Biology subjects

Lacunza, E.

Publications and source records attributed to Lacunza, E..

8 recordsLinked to original sources

bioRxiv2026

Kaposi Sarcoma Herpes Virus Reprograms Mesenchymal Cell Glycosylation to control platelet-derived growth factor receptor A signaling

Kaposi sarcoma-associated herpesvirus (KSHV) reprograms host cellular pathways to promote viral persistence and tumor development by supporting the survival and expansion of infected and bystander cells. Among the signaling axes implicated in this process, oncogenic activation of receptor tyrosine kinases, particularly platelet-derived growth factor receptor alpha (PDGFRA), is a well-established hallmark of Kaposi sarcoma pathogenesis. However, the impact of virus-driven cell surface glycosylation changes in PDGFRA-associated signaling remains uncertain. Here, we identified a critical role for KSHV in reshaping the glycosylation landscape of mesenchymal stromal cells (MSCs), thereby reprogramming PDGFRA signaling. We show that KSHV infection enhances a unique glycan profile in human and mouse MSCs, enriched in branched complex N-glycans with limited (2-6) sialylation, Transcriptomic analyses of KSHV-infected MSCs and Kaposis Sarcoma patient samples revealed a coordinated dysregulation of pathways involved in carbohydrate metabolism, nucleotide-sugar transport, and sialic acid turnover, with a particular focus on sialic acid turnover (NPL/NEU3), the UDP-N-acetylglucosamine transporters SLC35A3/B4, and complex N-glycan elongation (MGAT5/B3GNT2/B4GALT1) as critical nodes underlying reduced (2-6) sialylation and increased N-glycan branching. This remodeled glycan landscape contributes to create a permissive context for galectin-1 (Gal-1) binding, which in turn enhances PDGFRA activation and downstream signaling. These findings identify an integral component of KSHV-driven mesenchymal cell reprogramming, unveiling a lectin-dependent mechanism of RTK activation in Kaposi sarcoma pathogenesis.

Cancer Biology↗

bioRxiv2026

Hypoxia drives trastuzumab resistance through Rac1 pathway in HER2-positive breast cancer

Resistance to targeted therapy in HER2-positive breast cancer remains a clinical challenge, especially for patients with relapsed or metastatic disease. Particularly, persistent activation of hypoxia-inducible factor 1 (HIF-1) signalling is well documented in the context of trastuzumab and trastuzumab emtansine resistance. To achieve a deeper understanding of how HIF-1 activity modulates the response to anti-HER2 treatment, we functionally characterized a cellular model of hypoxia-induced drug resistance for HER2-positive breast cancer using shotgun proteomics. By global phosphoproteomics profiling, the Rac1 pathway was identified as one of the most enriched signalling networks under hypoxia. Furthermore, the selective Rac1 blockade with the 1A-116 small-molecule inhibitor sensitised HER2-positive cells to trastuzumab in both 2D and 3D culture systems. Altogether, our findings demonstrate that hypoxic conditions induce the resistance of HER2-positive breast cancer cells to targeted therapy and suggest the therapeutic potential of Rac1 inhibition to enhance trastuzumab efficacy. HighlightsO_LIHypoxic conditions induce trastuzumab resistance in HER2-positive breast cancer. C_LIO_LIRac1 signalling was mapped under hypoxia by phosphoproteomics profiling. C_LIO_LIRac1 inhibition sensitises HER2-positive cells to trastuzumab. C_LI

cancer biology↗

bioRxiv2025

HIV Infection and Opioid Treatment Enable the Engraftment of Kaposi Sarcoma-like Tumors into Immunocompetent Mice

The Kaposi Sarcoma herpesvirus (KSHV) causes Kaposi sarcoma (KS), primary effusion lymphoma, a lymphoproliferative disease (KSHV-multicentric Castlemans disease), and a cytokine inflammatory syndrome (KICS). These diseases occur more frequently, though not exclusively, among people living with HIV or other types of immune dysregulation. While limited KS can regress with immune reconstitution, such as through antiretroviral therapy (ART) in people living with HIV, there are currently no curative treatments for advanced KS. Preventive or therapeutic vaccines targeting KSHV could have a significant clinical impact; however, the development and testing of such strategies have been limited by the lack of preclinical models that faithfully recapitulate KS, including the presence of infected spindle cells and a relevant immune microenvironment. HIV/AIDS is an important cofactor for KS, and globally, the majority of individuals with KS are HIV-infected. Current evidence indicates that HIV-1 may enable KS progression through immunosuppression and promote pathogenesis by inducing inflammatory cytokines and producing secreted regulatory proteins like Tat and Nef. The design and testing of new therapeutic approaches based on pathogenesis are hampered by the lack of models that replicate KSHV oncogenesis in the context of HIV/AIDS. In the present study, we demonstrate that KSHV-infected cells can form tumors in an immunocompetent mouse model, but only when these mice are pretreated with EcoHIV and morphine, both of which have immunomodulatory and pro-inflammatory effects. These tumors exhibit gene expression profiles and immune microenvironments that closely resemble those observed in human KS lesions. This novel KSHV tumor model in immunocompetent mice provides a valuable platform to test immunotherapeutic strategies for KS, including immunomodulatory agents, targeted antibody therapies, checkpoint inhibitors, and vaccines. Author SummaryKaposi sarcoma (KS) is a cancer caused by the Kaposis sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8). A vaccine against this virus could prevent or cure this malignancy. However, there are no good animal models with an immune system to test new immunization approaches. The possibility of having KSHV-driven tumors develop in immunocompetent mice due to EcoHIV infection presents a unique opportunity to create an AIDS-KS mouse model suitable for testing immune-based therapies and KSHV vaccines in a scenario that replicates important aspects of AIDS-KS. These first-in-kind murine models incorporating a biologically relevant mouse HIV infection tool make our models unique and original, with the potential to provide novel mechanistic and pathobiological insights.

microbiology↗

bioRxiv2025

SPARC is a new driver of early breast tumor progression via TGF-β -dependent mechanism.

Ductal carcinoma in situ (DCIS) is a pre-invasive lesion that is thought to be a precursor of invasive ductal carcinoma (IDC). The challenge lies in discriminating between DCIS progressors and DCIS non-progressors, often resulting in over- or under-treatment in many cases. Membrane type 1 (MT1)-matrix metalloproteinase (MMP) has been previously identified as an essential gene involved in DCIS progression. Here, RNA-sequencing analysis of MT1-MMPhigh subpopulation derived from invasive breast tumors in the intraductal xenograft model was compared against a dataset of human high-grade DCIS, and Secreted Protein Acidic and Cysteine Rich (SPARC) has emerged as a master candidate involved in early breast tumor progression. We report that SPARC is up-regulated in DCIS as compared to normal breast epithelial tissues, and further increased in IDC relative to synchronous DCIS foci. We found a positive correlation between SPARC and MT1-MMP expression in DCIS lesions. At the mechanistic level, depletion of SPARC reduced MT1-MMP expression, the degradative capacity of the cells and the activation of the TGF-{beta} signalling canonical pathway. Pharmacological inhibition of the TGF-{beta} signalling pathway decreased SPARC and MT1-MMP at the mRNA and protein level, and concomitantly the cell degradative capacity and 3D cell migration. Strikingly, inhibition of the TGF-{beta} signalling pathway limits the invasive transition of breast tumors in a new triple-negative mouse intraductal syngeneic xenograft model. Moreover, high SPARC expression was positively correlated with both, TGF-{beta} and its receptor, TGFBRI, in a basal type of breast cancer collection supporting our findings. This study identifies SPARC as a new driver of early breast tumor progression via a TGF-{beta}-dependent mechanism, suggesting TGF-{beta} signaling pathway as a potential target for patients with high SPARC expression.

cancer biology↗

bioRxiv2023

COGNITIVE REJUVENATION IN OLD RATS BY HIPPOCAMPAL OSKM GENE THERAPY

Impaired performance in spatial learning and memory during aging in rats is associated with morphological and molecular changes in the brain, particularly in the hippocampus. Here, we assessed the cognitive performance of young (3.5 mo.) untreated rats and old (25.3 mo.) treated and control rats. Treatment was carried out by intrahippocampal injection of an adenovector that carries the GFP reporter gene as well as the 4 Yamanaka genes. Learning and spatial memory performance were assessed by means of the Barnes maze test. The learning performance of the OSKM-treated old rats was significantly improved compared to that of the control old counterparts. A marginal (P=0.06) improvement in the spatial memory was recorded in the treated versus control old rats. OSKM gene expression induced no pathological changes in the brain. The morphology and number of hippocampal cell populations like astrocytes and mature neurons did not show any changes with the treatment in the old rats as compared with the control old counterparts. The rat pan tissue DNAm age marker revealed that old OSKM gene-treated rats show a trend towards a decrease in epigenetic age. The Limma package was used to assess differential methylation by fitting linear models to the methylation data for specific group comparisons. Comparison of differential methylation between old treated and old control hippocampal DNA samples identified 671 differentially methylated CpGs probes (DPMs) in the DNA of OSKM-treated hippocampi (p<0.05). Assessment of the DPMs in old versus young controls revealed the presence of 1,279 hypomethylated CpGs near the promoter regions in young hippocampi (versus old controls) and 914 hypermethylated CpGs near the promoter in young hippocampi compared to old control hippocampi. We found a subset of 174 hypomethylated CpGs in the hippocampal DNA from old OSKM rats and young controls both compared with old control hippocampi. This means that in the hippocampal DNA there is a common set of CpGs which are hypermethylated during aging and are demethylated by the OSKM genes. This observation suggested that in these 174 CpGs the hypermethylation induced by aging is reversed by the demethylation effect of the OSKM genes on the same 174 CpGs. This observation can be interpreted as a rejuvenation effect of the OSKM genes of the old hippocampal methylome. Our results extend to the rat the evidence that viral vector-mediated delivery of the Yamanaka genes in the brain has strong regenerative effects without adverse side effects.

neuroscience↗

bioRxiv2023

Single-cell RNA sequencing identifies KSHV-infected Mesenchymal stem cell subpopulations precursors of Kaposi's Sarcoma

Kaposis sarcoma (KS) may derive from Kaposis Sarcoma Herpesvirus (KSHV)-infected human Mesenchymal Stem Cells (hMSCs) migrating into an inflammatory and angiogenic site, enhancing KS initiation. KSHV infection of primary hMSCs uncovers specific cell subpopulations, mechanisms, and conditions involved in the first steps of the KSHV-induced transformation and reprogramming process toward KS progenitor cells. The pro-angiogenic environmental conditions allowed KSHV to reprogram hMSCs closer to KS gene expression profiles and points to KSHV infection as an important factor inducing the Mesenchymal-to-Endothelial (MEndT) transition of hMSC. Single-cell RNA-sequencing analysis revealed a subpopulation of infected cells growing in a pro-angiogenic environment with both viral and host oncogenes upregulation. This highlights the importance of this condition in boosting the KSHV-induced transformation and reprogramming of hMSC towards MEndT and closer to KS gene expression profiles, reinforcing the notion of these cell subpopulations as KS precursors.

microbiology↗

bioRxiv2021

Counterbalance of Foxp3 and IDO expression at different tumor stages in aggressive breast cancer subtypes

Foxp3 and IDO1 are known immunomodulatory molecules involved in tumor escape and could be related to tumor infiltrating lymphocytes (TILs) in the tumor microenvironment. In this study, tumoral Foxp3 and IDO1 expression in breast cancer were evaluated in relation to lymphocyte biomarkers such as CD8 and CD45R0, regulatory T cells, as well as intratumoral and stromal TILs (iTILs and sTILs, respectively). Clinical and histopathological features were also included in the analysis. Foxp3 and IDO1 were found in tumor cells showing mainly cytoplasmic patterns in 60% and 62% tumor samples, respectively. TILs were found in 76% of samples; iTILs were detected in 92% of those samples and sTILs in 55%. Foxp3+ TILs were detected only in 12% of TILs+ samples associated with tumoral Foxp3 expression. Tumoral Foxp3 was mainly expressed at lower tumor stages while IDO1 expression was associated with advanced tumor stages; both correlated with CD8+ TILs which were observed in 77% of TILs+ samples. CD45R0+ were observed in 81% of TILs+ samples and correlated with higher tumor stages and poorly differentiated tumors. In ER negative tumors, an inverse correlation between Foxp3 and IDO1 tumoral expression was found in relation to tumor stage. TNBC subtype showed a positive correlation with the presence of iTILs. In silico analysis showed that Foxp3 and coexpressed genes in breast cancer were associated with immune response genes. Foxp3 was found predominantly in Basal and Her2-enriched subtypes in relation to Luminal A subtype, by RNA seq and RNA microarray database analysis. In conclusion, the expression of Foxp3 and IDO1 in tumors at different stages suggests a potential compensatory mechanism to evade the strong CTL response observed. This is relevant since the cumulative data indicates that Foxp3 as well as IDO1 could be potential targets of immunotherapy in patients with tumors at different stages and for the most aggressive breast cancer subtypes such as TNBC and Her2-enriched. HIGHLIGHTSO_LIFoxp3 and IDO1 were found overexpressed in the cytoplasm of tumor cells, observed in BC samples at early or advanced tumor stages, respectively, both associated with abundant cytotoxic CD8+ lymphocytes infiltrates. C_LIO_LITumor immunosuppression by Foxp3 and IDO1 tumoral expression could counteract the attempt of the hosts immune system to eradicate the tumor by CD8+ and CD45R0+ TILs cytotoxic activity. C_LIO_LIIt is well-known the tolerogenic role of Foxp3 in Treg and less understood the role of Foxp3 in tumors. However, there is increasing evidence that Foxp3+ tumor cells appear to promote an immunosuppressive microenvironment similar to Treg. Whether this is a consequence of the effect of other immunosuppressive factors secreted by the tumor cells which can be induced by Foxp3 expression, such as TGF{beta}, remains to be determined. C_LI

cancer biology↗

bioRxiv2021

A non-coding RNA network involved in KSHV tumorigenesis

Regulatory pathways involving non-coding RNAs (ncRNAs) such as microRNAs (miRNAs) and long non-coding RNAs (lncRNA) have gained great relevance due to their role in the control of gene expression modulation. Using RNA sequencing of KSHV Bac36 transfected mouse endothelial cells (mECK36) and tumors, we have analyzed the host and viral transcriptome to uncover the role lncRNA-miRNA-mRNA driven networks in KSHV tumorigenesis. The integration of the differentially expressed ncRNAs, with an exhaustive computational analysis of their experimentally supported targets, led us to dissect complex networks integrated by the cancer-related lncRNAs Malat, Neat1, H19, Meg3 and their associated miRNA-target pairs. These networks would modulate pathways related to KSHV pathogenesis, such as viral carcinogenesis, p53 signaling, RNA surveillance, and Cell cycle control. Finally, the ncRNA-mRNA analysis allowed us to develop signatures that can be used to an appropriate identification of druggable gene or networks defining relevant AIDS-KS therapeutic targets.

cancer biology↗