Abstract 772: Investigation of gender disparity in liver tumor formation using a hydrodynamic tail vein injection mouse model
Authors: Bernal Araceli , McLaughlin Morgana , Tiwari Ankur , Cigarroa Francisco , Sun LuZhe 
Published: March 2024

Abstract
The incidence of hepatocellular carcinoma (HCC), the major form of liver cancer, is 4 times higher in men than in women. This gender disparity is difficult to study since it is believed to be multifactorial, due in part to differences in risk factors, behaviors, and hormones. The liver is a sexually dimorphic organ that is extremely susceptible to interactions with estrogens and androgens. Estrogen has been proven to have a protective effect against HCC with a demonstrable gender-related hormonal effect on the growth of HCC, though the underlying mechanisms are not fully understood. The hydrodynamic tail vein injection (HTVI) mouse model allows for the induction of liver tumors in the host. Eliminating the social and behavioral aspects of the gender disparity will allow us to determine what role estrogen plays in tumor development. In our study, a gender disparity in tumor development was observed between 6-week-old male and female FVB/NJ mice injected via HTVI of plasmids expressing c-MET, a mutated beta-catenin (b-Cat) and Sleeping Beauty transposon. HTVI of a Luciferase and Sleeping Beauty transposon expressing plasmid showed no significant difference in photon flux by bioluminescence imaging between male and female mice 24 hours after injection. When imaging was repeated one week after injection, the photon flux reduced by an order of magnitude in both male and female mice with the female mice showing more uniform reduction than the male mice. Similar luciferase gene copy number was detected in the liver tissue of male and female mice. These data suggest that there appears to be no gender difference in the transient expression and stable integration of the transfected plasmid. Plasma alpha-fetoprotein (AFP) was used to monitor tumor formation in the mice that were injected with c-MET and b-Cat without luciferase as luciferase is immunogenic. The male mice had significantly higher AFP levels at 3.5 weeks, 8 weeks, and 12 weeks post-injection than the female mice. At termination, the liver weight confirmed that female mice had much lower tumor burden than the males. We are currently using quantitative PCR to confirm similar copy number of exogenous c-MET and b-Cat inserted in the tumor cell genome and using RT-qPCR and Western blotting to determine whether the transgene expression is different in tumors from male and female mice. To determine whether estrogen played a role in preventing tumor development and progression in female mice, six-week-old male and ovariectomized female mice have been injected with the same oncogene plasmid combination plus the sleeping beauty. Interestingly, AFP levels between male and ovariectomized female mice were comparable when measured at 3 weeks. We will present our findings at the meeting.
Citation Format: Araceli Bernal, Morgana McLaughlin, Ankur Tiwari, Francisco Cigarroa, LuZhe Sun. Investigation of gender disparity in liver tumor formation using a hydrodynamic tail vein injection mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 772.