A humanized orthotopic tumor microenvironment alters the bone metastatic tropism of prostate cancer cells

Abstract

Prostate cancer (PCa) is the second most commonly diagnosed cancer in men, and bone is the most frequent site of metastasis. The tumor microenvironment (TME) impacts tumor growth and metastasis, yet the role of the TME in PCa metastasis to bone is not fully understood. We used a tissue-engineered xenograft approach in NOD-scid IL2Rγnull (NSG) mice to incorporate two levels of humanization; the primary tumor and TME, and the secondary metastatic bone organ. Bioluminescent imaging, histology, and immunohistochemistry were used to study metastasis of human PC-3 and LNCaP PCa cells from the prostate to tissue-engineered bone. Here we show pre-seeding scaffolds with human osteoblasts increases the human cellular and extracellular matrix content of bone constructs, compared to unseeded scaffolds. The humanized prostate TME showed a trend to decrease metastasis of PC-3 PCa cells to the tissue-engineered bone, but did not affect the metastatic potential of PCa cells to the endogenous murine bones or organs. On the other hand, the humanized TME enhanced LNCaP tumor growth and metastasis to humanized and murine bone. Together this demonstrates the importance of the TME in PCa bone tropism, although further investigations are needed to delineate specific roles of the TME components in this context.

Targeting the BMP Pathway in Prostate Cancer Induced Bone Disease

“…We still hope that a model of experimental bone metastases that progresses from a localized bone to a soft tissue secondary metastasis such as liver or lung would be more fully developed to gauge the progression of disease demonstrated in patients. metastatic prostate cancer (41). Whichever the route of cells, it is fundamental to the nuance of cell survival prior to extravasation compared to direct inoculation into a wounded matrix.…”

GelMA and Biomimetic Culture Allow the Engineering of Mineralized, Adipose, and Tumor Tissue Human Microenvironments for the Study of Advanced Prostate Cancer In Vitro and In Vivo

“…For IHC, dewaxed and rehydrated sections were treated as previously described. [ 26 ] When targeting intracellular proteins, paraffin sections were permeabilized with 0.1% Triton X‐100 in PBS for 6 min. For antigen retrieval, trisodium citrate buffer (pH 6) or 10% EDTA (pH 7.4) were used for either 5 min at 95 °C or 20 min at 80 °C, and proteinase K (Dako, Glostrup, Denmark) for 5–15 min at room temperature.…”

“…In addition to being an appropriate tool for in vitro 3D platforms, GelMA hydrogels can also be used for in vivo studies as a biocompatible and biodegradable cell carrier, allow-J. Gunter Centre for Genomics and Personalised Health QUT Brisbane, QLD 4102, Australia ing human tissue formation in vivo, [16,26] and therefore represent an ideal candidate for both the in vitro and in vivo engineering of the human bone tumor microenvironment.…”

“…Morphological features of bone were observed [28,29] and these models allowed the study of metastatic PCa and other malignancies. [26,28,30] However, these models did not allow studying the interactions between human BM-adipocytes and PCa cells within the humanized bone microenvironment as BMadipocytes were of murine origin.…”

“…[ 18 ] GelMA is a well‐established hydrogel, [ 19,20 ] widely used to grow cells from the bone microenvironment, including bone marrow mesenchymal stem cells (BM‐MSCs), [ 21,22 ] osteoprogenitors, [ 23 ] adipocytes [ 21,24 ] as well as cancer cells, such as prostate cancer cells, [ 16,25 ] and represent an excellent alternative to Matrigel and collagen‐based hydrogels, whose stiffnesses cannot easily be tuned to mimic specific microenvironments. In addition to being an appropriate tool for in vitro 3D platforms, GelMA hydrogels can also be used for in vivo studies as a biocompatible and biodegradable cell carrier, allowing human tissue formation in vivo, [ 16,26 ] and therefore represent an ideal candidate for both the in vitro and in vivo engineering of the human bone tumor microenvironment.…”