BUSCADOR RECOLECTA

Gene level data for Venn Diagram figure of Cell line screening data, DLBCL are aggressive, rapidly proliferating tumors that critically depend on the ATF4-mediated integrated stress response (ISR) to adapt to stress caused by uncontrolled growth, such as hypoxia, amino acid deprivation, and accumulation of misfolded proteins. Here, we show that ISR hyperactivation is a targetable liability in DLBCL. We describe a novel class of compounds represented by BTM-3528 and BTM-3566, which activate the ISR through the mitochondrial protease OMA1. Treatment of tumor cells with compound leads to OMA1-dependent cleavage of DELE1 and OPA1, mitochondrial fragmentation, activation of the eIF2α-kinase HRI, cell growth arrest, and apoptosis. Activation of OMA1 by BTM-3528 and BTM-3566 is mechanistically distinct from inhibitors of mitochondrial electron transport, as the compounds induce OMA1 activity in the absence of acute changes in respiration. We further identify the mitochondrial protein FAM210B as a negative regulator of BTM-3528 and BTM-3566 activity. Overexpression of FAM210B prevents both OMA1 activation and apoptosis. Notably, FAM210B expression is nearly absent in healthy germinal center B-lymphocytes and in derived B-cell malignancies, revealing a fundamental molecular vulnerability which is targeted by BTM compounds. Both compounds induce rapid apoptosis across diverse DLBCL lines derived from activated B-cell, germinal center B-cell, and MYC-rearranged lymphomas. Once-daily oral dosing of BTM-3566 resulted in complete regression of xenografted human DLBCL SU-DHL-10 cells and complete regression in 6 of 9 DLBCL patient-derived xenografts. BTM-3566 represents a first-of-its kind approach of selectively hyperactivating the mitochondrial ISR for treating DLBCL., Peer reviewed

Spearmans Rank correlation of gene expression with response to compound in the cell line screening data., DLBCL are aggressive, rapidly proliferating tumors that critically depend on the ATF4-mediated integrated stress response (ISR) to adapt to stress caused by uncontrolled growth, such as hypoxia, amino acid deprivation, and accumulation of misfolded proteins. Here, we show that ISR hyperactivation is a targetable liability in DLBCL. We describe a novel class of compounds represented by BTM-3528 and BTM-3566, which activate the ISR through the mitochondrial protease OMA1. Treatment of tumor cells with compound leads to OMA1-dependent cleavage of DELE1 and OPA1, mitochondrial fragmentation, activation of the eIF2α-kinase HRI, cell growth arrest, and apoptosis. Activation of OMA1 by BTM-3528 and BTM-3566 is mechanistically distinct from inhibitors of mitochondrial electron transport, as the compounds induce OMA1 activity in the absence of acute changes in respiration. We further identify the mitochondrial protein FAM210B as a negative regulator of BTM-3528 and BTM-3566 activity. Overexpression of FAM210B prevents both OMA1 activation and apoptosis. Notably, FAM210B expression is nearly absent in healthy germinal center B-lymphocytes and in derived B-cell malignancies, revealing a fundamental molecular vulnerability which is targeted by BTM compounds. Both compounds induce rapid apoptosis across diverse DLBCL lines derived from activated B-cell, germinal center B-cell, and MYC-rearranged lymphomas. Once-daily oral dosing of BTM-3566 resulted in complete regression of xenografted human DLBCL SU-DHL-10 cells and complete regression in 6 of 9 DLBCL patient-derived xenografts. BTM-3566 represents a first-of-its kind approach of selectively hyperactivating the mitochondrial ISR for treating DLBCL., Peer reviewed

The basement membrane (BM) is a specialized extracellular matrix (ECM), which underlies or encases developing tissues. Mechanical properties of encasing BMs have been shown to profoundly influence the shaping of associated tissues. Here, we use the migration of the border cells (BCs) of the Drosophila egg chamber to unravel a new role of encasing BMs in cell migration. BCs move between a group of cells, the nurse cells (NCs), that are enclosed by a monolayer of follicle cells (FCs), which is, in turn, surrounded by a BM, the follicle BM. We show that increasing or reducing the stiffness of the follicle BM, by altering laminins or type IV collagen levels, conversely affects BC migration speed and alters migration mode and dynamics. Follicle BM stiffness also controls pairwise NC and FC cortical tension. We propose that constraints imposed by the follicle BM influence NC and FC cortical tension, which, in turn, regulate BC migration. Encasing BMs emerge as key players in the regulation of collective cell migration during morphogenesis., Peer reviewed

1 file, Supporting information for article https://doi.org/10.1021/acsomega.3c10052, Peer reviewed

(A) Proposed model for the forces exerted over BCs as they migrate. (B–D) Schematic drawing showing the consequences of altering the forces exerted over BCs on their migration. BC, border cell; BM, basement membrane; FC, follicle cell; NC, nurse cell., Peer reviewed

(A) Schematic drawings of an S9 egg chamber illustrating the mirrorGal4 pattern of expression (mirrGal4, pink) and the point of ablation in the basal side of FCs (blue bar). NCs are in gray, BCs in yellow, FCs in purple, and BM in blue. (B) Images of life S9 control mirrGal4 and mirr>AbiRNAi egg chambers expressing Resille-GFP before and after FCs bonds are ablated. Blue bars indicate points of ablation. (C) Quantification of initial velocity of vertex displacement of the indicated ablated bonds. (D) Schematic drawing of an S9 egg chamber illustrating the mirrGal4 pattern of expression (pink) and the point of ablation in the NCs (blue bar). (E) Images of life S9 egg chambers of the indicated genotypes before and after NC bonds are ablated. Blue bars indicate points of ablation. (F) Quantification of initial velocity of vertex displacement of the indicated ablated bonds. (G–H’) Stills taken from live imaging of migrating BCs from egg chambers of the indicated genotypes. Discontinuous yellow lines demarcate the region between the anterior border of the egg chamber and the oocyte anterior membrane. (I, J) Quantification of BC migration speed in the area anterior to (I) and at the (J) mirr expressing region. The statistical significance of differences was assessed with a t test, * P value < 0.05, ** P value < 0.01, and *** P value < 0.001. Horizontal and vertical lines indicate mean and SD, respectively. Scale bar in B, E, and G–H’, 5 μm, 10 μm, and 20 μm, respectively. The raw data underlying panels C, F, I, and J are available in S1 Data. BC, border cell; BM, basement membrane; FC, follicle cell; GFP, green fluorescent protein; NC, nurse cell., Peer reviewed

(A–B”) Stills taken from live imaging of migrating BCs from egg chambers of the indicated genotypes. (C, D) Quantification of BC migration speed in egg chambers of the indicated genotypes in the area anterior to (C) and at the (D) mirr expressing region. (E) Quantification of egg chambers with complete BC migration. The statistical significance of differences was assessed with a t test, * P value < 0.05. Horizontal and vertical lines indicate mean and SD, respectively. Scale bars in A” and B”, 20 μm. The raw data underlying panels C–E are available in S1 Data. BC, border cell; FC, follicle cell., Peer reviewed

(A) Position of ovaries within a Drosophila female (left) and schematic of Drosophila ovaries showing an ovariole and its egg chambers (right). BC, border cells; Oo, oocyte; NCs, nurse cells; FCs, follicle cells; StFCs, stretch FCs; BM, basement membrane. (B) Diagram of an ovariole showing stages 8, 9, and 10 egg chambers (S8–S10). Anterior is left, posterior right. (C) Three-dimensional diagram of a S9 egg chamber showing the migration of the BCs between the NCs. (D–G’) Stills taken from live imaging of migrating BCs from egg chambers of the indicated genotypes. Discontinuous yellow lines demarcate the region between the anterior border of the egg chamber and the oocyte anterior membrane. (H–J) Quantification of BC migration speed during the whole migratory process (H) and during the early (I) and late (J) phases in egg chambers of the indicated genotypes. The statistical significance of differences was assessed with a t test, ** P value < 0.01. Horizontal and vertical lines indicate mean and SD, respectively. Scale bars in A’, B’, C’ and D’, 20 μm. The raw data underlying panels H–J are available in S1 Data., Peer reviewed

The basement membrane (BM) is a specialized extracellular matrix (ECM), which underlies or encases developing tissues. Mechanical properties of encasing BMs have been shown to profoundly influence the shaping of associated tissues. Here, we use the migration of the border cells (BCs) of the Drosophila egg chamber to unravel a new role of encasing BMs in cell migration. BCs move between a group of cells, the nurse cells (NCs), that are enclosed by a monolayer of follicle cells (FCs), which is, in turn, surrounded by a BM, the follicle BM. We show that increasing or reducing the stiffness of the follicle BM, by altering laminins or type IV collagen levels, conversely affects BC migration speed and alters migration mode and dynamics. Follicle BM stiffness also controls pairwise NC and FC cortical tension. We propose that constraints imposed by the follicle BM influence NC and FC cortical tension, which, in turn, regulate BC migration. Encasing BMs emerge as key players in the regulation of collective cell migration during morphogenesis., Peer reviewed

(A–B’) Stills taken from live imaging of migrating BCs from egg chambers of the indicated genotypes. (C) Quantification of the migration defects in egg chambers of the specified genotypes. The statistical significance of differences was assessed with a t test, *** P value < 0.001. Horizontal and vertical lines indicate mean and SD, respectively. Scale bars in A’ and B’, 20 μm. The raw data underlying panel C are available in S1 Data., Peer reviewed