Cancer cell metastasis has been recognized as one hallmark of malignant tumor progression; thus, measuring the motility of cells, especially tumor cell migration, is important for evaluating the therapeutic effects of anti-tumor drugs.

Here, we used a paper-based cell migration platform to separate and isolate cells according to their distinct motility. A multi-layer cells-in-gels-in-paper(CEGEP) Stack was assembled. Only a small portion of DU 145 prostate cancer cells seeded inthe middle layer could successfully migrate into the top and bottom layers of the stack, showingheterogeneous motility. The cells with distinct migration were isolated for further analysis.

Quantitative PCR assay results demonstrated that cells with higher migration potential had increasedexpression of the ALDH1A1, SRY (sex-determining region Y)-box 2, NANOG, and octamer-bindingTranscription 4.

Increased doxorubicin tolerance was also observed in cells that migrated through the CEGEP layers. In summary, the separation and characterization of prostate cancer cell subtype can beachieved by using the multi-layer CiGiP cell migration platform.Cell migration is a fundamental cellular function implicated in many biological and pathological processes, such as embryonic morphogenesis, wound repair, and cancer invasion.

Cancer cell

Cancer cell metastasis has been recognized as one hallmark of malignant tumor progressio. Metastatic relapse or distant progression is one of the most frequent causes of death from cancer, which clearly emphasizes the urgent need to develop strategies for the prevention of metastasis. 

In  separating and isolating a subpopulation of cells by their motility was achieved by using the multi-layer CiGiP cell invasion platform. A five-layer CiGiP platform was constructed. The cell-seeding layer was sandwiched in the middle tier. After seven days of culture, only a small fraction of cells invaded through the paper sheets, showing stronger motility than cells that did not invade.

The qPCR results showed elevated expression of the putative prostate CSC biomarkers, ALDH1A1, SOX2, NANOG, and OCT4, in cells with higher motility. To the best of our knowledge, this is the first separating and characterizing different tumor cells according to their invasion potential.Moreover, the correlation between higher motility and expression of putative prostate CSC biomarkers was demonstrated.

There is an urgent need to develop strategies for the prevention ofmetastasis. The CEGEP cell invasion platform shown in this study could be used to screenproteins that promote metastasis, thereby allowing the development of therapeutic strategies for targeting CSCs.