HCT-15 Xenograft Model
There are over 200,000 cases in the United States of colorectal cancer annually. This disease primarily occurs in people over 60 years of age, which is why colonoscopies (and follow-up biopsies where appropriate) are recommended for cancer screening. Most cases of colon cancer begin as small benign adenomatous polyps in the final part of the digestive tract that mutate and develop into cancer. The HCT15 cell line was isolated from a patient diagnosed with Dukes’ type C colon adenocarcinoma. HCT15 cells have since been used as a colon cancer model in many studies. In 1982, Dexter et al. released a Cancer Research study using the HCT15 xenograft model to characterize the effects of N,N-dimethylformamide (DMF) and N-methyl-formamide (NMF) on colon cancer. Results demonstrated that the compounds caused tumor growth inhibition mediated by the metabolism of DMF to NMF, but this was accompanied by significant hepatic toxicity. Ehrig et al. published an article in the Journal of Translational Medicine (2013) demonstrating tumor growth inhibition upon a single i.v. injection of GLV-1h68, an oncolytic replication- competent vaccinia virus (VACV). The group used HCT15 murine xenografts and also demonstrated an inflammation-mediated immune response as evidenced by an increased in immune-related antigens as well as increased NK cell and macrophage infiltration. These results have positive implications for the potential of virotherapy. Lastly, a 2017 Monoclonal Antibodies in Immunodiagnosis and Immunotherapy (Kaneko et al.) article used the HCT15 colon adenocarcinoma xenograft model to study the effect of a podocalyxin (PODXL) antibody on tumors. PODXL is typically overexpressed and the group produced a chimeric human-mouse antibody PcMab-47 targeting PODXL and treated xenografted mice; the antibody exhibited antitumor activity supporting its potential use for antibody therapy in PODXL over-expressing tumors. The HCT15 cell line is used to create the CDX (Cell Line Derived Xenograft) HCT15 xenograft mouse model. The HCT15 xenograft model has been used to evaluate anticancer therapies for colon cancer including virotherapy, antibody therapy, and the Phellodendron amurense extract nexrutine (NX).
Basic Study Design
- HCT15 cells are maintained in exponential growth phase under aseptic conditions.
- Cells are trypsinized and cell count viability is determined using a trypan blue exclusion assay (98% of cell viability is required). HCT15 cell suspension is adjusted to appropriate density.
- Each mouse is subcutaneously injected into the right flank with 106 cells in 100 µL of a Matrigel- HCT15 cell suspension.
- The injection sites are palpated up to three times weekly until tumors are established to an average size of 50-150 mm3 as measured via digital calipers.
- Animals are randomized into treatment groups. Administration of test compound is performed according to the pre-established treatment schedule.
- Mice weights are measured and recorded 3 times weekly; tumors are measured and recorded daily.
- End of study is reached when tumor size reaches 2,000 mm3 or the predetermined size limit per approved IACUC protocol.
- Final necropsy and tissue collections are performed for appropriate downstream analysis. Tumors are excised, weighed and documented by digital imaging. Tumors and tissues can be stabilized in RNAlater, snap frozen in LN2 or prepared for histology.