Journal: bioRxiv

Article Title: Retroelement decay by the exonuclease XRN1 is a viral mimicry dependency in cancer

doi: 10.1101/2023.03.30.531699

Figure Lengend Snippet: dsRNA induced by Palbociclib or 5-AZA-CdR produces a synthetic dependency to XRN1 in XRN1-resistant POP92 cells. (A) Dot blot for dsRNA using total RNA from indicated cell lines. Normalized amounts of total RNA were dotted on Hybond N+ membranes, visualized by methylene blue staining, and immunoblotted with J2 antibody. (B) Representative confocal microscopy images of colorectal cell lines. Nuclei were stained with DAPI (blue) and dsRNA was stained using the J2 antibody (red). (C) Representative confocal microscopy images from control and knockout of XRN1 of POP92 cells treated with PBS or 5-AZA-CdR. Nuclei were stained with DAPI (blue) and dsRNA was stained using the J2 antibody (red). (D) Survival of wild-type XRN1 (black) and XRN1 knockout (red) patient-derived CRC cells (POP92) after treatment with 5-AZA-CdR. Luminescence signal was normalized, and dose-response curves and EC50 values were calculated using a nonlinear regression curve fit. (E) Survival of wild-type XRN1 (black) and XRN1-knockout (red) POP92 cells after treatment with palbociclib. Luminescent signal was normalized, and dose-response curves and EC50 values were calculated using a nonlinear regression curve fit.

Article Snippet: Palbociclib isethionate (HY-A0065) was purchased from Med Chem Express.

Techniques: Dot Blot, Staining, Confocal Microscopy, Control, Knock-Out, Derivative Assay

Journal: bioRxiv

Article Title: Retroelement decay by the exonuclease XRN1 is a viral mimicry dependency in cancer

doi: 10.1101/2023.03.30.531699

Figure Lengend Snippet: Proposed mechanism for XRN1 dependent viral mimicry adaptation. A) XRN1 resistant cell lines have low levels of immunogenic dsRNA and are therefore not relying on XRN1 to resist viral mimicry induced cell death. XRN1 sensitive cell lines require XRN1 to resist high levels of immunogenic dsRNA to induce viral mimicry induced cell death. Viral mimicry inducing drugs such as 5-AZA-CdR and palbociclib can generate a synthetic dependency to XRN1. B) XRN1 degrades dsRNA while ADAR1 edits A-to-I in dsRNA, these mechanisms have different effects on activation of MDA5 and PKR pathways. When ADAR1 and XRN1 are not present, both MDA5 and PKR can bind dsRNA and activate viral mimicry. If XRN1 is knocked out and only ADAR1 is present, the edited dsRNA will not activate the MDA5 pathway while the PKR pathway can still be activated. If both XRN1 and ADAR1 is present, dsRNA is both edited and degraded which hinders activation of MDA5 and PKR pathways.

Article Snippet: Palbociclib isethionate (HY-A0065) was purchased from Med Chem Express.

Techniques: Activation Assay

Journal: Molecular cell

Article Title: Cyclin D-Cdk4,6 Drives Cell-Cycle Progression via the Retinoblastoma Protein’s C-Terminal Helix

doi: 10.1016/j.molcel.2019.03.020

Figure Lengend Snippet: KEY RESOURCES TABLE

Article Snippet: Palbociclib , Santa Cruz Biotechnology , Cat#sc-478943.

Techniques: Purification, Produced, Virus, Recombinant, Selection, Membrane, Flow Cytometry, Expressing, Plasmid Preparation, Generated