Pediatric medulloblastoma (MB) is the most common solid malignant brain neoplasm, with Group 3 (G3) MB representing the most aggressive subgroup. MYC amplification is an independent poor prognostic ...factor in G3 MB, however, therapeutic targeting of the MYC pathway remains limited and alternative therapies for G3 MB are urgently needed. Here we show that the RNA-binding protein, Musashi-1 (MSI1) is an essential mediator of G3 MB in both MYC-overexpressing mouse models and patient-derived xenografts. MSI1 inhibition abrogates tumor initiation and significantly prolongs survival in both models. We identify binding targets of MSI1 in normal neural and G3 MB stem cells and then cross referenced these data with unbiased large-scale screens at the transcriptomic, translatomic and proteomic levels to systematically dissect its functional role. Comparative integrative multi-omic analyses of these large datasets reveal cancer-selective MSI1-bound targets sharing multiple MYC associated pathways, providing a valuable resource for context-specific therapeutic targeting of G3 MB.
d-chiroinositol (DCI) is a inositolphosphoglycan (IPG) involved in several cellular functions that control the glucose metabolism. DCI functions as second messenger in the insulin signaling pathway ...and it is considered an insulin sensitizer since deficiency in tissue availability of DCI were shown to cause insulin resistance (IR). Polycystic ovary syndrome (PCOS) is a pathological condition that is often accompanied with insulin resistance. DCI can positively affects several aspect of PCOS etiology decreasing the total and free testosterone, lowering blood pressure, improving the glucose metabolism and increasing the ovulation frequency. The purpose of this study was to evaluate the effects of DCI and insulin combined with gonadotrophins namely follicle-stimulating hormone (FSH) and luteinizing hormone (LH) on key steroidogenic enzymes genes regulation, cytochrome P450 family 19 subfamily A member 1 (CYP19A1) and cytochrome P450 side-chain cleavage (P450scc) in primary cultures of human granulosa cells (hGCs). We also investigated whether DCI, being an insulin-sensitizer would be able to counteract the expected stimulator activity of insulin on human granulosa cells (hGCs).
The study was conducted on primary cultures of hGCs. Gene expression was evaluated by RT-qPCR method. Statistical analysis was performed applying student t-test, as appropriate (P < 0.05) set for statistical significance.
DCI is able to reduce the gene expression of CYP19A1, P450scc and insulin-like growth factor 1 receptor (IGF-1R) in dose-response manner. The presence of DCI impaired the increased expression of steroidogenic enzyme genes generated by the insulin treatment in gonadotrophin-stimulated hGCs.
Insulin acts as co-gonadotrophin increasing the expression of steroidogenic enzymes genes in gonadotrophin-stimulated granulosa cells. DCI is an insulin-sensitizer that counteracts this action by reducing the expression of the genes CYP19A1, P450scc and IGF-1R. The ability of DCI to modulate in vitro ovarian activity of insulin could in part explain its beneficial effect when used as treatment for conditions associated to insulin resistance.
ATRX is a chromatin remodelling factor found at a wide range of tandemly repeated sequences including telomeres (TTAGGG)n. ATRX mutations are found in nearly all tumours that maintain their telomeres ...via the alternative lengthening of telomere (ALT) pathway, and ATRX is known to suppress this pathway. Here, we show that recruitment of ATRX to telomeric repeats depends on repeat number, orientation and, critically, on repeat transcription. Importantly, the transcribed telomeric repeats form RNA–DNA hybrids (R‐loops) whose abundance correlates with the recruitment of ATRX. Here, we show loss of ATRX is also associated with increased R‐loop formation. Our data suggest that the presence of ATRX at telomeres may have a central role in suppressing deleterious DNA secondary structures that form at transcribed telomeric repeats, and this may account for the increased DNA damage, stalling of replication and homology‐directed repair previously observed upon loss of ATRX function.
Synopsis
This study shows that ATRX recruitment to G‐rich tandem repeats depends on repeat transcription, length and orientation and is associated with R‐loops. ATRX loss increases R‐loops at these sites suggesting that ATRX resolves DNA secondary structures.
Recruitment of ATRX at G‐rich tandem repeats depends on transcription and is associated with the presence of R‐loops.
ATRX recruitment depends on the non‐template strand being G‐rich suggesting the presence of G quadruplex DNA.
R‐loops at these sites increase in the absence of ATRX.
This study shows that ATRX recruitment to G‐rich tandem repeats depends on repeat transcription, length and orientation and is associated with R‐loops. ATRX loss increases R‐loops at these sites suggesting that ATRX resolves DNA secondary structures.
Potency monitoring of CAR T cells Wang, Dongrui; Yang, Xin; Xella, Agata ...
Methods in cell biology,
2023, Volume:
173
Journal Article
Peer reviewed
The effector potency of chimeric antigen receptor (CAR) T cell therapeutic products is essential to their clinical antitumor responses, and potency monitoring is a critical quality control method for ...CAR T cell therapy platforms. While many in vitro assays enable high-throughput assessment of CAR T cell cytotoxicity, it has been challenging for these assays to reflect the in vivo therapeutic effect due to their nature as short-term methods that fail to recapitulate the high tumor burden environment. Here, we describe two in vitro co-culture methods to evaluate CAR T cell recursive killing potential at high tumor cell loads. In these assays, long-term cytotoxic function and proliferative capacity of CAR T cells are examined in vitro over 7days. Further, these assays are coupled with profiling CAR T cell expansion, cytokine production and phenotypes. These methods provide a facile approach to assess CAR T cell potency and to elucidate the functional variations across different CAR T cell products.
Direct‐write vapor deposition is a new technique that would enable one‐step 3D maskless nanofabrication on a variety of substrates. A novel silicon chip‐based microevaporator is developed that allows ...evaporant to exit through 2000–300 nm nozzles while held at distances comparable to the nozzle diameter from the substrate by a three‐axis nanopositioning stage in vacuum. This results in a localized deposition on the substrate, which may be scanned relative to the substrate to produce direct‐write patterns. The performance of the microevaporator is tested by creating localized depositions of various materials and the line‐writing potential is demonstrated. The relationship between linewidth and source‐to‐substrate distance is investigated by the application of Knudsen's cosine law and Monte‐Carlo simulations, and then utilized to approximate the source‐to‐substrate distance from performed depositions.
A silicon‐based microevaporator is developed for maskless patterning of thin films by direct‐write vapor deposition. It allows material to exit via 2 to 0.3 μm diameter nozzles to deposit on a substrate. Used with a scanning stage, writing of 1 μm diameter dots and 2 μm wide lines is demonstrated. (The table of contents figure is an artistic rendition using stitched microscopy images and graphics).
Purpose
Anti-Müllerian hormone
(
AMH
) and
forkhead box L2
(
FOXL2
) are two pivotal genes expressed in human granulosa cells (hGCs) where both genes share similar inhibitory functions on activation ...and follicular growth in order to preserve the ovarian follicle reserve. Furthermore, AMH and FOXL2 contribute to inhibit steroidogenesis, decreasing or preventing the activation of gonadotrophin-dependent aromatase CYP19A1 cytochrome P450 family 19 subfamily A member 1 (CYP19A1). The purpose of this study is to evaluate the role of AMH in regulating the expression of FOXL2.
Methods
Primary cultures of hGCs were treated with increasing concentrations of recombinant human AMH (rhAMH; range 10–100 ng/ml) for 3 h. Negative controls were performed using corresponding amounts of AMH vehicle. Total RNA or proteins were purified and quantified by spectrophotometry.
FOXL2
and
CYP19A1
gene expression, normalized by reference gene
ribosomal protein S7
(
RpS7
), was evaluated by RT-qPCR. Each reaction was repeated in triplicate. Statistical analysis was performed. Extracted proteins were analyzed by immunoblot using anti-FOXL2 and anti-β-actin as primary antibodies.
Results
rhAMH treatments tested did not modulate the basal expression of aromatase CYP19A1 gene. rhAMH (50 ng/ml) was able to increase
FOXL2
gene expression and its intracellular content.
Conclusions
This study demonstrated the existence of an AMH-FOXL2 relationship in hGCs. AMH is capable of increasing both gene and protein expression of FOXL2. Because FOXL2 induces
AMH
transcription, these ovarian factors could be finely regulated by a positive feedback loop mechanism to preserve the ovarian follicle reserve.
BackgroundMeditope is a small cyclic peptide that was identified to bind to cetuximab within the Fab region. The meditope binding site can be grafted onto any Fab framework, creating a platform to ...uniquely and specifically target monoclonal antibodies. Here we demonstrate that the meditope binding site can be grafted onto chimeric antigen receptors (CARs) and utilized to regulate and extend CAR T cell function. We demonstrate that the platform can be used to overcome key barriers to CAR T cell therapy, including T cell exhaustion and antigen escape.MethodsMeditope-enabled CARs (meCARs) were generated by amino acid substitutions to create binding sites for meditope peptide (meP) within the Fab tumor targeting domain of the CAR. meCAR expression was validated by anti-Fc FITC or meP-Alexa 647 probes. In vitro and in vivo assays were performed and compared to standard scFv CAR T cells. For meCAR T cell proliferation and dual-targeting assays, the meditope peptide (meP) was conjugated to recombinant human IL15 fused to the CD215 sushi domain (meP-IL15:sushi) and anti-CD20 monoclonal antibody rituximab (meP-rituximab).ResultsWe generated meCAR T cells targeting HER2, CD19 and HER1/3 and demonstrate the selective specific binding of the meditope peptide along with potent meCAR T cell effector function. We next demonstrated the utility of a meP-IL15:sushi for enhancing meCAR T cell proliferation in vitro and in vivo. Proliferation and persistence of meCAR T cells was dose dependent, establishing the ability to regulate CAR T cell expansion using the meditope platform. We also demonstrate the ability to redirect meCAR T cells tumor killing using meP-antibody adaptors. As proof-of-concept, meHER2-CAR T cells were redirected to target CD20+ Raji tumors, establishing the potential of the meditope platform to alter the CAR specificity and overcome tumor heterogeneity.ConclusionsOur studies show the utility of the meCAR platform for overcoming key challenges for CAR T cell therapy by specifically regulating CAR T cell functionality. Specifically, the meP-IL15:sushi enhanced meCAR T cell persistence and proliferation following adoptive transfer in vivo and protects against T cell exhaustion. Further, meP-ritiuximab can redirect meCAR T cells to target CD20-tumors, showing the versatility of this platform to address the tumor antigen escape variants. Future studies are focused on conferring additional ‘add-on’ functionalities to meCAR T cells to potentiate the therapeutic effectiveness of CAR T cell therapy.
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