Gongora, C. | Search bioRxiv

bioRxiv2023

The Hippo pathway terminal effector TAZ/WWTR1 mediates oxaliplatin sensitivity in HCT116 colon cancer cells

YAP and TAZ, the Hippo pathway terminal transcriptional activators, are frequently upregulated in cancers. In tumor cells, they have been mainly associated with increased tumorigenesis controlling different aspects from cell cycle regulation, stemness, or resistance to chemotherapies. In fewer cases, they have also been shown to oppose cancer progression, including by promoting cell death through the action of the P73/YAP transcriptional complex, in particular after chemotherapeutic drug exposure. Using several colorectal cancer cell lines, we show here that oxaliplatin treatment led to a dramatic core Hippo pathway down-regulation and nuclear accumulation of TAZ. We further show that TAZ was required for the increased sensitivity of HCT116 cells to oxaliplatin, an effect that appeared independent of P73, but which required the nuclear relocalization of TAZ. Accordingly, Verteporfin and CA3, two drugs affecting the activity of YAP and TAZ, showed an antagonistic with oxaliplatin in co-treatments. Our results support thus an early action of TAZ to sensitize cells to oxaliplatin, consistent with a model in which nuclear TAZ in the context of DNA damage and P53 activity pushes cells towards apoptosis.

cancer biology↗

bioRxiv2022

The crosstalk between DNA-PK and cGAS drives tumor immunogenicity

Cytosolic DNAs promote inflammatory responses upon detection by the cyclic GMP-AMP (cGAMP) synthase (cGAS). It has been thus suggested that cGAS downregulation is an immune escape strategy harnessed by tumor cells. Here, we used glioblastoma cells that lack cGAS to question whether alternative DNA detection pathways can promote pro-inflammatory signaling. We show that the DNA-PK DNA repair complex drives cGAS independent inflammatory responses but that its catalytic activity is required for cGAS-dependent cGAMP production and optimal downstream signaling. We further show that the cooperation between DNA-PK and cGAS favors the expression of chemokines that promote macrophage recruitment in the tumor microenvironment, a process that impaired early tumorigenesis but correlated with poor outcome. Thus, our study supports that cGAS-dependent signaling is acquired during tumorigenesis and that cGAS and DNA-PK activities should be analyzed concertedly to predict the impact of strategies aiming to boost tumor immunogenicity.

cancer biology↗