Inhibition Of Cholesterol Biosynthesis Research Articles

Abstract PO4-13-10: The anti-metastatic role of BMP4 through cholesterol biosynthesis inhibition and consequent interaction with statin benefit in breast cancer

Abstract We have previously identified a role for bone morphogenic protein 4 (BMP4) in reducing distant relapse risk after early breast cancer (BrCa) (1). We therefore set out to identify mechanisms underlying the protective effect of BMP4, looking to translate this finding for patient benefit. A highly metastatic variant of the triple negative MDA-MB-231 human BrCa line (231-HM-turboGFP) was transduced with BMP4, leading to sustained BMP4 secretion. These modified tumours were established in NSG mice, resected at a given size and turboGFP-positive cancer cells were recovered from primary tumours for RNA sequencing analysis. Gene set enrichment analysis (GSEA) was completed to identify signalling pathways that were significantly modulated by BMP4. The four most significantly downregulated gene sets were associated with cholesterol synthesis, with the overwhelming majority of genes in this pathway being downregulated. BMP4 downregulation of 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1, involved in cholesterol biosynthesis) was confirmed at the protein level by western blotting on whole tumour lysates. Forced expression of BMP4 also led to a significant reduction in the levels of free and total cholesterol. In a confirmatory analysis of the METABRIC human BrCa dataset, the expression of cholesterol biosynthesis-related genes inversely correlated with the expression of BMP4. Further, for the majority of these genes, expression was elevated in high-grade breast tumours, and predicted worse overall survival of patients. Finally, we tested the effect of a lipophilic statin, lovastatin, on the growth and metastasis of 231-HM-turboGFP tumours. Treatment did not affect the growth of primary tumours but significantly less metastases were observed in the lungs of treated mice, at least partially replicating the anti-metastatic effect of BMP4. Having identified inhibition of cholesterol biosynthesis as a potential mechanism of protective BMP4 action we then asked if BMP4 status interacted with any protective effect of co-administered statins. We therefore returned to the cohort initially employed to demonstrate BMP4 benefit (1) and looked at the interaction between BMP4 protein levels and statin usage with regards to recurrence. BMP4 protein and statin usage data were available on a cohort of 417 patients with early BrCa. Statin use compared to none led to a reduced risk of distant relapse (8 v 22%, 0.0029) at 15 years. BMP4 led to borderline reduction in distant relapse (16 v 24%, p=0.052). In BMP4 negative tumours, statin protected against any relapse (p=0.0025) whereas in BMP4 positive disease no significant risk reduction was not significant (p=0.074). Absence of BMP4 expression may be a biomarker of both higher relapse risk and statin benefit in early BrCa. 1. Eckhardt et al, Cancer Res. 2020;80(6):1304-1315 Citation Format: Lap Hing Chi, Andrew Redfern, Allan Burrows, Suraya Roslan, Leone Oh, Lisa Spalding, Robin Anderson. The anti-metastatic role of BMP4 through cholesterol biosynthesis inhibition and consequent interaction with statin benefit in breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-13-10.

Exploring the Hypocholesterolemic Potential of a Fucus vesiculosus Extract: Omic Insights into Molecular Mechanisms at the Intestinal Level.

High blood cholesterol levels are a major risk factor for cardiovascular diseases. A purified aqueous extract of Fucus vesiculosus, rich in phlorotannins and peptides, has been described for its potential to inhibit cholesterol biosynthesis and intestinal absorption. In this work, the effect of this extract on intestinal cells' metabolites and proteins was analysed to gain a deeper understanding of its mode of action on lipids' metabolism, particularly concerning the absorption and transport of exogenous cholesterol. Caco-2 cells, differentiated into enterocytes, were exposed to the extract, and analysed by untargeted metabolomics and proteomics. The results of the metabolomic analysis showed statistically significant differences in glutathione content of cells exposed to the extract compared to control cells, along with an increased expression of fatty acid amides in exposed cells. A proteomic analysis showed an increased expression in cells exposed to the extract compared to control cells of FAB1 and NPC1, proteins known to be involved in lipid metabolism and transport. To the extent of our knowledge, this study is the first use of untargeted metabolomics and a proteomic analysis to investigate the effects of F. vesiculosus on differentiated Caco-2 cells, offering insights into the molecular mechanism of the extract's compounds on intestinal cells.

Abstract 4126: The inhibitory effect of statins on distant metastasis and recurrence of endometrial cancer

Abstract Endometrial cancer (EC) is the most common gynecologic malignancy. The most common histological type is endometrioid endometrial cancer (EEC). While the majority of patients present with early-stage and low-grade EEC and have an excellent prognosis, a subset develops distant recurrence derived from EEC after initial treatment of the primary. However, the exact mechanism of distant metastasis and recurrence from EEC is still unclear. In addition, the lack of suitable pre-clinical models is a significant barrier to research for distant metastasis and recurrent cancer derived from EEC. Our preclinical EEC model, the ablation of both Mig-6 and Pten in the uterus (Pgrcre/+Mig-6f/fPtenf/f; Mig-6d/dPtend/d), dramatically accelerates the development of EEC compared to single ablation of either gene. The ablation of both Mig-6 and Pten in the uterus (Pgrcre/+Mig-6f/f Ptenf/f; Mig-6d/dPtend/d mice) displayed distant metastases into the ovary, diaphragmatic skeletal muscle, lymph node, and lung. However, the Ptend/d mice exhibited endometrial cancer without distant metastases. After hysterectomy of EEC confined to uterus, Mig-6d/dPtend/d mice exhibited recurrent EEC in abdomen and lung. To identify prognostic factors for distant metastatic and recurrent EEC, we performed transcriptomic analysis in endometrial hyperplasia, a precancerous condition, from Ptend/d and Mig-6d/dPtend/d mice. Our transcriptomic analysis identified that cholesterol biosynthesis was the most significantly activated pathway in Mig-6d/dPtend/d mice compared to Ptend/d mice. Statins, also known as HMG-CoA reductase inhibitors, are the most common cholesterol-lowering drugs. We evaluated the effect of atorvastatin on tumorigenesis and recurrence of EEC. Mig-6d/dPtend/d mice treated with atorvastatin displayed significant reduction of tumor size compared to vehicle treated group. For vehicle-treated group, our pathological analysis revealed EEC outside the uterus, therefore EEC had disseminated to involve the ovary, diaphragmatic skeletal muscle, lymph node, and lung. However, EEC was confined to the uterus in the atorvastatin treated group. Furthermore, atorvastatin treatment reduced the rate of recurrent EEC development. This data demonstrated that atorvastatin has a remarkable inhibitory effect on metastasis and recurrence of EEC in Mig-6d/d Ptend/d mice. Our results suggest that statins suppress development of distant metastasis and recurrence in mouse models of EEC with Pten and Mig-6 deficiency by inhibiting cholesterol biosynthesis. Citation Format: Keun Cheon Kim, Jung Yoon Yoo, Russell R Broaddus, Eunhee M Jeong, Mark I Hunter, Tae Hoon Kim, Jae-Wook Jeong. The inhibitory effect of statins on distant metastasis and recurrence of endometrial cancer [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 4126.

Fluvastatin Converts Human Macrophages into Foam Cells with Increased Inflammatory Response to Inactivated Mycobacterium tuberculosis H37Ra.

Cholesterol biosynthesis inhibitors (statins) protect hypercholesterolemic patients against developing active tuberculosis, suggesting that these drugs could help the host to control the pathogen at the initial stages of the disease. This work studies the effect of fluvastatin on the early response of healthy peripheral blood mononuclear cells (PBMCs) to inactivated Mycobacterium tuberculosis (Mtb) H37Ra. We found that in fluvastatin-treated PBMCs, most monocytes/macrophages became foamy cells that overproduced NLRP3 inflammasome components in the absence of immune stimulation, evidencing important cholesterol metabolism/immunity connections. When both fluvastatin-treated and untreated PBMCs were exposed to Mtb H37Ra, a small subset of macrophages captured large amounts of bacilli and died, concentrating the bacteria in necrotic areas. In fluvastatin-untreated cultures, most of the remaining macrophages became epithelioid cells that isolated these areas of cell death in granulomatous structures that barely produced IFNγ. By contrast, in fluvastatin-treated cultures, foamy macrophages surrounded the accumulated bacteria, degraded them, markedly activated caspase-1 and elicited a potent IFNγ/cytotoxic response. In rabbits immunized with the same bacteria, fluvastatin increased the tuberculin test response. We conclude that statins may enhance macrophage efficacy to control Mtb, with the help of adaptive immunity, offering a promising tool in the design of alternative therapies to fight tuberculosis.

Oleic acid triggers metabolic rewiring of T cells poising them for T helper 9 differentiation

T cells are the most common immune cells in atherosclerotic plaques, and the function of Tcells can be altered by fatty acids. Here, we show that pre-exposure of CD4+ Tcells to oleic acid, an abundant fatty acid linked to cardiovascular events, upregulates core metabolic pathways and promotes differentiation into interleukin-9 (IL-9)-producing cells upon activation. RNA sequencing of non-activated Tcells reveals that oleic acid upregulates genes encoding key enzymes responsible for cholesterol and fatty acid biosynthesis. Transcription footprint analysis links these expression changes to the differentiation toward TH9 cells, a pro-atherogenic subset. Spectral flow cytometry shows that pre-exposure to oleic acid results in a skew toward IL-9+-producing Tcells upon activation. Importantly, pharmacological inhibition of either cholesterol or fatty acid biosynthesis abolishes this effect, suggesting a beneficial role for statins beyond cholesterol lowering. Taken together, oleic acid may affect inflammatory diseases like atherosclerosis by rewiring Tcell metabolism.

CSF1R inhibition reprograms tumor-associated macrophages to potentiate anti-PD-1 therapy efficacy against colorectal cancer

PD-1 blockade therapy has made great breakthroughs in treatment of multiple solid tumors. However, patients with microsatellite-stable (MSS) colorectal cancer (CRC) respond poorly to anti-PD-1 immunotherapy. Although CRC patients with microstatellite instability (MSI) or microsatellite instability-high (MSI-H) can benefit from PD-1 blockade therapy, there are still some problems such as tumor recurrence. Tumor-associated macrophages (TAMs), most abundant immune components in tumor microenvironment (TME), largely limit the therapeutic efficacy of anti-PD-1 against CRC. The CSF1/CSF1R pathway plays a key role in regulating macrophage polarization, and blocking CSF1R signaling transduction may be a potential strategy to effectively reprogram macrophages and remodel TME. Here, we found that increasing expression of CSF1R in macrophages predicted poor prognosis in CRC cohort. Furthermore, we discovered a novel potent CSF1R inhibitor, PXB17, which significantly reprogramed M2 macrophages to M1 phenotype. Mechanically, PXB17 significantly blocked activation of PI3K/AKT/mTORC1 signaling, resulting in inhibition of cholesterol biosynthesis. Results from 3D co-culture system suggested that PXB17-repolarized macrophages could induce infiltration of CD8+ T lymphocytes in tumors and improve the immunosuppressive microenvironment. In vivo, PXB17 significantly halted CRC growth, with a stronger effect than PLX3397. In particular, PXB17 potently enhanced therapeutic activity of PD-1 mAb in CT-26 (MSS) model and prevented tumor recurrence in MC-38 (MSI-H) model by promoting formation of long-term memory immunity. Our study opens a new avenue for CSF1R in tumor innate and adaptive anti-tumor immunomodulatory activity and suggests that PXB17 is a promising immunotherapy molecule for enhancing the efficacy of PD-1 mAb or reducing tumor recurrence of CRC.

Low-Density Lipoprotein Cholesterol-Lowering Drugs: A Narrative Review.

The modern history of cholesterol-lowering drugs started in 1972 when Dr. Akira Endo identified an active compound (compactin) that inhibited cholesterol biosynthesis from the culture broth of blue-green mold (Penicillium citrinum Pen-51). Since 1987, statins have represented the milestone for the treatment of atherosclerotic cardiovascular disease. A new therapy for the treatment of hypercholesterolemia since the discovery of statins is ezetimibe, the first and only agent inhibiting intestinal cholesterol absorption. Ezetimibe was approved by the FDA in October 2002. A year later, the association between gain-of-function PCSK9 genetic mutations and hypercholesterolemia was reported, and this discovery opened a new era in lipid-lowering therapies. Monoclonal antibodies and small-interfering RNA approaches to reduce PCSK9 were developed and approved for clinical use in 2015 and 2022, respectively. Finally, the newly approved bempedoic acid, an oral adenosine triphosphate citrate lyase inhibitor that lowers LDL-C, is able to reduce major adverse cardiovascular events in both primary and secondary prevention. In the present narrative review, we summarize the pharmacological properties and the clinical efficacy of all these agents currently used for a tailored therapy of hypercholesterolemia in patients with atherosclerotic cardiovascular disease.

Distinctive genes and signaling pathways associated with type 2 diabetes-related periodontitis: Preliminary study.

The biological mechanisms underlying the pathogenesis of type 2 diabetes (T2DM)-related periodontitis remain unclear. This cross-sectional study evaluated the distinctive transcriptomic changes between tissues with periodontal health and with periodontitis in patients with T2DM. In this cross-sectional study, whole transcriptome sequencing was performed on gingival biopsies from non-periodontitis and periodontitis tissues from non-diabetic and diabetic patients. A differentially expressed gene (DEG) analysis and Ingenuity Pathway Analysis (IPA) assessed the genes and signaling pathways associated with T2DM-related periodontitis. Immunohistochemistry was performed to validate selected DEGs possibly involved in T2DM-related periodontitis. Four hundred and twenty and one thousand five hundred and sixty-three DEGs (fold change ≥ 2) were uniquely identified in the diseased tissues of non-diabetic and diabetic patients, respectively. The IPA predicted the activation of Phagosome Formation, Cardiac β-adrenergic, tRNA Splicing, and PI3K/AKT pathways. The IPA also predicted the inhibition of Cholesterol Biosynthesis, Adrenomedullin, and Inositol Phosphate Compounds pathways in T2DM-related periodontitis. Validation of DEGs confirmed changes in protein expression of PTPN2, PTPN13, DHCR24, PIK3R2, CALCRL, IL1RN, IL-6R and ITGA4 in diseased tissues in diabetic subjects. Thus, these preliminary findings indicate that there are specific genes and functional pathways that may be involved in the pathogenesis of T2DM-related periodontitis.

Effect of Gender on Cholesterol Levels in Type 2 Diabetes Mellitus Patients

In women aged 17-50 years, a decrease in Follicle-stimulating hormone (FSH) levels will increase the hormone estrogen which requires cholesterol, so that cholesterol becomes low through inhibition of liver cholesterol biosynthesis. The purpose of this study was to determine differences in cholesterol levels between women and men with Type 2 Diabetes Mellitus. The study design was a cross-sectional analytic observational and purposive sampling technique with inclusion criteria of HbA1c > 6.5%. As a result, the average age of the male respondents was 44 years (SD±18.4), HbA1c 8.5% (SD±2.4), and cholesterol 212 mg/dL (SD±40), the average age of females was 58 years old (SD ± 7.7, HbA1c 10.6% (SD ± 3.4), and cholesterol 181 mg/dL (SD ± 37.6). The results of the Mann- Whitney test with p = 0.038 (p <0.05) mean that there is a significant difference in cholesterol levels between men and women, which means there are differences in how the brain works between men and premenopausal women who suffer from type 2 Diabetes Mellitus Suggestions for future researchers, it is necessary to conduct research on High-sensitivity C-reactive protein (hs-CRP) and low-density lipoprotein (LDL) cholesterol in premenopausal women regarding the role of estrogen and FSH in regulating cholesterol.

PKMYT1 knockdown inhibits cholesterol biosynthesis and promotes the drug sensitivity of triple-negative breast cancer cells to atorvastatin.

Triple negative breast cancer (TNBC) as the most aggressive molecular subtype of breast cancer is characterized by high cancer cell proliferation and poor patient prognosis. Abnormal lipid metabolism contributes to the malignant process of cancers. Study observed significantly enhanced cholesterol biosynthesis in TNBC. However, the mechanisms underlying the abnormal increase of cholesterol biosynthesis in TNBC are still unclear. Hence, we identified a member of the serine/threonine protein kinase family PKMYT1 as a key driver of cholesterol synthesis in TNBC cells. Aberrantly high-expressed PKMYT1 in TNBC was indicative of unfavorable prognostic outcomes. In addition, PKMYT1 promoted sterol regulatory element-binding protein 2 (SREBP2)-mediated expression of enzymes related to cholesterol biosynthesis through activating the TNF/ TNF receptor-associated factor 1 (TRAF1)/AKT pathway. Notably, downregulation of PKMYT1 significantly inhibited the feedback upregulation of statin-mediated cholesterol biosynthesis, whereas knockdown of PKMYT1 promoted the drug sensitivity of atorvastatin in TNBC cells. Overall, our study revealed a novel function of PKMYT1 in TNBC cholesterol biosynthesis, providing a new target for targeting tumor metabolic reprogramming in the cancer.

10007-ACT-2 FIRST IN HUMAN STUDY OF DSP-0390, AN ORAL EMOPAMIL BINDING PROTEIN (EBP) INHIBITOR, IN RECURRENT HIGH-GRADE GLIOMA (HGG): PRELIMINARY RESULTS

Abstract BACKGROUND Cholesterol in the brain is derived wholly from de novo biosynthesis as the blood-brain barrier prevents uptake from the circulation. The overexpression of cholesterol synthesis genes is associated with decreased survival in glioblastoma (GBM), suggesting that gliomas may be sensitive to the inhibition of cholesterol biosynthesis. DSP-0390 is an investigational small molecule that inhibits EBP, a key enzyme in cholesterol biosynthesis. Preclinical studies demonstrated antitumor activity of DSP-0390 in orthotopic xenograft GBM models. METHODS This phase I dose escalation study aims to assess the safety, PK, PD, and preliminary antitumor activity of oral DSP-0390 monotherapy for recurrent HGG (NCT05023551). Key eligibility criteria include histologically confirmed grade III or IV glioma (WHO 2016); treatment with ≥1 prior therapy; no treatment options beyond standard of care; KPS ≥70. RESULTS As of 9 May 2023, 24 patients (37.5% women) were enrolled across 6 dose levels (20 mg QD to 240 mg QD) with a median age of 51 years (range 24-76) including 17 (70.8 %) with GBM, 3 (12.5%) with anaplastic astrocytoma and 2 (8.3%) with anaplastic oligodendroglioma. Ten patients (41.7%) had IDH mutant tumors. Four patients (16.7%) were on stable dose of corticosteroids at baseline, of which 2 were able to discontinue or dose reduce the corticosteroid while on DSP-0390. There were no reported DLTs. The most common treatment-related TEAEs included grade 1 or 2 nausea (7 patients [29.2%]) and alanine aminotransferase increased (6 patients [25.0%]). Only one grade 3 related AE (dry skin) was noted. Two patients with IDH mutant grade 3 glioma had tumor reduction and remain on DSP-0390 for ≥9 months. Dose dependent changes in PK and PD were observed. CONCLUSIONS DSP-0390 has been well tolerated to date with dose escalation ongoing. A dose response relationship was observed between PK and PD biomarkers.

Abstract C091: Liquiritigenin, an estrogen receptor beta agonist, enhances cholesterol biosynthesis inhibitor RO 48-8071-induced growth inhibition of ovarian cancer cells

Abstract Almost 25,000 new cases of epithelial ovarian cancer (EOC) are reported each year in the United States. Cancers of the ovary have poor prognosis due to late detection, drug resistance and metastasis, and have the highest mortality rate of all the known gynecological malignancies. Despite concerted efforts to develop new strategies for preventing and treating ovarian cancer, novel and more effective non-toxic therapies are urgently needed. Recent observations from our laboratory show that RO 48-8071 ([4’-[6-(Allylmethylamino)hexyloxy]-4-bromo-2’-fluorobenzophenone fumarate] [RO], a small-molecule inhibitor of the key cholesterol biosynthesis enzyme 2, 3-oxidosqualene cyclase (OSC), inhibits breast and prostate cancer cells in vitro and in vivo. Further studies showed that RO also suppresses ovarian cancer cells, both in vitro and in vivo (Cholesterol Biosynthesis Inhibitor RO 48-8071 Suppresses Growth of Epithelial Ovarian Cancer Cells in Vitro and In Vivo. Journal of Cancer Science and Clinical Therapeutics 7 (2023): 01-08.). In short term assays (24h), pharmacological doses of RO (uM) suppressed ovarian cancer cell viability. In long-term assays (7 days) the same effects were observed in response to RO in the nM range. Interestingly, RO induced the tumor-suppressor protein estrogen receptor-beta (ER-beta) in both breast- and prostate-cancer cells and inhibited growth of xenografts of both types of tumor cells. We tested whether RO treatment also enhanced tumor-suppressor ER-beta expression in ovarian cancer cells and whether ER-beta agonists might enhance the effects of RO. Using Western blot analysis, we found that RO indeed induced ERb expression in OVCAR-3 ovarian-cancer cells, and that treatment of two ovarian-cancer cell lines (OVCAR-3 and SK-OV-3) with liquiritigenin (LQ), a naturally occurring ER-beta agonist derived from plants, enhanced RO mediated reduction in vitro. Treatment with RO (5-10 uM), LQ (100-300 uM), or RO + LQ (multiple combinations of doses) reduced cell viability; RO + LQ combination treatment synergistically reduced cell viability. We predict that our observed in vitro effects will be translatable to in vivo models, given that we have already demonstrated that RO alone quite effectively inhibits the in vivo growth of EOC xenografts. Since treatment of ovarian cancer with existing anti-cancer drugs is accompanied by extreme side effects and drug resistance, we propose that low-dose combinations of RO and LQ should be further explored as a potential new therapy for combatting this disease. Our findings contribute to ongoing efforts to identify novel, effective treatments for primary and metastatic ovarian cancer that employ new non-toxic drugs. Further in vivo studies examining the effects of RO + LQ combination treatment on EOC are warranted as a means of exploring a potential new therapeutic approach to combat ovarian cancers with minimal toxicity. Citation Format: Yayun Liang, Salman Hyder. Liquiritigenin, an estrogen receptor beta agonist, enhances cholesterol biosynthesis inhibitor RO 48-8071-induced growth inhibition of ovarian cancer cells [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C091.

Statins Effects on Blood Clotting: A Review.

Statins are powerful lipid-lowering drugs that inhibit cholesterol biosynthesis via downregulation of hydroxymethylglutaryl coenzyme-A reductase, which are largely used in patients with or at risk of cardiovascular disease. Available data on thromboembolic disease include primary and secondary prevention as well as bleeding and mortality rates in statin users during anticoagulation for VTE. Experimental studies indicate that statins alter blood clotting at various levels. Statins produce anticoagulant effects via downregulation of tissue factor expression and enhanced endothelial thrombomodulin expression resulting in reduced thrombin generation. Statins impair fibrinogen cleavage and reduce thrombin generation. A reduction of factor V and factor XIII activation has been observed in patients treated with statins. It is postulated that the mechanisms involved are downregulation of factor V and activated factor V, modulation of the protein C pathway and alteration of the tissue factor pathway inhibitor. Clinical and experimental studies have shown that statins exert antiplatelet effects through early and delayed inhibition of platelet activation, adhesion and aggregation. It has been postulated that statin-induced anticoagulant effects can explain, at least partially, a reduction in primary and secondary VTE and death. Evidence supporting the use of statins for prevention of arterial thrombosis-related cardiovascular events is robust, but their role in VTE remains to be further elucidated. In this review, we present biological evidence and experimental data supporting the ability of statins to directly interfere with the clotting system.

CTNI-67. FIRST IN HUMAN STUDY OF DSP-0390, AN ORAL EMOPAMIL BINDING PROTEIN (EBP) INHIBITOR, IN RECURRENT HIGH-GRADE GLIOMA (HGG): PRELIMINARY RESULTS

Abstract BACKGROUND Cholesterol in the brain is derived wholly from de novo biosynthesis as the blood-brain barrier prevents uptake from the circulation. The overexpression of cholesterol synthesis genes is associated with decreased survival in glioblastoma (GBM), suggesting that gliomas may be sensitive to the inhibition of cholesterol biosynthesis. DSP-0390 is an investigational small molecule that inhibits EBP, a key enzyme in cholesterol biosynthesis. Preclinical studies demonstrated antitumor activity of DSP-0390 in orthotopic xenograft GBM models. METHODS This phase I dose escalation study aims to assess the safety, PK, PD, and preliminary antitumor activity of oral DSP-0390 monotherapy for recurrent HGG (NCT05023551). Key eligibility criteria include histologically confirmed grade III or IV glioma (WHO 2016); treatment with ≥ 1 prior therapy; no treatment options beyond standard of care; KPS ≥ 70. RESULTS As of 9 May 2023, 24 patients (37.5% women) were enrolled across 6 dose levels (20 mg QD to 240 mg QD) with a median age of 51 years (range 24-76) including 17 (70.8 %) with GBM, 3 (12.5%) with anaplastic astrocytoma and 2 (8.3%) with anaplastic oligodendroglioma. Ten patients (41.7%) had IDH mutant tumors. Four patients (16.7%) were on stable dose of corticosteroids at baseline, of which 2 were able to discontinue or dose reduce the corticosteroid while on DSP-0390. There were no reported DLTs. The most common treatment-related TEAEs included grade 1 or 2 nausea (7 patients [29.2%]) and alanine aminotransferase increased (6 patients [25.0%]). Only one grade 3 related AE (dry skin) was noted. Two patients with IDH mutant grade 3 glioma had tumor reduction and remain on DSP-0390 for ≥ 9 months. Dose dependent changes in PK and PD were observed. CONCLUSIONS DSP-0390 has been well tolerated to date with dose escalation ongoing. A dose response relationship was observed between PK and PD biomarkers.

The Transcription Factors NFATc1 and NFATc2 Control Glucocorticoid Resistance in Pediatric T-Cell Acute Lymphoblastic Leukemia

Background: The overall survival of pediatric T-cell Acute Lymphoblastic Leukemia (T-ALL) is significantly improved (˜75-80%) with the current therapeutic approaches. Nevertheless, for those patients that do not respond to conventional treatment and experience relapse, the prognosis is extremely poor. In this context, it is well defined that resistance to glucocorticoids (GCs), pillar drugs in the treatment protocol, can predispose pediatric T-ALL patients to a poor outcome. A pivotal role of LCK kinase has been elucidated in supporting GC resistance in T-ALL cells in our previous study and recently confirmed by other colleagues. However, to date, the biological processes modulated by LCK in this context are not yet defined. Aim: the identification of new mechanisms underlying GC resistance can lead to alternative therapeutic approaches to prevent or overcome GC resistance and ameliorate the outcome of this subgroup of patients. Methods and Results: we uncovered the involvement of NFATc1 and NFATc2 transcription factors, that act downstream LCK kinase, in guiding GC resistance in T-ALL cells. Of note, a high NFATc1 and NFATc2 transcriptional activity characterizes pediatric GC resistant T-ALL patients at diagnosis, that in turns show a low Glucocorticoid Receptor (GR) activity. In agreement, NFATc1 or NFATc2 specific gene silencing in 3 T-ALL GC resistant cell line models and primary cells increases dexamethasone response, by restoring GR canonical transcriptional activity through the increaseexpression of BIM GR targetgene (p value <0.05). Conversely, NFATc1 or NFATc2 overexpression in a murine T-ALL GC sensitive cell line confers resistance to dexamethasone treatment. Interestingly, by Gene Expression Profile (GEP) and Nuclear Magnetic Resonance (NMR) analysis, we observed that NFATc1 gene silencing in GC resistant cells significantly downregulates intracellular cholesterol abundance. Additionally, by Chromatin Immunoprecipitation (ChIP) we revealed that NFATc1 can directly control the transcription of HMGCS1, EBP and DHCR7, key enzymes of cholesterol biosynthesis process (n≥3, p value <0.05 for all the three genes). In agreement, exogenous cholesterol addition to NFATc1 knock-down cell lines rebuild dexamethasone resistance. Conversely, by GEP and flow cytometry analysis we observed that NFATc2 gene silencing in T-ALL GC resistant cells leads to a downregulation of the Wnt/β-catenin signaling pathway and to an increased T-cell differentiation. Furthermore, by ChIP analysis we revealed that in T-ALL GC resistant cells NFATc2 can directly affect the transcription of LRP6, a key Wnt/β-catenin signaling component (n=3, p value <0.05). In agreement, the Wnt/β-catenin signaling activation, by Wnt3a stimulation, restores dexamethasone resistance in NFATc2 knock-down T-ALL cells. Finally, we observed that the inhibition of cholesterol biosynthesis by simvastatin or of Wnt/β-catenin by PRI-724 increases GC sensitivity in T-ALL GC resistant cells by the High-Throughput drug synergism Screening (HTS) and the Highest Single Agent (HSA) approach. Conclusions: Overall, we revealed for the first time the involvement of NFATc1 and NFATc2 transcription factors in supporting GC resistance in T-ALL cells by the modulation of cholesterol biosynthesis and Wnt/β-catenin signaling, both processes well-described in sustaining chemotherapy resistance, paving the rationale to alternative therapeutic options for T-ALL GC resistant pediatric patients.

Inhibitory Perturbations of Fluvastatin on Afterhyperpolarization Current, Erg-mediated K+ Current, and Hyperpolarization-activated Cation Current in Both Pituitary GH3 Cells and Primary Embryonic Mouse Cortical Neurons.

Fluvastatin (FLV), the first synthetically derived 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, is a potent inhibitor of cholesterol biosynthesis. While its primary mechanism of action is to reduce cholesterol levels, there is some evidence suggesting that it may also have effects on K+ channels. However, the overall effects of fluvastatin on ionic currents are not yet well understood. The whole-cell clamp recordings were applied to evaluate the ionic currents and action potentials of cells. Here, we have demonstrated that FLV can effectively inhibit the amplitude of erg-mediated K+ current (IK(erg)) in pituitary tumor (GH3) cells, with an IC50 of approximately 3.2µM. In the presence of FLV, the midpoint in the activation curve of IK(erg) was distinctly shifted to a less negative potential by 10mV, with minimal modification of the gating charge. However, the magnitude of hyperpolarization-activated cation current (Ih) elicited by long-lasting membrane hyperpolarization was progressively decreased, with an IC50 value of 8.7µM, upon exposure to FLV. More interestingly, we also found that FLV (5µM) could regulate the action potential and afterhyperpolarization properties in primary embryonic mouse cortical neurons. Our study presents compelling evidence indicating that FLV has the potential to impact both the amplitude and gating of the ion channels IK(erg) and Ih. We also provide credible evidence suggesting that this drug has the potential to modify the properties of action potentials and the afterhyperpolarization current in electrically excitable cells. However, the assumption that these findings translate to similar in-vivo results remains unclear.

Cyclic fasting bolsters cholesterol biosynthesis inhibitors’ anticancer activity

Identifying oncological applications for drugs that are already approved for other medical indications is considered a possible solution for the increasing costs of cancer treatment. Under the hypothesis that nutritional stress through fasting might enhance the antitumour properties of at least some non-oncological agents, by screening drug libraries, we find that cholesterol biosynthesis inhibitors (CBIs), including simvastatin, have increased activity against cancers of different histology under fasting conditions. We show fasting’s ability to increase CBIs’ antitumour effects to depend on the reduction in circulating insulin, insulin-like growth factor-1 and leptin, which blunts the expression of enzymes from the cholesterol biosynthesis pathway and enhances cholesterol efflux from cancer cells. Ultimately, low cholesterol levels through combined fasting and CBIs reduce AKT and STAT3 activity, oxidative phosphorylation and energy stores in the tumour. Our results support further studies of CBIs in combination with fasting-based dietary regimens in cancer treatment and highlight the value of fasting for drug repurposing in oncology.

THU542 Inhibiting Oxidosqualene Cyclase Suppresses Cancer Stem-like Cells And Growth Of Epithelial Ovarian Cancer Cells In Vitro And In Vivo

Abstract Disclosure: Y. Liang: None. K.P. Nephew: None. S.M. Hyder: None. Epithelial ovarian cancer (EOC) is an aggressive and deadly disease and despite concerted efforts to develop new strategies for preventing and treating the disease, almost 25,000 new cases are reported each year in the United States. Unfortunately, patients with ovarian cancer have poor prognosis due to the emergence of drug resistant cells and subsequent metastasis and have the highest mortality rate of all known gynecological malignancies. Standard treatments include systemic high-dose toxic chemotherapeutic drugs, but drug-resistance almost always occurs. Consequently, novel and more effective non-toxic therapies for ovarian cancer are urgently needed. The biosynthetic pathway leading to cholesterol production is an attractive therapeutic target since cholesterol is an essential structural and functional component of cell membranes and is necessary for tumor growth. Treatment with statins, a class of cholesterol biosynthesis inhibitors that target HMGCoA-reductase, is associated with certain undesirable side effects; consequently, alternative approaches to inhibit cholesterol biosynthesis are being considered. Epithelial ovarian cancer cells express enzymes in the cholesterol biosynthetic pathway. With this is mind we inhibited a key enzyme in the pathway, oxidosqualene cyclase (OSC), with a view to disrupting cholesterol biosynthesis and disrupting the progression of ovarian cancer. Potent small molecule inhibitors of OSC have been identified, and RO 48-8071 (4′-[6-(allylmethylamino)hexyloxy]-4-bromo-2′-fluorobenzophenone fumarate) (RO), has emerged as a useful chemotherapeutic agent for treating breast and prostate cancer. Since OSC acts downstream of HMG-CoA reductase during cholesterol biosynthesis, its inhibition is not likely to be associated with the adverse effects caused by statins. We found in short-term assays (24-48 h) that pharmacological doses very effectively reduced the viability of ovarian tumor cells (SK-OV-3 and OVCAR-3), determined by Sulforhodamine B colorimetric assay. In long-term assays (7 days), nM concentrations of the drug were also effective. Importantly, RO (20-40 mg/kg/day; ip) significantly suppressed tumor xenografts derived from ovarian cancer cells (SK-OV-3; 336 + 60 mm3 vs 171 + 20 mm3) with no toxicity to experimental animals (27 treatments once tumors reached 100 mm3). Mechanistically, RO induced apoptosis in EOC, and suppressed ALDH activity, indicating that the inhibitor suppresses stem cell-like activity of EOC. Our study is the first to demonstrate disruption of cholesterol biosynthesis in human ovarian cancer cells as a novel and potent means by which to suppress their growth. Further studies will determine whether combining RO with chemotherapeutic drugs is an even more effective therapeutic approach to EOC, and examine the effects of RO on combating the development of drug-resistant ovarian cancer. Presentation: Thursday, June 15, 2023

KAJIANPUSTAKA: HIPERKOLESTEROLEMIADAN PENANGGULANGANNYA DENGAN MENGGUNAKANBERBAGAI SENYAWA BIOAKTIF

Hypercholesterolemia is characterized by levels of total cholesterol and low-density lipoprotein (LDL) above normal. Hypercholesterolemia is a major risk factor for cardiovascular disease. This study was aimed to explore and analyze various bioactive compounds to manage hypercholesterolemia. Efforts to overcome the condition of hypercholesterolemia are to reduce the consumption of a diet rich in cholesterol and calories, and consuming contemporary hypercholesterolemic drugs such as statins, as well as by regulating the body’s cholesterol metabolism with various antihypercholesterolemic bioactive compounds. Various findings of antihypercholesterolemic bioactive compounds have various sources and effects on cholesterol profiles. Bioactive compounds can be classified according to their mechanism of hypocholesterolemic action, which are inhibition of cholesterol absorption, inhibition of cholesterol biosynthesis, increased cholesterol excretion, increased cholesterol reverse transport, and increased cholesterol catabolism. Several bioactive compounds are involved in a dual mechanism. The development of these various bioactive compounds can be used as an alternative treatment for hypercholesterolemia since contemporary medicines have proven to have many side effects.

Chemical synthesis and biochemical properties of cholestane-5α,6β-diol-3-sulfonate: A non-hydrolysable analogue of cholestane-5α,6β-diol-3β-sulfate

Cholestane-3β,5α,6β-triol (CT) is a primary metabolite of 5,6-epoxycholesterols (5,6-EC) that is catalyzed by the cholesterol-5,6-epoxide hydrolase (ChEH). CT is a well-known biomarker for Niemann-Pick disease type C (NP-C), a progressive inherited neurodegenerative disease. On the other hand, CT is known to be metabolized by the 11β-hydroxysteroid-dehydrogenase of type 2 (11β-HSD2) into a tumor promoter named oncosterone that stimulates the growth of breast cancer tumors. Sulfation is a major metabolic transformation leading to the production of sulfated oxysterols. The production of cholestane-5α,6β-diol-3β-O-sulfate (CDS) has been reported in breast cancer cells. However, no data related to CDS biological properties have been reported so far. These studies have been hampered because sulfate esters of sterols and steroids are rapidly hydrolyzed by steroid sulfatase to give free steroids and sterols. In order to get insight into the biological properties of CDS, we report herein the synthesis and the characterization of cholestane-5α,6β-diol-3β-sulfonate (CDSN), a non-hydrolysable analogue of CDS. We show that CDSN is a potent inhibitor of 11β-HSD2 that blocks oncosterone production on cell lysate. The inhibition of oncosterone biosynthesis of a whole cell assay was observed but results from the blockage by CDSN of the uptake of CT in MCF-7 cells. While CDSN inhibits MCF-7 cell proliferation, we found that it potentiates the cytotoxic activity of post-lanosterol cholesterol biosynthesis inhibitors such as tamoxifen and PBPE. This effect was associated with an increase of free sterols accumulation and the appearance of giant multilamellar bodies, a structural feature reminiscent of Type C Niemann-Pick disease cells and consistent with a possible inhibition by CDSN of NPC1. Altogether, our data showed that CDSN is biologically active and that it is a valuable tool to study the biological properties of CDS and more specifically its impact on immunity and viral infection.