Nuclear deformability increases PARPi sensitivity in BRCA1-deficient cells by increasing microtubule-dependent DNA break mobility.

Microtubules and nuclear transmembrane SUN1/2 proteins promote the mobility of DNA Double Strand Breaks (DSBs) induced by ionizing radiation and the misrepair of one-ended DSBs induced in BRCA1-deficient cells by Poly(ADP-ribose) polymerase inhibitors (PARPi). However, whether microtubules promote aberrant DSBs repair by altering the nuclear structure and whether the nuclear structure itself plays a role in these processes is still unclear. Here we show that microtubule-dependent DSBs mobility in BRCA1-deficient cells after PARPi treatment is associated with nuclear envelope (NE) invaginations.

Chromosome end protection by RAP1-mediated inhibition of DNA-PK.

During classical non-homologous end joining (cNHEJ), DNA-dependent protein kinase (DNA-PK) encapsulates free DNA ends, forming a recruitment platform for downstream end-joining factors including ligase 4 (LIG4). DNA-PK can also bind telomeres and regulate their resection, but does not initiate cNHEJ at this position. How the end-joining process is regulated in this context-specific manner is currently unclear.

A Novel G-Quadruplex Structure within Apolipoprotein E Promoter: A New Promising Target in Cancer and Dementia Fight?

Human apolipoprotein E (APOE) is a crucial lipid transport glycoprotein involved in various biological processes, including lipid metabolism, immune response, and neurodegeneration. Elevated APOE levels are linked to poor prognosis in several cancers and increased risk of Alzheimer's disease (AD). Therefore, modulating APOE expression presents a promising therapeutic strategy for both cancer and AD.

BRCA2 Deletion Induces Alternative Lengthening of Telomeres in Telomerase Positive Colon Cancer Cells.

BRCA1/2 are tumor suppressor genes controlling genomic stability also at telomeric and subtelomeric loci. Their mutation confers a predisposition to different human cancers but also sensitivity to antitumor drugs including poly(ADP-ribose) polymerase (PARP) inhibitors and G-quadruplex stabilizers. Here we demonstrate that BRCA2 deletion triggers TERRA hyperexpression and alternative lengthening mechanisms (ALT) in colon cancer cells in presence of telomerase activity.