5. Conclusion
A simple and cost-effective method for the generation of tumor spheroids
has been reported. It consists of enveloping individual tumor cells in
agarose hydrogels (with 0.25 or 0.125% weight percentage) blended with
0.02% collagen, where agarose reproduces the biomechanical features of
the ECM, while collagen provides the anchoring sites for the membrane
proteins. The growth of tumoroids deriving from three breast cancer
cells lines was analyzed and compared. Interestingly, one cell line,
MDA-MB-231 did not form spheroids in any of the conditions employed,
while the other two lines, MCF-7 and MDA-MD-361displayed a quite similar
behavior.
The variation of the agarose amount affected the physical and mechanical
features of the resulting hydrogel and the growth of spheroids. Indeed
the stiffer the hydrogel, more compact and slightly smaller the
tumoroids resulted. Therefore, depending on the type of tumoroids to be
prepared and studied, the hydrogel composition can be easily tuned. The
growth of the spheroids was monitored up to 2 weeks, and the qualitative
analysis of their viability evidenced few dead cells only after 14 days.
Preliminary drug testing studies with cisplatin show that the blended
hydrogels allow following the response of the spheroids to the drug
administration. This aspect makes the system potentially useful for
routine drug screening.
Finally, the degradability of the hydrogels upon enzymatic treatment was
demonstrated, leading to complete recovery of tumoroids in the case of
the softest hydrogels, while to a partial recovery in the hydrogel with
0.25% agarose. The possibility to recover the spheroids is of a
paramount importance as it enables further biomolecular studies with the
collected samples.