Platinum sensitivity of ovarian cancer cells does not influence their ability to induce M2-type macrophage polarization

ProblemDevelopment of platinum resistance in ovarian cancer is mediated by both cancer cells and tumor microenvironment. Activation of epithelial-mesenchymal transition program in cancer cells may lead to enrichment for resistant clones. These processes can be affected by tumor-associated macrophages, a highly plastic population of cells that participate in tumor progression and response to treatment by shaping the microenvironment. We aimed to study how platinum resistance influences the crosstalk between macrophages and ovarian cancer cells. Method of studyUsing cisplatin-sensitive ovarian cancer cell line A2780, we developed and characterized cisplatin-resistant A2780Cis and cisplatin and doxorubicin co-resistant A2780Dox cell lines. Next, we set up an indirect coculture system with THP-1 cell line-derived M0-type-, M1-type- and M2-type-like polarized macrophages. We monitored the expression of genes associated with cellular stemness, multidrug resistance, and epithelial-mesenchymal transition in cancer cells, and expression profile of M1/M2 markers in macrophages. ResultsDevelopment of drug resistance in ovarian cancer cell lines was accompanied by increased migration, clonogenicity, and upregulated expression of transcription factors, associated with cellular stemness and epithelial-mesenchymal transition. Upon coculture, we noted that the most relevant changes in gene expression profile occurred in A2780 cells. Moreover, M0- and M1-type macrophages, but not M2-type macrophages, showed significant transcriptional alterations. ConclusionOur results provide the evidence for bidirectional interplay between cancer cells and macrophages. Independent of platinum resistance status, ovarian cancer cells polarize macrophages toward M2-like type, whereas macrophages induce epithelial-mesenchymal transition and stemness-related gene expression profile in cisplatin-sensitive, but not cisplatin-resistant cancer cells.

A distinguishing gene signature shared by tumor-infiltrating Tie2-expressing monocytes, blood "resident" monocytes, and embryonic macrophages suggests common functions and developmental relationships

Daniela Biziato, Michele De Palma, Ferdinando Pucci

We previously showed that Tie2-expressing monocytes (TEMs) have nonredundant proangiogenic activity in tumors. Here, we compared the gene expression profile of tumor-infiltrating TEMs with that of tumor-associated macrophages (TAMs), spleen-derived Gr1(+)Cd11b(+) neutrophils/myeloid-derived suppressor cells, circulating "inflammatory" and "resident" monocytes, and tumor-derived endothelial cells (ECs) by quantitative polymerase chain reaction-based gene arrays. TEMs sharply differed from ECs and Gr1(+)Cd11b(+) cells but were highly related to TAMs. Nevertheless, several genes were differentially expressed between TEMs and TAMs, highlighting a TEM signature consistent with enhanced proangiogenic/tissue-remodeling activity and lower proinflammatory activity. We validated these findings in models of oncogenesis and transgenic mice expressing a microRNA-regulated Tie2-GFP reporter. Remarkably, resident monocytes and TEMs on one hand, and inflammatory monocytes and TAMs on the other hand, expressed coordinated gene expression profiles, suggesting that the 2 blood monocyte subsets are committed to distinct extravascular fates in the tumor microenvironment. We further showed that a prominent proportion of embryonic/fetal macrophages, which participate in tissue morphogenesis, expressed distinguishing TEM genes. It is tempting to speculate that Tie2(+) embryonic/fetal macrophages, resident blood monocytes, and tumor-infiltrating TEMs represent distinct developmental stages of a TEM lineage committed to execute physiologic proangiogenic and tissue-remodeling programs, which can be co-opted by tumors.

2009

Roles of Epigenetic Dysregulation in Cancer Progression and Metastasis

Mohammad Sadegh Saghafinia

Nearly all the cells of an organism share the same DNA sequence or genome, and yet they show different phenotypes and carry out different functions. This diversity is made possible by a verity of molecular modifications acting on the DNA sequence that collectively define the cell's epigenome. Failure in the proper regulation of epigenome can lead to abnormal activation or inhibition of vital signaling pathways, which contributes to the initiation and progression of multiple diseases, including cancer. In this thesis, I used a combination of in silico, in vitro, and in vivo techniques to explore the roles of epigenetic dysregulation in tumor progression and metastasis. In the first part, I performed a systematic and unbiased investigation of cancer-associated DNA methylation and gene expression changes across human cancers. I designed a novel algorithmic approach (RESET) to identify aberrant DNA methylation and associated gene expression changes across >6,000 human tumors. We identified a DNA Methylation Instability (DMI) phenotype in tumors acquiring numerous hyper and hypomethylated transcription start sites, which is associated with mutations of chromatin remodeling factors and Wnt-signaling. We showed that silenced genes coalesced in specific pathways including apoptosis, transcriptional regulation, and cell metabolism. The majority of the enhanced genes belonged to cancer-germline antigens (CG), whose expression correlated with response to anti-PD-1 in melanoma patients. Finally, we demonstrated the potential of RESET to explore aberrant DNA methylation in pediatric tumors; pediatric Wilms tumors with diffuse anaplasia exhibit DMI, and specific silencing events predict a worse outcome in cases with favorable histology. These results established a new approach to explore pan-cancer epigenetic modifications and provided a resource of candidate oncogenic events for future functional and therapeutic studies. In the second part, I studied the dynamics of cancer progression and metastasis in Pancreatic Neuroendocrine Tumors (PanNET). This rare tumor is the second most common form of pancreatic cancer. Two principal subtypes of PanNET has been identified: insulinomas (IT) and metastasis-like primaries (MLP), corresponding to the low and high grade of human PanNETs, respectively. From the mouse model of PanNET (RT2), we profiled the single-cell, bulk mRNA and miRNA transcriptomes, and the proteomes of primary and metastasis specimens. We demonstrated that the tumor progression from IT to MLP follows the reverse embryonic and postnatal developmental path. Transcriptomic data from human patients showed that aggressive human PanNETs also follow the same reverse developmental trajectory of dedifferentiation. We established one possible mechanism underlying IT-to-MLP transition. Over-expression of the miR-181cd cluster in IT-like cancer cell-lines resulted in acquisition of the MLP phenotypes. miR-181cd mediated its effect through suppressing the expression of Meis2 and, indirectly, inducing the expression of Hmgb3 and Mycn transcription factors. Inhibiting the expression of Hmgb3 in MLP-like cancer cell-lines resulted in a significant growth decrease both in vitro and in vivo, demonstrating the importance of Hmgb3 in the maintenance of MLP-like cell state. These data presented dedifferentiation as a mechanism by which malignant neuroendocrine cancer cells acquire progenitor-like features, enabling them to become more aggressive and metastatic.

EPFL2020

Bioengineered 3D platform to explore cell-ECM interactions and drug resistance of epithelial ovarian cancer cells

Matthias Lütolf, Simone Rizzi

The behaviour of cells cultured within three-dimensional (3D) structures rather than onto two-dimensional (2D) culture plastic more closely reflects their in vivo responses. Consequently, 3D culture systems are becoming crucial scientific tools in cancer cell research. We used a novel 3D culture concept to assess cell-matrix interactions implicated in carcinogenesis: a synthetic hydrogel matrix equipped with key biomimetic features, namely incorporated cell integrin-binding motifs (e.g. RGD peptides) and the ability of being degraded by cell-secreted proteases (e.g. matrix metalloproteases). As a cell model, we chose epithelial ovarian cancer, an aggressive disease typically diagnosed at an advanced stage when chemoresistance occurs. Both cell lines used (OV-MZ-6, SKOV-3) proliferated similarly in 2D, but not in 3D. Spheroid formation was observed exclusively in 3D when cells were embedded within hydrogels. By exploiting the design flexibility of the hydrogel characteristics, we showed that proliferation in 3D was dependent on cell-integrin engagement and the ability of cells to proteolytically remodel their extracellular microenvironment. Higher survival rates after exposure to the anti-cancer drug paclitaxel were observed in cell spheroids grown in hydrogels (40-60%) compared to cell monolayers in 2D (20%). Thus, 2D evaluation of chemosensitivity may not reflect pathophysiological events seen in patients. Because of the design flexibility of their characteristics and their stability in long-term cultures (28 days), these biomimetic hydrogels represent alternative culture systems for the increasing demand in cancer research for more versatile, physiologically relevant and reproducible 3D matrices. Copyright © 2010 Elsevier Ltd. All rights reserved.

Elsevier2010

Roles of Epigenetic Dysregulation in Cancer Progression and Metastasis

Mohammad Sadegh Saghafinia

EPFL2020