DLGAP1-AS2–Mediated Phosphatidic Acid Synthesis Activates YAP Signaling and Confers Chemoresistance in Squamous Cell Carcinoma

Abstract

Squamous cell carcinomas (SCC) constitute a group of human malignancies that originate from the squamous epithelium. Most SCC patients experience treatment failure and relapse and have a poor prognosis due to de novo and acquired resistance to first-line chemotherapeutic agents. To identify chemoresistance mechanisms and explore novel targets for chemosensitization, we performed whole-transcriptome sequencing of paired resistant and parental SCC cells. We identified DLGAP1 antisense RNA 2 (D-AS2) as a crucial noncoding RNA that contributes to chemoresistance in SCC. Mechanistically, D-AS2 affected chromatin accessibility around the histone mark H3K27ac of FAM3 metabolism regulating signaling molecule D (FAM3D), reducing FAM3D mRNA transcription and extracellular protein secretion. FAM3D interacted with the Gαi-coupled G protein-coupled receptors (GPCRs) formyl peptide receptor 1 (FPR1) and FPR2 to suppress phospholipase D (PLD) activity, and reduced FAM3D increased PLD signaling. Moreover, activated PLD promoted phosphatidic acid (PA) production and subsequent nuclear translocation of yes-associated protein (YAP). Accordingly, in vivo administration of a D-AS2-targeting antisense oligonucleotide sensitized SCC to cisplatin treatment. In summary, this study shows that D-AS2/FAM3D-mediated PLD/PA lipid signaling is essential for SCC chemoresistance, suggesting D-AS2 can be targeted to sensitize SCC to cytotoxic chemotherapeutic agents.

Long noncoding RNA DLGAP1-AS2 promotes tumorigenesis and metastasis by regulating the Trim21/ELOA/LHPP axis in colorectal cancer

“…Recent studies also reported the upregulation and prognostic value of DLGAP1-AS2 in several cancer types. Similar tumor-promoting functions have also been observed in multiple cancer types, including rectal cancer [ 19 – 26 ]. For example, a recent study conducted by Zeng et al reported that DLGAP1-AS2 promotes the radioresistance in rectal cancer stem cells through regulating the E2F1-CD151 axis [ 27 ].…”

m6A Demethylase FTO Stabilizes LINK-A to Exert Oncogenic Roles via MCM3-Mediated Cell Cycle Progression and HIF-1α Activation

“…Moreover, we detected the protein level of FTO in the parental and chemoresistant ESCC cell lines previously established. 27 The results showed that FTO protein expression was upregulated in both chemoresistant cell lines compared with their preprint (which was not certified by peer review) is the author/funder. All rights reserved.…”

“…Then, to further identified FTO-regulated lncRNAs, we depleted or overexpressed FTO in two ESCC cell lines and detected the expression levels of 14 annotated ncRNAs that were previously shown to be significantly upregulated in chemoresistant ESCC cell lines compared with the parental cell lines. 27 The expression of four ncRNAs (TTLL3, LINC00663, PRSS30P and CETN4P) were too low to be detected by real-time quantitative PCR (RT-qPCR).…”

“…The cell proliferation rate and cell survival were assessed as previously described. 27 For the inhibitor (YC-1 (HY-14927; MedChemExpress) and digoxin (HY-B1049;…”

“…RNA pulldown and RIP assays were performed as previously reported. 27 Negative control IgG (#2729; Cell Signaling Technology) and anti-MCM3 (ab272877; Abcam; 1:100), anti-IGF2BP2 (ab128175; Abcam; 1:1000) and anti-m 6 A (202003; Synaptic Systems; 1:100) antibodies were used in the RIP assay. MS analysis of proteins precipitated by the LINK-A sense and antisense strands was performed by Shanghai Applied Protein Technology Co., Ltd (Shanghai, China).…”