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Angiotensin inhibition enhances drug delivery and potentiates chemotherapy by decompressing tumour blood vessels

TL;DR: In this paper, the angiotensin inhibitor losartan reduces stromal collagen and hyaluronan production, associated with decreased expression of profibrotic signals TGF-β1, CCN2 and ET-1.
Abstract: Cancer and stromal cells actively exert physical forces (solid stress) to compress tumour blood vessels, thus reducing vascular perfusion. Tumour interstitial matrix also contributes to solid stress, with hyaluronan implicated as the primary matrix molecule responsible for vessel compression because of its swelling behaviour. Here we show, unexpectedly, that hyaluronan compresses vessels only in collagen-rich tumours, suggesting that collagen and hyaluronan together are critical targets for decompressing tumour vessels. We demonstrate that the angiotensin inhibitor losartan reduces stromal collagen and hyaluronan production, associated with decreased expression of profibrotic signals TGF-β1, CCN2 and ET-1, downstream of angiotensin-II-receptor-1 inhibition. Consequently, losartan reduces solid stress in tumours resulting in increased vascular perfusion. Through this physical mechanism, losartan improves drug and oxygen delivery to tumours, thereby potentiating chemotherapy and reducing hypoxia in breast and pancreatic cancer models. Thus, angiotensin inhibitors —inexpensive drugs with decades of safe use — could be rapidly repurposed as cancer therapeutics.
Citations
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Journal ArticleDOI
TL;DR: This Consensus Statement issues a call to action for all cancer researchers to standardize assays and report metadata in studies of cancer-associated fibroblasts to advance the understanding of this important cell type in the tumour microenvironment.
Abstract: Cancer-associated fibroblasts (CAFs) are a key component of the tumour microenvironment with diverse functions, including matrix deposition and remodelling, extensive reciprocal signalling interactions with cancer cells and crosstalk with infiltrating leukocytes. As such, they are a potential target for optimizing therapeutic strategies against cancer. However, many challenges are present in ongoing attempts to modulate CAFs for therapeutic benefit. These include limitations in our understanding of the origin of CAFs and heterogeneity in CAF function, with it being desirable to retain some antitumorigenic functions. On the basis of a meeting of experts in the field of CAF biology, we summarize in this Consensus Statement our current knowledge and present a framework for advancing our understanding of this critical cell type within the tumour microenvironment.

1,616 citations

Journal ArticleDOI
TL;DR: How recent developments in drug delivery could enable new cancer immunotherapies and improve on existing ones are discussed, and the current delivery obstacles are examined.
Abstract: Immunotherapy has become a powerful clinical strategy for treating cancer. The number of immunotherapy drug approvals has been increasing, with numerous treatments in clinical and preclinical development. However, a key challenge in the broad implementation of immunotherapies for cancer remains the controlled modulation of the immune system, as these therapeutics have serious adverse effects including autoimmunity and nonspecific inflammation. Understanding how to increase the response rates to various classes of immunotherapy is key to improving efficacy and controlling these adverse effects. Advanced biomaterials and drug delivery systems, such as nanoparticles and the use of T cells to deliver therapies, could effectively harness immunotherapies and improve their potency while reducing toxic side effects. Here, we discuss these research advances, as well as the opportunities and challenges for integrating delivery technologies into cancer immunotherapy, and we critically analyse the outlook for these emerging areas.

1,295 citations

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TL;DR: In this paper, the authors summarize lessons learned from preclinical and clinical studies over the past decade and propose strategies for improving antiangiogenic therapy outcomes for malignant and nonmalignant diseases.

1,093 citations

Journal ArticleDOI
TL;DR: The roles of VEGF and ANG2 are outlined, and ways that antiangiogenic agents can be combined with immune-checkpoint inhibitors to potentially improve patient outcomes are suggested, and avenues of future research are highlighted.
Abstract: Immunotherapy has emerged as a major therapeutic modality in oncology. Currently, however, the majority of patients with cancer do not derive benefit from these treatments. Vascular abnormalities are a hallmark of most solid tumours and facilitate immune evasion. These abnormalities stem from elevated levels of proangiogenic factors, such as VEGF and angiopoietin 2 (ANG2); judicious use of drugs targeting these molecules can improve therapeutic responsiveness, partially owing to normalization of the abnormal tumour vasculature that can, in turn, increase the infiltration of immune effector cells into tumours and convert the intrinsically immunosuppressive tumour microenvironment (TME) to an immunosupportive one. Immunotherapy relies on the accumulation and activity of immune effector cells within the TME, and immune responses and vascular normalization seem to be reciprocally regulated. Thus, combining antiangiogenic therapies and immunotherapies might increase the effectiveness of immunotherapy and diminish the risk of immune-related adverse effects. In this Perspective, we outline the roles of VEGF and ANG2 in tumour immune evasion and progression, and discuss the evidence indicating that antiangiogenic agents can normalize the TME. We also suggest ways that antiangiogenic agents can be combined with immune-checkpoint inhibitors to potentially improve patient outcomes, and highlight avenues of future research.

1,031 citations

Journal ArticleDOI
TL;DR: A new population of CAFs that express MHC class II and CD74, but do not express classical co-stimulatory molecules are described, and it is found that they activate CD4+ T cells in an antigen-specific fashion in a model system, confirming their putative immune-modulatory capacity.
Abstract: Cancer-associated fibroblasts (CAF) are major players in the progression and drug resistance of pancreatic ductal adenocarcinoma (PDAC). CAFs constitute a diverse cell population consisting of several recently described subtypes, although the extent of CAF heterogeneity has remained undefined. Here we use single-cell RNA sequencing to thoroughly characterize the neoplastic and tumor microenvironment content of human and mouse PDAC tumors. We corroborate the presence of myofibroblastic CAFs and inflammatory CAFs and define their unique gene signatures in vivo. Moreover, we describe a new population of CAFs that express MHC class II and CD74, but do not express classic costimulatory molecules. We term this cell population "antigen-presenting CAFs" and find that they activate CD4+ T cells in an antigen-specific fashion in a model system, confirming their putative immune-modulatory capacity. Our cross-species analysis paves the way for investigating distinct functions of CAF subtypes in PDAC immunity and progression. SIGNIFICANCE: Appreciating the full spectrum of fibroblast heterogeneity in pancreatic ductal adenocarcinoma is crucial to developing therapies that specifically target tumor-promoting CAFs. This work identifies MHC class II-expressing CAFs with a capacity to present antigens to CD4+ T cells, and potentially to modulate the immune response in pancreatic tumors.See related commentary by Belle and DeNardo, p. 1001.This article is highlighted in the In This Issue feature, p. 983.

900 citations

References
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Journal ArticleDOI
12 Jun 2009-Science
TL;DR: Studying a mouse model of PDA that is refractory to the clinically used drug gemcitabine, it is found that the tumors in this model were poorly perfused and poorly vascularized, properties that are shared with human PDA.
Abstract: Pancreatic ductal adenocarcinoma (PDA) is among the most lethal human cancers in part because it is insensitive to many chemotherapeutic drugs. Studying a mouse model of PDA that is refractory to the clinically used drug gemcitabine, we found that the tumors in this model were poorly perfused and poorly vascularized, properties that are shared with human PDA. We tested whether the delivery and efficacy of gemcitabine in the mice could be improved by coadministration of IPI-926, a drug that depletes tumor-associated stromal tissue by inhibition of the Hedgehog cellular signaling pathway. The combination therapy produced a transient increase in intratumoral vascular density and intratumoral concentration of gemcitabine, leading to transient stabilization of disease. Thus, inefficient drug delivery may be an important contributor to chemoresistance in pancreatic cancer.

2,831 citations

Journal ArticleDOI
TL;DR: It is shown that systemic administration of an enzymatic agent can ablate stromal HA from autochthonous murine PDA, normalize IFP, and re-expand the microvasculature and in combination with the standard chemotherapeutic, gemcitabine, the treatment permanently remodels the tumor microenvironment and consistently achieves objective tumor responses, resulting in a near doubling of overall survival.

1,656 citations

Journal ArticleDOI
07 Apr 2006-Science
TL;DR: Losartan, a drug already in clinical use for hypertension, merits investigation as a therapeutic strategy for patients with Marfan syndrome and has the potential to prevent the major life-threatening manifestation of this disorder.
Abstract: Aortic aneurysm and dissection are manifestations of Marfan syndrome (MFS), a disorder caused by mutations in the gene that encodes fibrillin-1. Selected manifestations of MFS reflect excessive signaling by the transforming growth factor–β (TGF-β) family of cytokines. We show that aortic aneurysm in a mouse model of MFS is associated with increased TGF-β signaling and can be prevented by TGF-β antagonists such as TGF-β–neutralizing antibody or the angiotensin II type 1 receptor (AT1) blocker, losartan. AT1 antagonism also partially reversed noncardiovascular manifestations of MFS, including impaired alveolar septation. These data suggest that losartan, a drug already in clinical use for hypertension, merits investigation as a therapeutic strategy for patients with MFS and has the potential to prevent the major life-threatening manifestation of this disorder.

1,620 citations

Journal ArticleDOI
TL;DR: The first combined, high-resolution measurements of interstitial pH and pO2 profiles between adjacent vessels in a human tumor xenograft are reported, using fluorescence ratio imaging and phosphorescence quenching microscopy.
Abstract: The partial pressure of oxygen (pO2) and pH play critical roles in tumor biology and therapy. We report here the first combined, high-resolution (≤10 μm) measurements of interstitial pH and pO2 profiles between adjacent vessels in a human tumor xenograft, using fluorescence ratio imaging and phosphorescence quenching microscopy. We found (1) heterogeneity in shapes of pH and pO2 profiles; (2) a discordant relation between local pH profiles and corresponding pO2 profiles, yet a strong correlation between mean pH and pO2 profiles; (3) no correlation between perivascular pH/pO2 and nearest vessel blood flow; and (4) well-perfused tumor vessels that were hypoxic and, consequently, large hypoxic areas in the surrounding interstitium. Such multiparameter measurements of the in vivo microenvironment provide unique insights into biological processes in tumors and their response to treatment.

1,579 citations

Journal ArticleDOI
TL;DR: Blockade of pathways mediating macrophage recruitment, in combination with chemotherapy, significantly decreases primary tumor progression, reduces metastasis, and improves survival by CD8+ T-cell-dependent mechanisms, thus indicating that the immune microenvironment of tumors can be reprogrammed to instead foster antitumor immunity and improve response to cytotoxic therapy.
Abstract: Immune-regulated pathways influence multiple aspects of cancer development. In this article we demonstrate that both macrophage abundance and T-cell abundance in breast cancer represent prognostic indicators for recurrence-free and overall survival. We provide evidence that response to chemotherapy is in part regulated by these leukocytes; cytotoxic therapies induce mammary epithelial cells to produce monocyte/macrophage recruitment factors, including colony stimulating factor 1 (CSF1) and interleukin-34, which together enhance CSF1 receptor (CSF1R)–dependent macrophage infiltration. Blockade of macrophage recruitment with CSF1R-signaling antagonists, in combination with paclitaxel, improved survival of mammary tumor–bearing mice by slowing primary tumor development and reducing pulmonary metastasis. These improved aspects of mammary carcinogenesis were accompanied by decreased vessel density and appearance of antitumor immune programs fostering tumor suppression in a CD8 + T-cell–dependent manner. These data provide a rationale for targeting macrophage recruitment/response pathways, notably CSF1R, in combination with cytotoxic therapy, and identification of a breast cancer population likely to benefit from this novel therapeutic approach. Significance: These findings reveal that response to chemotherapy is in part regulated by the tumor immune microenvironment and that common cytotoxic drugs induce neoplastic cells to produce monocyte/macrophage recruitment factors, which in turn enhance macrophage infiltration into mammary adenocarcinomas. Blockade of pathways mediating macrophage recruitment, in combination with chemotherapy, significantly decreases primary tumor progression, reduces metastasis, and improves survival by CD8 + T-cell–dependent mechanisms, thus indicating that the immune microenvironment of tumors can be reprogrammed to instead foster antitumor immunity and improve response to cytotoxic therapy. Cancer Discovery; 1(1); 54–67. ©2011 AACR . This article is highlighted in the In This Issue feature, p. 4

1,520 citations

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