Biology subjects

Jaiswar, A.

Publications and source records attributed to Jaiswar, A..

5 recordsLinked to original sources

bioRxiv2026

CAMOR and specific oncogene-driven lncRNAs mediate carcinogenic functions downstream of MYC, mutant KRAS, and mutant TP53

Purpose Long non-coding RNAs (lncRNAs) are important regulators of tumor biology, but their dependence on major oncogenic drivers and cancer specificity remain poorly characterized. We aimed to identify lncRNAs regulated by MYC, mutant KRAS, and mutant TP53 across colorectal, lung, and pancreatic cancer and to determine their functional relevance and molecular mechanism. Methods We performed an integrative analysis of lncRNA expression profiles driven by MYC, mutant KRAS, and mutant TP53 across colorectal, lung, and pancreatic cancer cell lines. Candidate lncRNAs were functionally characterized using assays of cancer cell viability, migration, and clonogenicity. Expression in patient-derived tumor and normal tissues and downstream molecular pathways were investigated. Results MYC was associated with the most extensive lncRNA regulation, with expression patterns largely independent of tissue origin. MYC-dependent LINC00997 and the previously uncharacterized AC104447.1, as well as specifically KRAS-dependent RAKRAR (RASSF3 antisense KRAS regulated lncRNA) promoted cancer cell viability, migration, and clonogenicity. LINC00997 and AC104447.1 expression was elevated in specific tumor types compared to normal tissues. We identified CAMOR (CARNMT1 Antisense Multiple-Oncoprotein Regulated lncRNA), a pan-cancer lncRNA upregulated by all three oncogenic drivers. CAMOR promoted viability and migration specifically in cancer cells across analyzed cell lines and tumor types. Mechanistically, CAMOR and neighboring CARNMT1 form a negative feedback regulatory loop affecting CAMOR oncogenic activity. Distinct downstream gene expression signatures suggested that the studied lncRNAs act through different regulatory processes. Conclusion Our findings expand the repertoire of oncogenic lncRNAs and demonstrate that integrating multiple oncogenic contexts enables identification of both driver-specific and broadly acting lncRNAs, providing a framework for identifying lncRNAs that may contribute to cancer development and represent potential diagnostic or therapeutic targets.

cancer biology↗

bioRxiv2026

Structural Topology-based Electrostatic Model (STEM) Reveals Ion-Coordination Exchange as a Driver of RNA Folding Dynamics

RNA is a highly charged polyelectrolyte whose folding into functional architectures depends on an ionic atmosphere that screens strong electrostatic repulsion along the phosphate backbone. Whereas monovalent ions primarily stabilize secondary structure, divalent magnesium (Mg2+) drives tertiary folding often via site-specific and adopting various dynamic coordination modes. Current RNA structure-prediction frameworks rely largely on static direct-contact information, overlooking ion-mediated interactions and the dynamic exchange between distinct coordination modes--particularly the dynamic exchange between direct (inner) and solvent-separated (outer-sphere) Mg2+-phosphate coordination that often controls RNAs conformational transition. Here, we introduce the Structural-based Electrostatic Model (STEM), a hybrid implicit-explicit framework that explicitly captures how the dynamic exchange between distinct ion-coordination modes dictates folding pathways. STEM combines explicit Mg2+ ions to resolve site-specific interactions with implicit K+ ions to describe counter-ion condensation mediated electrostatic screening through generalized Manning counter-ion condensation model, enabling computationally efficient exploration of RNA folding landscapes. The model accurately reproduces crystallographic ion-binding sites, experimental preferential ion-interaction coefficients, and Small-Angle X-ray Scattering (SAXS)-derived radii of gyration across diverse RNA systems. Applied to a 58-nt rRNA fragment, STEM reveals that folding from an intermediate to the native state is driven by a chelated Mg2+-mediated tertiary contact and captures the resulting coordination-dependent conformational breathing. By shifting the paradigm from static direct-contact descriptions to ion-mediated dynamic interactions, STEM provides a physically grounded framework for predicting dynamic ensembles of RNA structures, resolving their folding free-energy landscapes, and elucidating the mechanisms of RNA folding and function beyond native conformations across physiological salt conditions. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=91 SRC="FIGDIR/small/734987v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@27da3borg.highwire.dtl.DTLVardef@689310org.highwire.dtl.DTLVardef@18f32f0org.highwire.dtl.DTLVardef@593184_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗

bioRxiv2026

A Dual-Function Guanidinium Scaffold that Couples Copper Sequestration with Redox Protection in Wilson disease

Wilson disease (WD) is caused due to mutations in the copper ATPase gene ATP7B, that result in accumulation of labile copper pools and the consequent disruption of cellular redox homeostasis through uncontrolled copper-mediated reactive oxygen species generation. Current therapies mainly depend on high-affinity copper chelation to lower metal burden which sometimes also strip copper from cuproproteins and may disturb physiological copper-dependent processes. It also does not directly suppress pathological copper reactivity i.e., free radical generation, a major driver of WD progression. To overcome these limitations, we have rationally designed Gua-Cu-3, a C-symmetric guanidinium-based molecule that can chelate labile copper without metal stripping from cuproproteins due to moderate binding affinity and it has intrinsic antioxidant activity within a single nanosheet-forming supramolecular self-assembly. Spectroscopic, calorimetric, and computational analyses revealed controlled multivalent copper coordination (Kd = 95.4 M) while radical-scavenging and hydroxyl-radical inhibition assays further revealed potent redox-regulatory activity. In cellular models of copper overload, Gua-Cu-3 treatment reduces ATP7B trafficking from trans-Golgi network, confirming effective intracellular copper sequestration. This was accompanied by a marked reduction in oxidative stress, reduction of translocation of Nrf2 in nucleus and of HO-1 expression, thereby limiting lipid peroxidation which leads to restoration of cellular homeostasis, including improved lysosomal integrity, reduced endoplasmic reticulum stress, decreased mitochondrial superoxide levels, and diminished apoptosis. Importantly, the protective effects extended, beyond cultured cells, Gua-Cu-3 attenuates oxidative stress in ATP7B-homolog-deficient C. elegans and rescues copper-induced developmental defects in zebrafish, outperforming D-penicillamine, which is currently in use for Wilson disease management. These findings establish Gua-Cu-3 as a molecularly designed supramolecular copper-reactivity buffer that couples-controlled copper sequestration with redox regulation which is distinct from conventional copper depletion and provides a framework for treating Wilson disease and other disorders associated with metal dyshomeostasis and oxidative stress.

Cell Biology↗

bioRxiv2023

A common druggable signature of oncogenic CMYC, mutant KRAS and mutant p53 reveals functional redundancy and competition of the oncogenes in cancer

Major driver oncogenes CMYC, mutant KRAS and mutant TP53 often co-exist and cooperate in promoting human neoplasia. By CRISPR-Cas9-mediated downregulation we determined their proteomics and transcriptomics downstream programs in a panel of cell lines with activated either single or three oncogenes - in cancers of lung, colon and pancreas. This allowed to define and screen the oncogenes common functional program for anti-cancer target candidates, and find protocols which efficiently kill cancer cells and organoids by targeting pathways represented by a signature of three genes: RUVBL1, HSPA9 and XPO1. We found that these genes were controlled by the driver oncoproteins in a redundant or competitive manner, rather than by cooperation. Each oncoprotein individually was able to upregulate the three target genes, while upon oncogene co-expression each target was controlled preferably by a specific oncoprotein which reduced the influence of the others. Mechanistically this redundancy was mediated by parallel routes of the target gene activation - as in the case of mutant KRAS signaling to C-JUN and GLI-2 transcription factors bypassing CMYC, and by competition - as in the case of mutant p53 and CMYC competing for biding to the target promoters. The transcriptomics data from the cell lines and patient samples indicate that the redundancy of the oncogenic programs is a broad phenomenon which may comprise even a majority of the genes dependent on the oncoprotein, as shown for mutant p53 in colon and lung cancer cell lines. Nevertheless, we demonstrate that the redundant oncogene programs harbor targets of efficient anti-cancer drug combinations, bypassing limitations of a direct oncoprotein inhibition.

cancer biology↗

bioRxiv2021

HSP70-driven molecular response to the proteasome machinery inhibition is a vulnerability in cancer

Human neoplasias are often addicted to the proteasome machinery. However, cancers have evolved efficient response mechanisms to overcome proteasome inhibition with bortezomib and carfilzomib - drugs approved for multiple myeloma treatment. To understand these responses we investigated proteome changes upon the proteasome inhibition with carfilzomib - in multiple myeloma, normal fibroblasts, and cancers of lung, colon, and pancreas. A pathway-oriented siRNA screen based on the proteomics results showed that molecular chaperones, autophagy- and endocytosis-related proteins are cancer-specific vulnerabilities combined with carfilzomib. Targeting of HSPA1A/B (HSP70 family chaperones) most specifically sensitized cancer cells and patient-derived organoids to the proteasome inhibition. A high level of HSPA1A/B mRNA correlated with a low proteasome activity in cancer patient tissues and is a risk factor in cancer patients with a low proteasome expression. Mechanistically, HSPA1A/B governed autophagy, unfolded protein response, endocytic trafficking, and chaperoned the proteasome machinery, suppressing the effect of the proteasome inhibition, but did not control the NRF1/2-driven proteasome subunit transcriptional bounce-back. Consequently, downregulation of NRF1 most specifically decreased the viability of cancer cells with the inhibited proteasome and HSP70.

cancer biology↗