Gamma-secretase Research Articles

Tumor volume and T2 hyperintensity changes from DeFi: A phase 3, randomized, controlled trial of nirogacestat in patients with desmoid tumors.

11514 Background: MRI tumor volume or T2 signal intensity changes may represent novel imaging techniques that could have a prognostic or predictive value for assessing response in desmoid tumors (DT). For example, hyperintense areas on T2-weighted images have been associated with active fibroblastic proliferation and ≥90% hyperintensity is associated with DT disease progression, whereas iso- or hypo-intense areas are associated with inactive sites of disease. In DeFi (NCT03785964), the novel gamma secretase inhibitor nirogacestat (n=70 patients) significantly improved the primary endpoint of PFS compared with placebo (n=72 patients; hazard ratio, 0.29 [95% CI, 0.15, 0.55; P<0.001]) and significantly improved the secondary endpoint of ORR per blinded, independent central review (41% vs 8%; P<0.001). Complete responses were achieved in 7% with nirogacestat and 0% with placebo. Here, we present an exploratory analysis of MRI tumor volume and T2 signal intensity changes in DeFi. Methods: Eligible adults had histologically confirmed DT that had progressed ≥20% per RECIST v1.1 within 12 months of screening. Patients were randomized 1:1 to receive nirogacestat 150 mg or placebo twice daily taken continuously in 28-day cycles. Volumetric MRI and T2 hyperintensity of the largest target tumor were evaluated at screening and every 6 cycles during the double-blind phase. MRI T2 signal intensity is represented as the ratio of hyperintensity in total tumor volume to muscle background. A blinded, independent, central radiologist reviewed all MRI scans. Results: Nirogacestat treatment led to more substantial reductions versus placebo in tumor volume and T2 hyperintensity ratio (Table). At baseline, similar proportions of patients in each arm had a T2 hyperintensity ratio ≥90% (95% vs 97%). This ratio changed from ≥90% at baseline to <90% at any time after baseline in 34% of patients in the nirogacestat arm and 15% of those on placebo. Conclusions: In DeFi, nirogacestat demonstrated substantial reduction of tumor volume and T2 hyperintensity of the largest target tumors by MRI compared with placebo in adults with DT. These results are consistent with the significant improvement in ORR achieved with nirogacestat. These data suggest that volumetric MRI and T2 hyperintensity might provide additional information in the evaluation of treatment response in DT. The prognostic or predictive value of these imaging techniques in DT should be further studied. Clinical trial information: NCT03785964 . [Table: see text]

Presenilin-1 (PSEN1) Mutations: Clinical Phenotypes beyond Alzheimer's Disease.

Presenilin 1 (PSEN1) is a part of the gamma secretase complex with several interacting substrates, including amyloid precursor protein (APP), Notch, adhesion proteins and beta catenin. PSEN1 has been extensively studied in neurodegeneration, and more than 300 PSEN1 mutations have been discovered to date. In addition to the classical early onset Alzheimer's disease (EOAD) phenotypes, PSEN1 mutations were discovered in several atypical AD or non-AD phenotypes, such as frontotemporal dementia (FTD), Parkinson's disease (PD), dementia with Lewy bodies (DLB) or spastic paraparesis (SP). For example, Leu113Pro, Leu226Phe, Met233Leu and an Arg352 duplication were discovered in patients with FTD, while Pro436Gln, Arg278Gln and Pro284Leu mutations were also reported in patients with motor dysfunctions. Interestingly, PSEN1 mutations may also impact non-neurodegenerative phenotypes, including PSEN1 Pro242fs, which could cause acne inversa, while Asp333Gly was reported in a family with dilated cardiomyopathy. The phenotypic diversity suggests that PSEN1 may be responsible for atypical disease phenotypes or types of disease other than AD. Taken together, neurodegenerative diseases such as AD, PD, DLB and FTD may share several common hallmarks (cognitive and motor impairment, associated with abnormal protein aggregates). These findings suggested that PSEN1 may interact with risk modifiers, which may result in alternative disease phenotypes such as DLB or FTD phenotypes, or through less-dominant amyloid pathways. Next-generation sequencing and/or biomarker analysis may be essential in clearly differentiating the possible disease phenotypes and pathways associated with non-AD phenotypes.

322 Notch-dependent and independent functions of gamma secretase alter keratinocyte-mediated inflammation and adhesion

322 Notch-dependent and independent functions of gamma secretase alter keratinocyte-mediated inflammation and adhesion

Abstract CT070: Double-blind placebo-controlled trial of AL102 for treatment of progressing desmoid tumors: the RINGSIDE phase 3 study design

Abstract Background: There is an unmet need for effective systemic therapy for desmoid tumors (DT, aggressive fibromatosis) that provides durable tolerability, symptom improvement, and tumor regression. Gamma secretase inhibitors (GSIs) demonstrate antitumor activity against DT. AL102 is a potent, orally available, selective GSI under investigation as an antineoplastic agent. Methods: RINGSIDE (AL-DES-01) is a 2-part Phase 2/3 study. In the open-label Phase 2 study (Part A), adults with progressing DT (≥10% unidimensional growth within 18 months or DT-related pain requiring non-opioid medication) were randomized to three dosing regimens: 1.2 mg once daily, 2 mg intermittent BIW (2 days on 5 days off), or 4 mg intermittent BIW. RINGSIDE Phase 3 (Part B) is a double-blind, placebo-controlled study evaluating the chosen dose regimen from Phase 2 (1.2 mg once daily) in adults and adolescents (≥12 years of age) with recurrent or treatment-naïve histologically confirmed progressing DT per investigator. For eligibility, progression is defined as ≥20% measured by MRI or CT scan according to RECIST v1.1 within 12 months of the screening visit. Planned enrollment is for ≈156 subjects globally to be randomized 1:1 to either AL102 1.2 mg once daily or placebo. Randomization will be stratified according to tumor location: intra-abdominal vs. extra-abdominal (including abdominal wall). Subjects will undergo MRI or CT scans (using the same modality throughout the study) every 12 weeks to assess tumor response according to RECIST v1.1 by blinded independent central review (BICR). The primary endpoint is progression-free survival (PFS) by BICR based on RECIST v1.1. Primary and secondary endpoints are summarized in Table 1. The trial is currently enrolling. Table 1. RINGSIDE Phase 3 Study Endpoints Objectives Endpoints Primary Evaluate effects of AL102 on disease progression PFS defined as time from randomization until date of assessment of progression (assessed by BICR based on RECIST v1.1) or death by any cause Secondary Evaluate additional effects of AL102 on tumor response • ORR (CR and PR) by BICR based on RECIST v1.1 • DOR defined by time from CR or PR (by BICR based on RECIST v1.1) until first documentation of disease progression or death from any cause Evaluate effects of AL102 on quality of life • Change from baseline in quality of life as determined by: • GOunder/Desmoid Tumor Research Foundation (DTRF) DEsmoid Symptom Scale and Impact Scale (GODDESS) • Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function • EuroQol 5-Dimensional (EQ-5D-3L) questionnaire • Patient’s Global Impression of Change (PGI-C) • Change from baseline in pain assessment using Brief Pain Inventory (BPI) short form Evaluate safety and tolerability of AL102 • Frequency, duration and severity of treatment-emergent adverse events (TEAEs) and serious AEs • Time to treatment discontinuation due to TEAE BICR: blinded independent central review; CR: complete response; DOR: duration of response; ORR: objective response rate; PR: partial response; PFS: progression-free survival; RECIST: Response Evaluation Criteria in Solid Tumors Citation Format: Mrinal Gounder, Robin L. Jones, Jonathan Yovell, Gary Gordon, Bernd Kasper. Double-blind placebo-controlled trial of AL102 for treatment of progressing desmoid tumors: the RINGSIDE phase 3 study design [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT070.

Amyloid-beta aggregation implicates multiple pathways in Alzheimer's disease: Understanding the mechanisms.

Alzheimer's disease (AD) is a progressive neurodegenerative condition characterized by tau pathology and accumulations of neurofibrillary tangles (NFTs) along with amyloid-beta (Aβ). It has been associated with neuronal damage, synaptic dysfunction, and cognitive deficits. The current review explained the molecular mechanisms behind the implications of Aβ aggregation in AD via multiple events. Beta (β) and gamma (γ) secretases hydrolyzed amyloid precursor protein (APP) to produce Aβ, which then clumps together to form Aβ fibrils. The fibrils increase oxidative stress, inflammatory cascade, and caspase activation to cause hyperphosphorylation of tau protein into neurofibrillary tangles (NFTs), which ultimately lead to neuronal damage. Acetylcholine (Ach) degradation is accelerated by upstream regulation of the acetylcholinesterase (AChE) enzyme, which leads to a deficiency in neurotransmitters and cognitive impairment. There are presently no efficient or disease-modifying medications for AD. It is necessary to advance AD research to suggest novel compounds for treatment and prevention. Prospectively, it might be reasonable to conduct clinical trials with unclean medicines that have a range of effects, including anti-amyloid and anti-tau, neurotransmitter modulation, anti-neuroinflammatory, neuroprotective, and cognitive enhancement.

Gamma secretase inhibition: Effects on fertility and embryo-fetal development in rats

Avagacestat inhibits γ-secretase, a protease that cleaves the amyloid precursor protein (APP) to produce amyloid beta (Aβ). Aβ plaques, a predominant lesion in Alzheimer's patient's brain, is considered a mechanism driving neurodegeneration. As part of the nonclinical reproductive safety assessment, avagacestat effects on fertility and early embryonic development and embryo-fetal development were evaluated in rats. In the embryo-fetal development study, avagacestat was a selective developmental toxicant with dose-related increased fetal mortality, decreased fetal growth, and increased fetal malformations and variations (primarily affecting the axial and appendicular skeletal system) at ≥3 mg/kg/day. In the female fertility and early embryonic development study, avagacestat-related reductions in female fecundity at ≥5 mg/kg/day were attributed to impaired ovarian follicular development that was reflected in dose-dependent reductions in implantation sites, litter size, and gravid uterine weights. In the male fertility and early embryonic development study, avagacestat-related effects on reproduction could not be fully assessed because of low systemic exposures achieved due to extensive metabolism and clearance of the drug. The results obtained in these studies were consistent with pharmacologically mediated inhibition of γ-secretase and resulting inhibition of Notch processing and signaling that are key for embryonic development and ovary folliculogenesis. These findings are not considered a risk for late-onset AD where the patient population is ≥65 years old most with women who are post-menopausal. However, for treatment of early onset AD with a younger patient population, there are risks for reproductive or developmental toxicities with treatment with gamma secretase inhibitors like avagacestat.

Abstract 3928: Therapeutic targeting of NOTCH1 and neddylation pathway in T cell acute lymphoblastic leukemia

Abstract T-cell Acute Lymphoblastic Leukemia (T-ALL) is hematologic tumor characterized by the diffuse infiltration of the bone marrow by malignant hematopoietic cells expressing immature T cell markers. Although T-ALL currently has better cure rates primarily due to multiagent or intensified chemotherapy, the prognosis for patients who are resistant or develop relapse to therapy remains very poor. Aberrant Notch homolog-1 (NOTCH1) signaling is a major driver of T-ALL pathogenesis as more than 60% of T-ALL cases harbor activating mutations in the NOTCH1 gene. Gamma Secretase Inhibitors (GSIs) which effectively block the activation of oncogenic protein NOTCH1 are potential candidates for the treatment of T-ALL. However, the clinical application of GSIs is hampered by severe gastrointestinal toxicity due to the inhibition of NOTCH1 signaling in the gut. Here we demonstrate that combination therapy of GSIs and a small molecule inhibitor of the neddylation pathway circumvents the GSI-induced gut toxicity in vitro and in vivo. Genome-wide CRISPR loss-of-function screen in LS174T adenocarcinoma cells revealed neddylation pathway as a main regulator of massive goblet cell differentiation upon NOTCH1 inhibition. Genetic and pharmacologic inhibition of the neddylation pathway in LS174T cells rescued GSI-induced differentiation and cell death. Mechanistically, neddylation inhibition increases the protein stability of Hairy and enhancer of split-1 (HES1), a known regulator of absorptive and secretory cell fate decisions. Combination treatment of GSI and neddylation inhibitor in C57/BL6 mice showed a profound decrease in the number of goblet cells and maintained HES1 protein levels in the intestinal epithelium compared to GSI treatment alone. Remarkably, combined treatment of GSI and neddylation inhibitor in NOTCH1-induced T-ALL mice showed leukemia regression and improved overall survival without any associated gut toxicity. Overall, these results substantiate the potential of targeting NOTCH1 and neddylation pathway in the treatment of NOTCH1-induced T-ALL. Citation Format: Carla Bertulfo, Pablo Perez-Duran, Teresa Palomero, Adolfo Ferrando. Therapeutic targeting of NOTCH1 and neddylation pathway in T cell acute lymphoblastic leukemia. [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 3928.

Homotaurine and Curcumin Analogues as Potential Anti-Amyloidogenic Agents

Currently, there is neither a cure for Alzheimer’s disease (AD) nor a way to stop the progressive death of neuronal cells associated with this devastating aliment. To date, there are only medications that temporarily slow its progression, and do not interfere with its pathogenesis. One of the hallmarks of AD is the presence of amyloid-beta plaques derived from the metabolism of the amyloid precursor protein, via the cleavage by beta followed by gamma secretase. Homotaurine, a naturally occurring small molecule found in some seaweeds, and curcumin, a phenolic antioxidant found in Curcuma longa, have been extensively studied as potential compounds to prevent/reverse plaque formation. In this study, libraries of chalcones and extended chalcones based on curcumin, as well as aminopropylsulfonamides inspired by homotaurine, were synthesized. Using fluorescence spectroscopic analysis with Thioflavin T, the anti-aggregation effect on Aβ42 was determined. A select number of newly synthesized chalcones and extended chalcone analogs were revealed to be potential anti-amyloidogenic agents. These were further evaluated with regard to their neurotoxicity/neuroprotection. The extended chalcone analogs that displayed the most anti-aggregation effect on Aβ42 were further analyzed in an MTT assay. Although none of the compounds alone displayed any neurotoxicity, none were able to provide neuroprotection against Aβ42.

NEPHROPROTECTIVE EFFECT OF GAMMA-SECRETASE INHIBITOR ON SEPSIS- INDUCED RENAL INJURY IN MOUSE MODEL OF CLP.

The aim: This study was set out to assess the potential protective impact of MK0752 (a gamma secretase inhibitor) on sepsis-induced renal injury through modulation of inflammatory and oxidative stress pathways. Materials and methods: Twenty-four Swiss-albino mice aged between eight and twelve week and weighted twenty to thirty-seven grams were randomly allocated into four groups (n=6 in each group). Sham group (laparotomy without cecal ligation and puncture (CLP), sepsis group (laparotomy with CLP), vehicle-treated group (equivalent volume of DMSO before the CLP), MK0752 treated group (5 mg/kg) single daily dose for three days before the CLP. Blood samples were used to assess the serum levels of urea and creatinine. The kidneys were used to assess tissue levels of the TNF-α, IL-10, IL-6, TNFR1, VEGF, notch1, jagged1 and tissue damage by histopathological analysis. Results: The current study shows that pretreatment with MK0752 ameliorates the renal damage by significantly reducing the proinflammatory cytokines and notch1 signaling. Conclusions: Taken together, these results suggest that MK0752 could be protective against the renal injury induced by sepsis through its ameliorative impact on renal architecture and modulating cytokines and Notch1 singling pathway. Further studies regarding the role of Notch signaling pathways would be worthwhile.

In silico identification of potential γ-secretase inhibitor of marine-algal origin: an anticancer intervention

ABSTRACT Gamma secretase (GS) activates notch signalling pathway (NSP) by liberating the truncated notch intracellular domain (NICD). The NSP is associated with the cancer development and progression, which makes GS a potential therapeutic target. Now day’s marine compounds emerged as a major source of bioactive entity. The NSP inhibition potential of marine-algal compounds has not yet been studied. Thus, in the present study, we have used molecular docking, molecular dynamics (MD) simulations, principal component analysis (PCA) and free energy and binding energy calculations to identify the potential GS inhibitors of marine-algal origin. Laminarin showed better docking score (−12.72) compared to the known GS inhibitor DAPT (−9.2). Laminarin formed H-Bond interaction with the Asp257 and Asp385 required for the catalytic cleavage activity of gamma-secretase. It potentially stabilised the structural parameters (RMSD, RMSF, Rg and SASA) of GS catalytic subunit compared to DAPT during the MD simulation. The PCA and free energy calculation revealed conformationally and energetically stable Laminarin–GS complex formation. Laminarin showed lower binding energy (−44.75 kcal/mol) with GS catalytic subunit than DAPT (−20.92 kcal/mol). In conclusion, the present study provides a marine-algal compound as a novel potential GS inhibitor, which requires further validation in experimental model.

Pharmacodynamic Effects of Nirogacestat, a Gamma Secretase Inhibitor, on B-Cell Maturation Antigen in Healthy Participants

Purpose: B-cell maturation antigen (BCMA) is expressed on the cell membrane of normal plasma cells (PCs) and multiple myeloma (MM) cells and is the target of several investigational agents and approved products for the treatment of MM. Low BCMA receptor density may be associated with lower response rates, less durable responses, or resistance to BCMA therapies. Mechanistically, BCMA is cleaved from the cell surface by the enzyme gamma secretase (GS), which results in reduced levels of membrane bound BCMA (mbBCMA) and generation of soluble BCMA (sBCMA). GS inhibitors (GSIs) have been shown to increase mbBCMA, and potentiation of the activity of several BCMA-targeted therapies has been demonstrated in vitro and in clinical studies in combination with GSIs. While the effect of GS inhibition on mbBCMA has been reproducibly characterized in vitro, the effect on BCMA dynamics has yet to be adequately characterized in humans. Therefore, this study sought to evaluate the pharmacodynamics of the GSI nirogacestat on mbBCMA on PCs in healthy participants. Methods: An adaptive design clinical study in healthy participants used quantitative flow cytometry to evaluate mbBCMA receptor density on PCs collected from bone marrow (BM) and whole blood (WB) following administration of nirogacestat. In the first cohort, 9 participants received a single dose of nirogacestat 150 mg, and mbBCMA density on PCs isolated from BM and WB was measured at baseline and 4, 8, 24, or 48 hours post-dose. Changes in the percentage of mbBCMA+ PCs, serum concentrations of sBCMA, and serum concentrations of nirogacestat were also determined. Based on the results of the first cohort, participants were enrolled in a second cohort in which different dose levels, treatment schedules, and post-dose collection time points were included to refine the exposure-response relationship and to better understand the dynamics of mbBCMA. Results: Nirogacestat dosing in healthy participants resulted in a rapid increase in mbBCMA density on PCs isolated from BM and WB. Maximal increases in mbBCMA (8- to 12-fold) were observed from 4 to 8 hours post-dose and returned to baseline levels by 24 to 48 hours. These changes in mbBCMA density correlated with serum concentrations of nirogacestat. The responses in BM and WB were generally similar, but there were some differences in mbBCMA dynamics. The serum nirogacestat concentrations and mbBCMA density values were used to develop a pharmacokinetic/pharmacodynamic (PK/PD) model that describes mbBCMA dynamics relative to GSI concentrations, including receptor density on PCs in both BM and WB. Results of the final PK/PD model will be presented. Conclusions: Administration of a single dose of nirogacestat in healthy participants resulted in a robust but temporary increase in mbBCMA receptor density on PCs in both BM and WB that correlated with nirogacestat serum concentrations, indicating that the turnover of mbBCMA on PCs is rapid and its abundance on the cell surface is directly regulated by GS activity. PK/PD modeling showed that sustained serum concentrations of nirogacestat are necessary for maintaining elevated levels of mbBCMA receptor density, thereby suggesting that the schedule of nirogacestat dosing may have direct implications on the potentiation of BCMA-targeting therapies. This PK/PD study supports the use of nirogacestat to increase mbBCMA levels on myeloma cells in patients receiving BCMA-directed therapy. Ongoing and planned studies are evaluating mbBCMA dynamics with nirogacestat combined with BCMA-targeted treatments in patients with MM.

Amyloid Beta in Aging and Alzheimer's Disease.

Alzheimer's disease (AD), is a progressive neurodegenerative disease that affects behavior, thinking, learning, and memory in elderly individuals. AD occurs in two forms, early onset familial and late-onset sporadic; genetic mutations in PS1, PS2, and APP genes cause early onset familial AD, and a combination of lifestyle, environment and genetic factors causes the late-onset sporadic form of the disease. However, accelerated disease progression is noticed in patients with familial AD. Disease-causing pathological changes are synaptic damage, and mitochondrial structural and functional changes, in addition to increased production and accumulation of phosphorylated tau (p-tau), and amyloid beta (Aβ) in the affected brain regions in AD patients. Aβ is a peptide derived from amyloid precursor protein (APP) by proteolytic cleavage of beta and gamma secretases. APP is a glycoprotein that plays a significant role in maintaining neuronal homeostasis like signaling, neuronal development, and intracellular transport. Aβ is reported to have both protective and toxic effects in neurons. The purpose of our article is to summarize recent developments of Aβ and its association with synapses, mitochondria, microglia, astrocytes, and its interaction with p-tau. Our article also covers the therapeutic strategies that reduce Aβ toxicities in disease progression and discusses the reasons for the failures of Aβ therapeutics.

Antibody drug conjugates for the treatment of multiple myeloma.

The treatment landscape of multiple myeloma (MM) has evolved substantially, but it remains largely incurable so new treatment options are required. Antibody drug conjugates (ADCs) are an emerging therapeutic class used in Cancer to deliver targeted therapy. ADCs are composed of three components, an antibody, a chemical linker and a payload which must be chosen carefully to be effective and safe. This alternative mechanism of action to standard treatments makes ADCs an attractive class for further development. However, several ADCs have been investigated but many have not moved further than phase 1 trials, highlighting the challenges in designing an effective and tolerable ADC. Belantamab Mafodotin is currently the only ADC licensed for MM although others are currently under evaluation. Belantamab Mafodotin demonstrated efficacy as monotherapy in triple class exposed patients and combinations are under development which maintain safety with encouraging efficacy particularly at earlier lines of therapy. Retaining an acceptable adverse event profile for ADCs remains vital for their success. Strategies to mitigate ocular events for Belantamab Mafodotin involve lower and less frequent dosing as well as the use of gamma secretase inhibitors. The optimal sequencing of ADCs within the treatment pathway including novel immunotherapies is now under evaluation.

Hesperidin potentially interacts with the catalytic site of gamma-secretase and modifies notch sensitive genes and cancer stemness marker expression in colon cancer cells and colonosphere

Gamma secretase (GS) produces Notch Intracellular Domain (NICD) by trans-membrane cleavage of notch receptor. The NICD enters the nucleus and activates the notch signaling pathway (NSP) by activating notch-responsive gene transcription. Hyperactivation of NSP is related to cancer aggressiveness, therapy resistance, and poor therapy outcome, and decreased overall disease-free survival in patients. Till date, none of the GS inhibitors (GSI) has been clinically approved due to their toxicity in patients. Thus in the present study, we explored the GS catalytic site binding potential of hesperidin (natural flavone glycoside) and its effect on notch responsive gene expression in HCT-116 cells. Molecular docking, MM-GBSA binding energy calculations, and molecular dynamics (MD) simulation experiments were performed to study the GS catalytic site binding potential of hesperidin. The compound showed better GS catalytic site binding potential at the active site compared to experimentally validated GSI, N-N-(3, 5-Difluorophenacetyl)-L-alanyl-S-phenylglycine t-butyl ester (DAPT) in molecular docking and MM-GBSA experiments. MD simulation results showed that hesperidin forms stable and energetically favorable complex with gamma secretase in comparison to standard inhibitor (DAPT)-GS complex. Further, in vitro experiments showed that hesperidin inhibited cell growth and sphere formation potential in HCT-116 cells. Further, hesperidin treatment altered notch responsive genes (Hes1, Hey1, and E-cad) and cancer stemness/self-renewal markers expression at transcription levels. In conclusion, hesperidin produces toxicity in HCT-116 cells and decreases colonosphere formation by inhibiting transcription of notch signaling pathway target genes and stemness markers. Communicated by Ramaswamy H. Sarma

Rutin Potentially Binds the Gamma Secretase Catalytic Site, Down Regulates the Notch Signaling Pathway and Reduces Sphere Formation in Colonospheres.

Rutin, a natural flavonol, can modulate molecular signaling pathways and has considerable potential in cancer treatment. However, little is known about the effect of rutin on the notch signaling pathway (NSP) in cancer and cancer stem-like cells. In this study, we explored the effect of rutin on gamma secretase (GS, a putative notch signaling target) inhibition mediated NICD (Notch Intracellular Domain) production in colon cancer cells. Molecular docking, MM-GBSA, and Molecular dynamics (MD) simulation experiments were performed to check rutin’s GS catalytic site binding potential. The HCT-116 colon cancer and cancer stem-like cells (colonospheres) were utilized to validate the in silico findings. The NICD production, notch promoter assay, expression of notch target genes, and cancer stemness/self-renewal markers were studied at molecular levels. The results were compared with the Notch-1 siRNA transfected test cells. The in silico study revealed GS catalytic site binding potential in rutin. The in vitro results showed a decreased NICD formation, an altered notch target gene (E-cad, Hes-1, and Hey-1) expression, and a reduction in stemness/self-renewal markers (CD44, c-Myc, Nanog, and Sox2) in test cells in a time and dose-dependent manner. In conclusion, rutin inhibits the notch signaling pathway and reduces the stemness/self-renewal property in colon cancer cells and the colonospheres by targeting gamma secretase. The clinical efficacy of rutin in combination therapy in colon cancer may be studied in the future.

1488MO Initial results of phase II/III trial of AL102 for treatment of desmoid tumors (DT)

AL102 is a potent, orally available, selective gamma secretase inhibitor (GSI) under investigation as an antineoplastic agent. GSIs have antitumor activity against DT, including AL101 (2 confirmed PRs >3.5 years and >1 year; 1 stable disease for 1 year). There remains an unmet need for effective systemic therapy in DT, associated with durable tolerability, tumor regression, and symptom improvement.

LBA2 DeFi: A phase III, randomized controlled trial of nirogacestat versus placebo for progressing desmoid tumors (DT)

DT are rare, locally aggressive soft-tissue tumors without approved systemic therapy. Nirogacestat (niro), a novel oral gamma secretase inhibitor (GSI) has shown antitumor activity in patients with DT.

Gamma secretase inhibitors as potential therapeutic targets for the notch signaling pathway in uterine leiomyosarcoma (199)

Gamma secretase inhibitors as potential therapeutic targets for the notch signaling pathway in uterine leiomyosarcoma (199)

The Role of Pharmacotherapeutic Agents in Children with Desmoid Tumors.

Desmoid tumors (DT) are rare fibroblastic, soft-tissue tumors that do not metastasize but can aggressively infiltrate tissues causing significant chronic discomfort and/or functional impairment. In the pediatric population, the incidence of DT is greatest during infancy and adolescence but can occur at any age. Dysregulated β-catenin, most commonly resulting from mutations in either CTNNB1 or germline APC (adenomatous polyposis coli) drives DT. Most cases are sporadic but some are associated with predisposition syndromes such as familial adenomatous polyposis (FAP). Historically, treatment has been surgery. However, the recurrence rate after surgery can be high. Various systemic cytotoxic chemotherapy regimens used in other soft-tissue sarcomas have been applied to DT with differing results. Given the chronic and rarely life-threatening nature of this disease and the potential short- and long-term toxicity of these regimens, especially in children, alternative non-cytotoxic interventions have been investigated. Molecularly targeted agents such as tyrosine kinase and gamma secretase inhibitors have shown activity against DT. Innovative local control therapies are being employed as alternatives to surgery and radiation. Periods of prolonged stability and spontaneous regression in the absence of therapy in some patients has prompted wider adoption of an upfront active surveillance approach in the appropriate setting. This review will briefly summarize the epidemiology, pathophysiology, and clinical presentation of DT in children, then focus on historical, current, and future pharmacotherapeutic management and finally, propose areas for future study.

Abstract 6074: Resistance to MK-0752 alters Notch activity and expression of stemness markers in uterine leiomyosarcoma cell lines

Abstract Introduction: Uterine leiomyosarcoma (uLMS) is a rare tumor with poor survival and few therapeutic options. The Notch pathway is evolutionarily conserved, is active in uterine processes, has oncogenic properties in many cancers, but has not been well studied in uLMS. Cancer stem cells (CSC) are subpopulations of cancer cells that are treatment resistant. In certain tumors, activation of canonical Notch signaling, via gamma secretase, supports CSC survival and the acquisition of chemoresistance. Our objective is to identify and characterize the subpopulation of uLMS cells that are viable after treatment with the half maximal inhibitory concentration (IC50) of MK-0752, a gamma secretase inhibitor (GSI) in phase I trials. We will determine Notch signaling activity and expression of markers associated with stem-like potential in GSI resistant uLMS cells. Methods: MTT assays were performed on SK-LMS-1 and SK-UT-1B, two uLMS cell lines, to identify the IC50 for MK-0752. Cells were exposed to MK-0752 at the IC50 or DMSO (control) for 24 hours and viable cells were collected. First, expression of stemness markers, CD133, cMYC and SOX2, in uLMS cells was compared to human uterine smooth muscle cells (hUT-SMC) at baseline. After treatment with MK-0752, the remaining subpopulations of resistant uLMS cells were evaluated for Notch signaling activity by expression of HES1. Stemness marker expression was also assessed. Gene expression was measured with qRT-PCR. Mean fold change (FC) gene expression was determined by FC experimental divided by FC control, relative to expression of 18S rRNA. P≤0.05 was considered significant. Results: In untreated uLMS cells, expression of CD133 and c-MYC was significantly higher in SK-LMS-1 (fibroblast morphology) vs hUT-SMC, while expression of CD133 and SOX2 was significantly higher in SK-UT-1B (epithelial morphology) vs hUT-SMC. After treatment with MK-0752 at IC50 (427.4 µM for SK-LMS-1 or 128.4µM for SK-UT-1B) expression of HES1 was decreased in SK-LMS-1 (0.35x, p≤0.05) and increased in SK-UT-1B (2.38x, p≤0.01) in treatment resistant, viable cells as compared to untreated cells. Expression of c-MYC was decreased (0.38x, p≤0.01) and CD133 was similar (1.64x, p>0.05) in GSI resistant SK-LMS-1 cells, while expression of CD133 and SOX2 was similar (1.43x and 1.30x, respectively, p>0.05) in GSI resistant SK-UT-1B cells compared to untreated cells. Conclusions: Cellular morphology, Notch signaling activity and expression of stemness markers differs in GSI resistant SK-LMS-1 compared to GSI resistant SK-UT-1B cells. The subpopulation of MK-0752 resistant SK-LMS-1 cells have reduced Notch activity and reduced expression of stemness marker, c-MYC, while the resistant SK-UT-1B cells have increased Notch activity. Further studies are required to identify additional factors associated with uLMS resistance to GSIs and the importance of this heterogeneity of uLMS in vivo. Citation Format: Yasmin Abedin, Emily Alpert, Erica Rego, Karla Larios, Emma Cheung, Sofia Gabrilovich, Qingshi Zhao, Mark H. Einstein, Nataki Douglas. Resistance to MK-0752 alters Notch activity and expression of stemness markers in uterine leiomyosarcoma cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6074.