Biology subjects

Tavazoie, S. F.

Publications and source records attributed to Tavazoie, S. F..

10 recordsLinked to original sources

bioRxiv2026

Colorectal cancers with distinct metastatic potential trigger divergent early T cell responses

Colorectal cancer (CRC) remains a leading cause of cancer mortality, with most cases refractory to immunotherapy. Distinguishing tumor-induced from steady-state mucosal T cell responses has been a critical barrier to understanding antitumor immunity in CRC. Using orthotopic transplantation of CRC organoids with and without metastatic potential, combined with temporal T cell fate-mapping, we show that non-metastatic tumors elicit early recruitment of CD8{beta} and CD4 T cells that acquired cytotoxic and Th1-like programs, whereas pro-metastatic tumors induce a naive-like, hypoactivated state. Tumor-infiltrating CD4+ T cells underwent clonal expansion, including clones recognizing microbial and dietary antigens. T cells in physical contact with tumor cells, identified by uLIPSTIC, were enriched for expanded and cytotoxic clones. Fate-mapped T cells from non-metastatic tumors suppressed tumor growth in an IFN-{gamma}-dependent manner, whereas pro-metastatic tumor-derived T cells failed to do so. Mechanistically, pro-metastatic tumors downregulated MHCII, and Ciita targeting in non-metastatic organoids reduced CD4 clonal expansion and led to tumor progression. Together, these findings define divergent early T cell trajectories associated with CRC metastatic potential, indicating that ineffective local immune engagement precedes metastatic dissemination.

immunology↗

bioRxiv2025

Tumor Genotype Dictates Mitochondrial and Immune Vulnerabilities in Liver Cancer

Although oncogenic alterations influence tumor metabolism, how they impose distinct metabolic programs within a shared tissue context remains poorly defined. Here, we developed a rapid mitochondrial profiling platform to compare metabolites and proteins in genetic models of primary liver cancer (PLC). Analyses of six genetically distinct PLCs revealed that mitochondrial energy metabolism is largely dictated by oncogene identity. Kras-driven tumors required creatine metabolism to buffer energy demands during early tumorigenesis, whereas c-MYC-driven tumors relied on oxidative phosphorylation. Among c-MYC-driven PLCs, Pten-deficient tumors accumulated mitochondrial phosphoethanolamine, a precursor for phosphatidylethanolamine (PE) synthesis. Inhibition of PE synthesis selectively impaired the growth of Pten-deficient tumors and extended survival, in part through enhanced infiltration of CD8 T cells and sensitization to TNF-mediated cytotoxicity. Mechanistically, loss of PE elevated surface TNF receptor 2 (TNFR2), promoting TNF signaling and pro-inflammatory response. These findings uncover genotype-specific mitochondrial metabolic liabilities and establish PE synthesis as a tumor-intrinsic mechanism of immune evasion in PLC.

cancer biology↗

bioRxiv2024

Neuronal substance-P drives breast cancer growth and metastasis via an extracellular RNA/TLR7 axis

Increased tumour innervation is associated with adverse survival outcomes in multiple cancers1-4. To better understand the mechanisms underlying this, we studied the impact of innervation on breast cancer metastatic progression. Metastatic mammary tumours of mice were substantially more innervated than non-metastatic isogenic tumours. Three dimensional co-cultures and in vivo models revealed that sensory dorsal root ganglion (DRG) neurons enhanced the growth, invasion, and systemic dissemination of cancer cells--thereby driving breast cancer metastasis. By in vitro screening of neuropeptides known to be secreted by DRG neurons, we identified substance-P (SP) as a mediator of these pro-metastatic functions. Neuronal SP signaled through tumoural tachykinin receptors (TACR1) to drive single-stranded RNA (ssRNA) secretion from cancer cells. Extracellular RNA acted on tumoural TLR7 receptors to activate an autocrine pro-metastatic gene expression program. In support of these findings, patient tumours with increased SP expression exhibited higher rates of lymph node metastasis. Additionally, this SP/ssRNA induced Tlr7 gene expression signature associated with reduced breast cancer survival outcomes in two independent patient cohorts. Finally, therapeutic targeting of this neuro-cancer axis with the TACR1 antagonist aprepitant, an approved anti-nausea drug, suppressed breast cancer metastasis in multiple mouse models. Our findings reveal multiple aspects of metastatic progression to be regulated by neurons via a therapeutically targetable neuropeptide/extracellular RNA sensing axis.

cancer biology↗

bioRxiv2023

Inter-organellar nucleic acid communication by a mitochondrial tRNA regulates nuclear metabolic transcription

Efficient communication between mitochondria and the nucleus underlies homoeostatic metabolic control, though the involved mitochondrial factors and their mechanisms are poorly defined. Here, we report the surprising detection of multiple mitochondrial-derived transfer RNAs (mito-tRNAs) within the nuclei of human cells. Focused studies of nuclear-transported mito-tRNA-asparagine (mtAsn) revealed that its cognate charging enzyme (NARS2) is also present in the nucleus. MtAsn promoted interaction of NARS2 with histone deacetylase 2 (HDAC2), and repressed HDAC2 association with specific chromatin loci. Perturbation of this axis using antisense oligonucleotides promoted nucleotide biogenesis and enhanced breast cancer growth, and RNA and nascent transcript sequencing demonstrated specific alterations in the transcription of nuclear genes. These findings uncover nucleic-acid mediated communication between two organelles and the existence of a machinery for nuclear gene regulation by a mito-tRNA that restricts tumor growth through metabolic control. HighlightsO_LIMultiple mitochondrial-derived tRNAs are detected in human cell nuclei C_LIO_LIMtAsn promotes binding between NARS2 and HDAC2 C_LIO_LIMetabolic alterations driven by mtAsn impact cell proliferation C_LIO_LIMtAsn inhibition releases HDAC2 to bind and transcriptionally regulate multiple nuclear genes C_LI

molecular biology↗

bioRxiv2022

Apolipoprotein E2 Promotes Melanoma Growth, Metastasis, and Protein Synthesis via the LRP1 Receptor

The secreted lipid transporter apolipoprotein E (APOE) plays important roles in atherosclerosis and Alzheimers disease and has been implicated as a suppressor of melanoma progression. APOE germline genotype predicts human melanoma outcomes, as APOE4 and APOE2 allele carriers exhibit increased versus reduced melanoma survival, respectively, relative to APOE3 homozygotes. While the APOE4 variant was recently shown to suppress melanoma progression by enhancing anti-tumor immunity, the melanoma cell-intrinsic effects of APOE variants on cancer progression remain poorly characterized. By using a genetically engineered mouse model, we show that human germline APOE genetic variants differentially modulate melanoma growth and metastasis in a melanoma LRP1 receptor-dependent manner. We identify protein synthesis as a tumor cell-intrinsic process differentially modulated by APOE variants, with APOE2 surprisingly promoting translation via LRP1. Our findings reveal a gain-of-function role for the APOE2 variant in melanoma progression, raising important implications for other diseases impacted by APOE genetics. SignificanceOur work reveals that germline APOE variants differentially impact genetically initiated melanoma progression, with APOE2 acting as a promoter of tumor growth, metastasis, and a cell-intrinsic process--protein synthesis. These findings may aid in predicting patient outcomes and may partly explain the protective effect of APOE2 in Alzheimers disease.

cancer biology↗

bioRxiv2021

Therapeutic targeting of SLC6A8 creatine transporter inhibits KRAS mutant and wildtype colon cancer and modulates human creatine levels

Colorectal cancer (CRC) is a leading cause of cancer mortality. Creatine metabolism was previously shown to critically regulate colon cancer progression. We report that RGX-202, an oral small-molecule SLC6A8 creatine transporter inhibitor, robustly inhibits creatine import in vitro and in vivo, reduces intracellular phosphocreatine and ATP levels and induces tumor cell apoptosis in CRC. RGX-202 suppressed tumor growth across KRAS wild-type and KRAS mutant xenograft, syngeneic and patient-derived xenograft colorectal cancers. Anti-tumor efficacy correlated with tumoral expression of creatine kinase B. Combining RGX-202 with 5- fluorouracil or the DHODH inhibitor leflunomide caused regressions of multiple colorectal xenograft and PDX tumors of distinct mutational backgrounds. RGX-202 also perturbed creatine metabolism in metastatic CRC patients enrolled in a Phase-1 trial, mirroring pharmacodynamic effects on creatine metabolism observed in mice. This is, to our knowledge, the first demonstration of pre-clinical and human pharmacodynamic activity for creatine metabolism targeting in oncology, revealing a critical target for CRC.

cancer biology↗

bioRxiv2021

Two Isoleucyl tRNAs that Decode 'Synonymous' Codons Divergently Regulate Breast Cancer Progression

The human genome contains 61 codons that encode for the 20 amino acids. The synonymous codons of a given amino acid are decoded by a set of transfer RNAs (tRNAs) called isoacceptors. We report the surprising observation that two isoacceptor tRNAs that decode synonymous codons are modulated in opposing directions during breast cancer progression. Specifically, tRNAIleUAU is upregulated, whereas tRNAIleGAU is repressed as breast cancer cells attained enhanced metastatic capacity. Functional studies revealed that tRNAIleUAU promoted and tRNAIleGAU suppressed metastatic colonization. The expression of these tRNAs mediated opposing effects on codon-dependent translation of growth promoting genes. Consistent with this, multiple mitotic gene sets in the human genome are significantly enriched in the codon cognate to the growth-promoting tRNAIleUAU and significantly depleted of the codon cognate to the growth-suppressive tRNAIleGAU. Our findings uncover a specific isoacceptor tRNA pair that act in opposition--divergently regulating genes that contribute to growth and a disease phenotype. The degeneracy of the genetic code can thus be biologically exploited by human cancer cells via tRNA isoacceptor shifts that facilitate the transition towards a growth-promoting state.

cancer biology↗

bioRxiv2019

PCK1 and DHODH drive colorectal cancer liver metastatic colonization and hypoxic pyrimidine nucleotide anabolic biosynthesis

Colorectal cancer (CRC) is a major cause of human death. Mortality is primarily due to metastatic organ colonization, with liver being the primary organ affected. We modeled metastatic CRC (mCRC) liver colonization using patient-derived primary and metastatic tumor xenografts (PDX). Such PDX modeling predicted patient survival outcomes. In vivo selection of multiple PDXs for enhanced metastatic capacity upregulated the gluconeogenic enzyme PCK1, which enhanced metastatic hypoxic survival by driving anabolic pyrimidine nucleotide biosynthesis. Consistently, highly metastatic tumors upregulated multiple pyrimidine biosynthesis intermediary metabolites. Therapeutic inhibition of the pyrimidine biosynthetic enzyme DHODH with oral leflunomide substantially impaired CRC liver metastatic colonization and hypoxic survival. Our findings provide a potential mechanistic basis for the epidemiologic association of anti-gluconeogenic drugs with improved CRC metastasis outcomes, reveal the exploitation of a gluconeogenesis enzyme for pyrimidine biosynthesis during hypoxia, and implicate DHODH and PCK1 as metabolic therapeutic targets in colorectal cancer metastasis.

cancer biology↗

bioRxiv2019

Germline genetic determination of cancer progression and survival

We report the surprising finding that common germline polymorphisms of APOE, present in approximately 39% of Caucasians, predict survival outcomes in human melanoma. Analysis of The Cancer Genome Atlas revealed that carriers of the APOE2 variant experienced shorter survival relative to APOE3 homozygotes, while APOE4 variant carriers exhibited increased survival. Consistent with this, melanoma growth in human APOE knock-in mice followed the order of APOE2 > APOE3 > APOE4, revealing causal regulation of progression by APOE variants. Mechanistically, recombinant ApoE protein variants differentially suppressed melanoma cell invasion and endothelial recruitment phenotypes. Moreover, tumors in APOE4 mice exhibited greater immune cell infiltration and activation relative to tumors of APOE2 mice. These findings support the notion that human germline genetic makeup can impact the trajectory of a future malignancy.

cancer biology↗

bioRxiv2018

An adaptive stress-induced tRNA depletion response mediates codon-based gene repression and growth suppression

Eukaryotic transfer RNAs can become selectively fragmented upon various stresses, generating tRNA-derived small RNA fragments. Such fragmentation has been reported to impact a small fraction of the tRNA pool and thus presumed to not directly impact translation. We report that oxidative stress can rapidly generate tyrosine tRNAGUA fragments in human cells--causing significant depletion of the precursor tRNA. Tyrosine tRNAGUA depletion impaired translation of growth and metabolic genes enriched in cognate tyrosine codons. Depletion of tyrosine tRNAGUA or its translationally regulated targets USP3 and SCD repressed proliferation--revealing a dedicated tRNA-regulated growth suppressive pathway for oxidative stress response. Tyrosine fragments are generated in a DIS3L2 exoribonuclease-dependent manner and inhibit hnRNPA1-mediated transcript destabilization. Moreover, tyrosine fragmentation is conserved in C. elegans. Thus, tRNA fragmentation can coordinately generate trans-acting small-RNAs and functionally deplete a tRNA. Our findings reveal the existence of an underlying adaptive codon-based regulatory response inherent to the genetic code.

molecular biology↗