Biology subjects

Gasparre, G.

Publications and source records attributed to Gasparre, G..

5 recordsLinked to original sources

bioRxiv2026

Abolishing respiratory complex I decreases in vivo growth of high grade serous ovarian cancer cells and sensitizes to anti-angiogenic therapy

Targeting mitochondrial Complex I (CI) is a currently emerging anti-cancer strategy, with several enzyme inhibitors entering clinical trials. Among others, aggressive high-grade serous tubo-ovarian cancer (HGSOC) may particularly benefit from this therapeutic approach due to the scarce response to first- and second-line treatments, with consequent high mortality, such as the anti-angiogenic bevacizumab. We here show that CI represents a vulnerability in HGSOC, which can be exploited for therapeutic intervention. Indeed, ablating CI function in OV-90 HGSOC cells led to significant in vivo tumor growth decrease, smaller masses, and lower KI-67 proliferative index. This was confirmed in a switch-off system in which CI deprivation was induced during tumor progression to mimic pharmacologic treatment, suggesting this result can be achieved in growing neoplasms. We also show that abolishing CI in HGSOC cells leads to failure in stabilizing the hypoxia inducible factor-1a and to respond to hypoxia through the transcriptional activation of its target genes, ultimately lowering vascular endothelial growth factor (VEGF) and generating an immature intratumor vascular system accompanied by a decreased blood flow. Last, we demonstrate that targeting CI sets the biological basis for increased sensitivity to anti-angiogenics, as CI-deprived tumors displayed growth arrest when bevacizumab was administered, unlike their CI-competent counterpart. Our findings point to CI inhibition as a booster for anti-VEGF therapies and pave the way for combined protocols in treatment of HGSOC.

cancer biology↗

bioRxiv2025

Combining circulating tumor cell and circulating cell free DNA analyses enhances liquid biopsy sensitivity in detecting high grade serous tubo-ovarian carcinoma

BackgroundLiquid biopsy is a promising strategy for detecting and monitoring neoplastic diseases, with circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) being the most common objects of investigation. Most analyses have focused on these biomarkers separately, and simultaneous detection has not yet been attempted in high grade serous tubo-ovarian carcinoma (HGSOC). The aim of our study was to assess whether the tandem CTC/ctDNA approach increases HGSOC detection efficiency of peripheral blood liquid biopsy. MethodsFor CTC detection, by using healthy donor samples spiked with known cancer cell numbers, we tested gene expression assays and TP53 next-generation sequencing (NGS). The latter was also applied for ctDNA detection where analytical validity was ensured by calculating the optimal variant allele frequency (VAF) threshold for mutation calling. The clinical validity of the assays was then verified on two HGSOC cohorts and respective controls. Standard 2x2 contingency tables and Wilson method were used to evaluate clinical validity, by calculating specificity, sensitivity, and accuracy with 95% confidence intervals (CI). ResultsHigh analytical sensitivity and specificity were found for both gene expression and TP53 NGS based CTC detection, as these assays specifically detected as few as five cancer cells spiked in control sample. Regarding clinical validity, the gene expression-based CTC detection showed 0.48 accuracy, 13.3% sensitivity, and 100% specificity, whereas TP53 sequencing demonstrated better assay performance (0.77 accuracy, 46.7% sensitivity, 100% specificity). For circulating cell-free DNA (cfDNA) analysis, we first identified 0.31% VAF cut-off for accurate ctDNA TP53 mutation calling. Subsequent clinical validity assessment showed solid performance efficiency of the ctDNA based liquid biopsy (0.71 accuracy, 60% sensitivity, and 100% specificity), outperforming the CTC detection methods. Importantly, the tandem ctDNA/CTC analysis improved disease detection rate in both HGSOC cohorts, allowing to achieve, respectively, 73.3% and 93.3% sensitivity. Interestingly, TP53 NGS revealed CTC private variants, and shared ctDNA/CTC mutations undetected in the primary tissue, highlighting the ability of the dual-analyte approach to capture tumor heterogeneity and allow mutation cross-validation. ConclusionsOur study reveals the complementary value of simultaneous CTC and cfDNA analysis in HGSOC, advancing the translational potential of liquid biopsy integration for the management of this disease.

cancer biology↗

bioRxiv2025

miR-6850 Drives Phenotypic Changes and Signaling in High Grade Serous Ovarian Cancer

MicroRNAs (miRNAs) are key post-transcriptional regulators of gene expression, and their dysregulation is closely linked to cancer development. Ovarian cancer (OC), particularly the high-grade serous ovarian carcinoma (HGSOC) subtype, is the most lethal gynecological malignancy, primarily due to late-stage diagnosis and limited treatment options. Among the miRNAs encoded at the often amplified 8q24.3 region, miR-6850 has emerged as a potential candidate target owing to its genomic positioning inside this hotspot and its unexpectedly low expression in HGSOC tissues and cell lines. In silico investigations indicated that, despite the gain in MIR6850 copy number, its mature products, miR-6850-5p and miR-6850-3p, were expressed at low levels; notably, MIR6850 gene amplification was associated with enhanced disease-specific survival. Functional studies revealed that ectopic production of both isoforms in SKOV-3 and NIH:OVCAR3 cells inhibited proliferation, compromised clonogenic capacity, and disturbed cell cycle progression. Moreover, miR-6850 altered cell phenotype by facilitating mesenchymal-to-epithelial transition (MET), as shown by the overexpression of E-cadherin and {beta}-catenin and the downregulation of Slug and Vimentin. It also regulated cell adhesion and migration while reducing global protein synthesis via the downregulation of the PI3K/Akt/mTOR pathway. Our results together identify miR-6850 as a tumor-suppressive miRNA in HGSOC, demonstrating its diverse anti-oncogenic actions and underscoring its potential as a prognostic biomarker and therapeutic target in ovarian cancer.

cancer biology↗

bioRxiv2020

Biogenesis of NDUFS3-less complex I indicates TMEM126A/OPA7 as an assembly factor of the ND4-module

Complex I (CI) is the largest enzyme of the mitochondrial respiratory chain and its defects are the main cause of mitochondrial disease. To understand the mechanisms regulating the extremely intricate biogenesis of this fundamental bioenergetic machine, we analyzed the structural and functional consequences of the ablation of NDUFS3, a non-catalytic core subunit. We prove that in diverse mammalian cell types a small amount of functional CI can still be detected in the complete absence of NDUFS3. In addition, we have determined the dynamics of CI disassembly when the amount of NDUFS3 is gradually decreased. The process of degradation of the complex occurs in a hierarchical and modular fashion where the ND4-module remains stable and bound to TMEM126A. We have thus, uncovered the function of TMEM126A, the product of a disease gene causing recessive optic atrophy, as a factor necessary for the correct assembly and function of CI.

biochemistry↗

bioRxiv2018

Mice harboring a SCA28 patient mutation in AFG3L2 develop late-onset ataxia associated with enhanced mitochondrial proteotoxicity.

Spinocerebellar ataxia 28 is an autosomal dominant neurodegenerative disorder caused by missense mutations affecting the proteolytic domain of AFG3L2, a major component of the mitochondrial m-AAA protease. However, little is known of the underlying pathogenetic mechanisms or how to treat patients with SCA28. Currently available Afg3l2 mutant mice harbour deletions that lead to severe, early-onset neurological phenotypes that do not faithfully reproduce the late-onset and slowly progressing SCA28 phenotype. Here we describe production and detailed analysis of a new knock-in murine model harbouring an Afg3l2 allele carrying the p.Met665Arg patient-derived mutation. Heterozygous mutant mice developed normally but signs of ataxia were detectable by beam test at 18 months. Cerebellar pathology was negative; electrophysiological analysis showed increased spontaneous firing in Purkinje cells from heterozygous mutants with respect to wild-type controls, although not statistically significant. As homozygous mutants died perinatally with evidence of cardiac atrophy, for each genotype we generated mouse embryonic fibroblasts (MEFs) to investigate mitochondrial function. MEFs from mutant mice showed altered mitochondrial bioenergetics, with decreased basal oxygen consumption rate, ATP synthesis and mitochondrial membrane potential. Mitochondrial network formation and morphology was also altered, in line with greatly reduced expression of Opa1 fusogenic protein L-isoforms. The mitochondrial alterations observed in MEFs were also detected in cerebella of 18-month-old heterozygous mutants, suggesting they may be a hallmark of disease. Pharmacological inhibition of de novo mitochondrial protein translation with chloramphenicol caused reversal of mitochondrial morphology in homozygous mutant MEFs, supporting the relevance of mitochondrial proteotoxicity for SCA28 pathogenesis and therapy development.

genetics↗