miR-132-3p regulates antibody-mediated complement-dependent cytotoxicity in colon cancer cells by directly targeting CD55.

Autor: Fan, Yu, Liao, Juan, Wang, Yu, Wang, Zhu, Zheng, Hong, Wang, Yanping
Předmět:
Zdroj: Clinical & Experimental Immunology; Jan2023, Vol. 211 Issue 1, p57-67, 11p, 1 Diagram, 1 Chart, 4 Graphs
Abstrakt: The overexpression of membrane-bound complement regulatory proteins (mCRPs) on tumour cells helps them survive complement attacks by suppressing antibody-mediated complement-dependent cytotoxicity (CDC). Consequently, mCRP overexpression limits monoclonal antibody drug immune efficacy. CD55, an mCRP, plays an important role in inhibiting antibody-mediated CDC. However, the mechanisms regulating CD55 expression in tumour cells remain unclear. Here, the aim was to explore CD55-targeting miRNAs. We previously constructed an in vitro model comprising cancer cell lines expressing α-gal and serum containing natural antibodies against α-gal and complement. This was used to simulate antibody-mediated CDC in colon cancer cells. We screened microRNAs that directly target CD55 using LoVo and Ls-174T colon cell lines, which express CD55 at low and high levels, respectively. miR-132-3p expression was dramatically lower in Ls-174T cells than in LoVo cells. miR-132-3p overexpression or inhibition transcriptionally regulated CD55 expression by specifically targeting its mRNA 3ʹ-untranslated regions. Further, miR-132-3p modulation regulated colon cancer cell sensitivity to antibody-mediated CDC through C5a release and C5b-9 deposition. Moreover, miR-132-3p expression was significantly reduced, whereas CD55 expression was increased, in colon cancer tissues compared to levels in adjacent normal tissues. CD55 protein levels were negatively correlated with miR-132-3p expression in colon cancer tissues. Our results indicate that miR-132-3p regulates colon cancer cell sensitivity to antibody-mediated CDC by directly targeting CD55. In addition, incubating the LoVo human tumour cell line, stably transfected with the xenoantigen α-gal, with human serum containing natural antibodies comprises a stable and cheap in vitro model to explore the mechanisms underlying antibody-mediated CDC. miR-132-3p regulates CD55 expression by directly targeting the 3ʹ-UTR of CD55, leading to changes in cell sensitivity to Ab-mediated CDC through the release of C5a and deposition of C5b-9. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index