BackgroundVarious
forms of cancer immunotherapy are promising in overcoming the obstacles
posed by resistance to conventional chemo- and radiotherapy. Cancer
vaccines could serve as beneficial adjuncts to conventional therapies,
offering the potential for fine-tuning to reduce relapse and related
mortality. Continuing prior investigations, a therapeutic colorectal
cancer stem cell (CSC)-based vaccine was developed to explore whether
this vaccination could inhibit the formation and prolong survival rates
in a mouse model of colorectal cancer.MethodsCSCs
were enriched from the CT-26 cell line using sphere formation assay and
characterized by real-time q-PCR for stemness genes (Oct4, Sox2, and Nanog)
and tumorigenesis assay in syngeneic BALB/c mice. Different groups of
mice were intraperitoneally immunized with the CSC lysate-based vaccine,
the parental cell lysate-based vaccine, and control groups following
subcutaneous challenge with CT-26 cells. Beyond analyzing tumor growth
and survival rates, histological analysis of tumor tissues was conducted
using comprehensive hematoxylin and eosin (H&E) staining, and
antibody responses in vaccinated mice were evaluated by flow cytometry
and immunofluorescence.ResultsImmunization
of tumor-bearing mice with the CT-26 CSC lysate-based vaccine caused
delayed tumor formation, reduced tumor growth rate, and enhanced
survival rate compared to the control groups. The histological responses
observed in the lysate vaccination subgroups indicated a potent immune
response. Furthermore, flow cytometry and immunofluorescence analyses
demonstrated the production of anti-CSC and anti-parental cell
antibodies in mice immunized with CT-26 CSC and parental cell lysates.ConclusionThese
findings suggest that targeting CSCs using a CSC lysate-based vaccine
can stimulate cellular and humoral immunity and represent a novel
therapeutic approach to complement conventional antitumor therapies.