Biology subjects

Pass, I.

Publications and source records attributed to Pass, I..

5 recordsLinked to original sources

bioRxiv2026

Small-molecule modulators of HIPK4 activity and proteostasis

Homeodomain-interacting protein kinase 4 (HIPK4) is a dual-specificity kinase that is predominantly expressed in differentiating spermatids, required for sperm development, and a promising target for nonhormonal male contraception. Genetic and functional studies have established an essential role for HIPK4 in spermiogenesis, where it acts at least in part through regulation of the F-actin-scaffolded acroplaxome during spermatid head shaping. The direct molecular targets of HIPK4 and their downstream effectors remain poorly defined, and small-molecule probes would be versatile tools for further investigating HIPK4 functions. Synthetic HIPK4 ligands could also be valuable leads for the development of nonhormonal male contraceptives. Here, we report the discovery of a cyanoquinoline-based series of HIPK4 inhibitors with nanomolar potency. Our lead compounds are selective for HIPK4, both within the HIPK family and across the broader kinome, establishing this scaffold as a useful starting point for probe and lead development. Unexpectedly, we found that a subset of these cyanoquinolines also perturbs HIPK4 proteostasis in a cell type-specific manner. In spermatids, these compounds induce the formation of detergent-insoluble HIPK4 aggregates and promote interactions between this kinase and the autophagy receptor Tax1-binding protein 1 (TAX1BP1). Together, our findings establish cyanoquinoline ligands as a new chemotype for probing HIPK4 biology and advancing male contraceptive discovery.

biochemistry↗

bioRxiv2024

Targeting eIF4G1-dependent translation in melanoma

Expression of components of the translation initiation complex (eIF4F) is frequently elevated in cancer, resulting in enhanced synthesis of oncogenic proteins. We thus set out to limit eIF4F pro-oncogenic activity, a notable challenge given its essential role in normal tissues. CRISPR-Cas9-based functional screen using tiling sgRNAs identified the eIF4G1 MA3 domain, a subunit of the eIF4F complex, as a target for developing small molecule inhibitors. Combination of structure-guided in silico modeling and chemical library screening led to the identification of small molecule candidates M19 and its analog M19-6 that binds to the MA3 domain of eIF4G1 and disrupts eIF4F complex. M19-6 treatment reprograms the melanoma translatome, limiting synthesis of factors that promote cell proliferation and neoplastic growth, as well as reducing translation of mRNAs encoding ferroptosis suppressors. Whole genome CRISPR screen indentified ferroptosis activators to augment M19-6 activity, which was confirmed in cultured melanoma cells. M19-6 alleviates melanoma resistance to BRAF and MEK inhibitors, while eliciting anti-tumor and anti-metastatic effects in preclinical mouse models. Among several biomarkers found in M19-6 sensitive cell lines, THBS1 and TGF{beta}I expression were elevated in patients who are non-responders to PD-1 therapy as in patients with metastasis. Our studies identify M19-6 as a therapeutic candidate, offering a novel insights into targeting the eIF4F complex to overcome melanoma resistance to therapy and metastasis. SignificanceWe identify M19-6 as a small molecule that disrupts the eIF4F, translation initiation complex, by targeting the MA3 domain of eIF4G1, resulting in elimination of melanoma cells in culture, overcoming therapy resistance while inhibiting melanoma growth and metastasis in vivo. As M19-6 causes minimal toxicity to melanocytes, it offers a therapeutic modality for melanoma.

cancer biology↗

bioRxiv2020

RNF5 Regulation of RBBP4 Defines Acute Myeloid Leukemia Growth and Susceptibility to Histone Deacetylase Inhibitors

Acute myeloid leukemia (AML) remains incurable, largely due to its resistance to conventional treatments. Here, we found that increased expression and abundance of the ubiquitin ligase RNF5 contributes to AML development and survival. High RNF5 expression in AML patients correlated with poor prognosis. RNF5 inhibition decreased AML cell growth in culture and in vivo, and blocked development of MLL-AF9-driven leukemogenesis in mice, prolonging their survival. RNF5 inhibition led to transcriptional changes that overlapped with those seen upon HDAC1 inhibition. RNF5 induced the formation of K29 ubiquitin chains on the histone-binding protein RBBP4, promoting its recruitment and subsequent epigenetic regulation of genes involved in AML development and maintenance. Correspondingly, RNF5 or RBBP4 knockdown enhanced the sensitivity of AML cells to histone deacetylase (HDAC) inhibitors. Notably, low expression of RNF5 and HDAC coincided with a favorable prognosis. Our studies identified ERAD-independent role for RNF5, demonstrating that its control of RBBP4 constitutes an epigenetic pathway that drives AML while highlighting RNF5/RBBP4 as markers to stratify patients for treatment with HDAC inhibitors.

cancer biology↗

bioRxiv2020

The serine-threonine kinase TAO3 promotes cancer invasion and tumor growth by facilitating trafficking of endosomes containing the invadopodia scaffold TKS5α

Invadopodia are actin-based proteolytic membrane protrusions required for invasive behavior and tumor growth. We used our high-content screening assay to identify kinases impacting invadopodia formation. Among the top hits we selected TAO3, a STE20-like kinase of the GCK subfamily, for further analysis. TAO3 was over-expressed in many human cancers, and regulated invadopodia formation in melanoma, breast and bladder cancers. Furthermore, TAO3 catalytic activity facilitated melanoma growth in 3-dimensional matrices and in vivo. We developed potent catalytic inhibitors of TAO3 that inhibited invadopodia formation and function, and tumor cell extravasation and growth. Using these inhibitors, we determined that TAO3 activity was required for endosomal trafficking of TKS5, an obligate invadopodia scaffold protein. A phosphoproteomics screen for TAO3 substrates revealed the dynein subunit protein LIC2 as a relevant substrate. Knockdown of LIC2 or expression of a phosphomimetic form promoted invadopodia formation. Thus, TAO3 is a new therapeutic target with a distinct mechanism of action. SIGNIFICANCETargeting tumor invasive behavior represents an understudied opportunity. We used an unbiased screening approach to identify kinases required for invadopodia formation and function. We validated TAO3, both genetically and with a novel inhibitor, and determined TAO3 function. Our data support clinical development of this class of target.

cancer biology↗

bioRxiv2019

Improving drug discovery using image-based multiparametric analysis of epigenetic landscape.

With the advent of automatic cell imaging and machine learning, high-content phenotypic screening has become the approach of choice for drug discovery due to its ability to extract drug specific multilayered data and compare it to known profiles. In the field of epigenetics such screening approaches has suffered from the lack of tools sensitive to selective epigenetic perturbations. Here we describe a novel approach Microscopic Imaging of Epigenetic Landscapes (MIEL) that captures patterns of nuclear staining of epigenetic marks (e.g. acetylated and methylated histones) and employs machine learning to accurately distinguish between such patterns (1). We demonstrated that MIEL has superior resolution compared to conventional intensity thresholding techniques and enables efficient detection of epigenetically active compounds, function-based classification, flagging possible off-target effects and even predict novel drug function. We validated MIEL platform across multiple cells lines and using dose-response curves to insure the robustness of this approach for the high content high throughput drug discovery.

cell biology↗