An Extracellular Matrix Overlay Model for Bioluminescence Microscopy to Measure Single-Cell Heterogeneous Responses to Antiandrogens in Prostate Cancer Cells

Prostate cancer (PCa) displays diverse intra-tumoral traits, impacting its progression and treatment outcomes. This study aimed to refine PCa cell culture conditions for dynamic monitoring of androgen receptor (AR) activity at the single-cell level. We introduced an extracellular matrix-Matrigel (ECM-M) culture model, enhancing cellular tracking during bioluminescence single-cell imaging while improving cell viability. ECM-M notably tripled the traceability of poorly adherent PCa cells, facilitating robust single-cell tracking, without impeding substrate permeability or AR response. This model effectively monitored AR modulation by antiandrogens across various PCa cell lines. Single-cell imaging unveiled heterogeneous antiandrogen responses within populations, correlating non-responsive cell proportions with drug IC50 values. Integrating ECM-M culture with the PSEBC-TSTA biosensor enabled precise characterization of ARi responsiveness within diverse cell populations. Our ECM-M model stands as a promising tool to assess heterogeneous single-cell treatment responses in cancer, offering insights to link drug responses to intracellular signaling dynamics. This approach enhances our comprehension of the nuanced and dynamic nature of PCa treatment responses.

Cancer-Associated Fibroblasts in a 3D Engineered Tissue Model Induce Tumor-like Matrix Stiffening and EMT Transition

Simple Summary

The physical properties of a tumor, such as stiffness, are important drivers of tumor progression. However, current in vitro tumor models fail to recapitulate the full range of physical properties observed in solid tumors. Here, we proposed a 3D self-assembly engineered bladder model using cancer-associated fibroblasts in which stromal cells produce their extracellular matrix. We then proceeded to assess how our model recapitulates biological and mechanical features found in tumors. We confirmed that stroma assembled by cancer-associated fibroblasts have increased extracellular matrix content and display increased remodeling and higher stiffness. Moreover, normal urothelial cells seeded on the tumor model displayed a mechanotransduction response, increased cell proliferation, cell infiltration within stroma, and displayed features of the epithelial-to-mesenchymal transition. Altogether, we demonstrated that our cancer-associated fibroblast-derived tumor stroma recapitulates several biological and physical features expected from a tumor-like environment and, thus, provides the basis for more accurate cancer models.

Abstract

A tumor microenvironment is characterized by its altered mechanical properties. However, most models remain unable to faithfully recreate the mechanical properties of a tumor. Engineered models based on the self-assembly method have the potential to better recapitulate the stroma architecture and composition. Here, we used the self-assembly method based on a bladder tissue model to engineer a tumor-like environment. The tissue-engineered tumor models were reconstituted from stroma-derived healthy primary fibroblasts (HFs) induced into cancer-associated fibroblast cells (iCAFs) along with an urothelium overlay. The iCAFs-derived extracellular matrix (ECM) composition was found to be stiffer, with increased ECM deposition and remodeling. The urothelial cells overlaid on the iCAFs-derived ECM were more contractile, as measured by quantitative polarization microscopy, and displayed increased YAP nuclear translocation. We further showed that the proliferation and expression of epithelial-to-mesenchymal transition (EMT) marker in the urothelial cells correlate with the increased stiffness of the iCAFs-derived ECM. Our data showed an increased expression of EMT markers within the urothelium on the iCAFs-derived ECM. Together, our results demonstrate that our tissue-engineered tumor model can achieve stiffness levels comparable to that of a bladder tumor, while triggering a tumor-like response from the urothelium.

18F-Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) is accurate for high-grade prostate cancer bone staging when compared to bone scintigraphy

INTRODUCTION

In this study, we compared ¹⁸F-FDG-postron emission tomography/computed tomography (PET/CT) and bone scintigraphy accuracies for the detection of bone metastases for primary staging in high-grade prostate cancer (PCa) patients to determine if ¹⁸F-FDG-PET/CT could be used alone as a staging modality.

METHODS

Men with localized high-grade PCa (n=256, Gleason 8-10, International Society of Urological Pathology [ISUP] grades 4 or 5) were imaged with bone scintigraphy and ¹⁸F-FDGPET/CT. We compared on a per-patient basis the accuracy of the two imaging modalities, taking intermodality agreement as the standard of truth (SOT).

RESULTS

¹⁸F-FDG-PET/CT detected at least one bone metastasis in 33 patients compared to only 26 with bone scan. Of the seven false-negative bone scintigraphies, four (57.1%) were solitary metastases (monometastatic), three (42.9%) were oligometastatic (2-4 lesions), and none were plurimetastatic (>4 lesions). Compared to SOT, ¹⁸F-FDG-PET/CT showed higher sensitivity and accuracy than bone scintigraphy (100% vs. 78.8%, and 98.7% vs. 98.2%) for the detection of skeletal lesions.

CONCLUSIONS

¹⁸F-FDG-PET/CT appears similar or better than conventional bone scans to assess for bone metastases in patients newly diagnosed with high-grade PCa. Since intraprostatic FDG-uptake is also a biomarker of failure to radical prostatectomy and that FDG-PET/CT has been shown to be accurate in detecting PCa lymph node metastasis, FDG-PET/CT has the potential to be used as the sole preoperative staging modality in high-grade PCa.

TGFβ Signaling in the Tumor Microenvironment

Transforming growth factor beta (TGFβ) is a pleiotropic growth factor. Under normal physiological conditions, TGFβ maintains homeostasis in mammalian tissues by restraining the growth of cells and stimulating apoptosis. However, the role of TGFβ signaling in the carcinogenesis is complex. TGFβ acts as a tumor suppressor in the early stages of disease and as a tumor promoter in its later stages where cancer cells have been relieved from TGFβ growth controls. Overproduction of TGFβ by cancer cells lead to a local fibrotic and immune-suppressive microenvironment that fosters tumor growth and correlates with invasive and metastatic behavior of the cancer cells. Here, we present an overview of the complex biology of the TGFβ family, and we discuss the roles of TGFβ signaling in carcinogenesis and how this knowledge is being leveraged to develop TGFβ inhibition therapies against the tumor.

GLUT1 expression in high-risk prostate cancer: Correlation with 18F-FDG-PET/CT and clinical outcome

291

Background: Tumour FDG-uptake is of prognostic value in high-risk and metastatic prostate cancer (PCa). The aim of this study is to investigate the underlying glucose metabolism mechanisms of 18F-FDG-uptake on PET/CT imaging in PCa. Methods: Retrospective analysis was conducted for 94 patients diagnosed with a Gleason sum ≥8 at biopsy who underwent 18F-FDG-PET/CT imaging before radical prostatectomy. GLUT1, GLUT12 and HK2 expression were blindly scored after immunohistochemistry on radical prostatectomy specimens by 3 pathologists. 18F-FDG-uptake in primary lesion was measured by a blinded reader using maximum standardized uptake value (SUVmax). Correlations between GLUT1, GLUT12 and HK2 and SUVmax were assessed using Spearman’s rank correlation test. Survival probabilities were based on the Kaplan-Meier method. Results: With a median follow-up of 4.5 years, 56% (n=53) of patients had biochemical recurrence, 7% (n=7) progressed to castration-resistant PCa (CRPC) disease, 13% (n=12) developed metastasis and 6% (n=6) died. Correlation was found between GLUT1 expression and SUVmax level (r=0.2512, p=0.0182). In addition, SUVmax was significantly higher in tumours with high GLUT1 expression (n=17, 5.74±1.67) than tumours with low GLUT1 expression (n=71, 2.68±0.31, P=0.0037). Also, contrary to GLUT12 and HEX2 expression, a significant association was found between GLUT-1 expression levels and SUVmax index (p=0.004), lymph node status (p=0.046), volume of cancer (P=0.013), CRPC-free survival (p=0.02) and metastasis-free survival (p=0.04). Conclusions: GLUT1 expression in PCa tumours correlates with 18F-FDG-uptake and poor prognostic factors. These results suggest that this transporter is involved in the molecular mechanism of 18F-FDG-uptake in high-risk PCa and raise interest in targeting metabolic dependencies of PCa cells as a selective anticancer strategy.

GLUT1 expression in high-risk prostate cancer: correlation with 18F-FDG-PET/CT and clinical outcome

BACKGROUND

Tumour ¹⁸F-FDG-uptake is of prognostic value in high-risk and metastatic prostate cancer (PCa). The aim of this study is to investigate the underlying glucose metabolism mechanisms of ¹⁸F-FDG-uptake on PET/CT imaging in PCa.

METHODS

Retrospective analysis was conducted for 94 patients diagnosed with a Gleason sum ≥8 adenocarcinoma of the prostate at biopsy between July 2011 and July 2014 who underwent ¹⁸F-FDG-PET/CT imaging before radical prostatectomy (RP). ¹⁸F-FDG-uptake in primary lesion was measured by a blinded reader using maximum standardised uptake value (SUV_max). GLUT1, GLUT12 and HK2 expression were blindly scored after immunohistochemistry on specimens RP by three pathologists. Correlations between GLUT1, GLUT12 and HK2, and SUV_max were assessed using Spearman's rank correlation test. Survival probabilities were based on the Kaplan-Meier method.

RESULTS

With a median follow-up of 4.5 years, 56% (n = 53) of patients had biochemical recurrence (BCR), 7% (n = 7) progressed to castration-resistant prostate cancer (CRPC) disease, 13% (n = 12) developed metastasis and 6% (n = 6) died. Correlation was found between GLUT1 expression and SUVmax level (r = 0.25, p = 0.02). In addition, SUV_max was significantly higher in tumours with high GLUT1 expression (n = 17, 5.74 ± 1.67) than tumours with low GLUT1 expression (n = 71, 2.68 ± 0.31, p = 0.004). Moreover, a significant association was found between GLUT1 expression levels and SUV_max level (p = 0.005), lymph node status (p = 0.05), volume of cancer (p = 0.01), CRPC disease progression (p = 0.02) and metastasis development (p = 0.04). No significant difference between GLUT12 and HEX2 expression and SUV_max have been found.

CONCLUSIONS

GLUT1 expression in PCa tumours correlates with ¹⁸F-FDG-uptake and poor prognostic factors. These results suggest that this transporter is involved in the molecular mechanism of ¹⁸F-FDG-uptake in high-risk PCa and raise interest in targeting metabolic dependencies of PCa cells as a selective anticancer strategy.

Cancer-associated fibroblasts induce epithelial-mesenchymal transition of bladder cancer cells through paracrine IL-6 signalling

BACKGROUND

Cancer-associated fibroblasts (CAFs), activated by tumour cells, are the predominant type of stromal cells in cancer tissue and play an important role in interacting with neoplastic cells to promote cancer progression. Epithelial-mesenchymal transition (EMT) is a key feature of metastatic cells. However, the mechanism by which CAFs induce EMT program in bladder cancer cells remains unclear.

METHODS

To investigate the role of CAFs in bladder cancer progression, healthy primary bladder fibroblasts (HFs) were induced into CAFs (iCAFs) by bladder cancer-derived exosomes. Effect of conditioned medium from iCAFs (CM iCAF) on EMT markers expression of non-invasive RT4 bladder cancer cell line was determined by qPCR and Western blot. IL6 expression in iCAFs was evaluated by ELISA and Western blot. RT4 cell proliferation, migration and invasion were assessed in CM iCAF +/- anti-IL6 neutralizing antibody using cyQUANT assay, scratch test and transwell chamber respectively. We investigated IL6 expression relevance for bladder cancer progression by querying gene expression datasets of human bladder cancer specimens from TCGA and GEO genomic data platforms.

RESULTS

Cancer exosome-treated HFs showed CAFs characteristics with high expression levels of αSMA and FAP. We showed that the CM iCAF induces the upregulation of mesenchymal markers, such as N-cadherin and vimentin, while repressing epithelial markers E-cadherin and p-ß-catenin expression in non-invasive RT4 cells. Moreover, EMT transcription factors SNAIL1, TWIST1 and ZEB1 were upregulated in CM iCAF-cultured RT4 cells compared to control. We also showed that the IL-6 cytokine was highly expressed by CAFs, and its receptor IL-6R was found on RT4 bladder cancer cells. The culture of RT4 bladder cancer cells with CM iCAF resulted in markedly promoted cell growth, migration and invasion. Importantly, inhibition of CAFs-secreted IL-6 by neutralizing antibody significantly reversed the IL-6-induced EMT phenotype, suggesting that this cytokine is necessary for CAF-induced EMT in the progression of human bladder cancer. Finally, we observed that IL6 expression is up-regulated in aggressive bladder cancer and correlate with CAF marker ACTA2.

CONCLUSIONS

We conclude that CAFs promote aggressive phenotypes of non-invasive bladder cancer cells through an EMT induced by the secretion of IL-6.

Exosomes Induce Fibroblast Differentiation into Cancer-Associated Fibroblasts through TGFβ Signaling

A particularly important tumor microenvironment relationship exists between cancer cells and surrounding stromal cells. Fibroblasts, in response to cancer cells, become activated and exhibit myofibroblastic characteristics that favor invasive growth and metastasis. However, the mechanism by which cancer cells promote activation of healthy fibroblasts into cancer-associated fibroblasts (CAF) is still not well understood. Exosomes are nanometer-sized vesicles that shuttle proteins and nucleic acids between cells to establish intercellular communication. Here, bladder cancer-derived exosomes were investigated to determine their role in the activation of healthy primary vesical fibroblasts. Exosomes released by bladder cancer cells are internalized by fibroblasts and promoted the proliferation and expression of CAF markers. In addition, cancer cell-derived exosomes contain TGFβ and in exosome-induced CAFs SMAD-dependent signaling is activated. Furthermore, TGFβ inhibitors attenuated CAF marker expression in healthy fibroblasts. Therefore, these data demonstrate that bladder cancer cells trigger the differentiation of fibroblasts to CAFs by exosomes-mediated TGFβ transfer and SMAD pathway activation. Finally, exosomal TGFβ localized inside the vesicle and contributes 53.4% to 86.3% of the total TGFβ present in the cancer cell supernatant. This study highlights a new function for bladder cancer exosomes as novel modulators of stromal cell differentiation.Implication: This study identifies exosomal TGFβ as new molecular mechanism involved in cancer-associated fibroblast activation. Mol Cancer Res; 16(7); 1196-204. ©2018 AACR.

Abstract 5791: 3D tissue engineering bladder model for cancer invasion study

INTRODUCTION: Our understanding of the biological processes involved in bladder cancer (BCa) is greatly limited by the models currently available. In fact, the combination of in vitro and in vivo models of BCa has failed to elucidate all the fundamental aspects of the disease. The eighth most commonly diagnosed cancer in Western societies, BCa has become a growing public health concern, and more realistic models are needed to reveal the mechanisms involved in tumor initiation and progression. METHODS: Bladder substitutes have been constructed by tissue engineering with healthy human fibroblasts and urothelial cells, using the self-assembly method. Meanwhile, spheroids have been produced from non-invasive (RT4) and invasive (T24) BCa cell lines expressing DsRed fluorescent protein. The invasive potential of these spheroids was characterized in a type-I collagen gel (2.5mg/mL). Then, the spheroids were implanted on the surface of bladder substitutes, after which their development was followed by fluorescence microscopy. RESULTS: Both of the cancer cell lines used were able to form compact spheroids and grow on bladder equivalents. The invasive behaviour of spheroids varied depending on the nature of the cells used. The non-invasive RT4 cell line was unable to cross the basal lamina whereas the invasive T24 cell line was able to do so. CONCLUSION: The establishment of such a model for studying cancer biology in a physiological environment will help bridge the gap between overly simple cell culture models and more complex transgenic mice models. This new model offers a unique opportunity to study separately the players involved in the development of BCa and thus represents a powerful tool for the mechanistic analysis of this complex pathology.

Citation Format: Cassandra Ringuette Goulet, Geneviève Bernard, Stéphane Chabaud, Frédéric Pouliot, Stéphane Bolduc. 3D tissue engineering bladder model for cancer invasion study [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 5791. doi:10.1158/1538-7445.AM2017-5791

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