Page 402 - IJB-9-3

International Journal of Bioprinting Bioprinting of a multicellular model

two models were mainly focused on cell proliferation, checkpoint pathway is an important mechanism of tumor
apoptosis, cell cycle regulation, and drug resistance. immune escape. The PD-L1 in tumor cells and the TME
Therefore, it is reasonable to use more physiological models binds to PD-1, restricting the host immune response. The
for subsequent functional verification and drug screening. expression of PD-L1 is dependent on tumor-associated M2
Compared with colorectal cancer cells in sandwich macrophages in the TME, which promotes the apoptosis of
culture, the differences in upregulated genes of colorectal antitumor T cells and the growth of colorectal cancer cells.
Tyrosine kinase inhibitors are small-molecule antitumor
cancer cells in the 3D printing-S were mainly concentrated drugs that can cross the cell membrane and block the
in cell composition, followed by biological process, and
there was little difference in molecular function. signaling pathway of tumor cell growth and division.
Resistance to tyrosine kinase inhibitors produces a pro-
Different types of 3D culture models have varying cancer effect . KEGG enrichment analysis suggested that
[46]
effects on the proliferation and signal communication the upregulation of the PD-1/PD-L1 checkpoint pathway
of colorectal cancer cells. The 3D bioprinted model has and EGFR receptor tyrosine kinase inhibitor resistance
a unique spatial structure. KEGG enrichment analysis pathway in colorectal cancer cells in the 3D printing-M
showed that focal adhesion and adhesion junctions were was reflected in our 3D bioprinted multicellular co-culture
the most significant pathways enriched by downregulated model to a certain extent. The influence of the TME on tumor
gene in the 3D printing-S and sandwich culture groups . cells has been verified at the transcriptomic level. The hub
[43]
The results suggest that the same bio-ink material and differential genes between the two models (3D printing-S
colorectal cancer cells, the 3D bioprinted model, and the and 3D printing-M) include IL1B, FCGR2A, FCGR3A,
sandwich model have different cell-cell communication CYBB, SPI1, CCL2, and other functional genes related to
and adhesion mechanisms. The functions of the hub immune response, immune regulation, and inflammatory
differential genes between the two models were mainly response [47,48] . The hub differential genes between the two
focused on signal transduction, immune response, cell models (3D printing-S and 3D printing-M) also included
proliferation, apoptosis, lipid metabolism, etc. Cell cycle genes such as ITGAM, ITGB2, and other genes related
regulation and signal transduction were also significantly to cell conduction and cell adhesion [49,50] . By analyzing
different in 3D culture of different types. hub genes, we found that in the constructed co-culture
In this study, we explored the influence of tumor- model of tumor cell-mesenchymal cells, the influence
associated macrophages M2 and endothelial cells on of mesenchymal cells on tumor cells was implicated in
colorectal cancer cells. The multicellular model constructed biological processes such as cell growth, cell metabolism,
by the concentric axis dual-nozzle 3D bioprinter is protein modification, signal regulation, intracellular signal
conducive to the mechanistic study of the influence of the transduction, and intercellular communication. The TME
TME on tumor cells. To analyze the effect of mesenchymal composed of intermediate cells in the 3D printing-M may
cells on the tumor cell signaling pathway, we screened for have an impact on colorectal cancer cells, which reveals
important hub differential genes. Compared with colorectal the potential value of the 3D printing-M in the functional
cancer cells in the 3D printing-S, the upregulated DEGs in study of the effect of TME on tumor cells.
the 3D printing-M were mostly concentrated in biological There are also great differences between 2D culture
processes. In terms of cell composition, the differences models and 3D printing-S, and between 3D printing-S and
between them were small, considering that both were 3D printing-M in the experimental results of antitumor
3D bioprinted models. The difference between the two drug screening. The IC values for 5-FU in 2D culture
50
models lies in the influence of the microenvironment group and 3D printing-S group were 12.79 µM and
on interstitial cells. KEGG enrichment analysis of the 31.13 µM, respectively. The IC value of the 3D printing-S
50
enrichment pathways of DEGs in biological functions of group was three times that of the 2D culture group, which
colorectal cancer cells in 3D printing-M group and 3D was more resistant to drugs. For oxaliplatin, the IC of 2D
50
printing-S group showed that in tumor cell-mesenchymal culture group and 3D printing-S group was 0.80 µM and
cell co-culture model, the effects of mesenchymal cells on 26.79 µM, respectively. The concentration of 0.80 µM in
colorectal cancer cells involve biological processes such the 2D culture model has a significant inhibitory effect
as cell growth, cell metabolism, protein modification, on colorectal cancer cells, which is obviously not in line
signal regulation, intracellular signal transduction, and with the actual situation of human body. In the drug
intercellular communication. Pathways with significant screening experiments of three chemotherapeutic drugs,
enrichment of upregulated DEGs include the PD-1/PD-L1 the IC measured by the 3D printing-S group was closer
50
checkpoint pathway and the EGFR receptor tyrosine to the effective blood drug concentration in the human
kinase inhibitor resistance pathway [44,45] . The PD-1/PD-L1 body, indicating that the 3D bioprinted colorectal cancer

Volume 9 Issue 3 (2023) 394 https://doi.org/10.18063/ijb.694