Biology subjects

Kim, A. C.

Publications and source records attributed to Kim, A. C..

4 recordsLinked to original sources

bioRxiv2025

Upregulation of GREB1 in colorectal cancer ovarian metastases may be a potential therapeutic target

IntroductionClassification of ovarian metastases (OM) in colorectal cancer (CRC) as peritoneal metastasis (PM) remains controversial. OM demonstrate resistance to systemic therapy, suggesting distinct molecular tumorigenesis. Gene expression profiling and transcriptomic analysis were performed to distinguish OM, PM, and primary CRC (pCRC) and identify potential therapeutic targets. MethodsRNA sequencing data were obtained from the Total Cancer Care database. After filtering out low-expressed genes, raw counts of retained genes were normalized in trimmed mean of M-values and then log2-transformed. Genes with a |Log2FC|>0.58 and adjusted p-value <0.05 were considered dysregulated. In silico motif enrichment analysis of estrogen receptor 1 (ESR1) on growth regulating estrogen receptor binding 1 (GREB1) was conducted. ResultsThere were 115 patients with tissue from OM (n=6), PM (n=4), and pCRC (n=105). Among upregulated genes, LAMC3, SCUBE1, and GREB1 had the highest differential expression in OM compared to PM, and PEG3, C7, and GREB1 had the highest differential expression in OM compared to pCRC (all p<0.001). GREB1 was upregulated in OM compared to PM and pCRC. There are two estrogen response element (ERE) sites within the promoter region of GREB1. ESR1 transcription factor was shown to bind to these ERE (p<0.001). ConclusionsTranscriptomic analysis demonstrated clear molecular distinction between OM, PM and pCRC. We identified upregulation of GREB1 in OM compared to PM and pCRC. GREB1 contains both ERE and ESR1 in the upstream promoter regions implying potential upstream transcription regulation mediated by ESR1. GREB1 may represent a novel, hormonal target in treatment of OM in CRC.

cancer biology↗

bioRxiv2025

TWIST1 mediated transcriptional activation of SPON2 drives colorectal peritoneal metastasis through activation of cancer-associated fibroblast signaling network

Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the second leading cause of cancer-related mortality in the United States. Peritoneal metastasis (PM), a malignant dissemination within the peritoneal cavity, affects approximately 20% of CRC patients and accounts for 25-35% of stage IV cases. CRC PM is associated with dismal outcomes, with a median overall survival of only 16 months on systemic chemotherapy and an almost 0% five-year survival rate, largely due to frequent treatment resistance and limited therapeutic options. Despite advances in understanding CRC metastasis, the molecular mechanisms driving CRC PM remain poorly defined. CRC heterogeneity is classified into four Consensus Molecular Subtypes (CMS1-4), with CRC PM tumors predominantly exhibiting the CMS4 signature--characterized by stromal enrichment, high mesenchymal gene expression, and enhanced cellular plasticity--features linked to aggressive disease progression and resistance to standard chemotherapy. In this study, we identify TWIST1, a basic helix-loop-helix transcription factor, as significantly upregulated in CRC PM. We establish TWIST1-SPON2 as a novel transcriptional axis driving CRC PM tumorigenesis, mediating tumor-stroma interactions between tumor epithelium and cancer-associated fibroblasts (CAFs). Additionally, we identify SPP1, secreted by CAFs, as an upstream regulator of the TWIST1-SPON2 cascade via AKT activation in tumor cells. This newly defined SPP1-TWIST1-SPON2 signaling circuit plays a pivotal role in shaping the tumor microenvironment and promoting CRC PM progression. The findings establish the SPP1-TWIST1-SPON2 axis as a potential biomarker and a promising therapeutic target in CRC PM. Keyword: Colorectal cancer, peritoneal metastasis, epithelial-mesenchymal transition, cancer-associated fibroblast

cancer biology↗

bioRxiv2024

Single-cell resolution spatial analysis of antigen-presenting cancer-associated fibroblast niches

Recent studies have identified a unique subtype of cancer-associated fibroblasts (CAFs) termed antigen-presenting CAFs (apCAFs), which remain the least understood CAF subtype. To gain a comprehensive understanding of the origin and function apCAFs, we construct a fibroblast molecular atlas across 14 types of solid tumors. Our integration study unexpectedly reveals two distinct apCAF lineages present in most cancer types: one associated with mesothelial-like cells and the other with fibrocytes. Using a high-resolution single-cell spatial imaging platform, we characterize the spatial niches of these apCAF lineages. We find that mesothelial-like apCAFs are located near cancer cells, while fibrocyte-like apCAFs are associated with tertiary lymphoid structures. Additionally, we discover that both apCAF lineages can up-regulate the secreted protein SPP1, which facilitates primary tumor formation and peritoneal metastasis. Taken together, this study offers an unprecedented resolution in analyzing apCAF lineages and their spatial niches.

cancer biology↗

bioRxiv2023

PBRM-1/PBAF-regulated genes in a multipotent progenitor

The Caenorhabditis elegans somatic gonadal precursors (SGPs) are multipotent progenitors that generate all somatic cells of the adult reproductive system. The two SGPs originate in the mesodermal layer and are born through a division that produces one SGP and one head mesodermal cell (hmc). One hmc terminally differentiates and the other dies by programmed cell death. The PBAF chromatin remodeling complex promotes the multipotent SGP fate. Complete loss of PBAF causes lethality, so we used a combination of Cre/lox recombination and GFP nanobody-directed protein degradation to eliminate PBRM-1, the signature subunit of the PBAF complex, from 83 mesodermal cells, including SGPs, body muscles, and the hmc. We used RNA sequencing to identify genes acting downstream of PBAF in these cells and identified 1955 transcripts that were significantly differentially expressed between pbrm-1(-) and pbrm-1(+) in the mesoderm of L1 larvae. We found that genes involved in muscle cell function were overrepresented; most of these genes had lower expression in the absence of PBRM-1, suggesting that PBAF promotes muscle differentiation. Among the differentially expressed genes were 125 genes that are normally expressed at higher levels in SGP vs. hmc and positively regulated by pbrm-1 and 53 that are normally expressed at higher levels in hmc vs. SGP and are negatively regulated by pbrm-1; these are candidate regulators of the SGP/hmc fate decision. We validated one candidate gene using a fluorescent reporter; the hsp-12.3 reporter was derepressed in SGPs in pbrm-1 mutants, suggesting that hsp-12.3 expression is normally repressed by pbrm-1 in SGPs.

developmental biology↗