarray gene expression profiling was performed on normal/reactive and inflamed areas. Western blot and immunohistochemistry were used to confirm the identified genes that were differentially expressed.
Results
We identified 896 genes that were differentially expressed between normal/reactive and inflamed areas. The key pathways were related to inflammation, cartilage metabolism, Wnt signaling, and angiogenesis. In the inflammation network, the genes TREM1 and S100A9 were strongly up‐regulated. The genes MMP3, MMP9, CTSH (cathepsin H), and CTSS (cathepsin S) were significantly up‐regulated in the cartilage catabolism pathway, while the most up‐regulated anabolism enzyme gene was HAS1. In the Wnt signaling pathway, the genes for Wnt‐5a and low‐density lipoprotein receptor–related protein 5 were up‐regulated, while the gene FZD2 and the gene for Dkk‐3 were down‐regulated. Finally, STC1, which codes for a protein involved in angiogenesis, was identified as the most up‐regulated gene in inflamed compared with normal/reactive areas.
Conclusion
This study is the first to identify different expression patterns between 2 areas of the synovial membrane from the same patient. These differences concern several key pathways involved in OA pathogenesis. This analysis also provides information regarding new genes and proteins as potential targets of treatment.
The mouse model of laser-induced choroidal neovascularization (CNV) has been used extensively in studies of the exudative form of age-related macular degeneration (AMD). This experimental in vivo ...model relies on laser injury to perforate Bruch's membrane, resulting in subretinal blood vessel recruitment from the choroid. By recapitulating the main features of the exudative form of human AMD, this assay has served as the backbone for testing antiangiogenic therapies. This standardized protocol can be applied to transgenic mice and can include treatments with drugs, recombinant proteins, antibodies, adenoviruses and pre-microRNAs to aid in the search for new molecular regulators and the identification of novel targets for innovative treatments. This robust assay requires 7-14 d to complete, depending on the treatment applied and whether immunostaining is performed. This protocol includes details of how to induce CNV, including laser induction, lesion excision, processing and different approaches to quantify neoformed vasculature.
Lymphatic vessels are lined by lymphatic endothelial cells (LECs), and are critical for health. However, the role of metabolism in lymphatic development has not yet been elucidated. Here we report ...that in transgenic mouse models, LEC-specific loss of CPT1A, a rate-controlling enzyme in fatty acid β-oxidation, impairs lymphatic development. LECs use fatty acid β-oxidation to proliferate and for epigenetic regulation of lymphatic marker expression during LEC differentiation. Mechanistically, the transcription factor PROX1 upregulates CPT1A expression, which increases acetyl coenzyme A production dependent on fatty acid β-oxidation. Acetyl coenzyme A is used by the histone acetyltransferase p300 to acetylate histones at lymphangiogenic genes. PROX1-p300 interaction facilitates preferential histone acetylation at PROX1-target genes. Through this metabolism-dependent mechanism, PROX1 mediates epigenetic changes that promote lymphangiogenesis. Notably, blockade of CPT1 enzymes inhibits injury-induced lymphangiogenesis, and replenishing acetyl coenzyme A by supplementing acetate rescues this process in vivo.
The only documented activity of a subclass of ADAMTS proteases comprising ADAMTS2, 3 and 14 is the cleavage of the aminopropeptide of fibrillar procollagens. A limited number of in vitro studies ...suggested that ADAMTS3 is mainly responsible for procollagen II processing in cartilage. Here, we created an ADAMTS3 knockout mouse (Adamts3
−/−
) model to determine in vivo the actual functions of ADAMTS3. Heterozygous Adamts3
+/−
mice were viable and fertile, but their intercrosses demonstrated lethality of Adamts3
−/−
embryos after 15 days of gestation. Procollagens I, II and III processing was unaffected in these embryos. However, a massive lymphedema caused by the lack of lymphatics development, an abnormal blood vessel structure in the placenta and a progressive liver destruction were observed. These phenotypes are most probably linked to dysregulation of the VEGF-C pathways. This study is the first demonstration that an aminoprocollagen peptidase is crucial for developmental processes independently of its primary role in collagen biology and has physiological functions potentially involved in several human diseases related to angiogenesis and lymphangiogenesis.
Solid tumors are composed of tumor cells and stromal cells including lymphatic endothelial cells (LEC), which are mainly viewed as cells forming lymphatic vessels involved in the transport of ...metastatic and immune cells. We here reveal a new mechanism by which tumor exposed-LEC (teLEC) exert mitogenic effects on tumor cells. Our conclusions are supported by morphological and molecular changes induced in teLEC that in turn enhance cancer cell invasion in 3D cultures and tumor cell proliferation in vivo. The characterization of teLEC secretome by RNA-Sequencing and cytokine array revealed that interleukine-6 (IL6) is one of the most modulated molecules in teLEC, whose production was negligible in unexposed LEC. Notably, neutralizing anti-human IL6 antibody abrogated teLEC-mediated mitogenic effects in vivo, when LEC were mixed with tumor cells in the ear sponge assay. We here assign a novel function to teLEC that is beyond their role of lymphatic vessel formation. This work highlights a new paradigm, in which teLEC exert “fibroblast-like properties”, contribute in a paracrine manner to the control of tumor cell properties and are worth considering as key stromal determinant in future studies.
•teLEC, but not normal LEC, produce huge amount of IL6.•IL6-derived teLEC exert mitogenic effect on tumor cells, in the primary tumor.•teLEC act as fibroblast-like cells in the tumor microenvironment.•It warrants to revisit the “vascular-centric view” of LECs.
The endothelial cell spheroid assay provides a suitable in vitro model to study (lymph) angiogenesis and test pro- and anti-(lymph) angiogenic factors or drugs. Usually, the extent of cell invasion, ...observed through optical microscopy, is measured. The present study proposes the spatial distribution of migrated cells as a new descriptor of the (lymph) angiogenic response. The utility of this novel method rests with its capacity to locally characterise spheroid structure, allowing not only the investigation of single and collective cell invasion but also the evolution of the spheroid core itself. Moreover, the proposed method can be applied to 2D-projected spheroid images obtained by optical microscopy, as well as to 3D images acquired by confocal microscopy. To validate the proposed methodology, endothelial cell invasion was evaluated under different experimental conditions. The results were compared with widely used global parameters. The comparison shows that our method prevents local spheroid modifications from being overlooked and leading to the possible misinterpretation of results.
Estetrol (E4) is a natural estrogen with promising therapeutic applications in humans. The European Medicines Agency and the Food and Drug Administration have approved the use of 15 mg E4/3 mg ...drospirenone for contraceptive indication. Phase III clinical trials with 15-20 mg E4 for the relief of climacteric complaints are currently running. Relevant data from preclinical animal models are needed to characterize the molecular mechanisms and the pharmacological effects of E4 and possibly to reveal new therapeutic applications and to anticipate potential adverse effects. Therefore, it is important to design experimental procedures in rodents that closely mimic or anticipate human E4 exposure. In this study, we compared the effects of E4 exposure after acute or chronic administration in women and mice. Women who received chronic E4 treatment per os at a dose of 15 mg once daily reached a steady state within 6 to 8 days, with a mean plasma concentration of 3.20 ng/mL. Importantly, with subcutaneous, intraperitoneal or oral administration of E4 in mice, a stable concentration over time that would mimic human pharmacokinetics could not be achieved. The use of osmotic minipumps continuously releasing E4 for several weeks provided an exposure profile mimicking chronic oral administration in women. Measurements of the circulating concentration of E4 in mice revealed that the mouse equivalent dose necessary to mimic human treatment does not fit with the allometric prediction. In conclusion, this study highlights the importance of precise definition of the most appropriate dose and route of administration to utilize when developing predictive preclinical animal models to mimic or anticipate specific human treatment.
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