Transcriptomic analysis of tetraspanins in colorectal cancer

Abstract Introduction: Transmembrane proteins and their overexpression have been highly involved in malignancies. In particular, Tetraspanins (TSPANs)—a family of four-span transmembrane proteins—have been proposed as “master organizers” of multi-molecular membrane complexes by associating with specific partners and thus contributed to the progression of many cancer types. To date, transcriptomic analysis of all human TSPANs in colorectal cancer (CRC) has remained unclear. Here, we focused on utilizing next-generation RNA sequencing (RNA-Seq) to explore the expression level of TSPANs in primary tumor tissues of CRC, which is a complex disease and the second cause of cancer mortality worldwide. Experimental Procedures: Resected primary tumor tissues of CRC were collected from 100 patients along with the written informed consents. Later, total RNA was extracted from all frozen patient tissues. RNA-Seq of those RNA samples was next done before the transcriptomic analysis of TSPANs in CRC was performed. Immunofluorescence (IF) and Immunohistochemistry (IHC) stains were also employed to confirm the target protein expression in formalin-fixed paraffin-embedded tissue (FFPE) slides from CRC patients. Results: As a result of transcriptomic analysis of TSPANs in CRC tissues, among 33 human TSPANs, the high expression levels (transcript per million above the average of all TSPANs) of TSPAN1, TSPAN8, TSPAN24, TSPAN29 and TSPAN30 were observed in the patient-derived CRC tissues. Notably, the expression level of TSPAN8 was comparable with that of EPCAM, which is a well-known tumor marker. Moreover, the high expression of TSPAN8 protein could be clearly observed in both IF and IHC-stained FFPE slides from CRC patients. Our result highlights the possible relevance of these overexpressed TSPANs in CRC development. Conclusions: This study is the first RNA-Seq-based transcriptomic analysis of all human TSPANs in CRC. Our finding suggests the significant overexpression of particular TSPANs, especially TSPAN8, in CRC. Further analyses will be beneficial for translational research in CRC. The overexpression of TSPANs may suggest a framework to further explore diagnostic, prognostic, and predictive surface biomarkers, therapeutic targets, and other applications for CRC. Citation Format: Thanawat Suwatthanarak, Pariyada Tanjak, Amphun Chaiboonchoe, Onchira Acharayothin, Kullanist Thanormjit, Tharathorn Suwatthanarak, Watsaphon Tangkullayanone, Manop Pithukpakorn, Vitoon Chinswangwatanakul. Transcriptomic analysis of tetraspanins in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2241.