Introduction

Circulating tumor cells (CTCs) are key mediators of prostate cancer metastasis, but their rarity in blood limits detection and interrogation. Implanted biomaterial scaffolds have been used as artificial niches for capturing CTCs from primary breast cancer tumors in xenograft models. In this study, we aim to adapt this approach to prostate cancer CTCs using the well-characterized 22Rv1 xenograft model, with the long-term goal of developing a clinically translatable platform for minimally invasive detection and monitoring of tumor dissemination.

Methods

An incision was made in the upper back of 6-8 week-old male Nu/Nu mice (n=10), and two porous polycaprolactone scaffolds were implanted subcutaneously on either side of the incision. After vascularization was confirmed at 2 weeks, luciferase-tagged 22Rv1 prostate cancer cells were injected retro-orbitally. Two mice were sacrificed at each of the following timepoints: 0, 7, 14, 21, and 28 days. Scaffolds, axillary and inguinal lymph nodes, liver, lungs, adrenal gland, and femurs were harvested, fixed in 10% formalin and transferred to 70% ethanol in preparation for IHC staining. The presence of tumor cells within the scaffolds and the development of tumors were validated by immunohistochemistry (IHC) employing pan-cytokeratin (PAN-CK) antibodies (Figure 1).

Results

Implanted scaffolds have demonstrated vascularization at harvest. Scaffold and organ specimens from mice have been successfully harvested and preserved for histological and bioluminescence analysis. Ongoing work will quantify CTC presence within scaffolds, and correlate these findings with evidence of metastatic spread in harvested tissues.

Discussion

Our study presents a framework for investigating biomaterial scaffold-based CTC capture in a prostate cancer metastasis model. The implanted polycaprolactone scaffolds achieved vascularization as intended, and tissue specimens were successfully harvested and preserved for analysis. While histological and bioluminescence analyses are still pending, this approach demonstrates feasibility for studying CTC dynamics in prostate cancer metastasis.

Figure

Figure 1. Experimental workflow for biomaterial scaffold-based circulating tumor cell capture in prostate cancer xenograft model. Created with BioRender.