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Biology subjects

Ho, H. K.

Publications and source records attributed to Ho, H. K..

2 recordsLinked to original sources

Targetable BIRC5 dependency in therapy-resistant TP53 mutated acute myeloid leukemia

TP53 mutations across multiple cancers, including acute myeloid leukemia (AML), are associated with poor outcomes irrespective of treatment modality. However, druggable vulnerabilities beyond canonical p53 targets remain largely unexplored. We identify BIRC5 (encodes survivin), an inhibitor of the apoptosis protein (IAP) family, as a novel vulnerability in TP53 mutant AML using an unbiased, comprehensive multiomics approach -- whole-genome CRISPR knockout screen, bulk and single-cell RNA-seq, proteomics, and high-throughput drug screen. Mechanistically, BIRC5 deletion in AML restored caspase-9 and -3/7 activity and downregulated other IAPs, implicating BIRC5 as the central post-mitochondrial regulator for blocking apoptosis. p53 stabilization suppressed BIRC5 selectively in TP53 wild-type AML, explaining BIRC5 upregulation in TP53 mutant lines and AML primary tumors (n > 700). Longitudinal single-cell RNAseq (n = 22 pairs) revealed expansion of BIRC5high stem and progenitor leukemia clones in TP53 mutant AML patients post-VenAza therapy. Survivin and IAP inhibitors emerged as top combination partners with VenAza in TP53 mutant AML cells and showed potent in vivo leukemic blast inhibition in cell line and patient-derived xenograft models along with primary tumors. Beyond AML, BIRC5 was upregulated broadly across 17 of 25 TP53 mutant cancers in the TCGA cohort, and combination with survivin inhibitors overcame chemotherapy resistance in TP53 deficient triple negative breast and colorectal cancers. These findings define BIRC5 as a critical, targetable dependency and unveil survivin/IAP inhibition as a promising therapeutic axis to overcome p53-related resistance across both hematologic and solid malignancies. Key PointsO_LIBIRC5 upregulation is a novel dependency in TP53 mutant AML that mediates therapy resistance by evasion of apoptosis. C_LIO_LICombination with Survivin/IAP inhibitors overcomes venetoclax/azacitidine resistance in TP53 mutant AML. C_LI

cancer biology↗

An Evaluation of the In Vitro Roles and Mechanisms of Silibinin in Reducing Pyrazinamide- and Isoniazid-Induced Hepatocellular Damage

Tuberculosis remains a significant infectious lung disease that affects millions of patients worldwide. Despite numerous existing drug regimens for tuberculosis, Drug-Induced Liver Injury is a major challenge that limits the effectiveness of these therapeutics. Two drugs that form the backbone of the commonly administered quadruple antitubercular regimen, i.e. pyrazinamide (PZA) and isoniazid (INH), are associated with such hepatotoxicity. The problem is compounded by the lack of safe and effective alternatives to the antitubercular regimen. Consequently, current research largely focuses on exploiting the hepatoprotective effect of nutraceutical compounds as complementary therapy. Silibinin, a herbal product widely believed to protect against various liver diseases, potentially provides a useful solution given its hepatoprotective mechanisms. In our study, we identified silibinins role in mitigating PZA- and INH-induced hepatotoxicity and elucidated a deeper mechanistic understanding of silibinins hepatoprotective ability. 25 M silibinin preserved the viability of human foetal hepatocyte line LO2 when co-administered with 80 mM INH and decreased apoptosis induced by a combination of 40 mM INH and 10 mM PZA by reducing oxidative damage to mitochondria, proteins, and lipids. Taken together, this proof-of-concept forms the rational basis for the further investigation of silibinins hepatoprotective effect in subsequent preclinical studies and clinical trials. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=133 SRC="FIGDIR/small/815241v3_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@7dde5borg.highwire.dtl.DTLVardef@1914a77org.highwire.dtl.DTLVardef@1aff684org.highwire.dtl.DTLVardef@1616fa5_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗