Biology subjects

Salhotra, S.

Publications and source records attributed to Salhotra, S..

4 recordsLinked to original sources

bioRxiv2026

Generation and characterization of human iPSC-derived NPC1I1061T/I10161T i3Neurons as a model for NPC1 disease

Niemann-Pick disease, type C is an autosomal recessive, fatal, neurodegenerative disorder caused by pathological variants in NPC1 or NPC2. Dysfunction of either NPC1 or NPC2 results in impaired intracellular cholesterol transport and subsequent storage of unesterified cholesterol in endolysosomal compartments. Earlier cell-based studies utilized patient fibroblasts to study this disease; however, neuronal cells allow for investigation of the neurodegenerative aspect of NPC1. Expression of neurogenin in induced pluripotent stem cells leads to the generation of i3Neurons (integrated, isogenic, and inducible), allowing for rapid, synchronized growth of homogenous neurons. In this study, we report the development and characterization of a human iPSC-derived NPC1I1061T/I1061Ti3Neuronal model system. NPC1I1061Tis a missense variant resulting in a misfolded protein targeted for proteasomal degradation in the ER. NPC1I1061T/I1061T i3Neurons phenocopied the cellular pathological features of NPC1 disease including endolysosomal cholesterol accumulation, lysosomal morphological changes, and response to the proteostasis modulator, mo56HC. The NPC1 phenotype was alleviated by 2-hydroxypropyl-{beta}-cyclodextrin treatment, a drug demonstrating efficacy both in vitro and in vivo. This NPC1I1061T/I1061T i3Neuronal cell line can facilitate future high-throughput drug and genomic screens, particularly those aimed at identifying proteostasis regulators that improve the expression/stability of the mutant NPC1 protein.

neuroscience↗

bioRxiv2025

Chromatin Perturbation Promotes Susceptibility to Hypomethylating Agents

Cancer-directed drugs are often clinically deployed without definitive understanding of their molecular mechanisms of action (MOA). Hypomethylating agents (HMAs), which result in the degradation of the DNA methyltransferase 1 (DNMT1), have been deployed for decades in the treatment of haematological malignancies1,2. The precise mechanism of action of these drugs, however, has been debated, rendering the design of rational combination therapies challenging. Here, we identified the deubiquitinating enzyme USP48 as a crucial regulator of posttranslational histone modification in the context of DNA demethylation. USP48 loss selectively enhances response to DNMT1 inhibition, leading to a rapid induction of cell death. We demonstrate that USP48 is localized at sites of DNA damage and deubiquitinates H2A variants and proteins important for DNA damage repair. Functionally, loss of USP48 triggers an increase in chromatin accessibility upon HMA treatment, rendering AML cells more susceptible to DNA damage. Our results support USP48 as a posttranslational histone modifier for chromatin stability and DNA damage in response to HMA-related DNA demethylation. These findings propose USP48 as a new target for combination therapy with HMAs for acute myeloid leukaemia (AML).

cancer biology↗

bioRxiv2025

KAT6A/B inhibition synergizes with retinoic acid and enhances the efficacy of GD2-targeted immunotherapy in neuroblastoma

High-risk neuroblastoma accounts for about 15% of childhood cancer deaths and arises from precursors of the peripheral sympathetic nervous system. Retinoids are clinically used to inhibit growth of neuroblastoma cells through reconfiguration of the regulatory enhancer landscape. Its effects, however, are completely reversible after drug withdrawal, leading to rapid tumor cell proliferation. Here, we sought to identify epigenetic modifiers that potentiate the antiproliferative effects of retinoids in neuroblastoma. We identified PF-9363, an inhibitor of the histone H3K23 acetyltransferases KAT6A/B, as synergistically inhibiting neuroblastoma growth in combination with retinoids. PF-9363 plus retinoids induces durable growth arrest, which persists beyond retinoid withdrawal in vitro and in vivo with sustained Polycomb-mediated repression of oncogenic transcription factors MYCN, PHOX2B and GATA3. Moreover, PF-9363 plus retinoids increases GD2 expression, rendering neuroblastoma cells more sensitive to anti-GD2 immunotherapy. Overall, our studies demonstrate that KAT6A/B inhibition increases the effectiveness of retinoids and GD2-targeted immunotherapy in neuroblastoma.

cancer biology↗

bioRxiv2025

Riboflavin drives nucleotide biosynthesis and iron-sulfur metabolism to promote acute myeloid leukemia

Riboflavin is a diet-derived vitamin in higher organisms that serves as a precursor for flavin mononucleotide and flavin adenine dinucleotide, key cofactors that participate in oxidoreductase reactions. Here, using proteomic, metabolomic and functional genomics approaches, we describe a specific riboflavin dependency in acute myeloid leukemia and demonstrate that, in addition to energy production via oxidative phosphorylation, a key biological role of riboflavin is to enable nucleotide biosynthesis and iron-sulfur cluster metabolism. Genetic perturbation of riboflavin metabolism pathways or exogenous depletion in physiological culture medium induce nucleotide imbalance and DNA damage responses, as well as impair the stability and activity of proteins which utilize [4Fe-4S] iron-sulfur clusters as cofactors. We identify a window of therapeutic opportunity upon riboflavin starvation or chemical riboflavin metabolism perturbation and demonstrate that this strongly synergizes with BCL-2 inhibition. Our work identifies riboflavin as a critical metabolic dependency in leukemia, with functions beyond energy production.

cancer biology↗