Characterized by the accumulation of somatic mutations in blood cell lineages, clonal hematopoiesis of indeterminate potential (CHIP) is frequent in aging and involves the expansion of mutated hematopoietic stem and progenitor cells (HSC/Ps) that leads to an increased risk of hematologic malignancy. However, the risk factors that contribute to CHIP-associated clonal hematopoiesis (CH) are poorly understood. Obesity induces a proinflammatory state and fatty bone marrow (FBM), which may influence CHIP-associated pathologies. We analyzed exome sequencing and clinical data for 47,466 individuals with validated CHIP in the UK Biobank. CHIP was present in 5.8% of the study population and was associated with a significant increase in the waist-to-hip ratio (WHR). Mouse models of obesity and CHIP driven by heterozygosity of Tet2, Dnmt3a, Asxl1, and Jak2 resulted in exacerbated expansion of mutant HSC/Ps due in part to excessive inflammation. Our results show that obesity is highly associated with CHIP and that a proinflammatory state could potentiate the progression of CHIP to more significant hematologic neoplasia. The calcium channel blockers nifedipine and SKF-96365, either alone or in combination with metformin, MCC950, or anakinra (IL-1 receptor antagonist), suppressed the growth of mutant CHIP cells and partially restored normal hematopoiesis. Targeting CHIP-mutant cells with these drugs could be a potential therapeutic approach to treat CH and its associated abnormalities in individuals with obesity.

Loss-of-function mutations in the DNA methyltransferase 3A (DNMT3A ) are seen in a large number of patients with acute myeloid leukemia (AML) with normal cytogenetics and are frequently associated with poor prognosis. DNMT3A mutations are an early preleukemic event, which — when combined with other genetic lesions — result in full-blown leukemia. Here, we show that loss of Dnmt3a in hematopoietic stem and progenitor cells (HSC/Ps) results in myeloproliferation, which is associated with hyperactivation of the phosphatidylinositol 3-kinase (PI3K) pathway. PI3Kα/β or the PI3Kα/δ inhibitor treatment partially corrects myeloproliferation, although the partial rescue is more efficient in response to the PI3Kα/β inhibitor treatment. In vivo RNA-Seq analysis on drug-treated Dnmt3a ^–/– HSC/Ps showed a reduction in the expression of genes associated with chemokines, inflammation, cell attachment, and extracellular matrix compared with controls. Remarkably, drug-treated leukemic mice showed a reversal in the enhanced fetal liver HSC-like gene signature observed in vehicle-treated Dnmt3a ^–/– LSK cells as well as a reduction in the expression of genes involved in regulating actin cytoskeleton-based functions, including the RHO/RAC GTPases. In a human PDX model bearing DNMT3A mutant AML, PI3Kα/β inhibitor treatment prolonged their survival and rescued the leukemic burden. Our results identify a potentially new target for treating DNMT3A mutation–driven myeloid malignancies.

Targeting the challenging tumors lacking explicit markers and predictors for chemosensitivity is one of the major impediments of the current cancer armamentarium. Triple-negative breast cancer (TNBC) is an aggressive and challenging molecular subtype of breast cancer, which needs astute strategies to achieve clinical success. The pro-survival B-cell lymphoma 2 (BCL-2) overexpression reported in TNBC plays a central role in deterring apoptosis and is a promising target. Here, we propose three novel BH4 mimetic small molecules, SM396, a covalent binder, and two non-covalent binders, i.e., SM216 and SM949, which show high binding affinity (nM) and selectivity, designed by remodeling the existing BCL-2 chemical space. Our mechanistic studies validate the selectivity of the compounds towards cancerous cells and not on normal cells. A series of functional assays illustrated BCL-2-mediated apoptosis in the tumor cells as a potent anti-cancerous mechanism. Moreover, the compounds exhibited efficacious in vivo activity as single agents in the MDA-MB-231 xenograft model (at nanomolar dosage). Overall, these findings depict SM216, SM396, and SM949 as promising leads, pointing to the clinical translation of these compounds in targeting triple-negative breast cancer.

Most of the triple-negative phenotypes or basal-like molecular subtypes of breast cancers are associated with aggressive clinical behavior and show poor disease prognosis. Current treatment options are constrained, emphasizing the need for novel combinatorial therapies for this particular tumor subtype. Our group has demonstrated that functionally active p21–activated kinase 1 (PAK1) exhibits significantly higher expression levels in clinical triple-negative breast cancer (TNBC) samples compared with other subtypes, as well as adjacent normal tissues. Low PAK1 expression in TNBC was significantly linked to better prognosis, with improved overall survival (P = 0.00236) and relapse-free survival (P = 0.0314), as shown by Gene expression–based Outcome for Breast cancer Online analysis. To confirm the role of PAK1 as a therapeutic target and to discover novel synergistic chemotherapy drug combinations, we conducted a drug combination screen using TNBC cell lines and a mouse metastatic tumor cell line. We identified the combined inhibition of PAK1 inhibitor NVS-PAK1 with doxorubicin/paclitaxel/methotrexate as a synergistic novel therapeutic approach for treating metastatic TNBC to improve overall survival. This study also indicated a reduction in the effective dosage of the chemotherapeutic drug when combined with NVS-PAK1. Our study demonstrates that combining NVS-PAK1 with each individual chemotherapeutic drug such as doxorubicin, paclitaxel, and methotrexate resulted in decreased colony formation, reduced wound-healing capability, and diminished migratory and invasive potential in both TNBC cell lines and 4T1 in vitro. These findings were further validated in orthotopic mouse mammary tumors, confirming that simultaneous PAK1 inhibition alongside chemotherapy significantly enhanced antitumor efficacy and reduced metastasis.

Clonal hematopoiesis of indeterminate potential (CHIP) is characterized by age-related somatic mutations in hematopoietic stem and progenitor cells (HSC/Ps) and is correlated with an increased risk of myeloid malignancies, elevated inflammatory pathways in circulating myeloid cells, higher all-cause mortality, chronic kidney disease, and cardiovascular disease. The pathophysiology of inflammatory bowel disease (IBD) is intrinsically linked to heightened inflammation. Nevertheless, the presence of CHIP in IBD and its role in the pathophysiology of IBD remains poorly elucidated. In the UK Biobank, CHIP was associated with an increased incidence of IBD. Females with CHIP had a 1.33-fold higher risk, which was further validated in the All of Us database (ßodds ratio, 1.29). For Crohn's disease, DNA methyltransferase 3A (DNMT3A) mutations conferred a 1.81-fold increased incidence in females compared with non-DNMT3A carriers, which rose to 2.09 for large clones (variant allele fraction of ≥10%). In contrast, for ulcerative colitis, TET2 large clones were significantly associated, and only among individuals aged <45 years. These associations were further identified using 2-sample Mendelian randomization. In a mouse model of CHIP-IBD, HSC/Ps with Dnmt3a mutation demonstrated significantly worse pathophysiology compared with controls, due, in part, to heightened expression of apurinic/apyrimidinic endonuclease 1 (APE1) in the bone marrow and colon. Treatment with the APE1/redox factor 1 inhibitor APX3330 ameliorated CHIP-IBD driven by the Dnmt3a mutation.