Biology subjects

Attolini, C. S.-O.

Publications and source records attributed to Attolini, C. S.-O..

3 recordsLinked to original sources

bioRxiv2023

Membrane to cortex attachment determines different mechanical phenotypes in LGR5+ and LGR5- colorectal cancer cells

Colorectal cancer tumors are composed of heterogeneous and plastic cell populations, including a pool of cancer stem cells that express LGR5. Whether these distinct cell populations display different mechanical properties, and how these properties might contribute to metastasis is unknown. Using CRC patient derived organoids (PDOs), we found that compared to LGR5- cells, LGR5+ cancer stem cells are stiffer, adhere better to the extracellular matrix (ECM), move slower both as single cells and clusters, display higher nuclear YAP, show a higher survival rate in response to mechanical confinement, and form larger transendothelial gaps. These differences are largely explained by the downregulation of the membrane to cortex attachment proteins Ezrin/Radixin/Moesin (ERMs) in the LGR5+ cells. By analyzing scRNA-seq expression patterns from a patient cohort, we show that this downregulation is a robust signature of colorectal tumors. Our results show that LGR5- cells display a mechanically dynamic phenotype suitable for dissemination from the primary tumor whereas LGR5+ cells display a mechanically stable and resilient phenotype suitable for extravasation and metastatic growth.

cancer biology↗

bioRxiv2022

The efficacy of chemotherapy is limited by intratumoural senescent cells that persist through the upregulation of PD-L2

Anti-cancer therapies often result in a subset of surviving cancer cells that undergo therapy-induced senescence (TIS). Senescent cancer cells strongly modify the intratumoural microenvironment favoring immunosuppression and, thereby, tumour growth. An emerging strategy to optimise current therapies is to combine them with treatments that eliminate senescent cells. To this end, we undertook an unbiased proteomics approach to identify surface markers contributing to senescent cells immune evasion. Through this approach, we discovered that the immune checkpoint inhibitor PD-L2, but not PD-L1, is upregulated across multiple senescent human and murine cells. Importantly, blockade of PD-L2 strongly synergises with genotoxic chemotherapy, causing remission of solid tumours in mice. We show that PD-L2 inhibition prevents the persistence of chemotherapy-induced senescent cells, which exert cell-extrinsic immunomodulatory actions. In particular, upon chemotherapy, tumours deficient in PD-L2 fail to produce cytokines of the CXCL family, do not recruit myeloid-derived suppressor cells (MDSCs) and are eliminated in a CD8 T cell-dependent manner. We conclude that blockade of PD-L2 improves chemotherapy efficacy by reducing the intratumoural burden of senescent cells and their associated recruitment of immunosuppressive cells. These findings provide a novel strategy to exploit vulnerabilities arising in tumour cells as a result of therapy-induced damage and cellular senescence.

cancer biology↗

bioRxiv2019

Tousled-like kinase activity is required for transcriptional silencing and suppression of innate immune signaling

The Tousled like kinases 1 and 2 (TLK1/2) control histone deposition through the ASF1 histone chaperones and are regulated by the DNA damage response. Depletion of TLK activity caused replication stress, increased chromosomal instability and cell arrest or death. Here, we show that stalled forks in TLK depleted cells are processed by BLM, SAMHD1 and the MRE11 nuclease to generate ssDNA and activate checkpoint signaling. TLK depletion also impaired heterochromatin maintenance, inducing features of alternative lengthening of telomeres and increasing spurious expression of other repetitive elements, associated with impaired deposition of the histone variant H3.3. TLK depletion culminated in a BLM-dependent, STING-mediated innate immune response. In many human cancers, TLK1/2 expression correlated with signatures of chromosomal instability and anti-correlated with STING and innate and adaptive immune response signatures. Together, our results show that TLK activity protects replication forks from active processing, contributes to chromatin silencing and suppresses innate immune responses, suggesting that TLK amplification may protect chromosomally unstable cancers from immune detection.

molecular biology↗