Biology subjects

Aguirre-Ghiso, J.

Publications and source records attributed to Aguirre-Ghiso, J..

3 recordsLinked to original sources

bioRxiv2026

ARHGAP20 organizes spatial Rap1-RhoA signaling coordination controlling adhesion dynamics during migration

Cell migration requires the precise coordination of signaling pathways that regulate cytoskeletal dynamics and adhesion turnover. Rho GTPase-activating proteins (RhoGAPs) play critical roles in shaping these processes by controlling the spatial and temporal activity of small GTPases. ARHGAP20 is a RhoA-specific GAP, a downstream target of the Ras-related GTPase Rap1, and has been implicated in cancer cell motility, yet its functional role in coordinating migration-associated signaling remains poorly understood. Here, we investigated the role of ARHGAP20 in cell migration and its impact on the coordination between adhesion- and contractility-associated signaling pathways regulated by Rap1A and RhoA respectively. Using loss-of-function approaches in MTLn3 cells, we show that depletion of ARHGAP20 impairs both directed and random migration, leading to reduced cell velocity and displacement, and increased cell adhesion. To explore the underlying signaling mechanisms, we developed a genetically encoded FRET biosensor to monitor Rap1A activity and combined it with a near-infrared RhoA biosensor to simultaneously analyze their spatiotemporal dynamics in living cells. We found that Rap1A and RhoA activities are negatively coordinated during leading-edge dynamics and that ARHGAP20 depletion enhances this local anticorrelation. To further define where ARHGAP20 regulates Rap1A-RhoA signaling, we applied a microdomain-based analytical framework to quantify local signaling clusters. This analysis revealed that ARHGAP20 selectively modulates Rap1A-RhoA coordination outside focal adhesion regions, while leaving signaling correlations and overlap within focal adhesions unchanged. Subcellular localization analyses further reveal that ARHGAP20 is largely excluded from focal adhesions but associates with microtubules, the endoplasmic reticulum, the Golgi apparatus, and multiple Rab-positive vesicular compartments, supporting a trafficking-dependent mechanism for its spatial targeting. Together, our results identify ARHGAP20 as a regulator of cell migration that modulates the coordination between Rap1A and RhoA signaling through intracellular vesicular trafficking, highlighting the GAPs role in organizing the spatial coupling between signaling pathways in adhesion-associated regions required for efficient cell migration.

cell biology↗

bioRxiv2025

Quiescent OXPHOS-high triple-negative breast cancer cells that persist after chemotherapy depend on BCL-XL for survival

The persistent residual tumor cells that survive after chemotherapy are a major cause of treatment failure, but their survival mechanisms remain largely elusive. These cancer cells are typically characterized by a quiescent state with suppressed activity of MYC and MTOR. We observed that the MYC-suppressed persistent triple-negative breast cancer (TNBC) cells are metabolically flexible and can upregulate mitochondrial oxidative phosphorylation (OXPHOS) genes and respiratory function ("OXPHOS-high" cell state) in response to DNA-damaging anthracyclines such as doxorubicin, but not to taxanes. The elevated biomass and respiratory function of mitochondria in OXPHOS-high persistent cancer cells were associated with mitochondrial elongation and remodeling suggestive of increased mitochondrial fusion. A genome-wide CRISPR editing screen in doxorubicin-persistent OXPHOS-high TNBC cells revealed BCL-XL gene as the top survival dependency in these quiescent tumor cells, but not in their untreated proliferating counterparts. Quiescent OXPHOS-high TNBC cells were highly sensitive to BCL-XL inhibitors, but not to inhibitors of BCL2 and MCL1. Interestingly, inhibition of BCL-XL in doxorubicin-persistent OXPHOS-high TNBC cells rapidly abrogated mitochondrial elongation and respiratory function, followed by caspase 3/7 activation and cell death. The platelet-sparing proteolysis targeted chimera (PROTAC) BCL-XL degrader DT2216 enhanced the efficacy of doxorubicin against TNBC xenografts in vivo without induction of thrombocytopenia that is often observed with the first-generation BCL-XL inhibitors, supporting the development of this combinatorial treatment strategy for eliminating dormant tumor cells that persist after treatment with anthracycline-based chemotherapy.

cancer biology↗

bioRxiv2024

Lineage commitment pathways epigenetically oppose oncogenic Gαq/11-YAP signaling in dormant disseminated uveal melanoma

Uveal melanoma (UM) can remain in clinical dormancy for decades only to later produce lethal metastases. Using Gq/11mut/BAP1wt UM xenograft models and human metastatic samples, we identified NR2F1 as a key inducer of UM disseminated cancer cell (DCC) dormancy. Dormant UM DCCs upregulate NR2F1, neural crest genes and, along with suppression of proliferation programs, NR2F1 silences YAP1/TEAD1 transcription by altering histone H3 activation marks. YAP1 can reciprocally repress NR2F1, but inhibiting Gq/11 signaling or activating NR2F1 can arrest UM growth. NR2F1 knockout led to dormant DCC awakening and liver metastatic growth. NR2F1 and YAP1 inverse expression was confirmed in human livers carrying UM solitary, small DCC clusters as well as large metastases. Intriguingly, RNA-seq and Cut&Run analysis revealed that NR2F1 short-circuits oncogene signaling by repressing multiple G-protein signaling components. Our work provides previously unrecognized mechanistic insight into UM DCC dormancy and potential pathways for interception. Statement of significanceNR2F1 epigenetically suppresses genes associated with G-protein signaling, cell cycle, and YAP1/TEAD1 pathways, inducing dormancy in uveal melanoma (UM) disseminated cancer cells. This study unveils novel markers for UM dormancy and reactivation, positioning NR2F1 as a promising target for intercepting residual and UM metastatic disease.

cancer biology↗