Biology subjects

Alani, R. M.

Publications and source records attributed to Alani, R. M..

6 recordsLinked to original sources

bioRxiv2024

The CoREST complex inhibitor, corin, leads to decreased tumor growth, increased cellular differentiation and extended lifespan in atypical teratoid rhabdoid tumor xenograft models

BackgroundAtypical teratoid rhabdoid tumor (ATRT) is the most common malignant brain tumor in infants, and more than 60% of children with ATRT die from their tumor. ATRT is associated with mutational inactivation/deletion of SMARCB1, a member of the SWI/SNF chromatin remodeling complex, suggesting that epigenetic events play a critical role in tumor development and progression. Moreover, disruption of SWI/SNF allows unopposed activity of epigenetic repressors, which contribute to tumorigenicity. We therefore explored the role of the CoREST repressor complex in ATRT. MethodsWe evaluated the effects of the bifunctional LSD1/HDAC1/2 small molecule CoREST inhibitor, corin, on ATRT tumor cell growth, apoptosis, differentiation, gene expression and chromatin accessibility. ResultsWe found that corin inhibited the growth of ATRT cells regardless of their epigenetic subgroup, and was associated with increased tumor cell apoptosis and differentiation. ATAC-seq showed increases in chromatin accessibility in corin-treated ATRT cells, with changes seen at genes associated with neuronal differentiation and synaptic function. RNA-seq confirmed increased expression of neuronal differentiation genes and decreased DNA replication/cell cycle-associated genes in ATRT cells treated with corin. Corin suppressed orthotopic ATRT tumor growth, leading to significant extension of lifespan. In addition, increased histone acetylation (H3K9ac, H3K27ac) and methylation (H3K4Me1) was seen in corin-treated ATRT orthotopic xenografts, consistent with on-target pharmacodynamics. ConclusionThe CoREST inhibitor, corin, suppresses tumor growth, induces differentiation, and promotes apoptosis in ATRT, leading to significantly increased survival of mice bearing ATRT orthotopic xenografts. Our results suggest a potential application of CoREST complex inhibitors in patients with ATRT. Key PointsO_LICoREST complex inhibition by corin leads to decreased cell growth and increased apoptosis in ATRT C_LIO_LICorin promotes chromatin accessibility and neuronal differentiation in ATRT C_LIO_LICorin inhibits tumor growth and extends lifespan in ATRT animal models C_LI Importance of the StudyLoss of function of SMARCB1 is a hallmark of ATRT which leads to dysfunction of the mammalian SWI/SNF complex and an inability to counteract epigenetic repressor complexes. The CoREST complex functions as a chromatin remodeling complex that represses neuronal differentiation genes during development. Inhibition of the CoREST complex by corin in ATRT leads to decreased tumor cell growth, induction of apoptosis and increased survival of mice bearing ATRT orthotopic xenografts. These changes are associated with increased chromatin accessibility and expression of genes associated with neuronal differentiation. Corin therefore reverses the primary block of differentiation that maintains a stem cell state in ATRT, which contributes to tumorigenesis. These studies significantly improve our understanding of how to therapeutically address the underlying epigenetic drivers of ATRT and support further development of corin for ATRT.

cancer biology↗

bioRxiv2024

CoREST Complex Inhibition Alters RNA Splicing to Promote Neoantigen Expression and Enhance Tumor Immunity

ABSTRACTEpigenetic complexes tightly regulate gene expression and colocalize with RNA splicing machinery; however, the consequences of these interactions are uncertain. Here, we identify unique interactions of the CoREST repressor complex with RNA splicing factors and their functional consequences in tumorigenesis. Using mass spectrometry, in vivo binding assays, and cryo-EM we find that CoREST complex-splicing factor interactions are direct and perturbed by the CoREST complex inhibitor, corin, leading to extensive changes in RNA splicing in melanoma and other malignancies. Using predictive machine learning models and MHC IP-MS, we identify thousands of corin-induced neopeptides derived from unannotated splice sites which generate immunogenic splice-neoantigens. Furthermore, corin reactivates the response to immune checkpoint blockade and promotes dramatic expansion of cytotoxic T cells in an immune cold melanoma model. CoREST complex inhibition thus represents a unique therapeutic opportunity in cancer which creates tumor-associated neoantigens that enhance the immunogenicity of current therapeutics. Statement of SignificanceWe identify a novel role of the CoREST transcriptional repressor complex in regulating pre-mRNA splicing and find that the small molecule inhibitor, corin, promotes alternative splicing events in cancer leading to neoantigen expression and T cell-mediated immunity. This represents a potential approach to promote immunoreactive neoantigen expression in immune-cold tumors.

cancer biology↗

bioRxiv2024

The CoREST complex is a therapeutic vulnerability in malignant peripheral nerve sheath tumors

Malignant peripheral nerve sheath tumor (MPNST) is a highly aggressive sarcoma that may be seen in patients with neurofibromatosis type 1 (NF1) or occur sporadically. While surgery is the primary treatment for localized MPNST with a 61.9% overall survival rate, metastatic disease is often fatal due to resistance to systemic therapies which underscores the urgent need for effective treatments. MPNSTs frequently harbor inactivating driver mutations in the PRC2 epigenetic repressor complex suggesting epigenetic therapies may represent a specific vulnerability in these tumors. Here, we investigate the role of the LSD1-HDAC1-CoREST (LHC) repressor complex in mediating MPNST tumor growth and progression. Our findings demonstrate that the LHC small molecule inhibitor, corin, induces apoptosis and significantly inhibits proliferation in MPNST cells. Transcriptomic analysis of corin-treated MPNST cells demonstrates specific increases in genes associated with axonogenesis and neuronal differentiation as well as altered extracellular matrix; additionally, corin treatment is shown to inhibit MPNST invasion in vitro. These results underscore the critical role of the LHC complex in facilitating MPNST growth and progression and suggest that targeting the LHC complex represents a promising therapeutic approach for this aggressive malignancy.

cancer biology↗

bioRxiv2024

p300 KAT regulates SOX10 stability and function in human melanoma

SOX10 is a lineage-specific transcription factor critical for melanoma tumor growth, while SOX10 loss-of-function drives the emergence of therapy-resistant, invasive melanoma phenotypes. A major challenge has been developing therapeutic strategies targeting SOX10s role in melanoma proliferation, while preventing a concomitant increase in tumor cell invasion. Here, we report that the lysine acetyltransferase (KAT) EP300 and SOX10 gene loci on Chromosome 22 are frequently co-amplified in melanomas, including UV-associated and acral tumors. We further show that p300 KAT activity mediates SOX10 protein stability and that the p300 inhibitor, A-485, downregulates SOX10 protein levels in melanoma cells via proteasome-mediated degradation. Additionally, A-485 potently inhibits proliferation of SOX10+ melanoma cells while decreasing invasion in AXLhigh/MITFlow melanoma cells through downregulation of metastasis-related genes. We conclude that the SOX10/p300 axis is critical to melanoma growth and invasion, and that inhibition of p300 KAT activity through A-485 may be a worthwhile therapeutic approach for SOX10-reliant tumors.

cancer biology↗

bioRxiv2024

The p300 KAT inhibitor, A-485, inhibits melanogenesis and melanin content in human melanocytes

Hyperpigmentation disorders are commonly diagnosed dermatologic conditions that can be cosmetically distressing for patients and cause negative psychosocial impacts. There is a need to better understand the underlying pathophysiology of pigmentary disorders as well as develop improvements in the management of these disorders. Here, we evaluated a p300 (CBP/p300) histone acetyltransferase (HAT) inhibitor, A-485, to determine if epigenetically targeting melanogenesis could be of therapeutic value. We find that A-485 treatment of primary human melanocytes and SK-MEL-30 melanoma cells drastically reduces the mRNA and protein expression of MITF and DCT, genes involved in melanin synthesis, and that this is accompanied by a reduction in melanin content. These results suggest that epigenetically targeting melanin synthesis with the A-485 p300 HAT inhibitor may be beneficial for the treatment of hyperpigmentation disorders.

cell biology↗

bioRxiv2020

The CoREST Repressor Complex Mediates Phenotype Switching and Therapy Resistance in Melanoma

Virtually all patients with BRAF-mutant melanoma develop resistance to MAPK inhibitors largely through non-mutational events1,2. Although the epigenetic landscape has been shown to be altered in therapy-resistant melanomas and other cancers3,4, a specific targetable epigenetic mechanism regulating treatment resistance has not been validated to date. Here we evaluate the CoREST repressor complex and the novel inhibitor, corin5, within the context of melanoma phenotype plasticity and therapeutic resistance in order to define epigenetic mechanisms underlying these processes. We find that CoREST is a critical mediator of the major distinct melanoma phenotypes and that corin treatment of melanoma cells leads to phenotype reprogramming. We further demonstrate that treatment of BRAF inhibitor (BRAFi)-resistant melanomas with corin leads to resensitization of tumor cells to BRAFi. Among the transcriptional targets of CoREST in melanoma are the dual-specificity phosphatases (DUSPs). DUSP1 is shown to be consistently downregulated in BRAFi-resistant melanomas which can be reversed by corin treatment, thereby leading to downstream inhibition of p38 MAPK activity and resensitization of resistant cells to targeted BRAFi therapies. These findings identify the CoREST repressor complex as a central mediator of melanoma phenotype plasticity and resistance to targeted therapy and suggest that CoREST inhibitors may prove beneficial to patients with BRAF-mutant melanomas who have acquired BRAFi-resistance.

cancer biology↗