RMS Patients Research Articles

The role of disease modifying therapies in late-onset MS: a Portuguese multicentric characterization study

IntroductionKnowledge about the effect of disease modifying treatment (DMT) in late-onset multiple sclerosis (LOMS, onset ≥50 years-old) is scarce. This study aims to evaluate the association between DMT use and multiple sclerosis (MS) evolution in a LOMS cohort. MethodsThis multicentre, retrospective and observational study included LOMS patients with ≥2 years of follow-up. Data on demographics, clinical/paraclinical (baseline and follow-up), DMT and adverse events were collected. Primary outcomes were irreversible EDSS 4.0 and 6.0 achievement and first year ARR. Univariate and multivariate regression models were conducted, with treated and/or relapsing phenotypes (RMS) subgroups analyses. ResultsWe included 232 patients (53.4% with RRMS phenotype; 84.9% submitted to DMT; median follow-up time of 141.5 (IQR 92.7-193.1) months). Treatment versus non-treatment did not affect EDSS milestones in multivariate analysis (adjusted to phenotype, baseline EDSS, age, and ARR), but initially receiving monoclonal antibodies (MAbs) was associated with lower odds of EDSS 4.0 (OR 0.13). In treated patients, starting with high efficacy DMT (HE-DMT) was related to a lower chance of EDSS 4.0 (OR 0.05) and 6.0 (OR 0.26) compared with being exclusively treated with moderate efficacy DMT (ME-DMT), with similar results when analysing the subgroup of RMS treated patients. In multivariate models, initial treatment with MAbs (vs. non-treatment) and with HE-DMT (vs. ME-DMT) were related to a lower first year ARR; when considering only RMS patients, every DMT class analysed reduced first year ARR vs. non-treatment. During DMT, we documented a rate of 0.6% serious infections, 0.07% opportunistic infections and 0.7% neoplasm diagnosis per patient year. ConclusionDMT type and therapeutic strategy influenced LOMS disability accumulation and relapses in our cohort. Our findings support the importance of investment in LOMS treatment optimization.

Plasma-derived extracellular vesicles miR-335–5p as potential diagnostic biomarkers for fusion-positive rhabdomyosarcoma

BackgroundRhabdomyosarcoma (RMS) is the most common pediatric soft tissue sarcoma, with embryonal (ERMS) and alveolar (ARMS) representing the two most common histological subtypes. ARMS shows poor prognosis, being often metastatic at diagnosis. Thus, the discovery of novel biomarkers predictive of tumor aggressiveness represents one of the most important challenges to overcome and may help the development of tailored therapies. In the last years, miRNAs carried in extracellular vesicles (EVs), small vesicles of endocytic origin, have emerged as ideal candidate biomarkers due to their stability in plasma and their tissue specificity.MethodsEVs miRNAs were isolated from plasma of 21 patients affected by RMS and 13 healthy childrens (HC). We performed a miRNA profile using the Serum/Plasma Focus microRNA PCR panels (Qiagen), and RT-qPCR for validation analysis. Statistically significant (p < 0.05) miRNAs were obtained by ANOVA test.ResultsWe identified nine EVs miRNAs (miR-483-5p, miR-132-3p, miR-766-3p, miR-454-3p miR-197-3p, miR-335-3p, miR-17-5p, miR-486-5p and miR-484) highly upregulated in RMS patients compared to HCs. Interestingly, 4 miRNAs (miR-335-5p, miR-17-5p, miR-486-5p and miR-484) were significantly upregulated in ARMS samples compared to ERMS. In the validation analysis performed in a larger group of patients only three miRNAs (miR-483-5p, miR-335-5p and miR-484) were differentially significantly expressed in RMS patients compared to HC. Among these, mir-335-5p was significant also when compared ARMS to ERMS patients. MiR-335-5p was upregulated in RMS tumor tissues respect to normal tissues (p = 0.00202) and upregulated significantly between ARMS and ERMS (p = 0.04). Furthermore, the miRNA expression correlated with the Intergroup Rhabdomyosarcoma Study (IRS) grouping system, (p = 0.0234), and survival (OS, p = 0.044; PFS, p = 0.025). By performing in situ hybridization, we observed that miR-335-5p signal was exclusively in the cytoplasm of cancer cells.ConclusionWe identified miR-335-5p as significantly upregulated in plasma derived EVs and tumor tissue of patients affected by ARMS. Its expression correlates to stage and survival in patients. Future studies are needed to validate miR-335-5p as prognostic biomarker and to deeply elucidate its biological role.

Massive Bone Marrow Infiltration by Disseminated Alveolar Rhabdomyosarcoma Mimicking Acute Leukemia.

RMS is a malignant tumor of soft tissues affecting primarily children and adolescents. Around 6% to 23% RMS patients present bone marrow infiltration but leukemia-like involvement is very rare; in these patients cytomorphology on bone marrow smears can lead to misdiagnosis. Differential diagnosis with alveolar RMS should be kept in mind in every pediatric patient presenting with a marked bone marrow involvement in the absence of typical lymphoproliferative findings.

Localized incompletely resected standard risk rhabdomyosarcoma in children and adolescents: Results from the European Paediatric Soft Tissue Sarcoma Study Group RMS 2005 trial.

The authors report the prospective evaluation of reduced dose alkylator chemotherapy combined with radiotherapy for European Pediatric Soft Tissue Sarcoma Study Group (EpSSG) standard risk nonalveolar rhabdomyosarcoma (NA-RMS). Localized node negative Intergroup Rhabdomyosarcoma Study (IRS) II/III NA-RMS at favorable sites (subgroup C), <25 years old, received five cycles of ifosfamide, vincristine, and dactinomycin (IVA) chemotherapy (30 g/m2 ifosfamide) and four cycles of vincristine and dactinomycin (if receiving radiotherapy), or nine cycles of IVA (54 g/m2 ifosfamide) ± radiotherapy. Delayed primary tumor excision was considered for IRS III tumors. The primary end points were event-free survival (EFS) and overall survival (OS). From October 2005 to December 2016, 359 evaluable patients were recruited: orbit, 164 (45.7%); head and neck nonparameningeal, 77 (21.4%); and genitourinary non-bladder/prostate, 118 (32.9%). EFS and OS were 77.4% (95% confidence interval [CI], 72.5-81.6) and 93.5% (95% CI, 90.1-95.8), respectively. Lower dose alkylator chemotherapy and radiotherapy achieved 5-year OS of 93.7% but the difference with higher dose alkylator chemotherapy +/- radiotherapy was not significant (p=0.8003). Adjuvant radiotherapy improved EFS with 5-year estimates of 84.7% versus 65.2% for nonirradiated (p<.0001), but not OS (p=.9298). Omitting radiotherapy for orbital tumors reduced OS (5-year was 87.1% vs. 97.3% for irradiated, p=.0257). Following R0 resection (n=60), radiotherapy did not significantly improve EFS or OS. Radiotherapy for local tumor control allows for reduction of cumulative dose of alkylators in EpSSG standard risk subgroup C RMS patients. The omission of radiotherapy did not affect OS in all patients except those with orbital RMS and was associated with inferior EFS.

The deubiquitinase USP7 and E3 ligase TRIM21 regulate vasculogenic mimicry and malignant progression of RMS by balancing SNAI2 homeostasis

BackgroundRhabdomyosarcoma (RMS) is a rare malignancy and the most common soft tissue sarcoma in children. Vasculogenic mimicry (VM) is a novel tumor microcirculation model different from traditional tumor angiogenesis, which does not rely on endothelial cells to provide sufficient blood supply for tumor growth. In recent years, VM has been confirmed to be closely associated with tumor progression. However, the ability of RMS to form VM has not yet been reported.MethodsImmunohistochemistry, RT-qPCR and western blot were used to test the expression level of SNAI2 and its clinical significance. The biological function in regulating vasculogenic mimicry and malignant progression of SNAI2 was examined both in vitro and in vivo. Mass spectrometry, co-immunohistochemistry, immunofluorescence staining, and ubiquitin assays were performed to explore the regulatory mechanism of SNAI2.ResultsOur study indicated that SNAI2 was abnormally expressed in patients with RMS and RMS cell lines and promoted the proliferation and metastasis of RMS. Through cell tubule formation experiments, nude mice Matrigel plug experiments, and immunohistochemistry (IHC), we confirmed that RMS can form VM and that SNAI2 promotes the formation of VM. Due to SNAI2 is a transcription factor that is not easily drugged, we used Co-IP combined with mass spectrometry to screen for the SNAI2-binding protein USP7 and TRIM21. USP7 depletion inhibited RMS VM formation, proliferation and metastasis by promoting SNAI2 degradation. We further demonstrated that TRIM21 is expressed at low levels in human RMS tissues and inhibits VM in RMS cells. TRIM21 promotes SNAI2 protein degradation through ubiquitination in the RMS. The deubiquitinase USP7 and E3 ligase TRIM21 function in an antagonistic rather than competitive mode and play a key role in controlling the stability of SNAI2 to determine the VM formation and progression of RMS.ConclusionOur findings reveal a previously unknown mechanism by which USP7 and TRIM21 balance the level of SNAI2 ubiquitination, determining RMS vasculogenic mimicry, proliferation, and migration. This new mechanism may provide new targeted therapies to inhibit the development of RMS by restoring TRIM21 expression or inhibiting USP7 expression in RMS patients with high SNAI2 protein levels.

Exosome-Mediated Paracrine Signaling Unveils miR-1246 as a Driver of Aggressiveness in Fusion-Negative Rhabdomyosarcoma.

Rhabdomyosarcoma is a pediatric cancer associated with aggressiveness and a tendency to develop metastases. Fusion-negative rhabdomyosarcoma (FN-RMS) is the most commonly occurring subtype of RMS, where metastatic disease can hinder treatment success and decrease survival rates. RMS-derived exosomes were previously demonstrated to be enriched with miRNAs, including miR-1246, possibly contributing to disease aggressiveness. We aimed to decipher the functional impact of exosomal miR-1246 on recipient cells and its role in promoting aggressiveness. Treatment of normal fibroblasts with FN-RMS-derived exosomes resulted in a significant uptake of miR-1246 paired with an increase in cell proliferation, migration, and invasion. In turn, delivery of miR-1246-mimic lipoplexes promoted fibroblast proliferation, migration, and invasion in a similar manner. Conversely, when silencing miR-1246 in FN-RMS cells, the resulting derived exosomes demonstrated reversed effects on recipient cells' phenotype. Delivery of exosomal miR-1246 targets GSK3β and promotes β-catenin nuclear accumulation, suggesting a deregulation of the Wnt pathway, known to be important in tumor progression. Finally, a pilot clinical study highlighted, for the first time, the presence of high exosomal miR-1246 levels in RMS patients' sera. Altogether, our results demonstrate that exosomal miR-1246 has the potential to alter the tumor microenvironment of FN-RMS cells, suggesting its potential role in promoting oncogenesis.

Abstract LB404: ATR inhibitors synergize with DHFR inhibitors in rhabdomyosarcoma cells by disrupting DNA damage checkpoint

Abstract Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and adolescents. RMS tumors are classified into four subtypes: embryonal, alveolar, spindle cell/sclerosing, and pleomorphic. Treatment options for RMS include a combination of surgery, chemotherapy, and radiation therapy and regimens for patients with relapsed and metastatic RMS remain limited. However, a recent study has reported that pharmacological inhibitors targeting ataxia telangiectasia and Rad3-related protein (ATR) are currently undergoing phase I/II trials and may be utilized for the treatment of alveolar RMS. Interestingly, we identified that the gene signature of replication stress positively correlated with dihydrofolate reductase (DHFR) expression in the cancer cell line database (CellMinerCDB, discover.nci.nih.gov/cellminercdb; Pearson correlation (r)=0.66). DHFR is an important therapeutic target for cancer and autoimmune diseases, and its inhibitors are routinely used and clinically approved. DHFR inhibitors are known to exhibit their anticancer effects by inhibiting nucleotide synthesis and DNA replication. In this study, we aimed to explore a potential synergistic interaction using a combination treatment of ATR inhibitors (elimusertib and ceralasertib) and DHFR inhibitors (pralatrexate, methotrexate, and raltitrexated) in multiple RMS cell lines. We used a drug matrix reduction format and found that combined treatment of ATR inhibitors and DHFR inhibitors induced a synergistically decreased RMS cell viability, showing higher synergy in fusion-positive RMS cells than in fusion-negative RMS cells. Mechanistically, ATR inhibitors abrogated DNA damage response checkpoint CHK1 activation caused by DHFR inhibitor, leading to increased γH2AX and decreased DNA replication activity. Accordingly, the accumulation of DNA damage in combination with ATR inhibitor and DHFR inhibitor triggered higher cell cycle arrest and apoptotic cell death than single agent treatment of DHFR inhibitor. Our findings warrant further research into identifying genomic regions where the DNA damage is enriched in combination treatment by using END-sequencing and synthesis-associated with repair sequencing (SAR-seq). In conclusion, this study provides promising rationale for the combination treatment of ATR and DHFR inhibitors to treat RMS patients, including those with advanced, relapsed, and metastatic states. Citation Format: Ukhyun Jo, George K Annor, Jack F. Shern. ATR inhibitors synergize with DHFR inhibitors in rhabdomyosarcoma cells by disrupting DNA damage checkpoint [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB404.

Abstract 711: HDAC3 sustains resistance to hypofractionated radiotherapy in fusion positve rhabdomyosarcoma cells

Abstract Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood. The fusion-positive (FP)-RMS variant expressing chimeric oncoproteins such as PAX3-FOXO1 and PAX7-FOXO1 shows a dismal prognosis with 5-year survival of less than 30% compared to non-metastatic fusion-negative (FN)-RMS variant. In the last years, a lot of interest has focused on new targets identification to improve the radiotherapy (RT) efficacy. HDAC inhibitors (HDACi) radio-sensitize different cancer cell types including RMS. Recently, we reported that MS-275, a Class I and IV HDACi, in combination with RT affected cell survival, reduced colony formation ability, increased DNA damage repair inhibition and reactive oxygen species formation in FP-RMS cells. However, despite promising preclinical studies, HDAC inhibitors (HDACi) achieved only modest success in human clinical trials for solid tumors, frequently showing several toxicities, probably because of the limited specificity of many HDACi. Thus, a major effort is being directed toward identification of HDACi which are selective for HDAC isoforms often uniquely implicated in the radioresistance of specific cancers. In order to identify the class I HDAC responsible of radioresistance in RMS we knocked-down HDAC1, HDAC2, HDAC3, and HDAC8 expression in combination with RT. Interestingly, we observed an increased radiosensitivity only in HDAC3-depleted FP-RMS cells. Thus, we focused on HDAC3 to understand the mechanisms by which it promotes radioresistance in RMS. We observed that HDAC3 is overexpressed in RMS patients and cell lines compared to the normal counterpart. Furthermore, RMS cells are strongly dependent by HDAC3 expression while slight dependency has been observed with other class I HDACs in DepMap portal. We demonstrated that HDAC3 depletion by CRISPR in combination with RT in FP-RMS cells increases apoptosis, reduces colony formation ability, cancer stem cells population and anchorage independent growth and reduces cell growth in vivo and in vitro. Accordingly, HDAC3 depleted cells in combination with RT reduces levels and activation of key player of FP-RMS biology such as MYCN, ERK and AKT. Moreover, HDAC3 KD increases radiotherapy-induced DNA double strand break and impairs DNA repair mechanisms reducing levels and activation of both homologous recombination (HR) and non-homologous end joining (NHEJ) factors such as ATM, RAD51 and DNA-PKcs. Thus, we developed a new potent and highly specific HDAC3 inhibitor (HDAC3i). The new HDAC3i is highly specific in targeting FP-RMS cell growth in vitro while no effects have been observed in normal cells such as myoblasts and lung fibroblast. Moreover, the drug treatment in combination with radiotherapy phenotypically and molecularly recapitulated what observed in HDAC3 depleted cells.The study has been founded by Italian Association for Cancer Research (AIRC) to FM. Citation Format: Matteo Cassandri, Antonella Porrazzo, Silvia Pomella, Simona Camero, Francesca A. Aiello, Lucrezia D'Archivio, Clemens Zwergel, Beatrice Noce, Miriam Tomaciello, Francesca Vulcano, Luisa Milazzo, Francesca Pedini, Michele Signore, Alessandro Fanzani, Cinzia Marchese, Giuseppe Minniti, Sergio Valente, Antonello Mai, Francesca Megiorni, Rossella Rota, Francesco Marampon. HDAC3 sustains resistance to hypofractionated radiotherapy in fusion positve rhabdomyosarcoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 711.

Abstract 2863: CDKN1A prevents IR-induced apoptosis in rhabdomyosarcoma tumor via repressing the pro-apoptotic factor NOXA in a novel apoptotic regulatory axis

Abstract Rhabdomyosarcoma (RMS) is a tumor of the muscle and is the most common soft tissue cancer in children and teens, with approximately 400 to 500 new cases every year in the United States. While we have a good understanding of the interplay between pro- and anti-apoptotic regulators, much remains to be learned about how the decision to trigger apoptosis or not is controlled at the transcriptional level in RMS tumors. We strive to elucidate how pathways that drive apoptosis avoidance are epi-genetically pre-programmed in cells. We have discovered that SNAI2, a transcriptional repressor, acts as a master switch to either activate or dampen apoptosis in response to ionizing radiation (IR). While elevated SNAI2 results in transcriptional repression of the pro-apoptotic factor BIM and protection from apoptosis post-IR, a small number of SNAI2 null cells survive radiation to reproliferate in vivo, revealing the existence of hitherto unappreciated mechanisms that support the survival of irradiated cells. Hence, we hypothesized that there are additional genes or pathways in cells lacking SNAI2 that are co-opted to drive relapse disease. We have identified that CDKN1A or p21 expression is robustly increased in SNAI2 null cells. CDKN1A is thought to be a tumor suppressor. However, our preliminary data indicate that CDKN1A is an oncogene, and in RMS patients, high tumor expression is associated with poor outcomes. We found that CDKN1A expression in combination with SNAI2 can predict resistance to radiation across RMS cell lines. We next developed control RD, Rh30, and Rh18 cells, either CDKN1A or both CDKN1A and SNAI2 ablated using CRISPR/Cas9 reagents with control cells expressing control gRNAs. Ablation of CDKN1A, while not affecting proliferation, led to a significant increase in apoptosis post-radiation, and this effect was increased in SNAI2/CDKN1A double knockout cells. Further, in colony-forming assays, we find that double-ablated cells form significantly fewer colonies than control and single knockout cells. Loss of CDKN1A, SNAI2, or CDKN1A/SNAI2 led to a G2/M cell cycle block, indicating that the cell cycle effects of p21 might not be responsible for the phenotypes observed. Ongoing xenograft experiments have determined the effect we observe in vitro will also translate in vivo. Given that SNAI2 and CDKN1A are heterogeneously expressed, respectively, we will interrogate CDKN1A for its role in protecting differentiated cells from apoptosis. We will determine if CDKN1A prevents apoptosis by repressing the pro-apoptotic factor NOXA in a novel apoptotic regulatory axis specific to differentiated cells. Our study will show that critical primary and alternative apoptosis resistance mechanisms are epi-genetically pre-programmed in cells by SNAI2. Citation Format: Paulomi S. Modi, Myron Ignatius, Long Wang, Prethish Sreenivas. CDKN1A prevents IR-induced apoptosis in rhabdomyosarcoma tumor via repressing the pro-apoptotic factor NOXA in a novel apoptotic regulatory axis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2863.

Abstract 4738: Overcoming therapy resistance in rhabdomyosarcoma by targeting the PI3K-MAPK pathway

Abstract Rhabdomyosarcoma (RMS) is a devastating pediatric cancer. There has not been any significant change in the treatment options for the last 4 decades, especially for relapsed or advanced disease. There is an urgent need to identify alternative treatment options to improve survival outcomes of RMS patients. RMS is comprised of two major subtypes as defined by the presence or absence of PAX3/PAX7-FOXO1 gene fusion. Fusion-negative RMS (FN RMS) is characterized by alterations in the RAS-PI3K-MAPK pathway in &amp;gt;90% of the cases. However, the role of the PI3K-MAPK pathway in therapy resistance and disease relapse remains poorly characterized. We have generated two FN-RMS lines, RD and SMS-CTR, with resistance to the standard-of-care chemotherapeutic agent, vincristine, through long-term culturing in incrementally increased concentrations of the drug. By RNA sequencing, vincristine-resistant RD and SMS-CTR cells demonstrated increased expression of genes in the RAS-PI3K-MAPK pathway compared to the parental lines. We hypothesize that increased activity of the PI3K-MAPK pathway contributes to therapy resistance in FN RMS. To test the hypothesis, we first showed that targeted disruption of PIK3CA by shRNA inhibited the cell growth of vincristine-resistant FN RMS cells. The same cells also showed increased sensitivity to the MEK inhibitor, trametinib, as well as the PIK3Cα inhibitor, alpelisib, compared to the parental cells. We then showed that zebrafish FN-RMS tumors treated with the combination of vincristine and alpelisib significantly inhibited tumor growth compared to the treatment with each agent alone. Through integrative analysis of RNA sequencing and ATAC-seq data, we identified MYOD1 and NFATC2 as among the top candidate upstream regulators. Targeted disruption of either MYOD1 or NFATC2 by CRISPR/Cas9 reduced cell growth of vincristine-resistant FN RMS cells and altered expression of the genes in the PI3K-MAPK pathway, implicating MYOD1 and NFATC2 in driving abnormal activity of this pathway. To assess the relevance of our findings in the clinical settings, we showed that selective components in the PI3K-MAPK pathways are up-regulated in 3 matched primary-recurrence/metastasis paraffinized tissue samples of human FN RMS by the NanoString GeoMx Digital Spatial Profiler (DSP) platform. Our findings indicate that targeting the PI3K-MAPK pathway is a promising targeted therapy option for overcoming therapy resistance in RMS. Citation Format: Yadong Wang, Eleanor Chen. Overcoming therapy resistance in rhabdomyosarcoma by targeting the PI3K-MAPK pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4738.

Substantial and comparable suppression of disease activity following early initiation of cladribine tablets, ocrelizumab or alemtuzumab as first pharmacologic treatment for relapsing multiple sclerosis: A real world study

BackgroundWe describe the efficacy and safety of recent high efficacy disease DMTs in DMT-naive patients with highly active RMS. MethodsThis was a retrospective, cross sectional study from the Kuwait national MS registry. Patients with RMS who received alemtuzumab, cladribine tablets or ocrelizumab as their first DMT for RMS, with ≥2 year of follow up were included. The primary endpoint was the change in relapse rate from treatment initiation to 1 year; changes in disability (Expanded Disability Status Scale [EDSS]), radiologic activity, the proportion with no evidence of disease activity-3 (NEDA-3), and the frequency of adverse events were secondary endpoints. ResultsAmong 123 RRMS patients, 59 received ocrelizumab, 32 received cladribine tablets and 32 received alemtuzumab. About two-thirds (65%) were women. Substantial and similar (p>0.05) reductions occurred at the end of follow-up in annual relapse rate (by 93.2% for ocrelizumab, 87.5% for cladribine tablets, and 90.6% for alemtuzumab). The proportion with new T2 of gadolinium-enhancing MRI lesions across the three groups was reduced from 85–100% to 7–13%. Rates of confirmed disability progression were low (ocrelizumab 6.9%, cladribine tablets 3.1%, alemtuzumab 0%; p=0.280); disability was reduced in 15%, 22% and 38%, respectively. NEDA-3 was observed in 89.8%, 87.5%, and 84.4, respectively (p=0.784). No new or unexpected safety issues occurred. ConclusionOcrelizumab, cladribine tablets and alemtuzumab reduced relapse rates and MRI activity, and prevented disease progression, when are initiated early in DMT-naive RMS patients. These data support the early use of high-efficacy DMTs for people with highly active RMS.

Statin-Sensitive Akt1/Src/Caveolin-1 Signaling Enhances Oxidative Stress Resistance in Rhabdomyosarcoma.

Identifying the molecular mechanisms underlying radioresistance is a priority for the treatment of RMS, a myogenic tumor accounting for approximately 50% of all pediatric soft tissue sarcomas. We found that irradiation (IR) transiently increased phosphorylation of Akt1, Src, and Cav1 in human RD and RH30 lines. Synthetic inhibition of Akt1 and Src phosphorylation increased ROS levels in all RMS lines, promoting cellular radiosensitization. Accordingly, the elevated activation of the Akt1/Src/Cav1 pathway, as detected in two RD lines characterized by overexpression of a myristoylated Akt1 form (myrAkt1) or Cav1 (RDCav1), was correlated with reduced levels of ROS, higher expression of catalase, and increased radioresistance. We found that treatment with cholesterol-lowering drugs such as lovastatin and simvastatin promoted cell apoptosis in all RMS lines by reducing Akt1 and Cav1 levels and increasing intracellular ROS levels. Combining statins with IR significantly increased DNA damage and cell apoptosis as assessed by γ histone 2AX (γH2AX) staining and FACS analysis. Furthermore, in combination with the chemotherapeutic agent actinomycin D, statins were effective in reducing cell survival through increased apoptosis. Taken together, our findings suggest that the molecularly linked signature formed by Akt1, Src, Cav1, and catalase may represent a prognostic determinant for identifying subgroups of RMS patients with higher probability of recurrence after radiotherapy. Furthermore, statin-induced oxidative stress could represent a treatment option to improve the success of radiotherapy.

Treatment outcome of pediatric rhabdomyosarcoma at national cancer institute, Egypt

Background Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in infants and children. It is the third most common solid tumor in children after neuroblastoma and Wilms tumor, making up 10–15% of all solid pediatric tumors. At National Cancer Institute (NCI), Egypt, soft tissue sarcomas represent 3.75% of total malignancies and 27.6% of these occur in the pediatric group. RMS is the most common type. Aim and objectives This work aims to study the treatment outcome, overall survival (OS), and event free survival (EFS) of pediatric RMS patients diagnosed and treated at NCI. Patients and methods This is a retrospective study that included 54 pediatric patients, newly diagnosed with RMS who were treated at the pediatric oncology department, NCI, Cairo University, Egypt during the period from January 2012 to December 2016. Results Totally 54 pediatric patients with RMS with ages ranging from 7 months to 17 years (median age 5 years) were studied. The median follow-up period ranged with a minimum 1 year for the last patient. In this study, we classify our patients into low, intermediate, and high-risk groups according to IRS and we found that 11 (20.4%) patients were eligible for the low-risk group, 27 (50%) patients were eligible for the intermediate risk group and 16 (29.6%) patients were eligible for the high-risk group. The 2-year OS for low-risk group was 90.9%, it was 52.1% for intermediate-risk group, while it was 43.8% for high-risk group (P=0.02). The 2-year EFS for low-risk group was 63.6%, it was 41.2% for intermediate-risk group, while it was 31.3% for high-risk group (P=0.203). Conclusion RMS requires combined-modality therapy. Late presentation and advanced local disease compromise treatment options and decrease OS and EFS.

Evaluation of drivers of treatment switch in relapsing multiple sclerosis: a study from the Italian MS Registry.

Active relapsing-remitting (RR) and secondary progressive (SP) multiple sclerosis (MS) are currently defined as "relapsing MS" (RMS). The aim of this cross-sectional study was to assess drivers of treatment switches due to clinical relapses in a population of RMS patients collected in the Italian MS and Related Disorders Register (I-MS&RD). RRMS and SPMS patients with at least one relapse in a time window of 2years before of data extraction were defined as RMS. Factors associated with disease-modifying therapy (DMT) switching due to clinical activity were assessed through multivariable logistic regression models in which treatment exposure was included as the last recorded DMT and the last DMT's class [moderate-efficacy (ME), high-efficacy (HE) DMTs and anti-CD20 drugs]. A cohort of 4739 RMS patients (4161 RRMS, 578 SPMS) was extracted from the I-MS&RD. A total of 2694 patients switching DMTs due to relapses were identified. Switchers were significantly (p < 0.0001) younger, less disabled, more frequently affected by an RR disease course in comparison to non-switcher patients. The multivariable logistic regression models showed that Alemtuzumab (OR 0.08, 95% CI 0.02-0.37), Natalizumab (0.48, 0.30-0.76), Ocrelizumab (0.1, 0.02-0.45) and Rituximab (0.23, 0.06-0.82) exposure was a protective factor against treatment switch due to relapses. Moreover, the use of HE DMTs (0.43, 0.31-0.59), especially anti-CD20 drugs (0.14, 0.05-0.37), resulted to be a protective factor against treatment switch due to relapses in comparison with ME DMTs. More than 50% of RMS switched therapy due to disease activity. HE DMTs, especially anti-CD20 drugs, significantly reduce the risk of treatment switch.

What is the fuss about FUS fused rhabdomyosarcoma?

Abstract Introduction/Objective Rhabdomyosarcoma (RMS) is a rare and aggressive soft tissue sarcoma that primarily affects children and adolescents. It arises from primitive mesenchymal cells committed to skeletal muscle differentiation. Understanding the molecular drivers and genetic alterations underlying RMS is crucial for developing targeted therapies and improving patient outcomes. Recently, a novel fusion event involving the transcription factor CP2-like protein 2 (TFCP2) and fused in sarcoma (FUS) has emerged as a potential oncogenic driver in a subset of RMS cases. This fusion event represents a novel genetic alteration with implications for RMS pathogenesis, diagnosis, and therapeutic strategies. Methods/Case Report A 58-year-old female presented with a tender fullness along the right mandibular body. A biopsy performed at an outside institution was notable for a spindle cell neoplasm. She underwent resection of the lesion with pathology demonstrating a predominantly monomorphic spindle cell sarcoma with focal areas of pleomorphism. The lesion was diffusely positive for MyoD1. SOX10, S100, H-caldesmon, SMA, and pan-cytokeratin were negative. H3K27me3 was retained, arguing against malignant peripheral nerve sheath tumor with extensive rhabdomyoblastic differentiation. Break-apart FISH studies for FUS gene were positive. Overall, the findings were those of a recently described RMS variant with rearranged TFCP2 gene with FUS or EWSR1 as the partner gene. The patient later received adjuvant chemotherapy and radiotherapy. Despite that, her restaging scan 12 months later showed rapid progression with involvement of lungs, bone, and local recurrence in the jaw bilaterally. Results (if a Case Study enter NA) NA Conclusion TFCP2-FUS gene fusion drives an emerging family of RMS with a predilection for the jaws. Recognition of this rare entity can guide personalized therapeutic approaches and improve the prognostic stratification of RMS patients

The Development of Ofatumumab, a Fully Human Anti-CD20 Monoclonal Antibody for Practical Use in Relapsing Multiple Sclerosis Treatment.

The importance of B cells in multiple sclerosis (MS) has been demonstrated through the advent of B-cell-depleting anti-CD20 antibody therapies. Ofatumumab is the first fully human anti-CD20 monoclonal antibody (mAb) developed and tested for subcutaneous (SC) self-administration at monthly doses of 20mg, and has been approved in the US, UK, EU, and other regions and countries worldwide for the treatment of relapsing MS. The development goal of ofatumumab was to obtain a highly efficacious anti-CD20 therapy, with a safety and tolerability profile that allows for self-administration by MS patients at home and a positive benefit-risk balance for use in the broad relapsing MS population. This development goal was enabled by the unique binding site, higher affinity to B cells, and higher potency of ofatumumab compared to previous anti-CD20 mAbs; these properties of ofatumumab facilitate rapid B-cell depletion and maintenance with a low dose at a low injection volume (20mg/0.4ml). The high potency in turn enables the selective targeting of B cells that reside in the lymphatic system via subcutaneous (SC) administration. Through a comprehensive dose-finding program in two phase 2 studies (one intravenous and one SC) and model simulations, it was found that safety and tolerability can be further improved, and the risk of systemic injection-related reactions (IRRs) minimized, by avoiding doses≥30mg, and by reaching initial and rapid B-cell depletion via stepwise weekly administration of ofatumumab at Weeks 0, 1, and 2 (instead of a single high dose). Once near-complete B-cell depletion is reached, it can be maintained by monthly doses of 20mg/0.4ml. Indeed, in phase 3 trials (ASCLEPIOS I/II), rapid and sustained near-complete B-cell depletion (largely independent of body weight, race and other factors) was observed with this dosing regimen, which resulted in superior efficacy of ofatumumab versus teriflunomide on relapse rates, disability worsening, neuronal injury (serum neurofilament light chain), and imaging outcomes. Likely due to its fully human nature, ofatumumab has a low immunogenic risk profile-only 2 of 914 patients receiving ofatumumab in ASCLEPIOS I/II developed anti-drug antibodies-and this may also underlie the infrequent IRRs (20% with ofatumumab vs. 15% with the placebo injection in the teriflunomide arm) that were mostly (99.8%) mild to moderate in severity. The overall rates of infections and serious infections in patients treated with ofatumumab were similar to those in patients treated with teriflunomide (51.6% vs. 52.7% and 2.5% vs. 1.8%, respectively). The benefit-risk profile of ofatumumab was favorable compared to teriflunomide in the broad RMS population, and also in the predefined subgroups of both recently diagnosed and/or treatment-naïve patients, as well as previously disease-modifying therapy-treated patients. Interim data from the ongoing extension study (ALITHIOS) have shown that long-term treatment with ofatumumab up to 4years is well-tolerated in RMS patients, with no new safety risks identified. In parallel to the phase 3 trials in which SC administration was carried out with a pre-filled syringe, an autoinjector pen for more convenient self-administration of the ofatumumab 20mg dose was developed and is available for use in clinical practice.

Ocrelizumab extended-interval dosing in multiple sclerosis during SARS-CoV-2 pandemic: a real-world experience.

During the COVID-19 pandemic, ocrelizumab administration was frequently postponed because of a lack of safety information and to favour vaccination. The clinical implications of ocrelizumab administration delay in multiple sclerosis (MS) patients were assessed. Relapsing (RMS) and primary progressive (PPMS) MS patients receiving ocrelizumab for at least 6 months at our centre were retrospectively classified, according to the possible occurrence of a delay (≥4 weeks) in treatment administration. Patients were categorized in the extended-interval dosing (EID) group in the presence of at least one delayed infusion; otherwise they were considered as part of the standard interval dosing (SID) cohort. MS history, magnetic resonance imaging examinations and B-cell counts were also retrospectively collected and analysed. A total of 213 RMS and 61 PPMS patients were enrolled; 115 RMS and 29 PPMS patients had been treated according to the SID regimen, whilst 98 RMS and 32 PPMS patients were included in the EID cohort. Average follow-up after delay was 1.28 ± 0.7 years in the EID cohort. In RMS, comparing SID and EID patients, no differences were found considering the occurrence of clinical relapses (9.6% vs. 16.3%, p = 0.338), magnetic resonance imaging activity (9.8% vs. 14.1%, p = 0.374) or disability progression (11.3% vs. 18.4%, p = 0.103). Similar findings were observed in PPMS patients. In the pooled EID group, treatment delay correlated with CD19-positive relative (r = 0.530, p < 0.001) and absolute (r = 0.491, p < 0.001) cell counts, without implications on disease activity. Sporadic ocrelizumab administration delay granted sustained treatment efficacy in our cohort. Prospective data should be obtained to confirm these observations and set up systematic extended-interval regimens.

COVID-19 Antibody Response by Vaccine Type and Lymphocyte Count in RMS Patients on Ponesimod: Results From Phase 2 Long-term Extension Study AC-058B202 (P12-3.003)

COVID-19 Antibody Response by Vaccine Type and Lymphocyte Count in RMS Patients on Ponesimod: Results From Phase 2 Long-term Extension Study AC-058B202 (P12-3.003)

Abstract 1465: A SNAI2/CDKN1A pathway protects rhabdomyosarcoma tumors from radiation

Abstract Rhabdomyosarcoma (RMS) is tumor of the muscle and is the most common soft tissue cancer in children and teens, with approximately 400 to 500 new cases every year in the United States. There are two main subtypes of rhabdomyosarcoma: 1) Alveolar rhabdomyosarcoma (fusion-positive RMS FP-RMS), is classified primarily by the presence of the fusion between PAX3/PAX7 and FOXO1 proteins. 2) Embryonal rhabdomyosarcoma (fusion-negative FN-RMS) is the more common subtype. The survival rate for patients with RMS is 70%, but at relapse it is less than 30%. The standard of care for this disease includes radiation, chemotherapy and surgery. To better understand how RMS tumors survive therapy, we sought to define the role of SNAI2 in the response to radiation treatment. We identified SNAI2 as a critical oncogene that protects RMS tumors from radiation induced apoptosis by repressing pro-apoptotic BIM expression (Cancer Research 2021). SNAI2 additionally prevents FN-RMS tumors and cells from undergoing myogenic differentiation (Nature Comm. 2021). We also showed that MEK maintained SNAI2 post translationally in RAS mutant FN-RMS tumors and combining MEK inhibitor with radiation led to complete tumor regression and delayed event free survival in xenograft and PDX models. However, rare tumor cells grow back after a 2-4 weeks delay (Molecular Cancer Therapeutics, 2022). Hence, we hypothesized that there are additional genes or pathways in cells lacking SNAI2 that are co-opted to drive relapse disease. We have identified that CDKN1A or p21 expression is robustly increased in SNAI2 null cells. CDKN1A is thought to be a tumor suppressor in RMS and other cancers. However, our preliminary data indicate that CDKN1A is an oncogene and in RMS patients, high expression in tumors is associated with poor outcome. We found that p21 expression in combination with SNAI2 can predict resistance to radiation across RMS cell lines. We next developed control RD, Rh30 and Rh18 cells either CDKN1A or both CDKN1A and SNAI2 ablated using CRISPR/Cas9 reagents with control cells expressing control gRNAs. Ablation of CDKN1A while not effecting proliferation led to a significant increase in apoptosis post-radiation and this effect was increased in SNAI2/CDKN1A double knockout cells. Further, in colony forming assays we find that double ablated cells form significantly fewer colonies than control and single knockout cells. Rather unexpectedly, loss of CDKN1A, SNAI2, or CDKN1A/SNAI2 led to a G2/M cell cycle block, indicating that the cell cycle effects of p21 might not be responsible for the phenotypes observed. Ongoing xenograft experiments will determine if the effect we observe in vitro will also translate in vivo. Additionally, we are performing experiments to test how SNAI2 modulates CDKN1A expression. In summary, our study identifies CDKN1A as an oncogene that protects SNAI2 deficient cells from ionizing radiation, thus enabling the survival or rare relapse driving tumor cells. Citation Format: Paulomi S. Modi, Long Wang, Prethish Sreenivas, Myron Ignatius. A SNAI2/CDKN1A pathway protects rhabdomyosarcoma tumors from radiation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1465.

Quantitative proteomics identifies and validates urinary biomarkers of rhabdomyosarcoma in children

BackgroundRhabdomyosarcoma (RMS) is the most common soft tissue sarcoma with poor prognosis in children. The 5-year survival rate for early RMS has improved, whereas it remains unsatisfactory for advanced patients. Urine can rapidly reflect changes in the body and identify low-abundance proteins. Early screening of tumor markers through urine in RMS allows for earlier treatment, which is associated with better outcomes.MethodsRMS patients under 18 years old, including those newly diagnosed and after surgery, were enrolled. Urine samples were collected at the time points of admission and after four cycles of chemotherapy during follow-up. Then, a two-stage workflow was established. (1) In the discovery stage, differential proteins (DPs) were initially identified in 43 RMS patients and 12 healthy controls (HCs) using a data-independent acquisition method. (2) In the verification stage, DPs were further verified as biomarkers in 54 RMS patients and 25 HCs using parallel reaction monitoring analysis. Furthermore, a receiver operating characteristic (ROC) curve was used to construct the protein panels for the diagnosis of RMS. Gene Ontology (GO) and Ingenuity Pathway Analysis (IPA) software were used to perform bioinformatics analysis.ResultsA total of 251 proteins were significantly altered in the discovery stage, most of which were enriched in the head, neck and urogenital tract, consistent with the most common sites of RMS. The most overrepresented biological processes from GO analysis included immunity, inflammation, tumor invasion and neuronal damage. Pathways engaging the identified proteins revealed 33 common pathways, including WNT/β-catenin signaling and PI3K/AKT signaling. Finally, 39 proteins were confirmed as urinary biomarkers for RMS, and a diagnostic panel composed of 5 candidate proteins (EPS8L2, SPARC, HLA-DRB1, ACAN, and CILP) was constructed for the early screening of RMS (AUC: 0.79, 95%CI = 0.66 ~ 0.92).ConclusionsThese findings provide novel biomarkers in urine that are easy to translate into clinical diagnosis of RMS and illustrate the value of global and targeted urine proteomics to identify and qualify candidate biomarkers for noninvasive molecular diagnosis.