Project description:The tumor microenvironment (TME) plays a crucial role in cancer progression and represents an appealing target for cancer treatment. Tumor-associated macrophages (TAMs) are an abundant stromal cell type in the TME and, due to their plasticity, TAMs can be exploited to promote a pro-tumoral response. TAMs have been implicated in facilitating a variety of pro-tumoral pathways including resistance to anti-cancer therapeutics, immune suppression, angiogenesis, and metastasis. However, pan-TAM depleting approaches have not delivered robust clinical outcomes as single agents. This might be explained due to their non-selective targeting of both pro- and anti-tumoral macrophage subsets. As such, therapeutically targeting key pro-tumoral TAM subsets may be a more desirable and efficacious strategy. Our group has recently characterised a subpopulation of pro-angiogenic and immune-suppressive TAMs which can be identified by their expression of the lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1). LYVE-1+ TAMs reside spatially proximal to blood vasculature and adopt a collaborative multi-cellular ‘nest’ arrangement which supports their biological activity. LYVE-1+ TAMs selectively express high levels of the immunomodulatory enzyme heme oxygenase-1 (HO-1), an enzyme which catabolizes heme to generate the biologically active catabolites carbon monoxide (CO), biliverdin and ferrous iron. Genetic inactivation of HO-1 in LYVE-1+ TAMs improve anti-tumor CD8+ T-cell infiltration into the TME and enhances the immune-stimulating effects of chemotherapy, resulting in sustain control of tumor growth in a spontaneous MMTV-PyMT murine model of breast cancer. This highlights that HO-1 represents a key effector pathway of these cells that prevents immune-elimination of tumors. Considering translation of these observations, unfortunately, current HO-1 inhibitors are not orally bioavailable, which limits their utility for chronic diseases, such as cancer, where daily administration would be required. In response to this hurdle, we developed a next generation HO-1 inhibitor called KCL-HO-1i. We demonstrate in pharmacokinetic studies that KCL-HO-1i is orally bioavailable in murine models with a serum half-life of around 3hours. Furthermore, oral delivery of KCL-HO-1i alongside standard of care chemotherapy delivers durable tumor control in MMTV-PyMT mice. We have characterised the response of the TME to KCL-HO-1i using flow cytometry, immunofluorescence and RNA sequencing approaches and demonstrate that KCL-HO-1i targeting perivascular LYVE-1+ TAM function supports a broader switch from an immunological ‘cold’ to ‘hot’ TME which provides a more favourable immune landscape for improving the response to chemotherapeutic drugs. Taken together, our data support the use of KCL-HO-1i as novel immunotherapeutic for targeting the function of perivascular TAMs in cancer.

Project description:Thoracic perivascular adipose tissue (PVAT) is a unique adipose depot that likely influences vascular function and susceptibility to pathogenesis in obesity and metabolic syndrome. Surprisingly, PVAT has been reported to share characteristics of both brown and white adipose, but a detailed direct comparison to interscapular brown adipose tissue (BAT) has not been performed. Here we show by full genome DNA microarray analysis that global gene expression profiles of PVAT are virtually identical to BAT, with equally high expression of Ucp-1, Cidea and other genes known to be uniquely or very highly expressed in BAT. PVAT and BAT also displayed nearly identical phenotypes upon immunohistochemical analysis, and electron microscopy confirmed that PVAT contained multilocular lipid droplets and abundant mitochondria. Compared to white adipose tissue (WAT), PVAT and BAT from C57BL/6 mice fed a high fat diet for 13 weeks had markedly lower expression of immune cell-enriched mRNAs, suggesting resistance to obesity-induced inflammation. Indeed, staining of BAT and PVAT for macrophage markers (F4/80, CD68) in obese mice showed virtually no macrophage infiltration, and FACS analysis of BAT confirmed the presence of very few CD11b+/CD11c+ macrophages in BAT (1.0%) in comparison to WAT (31%). In summary, murine PVAT from the thoracic aorta is virtually identical to interscapular BAT, is resistant to diet-induced macrophage infiltration, and thus may play an important role in protecting the vascular bed from thermal and inflammatory stress. 8-week-old male C57BL6/J mice were fed a normal (ND) or high fat diet (HFD) (Research Diets 12451, 45 kcal% fat) for 13 weeks. Mice were then euthanized and four different adipose depots were harvested for RNA analysis: perivascular fat from the lesser curvature of the aortic arch (PVAT), interscapular brown adipose (BAT), inguinal adipose tissue (SAT), and epididymal adipose tissue (VAT). 250 ng total RNA pooled from two mice was used for cDNA synthesis; 3 biological replicates per tissue and diet were performed for a total of 24 hybridizations.

Project description:INTRODUCTION: Amphiphilic copolymer nanoparticle-encapsulated multi-target chemotherapeutic drugs have attracted considerable attention due to their favorable drug efficiency and potential application prospect. Studies have shown that an amphiphilic copolymer, methoxypoly(ethylene glycol)-poly(lactide-co-glycolide) modified with e-polylysine, and encapsulated with hydrophilic doxorubicin, hydrophobic paclitaxel and survivin siRNA profoundly improved the therapeutic effect both in vitro and in vivo.</br>OBJECTIVES: To investigate how MCF-7 cells would response to the exposure of these nanoparticles over with time and assess the biological effects of these nanoparticles and their encapsulated drugs in a holistic manner.</br>METHODS: MCF-7 cells were treated with PBS, nanocarrier and three encapsulated drugs, respectively. Metabolic alterations associated with nano-drugs exposure were investigated by performing untargeted NMR metabolomics with combination of targeted fatty acids analysis by GC-MS on cell extracts. Altered metabolic pathways were further validated by qRT-PCR approach.</br>RESULTS: Copolymers showed great biocompatibility with cells as it induced transit metabolic disruptions without affecting cell survival rate. The rapid release of encapsulated doxorubicin resulted in inhibition of glycolysis and DNA synthesis, active proteolysis; these metabolic alternations were recovered after 10 h exposure. However, the combination use of multiple drugs consistently induced cell cycle arrest and apoptosis evidenced by reduction in glycolysis, active proteolysis, stimulated O-GlcNAcylation, reduced the PC:GPC ratio and fatty acids accumulation. Prolonged exposure to encapsulated-multiple-drugs also induced oxidative stress to cells.</br>CONCLUSION: These findings provide important insight into the biological effects of nanoparticles and their encapsulated drugs while demonstrate that metabolomics is a powerful approach to evaluate the biological effects of nano-drugs.

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Therapeutically targeting perivascular macrophage effector function improves CD8+ T-cell infiltration and response to chemotherapeutic drugs in cancer

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