Biology subjects

Lujambio, A.

Publications and source records attributed to Lujambio, A..

11 recordsLinked to original sources

bioRxiv2026

B cells sustain tumor-specific CD4 T cells to promote response to PD-1 targeted therapy

Immunotherapy transformed cancer treatment, yet precise correlates of response remain to be defined. While intratumoral follicular helper like (Tfhl) CD4 T cells and IgG1+ B cells have been associated with improved outcomes to PD-1 blockade for hepatocellular carcinoma (HCC), their mechanisms contributing to response are unclear. To address this question, we developed a murine model of HCC and examined CD8, CD4 and B cell responses. Increasing CD4-help sensitizes mice to PD-1 blockade, in a CD4- and CD8-dependent manner. Tumor-specific CD4 T cells contained Tfhl and Th1 populations, and both Bcl6 and T-bet were required for efficacy. Antigen-specific B cells were essential for CD4-helper expansion, yet secretion of antibodies was not required for long-term survival. Thus, B cells are critical for effective immunotherapy, but secreted antibodies are not.

immunology↗

bioRxiv2025

Bacteroidetes promote hepatocellular carcinoma progression and resistance to immunotherapy

Background and AimsGrowing evidence highlight the critical role of the gut microbiome in tumorigenesis and response to immunotherapies. However, the impact of gut microbes on hepatocellular carcinoma (HCC) progression and response to immune-checkpoint blockade (ICB) remains unclear due to the lack of combined preclinical and clinical studies. Approach & ResultsWe performed 16S rRNA of cross-cohort stool samples from 10 HCC responders (R) and 40 non-responders (NR) to ICB at baseline and on-treatment time-points. We identified an enrichment of Bacteroidetes in NR. To study the role of the microbiome in the cancer immune response, we generated an immunogenic mouse model of HCC via hydrodynamic tail-vein injection (HDTVI) of DNA plasmids mimicking common HCC alterations and immunogenicity by expressing model antigens (MYC-lucOS;CTNNB1 tumors). We found that antibiotic (ABX)-induced dysbiosis promoted a pro-tumorigenic effect in the MYC-lucOS;CTNNB1 HCC model by the expansion of a specific Bacteroidetes, Parabacteroides distasonis. Colonization of mice carrying MYC-lucOS;CTNNB1 HCCs with Parabacteroides distasonis confirmed its pro-tumorigenic effect in vivo. Furthermore, we explored the effects of colonizing with microbiotas from patients and showed that microbiota from a NR donor enriched in Bacteroidetes promoted faster tumorigenesis than microbiota from a R donor with reduced Bacteroidetes. We isolated 6 Bacteroidetes species from the NR donor, cultured them, and used them as a cocktail to colonize mice; similarly, mice transplanted with this cocktail showed increased tumorigenesis and reduced survival. ConclusionsThis study identified Bacteroidetes enrichment as a potential biomarker of ICB resistance in HCC and, by using immunogenic mouse models, established that Bacteroidetes abundance influences tumor development.

cancer biology↗

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↗

bioRxiv2025

Demonstration of SLU7 as a new pan-cancer target

Cancer treatment remains challenging due to heterogeneous responses to immunotherapy across patients and tumor types. Innovative strategies are required to overcome immune evasion. We have identified the splicing factor SLU7 as essential for the survival of cancer cells from diverse origins. SLU7 knockdown induces R-loop accumulation, transcription-dependent genomic instability, DNA damage, and replication catastrophe, together with aberrant splicing and inhibition of nonsense-mediated mRNA decay (NMD) and/or DNA methylation. These alterations lead to the expression of neoantigens, interferon B1, endogenous retroviruses, and cancer-testis antigens, which would enhance tumor immunogenicity. Therefore, we propose SLU7 targeting as a dual-action therapy, combining direct tumor suppression with immune activation. Using various murine cancer models, including orthotopic liver tumors, and multiple molecular strategies--such as inducible CRISPR/Cas9, systemic delivery of chimeric siSLU7-nucleolin aptamers (APTASLU), and intratumoral injection of siSLU7-loaded nanoparticles--we show that distinct siSLU7 sequences and delivery platforms effectively inhibit tumor growth. Furthermore, SLU7 silencing synergizes with immune checkpoint inhibitors, amplifying anti-tumor responses. Our in vivo data demonstrate that SLU7 is a promising, versatile target for diverse cancers. Its multimodal mechanism offers potential to overcome tumor heterogeneity, reverse immune tolerance, and enhance immunotherapy efficacy.

cancer biology↗

bioRxiv2025

Targeting ZNRF3 and RNF43 to Restore Regeneration and Reverse Metabolic Dysfunction-Associated Steatotic Liver Disease

Liver regeneration and hepatocyte metabolic identity are disrupted in metabolic dysfunction-associated steatotic liver disease (MASLD) and its advanced form, metabolic dysfunction-associated steatohepatitis (MASH), yet the mechanisms of restore liver regeneration and reprogram metabolism for disease reversal remains poorly understood. Here, we show that {beta}-Catenin activity progressively declines in hepatocytes during MASH in both humans and mice, coinciding with impaired regeneration and defective lipid clearance. Targeted deletion of the endogenous WNT pathway inhibitors ZNRF3 and RNF43 in hepatocytes after MASH onset reactivates {beta}-Catenin signaling, leading to robust regression of steatosis, inflammation, and fibrosis, and restoring regenerative capacity across multiple fatty liver disease models. Mechanistically, this therapeutic effect is driven by {beta}-Catenin-dependent induction of the alternative bile acid synthesis pathway without disrupting systemic lipid homeostasis. Importantly, both short-and long-term deletion of ZNRF3/RNF43 restores liver function without triggering tumorigenesis or hepatotoxicity, indicating a safe therapeutic window. These findings reveal that physiological activation of WNT/{beta}-catenin signaling via ZNRF3 and RNF43 offers a viable regenerative and metabolic strategy for reversing fatty liver disease.

cell biology↗

bioRxiv2024

Dendritic cells type 1 control the formation, maintenance, and function of tertiary lymphoidstructures in cancer

Tertiary lymphoid structures (TLS) are organized immune cell aggregates that arise in chronic inflammatory conditions. In cancer, TLS are associated with better prognosis and enhanced response to immunotherapy, making these structures attractive therapeutic targets. However, the mechanisms regulating TLS formation and maintenance in cancer are incompletely understood. Using spatial transcriptomics and multiplex imaging across various human tumors, we found an enrichment of mature dendritic cells (DC) expressing high levels of CCR7 in TLS, prompting us to investigate the role of DC in the formation and maintenance of TLS in solid tumors. To address this, we developed a novel murine model of non-small cell lung cancer (NSCLC) that forms mature TLS, containing B cell follicles with germinal centers and T cell zones with T follicular helper cells (TFH) and TCF1+PD-1+ progenitor exhausted CD8+ T cells (Tpex). Here we show that, during the early stages of tumor development, TLS formation relies on IFN{gamma}-driven maturation of the conventional DC type 1 (cDC1) subset, their migration to tumor-draining lymph nodes (tdLN), and recruitment of activated T cells to the tumor site. As tumors progress, TLS maintenance becomes independent of T cell egress from tdLN, coinciding with a significant reduction of cDC1 migration to tdLN. Instead, mature cDC1 accumulate within intratumoral CCR7 ligand-enriched stromal hubs. Notably, timed depletion of cDC1 or disruption of their migration to these stromal hubs after TLS are formed alters TLS maintenance. Importantly, we found that cDC1-mediated antigen presentation to both CD4+ and CD8+ T cells and intact CD40 signaling, is critical for the maintenance of TLS, the preservation of the TFH cell pool, the formation of germinal center and the production of tumor-specific IgG antibodies. These findings underscore the key role of mature cDC1 in establishing and maintaining functional TLS within tumor lesions and highlight the potential for cDC1-targeting therapies as a promising strategy to enhance TLS function and improve anti-tumor immunity in patients with cancer.

immunology↗

bioRxiv2024

NOTCH1 drives tumor plasticity and metastasis in hepatocellular carcinoma

Background & AimsLiver cancer, the third leading cause of cancer-related mortality worldwide, has two main subtypes: hepatocellular carcinoma (HCC), accounting the majority of the cases, and cholangiocarcinoma (CAA). Notch pathway primarily regulates the intrahepatic development of bile ducts, which are lined with cholangiocytes, but it can also be upregulated in 1/3 of HCCs. To better understand the role of NOTCH1 in HCC, we developed a novel mouse model driven by activated Notch1 intracellular domain (NICD1) and MYC overexpression in hepatocytes. MethodsUsing the hydrodynamic tail-vein injection method for establishing primary liver tumors, we generated a novel murine model of liver cancer harboring MYC overexpression and NOTCH1 activation. We characterized this model histopathologically as well as transcriptomically, utilizing both bulk and single cell RNA-sequencing. We also performed functional experiments using monoclonal antibodies. ResultsMYC;NICD1 tumors displayed a combined HCC-CCA phenotype with temporal plasticity. At early time-points, histology was predominantly "cholangiocellular", which then progressed to mainly "hepatocellular". The "hepatocellular" component was enriched in mesenchymal genes and gave rise to lung metastasis. Metastatic cells were enriched in the TGFB and VEGF pathways and their inhibition significantly reduced the metastatic burden. ConclusionsOur novel mouse model uncovered NOTCH1 as a driver of temporal plasticity and metastasis in HCC, the latter of which is, in part, mediated by angiogenesis and TGF{beta} pathways. Impact and ImplicationsThis study develops a novel murine model of NOTCH1-driven liver cancer, an understudied oncogene in HCC. Using this model, we show that NOTCH1 drives plasticity in HCC and metastasis to the lungs that can be therapeutically targeted through inhibition of VEGF and TGF{beta} pathways. HighlightsO_LINOTCH1 activation in combination with MYC overexpression drives combined HCC-CCA. C_LIO_LINOTCH1 activation in hepatocytes drives temporal plasticity. C_LIO_LINOTCH1 activation drives metastasis of HCC cells to the lungs, but not of CCA cells. C_LIO_LIAngiogenesis and TGF{beta} pathways mediate NOTCH1-induced lung metastasis. C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=93 SRC="FIGDIR/small/619856v2_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@143c866org.highwire.dtl.DTLVardef@119ddb6org.highwire.dtl.DTLVardef@12ad951org.highwire.dtl.DTLVardef@2160b8_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2024

ICOS limits memory-like properties and function of exhausted PD-1+ CD8 T cells

During persistent antigen stimulation, PD-1+CD8 T cells are maintained by progenitor exhausted PD-1+TCF-1+CD8 T cells (Tpex). Tpex respond to PD-1 blockade, and regulation of Tpex differentiation into more functional Tex is of major interest for cancer immunotherapies. Tpex express high levels of Inducible Costimulator (ICOS), but the role of ICOS for PD-1+CD8 T cell responses has not been addressed. In chronic infection, ICOS-deficiency increased both number and quality of virus-specific CD8 T cells, with accumulation of effector-like Tex due to enhanced survival. Mechanistically, loss of ICOS signaling potentiated FoxO1 activity and memory-like features of Tpex. In mice with established chronic infection, ICOS-Ligand blockade resulted in expansion of effector-like Tex and reduction in viral load. In a mouse model of hepatocellular carcinoma, ICOS inhibition improved cytokine production by tumor-specific PD-1+CD8 T cells and delayed tumor growth. Overall, we show that ICOS limits CD8 T cell responses during chronic antigen exposure.

immunology↗

bioRxiv2024

Integrated in vivo functional screens and multi-omics analyses identify alpha-2,3-sialylation as essential for melanoma maintenance

Glycosylation is a hallmark of cancer biology, and altered glycosylation influences multiple facets of melanoma growth and progression. To identify glycosyltransferases, glycans, and glycoproteins essential for melanoma maintenance, we conducted an in vivo growth screen with a pooled shRNA library of glycosyltransferases, lectin microarray profiling of benign nevi and melanoma patient samples, and mass spectrometry-based glycoproteomics. We found that -2,3 sialyltransferases ST3GAL1 and ST3GAL2 and corresponding -2,3-linked sialosides are upregulated in melanoma compared to nevi and are essential for melanoma growth in vivo and in vitro. Glycoproteomics revealed that glycoprotein targets of ST3GAL1 and ST3GAL2 are enriched in transmembrane proteins involved in growth signaling, including the amino acid transporter Solute Carrier Family 3 Member 2 (SLC3A2/CD98hc). CD98hc suppression mimicked the effect of ST3GAL1 and ST3GAL2 silencing, inhibiting melanoma cell proliferation. We found that both CD98hc protein stability and its pro-survival effect in melanoma are dependent upon -2,3 sialylation mediated by ST3GAL1 and ST3GAL2. In summary, our studies reveal that -2,3-sialosides functionally contribute to melanoma maintenance, supporting ST3GAL1 and ST3GAL2 as novel therapeutic targets in these tumors.

cancer biology↗

bioRxiv2022

The novel compensatory reciprocal interplay between neutrophils and monocytes drives cancer progression

Myeloid cells comprise the majority of immune cells in tumors, contributing to tumor growth and therapeutic resistance. Incomplete understanding of myeloid cells response to tumor driver mutation and therapeutic intervention impedes effective therapeutic design. Here, by leveraging CRISPR/Cas9-based genomic editing, we generated a mouse model that is deficient of all monocyte chemoattractant proteins (MCP). Using this strain, we effectively abolished monocyte infiltration in glioblastoma (GBM) and hepatocellular carcinoma (HCC) murine models, which were enriched for monocytes or neutrophils, respectively. Remarkably, eliminating monocyte chemoattraction invokes a significant compensatory neutrophil influx in GBM, but not in HCC. Single-cell RNA sequencing revealed that intratumoral neutrophils promoted proneural-to-mesenchymal transition in GBM, and supported tumor aggression by facilitating hypoxia response via TNF production. Importantly, genetic or pharmacological inhibiting neutrophil in HCC or qMCP-KO GBM extended the survival of tumor-bearing mice. Our findings emphasize the importance of targeting both monocytes and neutrophils simultaneously for cancer immunotherapy. In BriefEliminating monocyte chemoattraction invokes compensatory neutrophil influx in tumor, and vice versa, rendering current myeloid-targeted therapies ineffective. Using genetic and pharmacological approaches combined with novel mouse models of GBM and HCC, we provide credence advocating for combinational therapies aiming at inhibiting both monocytes and neutrophils simultaneously. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=153 SRC="FIGDIR/small/500690v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@bbbae5org.highwire.dtl.DTLVardef@eb3eecorg.highwire.dtl.DTLVardef@702696org.highwire.dtl.DTLVardef@f54734_HPS_FORMAT_FIGEXP M_FIG C_FIG Highlights* Blocking monocyte chemoattraction results in increased neutrophil infiltration. * Increased neutrophil recruitment induces GBM PN to MES transition. * Inhibiting neutrophil infiltration in monocyte-deficient tumors improves mouse GBM survival. * Blocking neutrophil, but not monocyte, infiltration in HCC prolongs mouse survival.

immunology↗

bioRxiv2021

An epigenetic switch regulates the ontogeny of AXL positive/EGFR-TKI resistant cells by modulating miR-335 expression

Lung cancer remains the leading cause of cancer-related mortality worldwide, despite current advancements in research and therapeutics. Many patients diagnosed with lung cancer will develop resistance to chemotherapeutic agents. In the context of non-small cell lung cancers (NSCLC) harboring EGFR oncogenic mutations, augmented levels of AXL and GAS6 have been found to drive Erlotinib resistance in certain tumors with mesenchymal-like features. By studying the ontogeny of AXL-positive cells, we have identified a novel non-genetic mechanism of drug resistance based on cell-state transition. We demonstrate that AXL-positive cells are already present as a sub-population of cancer cells in Erlotinib-naive tumors and tumor-derived cell lines, and that the expression of AXL is regulated through a stochastic mechanism centered on the epigenetic regulation of miR-335. The existence of a cell-intrinsic program through which AXL-positive/Erlotinib-resistant cells emerge infers the need of treating tumors harboring EGFR-oncogenic mutations upfront with combinatorial treatments targeting both AXL-negative and AXL-positive cancer cells.

cancer biology↗