Journal: bioRxiv

Article Title: PROTAC-Driven Protective Therapy increases the therapeutic window of anticancer drugs

doi: 10.64898/2026.01.12.698947

Figure Lengend Snippet: A) Structure of SK-575 PROTAC formed by the PARPi Olaparib linked to Thalidomide, a CRBN binder. B) Western blot analysis of PARP1 expression in isogenic CRBN WT and KO KBM7 cells treated with 100 nM SK-575 or Thalidomide for 48h. ACTB was used as loading control. C) Viability assay by MTT performed in CRBN WT or KO KBM7 cells pre-treated with 100 nM SK-575 for 24 h followed by a treatment with both SK-575 and the indicated doses of Olaparib or Talazoparib for another 24 h. Data are normalized to vehicle or SK-575 pre-treated cells and correspond to three biological replicates. IC50s were calculated with non-linear regression analysis and are shown in the figure (µM). Statistical significance was determined with Extra sum-of-squares F test. D) Analysis of percentage of viability as assessed by Annexin V/PI staining using flow cytometry analysis from three biological replicates. Statistical significance was determined with Ordinary one-way ANOVA and Tukey’s multiple comparisons test. E) Representative images of the Annexin V/PI staining. Percentage of cells for each population are shown. F) Western blot showing PARP1 degradation in human bone marrow mononuclear cells treated with 100 nM SK-575 for 48 h. G) Colony-forming cells (CFC) assay of human bone marrow mononuclear cells pre-treated with 100 nM SK-575 24 h before seeding them in MethoCult semi-solid methylcellulose-based media with the indicated doses of Talazoparib with or without 100 nM SK-575. Colonies were quantified after 14 days. Error bars indicate mean ± s.d. (n = 3). Statistical significance was determined with unpaired t-tests. In all the figures * = p < 0.05, and *** = p < 0.001.

Article Snippet: Cells were treated with the following compounds at the indicated doses: BRD4 PROTAC A1874 (HY-114305, MedChemExpress) at 1 μM; PARP1 PROTACs SK-575 (HY-139156, MedChemExpress) at 100 nM and 180055 (HY-170620, MedChemExpress) at 1 μM; and PARP inhibitors Talazoparib (HY-16106, MedChemExpress) and Olaparib (HY-10162, MedChemExpress) at concentrations ranging from 48 μM to 0.02 μM in 3-fold dilutions.

Techniques: Western Blot, Expressing, Control, Viability Assay, Staining, Flow Cytometry

Journal: bioRxiv

Article Title: PROTAC-Driven Protective Therapy increases the therapeutic window of anticancer drugs

doi: 10.64898/2026.01.12.698947

Figure Lengend Snippet: A) Structure of SK-575 PROTAC formed by the PARPi Olaparib linked to Thalidomide, a CRBN binder. B) Western blot analysis of PARP1 expression in isogenic CRBN WT and KO KBM7 cells treated with 100 nM SK-575 or Thalidomide for 48h. ACTB was used as loading control. C) Viability assay by MTT performed in CRBN WT or KO KBM7 cells pre-treated with 100 nM SK-575 for 24 h followed by a treatment with both SK-575 and the indicated doses of Olaparib or Talazoparib for another 24 h. Data are normalized to vehicle or SK-575 pre-treated cells and correspond to three biological replicates. IC50s were calculated with non-linear regression analysis and are shown in the figure (µM). Statistical significance was determined with Extra sum-of-squares F test. D) Analysis of percentage of viability as assessed by Annexin V/PI staining using flow cytometry analysis from three biological replicates. Statistical significance was determined with Ordinary one-way ANOVA and Tukey’s multiple comparisons test. E) Representative images of the Annexin V/PI staining. Percentage of cells for each population are shown. F) Western blot showing PARP1 degradation in human bone marrow mononuclear cells treated with 100 nM SK-575 for 48 h. G) Colony-forming cells (CFC) assay of human bone marrow mononuclear cells pre-treated with 100 nM SK-575 24 h before seeding them in MethoCult semi-solid methylcellulose-based media with the indicated doses of Talazoparib with or without 100 nM SK-575. Colonies were quantified after 14 days. Error bars indicate mean ± s.d. (n = 3). Statistical significance was determined with unpaired t-tests. In all the figures * = p < 0.05, and *** = p < 0.001.

Article Snippet: Cells were treated with the following compounds at the indicated doses: BRD4 PROTAC A1874 (HY-114305, MedChemExpress) at 1 μM; PARP1 PROTACs SK-575 (HY-139156, MedChemExpress) at 100 nM and 180055 (HY-170620, MedChemExpress) at 1 μM; and PARP inhibitors Talazoparib (HY-16106, MedChemExpress) and Olaparib (HY-10162, MedChemExpress) at concentrations ranging from 48 μM to 0.02 μM in 3-fold dilutions.

Techniques: Western Blot, Expressing, Control, Viability Assay, Staining, Flow Cytometry