Heparin-collagen I bilayers stimulate FAK/ERK½ signaling via α2β1 integrin to support the growth and anti-inflammatory potency of mesenchymal stromal cells

Understanding mesenchymal stromal cells (MSCs) growth mechanisms in response to surface chemistries is essential to optimize culture methods for high-quality and robust cell yields in cell manufacturing applications. Heparin (HEP) and collagen 1 (COL) substrates have been reported to enhance cell adhesion, growth, viability, and secretory potential in MSCs. However, the biomolecular mechanisms underlying the benefits of combined HEP/COL substrates are unknown. This work used HEP/COL bilayered surfaces to investigate the role of integrin-HEP interactions in the advantages of MSC culture. The layer-by-layer approach (LbL) was used to create HEP/COL bilayers, which were made up of stacks of 8 and 9 layers that combined HEP and COL in an alternate arrangement. Surface spectroscopic investigations and laser scanning microscopy evaluations verified the biochemical fingerprint of each component and a total stacked bilayer thickness of roughly 150 nm. Cell growth and apoptosis in response to IC50 and IC75 levels of BTT-3033 and Cilengitide, α2β1 and αvβ3 integrin inhibitors respectively, were evaluated on HEP/COL coated surfaces using two bone marrow-derived MSC donors. While integrin activity did not affect cell growth rates, it significantly affected cell adhesion and apoptosis on HEP/COL surfaces. HEP-ending HEP/COL surfaces significantly increased FAK-ERK½ phosphorylation and endogenous cell COL deposition compared to COL, COL-ending HEP/COL and uncoated surfaces. BTT-3033 but not Cilengitide treatment markedly affected FAK-ERK½ activity levels on HEP-ending HEP/COL surfaces supporting a major role for α2β1 activity. BTT-3033 treatment on HEP-ending bilayers reduced MSC-mediated macrophage inhibitory activity and altered the cytokine profile of co-cultures. Overall, this study supports a novel role for HEP in regulating the survival and potency of MSCs via enhancing the α2β1-FAK-ERK½ signaling mechanism.

Substrate topographies modulate the secretory activity of human bone marrow mesenchymal stem cells

BACKGROUND

Mesenchymal stem cells (MSCs) secrete a diversity of factors with broad therapeutic potential, yet current culture methods limit potency outcomes. In this study, we used topographical cues on polystyrene films to investigate their impact on the secretory profile and potency of bone marrow-derived MSCs (hBM-MSCs). hBM-MSCs from four donors were cultured on topographic substrates depicting defined roughness, curvature, grooves and various levels of wettability.

METHODS

The topographical PS-based array was developed using razor printing, polishing and plasma treatment methods. hBM-MSCs from four donors were purchased from RoosterBio and used in co-culture with peripheral blood mononuclear cells (PBMCs) from Cell Applications Inc. in an immunopotency assay to measure immunosuppressive capacity. Cells were cultured on low serum (2%) for 24-48 h prior to analysis. Image-based analysis was used for cell quantification and morphology assessment. Metabolic activity of BM-hMSCs was measured as the mitochondrial oxygen consumption rate using an extracellular flux analyzer. Conditioned media samples of BM-hMSCs were used to quantify secreted factors, and the data were analyzed using R statistics. Enriched bioprocesses were identify using the Gene Ontology tool enrichGO from the clusterprofiler. One-way and two-way ANOVAs were carried out to identify significant changes between the conditions. Results were deemed statistically significant for combined P < 0.05 for at least three independent experiments.

RESULTS

Cell viability was not significantly affected in the topographical substrates, and cell elongation was enhanced at least twofold in microgrooves and surfaces with a low contact angle. Increased cell elongation correlated with a metabolic shift from oxidative phosphorylation to a glycolytic state which is indicative of a high-energy state. Differential protein expression and gene ontology analyses identified bioprocesses enriched across donors associated with immune modulation and tissue regeneration. The growth of peripheral blood mononuclear cells (PBMCs) was suppressed in hBM-MSCs co-cultures, confirming enhanced immunosuppressive potency. YAP/TAZ levels were found to be reduced on these topographies confirming a mechanosensing effect on cells and suggesting a potential role in the immunomodulatory function of hMSCs.

CONCLUSIONS

This work demonstrates the potential of topographical cues as a culture strategy to improve the secretory capacity and enrich for an immunomodulatory phenotype in hBM-MSCs.

PCL/PEO Polymer Membrane Prevents Biofouling in Wearable Detection Sensors

Technological advances in biosensing offer extraordinary opportunities to transfer technologies from a laboratory setting to clinical point-of-care applications. Recent developments in the field have focused on electrochemical and optical biosensing platforms. Unfortunately, these platforms offer relatively poor sensitivity for most of the clinically relevant targets that can be measured on the skin. In addition, the non-specific adsorption of biomolecules (biofouling) has proven to be a limiting factor compromising the longevity and performance of these detection systems. Research from our laboratory seeks to capitalize on analyte selective properties of biomaterials to achieve enhanced analyte adsorption, enrichment, and detection. Our goal is to develop a functional membrane integrated into a microfluidic sampling interface and an electrochemical sensing unit. The membrane was manufactured from a blend of Polycaprolactone (PCL) and Polyethylene oxide (PEO) through a solvent casting evaporation method. A microfluidic flow cell was developed with a micropore array that allows liquid to exit from all pores simultaneously, thereby imitating human perspiration. The electrochemical sensing unit consisted of planar gold electrodes for the monitoring of nonspecific adsorption of proteins utilizing Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). The solvent casting evaporation technique proved to be an effective method to produce membranes with the desired physical properties (surface properties and wettability profile) and a highly porous and interconnected structure. Permeability data from the membrane sandwiched in the flow cell showed excellent permeation and media transfer efficiency with uniform pore activation for both active and passive sweat rates. Biofouling experiments exhibited a decrease in the extent of biofouling of electrodes protected with the PCL/PEO membrane, corroborating the capacity of our material to mitigate the effects of biofouling.

Surface roughness modulates EGFR signaling and stemness of triple-negative breast cancer cells

Introduction: Cancer stem cells (CSC), a major culprit of drug-resistant phenotypes and tumor relapse, represent less than 2 % of the bulk of TNBC cells, making them difficult to isolate, study, and thus, limiting our understanding of the pathogenesis of the disease. Current methods for CSC enrichment, such as 3D spheroid culture, genetic modification, and stem cell conditioning, are time consuming, expensive, and unsuitable for high-throughput assays. One way to address these limitations is to use topographical stimuli to enhance CSC populations in planar culture. Physical cues in the breast tumor microenvironment can influence cell behavior through changes in the mechanical properties of the extracellular matrix (ECM). In this study, we used topographical cues on polystyrene films to investigate their effect on the proteome and stemness of standard TNBC cell lines. Methods: The topographical polystyrene-based array was generated using razor printing and polishing methods. Proteome data were analyzed and enriched bioprocesses were identified using R software. Stemness was assessed measuring CD44, CD24 and ALDH markers using flow cytometry, immunofluorescence, detection assays, and further validated with mammosphere assay. EGF/EGFR expression and activity was evaluated using enzyme-linked immunosorbent assay (ELISA), immunofluorescence and antibody membrane array. A dose-response assay was performed to further investigate the effect of surface topography on the sensitivity of cells to the EGFR inhibitor. Results: Surface roughness enriched the CSC population and modulated epidermal growth factor receptor (EGFR) signaling activity in TNBC cells. Enhanced proliferation of MDA-MB-468 cells in roughness correlated with upregulation of the epidermal growth factor (EGF) ligand, which in turn corresponded with a 3-fold increase in the expression of EGFR and a 42% increase in its phosphorylation compared to standard smooth culture surfaces. The results also demonstrated that phenotypic changes associated with topographical (roughness) stimuli significantly decreased the drug sensitivity to the EGFR inhibitor gefitinib. In addition, the proportion of CD44+/CD24-/ALDH+ was enhanced on surface roughness in both MDA-MB-231 and MDA-MB-468 cell lines. We also demonstrated that YAP/TAZ activation decreased in a roughness-dependent manner, confirming the mechanosensing effect of the topographies on the oncogenic activity of the cells. Discussion: Overall, this study demonstrates the potential of surface roughness as a culture strategy to influence oncogenic activity in TNBC cells and enrich CSC populations in planar cultures. Such a culture strategy may benefit high-throughput screening studies seeking to identify compounds with broader tumor efficacy.

IE-7925. Contribución de las vacunas antineumocócicas y la pandemia por SARS-CoV-2 en la evolución epidemiológica de la enfermedad neumocócica invasiva en España

Se evaluó la distribución de serotipos de la enfermedad neumocócica invasiva (ENI) por grupos de edad en España, así como el impacto de las vacunas antineumocócicas y el SARS-CoV-2.

Métodos

Estudio descriptivo que incluye 4.297 aislados clínicos de neumococo procedentes de niños y adultos con diagnóstico de ENI y durante el periodo 2019-2022.

Resultados

Se observó una disminución del 58% de los casos de ENI para todas las edades durante el primer año de pandemia por SARS-CoV-2 (2.435 casos en 2019 frente a 1.031 casos en 2020) con una reducción del 22% en 2021 (801 casos) frente a 2020. En los niños, la reducción fue del 53% en 2020 (239 casos en 2019 vs. 112 casos en 2020) con un aumento del 18% en 2021. El serotipo más frecuente en los 3 años fue el 24F. En adultos de 18-64 años y ≥ 65 años se observó una marcada reducción de casos de ENI durante el 2020 en comparación con 2019 (55% para 18-64 años y 61% para ≥ 65 años). Sin embargo, durante el año 2021, la disminución de ENI fue mucho más atenuada en comparación al 2020 (< 28% en ambos grupos de edad) y en lo que llevamos de 2022 han aumentado los casos con respecto al mismo periodo de 2021. En los adultos, el serotipo más frecuente fue el 8 seguido por el 3, representando entre los 2 hasta el 37% de todos los casos de ENI durante 2019-2021.

Conclusiones

La aparición del SARS-CoV-2 en España se asocia a una disminución de los casos de ENI con una recuperación parcial en los niños en el 2021 y en el 2022 tanto en la población pediátrica como adulta. Las nuevas vacunas conjugadas de 15 y 20 serotipos, incrementarán la fracción de la enfermedad prevenible por la vacunación frente a los serotipos circulantes.

Abstract 3075: EUS-guided biopsy of pancreatic mass lesions for the development of patient-derived organoids in Puerto Rico

Pancreatic cancer is an aggressive cancer that is diagnosed early in only 10% of cases and has a 5-year survival rate of less than 9%. The process in determining the optimal treatment for each patient is both long and tedious - and current strategies do not enable therapy optimization at the individual level. The incidence rate for pancreatic cancer in Puerto Rico between 2013 and 2017 was 8.2%, which is lower than the rate reported for non-Hispanic whites and blacks (16% and 12.9%, respectively). The causes for such health disparity are unknown but it is very likely associated with changes at the genomic and tissue microenvironment level at the sub-population level. To identify pathological markers in a more patient-specific manner, patient-derived models need to be integrated into studies of drug screening and efficacy. Patient-derived organoids (PDO) are becoming a potential model for diagnosis and the study of disease progression due to their ability to recreate the pathology of the tumor in the patients. Although several PDO studies have highlighted their potential for therapeutic applications, the ability to successfully culture and propagate these using standard methods has not been shown in samples collected from the Hispanic population. We assessed the feasibility of establishing PDOs from tissue specimens of a pancreatic mass lesion from Puerto Rican patients using standard methods for pancreatic organoids. A total of 9 samples were collected from endoscopic ultrasound fine-needle biopsies to examine the pathological features of the sample and the retention of the parental tumor characteristics in culture. All tissue specimens were cultured in Matrigel domes within 24 hours of extraction and organoid establishment was monitored for 7-8 days. All samples were positive for pancreatic adenocarcinoma but only around 50% of them were successfully cultured in Matrigel. High ATP levels were observed in tumor organoids after one week in culture which is indicative of a high cell viability. Examination of pathological markers indicated that all samples were negative for epidermal growth factor (EGFR), 5/6 were positive for smooth muscle actin (SMA), 4/6 were positive for Vimentin, and 1/6 were positive for CA 19.9. Absence of EGFR was unexpected as this marker is highly expressed and abundant in 40-70% of pancreatic cancers. Samples with high levels of SMA, a fibroblast marker, resulted in a higher organoid yield than samples with no SMA present. Overall, the data suggests that the presence of fibroblasts is supportive of organoid establishment in culture and that standard culture methods need to be optimized to increase organoid yields. Future work will seek to increase the sample size to test alternative propagation methods and examine drug sensitivity in patient-derived pancreas organoids of the Puerto Rican population.

Citation Format: Andrea S. Flores Perez, Janet Mendez Vega, Ana M. Reyes Ramos, Carlos Micames, Madeline Torres Lugo, Maribella Domenech. EUS-guided biopsy of pancreatic mass lesions for the development of patient-derived organoids in Puerto Rico [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3075.

Collagen I Fibrous Substrates Modulate the Proliferation and Secretome of Estrogen Receptor-Positive Breast Tumor Cells in a Hormone-Restricted Microenvironment

The fibril orientation of type I collagen has been shown to contribute to tumor invasion and metabolic changes. Yet, there is limited information about its impact on tumor cells' behavior in a restrictive growth environment. Restrictive growth environments are generated by the inhibition of a proliferation stimulus during therapy or as an inflammatory response to suppress tumor expansion. In this study, the impact of a type I collagen matrix orientation and fibrous architecture on cell proliferation and response to estrogen receptor (ER) therapy were examined using estrogen-dependent breast tumor cells (MCF-7 and T-47D) cultured in a hormone-restricted environment. The use of hormone-free culture media, as well as pharmacological inhibitors of ER, Tamoxifen, and Fulvestrant, were investigated as hormone restrictive conditions. Examination of cultures at 72 h showed that tumor cell proliferation was significantly stimulated (1.8-fold) in the absence of hormones on collagen fibrous substrates, but not on polycaprolactone fibrous substrates of equivalent orientation. ER inhibitors did not suppress cell proliferation on collagen fibrous substrates. The examination of reporter cells for ER signaling showed a lack of activity, thus confirming a shift toward an ER-independent proliferation mechanism. Examination of two selective inhibitors of α2β1 and α1β1 integrins showed that cell proliferation is suppressed in the presence of the α2β1 integrin inhibitor only, thereby indicating that the observed changes in tumor cell behavior are caused by a combination of integrin signaling and/or an intrinsic structural motif that is uniquely present in the collagen fibrils. Adjacent coculture studies on collagen substrates showed that tumor cells on collagen can stimulate the proliferation of cells on tissue culture plastic through soluble factors. The magnitude of this effect correlated with the increased surface anisotropy of the substrate. This sensing in fibril orientation was further supported by a differential expression pattern of secreted proteins that were identified on random and aligned orientation substrates. Overall, this study shows a new role for electrospun collagen I fibrous substrates by supporting a shift toward an ER-independent tumor cell proliferation mechanism in ER+ breast tumor cells.

Amphiphilic silicones to reduce the absorption of small hydrophobic molecules

Silicones (i.e. crosslinked poly(dimethylsiloxane), PDMS) are commonly used material for microfluidic device fabrication. Nonetheless, due to the uncontrollable absorption of small hydrophobic molecules (<1 kDa) into the bulk, its applicability to cell-based drug assays and sensing applications has been limited. Here, we demonstrate the use of substrates made of silicones bulk modified with a poly(ethylene oxide) silane amphiphile (PEO-SA) to reduce hydrophobic small molecule sequestration for cell-based assays. Modified silicone substrates were generated with concentrations of 2 wt.%, 9 wt.% and, 14 wt.% PEO-SA. Incorporation of PEO-SA into the silicone bulk was assessed by FTIR analysis in addition to water contact angle analysis to evaluate surface hydrophobicity. Cell toxicity, absorption of small hydrophobic drugs, and cell response to hydrophobic molecules were also evaluated. Results showed that the incorporation of the PEO-SA into the silicone led to a reduction in water contact angle from 114° to as low as 16° that was stable for at least three months. The modified silicones showed viability values above 85% for NIH-3T3, MCF7, MDA-MB-468, and MDA-MB-231 cell lines. A drug response assay using tamoxifen and the MCF7 cell line showed full recovery of cell toxicity response when exposed to PDMS modified with 9 wt.% or 14 wt.% PEO-SA compared to tissue culture plastic. Therefore, our study supports the use of PEO-SA at concentrations of 9 wt.% or higher for enhanced surface wettability and reduced absorption of small hydrophobic molecules in PDMS-based platforms.

Heparin/collagen surface coatings modulate the growth, secretome, and morphology of human mesenchymal stromal cell response to interferon-gamma

The therapeutic potential of human mesenchymal stromal cells (h-MSC) is dependent on the viability and secretory capacity of cells both modulated by the culture environment. Our previous studies introduced heparin and collagen I (HEP/COL) alternating stacked layers as a potential substrate to enhance the secretion of immunosuppressive factors of h-MSCs. Herein, we examined the impact of HEP/COL multilayers on the growth, morphology, and secretome of bone marrow and adipose-derived h-MSCs. The physicochemical properties and stability of the HEP/COL coatings were confirmed at 0 and 30 days. Cell growth was examined using cell culture media supplemented with 2 and 10% serum for 5 days. Results showed that HEP/COL multilayers supported h-MSC growth in 2% serum at levels equivalent to 10% serum. COL and HEP as single component coatings had limited impact on cell growth. Senescent studies performed over three sequential passages showed that HEP/COL multilayers did not impair the replicative capacity of h-MSCs. Examination of 27 cytokines showed significant enhancements in eight factors, including intracellular indoleamine 2, 3-dioxygenase, on HEP/COL multilayers when stimulated with interferon-gamma (IFN-γ). Image-based analysis of cell micrographs showed that serum influences h-MSC morphology; however, HEP-ended multilayers generated distinct morphological changes in response to IFN-γ, suggesting an optical detectable assessment of h-MSCs immunosuppressive potency. This study supports HEP/COL multilayers as a culture substrate for undifferentiated h-MSCs cultured in reduced serum conditions.

Polystyrene Topography Sticker Array for Cell-Based Assays

Cells can respond to different topographical cues in their natural microenvironment. Hence, scientists have employed microfabrication techniques and materials to generate culture substrates containing topographies for cell-based assays. However, one of the limitations of custom topographical platforms is the lack of adoption by the broad research community. These techniques and materials have high costs, require high technical expertise, and can leach components that may introduce artifacts. In this study, we developed an array of culture surfaces on polystyrene using razor printing and sanding methods to examine the impact of microscale topographies on cell behavior. The proposed technology consists of culture substrates of defined roughness, depth, and curvature on polystyrene films bound to the bottom of a culture well using double-sided medical-grade tape. Human monocytes and adult mesenchymal stem cells (hMSCs) were used as test beds to demonstrate the applicability of the array for cell-based assays. An increase in cell elongation and Arg-1 expression was detected in macrophages cultured in grooves and on rough substrates as compared to flat surfaces. Also, substrates with enhanced roughness stimulated the proliferation of hMSCs. This effect correlated with the secretion of proteins involved in cell proliferation and the downregulation of those associated with cell differentiation. Our results showed that the polystyrene topography sticker array supports cellular changes guided by microscale surface roughness and geometries. Consequently, microscale surface topographies on polished and razor-printed polystyrene films could leverage the endogenous mechanisms of cells to stimulate cellular changes at the functional level for cell-based assays.

Effects of Physical, Chemical, and Biological Stimulus on h-MSC Expansion and Their Functional Characteristics

Human adult mesenchymal stem or stromal cells (h-MSC) therapy has gained considerable attention due to the potential to treat or cure diseases given their immunosuppressive properties and tissue regeneration capabilities. Researchers have explored diverse strategies to promote high h-MSC production without losing functional characteristics or properties. Physical stimulus including stiffness, geometry, and topography, chemical stimulus, like varying the surface chemistry, and biochemical stimuli such as cytokines, hormones, small molecules, and herbal extracts have been studied but have yet to be translated to industrial manufacturing practice. In this review, we describe the role of those stimuli on h-MSC manufacturing, and how these stimuli positively promote h-MSC properties, impacting the cell manufacturing field for cell-based therapies. In addition, we discuss other process considerations such as bioreactor design, good manufacturing practice, and the importance of the cell donor and ethics factors for manufacturing potent h-MSC.

Mesenchymal Cells Support the Oncogenicity and Therapeutic Response of the Hedgehog Pathway in Triple-Negative Breast Cancer

The paracrine interaction between tumor cells and adjacent stroma has been associated with the oncogenic activity of the Hedgehog (Hh) pathway in triple-negative breast tumors. The present study developed a model of paracrine Hh signaling and examined the impact of mesenchymal cell sources and culture modalities in the oncogenicity of the Hh pathway in breast tumor cells. Studies consisted of tumor cell monocultures and co-cultures with cancer-associated and normal fibroblasts, tumor cells that undergo epithelial–mesenchymal transition (EMT), or adipose-derived mesenchymal stem cells (ADMSCs). Hh ligand and pathway inhibitors, GANT61 and NVP-LDE225 (NVP), were evaluated in both cell cultures and a mouse xenograft model. Results in monocultures show that tumor cell viability and Hh transcriptional activity were not affected by Hh inhibitors. In co-cultures, down-regulation of GLI1, SMO, and PTCH1 in the stroma correlated with reduced tumor growth rates in xenografted tumors and cell cultures, confirming a paracrine interaction. Fibroblasts and EMT cells supported Hh transcriptional activity and enhanced tumor cell growth. Mixed and adjacent culture modalities indicate that tumor growth is supported via fibroblast-secreted soluble factors, whereas enriched tumor stemness requires close proximity between tumor and fibroblasts. Overall this study provides a tumor–mesenchymal model of Hh signaling and highlights the therapeutic value of mesenchymal cells in the oncogenic activity of the Hh pathway.

P14.58 Extending adjuvant temozolomide longer than six cycles doesn’t add any benefit to glioblastoma patients according to the randomized GEINO-014 TRIAL

BACKGROUND

Standard treatment of glioblastoma (GBM) is focal radiation with concomitant and adjuvant temozolomide (TMZ) for 6 cycles. The GEINO-14-01 trial (NCT02209948) investigated the role of extending adjuvant TMZ to 12 cycles in a randomized multicenter study.

MATERIAL AND METHODS

Between Aug/2014 and Nov/2018, 166 patients (p) were screened and 159 randomized to extend (80p) or not (79p) TMZ treatment to 12 cycles after proving stable disease in the MRI performed before inclusion. The trial was stratified by MGMT status and presence or absence of residual disease (defined as a residual enhancement larger than 1cm on the MRI). The primary endpoint was differences in 6monthsPFS, secondary endpoints were differences in PFS, OS, toxicity, between arms and per stratification factors.

RESULTS

Median age was 60.4 (range 29–83), 97p (61%) were methylated and 83 p (52.2%) were reported with residual disease. Median (m) PFS was 7.9 months (95%CI: 6.1–9.8) and mOS: 20.9 (95%CI: 17.6–24.1). A methylated status was a factor of better PFS (HR=0.29, 95% CI 0.46–0.95; p=0.029) and better OS (HR= 0.43: 95% CI 0.28–0.66; p=0.000) as well as the absence of residual disease (PFS: HR = 0.84: 95% CI =0.71–1.01; p=0.068; OS: HR=0.77, 95%CI 0.63–0.96; p=0.019). We didn’t find any difference in PFS (HR=1.02, 95%CI 0.85–1.21; p=0.82), or OS (HR=0.90; 0.73–1.11; p=0.34) on extending treatment with temozolomide longer than 6 cycles.

CONCLUSION

There is no benefit of continuing TMZ treatment for more than 6 cycles in the adjuvant treatment of glioblastoma. Final data will be presented at the congress. Supported by a Grant of the ISCIII: PI13/01751

Abstract 1984: Anisotropy of collagen I matrix influences therapeutic response and secretome of Luminal A cells

High degree of collagen I fiber orientation has been associated with guided tumor cell invasion, but little is known about its impact in therapeutic response. Anisotropic substrates have been shown to influence the phenotype of stem cells which suggests that it can influence tumor cell behavior beyond cell migration. We hypothesized that the anisotropy of collagen I matrix impacts therapeutic response by modulating the secretome of breast cancer cells and this effect is mediated by integrin signaling. To test our hypothesis, the cell secretome, response to hormone ablation therapy and integrin inhibitors were evaluated in breast tumor cells cultured in collagen type 1 substrates of defined orientation. The orientation of electrospun collagen I fibrils was regulated by adjusting the syringe flow rate and collector velocity to obtain random (&lt;70%) or aligned (&gt;80%) oriented fibrils. Average porosity (45± 3.4 %), matrix stiffness (0.8 ±0.24 MPa) and fiber diameter (1.6 ± 0.86μm) were kept constant across collagen substrates. Estrogen-dependent Luminal A cells (MCF-7 and T-47D) cells were cultured on collagen substrates in a hormone-deprived environment for 3-6 days. Polycaprolactone (PCL) fibrous substrates of aligned and random orientation were used as negative fibrous controls for integrin signaling. Evaluation of cell growth showed that a fibrillar structure in combination with a high degree of fibril orientation significantly increased cell proliferation (&gt;75%) as compared to gelatin-coated tissue culture plastic (TCP). Collagen fibers significantly supported hormone-independent tumor growth at levels equivalent to or above those observed in the estrogen-treated control. Increased proliferation levels were supported on collagen fibrous substrates treated with Tamoxifen and Fulvestrant, and this effect was enhanced in aligned collagen I. Inhibition of α2β1 integrin resulted in enhanced proliferation rates in random fibers and suppression of cell growth in aligned fibers. PCL aligned substrates where not sufficient to support hormone-independent cell growth. MCF-7 cells on collagen substrates significantly stimulated the growth (&gt;7 fold) of adjacent cells on TCP in a dose-response manner as follows: aligned &gt; random &gt; gelatin. Expression levels of 1000 factors were quantified in conditioned medium to identify differences in the secretome signatures associated with cell-matrix signaling. MCF-7 cells cultured on collagen fibrous substrates displayed secretome signatures that were different across all substrates. Fourteen factors were identified to be upregulated in fibrous substrates by more than ten folds including apoptotic regulators RalA and BCL-2. Our results show for the first time the influence of collagen I fibril orientation in supporting hormone-independent growth and as a novel regulator therapeutic response in luminal A cells.

Citation Format: Ana M. Reyes, Jorge Almodovar, Elaine Alarid, Maribella Domenech. Anisotropy of collagen I matrix influences therapeutic response and secretome of Luminal A cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1984.

Open multi-culture platform for simple and flexible study of multi-cell type interactions

The study of multi-cell-type (MCT) interactions has the potential to significantly impact our understanding of tissue and disease biology. Such studies require innovative culture tools for unraveling the contributions of each cell type. Micro- and macro-scale platforms for MCT culture each have different advantages and disadvantages owing to their widely different capabilities, availability, and ease-of-use. However, as evidenced in the literature, there are very few examples of MCT studies and culture platforms, suggesting both biological and technical barriers. We have developed an open multi-culture platform to promote more rapid progress by integrating advantages of both micro- and macro-scale culture devices. The proposed open multi-culture platform addresses technical barriers by allowing easy customization, independent control of basic physical culture parameters, and incorporation of multiple culture modalities (e.g., 2D, 3D, transwell, and spheroid). The design also permits the user to obtain independent endpoints for each culture region. We demonstrate use of the platform in two example studies where we evaluated how cell ratio and cell types influence the response of triple negative breast cancer cells to heat damage and Hedgehog signaling. We also show that the platform can improve soluble factor transport between cell types compared to compartmentalized macro- and micro-scale alternatives. Last, we examine current and future challenges of the platform. We envision simple, yet flexible and customizable, platforms such as this will be important for advancing in vitro study of tissue and tumor biology.

Hedgehog-mesenchyme gene signature identifies bi-modal prognosis in luminal and basal breast cancer sub-types

Hedgehog signaling (Hh) has been shown to be hyper-activated in several cancers. However, active Hh signaling can promote or inhibit tumor growth; thus identification of markers beyond main canonical Hh target genes is needed to improve patient selection and clinical outcome in response to Hh inhibitors. Cancer-associated fibroblasts (CAFs) have been linked with tumor progression and beneficial response to Hh inhibitors. Thus, we hypothesized that genes associated with Hh-activated CAFs can be used for stratification of tumors that will benefit from Hh inhibitors. In this work, we evaluated a 15-gene fingerprint that combines Hh and mesenchymal genes associated with CAF phenotype to profile breast cancer sub-types based on gene expression patterns among clustered groups. About 3800 cancer samples were evaluated using random forest models and linear discriminant analysis to sort breast cancer by subtypes and therapeutic approach. The results showed that the Hh-mesenchyme gene fingerprint has a highly sensitive and differential expression pattern among basal and luminal A sub-groups. Basal samples with high levels of Hh target genes had better prognosis than luminal A samples. Luminal A samples with a tendency towards Hh signaling suppression had higher overall and disease-free survival rates particularly if deprived of hormone therapy. Hh transcriptional repressor GLI3 and signaling activator SMO were the top 2 genes for discriminating among samples with active Hh signaling in human breast cancer subtypes and Hh-inhibitor resistant tumors. Caveolin-1 (CAV1), a gene with low expression in CAFs, shows strong correlation with active Hh signaling and discrimination among survival curves in luminal A patients with active or inactive Hh signaling. Our data suggest that CAV1 is an important gene for monitoring Hh inhibition in tumors and support further stratification by hormone therapy status prior to use of Hh inhibitors.

Abstract 174: Collagen fiber orientation influences tumor cell growth and Hedgehog signaling in the breast tumor microenvironment

Collagen matrix architecture is an important player in tumor transition to therapeutic resistance. Several studies have shown that high level of fiber orientation and density of collagen type I matrix enhances tumor cell invasion, decrease drug response and influence tumor metabolism, but the mechanisms of action that support transition to therapeutic resistance are not fully understood. We developed a 3D culture platform to evaluate the effects of collagen matrix architecture in the sensitivity of tumor and stromal cells to tumor promoting ligands and pharmacological inhibitors. Estrogen (E2) and Hedgehog (Hh) signaling pathways were selected for evaluation due to their relevance in breast cancer prognosis and tumor progression. In this 3D culture platform, electrospun collagen fiber sheets of random or aligned orientation are bound to double-sided medical grade tape to generate collagen fiber stickers. Automated cutting plotter allows razor-printing for precisely cutting shapes from collagen fiber sticker sheets. Round shapes were applied like a sticker to the bottom of culture well plates prior to cell seeding. The percentage of matrix porosity fiber orientation and diameter was quantified by Scanning Electron Microscopy (SEM) and Image J analysis. For estrogen signaling studies, MCF-7 cells were seeded in collagen fibers of random or aligned orientation using hormone free-culture conditions. Cells were treated +/- E2 (10nM) ligand and +/- estrogen receptor signaling inhibitors (Fulvestrant and Tamoxifen). Tumor cell proliferation was quantified at 48hrs via Image Cytometry. For Hh signaling studies, expression levels of GLI1, PTCH1 and SMO Hh target genes were monitored in triple negative breast cancer (MDA-MB-231 and MDA-MB-468) and mesenchymal cells. Cells were seeded on collagen fibers and treated with sonic hedgehog ligand for 24hrs. Tumor and mesenchymal cells were harvest for viability and qRT-PCR analysis respectively. Evaluation of cell growth in MCF-7 cultures shows that a fibrillar structure of collagen matrix in combination with high degree of fiber orientation can significantly increase cell proliferation as compared to gelatin or tissue culture plastic substrates. Collagen fibers significantly supported hormone-independent tumor growth at similar levels to those observed in E2 treatment. Increased proliferation levels were maintained in ER inhibition groups particularly when cultured in aligned collagen fibers. In Hh signaling studies, overexpression of GLI1 and SMO genes were observed for collagen fibers matrixes as compared to gelatin and tissue culture plastic. Overall our results show for the first time that collagen fiber architecture can promote hormone-independent growth dependence in breast cancer cells and activation of hedgehog signaling in tumor and mesenchymal cells.

Citation Format: Ana M. Reyes, Jorge Almodovar, Maribella Domenech. Collagen fiber orientation influences tumor cell growth and Hedgehog signaling in the breast tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 174.

Razor-printed sticker microdevices for cell-based applications

Tape-based razor-printing is a flexible and affordable ultra-rapid prototyping approach for microscale device fabrication. However, integration of this prototyping approach into cell-based assay development has been limited to proof of principle demonstrations. This is in large part due to lack of an established or well-characterized option for biocompatible adhesive tape. Without such an option, integration of these areas will remain unexplored. Therefore, to address this critical hurdle, we characterized microscale devices made using a potentially biocompatible double-sided adhesive, ARCare 90106. We validated tape-based device performance against 96-well plates and PDMS microdevices with respect to cell viability, hydrophobic small molecule sequestration, the potential for leaching compounds, use in fluorescence microscopy, and outgassing (bubble formation). Results supported the tape as a promising tool for future cell-based assay development. Therefore, we subsequently demonstrated specific strengths enabled by the ultra-rapid (<1 h per prototype) and affordable (∼$1200 cutting plotter, <$0.05 per prototype) approach. Specifically, data demonstrate the ability to integrate disparate materials for advanced sticker-device functionality such as bonding of polystyrene devices to glass substrates for microscopy applications, inclusion of membranes, and incorporation of different electrospun biomaterials into a single device. Likewise, the approach allowed rapid adoption by uninitiated users. Overall, this study provides a necessary and unique contribution to the largely separate fields of tape-based razor-printing and cell-based microscale assay development by addressing a critical barrier to widespread integration and adoption while also demonstrating the potential for new and future applications.

HIF pathway and c-Myc as biomarkers for response to sunitinib in metastatic clear-cell renal cell carcinoma

BACKGROUND

Clear-cell renal cell carcinoma (ccRCC) is a heterogeneous disease with a different clinical behavior and response to targeted therapies. Differences in hypoxia-inducible factor (HIF) expression have been used to classify von Hippel-Lindau gene (VHL)-deficient ccRCC tumors. c-Myc may be driving proliferation in HIF-2α-expressing tumors in a growth factor-independent manner.

OBJECTIVE

To explore the HIF-1α, HIF-2α and c-Myc baseline expression as potential predictors of sunitinib outcome as well as the effectiveness and safety with sunitinib in patients with metastatic ccRCC in routine clinical practice.

METHODS

This was an observational and prospective study involving 10 Spanish hospitals. Formalin-fixed, paraffin-embedded primary tumor samples from metastatic ccRCC patients who received sunitinib as first-line treatment were analyzed. Association between biomarker expression and sunitinib treatment outcomes was evaluated. Kaplan-Meier method was applied to measure progression-free survival (PFS) and overall survival.

RESULTS

Eighty-one patients were included: median PFS was 10.8 months (95% CI: 7.4-13.5 months), median overall survival was 21.8 months (95% CI: 14.7-29.8 months) and objective response rate was 40.7%, with 7.4% of patients achieving a complete response. Molecular marker staining was performed in the 69 available tumor samples. Significant association with lower PFS was identified for double c-Myc/HIF-2α-positive staining tumors (median 4.3 vs 11.5 months, hazard ratio =2.64, 95% CI: 1.03-6.80, P=0.036). A trend toward a lower PFS was found in positive c-Myc tumors (median 5.9 vs 10.9 months, P=0.263). HIF-1α and HIF-2α expression levels were not associated with clinical outcome.

CONCLUSION

These preliminary results suggest that predictive subgroups might be defined based on biomarkers such as c-Myc/HIF-2α. Further validation with more patients will be needed in order to confirm it. Outcomes with sunitinib in metastatic ccRCC in daily clinical practice resemble those obtained in clinical trials.

Abstract 1334: Mesenchymal cell sub-populations selectively modulate paracrine hedgehog signaling in triple negative breast cancer

Recent studies correlate Hedgehog (Hh) signaling with reduced survival rates in triple negative breast cancer (TNBC) patients. Activation of hedgehog signaling in the adjacent mesenchyme has been shown to promote tumor growth and it is a poor prognosis factor for TNBC. We developed a novel tumor-mesenchymal in vitro model of hedgehog signaling in TNBC to evaluate the role of mesenchymal cell sub-populations in the proliferative potential and stem cell markers of breast cancer cells using a custom designed multiwell array. As a source of mesenchymal cell sub-populations we evaluated myofibroblasts, mesenchymal stem cells derived from bone marrow or adipose tissue and tumor cells that undergo epithelial-mesenchymal transition (EMT). Tumor cells were culture with 1 or 2 mesenchymal cell sub-populations in adjacent compartments +/- SHH ligand for 72-96hrs. Active Hh signaling was confirmed by up-regulation of main Hh target genes (e.g. Gli1, Patch1). Paracrine Hh signaling only in bone marrow-derived mesenchymal stem cell and EMT significantly increased proliferation (10-15%) of TNBC and normal breast cancer cell lines. Addition of adipose-derived mesenchymal stem cells or pharmacological Hh inhibitors (Cyclopamine and Gant61) partially abolished tumor growth indicating that other non-canonical signals are involve in paracrine Hh-driven tumors. Cancer stem cell markers were selectively modulated in co-cultures. Our results suggest that paracrine Hh signaling-driven by bone marrow and EMT mesenchymal are potential therapeutic targets to treating TNBC.

Citation Format: Karla P. Ramos, Maribella Domenech. Mesenchymal cell sub-populations selectively modulate paracrine hedgehog signaling in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1334. doi:10.1158/1538-7445.AM2017-1334

Abstract P4-21-32: Treatment of early HER2-positive breast cancer in trastuzumab era in everyday clinical practice: An overview after 10 years of its approval

Introduction: The addition of Trastuzumab(T) to chemotherapy (CT) revolutionized HER2-positive breast cancer(BC) and changed its natural history. We reviewed the efficacy of T outside clinical trials in a cancer comprehensive center.

Methods: Ambiespective and descriptive study was conducted in Catalan Institute of Oncology (ICO-Barcelona). Estimates of progression-free survival (PFS) and overall survival (OS) were obtained with the Kaplan-Meier method and compared with LogRank test. The association of clinic-pathological variables and outcome was studied by χ2and Cox proportional hazard analysis.

Results: 430 consecutive early HER2-positive BC patients (pts) were treated with adjuvant/neoadjuvant T and CT from Jan 2005 to Dec 2012. Pt basal characteristics are reported in Table 1. Neoadjuvant treatment was administrated in 230pts (54%) and in 200 (46%) in adjuvancy. Pathological complete response (pCR) in breast and nodes (ypT0/isypN0) was achieved in 48% of pts, with higher rates in hormone receptor (HR)-negative pts (62 vs 37% p=0.0005). Median duration of T: 10.6 months (m). 28%pts treated with neoadjuvant T+CT who achieved a pCR did not receive adjuvant T. Treatment discontinuation: 38pts (8.8%): 27pts due to cardiac toxicity and 4 relapsed during adjuvant T. In 87%pts, neoadjuvant CT was based on anthracyclines(A) and taxanes. Adjuvant CT: A and taxanes in 57.4%; 14%pts FAC, 15.4% A-CMF and 12% TCH. At a median follow-up of 70m (3-135), 44pts (10.4%) had relapsed: 33pts with distant M1, 9pts with only loco-regional disease and 2pts contralateral HER2-positive BC. M1 location: 46% visceral, 34% bone/lymph nodes and 20% in central nervous system (CNS). PFS was 23.4m(0-88); median OS was not reached; estimated 10 years-OS was 86.5%. Pts treated with A and taxanes had a significantly better OS compared to those treated with other CT (113 vs 98m, p= 0.009). Kaplan-Meier curve showed numerically higher relapses at 10 years in HR-positive pts (83 vs 90% p=0.8). Pts with pCR had significantly better OS (113 vs 104m, p=0.006). Pts with CNS-metastases had a significantly worse OS (13 vs 26m,p=0,02) and those with HR-negative (49 vs 24m, p= 0.033).

Conclusion: In everyday clinical practice, recurrences after adjuvant/neoadjuvant trastuzumab in HER2-positive BC were less than described in the T-pivotals trials, with 10% of recurrences at a median of FU of 70m. In our series, estimated 10 years-OS was 86.5%. Pts treated with A and taxanes had a significantly better OS as well as those pts who achieved a pCR. On the contrary, pts with CNS M1 and those with HR-negative had worse prognosis.

Table 1Median age51.9y (27-83)Stage I/II/III106 (25%)/ 226 (52%)/ 97 (23%)HR Positive/ Negative249 (58%)/181 (42%)

Citation Format: Ortega A, Domenech M, Falo C, Gil M, Stradella A, Fernandez A, Morilla I, Villanueva R, Castany R, Vazquez S, Molina K, Bergamino M, Navarro V, Pernas S. Treatment of early HER2-positive breast cancer in trastuzumab era in everyday clinical practice: An overview after 10 years of its approval [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-21-32.

Abstract B02: Open multi-microwell array for the study of paracrine signaling in tumors

The development and progression of tumors are modulated by the interaction among multiple cell types present at the tumor adjacent tissue. Few in vitro cell culture platforms allow one to test multi-cellular interactions and those suitable require high numbers of cells limiting studies to cell lines and excluding heterogeneous patient samples, and fail to provide tunable discrete adjacent compartments for the retrieval of independent cell population readouts. Mixing of cells in adjacent compartments and cell sorting after mixed culture represent a costly and time consuming procedure that often results is lost, reduction and/or damage of the recovered sample. To overcome some of these limitations we have developed an open multi-microwell array that enables co-culture of up to 4 cell populations in discrete adjacent wells using either 2- or 3-dimension culture conditions. The circular microwells are made of poly-dimethyl siloxane (PDMS) and placed on top of glass or tissue culture plastic. The open-well format allows cells and culture media to be manually loaded and replaced using a pipette independently of passive pumping method, and without the need of vacuum-assisted filling or syringe pumps. The microwell array is aligned to a 96well plate format for automated fluorescent readouts. The cell culture surface area of each microwell is 5.7mm2 (5ul) and can accommodate 5,000-10,000 cells but the design of each microwell can be scale-down to accommodate smaller cell samples. The adjacent microwells are contained within an outer-ring of 8mm diameter and 750um height. After cell seeding, adjacent compartments can be connected by dispensing a volume of 30-40ul inside the outer ring. A model of tumor-mesenchyme paracrine Hedgehog signaling was developed and characterized to show the feasibility of this array for multi-cell soluble factor signaling studies. Activation of Hedgehog (Hh) signaling in the mesenchyme promotes proliferation of tumor cells via secreted factors. As a source of mesenchymal cell sub-types we evaluated TGF-b treated fibroblasts and tumor epithelial cells that undergo epithelial-mesenchymal transition. Myofibroblast phenotype was confirmed based on overexpression of smooth muscle actin, vimentin and fibroblast activating protein, and reduce levels of caveolin-1. Active Hh signaling and pharmacological inhibition with cyclopamine were confirmed by up- and down- regulation of canonical Hh target genes Gli1 and Patch1. Active hedgehog signaling and cell viability was maintained over 5-7days 2-dimensional and collagen type I embedded mesenchymal cells. Breast-derived human epithelial and mesenchymal cells co-cultured in microwells and transwells showed similar increase in tumor cell proliferation rates but with a reduction of 80% or more in the total cells needed compared to transwells. Flow cytometer read-outs of proliferation and tumor cell distribution of CD44/CD24 cell surface receptors were similar among transwells and microwells. Adjacent culture of mouse derived fibroblasts (NIH-3T3) and human tumor cells showed recovery of genomic sample without cell-population mixing using primers for specific for human and mouse GAPDH. Doubling of the number of microwells with mesenchymal cells modulated the observed proliferative effect in tumor cells suggesting that mesenchymal cell ratios modulate tumor response to paracrine Hh signaling. This observation could not be replicated in macro-scale platforms as active Hh signaling in the mesenchyme is achieved via cell growth arrest using a combination of low serum and cell confluence. The open multi-microwell array represents a new user-friendly multi-culture microscale array with optimized capabilities for the study of paracrine signaling among discrete cell populations compared to macroscale culture technology.

Citation Format: Karla P. Ramos, Fernando Boria, Maribella Domenech. Open multi-microwell array for the study of paracrine signaling in tumors. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr B02.

Tissue Engineering Strategies for Myocardial Regeneration: Acellular Versus Cellular Scaffolds?

Heart disease remains one of the leading causes of death in industrialized nations with myocardial infarction (MI) contributing to at least one fifth of the reported deaths. The hypoxic environment eventually leads to cellular death and scar tissue formation. The scar tissue that forms is not mechanically functional and often leads to myocardial remodeling and eventual heart failure. Tissue engineering and regenerative medicine principles provide an alternative approach to restoring myocardial function by designing constructs that will restore the mechanical function of the heart. In this review, we will describe the cellular events that take place after an MI and describe current treatments. We will also describe how biomaterials, alone or in combination with a cellular component, have been used to engineer suitable myocardium replacement constructs and how new advanced culture systems will be required to achieve clinical success.

Abstract B05: Mesenchymal-driven hedgehog signaling drives tumor cell growth and is a potential new target for triple-negative breast cancer

Triple negative breast cancer (TNBC) is a clinical therapeutic challenge due to the lack of receptors for estrogen, progesterone, and human epidermal growth factor receptor 2 which limits treatment options to chemotherapy and radiation. With current standard therapy less than 30% will survive the 5-year remission rate, especially Hispanic and African-American women where TNBC is more frequent and has the lowest (&lt;14%) 5-year survival rates. Recent studies indicate that Hedgehog (Hh) signaling is active and correlates with reduced survival rates in TNBC patients. However, the role of the Hh signaling in the breast tumor microenvironment is not well understood. A main cellular mediator of Hh signaling is the adjacent mesenchyme which promotes tumor growth via a paracrine interaction, but which is also highly heterogeneous. As mesenchymal sub-types have been associated to specific pharmacological therapies, understanding of the mechanisms in mesenchymal-driven tumors is necessary for combinatorial pharmacological treatments that can increase survival rates and eliminate tumor relapse in patients. We developed a tumor-mesenchymal in vitro model to evaluate the role of mesenchymal cell sub-types from different sources in the proliferative potential and stem cell markers of breast cancer cells using a custom designed multiwell array. Cells were culture in adjacent compartments and active Hh signaling was confirmed by up-regulation of canonical Hh target genes Gli1, Patch1 and SMO. As a source of mesenchymal cell sub-types we evaluated TGF-β treated fibroblasts, cancer- associated and normal breast primary fibroblasts, and tumor epithelial cells that undergo epithelial-mesenchymal transition (EMT). Paracrine Hh signaling significantly increased proliferation (5-10%) of tumor cells after 72-96hrs in co-culture. Cells that undergo EMT promoted cell growth at higher rates than myofibroblasts. SHH treatment alone (without TGF-β pre-treatment) had an inhibitory effect in the proliferation rates of the adjacent epithelium compartment. Observed increase in tumor cell proliferation was abolished when treated with the Hh signaling inhibitor cyclopamine. Stem cell surface markers CD44+CD24- remained unchanged but a significant increase was observed in the proliferating CD44+/CD24+ sub-population. Similar results were observed in normal human breast cells suggesting that activation of Hh signaling in the mesenchyme is sufficient to promote cell growth in the epithelium. Computational analysis of a panel of genes associated to Hh signaling in breast cancer patients (&gt;500 samples) show a strong correlation among TNBC patients and mesenchymal-driven Hh signaling in &gt;80% of samples. We evaluated the distribution of mesenchymal cell-sub-types and stem cells among the sub-set of basal TNBC samples (82 samples). Gene markers associated to myofibroblasts, EMT, mesenchymal stem cell and cancer stem cell were found in samples with active Hh signaling and co-expressed in groups of two or more which represented the 45.6% of the total samples. The most abundant cell sub-type were cancer stem cells with 43% of the total samples and alone by itself in 13.9% of samples. Together, these results indicate that the Hh-pathway and adjacent tumor microenvironment are key players in the progression of TNBC. Mesenchymal cell component can modulate tumor growth behavior induced by Hh signaling and is a potential new clinical target for TNBC.

Citation Format: Maribella Domenech, Karla P. Ramos, Wandaliz Torres, Fernando Boria. Mesenchymal-driven hedgehog signaling drives tumor cell growth and is a potential new target for triple-negative breast cancer. [abstract]. In: Proceedings of the AACR Special Conference: Developmental Biology and Cancer; Nov 30-Dec 3, 2015; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(4_Suppl):Abstract nr B05.

Phosphodiesterase 4D inhibitors limit prostate cancer growth potential

Phosphodiesterase 4D (PDE4D) has recently been implicated as a proliferation-promoting factor in prostate cancer and is overexpressed in human prostate carcinoma. However, the effects of PDE4D inhibition using pharmacologic inhibitors have not been examined in prostate cancer. These studies examined the effects of selective PDE4D inhibitors, NVP-ABE171 and cilomilast, as anti-prostate cancer therapies in both in vitro and in vivo models. The effects of PDE4D inhibitors on pathways that are critical in prostate cancer and/or downstream of cyclic AMP (cAMP) were examined. Both NVP-ABE171 and cilomilast decreased cell growth. In vitro, PDE4D inhibitors lead to decreased signaling of the sonic hedgehog (SHH), androgen receptor (AR), and MAPK pathways, but growth inhibition was best correlated to the SHH pathway. PDE4D inhibition also reduced proliferation of epithelial cells induced by paracrine signaling from cocultured stromal cells that had activated hedgehog signaling. In addition, PDE4D inhibitors decreased the weight of the prostate in wild-type mice. Prostate cancer xenografts grown in nude mice that were treated with cilomilast or NVP-ABE171 had decreased wet weight and increased apoptosis compared with vehicle-treated controls. These studies suggest the pharmacologic inhibition of PDE4D using small-molecule inhibitors is an effective option for prostate cancer therapy.

IMPLICATIONS

PDE4D inhibitors decrease the growth of prostate cancer cells in vivo and in vitro, and PDE4D inhibition has therapeutic potential in prostate cancer.