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Dhanasekaran, R.

Publications and source records attributed to Dhanasekaran, R..

4 recordsLinked to original sources

A Niclosamide Prodrug SSL-0024 with Enhanced Bioavailability Suppresses Hepatocellular Carcinoma via Multi-Pathway Signaling Inhibition

BackgroundHepatocellular carcinoma (HCC) remains a leading cause of cancer-related mortality worldwide, underscoring the urgent need for effective therapies. The FDA-approved anthelmintic, niclosamide, is a promising repurposed drug candidate for HCC; however, its clinical application in solid tumors is hampered by poor aqueous solubility and resulting low bioavailability. MethodsWe designed and screened eight novel niclosamide prodrug candidates for solubility, stability, and anti-proliferative activity in HCC cell lines. The lead compound, SSL-0024, was evaluated for pharmacokinetics and anti-tumor efficacy in an orthotopic patient-derived xenograft (PDX) model, and for cytotoxicity in patient-derived organoids (PDOs). Mechanistic studies assessed AKT-mTOR-STAT3 and other related signaling pathways. ResultsThe O-sulfate derivative, SSL-0024, demonstrated improved solubility and pH stability, and a sustained release of niclosamide over [~]48 h. Once-daily oral administration of SSL-0024 (100 mg/kg) achieved [~]60% tumor growth inhibition in PDX models at [~]46.8% of the niclosamide ethanolamine dose, with minimal toxicity. It also induced significantly greater cytotoxicity than sorafenib (p<0.05) in the PDO. Mechanistically, SSL-0024 suppressed major oncogenic pathways including AKT-mTOR-STAT3, RAF, and Wnt/{beta}-catenin. ConclusionsSSL-0024 overcomes key pharmacokinetic limitations of niclosamide while maintaining potent anti-tumor activity, supporting its further development as an orally bioavailable therapeutic candidate for HCC.

cancer biology↗

Modeling patient tissues at molecular resolution with Eva

Tissue structure is essential to function and homeostasis in all organs, and disruptions to structure usually indicate disease. Modeling relationships between structural, molecular, and clinical aspects of tissues could advance new diagnostics and treatment strategies. Although profiling techniques like spatial proteomics can capture these relationships, the data remain challenging to extract insight from. Here, we present Eva, a foundation model for tissue imaging data that learns multi-scale spatial representations of tissues at the molecular, cellular, and sample level. Eva uses a novel vision transformer architecture and is pre-trained on masked reconstruction of over 40 million matched spatial proteomics and histopathology images. We show that Eva excels at a variety of tasks, including cross-modal inference from H&E to proteomics stains, quality control, data annotation, zero-shot retrieval, survival modeling, and patient stratification. Extensive evaluations on held-out validation data demonstrate the versatility and generalizability of the learned embeddings. We anticipate that Eva will accelerate translational science by bridging basic research and clinical practice.

bioinformatics↗

MYC Overexpression Drives Immune Evasion in Human Cancer that is Reversible Through Restoration of Pro-Inflammatory Macrophages

Cancers evade immune surveillance that in some, but not in many, cases can be reversed through immune checkpoint therapy. Here we report that the MYC oncogene suppresses immune surveillance, activates immune checkpoint expression, and predicts responsiveness to immune checkpoint inhibition. First, when MYC is genomically amplified and overexpressed in 33 different human cancers, this increases immune checkpoint expression, drives immune checkpoint therapeutic resistance, and is associated with both Th2-like immune profile, and reduced CD8 T cell infiltration. Second, experimentally, MYC-driven tumors suppress pro-inflammatory antigen-presenting macrophages with increased CD40 and MHCII expression, which in turn impedes T cell response. This MYC-driven suppression of macrophages can be reversed by combined but not individual blockade of PDL1 and CTLA4. Third, the depletion of macrophages abrogated the anti-neoplastic effects of PDL1 and CTLA4 blockade. Hence, MYC is a predictor of immune checkpoint responsiveness and a key driver of immune evasion through the suppression of pro-inflammatory macrophages. The immune evasion by MYC can be overcome by combined PDL1 and CTLA4 blockade. Statement of SignificanceMYC is the most commonly activated oncogene in human cancers. In this study, we identify macrophage-mediated immune evasion as a major therapeutic vulnerability of MYC-driven cancers. Our results have implications for developing effective immunotherapies for MYC-driven human cancers and also for prioritizing patients with MYC-driven tumors for combination immunotherapy.

cancer biology↗

MYC Functions as a Switch for Natural Killer Cell-Mediated Immune Surveillance of Lymphoid Malignancies

The MYC oncogene drives T and B lymphoid malignancies, including Burkitts lymphoma (BL) and Acute Lymphoblastic Leukemia (ALL). Using CyTOF, we demonstrate a systemic reduction in natural killer (NK) cell-mediated surveillance in SR-tTA/Tet-O-MYCON mice bearing MYC-driven T-lymphomas, due to an arrest in NK cell maturation. Inactivation of lymphoma-intrinsic MYC releases the brakes on NK maturation restoring NK homeostasis. Lymphoma-intrinsic MYC arrests NK maturation by transcriptionally repressing STAT1/2 and secretion of Type I Interferons (IFNs). Treating T-lymphoma-bearing mice with Type I IFN improves survival by rescuing NK cell maturation. In MYC-driven BL patients, low expression of both STAT1 and STAT2 correlates significantly with the absence of activated NK cells and predicts unfavorable clinical outcomes. Adoptive transfer of mature NK cells is sufficient to delay both T-lymphoma growth and recurrence post MYC inactivation. Our studies thus provide a rationale for developing NK cell-based therapies to effectively treat MYC-driven lymphomas in the future.\n\nAbbreviations

cancer biology↗