UPR/ATF4/Noxa pathway over-activation through SERCA2 inhibition or ONC201 treatment combined with ABT-737 triggers apoptosis in chemoresistant ovarian cancer cells and patient-derived tumour organoids

UPR/ATF4/Noxa pathway over-activation through SERCA2 inhibition or ONC201 treatment combined with ABT-737 triggers apoptosis in chemoresistant ovarian cancer cells and patient-derived tumour organoids | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article UPR/ATF4/Noxa pathway over-activation through SERCA2 inhibition or ONC201 treatment combined with ABT-737 triggers apoptosis in chemoresistant ovarian cancer cells and patient-derived tumour organoids Monique N'DIAYE, Sahra Messaoudi, ROMANE FLORENT, Louis-Bastien Weiswald, and 10 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6768426/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 27 Mar, 2026 Read the published version in Cell Death & Disease → Version 1 posted 9 You are reading this latest preprint version Abstract Ovarian cancer has a poor clinical prognosis due to chemoresistance following carboplatin/paclitaxel treatment. This phenomenon can be explained by an imbalanced ratio of [anti-apoptotic (BCL-xL/MCL-1)] to [pro-apoptotic (Noxa, BIM, PUMA)] BCL-2 family members that prevents apoptosis initiation. Consequently, any treatment capable of counterbalancing this ratio could be beneficial in the management of ovarian cancer. Calcium signalling is strongly implicated in resistance to apoptosis, as it depends on, but also regulates, the expression of the ratio of BCL-2 family members, making calcium-targeted strategies relevant to overcoming chemoresistance. Knowing that SERCA2 calcium pumps regulation play a major role in controlling the ER stress-induced UPR response that could lead to pro-apoptotic protein up-regulation and cell death, we therefore evaluated whether their inhibition could elicit apoptosis or sensitise ovarian cancer cells to other therapeutic strategies. For this purpose, the platinum-resistant cell line, OAW42-R, was treated with anti-SERCA2 strategies which revert the BCL-2 family member expression ratio in favour of pro-apoptotic proteins. Combination with the BH3-mimetic ABT-737 exacerbates this imbalance not only by inhibiting BCL-xL activity but also through over-induction of the UPR/ATF4/Noxa axis leading to MCL-1 inhibition. This dual effect of ABT-737 upon ER stress fully suppresses the anti-apoptotic capacities of cancer cells leading to massive mitochondrial apoptosis. This point was supported with ONC201, the first member of the imipridone family of anticancer drugs to enter the clinic, whose ability to trigger UPR/ATF4/Noxa led to apoptosis commitment when it was combined with ABT-737 treatment. The therapeutic efficacy of these combinations was also proved in patient-derived-tumour-organoids models (PDTO) leading to their structural disintegration and reduced viability. Collectively, our study highlights that ABT 737, through BCL-xL inhibition and synergy with ER stress inducers, triggers ovarian cancer death, offering promising strategies for overcoming chemoresistance in relapsed ovarian cancer. Biological sciences/Cancer/Cancer therapy/Cancer therapeutic resistance Biological sciences/Cell biology/Cell death/Apoptosis Biological sciences/Cancer/Gynaecological cancer/Ovarian cancer Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Full Text Additional Declarations (Not answered) Supplementary Files SupplementaryFigure1Messaoudietal.pdf Supplementary Figure S1 SupplementaryFigure2Messaoudietal.pdf Supplementary Figure S2 SupplementaryFigure3Messaoudietal.pdf Supplementary Figure S3 SupplementaryFigure4Messaoudietal.pdf Supplementary Figure S4 OriginalWB.pdf Original WB LegendsSupplementaryFiguresMessaoudietal.pdf Legends Supplementary Figures Cite Share Download PDF Status: Published Journal Publication published 27 Mar, 2026 Read the published version in Cell Death & Disease → Version 1 posted Editorial decision: revise 08 Jul, 2025 Review # 1 received at journal 01 Jul, 2025 Review # 2 received at journal 30 Jun, 2025 Reviewer # 2 agreed at journal 30 Jun, 2025 Reviewer # 1 agreed at journal 11 Jun, 2025 Reviewers invited by journal 10 Jun, 2025 Submission checks completed at journal 29 May, 2025 Editor assigned by journal 28 May, 2025 First submitted to journal 28 May, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6768426","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":469148967,"identity":"a63635bf-c27d-4ef2-be0c-c69e911d5bd8","order_by":0,"name":"Monique N'DIAYE","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABBklEQVRIiWNgGAWjYJCCAxAqsQFI2DAwMEO4/MRqSYNrkWwgbFkCiDgM5+LUotvee/DA2zYbBnP25MbPPBXnE7ezMz/88HEHg4Q5Dj1mZ84lHJzblsZg2fOwWZrnzO3Enc1sxpIzzzBIyBzAoeVGjsFh3rbDDAY3EhukedtuJ244zMMAZDDUSeBwGFTLf5CW5t+8/86BtDD//tvGIEFAywGQljZp3oYDIC1s0oz4tJw5Y3BwzrlkHoMzD9ss5xxLNt5wmM3MsrdNAreW4z3GH96U2ckZHE9/fONNjZ3shvOHH9/42WaDUwsY8IARAwMTD0IMrwaoeiBg/IFf3SgYBaNgFIxQAABgFF6kPJvQXgAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0001-8867-0778","institution":"Université de Caen Normandie","correspondingAuthor":true,"prefix":"","firstName":"Monique","middleName":"","lastName":"N'DIAYE","suffix":""},{"id":469148968,"identity":"6637f9ba-23a8-4096-a293-4d72724ff123","order_by":1,"name":"Sahra Messaoudi","email":"","orcid":"","institution":"Université de Caen Normandie","correspondingAuthor":false,"prefix":"","firstName":"Sahra","middleName":"","lastName":"Messaoudi","suffix":""},{"id":469148969,"identity":"e9c80a24-0c1f-4228-b1f7-45770d6a1f6f","order_by":2,"name":"ROMANE FLORENT","email":"","orcid":"","institution":"NORMANDIE UNIVERSITE - UNICAEN","correspondingAuthor":false,"prefix":"","firstName":"ROMANE","middleName":"","lastName":"FLORENT","suffix":""},{"id":469148970,"identity":"62578ca4-1e11-44e5-aa25-befe3ce0fbf9","order_by":3,"name":"Louis-Bastien Weiswald","email":"","orcid":"https://orcid.org/0000-0001-6935-100X","institution":"University of Caen Normandy","correspondingAuthor":false,"prefix":"","firstName":"Louis-Bastien","middleName":"","lastName":"Weiswald","suffix":""},{"id":469148971,"identity":"ca70d217-5a67-4e8e-b925-9c235cce998a","order_by":4,"name":"Guillaume Desmartin","email":"","orcid":"","institution":"Université de Caen Normandie and UNICANCER","correspondingAuthor":false,"prefix":"","firstName":"Guillaume","middleName":"","lastName":"Desmartin","suffix":""},{"id":469148972,"identity":"117f7c76-128d-4955-82ba-9466edb5ccb5","order_by":5,"name":"Lucie Lecouflet","email":"","orcid":"","institution":"Université de Caen Normandie and UNICANCER","correspondingAuthor":false,"prefix":"","firstName":"Lucie","middleName":"","lastName":"Lecouflet","suffix":""},{"id":469148973,"identity":"ef1572f6-68fc-46af-b491-63ab26f90414","order_by":6,"name":"Steven Lohard","email":"","orcid":"","institution":"Université de Caen Normandie","correspondingAuthor":false,"prefix":"","firstName":"Steven","middleName":"","lastName":"Lohard","suffix":""},{"id":469148974,"identity":"f5ece060-48ba-4c28-a06a-876f4682f5ff","order_by":7,"name":"Léa Grunchec","email":"","orcid":"","institution":"Université de Caen Normandie","correspondingAuthor":false,"prefix":"","firstName":"Léa","middleName":"","lastName":"Grunchec","suffix":""},{"id":469148975,"identity":"6fd46b88-6dc2-448e-9734-febec46b804b","order_by":8,"name":"Edwige Abeilard","email":"","orcid":"","institution":"Comprehensive Cancer Center F. Baclesse and University of Caen Basse-Normandie","correspondingAuthor":false,"prefix":"","firstName":"Edwige","middleName":"","lastName":"Abeilard","suffix":""},{"id":469148976,"identity":"5105c083-fd35-4f90-819a-6a83fe241b98","order_by":9,"name":"Marilyne Guillamin","email":"","orcid":"","institution":"Université de Caen Normandie","correspondingAuthor":false,"prefix":"","firstName":"Marilyne","middleName":"","lastName":"Guillamin","suffix":""},{"id":469148977,"identity":"b4c2cedc-11dd-4d41-a1b9-de21e98a3f8c","order_by":10,"name":"Jordane Divoux","email":"","orcid":"","institution":"Université de Caen Normandie and UNICANCER","correspondingAuthor":false,"prefix":"","firstName":"Jordane","middleName":"","lastName":"Divoux","suffix":""},{"id":469148978,"identity":"834a8f82-f98d-4205-ab82-3839f60a72dc","order_by":11,"name":"Benoît Goudergues","email":"","orcid":"","institution":"Université de Caen Normandie and UNICANCER","correspondingAuthor":false,"prefix":"","firstName":"Benoît","middleName":"","lastName":"Goudergues","suffix":""},{"id":469148979,"identity":"6f57d662-62f4-40a6-a398-051c321e8da3","order_by":12,"name":"Enora Dolivet","email":"","orcid":"","institution":"Université de Caen Normandie and UNICANCER","correspondingAuthor":false,"prefix":"","firstName":"Enora","middleName":"","lastName":"Dolivet","suffix":""},{"id":469148980,"identity":"9c638482-4810-49b3-a0b6-5314974a6679","order_by":13,"name":"Laurent Poulain","email":"","orcid":"","institution":"CLCC F. Baclesse and University of Caen Basse-Normandie","correspondingAuthor":false,"prefix":"","firstName":"Laurent","middleName":"","lastName":"Poulain","suffix":""}],"badges":[],"createdAt":"2025-05-28 13:15:48","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6768426/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6768426/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41419-026-08559-7","type":"published","date":"2026-03-27T04:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":84735506,"identity":"6d7a317c-5569-48f6-98db-c055be2db7d1","added_by":"auto","created_at":"2025-06-16 18:19:51","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":361952,"visible":true,"origin":"","legend":"\u003cp\u003eSERCA2 targeting with si-RNA and thapsigargin induces BH3-only protein expression and sensitises OAW42-R cell line to ABT-737 Chemoresistant OAW42-R cells were either transfected 72 h with 20 nM si-control (si-CT) or si-SERCA2 (left column) or treated with 0,5 µM thapsigargin (TG) for 24 h and 48 h (right column) and the effects were investigated A on cell morphology by optical microscopy (scale bar = 200 µM), B on cell proliferation by the Trypan blue exclusion test (histograms represent the percentage of viable cells in the transfected conditions normalized to that of no transfected one (100%) (left column) and in the treated condition normalized to that of T0 condition (100%) (right column)), and C on the BCL-2 family members expression using western blot analysis. Protein expression levels were quantified using ImageJ software and normalized to that of actin for the si-CT or DMSO. OAW42-R were transfected with 20 nM si-CT or si-SERCA2 for 72 h followed by a 24h-treatment with 5 µM ABT-737 (left column) or cotreated with 0,5 µM thapsigargin and 5 µM ABT-737 for 24 h (right column) and their effects were assessed on D cell morphology by optical microscopy (scale bar = 200 µM), E cell proliferation by the Trypan blue exclusion test (histograms represent the percentage of viable cells in each conditions normalized to that of control condition (100%)) (N=3 for all experiments). Results were considered statistically different if *p \u0026lt; 0.05, **p \u0026lt; 0.01, ***p \u0026lt; 0.001.\u003c/p\u003e","description":"","filename":"Binder11.png","url":"https://assets-eu.researchsquare.com/files/rs-6768426/v1/fcf5ab3acbe545b5fd488b30.png"},{"id":84736444,"identity":"199823be-608d-47b6-9c2c-380212381732","added_by":"auto","created_at":"2025-06-16 18:35:52","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":404408,"visible":true,"origin":"","legend":"\u003cp\u003eSERCA2 targeting sensitises OAW42-R cell line to ABT-737 by inducing apoptosis \u0026nbsp;OAW42-R were transfected with 20 nM si-CT or si-SERCA2 for 72 h followed by a 10 h treatment with 5 µM ABT-737 (left column) or cotreated with 0,5 µM thapsigargin and 5 µM \u0026nbsp;ABT-737 for 6 h (right column). Apoptosis involvement was investigated, A by measuring \u0026nbsp;Annexin V/FITC events using flow cytometry and, B by analysing PARP and CASPASE 3 \u0026nbsp;cleavages by western blot (N=3). Effects of 50 µM Z-VAD were investigated in OAW42-R cells. \u0026nbsp;Cells were either transfected 72 h with si-SERCA2 then pre-treated with Z-VAD for 1h30 and \u0026nbsp;finally treated with ABT-737 for 24 h, or pre-treated with Z-VAD for 1h30 and treated with 0.5 µM thapsigargin + 5 µM ABT-737 for 24 h. Apoptosis involvement was investigated C on cell \u0026nbsp;morphology by optical microscopy (scale bar = 200 µM), D on cell viability by the Trypan blue \u0026nbsp;exclusion test (histograms represent the percentage of viable cells normalized to that of control \u0026nbsp;condition (100%)) and, E by the observation of CASPASE 3 cleavage by western blot (N=3). \u0026nbsp;Results were considered statistically different if *p \u0026lt; 0.05, **p \u0026lt; 0.01, ***p \u0026lt; 0.001.\u003c/p\u003e","description":"","filename":"Binder12.png","url":"https://assets-eu.researchsquare.com/files/rs-6768426/v1/f3629b789dd81bad8c0ac53b.png"},{"id":84735511,"identity":"18a187bf-3b35-4af1-b9e4-def643025575","added_by":"auto","created_at":"2025-06-16 18:19:52","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":431632,"visible":true,"origin":"","legend":"\u003cp\u003eSERCA2 targeting strategies synergise with ABT-737 treatment leading to Noxa overexpression that triggers apoptosis A Pro-apoptotic BIM, PUMA and Noxa protein expression were investigated by western blot after both combinations in OAW42-R cells (N=3). Cells were co-transfected with 10 nM si-Noxa and 10 nM si-SERCA2 for 72 h then treated with 5 µM ABT-737 for 24 h (left column) (N=3) or transfected 24 h with 20 nM si-Noxa then treated 24 h with 0,5 µM thapsigargin + 5 µM ABT‑737 (right column) (N=4). Cell death was investigated on B cell morphology by optical microscopy (scale bar = 200 µM), C cell viability by the Trypan blue exclusion test (histograms represent the percentage of viable cells normalized to that of control condition (100%)) and on, D the expression of CASPASE 3 cleavage by western blot. Results were considered statistically different if *p \u0026lt; 0.05, **p \u0026lt; 0.01, ***p \u0026lt; 0.001.\u003c/p\u003e","description":"","filename":"Binder13.png","url":"https://assets-eu.researchsquare.com/files/rs-6768426/v1/e6d531b53634da808b23f7e4.png"},{"id":84736446,"identity":"d1a39363-080c-4552-905c-0540ee31b4b7","added_by":"auto","created_at":"2025-06-16 18:35:52","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":132969,"visible":true,"origin":"","legend":"\u003cp\u003eNoxa protein increase is controlled by ER stress-induced ATF4 transcription factor A Expression of PMAIP1 mRNA (coding Noxa protein) was investigated by RT-qPCR after both combinations in OAW42-R cells (si-SERCA2+ABT-737: left column and TG+ABT‑737: right column). B ATF4 mRNA expression was evaluated by RT-qPCR and C expression of ER stress markers BiP, ATF4 and CHOP were assessed by western blot. After 72h-transfection with 20 nM si-SERCA2, cells were transfected 24 h with 20 nM si-ATF4 followed by a 24h treatment with 5 µM ABT-737 (left column) or transfected with 20 nM si-ATF4 followed by a 24h-treatment with 0.5 µM thapsigargin + 5 µM ABT-737 (right column) and D PMAIP1 mRNA expression was analysed by RT-qPCR and E Noxa, CHOP and ATF4 protein expression were assessed by western blot. Results were considered statistically different if *p \u0026lt; 0.05, **p \u0026lt; 0.01, ***p \u0026lt; 0.001, ****p\u0026lt; 0.0001. (N=3 for all experiments)\u003c/p\u003e","description":"","filename":"Binder14.png","url":"https://assets-eu.researchsquare.com/files/rs-6768426/v1/4a9162e0720f0e73138373b2.png"},{"id":84736146,"identity":"a1c2633d-f9e1-4a12-b17d-02d1ea754c2e","added_by":"auto","created_at":"2025-06-16 18:27:52","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":392808,"visible":true,"origin":"","legend":"\u003cp\u003eONC201 synergises with ABT-737 to induce apoptosis through ER stress/ATF4/Noxa pathway. Effects of 5 µM ONC201 were investigated in OAW42-R cells after 24 and 48 h treatment A on cell morphology by optical microscopy (scale bar = 200 µM; 24 h-treatment) B on cell proliferation by the Trypan blue exclusion test (histograms represent the percentage of viable cells in the treated conditions normalized to that of T0 condition (100%)). C Expression of ONC201 activity markers (BiP, ATF4, DR5 and cleaved CASPASE 8) and BCL-2 family members were assessed by western blot analysis after 24 h treatment with ONC201 5 µM (N=3). Effects of a 24h-cotreatment with 5 µM ONC201 + 5 µM ABT‑737 were investigated in OAW42-R cells on D cell morphology by optical microscopy (scale bar = 200 µM), E cell viability assessed by the Trypan blue exclusion test (histograms represent the percentage of viable cells normalized to that of the control condition (100%)), on F apoptosis marker expression by analysing CASPASE 3 cleavage by western blot, and on G BiP, ATF4 and Noxa protein expression by western blot (N=3). Cells were transfected with 20 nM si-Noxa for 24 h then treated with 5 µM ONC201 in presence or in absence of 5 µM ABT-737. H Cell morphology was analysed by optical microscopy (scale bar = 200 µM), I cell proliferation by the Trypan blue exclusion test (histograms represent the percentage of viable cells in the treated conditions normalized to that of control condition (100%)) and J apoptosis triggering was assessed by observation of CASPASE 3 cleavage by western blot (N=3). Results were considered statistically different if *p \u0026lt; 0.05, **p \u0026lt; 0.01, ***p \u0026lt; 0.001.\u0026nbsp;\u003c/p\u003e","description":"","filename":"Binder15.png","url":"https://assets-eu.researchsquare.com/files/rs-6768426/v1/ec1846aa02e76eba47ffb630.png"},{"id":84735516,"identity":"9719e9e2-ef47-4b90-81cb-daa64c9dd307","added_by":"auto","created_at":"2025-06-16 18:19:52","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":545494,"visible":true,"origin":"","legend":"\u003cp\u003eThapsigargin or ONC201 combined with ABT-737 triggers apoptotic cell death in PDTOs. Two naïve PDTOs lines (OV-130-A and OV-253-T) from patients with chemoresistant HGSOC were treated with 0,5 µM thapsigargin and increasing concentrations of ABT-737 for 24 h (left column) or with 5 µM ABT‑737 with increasing concentrations of ONC201 (right column). PDTOs viability was measured in each condition by Cell TiterGlo assay (histograms represent the percentage of PDTO viability in treated conditions normalized to that of control condition) (upper panels). Morphological effect on PDTO was assessed by optical microscopy (scale bar = 200μm) (lower panels). A Results for OV-130-A PDTOs line (N=4 and N=3), B results for OV-253-T PDTOs line (N=6 and N=4). C OV-253-T PDTOs line was co-treated with 5 µM ONC201 and 5 µM ABT-737 for 24 h and expression of ONC201 activity markers (DR5, cleaved CASPASE 8), ER stress markers (BiP, ATF4), Noxa and the apoptosis marker (cleaved CASPASE 3) were assessed (N=3).\u003c/p\u003e","description":"","filename":"Binder16.png","url":"https://assets-eu.researchsquare.com/files/rs-6768426/v1/cfd512da2af4d72842d95b93.png"},{"id":108669240,"identity":"5826f0a5-7fe0-4ff6-8b6f-da12c4fd409f","added_by":"auto","created_at":"2026-05-07 07:15:32","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1816647,"visible":true,"origin":"","legend":"Article File","description":"","filename":"ManuscriptMessaoudietal.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6768426/v1_covered_7b387688-aa32-4dd8-a53a-51c45399f1ce.pdf"},{"id":84735507,"identity":"ebf2608b-a036-40ba-afb6-b7b59d58503d","added_by":"auto","created_at":"2025-06-16 18:19:51","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":82581,"visible":true,"origin":"","legend":"Supplementary Figure S1","description":"","filename":"SupplementaryFigure1Messaoudietal.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6768426/v1/608d2081793106810ec378a6.pdf"},{"id":84735513,"identity":"362a24b4-7dd4-4fe2-a4dd-0ac8bb4b8378","added_by":"auto","created_at":"2025-06-16 18:19:52","extension":"pdf","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":333520,"visible":true,"origin":"","legend":"Supplementary Figure S2","description":"","filename":"SupplementaryFigure2Messaoudietal.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6768426/v1/60009d97c754f0f7a1d95839.pdf"},{"id":84736143,"identity":"785bb051-9595-45b2-819a-64d7ac689b76","added_by":"auto","created_at":"2025-06-16 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18:27:52","extension":"pdf","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":1378249,"visible":true,"origin":"","legend":"Original WB","description":"","filename":"OriginalWB.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6768426/v1/dd7d3cf17ad9a2b61a5d6601.pdf"},{"id":84735515,"identity":"6ff0b3c8-733b-49fe-8f74-aa14de8e497b","added_by":"auto","created_at":"2025-06-16 18:19:52","extension":"pdf","order_by":6,"title":"","display":"","copyAsset":false,"role":"supplement","size":34373,"visible":true,"origin":"","legend":"Legends Supplementary Figures","description":"","filename":"LegendsSupplementaryFiguresMessaoudietal.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6768426/v1/712c1b367484737ffc5f83ec.pdf"}],"financialInterests":"(Not answered)","formattedTitle":"UPR/ATF4/Noxa pathway over-activation through \r\nSERCA2 inhibition or ONC201 treatment combined with ABT-737 triggers apoptosis \r\nin chemoresistant ovarian cancer cells and patient-derived tumour organoids","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"cell-death-and-disease","isNatureJournal":false,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"cddis","sideBox":"Learn more about [Cell Death \u0026 Disease](http://www.nature.com/cddis/)","snPcode":"41419","submissionUrl":"https://mts-cddis.nature.com/cgi-bin/main.plex","title":"Cell Death \u0026 Disease","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-6768426/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6768426/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Ovarian cancer has a poor clinical prognosis due to chemoresistance following carboplatin/paclitaxel treatment. This phenomenon can be explained by an imbalanced ratio of [anti-apoptotic (BCL-xL/MCL-1)] to [pro-apoptotic (Noxa, BIM, PUMA)] BCL-2 family members that prevents apoptosis initiation. Consequently, any treatment capable of counterbalancing this ratio could be beneficial in the management of ovarian cancer. Calcium signalling is strongly implicated in resistance to apoptosis, as it depends on, but also regulates, the expression of the ratio of BCL-2 family members, making calcium-targeted strategies relevant to overcoming chemoresistance. Knowing that SERCA2 calcium pumps regulation play a major role in controlling the ER stress-induced UPR response that could lead to pro-apoptotic protein up-regulation and cell death, we therefore evaluated whether their inhibition could elicit apoptosis or sensitise ovarian cancer cells to other therapeutic strategies. For this purpose, the platinum-resistant cell line, OAW42-R, was treated with anti-SERCA2 strategies which revert the BCL-2 family member expression ratio in favour of pro-apoptotic proteins. Combination with the BH3-mimetic ABT-737 exacerbates this imbalance not only by inhibiting BCL-xL activity but also through over-induction of the UPR/ATF4/Noxa axis leading to MCL-1 inhibition. This dual effect of ABT-737 upon ER stress fully suppresses the anti-apoptotic capacities of cancer cells leading to massive mitochondrial apoptosis. This point was supported with ONC201, the first member of the imipridone family of anticancer drugs to enter the clinic, whose ability to trigger UPR/ATF4/Noxa led to apoptosis commitment when it was combined with ABT-737 treatment. The therapeutic efficacy of these combinations was also proved in patient-derived-tumour-organoids models (PDTO) leading to their structural disintegration and reduced viability. Collectively, our study highlights that ABT 737, through BCL-xL inhibition and synergy with ER stress inducers, triggers ovarian cancer death, offering promising strategies for overcoming chemoresistance in relapsed ovarian cancer.","manuscriptTitle":"UPR/ATF4/Noxa pathway over-activation through \nSERCA2 inhibition or ONC201 treatment combined with ABT-737 triggers apoptosis \nin chemoresistant ovarian cancer cells and patient-derived tumour organoids","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-16 18:19:47","doi":"10.21203/rs.3.rs-6768426/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"revise","date":"2025-07-08T16:24:12+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"This content is not available.","date":"2025-07-01T06:28:29+00:00","index":1,"fulltext":"This content is not available."},{"type":"editorInvitedReview","content":"This content is not available.","date":"2025-06-30T16:19:35+00:00","index":2,"fulltext":"This content is not available."},{"type":"reviewerAgreed","content":"This content is not available.","date":"2025-06-30T08:38:45+00:00","index":2,"fulltext":"This content is not available."},{"type":"reviewerAgreed","content":"This content is not available.","date":"2025-06-11T16:36:47+00:00","index":1,"fulltext":"This content is not available."},{"type":"reviewersInvited","content":"","date":"2025-06-10T10:18:24+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-29T08:56:22+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-28T13:12:40+00:00","index":"","fulltext":""},{"type":"submitted","content":"Cell Death \u0026 Disease","date":"2025-05-28T13:12:39+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"cell-death-and-disease","isNatureJournal":false,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"cddis","sideBox":"Learn more about [Cell Death \u0026 Disease](http://www.nature.com/cddis/)","snPcode":"41419","submissionUrl":"https://mts-cddis.nature.com/cgi-bin/main.plex","title":"Cell Death \u0026 Disease","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"040038ae-812c-423a-b1ef-2b3a6c871923","owner":[],"postedDate":"June 16th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":49809706,"name":"Biological sciences/Cancer/Cancer therapy/Cancer therapeutic resistance"},{"id":49809707,"name":"Biological sciences/Cell biology/Cell death/Apoptosis"},{"id":49809708,"name":"Biological sciences/Cancer/Gynaecological cancer/Ovarian cancer"}],"tags":[],"updatedAt":"2026-05-07T07:15:23+00:00","versionOfRecord":{"articleIdentity":"rs-6768426","link":"https://doi.org/10.1038/s41419-026-08559-7","journal":{"identity":"cell-death-and-disease","isVorOnly":false,"title":"Cell Death \u0026 Disease"},"publishedOn":"2026-03-27 04:00:00","publishedOnDateReadable":"March 27th, 2026"},"versionCreatedAt":"2025-06-16 18:19:47","video":"","vorDoi":"10.1038/s41419-026-08559-7","vorDoiUrl":"https://doi.org/10.1038/s41419-026-08559-7","workflowStages":[]},"version":"v1","identity":"rs-6768426","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6768426","identity":"rs-6768426","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}