Biology subjects

Saigi, M.

Publications and source records attributed to Saigi, M..

3 recordsLinked to original sources

bioRxiv2026

Identification of Malignant Peripheral Nerve Sheath Tumor subtypes with distinct genomic identities

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft-tissue sarcomas arising sporadically or in people with neurofibromatosis type 1 (NF1). Their marked heterogeneity challenges diagnosis and has hampered an integrative view of MPNST molecular pathogenesis. Here, a thorough whole-genome and transcriptome analysis of MPNSTs and the re-analysis of a large independent cohort allowed us to identify three molecular subtypes of MPNSTs (G1-G3) with distinct genomic identities and clinicopathological features. Furthermore, it provided a simple and unifying model of MPNST development, defining a distinct progression path for each group. This work uncovers new genomic aspects of MPNSTs, including the identification of recurrent copy-neutral loss of heterozygosity regions, distinct copy-number profiles among G1-G3, and CDKN2A-inactivating translocations in pre-malignant lesions (ANNUBPs). Altogether, these analyses overcome the dominant influence of PRC2 status in MPNST classification and provide a framework for their differential diagnosis and potential precision oncology treatment. SIGNIFICANCEMPNST is a highly heterogeneous soft-tissue sarcoma with difficult clinical management and no effective systemic therapies. This work defines three molecular subtypes of MPNSTs with distinct development paths and histological and clinical characteristics with potential impact on translational studies and subtype-tailored treatments.

cancer biology↗

bioRxiv2021

Efficacy of CDK4/6 inhibitors in preclinical models of malignant pleural mesothelioma

There is no effective therapy for patients with malignant pleural mesothelioma (MPM) who progressed to platinum-based chemotherapy and immunotherapy. Here, we investigate the antitumor activity of CDK4/6 inhibitors using in vitro and in vivo preclinical models of MPM. Based on publicly available transcriptomic data of MPM, patients with CDK4 or CDK6 overexpression had shorter overall survival. Treatment with abemaciclib or palbociclib at 100 nM significantly decreased cell proliferation in all cell models. Both CDK4/6 inhibitors significantly induced G1 cell cycle arrest thereby increasing cell senescence and increased the expression of interferon signaling pathway and tumor antigen presentation process in culture models of MPM. In vivo preclinical studies showed that palbociclib significantly reduced tumor growth and prolonged overall survival in a platinum-naive and platinum resistant MPM mouse model. Treatment of MPM with CDK4/6 inhibitors decreased cell proliferation, mainly by promoting cell cycle arrest at G1 and by induction of cell senescence. Our preclinical studies provide evidence for evaluating CDK4/6 inhibitors in the clinic for the treatment of MPM.

cancer biology↗

bioRxiv2020

SMARCA4 deficient tumours are vulnerable to KDM6A/UTX and KDM6B/JMJD3 blockade

Despite the genetic inactivation of SMARCA4, a core component of the SWI/SNF-complex commonly found in cancer, there are no therapies that effectively target SMARCA4-deficient tumours. Here, we show that, unlike the cells with activated MYC oncogene, cells with SMARCA4 inactivation are refractory to the histone deacetylase inhibitor, SAHA, leading to the aberrant accumulation of H3K27me3. This is associated with impaired transactivation and significantly reduced levels of the histone demethylases KDM6A/UTX and KDM6B/JMJD3, which confer a strong dependency on the KDM6s in the SMARCA4-mutant cells, so that its inhibition compromises cell viability. Administering the KDM6 inhibitor GSK-J4 to mice orthotopically implanted with SMARCA4-mutant lung cancer cells or primary small cell carcinoma of the hypercalcaemic type (SCCOHT) had strong anti-tumour effects. Our results highlight the vulnerability of KDM6 inhibitors as a characteristic that could be exploited for treating SMARCA4-mutant cancer patients.

cancer biology↗