Biology subjects

Rajan, A. R.

Publications and source records attributed to Rajan, A. R..

3 recordsLinked to original sources

bioRxiv2025

ECD, a novel androgen receptor target promotes prostate cancer tumorigenesis by regulating glycolysis

Androgen receptor (AR)-mediated signaling is essential for PC tumorigenesis. In the TCGA database we observed a positive correlation between ECD and AR expression. Consistently, Dihydrotestosterone (DHT) treatment of PC cell lines increased ECD mRNA and protein levels, and AR knockdown (KD) reduced ECD expression. Bioinformatic analysis predicted three consensus androgen response elements in the ECD promoter, and DHT treatment increased AR occupancy at the ECD promoter, and enhanced ECD promoter activity. Enzalutamide treatment decreased ECD levels, and ECD knockout (KO) in PC cells reduced oncogenic traits, suggesting a functional role of ECD to maintain PC oncogenesis. ECD mRNA and protein are overexpressed in PC patient tissues, and its overexpression predicts shorter survival. Overexpression of ECD in PC cell lines enhanced the oncogenic traits in vitro and developed faster and larger highly proliferative xenograft tumors. RNA-seq analysis of mouse tumors revealed an increase in mRNA levels of several glycolytic genes. ECD associates with mRNA of key glycolytic genes and is required for their stability, consistent with our recent demonstration of ECD is an RNA binding protein. Higher glucose uptake and glycolysis was seen upon ECD overexpression in PC cells. Together, we demonstrate the role of a novel AR target gene ECD in PC tumorigenesis.

cancer biology↗

bioRxiv2025

ECD co-operates with ERBB2 to promote tumorigenesis through upregulation of unfolded protein response and glycolysis

The ecdysoneless (ECD) mRNA and protein are overexpressed in breast cancer (BC), and its overexpression correlates with poor prognosis and short patient survival, particularly in ERBB2/HER2-positive BC. This study investigates the co-operative oncogenic mechanism of ECD and ERBB2 by deriving transgenic mice overexpressing ECD and/or ERBB2 (huHER2) in mammary epithelium under MMTV promoter, as well as human mammary immortal epithelial cell lines (hMECs) overexpressing ECD and/or ERBB2. While huHER2Tg mice developed more homogenous solid nodular carcinomas, double transgenic mice (ECD;huHER2Tg) developed heterogenous and histologically aggressive mammary tumors with basal-like phenotype and epithelial mesenchymal transition (EMT) features, like ECDTg tumors, resembling more to patient tumors. Importantly, transcriptomic profile of ECD;huHER2Tg tumors revealed upregulation of two major oncogenic pathways, unfolded protein response (UPR) and glycolysis. Similarly, hMECs expressing both ECD and ERBB2 as compared to single gene expressing cells showed increase in oncogenic traits, and RNA-seq analysis showed a significant upregulation of glycolysis and UPR pathways. ECD is an RNA binding protein, and directly associates with three key glycolytic enzymes (LDHA, PKM2 and HK2) and mRNA of a major UPR regulated gene GRP78, that results in increased mRNA stability. Lastly, we show an increase in glucose uptake and enhanced glycolytic rate in ECD+ERBB2-overexpressing cells as compared to ECD- or ERBB2-overexpressing hMECs. Taken together, our findings support a co-operative role of ECD and ERBB2 in oncogenesis by enhancing two major oncogenic pathways, UPR and glycolysis. SignificanceThis study provides mechanistic insights that overexpression of ECD in ERBB2+ breast cancer patients correlates with shorter patient survival, by identifying direct ECD binding to mRNAs for UPR and glycolysis pathways.

cancer biology↗

bioRxiv2025

ECD functions as a novel RNA-binding protein to regulate mRNA splicing

Human ecdysoneless protein (ECD) plays an essential role in regulating cell cycle progression and cell survival. ECD has previously been implicated in RNA splicing through its association with spliceosomal proteins. Here, using EMSA, fluorescence polarization assays, and mutational analysis, we demonstrate that ECD directly binds to RNA. Enhanced CLIP-seq analysis identified a broad repertoire of mRNAs bound to ECD in cells. RNA-seq analyses revealed that ECD depletion leads to widespread splicing aberrations and altered gene expression. ECD binding to RNAs was enriched near splice sites, and a substantial fraction of ECD-bound transcripts exhibited splicing defects upon ECD depletion. ECD associates with and stabilizes the U5 snRNP complex specific proteins. While depletion of ECD reduced the levels of key U5-specifc proteins, these proteins exhibited an increased association with the R2TP complex in knockout cells. Notably, we found ECD to directly bind to U5 snRNA, and an RNA binding defective mutant of ECD ({Delta}135-148) failed to rescue the reduced levels of U5-specific proteins or the proliferation defect induced by ECD depletion. Collectively, these findings demonstrate that ECD binds to RNAs, including the U5 snRNA, and that RNA-binding is required for ECD to stabilize the U5 snRNP and for cellular functions. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=80 SRC="FIGDIR/small/634785v4_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@f5aa4forg.highwire.dtl.DTLVardef@80606borg.highwire.dtl.DTLVardef@3a4c8eorg.highwire.dtl.DTLVardef@1780b0f_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗