HCC-1806 Xenograft Model

The ACS estimates for 2019 US breast cancer cases are: Approximately 268,600 new invasive cancer cases, 62,930 cases of breast carcinoma in situ (CIS, non-invasive early stage) and 41,760 deaths attributed to breast cancer. Recent years have shown a slight increase in breast cancer rates (+0.4%/year). The HCC 1806 cell line was derived from the stage II (no lymph node metastasis) primary cancer of a 50yo Black female diagnosed with squamous cell breast cancer. These cells are acantholytic, meaning that they do not have intercellular connections such as desmosomes. Squamous cell breast carcinoma is very rare, about 0.1% of all breast cancers. The HCC 1806 model has been used in many breast cancer research studies. Martin et al. published a 2017 Breast Cancer Research article using HCC 1806 xenografts to investigate the combination therapy of gefitinib, an EGFR inhibitor, with Fingolimod, also known as FTY720, the sphingosine kinase (SphK) inhibitor. Results demonstrated a loss of T-cell immunoreactivity, increased apoptosis, and suppression of EGFR phosphorylation and Ki67. Data also suggested that efficacy in targeting IGFBP-3-dependent pathways in basal-like breast cancer can be predicted with IGFBP-3 and CD44 biomarkers. In 2018, Liu et al. published a Scientific Reports study using HCC1806 and other cell lines to evaluate mithramycin A, an Sp1 inhibitor, in triple negative breast cancer. Data showed treatment caused apoptosis and proliferation inhibition with downregulated KLF5. This supports the use of MIT in TNBC by inhibiting the Sp1/KLF5 axis. Lastly, a 2012 Neoplasia study (Volk-Draper et al.) used HCC1806 cells to identify basal TNBC markers and establish a subline, HCC1806-RR, that expressed RFP and Renilla luciferase. Results demonstrated sensitivity to paclitaxel (accompanied by pro-survival VEGF-A loop), bevacizumab, and taxane therapy. Data also suggested that the established subline HCC1806-RR was suitable for quantifying metastasis due to B-TNBC markers. The HCC 1806 cell line is used to create the CDX (Cell Line Derived Xenograft) HCC 1806 xenograft mouse model. The HCC 1806 xenograft model has been used to investigate triple negative breast cancer characteristics and treatments.

Basic Study Design

  1. HCC-1806 cells are maintained in exponential growth phase under aseptic conditions.
  2. Cells are trypsinized and cell count viability is determined using a trypan blue exclusion assay (98% of cell viability is required).  HCC-1806 cell suspension is adjusted to appropriate density.
  3. Each mouse is singly subcutaneously injected into the right flank with 106 cells in 100 µL of a Matrigel + HCC-1806 cell suspension.
  4. The injection sites are palpated up to three times weekly until tumors are established to an average size of 50-100 mm3 as measured via digital calipers.
  5. Animals are randomized into treatment groups. Administration of test compound is performed according to the pre-established treatment schedule.
  6. Mice weights are measured and recorded 3 times weekly; tumors are measured and recorded daily.
  7. End of study is reached when tumor size reaches 2,000 mmor the predetermined size limit per approved IACUC protocol.
  8. 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.