A Phase I/II Study of Active Immunotherapy With Cancer Stem Cells Vaccine for Colorectal Cancer

Overview

Most studies of cancer stem cells (CSC) involve the inoculation of cells from human tumors into immunosuppressed mice, preventing an assessment on the immunologic interactions and effects of CSCs. In this study, the investigators examined the vaccination effects produced by CSC-enriched populations from histologically distinct murine tumors after their inoculation into different syngeneic immunocompetent hosts. Enriched CSCs were immunogenic and more effective as an antigen source than unselected tumor cells in inducing protective antitumor immunity.Immune sera from CSC-vaccinated hosts contained high levels of IgG which bound to CSCs, resulting in CSC lysis in the presence of complement.CTLs generated from peripheral blood mononuclear cells or splenocytes harvested from CSC-vaccinated hosts were capable of killing CSCs in vitro. Mechanistic investigations established that CSC-primed antibodies and T cells were capable of selective targeting CSCs and conferring anti-tumor immunity.

To assess the feasibility of generating CSC-loaded DC vaccines for clinical use, the investigators will harvest peripheral blood and tumor specimen from patients with colorectal cancer. The investigators will purify T, B cells and generate DCs from the PBMCs of the colorectal cancer patient.On the other hand, investigators will isolate ALDHhigh and ALDHlow tumor cells from the tumor specimen of the colorectal cancer patient using a similar protocol as investigators reported . Aim 1: To demonstrate, in vitro, the relative cellular anti-colorectal cancer CSC immunity induced by colorectal cancer CSC-DC primed cytotoxic T cells. Aim 2: To determine, in vitro, specific binding and lysis of colorectal cancer CSCs by antibodies produced by purified B cells from PBMCs stimulated with colorectal cancer CSC-DC.