Biology subjects

Valencia Salazar, L. E.

Publications and source records attributed to Valencia Salazar, L. E..

3 recordsLinked to original sources

bioRxiv2026

Enforced ZFP281 expression delays breast cancer initiation and can provide lifelong protection against breast cancer metastasis

Breast cancer metastatic reactivation and its links to mammary development are largely unknown. Here, using conditional knockout and overexpression in normal and HER2+ mammary glands, we show that the dormancy regulator ZFP281 promotes branching and dissemination while suppressing growth, and its overexpression can even override HER2-driven cancer initiation. Notably, while ZFP281 does not limit HER2-driven early dissemination, it constrains DCC plasticity, confining cells to a dormant mesenchymal/hybrid-like state and effectively suppressing metastasis throughout the mouse lifespan. ZFP281 is induced by estrogen, progesterone, and glucocorticoid signaling, and RNA sequencing of early lesions revealed that it regulates glutathione metabolism and ferroptosis, potentially supporting fitness during dormancy, while repressing angiogenesis, Th17-like inflammation, innate immune genes, and pro-inflammatory programs that might otherwise trigger awakening. Integrating these findings with human data, we show that DCIS and IBC (invasive breast cancer) lesions that later relapse are selectively enriched for ZFP281-regulated M-like and dormancy signatures and, after pregnancy, depleted for a ZFP281-induced stress-autophagy module, indicating that erosion or imbalance of these programs marks lesions that seed DCCs with higher reactivation potential. We propose that ZFP281 acts as a hormone-regulated dormancy gatekeeper that uncouples dissemination from growth, enforcing a metabolically fit, angiogenesis-low, immune-evasive dormant state in breast DCCs, thereby shaping the timing of metastatic relapse and potentially exploitable for durable prevention of metastasis. STATEMENT OF SIGNIFICANCEZFP281, a hormone-regulated dormancy gatekeeper, uncouples dissemination from growth and constrains DCCs into long-term arrest, defining human gene signatures that distinguish dormancy-prone from awakening-prone lesions and predict breast cancer relapse dynamics.

cancer biology↗

bioRxiv2025

The E2F4 transcriptional repressor is a key mechanistic regulator of colon cancer resistance to irinotecan (CPT-11).

Background. Colorectal carcinomas (CRCs) are seldom eradicated by cytotoxic chemotherapy. Cancer cells with stem-like functional properties, often referred to as "cancer stem cells" (CSCs), display preferential resistance to several anti-tumor agents used in cancer chemotherapy, but the molecular mechanisms underpinning their selective survival remain only partially understood. Methods. In this study, we used Transcription Factor Target Genes (TFTG) enrichment analysis to identify transcriptional regulators (activators or repressors) that undergo preferential activation by chemotherapy in CRC cells with a "bottom-of-the-crypt" phenotype (EPCAM+/CD44+/CD166+; CSC-enriched) as compared to CRC cells with a "top-of-the-crypt" phenotype (EPCAM+/CD44neg/CD166neg; CSC-depleted). The two cell populations were purified in parallel by fluorescence-activated cell sorting (FACS) from a patient-derived xenograft (PDX) line representative of a moderately differentiated human CRC, following in vivo chemotherapy with irinotecan (CPT-11). The transcriptional regulators identified as differentially activated were tested for differential expression in normal vs. cancer tissues, and in cell populations enriched in stem/progenitor cell-types as compared to differentiated lineages (goblet cells, enterocytes) in the mouse colon epithelium. Finally, the top candidate was tested for mechanistic contribution to drug-resistance by selective down-regulation using short-hairpin RNAs (shRNAs). Results. Our analysis identified E2F4 and TFDP1, two core components of the DREAM transcriptional repression complex, as transcriptional modulators preferentially activated by irinotecan in EPCAM+/CD44+/CD166+ as compared to EPCAM+/CD44neg/CD166neg cancer cells. The expression levels of both genes (E2F4, TFDP1) were found up-regulated in CRCs as compared to human normal colon tissues, and in a sub-population of mouse colon epithelial cells enriched in stem/progenitor elements (Epcam+/Cd44+/Cd66alow/Kitneg) as compared to other sub-populations enriched in either goblet cells (Epcam+/Cd44+/Cd66alow/Kit+) or enterocytes (Epcam+/Cd44neg/Cd66ahigh). Most importantly, E2F4 down-regulation using shRNAs dramatically enhanced the sensitivity of human CRCs to in vivo treatment with irinotecan, across three independent PDX models. Conclusions. Our data identified E2F4 and the DREAM repressor complex as critical regulators of human CRC resistance to irinotecan, and as candidate targets for the development of chemo-sensitizing agents.

cancer biology↗

bioRxiv2022

Phenotypic dissection of epithelial lineages and therapeutic manipulation of differentiation programs in human Adenoid Cystic Carcinomas

Adenoid Cystic Carcinoma (ACC) is a rare and aggressive form of salivary gland cancer, characterized by the co-existence within tumor tissues of two distinct populations of malignant cells, phenotypically similar to the myoepithelial and ductal lineages of normal salivary glands. Using a novel computational approach for single-cell RNA-seq analysis, we identified two cell-surface markers (CD49f, KIT) that enable the differential purification of myoepithelial-like (CD49fhigh/KITneg) and ductal-like (CD49flow/KIT+) cells from ACC patient derived xenografts (PDX). Using prospective xeno-transplantation experiments, we demonstrate that myoepithelial-like cells act as progenitors of ductal-like cells. Using three-dimensional (3D) organoid cultures, we demonstrate that agonists of retinoic acid (RA) signaling promote differentiation of myoepithelial-like cells into ductal-like cells, while inhibitors of RA signaling selectively kill ductal-like cells. Finally, we demonstrate that BMS493, an inverse agonist of RA signaling, can be successfully leveraged for the in vivo treatment of human ACCs.

cancer biology↗