Biology subjects

Blenis, J.

Publications and source records attributed to Blenis, J..

7 recordsLinked to original sources

bioRxiv2025

Mineralocorticoid and glucocorticoid receptor interaction drives TGFB1-induced triple-negative breast cancer progression to metastasis

In triple-negative breast cancer (TNBC), p38 MAPK phosphorylates the glucocorticoid receptor (GR) at N-terminal Ser134 in response to cytokines, such as TGF{beta}1. Phospho-Ser134-GR (pSer134-GR) regulates genes that promote migratory/invasive behavior and altered metabolism. In addition to acting as ligands for GR, glucocorticoids also activate closely-related mineralocorticoid receptors (MR). Elevated MR activity via its physiological ligand aldosterone (aldo), mediates hypertension, inflammation and fibrosis. While GR/p-GR has been implicated in TNBC progression to metastasis, the contribution of MR remains unknown. The METABRIC dataset demonstrated significantly higher expression of MR transcripts in TNBC relative to luminal breast cancers. Further, high MR expression predicted worse overall survival in the KM-plotter database. We observed pSer134-GR- and p38-dependent association of cytoplasmic MR/p-GR complexes upon treatment of TNBC cells with TGF{beta}1, while nuclear MR-GR complexes predominated in response to dexamethasone (dex) and/or aldo. Cytoplasmic MR/p-GR complexes entered the nucleus within 4 hours. MR knockdown or inhibition with MR-selective antagonists (spironolactone, finerenone) significantly reduced aldo or TGF{beta}1-induced migratory and stemness properties. MR knockdown models exhibited reduced migration, attenuated stem cell expansion, and impaired metastasis to lungs following tail-vein injection, thereby phenocopying cells harboring phospho-mutant S134A-GR. MR activation by aldo or TGF{beta}1 transcriptionally upregulated both canonical MR-target genes (SGK1, ENaC1) and non-canonical target genes related to fibrosis (COL1A1, ICAM1 and CTGF). MR expression was essential for functionally intact p38 MAPK/p-Ser134-GR signaling downstream of TGF{beta}1 receptor activation. Our studies define a novel role of MR/p-GR complexes in regulation of TNBC cell migration, stemness potential, and metastasis. Pharmacological inhibition of MR with FDA-approved MR antagonists (MRAs) offers an exciting opportunity for improved clinical management of TNBC patients.

cancer biology↗

bioRxiv2025

Propionate metabolism dysregulation promotes drug-tolerant persister cell survival in non-small cell lung cancer

Recent studies show that genetic sequencing can not fully explain drug resistance in non-small cell lung cancer (NSCLC), suggesting undiscovered non-genetic mechanisms that can enable cancer cell survival. Propionate metabolism is the pathway by which odd-chain fatty acids, branched chain amino acids, and cholesterol are metabolized. We have previously shown that methylmalonic acid (MMA), a byproduct of propionate metabolism that accumulates when the pathway is disrupted, can activate epithelial-to-mesenchymal transition (EMT) in cell lines. But the clinical significance of propionate metabolism in cancer patients is not known. Here we show, for the first time, that propionate metabolism is dysregulated in patients with non-small cell lung cancer. MMA is elevated in lung tumors and in the serum of patients with metastatic NSCLC. Metabolism of cobalamin associated B (MMAB), a key regulatory gene of propionate metabolism, is downregulated in NSCLC and drug-tolerant persister cells, leading to MMA accumulation and EMT activation. We show that restoring expression of MMAB in NSCLC enhances targeted therapy and suppresses TGFB signaling. These findings reveal propionate metabolism dysregulation as a non-genetic mechanism of drug resistance and highlight propionate metabolism as a potential therapeutic target.

cancer biology↗

bioRxiv2025

Lysosome-dependent nutrient scavenging underliesstress adaptation during epithelial-to-mesenchymaltransition

Metastatic cancer cells invade tissue, overcome nutrient stress, and survive transit to distant sites. Many of the mechanisms that support these processes are incompatible with proliferation. This study defines cellular transition states in breast epithelial cells undergoing epithelial-mesenchymal transition (EMT) driven by ERK2 and TGF-{beta} signaling. EMT triggers robust endolysosomal system upregulation and metabolic adaptations that balance proliferative and invasive states. Surprisingly, invasive cells rely on scavenging via lysosomes and macropinocytosis to acquire amino acids, rather than plasma membrane transport, even in nutrient-rich conditions. Macropinocytosis increases intracellular amino acid storage, promoting survival during amino acid deprivation. This metabolic shift depends on c-MYC downregulation, an early EMT event. Reintroducing c-MYC suppresses the metabolic switch, endolysosomal induction, macropinocytosis, and the proliferation-to-migration transition. These findings reveal how cells dynamically balance proliferation and invasion, offering insights into transition states difficult to capture in models of breast cancer metastasis.

cell biology↗

bioRxiv2024

The Orphan G Protein-Coupled Receptor GPR52 is a Novel Regulator of Breast Cancer Multicellular Organization

Statement of SignificanceWe showed that loss of the orphan G protein-coupled receptor GPR52 in human breast cell lines leads to increased cell clustering, hybrid/partial EMT, and increased tumor burden in zebrafish. BackgroundG protein-coupled receptors (GPCRs) are the largest class of membrane-bound receptors that transmit critical signals from extracellular to intracellular spaces. Transcriptomic data of resected breast tumors show that low mRNA expression of orphan GPCR GPR52 correlates with reduced overall survival in patients with breast cancer, leading to the hypothesis that loss of GPR52 supports breast cancer progression. MethodsCRISPR-Cas9 was used to knockout GPR52 in the human triple-negative breast cancer (TNBC) cell lines MDA-MB-468 and MDA-MB-231, and in the non-cancerous breast epithelial cell line MCF10A. 2D and 3D in vitro studies, electron microscopy, Matrigel culture, and a zebrafish xenograft model were used to assess the morphology and behavior of GPR52 KO cells. RNA-sequencing and proteomic analyses were also conducted on these cell lines, and transcriptomic data from The Cancer Genome Atlas (TCGA) database were used to compare GPR52-null and wild-type (WT) signatures in breast cancer. ResultsLoss of GPR52 was found to be associated with increased cell-cell interaction in 2D cultures, altered 3D spheroid morphology, and increased propensity to organize and invade collectively in Matrigel. Furthermore, GPR52 loss was associated with features of EMT in MDA-MB-468 cells, and zebrafish injected with GPR52 KO cells developed a greater total cancer area than those injected with control cells. RNA sequencing and proteomic analyses of GPR52-null breast cancer cells revealed an increased cAMP signaling signature. Consistently, we found that treatment of wild-type (WT) cells with forskolin, which stimulates the production of cAMP, induces phenotypic changes associated with GPR52 loss, and inhibition of cAMP production rescued some GPR52 KO phenotypes. ConclusionGPR52 is an orphan GPCR and its role in cancer progression has not been previously characterized. We found that GPR52 loss in breast cancer cells can lead to increased cell clustering, collective invasion, and EMT in vitro. These are features of increased cancer aggression. Our results reveal that GPR52 loss is a potential mechanism by which breast cancer progression may occur and support the investigation of GPR52 agonism as a therapeutic option for breast cancer. O_FIG O_LINKSMALLFIG WIDTH=169 HEIGHT=200 SRC="FIGDIR/small/604482v2_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@8b0f55org.highwire.dtl.DTLVardef@19bd139org.highwire.dtl.DTLVardef@c52117org.highwire.dtl.DTLVardef@1ffa2bd_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG

cancer biology↗

bioRxiv2023

LKB1 suppresses growth and promotes the internalization of EGFR through the PIKFYVE lipid kinase

The tumor suppressor LKB1 is a serine/threonine protein kinase that is frequently mutated in human lung adenocarcinoma (LUAD). LKB1 regulates a complex signaling network that is known to control cell polarity and metabolism; however, the pathways that mediate the tumor suppressive activity of LKB1 are incompletely defined. To identify mechanisms of LKB1- mediated growth suppression we developed a spheroid-based cell culture assay to study LKB1- dependent growth. Using this assay, along with genome-wide CRISPR screens and validation with orthogonal methods, we discovered that LKB1 suppresses growth, in part, by activating the PIKFYVE lipid kinase, which promotes the internalization of wild-type EGFR. Our findings reveal a new mechanism of regulation of EGFR, which may have implications for the treatment of LKB1-mutant LUAD.

cancer biology↗

bioRxiv2022

A global atlas of substrate specificities for the human serine/threonine kinome

Protein phosphorylation is one of the most widespread post-translational modifications in biology. With the advent of mass spectrometry-based phosphoproteomics, more than 200,000 sites of serine and threonine phosphorylation have been reported, of which several thousand have been associated with human diseases and biological processes. For the vast majority of phosphorylation events, it is not yet known which of the more than 300 protein Ser/Thr kinases encoded in the human genome is responsible. Here, we utilize synthetic peptide libraries to profile the substrate sequence specificity of nearly every functional human Ser/Thr kinase. Viewed in its entirety, the substrate specificity of the kinome was substantially more diverse than expected and was driven extensively by negative selectivity. Our kinome-wide dataset was used to computationally annotate and identify the most likely protein kinases for every reported phosphorylation site in the human Ser/Thr phosphoproteome. For the small minority of phosphosites where the protein kinases involved have been previously identified, our predictions were in excellent agreement. When this approach was applied to examine the signaling response of tissues and cell lines to hormones, growth factors, targeted inhibitors, and environmental or genetic perturbations, it revealed unexpected insights into pathway complexity and compensation. Overall, these studies reveal the full extent of substrate specificity of the human Ser/Thr kinome, illuminate cellular signaling responses, and provide a rich resource to link unannotated phosphorylation events to biological pathways.

systems biology↗

bioRxiv2020

Age-induced methylmalonic acid accumulation promotes tumor progression and aggressiveness

From age 65 onwards, the risk of cancer incidence and associated mortality is substantially higher1-3. Nonetheless, our understanding of the complex relationship between age and cancer is still in its infancy4. For decades, the link has largely been attributed to increased exposure time to mutagens in older individuals. However, this view does not account for the well-established role of diet, exercise and small molecules that target the pace of metabolic aging5-8. Here, we show that metabolic alterations that occur with age can render a systemic environment favorable to progression and aggressiveness of tumors. Specifically, we show that methylmalonic acid (MMA), a by-product of propionate metabolism, is significantly up-regulated in the serum of older people, and functions as a mediator of tumor progression. We traced this to the induction of SOX4 and a consequent transcriptional reprogramming that can endow cancer cells with aggressive properties. Thus, accumulation of MMA represents a novel link between aging and cancer progression, implicating MMA as a novel therapeutic target for advanced carcinomas.

cancer biology↗