Osimertinib Covalently Binds to CD34 and Eliminates Myeloid Leukemia Stem/Progenitor Cells.

Osimertinib is a third-generation covalent EGFR inhibitor that is used in treating non-small cell lung cancer. First-generation EGFR inhibitors were found to elicit pro-differentiation effect on acute myeloid leukemia (AML) cells in preclinical studies, but clinical trials yielded mostly negative results. Here, we report that osimertinib selectively induced apoptosis of CD34+ leukemia stem/progenitor cells but not CD34- cells in EGFR-negative AML and chronic myeloid leukemia (CML). Covalent binding of osimertinib to CD34 at cysteines 199 and 177 and suppression of Src family kinases (SFK) and downstream STAT3 activation contributed to osimertinib-induced cell death. SFK and STAT3 inhibition induced synthetic lethality with osimertinib in primary CD34+ cells. CD34 expression was elevated in AML cells compared with their normal counterparts. Genomic, transcriptomic, and proteomic profiling identified mutation and gene expression signatures of patients with AML with high CD34 expression, and univariate and multivariate analyses indicated the adverse prognostic significance of high expression of CD34. Osimertinib treatment induced responses in AML patient-derived xenograft models that correlated with CD34 expression while sparing normal CD34+ cells. Clinical responses were observed in two patients with CD34high AML who were treated with osimertinib on a compassionate-use basis. These findings reveal the therapeutic potential of osimertinib for treating CD34high AML and CML and describe an EGFR-independent mechanism of osimertinib-induced cell death in myeloid leukemia. SIGNIFICANCE: Osimertinib binds CD34 and selectively kills CD34+ leukemia cells to induce remission in preclinical models and patients with AML with a high percentage of CD34+ blasts, providing therapeutic options for myeloid leukemia patients.

Adult Laryngeal Pleomorphic Rhabdomyosarcoma: A Rare Entity.

Rhabdomyosarcoma (RMS) is a rare and aggressive cancerous tumor that arises from embryonal mesenchymal cells with skeletal muscle differentiation, and it is exceedingly rare that occurs specifically in the larynx. To date, only 22 instances of laryngeal pleomorphic RMSs have been documented in adults. Consequently, there is limited information available to assist healthcare professionals in effectively handling RMS in the larynx of adult patients. Here, we present an uncommon occurrence involving a 45-year-old man who experienced progressive hoarseness and received a diagnosis of pleomorphic RMS affecting the larynx. Pleomorphic RMS had been pathologically diagnosed after a vertical hemilaryngectomy. Following the surgical intervention, the patient underwent chemotherapy and radiation therapy. As of now, there have been no indications of tumor recurrence.

Clerodane-type Diterpene Glycosides from Dicranopteris pedata.

Three new clerodane-type diterpene glycosides, (5R,6S,8R,9S,10R)-6-O-[ß-D-glucopyranosyl-(1 → 4)-α-L-rhamnopyranosyl]cleroda-3,13(16),14-diene (1), (5R,6S,8R,9S,10R,13S)-6-O-[ß-D-glucopyranosyl-(1 → 4)-α-L-rhamnopyranosyl]-2-ox-oneocleroda-3,13-dien-15-ol (2), (5R,6S,8R,9S,10R)-6-O-[ß-D-glucopyranosyl-(1 → 4)-α-L-rhamnopyranosyl]-(13E)-2-oxoneocleroda-3,14-dien-13-ol (3), together with two known compounds 4 and 5 were isolated from Dicranopteris pedata. The structures of these compounds were elucidated by detailed spectroscopic analysis, and the absolute configuration of compound 2 was determined by ECD calculations. In addition, compound 1 exhibited weak inhibitory activities against SMMC-7721, MCF-7 and SW480.

Shexiang Tongxin Dropping Pill () Reduces Coronary Microembolization in Rats via Regulation of Mitochondrial Permeability Transition Pore Opening and AKT-GSK3ß Phosphorylation.

OBJECTIVE: To investigate the protective effects of Shexiang Tongxin Dropping Pill (, STDP) following sodium laurate-induced coronary microembolization (CME) in rats. METHODS: Forty rats were divided into 4 groups: the control (sham) group, CME group, low-dose STDP pretreatment group (20 mg·kg-1·d-1), and high-dose STDP pretreatment group (40 mg·kg-1·d-1). The rats were intragastric administrated with STDP 2 weeks before operation. Moreover, the histopathological alterations were observed using optical microscopy and transmission electron microscopy. Antioxidant biomarkers were analyzed by enzyme-linked immunosorbent assay. Mitochondrial functions including the mitochondrial permeability transition pore (mPTP) mtDNA copy number were determined and proteins of AKT/GSK3ß were analyzed by Western blot. RESULTS: The rats in the CME group showed a significant increase in the fibrinogen-like protein 2 expression level and mitochondrial dysfunction and a decrease in the expression level of antioxidant biomarkers (superoxide dismutase and catalase, P<0.01 for all). In contrast, the rats in the low- and high-dose STDP pretreatment groups showed a significant decrease in coronary microthrombi (P<0.05); moreover, STDP restored the antioxidant-related protein activities and mitochondrial function, inhibited mPTP opening, decreased AKT-Ser473 phosphorylation, and increased GSK3ß-Ser9 phosphorylation (P<0.05 or P<0.01). CONCLUSION: STDP may be useful for treatment of CME, possibly via regulation of mPTP opening and AKT/GSK3ß phosphorylation.