Evidence map›Paper›PMID 42823448›Full record

ArticleOncogene2026

Nuclear cathepsin L induces DNA damage by regulating DNA repair factors in ovarian cancer.

Prabhu Thirusangu, Upasana Ray, Ling Jin, Biswajit Das, Christopher L Pathoulas, Julie Staub, Ann L Oberg, Xiaonan Hou, Jamison L VanBlaricom, Nagarajan Kannan and 3 more

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Article in Oncogene, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

13 authors.

Prabhu Thirusangu *Department of Experimental Pathology and Medicine, Mayo Clinic, Rochester, MN, USA.
Upasana Ray *Department of Experimental Pathology and Medicine, Mayo Clinic, Rochester, MN, USA.
Ling Jin *Department of Experimental Pathology and Medicine, Mayo Clinic, Rochester, MN, USA.
Biswajit DasDepartment of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA, USA.
Christopher L PathoulasDepartment of Experimental Pathology and Medicine, Mayo Clinic, Rochester, MN, USA.
Julie StaubDepartment of Experimental Pathology and Medicine, Mayo Clinic, Rochester, MN, USA.ORCID http://orcid.org/0000-0002-7939-6882
Ann L ObergDepartment of Oncology, Mayo Clinic, Rochester, MN, USA.ORCID http://orcid.org/0000-0003-2539-9807
Xiaonan HouDepartment of Oncology, Mayo Clinic, Rochester, MN, USA.
Jamison L VanBlaricomDepartment of Oncology, Mayo Clinic, Rochester, MN, USA.
Nagarajan KannanDepartment of Experimental Pathology and Medicine, Mayo Clinic, Rochester, MN, USA.ORCID http://orcid.org/0000-0002-8825-2178
John WerohaDepartment of Oncology, Mayo Clinic, Rochester, MN, USA.ORCID http://orcid.org/0000-0002-7130-7259
Jamie N Bakkum-GamezDepartment of Oncology, Mayo Clinic, Rochester, MN, USA.
Viji ShridharDepartment of Experimental Pathology and Medicine, Mayo Clinic, Rochester, MN, USA. shridhar.vijayalakshmi@mayo.edu.ORCID http://orcid.org/0000-0001-7232-0802

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Resistance to PARP inhibitors (PARPi) remains a major clinical challenge in ovarian cancer (OC), emphasizing the need for novel strategies to enhance therapeutic efficiency. Our previous work revealed that the antimalarial drug quinacrine (QC) can be repurposed to induce cell death in OC by promoting lysosomal release of active cathepsin L (CTSL). Building on these outcomes, we investigated whether QC-activated CTSL influences DNA damage and homologous recombination (HR) repair in OC cells. Our experimental evidence shows that QC-activated CTSL downregulates key DNA repair proteins RAD51 and 53BP1, leading to impaired HR repair and increased DNA damage. Importantly, genetic knockdown of CTSL significantly reduced QC-induced DNA damage, confirming the CTSL plays a direct functional role in this process. We also found out that the response of combined QC and PARPi differs in models. CTSL was translocated to the nucleus (nCTSL) in responsive patient-derived ascitic (PDA) and patient-derived xenograft (PDX) spheroids. Contrarily, non-responsive models did not have nuclear CTSL. Mechanically, QC could not suppress CRM1/XPO1 nuclear export receptor in non-responsive cells, leading to continued export of CTSL from the nucleus. To address this, we have used the CRM1 inhibitor KPT-8602, which restored nuclear retention of CTSL. This led to enhanced therapeutic synergy with PARPi and overcame resistance in QC-treated PDA 3D-spheroids. Consistent with these findings, QC reduced tumor burden in both the cell-derived OVCAR-5 xenograft and PDX-PH070 models that showed QC-induced nCTSL, but not in the non-responsive PDX-PH095 model. However, in additional non-responsive PDX models (PH747 and PH081), treatment with QC and KPT-8602 substantially reduced tumor burden. Collectively, our results confirm a critical role for nuclear CTSL in QC-induced DNA damage and identify nCTSL as a possible predictive biomarker of therapeutic response. These results suggest that combining QC with PARPi or CRM1 inhibitors represents a promising strategy to overcome PARPi resistance in OC.

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