Biology subjects

Presser, A.

Publications and source records attributed to Presser, A..

4 recordsLinked to original sources

bioRxiv2026

A peptide-based screen for cell death inhibitors identifies the cytoprotective compound CDL36

Small molecule inhibitors of cell death have wide-ranging potential applications, both as tool compounds in the laboratory and as clinical modulators of pathologic cell death. Previous screening efforts have identified candidate compounds targeting the pro-apoptotic, pore-forming BCL-2 family proteins BAX and BAK, but the complex interactions of these proteins at the mitochondrial outer membrane (with other proteins and the membrane itself) present challenges for compound screening. Although no inhibitors of BAX or BAK have advanced to clinical testing to date, candidate inhibitors have thus far been identified via screening of membrane-containing systems such as liposomes and isolated mitochondria. To address some of the challenges of chemical screening for apoptosis inhibitors, we conducted a small molecule screen utilizing BH3 profiling, a method that quantifies mitochondrial outer membrane permeabilization (MOMP) upon treatment with pro-apoptotic peptides derived from BCL-2 family proteins. Of over 40,000 compounds screened, we identified a series of compounds that prevent MOMP in response to pro-apoptotic peptides. The most potent of these, CDL36, binds to BAX and prevents MOMP at early timepoints. In longer term viability assays, the cytoprotective effect of CDL36 is most potent against death induced by doxorubicin, a widely used chemotherapeutic agent that causes dose-limiting cardiovascular toxicity. Our results elucidate the mechanism of action of new and existing cell death inhibitors, providing a foundation for further development of these inhibitors and potential insights into the mechanisms mediating doxorubicin toxicity in patients.

molecular biology↗

bioRxiv2025

Paclitaxel-induced mitotic arrest results in a convergence of apoptotic dependencies that can be safely exploited by BCL-XL degradation to overcome cancer chemoresistance

Paclitaxel and other microtubule-targeting agents are cornerstone therapies for diverse cancers, including lung, breast, cervical, pancreatic, and ovarian malignancies. Paclitaxel induces tumor cell apoptosis during mitosis by disrupting microtubule dynamics required for chromosome segregation. However, despite initial responsiveness, many tumors develop resistance, limiting therapeutic durability. Here, we used high-grade serous ovarian carcinoma (HGSOC), the most common and lethal subtype of ovarian cancer, as a model to dissect the mechanisms underlying this resistance. We find that paclitaxel-induced mitotic arrest triggers degradation of the pro-survival protein MCL-1 and upregulation of BCL-XL, followed by inactivating phosphorylation of BCL-XL at Ser62 to promote apoptosis. In resistant cells, this MCL-1 downregulation is insufficient to commit cells to apoptosis but instead results in a transient convergence of apoptotic dependencies by forcing BCL-XL to sequester the pro-apoptotic proteins BIM, BAX, and BAK. During this state, BCL-XL inhibition induces synergistic apoptosis, even in chemoresistant cells. Surprisingly, we also discover that loss of substrate attachment recapitulates this apoptotic convergence both in vitro and in vivo, with HGSOC cells growing in metastasis-promoting malignant ascites displaying heightened apoptotic priming and dependence on BCL-XL relative to solid tumors. In HGSOC xenografts, targeted degradation of BCL-XL using the platelet-sparing proteolysis-targeting chimera (PROTAC) DT2216 matches the efficacy of paclitaxel monotherapy while avoiding the chronic thrombocytopenia induced by BCL-XL inhibitors such as navitoclax (ABT-263). Strikingly, combination therapy leveraging the synergy between paclitaxel and DT2216 leads to complete eradication of HGSOC cell line and patient-derived xenografts. Moreover, DT2216 treatment blunts the rapid apoptotic adaptation caused by other BCL-XL inhibitors, indicating that targeted degradation of pro-survival proteins may yield more durable responses than inhibition alone. These findings uncover a mechanistic framework for safely exploiting the apoptotic dependency convergence caused by mitotic arrest and substrate detachment and support the clinical development of BCL-XL-targeting PROTACs to overcome chemoresistance in ovarian cancer and other solid tumors.

cancer biology↗

bioRxiv2023

Scabrous is distributed via signaling filopodia to modulate Notch response during bristle patterning in Drosophila

During development, tissues must be patterned correctly in order to support tissue function and shape. The sensory bristles of the peripheral nervous system on the thorax of Drosophila melanogaster self-organize from an unpatterned epithelial tissue to a regular spot pattern during pupal stages. Wild type patterning requires Notch-mediated lateral inhibition. Scabrous is a protein that can bind to and modify Notch receptor activity. Scabrous can be secreted, but it is also known to be localized to basal signaling filopodia, or cytonemes, that play a role in long-range Notch signaling. Consistent with previous work, we show that Scabrous is primarily distributed basally, within the range of signaling filopodia extension. We show that signaling filopodia are required for the distribution of Scabrous protein during sensory bristle patterning stages. We show that the Notch response of epithelial cells is sensitive to the level of Scabrous protein being expressed by the sensory bristle precursor cell. Our findings at the cell-level suggest a model for how epithelial cells engaged in lateral inhibition at a distance are sensitive local levels of Scabrous protein.

developmental biology↗

bioRxiv2019

Clonal plasma cells in AL amyloidosis are dependent on pro survival BCL-2 family proteins and sensitive to BH3 mimetics

Immunoglobulin light chain (AL) amyloidosis is a protein misfolding disorder characterized by the production of amyloidogenic immunoglobulin light chains by clonal populations of plasma cells. These abnormal light chains misfold and accumulate as amyloid fibrils in healthy tissues causing devastating multi-organ dysfunction that is rapidly fatal. Current treatment regimens, which include proteasome inhibitors, alkylating agents, and immunomodulatory agents, were developed for the treatment of the more common plasma cell disease, multiple myeloma, and have limited efficacy in AL amyloidosis as demonstrated by the median survival of 2-3 years. The recent development of novel small-molecule inhibitors of the major pro-survival proteins from the apoptosis-regulating BCL-2 family has created an opportunity to therapeutically target abnormal cell populations, yet identifying the extent of these dependencies and how to target them clinically has thus far been challenging. Using bone marrow-derived plasma cells from 45 patients with AL amyloidosis, we find that clonal plasma cells are highly primed to undergo apoptosis and exhibit strong dependencies on pro-survival BCL-2 family proteins. Specifically, we find that clonal plasma cells in a majority of patients are highly dependent on the pro-survival protein MCL-1 and undergo apoptosis when treated with an MCL-1 inhibitor as a single agent. In addition, BCL-2 inhibition sensitizes clonal plasma cells to several current standard of care therapies. Our results suggest that BH3 mimetics, when deployed rationally, may be highly effective therapies for AL amyloidosis.

cancer biology↗