ECC1 Xenograft Model

ECC1 Xenograft Model

Endometrial cancer is a cancer subtype beginning in the uterus and is sometimes referred to as uterine cancer. Women over the age of 55 are the group at highest risk for developing endometrial cancer. Common symptoms include abnormal vaginal bleeding but oftentimes this cancer is asymptomatic. Treatments often include surgical resection, radiation, chemotherapy and hormone therapy. The ECC1 cell line was established by P.G. Satyaswaroop from a patient, 39 years of age, female, and diagnosed with endometrium adenocarcinoma. The ECC1 has been used in many endometrial cancer research studies. Mo et al. (Biology of Reproduction, 2006) released a study characterizing the ECC1 line and summarized that ECC1 cells have luminal epithelium characteristics, maintain hormone responsiveness (via estrogen, progesterone, and androgen receptors), express p160 steroid receptor coactivators (i.e. NCOA1-3). Cells also express hyaluronate receptor CD44, SPP1, and CD55 which are thought to be involved in implantation. A 2014 Clinical Cancer Research paper by Weigelt et al. used ECC1 cells to investigate the role of PI3K pathways in endometrial cancers, as they often harbor mutations including in PI3KCA, PI3KR1, KRAS and PTEN. Results demonstrated that PI3KCA-mutant cells were sensitive to GDC-0941, a pan-class I PI3K inhibitor, and that PTEN-mutant cells were sensitive to Temsirolimus, an allosteric mTOR inhibitor. Furthermore, p110β inhibition only demonstrated a negative viability impact when p110α was simultaneously inhibited. Finally, the International Journal of Molecular Sciences released a study (Want et al., 2014) using the ECC1 model to evaluate the role of platelet-derived growth factor (PDGF)-D in endometrial cancer. Using RT-PCR, western blotting, MTT assays, colony formation assays, proliferation assays, invasion assays and immunohistochemical staining, it was demonstrated that overexpression of PDGF-D in endometrial cells supports and accelerates tumor growth and invasion in a MMP2 and MMP9-mediated mechanism. PDGF-D overexpression also induced epithelial to mesenchymal transition (EMT); these results were confirmed using in vivo xenografts. The ECC1 cell line is used to create the CDX (Cell Line Derived Xenograft) ECC1 xenograft mouse model. The ECC1 xenograft model has been used to investigate endometrial cancer characteristics and therapies.

Basic Study Design

  1. ECC1 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 (98-99% of cell viability is required).  ECC1 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- ECC1 cell suspension.
  4. The injection sites are palpated up to three times weekly until tumors are established to an average size of 50-150 mm3 as measured by 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 mm3 or 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