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Cancer health disparities among populations are the result of a combination of socioeconomic, environmental, behavioral, and biological factors, which affect cancer incidence, prevalence, mortality, survivorship, financial burden, and screening rates. The long-standing Meharry Medical College (MMC), Vanderbilt-Ingram Cancer Center (VICC), Tennessee State University (TSU) Cancer Partnership has built an exceptional cancer research and training environment to support the efforts of diverse investigators in addressing disparities. Over the past 20 years, collaborative partnership efforts across multiple disciplines have supported research into the determinants of cancer health disparities at a National Cancer Institute-designated comprehensive cancer center (VICC) along with enhancing research infrastructure and training at MMC and TSU, two institutions that serve predominantly underserved populations and underrepresented students. Moreover, the geographical placement of this partnership in Tennessee, a region with some of the highest cancer incidence and mortality in the United States, has provided an especially important opportunity to positively affect outcomes for cancer patients.

Objective: Pancreatic ductal adenocarcinoma (PDAC) is the deadliest cancer. Cancer-associated thrombosis/thromboembolism (CAT), frequently observed in PDAC, is known as a poor prognostic factor. Here, we investigated the underlying mechanisms between PDAC and CAT, and performed a trial of therapeutic approach for PDAC using a genetically engineered mouse model, PKF ( Ptf1a cre/+ ;LSL-Kras G12D/+ ;Tgfbr2 flox/flox )., Design: Presence of CAT in PKF mice was detected by systemic autopsy. Plasma cytokines were screened by cytokine antibody array. Murine and human plasma atrial natriuretic peptide (ANP) and soluble vascular cell adhesion molecule 1 (sVCAM-1) were determined by ELISA. Distribution of VCAM-1 in PKF mice and human autopsy samples was detected by immunohistochemistry. PKF mice were treated with anti-VCAM-1 antibody and the effects on survival, distribution of CAT and the tumour histology were analysed., Results: We found spontaneous CAT with cardiomegaly in 68.4% PKF mice. Increase of plasma ANP and sVCAM-1 was observed in PKF mice and PDAC patients with CAT. VCAM-1 was detected in the activated endothelium and thrombi. Administration of anti-VCAM-1 antibody to PKF mice inhibited tumour growth, neutrophil/macrophage infiltration, tumour angiogenesis and progression of CAT; moreover, it dramatically extended survival (from 61 to 253 days, p<0.01)., Conclusion: Blocking VCAM-1/sVCAM-1 might be a potent therapeutic approach for PDAC as well as CAT, which can contribute to the prognosis. Increase of plasma ANP and sVCAM-1 might be a diagnostic approach for CAT in PDAC., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Pancreatic cancer is one of the malignant diseases with the worst prognosis. Resistance to chemotherapy is a major difficulty in treating the disease. We analyzed plasma samples from a genetically engineered mouse model of pancreatic cancer and found soluble vascular cell adhesion molecule-1 (sVCAM-1) increases in response to gemcitabine treatment. VCAM-1 was expressed and secreted by murine and human pancreatic cancer cells. Subcutaneous allograft tumors with overexpression or knock-down of VCAM-1, as well as VCAM-1-blocking treatment in the spontaneous mouse model of pancreatic cancer, revealed that sVCAM-1 promotes tumor growth and resistance to gemcitabine treatment in vivo but not in vitro. By analyzing allograft tumors and co-culture experiments, we found macrophages were attracted by sVCAM-1 to the tumor microenvironment and facilitated resistance to gemcitabine in tumor cells. In a clinical setting, we found that the change of sVCAM-1 in the plasma of patients with advanced pancreatic cancer was an independent prognostic factor for gemcitabine treatment. Collectively, gemcitabine treatment increases the release of sVCAM-1 from pancreatic cancer cells, which attracts macrophages into the tumor, thereby promoting the resistance to gemcitabine treatment. sVCAM-1 may be a potent clinical biomarker and a potential target for the therapy in pancreatic cancer.

Increased transforming growth factor-β (TGF-β) signaling contributes to the pathophysiology of aortic aneurysm in Marfan syndrome (MFS). Recent reports indicate that a small but significant number of inflammatory cells are infiltrated into the aortic media and adventitia in MFS. However, little is known about the contribution of myeloid cells to aortic aneurysmal formation. In this study, we ablated the TGF-β type II receptor gene Tgfbr2 in myeloid cells of Fbn1C1039G/+ MFS mice (Fbn1C1039G/+;LysM-Cre/+;Tgfbr2fl/fl mice, hereinafter called Fbn1C1039G/+;Tgfbr2MyeKO) and evaluated macrophage infiltration and TGF-β signaling in the aorta. Aneurysmal formation with fragmentation and disarray of medial elastic fibers observed in MFS mice was significantly ameliorated in Fbn1C1039G/+;Tgfbr2MyeKO mice. In the aorta of Fbn1C1039G/+;Tgfbr2MyeKO mice, both canonical and noncanonical TGF-β signals were attenuated and the number of infiltrated F4/80-positive macrophages was significantly reduced. In vitro, TGF-β enhanced the migration capacity of RAW264.7 macrophages. These findings suggest that TGF-β signaling in myeloid cells promotes aortic aneurysmal formation and its inhibition might be a novel therapeutic target in MFS., Competing Interests: The authors have declared that no competing interests exist.

TGFβ plays a crucial role in the tumor microenvironment by regulating cell-cell and cell-stroma interactions. We previously demonstrated that TGFβ signaling on myeloid cells regulates expression of CD73, a key enzyme for production of adenosine, a protumorigenic metabolite implicated in regulation of tumor cell behaviors, immune response, and angiogenesis. Here, using an MMTV-PyMT mouse mammary tumor model, we discovered that deletion of TGFβ signaling on myeloid cells (PyMT/TGFβRII LysM ) affects extracellular matrix (ECM) formation in tumor tissue, specifically increasing collagen and decreasing fibronectin deposition. These changes were associated with mitigated tumor growth and reduced metastases. Reduced TGFβ signaling on fibroblasts was associated with their proximity to CD73 + myeloid cells in tumor tissue. Consistent with these findings, adenosine significantly downregulated TGFβ signaling on fibroblasts, an effect regulated by A 2A and A 2B adenosine receptors. METABRIC dataset analysis revealed that patients with triple-negative breast cancer and basal type harbored a similar signature of adenosine and ECM profiles; high expression of A 2B adenosine receptors correlated with decreased expression of Col1 and was associated with poor outcome. Taken together, our studies reveal a new role for TGFβ signaling on myeloid cells in tumorigenesis. This discovered cross-talk between TGFβ/CD73 on myeloid cells and TGFβ signaling on fibroblasts can contribute to ECM remodeling and protumorigenic actions of cancer-associated fibroblasts. SIGNIFICANCE: TGFβ signaling on fibroblasts is decreased in breast cancer, correlates with poor prognosis, and appears to be driven by adenosine that accelerates tumor progression and metastasis via ECM remodeling., (©2020 American Association for Cancer Research.)

A number of important drugs used to treat cancer-many of which serve as the backbone of modern chemotherapy regimens-have outdated prescribing information in their drug labeling. The Food and Drug Administration is undertaking a pilot project to develop a process and criteria for updating prescribing information for longstanding oncology drugs, based on the breadth of knowledge the cancer community has accumulated with the use of these drugs over time. This article highlights a number of considerations for labeling updates, including selecting priorities for updating; data sources and evidentiary criteria; as well as the risks, challenges, and opportunities for iterative review to ensure prescribing information for oncology drugs remains relevant to current clinical practice., (© 2019 The Authors. The Oncologist published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.)

Pancreatic ductal adenocarcinoma (PDAC) is characterized by dense stromal reaction (desmoplasia). We have previously reported that mice with conditional Kras G12D mutation and knockout of TGF-β receptor type II (Tgfbr2), PKF mice, develop PDAC with desmoplasia modulated by CXC chemokines that are produced by PDAC cells through tumor-stromal interaction. In this study, we further discovered that PDAC and cancer-associated fibroblast (CAF) accelerated each other's invasion and migration through the CXC chemokines-receptor (CXCLs-CXCR2) axis. Heterozygous knockout of Cxcr2 in PKF mice (PKF2h mice) prolonged survival and inhibited both tumor angiogenesis and PDAC microinvasion. Infiltration of neutrophils, myeloid-derived suppressor cells (MDSCs), and arginase-1 + M2-like tumor-associated macrophages (TAMs) significantly decreased in the tumors of PKF2h mice, whereas inducible nitric oxide synthase (iNOS) + M1-like TAMs and apoptotic tumor cells markedly increased, which indicated that blockade of the CXCLs-CXCR2 axis resulted in a shift of immune-inflammatory microenvironment. These results suggest that blocking of the CXCLs-CXCR2 axis in tumor-stromal interactions could be a therapeutic approach against PDAC progression.

Cancer-associated fibroblasts (CAFs) are highly prominent in breast tumors, but their functional heterogeneity and origin are still largely unresolved. We report that bone marrow (BM)-derived mesenchymal stromal cells (MSCs) are recruited to primary breast tumors and to lung metastases and differentiate to a distinct subpopulation of CAFs. We show that BM-derived CAFs are functionally important for tumor growth and enhance angiogenesis via up-regulation of Clusterin. Using newly generated transgenic mice and adoptive BM transplantations, we demonstrate that BM-derived fibroblasts are a substantial source of CAFs in the tumor microenvironment. Unlike resident CAFs, BM-derived CAFs do not express PDGFRα, and their recruitment resulted in a decrease in the percentage of PDGFRα-expressing CAFs. Strikingly, decrease in PDGFRα in breast cancer patients was associated with worse prognosis, suggesting that BM-derived CAFs may have deleterious effects on survival. Therefore, PDGFRα expression distinguishes two functionally unique CAF populations in breast tumors and metastases and may have important implications for patient stratification and precision therapeutics., (© 2018 Raz et al.)

Wilms tumor (WT) is the most common renal malignancy in children and the fourth most common pediatric solid malignancy in the US. Although the mechanisms underlying the WT biology are complex, these tumors most often demonstrate activation of the canonical Wnt/β-catenin pathway. We and others have shown that constitutive activation of β-catenin restricted to the renal epithelium is sufficient to induce primitive renal epithelial tumors, which resemble human WT. Here we demonstrate that pharmacologic inhibition of β-catenin gene transcription with pyrvinium inhibits tumor growth and metastatic progression in a murine model of WT. Cellular invasion is significantly inhibited in both murine WT-like and human WT cells and is accompanied by downregulation of the oncogenes Myc and Birc5 (survivin). Our studies provide proof of the concept that the canonical Wnt/β-catenin pathway may be a novel therapeutic target in the management of WT.

The survival rate for pancreatic ductal adenocarcinoma (PDAC) remains low. More therapeutic options to treat this disease are needed, for the current standard of care is ineffective. Using an animal model of aggressive PDAC (Kras/p48 TGFβRIIKO ), we discovered an effect of TGFβ signaling in regulation of G-CSF secretion in pancreatic epithelium. Elevated concentrations of G-CSF in PDAC promoted differentiation of Ly6G + cells from progenitors, stimulated IL10 secretion from myeloid cells, and decreased T-cell proliferation via upregulation of Arg, iNOS, VEGF, IL6, and IL1b from CD11b + cells. Deletion of csf3 in PDAC cells or use of a G-CSF-blocking antibody decreased tumor growth. Anti-G-CSF treatment in combination with the DNA synthesis inhibitor gemcitabine reduced tumor size, increased the number of infiltrating T cells, and decreased the number of Ly6G + cells more effectively than gemcitabine alone. Human analysis of human datasets from The Cancer Genome Atlas and tissue microarrays correlated with observations from our mouse model experiments, especially in patients with grade 1, stage II disease. We propose that in aggressive PDAC, elevated G-CSF contributes to tumor progression through promoting increases in infiltration of neutrophil-like cells with high immunosuppressive activity. Such a mechanism provides an avenue for a neoadjuvant therapeutic approach for this devastating disease. Cancer Immunol Res; 5(9); 718-29. ©2017 AACR ., (©2017 American Association for Cancer Research.)

Purpose: Metastatic breast cancers continue to elude current therapeutic strategies, including those utilizing PI3K inhibitors. Given the prominent role of PI3Kα,β in tumor growth and PI3Kγ,δ in immune cell function, we sought to determine whether PI3K inhibition altered antitumor immunity. Experimental Design: The effect of PI3K inhibition on tumor growth, metastasis, and antitumor immune response was characterized in mouse models utilizing orthotopic implants of 4T1 or PyMT mammary tumors into syngeneic or PI3Kγ -null mice, and patient-derived breast cancer xenografts in humanized mice. Tumor-infiltrating leukocytes were characterized by IHC and FACS analysis in BKM120 (30 mg/kg, every day) or vehicle-treated mice and PI3Kγ null versus PI3Kγ WT mice. On the basis of the finding that PI3K inhibition resulted in a more inflammatory tumor leukocyte infiltrate, the therapeutic efficacy of BKM120 (30 mg/kg, every day) and anti-PD1 (100 μg, twice weekly) was evaluated in PyMT tumor-bearing mice. Results: Our findings show that PI3K activity facilitates tumor growth and surprisingly restrains tumor immune surveillance. These activities could be partially suppressed by BKM120 or by genetic deletion of PI3Kγ in the host. The antitumor effect of PI3Kγ loss in host, but not tumor, was partially reversed by CD8 + T-cell depletion. Treatment with therapeutic doses of both BKM120 and antibody to PD-1 resulted in consistent inhibition of tumor growth compared with either agent alone. Conclusions: PI3K inhibition slows tumor growth, enhances antitumor immunity, and heightens susceptibility to immune checkpoint inhibitors. We propose that combining PI3K inhibition with anti-PD1 may be a viable therapeutic approach for triple-negative breast cancer. Clin Cancer Res; 23(13); 3371-84. ©2016 AACR ., (©2016 American Association for Cancer Research.)

The cellular and noncellular components surrounding the tumor cells influence many aspects of tumor progression. Transforming growth factor β (TGF-β), bone morphogenetic proteins (BMPs), and activins have been shown to regulate the phenotype and functions of the microenvironment and are attractive targets to attenuate protumorigenic microenvironmental changes. Given the pleiotropic nature of the cytokines involved, a full understanding of their effects on numerous cell types in many contexts is necessary for proper clinical intervention. In this review, we will explore the various effects of TGF-β, BMP, and activin signaling on stromal phenotypes known to associate with cancer progression. We will summarize these findings in the context of their tumor suppressive or promoting effects, as well as the molecular changes that these cytokines induce to influence stromal phenotypes., (Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.)

Wilms tumor (WT) is the most common renal neoplasm of childhood and affects 1 in 10 000 children aged less than 15 years. These embryonal tumors are thought to arise from primitive nephrogenic rests that derive from the metanephric mesenchyme during kidney development and are characterized partly by increased Wnt/β-catenin signaling. We previously showed that coordinate activation of Ras and β-catenin accelerates the growth and metastatic progression of a murine WT model. Here, we show that activating KRAS mutations can be found in human WT. In addition, high levels of phosphorylated AKT are present in the majority of WT. We further show in a mouse model and in renal epithelial cells that Ras cooperates with β-catenin to drive metastatic disease progression and promotes in vitro tumor cell growth, migration, and colony formation in soft agar. Cellular transformation and metastatic disease progression of WT cells are in part dependent on PI3K/AKT activation and are inhibited via pharmacological inhibition of this pathway. Our studies suggest both KRAS mutations and AKT activation are present in WT and may represent novel therapeutic targets for this disease., (© 2017 The Authors. Published by FEBS Press and John Wiley & Sons Ltd.)

The TGF-β pathway plays a major role in tumor progression through regulation of epithelial and stromal cell signaling. Dysfunction of the pathway can lead to carcinoma progression and metastasis. To gain insight into the stromal role of the TGF-β pathway in breast cancer, we performed laser capture microdissection (LCM) from breast cancer patients and reduction mammoplasty patients. Microdissected tumor stroma and normal breast stroma were examined for gene expression. Expression of the TGF-β type III receptor ( TGFBR3 ) was greatly decreased in the tumor stroma compared to control healthy breast tissue. These results demonstrated a 44-fold decrease in TGFBR3 mRNA in tumor stroma in comparison to control tissue. We investigated publicly available databases, and have identified that TGFBR3 mRNA levels are decreased in tumor stroma. We next investigated fibroblast cell lines derived from cancerous and normal breast tissue and found that in addition to mRNA levels, TβRIII protein levels were significantly reduced. Having previously identified that cancer-associated fibroblasts secrete greater levels of tumor promoting cytokines, we investigated the consequences of soluble-TβRIII (sTβRIII) on fibroblasts. Fibroblast conditioned medium was analyzed for 102 human secreted cytokines and distinct changes in response to sTβRIII were observed. Next, we used the fibroblast-conditioned medium to stimulate human monocyte cell line THP-1. These results indicate a distinct transcriptional response depending on sTβRIII treatment and whether it was derived from normal or cancerous breast tissue. We conclude that the effect of TβRIII has distinct roles not only in cancer-associated fibroblasts but that sTβRIII has distinct paracrine functions in the tumor microenvironment., Competing Interests: The authors declare no conflict of interest.

Background: Improved therapies for high-grade glioma (HGG) are urgently needed as the median survival for grade IV gliomas is only 15 months. Bone morphogenetic protein (BMP) signaling plays critical and complex roles in many types of cancer, including glioma, with most of the recently published work focusing on BMP-mediated regulation of glioma stem cells (GSCs). We hypothesized that BMP signaling may be an important modulator of tumorigenic properties in glioma cells outside of the GSC compartment., Methods: We used a human HGG tissue microarray and performed immunohistochemistry for phospho-Smads1,5,8. To examine the role of BMP signaling in tumorigenic astrocytes, transgenic mice were used to delete the BMP type IA receptor (Bmpr1a) and generate astrocytes transformed with oncogenic Ras and homozygous deletion of p53. The cells were transplanted orthotopically into immunocompetent adult host mice., Results: First we established that BMP signaling is active within the vast majority of HGG tumor cells. Mice implanted with BMPR1a-knockout transformed astrocytes showed an increase in median survival compared with mice that received BMPR1a-intact transformed astrocytes (52.5 vs 16 days). In vitro analysis showed that deletion of BMPR1a in oncogenic astrocytes resulted in decreased proliferation, decreased invasion, decreased migration, and increased expression of stemness markers. In addition, inhibition of BMP signaling in murine cells and astrocytoma cells with a small molecule BMP receptor kinase inhibitor resulted in similar tumor suppressive effects in vitro., Conclusion: BMP inhibition may represent a viable therapeutic approach in adult HGG., (© The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Transforming growth factors (TGFs) were discovered as activities that were secreted by cancer cells, and later by normal cells, and had the ability to phenotypically and reversibly transform immortalized fibroblasts. TGF-β distinguished itself from TGF-α because it did not bind to the same epidermal growth factor (EGF) receptor as TGF-α and, therefore, acted through different cell-surface receptors and signaling mediators. This review summarizes the discovery of TGF-β, the early developments in its molecular and biological characterization with its many biological activities in different cell and tissue contexts and its roles in disease, the realization that there is a family of secreted TGF-β-related proteins with many differentiation functions in development and activities in normal cell and tissue physiology, and the subsequent identification and characterization of the receptors and effectors that mediate TGF-β family signaling responses., (Copyright © 2016 Cold Spring Harbor Laboratory Press; all rights reserved.)

Triple-negative breast cancer (TNBC) is a heterogeneous disease that can be classified into distinct molecular subtypes by gene expression profiling. Considered a difficult-to-treat cancer, a fraction of TNBC patients benefit significantly from neoadjuvant chemotherapy and have far better overall survival. Outside of BRCA1/2 mutation status, biomarkers do not exist to identify patients most likely to respond to current chemotherapy; and, to date, no FDA-approved targeted therapies are available for TNBC patients. Previously, we developed an approach to identify six molecular subtypes TNBC (TNBCtype), with each subtype displaying unique ontologies and differential response to standard-of-care chemotherapy. Given the complexity of the varying histological landscape of tumor specimens, we used histopathological quantification and laser-capture microdissection to determine that transcripts in the previously described immunomodulatory (IM) and mesenchymal stem-like (MSL) subtypes were contributed from infiltrating lymphocytes and tumor-associated stromal cells, respectively. Therefore, we refined TNBC molecular subtypes from six (TNBCtype) into four (TNBCtype-4) tumor-specific subtypes (BL1, BL2, M and LAR) and demonstrate differences in diagnosis age, grade, local and distant disease progression and histopathology. Using five publicly available, neoadjuvant chemotherapy breast cancer gene expression datasets, we retrospectively evaluated chemotherapy response of over 300 TNBC patients from pretreatment biopsies subtyped using either the intrinsic (PAM50) or TNBCtype approaches. Combined analysis of TNBC patients demonstrated that TNBC subtypes significantly differ in response to similar neoadjuvant chemotherapy with 41% of BL1 patients achieving a pathological complete response compared to 18% for BL2 and 29% for LAR with 95% confidence intervals (CIs; [33, 51], [9, 28], [17, 41], respectively). Collectively, we provide pre-clinical data that could inform clinical trials designed to test the hypothesis that improved outcomes can be achieved for TNBC patients, if selection and combination of existing chemotherapies is directed by knowledge of molecular TNBC subtypes.

Precision medicine focuses on the management of individual patients on the basis of biomarkers and other distinguishing characteristics, with the overarching objective of improving clinical outcomes. The rapid proliferation of biomarker tests and targeted therapies has revolutionized patient care in a variety of serious disorders. Targeted cancer therapies interrupt oncogenic molecular pathways driven by mutations, overexpression, or translocation of specific genes. However, there is concern that the emergence of large-scale genomic data is exceeding our capacity to appropriately analyze and interpret the results.In 2014, the Institute of Medicine convened the Committee on Policy Issues in the Clinical Development and Use of Biomarkers for Molecularly Targeted Therapies. This committee conducted a study to develop recommendations to address diverse and interconnected development, regulatory, clinical practice, and reimbursement issues. The committee conducted an extensive search of the relevant literature and invited testimony from a wide range of experts in the field. The final report of the committee's study and deliberations was released on March 4, 2016, focusing on ways to achieve 10 goals to further advance the development and appropriate clinical use of biomarker tests for molecularly targeted therapies.This article presents an overview of the committee's study and resulting recommendations, which cover establishment of clinical utility, regulatory oversight, coverage and reimbursement, health system data integration, as well as education and access. The committee's recommendations presented and discussed here are fundamentally grounded in the understanding that, when properly validated and appropriately implemented, these assays and corresponding therapies hold considerable promise to enhance the quality of patient care and improve meaningful clinical outcomes., (© 2016 by American Society of Clinical Oncology.)

Bone morphogenetic protein 4 (BMP4) is a key regulator of cell proliferation and differentiation. In breast cancer cells, BMP4 has been shown to reduce proliferation in vitro and interestingly, in some cases, also to induce migration and invasion. Here we investigated whether BMP4 influences breast cancer metastasis formation by using a xenograft mouse model. MDA-MB-231 breast cancer cells were injected intracardially into mice and metastasis formation was monitored using bioluminescence imaging. Mice treated with BMP4 developed metastases slightly earlier as compared to control animals but the overall number of metastases was similar in both groups (13 in the BMP4 group vs. 12 in controls). In BMP4-treated mice, bone metastases were more common (10 vs. 7) but adrenal gland metastases were less frequent (1 vs. 5) than in controls. Immunostaining revealed no differences in signaling activation, proliferation rate, blood vessel formation, EMT markers or the number of cancer-associated fibroblasts between the treatment groups. In conclusion, BMP4 caused a trend towards accelerated metastasis formation, especially in bone. More work is needed to uncover the long-term effects of BMP4 and the clinical relevance of these findings., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Fibrosis compromises pancreatic ductal carcinoma (PDAC) treatment and contributes to patient mortality, yet antistromal therapies are controversial. We found that human PDACs with impaired epithelial transforming growth factor-β (TGF-β) signaling have high epithelial STAT3 activity and develop stiff, matricellular-enriched fibrosis associated with high epithelial tension and shorter patient survival. In several KRAS-driven mouse models, both the loss of TGF-β signaling and elevated β1-integrin mechanosignaling engaged a positive feedback loop whereby STAT3 signaling promotes tumor progression by increasing matricellular fibrosis and tissue tension. In contrast, epithelial STAT3 ablation attenuated tumor progression by reducing the stromal stiffening and epithelial contractility induced by loss of TGF-β signaling. In PDAC patient biopsies, higher matricellular protein and activated STAT3 were associated with SMAD4 mutation and shorter survival. The findings implicate epithelial tension and matricellular fibrosis in the aggressiveness of SMAD4 mutant pancreatic tumors and highlight STAT3 and mechanics as key drivers of this phenotype.

Contributions of the tumor microenvironment (TME) to progression in thyroid cancer are largely unexplored and may illuminate a basis for understanding rarer aggressive cases of this disease. In this study, we investigated the relationship between the TME and thyroid cancer progression in a mouse model where thyroid-specific expression of oncogenic BRAF and loss of Pten (Braf(V600E)/Pten(-/-)/TPO-Cre) leads to papillary thyroid cancers (PTC) that rapidly progress to poorly differentiated thyroid cancer (PDTC). We found that fibroblasts were recruited to the TME of Braf(V600E)/Pten(-/-)/TPO-Cre thyroid tumors. Conditioned media from cell lines established from these tumors, but not tumors driven by mutant H-ras, induced fibroblast migration and proliferation in vitro Notably, the extracellular matrix of Braf(V600E)/Pten(-/-)/TPO-Cre tumors was enriched with stromal-derived fibrillar collagen, compared with wild-type or Hras-driven tumors. Further, type I collagen enhanced the motility of Braf(V600E)/Pten(-/-)/TPO-Cre tumor cells in vitro In clinical specimens, we found COL1A1 and LOX to be upregulated in PTC and expressed at highest levels in PDTC and anaplastic thyroid cancer. Additionally, increased expression levels of COL1A1 and LOX were associated with decreased survival in thyroid cancer patients. Overall, our results identified fibroblast recruitment and remodeling of the extracellular matrix as pivotal features of the TME in promoting thyroid cancer progression, illuminating candidate therapeutic targets and biomarkers in advanced forms of this malignancy. Cancer Res; 76(7); 1804-13. ©2016 AACR., (©2016 American Association for Cancer Research.)

Background & Aims: A hallmark of pancreatic ductal adenocarcinoma (PDAC) is the presence of a dense desmoplastic reaction (stroma) that impedes drug delivery to the tumor. Attempts to deplete the tumor stroma have resulted in formation of more aggressive tumors. We have identified signal transducer and activator of transcription (STAT) 3 as a biomarker of resistance to cytotoxic and molecularly targeted therapy in PDAC. The purpose of this study is to investigate the effects of targeting STAT3 on the PDAC stroma and on therapeutic resistance., Methods: Activated STAT3 protein expression was determined in human pancreatic tissues and tumor cell lines. In vivo effects of AZD1480, a JAK/STAT3 inhibitor, gemcitabine or the combination were determined in Ptf1a(cre/+);LSL-Kras(G12D/+);Tgfbr2(flox/flox) (PKT) mice and in orthotopic tumor xenografts. Drug delivery was analyzed by matrix-assisted laser desorption/ionization imaging mass spectrometry. Collagen second harmonic generation imaging quantified tumor collagen alignment and density., Results: STAT3 activation correlates with decreased survival and advanced tumor stage in patients with PDAC. STAT3 inhibition combined with gemcitabine significantly inhibits tumor growth in both an orthotopic and the PKT mouse model of PDAC. This combined therapy attenuates in vivo expression of SPARC, increases microvessel density, and enhances drug delivery to the tumor without depletion of stromal collagen or hyaluronan. Instead, the PDAC tumors demonstrate vascular normalization, remodeling of the tumor stroma, and down-regulation of cytidine deaminase., Conclusions: Targeted inhibition of STAT3 combined with gemcitabine enhances in vivo drug delivery and therapeutic response in PDAC. These effects occur through tumor stromal remodeling and down-regulation of cytidine deaminase without depletion of tumor stromal content., (Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Purpose: Wilms tumor is the most common renal neoplasm of childhood. We previously found that restricted activation of the WNT/β-catenin pathway in renal epithelium late in kidney development is sufficient to induce small primitive neoplasms with features of epithelial Wilms tumor. Metastatic disease progression required simultaneous addition of an activating mutation of the oncogene K-RAS. We sought to define the molecular pathways activated in this process and their relationship to human renal malignancies., Materials and Methods: Affymetrix® expression microarray data from murine kidneys with activation of K-ras and/or Ctnnb1 (β-catenin) restricted to renal epithelium were analyzed and compared to publicly available expression data on normal and neoplastic human renal tissue. Target genes were verified by immunoblot and immunohistochemistry., Results: Mouse kidney tumors with activation of K-ras and Ctnnb1, and human renal malignancies had similar mRNA expression signatures and were associated with activation of networks centered on β-catenin and TP53. Up-regulation of WNT/β-catenin targets (MYC, Survivin, FOXA2, Axin2 and Cyclin D1) was confirmed by immunoblot. K-RAS/β-catenin murine kidney tumors were more similar to human Wilms tumor than to other renal malignancies and demonstrated activation of a TP53 dependent network of genes, including the transcription factor E2F1. Up-regulation of E2F1 was confirmed in murine and human Wilms tumor samples., Conclusions: Simultaneous activation of K-RAS and β-catenin in embryonic renal epithelium leads to neoplasms similar to human Wilms tumor and associated with activation of TP53 and up-regulation of E2F1. Further studies are warranted to evaluate the role of TP53 and E2F1 in human Wilms tumor., (Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

The bone morphogenetic protein (BMP) pathway belonging to the Transforming Growth Factor beta (TGFβ) family of secreted cytokines/growth factors is an important regulator of cancer. BMP ligands have been shown to play both tumor suppressive and promoting roles in human cancers. We have found that BMP ligands are amplified in human ovarian cancers and that BMP receptor expression correlates with poor progression-free-survival (PFS). Furthermore, active BMP signaling has been observed in human ovarian cancer tissue. We also determined that ovarian cancer cell lines have active BMP signaling in a cell autonomous fashion. Inhibition of BMP signaling with a small molecule receptor kinase antagonist is effective at reducing ovarian tumor sphere growth. Furthermore, BMP inhibition can enhance sensitivity to Cisplatin treatment and regulates gene expression involved in platinum resistance in ovarian cancer. Overall, these studies suggest targeting the BMP pathway as a novel source to enhance chemo-sensitivity in ovarian cancer., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Bone Morphogenetic Proteins (BMPs) are secreted cytokines/growth factors belonging to the Transforming Growth Factor β (TGFβ) family. BMP ligands have been shown to be overexpressed in human breast cancers. Normal and cancerous breast tissue display active BMP signaling as indicated by phosphorylated Smads 1, 5 and 9. We combined mice expressing the MMTV.PyMT oncogene with mice having conditional knockout (cKO) of BMP receptor type 1a (BMPR1a) using whey acidic protein (WAP)-Cre and found this deletion resulted in delayed tumor onset and significantly extended survival. Immunofluorescence staining revealed that cKO tumors co-expressed Keratin 5 and mesenchymal cell markers such as Vimentin. This indicates that epithelial-to-mesenchymal (EMT)-like transitions occurred in cKO tumors. We performed microarray analysis on these tumors and found changes that support EMT-like changes. We established primary tumor cell lines and found that BMPR1a cKO had slower growth in vitro and in vivo upon implantation. cKO tumor cells had reduced migration in vitro. We analyzed human databases from TCGA and survival data from microarrays to confirm BMPR1a tumor promoting functions, and found that high BMPR1a gene expression correlates with decreased survival regardless of molecular breast cancer subtype. In conclusion, the data indicate that BMP signaling through BMPR1a functions as a tumor promoter.

Bone morphogenetic proteins (BMPs) are secreted cytokines/growth factors that have differing roles in cancer. BMPs are overexpressed in human breast cancers, but loss of BMP signaling in mammary carcinomas can accelerate metastasis. We show that human breast cancers display active BMP signaling, which is rarely downregulated or homozygously deleted. We hypothesized that systemic inhibition of BMP signaling in both the tumor and the surrounding microenvironment could prevent tumor progression and metastasis. To test this hypothesis, we used DMH1, a BMP antagonist, in MMTV.PyVmT expressing mice. Treatment with DMH1 reduced lung metastasis and the tumors were less proliferative and more apoptotic. In the surrounding tumor microenvironment, treatment with DMH1 altered fibroblasts, lymphatic vessels and macrophages to be less tumor promoting. These results indicate that inhibition of BMP signaling may successfully target both the tumor and the surrounding microenvironment to reduce tumor burden and metastasis.

Postnatal mammary gland development and differentiation occur during puberty and pregnancy. To explore the role of DNA methylation in these processes, we determined the genome-wide DNA methylation and gene expression profiles of CD24(+)CD61(+)CD29(hi), CD24(+)CD61(+)CD29(lo), and CD24(+)CD61(-)CD29(lo) cell populations that were previously associated with distinct biological properties at different ages and reproductive stages. We found that pregnancy had the most significant effects on CD24(+)CD61(+)CD29(hi) and CD24(+)CD61(+)CD29(lo) cells, inducing distinct epigenetic states that were maintained through life. Integrated analysis of gene expression, DNA methylation, and histone modification profiles revealed cell-type- and reproductive-stage-specific changes. We identified p27 and TGFβ signaling as key regulators of CD24(+)CD61(+)CD29(lo) cell proliferation, based on their expression patterns and results from mammary gland explant cultures. Our results suggest that relatively minor changes in DNA methylation occur during luminal differentiation compared with the effects of pregnancy on CD24(+)CD61(+)CD29(hi) and CD24(+)CD61(+)CD29(lo) cells., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

Metastasis is the most devastating aspect of cancer, however we know very little about the mechanisms of local invasion, the earliest step of metastasis. During tumor growth CD11b+ Gr1+ cells, known also as MDSCs, have been shown to promote tumor progression by a wide spectrum of effects that suppress the anti-tumor immune response. In addition to immunosuppression, CD11b+ Gr1+ cells promote metastasis by mechanisms that are currently unknown. CD11b+ Gr1+ cells localize near fibroblasts, which remodel the ECM and leave tracks for collective cell migration of carcinoma cells. In this study we discovered that CD11b+ Gr1+ cells promote invasion of mammary carcinoma cells by increasing fibroblast migration. This effect was directed by secreted factors derived from CD11b+ Gr1+ cells. We have identified several CD11b+ Gr1+ cell secreted proteins that activate fibroblast migration, including CXCL11, CXCL15, FGF2, IGF-I, IL1Ra, Resistin, and Shh. The combination of CXCL11 and FGF2 had the strongest effect on fibroblast migration that is associated with Akt1 and ERK1/2 phosphorylation. Analysis of subsets of CD11b+ Gr1+ cells identified that CD11b+ Ly6Chigh Ly6Glow cells increase fibroblast migration more than other myeloid cell populations. Additionally, tumor-derived CD11b+ Gr1+ cells promote fibroblast migration more than splenic CD11b+ Gr1+ cells of tumor-bearing mice. While TGFβ signaling in fibroblasts does not regulate their migration toward CD11b+ Gr1+ cells, however deletion of TGFβ receptor II on CD11b+ Gr1+ cells downregulates CXCL11, Shh, IGF1 and FGF2 resulting in reduced fibroblast migration. These studies show that TGFβ signaling in CD11b+ Gr1+ cells promotes fibroblast directed carcinoma invasion and suggests that perivascular CD11b+ Ly6Chigh Ly6Glow cells may be the stimulus for localized invasion leading to metastasis.

Bone Morphogenetic Protein (BMP) receptors mediate a diverse range of signals to regulate both development and disease. BMP activity has been linked to both tumor promoting and suppressive functions in both tumor cells and their surrounding microenvironment. We sought to investigate the requirement for BMPR2 in stromal fibroblasts during mammary tumor formation and metastasis. We utilized FSP1 (Fibroblast Specific Protein-1) promoter driven Cre to genetically delete BMPR2 in mice expressing the MMTV.PyVmT mammary carcinoma oncogene. We found that abrogation of stromal BMPR2 expression via FSP1 driven Cre resulted in increased tumor metastasis. Additionally, similar to epithelial BMPR2 abrogation, stromal loss of BMPR2 results in increased inflammatory cell infiltration. We proceeded to isolate and establish fibroblast cell lines without BMPR2 and found a cell autonomous increase in inflammatory cytokine secretion. Fibroblasts were co-implanted with syngeneic tumor cells and resulted in accelerated tumor growth and increased metastasis when fibroblasts lacked BMPR2. We observed that the loss of BMPR2 results in increased chemokine expression, which facilitates inflammation by a sustained increase in myeloid cells. The chemokines increased in BMPR2 deleted cells correlated with poor outcome in human breast cancer patients. We conclude that BMPR2 has tumor suppressive functions in the stroma by regulating inflammation., (Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.)

Although the etiology of squamous cell carcinomas of the oral mucosa is well understood, the cellular origin and the exact molecular mechanisms leading to their formation are not. Previously, we observed the coordinated loss of E-cadherin (CDH1) and transforming growth factor beta receptor II (TGFBR2) in esophageal squamous tumors. To investigate if the coordinated loss of Cdh1 and Tgfbr2 is sufficient to induce tumorigenesis in vivo, we developed two mouse models targeting ablation of both genes constitutively or inducibly in the oral-esophageal epithelium. We show that the loss of both Cdh1 and Tgfbr2 in both models is sufficient to induce squamous cell carcinomas with animals succumbing to the invasive disease by 18 months of age. Advanced tumors have the ability to invade regional lymph nodes and to establish distant pulmonary metastasis. The mouse tumors showed molecular characteristics of human tumors such as overexpression of Cyclin D1. We addressed the question whether TGFβ signaling may target known stem cell markers and thereby influence tumorigenesis. From our mouse and human models, we conclude that TGFβ signaling regulates key aspects of stemness and quiescence in vitro and in vivo. This provides a new explanation for the importance of TGFβ in mucosal homeostasis., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Introduction: Transforming growth factor beta (TGFβ) plays a major role in the regulation of tumor initiation, progression, and metastasis. It is depended on the type II TGFβ receptor (TβRII) for signaling. Previously, we have shown that deletion of TβRII in mammary epithelial of MMTV-PyMT mice results in shortened tumor latency and increased lung metastases. However, active TGFβ signaling increased the number of circulating tumor cells and metastases in MMTV-Neu mice. In the current study, we describe a newly discovered connection between attenuated TGFβ signaling and human epidermal growth factor receptor 2 (HER2) signaling in mammary tumor progression., Methods: All studies were performed on MMTV-Neu mice with and without dominant-negative TβRII (DNIIR) in mammary epithelium. Mammary tumors were analyzed by flow cytometry, immunohistochemistry, and immunofluorescence staining. The levels of secreted proteins were measured by enzyme-linked immunosorbent assay. Whole-lung mount staining was used to quantitate lung metastasis. The Cancer Genome Atlas (TCGA) datasets were used to determine the relevance of our findings to human breast cancer., Results: Attenuated TGFβ signaling led to a delay tumor onset, but increased the number of metastases in MMTVNeu/DNIIR mice. The DNIIR tumors were characterized by increased vasculogenesis, vessel leakage, and increased expression of vascular endothelial growth factor (VEGF). During DNIIR tumor progression, both the levels of CXCL1/5 and the number of CD11b+Gr1+ cells and T cells decreased. Analysis of TCGA datasets demonstrated a significant negative correlation between TGFBR2 and VEGF genes expression. Higher VEGFA expression correlated with shorter distant metastasis-free survival only in HER2+ patients with no differences in HER2-, estrogen receptor +/- or progesterone receptor +/- breast cancer patients., Conclusion: Our studies provide insights into a novel mechanism by which epithelial TGFβ signaling modulates the tumor microenvironment, and by which it is involved in lung metastasis in HER2+ breast cancer patients. The effects of pharmacological targeting of the TGFβ pathway in vivo during tumor progression remain controversial. The targeting of TGFβ signaling should be a viable option, but because VEGF has a protumorigenic effect on HER2+ tumors, the targeting of this protein could be considered when it is associated with attenuated TGFβ signaling.

There is growing evidence that generation of adenosine from ATP, which is mediated by the CD39/CD73 enzyme pair, predetermines immunosuppressive and proangiogenic properties of myeloid cells. We have previously shown that the deletion of the TGF-β type II receptor gene (Tgfbr2) expression in myeloid cells is associated with decreased tumor growth, suggesting protumorigenic effect of TGF-β signaling. In this study, we tested the hypothesis that TGF-β drives differentiation of myeloid-derived suppressor cells into protumorigenic terminally differentiated myeloid mononuclear cells (TDMMCs) characterized by high levels of cell-surface CD39/CD73 expression. We found that TDMMCs represent a major cell subpopulation expressing high levels of both CD39 and CD73 in the tumor microenvironment. In tumors isolated from mice with spontaneous tumor formation of mammary gland and conditional deletion of the type II TGF-β receptor in mammary epithelium, an increased level of TGF-β protein was associated with further increase in number of CD39(+)CD73(+) TDMMCs compared with MMTV-PyMT/TGFβRII(WT) control tumors with intact TGF-β signaling. Using genetic and pharmacological approaches, we demonstrated that the TGF-β signaling mediates maturation of myeloid-derived suppressor cells into TDMMCs with high levels of cell surface CD39/CD73 expression and adenosine-generating capacity. Disruption of TGF-β signaling in myeloid cells resulted in decreased accumulation of TDMMCs, expressing CD39 and CD73, and was accompanied by increased infiltration of T lymphocytes, reduced density of blood vessels, and diminished progression of both Lewis lung carcinoma and spontaneous mammary carcinomas. We propose that TGF-β signaling can directly induce the generation of CD39(+)CD73(+) TDMMCs, thus contributing to the immunosuppressive, proangiogenic, and tumor-promoting effects of this pleiotropic effector in the tumor microenvironment., (Copyright © 2014 by The American Association of Immunologists, Inc.)

Introduction: There is a major need to better understand the molecular basis of triple negative breast cancer (TNBC) in order to develop effective therapeutic strategies. Using gene expression data from 587 TNBC patients we previously identified six subtypes of the disease, among which a mesenchymal-stem like (MSL) subtype. The MSL subtype has significantly higher expression of the transforming growth factor beta (TGF-β) pathway-associated genes relative to other subtypes, including the TGF-β receptor type III (TβRIII). We hypothesize that TβRIII is tumor promoter in mesenchymal-stem like TNBC cells., Methods: Representative MSL cell lines SUM159, MDA-MB-231 and MDA-MB-157 were used to study the roles of TβRIII in the MSL subtype. We stably expressed short hairpin RNAs specific to TβRIII (TβRIII-KD). These cells were then used for xenograft tumor studies in vivo; and migration, invasion, proliferation and three dimensional culture studies in vitro. Furthermore, we utilized human gene expression datasets to examine TβRIII expression patterns across all TNBC subtypes., Results: TβRIII was the most differentially expressed TGF-β signaling gene in the MSL subtype. Silencing TβRIII expression in MSL cell lines significantly decreased cell motility and invasion. In addition, when TβRIII-KD cells were grown in a three dimensional (3D) culture system or nude mice, there was a loss of invasive protrusions and a significant decrease in xenograft tumor growth, respectively. In pursuit of the mechanistic underpinnings for the observed TβRIII-dependent phenotypes, we discovered that integrin-α2 was expressed at higher level in MSL cells after TβRIII-KD. Stable knockdown of integrin-α2 in TβRIII-KD MSL cells rescued the ability of the MSL cells to migrate and invade at the same level as MSL control cells., Conclusions: We have found that TβRIII is required for migration and invasion in vitro and xenograft growth in vivo. We also show that TβRIII-KD elevates expression of integrin-α2, which is required for the reduced migration and invasion, as determined by siRNA knockdown studies of both TβRIII and integrin-α2. Overall, our results indicate a potential mechanism in which TβRIII modulates integrin-α2 expression to effect MSL cell migration, invasion, and tumorigenicity.

Pancreatic ductal adenocarcinoma (PDAC) is associated with marked fibrosis and stromal myofibroblasts, but their functional contribution remains unknown. Transgenic mice with the ability to delete αSMA(+) myofibroblasts in pancreatic cancer were generated. Depletion starting at either noninvasive precursor (pancreatic intraepithelial neoplasia) or the PDAC stage led to invasive, undifferentiated tumors with enhanced hypoxia, epithelial-to-mesenchymal transition, and cancer stem cells, with diminished animal survival. In PDAC patients, fewer myofibroblasts in their tumors also correlated with reduced survival. Suppressed immune surveillance with increased CD4(+)Foxp3(+) Tregs was observed in myofibroblast-depleted mouse tumors. Although myofibroblast-depleted tumors did not respond to gemcitabine, anti-CTLA4 immunotherapy reversed disease acceleration and prolonged animal survival. This study underscores the need for caution in targeting carcinoma-associated fibroblasts in PDAC., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The dissemination of prostate cancer to bone is a common, incurable aspect of advanced disease. Prevention and treatment of this terminal phase of prostate cancer requires improved molecular understanding of the process as well as markers indicative of molecular progression. Through biochemical analyses and loss-of-function in vivo studies, we demonstrate that the cell adhesion molecule, activated leukocyte cell adhesion molecule (ALCAM), is actively shed from metastatic prostate cancer cells by the sheddase ADAM17 in response to TGF-β. Not only is this posttranslational modification of ALCAM a marker of prostate cancer progression, the molecule is also required for effective metastasis to bone. Biochemical analysis of prostate cancer cell lines reveals that ALCAM expression and shedding is elevated in response to TGF-β signaling. Both in vitro and in vivo shedding is mediated by ADAM17. Longitudinal analysis of circulating ALCAM in tumor-bearing mice revealed that shedding of tumor, but not host-derived ALCAM is elevated during growth of the cancer. Gene-specific knockdown of ALCAM in bone-metastatic PC3 cells greatly diminished both skeletal dissemination and tumor growth in bone. The reduced growth of ALCAM knockdown cells corresponded to an increase in apoptosis (caspase-3) and decreased proliferation (Ki67). Together, these data demonstrate that the ALCAM is both a functional regulator as well as marker of prostate cancer progression., (©2014 AACR)

The influence of the microenvironment on tumour progression is becoming clearer. In this Review we address the role of an essential signalling pathway, that of transforming growth factor-β, in the regulation of components of the tumour microenvironment and how this contributes to tumour progression.

The tumor stromal environment can dictate many aspects of tumor progression. A complete understanding of factors driving stromal activation and their role in tumor metastasis is critical to furthering research with the goal of therapeutic intervention. Polyoma middle T-induced mammary carcinomas lacking the type II TGF-β receptor (PyMT(mgko)) are highly metastatic compared with control PyMT-induced carcinomas (PyMT(fl/fl)). We hypothesized that the PyMT(mgko)-activated stroma interacts with carcinoma cells to promote invasion and metastasis. We show that the extracellular matrix associated with PyMT(mgko) tumors is stiffer and has more fibrillar collagen and increased expression of the collagen crosslinking enzyme lysyl oxidase (LOX) compared with PyMT(fl/fl) mammary carcinomas. Inhibition of LOX activity in PyMT(mgko) mice had no effect on tumor latency and size, but significantly decreased tumor metastasis through inhibition of tumor cell intravasation. This phenotype was associated with a decrease in keratin 14-positive myoepithelial cells in PyMT(mgko) tumors following LOX inhibition as well as a decrease in focal adhesion formation. Interestingly, the primary source of LOX was found to be activated fibroblasts. LOX expression in these fibroblasts can be driven by myeloid cell-derived TGF-β, which is significantly linked to human breast cancer. Overall, stromal expansion in PyMT(mgko) tumors is likely caused through the modulation of immune cell infiltrates to promote fibroblast activation. This feeds back to the epithelium to promote metastasis by modulating phenotypic characteristics of basal cells. Our data indicate that epithelial induction of microenvironmental changes can play a significant role in tumorigenesis and attenuating these changes can inhibit metastasis. Cancer Res; 73(17); 5336-46. ©2013 AACR.

Bone Morphogenetic Proteins (BMPs) are secreted cytokines that are part of the Transforming Growth Factor β (TGFβ) superfamily. BMPs have been shown to be highly expressed in human breast cancers, and loss of BMP signaling in mammary carcinomas has been shown to accelerate metastases. Interestingly, other work has indicated that stimulation of dermal fibroblasts with BMP can enhance secretion of pro-tumorigenic factors. Furthermore, treatment of carcinoma-associated fibroblasts (CAFs) derived from a mouse prostate carcinoma with BMP4 was shown to stimulate angiogenesis. We sought to determine the effect of BMP treatment on mammary fibroblasts. A large number of secreted pro-inflammatory cytokines and matrix-metallo proteases (MMPs) were found to be upregulated in response to BMP4 treatment. Fibroblasts that were stimulated with BMP4 were found to enhance mammary carcinoma cell invasion, and these effects were inhibited by a BMP receptor kinase antagonist. Treatment with BMP in turn elevated pro-tumorigenic secreted factors such as IL-6 and MMP-3. These experiments demonstrate that BMP may stimulate tumor progression within the tumor microenvironment.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most deadly cancers worldwide. Although many regimens have been used for PDAC treatment, the combination of the EGF receptor (EGFR) inhibitor erlotinib with gemcitabine has been the only molecular-targeted drug tested so far that has been superior to gemcitabine alone. The mechanism underlying this effective combinational regimen remains unknown. Here, we show that the combination is superior to gemcitabine alone in blocking progression and prolonging survival in a murine model of PDAC (Kras activation with Tgfbr2 knockout). We found that gemcitabine induced mitogen-activated protein kinase signaling, which was dramatically inhibited by erlotinib even in the Kras-activated PDAC cells in the mouse model. Mechanistic investigations suggested that gemcitabine induces EGFR ligand expression and ERBB2 activation by increasing heterodimer formation with EGFR, thereby maintaining high levels of ERBB2 protein in PDAC cells. Overall, our findings suggest a significant role of ERBB in PDAC treatment., (©2013 AACR.)

c-Jun N-terminal kinase (JNK) is a member of the mitogen-activated protein kinase (MAPK) family, and it is reportedly involved in the development of several cancers. However, the role of JNK in pancreatic cancer has not been elucidated. We assessed t he involvement of JNK in the development of pancreatic cancer and investigated the therapeutic effect of JNK inhibitors on this deadly cancer. Small interfering RNAs against JNK or the JNK inhibitor SP600125 were used to examine the role of JNK in cellular proliferation and the cell cycles of pancreatic cancer cell lines. Ptf1a(cre/+) ;LSL-Kras(G12D/+) ;Tgfbr2(flox/flox) mice were treated with the JNK inhibitor to examine pancreatic histology and survival. The effect of JNK inhibition on tumor angiogenesis was also assessed using cell lines and murine pancreatic cancer specimens. JNK was frequently activated in human and murine pancreatic cancer in vitro and in vivo. Growth of human pancreatic cancer cell lines was suppressed by JNK inhibition through G1 arrest in the cell cycle with decreased cyclin D1 expression. In addition, oncogenic K-ras expression led to activation of JNK in pancreatic cancer cell lines. Treatment of Ptf1a(cre/+) ;LSL-Kras(G12D/+) ;Tgfbr2(flox/flox) mice with the JNK inhibitor decreased growth of murine pancreatic cancer and prolonged survival of the mice significantly. Angiogenesis was also decreased by JNK inhibition in vitro and in vivo. In conclusion, activation of JNK promotes development of pancreatic cancer, and JNK may be a potential therapeutic target for pancreatic cancer., (© 2012 Japanese Cancer Association.)

By crossing LysM-Cre and TGF-β type II receptor (Tgfbr2) floxed mice we achieved specific deletion of Tgfbr2 in myeloid cells (Tgfbr2(MyeKO) mice). S.c.-injected (LLC, EL4-OVA) and implanted (MMTV-PyMT) carcinoma cells grow slower in Tgfbr2(MyeKO) mice. The number of CD45(+) cells in the tumor tissue was the same in both genotypes of mice, but upon analysis, the percentage of T cells (CD45(+)CD3(+)) in the KO mice was increased. By flow cytometry analysis, we did not detect any differences in the number and phenotype of TAMs, CD11b(+)Gr1(+), and DCs in Tgfbr2(MyeKO) compared with Tgfbr2(MyeWT) mice. ELISA and qRT-PCR data showed differences in myeloid cell functions. In Tgfbr2(MyeKO) TAMs, TNF-α secretion was increased, basal IL-6 secretion was down-regulated, TGF-β did not induce any VEGF response, and there was decreased MMP9 and increased MMP2 and iNOS expression. TGF-β did not have any effect on CD11b(+)Gr1(+) cells isolated from Tgfbr2(MyeKO) mice in the regulation of Arg, iNOS, VEGF, and CXCR4, and moreover, these cells have decreased suppressive activity relative to T cell proliferation. Also, we found that DCs from tumor tissue of Tgfbr2(MyeKO) mice have increased antigen-presented properties and an enhanced ability to stimulate antigen-specific T cell proliferation. We conclude that Tgfbr2 in myeloid cells has a negative role in the regulation of anti-tumorigenic functions of these cells, and deletion of this receptor decreases the suppressive function of CD11b(+)Gr1(+) cells and increases antigen-presenting properties of DCs and anti-tumorigenic properties of TAMs.

Indoleamine 2,3-dioxygenase (IDO) is overexpressed in many human cancers and is believed to play a role in tumor immune evasion, but a requirement for IDO in tumor progression has not been formally shown. The study by Smith and colleagues in this issue of Cancer Discovery provides genetic evidence for the importance of IDO in tumorigenesis, which supports the use of IDO inhibitors in clinical trials in humans., (Cancer Discov; 2(8); 673-5. ©2012 AACR.)