Biology subjects

Giancotti, F. G.

Publications and source records attributed to Giancotti, F. G..

4 recordsLinked to original sources

bioRxiv2023

Noncanonical Activity of Med4 as a Gatekeeper of Metastasis through Epigenetic Control of Integrin Signaling

Long term survival of breast cancer patients is limited due to recurrence from metastatic dormant cancer cells. However, the mechanisms by which these dormant breast cancer cells survive and awaken remain poorly understood. Our unbiased genome-scale genetic screen in mice identified Med4 as a novel cancer-cell intrinsic gatekeeper in metastatic reactivation. MED4 haploinsufficiency is prevalent in metastatic breast cancer patients and correlates with poorer prognosis. Syngeneic xenograft models revealed that Med4 enforces breast cancer dormancy. Contrary to the canonical function of the Mediator complex in activating gene expression, Med4 maintains 3D chromatin compaction and enhancer landscape, by preventing enhancer priming or activation through the suppression of H3K4me1 deposition. Med4 haploinsufficiency disrupts enhancer poise and reprograms the enhancer dynamics to facilitate extracellular matrix (ECM) gene expression and integrin-mediated mechano-transduction, driving metastatic growth. Our findings establish Med4 as a key regulator of cellular dormancy and a potential biomarker for high-risk metastatic relapse.

cancer biology↗

bioRxiv2023

STAT3 protects HSCs from intrinsic interferon signaling and loss of long-term blood-forming activity

STAT3 function in hematopoietic stem and progenitor cells (HSPCs) has been difficult to discern as Stat3 deficiency in the hematopoietic system induces systemic inflammation, which can impact HSPC activity. To address this, we established mixed bone marrow (BM) chimeric mice with CreER-mediated Stat3 deletion in 20% of the hematopoietic compartment. Stat3-deficient HSPCs had impaired hematopoietic activity and failed to undergo expansion in BM in contrast to Stat3-sufficient (CreER) controls. Single-cell RNA sequencing of Lin-ckit+Sca1+ BM cells revealed altered transcriptional responses in Stat3-deficient hematopoietic stem cells (HSCs) and multipotent progenitors, including intrinsic activation of cell cycle, stress response, and interferon signaling pathways. Consistent with their deregulation, Stat3-deficient Lin-ckit+Sca1+ cells accumulated {gamma}H2AX over time. Following secondary BM transplantation, Stat3-deficient HSPCs failed to reconstitute peripheral blood effectively, indicating a severe functional defect in the HSC compartment. Our results reveal essential roles for STAT3 in HSCs and suggest the potential for using targeted synthetic lethal approaches with STAT3 inhibition to remove defective or diseased HSPCs. Key PointsO_LISTAT3 is critical for hematopoietic activity and hematopoietic stem cell maintenance in non-inflammatory conditions C_LIO_LISTAT3 has a cell-intrinsic role in the suppression of interferon signaling and myeloid-skewed transcription in hematopoietic stem cells C_LI

immunology↗

bioRxiv2021

Transcriptional Inactivation of TP53 and the BMP Pathway Mediates Therapy-induced Dedifferentiation and Metastasis in Prostate Cancer

Unsupervised clustering and deconvolution analysis identifies a novel subtype of M-CRPC endowed with hybrid epithelial/mesenchymal (E/M) and luminal progenitor-like traits (Mesenchymal and Stem-like PC, MSPC). Analysis of patient datasets and mechanistic studies indicate that MSPC arises as a consequence of therapy-induced lineage plasticity. AR blockade instigates two separate and complementary processes: 1) transcriptional silencing of TP53 and hence acquisition of hybrid E/M and stem-like traits; and 2) inhibition of the BMP signaling, which promotes resistance to the pro-apoptotic and anti-proliferative effects of AR inhibition. The drug-tolerant prostate cancer cells generated through reprogramming are rescued by neuregulin and generate metastases in mice. Combined inhibition of HER2/3 and AR or mTORC1 exhibit efficacy in preclinical models of mixed ARPC/MSPC or MSPC, respectively. These results identify a novel subtype of M-CRPC, trace its origin to therapy-induced lineage plasticity, and reveal its dependency on HER2/3 signaling.

cancer biology↗

bioRxiv2020

Prostate Epithelial Genes Define Docetaxel-Sensitive Prostate Cancer Molecular Subtype

BACKGROUND & OBJECTIVESAnalysis of the transcriptomic landscape of prostate adenocarcinoma shows multidimensional gene expression variability. Understanding cancer transcriptome complexity can provide biological insight and therapeutic guidance. To avoid potential confounding factors, such as stromal contamination and stress-related material degradation, we utilized a set of genes expressed by prostate epithelial cells from single-cell transcriptome data of the human prostate gland. MATERIALS & METHODSAnalyzing publicly available bulk and single-cell RNA sequencing data, we defined 1,629 genes expressed by prostate epithelial cells. Consensus clustering and CIBERSORT deconvolution were used for class discovery and proportion estimate analysis. The Cancer Genome Atlas Prostate Adenocarcinoma (TCGA-PRAD) dataset served as a training set. The resulting clusters were analyzed in association with clinical, pathologic, and genomic characteristics and impact on survival. RESULTSTCGA-PRAD tumors were separated into four subtypes: A (30.0%), B (26.0%), C (14.7%), D (4.2%), and mixed (25.0%). Subtype A was characterized by low frequency of ETS-family fusions and high expression of KLK3, which encodes prostate-specific antigen (PSA). Subtype B showed the highest expression of ACP3, encoding PAP (prostatic acid phosphatase). Subtypes C and D were commonly associated with advanced T/N stages, high Gleason grades, and p53 or PIK3CA mutations. In silico drug-sensitivity screening suggested that subtype B is likely sensitive to docetaxel and paclitaxel. Serum PSA/PAP ratio was predictive of a radiographic response to docetaxel in metastatic castration-resistant prostate cancer patients. CONCLUSIONWe propose four prostate adenocarcinoma subtypes with distinct transcriptomic, genomic, and pathologic characteristics. PSA/PAP ratio in advanced cancer may aid in determining which patients would benefit from maximized androgen receptor inhibition or early use of antimicrotubule agents. Molecular subtypes and biomarkers must be validated in a prospective cohort study.

cancer biology↗