A novel chemo-phenotypic method identifies mixtures of salpn, vitamin D3, and pesticides involved in the development of colorectal and pancreatic cancer

Environmental chemical (EC) exposures and our interactions with them has significantly increased in the recent decades. Toxicity associated biological characterization of these chemicals is challenging and inefficient, even with available high-throughput technologies. In this report, we describe a novel computational method for characterizing toxicity, associated biological perturbations and disease outcome, called the Chemo-Phenotypic Based Toxicity Measurement (CPTM). CPTM is used to quantify the EC "toxicity score" (Z_ts), which serves as a holistic metric of potential toxicity and disease outcome. CPTM quantitative toxicity is the measure of chemical features, biological phenotypic effects, and toxicokinetic properties of the ECs. For proof-of-concept, we subject ECs obtained from the Environmental Protection Agency's (EPA) database to the CPTM. We validated the CPTM toxicity predictions by correlating 'Z_ts' scores with known toxicity effects. We also confirmed the CPTM predictions with in-vitro, and in-vivo experiments. In in-vitro and zebrafish models, we showed that, mixtures of the motor oil and food additive 'Salpn' with endogenous nuclear receptor ligands such as Vitamin D3, dysregulated the nuclear receptors and key transcription pathways involved in Colorectal Cancer. Further, in a human patient derived cell organoid model, we found that a mixture of the widely used pesticides 'Tetramethrin' and 'Fenpropathrin' significantly impacts the population of patient derived pancreatic cancer cells and 3D organoid models to support rapid PDAC disease progression. The CPTM method is, to our knowledge, the first comprehensive toxico-physicochemical, and phenotypic bionetwork-based platform for efficient high-throughput screening of environmental chemical toxicity, mechanisms of action, and connection to disease outcomes.

Paramagnetic Mn8Fe4-co-Polystyrene Nanobeads as a Potential T1-T2 Multimodal Magnetic Resonance Imaging Contrast Agent with In Vivo Studies

In developing a cluster-nanocarrier design, as a magnetic resonance imaging contrast agent, we have investigated the enhanced relaxivity of a manganese and iron-oxo cluster grafted within a porous polystyrene nanobead with increased relaxivity due to a higher surface area. The synthesis of the cluster-nanocarrier for the cluster Mn8Fe4O12(O2CC6H4CH═CH2)16(H2O)4, cross-linked with polystyrene (the nanocarrier), under miniemulsion conditions is described. By including a branched hydrophobe, iso-octane, the resulting nanobeads are porous and ∼70 nm in diameter. The increased surface area of the nanobeads compared to nonporous nanobeads leads to an enhancement in relaxivity; r1 increases from 3.8 to 5.2 ± 0.1 mM-1 s-1, and r2 increases from 11.9 to 50.1 ± 4.8 mM-1 s-1, at 9.4 teslas, strengthening the potential for T1 and T2 imaging. Several metrics were used to assess stability, and the porosity produced no reduction in metal stability. Synchrotron X-ray fluorescence microscopy was used to demonstrate that the nanobeads remain intact in vivo. In depth, physicochemical characteristics were determined, including extensive pharmacokinetics, in vivo imaging, and systemic biodistribution analysis.

Optical and magnetic resonance imaging approaches for investigating the tumour microenvironment: state-of-the-art review and future trends

The tumour microenvironment (TME) strongly influences tumorigenesis and metastasis. Two of the most characterized properties of the TME are acidosis and hypoxia, both of which are considered hallmarks of tumours as well as critical factors in response to anticancer treatments. Currently, various imaging approaches exist to measure acidosis and hypoxia in the TME, including magnetic resonance imaging (MRI), positron emission tomography and optical imaging. In this review, we will focus on the latest fluorescent-based methods for optical sensing of cell metabolism and MRI as diagnostic imaging tools applied both in vitro and in vivo. The primary emphasis will be on describing the current and future uses of systems that can measure intra- and extra-cellular pH and oxygen changes at high spatial and temporal resolution. In addition, the suitability of these approaches for mapping tumour heterogeneity, and assessing response or failure to therapeutics will also be covered.

Predicting new drug indications for prostate cancer: The integration of an in silico proteochemometric network pharmacology platform with patient-derived primary prostate cells

BACKGROUND

Drug repurposing enables the discovery of potential cancer treatments using publically available data from over 4000 published Food and Drug Administration approved and experimental drugs. However, the ability to effectively evaluate the drug's efficacy remains a challenge. Impediments to broad applicability include inaccuracies in many of the computational drug-target algorithms and a lack of clinically relevant biologic modeling systems to validate the computational data for subsequent translation.

METHODS

We have integrated our computational proteochemometric systems network pharmacology platform, DrugGenEx-Net, with primary, continuous cultures of conditionally reprogrammed (CR) normal and prostate cancer (PCa) cells derived from treatment-naive patients with primary PCa.

RESULTS

Using the transcriptomic data from two matched pairs of benign and tumor-derived CR cells, we constructed drug networks to describe the biological perturbation associated with each prostate cell subtype at multiple levels of biological action. We prioritized the drugs by analyzing these networks for statistical coincidence with the drug action networks originating from known and predicted drug-protein targets. Prioritized drugs shared between the two patients' PCa cells included carfilzomib (CFZ), bortezomib (BTZ), sulforaphane, and phenethyl isothiocyanate. The effects of these compounds were then tested in the CR cells, in vitro. We observed that the IC50 values of the normal PCa CR cells for CFZ and BTZ were higher than their matched tumor CR cells. Transcriptomic analysis of CFZ-treated CR cells revealed that genes involved in cell proliferation, proteases, and downstream targets of serine proteases were inhibited while KLK7 and KLK8 were induced in the tumor-derived CR cells.

CONCLUSIONS

Given that the drugs in the database are extremely well-characterized and that the patient-derived cells are easily scalable for high throughput drug screening, this combined in vitro and in silico approach may significantly advance personalized PCa treatment and for other cancer applications.

Abstract 2967: Microgel-based in vitro tumoroid platform for real time assessment of drug sensitivity and resistance

While 3D cell cultures have been used as suitable representatives of in vivo conditions compared to 2D systems, scalability and flexibility in designing such platforms has been a major challenge1. Micron-sized 3D culture platforms offer the possibility of high throughput analysis, however major challenges exist with respect to their overall design. Technical obstacles include difficulties in supporting multiple cell types (e.g. co-cultures of cancer associated fibroblasts (CAFs) and tumor cells) as well as enabling monitoring of important parameters, such as proliferation and metabolism, in real time. Our 3D co-culture systems are based on pancreatic ductal adenocarcinoma (PDAC) spheroid models in microgels, generated by coaxial droplet microfluidics. This allows for co-culturing of cancer cells with the supporting cell types that constitute the major portion of the actual tumor. Initial optimization experiments utilized co-culture of commercial pancreatic cancer cell lines such, as L3.6pl cells, and stromal CAFs. In addition to optimizing the 3D microcultures using commercial PDAC cell lines, we are also modifying the system to take advantage of patient-matched CAFs and conditionally reprogrammed (CR) primary PDAC cells. Both drug sensitive and isogenic nab-paclitaxel resistant PDAC CR cells will be used, as recently published2. Our preliminary data showed that our platform supports rapid generation of numerous identical spheroids inside the microgel. Using microscopy under different treatment conditions (e.g the presence/absence of drugs) we can quantify spheroid growth. In addition, spatio-temporal mapping of the microenvironmental parameters such as dissolved O2, pH and K+ during growth is performed by time lapse fluorescence microscopy using fluorescent silica microparticles embedded in the matrix. This process will yield an in-depth understanding of the kinetics of growth and associated biochemical and metabolic activity for each cell type (e.g. CAF and PDAC) under different treatment conditions. Our T3D platform offers a rapid, quantifiable assessment of the behavior of patient-derived cells in providing additional details related to the changing microenvironment and may advance our understanding of treatment response and failures.

The research leading to these results received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 759959, ERC-StG “INTERCELLMED”).

Reference

(1) Nunes et al. Biotechnol. Bioeng. 2019, 116 (1), 206-226.

(2) Parasido et al. Mol. Cancer Res. 2019, 17 (9), 1815-1827.

Citation Format: Anil Chandra, Saumya Prasad, Francesco Alemanno, Adriano Barra, Enza Lonardo, Erika Parasido, Christopher Albanese, Loretta L. del Mercato. Microgel-based in vitro tumoroid platform for real time assessment of drug sensitivity and resistance [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2967.

Abstract 1577: Gene expression studies using microgel embedded pancreatic cancer spheroids

Pancreatic ductal adenocarcinoma (PDAC) is known to be one of the deadliest cancers due to its late diagnosis and faster metastasis rate1. Thus, the time required to test the patient-derived cancer cells against different therapeutics becomes extremely crucial. Gene expression analysis using real-time PCR is vital, typically when designing patient-specific therapeutics. 2D tumor models do not represent the true picture of the tumor in vivo. In order to perform these gene expression studies, robust 3D cancer models are required2. The traditional techniques of generating cancer spheroids using U-bottom wells and hanging drop methods are effective but are limited by scalability as well as the limitations associated with the traditional organoid architecture. Gene expression studies of spheroids under different combinations of drug treatment thus requires many well defined and easy to handle spheroids. Here, we are trying to perform real-time PCR studies to access the gene expression changes on MIA PaCa-2 microgel based spheroids generated using co-axial droplet microfluidics with or without stromal cells. This 3D platform will enable gene expression studies in miniature co-culture tumor models. In addition, PCR and single-cell sequencing analyses will define the gene expression changes in the recently described conditionally reprogramed, patient-derived, primary PDAC cultures3. The establishment and analysis of this 3D model is fast, reproducible and can be easily scaled to enable high-throughput screening, thereby providing an opportunity to design patient-specific precision medicine.

The research leading to these results received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 759959, ERC-StG “INTERCELLMED”).

References:

(1) Adamska, A.; Domenichini, A.; Falasca, M. Pancreatic Ductal Adenocarcinoma: Current and Evolving Therapies. Int. J. Mol. Sci. 2017, 18 (7).

(2) Moreira, L.; Bakir, B.; Chatterji, P.; Dantes, Z.; Reichert, M.; Rustgi, A. K. Pancreas 3D Organoids: Current and Future Aspects as a Research Platform for Personalized Medicine in Pancreatic Cancer. Cell. Mol. Gastroenterol. Hepatol. 2018, 5 (3), 289-298.

(3) Parasido, E.; Avetian, G. S.; Naeem, A.; Graham, G.; Pishvaian, M.; Glasgow, E.; Mudambi, S.; Lee, Y.; Ihemelandu, C.; Choudhry, M.; et al. The Sustained Induction of C-MYC Drives Nab-Paclitaxel Resistance in Primary Pancreatic Ductal Carcinoma Cells. Mol. Cancer Res. 2019, 17 (9), 1815-1827.

Citation Format: Saumya Prasad, Anil Chandra, Enza Lonardo, Erika Parasido, Christopher Albanese, Loretta L. del Mercato. Gene expression studies using microgel embedded pancreatic cancer spheroids [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1577.

Abstract A48: Quantifying stroma-tumor cell interactions in three-dimensional cell culture systems

Background: In cancer research, studying cell motility is fundamental to investigate cancer invasion and drug resistance. In solid tumors constituted by a huge stroma component, such as pancreatic ductal adenocarcinoma (PDAC), the ability to quantify cell movement and interactions is mandatory to better understand the complex crosstalk between cancer and stroma cells. In PDAC, the pancreatic stellate cells (PSCs) are the principal source of dense fibrotic stroma: these closely interact with the PDAC cells to create a facilitating tumor microenvironment that supports local and distant tumor progression through the secretion and/or the response to a number of cytokines that globally increase cancer invasiveness; moreover, the dense tumor microenvironment contributes to resistance to chemotherapy and radiation therapy. Recent studies have established that targeting the stromal compartment in PDAC may lead to promising outcomes. Unfortunately, significant improvements in the overall survival of patients have not been realized in more than four decades, in part because of the lack of relevant preclinical models.

Methods: To infer interactions existing between stromal and cancer cells in complex 3D environments, we developed a novel platform that combines time-lapse fluorescence microscopy, automated image detection, and extensive statistical analysis. To better mimic in situ PDAC, we created a hydrogel-based (Matrigel, collagen) model that allows cell tracking in 4 dimensions (x, y, z, t), not possible in 2D, using a mixed population of L3.6PL pancreatic cancer cells and PSCs at a ratio of 25% and 75%, respectively. To precisely identify the two populations and facilitate automatic cell detection, cells were transfected with GFP and mCherry vectors. Once in the 3D conformation, the cocultures were monitored through time-lapse confocal microscopy (CLSM) in controlled conditions, and the dataset containing the temporal evolution of the cells was processed by statistical tools.

Results: Key to our approach was the generation of new machine learning-driven automated inferential protocols that resulted in the high-resolution imaging of the strength of the interactions between cells, as well as the potential presence of local chemokine gradients. In our ongoing studies, both commercial PDAC cell lines and pancreatic stellate cells were used to establish the model system. We are currently adopting the model to take full advantage of patient-derived PDAC cells established using the conditionally reprogrammed cells technique, mixed with patient-matched stellate cells. Since cell migration is a hallmark of cancer, we believe that this platform could be used as a reliable and reproducible approach for studying single-cell migration and invasion also in patient-derived models. The research leading to these results received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No. 759959, ERC-StG “INTERCELLMED”).

Citation Format: Marta Maria Cavo, Francesco Alemanno, Donatella Delle Cave, Eliana D'Amone, Adriano Barra, Enza Lonardo, Erika Parasido, Chris Albanese, Loretta Laureana del Mercato. Quantifying stroma-tumor cell interactions in three-dimensional cell culture systems [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr A48.

Pan-cancer analysis to identify a novel class of glucocorticoid and androgen receptor antagonists with potent anti-tumor activity

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Background: Large public cancer databases have allowed identification of novel mechanisms of oncogenesis and development of pharmacotherapies targeting these pathways. Examples are the androgen receptor (AR) and glucocorticoid receptor (GR). The Cancer Genome Atlas (TCGA) shows these receptors to have significantly increased expression over matched, normal tissue in several cancer types including: glioblastoma (AR and GR tumor-to-tissue ratios: AR = 6.53, GR = 1.42), low-grade gliomas (AR = 5.08, GR = 1.8), kidney clear cell carcinoma (AR = 1.89, GR = 1.82), kidney papillary cell carcinoma (AR = 3.64, GR = 1.2), and pancreatic adenocarcinoma (AR = 3.77, GR = 3.31). Methods: To investigate the therapeutic potential of targeting these receptors, we produced a series of analogues from a known GR inhibitor that all have the ability to target both the GR and the AR. Of these, PT150 is a clinical stage small molecule and PT157 is a preclinical stage small molecule. We began investigating the potential of these compounds to inhibit tumor growth using the NIH 60 cell lines panel with follow up in vitro testing and validation in clinically derived samples and established cell lines, including some cancers not include in the NIH 60 cell line panel or TCGA. Results: NIH 60 panel disclosed sensitivity towards gliomas, pancreatic cancer, and prostate cancer. For brain tumors, we investigated the effects of these inhibitors on glioblastoma, meningioma, and brain metastases. One analogue in particular, PT157, was able to significantly reduce cell viability after three days in culture in a dose dependent manor for each of the three tumor types and do so at a dose that is safely achievable in humans. Dose-dependent effects of PT150 and PT157 were observed in both androgen dependent and independent prostate cell lines, reducing viability of LNCaP, 22RV1 and DU145 cells. Similar data were also achieved in an in vitro pancreatic cancer model. Using patient-derived, primary pancreatic ductal adenocarcinoma (PDAC) cells, we found that both PT150 and PT157 were effective as monotherapies, inducing cell death in a dose dependent manner. In addition, both PT150 and PT157 significantly increased nab-paclitaxel sensitivity in nab-paclitaxel-resistant isogenic PDAC cells. Based on these in vitro data, we have begun pre-clinical experiments using in vivo mouse models. Conclusions: Our work has identified previously undescribed mechanisms of oncogenesis in several cancer types, as well as an efficacious class of novel compounds with the potential to inhibit them.

Inhibition of the mitochondrial citrate carrier, Slc25a1, reverts steatosis, glucose intolerance, and inflammation in preclinical models of NAFLD/NASH

Nonalcoholic fatty liver disease (NAFLD) and its evolution to inflammatory steatohepatitis (NASH) are the most common causes of chronic liver damage and transplantation that are reaching epidemic proportions due to the upraising incidence of metabolic syndrome, obesity, and diabetes. Currently, there is no approved treatment for NASH. The mitochondrial citrate carrier, Slc25a1, has been proposed to play an important role in lipid metabolism, suggesting a potential role for this protein in the pathogenesis of this disease. Here, we show that Slc25a1 inhibition with a specific inhibitor compound, CTPI-2, halts salient alterations of NASH reverting steatosis, preventing the evolution to steatohepatitis, reducing inflammatory macrophage infiltration in the liver and adipose tissue, while starkly mitigating obesity induced by a high-fat diet. These effects are differentially recapitulated by a global ablation of one copy of the Slc25a1 gene or by a liver-targeted Slc25a1 knockout, which unravel dose-dependent and tissue-specific functions of this protein. Mechanistically, through citrate-dependent activities, Slc25a1 inhibition rewires the lipogenic program, blunts signaling from peroxisome proliferator-activated receptor gamma, a key regulator of glucose and lipid metabolism, and inhibits the expression of gluconeogenic genes. The combination of these activities leads not only to inhibition of lipid anabolic processes, but also to a normalization of hyperglycemia and glucose intolerance as well. In summary, our data show for the first time that Slc25a1 serves as an important player in the pathogenesis of fatty liver disease and thus, provides a potentially exploitable and novel therapeutic target.

Clinicopathologic and prognostic significance of LGR5, a cancer stem cell marker in patients with colorectal cancer

Aim:

To analyze the clinicopathologic and prognostic significance of Leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), a cancer stem cell marker expression in a cohort of colorectal cancer patients (CRC).

Patients & methods:

A total of 76 formalin-fixed paraffin-embedded tissue blocks of primary or metastatic tumors from 49 CRC patients were collected for duration 2009–2015. LGR5 expression was assessed through immunohistochemical staining of a tissue microarray.

Results:

LGR5 was significantly over expressed in CRC tissue samples and found to be a statistically significant independent prognostic marker for an improved overall survival.

Conclusion:

LGR5 expression was higher in colorectal cancer than in normal tissue. LGR5 was an independent prognostic marker for better clinical outcomes and might be used as a potential therapeutic target in CRCs.

The Sustained Induction of c-MYC Drives Nab-Paclitaxel Resistance in Primary Pancreatic Ductal Carcinoma Cells

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with limited and, very often, ineffective medical and surgical therapeutic options. The treatment of patients with advanced unresectable PDAC is restricted to systemic chemotherapy, a therapeutic intervention to which most eventually develop resistance. Recently, nab-paclitaxel (n-PTX) has been added to the arsenal of first-line therapies, and the combination of gemcitabine and n-PTX has modestly prolonged median overall survival. However, patients almost invariably succumb to the disease, and little is known about the mechanisms underlying n-PTX resistance. Using the conditionally reprogrammed (CR) cell approach, we established and verified continuously growing cell cultures from treatment-naïve patients with PDAC. To study the mechanisms of primary drug resistance, nab-paclitaxel-resistant (n-PTX-R) cells were generated from primary cultures and drug resistance was verified in vivo, both in zebrafish and in athymic nude mouse xenograft models. Molecular analyses identified the sustained induction of c-MYC in the n-PTX-R cells. Depletion of c-MYC restored n-PTX sensitivity, as did treatment with either the MEK inhibitor, trametinib, or a small-molecule activator of protein phosphatase 2a. IMPLICATIONS: The strategies we have devised, including the patient-derived primary cells and the unique, drug-resistant isogenic cells, are rapid and easily applied in vitro and in vivo platforms to better understand the mechanisms of drug resistance and for defining effective therapeutic options on a patient by patient basis.

Paramagnetic Clusters of Mn3(O2CCH3)6(Bpy)2 in Polyacrylamide Nanobeads as a New Design Approach to a T1- T2 Multimodal Magnetic Resonance Imaging Contrast Agent

There is an increasing need for gadolinium-free magnetic resonance imaging (MRI) contrast agents, particularly for patients suffering from chronic kidney disease. Using a cluster-nanocarrier combination, we have identified a novel approach to the design of biomedical nanomaterials and report here the criteria for the cluster and the nanocarrier and the advantages of this combination. We have investigated the relaxivity of the following manganese oxo clusters: the parent cluster Mn₃(O₂CCH₃)₆(Bpy)₂ (1) where Bpy = 2,2'-bipyridine and three new analogs, Mn₃(O₂CC₆H₄CH═CH₂)₆(Bpy)₂ (2), Mn₃(O₂CC(CH₃)═CH₂)₆(Bpy)₂ (3), and Mn₃O(O₂CCH₃)₆(Pyr)₂ (4) where Pyr = pyridine. The parent cluster, Mn₃(O₂CCH₃)₆(Bpy)₂ (1), had impressive relaxivity ( r₁ = 6.9 mM^-1 s^-1, r₂ = 125 mM^-1 s^-1) and was found to be the most amenable for the synthesis of cluster-nanocarrier nanobeads. Using the inverse miniemulsion polymerization technique (1) in combination with the hydrophilic monomer acrylamide, we synthesized nanobeads (∼125 nm diameter) with homogeneously dispersed clusters within the polyacrylamide matrix (termed Mn₃Bpy-PAm). The nanobeads were surface-modified by co-polymerization with an amine-functionalized monomer. This enabled various postsynthetic modifications, for example, to attach a near-IR dye, Cyanine7, as well as a targeting agent. When evaluated as a potential multimodal MRI contrast agent, high relaxivity and contrast were observed with r₁ = 54.4 mM^-1 s^-1 and r₂ = 144 mM^-1 s^-1, surpassing T₁ relaxivity of clinically used Gd-DTPA chelates as well as comparable T₂ relaxivity to iron oxide microspheres. Physicochemical properties, cellular uptake, and impacts on cell viability were also investigated.

Abstract 342: Strigolactone analogues show potential as new combination therapy agents against pancreatic cancer

There is an increasing appreciation for combination therapy of antineoplastic drugs that target key pathways often through a synergistic effect, reducing the chance for tumor growth, self-renewal of cancer stem cell (CSC), spread of metastasis and drug resistance. The combination of DNA repair impairment and DNA damage was shown to be a successful approach. Previously, we had shown that strigolactone (SLs; synthetic analogues, SLAs), a novel class of phytohormones, causes DNA double strand breaks (DSBs) and inhibits breast and osteosarcoma cancer cells and CSC viability. Here, we tested whether SLAs inhibit the growth of pancreatic ductal adenocarcinoma (PDAC) cells and stem cells and whether SLAs sensitize the effects of Gemcitabine (Gemzar), the most commonly prescribed drug for PDAC patients. We show that SLAs induce DSBs in different PDAC cells and the combination of SLAs with Gemcitabine significantly increases apoptosis when compared to PDAC cells treated with Gemcitabine alone. This additive effect is independent of BRCA2 expression, which suggests that SLAs are effective at impairing multiple repair mechanisms and is suitable in combination with multiple DNA damaging agents. Interestingly, we show that SLAs sensitize patient-derived Gemcitabine non-responsive, PDAC Conditionally-Reprogrammed Cells (CRCs) to Gemcitabine, reducing their overall viability by more than 30%. Accordingly, the SLA- Gemcitabine combination has a significant impact on tumorsphere (CSCs) growth outcome. These findings demonstrate the potential for a novel drug combination of SLAs and Gemcitabine and underscore the potential of SLAs for multiple highly valuable translational applications regarding alternative therapies to combat cancer.

Citation Format: Matthew D. Park, Jefferson M. Haake, Erika Parasido, Christopher Albanese, Ronit I. Yarden. Strigolactone analogues show potential as new combination therapy agents against pancreatic cancer [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 342.

The mitochondrial citrate carrier, SLC25A1, drives stemness and therapy resistance in non-small cell lung cancer

Therapy resistance represents a clinical challenge for advanced non-small cell lung cancer (NSCLC), which still remains an incurable disease. There is growing evidence that cancer-initiating or cancer stem cells (CSCs) provide a reservoir of slow-growing dormant populations of cells with tumor-initiating and unlimited self-renewal ability that are left behind by conventional therapies reigniting post-therapy relapse and metastatic dissemination. The metabolic pathways required for the expansion of CSCs are incompletely defined, but their understanding will likely open new therapeutic opportunities. We show here that lung CSCs rely upon oxidative phosphorylation for energy production and survival through the activity of the mitochondrial citrate transporter, SLC25A1. We demonstrate that SLC25A1 plays a key role in maintaining the mitochondrial pool of citrate and redox balance in CSCs, whereas its inhibition leads to reactive oxygen species build-up thereby inhibiting the self-renewal capability of CSCs. Moreover, in different patient-derived tumors, resistance to cisplatin or to epidermal growth factor receptor (EGFR) inhibitor treatment is acquired through SLC25A1-mediated implementation of mitochondrial activity and induction of a stemness phenotype. Hence, a newly identified specific SLC25A1 inhibitor is synthetic lethal with cisplatin or with EGFR inhibitor co-treatment and restores antitumor responses to these agents in vitro and in animal models. These data have potential clinical implications in that they unravel a metabolic vulnerability of drug-resistant lung CSCs, identify a novel SLC25A1 inhibitor and, lastly, provide the first line of evidence that drugs, which block SLC25A1 activity, when employed in combination with selected conventional antitumor agents, lead to a therapeutic benefit.

Abstract 1083A: An ex vivo 3D bone metastasis model for prostate cancer

Introduction: Bone is the preferred site for prostate cancer (PCa) metastases and there is virtually no cure once the tumor is established within this niche. The development of therapeutic strategies against metastatic PCa has been limited by the lack of an all-human preclinical model to: (1) study PCa-bone interactions under physiologically relevant three dimensional (3D) microenvironments, (2) understand how these interactions result in the development of drug resistance, and (3) explore paradigm-changing precision medicine concepts.

Methods: Conditionally reprogrammed primary PCa cells (CR-PCa, derived from a lymph node metastatic site) were integrated with our ex vivo human 3D bone tissue platform, as a transformative approach for modeling tumor behavior at the bone niche. The 3D bone tissue was engineered using primary osteoblastic (OSB) cells from human bone samples. These cells were biomimetically assembly with biphasic calcium phosphate microbeads (BCPm) in perfusion microfluidic culture devices. BCPm were used to replicate the 3D cellular network of OSTs in human bone. This 3D tissue model was successfully used to support the osteocytic differentiation of primary human OSB cells within the BCPm structure, while maintaining a single cell layer of osteoblasts on the surface of the 3D tissue resembling the bone endosteum.

Results: Integration of the 3D bone tissue with CR-PCa cells resulted in a compromised endosteal layer after only 4 days of coculture, with more apoptotic OSTs in the tissues with CR-PCa vs. no PCa cells controls (P<0.01). For functional analysis, we stained 5 μm sections of the 3D tissues for alkaline phosphatase (ALP, an OSB marker) and sclerostin, an osteocytic marker and major signaling molecule released by embedded OSTs that suppresses osteoblastogenesis. Quantification of immunofluorescence staining revealed that ALP was significantly increased (P<0.05), whereas sclerostin significantly decreased (P<0.01) with the introduction of CR-PCa cells. This OSB phenotype, induced by PCa-bone interactions ex vivo, is entirely consistent with the OSB prostate cancer-bone metastasis niche seen in patients with advanced disease.

Conclusions: Our model recapitulates: (1) an OSB monolayer closely resembling the endosteum at the bone/ bone marrow interface, (2) the complex microphysiological features and functions of 3D-networked OSTs, and (3) the interactions of primary PCa cells with osteoblasts and OSTs.

Citation Format: Jenny Zilberberg, Saba Choudhary, Eugenia Dziopa, Cirian Mannion, Yair Kissin, Erika Parasido, Christopher Albanese, Woo Lee. An ex vivo 3D bone metastasis model for prostate cancer [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 1083A.

Characterization of the effects of defined, multidimensional culture conditions on conditionally reprogrammed primary human prostate cells

The inability to propagate human prostate epithelial cells indefinitely has historically presented a serious impediment to prostate cancer research. The conditionally reprogrammed cell (CRC) approach uses the combination of irradiated J2 mouse fibroblasts and a Rho kinase inhibitor such as Y27632 to support the continuous culture of cells derived from most epithelial tissues, including the prostate. Due to their rapid establishment and overall ease of use, CRCs are now widely used in a variety of basic and preclinical settings. In addition, CRCs were successfully used to clinically treat respiratory papillomatosis. Although both normal and tumor-derived prostate CRCs have been used to study the basic biology of prostate cancer and to test new therapies, certain limitations exist. We have previously reported that prostate CRCs form functional prostate glands when implanted under the mouse renal capsule. However in conventional culture, the prostate CRCs exist in an adult stem-like, transient amplifying state and consequently do not adequately recapitulate several important features of a differentiated prostate epithelium. To address these limitations, we previously described a transwell dish-based model that supported the culturing of prostate CRCs and the collection of cells and cell extracts for molecular and genetic analyses. Using normal and tumor-derived prostate CRCs, we describe the combined effects of the multi-dimensional transwell platform and defined culture media on prostate cellular proliferation, differentiation and signaling.

Abstract 4829: Development of rapid 3-dimensional culture conditions that support the in vitro differentiation of conditionally reprogrammed primary prostate cells for the study of prostate cancer

Despite decades of research into the causes and possible cures, prostate cancer (PCa) remains the second leading cause of cancer related death in men with over 26,000 deaths each year in the United States alone. While many of the studies performed over the years have identified important genes and signaling pathways that are involved in prostate carcinogenesis, the fact remains that due to the limited and suboptimal prostate cell lines available for correlative analyses, significant unmet needs exist in validating clinical findings. With this realization, many agencies such as the DOD and the NIH are funding more rapid and clinically relevant patient derived models to fill a void in our understanding of, and our ability to treat, cancer.

Our research has been on the forefront in development of a novel approach to use patient samples for basic, preclinical and clinical applications, significantly advancing personalized medicine with a revolutionary new primary cell culture technique termed conditionally reprogrammed cells (CRCs). In fact, the CRC approach is a major focus area of NIH U01/PAR 16-344.

We have pioneered the CRC technology for the rapid establishment and expansion of patient-derived normal and cancerous prostate cell lines in typical tissue culture conditions. We hypothesize that improved in vitro and in vivo platforms using patient-derived prostate cells (e.g. CRCs) are required for the elucidation and subsequent experimental verification of key molecular and genetic drivers for PCa as well as better curative approaches.

While prostate CRCs retain their lineage commitment, they fail to express many of the differentiation markers associated with luminal prostate cells when grown under normal two dimensional (2D) culture conditions. We have therefore established three dimensional (3D) non-spheroid based platforms for differentiation of both normal and malignant prostate CRCs. These include both transwell-based systems and decellularized tissue matrices that use defined differentiation medias to enable AR activation and a luminal cell phenotype. We have now demonstrated the in vitro re-engagement of key determinates in the AR pathway and differentiation to luminal prostate cells.

Documentation of the proper engagement of AR signaling is a significant step in developing a more accurate and tractable model for prostate cancer research and distinguishing between indolent and aggressive disease.

Citation Format: Lucas James Tricoli, Deborah Berry, Erika Parasido, Aisha Naeem, Olga Rodriguez, Iman Abdelgawad, Richard Lee, Adam Feldman, Chris Albanese. Development of rapid 3-dimensional culture conditions that support the in vitro differentiation of conditionally reprogrammed primary prostate cells for the study of prostate 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 4829. doi:10.1158/1538-7445.AM2017-4829

Thermoresponsive release of viable microfiltrated Circulating Tumor Cells (CTCs) for precision medicine applications

Stimulus responsive release of Circulating Tumor Cells (CTCs), with high recovery rates from their capture platform, is highly desirable for off-chip analyses. Here, we present a temperature responsive polymer coating method to achieve both release as well as culture of viable CTCs captured from patient blood samples.

The induction of the p53 tumor suppressor protein bridges the apoptotic and autophagic signaling pathways to regulate cell death in prostate cancer cells

The p53 tumor suppressor protein plays a crucial role in influencing cell fate decisions in response to cellular stress. As p53 elicits cell cycle arrest, senescence or apoptosis, the integrity of the p53 pathway is considered a key determinant of anti-tumor responses. p53 can also promote autophagy, however the role of p53-dependent autophagy in chemosensitivity is poorly understood. VMY-1-103 (VMY), a dansylated analog of purvalanol B, displays rapid and potent anti-tumor activities, however the pathways by which VMY works are not fully defined. Using established prostate cancer cell lines and novel conditionally reprogrammed cells (CRCs) derived from prostate cancer patients; we have defined the mechanisms of VMY-induced prostate cancer cell death. Herein, we show that the cytotoxic effects of VMY required a p53-dependent induction of autophagy, and that inhibition of autophagy abrogated VMY-induced cell death. Cancer cell lines harboring p53 missense mutations evaded VMY toxicity and treatment with a small molecule compound that restores p53 activity re-established VMY-induced cell death. The elucidation of the molecular mechanisms governing VMY-dependent cell death in cell lines, and importantly in CRCs, provides the rationale for clinical studies of VMY, alone or in combination with p53 reactivating compounds, in human prostate cancer.

Pilot phase I/II personalized therapy trial for metastatic colorectal cancer: evaluating the feasibility of protein pathway activation mapping for stratifying patients to therapy with imatinib and panitumumab

This nonrandomized phase I/II trial assessed the efficacy/tolerability of imatinib plus panitumumab in patients affected by metastatic colorectal cancer (mCRC) after stratification to treatment by selection of activated imatinib drug targets using reverse-phase protein array (RPPA). mCRC patients presenting with a biopsiable liver metastasis were enrolled. Allocation to the experimental and control arms was established using functional pathway activation mapping of c-Kit, PDGFR, and c-Abl phosphorylation by RPPA. The experimental arm received run-in escalation therapy with imatinib followed by panitumumab. The control arm received panitumumab alone. Seven patients were enrolled in the study. For three of the seven patients, sequential pre- and post-treatment biopsies were used to evaluate the effect of the therapeutic compounds on the drug targets and substrates. A decrease in the activation level of the drug targets and downstream substrates was observed in two of three patients. Combination therapy increased the activation of the AKT-mTOR pathway and several receptor tyrosine kinases. This study proposes a novel methodology for stratifying patients to personalized treatment based on the activation level of the drug targets. This workflow provides the ability to monitor changes in the signaling pathways after the administration of targeted therapies and to identify compensatory mechanisms.