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International Journal of Bioprinting Bioprinted vascular tumor model

under unified culture conditions to ensure stability and relevance of drug response assays. The ability of the model
consistency. This approach allowed us to establish a robust to recapitulate key features of tumor–vascular interactions
and reproducible system; however, we acknowledge that it makes it a powerful tool for evaluating anti-cancer
may not fully capture the complexity of the native TME, drugs under conditions that more closely mimic in vivo
particularly the diverse phenotypes of tumor-associated tumor physiology.
fibroblasts. Therefore, this model represents a proof-of-
concept framework, which we plan to refine in future studies 4. Conclusion
by incorporating primary cells to enhance physiological In this study, we successfully developed a multiscale
relevance. Taken together, these results demonstrate vascularized tumor model by integrating coaxial
that the multiscale vascularized tumor model not only
achieves spatial integration of vascular networks and tumor bioprinting, inkjet printing, and FDM techniques. This
spheroids but also supports dynamic interactions between model was designed to precisely replicate the dynamic
the two components. The formation of microvessels is characteristics of the TME, including the mechanical
regulated by the synergistic interaction between fibroblasts and physiological properties of double-layered vessels,
and endothelial cells, while the tumor spheroids influence the size controllability of tumor spheroids, and the radial
vascular morphology through paracrine signaling, forming distribution of microvascular networks. Our results
a bidirectional, biomimetic microenvironment. This model demonstrate that the formation of microvessels relies
thus serves as a highly representative in vitro platform for on the synergistic interactions between fibroblasts and
investigating tumor–vascular crosstalk and evaluating anti- endothelial cells, while the tumor spheroids secrete
angiogenic therapies. angiogenic factors that induce directional vascular
sprouting. This bidirectional crosstalk highlights the
3.5. Influence of the vascular network on tumor model’s capability to reproduce critical tumor–vascular
behavior and drug evaluation interactions. Moreover, drug testing using this platform
To assess the physiological relevance and drug evaluation revealed a concentration-dependent inhibitory effect of
potential of the multiscale vascularized tumor model, we paclitaxel on tumor progression, validating the model’s
selected paclitaxel as a model chemotherapeutic agent and potential for preclinical pharmacological screening.
investigated the regulatory effects of the vascular network Despite these achievements, some limitations remain—
on tumor cell proliferation, metastasis, and drug sensitivity. including the complexity of fabrication procedures, the
Quantitative real-time PCR (qRT-PCR) analysis revealed lack of immune microenvironment simulation, and
that, in the presence of a vascular network, the expression challenges in maintaining long-term stability—and the
levels of metastasis-related genes (CD44, CXCL12, absence of quantitative assessment of endothelial barrier
MMP2, N-cadherin) and pro-survival genes (CD40) were function (e.g., using molecular permeability markers).
significantly upregulated compared to those in models Future work will aim to enhance the model’s biomimicry by
lacking vascularization (Figure 6A). The simultaneous incorporating immune components, regulating dynamic
upregulation of CD44 and MMP2 suggests that the vascular oxygen gradients, and incorporating advanced metrics
microenvironment may promote an invasive tumor (e.g., fluorescent dextran diffusion or Trans-Epithelial
phenotype by enhancing ECM remodeling. Further dose- Electrical Resistance [TEER]) to rigorously evaluate
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dependent experiments with paclitaxel (0.03–0.1 μg/mL) physiological transport and endothelial barrier function.
revealed a progressive suppression of these gene expressions Additionally, combining this platform with patient-derived
(Figure 6B). Specifically, at 0.1 μg/mL paclitaxel, MMP2 tumor organoids may enable personalized drug sensitivity
and CD44 expression levels decreased to 32% and 28% of testing, while single-cell omics technologies could further
the control group, respectively, indicating that the drug elucidate the molecular networks underlying tumor-–
effectively inhibited the metastatic potential of tumor cells vascular–immune interactions. Taken together, this study
by disrupting microtubule stability. In addition, Figure S2, provides a versatile and physiologically relevant in vitro
Supporting Information demonstrated that the diameter of platform for the investigation of tumor progression, drug
tumor spheres expanded from ~500 μm on Day 1 to ~750 response, and mechanisms of therapy resistance, with broad
μm on Day 7, whereas the tumor spheres in the drug-treated applications in cancer research and precision medicine.
group (0.1 µg/mL paclitaxel) exhibited a diameter of only
~650 μm on Day 7, indicating that paclitaxel treatment Acknowledgments
significantly inhibited the volumetric growth of tumor
spheres. These findings confirm that the incorporation of The authors would like to express our gratitude to Tao
a vascular network within the tumor model significantly Ding, Wenqi Wei, and Weihao Teng for their valuable
modulates tumor cell behavior and enhances the biological assistance in the preparation of bioink.

Volume 11 Issue 4 (2025) 388 doi: 10.36922/IJB025180180