Primary colonospheres maintain stem cell-like key features after cryopreservation

Area of Science:

• Oncology
• Stem Cell Biology
• Biobanking and Cryopreservation

Background:

• Efficient biobanking of cancer stem cells (CSCs) is crucial for research and clinical applications.
• Limited data exists on cryopreservation's impact on CSC functional features.
• 3D spheroid structures can maintain CSC phenotype and genetic profiles.

Purpose of the Study:

• To evaluate the effects of cryopreservation on essential stem cell-like properties of CT-26 colonospheres.
• To assess the viability, self-renewal capacity, and tumorigenicity of cryopreserved colonospheres after thawing.

Main Methods:

• CT-26 colonospheres were cryopreserved in standard media and stored for 10 months.
• Real-time PCR and flow cytometry assessed stemness genes (SOX2, OCT4) and CSC surface biomarkers (CD133, CD166, DCLK1).
• Self-renewal capacity was evaluated via serial formation assays, and tumorigenicity was tested in immunocompetent mice.

Main Results:

• Post-thawed colonospheres exhibited high viability and maintained structural integrity and morphology.
• Cryopreserved colonospheres retained similar expression of SOX2 and OCT4 and showed elevated levels of CD133, CD166, and DCLK1.
• Both fresh and cryopreserved colonospheres demonstrated comparable self-renewal and tumorigenic capacities.

Conclusions:

• Cryopreservation is an effective strategy for storing CT-26 colonospheres, preserving key CSC features.
• This method provides a reliable repository of murine colorectal CSCs for future research projects.
• The findings support the use of cryopreserved colonospheres for retrospective analysis and clinical applications.