Inflammatory Regulation by TNF-α-Activated Adipose-Derived Stem Cells in the Human Bladder Cancer Microenvironment

Mesenchymal stem cells (MSCs), such as adipose-derived stem cells (ADSCs), have the most impressive ability to reduce inflammation through paracrine growth factors and cytokines that participate in inflammation. Tumor necrosis factor (TNF)-α bioactivity is a prerequisite in several inflammatory and autoimmune disease models. This study investigated the effects of TNF-α stimulate on ADSCs in the tumor microenvironment. The RNAseq analysis and cytokines assay demonstrated that TNF-α stimulated ADSCs proliferation and pro-inflammatory genes that correlated to leukocytes differentiation were upregulated. We found that upregulation of TLR2 or PTGS2 toward to IRF7 gene-associated with immunomodulatory and antitumor pathway under TNF-α treatment. In TNF-α–treated ADSCs cultured with the bladder cancer (BC) cell medium, the results showed that apoptosis ratio and OCT-4 and TLR2 genes which maintained the self-renewal ability of stem cells were decreased. Furthermore, the cell survival regulation genes including TRAF1, NF-kB, and IRF7 were upregulated in TNF-α–treated ADSCs. Additionally, these genes have not been upregulated in BC cell medium. A parallel study showed that tumor progressing genes were downregulated in TNF-α–treated ADSCs. Hence, the study suggests that TNF-α enhances the immunomodulatory potential of ADSCs during tumorigenesis and provides insight into highly efficacious MSC-based therapeutic options for BC.

Differential functional roles of fibroblasts and pericytes in the formation of tissue-engineered microvascular networks in vitro

Formation of a perfusable microvascular network (μVN) is critical for tissue engineering of solid organs. Stromal cells can support endothelial cell (EC) self-assembly into a μVN, but distinct stromal cell populations may play different roles in this process. Here we describe the differential effects that two widely used stromal cell populations, fibroblasts (FBs) and pericytes (PCs), have on μVN formation. We examined the effects of adding defined stromal cell populations on the self-assembly of ECs derived from human endothelial colony forming cells (ECFCs) into perfusable μVNs in fibrin gels cast within a microfluidic chamber. ECs alone failed to fully assemble a perfusable μVN. Human lung FBs stimulated the formation of EC-lined μVNs within microfluidic devices. RNA-seq analysis suggested that FBs produce high levels of hepatocyte growth factor (HGF). Addition of recombinant HGF improved while the c-MET inhibitor, Capmatinib (INCB28060), reduced μVN formation within devices. Human placental PCs could not substitute for FBs, but in the presence of FBs, PCs closely associated with ECs, formed a common basement membrane, extended microfilaments intercellularly, and reduced microvessel diameters. Different stromal cell types provide different functions in microvessel assembly by ECs. FBs support μVN formation by providing paracrine growth factors whereas PCs directly interact with ECs to modify microvascular morphology.

Differential functional roles of fibroblasts and pericytes in the formation of tissue-engineered microvascular networks in vitro

AimsFormation of a perfusable microvascular network (μVN) is critical for tissue engineering of solid organs. Stromal cells can support endothelial cell (EC) self-assembly into a μVN, but distinct stromal cell populations may play different roles in this process. Here we investigated the effects that two widely used stromal cells populations, fibroblasts (FBs) and pericytes (PCs), have on μVN formation.Methods and resultsWe examined the effects of adding defined stromal cell populations on the self-assembly of ECs derived from human endothelial colony forming cells (ECFCs) into perfusable μVNs in fibrin gels cast within a microfluidics chamber. ECs alone fail to fully assemble a perfusable μVN. Human lung FBs stimulate the formation of EC lined μVNs within microfluidic devices. RNA-seq analysis suggested that FBs produce high levels of hepatocyte growth factor (HGF), and addition of recombinant HGF improved μVN formation within devices. Human placental PCs could not substitute for FBs, but in the presence of FBs, PCs closely associated with ECs, formed a common basement membrane, extended microfilaments intercellularly, and reduced microvessel diameters.ConclusionsDifferent stromal cell types provide different functions in microvessel assembly by ECs. FBs support μVN formation by providing paracrine growth factors whereas PCs directly interact with ECs to modify microvascular morphology.Statement of ContributionNatalia Kosyakova, Derek Kao, William G. Chang were primarily responsible for the conception, design, interpretation of experiments, and drafting of the manuscript. Francesc López-Giráldez carried out analysis of RNA-seq data. Susann Spindler and Gregory Tietjen assisted with microvessel analysis software. Morven Graham and Xinran Liu assisted with the electron microscopy. Kevin J. James and Jee Won Shin assisted with data collection. Jordan Pober assisted with a critical review of manuscript and experimental design.

Abstract 18448: Laminar Flow and Klf2 Regulate the Paracrine Activity of Endothelial Cells by Modulating the Balance of Cxcr4 versus Cxcr7 Expression

Recent studies suggest that endothelial cells are not only important for oxygen delivery but act as paracrine source for signals that determine tissue regeneration versus fibrosis. The paracrine regulation of liver regeneration by endothelial cells was shown to be critically controlled by the SDF-1 receptors CXCR4, which was shown to control the release of pro-fibrotic cytokines, whereas signaling via the CXCR7 receptor was shown to provide a pro-regenerative niche. The regulation of the endothelial CXCR4 versus CXCR7 expression and their role in heart regeneration is unclear. Here we show that laminar flow as well as the expression of the flow-induced transcription factor Krüppel-like factor 2 (KLF2) reduced mRNA expression of CXCR4 by (0.34±0.01 fold; p<0.005) and (0.22±0.05 fold; p<0.0005), respectively, whereas CXCR7 expression was significantly increased (flow: 6.59±0.52 fold; p<0.005, KLF2: 36±12.3 fold; p<0.05). Western blots confirmed that flow and KLF2 critically modulate the CXCR4 / CXCR7 protein expression. Interestingly, shear stress and KLF2 induce the expression of the CXCR7-downstream inhibitor of DNA binding 1 (Id1), a transcription factor known to induce pro-regenerative angiocrine factors. Cytokine arrays further demonstrate that flow and KLF2 overexpression change the paracrine release of important growth factors. For example, Activin A (1.7±0.69 fold) and IGF-binding proteins were increased (1.7±0.87 fold), whereas the release of pro-inflammatory cytokines IL-8 (0.16±0.02 fold) and MCP1 (0.43±0.01 fold) and growth factors VEGF-C (0.16±0.01 fold), PlGF (0.09±0.01 fold) and Endoglin (0.27±0.09 fold) were reduced. The changes in the release of these paracrine growth factors were partially reduced by siRNA-mediated silencing of CXCR7. In summary these data suggest that flow and KLF2 critically regulate the paracrine secretion of endothelial growth factors by modulating the balance of CXCR4 versus CXCR7 expression. Ongoing studies address the contribution of endothelial KLF2 in liver and heart regeneration in vivo.

Molecular brakes regulating mTORC1 activation in skeletal muscle following synergist ablation

The goal of the current work was to profile positive (mTORC1 activation, autocrine/paracrine growth factors) and negative [AMPK, unfolded protein response (UPR)] pathways that might regulate overload-induced mTORC1 (mTOR complex 1) activation with the hypothesis that a number of negative regulators of mTORC1 will be engaged during a supraphysiological model of hypertrophy. To achieve this, mTORC1-IRS-1/2 signaling, BiP/CHOP/IRE1α, and AMPK activation were determined in rat plantaris muscle following synergist ablation (SA). SA resulted in significant increases in muscle mass of ∼4% per day throughout the 21 days of the experiment. The expression of the insulin-like growth factors (IGF) were high throughout the 21st day of overload. However, IGF signaling was limited, since IRS-1 and -2 were undetectable in the overloaded muscle from day 3 to day 9. The decreases in IRS-1/2 protein were paralleled by increases in GRB10 Ser501/503 and S6K1 Thr389 phosphorylation, two mTORC1 targets that can destabilize IRS proteins. PKB Ser473 phosphorylation was higher from 3–6 days, and this was associated with increased TSC2 Thr939 phosphorylation. The phosphorylation of TSC2 Thr1345 (an AMPK site) was also elevated, whereas phosphorylation at the other PKB site, Thr1462, was unchanged at 6 days. In agreement with the phosphorylation of Thr1345, SA led to activation of AMPKα1 during the initial growth phase, lasting the first 9 days before returning to baseline by day 12. The UPR markers CHOP and BiP were elevated over the first 12 days following ablation, whereas IRE1α levels decreased. These data suggest that during supraphysiological muscle loading at least three potential molecular brakes engage to downregulate mTORC1.

Intermittent (IAD) versus continuous androgen deprivation (CAD) in hormone sensitive metastatic prostate cancer (HSM1PC) patients (pts): Results of S9346 (INT-0162), an international phase III trial.

4 Background: Castration resistance occurs in the vast majority of HSM1PC pts treated with AD, with a median survival of 2.5 years (y). It is in part an adaptive process with activation of genes resulting in the production of autocrine/paracrine growth factors that contribute to maintaining the viability of PC cells. Replacing androgens before castration resistance is hypothesized to maintain PC androgen-dependence. Preclinically IAD prolonged time to castration resistance and early clinical data indicated feasibility and potential for better quality of life. Methods: HSM1PC pts with performance status (PS) 0-2, PSA ≥ 5 ng/ml were treated with 7 months (m) of goserelin + bicalutamide. Pts achieving PSA ≤4 ng/ml on m 6 and 7 were stratified by prior neoadjuvant AD/finasteride, PS and disease extent (minimal, extensive) and randomized to CAD or IAD. Primary objective: To assess if overall survival (OS) with IAD is noninferior to CAD using a one-sided test with an upper bound hazard ratio=1.20, adjusting for stratification factors. Sample size: 756 pts/arm, type I and II error rates of 0.05 and 0.10. Results: 3,040 pts were accrued by SWOG, CALGB, ECOG, NCIC, and EORTC (5/95- 9/08). After 7 m of CAD, 1535 eligible pts achieved PSA ≤4.0 (median age 70 yrs, 4% PS 2, 48% extensive disease, 12% prior neoadjuvant AD) and were randomized to CAD (759 pts) or IAD (770 pts). Grade 3/4 related adverse events: IAD 30.3%, CAD 32.6%. Median follow-up was 9.2 yrs. Median and 10 yr OS: All eligible pts from study entry: 3.6 yrs, 17%; from randomization CAD: 5.8 yrs, 29%; IAD: 5.1 yrs, 23%, HR (IAD/CAD) = 1.09 (95% CI 0.95, 1.24). No interaction with therapy was significant (p>0.25) except suggestion with disease extent (p=0.08): extensive disease HR=0.96 (95% CI 0.79, 1.15, p=0.64); minimal disease: HR=1.23 (95% CI 1.02, 1.48, p=0.035). PC was cause of death in 56% of CAD and 64% IAD pts. OSby race was not different (p=0.44). Conclusions: In HSM1PC, IAD is not proven to be noninferior to CAD. For extensive disease pts IAD was noninferior; however, IAD was statistically inferior in minimal disease pts suggesting that CAD is the preferred treatment in this group.

Dual inhibition of PI3K and mTOR inhibits autocrine and paracrine proliferative loops in PI3K/Akt/mTOR-addicted lymphomas

Primary effusion lymphoma (PEL) constitutes a subset of non-Hodgkin lymphoma whose incidence is highly increased in the context of HIV infection. Kaposi sarcoma–associated herpesvirus is the causative agent of PEL. The phosphatidylinositol 3-kinase (PI3K) signaling pathway plays a critical role in cell proliferation and survival, and this pathway is dysregulated in many different cancers, including PEL, which display activated PI3K, Akt, and mammalian target of rapamycin (mTOR) kinases. PELs rely heavily on PI3K/Akt/mTOR signaling, are dependent on autocrine and paracrine growth factors, and also have a poor prognosis with reported median survival times of less than 6 months. We compared different compounds that inhibit the PI3K/Akt/mTOR pathway in PEL. Although compounds that modulated activity of only a single pathway member inhibited PEL proliferation, the use of a novel compound, NVP-BEZ235, that dually inhibits both PI3K and mTOR kinases was significantly more efficacious in culture and in a PEL xenograft tumor model. NVP-BEZ235 was effective at low nanomolar concentrations and has oral bioavailability. We also report a novel mechanism for NVP-BEZ235 involving the suppression of multiple autocrine and paracrine growth factors required for lymphoma survival. Our data have broad applicability for the treatment of cytokine-dependent tumors with PI3K/mTOR dual inhibitors.