I am trying to establish an ovarian cancer preclinical model through peritoneal injection into C57BL/6 mice.
The parental ID8 p53-/- cell line was modified through lentiviral infection in order to express OVA peptide and GFP-luciferase. We injected 5·10e^6 cells per mice.
In day 40 after injection we did not get any tumor in any of the mice.
Couple things.... the ID8 cells you generated are expressing 3+ new proteins, each on their own can potentially slow tumor growth by increasing the immunogenicity of the tumor (especially for OVA). Knowing this, you should have included a set of mice with the parental ID8 p53 -/- along side as a positive control.
If you failed to see tumors in your positive control group, you either didn't inject as many cells as you thought (i.e. counting errors, substantial cell death) or you were working with a different cell line.
The original parental ID8 cell line grows very slowly (8-10 weeks), and the ID8-OVA cells are sooooo much slower (12-15).
Check these papers out.
The original ID8 p53-/- paper
Walton, J. et al. CRISPR/Cas9-Mediated Trp53 and Brca2 Knockout to Generate Improved Murine Models of Ovarian High-Grade Serous Carcinoma. Cancer Res 76, 6118–6129 (2016).
ID8-Luc2
Baert, T. et al. The dark side of ID8-Luc2: pitfalls for luciferase tagged murine models for ovarian cancer. J Immunother Cancer 3, 57 (2015).
ID8-GFP
Lee, W. et al. Neutrophils facilitate ovarian cancer premetastatic niche formation in the omentum. J Exp Med 216, 176–194 (2018).