Abstract 3209: The expression of SLC7A11 transporter in lung and pancreatic cancer tissues at different stages of development

Abstract

Abstract Purpose: The purpose is to investigate the expression of the SLC7A11 transporter in human biopsy samples from patients with lung or pancreatic cancer at different stages of development. The SLC7A11 is a membrane antiporter highly specific for cystine. It is a major transporter for the uptake of cystine in exchange of intracellular glutamate. It plays a role in the growth and progression of cancers because they need extracellular cystine for growth. The expression of SLC7A11 was compared between normal and malignant tissues. Methods: Lung and pancreatic tissue array slides were purchased from US Biomax, Inc. Pancreatic samples were categorized into adenocarcinoma, normal and adjacent to cancer tissues. Lung cancer samples were categorized into: adenocarcinoma or squamous cell carcinoma, and normal tissue. The slides were hydrated with a series of washes using xylene and graded alcohols. The tissue arrays underwent blocking of endogenous peroxidase and albumin. The tissue arrays were processed with a primary antibody (1:500) dilution of a rabbit polyclonal antibody against SLC7A11, and a secondary antibody (1:3000) dilution of goat anti-rabbit conjugated to horseradish peroxidase (HRP). The slides were counterstained with hematoxylin and images were taken with the EVOS® FL Cell Imaging System. The software ImageJ was used to determine proportion of stained cells. The staining intensity was determined by comparing the samples to their negative control supplied on the tissue arrays. The immune-reactive score (IRS) was calculated as SI x PP and it ranged from 0 to 12. An IRS within 0-3 indicated no, or low expression, 4-7 medium expression and 8-12 high expression. The distribution of the IRS score frequency in the different stages was compared to that of the normal tissues and compared using the chi square test for trend. Results: The SLC7A11 is significantly overexpressed on all cancer tissues compared to normal tissues or adjacent to cancer tissues. Pancreatic and lung adenocarcinomas as well as lung squamous cells carcinomas have significantly different distributions of IRS score staining for SLC7A11 compared to normal tissues. However, there is no significant difference between the different cancer stages and the distributions of the IRS staining for SLC7A11. Conclusion: The results indicate that expression of the SLC7A11 transporter is significantly overexpressed in cancer compared to the normal tissues, but there is no significant difference between the expression levels of SLC7A11 at different stages of lung or pancreatic cancer. Citation Format: Jonathan A. Moreno, Maria P. Lambros. The expression of SLC7A11 transporter in lung and pancreatic cancer tissues at different stages of development. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3209. doi:10.1158/1538-7445.AM2015-3209