Abstract 7290: Novel plasmid-based screening method for cervical cancer

Abstract

Abstract Introduction: Alabama (AL) is tied for third-highest incidence rate and has second-highest death rate of cervical cancer as of 2020. Globally, cervical cancer has the fourth-highest incidence among cancers in women; 90% of deaths from cervical cancer in 2020 occurred in low- and middle-income (LMIC) countries. Inhibitor of differentiation/DNA binding 1 (Id1) expression correlates with tumorigenesis, clinical grade/stage, and aggressiveness of cervical cancer. Thus, Id1 expression could be exploited in novel screening approaches that aim to improve survival rates of cervical cancer in LMIC and clinically underserved settings. As a first step in developing an Id1-based screening approach, these preclinical studies utilized a plasmid that induces expression of a secreted reporter enzyme (secreted embryonic alkaline phosphatase, SEAP), controlled by the Id1 promoter sequence (pId1-SEAP). These studies examined relationships between Id1 expression and kinetics of reporter expression following plasmid transfection to detect human cervical cancer cells. Methods and Results: To confirm the relevance of Id1 as a target in cervical cancer, immunohistochemical staining for Id1 was performed on a human cervical cancer tissue microarray. Western blotting was performed to determine Id1 expression in human cervical cancer cell lines (HeLa, SiHa, CaSki). Optimal transfection conditions with pId1-SEAP were determined experimentally for each line, and then media was sampled through a 48-hour period post-transfection to quantify reporter SEAP expression. Immunohistochemical stain for Id1 showed that early stage and late stage human cervical cancer tissues expressed significantly (p < 0.05) higher levels of Id1 compared to normal tissues, with stain optical density values being 3e5±1e5 for early and late stage compared to 3e4±3e4 for normal tissues (early stage p=0.0001, late stage p=0.0002). Western blot for Id1 in HeLa, SiHa, and CaSki lines showed that all three positively expressed Id1, with Beta-actin-normalized expression values of 0.78±0.12, 1.12±0.05, and 0.76±0.08, respectively. The cell lines transfected with pId1-SEAP expressed SEAP at rates significantly higher than control cells, with the highest rates of production seen during the 36-48-hour post-transfection period. Rates of SEAP production (counts/hour) during this time period were 1e4±3e3 (p=0.0278), 8e2±1e2 (p=0.0834), and 3e2±5e1 (p=0.0683) for transfected HeLa, SiHa, and CaSki cells, respectively. Conclusions: The pId1-SEAP system enabled sensitive detection of cervical cancer cells. These preliminary data support future studies evaluating the in vivo performance of the system in preclinical models of early stage cervical cancer. Further development of this approach could enable sensitive and reliable detection of cervical cancer during early stages when treatment is most effective. Citation Format: Abbigael Eli, Yolanda Hartman, Benjamin B. Kasten, Rebecca Arend, Jason Warram. Novel plasmid-based screening method for cervical cancer [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 7290.