Improved mouse orthotopic bladder cancer model quantification using GFP image analysis

LB-81

The mouse orthotopic model has been a valuable tool for the study of the mechanisms involved in superficial bladder cancer. Unfortunately, there have been shortcomings with the current models in regards to therapeutic studies, namely the inability to practically and accurately verify the presence of tumor before treatment and to accurately and objectively measure the resulting effects after treatment is complete. In addition, tumor samples are often used for histological analysis preventing further molecular analysis. We propose a new modification to the current model as well as an objective method to precisely measure tumors using image analysis. KU-7/GFP human bladder cancer cells were transurethally implanted into female nude mice and were assigned to a control group or Dox (Doxorubicin) treatment group seven days after cell inoculation. Prior to intravesiscal Dox treatment, the bladders were exposed and images of the bladder were captured for tumor verification and GFP analysis. Fourteen days after cell inoculatuion the bladders were exposed and images were captured for GFP analysis, animals were sacrificed and bladders were collected for histological confirmation. Bladder tumo measurements for GFP distribution and integrated density were determined by image analysis and tumor presence was confirmed by gross examination and Hematoxylin and Eosin staining. There was a 2.9 fold increase in tumor size for the control group vs. a 3.4 fold decrease in tumor size for the Dox treatment group. Additionally there was a 3.2 fold increase in tumor integrated density for the control group compared to 3.4 fold decrease in the Dox treatment group. The product of area and integrated density at 7 days and 14 days are (8.69 and 69.04) and (61.67 and 7.44) for control and Dox treatment groups, respectively. These findings demonstrate that this modified model can effectively monitor the presence of tumors before any treatment is applied as well as follow up of tumor progression. This eliminates the need for histological analysis thus saving the tumor for other analysis and therefore providing a powerful research tool.