A three-dimensional co-culture system to investigate macrophage-dependent tumor cell invasion

Abstract

Macrophages infiltrate cancers and promote progression to invasion and metastasis. To directly examine tumor-associated macrophages (TAMs) and tumor cells interacting and co-migrating in a three-dimensional (3D) environment, we have developed a co-culture model that uses a PyVmT mouse mammary tumor-derived cell line and mouse bone marrow-derived macrophages (BMM). The Py8119 cell line was cloned from a spontaneous mammary tumor in a Tg(MMTV:LTR-PyVmT) C57Bl/6 mouse and these cells form 3-dimensional (3D) spheroids under conditions of low adhesion. Co-cultured BMM infiltrate the Py8119 mammospheres and embedding of the infiltrated mammospheres in Matrigel leads to subsequent invasion of both cell types into the surrounding matrix. This physiologically relevant co-culture model enables examination of two critical steps in the promotion of invasion and metastasis by BMM: 1) macrophage infiltration into the mammosphere and, 2) subsequent invasion of macrophages and tumor cells into the matrix. Our methodology allows for quantification of BMM infiltration rates into Py8119 mammospheres and demonstrates that subsequent tumor cell invasion is dependent upon the presence of infiltrated macrophages. This method is also effective for screening macrophage motility inhibitors. Thus, we have developed a robust 3D in vitro co-culture assay that demonstrates a central role for macrophage motility in the promotion of tumor cell invasion.

Targeted Delivery of siRNA Lipoplexes to Cancer Cells Using Macrophage Transient Horizontal Gene Transfer

“…Monocytes/macrophages present a competitive advantage for delivery into the tumor environment because of the high recruitment and proliferation that occurs during tumorigenesis. [2,46,47] Furthermore, monocyte based cell therapies already exist in other disease contexts and have shown some efficacy. [58,59] Immunogenicity must be considered; however it is likely to be similar to other types of autologous cell therapies.…”

“…Macrophages reside in the tissue, however, monocytes, their bloodborne precursors are an ideal cell type for cell therapy because they are easily harvested from the bloodstream. Monocytes/macrophages present a competitive advantage for delivery into the tumor environment because of the high recruitment and proliferation that occurs during tumorigenesis . Furthermore, monocyte based cell therapies already exist in other disease contexts and have shown some efficacy .…”

“…The enhanced permeability and retention (EPR) effect, which the promise of cancer nanotechnology has partially relied on, has proved more heterogeneous and unpredictable than anticipated. In contrast to the limitations of nanoparticles, immune cells are an optimal drug delivery vehicle due to their ability to cross‐navigate the blood and lymphatic circulatory system, penetrate the blood–brain barrier, the fibrotic exterior of a tumor, or other barriers, and actively accumulate in diseased regions . Combining the benefits of nanoparticle encapsulation and stability with the intrinsic trafficking, phagocytosis, and secretion activity of immune cells may be the best combination to achieve therapeutic doses.…”

Promotion of Tumor Invasion by Tumor-Associated Macrophages: The Role of CSF-1-Activated Phosphatidylinositol 3 Kinase and Src Family Kinase Motility Signaling

“…In particular, TAMs play a critical role in encouraging tumor invasion through induction of a paracrine dialog between tumor cells and closely associated TAMs, which leads to their co-migration and invasion away from the primary tumor [56,58,59]. Consistent with this, 3D studies of mammary tumor spheroid invasion demonstrate that tumor cells are incapable of invasion into the surrounding matrix unless the spheroids are infiltrated with macrophages, indicating that macrophages trigger and support tumor cell invasiveness [106,116]. Live imaging of the tumor cells and macrophages highlights the streams of co-migrating macrophages and tumor cells as they invade the Matrigel and macrophages can be seen encouraging tumor cell migration as they follow macrophages through tunnels previously dug by those macrophages [106].…”

Targeting colony stimulating factor-1 receptor signalling to treat ectopic pregnancy

“…The effect of GW2580 and CSF-1 ligand on proliferation of SW.71 cells, was analysed using CellTiter 96 Aqueous (MTS) kit (Promega, Southampton, UK) as per the manufacturers' recommended protocol. To optimise concentrations of treatments GW2580 (Selleckchem, Munich, Germany) was examined at 5 µM-40 µM 32 and CSF-1 ligand (recombinant human MCSF, BioLegend, California, USA) was tested at 50-200 ng/mL 33 tissue resources. This study was approved by the Scotland A Research Ethics Committee (LREC 04/ S1103/20) and written informed consent was taken from all study participants.…”